Initial import of abandoned HQEMU version 2.5.2HEADmaster

40 files changed, 11399 insertions, 0 deletions

diff --git a/src/slirp/COPYRIGHT b/src/slirp/COPYRIGHT
new file mode 100644
index 0000000..1bc83d4
--- /dev/null
+++ b/src/slirp/COPYRIGHT
@@ -0,0 +1,61 @@
+Slirp was written by Danny Gasparovski.
+Copyright (c), 1995,1996 All Rights Reserved.
+
+Slirp is maintained by Kelly Price <tygris+slirp@erols.com>
+
+Slirp is free software; "free" as in you don't have to pay for it, and you
+are free to do whatever you want with it.  I do not accept any donations,
+monetary or otherwise, for Slirp.  Instead, I would ask you to pass this
+potential donation to your favorite charity.  In fact, I encourage
+*everyone* who finds Slirp useful to make a small donation to their
+favorite charity (for example, GreenPeace).  This is not a requirement, but
+a suggestion from someone who highly values the service they provide.
+
+The copyright terms and conditions:
+
+---BEGIN---
+
+ Copyright (c) 1995,1996 Danny Gasparovski.  All rights reserved.
+
+ Redistribution and use in source and binary forms, with or without
+ modification, are permitted provided that the following conditions
+ are met:
+ 1. Redistributions of source code must retain the above copyright
+    notice, this list of conditions and the following disclaimer.
+ 2. Redistributions in binary form must reproduce the above copyright
+    notice, this list of conditions and the following disclaimer in the
+    documentation and/or other materials provided with the distribution.
+
+ THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
+ AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
+ DANNY GASPAROVSKI OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+---END---
+
+This basically means you can do anything you want with the software, except
+1) call it your own, and 2) claim warranty on it.  There is no warranty for
+this software.  None.  Nada.  If you lose a million dollars while using
+Slirp, that's your loss not mine.  So, ***USE AT YOUR OWN RISK!***.
+
+If these conditions cannot be met due to legal restrictions (E.g. where it
+is against the law to give out Software without warranty), you must cease
+using the software and delete all copies you have.
+
+Slirp uses code that is copyrighted by the following people/organizations:
+
+Juha Pirkola.
+Gregory M. Christy.
+The Regents of the University of California.
+Carnegie Mellon University.
+The Australian National University.
+RSA Data Security, Inc.
+
+Please read the top of each source file for the details on the various
+copyrights.
diff --git a/src/slirp/Makefile.objs b/src/slirp/Makefile.objs
new file mode 100644
index 0000000..2daa9dc
--- /dev/null
+++ b/src/slirp/Makefile.objs
@@ -0,0 +1,3 @@
+common-obj-y = cksum.o if.o ip_icmp.o ip_input.o ip_output.o dnssearch.o
+common-obj-y += slirp.o mbuf.o misc.o sbuf.o socket.o tcp_input.o tcp_output.o
+common-obj-y += tcp_subr.o tcp_timer.o udp.o bootp.o tftp.o arp_table.o
diff --git a/src/slirp/arp_table.c b/src/slirp/arp_table.c
new file mode 100644
index 0000000..bcaeb44
--- /dev/null
+++ b/src/slirp/arp_table.c
@@ -0,0 +1,89 @@
+/*
+ * ARP table
+ *
+ * Copyright (c) 2011 AdaCore
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "slirp.h"
+
+void arp_table_add(Slirp *slirp, uint32_t ip_addr, uint8_t ethaddr[ETH_ALEN])
+{
+    const uint32_t broadcast_addr =
+        ~slirp->vnetwork_mask.s_addr | slirp->vnetwork_addr.s_addr;
+    ArpTable *arptbl = &slirp->arp_table;
+    int i;
+
+    DEBUG_CALL("arp_table_add");
+    DEBUG_ARG("ip = 0x%x", ip_addr);
+    DEBUG_ARGS((dfd, " hw addr = %02x:%02x:%02x:%02x:%02x:%02x\n",
+                ethaddr[0], ethaddr[1], ethaddr[2],
+                ethaddr[3], ethaddr[4], ethaddr[5]));
+
+    if (ip_addr == 0 || ip_addr == 0xffffffff || ip_addr == broadcast_addr) {
+        /* Do not register broadcast addresses */
+        return;
+    }
+
+    /* Search for an entry */
+    for (i = 0; i < ARP_TABLE_SIZE; i++) {
+        if (arptbl->table[i].ar_sip == ip_addr) {
+            /* Update the entry */
+            memcpy(arptbl->table[i].ar_sha, ethaddr, ETH_ALEN);
+            return;
+        }
+    }
+
+    /* No entry found, create a new one */
+    arptbl->table[arptbl->next_victim].ar_sip = ip_addr;
+    memcpy(arptbl->table[arptbl->next_victim].ar_sha,  ethaddr, ETH_ALEN);
+    arptbl->next_victim = (arptbl->next_victim + 1) % ARP_TABLE_SIZE;
+}
+
+bool arp_table_search(Slirp *slirp, uint32_t ip_addr,
+                      uint8_t out_ethaddr[ETH_ALEN])
+{
+    const uint32_t broadcast_addr =
+        ~slirp->vnetwork_mask.s_addr | slirp->vnetwork_addr.s_addr;
+    ArpTable *arptbl = &slirp->arp_table;
+    int i;
+
+    DEBUG_CALL("arp_table_search");
+    DEBUG_ARG("ip = 0x%x", ip_addr);
+
+    /* If broadcast address */
+    if (ip_addr == 0xffffffff || ip_addr == broadcast_addr) {
+        /* return Ethernet broadcast address */
+        memset(out_ethaddr, 0xff, ETH_ALEN);
+        return 1;
+    }
+
+    for (i = 0; i < ARP_TABLE_SIZE; i++) {
+        if (arptbl->table[i].ar_sip == ip_addr) {
+            memcpy(out_ethaddr, arptbl->table[i].ar_sha,  ETH_ALEN);
+            DEBUG_ARGS((dfd, " found hw addr = %02x:%02x:%02x:%02x:%02x:%02x\n",
+                        out_ethaddr[0], out_ethaddr[1], out_ethaddr[2],
+                        out_ethaddr[3], out_ethaddr[4], out_ethaddr[5]));
+            return 1;
+        }
+    }
+
+    return 0;
+}
diff --git a/src/slirp/bootp.c b/src/slirp/bootp.c
new file mode 100644
index 0000000..1baaab1
--- /dev/null
+++ b/src/slirp/bootp.c
@@ -0,0 +1,338 @@
+/*
+ * QEMU BOOTP/DHCP server
+ *
+ * Copyright (c) 2004 Fabrice Bellard
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+#include <slirp.h>
+
+#if defined(_WIN32)
+/* Windows ntohl() returns an u_long value.
+ * Add a type cast to match the format strings. */
+# define ntohl(n) ((uint32_t)ntohl(n))
+#endif
+
+/* XXX: only DHCP is supported */
+
+#define LEASE_TIME (24 * 3600)
+
+static const uint8_t rfc1533_cookie[] = { RFC1533_COOKIE };
+
+#ifdef DEBUG
+#define DPRINTF(fmt, ...) \
+do if (slirp_debug & DBG_CALL) { fprintf(dfd, fmt, ##  __VA_ARGS__); fflush(dfd); } while (0)
+#else
+#define DPRINTF(fmt, ...) do{}while(0)
+#endif
+
+static BOOTPClient *get_new_addr(Slirp *slirp, struct in_addr *paddr,
+                                 const uint8_t *macaddr)
+{
+    BOOTPClient *bc;
+    int i;
+
+    for(i = 0; i < NB_BOOTP_CLIENTS; i++) {
+        bc = &slirp->bootp_clients[i];
+        if (!bc->allocated || !memcmp(macaddr, bc->macaddr, 6))
+            goto found;
+    }
+    return NULL;
+ found:
+    bc = &slirp->bootp_clients[i];
+    bc->allocated = 1;
+    paddr->s_addr = slirp->vdhcp_startaddr.s_addr + htonl(i);
+    return bc;
+}
+
+static BOOTPClient *request_addr(Slirp *slirp, const struct in_addr *paddr,
+                                 const uint8_t *macaddr)
+{
+    uint32_t req_addr = ntohl(paddr->s_addr);
+    uint32_t dhcp_addr = ntohl(slirp->vdhcp_startaddr.s_addr);
+    BOOTPClient *bc;
+
+    if (req_addr >= dhcp_addr &&
+        req_addr < (dhcp_addr + NB_BOOTP_CLIENTS)) {
+        bc = &slirp->bootp_clients[req_addr - dhcp_addr];
+        if (!bc->allocated || !memcmp(macaddr, bc->macaddr, 6)) {
+            bc->allocated = 1;
+            return bc;
+        }
+    }
+    return NULL;
+}
+
+static BOOTPClient *find_addr(Slirp *slirp, struct in_addr *paddr,
+                              const uint8_t *macaddr)
+{
+    BOOTPClient *bc;
+    int i;
+
+    for(i = 0; i < NB_BOOTP_CLIENTS; i++) {
+        if (!memcmp(macaddr, slirp->bootp_clients[i].macaddr, 6))
+            goto found;
+    }
+    return NULL;
+ found:
+    bc = &slirp->bootp_clients[i];
+    bc->allocated = 1;
+    paddr->s_addr = slirp->vdhcp_startaddr.s_addr + htonl(i);
+    return bc;
+}
+
+static void dhcp_decode(const struct bootp_t *bp, int *pmsg_type,
+                        struct in_addr *preq_addr)
+{
+    const uint8_t *p, *p_end;
+    int len, tag;
+
+    *pmsg_type = 0;
+    preq_addr->s_addr = htonl(0L);
+
+    p = bp->bp_vend;
+    p_end = p + DHCP_OPT_LEN;
+    if (memcmp(p, rfc1533_cookie, 4) != 0)
+        return;
+    p += 4;
+    while (p < p_end) {
+        tag = p[0];
+        if (tag == RFC1533_PAD) {
+            p++;
+        } else if (tag == RFC1533_END) {
+            break;
+        } else {
+            p++;
+            if (p >= p_end)
+                break;
+            len = *p++;
+            DPRINTF("dhcp: tag=%d len=%d\n", tag, len);
+
+            switch(tag) {
+            case RFC2132_MSG_TYPE:
+                if (len >= 1)
+                    *pmsg_type = p[0];
+                break;
+            case RFC2132_REQ_ADDR:
+                if (len >= 4) {
+                    memcpy(&(preq_addr->s_addr), p, 4);
+                }
+                break;
+            default:
+                break;
+            }
+            p += len;
+        }
+    }
+    if (*pmsg_type == DHCPREQUEST && preq_addr->s_addr == htonl(0L) &&
+        bp->bp_ciaddr.s_addr) {
+        memcpy(&(preq_addr->s_addr), &bp->bp_ciaddr, 4);
+    }
+}
+
+static void bootp_reply(Slirp *slirp, const struct bootp_t *bp)
+{
+    BOOTPClient *bc = NULL;
+    struct mbuf *m;
+    struct bootp_t *rbp;
+    struct sockaddr_in saddr, daddr;
+    struct in_addr preq_addr;
+    int dhcp_msg_type, val;
+    uint8_t *q;
+    uint8_t client_ethaddr[ETH_ALEN];
+
+    /* extract exact DHCP msg type */
+    dhcp_decode(bp, &dhcp_msg_type, &preq_addr);
+    DPRINTF("bootp packet op=%d msgtype=%d", bp->bp_op, dhcp_msg_type);
+    if (preq_addr.s_addr != htonl(0L))
+        DPRINTF(" req_addr=%08" PRIx32 "\n", ntohl(preq_addr.s_addr));
+    else
+        DPRINTF("\n");
+
+    if (dhcp_msg_type == 0)
+        dhcp_msg_type = DHCPREQUEST; /* Force reply for old BOOTP clients */
+
+    if (dhcp_msg_type != DHCPDISCOVER &&
+        dhcp_msg_type != DHCPREQUEST)
+        return;
+
+    /* Get client's hardware address from bootp request */
+    memcpy(client_ethaddr, bp->bp_hwaddr, ETH_ALEN);
+
+    m = m_get(slirp);
+    if (!m) {
+        return;
+    }
+    m->m_data += IF_MAXLINKHDR;
+    rbp = (struct bootp_t *)m->m_data;
+    m->m_data += sizeof(struct udpiphdr);
+    memset(rbp, 0, sizeof(struct bootp_t));
+
+    if (dhcp_msg_type == DHCPDISCOVER) {
+        if (preq_addr.s_addr != htonl(0L)) {
+            bc = request_addr(slirp, &preq_addr, client_ethaddr);
+            if (bc) {
+                daddr.sin_addr = preq_addr;
+            }
+        }
+        if (!bc) {
+         new_addr:
+            bc = get_new_addr(slirp, &daddr.sin_addr, client_ethaddr);
+            if (!bc) {
+                DPRINTF("no address left\n");
+                return;
+            }
+        }
+        memcpy(bc->macaddr, client_ethaddr, ETH_ALEN);
+    } else if (preq_addr.s_addr != htonl(0L)) {
+        bc = request_addr(slirp, &preq_addr, client_ethaddr);
+        if (bc) {
+            daddr.sin_addr = preq_addr;
+            memcpy(bc->macaddr, client_ethaddr, ETH_ALEN);
+        } else {
+            /* DHCPNAKs should be sent to broadcast */
+            daddr.sin_addr.s_addr = 0xffffffff;
+        }
+    } else {
+        bc = find_addr(slirp, &daddr.sin_addr, bp->bp_hwaddr);
+        if (!bc) {
+            /* if never assigned, behaves as if it was already
+               assigned (windows fix because it remembers its address) */
+            goto new_addr;
+        }
+    }
+
+    /* Update ARP table for this IP address */
+    arp_table_add(slirp, daddr.sin_addr.s_addr, client_ethaddr);
+
+    saddr.sin_addr = slirp->vhost_addr;
+    saddr.sin_port = htons(BOOTP_SERVER);
+
+    daddr.sin_port = htons(BOOTP_CLIENT);
+
+    rbp->bp_op = BOOTP_REPLY;
+    rbp->bp_xid = bp->bp_xid;
+    rbp->bp_htype = 1;
+    rbp->bp_hlen = 6;
+    memcpy(rbp->bp_hwaddr, bp->bp_hwaddr, ETH_ALEN);
+
+    rbp->bp_yiaddr = daddr.sin_addr; /* Client IP address */
+    rbp->bp_siaddr = saddr.sin_addr; /* Server IP address */
+
+    q = rbp->bp_vend;
+    memcpy(q, rfc1533_cookie, 4);
+    q += 4;
+
+    if (bc) {
+        DPRINTF("%s addr=%08" PRIx32 "\n",
+                (dhcp_msg_type == DHCPDISCOVER) ? "offered" : "ack'ed",
+                ntohl(daddr.sin_addr.s_addr));
+
+        if (dhcp_msg_type == DHCPDISCOVER) {
+            *q++ = RFC2132_MSG_TYPE;
+            *q++ = 1;
+            *q++ = DHCPOFFER;
+        } else /* DHCPREQUEST */ {
+            *q++ = RFC2132_MSG_TYPE;
+            *q++ = 1;
+            *q++ = DHCPACK;
+        }
+
+        if (slirp->bootp_filename)
+            snprintf((char *)rbp->bp_file, sizeof(rbp->bp_file), "%s",
+                     slirp->bootp_filename);
+
+        *q++ = RFC2132_SRV_ID;
+        *q++ = 4;
+        memcpy(q, &saddr.sin_addr, 4);
+        q += 4;
+
+        *q++ = RFC1533_NETMASK;
+        *q++ = 4;
+        memcpy(q, &slirp->vnetwork_mask, 4);
+        q += 4;
+
+        if (!slirp->restricted) {
+            *q++ = RFC1533_GATEWAY;
+            *q++ = 4;
+            memcpy(q, &saddr.sin_addr, 4);
+            q += 4;
+
+            *q++ = RFC1533_DNS;
+            *q++ = 4;
+            memcpy(q, &slirp->vnameserver_addr, 4);
+            q += 4;
+        }
+
+        *q++ = RFC2132_LEASE_TIME;
+        *q++ = 4;
+        val = htonl(LEASE_TIME);
+        memcpy(q, &val, 4);
+        q += 4;
+
+        if (*slirp->client_hostname) {
+            val = strlen(slirp->client_hostname);
+            *q++ = RFC1533_HOSTNAME;
+            *q++ = val;
+            memcpy(q, slirp->client_hostname, val);
+            q += val;
+        }
+
+        if (slirp->vdnssearch) {
+            size_t spaceleft = sizeof(rbp->bp_vend) - (q - rbp->bp_vend);
+            val = slirp->vdnssearch_len;
+            if (val + 1 > spaceleft) {
+                g_warning("DHCP packet size exceeded, "
+                    "omitting domain-search option.");
+            } else {
+                memcpy(q, slirp->vdnssearch, val);
+                q += val;
+            }
+        }
+    } else {
+        static const char nak_msg[] = "requested address not available";
+
+        DPRINTF("nak'ed addr=%08" PRIx32 "\n", ntohl(preq_addr.s_addr));
+
+        *q++ = RFC2132_MSG_TYPE;
+        *q++ = 1;
+        *q++ = DHCPNAK;
+
+        *q++ = RFC2132_MESSAGE;
+        *q++ = sizeof(nak_msg) - 1;
+        memcpy(q, nak_msg, sizeof(nak_msg) - 1);
+        q += sizeof(nak_msg) - 1;
+    }
+    *q = RFC1533_END;
+
+    daddr.sin_addr.s_addr = 0xffffffffu;
+
+    m->m_len = sizeof(struct bootp_t) -
+        sizeof(struct ip) - sizeof(struct udphdr);
+    udp_output2(NULL, m, &saddr, &daddr, IPTOS_LOWDELAY);
+}
+
+void bootp_input(struct mbuf *m)
+{
+    struct bootp_t *bp = mtod(m, struct bootp_t *);
+
+    if (bp->bp_op == BOOTP_REQUEST) {
+        bootp_reply(m->slirp, bp);
+    }
+}
diff --git a/src/slirp/bootp.h b/src/slirp/bootp.h
new file mode 100644
index 0000000..ec3b687
--- /dev/null
+++ b/src/slirp/bootp.h
@@ -0,0 +1,126 @@
+/* bootp/dhcp defines */
+#ifndef SLIRP_BOOTP_H
+#define SLIRP_BOOTP_H 1
+
+#define BOOTP_SERVER	67
+#define BOOTP_CLIENT	68
+
+#define BOOTP_REQUEST	1
+#define BOOTP_REPLY	2
+
+#define RFC1533_COOKIE		99, 130, 83, 99
+#define RFC1533_PAD		0
+#define RFC1533_NETMASK		1
+#define RFC1533_TIMEOFFSET	2
+#define RFC1533_GATEWAY		3
+#define RFC1533_TIMESERVER	4
+#define RFC1533_IEN116NS	5
+#define RFC1533_DNS		6
+#define RFC1533_LOGSERVER	7
+#define RFC1533_COOKIESERVER	8
+#define RFC1533_LPRSERVER	9
+#define RFC1533_IMPRESSSERVER	10
+#define RFC1533_RESOURCESERVER	11
+#define RFC1533_HOSTNAME	12
+#define RFC1533_BOOTFILESIZE	13
+#define RFC1533_MERITDUMPFILE	14
+#define RFC1533_DOMAINNAME	15
+#define RFC1533_SWAPSERVER	16
+#define RFC1533_ROOTPATH	17
+#define RFC1533_EXTENSIONPATH	18
+#define RFC1533_IPFORWARDING	19
+#define RFC1533_IPSOURCEROUTING	20
+#define RFC1533_IPPOLICYFILTER	21
+#define RFC1533_IPMAXREASSEMBLY	22
+#define RFC1533_IPTTL		23
+#define RFC1533_IPMTU		24
+#define RFC1533_IPMTUPLATEAU	25
+#define RFC1533_INTMTU		26
+#define RFC1533_INTLOCALSUBNETS	27
+#define RFC1533_INTBROADCAST	28
+#define RFC1533_INTICMPDISCOVER	29
+#define RFC1533_INTICMPRESPOND	30
+#define RFC1533_INTROUTEDISCOVER 31
+#define RFC1533_INTROUTESOLICIT	32
+#define RFC1533_INTSTATICROUTES	33
+#define RFC1533_LLTRAILERENCAP	34
+#define RFC1533_LLARPCACHETMO	35
+#define RFC1533_LLETHERNETENCAP	36
+#define RFC1533_TCPTTL		37
+#define RFC1533_TCPKEEPALIVETMO	38
+#define RFC1533_TCPKEEPALIVEGB	39
+#define RFC1533_NISDOMAIN	40
+#define RFC1533_NISSERVER	41
+#define RFC1533_NTPSERVER	42
+#define RFC1533_VENDOR		43
+#define RFC1533_NBNS		44
+#define RFC1533_NBDD		45
+#define RFC1533_NBNT		46
+#define RFC1533_NBSCOPE		47
+#define RFC1533_XFS		48
+#define RFC1533_XDM		49
+
+#define RFC2132_REQ_ADDR	50
+#define RFC2132_LEASE_TIME      51
+#define RFC2132_MSG_TYPE	53
+#define RFC2132_SRV_ID		54
+#define RFC2132_PARAM_LIST	55
+#define RFC2132_MESSAGE		56
+#define RFC2132_MAX_SIZE	57
+#define RFC2132_RENEWAL_TIME    58
+#define RFC2132_REBIND_TIME     59
+
+#define DHCPDISCOVER		1
+#define DHCPOFFER		2
+#define DHCPREQUEST		3
+#define DHCPACK			5
+#define DHCPNAK			6
+
+#define RFC1533_VENDOR_MAJOR	0
+#define RFC1533_VENDOR_MINOR	0
+
+#define RFC1533_VENDOR_MAGIC	128
+#define RFC1533_VENDOR_ADDPARM	129
+#define	RFC1533_VENDOR_ETHDEV	130
+#define RFC1533_VENDOR_HOWTO    132
+#define RFC1533_VENDOR_MNUOPTS	160
+#define RFC1533_VENDOR_SELECTION 176
+#define RFC1533_VENDOR_MOTD	184
+#define RFC1533_VENDOR_NUMOFMOTD 8
+#define RFC1533_VENDOR_IMG	192
+#define RFC1533_VENDOR_NUMOFIMG	16
+
+#define RFC1533_END		255
+#define BOOTP_VENDOR_LEN	64
+#define DHCP_OPT_LEN		312
+
+struct bootp_t {
+    struct ip ip;
+    struct udphdr udp;
+    uint8_t bp_op;
+    uint8_t bp_htype;
+    uint8_t bp_hlen;
+    uint8_t bp_hops;
+    uint32_t bp_xid;
+    uint16_t bp_secs;
+    uint16_t unused;
+    struct in_addr bp_ciaddr;
+    struct in_addr bp_yiaddr;
+    struct in_addr bp_siaddr;
+    struct in_addr bp_giaddr;
+    uint8_t bp_hwaddr[16];
+    uint8_t bp_sname[64];
+    uint8_t bp_file[128];
+    uint8_t bp_vend[DHCP_OPT_LEN];
+};
+
+typedef struct {
+    uint16_t allocated;
+    uint8_t macaddr[6];
+} BOOTPClient;
+
+#define NB_BOOTP_CLIENTS 16
+
+void bootp_input(struct mbuf *m);
+
+#endif
diff --git a/src/slirp/cksum.c b/src/slirp/cksum.c
new file mode 100644
index 0000000..6328660
--- /dev/null
+++ b/src/slirp/cksum.c
@@ -0,0 +1,139 @@
+/*
+ * Copyright (c) 1988, 1992, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)in_cksum.c	8.1 (Berkeley) 6/10/93
+ * in_cksum.c,v 1.2 1994/08/02 07:48:16 davidg Exp
+ */
+
+#include <slirp.h>
+
+/*
+ * Checksum routine for Internet Protocol family headers (Portable Version).
+ *
+ * This routine is very heavily used in the network
+ * code and should be modified for each CPU to be as fast as possible.
+ *
+ * XXX Since we will never span more than 1 mbuf, we can optimise this
+ */
+
+#define ADDCARRY(x)  (x > 65535 ? x -= 65535 : x)
+#define REDUCE {l_util.l = sum; sum = l_util.s[0] + l_util.s[1];        \
+        (void)ADDCARRY(sum);}
+
+int cksum(struct mbuf *m, int len)
+{
+	register uint16_t *w;
+	register int sum = 0;
+	register int mlen = 0;
+	int byte_swapped = 0;
+
+	union {
+		uint8_t  c[2];
+		uint16_t s;
+	} s_util;
+	union {
+		uint16_t s[2];
+		uint32_t l;
+	} l_util;
+
+	if (m->m_len == 0)
+	   goto cont;
+	w = mtod(m, uint16_t *);
+
+	mlen = m->m_len;
+
+	if (len < mlen)
+	   mlen = len;
+#ifdef DEBUG
+	len -= mlen;
+#endif
+	/*
+	 * Force to even boundary.
+	 */
+	if ((1 & (uintptr_t)w) && (mlen > 0)) {
+		REDUCE;
+		sum <<= 8;
+		s_util.c[0] = *(uint8_t *)w;
+		w = (uint16_t *)((int8_t *)w + 1);
+		mlen--;
+		byte_swapped = 1;
+	}
+	/*
+	 * Unroll the loop to make overhead from
+	 * branches &c small.
+	 */
+	while ((mlen -= 32) >= 0) {
+		sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
+		sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
+		sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11];
+		sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15];
+		w += 16;
+	}
+	mlen += 32;
+	while ((mlen -= 8) >= 0) {
+		sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
+		w += 4;
+	}
+	mlen += 8;
+	if (mlen == 0 && byte_swapped == 0)
+	   goto cont;
+	REDUCE;
+	while ((mlen -= 2) >= 0) {
+		sum += *w++;
+	}
+
+	if (byte_swapped) {
+		REDUCE;
+		sum <<= 8;
+		if (mlen == -1) {
+			s_util.c[1] = *(uint8_t *)w;
+			sum += s_util.s;
+			mlen = 0;
+		} else
+
+		   mlen = -1;
+	} else if (mlen == -1)
+	   s_util.c[0] = *(uint8_t *)w;
+
+cont:
+#ifdef DEBUG
+	if (len) {
+		DEBUG_ERROR((dfd, "cksum: out of data\n"));
+		DEBUG_ERROR((dfd, " len = %d\n", len));
+	}
+#endif
+	if (mlen == -1) {
+		/* The last mbuf has odd # of bytes. Follow the
+		 standard (the odd byte may be shifted left by 8 bits
+			   or not as determined by endian-ness of the machine) */
+		s_util.c[1] = 0;
+		sum += s_util.s;
+	}
+	REDUCE;
+	return (~sum & 0xffff);
+}
diff --git a/src/slirp/debug.h b/src/slirp/debug.h
new file mode 100644
index 0000000..6cfa61e
--- /dev/null
+++ b/src/slirp/debug.h
@@ -0,0 +1,34 @@
+/*
+ * Copyright (c) 1995 Danny Gasparovski.
+ *
+ * Please read the file COPYRIGHT for the
+ * terms and conditions of the copyright.
+ */
+
+//#define DEBUG 1
+
+#ifdef DEBUG
+
+#define DBG_CALL 0x1
+#define DBG_MISC 0x2
+#define DBG_ERROR 0x4
+
+#define dfd stderr
+
+extern int slirp_debug;
+
+#define DEBUG_CALL(x) if (slirp_debug & DBG_CALL) { fprintf(dfd, "%s...\n", x); fflush(dfd); }
+#define DEBUG_ARG(x, y) if (slirp_debug & DBG_CALL) { fputc(' ', dfd); fprintf(dfd, x, y); fputc('\n', dfd); fflush(dfd); }
+#define DEBUG_ARGS(x) if (slirp_debug & DBG_CALL) { fprintf x ; fflush(dfd); }
+#define DEBUG_MISC(x) if (slirp_debug & DBG_MISC) { fprintf x ; fflush(dfd); }
+#define DEBUG_ERROR(x) if (slirp_debug & DBG_ERROR) {fprintf x ; fflush(dfd); }
+
+#else
+
+#define DEBUG_CALL(x)
+#define DEBUG_ARG(x, y)
+#define DEBUG_ARGS(x)
+#define DEBUG_MISC(x)
+#define DEBUG_ERROR(x)
+
+#endif
diff --git a/src/slirp/dnssearch.c b/src/slirp/dnssearch.c
new file mode 100644
index 0000000..4c9064e
--- /dev/null
+++ b/src/slirp/dnssearch.c
@@ -0,0 +1,314 @@
+/*
+ * Domain search option for DHCP (RFC 3397)
+ *
+ * Copyright (c) 2012 Klaus Stengel
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <glib.h>
+#include "slirp.h"
+
+static const uint8_t RFC3397_OPT_DOMAIN_SEARCH = 119;
+static const uint8_t MAX_OPT_LEN = 255;
+static const uint8_t OPT_HEADER_LEN = 2;
+static const uint8_t REFERENCE_LEN = 2;
+
+struct compact_domain;
+
+typedef struct compact_domain {
+    struct compact_domain *self;
+    struct compact_domain *refdom;
+    uint8_t *labels;
+    size_t len;
+    size_t common_octets;
+} CompactDomain;
+
+static size_t
+domain_suffix_diffoff(const CompactDomain *a, const CompactDomain *b)
+{
+    size_t la = a->len, lb = b->len;
+    uint8_t *da = a->labels + la, *db = b->labels + lb;
+    size_t i, lm = (la < lb) ? la : lb;
+
+    for (i = 0; i < lm; i++) {
+        da--; db--;
+        if (*da != *db) {
+            break;
+        }
+    }
+    return i;
+}
+
+static int domain_suffix_ord(const void *cva, const void *cvb)
+{
+    const CompactDomain *a = cva, *b = cvb;
+    size_t la = a->len, lb = b->len;
+    size_t doff = domain_suffix_diffoff(a, b);
+    uint8_t ca = a->labels[la - doff];
+    uint8_t cb = b->labels[lb - doff];
+
+    if (ca < cb) {
+        return -1;
+    }
+    if (ca > cb) {
+        return 1;
+    }
+    if (la < lb) {
+        return -1;
+    }
+    if (la > lb) {
+        return 1;
+    }
+    return 0;
+}
+
+static size_t domain_common_label(CompactDomain *a, CompactDomain *b)
+{
+    size_t res, doff = domain_suffix_diffoff(a, b);
+    uint8_t *first_eq_pos = a->labels + (a->len - doff);
+    uint8_t *label = a->labels;
+
+    while (*label && label < first_eq_pos) {
+        label += *label + 1;
+    }
+    res = a->len - (label - a->labels);
+    /* only report if it can help to reduce the packet size */
+    return (res > REFERENCE_LEN) ? res : 0;
+}
+
+static void domain_fixup_order(CompactDomain *cd, size_t n)
+{
+    size_t i;
+
+    for (i = 0; i < n; i++) {
+        CompactDomain *cur = cd + i, *next = cd[i].self;
+
+        while (!cur->common_octets) {
+            CompactDomain *tmp = next->self; /* backup target value */
+
+            next->self = cur;
+            cur->common_octets++;
+
+            cur = next;
+            next = tmp;
+        }
+    }
+}
+
+static void domain_mklabels(CompactDomain *cd, const char *input)
+{
+    uint8_t *len_marker = cd->labels;
+    uint8_t *output = len_marker; /* pre-incremented */
+    const char *in = input;
+    char cur_chr;
+    size_t len = 0;
+
+    if (cd->len == 0) {
+        goto fail;
+    }
+    cd->len++;
+
+    do {
+        cur_chr = *in++;
+        if (cur_chr == '.' || cur_chr == '\0') {
+            len = output - len_marker;
+            if ((len == 0 && cur_chr == '.') || len >= 64) {
+                goto fail;
+            }
+            *len_marker = len;
+
+            output++;
+            len_marker = output;
+        } else {
+            output++;
+            *output = cur_chr;
+        }
+    } while (cur_chr != '\0');
+
+    /* ensure proper zero-termination */
+    if (len != 0) {
+        *len_marker = 0;
+        cd->len++;
+    }
+    return;
+
+fail:
+    g_warning("failed to parse domain name '%s'\n", input);
+    cd->len = 0;
+}
+
+static void
+domain_mkxrefs(CompactDomain *doms, CompactDomain *last, size_t depth)
+{
+    CompactDomain *i = doms, *target = doms;
+
+    do {
+        if (i->labels < target->labels) {
+            target = i;
+        }
+    } while (i++ != last);
+
+    for (i = doms; i != last; i++) {
+        CompactDomain *group_last;
+        size_t next_depth;
+
+        if (i->common_octets == depth) {
+            continue;
+        }
+
+        next_depth = -1;
+        for (group_last = i; group_last != last; group_last++) {
+            size_t co = group_last->common_octets;
+            if (co <= depth) {
+                break;
+            }
+            if (co < next_depth) {
+                next_depth = co;
+            }
+        }
+        domain_mkxrefs(i, group_last, next_depth);
+
+        i = group_last;
+        if (i == last) {
+            break;
+        }
+    }
+
+    if (depth == 0) {
+        return;
+    }
+
+    i = doms;
+    do {
+        if (i != target && i->refdom == NULL) {
+            i->refdom = target;
+            i->common_octets = depth;
+        }
+    } while (i++ != last);
+}
+
+static size_t domain_compactify(CompactDomain *domains, size_t n)
+{
+    uint8_t *start = domains->self->labels, *outptr = start;
+    size_t i;
+
+    for (i = 0; i < n; i++) {
+        CompactDomain *cd = domains[i].self;
+        CompactDomain *rd = cd->refdom;
+
+        if (rd != NULL) {
+            size_t moff = (rd->labels - start)
+                    + (rd->len - cd->common_octets);
+            if (moff < 0x3FFFu) {
+                cd->len -= cd->common_octets - 2;
+                cd->labels[cd->len - 1] = moff & 0xFFu;
+                cd->labels[cd->len - 2] = 0xC0u | (moff >> 8);
+            }
+        }
+
+        if (cd->labels != outptr) {
+            memmove(outptr, cd->labels, cd->len);
+            cd->labels = outptr;
+        }
+        outptr += cd->len;
+    }
+    return outptr - start;
+}
+
+int translate_dnssearch(Slirp *s, const char **names)
+{
+    size_t blocks, bsrc_start, bsrc_end, bdst_start;
+    size_t i, num_domains, memreq = 0;
+    uint8_t *result = NULL, *outptr;
+    CompactDomain *domains = NULL;
+    const char **nameptr = names;
+
+    while (*nameptr != NULL) {
+        nameptr++;
+    }
+
+    num_domains = nameptr - names;
+    if (num_domains == 0) {
+        return -2;
+    }
+
+    domains = g_malloc(num_domains * sizeof(*domains));
+
+    for (i = 0; i < num_domains; i++) {
+        size_t nlen = strlen(names[i]);
+        memreq += nlen + 2; /* 1 zero octet + 1 label length octet */
+        domains[i].self = domains + i;
+        domains[i].len = nlen;
+        domains[i].common_octets = 0;
+        domains[i].refdom = NULL;
+    }
+
+    /* reserve extra 2 header bytes for each 255 bytes of output */
+    memreq += ((memreq + MAX_OPT_LEN - 1) / MAX_OPT_LEN) * OPT_HEADER_LEN;
+    result = g_malloc(memreq * sizeof(*result));
+
+    outptr = result;
+    for (i = 0; i < num_domains; i++) {
+        domains[i].labels = outptr;
+        domain_mklabels(domains + i, names[i]);
+        outptr += domains[i].len;
+    }
+
+    if (outptr == result) {
+        g_free(domains);
+        g_free(result);
+        return -1;
+    }
+
+    qsort(domains, num_domains, sizeof(*domains), domain_suffix_ord);
+    domain_fixup_order(domains, num_domains);
+
+    for (i = 1; i < num_domains; i++) {
+        size_t cl = domain_common_label(domains + i - 1, domains + i);
+        domains[i - 1].common_octets = cl;
+    }
+
+    domain_mkxrefs(domains, domains + num_domains - 1, 0);
+    memreq = domain_compactify(domains, num_domains);
+
+    blocks = (memreq + MAX_OPT_LEN - 1) / MAX_OPT_LEN;
+    bsrc_end = memreq;
+    bsrc_start = (blocks - 1) * MAX_OPT_LEN;
+    bdst_start = bsrc_start + blocks * OPT_HEADER_LEN;
+    memreq += blocks * OPT_HEADER_LEN;
+
+    while (blocks--) {
+        size_t len = bsrc_end - bsrc_start;
+        memmove(result + bdst_start, result + bsrc_start, len);
+        result[bdst_start - 2] = RFC3397_OPT_DOMAIN_SEARCH;
+        result[bdst_start - 1] = len;
+        bsrc_end = bsrc_start;
+        bsrc_start -= MAX_OPT_LEN;
+        bdst_start -= MAX_OPT_LEN + OPT_HEADER_LEN;
+    }
+
+    g_free(domains);
+    s->vdnssearch = result;
+    s->vdnssearch_len = memreq;
+    return 0;
+}
diff --git a/src/slirp/if.c b/src/slirp/if.c
new file mode 100644
index 0000000..8325a2a
--- /dev/null
+++ b/src/slirp/if.c
@@ -0,0 +1,237 @@
+/*
+ * Copyright (c) 1995 Danny Gasparovski.
+ *
+ * Please read the file COPYRIGHT for the
+ * terms and conditions of the copyright.
+ */
+
+#include <slirp.h>
+#include "qemu/timer.h"
+
+static void
+ifs_insque(struct mbuf *ifm, struct mbuf *ifmhead)
+{
+	ifm->ifs_next = ifmhead->ifs_next;
+	ifmhead->ifs_next = ifm;
+	ifm->ifs_prev = ifmhead;
+	ifm->ifs_next->ifs_prev = ifm;
+}
+
+static void
+ifs_remque(struct mbuf *ifm)
+{
+	ifm->ifs_prev->ifs_next = ifm->ifs_next;
+	ifm->ifs_next->ifs_prev = ifm->ifs_prev;
+}
+
+void
+if_init(Slirp *slirp)
+{
+    slirp->if_fastq.ifq_next = slirp->if_fastq.ifq_prev = &slirp->if_fastq;
+    slirp->if_batchq.ifq_next = slirp->if_batchq.ifq_prev = &slirp->if_batchq;
+    slirp->next_m = &slirp->if_batchq;
+}
+
+/*
+ * if_output: Queue packet into an output queue.
+ * There are 2 output queue's, if_fastq and if_batchq.
+ * Each output queue is a doubly linked list of double linked lists
+ * of mbufs, each list belonging to one "session" (socket).  This
+ * way, we can output packets fairly by sending one packet from each
+ * session, instead of all the packets from one session, then all packets
+ * from the next session, etc.  Packets on the if_fastq get absolute
+ * priority, but if one session hogs the link, it gets "downgraded"
+ * to the batchq until it runs out of packets, then it'll return
+ * to the fastq (eg. if the user does an ls -alR in a telnet session,
+ * it'll temporarily get downgraded to the batchq)
+ */
+void
+if_output(struct socket *so, struct mbuf *ifm)
+{
+	Slirp *slirp = ifm->slirp;
+	struct mbuf *ifq;
+	int on_fastq = 1;
+
+	DEBUG_CALL("if_output");
+	DEBUG_ARG("so = %p", so);
+	DEBUG_ARG("ifm = %p", ifm);
+
+	/*
+	 * First remove the mbuf from m_usedlist,
+	 * since we're gonna use m_next and m_prev ourselves
+	 * XXX Shouldn't need this, gotta change dtom() etc.
+	 */
+	if (ifm->m_flags & M_USEDLIST) {
+		remque(ifm);
+		ifm->m_flags &= ~M_USEDLIST;
+	}
+
+	/*
+	 * See if there's already a batchq list for this session.
+	 * This can include an interactive session, which should go on fastq,
+	 * but gets too greedy... hence it'll be downgraded from fastq to batchq.
+	 * We mustn't put this packet back on the fastq (or we'll send it out of order)
+	 * XXX add cache here?
+	 */
+	for (ifq = slirp->if_batchq.ifq_prev; ifq != &slirp->if_batchq;
+	     ifq = ifq->ifq_prev) {
+		if (so == ifq->ifq_so) {
+			/* A match! */
+			ifm->ifq_so = so;
+			ifs_insque(ifm, ifq->ifs_prev);
+			goto diddit;
+		}
+	}
+
+	/* No match, check which queue to put it on */
+	if (so && (so->so_iptos & IPTOS_LOWDELAY)) {
+		ifq = slirp->if_fastq.ifq_prev;
+		on_fastq = 1;
+		/*
+		 * Check if this packet is a part of the last
+		 * packet's session
+		 */
+		if (ifq->ifq_so == so) {
+			ifm->ifq_so = so;
+			ifs_insque(ifm, ifq->ifs_prev);
+			goto diddit;
+		}
+        } else {
+		ifq = slirp->if_batchq.ifq_prev;
+                /* Set next_m if the queue was empty so far */
+                if (slirp->next_m == &slirp->if_batchq) {
+                    slirp->next_m = ifm;
+                }
+        }
+
+	/* Create a new doubly linked list for this session */
+	ifm->ifq_so = so;
+	ifs_init(ifm);
+	insque(ifm, ifq);
+
+diddit:
+	if (so) {
+		/* Update *_queued */
+		so->so_queued++;
+		so->so_nqueued++;
+		/*
+		 * Check if the interactive session should be downgraded to
+		 * the batchq.  A session is downgraded if it has queued 6
+		 * packets without pausing, and at least 3 of those packets
+		 * have been sent over the link
+		 * (XXX These are arbitrary numbers, probably not optimal..)
+		 */
+		if (on_fastq && ((so->so_nqueued >= 6) &&
+				 (so->so_nqueued - so->so_queued) >= 3)) {
+
+			/* Remove from current queue... */
+			remque(ifm->ifs_next);
+
+			/* ...And insert in the new.  That'll teach ya! */
+			insque(ifm->ifs_next, &slirp->if_batchq);
+		}
+	}
+
+#ifndef FULL_BOLT
+	/*
+	 * This prevents us from malloc()ing too many mbufs
+	 */
+	if_start(ifm->slirp);
+#endif
+}
+
+/*
+ * Send a packet
+ * We choose a packet based on its position in the output queues;
+ * If there are packets on the fastq, they are sent FIFO, before
+ * everything else.  Otherwise we choose the first packet from the
+ * batchq and send it.  the next packet chosen will be from the session
+ * after this one, then the session after that one, and so on..  So,
+ * for example, if there are 3 ftp session's fighting for bandwidth,
+ * one packet will be sent from the first session, then one packet
+ * from the second session, then one packet from the third, then back
+ * to the first, etc. etc.
+ */
+void if_start(Slirp *slirp)
+{
+    uint64_t now = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
+    bool from_batchq, next_from_batchq;
+    struct mbuf *ifm, *ifm_next, *ifqt;
+
+    DEBUG_CALL("if_start");
+
+    if (slirp->if_start_busy) {
+        return;
+    }
+    slirp->if_start_busy = true;
+
+    if (slirp->if_fastq.ifq_next != &slirp->if_fastq) {
+        ifm_next = slirp->if_fastq.ifq_next;
+        next_from_batchq = false;
+    } else if (slirp->next_m != &slirp->if_batchq) {
+        /* Nothing on fastq, pick up from batchq via next_m */
+        ifm_next = slirp->next_m;
+        next_from_batchq = true;
+    } else {
+        ifm_next = NULL;
+    }
+
+    while (ifm_next) {
+        ifm = ifm_next;
+        from_batchq = next_from_batchq;
+
+        ifm_next = ifm->ifq_next;
+        if (ifm_next == &slirp->if_fastq) {
+            /* No more packets in fastq, switch to batchq */
+            ifm_next = slirp->next_m;
+            next_from_batchq = true;
+        }
+        if (ifm_next == &slirp->if_batchq) {
+            /* end of batchq */
+            ifm_next = NULL;
+        }
+
+        /* Try to send packet unless it already expired */
+        if (ifm->expiration_date >= now && !if_encap(slirp, ifm)) {
+            /* Packet is delayed due to pending ARP resolution */
+            continue;
+        }
+
+        if (ifm == slirp->next_m) {
+            /* Set which packet to send on next iteration */
+            slirp->next_m = ifm->ifq_next;
+        }
+
+        /* Remove it from the queue */
+        ifqt = ifm->ifq_prev;
+        remque(ifm);
+
+        /* If there are more packets for this session, re-queue them */
+        if (ifm->ifs_next != ifm) {
+            struct mbuf *next = ifm->ifs_next;
+
+            insque(next, ifqt);
+            ifs_remque(ifm);
+
+            if (!from_batchq) {
+                /* Next packet in fastq is from the same session */
+                ifm_next = next;
+                next_from_batchq = false;
+            } else if (slirp->next_m == &slirp->if_batchq) {
+                /* Set next_m and ifm_next if the session packet is now the
+                 * only one on batchq */
+                slirp->next_m = ifm_next = next;
+            }
+        }
+
+        /* Update so_queued */
+        if (ifm->ifq_so && --ifm->ifq_so->so_queued == 0) {
+            /* If there's no more queued, reset nqueued */
+            ifm->ifq_so->so_nqueued = 0;
+        }
+
+        m_free(ifm);
+    }
+
+    slirp->if_start_busy = false;
+}
diff --git a/src/slirp/if.h b/src/slirp/if.h
new file mode 100644
index 0000000..3327023
--- /dev/null
+++ b/src/slirp/if.h
@@ -0,0 +1,23 @@
+/*
+ * Copyright (c) 1995 Danny Gasparovski.
+ *
+ * Please read the file COPYRIGHT for the
+ * terms and conditions of the copyright.
+ */
+
+#ifndef _IF_H_
+#define _IF_H_
+
+#define IF_COMPRESS	0x01	/* We want compression */
+#define IF_NOCOMPRESS	0x02	/* Do not do compression */
+#define IF_AUTOCOMP	0x04	/* Autodetect (default) */
+#define IF_NOCIDCOMP	0x08	/* CID compression */
+
+#define IF_MTU 1500
+#define IF_MRU 1500
+#define	IF_COMP IF_AUTOCOMP	/* Flags for compression */
+
+/* 2 for alignment, 14 for ethernet, 40 for TCP/IP */
+#define IF_MAXLINKHDR (2 + 14 + 40)
+
+#endif
diff --git a/src/slirp/ip.h b/src/slirp/ip.h
new file mode 100644
index 0000000..e2ee5e3
--- /dev/null
+++ b/src/slirp/ip.h
@@ -0,0 +1,249 @@
+/*
+ * Copyright (c) 1982, 1986, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)ip.h	8.1 (Berkeley) 6/10/93
+ * ip.h,v 1.3 1994/08/21 05:27:30 paul Exp
+ */
+
+#ifndef _IP_H_
+#define _IP_H_
+
+#ifdef HOST_WORDS_BIGENDIAN
+# undef NTOHL
+# undef NTOHS
+# undef HTONL
+# undef HTONS
+# define NTOHL(d)
+# define NTOHS(d)
+# define HTONL(d)
+# define HTONS(d)
+#else
+# ifndef NTOHL
+#  define NTOHL(d) ((d) = ntohl((d)))
+# endif
+# ifndef NTOHS
+#  define NTOHS(d) ((d) = ntohs((uint16_t)(d)))
+# endif
+# ifndef HTONL
+#  define HTONL(d) ((d) = htonl((d)))
+# endif
+# ifndef HTONS
+#  define HTONS(d) ((d) = htons((uint16_t)(d)))
+# endif
+#endif
+
+typedef uint32_t n_long;                 /* long as received from the net */
+
+/*
+ * Definitions for internet protocol version 4.
+ * Per RFC 791, September 1981.
+ */
+#define	IPVERSION	4
+
+/*
+ * Structure of an internet header, naked of options.
+ */
+struct ip {
+#ifdef HOST_WORDS_BIGENDIAN
+	uint8_t ip_v:4,			/* version */
+		ip_hl:4;		/* header length */
+#else
+	uint8_t ip_hl:4,		/* header length */
+		ip_v:4;			/* version */
+#endif
+	uint8_t		ip_tos;			/* type of service */
+	uint16_t	ip_len;			/* total length */
+	uint16_t	ip_id;			/* identification */
+	uint16_t	ip_off;			/* fragment offset field */
+#define	IP_DF 0x4000			/* don't fragment flag */
+#define	IP_MF 0x2000			/* more fragments flag */
+#define	IP_OFFMASK 0x1fff		/* mask for fragmenting bits */
+	uint8_t ip_ttl;			/* time to live */
+	uint8_t ip_p;			/* protocol */
+	uint16_t	ip_sum;			/* checksum */
+	struct	in_addr ip_src,ip_dst;	/* source and dest address */
+} QEMU_PACKED;
+
+#define	IP_MAXPACKET	65535		/* maximum packet size */
+
+/*
+ * Definitions for IP type of service (ip_tos)
+ */
+#define	IPTOS_LOWDELAY		0x10
+#define	IPTOS_THROUGHPUT	0x08
+#define	IPTOS_RELIABILITY	0x04
+
+/*
+ * Definitions for options.
+ */
+#define	IPOPT_COPIED(o)		((o)&0x80)
+#define	IPOPT_CLASS(o)		((o)&0x60)
+#define	IPOPT_NUMBER(o)		((o)&0x1f)
+
+#define	IPOPT_CONTROL		0x00
+#define	IPOPT_RESERVED1		0x20
+#define	IPOPT_DEBMEAS		0x40
+#define	IPOPT_RESERVED2		0x60
+
+#define	IPOPT_EOL		0		/* end of option list */
+#define	IPOPT_NOP		1		/* no operation */
+
+#define	IPOPT_RR		7		/* record packet route */
+#define	IPOPT_TS		68		/* timestamp */
+#define	IPOPT_SECURITY		130		/* provide s,c,h,tcc */
+#define	IPOPT_LSRR		131		/* loose source route */
+#define	IPOPT_SATID		136		/* satnet id */
+#define	IPOPT_SSRR		137		/* strict source route */
+
+/*
+ * Offsets to fields in options other than EOL and NOP.
+ */
+#define	IPOPT_OPTVAL		0		/* option ID */
+#define	IPOPT_OLEN		1		/* option length */
+#define IPOPT_OFFSET		2		/* offset within option */
+#define	IPOPT_MINOFF		4		/* min value of above */
+
+/*
+ * Time stamp option structure.
+ */
+struct	ip_timestamp {
+	uint8_t	ipt_code;		/* IPOPT_TS */
+	uint8_t	ipt_len;		/* size of structure (variable) */
+	uint8_t	ipt_ptr;		/* index of current entry */
+#ifdef HOST_WORDS_BIGENDIAN
+	uint8_t	ipt_oflw:4,		/* overflow counter */
+		ipt_flg:4;		/* flags, see below */
+#else
+	uint8_t	ipt_flg:4,		/* flags, see below */
+		ipt_oflw:4;		/* overflow counter */
+#endif
+	union ipt_timestamp {
+		n_long	ipt_time[1];
+		struct	ipt_ta {
+			struct in_addr ipt_addr;
+			n_long ipt_time;
+		} ipt_ta[1];
+	} ipt_timestamp;
+} QEMU_PACKED;
+
+/* flag bits for ipt_flg */
+#define	IPOPT_TS_TSONLY		0		/* timestamps only */
+#define	IPOPT_TS_TSANDADDR	1		/* timestamps and addresses */
+#define	IPOPT_TS_PRESPEC	3		/* specified modules only */
+
+/* bits for security (not byte swapped) */
+#define	IPOPT_SECUR_UNCLASS	0x0000
+#define	IPOPT_SECUR_CONFID	0xf135
+#define	IPOPT_SECUR_EFTO	0x789a
+#define	IPOPT_SECUR_MMMM	0xbc4d
+#define	IPOPT_SECUR_RESTR	0xaf13
+#define	IPOPT_SECUR_SECRET	0xd788
+#define	IPOPT_SECUR_TOPSECRET	0x6bc5
+
+/*
+ * Internet implementation parameters.
+ */
+#define	MAXTTL		255		/* maximum time to live (seconds) */
+#define	IPDEFTTL	64		/* default ttl, from RFC 1340 */
+#define	IPFRAGTTL	60		/* time to live for frags, slowhz */
+#define	IPTTLDEC	1		/* subtracted when forwarding */
+
+#define	IP_MSS		576		/* default maximum segment size */
+
+#if SIZEOF_CHAR_P == 4
+struct mbuf_ptr {
+	struct mbuf *mptr;
+	uint32_t dummy;
+} QEMU_PACKED;
+#else
+struct mbuf_ptr {
+	struct mbuf *mptr;
+} QEMU_PACKED;
+#endif
+struct qlink {
+	void *next, *prev;
+};
+
+/*
+ * Overlay for ip header used by other protocols (tcp, udp).
+ */
+struct ipovly {
+	struct mbuf_ptr ih_mbuf;	/* backpointer to mbuf */
+	uint8_t	ih_x1;			/* (unused) */
+	uint8_t	ih_pr;			/* protocol */
+	uint16_t	ih_len;			/* protocol length */
+	struct	in_addr ih_src;		/* source internet address */
+	struct	in_addr ih_dst;		/* destination internet address */
+} QEMU_PACKED;
+
+/*
+ * Ip reassembly queue structure.  Each fragment
+ * being reassembled is attached to one of these structures.
+ * They are timed out after ipq_ttl drops to 0, and may also
+ * be reclaimed if memory becomes tight.
+ * size 28 bytes
+ */
+struct ipq {
+        struct qlink frag_link;			/* to ip headers of fragments */
+	struct qlink ip_link;				/* to other reass headers */
+	uint8_t	ipq_ttl;		/* time for reass q to live */
+	uint8_t	ipq_p;			/* protocol of this fragment */
+	uint16_t	ipq_id;			/* sequence id for reassembly */
+	struct	in_addr ipq_src,ipq_dst;
+} QEMU_PACKED;
+
+/*
+ * Ip header, when holding a fragment.
+ *
+ * Note: ipf_link must be at same offset as frag_link above
+ */
+struct	ipasfrag {
+	struct qlink ipf_link;
+	struct ip ipf_ip;
+} QEMU_PACKED;
+
+#define ipf_off      ipf_ip.ip_off
+#define ipf_tos      ipf_ip.ip_tos
+#define ipf_len      ipf_ip.ip_len
+#define ipf_next     ipf_link.next
+#define ipf_prev     ipf_link.prev
+
+/*
+ * Structure stored in mbuf in inpcb.ip_options
+ * and passed to ip_output when ip options are in use.
+ * The actual length of the options (including ipopt_dst)
+ * is in m_len.
+ */
+#define MAX_IPOPTLEN	40
+
+struct ipoption {
+	struct	in_addr ipopt_dst;	/* first-hop dst if source routed */
+	int8_t	ipopt_list[MAX_IPOPTLEN];	/* options proper */
+} QEMU_PACKED;
+
+#endif
diff --git a/src/slirp/ip_icmp.c b/src/slirp/ip_icmp.c
new file mode 100644
index 0000000..23b9f0f
--- /dev/null
+++ b/src/slirp/ip_icmp.c
@@ -0,0 +1,450 @@
+/*
+ * Copyright (c) 1982, 1986, 1988, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)ip_icmp.c	8.2 (Berkeley) 1/4/94
+ * ip_icmp.c,v 1.7 1995/05/30 08:09:42 rgrimes Exp
+ */
+
+#include "slirp.h"
+#include "ip_icmp.h"
+
+/* The message sent when emulating PING */
+/* Be nice and tell them it's just a pseudo-ping packet */
+static const char icmp_ping_msg[] = "This is a pseudo-PING packet used by Slirp to emulate ICMP ECHO-REQUEST packets.\n";
+
+/* list of actions for icmp_error() on RX of an icmp message */
+static const int icmp_flush[19] = {
+/*  ECHO REPLY (0)  */   0,
+		         1,
+		         1,
+/* DEST UNREACH (3) */   1,
+/* SOURCE QUENCH (4)*/   1,
+/* REDIRECT (5) */       1,
+		         1,
+		         1,
+/* ECHO (8) */           0,
+/* ROUTERADVERT (9) */   1,
+/* ROUTERSOLICIT (10) */ 1,
+/* TIME EXCEEDED (11) */ 1,
+/* PARAMETER PROBLEM (12) */ 1,
+/* TIMESTAMP (13) */     0,
+/* TIMESTAMP REPLY (14) */ 0,
+/* INFO (15) */          0,
+/* INFO REPLY (16) */    0,
+/* ADDR MASK (17) */     0,
+/* ADDR MASK REPLY (18) */ 0
+};
+
+void icmp_init(Slirp *slirp)
+{
+    slirp->icmp.so_next = slirp->icmp.so_prev = &slirp->icmp;
+    slirp->icmp_last_so = &slirp->icmp;
+}
+
+void icmp_cleanup(Slirp *slirp)
+{
+    while (slirp->icmp.so_next != &slirp->icmp) {
+        icmp_detach(slirp->icmp.so_next);
+    }
+}
+
+static int icmp_send(struct socket *so, struct mbuf *m, int hlen)
+{
+    struct ip *ip = mtod(m, struct ip *);
+    struct sockaddr_in addr;
+
+    so->s = qemu_socket(AF_INET, SOCK_DGRAM, IPPROTO_ICMP);
+    if (so->s == -1) {
+        return -1;
+    }
+
+    so->so_m = m;
+    so->so_faddr = ip->ip_dst;
+    so->so_laddr = ip->ip_src;
+    so->so_iptos = ip->ip_tos;
+    so->so_type = IPPROTO_ICMP;
+    so->so_state = SS_ISFCONNECTED;
+    so->so_expire = curtime + SO_EXPIRE;
+
+    addr.sin_family = AF_INET;
+    addr.sin_addr = so->so_faddr;
+
+    insque(so, &so->slirp->icmp);
+
+    if (sendto(so->s, m->m_data + hlen, m->m_len - hlen, 0,
+               (struct sockaddr *)&addr, sizeof(addr)) == -1) {
+        DEBUG_MISC((dfd, "icmp_input icmp sendto tx errno = %d-%s\n",
+                    errno, strerror(errno)));
+        icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_NET, 0, strerror(errno));
+        icmp_detach(so);
+    }
+
+    return 0;
+}
+
+void icmp_detach(struct socket *so)
+{
+    closesocket(so->s);
+    sofree(so);
+}
+
+/*
+ * Process a received ICMP message.
+ */
+void
+icmp_input(struct mbuf *m, int hlen)
+{
+  register struct icmp *icp;
+  register struct ip *ip=mtod(m, struct ip *);
+  int icmplen=ip->ip_len;
+  Slirp *slirp = m->slirp;
+
+  DEBUG_CALL("icmp_input");
+  DEBUG_ARG("m = %p", m);
+  DEBUG_ARG("m_len = %d", m->m_len);
+
+  /*
+   * Locate icmp structure in mbuf, and check
+   * that its not corrupted and of at least minimum length.
+   */
+  if (icmplen < ICMP_MINLEN) {          /* min 8 bytes payload */
+  freeit:
+    m_free(m);
+    goto end_error;
+  }
+
+  m->m_len -= hlen;
+  m->m_data += hlen;
+  icp = mtod(m, struct icmp *);
+  if (cksum(m, icmplen)) {
+    goto freeit;
+  }
+  m->m_len += hlen;
+  m->m_data -= hlen;
+
+  DEBUG_ARG("icmp_type = %d", icp->icmp_type);
+  switch (icp->icmp_type) {
+  case ICMP_ECHO:
+    ip->ip_len += hlen;	             /* since ip_input subtracts this */
+    if (ip->ip_dst.s_addr == slirp->vhost_addr.s_addr) {
+      icmp_reflect(m);
+    } else if (slirp->restricted) {
+        goto freeit;
+    } else {
+      struct socket *so;
+      struct sockaddr_in addr;
+      if ((so = socreate(slirp)) == NULL) goto freeit;
+      if (icmp_send(so, m, hlen) == 0) {
+        return;
+      }
+      if(udp_attach(so) == -1) {
+	DEBUG_MISC((dfd,"icmp_input udp_attach errno = %d-%s\n",
+		    errno,strerror(errno)));
+	sofree(so);
+	m_free(m);
+	goto end_error;
+      }
+      so->so_m = m;
+      so->so_faddr = ip->ip_dst;
+      so->so_fport = htons(7);
+      so->so_laddr = ip->ip_src;
+      so->so_lport = htons(9);
+      so->so_iptos = ip->ip_tos;
+      so->so_type = IPPROTO_ICMP;
+      so->so_state = SS_ISFCONNECTED;
+
+      /* Send the packet */
+      addr.sin_family = AF_INET;
+      if ((so->so_faddr.s_addr & slirp->vnetwork_mask.s_addr) ==
+          slirp->vnetwork_addr.s_addr) {
+	/* It's an alias */
+	if (so->so_faddr.s_addr == slirp->vnameserver_addr.s_addr) {
+	  if (get_dns_addr(&addr.sin_addr) < 0)
+	    addr.sin_addr = loopback_addr;
+	} else {
+	  addr.sin_addr = loopback_addr;
+	}
+      } else {
+	addr.sin_addr = so->so_faddr;
+      }
+      addr.sin_port = so->so_fport;
+      if(sendto(so->s, icmp_ping_msg, strlen(icmp_ping_msg), 0,
+		(struct sockaddr *)&addr, sizeof(addr)) == -1) {
+	DEBUG_MISC((dfd,"icmp_input udp sendto tx errno = %d-%s\n",
+		    errno,strerror(errno)));
+	icmp_error(m, ICMP_UNREACH,ICMP_UNREACH_NET, 0,strerror(errno));
+	udp_detach(so);
+      }
+    } /* if ip->ip_dst.s_addr == alias_addr.s_addr */
+    break;
+  case ICMP_UNREACH:
+    /* XXX? report error? close socket? */
+  case ICMP_TIMXCEED:
+  case ICMP_PARAMPROB:
+  case ICMP_SOURCEQUENCH:
+  case ICMP_TSTAMP:
+  case ICMP_MASKREQ:
+  case ICMP_REDIRECT:
+    m_free(m);
+    break;
+
+  default:
+    m_free(m);
+  } /* swith */
+
+end_error:
+  /* m is m_free()'d xor put in a socket xor or given to ip_send */
+  return;
+}
+
+
+/*
+ *	Send an ICMP message in response to a situation
+ *
+ *	RFC 1122: 3.2.2	MUST send at least the IP header and 8 bytes of header. MAY send more (we do).
+ *			MUST NOT change this header information.
+ *			MUST NOT reply to a multicast/broadcast IP address.
+ *			MUST NOT reply to a multicast/broadcast MAC address.
+ *			MUST reply to only the first fragment.
+ */
+/*
+ * Send ICMP_UNREACH back to the source regarding msrc.
+ * mbuf *msrc is used as a template, but is NOT m_free()'d.
+ * It is reported as the bad ip packet.  The header should
+ * be fully correct and in host byte order.
+ * ICMP fragmentation is illegal.  All machines must accept 576 bytes in one
+ * packet.  The maximum payload is 576-20(ip hdr)-8(icmp hdr)=548
+ */
+
+#define ICMP_MAXDATALEN (IP_MSS-28)
+void
+icmp_error(struct mbuf *msrc, u_char type, u_char code, int minsize,
+           const char *message)
+{
+  unsigned hlen, shlen, s_ip_len;
+  register struct ip *ip;
+  register struct icmp *icp;
+  register struct mbuf *m;
+
+  DEBUG_CALL("icmp_error");
+  DEBUG_ARG("msrc = %p", msrc);
+  DEBUG_ARG("msrc_len = %d", msrc->m_len);
+
+  if(type!=ICMP_UNREACH && type!=ICMP_TIMXCEED) goto end_error;
+
+  /* check msrc */
+  if(!msrc) goto end_error;
+  ip = mtod(msrc, struct ip *);
+#ifdef DEBUG
+  { char bufa[20], bufb[20];
+    strcpy(bufa, inet_ntoa(ip->ip_src));
+    strcpy(bufb, inet_ntoa(ip->ip_dst));
+    DEBUG_MISC((dfd, " %.16s to %.16s\n", bufa, bufb));
+  }
+#endif
+  if(ip->ip_off & IP_OFFMASK) goto end_error;    /* Only reply to fragment 0 */
+
+  /* Do not reply to source-only IPs */
+  if ((ip->ip_src.s_addr & htonl(~(0xf << 28))) == 0) {
+      goto end_error;
+  }
+
+  shlen=ip->ip_hl << 2;
+  s_ip_len=ip->ip_len;
+  if(ip->ip_p == IPPROTO_ICMP) {
+    icp = (struct icmp *)((char *)ip + shlen);
+    /*
+     *	Assume any unknown ICMP type is an error. This isn't
+     *	specified by the RFC, but think about it..
+     */
+    if(icp->icmp_type>18 || icmp_flush[icp->icmp_type]) goto end_error;
+  }
+
+  /* make a copy */
+  m = m_get(msrc->slirp);
+  if (!m) {
+      goto end_error;
+  }
+
+  { int new_m_size;
+    new_m_size=sizeof(struct ip )+ICMP_MINLEN+msrc->m_len+ICMP_MAXDATALEN;
+    if(new_m_size>m->m_size) m_inc(m, new_m_size);
+  }
+  memcpy(m->m_data, msrc->m_data, msrc->m_len);
+  m->m_len = msrc->m_len;                        /* copy msrc to m */
+
+  /* make the header of the reply packet */
+  ip  = mtod(m, struct ip *);
+  hlen= sizeof(struct ip );     /* no options in reply */
+
+  /* fill in icmp */
+  m->m_data += hlen;
+  m->m_len -= hlen;
+
+  icp = mtod(m, struct icmp *);
+
+  if(minsize) s_ip_len=shlen+ICMP_MINLEN;   /* return header+8b only */
+  else if(s_ip_len>ICMP_MAXDATALEN)         /* maximum size */
+    s_ip_len=ICMP_MAXDATALEN;
+
+  m->m_len=ICMP_MINLEN+s_ip_len;        /* 8 bytes ICMP header */
+
+  /* min. size = 8+sizeof(struct ip)+8 */
+
+  icp->icmp_type = type;
+  icp->icmp_code = code;
+  icp->icmp_id = 0;
+  icp->icmp_seq = 0;
+
+  memcpy(&icp->icmp_ip, msrc->m_data, s_ip_len);   /* report the ip packet */
+  HTONS(icp->icmp_ip.ip_len);
+  HTONS(icp->icmp_ip.ip_id);
+  HTONS(icp->icmp_ip.ip_off);
+
+#ifdef DEBUG
+  if(message) {           /* DEBUG : append message to ICMP packet */
+    int message_len;
+    char *cpnt;
+    message_len=strlen(message);
+    if(message_len>ICMP_MAXDATALEN) message_len=ICMP_MAXDATALEN;
+    cpnt=(char *)m->m_data+m->m_len;
+    memcpy(cpnt, message, message_len);
+    m->m_len+=message_len;
+  }
+#endif
+
+  icp->icmp_cksum = 0;
+  icp->icmp_cksum = cksum(m, m->m_len);
+
+  m->m_data -= hlen;
+  m->m_len += hlen;
+
+  /* fill in ip */
+  ip->ip_hl = hlen >> 2;
+  ip->ip_len = m->m_len;
+
+  ip->ip_tos=((ip->ip_tos & 0x1E) | 0xC0);  /* high priority for errors */
+
+  ip->ip_ttl = MAXTTL;
+  ip->ip_p = IPPROTO_ICMP;
+  ip->ip_dst = ip->ip_src;    /* ip addresses */
+  ip->ip_src = m->slirp->vhost_addr;
+
+  (void ) ip_output((struct socket *)NULL, m);
+
+end_error:
+  return;
+}
+#undef ICMP_MAXDATALEN
+
+/*
+ * Reflect the ip packet back to the source
+ */
+void
+icmp_reflect(struct mbuf *m)
+{
+  register struct ip *ip = mtod(m, struct ip *);
+  int hlen = ip->ip_hl << 2;
+  int optlen = hlen - sizeof(struct ip );
+  register struct icmp *icp;
+
+  /*
+   * Send an icmp packet back to the ip level,
+   * after supplying a checksum.
+   */
+  m->m_data += hlen;
+  m->m_len -= hlen;
+  icp = mtod(m, struct icmp *);
+
+  icp->icmp_type = ICMP_ECHOREPLY;
+  icp->icmp_cksum = 0;
+  icp->icmp_cksum = cksum(m, ip->ip_len - hlen);
+
+  m->m_data -= hlen;
+  m->m_len += hlen;
+
+  /* fill in ip */
+  if (optlen > 0) {
+    /*
+     * Strip out original options by copying rest of first
+     * mbuf's data back, and adjust the IP length.
+     */
+    memmove((caddr_t)(ip + 1), (caddr_t)ip + hlen,
+	    (unsigned )(m->m_len - hlen));
+    hlen -= optlen;
+    ip->ip_hl = hlen >> 2;
+    ip->ip_len -= optlen;
+    m->m_len -= optlen;
+  }
+
+  ip->ip_ttl = MAXTTL;
+  { /* swap */
+    struct in_addr icmp_dst;
+    icmp_dst = ip->ip_dst;
+    ip->ip_dst = ip->ip_src;
+    ip->ip_src = icmp_dst;
+  }
+
+  (void ) ip_output((struct socket *)NULL, m);
+}
+
+void icmp_receive(struct socket *so)
+{
+    struct mbuf *m = so->so_m;
+    struct ip *ip = mtod(m, struct ip *);
+    int hlen = ip->ip_hl << 2;
+    u_char error_code;
+    struct icmp *icp;
+    int id, len;
+
+    m->m_data += hlen;
+    m->m_len -= hlen;
+    icp = mtod(m, struct icmp *);
+
+    id = icp->icmp_id;
+    len = qemu_recv(so->s, icp, m->m_len, 0);
+    icp->icmp_id = id;
+
+    m->m_data -= hlen;
+    m->m_len += hlen;
+
+    if (len == -1 || len == 0) {
+        if (errno == ENETUNREACH) {
+            error_code = ICMP_UNREACH_NET;
+        } else {
+            error_code = ICMP_UNREACH_HOST;
+        }
+        DEBUG_MISC((dfd, " udp icmp rx errno = %d-%s\n", errno,
+                    strerror(errno)));
+        icmp_error(so->so_m, ICMP_UNREACH, error_code, 0, strerror(errno));
+    } else {
+        icmp_reflect(so->so_m);
+        so->so_m = NULL; /* Don't m_free() it again! */
+    }
+    icmp_detach(so);
+}
diff --git a/src/slirp/ip_icmp.h b/src/slirp/ip_icmp.h
new file mode 100644
index 0000000..be4426b
--- /dev/null
+++ b/src/slirp/ip_icmp.h
@@ -0,0 +1,165 @@
+/*
+ * Copyright (c) 1982, 1986, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)ip_icmp.h	8.1 (Berkeley) 6/10/93
+ * ip_icmp.h,v 1.4 1995/05/30 08:09:43 rgrimes Exp
+ */
+
+#ifndef _NETINET_IP_ICMP_H_
+#define _NETINET_IP_ICMP_H_
+
+/*
+ * Interface Control Message Protocol Definitions.
+ * Per RFC 792, September 1981.
+ */
+
+typedef uint32_t n_time;
+
+/*
+ * Structure of an icmp header.
+ */
+struct icmp {
+	u_char	icmp_type;		/* type of message, see below */
+	u_char	icmp_code;		/* type sub code */
+	u_short	icmp_cksum;		/* ones complement cksum of struct */
+	union {
+		u_char ih_pptr;			/* ICMP_PARAMPROB */
+		struct in_addr ih_gwaddr;	/* ICMP_REDIRECT */
+		struct ih_idseq {
+			u_short	icd_id;
+			u_short	icd_seq;
+		} ih_idseq;
+		int ih_void;
+
+		/* ICMP_UNREACH_NEEDFRAG -- Path MTU Discovery (RFC1191) */
+		struct ih_pmtu {
+			u_short ipm_void;
+			u_short ipm_nextmtu;
+		} ih_pmtu;
+	} icmp_hun;
+#define	icmp_pptr	icmp_hun.ih_pptr
+#define	icmp_gwaddr	icmp_hun.ih_gwaddr
+#define	icmp_id		icmp_hun.ih_idseq.icd_id
+#define	icmp_seq	icmp_hun.ih_idseq.icd_seq
+#define	icmp_void	icmp_hun.ih_void
+#define	icmp_pmvoid	icmp_hun.ih_pmtu.ipm_void
+#define	icmp_nextmtu	icmp_hun.ih_pmtu.ipm_nextmtu
+	union {
+		struct id_ts {
+			n_time its_otime;
+			n_time its_rtime;
+			n_time its_ttime;
+		} id_ts;
+		struct id_ip  {
+			struct ip idi_ip;
+			/* options and then 64 bits of data */
+		} id_ip;
+		uint32_t	id_mask;
+		char		id_data[1];
+	} icmp_dun;
+#define	icmp_otime	icmp_dun.id_ts.its_otime
+#define	icmp_rtime	icmp_dun.id_ts.its_rtime
+#define	icmp_ttime	icmp_dun.id_ts.its_ttime
+#define	icmp_ip		icmp_dun.id_ip.idi_ip
+#define	icmp_mask	icmp_dun.id_mask
+#define	icmp_data	icmp_dun.id_data
+};
+
+/*
+ * Lower bounds on packet lengths for various types.
+ * For the error advice packets must first ensure that the
+ * packet is large enough to contain the returned ip header.
+ * Only then can we do the check to see if 64 bits of packet
+ * data have been returned, since we need to check the returned
+ * ip header length.
+ */
+#define	ICMP_MINLEN	8				/* abs minimum */
+#define	ICMP_TSLEN	(8 + 3 * sizeof (n_time))	/* timestamp */
+#define	ICMP_MASKLEN	12				/* address mask */
+#define	ICMP_ADVLENMIN	(8 + sizeof (struct ip) + 8)	/* min */
+#define	ICMP_ADVLEN(p)	(8 + ((p)->icmp_ip.ip_hl << 2) + 8)
+	/* N.B.: must separately check that ip_hl >= 5 */
+
+/*
+ * Definition of type and code field values.
+ */
+#define	ICMP_ECHOREPLY		0		/* echo reply */
+#define	ICMP_UNREACH		3		/* dest unreachable, codes: */
+#define		ICMP_UNREACH_NET	0		/* bad net */
+#define		ICMP_UNREACH_HOST	1		/* bad host */
+#define		ICMP_UNREACH_PROTOCOL	2		/* bad protocol */
+#define		ICMP_UNREACH_PORT	3		/* bad port */
+#define		ICMP_UNREACH_NEEDFRAG	4		/* IP_DF caused drop */
+#define		ICMP_UNREACH_SRCFAIL	5		/* src route failed */
+#define		ICMP_UNREACH_NET_UNKNOWN 6		/* unknown net */
+#define		ICMP_UNREACH_HOST_UNKNOWN 7		/* unknown host */
+#define		ICMP_UNREACH_ISOLATED	8		/* src host isolated */
+#define		ICMP_UNREACH_NET_PROHIB	9		/* prohibited access */
+#define		ICMP_UNREACH_HOST_PROHIB 10		/* ditto */
+#define		ICMP_UNREACH_TOSNET	11		/* bad tos for net */
+#define		ICMP_UNREACH_TOSHOST	12		/* bad tos for host */
+#define	ICMP_SOURCEQUENCH	4		/* packet lost, slow down */
+#define	ICMP_REDIRECT		5		/* shorter route, codes: */
+#define		ICMP_REDIRECT_NET	0		/* for network */
+#define		ICMP_REDIRECT_HOST	1		/* for host */
+#define		ICMP_REDIRECT_TOSNET	2		/* for tos and net */
+#define		ICMP_REDIRECT_TOSHOST	3		/* for tos and host */
+#define	ICMP_ECHO		8		/* echo service */
+#define	ICMP_ROUTERADVERT	9		/* router advertisement */
+#define	ICMP_ROUTERSOLICIT	10		/* router solicitation */
+#define	ICMP_TIMXCEED		11		/* time exceeded, code: */
+#define		ICMP_TIMXCEED_INTRANS	0		/* ttl==0 in transit */
+#define		ICMP_TIMXCEED_REASS	1		/* ttl==0 in reass */
+#define	ICMP_PARAMPROB		12		/* ip header bad */
+#define		ICMP_PARAMPROB_OPTABSENT 1		/* req. opt. absent */
+#define	ICMP_TSTAMP		13		/* timestamp request */
+#define	ICMP_TSTAMPREPLY	14		/* timestamp reply */
+#define	ICMP_IREQ		15		/* information request */
+#define	ICMP_IREQREPLY		16		/* information reply */
+#define	ICMP_MASKREQ		17		/* address mask request */
+#define	ICMP_MASKREPLY		18		/* address mask reply */
+
+#define	ICMP_MAXTYPE		18
+
+#define	ICMP_INFOTYPE(type) \
+	((type) == ICMP_ECHOREPLY || (type) == ICMP_ECHO || \
+	(type) == ICMP_ROUTERADVERT || (type) == ICMP_ROUTERSOLICIT || \
+	(type) == ICMP_TSTAMP || (type) == ICMP_TSTAMPREPLY || \
+	(type) == ICMP_IREQ || (type) == ICMP_IREQREPLY || \
+	(type) == ICMP_MASKREQ || (type) == ICMP_MASKREPLY)
+
+void icmp_init(Slirp *slirp);
+void icmp_cleanup(Slirp *slirp);
+void icmp_input(struct mbuf *, int);
+void icmp_error(struct mbuf *msrc, u_char type, u_char code, int minsize,
+                const char *message);
+void icmp_reflect(struct mbuf *);
+void icmp_receive(struct socket *so);
+void icmp_detach(struct socket *so);
+
+#endif
diff --git a/src/slirp/ip_input.c b/src/slirp/ip_input.c
new file mode 100644
index 0000000..7d436e6
--- /dev/null
+++ b/src/slirp/ip_input.c
@@ -0,0 +1,668 @@
+/*
+ * Copyright (c) 1982, 1986, 1988, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)ip_input.c	8.2 (Berkeley) 1/4/94
+ * ip_input.c,v 1.11 1994/11/16 10:17:08 jkh Exp
+ */
+
+/*
+ * Changes and additions relating to SLiRP are
+ * Copyright (c) 1995 Danny Gasparovski.
+ *
+ * Please read the file COPYRIGHT for the
+ * terms and conditions of the copyright.
+ */
+
+#include <slirp.h>
+#include <qemu/osdep.h>
+#include "ip_icmp.h"
+
+static struct ip *ip_reass(Slirp *slirp, struct ip *ip, struct ipq *fp);
+static void ip_freef(Slirp *slirp, struct ipq *fp);
+static void ip_enq(register struct ipasfrag *p,
+                   register struct ipasfrag *prev);
+static void ip_deq(register struct ipasfrag *p);
+
+/*
+ * IP initialization: fill in IP protocol switch table.
+ * All protocols not implemented in kernel go to raw IP protocol handler.
+ */
+void
+ip_init(Slirp *slirp)
+{
+    slirp->ipq.ip_link.next = slirp->ipq.ip_link.prev = &slirp->ipq.ip_link;
+    udp_init(slirp);
+    tcp_init(slirp);
+    icmp_init(slirp);
+}
+
+void ip_cleanup(Slirp *slirp)
+{
+    udp_cleanup(slirp);
+    tcp_cleanup(slirp);
+    icmp_cleanup(slirp);
+}
+
+/*
+ * Ip input routine.  Checksum and byte swap header.  If fragmented
+ * try to reassemble.  Process options.  Pass to next level.
+ */
+void
+ip_input(struct mbuf *m)
+{
+	Slirp *slirp = m->slirp;
+	register struct ip *ip;
+	int hlen;
+
+	DEBUG_CALL("ip_input");
+	DEBUG_ARG("m = %p", m);
+	DEBUG_ARG("m_len = %d", m->m_len);
+
+	if (m->m_len < sizeof (struct ip)) {
+		return;
+	}
+
+	ip = mtod(m, struct ip *);
+
+	if (ip->ip_v != IPVERSION) {
+		goto bad;
+	}
+
+	hlen = ip->ip_hl << 2;
+	if (hlen<sizeof(struct ip ) || hlen>m->m_len) {/* min header length */
+	  goto bad;                                  /* or packet too short */
+	}
+
+        /* keep ip header intact for ICMP reply
+	 * ip->ip_sum = cksum(m, hlen);
+	 * if (ip->ip_sum) {
+	 */
+	if(cksum(m,hlen)) {
+	  goto bad;
+	}
+
+	/*
+	 * Convert fields to host representation.
+	 */
+	NTOHS(ip->ip_len);
+	if (ip->ip_len < hlen) {
+		goto bad;
+	}
+	NTOHS(ip->ip_id);
+	NTOHS(ip->ip_off);
+
+	/*
+	 * Check that the amount of data in the buffers
+	 * is as at least much as the IP header would have us expect.
+	 * Trim mbufs if longer than we expect.
+	 * Drop packet if shorter than we expect.
+	 */
+	if (m->m_len < ip->ip_len) {
+		goto bad;
+	}
+
+	/* Should drop packet if mbuf too long? hmmm... */
+	if (m->m_len > ip->ip_len)
+	   m_adj(m, ip->ip_len - m->m_len);
+
+	/* check ip_ttl for a correct ICMP reply */
+	if(ip->ip_ttl==0) {
+	  icmp_error(m, ICMP_TIMXCEED,ICMP_TIMXCEED_INTRANS, 0,"ttl");
+	  goto bad;
+	}
+
+	/*
+	 * If offset or IP_MF are set, must reassemble.
+	 * Otherwise, nothing need be done.
+	 * (We could look in the reassembly queue to see
+	 * if the packet was previously fragmented,
+	 * but it's not worth the time; just let them time out.)
+	 *
+	 * XXX This should fail, don't fragment yet
+	 */
+	if (ip->ip_off &~ IP_DF) {
+	  register struct ipq *fp;
+      struct qlink *l;
+		/*
+		 * Look for queue of fragments
+		 * of this datagram.
+		 */
+		for (l = slirp->ipq.ip_link.next; l != &slirp->ipq.ip_link;
+		     l = l->next) {
+            fp = container_of(l, struct ipq, ip_link);
+            if (ip->ip_id == fp->ipq_id &&
+                    ip->ip_src.s_addr == fp->ipq_src.s_addr &&
+                    ip->ip_dst.s_addr == fp->ipq_dst.s_addr &&
+                    ip->ip_p == fp->ipq_p)
+		    goto found;
+        }
+        fp = NULL;
+	found:
+
+		/*
+		 * Adjust ip_len to not reflect header,
+		 * set ip_mff if more fragments are expected,
+		 * convert offset of this to bytes.
+		 */
+		ip->ip_len -= hlen;
+		if (ip->ip_off & IP_MF)
+		  ip->ip_tos |= 1;
+		else
+		  ip->ip_tos &= ~1;
+
+		ip->ip_off <<= 3;
+
+		/*
+		 * If datagram marked as having more fragments
+		 * or if this is not the first fragment,
+		 * attempt reassembly; if it succeeds, proceed.
+		 */
+		if (ip->ip_tos & 1 || ip->ip_off) {
+			ip = ip_reass(slirp, ip, fp);
+                        if (ip == NULL)
+				return;
+			m = dtom(slirp, ip);
+		} else
+			if (fp)
+		   	   ip_freef(slirp, fp);
+
+	} else
+		ip->ip_len -= hlen;
+
+	/*
+	 * Switch out to protocol's input routine.
+	 */
+	switch (ip->ip_p) {
+	 case IPPROTO_TCP:
+		tcp_input(m, hlen, (struct socket *)NULL);
+		break;
+	 case IPPROTO_UDP:
+		udp_input(m, hlen);
+		break;
+	 case IPPROTO_ICMP:
+		icmp_input(m, hlen);
+		break;
+	 default:
+		m_free(m);
+	}
+	return;
+bad:
+	m_free(m);
+}
+
+#define iptofrag(P) ((struct ipasfrag *)(((char*)(P)) - sizeof(struct qlink)))
+#define fragtoip(P) ((struct ip*)(((char*)(P)) + sizeof(struct qlink)))
+/*
+ * Take incoming datagram fragment and try to
+ * reassemble it into whole datagram.  If a chain for
+ * reassembly of this datagram already exists, then it
+ * is given as fp; otherwise have to make a chain.
+ */
+static struct ip *
+ip_reass(Slirp *slirp, struct ip *ip, struct ipq *fp)
+{
+	register struct mbuf *m = dtom(slirp, ip);
+	register struct ipasfrag *q;
+	int hlen = ip->ip_hl << 2;
+	int i, next;
+
+	DEBUG_CALL("ip_reass");
+	DEBUG_ARG("ip = %p", ip);
+	DEBUG_ARG("fp = %p", fp);
+	DEBUG_ARG("m = %p", m);
+
+	/*
+	 * Presence of header sizes in mbufs
+	 * would confuse code below.
+         * Fragment m_data is concatenated.
+	 */
+	m->m_data += hlen;
+	m->m_len -= hlen;
+
+	/*
+	 * If first fragment to arrive, create a reassembly queue.
+	 */
+        if (fp == NULL) {
+	  struct mbuf *t = m_get(slirp);
+
+	  if (t == NULL) {
+	      goto dropfrag;
+	  }
+	  fp = mtod(t, struct ipq *);
+	  insque(&fp->ip_link, &slirp->ipq.ip_link);
+	  fp->ipq_ttl = IPFRAGTTL;
+	  fp->ipq_p = ip->ip_p;
+	  fp->ipq_id = ip->ip_id;
+	  fp->frag_link.next = fp->frag_link.prev = &fp->frag_link;
+	  fp->ipq_src = ip->ip_src;
+	  fp->ipq_dst = ip->ip_dst;
+	  q = (struct ipasfrag *)fp;
+	  goto insert;
+	}
+
+	/*
+	 * Find a segment which begins after this one does.
+	 */
+	for (q = fp->frag_link.next; q != (struct ipasfrag *)&fp->frag_link;
+            q = q->ipf_next)
+		if (q->ipf_off > ip->ip_off)
+			break;
+
+	/*
+	 * If there is a preceding segment, it may provide some of
+	 * our data already.  If so, drop the data from the incoming
+	 * segment.  If it provides all of our data, drop us.
+	 */
+	if (q->ipf_prev != &fp->frag_link) {
+        struct ipasfrag *pq = q->ipf_prev;
+		i = pq->ipf_off + pq->ipf_len - ip->ip_off;
+		if (i > 0) {
+			if (i >= ip->ip_len)
+				goto dropfrag;
+			m_adj(dtom(slirp, ip), i);
+			ip->ip_off += i;
+			ip->ip_len -= i;
+		}
+	}
+
+	/*
+	 * While we overlap succeeding segments trim them or,
+	 * if they are completely covered, dequeue them.
+	 */
+	while (q != (struct ipasfrag*)&fp->frag_link &&
+            ip->ip_off + ip->ip_len > q->ipf_off) {
+		i = (ip->ip_off + ip->ip_len) - q->ipf_off;
+		if (i < q->ipf_len) {
+			q->ipf_len -= i;
+			q->ipf_off += i;
+			m_adj(dtom(slirp, q), i);
+			break;
+		}
+		q = q->ipf_next;
+		m_free(dtom(slirp, q->ipf_prev));
+		ip_deq(q->ipf_prev);
+	}
+
+insert:
+	/*
+	 * Stick new segment in its place;
+	 * check for complete reassembly.
+	 */
+	ip_enq(iptofrag(ip), q->ipf_prev);
+	next = 0;
+	for (q = fp->frag_link.next; q != (struct ipasfrag*)&fp->frag_link;
+            q = q->ipf_next) {
+		if (q->ipf_off != next)
+                        return NULL;
+		next += q->ipf_len;
+	}
+	if (((struct ipasfrag *)(q->ipf_prev))->ipf_tos & 1)
+                return NULL;
+
+	/*
+	 * Reassembly is complete; concatenate fragments.
+	 */
+    q = fp->frag_link.next;
+	m = dtom(slirp, q);
+
+	q = (struct ipasfrag *) q->ipf_next;
+	while (q != (struct ipasfrag*)&fp->frag_link) {
+	  struct mbuf *t = dtom(slirp, q);
+	  q = (struct ipasfrag *) q->ipf_next;
+	  m_cat(m, t);
+	}
+
+	/*
+	 * Create header for new ip packet by
+	 * modifying header of first packet;
+	 * dequeue and discard fragment reassembly header.
+	 * Make header visible.
+	 */
+	q = fp->frag_link.next;
+
+	/*
+	 * If the fragments concatenated to an mbuf that's
+	 * bigger than the total size of the fragment, then and
+	 * m_ext buffer was alloced. But fp->ipq_next points to
+	 * the old buffer (in the mbuf), so we must point ip
+	 * into the new buffer.
+	 */
+	if (m->m_flags & M_EXT) {
+	  int delta = (char *)q - m->m_dat;
+	  q = (struct ipasfrag *)(m->m_ext + delta);
+	}
+
+    ip = fragtoip(q);
+	ip->ip_len = next;
+	ip->ip_tos &= ~1;
+	ip->ip_src = fp->ipq_src;
+	ip->ip_dst = fp->ipq_dst;
+	remque(&fp->ip_link);
+	(void) m_free(dtom(slirp, fp));
+	m->m_len += (ip->ip_hl << 2);
+	m->m_data -= (ip->ip_hl << 2);
+
+	return ip;
+
+dropfrag:
+	m_free(m);
+        return NULL;
+}
+
+/*
+ * Free a fragment reassembly header and all
+ * associated datagrams.
+ */
+static void
+ip_freef(Slirp *slirp, struct ipq *fp)
+{
+	register struct ipasfrag *q, *p;
+
+	for (q = fp->frag_link.next; q != (struct ipasfrag*)&fp->frag_link; q = p) {
+		p = q->ipf_next;
+		ip_deq(q);
+		m_free(dtom(slirp, q));
+	}
+	remque(&fp->ip_link);
+	(void) m_free(dtom(slirp, fp));
+}
+
+/*
+ * Put an ip fragment on a reassembly chain.
+ * Like insque, but pointers in middle of structure.
+ */
+static void
+ip_enq(register struct ipasfrag *p, register struct ipasfrag *prev)
+{
+	DEBUG_CALL("ip_enq");
+	DEBUG_ARG("prev = %p", prev);
+	p->ipf_prev =  prev;
+	p->ipf_next = prev->ipf_next;
+	((struct ipasfrag *)(prev->ipf_next))->ipf_prev = p;
+	prev->ipf_next = p;
+}
+
+/*
+ * To ip_enq as remque is to insque.
+ */
+static void
+ip_deq(register struct ipasfrag *p)
+{
+	((struct ipasfrag *)(p->ipf_prev))->ipf_next = p->ipf_next;
+	((struct ipasfrag *)(p->ipf_next))->ipf_prev = p->ipf_prev;
+}
+
+/*
+ * IP timer processing;
+ * if a timer expires on a reassembly
+ * queue, discard it.
+ */
+void
+ip_slowtimo(Slirp *slirp)
+{
+    struct qlink *l;
+
+	DEBUG_CALL("ip_slowtimo");
+
+    l = slirp->ipq.ip_link.next;
+
+        if (l == NULL)
+	   return;
+
+    while (l != &slirp->ipq.ip_link) {
+        struct ipq *fp = container_of(l, struct ipq, ip_link);
+        l = l->next;
+		if (--fp->ipq_ttl == 0) {
+			ip_freef(slirp, fp);
+		}
+    }
+}
+
+/*
+ * Do option processing on a datagram,
+ * possibly discarding it if bad options are encountered,
+ * or forwarding it if source-routed.
+ * Returns 1 if packet has been forwarded/freed,
+ * 0 if the packet should be processed further.
+ */
+
+#ifdef notdef
+
+int
+ip_dooptions(m)
+	struct mbuf *m;
+{
+	register struct ip *ip = mtod(m, struct ip *);
+	register u_char *cp;
+	register struct ip_timestamp *ipt;
+	register struct in_ifaddr *ia;
+	int opt, optlen, cnt, off, code, type, forward = 0;
+	struct in_addr *sin, dst;
+typedef uint32_t n_time;
+	n_time ntime;
+
+	dst = ip->ip_dst;
+	cp = (u_char *)(ip + 1);
+	cnt = (ip->ip_hl << 2) - sizeof (struct ip);
+	for (; cnt > 0; cnt -= optlen, cp += optlen) {
+		opt = cp[IPOPT_OPTVAL];
+		if (opt == IPOPT_EOL)
+			break;
+		if (opt == IPOPT_NOP)
+			optlen = 1;
+		else {
+			optlen = cp[IPOPT_OLEN];
+			if (optlen <= 0 || optlen > cnt) {
+				code = &cp[IPOPT_OLEN] - (u_char *)ip;
+				goto bad;
+			}
+		}
+		switch (opt) {
+
+		default:
+			break;
+
+		/*
+		 * Source routing with record.
+		 * Find interface with current destination address.
+		 * If none on this machine then drop if strictly routed,
+		 * or do nothing if loosely routed.
+		 * Record interface address and bring up next address
+		 * component.  If strictly routed make sure next
+		 * address is on directly accessible net.
+		 */
+		case IPOPT_LSRR:
+		case IPOPT_SSRR:
+			if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
+				code = &cp[IPOPT_OFFSET] - (u_char *)ip;
+				goto bad;
+			}
+			ipaddr.sin_addr = ip->ip_dst;
+			ia = (struct in_ifaddr *)
+				ifa_ifwithaddr((struct sockaddr *)&ipaddr);
+			if (ia == 0) {
+				if (opt == IPOPT_SSRR) {
+					type = ICMP_UNREACH;
+					code = ICMP_UNREACH_SRCFAIL;
+					goto bad;
+				}
+				/*
+				 * Loose routing, and not at next destination
+				 * yet; nothing to do except forward.
+				 */
+				break;
+			}
+                        off--; /* 0 origin */
+			if (off > optlen - sizeof(struct in_addr)) {
+				/*
+				 * End of source route.  Should be for us.
+				 */
+				save_rte(cp, ip->ip_src);
+				break;
+			}
+			/*
+			 * locate outgoing interface
+			 */
+			bcopy((caddr_t)(cp + off), (caddr_t)&ipaddr.sin_addr,
+			    sizeof(ipaddr.sin_addr));
+			if (opt == IPOPT_SSRR) {
+#define	INA	struct in_ifaddr *
+#define	SA	struct sockaddr *
+ 			    if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == 0)
+				ia = (INA)ifa_ifwithnet((SA)&ipaddr);
+			} else
+				ia = ip_rtaddr(ipaddr.sin_addr);
+			if (ia == 0) {
+				type = ICMP_UNREACH;
+				code = ICMP_UNREACH_SRCFAIL;
+				goto bad;
+			}
+			ip->ip_dst = ipaddr.sin_addr;
+			bcopy((caddr_t)&(IA_SIN(ia)->sin_addr),
+			    (caddr_t)(cp + off), sizeof(struct in_addr));
+			cp[IPOPT_OFFSET] += sizeof(struct in_addr);
+			/*
+			 * Let ip_intr's mcast routing check handle mcast pkts
+			 */
+			forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr));
+			break;
+
+		case IPOPT_RR:
+			if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
+				code = &cp[IPOPT_OFFSET] - (u_char *)ip;
+				goto bad;
+			}
+			/*
+			 * If no space remains, ignore.
+			 */
+                        off--; /* 0 origin */
+			if (off > optlen - sizeof(struct in_addr))
+				break;
+			bcopy((caddr_t)(&ip->ip_dst), (caddr_t)&ipaddr.sin_addr,
+			    sizeof(ipaddr.sin_addr));
+			/*
+			 * locate outgoing interface; if we're the destination,
+			 * use the incoming interface (should be same).
+			 */
+			if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == 0 &&
+			    (ia = ip_rtaddr(ipaddr.sin_addr)) == 0) {
+				type = ICMP_UNREACH;
+				code = ICMP_UNREACH_HOST;
+				goto bad;
+			}
+			bcopy((caddr_t)&(IA_SIN(ia)->sin_addr),
+			    (caddr_t)(cp + off), sizeof(struct in_addr));
+			cp[IPOPT_OFFSET] += sizeof(struct in_addr);
+			break;
+
+		case IPOPT_TS:
+			code = cp - (u_char *)ip;
+			ipt = (struct ip_timestamp *)cp;
+			if (ipt->ipt_len < 5)
+				goto bad;
+			if (ipt->ipt_ptr > ipt->ipt_len - sizeof (int32_t)) {
+				if (++ipt->ipt_oflw == 0)
+					goto bad;
+				break;
+			}
+			sin = (struct in_addr *)(cp + ipt->ipt_ptr - 1);
+			switch (ipt->ipt_flg) {
+
+			case IPOPT_TS_TSONLY:
+				break;
+
+			case IPOPT_TS_TSANDADDR:
+				if (ipt->ipt_ptr + sizeof(n_time) +
+				    sizeof(struct in_addr) > ipt->ipt_len)
+					goto bad;
+				ipaddr.sin_addr = dst;
+				ia = (INA)ifaof_ i f p foraddr((SA)&ipaddr,
+							    m->m_pkthdr.rcvif);
+				if (ia == 0)
+					continue;
+				bcopy((caddr_t)&IA_SIN(ia)->sin_addr,
+				    (caddr_t)sin, sizeof(struct in_addr));
+				ipt->ipt_ptr += sizeof(struct in_addr);
+				break;
+
+			case IPOPT_TS_PRESPEC:
+				if (ipt->ipt_ptr + sizeof(n_time) +
+				    sizeof(struct in_addr) > ipt->ipt_len)
+					goto bad;
+				bcopy((caddr_t)sin, (caddr_t)&ipaddr.sin_addr,
+				    sizeof(struct in_addr));
+				if (ifa_ifwithaddr((SA)&ipaddr) == 0)
+					continue;
+				ipt->ipt_ptr += sizeof(struct in_addr);
+				break;
+
+			default:
+				goto bad;
+			}
+			ntime = iptime();
+			bcopy((caddr_t)&ntime, (caddr_t)cp + ipt->ipt_ptr - 1,
+			    sizeof(n_time));
+			ipt->ipt_ptr += sizeof(n_time);
+		}
+	}
+	if (forward) {
+		ip_forward(m, 1);
+		return (1);
+	}
+	return (0);
+bad:
+ 	icmp_error(m, type, code, 0, 0);
+
+	return (1);
+}
+
+#endif /* notdef */
+
+/*
+ * Strip out IP options, at higher
+ * level protocol in the kernel.
+ * Second argument is buffer to which options
+ * will be moved, and return value is their length.
+ * (XXX) should be deleted; last arg currently ignored.
+ */
+void
+ip_stripoptions(register struct mbuf *m, struct mbuf *mopt)
+{
+	register int i;
+	struct ip *ip = mtod(m, struct ip *);
+	register caddr_t opts;
+	int olen;
+
+	olen = (ip->ip_hl<<2) - sizeof (struct ip);
+	opts = (caddr_t)(ip + 1);
+	i = m->m_len - (sizeof (struct ip) + olen);
+	memcpy(opts, opts  + olen, (unsigned)i);
+	m->m_len -= olen;
+
+	ip->ip_hl = sizeof(struct ip) >> 2;
+}
diff --git a/src/slirp/ip_output.c b/src/slirp/ip_output.c
new file mode 100644
index 0000000..1254d0d
--- /dev/null
+++ b/src/slirp/ip_output.c
@@ -0,0 +1,172 @@
+/*
+ * Copyright (c) 1982, 1986, 1988, 1990, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)ip_output.c	8.3 (Berkeley) 1/21/94
+ * ip_output.c,v 1.9 1994/11/16 10:17:10 jkh Exp
+ */
+
+/*
+ * Changes and additions relating to SLiRP are
+ * Copyright (c) 1995 Danny Gasparovski.
+ *
+ * Please read the file COPYRIGHT for the
+ * terms and conditions of the copyright.
+ */
+
+#include <slirp.h>
+
+/* Number of packets queued before we start sending
+ * (to prevent allocing too many mbufs) */
+#define IF_THRESH 10
+
+/*
+ * IP output.  The packet in mbuf chain m contains a skeletal IP
+ * header (with len, off, ttl, proto, tos, src, dst).
+ * The mbuf chain containing the packet will be freed.
+ * The mbuf opt, if present, will not be freed.
+ */
+int
+ip_output(struct socket *so, struct mbuf *m0)
+{
+	Slirp *slirp = m0->slirp;
+	register struct ip *ip;
+	register struct mbuf *m = m0;
+	register int hlen = sizeof(struct ip );
+	int len, off, error = 0;
+
+	DEBUG_CALL("ip_output");
+	DEBUG_ARG("so = %p", so);
+	DEBUG_ARG("m0 = %p", m0);
+
+	ip = mtod(m, struct ip *);
+	/*
+	 * Fill in IP header.
+	 */
+	ip->ip_v = IPVERSION;
+	ip->ip_off &= IP_DF;
+	ip->ip_id = htons(slirp->ip_id++);
+	ip->ip_hl = hlen >> 2;
+
+	/*
+	 * If small enough for interface, can just send directly.
+	 */
+	if ((uint16_t)ip->ip_len <= IF_MTU) {
+		ip->ip_len = htons((uint16_t)ip->ip_len);
+		ip->ip_off = htons((uint16_t)ip->ip_off);
+		ip->ip_sum = 0;
+		ip->ip_sum = cksum(m, hlen);
+
+		if_output(so, m);
+		goto done;
+	}
+
+	/*
+	 * Too large for interface; fragment if possible.
+	 * Must be able to put at least 8 bytes per fragment.
+	 */
+	if (ip->ip_off & IP_DF) {
+		error = -1;
+		goto bad;
+	}
+
+	len = (IF_MTU - hlen) &~ 7;       /* ip databytes per packet */
+	if (len < 8) {
+		error = -1;
+		goto bad;
+	}
+
+    {
+	int mhlen, firstlen = len;
+	struct mbuf **mnext = &m->m_nextpkt;
+
+	/*
+	 * Loop through length of segment after first fragment,
+	 * make new header and copy data of each part and link onto chain.
+	 */
+	m0 = m;
+	mhlen = sizeof (struct ip);
+	for (off = hlen + len; off < (uint16_t)ip->ip_len; off += len) {
+	  register struct ip *mhip;
+	  m = m_get(slirp);
+          if (m == NULL) {
+	    error = -1;
+	    goto sendorfree;
+	  }
+	  m->m_data += IF_MAXLINKHDR;
+	  mhip = mtod(m, struct ip *);
+	  *mhip = *ip;
+
+	  m->m_len = mhlen;
+	  mhip->ip_off = ((off - hlen) >> 3) + (ip->ip_off & ~IP_MF);
+	  if (ip->ip_off & IP_MF)
+	    mhip->ip_off |= IP_MF;
+	  if (off + len >= (uint16_t)ip->ip_len)
+	    len = (uint16_t)ip->ip_len - off;
+	  else
+	    mhip->ip_off |= IP_MF;
+	  mhip->ip_len = htons((uint16_t)(len + mhlen));
+
+	  if (m_copy(m, m0, off, len) < 0) {
+	    error = -1;
+	    goto sendorfree;
+	  }
+
+	  mhip->ip_off = htons((uint16_t)mhip->ip_off);
+	  mhip->ip_sum = 0;
+	  mhip->ip_sum = cksum(m, mhlen);
+	  *mnext = m;
+	  mnext = &m->m_nextpkt;
+	}
+	/*
+	 * Update first fragment by trimming what's been copied out
+	 * and updating header, then send each fragment (in order).
+	 */
+	m = m0;
+	m_adj(m, hlen + firstlen - (uint16_t)ip->ip_len);
+	ip->ip_len = htons((uint16_t)m->m_len);
+	ip->ip_off = htons((uint16_t)(ip->ip_off | IP_MF));
+	ip->ip_sum = 0;
+	ip->ip_sum = cksum(m, hlen);
+sendorfree:
+	for (m = m0; m; m = m0) {
+		m0 = m->m_nextpkt;
+                m->m_nextpkt = NULL;
+		if (error == 0)
+			if_output(so, m);
+		else
+			m_free(m);
+	}
+    }
+
+done:
+	return (error);
+
+bad:
+	m_free(m0);
+	goto done;
+}
diff --git a/src/slirp/libslirp.h b/src/slirp/libslirp.h
new file mode 100644
index 0000000..5bdcbd5
--- /dev/null
+++ b/src/slirp/libslirp.h
@@ -0,0 +1,43 @@
+#ifndef _LIBSLIRP_H
+#define _LIBSLIRP_H
+
+#include "qemu-common.h"
+
+struct Slirp;
+typedef struct Slirp Slirp;
+
+int get_dns_addr(struct in_addr *pdns_addr);
+
+Slirp *slirp_init(int restricted, struct in_addr vnetwork,
+                  struct in_addr vnetmask, struct in_addr vhost,
+                  const char *vhostname, const char *tftp_path,
+                  const char *bootfile, struct in_addr vdhcp_start,
+                  struct in_addr vnameserver, const char **vdnssearch,
+                  void *opaque);
+void slirp_cleanup(Slirp *slirp);
+
+void slirp_pollfds_fill(GArray *pollfds, uint32_t *timeout);
+
+void slirp_pollfds_poll(GArray *pollfds, int select_error);
+
+void slirp_input(Slirp *slirp, const uint8_t *pkt, int pkt_len);
+
+/* you must provide the following functions: */
+void slirp_output(void *opaque, const uint8_t *pkt, int pkt_len);
+
+int slirp_add_hostfwd(Slirp *slirp, int is_udp,
+                      struct in_addr host_addr, int host_port,
+                      struct in_addr guest_addr, int guest_port);
+int slirp_remove_hostfwd(Slirp *slirp, int is_udp,
+                         struct in_addr host_addr, int host_port);
+int slirp_add_exec(Slirp *slirp, int do_pty, const void *args,
+                   struct in_addr *guest_addr, int guest_port);
+
+void slirp_connection_info(Slirp *slirp, Monitor *mon);
+
+void slirp_socket_recv(Slirp *slirp, struct in_addr guest_addr,
+                       int guest_port, const uint8_t *buf, int size);
+size_t slirp_socket_can_recv(Slirp *slirp, struct in_addr guest_addr,
+                             int guest_port);
+
+#endif
diff --git a/src/slirp/main.h b/src/slirp/main.h
new file mode 100644
index 0000000..f2e58cf
--- /dev/null
+++ b/src/slirp/main.h
@@ -0,0 +1,50 @@
+/*
+ * Copyright (c) 1995 Danny Gasparovski.
+ *
+ * Please read the file COPYRIGHT for the
+ * terms and conditions of the copyright.
+ */
+#ifndef SLIRP_MAIN_H
+#define SLIRP_MAIN_H 1
+
+#ifdef HAVE_SYS_SELECT_H
+#include <sys/select.h>
+#endif
+
+#define TOWRITEMAX 512
+
+extern int slirp_socket;
+extern int slirp_socket_unit;
+extern int slirp_socket_port;
+extern uint32_t slirp_socket_addr;
+extern char *slirp_socket_passwd;
+extern int ctty_closed;
+
+/*
+ * Get the difference in 2 times from updtim()
+ * Allow for wraparound times, "just in case"
+ * x is the greater of the 2 (current time) and y is
+ * what it's being compared against.
+ */
+#define TIME_DIFF(x,y) (x)-(y) < 0 ? ~0-(y)+(x) : (x)-(y)
+
+extern char *slirp_tty;
+extern char *exec_shell;
+extern u_int curtime;
+extern struct in_addr loopback_addr;
+extern unsigned long loopback_mask;
+extern char *username;
+extern char *socket_path;
+extern int towrite_max;
+extern int ppp_exit;
+extern int tcp_keepintvl;
+
+#define PROTO_SLIP 0x1
+#ifdef USE_PPP
+#define PROTO_PPP 0x2
+#endif
+
+int if_encap(Slirp *slirp, struct mbuf *ifm);
+ssize_t slirp_send(struct socket *so, const void *buf, size_t len, int flags);
+
+#endif
diff --git a/src/slirp/mbuf.c b/src/slirp/mbuf.c
new file mode 100644
index 0000000..795fc29
--- /dev/null
+++ b/src/slirp/mbuf.c
@@ -0,0 +1,241 @@
+/*
+ * Copyright (c) 1995 Danny Gasparovski
+ *
+ * Please read the file COPYRIGHT for the
+ * terms and conditions of the copyright.
+ */
+
+/*
+ * mbuf's in SLiRP are much simpler than the real mbufs in
+ * FreeBSD.  They are fixed size, determined by the MTU,
+ * so that one whole packet can fit.  Mbuf's cannot be
+ * chained together.  If there's more data than the mbuf
+ * could hold, an external malloced buffer is pointed to
+ * by m_ext (and the data pointers) and M_EXT is set in
+ * the flags
+ */
+
+#include <slirp.h>
+
+#define MBUF_THRESH 30
+
+/*
+ * Find a nice value for msize
+ * XXX if_maxlinkhdr already in mtu
+ */
+#define SLIRP_MSIZE (IF_MTU + IF_MAXLINKHDR + offsetof(struct mbuf, m_dat) + 6)
+
+void
+m_init(Slirp *slirp)
+{
+    slirp->m_freelist.m_next = slirp->m_freelist.m_prev = &slirp->m_freelist;
+    slirp->m_usedlist.m_next = slirp->m_usedlist.m_prev = &slirp->m_usedlist;
+}
+
+void m_cleanup(Slirp *slirp)
+{
+    struct mbuf *m, *next;
+
+    m = slirp->m_usedlist.m_next;
+    while (m != &slirp->m_usedlist) {
+        next = m->m_next;
+        if (m->m_flags & M_EXT) {
+            free(m->m_ext);
+        }
+        free(m);
+        m = next;
+    }
+    m = slirp->m_freelist.m_next;
+    while (m != &slirp->m_freelist) {
+        next = m->m_next;
+        free(m);
+        m = next;
+    }
+}
+
+/*
+ * Get an mbuf from the free list, if there are none
+ * malloc one
+ *
+ * Because fragmentation can occur if we alloc new mbufs and
+ * free old mbufs, we mark all mbufs above mbuf_thresh as M_DOFREE,
+ * which tells m_free to actually free() it
+ */
+struct mbuf *
+m_get(Slirp *slirp)
+{
+	register struct mbuf *m;
+	int flags = 0;
+
+	DEBUG_CALL("m_get");
+
+	if (slirp->m_freelist.m_next == &slirp->m_freelist) {
+		m = (struct mbuf *)malloc(SLIRP_MSIZE);
+		if (m == NULL) goto end_error;
+		slirp->mbuf_alloced++;
+		if (slirp->mbuf_alloced > MBUF_THRESH)
+			flags = M_DOFREE;
+		m->slirp = slirp;
+	} else {
+		m = slirp->m_freelist.m_next;
+		remque(m);
+	}
+
+	/* Insert it in the used list */
+	insque(m,&slirp->m_usedlist);
+	m->m_flags = (flags | M_USEDLIST);
+
+	/* Initialise it */
+	m->m_size = SLIRP_MSIZE - offsetof(struct mbuf, m_dat);
+	m->m_data = m->m_dat;
+	m->m_len = 0;
+        m->m_nextpkt = NULL;
+        m->m_prevpkt = NULL;
+        m->arp_requested = false;
+        m->expiration_date = (uint64_t)-1;
+end_error:
+	DEBUG_ARG("m = %p", m);
+	return m;
+}
+
+void
+m_free(struct mbuf *m)
+{
+
+  DEBUG_CALL("m_free");
+  DEBUG_ARG("m = %p", m);
+
+  if(m) {
+	/* Remove from m_usedlist */
+	if (m->m_flags & M_USEDLIST)
+	   remque(m);
+
+	/* If it's M_EXT, free() it */
+	if (m->m_flags & M_EXT)
+	   free(m->m_ext);
+
+	/*
+	 * Either free() it or put it on the free list
+	 */
+	if (m->m_flags & M_DOFREE) {
+		m->slirp->mbuf_alloced--;
+		free(m);
+	} else if ((m->m_flags & M_FREELIST) == 0) {
+		insque(m,&m->slirp->m_freelist);
+		m->m_flags = M_FREELIST; /* Clobber other flags */
+	}
+  } /* if(m) */
+}
+
+/*
+ * Copy data from one mbuf to the end of
+ * the other.. if result is too big for one mbuf, malloc()
+ * an M_EXT data segment
+ */
+void
+m_cat(struct mbuf *m, struct mbuf *n)
+{
+	/*
+	 * If there's no room, realloc
+	 */
+	if (M_FREEROOM(m) < n->m_len)
+		m_inc(m,m->m_size+MINCSIZE);
+
+	memcpy(m->m_data+m->m_len, n->m_data, n->m_len);
+	m->m_len += n->m_len;
+
+	m_free(n);
+}
+
+
+/* make m size bytes large */
+void
+m_inc(struct mbuf *m, int size)
+{
+	int datasize;
+
+	/* some compiles throw up on gotos.  This one we can fake. */
+        if(m->m_size>size) return;
+
+        if (m->m_flags & M_EXT) {
+	  datasize = m->m_data - m->m_ext;
+	  m->m_ext = (char *)realloc(m->m_ext,size);
+	  m->m_data = m->m_ext + datasize;
+        } else {
+	  char *dat;
+	  datasize = m->m_data - m->m_dat;
+	  dat = (char *)malloc(size);
+	  memcpy(dat, m->m_dat, m->m_size);
+
+	  m->m_ext = dat;
+	  m->m_data = m->m_ext + datasize;
+	  m->m_flags |= M_EXT;
+        }
+
+        m->m_size = size;
+
+}
+
+
+
+void
+m_adj(struct mbuf *m, int len)
+{
+	if (m == NULL)
+		return;
+	if (len >= 0) {
+		/* Trim from head */
+		m->m_data += len;
+		m->m_len -= len;
+	} else {
+		/* Trim from tail */
+		len = -len;
+		m->m_len -= len;
+	}
+}
+
+
+/*
+ * Copy len bytes from m, starting off bytes into n
+ */
+int
+m_copy(struct mbuf *n, struct mbuf *m, int off, int len)
+{
+	if (len > M_FREEROOM(n))
+		return -1;
+
+	memcpy((n->m_data + n->m_len), (m->m_data + off), len);
+	n->m_len += len;
+	return 0;
+}
+
+
+/*
+ * Given a pointer into an mbuf, return the mbuf
+ * XXX This is a kludge, I should eliminate the need for it
+ * Fortunately, it's not used often
+ */
+struct mbuf *
+dtom(Slirp *slirp, void *dat)
+{
+	struct mbuf *m;
+
+	DEBUG_CALL("dtom");
+	DEBUG_ARG("dat = %p", dat);
+
+	/* bug corrected for M_EXT buffers */
+	for (m = slirp->m_usedlist.m_next; m != &slirp->m_usedlist;
+	     m = m->m_next) {
+	  if (m->m_flags & M_EXT) {
+	    if( (char *)dat>=m->m_ext && (char *)dat<(m->m_ext + m->m_size) )
+	      return m;
+	  } else {
+	    if( (char *)dat >= m->m_dat && (char *)dat<(m->m_dat + m->m_size) )
+	      return m;
+	  }
+	}
+
+	DEBUG_ERROR((dfd, "dtom failed"));
+
+	return (struct mbuf *)0;
+}
diff --git a/src/slirp/mbuf.h b/src/slirp/mbuf.h
new file mode 100644
index 0000000..b144f1c
--- /dev/null
+++ b/src/slirp/mbuf.h
@@ -0,0 +1,118 @@
+/*
+ * Copyright (c) 1982, 1986, 1988, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)mbuf.h	8.3 (Berkeley) 1/21/94
+ * mbuf.h,v 1.9 1994/11/14 13:54:20 bde Exp
+ */
+
+#ifndef _MBUF_H_
+#define _MBUF_H_
+
+#define MINCSIZE 4096	/* Amount to increase mbuf if too small */
+
+/*
+ * Macros for type conversion
+ * mtod(m,t) -	convert mbuf pointer to data pointer of correct type
+ */
+#define mtod(m,t)	((t)(m)->m_data)
+
+/* XXX About mbufs for slirp:
+ * Only one mbuf is ever used in a chain, for each "cell" of data.
+ * m_nextpkt points to the next packet, if fragmented.
+ * If the data is too large, the M_EXT is used, and a larger block
+ * is alloced.  Therefore, m_free[m] must check for M_EXT and if set
+ * free the m_ext.  This is inefficient memory-wise, but who cares.
+ */
+
+/*
+ * How much room is in the mbuf, from m_data to the end of the mbuf
+ */
+#define M_ROOM(m) ((m->m_flags & M_EXT)? \
+			(((m)->m_ext + (m)->m_size) - (m)->m_data) \
+		   : \
+			(((m)->m_dat + (m)->m_size) - (m)->m_data))
+
+/*
+ * How much free room there is
+ */
+#define M_FREEROOM(m) (M_ROOM(m) - (m)->m_len)
+#define M_TRAILINGSPACE M_FREEROOM
+
+struct mbuf {
+	/* XXX should union some of these! */
+	/* header at beginning of each mbuf: */
+	struct	mbuf *m_next;		/* Linked list of mbufs */
+	struct	mbuf *m_prev;
+	struct	mbuf *m_nextpkt;	/* Next packet in queue/record */
+	struct	mbuf *m_prevpkt;	/* Flags aren't used in the output queue */
+	int	m_flags;		/* Misc flags */
+
+	int	m_size;			/* Size of data */
+	struct	socket *m_so;
+
+	caddr_t	m_data;			/* Location of data */
+	int	m_len;			/* Amount of data in this mbuf */
+
+	Slirp *slirp;
+	bool	arp_requested;
+	uint64_t expiration_date;
+	/* start of dynamic buffer area, must be last element */
+	union {
+		char	m_dat[1]; /* ANSI don't like 0 sized arrays */
+		char	*m_ext;
+	};
+};
+
+#define ifq_prev m_prev
+#define ifq_next m_next
+#define ifs_prev m_prevpkt
+#define ifs_next m_nextpkt
+#define ifq_so m_so
+
+#define M_EXT			0x01	/* m_ext points to more (malloced) data */
+#define M_FREELIST		0x02	/* mbuf is on free list */
+#define M_USEDLIST		0x04	/* XXX mbuf is on used list (for dtom()) */
+#define M_DOFREE		0x08	/* when m_free is called on the mbuf, free()
+					 * it rather than putting it on the free list */
+
+void m_init(Slirp *);
+void m_cleanup(Slirp *slirp);
+struct mbuf * m_get(Slirp *);
+void m_free(struct mbuf *);
+void m_cat(register struct mbuf *, register struct mbuf *);
+void m_inc(struct mbuf *, int);
+void m_adj(struct mbuf *, int);
+int m_copy(struct mbuf *, struct mbuf *, int, int);
+struct mbuf * dtom(Slirp *, void *);
+
+static inline void ifs_init(struct mbuf *ifm)
+{
+    ifm->ifs_next = ifm->ifs_prev = ifm;
+}
+
+#endif
diff --git a/src/slirp/misc.c b/src/slirp/misc.c
new file mode 100644
index 0000000..5497161
--- /dev/null
+++ b/src/slirp/misc.c
@@ -0,0 +1,319 @@
+/*
+ * Copyright (c) 1995 Danny Gasparovski.
+ *
+ * Please read the file COPYRIGHT for the
+ * terms and conditions of the copyright.
+ */
+
+#include <slirp.h>
+#include <libslirp.h>
+
+#include "monitor/monitor.h"
+#include "qemu/error-report.h"
+#include "qemu/main-loop.h"
+
+#ifdef DEBUG
+int slirp_debug = DBG_CALL|DBG_MISC|DBG_ERROR;
+#endif
+
+struct quehead {
+	struct quehead *qh_link;
+	struct quehead *qh_rlink;
+};
+
+inline void
+insque(void *a, void *b)
+{
+	register struct quehead *element = (struct quehead *) a;
+	register struct quehead *head = (struct quehead *) b;
+	element->qh_link = head->qh_link;
+	head->qh_link = (struct quehead *)element;
+	element->qh_rlink = (struct quehead *)head;
+	((struct quehead *)(element->qh_link))->qh_rlink
+	= (struct quehead *)element;
+}
+
+inline void
+remque(void *a)
+{
+  register struct quehead *element = (struct quehead *) a;
+  ((struct quehead *)(element->qh_link))->qh_rlink = element->qh_rlink;
+  ((struct quehead *)(element->qh_rlink))->qh_link = element->qh_link;
+  element->qh_rlink = NULL;
+}
+
+int add_exec(struct ex_list **ex_ptr, int do_pty, char *exec,
+             struct in_addr addr, int port)
+{
+	struct ex_list *tmp_ptr;
+
+	/* First, check if the port is "bound" */
+	for (tmp_ptr = *ex_ptr; tmp_ptr; tmp_ptr = tmp_ptr->ex_next) {
+		if (port == tmp_ptr->ex_fport &&
+		    addr.s_addr == tmp_ptr->ex_addr.s_addr)
+			return -1;
+	}
+
+	tmp_ptr = *ex_ptr;
+	*ex_ptr = g_new(struct ex_list, 1);
+	(*ex_ptr)->ex_fport = port;
+	(*ex_ptr)->ex_addr = addr;
+	(*ex_ptr)->ex_pty = do_pty;
+	(*ex_ptr)->ex_exec = (do_pty == 3) ? exec : g_strdup(exec);
+	(*ex_ptr)->ex_next = tmp_ptr;
+	return 0;
+}
+
+#ifndef HAVE_STRERROR
+
+/*
+ * For systems with no strerror
+ */
+
+extern int sys_nerr;
+extern char *sys_errlist[];
+
+char *
+strerror(error)
+	int error;
+{
+	if (error < sys_nerr)
+	   return sys_errlist[error];
+	else
+	   return "Unknown error.";
+}
+
+#endif
+
+
+#ifdef _WIN32
+
+int
+fork_exec(struct socket *so, const char *ex, int do_pty)
+{
+    /* not implemented */
+    return 0;
+}
+
+#else
+
+/*
+ * XXX This is ugly
+ * We create and bind a socket, then fork off to another
+ * process, which connects to this socket, after which we
+ * exec the wanted program.  If something (strange) happens,
+ * the accept() call could block us forever.
+ *
+ * do_pty = 0   Fork/exec inetd style
+ * do_pty = 1   Fork/exec using slirp.telnetd
+ * do_ptr = 2   Fork/exec using pty
+ */
+int
+fork_exec(struct socket *so, const char *ex, int do_pty)
+{
+	int s;
+	struct sockaddr_in addr;
+	socklen_t addrlen = sizeof(addr);
+	int opt;
+	const char *argv[256];
+	/* don't want to clobber the original */
+	char *bptr;
+	const char *curarg;
+	int c, i, ret;
+	pid_t pid;
+
+	DEBUG_CALL("fork_exec");
+	DEBUG_ARG("so = %p", so);
+	DEBUG_ARG("ex = %p", ex);
+	DEBUG_ARG("do_pty = %x", do_pty);
+
+	if (do_pty == 2) {
+                return 0;
+	} else {
+		addr.sin_family = AF_INET;
+		addr.sin_port = 0;
+		addr.sin_addr.s_addr = INADDR_ANY;
+
+		if ((s = qemu_socket(AF_INET, SOCK_STREAM, 0)) < 0 ||
+		    bind(s, (struct sockaddr *)&addr, addrlen) < 0 ||
+		    listen(s, 1) < 0) {
+			error_report("Error: inet socket: %s", strerror(errno));
+			closesocket(s);
+
+			return 0;
+		}
+	}
+
+	pid = fork();
+	switch(pid) {
+	 case -1:
+		error_report("Error: fork failed: %s", strerror(errno));
+		close(s);
+		return 0;
+
+	 case 0:
+                setsid();
+
+		/* Set the DISPLAY */
+                getsockname(s, (struct sockaddr *)&addr, &addrlen);
+                close(s);
+                /*
+                 * Connect to the socket
+                 * XXX If any of these fail, we're in trouble!
+                 */
+                s = qemu_socket(AF_INET, SOCK_STREAM, 0);
+                addr.sin_addr = loopback_addr;
+                do {
+                    ret = connect(s, (struct sockaddr *)&addr, addrlen);
+                } while (ret < 0 && errno == EINTR);
+
+		dup2(s, 0);
+		dup2(s, 1);
+		dup2(s, 2);
+		for (s = getdtablesize() - 1; s >= 3; s--)
+		   close(s);
+
+		i = 0;
+		bptr = g_strdup(ex); /* No need to free() this */
+		if (do_pty == 1) {
+			/* Setup "slirp.telnetd -x" */
+			argv[i++] = "slirp.telnetd";
+			argv[i++] = "-x";
+			argv[i++] = bptr;
+		} else
+		   do {
+			/* Change the string into argv[] */
+			curarg = bptr;
+			while (*bptr != ' ' && *bptr != (char)0)
+			   bptr++;
+			c = *bptr;
+			*bptr++ = (char)0;
+			argv[i++] = g_strdup(curarg);
+		   } while (c);
+
+                argv[i] = NULL;
+		execvp(argv[0], (char **)argv);
+
+		/* Ooops, failed, let's tell the user why */
+        fprintf(stderr, "Error: execvp of %s failed: %s\n",
+                argv[0], strerror(errno));
+		close(0); close(1); close(2); /* XXX */
+		exit(1);
+
+	 default:
+		qemu_add_child_watch(pid);
+                /*
+                 * XXX this could block us...
+                 * XXX Should set a timer here, and if accept() doesn't
+                 * return after X seconds, declare it a failure
+                 * The only reason this will block forever is if socket()
+                 * of connect() fail in the child process
+                 */
+                do {
+                    so->s = accept(s, (struct sockaddr *)&addr, &addrlen);
+                } while (so->s < 0 && errno == EINTR);
+                closesocket(s);
+                socket_set_fast_reuse(so->s);
+                opt = 1;
+                qemu_setsockopt(so->s, SOL_SOCKET, SO_OOBINLINE, &opt, sizeof(int));
+		qemu_set_nonblock(so->s);
+
+		/* Append the telnet options now */
+                if (so->so_m != NULL && do_pty == 1)  {
+			sbappend(so, so->so_m);
+                        so->so_m = NULL;
+		}
+
+		return 1;
+	}
+}
+#endif
+
+void slirp_connection_info(Slirp *slirp, Monitor *mon)
+{
+    const char * const tcpstates[] = {
+        [TCPS_CLOSED]       = "CLOSED",
+        [TCPS_LISTEN]       = "LISTEN",
+        [TCPS_SYN_SENT]     = "SYN_SENT",
+        [TCPS_SYN_RECEIVED] = "SYN_RCVD",
+        [TCPS_ESTABLISHED]  = "ESTABLISHED",
+        [TCPS_CLOSE_WAIT]   = "CLOSE_WAIT",
+        [TCPS_FIN_WAIT_1]   = "FIN_WAIT_1",
+        [TCPS_CLOSING]      = "CLOSING",
+        [TCPS_LAST_ACK]     = "LAST_ACK",
+        [TCPS_FIN_WAIT_2]   = "FIN_WAIT_2",
+        [TCPS_TIME_WAIT]    = "TIME_WAIT",
+    };
+    struct in_addr dst_addr;
+    struct sockaddr_in src;
+    socklen_t src_len;
+    uint16_t dst_port;
+    struct socket *so;
+    const char *state;
+    char buf[20];
+
+    monitor_printf(mon, "  Protocol[State]    FD  Source Address  Port   "
+                        "Dest. Address  Port RecvQ SendQ\n");
+
+    for (so = slirp->tcb.so_next; so != &slirp->tcb; so = so->so_next) {
+        if (so->so_state & SS_HOSTFWD) {
+            state = "HOST_FORWARD";
+        } else if (so->so_tcpcb) {
+            state = tcpstates[so->so_tcpcb->t_state];
+        } else {
+            state = "NONE";
+        }
+        if (so->so_state & (SS_HOSTFWD | SS_INCOMING)) {
+            src_len = sizeof(src);
+            getsockname(so->s, (struct sockaddr *)&src, &src_len);
+            dst_addr = so->so_laddr;
+            dst_port = so->so_lport;
+        } else {
+            src.sin_addr = so->so_laddr;
+            src.sin_port = so->so_lport;
+            dst_addr = so->so_faddr;
+            dst_port = so->so_fport;
+        }
+        snprintf(buf, sizeof(buf), "  TCP[%s]", state);
+        monitor_printf(mon, "%-19s %3d %15s %5d ", buf, so->s,
+                       src.sin_addr.s_addr ? inet_ntoa(src.sin_addr) : "*",
+                       ntohs(src.sin_port));
+        monitor_printf(mon, "%15s %5d %5d %5d\n",
+                       inet_ntoa(dst_addr), ntohs(dst_port),
+                       so->so_rcv.sb_cc, so->so_snd.sb_cc);
+    }
+
+    for (so = slirp->udb.so_next; so != &slirp->udb; so = so->so_next) {
+        if (so->so_state & SS_HOSTFWD) {
+            snprintf(buf, sizeof(buf), "  UDP[HOST_FORWARD]");
+            src_len = sizeof(src);
+            getsockname(so->s, (struct sockaddr *)&src, &src_len);
+            dst_addr = so->so_laddr;
+            dst_port = so->so_lport;
+        } else {
+            snprintf(buf, sizeof(buf), "  UDP[%d sec]",
+                         (so->so_expire - curtime) / 1000);
+            src.sin_addr = so->so_laddr;
+            src.sin_port = so->so_lport;
+            dst_addr = so->so_faddr;
+            dst_port = so->so_fport;
+        }
+        monitor_printf(mon, "%-19s %3d %15s %5d ", buf, so->s,
+                       src.sin_addr.s_addr ? inet_ntoa(src.sin_addr) : "*",
+                       ntohs(src.sin_port));
+        monitor_printf(mon, "%15s %5d %5d %5d\n",
+                       inet_ntoa(dst_addr), ntohs(dst_port),
+                       so->so_rcv.sb_cc, so->so_snd.sb_cc);
+    }
+
+    for (so = slirp->icmp.so_next; so != &slirp->icmp; so = so->so_next) {
+        snprintf(buf, sizeof(buf), "  ICMP[%d sec]",
+                     (so->so_expire - curtime) / 1000);
+        src.sin_addr = so->so_laddr;
+        dst_addr = so->so_faddr;
+        monitor_printf(mon, "%-19s %3d %15s  -    ", buf, so->s,
+                       src.sin_addr.s_addr ? inet_ntoa(src.sin_addr) : "*");
+        monitor_printf(mon, "%15s  -    %5d %5d\n", inet_ntoa(dst_addr),
+                       so->so_rcv.sb_cc, so->so_snd.sb_cc);
+    }
+}
diff --git a/src/slirp/misc.h b/src/slirp/misc.h
new file mode 100644
index 0000000..41a3258
--- /dev/null
+++ b/src/slirp/misc.h
@@ -0,0 +1,53 @@
+/*
+ * Copyright (c) 1995 Danny Gasparovski.
+ *
+ * Please read the file COPYRIGHT for the
+ * terms and conditions of the copyright.
+ */
+
+#ifndef _MISC_H_
+#define _MISC_H_
+
+struct ex_list {
+	int ex_pty;			/* Do we want a pty? */
+	struct in_addr ex_addr;		/* Server address */
+	int ex_fport;                   /* Port to telnet to */
+	const char *ex_exec;            /* Command line of what to exec */
+	struct ex_list *ex_next;
+};
+
+#define EMU_NONE 0x0
+
+/* TCP emulations */
+#define EMU_CTL 0x1
+#define EMU_FTP 0x2
+#define EMU_KSH 0x3
+#define EMU_IRC 0x4
+#define EMU_REALAUDIO 0x5
+#define EMU_RLOGIN 0x6
+#define EMU_IDENT 0x7
+#define EMU_RSH 0x8
+
+#define EMU_NOCONNECT 0x10	/* Don't connect */
+
+struct tos_t {
+    uint16_t lport;
+    uint16_t fport;
+    uint8_t tos;
+    uint8_t emu;
+};
+
+struct emu_t {
+    uint16_t lport;
+    uint16_t fport;
+    uint8_t tos;
+    uint8_t emu;
+    struct emu_t *next;
+};
+
+void slirp_insque(void *, void *);
+void slirp_remque(void *);
+int add_exec(struct ex_list **, int, char *, struct in_addr, int);
+int fork_exec(struct socket *so, const char *ex, int do_pty);
+
+#endif
diff --git a/src/slirp/sbuf.c b/src/slirp/sbuf.c
new file mode 100644
index 0000000..b8c3db7
--- /dev/null
+++ b/src/slirp/sbuf.c
@@ -0,0 +1,187 @@
+/*
+ * Copyright (c) 1995 Danny Gasparovski.
+ *
+ * Please read the file COPYRIGHT for the
+ * terms and conditions of the copyright.
+ */
+
+#include <slirp.h>
+#include <qemu/main-loop.h>
+
+static void sbappendsb(struct sbuf *sb, struct mbuf *m);
+
+void
+sbfree(struct sbuf *sb)
+{
+	free(sb->sb_data);
+}
+
+void
+sbdrop(struct sbuf *sb, int num)
+{
+    int limit = sb->sb_datalen / 2;
+
+	/*
+	 * We can only drop how much we have
+	 * This should never succeed
+	 */
+	if(num > sb->sb_cc)
+		num = sb->sb_cc;
+	sb->sb_cc -= num;
+	sb->sb_rptr += num;
+	if(sb->sb_rptr >= sb->sb_data + sb->sb_datalen)
+		sb->sb_rptr -= sb->sb_datalen;
+
+    if (sb->sb_cc < limit && sb->sb_cc + num >= limit) {
+        qemu_notify_event();
+    }
+}
+
+void
+sbreserve(struct sbuf *sb, int size)
+{
+	if (sb->sb_data) {
+		/* Already alloced, realloc if necessary */
+		if (sb->sb_datalen != size) {
+			sb->sb_wptr = sb->sb_rptr = sb->sb_data = (char *)realloc(sb->sb_data, size);
+			sb->sb_cc = 0;
+			if (sb->sb_wptr)
+			   sb->sb_datalen = size;
+			else
+			   sb->sb_datalen = 0;
+		}
+	} else {
+		sb->sb_wptr = sb->sb_rptr = sb->sb_data = (char *)malloc(size);
+		sb->sb_cc = 0;
+		if (sb->sb_wptr)
+		   sb->sb_datalen = size;
+		else
+		   sb->sb_datalen = 0;
+	}
+}
+
+/*
+ * Try and write() to the socket, whatever doesn't get written
+ * append to the buffer... for a host with a fast net connection,
+ * this prevents an unnecessary copy of the data
+ * (the socket is non-blocking, so we won't hang)
+ */
+void
+sbappend(struct socket *so, struct mbuf *m)
+{
+	int ret = 0;
+
+	DEBUG_CALL("sbappend");
+	DEBUG_ARG("so = %p", so);
+	DEBUG_ARG("m = %p", m);
+	DEBUG_ARG("m->m_len = %d", m->m_len);
+
+	/* Shouldn't happen, but...  e.g. foreign host closes connection */
+	if (m->m_len <= 0) {
+		m_free(m);
+		return;
+	}
+
+	/*
+	 * If there is urgent data, call sosendoob
+	 * if not all was sent, sowrite will take care of the rest
+	 * (The rest of this function is just an optimisation)
+	 */
+	if (so->so_urgc) {
+		sbappendsb(&so->so_rcv, m);
+		m_free(m);
+		sosendoob(so);
+		return;
+	}
+
+	/*
+	 * We only write if there's nothing in the buffer,
+	 * ottherwise it'll arrive out of order, and hence corrupt
+	 */
+	if (!so->so_rcv.sb_cc)
+	   ret = slirp_send(so, m->m_data, m->m_len, 0);
+
+	if (ret <= 0) {
+		/*
+		 * Nothing was written
+		 * It's possible that the socket has closed, but
+		 * we don't need to check because if it has closed,
+		 * it will be detected in the normal way by soread()
+		 */
+		sbappendsb(&so->so_rcv, m);
+	} else if (ret != m->m_len) {
+		/*
+		 * Something was written, but not everything..
+		 * sbappendsb the rest
+		 */
+		m->m_len -= ret;
+		m->m_data += ret;
+		sbappendsb(&so->so_rcv, m);
+	} /* else */
+	/* Whatever happened, we free the mbuf */
+	m_free(m);
+}
+
+/*
+ * Copy the data from m into sb
+ * The caller is responsible to make sure there's enough room
+ */
+static void
+sbappendsb(struct sbuf *sb, struct mbuf *m)
+{
+	int len, n,  nn;
+
+	len = m->m_len;
+
+	if (sb->sb_wptr < sb->sb_rptr) {
+		n = sb->sb_rptr - sb->sb_wptr;
+		if (n > len) n = len;
+		memcpy(sb->sb_wptr, m->m_data, n);
+	} else {
+		/* Do the right edge first */
+		n = sb->sb_data + sb->sb_datalen - sb->sb_wptr;
+		if (n > len) n = len;
+		memcpy(sb->sb_wptr, m->m_data, n);
+		len -= n;
+		if (len) {
+			/* Now the left edge */
+			nn = sb->sb_rptr - sb->sb_data;
+			if (nn > len) nn = len;
+			memcpy(sb->sb_data,m->m_data+n,nn);
+			n += nn;
+		}
+	}
+
+	sb->sb_cc += n;
+	sb->sb_wptr += n;
+	if (sb->sb_wptr >= sb->sb_data + sb->sb_datalen)
+		sb->sb_wptr -= sb->sb_datalen;
+}
+
+/*
+ * Copy data from sbuf to a normal, straight buffer
+ * Don't update the sbuf rptr, this will be
+ * done in sbdrop when the data is acked
+ */
+void
+sbcopy(struct sbuf *sb, int off, int len, char *to)
+{
+	char *from;
+
+	from = sb->sb_rptr + off;
+	if (from >= sb->sb_data + sb->sb_datalen)
+		from -= sb->sb_datalen;
+
+	if (from < sb->sb_wptr) {
+		if (len > sb->sb_cc) len = sb->sb_cc;
+		memcpy(to,from,len);
+	} else {
+		/* re-use off */
+		off = (sb->sb_data + sb->sb_datalen) - from;
+		if (off > len) off = len;
+		memcpy(to,from,off);
+		len -= off;
+		if (len)
+		   memcpy(to+off,sb->sb_data,len);
+	}
+}
diff --git a/src/slirp/sbuf.h b/src/slirp/sbuf.h
new file mode 100644
index 0000000..4f22e7c
--- /dev/null
+++ b/src/slirp/sbuf.h
@@ -0,0 +1,30 @@
+/*
+ * Copyright (c) 1995 Danny Gasparovski.
+ *
+ * Please read the file COPYRIGHT for the
+ * terms and conditions of the copyright.
+ */
+
+#ifndef _SBUF_H_
+#define _SBUF_H_
+
+#define sbflush(sb) sbdrop((sb),(sb)->sb_cc)
+#define sbspace(sb) ((sb)->sb_datalen - (sb)->sb_cc)
+
+struct sbuf {
+	u_int	sb_cc;		/* actual chars in buffer */
+	u_int	sb_datalen;	/* Length of data  */
+	char	*sb_wptr;	/* write pointer. points to where the next
+				 * bytes should be written in the sbuf */
+	char	*sb_rptr;	/* read pointer. points to where the next
+				 * byte should be read from the sbuf */
+	char	*sb_data;	/* Actual data */
+};
+
+void sbfree(struct sbuf *);
+void sbdrop(struct sbuf *, int);
+void sbreserve(struct sbuf *, int);
+void sbappend(struct socket *, struct mbuf *);
+void sbcopy(struct sbuf *, int, int, char *);
+
+#endif
diff --git a/src/slirp/slirp.c b/src/slirp/slirp.c
new file mode 100644
index 0000000..35f819a
--- /dev/null
+++ b/src/slirp/slirp.c
@@ -0,0 +1,1207 @@
+/*
+ * libslirp glue
+ *
+ * Copyright (c) 2004-2008 Fabrice Bellard
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+#include "qemu-common.h"
+#include "qemu/timer.h"
+#include "sysemu/char.h"
+#include "slirp.h"
+#include "hw/hw.h"
+
+/* host loopback address */
+struct in_addr loopback_addr;
+/* host loopback network mask */
+unsigned long loopback_mask;
+
+/* emulated hosts use the MAC addr 52:55:IP:IP:IP:IP */
+static const uint8_t special_ethaddr[ETH_ALEN] = {
+    0x52, 0x55, 0x00, 0x00, 0x00, 0x00
+};
+
+u_int curtime;
+
+static QTAILQ_HEAD(slirp_instances, Slirp) slirp_instances =
+    QTAILQ_HEAD_INITIALIZER(slirp_instances);
+
+static struct in_addr dns_addr;
+static u_int dns_addr_time;
+
+#define TIMEOUT_FAST 2  /* milliseconds */
+#define TIMEOUT_SLOW 499  /* milliseconds */
+/* for the aging of certain requests like DNS */
+#define TIMEOUT_DEFAULT 1000  /* milliseconds */
+
+#ifdef _WIN32
+
+int get_dns_addr(struct in_addr *pdns_addr)
+{
+    FIXED_INFO *FixedInfo=NULL;
+    ULONG    BufLen;
+    DWORD    ret;
+    IP_ADDR_STRING *pIPAddr;
+    struct in_addr tmp_addr;
+
+    if (dns_addr.s_addr != 0 && (curtime - dns_addr_time) < TIMEOUT_DEFAULT) {
+        *pdns_addr = dns_addr;
+        return 0;
+    }
+
+    FixedInfo = (FIXED_INFO *)GlobalAlloc(GPTR, sizeof(FIXED_INFO));
+    BufLen = sizeof(FIXED_INFO);
+
+    if (ERROR_BUFFER_OVERFLOW == GetNetworkParams(FixedInfo, &BufLen)) {
+        if (FixedInfo) {
+            GlobalFree(FixedInfo);
+            FixedInfo = NULL;
+        }
+        FixedInfo = GlobalAlloc(GPTR, BufLen);
+    }
+
+    if ((ret = GetNetworkParams(FixedInfo, &BufLen)) != ERROR_SUCCESS) {
+        printf("GetNetworkParams failed. ret = %08x\n", (u_int)ret );
+        if (FixedInfo) {
+            GlobalFree(FixedInfo);
+            FixedInfo = NULL;
+        }
+        return -1;
+    }
+
+    pIPAddr = &(FixedInfo->DnsServerList);
+    inet_aton(pIPAddr->IpAddress.String, &tmp_addr);
+    *pdns_addr = tmp_addr;
+    dns_addr = tmp_addr;
+    dns_addr_time = curtime;
+    if (FixedInfo) {
+        GlobalFree(FixedInfo);
+        FixedInfo = NULL;
+    }
+    return 0;
+}
+
+static void winsock_cleanup(void)
+{
+    WSACleanup();
+}
+
+#else
+
+static struct stat dns_addr_stat;
+
+int get_dns_addr(struct in_addr *pdns_addr)
+{
+    char buff[512];
+    char buff2[257];
+    FILE *f;
+    int found = 0;
+    struct in_addr tmp_addr;
+
+    if (dns_addr.s_addr != 0) {
+        struct stat old_stat;
+        if ((curtime - dns_addr_time) < TIMEOUT_DEFAULT) {
+            *pdns_addr = dns_addr;
+            return 0;
+        }
+        old_stat = dns_addr_stat;
+        if (stat("/etc/resolv.conf", &dns_addr_stat) != 0)
+            return -1;
+        if ((dns_addr_stat.st_dev == old_stat.st_dev)
+            && (dns_addr_stat.st_ino == old_stat.st_ino)
+            && (dns_addr_stat.st_size == old_stat.st_size)
+            && (dns_addr_stat.st_mtime == old_stat.st_mtime)) {
+            *pdns_addr = dns_addr;
+            return 0;
+        }
+    }
+
+    f = fopen("/etc/resolv.conf", "r");
+    if (!f)
+        return -1;
+
+#ifdef DEBUG
+    fprintf(stderr, "IP address of your DNS(s): ");
+#endif
+    while (fgets(buff, 512, f) != NULL) {
+        if (sscanf(buff, "nameserver%*[ \t]%256s", buff2) == 1) {
+            if (!inet_aton(buff2, &tmp_addr))
+                continue;
+            /* If it's the first one, set it to dns_addr */
+            if (!found) {
+                *pdns_addr = tmp_addr;
+                dns_addr = tmp_addr;
+                dns_addr_time = curtime;
+            }
+#ifdef DEBUG
+            else
+                fprintf(stderr, ", ");
+#endif
+            if (++found > 3) {
+#ifdef DEBUG
+                fprintf(stderr, "(more)");
+#endif
+                break;
+            }
+#ifdef DEBUG
+            else
+                fprintf(stderr, "%s", inet_ntoa(tmp_addr));
+#endif
+        }
+    }
+    fclose(f);
+    if (!found)
+        return -1;
+    return 0;
+}
+
+#endif
+
+static void slirp_init_once(void)
+{
+    static int initialized;
+#ifdef _WIN32
+    WSADATA Data;
+#endif
+
+    if (initialized) {
+        return;
+    }
+    initialized = 1;
+
+#ifdef _WIN32
+    WSAStartup(MAKEWORD(2,0), &Data);
+    atexit(winsock_cleanup);
+#endif
+
+    loopback_addr.s_addr = htonl(INADDR_LOOPBACK);
+    loopback_mask = htonl(IN_CLASSA_NET);
+}
+
+static void slirp_state_save(QEMUFile *f, void *opaque);
+static int slirp_state_load(QEMUFile *f, void *opaque, int version_id);
+
+Slirp *slirp_init(int restricted, struct in_addr vnetwork,
+                  struct in_addr vnetmask, struct in_addr vhost,
+                  const char *vhostname, const char *tftp_path,
+                  const char *bootfile, struct in_addr vdhcp_start,
+                  struct in_addr vnameserver, const char **vdnssearch,
+                  void *opaque)
+{
+    Slirp *slirp = g_malloc0(sizeof(Slirp));
+
+    slirp_init_once();
+
+    slirp->restricted = restricted;
+
+    if_init(slirp);
+    ip_init(slirp);
+
+    /* Initialise mbufs *after* setting the MTU */
+    m_init(slirp);
+
+    slirp->vnetwork_addr = vnetwork;
+    slirp->vnetwork_mask = vnetmask;
+    slirp->vhost_addr = vhost;
+    if (vhostname) {
+        pstrcpy(slirp->client_hostname, sizeof(slirp->client_hostname),
+                vhostname);
+    }
+    slirp->tftp_prefix = g_strdup(tftp_path);
+    slirp->bootp_filename = g_strdup(bootfile);
+    slirp->vdhcp_startaddr = vdhcp_start;
+    slirp->vnameserver_addr = vnameserver;
+
+    if (vdnssearch) {
+        translate_dnssearch(slirp, vdnssearch);
+    }
+
+    slirp->opaque = opaque;
+
+    register_savevm(NULL, "slirp", 0, 3,
+                    slirp_state_save, slirp_state_load, slirp);
+
+    QTAILQ_INSERT_TAIL(&slirp_instances, slirp, entry);
+
+    return slirp;
+}
+
+void slirp_cleanup(Slirp *slirp)
+{
+    QTAILQ_REMOVE(&slirp_instances, slirp, entry);
+
+    unregister_savevm(NULL, "slirp", slirp);
+
+    ip_cleanup(slirp);
+    m_cleanup(slirp);
+
+    g_free(slirp->vdnssearch);
+    g_free(slirp->tftp_prefix);
+    g_free(slirp->bootp_filename);
+    g_free(slirp);
+}
+
+#define CONN_CANFSEND(so) (((so)->so_state & (SS_FCANTSENDMORE|SS_ISFCONNECTED)) == SS_ISFCONNECTED)
+#define CONN_CANFRCV(so) (((so)->so_state & (SS_FCANTRCVMORE|SS_ISFCONNECTED)) == SS_ISFCONNECTED)
+
+static void slirp_update_timeout(uint32_t *timeout)
+{
+    Slirp *slirp;
+    uint32_t t;
+
+    if (*timeout <= TIMEOUT_FAST) {
+        return;
+    }
+
+    t = MIN(1000, *timeout);
+
+    /* If we have tcp timeout with slirp, then we will fill @timeout with
+     * more precise value.
+     */
+    QTAILQ_FOREACH(slirp, &slirp_instances, entry) {
+        if (slirp->time_fasttimo) {
+            *timeout = TIMEOUT_FAST;
+            return;
+        }
+        if (slirp->do_slowtimo) {
+            t = MIN(TIMEOUT_SLOW, t);
+        }
+    }
+    *timeout = t;
+}
+
+void slirp_pollfds_fill(GArray *pollfds, uint32_t *timeout)
+{
+    Slirp *slirp;
+    struct socket *so, *so_next;
+
+    if (QTAILQ_EMPTY(&slirp_instances)) {
+        return;
+    }
+
+    /*
+     * First, TCP sockets
+     */
+
+    QTAILQ_FOREACH(slirp, &slirp_instances, entry) {
+        /*
+         * *_slowtimo needs calling if there are IP fragments
+         * in the fragment queue, or there are TCP connections active
+         */
+        slirp->do_slowtimo = ((slirp->tcb.so_next != &slirp->tcb) ||
+                (&slirp->ipq.ip_link != slirp->ipq.ip_link.next));
+
+        for (so = slirp->tcb.so_next; so != &slirp->tcb;
+                so = so_next) {
+            int events = 0;
+
+            so_next = so->so_next;
+
+            so->pollfds_idx = -1;
+
+            /*
+             * See if we need a tcp_fasttimo
+             */
+            if (slirp->time_fasttimo == 0 &&
+                so->so_tcpcb->t_flags & TF_DELACK) {
+                slirp->time_fasttimo = curtime; /* Flag when want a fasttimo */
+            }
+
+            /*
+             * NOFDREF can include still connecting to local-host,
+             * newly socreated() sockets etc. Don't want to select these.
+             */
+            if (so->so_state & SS_NOFDREF || so->s == -1) {
+                continue;
+            }
+
+            /*
+             * Set for reading sockets which are accepting
+             */
+            if (so->so_state & SS_FACCEPTCONN) {
+                GPollFD pfd = {
+                    .fd = so->s,
+                    .events = G_IO_IN | G_IO_HUP | G_IO_ERR,
+                };
+                so->pollfds_idx = pollfds->len;
+                g_array_append_val(pollfds, pfd);
+                continue;
+            }
+
+            /*
+             * Set for writing sockets which are connecting
+             */
+            if (so->so_state & SS_ISFCONNECTING) {
+                GPollFD pfd = {
+                    .fd = so->s,
+                    .events = G_IO_OUT | G_IO_ERR,
+                };
+                so->pollfds_idx = pollfds->len;
+                g_array_append_val(pollfds, pfd);
+                continue;
+            }
+
+            /*
+             * Set for writing if we are connected, can send more, and
+             * we have something to send
+             */
+            if (CONN_CANFSEND(so) && so->so_rcv.sb_cc) {
+                events |= G_IO_OUT | G_IO_ERR;
+            }
+
+            /*
+             * Set for reading (and urgent data) if we are connected, can
+             * receive more, and we have room for it XXX /2 ?
+             */
+            if (CONN_CANFRCV(so) &&
+                (so->so_snd.sb_cc < (so->so_snd.sb_datalen/2))) {
+                events |= G_IO_IN | G_IO_HUP | G_IO_ERR | G_IO_PRI;
+            }
+
+            if (events) {
+                GPollFD pfd = {
+                    .fd = so->s,
+                    .events = events,
+                };
+                so->pollfds_idx = pollfds->len;
+                g_array_append_val(pollfds, pfd);
+            }
+        }
+
+        /*
+         * UDP sockets
+         */
+        for (so = slirp->udb.so_next; so != &slirp->udb;
+                so = so_next) {
+            so_next = so->so_next;
+
+            so->pollfds_idx = -1;
+
+            /*
+             * See if it's timed out
+             */
+            if (so->so_expire) {
+                if (so->so_expire <= curtime) {
+                    udp_detach(so);
+                    continue;
+                } else {
+                    slirp->do_slowtimo = true; /* Let socket expire */
+                }
+            }
+
+            /*
+             * When UDP packets are received from over the
+             * link, they're sendto()'d straight away, so
+             * no need for setting for writing
+             * Limit the number of packets queued by this session
+             * to 4.  Note that even though we try and limit this
+             * to 4 packets, the session could have more queued
+             * if the packets needed to be fragmented
+             * (XXX <= 4 ?)
+             */
+            if ((so->so_state & SS_ISFCONNECTED) && so->so_queued <= 4) {
+                GPollFD pfd = {
+                    .fd = so->s,
+                    .events = G_IO_IN | G_IO_HUP | G_IO_ERR,
+                };
+                so->pollfds_idx = pollfds->len;
+                g_array_append_val(pollfds, pfd);
+            }
+        }
+
+        /*
+         * ICMP sockets
+         */
+        for (so = slirp->icmp.so_next; so != &slirp->icmp;
+                so = so_next) {
+            so_next = so->so_next;
+
+            so->pollfds_idx = -1;
+
+            /*
+             * See if it's timed out
+             */
+            if (so->so_expire) {
+                if (so->so_expire <= curtime) {
+                    icmp_detach(so);
+                    continue;
+                } else {
+                    slirp->do_slowtimo = true; /* Let socket expire */
+                }
+            }
+
+            if (so->so_state & SS_ISFCONNECTED) {
+                GPollFD pfd = {
+                    .fd = so->s,
+                    .events = G_IO_IN | G_IO_HUP | G_IO_ERR,
+                };
+                so->pollfds_idx = pollfds->len;
+                g_array_append_val(pollfds, pfd);
+            }
+        }
+    }
+    slirp_update_timeout(timeout);
+}
+
+void slirp_pollfds_poll(GArray *pollfds, int select_error)
+{
+    Slirp *slirp;
+    struct socket *so, *so_next;
+    int ret;
+
+    if (QTAILQ_EMPTY(&slirp_instances)) {
+        return;
+    }
+
+    curtime = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
+
+    QTAILQ_FOREACH(slirp, &slirp_instances, entry) {
+        /*
+         * See if anything has timed out
+         */
+        if (slirp->time_fasttimo &&
+            ((curtime - slirp->time_fasttimo) >= TIMEOUT_FAST)) {
+            tcp_fasttimo(slirp);
+            slirp->time_fasttimo = 0;
+        }
+        if (slirp->do_slowtimo &&
+            ((curtime - slirp->last_slowtimo) >= TIMEOUT_SLOW)) {
+            ip_slowtimo(slirp);
+            tcp_slowtimo(slirp);
+            slirp->last_slowtimo = curtime;
+        }
+
+        /*
+         * Check sockets
+         */
+        if (!select_error) {
+            /*
+             * Check TCP sockets
+             */
+            for (so = slirp->tcb.so_next; so != &slirp->tcb;
+                    so = so_next) {
+                int revents;
+
+                so_next = so->so_next;
+
+                revents = 0;
+                if (so->pollfds_idx != -1) {
+                    revents = g_array_index(pollfds, GPollFD,
+                                            so->pollfds_idx).revents;
+                }
+
+                if (so->so_state & SS_NOFDREF || so->s == -1) {
+                    continue;
+                }
+
+                /*
+                 * Check for URG data
+                 * This will soread as well, so no need to
+                 * test for G_IO_IN below if this succeeds
+                 */
+                if (revents & G_IO_PRI) {
+                    sorecvoob(so);
+                }
+                /*
+                 * Check sockets for reading
+                 */
+                else if (revents & (G_IO_IN | G_IO_HUP | G_IO_ERR)) {
+                    /*
+                     * Check for incoming connections
+                     */
+                    if (so->so_state & SS_FACCEPTCONN) {
+                        tcp_connect(so);
+                        continue;
+                    } /* else */
+                    ret = soread(so);
+
+                    /* Output it if we read something */
+                    if (ret > 0) {
+                        tcp_output(sototcpcb(so));
+                    }
+                }
+
+                /*
+                 * Check sockets for writing
+                 */
+                if (!(so->so_state & SS_NOFDREF) &&
+                        (revents & (G_IO_OUT | G_IO_ERR))) {
+                    /*
+                     * Check for non-blocking, still-connecting sockets
+                     */
+                    if (so->so_state & SS_ISFCONNECTING) {
+                        /* Connected */
+                        so->so_state &= ~SS_ISFCONNECTING;
+
+                        ret = send(so->s, (const void *) &ret, 0, 0);
+                        if (ret < 0) {
+                            /* XXXXX Must fix, zero bytes is a NOP */
+                            if (errno == EAGAIN || errno == EWOULDBLOCK ||
+                                errno == EINPROGRESS || errno == ENOTCONN) {
+                                continue;
+                            }
+
+                            /* else failed */
+                            so->so_state &= SS_PERSISTENT_MASK;
+                            so->so_state |= SS_NOFDREF;
+                        }
+                        /* else so->so_state &= ~SS_ISFCONNECTING; */
+
+                        /*
+                         * Continue tcp_input
+                         */
+                        tcp_input((struct mbuf *)NULL, sizeof(struct ip), so);
+                        /* continue; */
+                    } else {
+                        ret = sowrite(so);
+                    }
+                    /*
+                     * XXXXX If we wrote something (a lot), there
+                     * could be a need for a window update.
+                     * In the worst case, the remote will send
+                     * a window probe to get things going again
+                     */
+                }
+
+                /*
+                 * Probe a still-connecting, non-blocking socket
+                 * to check if it's still alive
+                 */
+#ifdef PROBE_CONN
+                if (so->so_state & SS_ISFCONNECTING) {
+                    ret = qemu_recv(so->s, &ret, 0, 0);
+
+                    if (ret < 0) {
+                        /* XXX */
+                        if (errno == EAGAIN || errno == EWOULDBLOCK ||
+                            errno == EINPROGRESS || errno == ENOTCONN) {
+                            continue; /* Still connecting, continue */
+                        }
+
+                        /* else failed */
+                        so->so_state &= SS_PERSISTENT_MASK;
+                        so->so_state |= SS_NOFDREF;
+
+                        /* tcp_input will take care of it */
+                    } else {
+                        ret = send(so->s, &ret, 0, 0);
+                        if (ret < 0) {
+                            /* XXX */
+                            if (errno == EAGAIN || errno == EWOULDBLOCK ||
+                                errno == EINPROGRESS || errno == ENOTCONN) {
+                                continue;
+                            }
+                            /* else failed */
+                            so->so_state &= SS_PERSISTENT_MASK;
+                            so->so_state |= SS_NOFDREF;
+                        } else {
+                            so->so_state &= ~SS_ISFCONNECTING;
+                        }
+
+                    }
+                    tcp_input((struct mbuf *)NULL, sizeof(struct ip), so);
+                } /* SS_ISFCONNECTING */
+#endif
+            }
+
+            /*
+             * Now UDP sockets.
+             * Incoming packets are sent straight away, they're not buffered.
+             * Incoming UDP data isn't buffered either.
+             */
+            for (so = slirp->udb.so_next; so != &slirp->udb;
+                    so = so_next) {
+                int revents;
+
+                so_next = so->so_next;
+
+                revents = 0;
+                if (so->pollfds_idx != -1) {
+                    revents = g_array_index(pollfds, GPollFD,
+                            so->pollfds_idx).revents;
+                }
+
+                if (so->s != -1 &&
+                    (revents & (G_IO_IN | G_IO_HUP | G_IO_ERR))) {
+                    sorecvfrom(so);
+                }
+            }
+
+            /*
+             * Check incoming ICMP relies.
+             */
+            for (so = slirp->icmp.so_next; so != &slirp->icmp;
+                    so = so_next) {
+                    int revents;
+
+                    so_next = so->so_next;
+
+                    revents = 0;
+                    if (so->pollfds_idx != -1) {
+                        revents = g_array_index(pollfds, GPollFD,
+                                                so->pollfds_idx).revents;
+                    }
+
+                    if (so->s != -1 &&
+                        (revents & (G_IO_IN | G_IO_HUP | G_IO_ERR))) {
+                    icmp_receive(so);
+                }
+            }
+        }
+
+        if_start(slirp);
+    }
+}
+
+static void arp_input(Slirp *slirp, const uint8_t *pkt, int pkt_len)
+{
+    struct arphdr *ah = (struct arphdr *)(pkt + ETH_HLEN);
+    uint8_t arp_reply[max(ETH_HLEN + sizeof(struct arphdr), 64)];
+    struct ethhdr *reh = (struct ethhdr *)arp_reply;
+    struct arphdr *rah = (struct arphdr *)(arp_reply + ETH_HLEN);
+    int ar_op;
+    struct ex_list *ex_ptr;
+
+    ar_op = ntohs(ah->ar_op);
+    switch(ar_op) {
+    case ARPOP_REQUEST:
+        if (ah->ar_tip == ah->ar_sip) {
+            /* Gratuitous ARP */
+            arp_table_add(slirp, ah->ar_sip, ah->ar_sha);
+            return;
+        }
+
+        if ((ah->ar_tip & slirp->vnetwork_mask.s_addr) ==
+            slirp->vnetwork_addr.s_addr) {
+            if (ah->ar_tip == slirp->vnameserver_addr.s_addr ||
+                ah->ar_tip == slirp->vhost_addr.s_addr)
+                goto arp_ok;
+            for (ex_ptr = slirp->exec_list; ex_ptr; ex_ptr = ex_ptr->ex_next) {
+                if (ex_ptr->ex_addr.s_addr == ah->ar_tip)
+                    goto arp_ok;
+            }
+            return;
+        arp_ok:
+            memset(arp_reply, 0, sizeof(arp_reply));
+
+            arp_table_add(slirp, ah->ar_sip, ah->ar_sha);
+
+            /* ARP request for alias/dns mac address */
+            memcpy(reh->h_dest, pkt + ETH_ALEN, ETH_ALEN);
+            memcpy(reh->h_source, special_ethaddr, ETH_ALEN - 4);
+            memcpy(&reh->h_source[2], &ah->ar_tip, 4);
+            reh->h_proto = htons(ETH_P_ARP);
+
+            rah->ar_hrd = htons(1);
+            rah->ar_pro = htons(ETH_P_IP);
+            rah->ar_hln = ETH_ALEN;
+            rah->ar_pln = 4;
+            rah->ar_op = htons(ARPOP_REPLY);
+            memcpy(rah->ar_sha, reh->h_source, ETH_ALEN);
+            rah->ar_sip = ah->ar_tip;
+            memcpy(rah->ar_tha, ah->ar_sha, ETH_ALEN);
+            rah->ar_tip = ah->ar_sip;
+            slirp_output(slirp->opaque, arp_reply, sizeof(arp_reply));
+        }
+        break;
+    case ARPOP_REPLY:
+        arp_table_add(slirp, ah->ar_sip, ah->ar_sha);
+        break;
+    default:
+        break;
+    }
+}
+
+void slirp_input(Slirp *slirp, const uint8_t *pkt, int pkt_len)
+{
+    struct mbuf *m;
+    int proto;
+
+    if (pkt_len < ETH_HLEN)
+        return;
+
+    proto = ntohs(*(uint16_t *)(pkt + 12));
+    switch(proto) {
+    case ETH_P_ARP:
+        arp_input(slirp, pkt, pkt_len);
+        break;
+    case ETH_P_IP:
+        m = m_get(slirp);
+        if (!m)
+            return;
+        /* Note: we add to align the IP header */
+        if (M_FREEROOM(m) < pkt_len + 2) {
+            m_inc(m, pkt_len + 2);
+        }
+        m->m_len = pkt_len + 2;
+        memcpy(m->m_data + 2, pkt, pkt_len);
+
+        m->m_data += 2 + ETH_HLEN;
+        m->m_len -= 2 + ETH_HLEN;
+
+        ip_input(m);
+        break;
+    default:
+        break;
+    }
+}
+
+/* Output the IP packet to the ethernet device. Returns 0 if the packet must be
+ * re-queued.
+ */
+int if_encap(Slirp *slirp, struct mbuf *ifm)
+{
+    uint8_t buf[1600];
+    struct ethhdr *eh = (struct ethhdr *)buf;
+    uint8_t ethaddr[ETH_ALEN];
+    const struct ip *iph = (const struct ip *)ifm->m_data;
+
+    if (ifm->m_len + ETH_HLEN > sizeof(buf)) {
+        return 1;
+    }
+
+    if (iph->ip_dst.s_addr == 0) {
+        /* 0.0.0.0 can not be a destination address, something went wrong,
+         * avoid making it worse */
+        return 1;
+    }
+    if (!arp_table_search(slirp, iph->ip_dst.s_addr, ethaddr)) {
+        uint8_t arp_req[ETH_HLEN + sizeof(struct arphdr)];
+        struct ethhdr *reh = (struct ethhdr *)arp_req;
+        struct arphdr *rah = (struct arphdr *)(arp_req + ETH_HLEN);
+
+        if (!ifm->arp_requested) {
+            /* If the client addr is not known, send an ARP request */
+            memset(reh->h_dest, 0xff, ETH_ALEN);
+            memcpy(reh->h_source, special_ethaddr, ETH_ALEN - 4);
+            memcpy(&reh->h_source[2], &slirp->vhost_addr, 4);
+            reh->h_proto = htons(ETH_P_ARP);
+            rah->ar_hrd = htons(1);
+            rah->ar_pro = htons(ETH_P_IP);
+            rah->ar_hln = ETH_ALEN;
+            rah->ar_pln = 4;
+            rah->ar_op = htons(ARPOP_REQUEST);
+
+            /* source hw addr */
+            memcpy(rah->ar_sha, special_ethaddr, ETH_ALEN - 4);
+            memcpy(&rah->ar_sha[2], &slirp->vhost_addr, 4);
+
+            /* source IP */
+            rah->ar_sip = slirp->vhost_addr.s_addr;
+
+            /* target hw addr (none) */
+            memset(rah->ar_tha, 0, ETH_ALEN);
+
+            /* target IP */
+            rah->ar_tip = iph->ip_dst.s_addr;
+            slirp->client_ipaddr = iph->ip_dst;
+            slirp_output(slirp->opaque, arp_req, sizeof(arp_req));
+            ifm->arp_requested = true;
+
+            /* Expire request and drop outgoing packet after 1 second */
+            ifm->expiration_date = qemu_clock_get_ns(QEMU_CLOCK_REALTIME) + 1000000000ULL;
+        }
+        return 0;
+    } else {
+        memcpy(eh->h_dest, ethaddr, ETH_ALEN);
+        memcpy(eh->h_source, special_ethaddr, ETH_ALEN - 4);
+        /* XXX: not correct */
+        memcpy(&eh->h_source[2], &slirp->vhost_addr, 4);
+        eh->h_proto = htons(ETH_P_IP);
+        memcpy(buf + sizeof(struct ethhdr), ifm->m_data, ifm->m_len);
+        slirp_output(slirp->opaque, buf, ifm->m_len + ETH_HLEN);
+        return 1;
+    }
+}
+
+/* Drop host forwarding rule, return 0 if found. */
+int slirp_remove_hostfwd(Slirp *slirp, int is_udp, struct in_addr host_addr,
+                         int host_port)
+{
+    struct socket *so;
+    struct socket *head = (is_udp ? &slirp->udb : &slirp->tcb);
+    struct sockaddr_in addr;
+    int port = htons(host_port);
+    socklen_t addr_len;
+
+    for (so = head->so_next; so != head; so = so->so_next) {
+        addr_len = sizeof(addr);
+        if ((so->so_state & SS_HOSTFWD) &&
+            getsockname(so->s, (struct sockaddr *)&addr, &addr_len) == 0 &&
+            addr.sin_addr.s_addr == host_addr.s_addr &&
+            addr.sin_port == port) {
+            close(so->s);
+            sofree(so);
+            return 0;
+        }
+    }
+
+    return -1;
+}
+
+int slirp_add_hostfwd(Slirp *slirp, int is_udp, struct in_addr host_addr,
+                      int host_port, struct in_addr guest_addr, int guest_port)
+{
+    if (!guest_addr.s_addr) {
+        guest_addr = slirp->vdhcp_startaddr;
+    }
+    if (is_udp) {
+        if (!udp_listen(slirp, host_addr.s_addr, htons(host_port),
+                        guest_addr.s_addr, htons(guest_port), SS_HOSTFWD))
+            return -1;
+    } else {
+        if (!tcp_listen(slirp, host_addr.s_addr, htons(host_port),
+                        guest_addr.s_addr, htons(guest_port), SS_HOSTFWD))
+            return -1;
+    }
+    return 0;
+}
+
+int slirp_add_exec(Slirp *slirp, int do_pty, const void *args,
+                   struct in_addr *guest_addr, int guest_port)
+{
+    if (!guest_addr->s_addr) {
+        guest_addr->s_addr = slirp->vnetwork_addr.s_addr |
+            (htonl(0x0204) & ~slirp->vnetwork_mask.s_addr);
+    }
+    if ((guest_addr->s_addr & slirp->vnetwork_mask.s_addr) !=
+        slirp->vnetwork_addr.s_addr ||
+        guest_addr->s_addr == slirp->vhost_addr.s_addr ||
+        guest_addr->s_addr == slirp->vnameserver_addr.s_addr) {
+        return -1;
+    }
+    return add_exec(&slirp->exec_list, do_pty, (char *)args, *guest_addr,
+                    htons(guest_port));
+}
+
+ssize_t slirp_send(struct socket *so, const void *buf, size_t len, int flags)
+{
+    if (so->s == -1 && so->extra) {
+        qemu_chr_fe_write(so->extra, buf, len);
+        return len;
+    }
+
+    return send(so->s, buf, len, flags);
+}
+
+static struct socket *
+slirp_find_ctl_socket(Slirp *slirp, struct in_addr guest_addr, int guest_port)
+{
+    struct socket *so;
+
+    for (so = slirp->tcb.so_next; so != &slirp->tcb; so = so->so_next) {
+        if (so->so_faddr.s_addr == guest_addr.s_addr &&
+            htons(so->so_fport) == guest_port) {
+            return so;
+        }
+    }
+    return NULL;
+}
+
+size_t slirp_socket_can_recv(Slirp *slirp, struct in_addr guest_addr,
+                             int guest_port)
+{
+    struct iovec iov[2];
+    struct socket *so;
+
+    so = slirp_find_ctl_socket(slirp, guest_addr, guest_port);
+
+    if (!so || so->so_state & SS_NOFDREF) {
+        return 0;
+    }
+
+    if (!CONN_CANFRCV(so) || so->so_snd.sb_cc >= (so->so_snd.sb_datalen/2)) {
+        return 0;
+    }
+
+    return sopreprbuf(so, iov, NULL);
+}
+
+void slirp_socket_recv(Slirp *slirp, struct in_addr guest_addr, int guest_port,
+                       const uint8_t *buf, int size)
+{
+    int ret;
+    struct socket *so = slirp_find_ctl_socket(slirp, guest_addr, guest_port);
+
+    if (!so)
+        return;
+
+    ret = soreadbuf(so, (const char *)buf, size);
+
+    if (ret > 0)
+        tcp_output(sototcpcb(so));
+}
+
+static void slirp_tcp_save(QEMUFile *f, struct tcpcb *tp)
+{
+    int i;
+
+    qemu_put_sbe16(f, tp->t_state);
+    for (i = 0; i < TCPT_NTIMERS; i++)
+        qemu_put_sbe16(f, tp->t_timer[i]);
+    qemu_put_sbe16(f, tp->t_rxtshift);
+    qemu_put_sbe16(f, tp->t_rxtcur);
+    qemu_put_sbe16(f, tp->t_dupacks);
+    qemu_put_be16(f, tp->t_maxseg);
+    qemu_put_sbyte(f, tp->t_force);
+    qemu_put_be16(f, tp->t_flags);
+    qemu_put_be32(f, tp->snd_una);
+    qemu_put_be32(f, tp->snd_nxt);
+    qemu_put_be32(f, tp->snd_up);
+    qemu_put_be32(f, tp->snd_wl1);
+    qemu_put_be32(f, tp->snd_wl2);
+    qemu_put_be32(f, tp->iss);
+    qemu_put_be32(f, tp->snd_wnd);
+    qemu_put_be32(f, tp->rcv_wnd);
+    qemu_put_be32(f, tp->rcv_nxt);
+    qemu_put_be32(f, tp->rcv_up);
+    qemu_put_be32(f, tp->irs);
+    qemu_put_be32(f, tp->rcv_adv);
+    qemu_put_be32(f, tp->snd_max);
+    qemu_put_be32(f, tp->snd_cwnd);
+    qemu_put_be32(f, tp->snd_ssthresh);
+    qemu_put_sbe16(f, tp->t_idle);
+    qemu_put_sbe16(f, tp->t_rtt);
+    qemu_put_be32(f, tp->t_rtseq);
+    qemu_put_sbe16(f, tp->t_srtt);
+    qemu_put_sbe16(f, tp->t_rttvar);
+    qemu_put_be16(f, tp->t_rttmin);
+    qemu_put_be32(f, tp->max_sndwnd);
+    qemu_put_byte(f, tp->t_oobflags);
+    qemu_put_byte(f, tp->t_iobc);
+    qemu_put_sbe16(f, tp->t_softerror);
+    qemu_put_byte(f, tp->snd_scale);
+    qemu_put_byte(f, tp->rcv_scale);
+    qemu_put_byte(f, tp->request_r_scale);
+    qemu_put_byte(f, tp->requested_s_scale);
+    qemu_put_be32(f, tp->ts_recent);
+    qemu_put_be32(f, tp->ts_recent_age);
+    qemu_put_be32(f, tp->last_ack_sent);
+}
+
+static void slirp_sbuf_save(QEMUFile *f, struct sbuf *sbuf)
+{
+    uint32_t off;
+
+    qemu_put_be32(f, sbuf->sb_cc);
+    qemu_put_be32(f, sbuf->sb_datalen);
+    off = (uint32_t)(sbuf->sb_wptr - sbuf->sb_data);
+    qemu_put_sbe32(f, off);
+    off = (uint32_t)(sbuf->sb_rptr - sbuf->sb_data);
+    qemu_put_sbe32(f, off);
+    qemu_put_buffer(f, (unsigned char*)sbuf->sb_data, sbuf->sb_datalen);
+}
+
+static void slirp_socket_save(QEMUFile *f, struct socket *so)
+{
+    qemu_put_be32(f, so->so_urgc);
+    qemu_put_be32(f, so->so_faddr.s_addr);
+    qemu_put_be32(f, so->so_laddr.s_addr);
+    qemu_put_be16(f, so->so_fport);
+    qemu_put_be16(f, so->so_lport);
+    qemu_put_byte(f, so->so_iptos);
+    qemu_put_byte(f, so->so_emu);
+    qemu_put_byte(f, so->so_type);
+    qemu_put_be32(f, so->so_state);
+    slirp_sbuf_save(f, &so->so_rcv);
+    slirp_sbuf_save(f, &so->so_snd);
+    slirp_tcp_save(f, so->so_tcpcb);
+}
+
+static void slirp_bootp_save(QEMUFile *f, Slirp *slirp)
+{
+    int i;
+
+    for (i = 0; i < NB_BOOTP_CLIENTS; i++) {
+        qemu_put_be16(f, slirp->bootp_clients[i].allocated);
+        qemu_put_buffer(f, slirp->bootp_clients[i].macaddr, 6);
+    }
+}
+
+static void slirp_state_save(QEMUFile *f, void *opaque)
+{
+    Slirp *slirp = opaque;
+    struct ex_list *ex_ptr;
+
+    for (ex_ptr = slirp->exec_list; ex_ptr; ex_ptr = ex_ptr->ex_next)
+        if (ex_ptr->ex_pty == 3) {
+            struct socket *so;
+            so = slirp_find_ctl_socket(slirp, ex_ptr->ex_addr,
+                                       ntohs(ex_ptr->ex_fport));
+            if (!so)
+                continue;
+
+            qemu_put_byte(f, 42);
+            slirp_socket_save(f, so);
+        }
+    qemu_put_byte(f, 0);
+
+    qemu_put_be16(f, slirp->ip_id);
+
+    slirp_bootp_save(f, slirp);
+}
+
+static void slirp_tcp_load(QEMUFile *f, struct tcpcb *tp)
+{
+    int i;
+
+    tp->t_state = qemu_get_sbe16(f);
+    for (i = 0; i < TCPT_NTIMERS; i++)
+        tp->t_timer[i] = qemu_get_sbe16(f);
+    tp->t_rxtshift = qemu_get_sbe16(f);
+    tp->t_rxtcur = qemu_get_sbe16(f);
+    tp->t_dupacks = qemu_get_sbe16(f);
+    tp->t_maxseg = qemu_get_be16(f);
+    tp->t_force = qemu_get_sbyte(f);
+    tp->t_flags = qemu_get_be16(f);
+    tp->snd_una = qemu_get_be32(f);
+    tp->snd_nxt = qemu_get_be32(f);
+    tp->snd_up = qemu_get_be32(f);
+    tp->snd_wl1 = qemu_get_be32(f);
+    tp->snd_wl2 = qemu_get_be32(f);
+    tp->iss = qemu_get_be32(f);
+    tp->snd_wnd = qemu_get_be32(f);
+    tp->rcv_wnd = qemu_get_be32(f);
+    tp->rcv_nxt = qemu_get_be32(f);
+    tp->rcv_up = qemu_get_be32(f);
+    tp->irs = qemu_get_be32(f);
+    tp->rcv_adv = qemu_get_be32(f);
+    tp->snd_max = qemu_get_be32(f);
+    tp->snd_cwnd = qemu_get_be32(f);
+    tp->snd_ssthresh = qemu_get_be32(f);
+    tp->t_idle = qemu_get_sbe16(f);
+    tp->t_rtt = qemu_get_sbe16(f);
+    tp->t_rtseq = qemu_get_be32(f);
+    tp->t_srtt = qemu_get_sbe16(f);
+    tp->t_rttvar = qemu_get_sbe16(f);
+    tp->t_rttmin = qemu_get_be16(f);
+    tp->max_sndwnd = qemu_get_be32(f);
+    tp->t_oobflags = qemu_get_byte(f);
+    tp->t_iobc = qemu_get_byte(f);
+    tp->t_softerror = qemu_get_sbe16(f);
+    tp->snd_scale = qemu_get_byte(f);
+    tp->rcv_scale = qemu_get_byte(f);
+    tp->request_r_scale = qemu_get_byte(f);
+    tp->requested_s_scale = qemu_get_byte(f);
+    tp->ts_recent = qemu_get_be32(f);
+    tp->ts_recent_age = qemu_get_be32(f);
+    tp->last_ack_sent = qemu_get_be32(f);
+    tcp_template(tp);
+}
+
+static int slirp_sbuf_load(QEMUFile *f, struct sbuf *sbuf)
+{
+    uint32_t off, sb_cc, sb_datalen;
+
+    sb_cc = qemu_get_be32(f);
+    sb_datalen = qemu_get_be32(f);
+
+    sbreserve(sbuf, sb_datalen);
+
+    if (sbuf->sb_datalen != sb_datalen)
+        return -ENOMEM;
+
+    sbuf->sb_cc = sb_cc;
+
+    off = qemu_get_sbe32(f);
+    sbuf->sb_wptr = sbuf->sb_data + off;
+    off = qemu_get_sbe32(f);
+    sbuf->sb_rptr = sbuf->sb_data + off;
+    qemu_get_buffer(f, (unsigned char*)sbuf->sb_data, sbuf->sb_datalen);
+
+    return 0;
+}
+
+static int slirp_socket_load(QEMUFile *f, struct socket *so)
+{
+    if (tcp_attach(so) < 0)
+        return -ENOMEM;
+
+    so->so_urgc = qemu_get_be32(f);
+    so->so_faddr.s_addr = qemu_get_be32(f);
+    so->so_laddr.s_addr = qemu_get_be32(f);
+    so->so_fport = qemu_get_be16(f);
+    so->so_lport = qemu_get_be16(f);
+    so->so_iptos = qemu_get_byte(f);
+    so->so_emu = qemu_get_byte(f);
+    so->so_type = qemu_get_byte(f);
+    so->so_state = qemu_get_be32(f);
+    if (slirp_sbuf_load(f, &so->so_rcv) < 0)
+        return -ENOMEM;
+    if (slirp_sbuf_load(f, &so->so_snd) < 0)
+        return -ENOMEM;
+    slirp_tcp_load(f, so->so_tcpcb);
+
+    return 0;
+}
+
+static void slirp_bootp_load(QEMUFile *f, Slirp *slirp)
+{
+    int i;
+
+    for (i = 0; i < NB_BOOTP_CLIENTS; i++) {
+        slirp->bootp_clients[i].allocated = qemu_get_be16(f);
+        qemu_get_buffer(f, slirp->bootp_clients[i].macaddr, 6);
+    }
+}
+
+static int slirp_state_load(QEMUFile *f, void *opaque, int version_id)
+{
+    Slirp *slirp = opaque;
+    struct ex_list *ex_ptr;
+
+    while (qemu_get_byte(f)) {
+        int ret;
+        struct socket *so = socreate(slirp);
+
+        if (!so)
+            return -ENOMEM;
+
+        ret = slirp_socket_load(f, so);
+
+        if (ret < 0)
+            return ret;
+
+        if ((so->so_faddr.s_addr & slirp->vnetwork_mask.s_addr) !=
+            slirp->vnetwork_addr.s_addr) {
+            return -EINVAL;
+        }
+        for (ex_ptr = slirp->exec_list; ex_ptr; ex_ptr = ex_ptr->ex_next) {
+            if (ex_ptr->ex_pty == 3 &&
+                so->so_faddr.s_addr == ex_ptr->ex_addr.s_addr &&
+                so->so_fport == ex_ptr->ex_fport) {
+                break;
+            }
+        }
+        if (!ex_ptr)
+            return -EINVAL;
+
+        so->extra = (void *)ex_ptr->ex_exec;
+    }
+
+    if (version_id >= 2) {
+        slirp->ip_id = qemu_get_be16(f);
+    }
+
+    if (version_id >= 3) {
+        slirp_bootp_load(f, slirp);
+    }
+
+    return 0;
+}
diff --git a/src/slirp/slirp.h b/src/slirp/slirp.h
new file mode 100644
index 0000000..6589d7e
--- /dev/null
+++ b/src/slirp/slirp.h
@@ -0,0 +1,361 @@
+#ifndef __COMMON_H__
+#define __COMMON_H__
+
+#include "config-host.h"
+#include "slirp_config.h"
+
+#ifdef _WIN32
+# include <inttypes.h>
+
+typedef char *caddr_t;
+
+# include <windows.h>
+# include <winsock2.h>
+# include <ws2tcpip.h>
+# include <sys/timeb.h>
+# include <iphlpapi.h>
+
+#else
+# define ioctlsocket ioctl
+# define closesocket(s) close(s)
+# if !defined(__HAIKU__)
+#  define O_BINARY 0
+# endif
+#endif
+
+#include <sys/types.h>
+#ifdef HAVE_SYS_BITYPES_H
+# include <sys/bitypes.h>
+#endif
+
+#include <sys/time.h>
+
+#ifdef HAVE_UNISTD_H
+# include <unistd.h>
+#endif
+
+#ifdef HAVE_STDLIB_H
+# include <stdlib.h>
+#endif
+
+#include <stdio.h>
+#include <errno.h>
+
+#ifndef HAVE_MEMMOVE
+#define memmove(x, y, z) bcopy(y, x, z)
+#endif
+
+#if TIME_WITH_SYS_TIME
+# include <sys/time.h>
+# include <time.h>
+#else
+# ifdef HAVE_SYS_TIME_H
+#  include <sys/time.h>
+# else
+#  include <time.h>
+# endif
+#endif
+
+#ifdef HAVE_STRING_H
+# include <string.h>
+#else
+# include <strings.h>
+#endif
+
+#ifndef _WIN32
+#include <sys/uio.h>
+#endif
+
+#ifndef _WIN32
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#endif
+
+/* Systems lacking strdup() definition in <string.h>. */
+#if defined(ultrix)
+char *strdup(const char *);
+#endif
+
+/* Systems lacking malloc() definition in <stdlib.h>. */
+#if defined(ultrix) || defined(hcx)
+void *malloc(size_t arg);
+void free(void *ptr);
+#endif
+
+#include <fcntl.h>
+#ifndef NO_UNIX_SOCKETS
+#include <sys/un.h>
+#endif
+#include <signal.h>
+#ifdef HAVE_SYS_SIGNAL_H
+# include <sys/signal.h>
+#endif
+#ifndef _WIN32
+#include <sys/socket.h>
+#endif
+
+#if defined(HAVE_SYS_IOCTL_H)
+# include <sys/ioctl.h>
+#endif
+
+#ifdef HAVE_SYS_SELECT_H
+# include <sys/select.h>
+#endif
+
+#ifdef HAVE_SYS_WAIT_H
+# include <sys/wait.h>
+#endif
+
+#ifdef HAVE_SYS_FILIO_H
+# include <sys/filio.h>
+#endif
+
+#ifdef USE_PPP
+#include <ppp/slirppp.h>
+#endif
+
+#ifdef __STDC__
+#include <stdarg.h>
+#else
+#include <varargs.h>
+#endif
+
+#include <sys/stat.h>
+
+/* Avoid conflicting with the libc insque() and remque(), which
+   have different prototypes. */
+#define insque slirp_insque
+#define remque slirp_remque
+
+#ifdef HAVE_SYS_STROPTS_H
+#include <sys/stropts.h>
+#endif
+
+#include "debug.h"
+
+#include "qemu/queue.h"
+#include "qemu/sockets.h"
+
+#include "libslirp.h"
+#include "ip.h"
+#include "tcp.h"
+#include "tcp_timer.h"
+#include "tcp_var.h"
+#include "tcpip.h"
+#include "udp.h"
+#include "ip_icmp.h"
+#include "mbuf.h"
+#include "sbuf.h"
+#include "socket.h"
+#include "if.h"
+#include "main.h"
+#include "misc.h"
+#ifdef USE_PPP
+#include "ppp/pppd.h"
+#include "ppp/ppp.h"
+#endif
+
+#include "bootp.h"
+#include "tftp.h"
+
+#define ETH_ALEN 6
+#define ETH_HLEN 14
+
+#define ETH_P_IP  0x0800        /* Internet Protocol packet  */
+#define ETH_P_ARP 0x0806        /* Address Resolution packet */
+
+#define ARPOP_REQUEST 1         /* ARP request */
+#define ARPOP_REPLY   2         /* ARP reply   */
+
+struct ethhdr {
+    unsigned char  h_dest[ETH_ALEN];   /* destination eth addr */
+    unsigned char  h_source[ETH_ALEN]; /* source ether addr    */
+    unsigned short h_proto;            /* packet type ID field */
+};
+
+struct arphdr {
+    unsigned short ar_hrd;      /* format of hardware address */
+    unsigned short ar_pro;      /* format of protocol address */
+    unsigned char  ar_hln;      /* length of hardware address */
+    unsigned char  ar_pln;      /* length of protocol address */
+    unsigned short ar_op;       /* ARP opcode (command)       */
+
+    /*
+     *  Ethernet looks like this : This bit is variable sized however...
+     */
+    unsigned char ar_sha[ETH_ALEN]; /* sender hardware address */
+    uint32_t      ar_sip;           /* sender IP address       */
+    unsigned char ar_tha[ETH_ALEN]; /* target hardware address */
+    uint32_t      ar_tip;           /* target IP address       */
+} QEMU_PACKED;
+
+#define ARP_TABLE_SIZE 16
+
+typedef struct ArpTable {
+    struct arphdr table[ARP_TABLE_SIZE];
+    int next_victim;
+} ArpTable;
+
+void arp_table_add(Slirp *slirp, uint32_t ip_addr, uint8_t ethaddr[ETH_ALEN]);
+
+bool arp_table_search(Slirp *slirp, uint32_t ip_addr,
+                      uint8_t out_ethaddr[ETH_ALEN]);
+
+struct Slirp {
+    QTAILQ_ENTRY(Slirp) entry;
+    u_int time_fasttimo;
+    u_int last_slowtimo;
+    bool do_slowtimo;
+
+    /* virtual network configuration */
+    struct in_addr vnetwork_addr;
+    struct in_addr vnetwork_mask;
+    struct in_addr vhost_addr;
+    struct in_addr vdhcp_startaddr;
+    struct in_addr vnameserver_addr;
+
+    struct in_addr client_ipaddr;
+    char client_hostname[33];
+
+    int restricted;
+    struct ex_list *exec_list;
+
+    /* mbuf states */
+    struct mbuf m_freelist, m_usedlist;
+    int mbuf_alloced;
+
+    /* if states */
+    struct mbuf if_fastq;   /* fast queue (for interactive data) */
+    struct mbuf if_batchq;  /* queue for non-interactive data */
+    struct mbuf *next_m;    /* pointer to next mbuf to output */
+    bool if_start_busy;     /* avoid if_start recursion */
+
+    /* ip states */
+    struct ipq ipq;         /* ip reass. queue */
+    uint16_t ip_id;         /* ip packet ctr, for ids */
+
+    /* bootp/dhcp states */
+    BOOTPClient bootp_clients[NB_BOOTP_CLIENTS];
+    char *bootp_filename;
+    size_t vdnssearch_len;
+    uint8_t *vdnssearch;
+
+    /* tcp states */
+    struct socket tcb;
+    struct socket *tcp_last_so;
+    tcp_seq tcp_iss;        /* tcp initial send seq # */
+    uint32_t tcp_now;       /* for RFC 1323 timestamps */
+
+    /* udp states */
+    struct socket udb;
+    struct socket *udp_last_so;
+
+    /* icmp states */
+    struct socket icmp;
+    struct socket *icmp_last_so;
+
+    /* tftp states */
+    char *tftp_prefix;
+    struct tftp_session tftp_sessions[TFTP_SESSIONS_MAX];
+
+    ArpTable arp_table;
+
+    void *opaque;
+};
+
+extern Slirp *slirp_instance;
+
+#ifndef NULL
+#define NULL (void *)0
+#endif
+
+#ifndef FULL_BOLT
+void if_start(Slirp *);
+#else
+void if_start(struct ttys *);
+#endif
+
+#ifndef HAVE_STRERROR
+ char *strerror(int error);
+#endif
+
+#ifndef HAVE_INDEX
+ char *index(const char *, int);
+#endif
+
+#ifndef HAVE_GETHOSTID
+ long gethostid(void);
+#endif
+
+#ifndef _WIN32
+#include <netdb.h>
+#endif
+
+#define DEFAULT_BAUD 115200
+
+#define SO_OPTIONS DO_KEEPALIVE
+#define TCP_MAXIDLE (TCPTV_KEEPCNT * TCPTV_KEEPINTVL)
+
+/* dnssearch.c */
+int translate_dnssearch(Slirp *s, const char ** names);
+
+/* cksum.c */
+int cksum(struct mbuf *m, int len);
+
+/* if.c */
+void if_init(Slirp *);
+void if_output(struct socket *, struct mbuf *);
+
+/* ip_input.c */
+void ip_init(Slirp *);
+void ip_cleanup(Slirp *);
+void ip_input(struct mbuf *);
+void ip_slowtimo(Slirp *);
+void ip_stripoptions(register struct mbuf *, struct mbuf *);
+
+/* ip_output.c */
+int ip_output(struct socket *, struct mbuf *);
+
+/* tcp_input.c */
+void tcp_input(register struct mbuf *, int, struct socket *);
+int tcp_mss(register struct tcpcb *, u_int);
+
+/* tcp_output.c */
+int tcp_output(register struct tcpcb *);
+void tcp_setpersist(register struct tcpcb *);
+
+/* tcp_subr.c */
+void tcp_init(Slirp *);
+void tcp_cleanup(Slirp *);
+void tcp_template(struct tcpcb *);
+void tcp_respond(struct tcpcb *, register struct tcpiphdr *, register struct mbuf *, tcp_seq, tcp_seq, int);
+struct tcpcb * tcp_newtcpcb(struct socket *);
+struct tcpcb * tcp_close(register struct tcpcb *);
+void tcp_sockclosed(struct tcpcb *);
+int tcp_fconnect(struct socket *);
+void tcp_connect(struct socket *);
+int tcp_attach(struct socket *);
+uint8_t tcp_tos(struct socket *);
+int tcp_emu(struct socket *, struct mbuf *);
+int tcp_ctl(struct socket *);
+struct tcpcb *tcp_drop(struct tcpcb *tp, int err);
+
+#ifdef USE_PPP
+#define MIN_MRU MINMRU
+#define MAX_MRU MAXMRU
+#else
+#define MIN_MRU 128
+#define MAX_MRU 16384
+#endif
+
+#ifndef _WIN32
+#define min(x,y) ((x) < (y) ? (x) : (y))
+#define max(x,y) ((x) > (y) ? (x) : (y))
+#endif
+
+#ifdef _WIN32
+#undef errno
+#define errno (WSAGetLastError())
+#endif
+
+#endif
diff --git a/src/slirp/slirp_config.h b/src/slirp/slirp_config.h
new file mode 100644
index 0000000..896d802
--- /dev/null
+++ b/src/slirp/slirp_config.h
@@ -0,0 +1,185 @@
+/*
+ * User definable configuration options
+ */
+
+/* Define if you want the connection to be probed */
+/* XXX Not working yet, so ignore this for now */
+#undef PROBE_CONN
+
+/* Define to 1 if you want KEEPALIVE timers */
+#define DO_KEEPALIVE 0
+
+/* Define to MAX interfaces you expect to use at once */
+/* MAX_INTERFACES determines the max. TOTAL number of interfaces (SLIP and PPP) */
+/* MAX_PPP_INTERFACES determines max. number of PPP interfaces */
+#define MAX_INTERFACES 1
+#define MAX_PPP_INTERFACES 1
+
+/* Define if you want slirp's socket in /tmp */
+/* XXXXXX Do this in ./configure */
+#undef USE_TMPSOCKET
+
+/* Define if you want slirp to use cfsetXspeed() on the terminal */
+#undef DO_CFSETSPEED
+
+/* Define this if you want slirp to write to the tty as fast as it can */
+/* This should only be set if you are using load-balancing, slirp does a */
+/* pretty good job on single modems already, and seting this will make */
+/* interactive sessions less responsive */
+/* XXXXX Talk about having fast modem as unit 0 */
+#undef FULL_BOLT
+
+/*
+ * Define if you want slirp to use less CPU
+ * You will notice a small lag in interactive sessions, but it's not that bad
+ * Things like Netscape/ftp/etc. are completely unaffected
+ * This is mainly for sysadmins who have many slirp users
+ */
+#undef USE_LOWCPU
+
+/* Define this if your compiler doesn't like prototypes */
+#ifndef __STDC__
+#define NO_PROTOTYPES
+#endif
+
+/*********************************************************/
+/*
+ * Autoconf defined configuration options
+ * You shouldn't need to touch any of these
+ */
+
+/* Ignore this */
+#undef DUMMY_PPP
+
+/* Define if you have unistd.h */
+#define HAVE_UNISTD_H
+
+/* Define if you have stdlib.h */
+#define HAVE_STDLIB_H
+
+/* Define if you have sys/ioctl.h */
+#undef HAVE_SYS_IOCTL_H
+#ifndef _WIN32
+#define HAVE_SYS_IOCTL_H
+#endif
+
+/* Define if you have sys/filio.h */
+#undef HAVE_SYS_FILIO_H
+#ifdef __APPLE__
+#define HAVE_SYS_FILIO_H
+#endif
+
+/* Define if you have strerror */
+#define HAVE_STRERROR
+
+/* Define according to how time.h should be included */
+#define TIME_WITH_SYS_TIME 0
+#undef HAVE_SYS_TIME_H
+
+/* Define if you have sys/bitypes.h */
+#undef HAVE_SYS_BITYPES_H
+
+/* Define if the machine is big endian */
+//#undef HOST_WORDS_BIGENDIAN
+
+/* Define if you have readv */
+#undef HAVE_READV
+
+/* Define if iovec needs to be declared */
+#undef DECLARE_IOVEC
+#ifdef _WIN32
+#define DECLARE_IOVEC
+#endif
+
+/* Define if you have a POSIX.1 sys/wait.h */
+#undef HAVE_SYS_WAIT_H
+
+/* Define if you have sys/select.h */
+#undef HAVE_SYS_SELECT_H
+#ifndef _WIN32
+#define HAVE_SYS_SELECT_H
+#endif
+
+/* Define if you have strings.h */
+#define HAVE_STRING_H
+
+/* Define if you have arpa/inet.h */
+#undef HAVE_ARPA_INET_H
+#ifndef _WIN32
+#define HAVE_ARPA_INET_H
+#endif
+
+/* Define if you have sys/signal.h */
+#undef HAVE_SYS_SIGNAL_H
+
+/* Define if you have sys/stropts.h */
+#undef HAVE_SYS_STROPTS_H
+
+/* Define to whatever your compiler thinks inline should be */
+//#define inline inline
+
+/* Define to whatever your compiler thinks const should be */
+//#define const const
+
+/* Define if your compiler doesn't like prototypes */
+#undef NO_PROTOTYPES
+
+/* Define to sizeof(char) */
+#define SIZEOF_CHAR 1
+
+/* Define to sizeof(short) */
+#define SIZEOF_SHORT 2
+
+/* Define to sizeof(int) */
+#define SIZEOF_INT 4
+
+/* Define to sizeof(char *) */
+#define SIZEOF_CHAR_P (HOST_LONG_BITS / 8)
+
+/* Define if you have random() */
+#undef HAVE_RANDOM
+
+/* Define if you have srandom() */
+#undef HAVE_SRANDOM
+
+/* Define if you have inet_aton */
+#undef HAVE_INET_ATON
+#ifndef _WIN32
+#define HAVE_INET_ATON
+#endif
+
+/* Define if you have setenv */
+#undef HAVE_SETENV
+
+/* Define if you have index() */
+#define HAVE_INDEX
+
+/* Define if you have bcmp() */
+#undef HAVE_BCMP
+
+/* Define if you have drand48 */
+#undef HAVE_DRAND48
+
+/* Define if you have memmove */
+#define HAVE_MEMMOVE
+
+/* Define if you have gethostid */
+#define HAVE_GETHOSTID
+
+/* Define if you DON'T have unix-domain sockets */
+#undef NO_UNIX_SOCKETS
+#ifdef _WIN32
+#define NO_UNIX_SOCKETS
+#endif
+
+/* Define if you have revoke() */
+#undef HAVE_REVOKE
+
+/* Define if you have the sysv method of opening pty's (/dev/ptmx, etc.) */
+#undef HAVE_GRANTPT
+
+/* Define if you have fchmod */
+#undef HAVE_FCHMOD
+
+/* Define if you have <sys/type32.h> */
+#undef HAVE_SYS_TYPES32_H
diff --git a/src/slirp/socket.c b/src/slirp/socket.c
new file mode 100644
index 0000000..1673e3a
--- /dev/null
+++ b/src/slirp/socket.c
@@ -0,0 +1,720 @@
+/*
+ * Copyright (c) 1995 Danny Gasparovski.
+ *
+ * Please read the file COPYRIGHT for the
+ * terms and conditions of the copyright.
+ */
+
+#include "qemu-common.h"
+#include <slirp.h>
+#include "ip_icmp.h"
+#ifdef __sun__
+#include <sys/filio.h>
+#endif
+
+static void sofcantrcvmore(struct socket *so);
+static void sofcantsendmore(struct socket *so);
+
+struct socket *
+solookup(struct socket *head, struct in_addr laddr, u_int lport,
+         struct in_addr faddr, u_int fport)
+{
+	struct socket *so;
+
+	for (so = head->so_next; so != head; so = so->so_next) {
+		if (so->so_lport == lport &&
+		    so->so_laddr.s_addr == laddr.s_addr &&
+		    so->so_faddr.s_addr == faddr.s_addr &&
+		    so->so_fport == fport)
+		   break;
+	}
+
+	if (so == head)
+	   return (struct socket *)NULL;
+	return so;
+
+}
+
+/*
+ * Create a new socket, initialise the fields
+ * It is the responsibility of the caller to
+ * insque() it into the correct linked-list
+ */
+struct socket *
+socreate(Slirp *slirp)
+{
+  struct socket *so;
+
+  so = (struct socket *)malloc(sizeof(struct socket));
+  if(so) {
+    memset(so, 0, sizeof(struct socket));
+    so->so_state = SS_NOFDREF;
+    so->s = -1;
+    so->slirp = slirp;
+    so->pollfds_idx = -1;
+  }
+  return(so);
+}
+
+/*
+ * remque and free a socket, clobber cache
+ */
+void
+sofree(struct socket *so)
+{
+  Slirp *slirp = so->slirp;
+
+  if (so->so_emu==EMU_RSH && so->extra) {
+	sofree(so->extra);
+	so->extra=NULL;
+  }
+  if (so == slirp->tcp_last_so) {
+      slirp->tcp_last_so = &slirp->tcb;
+  } else if (so == slirp->udp_last_so) {
+      slirp->udp_last_so = &slirp->udb;
+  } else if (so == slirp->icmp_last_so) {
+      slirp->icmp_last_so = &slirp->icmp;
+  }
+  m_free(so->so_m);
+
+  if(so->so_next && so->so_prev)
+    remque(so);  /* crashes if so is not in a queue */
+
+  free(so);
+}
+
+size_t sopreprbuf(struct socket *so, struct iovec *iov, int *np)
+{
+	int n, lss, total;
+	struct sbuf *sb = &so->so_snd;
+	int len = sb->sb_datalen - sb->sb_cc;
+	int mss = so->so_tcpcb->t_maxseg;
+
+	DEBUG_CALL("sopreprbuf");
+	DEBUG_ARG("so = %p", so);
+
+	if (len <= 0)
+		return 0;
+
+	iov[0].iov_base = sb->sb_wptr;
+        iov[1].iov_base = NULL;
+        iov[1].iov_len = 0;
+	if (sb->sb_wptr < sb->sb_rptr) {
+		iov[0].iov_len = sb->sb_rptr - sb->sb_wptr;
+		/* Should never succeed, but... */
+		if (iov[0].iov_len > len)
+		   iov[0].iov_len = len;
+		if (iov[0].iov_len > mss)
+		   iov[0].iov_len -= iov[0].iov_len%mss;
+		n = 1;
+	} else {
+		iov[0].iov_len = (sb->sb_data + sb->sb_datalen) - sb->sb_wptr;
+		/* Should never succeed, but... */
+		if (iov[0].iov_len > len) iov[0].iov_len = len;
+		len -= iov[0].iov_len;
+		if (len) {
+			iov[1].iov_base = sb->sb_data;
+			iov[1].iov_len = sb->sb_rptr - sb->sb_data;
+			if(iov[1].iov_len > len)
+			   iov[1].iov_len = len;
+			total = iov[0].iov_len + iov[1].iov_len;
+			if (total > mss) {
+				lss = total%mss;
+				if (iov[1].iov_len > lss) {
+					iov[1].iov_len -= lss;
+					n = 2;
+				} else {
+					lss -= iov[1].iov_len;
+					iov[0].iov_len -= lss;
+					n = 1;
+				}
+			} else
+				n = 2;
+		} else {
+			if (iov[0].iov_len > mss)
+			   iov[0].iov_len -= iov[0].iov_len%mss;
+			n = 1;
+		}
+	}
+	if (np)
+		*np = n;
+
+	return iov[0].iov_len + (n - 1) * iov[1].iov_len;
+}
+
+/*
+ * Read from so's socket into sb_snd, updating all relevant sbuf fields
+ * NOTE: This will only be called if it is select()ed for reading, so
+ * a read() of 0 (or less) means it's disconnected
+ */
+int
+soread(struct socket *so)
+{
+	int n, nn;
+	struct sbuf *sb = &so->so_snd;
+	struct iovec iov[2];
+
+	DEBUG_CALL("soread");
+	DEBUG_ARG("so = %p", so);
+
+	/*
+	 * No need to check if there's enough room to read.
+	 * soread wouldn't have been called if there weren't
+	 */
+	sopreprbuf(so, iov, &n);
+
+#ifdef HAVE_READV
+	nn = readv(so->s, (struct iovec *)iov, n);
+	DEBUG_MISC((dfd, " ... read nn = %d bytes\n", nn));
+#else
+	nn = qemu_recv(so->s, iov[0].iov_base, iov[0].iov_len,0);
+#endif
+	if (nn <= 0) {
+		if (nn < 0 && (errno == EINTR || errno == EAGAIN))
+			return 0;
+		else {
+			DEBUG_MISC((dfd, " --- soread() disconnected, nn = %d, errno = %d-%s\n", nn, errno,strerror(errno)));
+			sofcantrcvmore(so);
+			tcp_sockclosed(sototcpcb(so));
+			return -1;
+		}
+	}
+
+#ifndef HAVE_READV
+	/*
+	 * If there was no error, try and read the second time round
+	 * We read again if n = 2 (ie, there's another part of the buffer)
+	 * and we read as much as we could in the first read
+	 * We don't test for <= 0 this time, because there legitimately
+	 * might not be any more data (since the socket is non-blocking),
+	 * a close will be detected on next iteration.
+	 * A return of -1 wont (shouldn't) happen, since it didn't happen above
+	 */
+	if (n == 2 && nn == iov[0].iov_len) {
+            int ret;
+            ret = qemu_recv(so->s, iov[1].iov_base, iov[1].iov_len,0);
+            if (ret > 0)
+                nn += ret;
+        }
+
+	DEBUG_MISC((dfd, " ... read nn = %d bytes\n", nn));
+#endif
+
+	/* Update fields */
+	sb->sb_cc += nn;
+	sb->sb_wptr += nn;
+	if (sb->sb_wptr >= (sb->sb_data + sb->sb_datalen))
+		sb->sb_wptr -= sb->sb_datalen;
+	return nn;
+}
+
+int soreadbuf(struct socket *so, const char *buf, int size)
+{
+    int n, nn, copy = size;
+	struct sbuf *sb = &so->so_snd;
+	struct iovec iov[2];
+
+	DEBUG_CALL("soreadbuf");
+	DEBUG_ARG("so = %p", so);
+
+	/*
+	 * No need to check if there's enough room to read.
+	 * soread wouldn't have been called if there weren't
+	 */
+	if (sopreprbuf(so, iov, &n) < size)
+        goto err;
+
+    nn = MIN(iov[0].iov_len, copy);
+    memcpy(iov[0].iov_base, buf, nn);
+
+    copy -= nn;
+    buf += nn;
+
+    if (copy == 0)
+        goto done;
+
+    memcpy(iov[1].iov_base, buf, copy);
+
+done:
+    /* Update fields */
+	sb->sb_cc += size;
+	sb->sb_wptr += size;
+	if (sb->sb_wptr >= (sb->sb_data + sb->sb_datalen))
+		sb->sb_wptr -= sb->sb_datalen;
+    return size;
+err:
+
+    sofcantrcvmore(so);
+    tcp_sockclosed(sototcpcb(so));
+    fprintf(stderr, "soreadbuf buffer to small");
+    return -1;
+}
+
+/*
+ * Get urgent data
+ *
+ * When the socket is created, we set it SO_OOBINLINE,
+ * so when OOB data arrives, we soread() it and everything
+ * in the send buffer is sent as urgent data
+ */
+void
+sorecvoob(struct socket *so)
+{
+	struct tcpcb *tp = sototcpcb(so);
+
+	DEBUG_CALL("sorecvoob");
+	DEBUG_ARG("so = %p", so);
+
+	/*
+	 * We take a guess at how much urgent data has arrived.
+	 * In most situations, when urgent data arrives, the next
+	 * read() should get all the urgent data.  This guess will
+	 * be wrong however if more data arrives just after the
+	 * urgent data, or the read() doesn't return all the
+	 * urgent data.
+	 */
+	soread(so);
+	tp->snd_up = tp->snd_una + so->so_snd.sb_cc;
+	tp->t_force = 1;
+	tcp_output(tp);
+	tp->t_force = 0;
+}
+
+/*
+ * Send urgent data
+ * There's a lot duplicated code here, but...
+ */
+int
+sosendoob(struct socket *so)
+{
+	struct sbuf *sb = &so->so_rcv;
+	char buff[2048]; /* XXX Shouldn't be sending more oob data than this */
+
+	int n, len;
+
+	DEBUG_CALL("sosendoob");
+	DEBUG_ARG("so = %p", so);
+	DEBUG_ARG("sb->sb_cc = %d", sb->sb_cc);
+
+	if (so->so_urgc > 2048)
+	   so->so_urgc = 2048; /* XXXX */
+
+	if (sb->sb_rptr < sb->sb_wptr) {
+		/* We can send it directly */
+		n = slirp_send(so, sb->sb_rptr, so->so_urgc, (MSG_OOB)); /* |MSG_DONTWAIT)); */
+		so->so_urgc -= n;
+
+		DEBUG_MISC((dfd, " --- sent %d bytes urgent data, %d urgent bytes left\n", n, so->so_urgc));
+	} else {
+		/*
+		 * Since there's no sendv or sendtov like writev,
+		 * we must copy all data to a linear buffer then
+		 * send it all
+		 */
+		len = (sb->sb_data + sb->sb_datalen) - sb->sb_rptr;
+		if (len > so->so_urgc) len = so->so_urgc;
+		memcpy(buff, sb->sb_rptr, len);
+		so->so_urgc -= len;
+		if (so->so_urgc) {
+			n = sb->sb_wptr - sb->sb_data;
+			if (n > so->so_urgc) n = so->so_urgc;
+			memcpy((buff + len), sb->sb_data, n);
+			so->so_urgc -= n;
+			len += n;
+		}
+		n = slirp_send(so, buff, len, (MSG_OOB)); /* |MSG_DONTWAIT)); */
+#ifdef DEBUG
+		if (n != len)
+		   DEBUG_ERROR((dfd, "Didn't send all data urgently XXXXX\n"));
+#endif
+		DEBUG_MISC((dfd, " ---2 sent %d bytes urgent data, %d urgent bytes left\n", n, so->so_urgc));
+	}
+
+	sb->sb_cc -= n;
+	sb->sb_rptr += n;
+	if (sb->sb_rptr >= (sb->sb_data + sb->sb_datalen))
+		sb->sb_rptr -= sb->sb_datalen;
+
+	return n;
+}
+
+/*
+ * Write data from so_rcv to so's socket,
+ * updating all sbuf field as necessary
+ */
+int
+sowrite(struct socket *so)
+{
+	int  n,nn;
+	struct sbuf *sb = &so->so_rcv;
+	int len = sb->sb_cc;
+	struct iovec iov[2];
+
+	DEBUG_CALL("sowrite");
+	DEBUG_ARG("so = %p", so);
+
+	if (so->so_urgc) {
+		sosendoob(so);
+		if (sb->sb_cc == 0)
+			return 0;
+	}
+
+	/*
+	 * No need to check if there's something to write,
+	 * sowrite wouldn't have been called otherwise
+	 */
+
+	iov[0].iov_base = sb->sb_rptr;
+        iov[1].iov_base = NULL;
+        iov[1].iov_len = 0;
+	if (sb->sb_rptr < sb->sb_wptr) {
+		iov[0].iov_len = sb->sb_wptr - sb->sb_rptr;
+		/* Should never succeed, but... */
+		if (iov[0].iov_len > len) iov[0].iov_len = len;
+		n = 1;
+	} else {
+		iov[0].iov_len = (sb->sb_data + sb->sb_datalen) - sb->sb_rptr;
+		if (iov[0].iov_len > len) iov[0].iov_len = len;
+		len -= iov[0].iov_len;
+		if (len) {
+			iov[1].iov_base = sb->sb_data;
+			iov[1].iov_len = sb->sb_wptr - sb->sb_data;
+			if (iov[1].iov_len > len) iov[1].iov_len = len;
+			n = 2;
+		} else
+			n = 1;
+	}
+	/* Check if there's urgent data to send, and if so, send it */
+
+#ifdef HAVE_READV
+	nn = writev(so->s, (const struct iovec *)iov, n);
+
+	DEBUG_MISC((dfd, "  ... wrote nn = %d bytes\n", nn));
+#else
+	nn = slirp_send(so, iov[0].iov_base, iov[0].iov_len,0);
+#endif
+	/* This should never happen, but people tell me it does *shrug* */
+	if (nn < 0 && (errno == EAGAIN || errno == EINTR))
+		return 0;
+
+	if (nn <= 0) {
+		DEBUG_MISC((dfd, " --- sowrite disconnected, so->so_state = %x, errno = %d\n",
+			so->so_state, errno));
+		sofcantsendmore(so);
+		tcp_sockclosed(sototcpcb(so));
+		return -1;
+	}
+
+#ifndef HAVE_READV
+	if (n == 2 && nn == iov[0].iov_len) {
+            int ret;
+            ret = slirp_send(so, iov[1].iov_base, iov[1].iov_len,0);
+            if (ret > 0)
+                nn += ret;
+        }
+        DEBUG_MISC((dfd, "  ... wrote nn = %d bytes\n", nn));
+#endif
+
+	/* Update sbuf */
+	sb->sb_cc -= nn;
+	sb->sb_rptr += nn;
+	if (sb->sb_rptr >= (sb->sb_data + sb->sb_datalen))
+		sb->sb_rptr -= sb->sb_datalen;
+
+	/*
+	 * If in DRAIN mode, and there's no more data, set
+	 * it CANTSENDMORE
+	 */
+	if ((so->so_state & SS_FWDRAIN) && sb->sb_cc == 0)
+		sofcantsendmore(so);
+
+	return nn;
+}
+
+/*
+ * recvfrom() a UDP socket
+ */
+void
+sorecvfrom(struct socket *so)
+{
+	struct sockaddr_in addr;
+	socklen_t addrlen = sizeof(struct sockaddr_in);
+
+	DEBUG_CALL("sorecvfrom");
+	DEBUG_ARG("so = %p", so);
+
+	if (so->so_type == IPPROTO_ICMP) {   /* This is a "ping" reply */
+	  char buff[256];
+	  int len;
+
+	  len = recvfrom(so->s, buff, 256, 0,
+			 (struct sockaddr *)&addr, &addrlen);
+	  /* XXX Check if reply is "correct"? */
+
+	  if(len == -1 || len == 0) {
+	    u_char code=ICMP_UNREACH_PORT;
+
+	    if(errno == EHOSTUNREACH) code=ICMP_UNREACH_HOST;
+	    else if(errno == ENETUNREACH) code=ICMP_UNREACH_NET;
+
+	    DEBUG_MISC((dfd," udp icmp rx errno = %d-%s\n",
+			errno,strerror(errno)));
+	    icmp_error(so->so_m, ICMP_UNREACH,code, 0,strerror(errno));
+	  } else {
+	    icmp_reflect(so->so_m);
+            so->so_m = NULL; /* Don't m_free() it again! */
+	  }
+	  /* No need for this socket anymore, udp_detach it */
+	  udp_detach(so);
+	} else {                            	/* A "normal" UDP packet */
+	  struct mbuf *m;
+          int len;
+#ifdef _WIN32
+          unsigned long n;
+#else
+          int n;
+#endif
+
+	  m = m_get(so->slirp);
+	  if (!m) {
+	      return;
+	  }
+	  m->m_data += IF_MAXLINKHDR;
+
+	  /*
+	   * XXX Shouldn't FIONREAD packets destined for port 53,
+	   * but I don't know the max packet size for DNS lookups
+	   */
+	  len = M_FREEROOM(m);
+	  /* if (so->so_fport != htons(53)) { */
+	  ioctlsocket(so->s, FIONREAD, &n);
+
+	  if (n > len) {
+	    n = (m->m_data - m->m_dat) + m->m_len + n + 1;
+	    m_inc(m, n);
+	    len = M_FREEROOM(m);
+	  }
+	  /* } */
+
+	  m->m_len = recvfrom(so->s, m->m_data, len, 0,
+			      (struct sockaddr *)&addr, &addrlen);
+	  DEBUG_MISC((dfd, " did recvfrom %d, errno = %d-%s\n",
+		      m->m_len, errno,strerror(errno)));
+	  if(m->m_len<0) {
+	    u_char code=ICMP_UNREACH_PORT;
+
+	    if(errno == EHOSTUNREACH) code=ICMP_UNREACH_HOST;
+	    else if(errno == ENETUNREACH) code=ICMP_UNREACH_NET;
+
+	    DEBUG_MISC((dfd," rx error, tx icmp ICMP_UNREACH:%i\n", code));
+	    icmp_error(so->so_m, ICMP_UNREACH,code, 0,strerror(errno));
+	    m_free(m);
+	  } else {
+	  /*
+	   * Hack: domain name lookup will be used the most for UDP,
+	   * and since they'll only be used once there's no need
+	   * for the 4 minute (or whatever) timeout... So we time them
+	   * out much quicker (10 seconds  for now...)
+	   */
+	    if (so->so_expire) {
+	      if (so->so_fport == htons(53))
+		so->so_expire = curtime + SO_EXPIREFAST;
+	      else
+		so->so_expire = curtime + SO_EXPIRE;
+	    }
+
+	    /*
+	     * If this packet was destined for CTL_ADDR,
+	     * make it look like that's where it came from, done by udp_output
+	     */
+	    udp_output(so, m, &addr);
+	  } /* rx error */
+	} /* if ping packet */
+}
+
+/*
+ * sendto() a socket
+ */
+int
+sosendto(struct socket *so, struct mbuf *m)
+{
+	Slirp *slirp = so->slirp;
+	int ret;
+	struct sockaddr_in addr;
+
+	DEBUG_CALL("sosendto");
+	DEBUG_ARG("so = %p", so);
+	DEBUG_ARG("m = %p", m);
+
+        addr.sin_family = AF_INET;
+	if ((so->so_faddr.s_addr & slirp->vnetwork_mask.s_addr) ==
+	    slirp->vnetwork_addr.s_addr) {
+	  /* It's an alias */
+	  if (so->so_faddr.s_addr == slirp->vnameserver_addr.s_addr) {
+	    if (get_dns_addr(&addr.sin_addr) < 0)
+	      addr.sin_addr = loopback_addr;
+	  } else {
+	    addr.sin_addr = loopback_addr;
+	  }
+	} else
+	  addr.sin_addr = so->so_faddr;
+	addr.sin_port = so->so_fport;
+
+	DEBUG_MISC((dfd, " sendto()ing, addr.sin_port=%d, addr.sin_addr.s_addr=%.16s\n", ntohs(addr.sin_port), inet_ntoa(addr.sin_addr)));
+
+	/* Don't care what port we get */
+	ret = sendto(so->s, m->m_data, m->m_len, 0,
+		     (struct sockaddr *)&addr, sizeof (struct sockaddr));
+	if (ret < 0)
+		return -1;
+
+	/*
+	 * Kill the socket if there's no reply in 4 minutes,
+	 * but only if it's an expirable socket
+	 */
+	if (so->so_expire)
+		so->so_expire = curtime + SO_EXPIRE;
+	so->so_state &= SS_PERSISTENT_MASK;
+	so->so_state |= SS_ISFCONNECTED; /* So that it gets select()ed */
+	return 0;
+}
+
+/*
+ * Listen for incoming TCP connections
+ */
+struct socket *
+tcp_listen(Slirp *slirp, uint32_t haddr, u_int hport, uint32_t laddr,
+           u_int lport, int flags)
+{
+	struct sockaddr_in addr;
+	struct socket *so;
+	int s, opt = 1;
+	socklen_t addrlen = sizeof(addr);
+	memset(&addr, 0, addrlen);
+
+	DEBUG_CALL("tcp_listen");
+	DEBUG_ARG("haddr = %x", haddr);
+	DEBUG_ARG("hport = %d", hport);
+	DEBUG_ARG("laddr = %x", laddr);
+	DEBUG_ARG("lport = %d", lport);
+	DEBUG_ARG("flags = %x", flags);
+
+	so = socreate(slirp);
+	if (!so) {
+	  return NULL;
+	}
+
+	/* Don't tcp_attach... we don't need so_snd nor so_rcv */
+	if ((so->so_tcpcb = tcp_newtcpcb(so)) == NULL) {
+		free(so);
+		return NULL;
+	}
+	insque(so, &slirp->tcb);
+
+	/*
+	 * SS_FACCEPTONCE sockets must time out.
+	 */
+	if (flags & SS_FACCEPTONCE)
+	   so->so_tcpcb->t_timer[TCPT_KEEP] = TCPTV_KEEP_INIT*2;
+
+	so->so_state &= SS_PERSISTENT_MASK;
+	so->so_state |= (SS_FACCEPTCONN | flags);
+	so->so_lport = lport; /* Kept in network format */
+	so->so_laddr.s_addr = laddr; /* Ditto */
+
+	addr.sin_family = AF_INET;
+	addr.sin_addr.s_addr = haddr;
+	addr.sin_port = hport;
+
+	if (((s = qemu_socket(AF_INET,SOCK_STREAM,0)) < 0) ||
+	    (socket_set_fast_reuse(s) < 0) ||
+	    (bind(s,(struct sockaddr *)&addr, sizeof(addr)) < 0) ||
+	    (listen(s,1) < 0)) {
+		int tmperrno = errno; /* Don't clobber the real reason we failed */
+
+		close(s);
+		sofree(so);
+		/* Restore the real errno */
+#ifdef _WIN32
+		WSASetLastError(tmperrno);
+#else
+		errno = tmperrno;
+#endif
+		return NULL;
+	}
+	qemu_setsockopt(s, SOL_SOCKET, SO_OOBINLINE, &opt, sizeof(int));
+
+	getsockname(s,(struct sockaddr *)&addr,&addrlen);
+	so->so_fport = addr.sin_port;
+	if (addr.sin_addr.s_addr == 0 || addr.sin_addr.s_addr == loopback_addr.s_addr)
+	   so->so_faddr = slirp->vhost_addr;
+	else
+	   so->so_faddr = addr.sin_addr;
+
+	so->s = s;
+	return so;
+}
+
+/*
+ * Various session state calls
+ * XXX Should be #define's
+ * The socket state stuff needs work, these often get call 2 or 3
+ * times each when only 1 was needed
+ */
+void
+soisfconnecting(struct socket *so)
+{
+	so->so_state &= ~(SS_NOFDREF|SS_ISFCONNECTED|SS_FCANTRCVMORE|
+			  SS_FCANTSENDMORE|SS_FWDRAIN);
+	so->so_state |= SS_ISFCONNECTING; /* Clobber other states */
+}
+
+void
+soisfconnected(struct socket *so)
+{
+	so->so_state &= ~(SS_ISFCONNECTING|SS_FWDRAIN|SS_NOFDREF);
+	so->so_state |= SS_ISFCONNECTED; /* Clobber other states */
+}
+
+static void
+sofcantrcvmore(struct socket *so)
+{
+	if ((so->so_state & SS_NOFDREF) == 0) {
+		shutdown(so->s,0);
+	}
+	so->so_state &= ~(SS_ISFCONNECTING);
+	if (so->so_state & SS_FCANTSENDMORE) {
+	   so->so_state &= SS_PERSISTENT_MASK;
+	   so->so_state |= SS_NOFDREF; /* Don't select it */
+	} else {
+	   so->so_state |= SS_FCANTRCVMORE;
+	}
+}
+
+static void
+sofcantsendmore(struct socket *so)
+{
+	if ((so->so_state & SS_NOFDREF) == 0) {
+            shutdown(so->s,1);           /* send FIN to fhost */
+	}
+	so->so_state &= ~(SS_ISFCONNECTING);
+	if (so->so_state & SS_FCANTRCVMORE) {
+	   so->so_state &= SS_PERSISTENT_MASK;
+	   so->so_state |= SS_NOFDREF; /* as above */
+	} else {
+	   so->so_state |= SS_FCANTSENDMORE;
+	}
+}
+
+/*
+ * Set write drain mode
+ * Set CANTSENDMORE once all data has been write()n
+ */
+void
+sofwdrain(struct socket *so)
+{
+	if (so->so_rcv.sb_cc)
+		so->so_state |= SS_FWDRAIN;
+	else
+		sofcantsendmore(so);
+}
diff --git a/src/slirp/socket.h b/src/slirp/socket.h
new file mode 100644
index 0000000..57e0407
--- /dev/null
+++ b/src/slirp/socket.h
@@ -0,0 +1,97 @@
+/*
+ * Copyright (c) 1995 Danny Gasparovski.
+ *
+ * Please read the file COPYRIGHT for the
+ * terms and conditions of the copyright.
+ */
+
+#ifndef _SLIRP_SOCKET_H_
+#define _SLIRP_SOCKET_H_
+
+#define SO_EXPIRE 240000
+#define SO_EXPIREFAST 10000
+
+/*
+ * Our socket structure
+ */
+
+struct socket {
+  struct socket *so_next,*so_prev;      /* For a linked list of sockets */
+
+  int s;                           /* The actual socket */
+
+  int pollfds_idx;                 /* GPollFD GArray index */
+
+  Slirp *slirp;			   /* managing slirp instance */
+
+			/* XXX union these with not-yet-used sbuf params */
+  struct mbuf *so_m;	           /* Pointer to the original SYN packet,
+				    * for non-blocking connect()'s, and
+				    * PING reply's */
+  struct tcpiphdr *so_ti;	   /* Pointer to the original ti within
+				    * so_mconn, for non-blocking connections */
+  int so_urgc;
+  struct in_addr so_faddr;	   /* foreign host table entry */
+  struct in_addr so_laddr;	   /* local host table entry */
+  uint16_t so_fport;		   /* foreign port */
+  uint16_t so_lport;		   /* local port */
+
+  uint8_t	so_iptos;	/* Type of service */
+  uint8_t	so_emu;		/* Is the socket emulated? */
+
+  u_char	so_type;		/* Type of socket, UDP or TCP */
+  int	so_state;		/* internal state flags SS_*, below */
+
+  struct 	tcpcb *so_tcpcb;	/* pointer to TCP protocol control block */
+  u_int	so_expire;		/* When the socket will expire */
+
+  int	so_queued;		/* Number of packets queued from this socket */
+  int	so_nqueued;		/* Number of packets queued in a row
+				 * Used to determine when to "downgrade" a session
+					 * from fastq to batchq */
+
+  struct sbuf so_rcv;		/* Receive buffer */
+  struct sbuf so_snd;		/* Send buffer */
+  void * extra;			/* Extra pointer */
+};
+
+
+/*
+ * Socket state bits. (peer means the host on the Internet,
+ * local host means the host on the other end of the modem)
+ */
+#define SS_NOFDREF		0x001	/* No fd reference */
+
+#define SS_ISFCONNECTING	0x002	/* Socket is connecting to peer (non-blocking connect()'s) */
+#define SS_ISFCONNECTED		0x004	/* Socket is connected to peer */
+#define SS_FCANTRCVMORE		0x008	/* Socket can't receive more from peer (for half-closes) */
+#define SS_FCANTSENDMORE	0x010	/* Socket can't send more to peer (for half-closes) */
+#define SS_FWDRAIN		0x040	/* We received a FIN, drain data and set SS_FCANTSENDMORE */
+
+#define SS_CTL			0x080
+#define SS_FACCEPTCONN		0x100	/* Socket is accepting connections from a host on the internet */
+#define SS_FACCEPTONCE		0x200	/* If set, the SS_FACCEPTCONN socket will die after one accept */
+
+#define SS_PERSISTENT_MASK	0xf000	/* Unremovable state bits */
+#define SS_HOSTFWD		0x1000	/* Socket describes host->guest forwarding */
+#define SS_INCOMING		0x2000	/* Connection was initiated by a host on the internet */
+
+struct socket * solookup(struct socket *, struct in_addr, u_int, struct in_addr, u_int);
+struct socket * socreate(Slirp *);
+void sofree(struct socket *);
+int soread(struct socket *);
+void sorecvoob(struct socket *);
+int sosendoob(struct socket *);
+int sowrite(struct socket *);
+void sorecvfrom(struct socket *);
+int sosendto(struct socket *, struct mbuf *);
+struct socket * tcp_listen(Slirp *, uint32_t, u_int, uint32_t, u_int,
+                               int);
+void soisfconnecting(register struct socket *);
+void soisfconnected(register struct socket *);
+void sofwdrain(struct socket *);
+struct iovec; /* For win32 */
+size_t sopreprbuf(struct socket *so, struct iovec *iov, int *np);
+int soreadbuf(struct socket *so, const char *buf, int size);
+
+#endif /* _SOCKET_H_ */
diff --git a/src/slirp/tcp.h b/src/slirp/tcp.h
new file mode 100644
index 0000000..2e2b403
--- /dev/null
+++ b/src/slirp/tcp.h
@@ -0,0 +1,176 @@
+/*
+ * Copyright (c) 1982, 1986, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)tcp.h	8.1 (Berkeley) 6/10/93
+ * tcp.h,v 1.3 1994/08/21 05:27:34 paul Exp
+ */
+
+#ifndef _TCP_H_
+#define _TCP_H_
+
+typedef	uint32_t tcp_seq;
+
+#define      PR_SLOWHZ       2               /* 2 slow timeouts per second (approx) */
+#define      PR_FASTHZ       5               /* 5 fast timeouts per second (not important) */
+
+#define TCP_SNDSPACE 8192
+#define TCP_RCVSPACE 8192
+
+/*
+ * TCP header.
+ * Per RFC 793, September, 1981.
+ */
+#define tcphdr slirp_tcphdr
+struct tcphdr {
+	uint16_t th_sport;              /* source port */
+	uint16_t th_dport;              /* destination port */
+	tcp_seq	th_seq;			/* sequence number */
+	tcp_seq	th_ack;			/* acknowledgement number */
+#ifdef HOST_WORDS_BIGENDIAN
+	uint8_t	th_off:4,		/* data offset */
+		th_x2:4;		/* (unused) */
+#else
+	uint8_t	th_x2:4,		/* (unused) */
+		th_off:4;		/* data offset */
+#endif
+	uint8_t th_flags;
+	uint16_t th_win;                /* window */
+	uint16_t th_sum;                /* checksum */
+	uint16_t th_urp;                /* urgent pointer */
+};
+
+#include "tcp_var.h"
+
+#ifndef TH_FIN
+#define	TH_FIN	0x01
+#define	TH_SYN	0x02
+#define	TH_RST	0x04
+#define	TH_PUSH	0x08
+#define	TH_ACK	0x10
+#define	TH_URG	0x20
+#endif
+
+#ifndef TCPOPT_EOL
+#define	TCPOPT_EOL		0
+#define	TCPOPT_NOP		1
+#define	TCPOPT_MAXSEG		2
+#define TCPOPT_WINDOW		3
+#define TCPOPT_SACK_PERMITTED	4		/* Experimental */
+#define TCPOPT_SACK		5		/* Experimental */
+#define TCPOPT_TIMESTAMP	8
+
+#define TCPOPT_TSTAMP_HDR	\
+    (TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_TIMESTAMP<<8|TCPOLEN_TIMESTAMP)
+#endif
+
+#ifndef TCPOLEN_MAXSEG
+#define    TCPOLEN_MAXSEG		4
+#define    TCPOLEN_WINDOW		3
+#define    TCPOLEN_SACK_PERMITTED	2
+#define    TCPOLEN_TIMESTAMP		10
+#define    TCPOLEN_TSTAMP_APPA		(TCPOLEN_TIMESTAMP+2) /* appendix A */
+#endif
+
+/*
+ * Default maximum segment size for TCP.
+ * With an IP MSS of 576, this is 536,
+ * but 512 is probably more convenient.
+ * This should be defined as MIN(512, IP_MSS - sizeof (struct tcpiphdr)).
+ *
+ * We make this 1460 because we only care about Ethernet in the qemu context.
+ */
+#undef TCP_MSS
+#define	TCP_MSS	1460
+
+#undef TCP_MAXWIN
+#define	TCP_MAXWIN	65535	/* largest value for (unscaled) window */
+
+#undef TCP_MAX_WINSHIFT
+#define TCP_MAX_WINSHIFT	14	/* maximum window shift */
+
+/*
+ * User-settable options (used with setsockopt).
+ *
+ * We don't use the system headers on unix because we have conflicting
+ * local structures. We can't avoid the system definitions on Windows,
+ * so we undefine them.
+ */
+#undef TCP_NODELAY
+#define	TCP_NODELAY	0x01	/* don't delay send to coalesce packets */
+#undef TCP_MAXSEG
+
+/*
+ * TCP FSM state definitions.
+ * Per RFC793, September, 1981.
+ */
+
+#define TCP_NSTATES     11
+
+#define TCPS_CLOSED             0       /* closed */
+#define TCPS_LISTEN             1       /* listening for connection */
+#define TCPS_SYN_SENT           2       /* active, have sent syn */
+#define TCPS_SYN_RECEIVED       3       /* have send and received syn */
+/* states < TCPS_ESTABLISHED are those where connections not established */
+#define TCPS_ESTABLISHED        4       /* established */
+#define TCPS_CLOSE_WAIT         5       /* rcvd fin, waiting for close */
+/* states > TCPS_CLOSE_WAIT are those where user has closed */
+#define TCPS_FIN_WAIT_1         6       /* have closed, sent fin */
+#define TCPS_CLOSING            7       /* closed xchd FIN; await FIN ACK */
+#define TCPS_LAST_ACK           8       /* had fin and close; await FIN ACK */
+/* states > TCPS_CLOSE_WAIT && < TCPS_FIN_WAIT_2 await ACK of FIN */
+#define TCPS_FIN_WAIT_2         9       /* have closed, fin is acked */
+#define TCPS_TIME_WAIT          10      /* in 2*msl quiet wait after close */
+
+#define TCPS_HAVERCVDSYN(s)     ((s) >= TCPS_SYN_RECEIVED)
+#define TCPS_HAVEESTABLISHED(s) ((s) >= TCPS_ESTABLISHED)
+#define TCPS_HAVERCVDFIN(s)     ((s) >= TCPS_TIME_WAIT)
+
+/*
+ * TCP sequence numbers are 32 bit integers operated
+ * on with modular arithmetic.  These macros can be
+ * used to compare such integers.
+ */
+#define SEQ_LT(a,b)     ((int)((a)-(b)) < 0)
+#define SEQ_LEQ(a,b)    ((int)((a)-(b)) <= 0)
+#define SEQ_GT(a,b)     ((int)((a)-(b)) > 0)
+#define SEQ_GEQ(a,b)    ((int)((a)-(b)) >= 0)
+
+/*
+ * Macros to initialize tcp sequence numbers for
+ * send and receive from initial send and receive
+ * sequence numbers.
+ */
+#define tcp_rcvseqinit(tp) \
+     (tp)->rcv_adv = (tp)->rcv_nxt = (tp)->irs + 1
+
+#define tcp_sendseqinit(tp) \
+    (tp)->snd_una = (tp)->snd_nxt = (tp)->snd_max = (tp)->snd_up = (tp)->iss
+
+#define TCP_ISSINCR     (125*1024)      /* increment for tcp_iss each second */
+
+#endif
diff --git a/src/slirp/tcp_input.c b/src/slirp/tcp_input.c
new file mode 100644
index 0000000..6b096ec
--- /dev/null
+++ b/src/slirp/tcp_input.c
@@ -0,0 +1,1496 @@
+/*
+ * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1994
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)tcp_input.c	8.5 (Berkeley) 4/10/94
+ * tcp_input.c,v 1.10 1994/10/13 18:36:32 wollman Exp
+ */
+
+/*
+ * Changes and additions relating to SLiRP
+ * Copyright (c) 1995 Danny Gasparovski.
+ *
+ * Please read the file COPYRIGHT for the
+ * terms and conditions of the copyright.
+ */
+
+#include <slirp.h>
+#include "ip_icmp.h"
+
+#define	TCPREXMTTHRESH 3
+
+#define TCP_PAWS_IDLE	(24 * 24 * 60 * 60 * PR_SLOWHZ)
+
+/* for modulo comparisons of timestamps */
+#define TSTMP_LT(a,b)	((int)((a)-(b)) < 0)
+#define TSTMP_GEQ(a,b)	((int)((a)-(b)) >= 0)
+
+/*
+ * Insert segment ti into reassembly queue of tcp with
+ * control block tp.  Return TH_FIN if reassembly now includes
+ * a segment with FIN.  The macro form does the common case inline
+ * (segment is the next to be received on an established connection,
+ * and the queue is empty), avoiding linkage into and removal
+ * from the queue and repetition of various conversions.
+ * Set DELACK for segments received in order, but ack immediately
+ * when segments are out of order (so fast retransmit can work).
+ */
+#ifdef TCP_ACK_HACK
+#define TCP_REASS(tp, ti, m, so, flags) {\
+       if ((ti)->ti_seq == (tp)->rcv_nxt && \
+           tcpfrag_list_empty(tp) && \
+           (tp)->t_state == TCPS_ESTABLISHED) {\
+               if (ti->ti_flags & TH_PUSH) \
+                       tp->t_flags |= TF_ACKNOW; \
+               else \
+                       tp->t_flags |= TF_DELACK; \
+               (tp)->rcv_nxt += (ti)->ti_len; \
+               flags = (ti)->ti_flags & TH_FIN; \
+               if (so->so_emu) { \
+		       if (tcp_emu((so),(m))) sbappend((so), (m)); \
+	       } else \
+	       	       sbappend((so), (m)); \
+	} else {\
+               (flags) = tcp_reass((tp), (ti), (m)); \
+               tp->t_flags |= TF_ACKNOW; \
+       } \
+}
+#else
+#define	TCP_REASS(tp, ti, m, so, flags) { \
+	if ((ti)->ti_seq == (tp)->rcv_nxt && \
+        tcpfrag_list_empty(tp) && \
+	    (tp)->t_state == TCPS_ESTABLISHED) { \
+		tp->t_flags |= TF_DELACK; \
+		(tp)->rcv_nxt += (ti)->ti_len; \
+		flags = (ti)->ti_flags & TH_FIN; \
+		if (so->so_emu) { \
+			if (tcp_emu((so),(m))) sbappend(so, (m)); \
+		} else \
+			sbappend((so), (m)); \
+	} else { \
+		(flags) = tcp_reass((tp), (ti), (m)); \
+		tp->t_flags |= TF_ACKNOW; \
+	} \
+}
+#endif
+static void tcp_dooptions(struct tcpcb *tp, u_char *cp, int cnt,
+                          struct tcpiphdr *ti);
+static void tcp_xmit_timer(register struct tcpcb *tp, int rtt);
+
+static int
+tcp_reass(register struct tcpcb *tp, register struct tcpiphdr *ti,
+          struct mbuf *m)
+{
+	register struct tcpiphdr *q;
+	struct socket *so = tp->t_socket;
+	int flags;
+
+	/*
+	 * Call with ti==NULL after become established to
+	 * force pre-ESTABLISHED data up to user socket.
+	 */
+        if (ti == NULL)
+		goto present;
+
+	/*
+	 * Find a segment which begins after this one does.
+	 */
+	for (q = tcpfrag_list_first(tp); !tcpfrag_list_end(q, tp);
+            q = tcpiphdr_next(q))
+		if (SEQ_GT(q->ti_seq, ti->ti_seq))
+			break;
+
+	/*
+	 * If there is a preceding segment, it may provide some of
+	 * our data already.  If so, drop the data from the incoming
+	 * segment.  If it provides all of our data, drop us.
+	 */
+	if (!tcpfrag_list_end(tcpiphdr_prev(q), tp)) {
+		register int i;
+		q = tcpiphdr_prev(q);
+		/* conversion to int (in i) handles seq wraparound */
+		i = q->ti_seq + q->ti_len - ti->ti_seq;
+		if (i > 0) {
+			if (i >= ti->ti_len) {
+				m_free(m);
+				/*
+				 * Try to present any queued data
+				 * at the left window edge to the user.
+				 * This is needed after the 3-WHS
+				 * completes.
+				 */
+				goto present;   /* ??? */
+			}
+			m_adj(m, i);
+			ti->ti_len -= i;
+			ti->ti_seq += i;
+		}
+		q = tcpiphdr_next(q);
+	}
+	ti->ti_mbuf = m;
+
+	/*
+	 * While we overlap succeeding segments trim them or,
+	 * if they are completely covered, dequeue them.
+	 */
+	while (!tcpfrag_list_end(q, tp)) {
+		register int i = (ti->ti_seq + ti->ti_len) - q->ti_seq;
+		if (i <= 0)
+			break;
+		if (i < q->ti_len) {
+			q->ti_seq += i;
+			q->ti_len -= i;
+			m_adj(q->ti_mbuf, i);
+			break;
+		}
+		q = tcpiphdr_next(q);
+		m = tcpiphdr_prev(q)->ti_mbuf;
+		remque(tcpiphdr2qlink(tcpiphdr_prev(q)));
+		m_free(m);
+	}
+
+	/*
+	 * Stick new segment in its place.
+	 */
+	insque(tcpiphdr2qlink(ti), tcpiphdr2qlink(tcpiphdr_prev(q)));
+
+present:
+	/*
+	 * Present data to user, advancing rcv_nxt through
+	 * completed sequence space.
+	 */
+	if (!TCPS_HAVEESTABLISHED(tp->t_state))
+		return (0);
+	ti = tcpfrag_list_first(tp);
+	if (tcpfrag_list_end(ti, tp) || ti->ti_seq != tp->rcv_nxt)
+		return (0);
+	if (tp->t_state == TCPS_SYN_RECEIVED && ti->ti_len)
+		return (0);
+	do {
+		tp->rcv_nxt += ti->ti_len;
+		flags = ti->ti_flags & TH_FIN;
+		remque(tcpiphdr2qlink(ti));
+		m = ti->ti_mbuf;
+		ti = tcpiphdr_next(ti);
+		if (so->so_state & SS_FCANTSENDMORE)
+			m_free(m);
+		else {
+			if (so->so_emu) {
+				if (tcp_emu(so,m)) sbappend(so, m);
+			} else
+				sbappend(so, m);
+		}
+	} while (ti != (struct tcpiphdr *)tp && ti->ti_seq == tp->rcv_nxt);
+	return (flags);
+}
+
+/*
+ * TCP input routine, follows pages 65-76 of the
+ * protocol specification dated September, 1981 very closely.
+ */
+void
+tcp_input(struct mbuf *m, int iphlen, struct socket *inso)
+{
+  	struct ip save_ip, *ip;
+	register struct tcpiphdr *ti;
+	caddr_t optp = NULL;
+	int optlen = 0;
+	int len, tlen, off;
+        register struct tcpcb *tp = NULL;
+	register int tiflags;
+        struct socket *so = NULL;
+	int todrop, acked, ourfinisacked, needoutput = 0;
+	int iss = 0;
+	u_long tiwin;
+	int ret;
+    struct ex_list *ex_ptr;
+    Slirp *slirp;
+
+	DEBUG_CALL("tcp_input");
+	DEBUG_ARGS((dfd, " m = %p  iphlen = %2d  inso = %p\n",
+		    m, iphlen, inso));
+
+	/*
+	 * If called with m == 0, then we're continuing the connect
+	 */
+	if (m == NULL) {
+		so = inso;
+		slirp = so->slirp;
+
+		/* Re-set a few variables */
+		tp = sototcpcb(so);
+		m = so->so_m;
+                so->so_m = NULL;
+		ti = so->so_ti;
+		tiwin = ti->ti_win;
+		tiflags = ti->ti_flags;
+
+		goto cont_conn;
+	}
+	slirp = m->slirp;
+
+	/*
+	 * Get IP and TCP header together in first mbuf.
+	 * Note: IP leaves IP header in first mbuf.
+	 */
+	ti = mtod(m, struct tcpiphdr *);
+	if (iphlen > sizeof(struct ip )) {
+	  ip_stripoptions(m, (struct mbuf *)0);
+	  iphlen=sizeof(struct ip );
+	}
+	/* XXX Check if too short */
+
+
+	/*
+	 * Save a copy of the IP header in case we want restore it
+	 * for sending an ICMP error message in response.
+	 */
+	ip=mtod(m, struct ip *);
+	save_ip = *ip;
+	save_ip.ip_len+= iphlen;
+
+	/*
+	 * Checksum extended TCP header and data.
+	 */
+	tlen = ((struct ip *)ti)->ip_len;
+        tcpiphdr2qlink(ti)->next = tcpiphdr2qlink(ti)->prev = NULL;
+        memset(&ti->ti_i.ih_mbuf, 0 , sizeof(struct mbuf_ptr));
+	ti->ti_x1 = 0;
+	ti->ti_len = htons((uint16_t)tlen);
+	len = sizeof(struct ip ) + tlen;
+	if(cksum(m, len)) {
+	  goto drop;
+	}
+
+	/*
+	 * Check that TCP offset makes sense,
+	 * pull out TCP options and adjust length.		XXX
+	 */
+	off = ti->ti_off << 2;
+	if (off < sizeof (struct tcphdr) || off > tlen) {
+	  goto drop;
+	}
+	tlen -= off;
+	ti->ti_len = tlen;
+	if (off > sizeof (struct tcphdr)) {
+	  optlen = off - sizeof (struct tcphdr);
+	  optp = mtod(m, caddr_t) + sizeof (struct tcpiphdr);
+	}
+	tiflags = ti->ti_flags;
+
+	/*
+	 * Convert TCP protocol specific fields to host format.
+	 */
+	NTOHL(ti->ti_seq);
+	NTOHL(ti->ti_ack);
+	NTOHS(ti->ti_win);
+	NTOHS(ti->ti_urp);
+
+	/*
+	 * Drop TCP, IP headers and TCP options.
+	 */
+	m->m_data += sizeof(struct tcpiphdr)+off-sizeof(struct tcphdr);
+	m->m_len  -= sizeof(struct tcpiphdr)+off-sizeof(struct tcphdr);
+
+	/*
+	 * Locate pcb for segment.
+	 */
+findso:
+	so = slirp->tcp_last_so;
+	if (so->so_fport != ti->ti_dport ||
+	    so->so_lport != ti->ti_sport ||
+	    so->so_laddr.s_addr != ti->ti_src.s_addr ||
+	    so->so_faddr.s_addr != ti->ti_dst.s_addr) {
+		so = solookup(&slirp->tcb, ti->ti_src, ti->ti_sport,
+			       ti->ti_dst, ti->ti_dport);
+		if (so)
+			slirp->tcp_last_so = so;
+	}
+
+	/*
+	 * If the state is CLOSED (i.e., TCB does not exist) then
+	 * all data in the incoming segment is discarded.
+	 * If the TCB exists but is in CLOSED state, it is embryonic,
+	 * but should either do a listen or a connect soon.
+	 *
+	 * state == CLOSED means we've done socreate() but haven't
+	 * attached it to a protocol yet...
+	 *
+	 * XXX If a TCB does not exist, and the TH_SYN flag is
+	 * the only flag set, then create a session, mark it
+	 * as if it was LISTENING, and continue...
+	 */
+        if (so == NULL) {
+          if (slirp->restricted) {
+            /* Any hostfwds will have an existing socket, so we only get here
+             * for non-hostfwd connections. These should be dropped, unless it
+             * happens to be a guestfwd.
+             */
+            for (ex_ptr = slirp->exec_list; ex_ptr; ex_ptr = ex_ptr->ex_next) {
+                if (ex_ptr->ex_fport == ti->ti_dport &&
+                    ti->ti_dst.s_addr == ex_ptr->ex_addr.s_addr) {
+                    break;
+                }
+            }
+            if (!ex_ptr) {
+                goto dropwithreset;
+            }
+          }
+
+	  if ((tiflags & (TH_SYN|TH_FIN|TH_RST|TH_URG|TH_ACK)) != TH_SYN)
+	    goto dropwithreset;
+
+	  if ((so = socreate(slirp)) == NULL)
+	    goto dropwithreset;
+	  if (tcp_attach(so) < 0) {
+	    free(so); /* Not sofree (if it failed, it's not insqued) */
+	    goto dropwithreset;
+	  }
+
+	  sbreserve(&so->so_snd, TCP_SNDSPACE);
+	  sbreserve(&so->so_rcv, TCP_RCVSPACE);
+
+	  so->so_laddr = ti->ti_src;
+	  so->so_lport = ti->ti_sport;
+	  so->so_faddr = ti->ti_dst;
+	  so->so_fport = ti->ti_dport;
+
+	  if ((so->so_iptos = tcp_tos(so)) == 0)
+	    so->so_iptos = ((struct ip *)ti)->ip_tos;
+
+	  tp = sototcpcb(so);
+	  tp->t_state = TCPS_LISTEN;
+	}
+
+        /*
+         * If this is a still-connecting socket, this probably
+         * a retransmit of the SYN.  Whether it's a retransmit SYN
+	 * or something else, we nuke it.
+         */
+        if (so->so_state & SS_ISFCONNECTING)
+                goto drop;
+
+	tp = sototcpcb(so);
+
+	/* XXX Should never fail */
+        if (tp == NULL)
+		goto dropwithreset;
+	if (tp->t_state == TCPS_CLOSED)
+		goto drop;
+
+	tiwin = ti->ti_win;
+
+	/*
+	 * Segment received on connection.
+	 * Reset idle time and keep-alive timer.
+	 */
+	tp->t_idle = 0;
+	if (SO_OPTIONS)
+	   tp->t_timer[TCPT_KEEP] = TCPTV_KEEPINTVL;
+	else
+	   tp->t_timer[TCPT_KEEP] = TCPTV_KEEP_IDLE;
+
+	/*
+	 * Process options if not in LISTEN state,
+	 * else do it below (after getting remote address).
+	 */
+	if (optp && tp->t_state != TCPS_LISTEN)
+		tcp_dooptions(tp, (u_char *)optp, optlen, ti);
+
+	/*
+	 * Header prediction: check for the two common cases
+	 * of a uni-directional data xfer.  If the packet has
+	 * no control flags, is in-sequence, the window didn't
+	 * change and we're not retransmitting, it's a
+	 * candidate.  If the length is zero and the ack moved
+	 * forward, we're the sender side of the xfer.  Just
+	 * free the data acked & wake any higher level process
+	 * that was blocked waiting for space.  If the length
+	 * is non-zero and the ack didn't move, we're the
+	 * receiver side.  If we're getting packets in-order
+	 * (the reassembly queue is empty), add the data to
+	 * the socket buffer and note that we need a delayed ack.
+	 *
+	 * XXX Some of these tests are not needed
+	 * eg: the tiwin == tp->snd_wnd prevents many more
+	 * predictions.. with no *real* advantage..
+	 */
+	if (tp->t_state == TCPS_ESTABLISHED &&
+	    (tiflags & (TH_SYN|TH_FIN|TH_RST|TH_URG|TH_ACK)) == TH_ACK &&
+	    ti->ti_seq == tp->rcv_nxt &&
+	    tiwin && tiwin == tp->snd_wnd &&
+	    tp->snd_nxt == tp->snd_max) {
+		if (ti->ti_len == 0) {
+			if (SEQ_GT(ti->ti_ack, tp->snd_una) &&
+			    SEQ_LEQ(ti->ti_ack, tp->snd_max) &&
+			    tp->snd_cwnd >= tp->snd_wnd) {
+				/*
+				 * this is a pure ack for outstanding data.
+				 */
+				if (tp->t_rtt &&
+				    SEQ_GT(ti->ti_ack, tp->t_rtseq))
+					tcp_xmit_timer(tp, tp->t_rtt);
+				acked = ti->ti_ack - tp->snd_una;
+				sbdrop(&so->so_snd, acked);
+				tp->snd_una = ti->ti_ack;
+				m_free(m);
+
+				/*
+				 * If all outstanding data are acked, stop
+				 * retransmit timer, otherwise restart timer
+				 * using current (possibly backed-off) value.
+				 * If process is waiting for space,
+				 * wakeup/selwakeup/signal.  If data
+				 * are ready to send, let tcp_output
+				 * decide between more output or persist.
+				 */
+				if (tp->snd_una == tp->snd_max)
+					tp->t_timer[TCPT_REXMT] = 0;
+				else if (tp->t_timer[TCPT_PERSIST] == 0)
+					tp->t_timer[TCPT_REXMT] = tp->t_rxtcur;
+
+				/*
+				 * This is called because sowwakeup might have
+				 * put data into so_snd.  Since we don't so sowwakeup,
+				 * we don't need this.. XXX???
+				 */
+				if (so->so_snd.sb_cc)
+					(void) tcp_output(tp);
+
+				return;
+			}
+		} else if (ti->ti_ack == tp->snd_una &&
+		    tcpfrag_list_empty(tp) &&
+		    ti->ti_len <= sbspace(&so->so_rcv)) {
+			/*
+			 * this is a pure, in-sequence data packet
+			 * with nothing on the reassembly queue and
+			 * we have enough buffer space to take it.
+			 */
+			tp->rcv_nxt += ti->ti_len;
+			/*
+			 * Add data to socket buffer.
+			 */
+			if (so->so_emu) {
+				if (tcp_emu(so,m)) sbappend(so, m);
+			} else
+				sbappend(so, m);
+
+			/*
+			 * If this is a short packet, then ACK now - with Nagel
+			 *	congestion avoidance sender won't send more until
+			 *	he gets an ACK.
+			 *
+			 * It is better to not delay acks at all to maximize
+			 * TCP throughput.  See RFC 2581.
+			 */
+			tp->t_flags |= TF_ACKNOW;
+			tcp_output(tp);
+			return;
+		}
+	} /* header prediction */
+	/*
+	 * Calculate amount of space in receive window,
+	 * and then do TCP input processing.
+	 * Receive window is amount of space in rcv queue,
+	 * but not less than advertised window.
+	 */
+	{ int win;
+          win = sbspace(&so->so_rcv);
+	  if (win < 0)
+	    win = 0;
+	  tp->rcv_wnd = max(win, (int)(tp->rcv_adv - tp->rcv_nxt));
+	}
+
+	switch (tp->t_state) {
+
+	/*
+	 * If the state is LISTEN then ignore segment if it contains an RST.
+	 * If the segment contains an ACK then it is bad and send a RST.
+	 * If it does not contain a SYN then it is not interesting; drop it.
+	 * Don't bother responding if the destination was a broadcast.
+	 * Otherwise initialize tp->rcv_nxt, and tp->irs, select an initial
+	 * tp->iss, and send a segment:
+	 *     <SEQ=ISS><ACK=RCV_NXT><CTL=SYN,ACK>
+	 * Also initialize tp->snd_nxt to tp->iss+1 and tp->snd_una to tp->iss.
+	 * Fill in remote peer address fields if not previously specified.
+	 * Enter SYN_RECEIVED state, and process any other fields of this
+	 * segment in this state.
+	 */
+	case TCPS_LISTEN: {
+
+	  if (tiflags & TH_RST)
+	    goto drop;
+	  if (tiflags & TH_ACK)
+	    goto dropwithreset;
+	  if ((tiflags & TH_SYN) == 0)
+	    goto drop;
+
+	  /*
+	   * This has way too many gotos...
+	   * But a bit of spaghetti code never hurt anybody :)
+	   */
+
+	  /*
+	   * If this is destined for the control address, then flag to
+	   * tcp_ctl once connected, otherwise connect
+	   */
+	  if ((so->so_faddr.s_addr & slirp->vnetwork_mask.s_addr) ==
+	      slirp->vnetwork_addr.s_addr) {
+	    if (so->so_faddr.s_addr != slirp->vhost_addr.s_addr &&
+		so->so_faddr.s_addr != slirp->vnameserver_addr.s_addr) {
+		/* May be an add exec */
+		for (ex_ptr = slirp->exec_list; ex_ptr;
+		     ex_ptr = ex_ptr->ex_next) {
+		  if(ex_ptr->ex_fport == so->so_fport &&
+		     so->so_faddr.s_addr == ex_ptr->ex_addr.s_addr) {
+		    so->so_state |= SS_CTL;
+		    break;
+		  }
+		}
+		if (so->so_state & SS_CTL) {
+		    goto cont_input;
+		}
+	    }
+	    /* CTL_ALIAS: Do nothing, tcp_fconnect will be called on it */
+	  }
+
+	  if (so->so_emu & EMU_NOCONNECT) {
+	    so->so_emu &= ~EMU_NOCONNECT;
+	    goto cont_input;
+	  }
+
+          if ((tcp_fconnect(so) == -1) &&
+#if defined(_WIN32)
+              socket_error() != WSAEWOULDBLOCK
+#else
+              (errno != EINPROGRESS) && (errno != EWOULDBLOCK)
+#endif
+          ) {
+	    u_char code=ICMP_UNREACH_NET;
+	    DEBUG_MISC((dfd, " tcp fconnect errno = %d-%s\n",
+			errno,strerror(errno)));
+	    if(errno == ECONNREFUSED) {
+	      /* ACK the SYN, send RST to refuse the connection */
+	      tcp_respond(tp, ti, m, ti->ti_seq+1, (tcp_seq)0,
+			  TH_RST|TH_ACK);
+	    } else {
+	      if(errno == EHOSTUNREACH) code=ICMP_UNREACH_HOST;
+	      HTONL(ti->ti_seq);             /* restore tcp header */
+	      HTONL(ti->ti_ack);
+	      HTONS(ti->ti_win);
+	      HTONS(ti->ti_urp);
+	      m->m_data -= sizeof(struct tcpiphdr)+off-sizeof(struct tcphdr);
+	      m->m_len  += sizeof(struct tcpiphdr)+off-sizeof(struct tcphdr);
+	      *ip=save_ip;
+	      icmp_error(m, ICMP_UNREACH,code, 0,strerror(errno));
+	    }
+            tcp_close(tp);
+	    m_free(m);
+	  } else {
+	    /*
+	     * Haven't connected yet, save the current mbuf
+	     * and ti, and return
+	     * XXX Some OS's don't tell us whether the connect()
+	     * succeeded or not.  So we must time it out.
+	     */
+	    so->so_m = m;
+	    so->so_ti = ti;
+	    tp->t_timer[TCPT_KEEP] = TCPTV_KEEP_INIT;
+	    tp->t_state = TCPS_SYN_RECEIVED;
+	    tcp_template(tp);
+	  }
+	  return;
+
+	cont_conn:
+	  /* m==NULL
+	   * Check if the connect succeeded
+	   */
+	  if (so->so_state & SS_NOFDREF) {
+	    tp = tcp_close(tp);
+	    goto dropwithreset;
+	  }
+	cont_input:
+	  tcp_template(tp);
+
+	  if (optp)
+	    tcp_dooptions(tp, (u_char *)optp, optlen, ti);
+
+	  if (iss)
+	    tp->iss = iss;
+	  else
+	    tp->iss = slirp->tcp_iss;
+	  slirp->tcp_iss += TCP_ISSINCR/2;
+	  tp->irs = ti->ti_seq;
+	  tcp_sendseqinit(tp);
+	  tcp_rcvseqinit(tp);
+	  tp->t_flags |= TF_ACKNOW;
+	  tp->t_state = TCPS_SYN_RECEIVED;
+	  tp->t_timer[TCPT_KEEP] = TCPTV_KEEP_INIT;
+	  goto trimthenstep6;
+	} /* case TCPS_LISTEN */
+
+	/*
+	 * If the state is SYN_SENT:
+	 *	if seg contains an ACK, but not for our SYN, drop the input.
+	 *	if seg contains a RST, then drop the connection.
+	 *	if seg does not contain SYN, then drop it.
+	 * Otherwise this is an acceptable SYN segment
+	 *	initialize tp->rcv_nxt and tp->irs
+	 *	if seg contains ack then advance tp->snd_una
+	 *	if SYN has been acked change to ESTABLISHED else SYN_RCVD state
+	 *	arrange for segment to be acked (eventually)
+	 *	continue processing rest of data/controls, beginning with URG
+	 */
+	case TCPS_SYN_SENT:
+		if ((tiflags & TH_ACK) &&
+		    (SEQ_LEQ(ti->ti_ack, tp->iss) ||
+		     SEQ_GT(ti->ti_ack, tp->snd_max)))
+			goto dropwithreset;
+
+		if (tiflags & TH_RST) {
+                        if (tiflags & TH_ACK) {
+                                tcp_drop(tp, 0); /* XXX Check t_softerror! */
+                        }
+			goto drop;
+		}
+
+		if ((tiflags & TH_SYN) == 0)
+			goto drop;
+		if (tiflags & TH_ACK) {
+			tp->snd_una = ti->ti_ack;
+			if (SEQ_LT(tp->snd_nxt, tp->snd_una))
+				tp->snd_nxt = tp->snd_una;
+		}
+
+		tp->t_timer[TCPT_REXMT] = 0;
+		tp->irs = ti->ti_seq;
+		tcp_rcvseqinit(tp);
+		tp->t_flags |= TF_ACKNOW;
+		if (tiflags & TH_ACK && SEQ_GT(tp->snd_una, tp->iss)) {
+			soisfconnected(so);
+			tp->t_state = TCPS_ESTABLISHED;
+
+			(void) tcp_reass(tp, (struct tcpiphdr *)0,
+				(struct mbuf *)0);
+			/*
+			 * if we didn't have to retransmit the SYN,
+			 * use its rtt as our initial srtt & rtt var.
+			 */
+			if (tp->t_rtt)
+				tcp_xmit_timer(tp, tp->t_rtt);
+		} else
+			tp->t_state = TCPS_SYN_RECEIVED;
+
+trimthenstep6:
+		/*
+		 * Advance ti->ti_seq to correspond to first data byte.
+		 * If data, trim to stay within window,
+		 * dropping FIN if necessary.
+		 */
+		ti->ti_seq++;
+		if (ti->ti_len > tp->rcv_wnd) {
+			todrop = ti->ti_len - tp->rcv_wnd;
+			m_adj(m, -todrop);
+			ti->ti_len = tp->rcv_wnd;
+			tiflags &= ~TH_FIN;
+		}
+		tp->snd_wl1 = ti->ti_seq - 1;
+		tp->rcv_up = ti->ti_seq;
+		goto step6;
+	} /* switch tp->t_state */
+	/*
+	 * States other than LISTEN or SYN_SENT.
+	 * Check that at least some bytes of segment are within
+	 * receive window.  If segment begins before rcv_nxt,
+	 * drop leading data (and SYN); if nothing left, just ack.
+	 */
+	todrop = tp->rcv_nxt - ti->ti_seq;
+	if (todrop > 0) {
+		if (tiflags & TH_SYN) {
+			tiflags &= ~TH_SYN;
+			ti->ti_seq++;
+			if (ti->ti_urp > 1)
+				ti->ti_urp--;
+			else
+				tiflags &= ~TH_URG;
+			todrop--;
+		}
+		/*
+		 * Following if statement from Stevens, vol. 2, p. 960.
+		 */
+		if (todrop > ti->ti_len
+		    || (todrop == ti->ti_len && (tiflags & TH_FIN) == 0)) {
+			/*
+			 * Any valid FIN must be to the left of the window.
+			 * At this point the FIN must be a duplicate or out
+			 * of sequence; drop it.
+			 */
+			tiflags &= ~TH_FIN;
+
+			/*
+			 * Send an ACK to resynchronize and drop any data.
+			 * But keep on processing for RST or ACK.
+			 */
+			tp->t_flags |= TF_ACKNOW;
+			todrop = ti->ti_len;
+		}
+		m_adj(m, todrop);
+		ti->ti_seq += todrop;
+		ti->ti_len -= todrop;
+		if (ti->ti_urp > todrop)
+			ti->ti_urp -= todrop;
+		else {
+			tiflags &= ~TH_URG;
+			ti->ti_urp = 0;
+		}
+	}
+	/*
+	 * If new data are received on a connection after the
+	 * user processes are gone, then RST the other end.
+	 */
+	if ((so->so_state & SS_NOFDREF) &&
+	    tp->t_state > TCPS_CLOSE_WAIT && ti->ti_len) {
+		tp = tcp_close(tp);
+		goto dropwithreset;
+	}
+
+	/*
+	 * If segment ends after window, drop trailing data
+	 * (and PUSH and FIN); if nothing left, just ACK.
+	 */
+	todrop = (ti->ti_seq+ti->ti_len) - (tp->rcv_nxt+tp->rcv_wnd);
+	if (todrop > 0) {
+		if (todrop >= ti->ti_len) {
+			/*
+			 * If a new connection request is received
+			 * while in TIME_WAIT, drop the old connection
+			 * and start over if the sequence numbers
+			 * are above the previous ones.
+			 */
+			if (tiflags & TH_SYN &&
+			    tp->t_state == TCPS_TIME_WAIT &&
+			    SEQ_GT(ti->ti_seq, tp->rcv_nxt)) {
+				iss = tp->rcv_nxt + TCP_ISSINCR;
+				tp = tcp_close(tp);
+				goto findso;
+			}
+			/*
+			 * If window is closed can only take segments at
+			 * window edge, and have to drop data and PUSH from
+			 * incoming segments.  Continue processing, but
+			 * remember to ack.  Otherwise, drop segment
+			 * and ack.
+			 */
+			if (tp->rcv_wnd == 0 && ti->ti_seq == tp->rcv_nxt) {
+				tp->t_flags |= TF_ACKNOW;
+			} else {
+				goto dropafterack;
+			}
+		}
+		m_adj(m, -todrop);
+		ti->ti_len -= todrop;
+		tiflags &= ~(TH_PUSH|TH_FIN);
+	}
+
+	/*
+	 * If the RST bit is set examine the state:
+	 *    SYN_RECEIVED STATE:
+	 *	If passive open, return to LISTEN state.
+	 *	If active open, inform user that connection was refused.
+	 *    ESTABLISHED, FIN_WAIT_1, FIN_WAIT2, CLOSE_WAIT STATES:
+	 *	Inform user that connection was reset, and close tcb.
+	 *    CLOSING, LAST_ACK, TIME_WAIT STATES
+	 *	Close the tcb.
+	 */
+	if (tiflags&TH_RST) switch (tp->t_state) {
+
+	case TCPS_SYN_RECEIVED:
+	case TCPS_ESTABLISHED:
+	case TCPS_FIN_WAIT_1:
+	case TCPS_FIN_WAIT_2:
+	case TCPS_CLOSE_WAIT:
+		tp->t_state = TCPS_CLOSED;
+                tcp_close(tp);
+		goto drop;
+
+	case TCPS_CLOSING:
+	case TCPS_LAST_ACK:
+	case TCPS_TIME_WAIT:
+                tcp_close(tp);
+		goto drop;
+	}
+
+	/*
+	 * If a SYN is in the window, then this is an
+	 * error and we send an RST and drop the connection.
+	 */
+	if (tiflags & TH_SYN) {
+		tp = tcp_drop(tp,0);
+		goto dropwithreset;
+	}
+
+	/*
+	 * If the ACK bit is off we drop the segment and return.
+	 */
+	if ((tiflags & TH_ACK) == 0) goto drop;
+
+	/*
+	 * Ack processing.
+	 */
+	switch (tp->t_state) {
+	/*
+	 * In SYN_RECEIVED state if the ack ACKs our SYN then enter
+	 * ESTABLISHED state and continue processing, otherwise
+	 * send an RST.  una<=ack<=max
+	 */
+	case TCPS_SYN_RECEIVED:
+
+		if (SEQ_GT(tp->snd_una, ti->ti_ack) ||
+		    SEQ_GT(ti->ti_ack, tp->snd_max))
+			goto dropwithreset;
+		tp->t_state = TCPS_ESTABLISHED;
+		/*
+		 * The sent SYN is ack'ed with our sequence number +1
+		 * The first data byte already in the buffer will get
+		 * lost if no correction is made.  This is only needed for
+		 * SS_CTL since the buffer is empty otherwise.
+		 * tp->snd_una++; or:
+		 */
+		tp->snd_una=ti->ti_ack;
+		if (so->so_state & SS_CTL) {
+		  /* So tcp_ctl reports the right state */
+		  ret = tcp_ctl(so);
+		  if (ret == 1) {
+		    soisfconnected(so);
+		    so->so_state &= ~SS_CTL;   /* success XXX */
+		  } else if (ret == 2) {
+		    so->so_state &= SS_PERSISTENT_MASK;
+		    so->so_state |= SS_NOFDREF; /* CTL_CMD */
+		  } else {
+		    needoutput = 1;
+		    tp->t_state = TCPS_FIN_WAIT_1;
+		  }
+		} else {
+		  soisfconnected(so);
+		}
+
+		(void) tcp_reass(tp, (struct tcpiphdr *)0, (struct mbuf *)0);
+		tp->snd_wl1 = ti->ti_seq - 1;
+		/* Avoid ack processing; snd_una==ti_ack  =>  dup ack */
+		goto synrx_to_est;
+		/* fall into ... */
+
+	/*
+	 * In ESTABLISHED state: drop duplicate ACKs; ACK out of range
+	 * ACKs.  If the ack is in the range
+	 *	tp->snd_una < ti->ti_ack <= tp->snd_max
+	 * then advance tp->snd_una to ti->ti_ack and drop
+	 * data from the retransmission queue.  If this ACK reflects
+	 * more up to date window information we update our window information.
+	 */
+	case TCPS_ESTABLISHED:
+	case TCPS_FIN_WAIT_1:
+	case TCPS_FIN_WAIT_2:
+	case TCPS_CLOSE_WAIT:
+	case TCPS_CLOSING:
+	case TCPS_LAST_ACK:
+	case TCPS_TIME_WAIT:
+
+		if (SEQ_LEQ(ti->ti_ack, tp->snd_una)) {
+			if (ti->ti_len == 0 && tiwin == tp->snd_wnd) {
+			  DEBUG_MISC((dfd, " dup ack  m = %p  so = %p\n",
+				      m, so));
+				/*
+				 * If we have outstanding data (other than
+				 * a window probe), this is a completely
+				 * duplicate ack (ie, window info didn't
+				 * change), the ack is the biggest we've
+				 * seen and we've seen exactly our rexmt
+				 * threshold of them, assume a packet
+				 * has been dropped and retransmit it.
+				 * Kludge snd_nxt & the congestion
+				 * window so we send only this one
+				 * packet.
+				 *
+				 * We know we're losing at the current
+				 * window size so do congestion avoidance
+				 * (set ssthresh to half the current window
+				 * and pull our congestion window back to
+				 * the new ssthresh).
+				 *
+				 * Dup acks mean that packets have left the
+				 * network (they're now cached at the receiver)
+				 * so bump cwnd by the amount in the receiver
+				 * to keep a constant cwnd packets in the
+				 * network.
+				 */
+				if (tp->t_timer[TCPT_REXMT] == 0 ||
+				    ti->ti_ack != tp->snd_una)
+					tp->t_dupacks = 0;
+				else if (++tp->t_dupacks == TCPREXMTTHRESH) {
+					tcp_seq onxt = tp->snd_nxt;
+					u_int win =
+					    min(tp->snd_wnd, tp->snd_cwnd) / 2 /
+						tp->t_maxseg;
+
+					if (win < 2)
+						win = 2;
+					tp->snd_ssthresh = win * tp->t_maxseg;
+					tp->t_timer[TCPT_REXMT] = 0;
+					tp->t_rtt = 0;
+					tp->snd_nxt = ti->ti_ack;
+					tp->snd_cwnd = tp->t_maxseg;
+					(void) tcp_output(tp);
+					tp->snd_cwnd = tp->snd_ssthresh +
+					       tp->t_maxseg * tp->t_dupacks;
+					if (SEQ_GT(onxt, tp->snd_nxt))
+						tp->snd_nxt = onxt;
+					goto drop;
+				} else if (tp->t_dupacks > TCPREXMTTHRESH) {
+					tp->snd_cwnd += tp->t_maxseg;
+					(void) tcp_output(tp);
+					goto drop;
+				}
+			} else
+				tp->t_dupacks = 0;
+			break;
+		}
+	synrx_to_est:
+		/*
+		 * If the congestion window was inflated to account
+		 * for the other side's cached packets, retract it.
+		 */
+		if (tp->t_dupacks > TCPREXMTTHRESH &&
+		    tp->snd_cwnd > tp->snd_ssthresh)
+			tp->snd_cwnd = tp->snd_ssthresh;
+		tp->t_dupacks = 0;
+		if (SEQ_GT(ti->ti_ack, tp->snd_max)) {
+			goto dropafterack;
+		}
+		acked = ti->ti_ack - tp->snd_una;
+
+		/*
+		 * If transmit timer is running and timed sequence
+		 * number was acked, update smoothed round trip time.
+		 * Since we now have an rtt measurement, cancel the
+		 * timer backoff (cf., Phil Karn's retransmit alg.).
+		 * Recompute the initial retransmit timer.
+		 */
+		if (tp->t_rtt && SEQ_GT(ti->ti_ack, tp->t_rtseq))
+			tcp_xmit_timer(tp,tp->t_rtt);
+
+		/*
+		 * If all outstanding data is acked, stop retransmit
+		 * timer and remember to restart (more output or persist).
+		 * If there is more data to be acked, restart retransmit
+		 * timer, using current (possibly backed-off) value.
+		 */
+		if (ti->ti_ack == tp->snd_max) {
+			tp->t_timer[TCPT_REXMT] = 0;
+			needoutput = 1;
+		} else if (tp->t_timer[TCPT_PERSIST] == 0)
+			tp->t_timer[TCPT_REXMT] = tp->t_rxtcur;
+		/*
+		 * When new data is acked, open the congestion window.
+		 * If the window gives us less than ssthresh packets
+		 * in flight, open exponentially (maxseg per packet).
+		 * Otherwise open linearly: maxseg per window
+		 * (maxseg^2 / cwnd per packet).
+		 */
+		{
+		  register u_int cw = tp->snd_cwnd;
+		  register u_int incr = tp->t_maxseg;
+
+		  if (cw > tp->snd_ssthresh)
+		    incr = incr * incr / cw;
+		  tp->snd_cwnd = min(cw + incr, TCP_MAXWIN<<tp->snd_scale);
+		}
+		if (acked > so->so_snd.sb_cc) {
+			tp->snd_wnd -= so->so_snd.sb_cc;
+			sbdrop(&so->so_snd, (int )so->so_snd.sb_cc);
+			ourfinisacked = 1;
+		} else {
+			sbdrop(&so->so_snd, acked);
+			tp->snd_wnd -= acked;
+			ourfinisacked = 0;
+		}
+		tp->snd_una = ti->ti_ack;
+		if (SEQ_LT(tp->snd_nxt, tp->snd_una))
+			tp->snd_nxt = tp->snd_una;
+
+		switch (tp->t_state) {
+
+		/*
+		 * In FIN_WAIT_1 STATE in addition to the processing
+		 * for the ESTABLISHED state if our FIN is now acknowledged
+		 * then enter FIN_WAIT_2.
+		 */
+		case TCPS_FIN_WAIT_1:
+			if (ourfinisacked) {
+				/*
+				 * If we can't receive any more
+				 * data, then closing user can proceed.
+				 * Starting the timer is contrary to the
+				 * specification, but if we don't get a FIN
+				 * we'll hang forever.
+				 */
+				if (so->so_state & SS_FCANTRCVMORE) {
+					tp->t_timer[TCPT_2MSL] = TCP_MAXIDLE;
+				}
+				tp->t_state = TCPS_FIN_WAIT_2;
+			}
+			break;
+
+	 	/*
+		 * In CLOSING STATE in addition to the processing for
+		 * the ESTABLISHED state if the ACK acknowledges our FIN
+		 * then enter the TIME-WAIT state, otherwise ignore
+		 * the segment.
+		 */
+		case TCPS_CLOSING:
+			if (ourfinisacked) {
+				tp->t_state = TCPS_TIME_WAIT;
+				tcp_canceltimers(tp);
+				tp->t_timer[TCPT_2MSL] = 2 * TCPTV_MSL;
+			}
+			break;
+
+		/*
+		 * In LAST_ACK, we may still be waiting for data to drain
+		 * and/or to be acked, as well as for the ack of our FIN.
+		 * If our FIN is now acknowledged, delete the TCB,
+		 * enter the closed state and return.
+		 */
+		case TCPS_LAST_ACK:
+			if (ourfinisacked) {
+                                tcp_close(tp);
+				goto drop;
+			}
+			break;
+
+		/*
+		 * In TIME_WAIT state the only thing that should arrive
+		 * is a retransmission of the remote FIN.  Acknowledge
+		 * it and restart the finack timer.
+		 */
+		case TCPS_TIME_WAIT:
+			tp->t_timer[TCPT_2MSL] = 2 * TCPTV_MSL;
+			goto dropafterack;
+		}
+	} /* switch(tp->t_state) */
+
+step6:
+	/*
+	 * Update window information.
+	 * Don't look at window if no ACK: TAC's send garbage on first SYN.
+	 */
+	if ((tiflags & TH_ACK) &&
+	    (SEQ_LT(tp->snd_wl1, ti->ti_seq) ||
+	    (tp->snd_wl1 == ti->ti_seq && (SEQ_LT(tp->snd_wl2, ti->ti_ack) ||
+	    (tp->snd_wl2 == ti->ti_ack && tiwin > tp->snd_wnd))))) {
+		tp->snd_wnd = tiwin;
+		tp->snd_wl1 = ti->ti_seq;
+		tp->snd_wl2 = ti->ti_ack;
+		if (tp->snd_wnd > tp->max_sndwnd)
+			tp->max_sndwnd = tp->snd_wnd;
+		needoutput = 1;
+	}
+
+	/*
+	 * Process segments with URG.
+	 */
+	if ((tiflags & TH_URG) && ti->ti_urp &&
+	    TCPS_HAVERCVDFIN(tp->t_state) == 0) {
+		/*
+		 * This is a kludge, but if we receive and accept
+		 * random urgent pointers, we'll crash in
+		 * soreceive.  It's hard to imagine someone
+		 * actually wanting to send this much urgent data.
+		 */
+		if (ti->ti_urp + so->so_rcv.sb_cc > so->so_rcv.sb_datalen) {
+			ti->ti_urp = 0;
+			tiflags &= ~TH_URG;
+			goto dodata;
+		}
+		/*
+		 * If this segment advances the known urgent pointer,
+		 * then mark the data stream.  This should not happen
+		 * in CLOSE_WAIT, CLOSING, LAST_ACK or TIME_WAIT STATES since
+		 * a FIN has been received from the remote side.
+		 * In these states we ignore the URG.
+		 *
+		 * According to RFC961 (Assigned Protocols),
+		 * the urgent pointer points to the last octet
+		 * of urgent data.  We continue, however,
+		 * to consider it to indicate the first octet
+		 * of data past the urgent section as the original
+		 * spec states (in one of two places).
+		 */
+		if (SEQ_GT(ti->ti_seq+ti->ti_urp, tp->rcv_up)) {
+			tp->rcv_up = ti->ti_seq + ti->ti_urp;
+			so->so_urgc =  so->so_rcv.sb_cc +
+				(tp->rcv_up - tp->rcv_nxt); /* -1; */
+			tp->rcv_up = ti->ti_seq + ti->ti_urp;
+
+		}
+	} else
+		/*
+		 * If no out of band data is expected,
+		 * pull receive urgent pointer along
+		 * with the receive window.
+		 */
+		if (SEQ_GT(tp->rcv_nxt, tp->rcv_up))
+			tp->rcv_up = tp->rcv_nxt;
+dodata:
+
+	/*
+	 * If this is a small packet, then ACK now - with Nagel
+	 *      congestion avoidance sender won't send more until
+	 *      he gets an ACK.
+	 */
+	if (ti->ti_len && (unsigned)ti->ti_len <= 5 &&
+	    ((struct tcpiphdr_2 *)ti)->first_char == (char)27) {
+		tp->t_flags |= TF_ACKNOW;
+	}
+
+	/*
+	 * Process the segment text, merging it into the TCP sequencing queue,
+	 * and arranging for acknowledgment of receipt if necessary.
+	 * This process logically involves adjusting tp->rcv_wnd as data
+	 * is presented to the user (this happens in tcp_usrreq.c,
+	 * case PRU_RCVD).  If a FIN has already been received on this
+	 * connection then we just ignore the text.
+	 */
+	if ((ti->ti_len || (tiflags&TH_FIN)) &&
+	    TCPS_HAVERCVDFIN(tp->t_state) == 0) {
+		TCP_REASS(tp, ti, m, so, tiflags);
+	} else {
+		m_free(m);
+		tiflags &= ~TH_FIN;
+	}
+
+	/*
+	 * If FIN is received ACK the FIN and let the user know
+	 * that the connection is closing.
+	 */
+	if (tiflags & TH_FIN) {
+		if (TCPS_HAVERCVDFIN(tp->t_state) == 0) {
+			/*
+			 * If we receive a FIN we can't send more data,
+			 * set it SS_FDRAIN
+                         * Shutdown the socket if there is no rx data in the
+			 * buffer.
+			 * soread() is called on completion of shutdown() and
+			 * will got to TCPS_LAST_ACK, and use tcp_output()
+			 * to send the FIN.
+			 */
+			sofwdrain(so);
+
+			tp->t_flags |= TF_ACKNOW;
+			tp->rcv_nxt++;
+		}
+		switch (tp->t_state) {
+
+	 	/*
+		 * In SYN_RECEIVED and ESTABLISHED STATES
+		 * enter the CLOSE_WAIT state.
+		 */
+		case TCPS_SYN_RECEIVED:
+		case TCPS_ESTABLISHED:
+		  if(so->so_emu == EMU_CTL)        /* no shutdown on socket */
+		    tp->t_state = TCPS_LAST_ACK;
+		  else
+		    tp->t_state = TCPS_CLOSE_WAIT;
+		  break;
+
+	 	/*
+		 * If still in FIN_WAIT_1 STATE FIN has not been acked so
+		 * enter the CLOSING state.
+		 */
+		case TCPS_FIN_WAIT_1:
+			tp->t_state = TCPS_CLOSING;
+			break;
+
+	 	/*
+		 * In FIN_WAIT_2 state enter the TIME_WAIT state,
+		 * starting the time-wait timer, turning off the other
+		 * standard timers.
+		 */
+		case TCPS_FIN_WAIT_2:
+			tp->t_state = TCPS_TIME_WAIT;
+			tcp_canceltimers(tp);
+			tp->t_timer[TCPT_2MSL] = 2 * TCPTV_MSL;
+			break;
+
+		/*
+		 * In TIME_WAIT state restart the 2 MSL time_wait timer.
+		 */
+		case TCPS_TIME_WAIT:
+			tp->t_timer[TCPT_2MSL] = 2 * TCPTV_MSL;
+			break;
+		}
+	}
+
+	/*
+	 * Return any desired output.
+	 */
+	if (needoutput || (tp->t_flags & TF_ACKNOW)) {
+		(void) tcp_output(tp);
+	}
+	return;
+
+dropafterack:
+	/*
+	 * Generate an ACK dropping incoming segment if it occupies
+	 * sequence space, where the ACK reflects our state.
+	 */
+	if (tiflags & TH_RST)
+		goto drop;
+	m_free(m);
+	tp->t_flags |= TF_ACKNOW;
+	(void) tcp_output(tp);
+	return;
+
+dropwithreset:
+	/* reuses m if m!=NULL, m_free() unnecessary */
+	if (tiflags & TH_ACK)
+		tcp_respond(tp, ti, m, (tcp_seq)0, ti->ti_ack, TH_RST);
+	else {
+		if (tiflags & TH_SYN) ti->ti_len++;
+		tcp_respond(tp, ti, m, ti->ti_seq+ti->ti_len, (tcp_seq)0,
+		    TH_RST|TH_ACK);
+	}
+
+	return;
+
+drop:
+	/*
+	 * Drop space held by incoming segment and return.
+	 */
+	m_free(m);
+}
+
+static void
+tcp_dooptions(struct tcpcb *tp, u_char *cp, int cnt, struct tcpiphdr *ti)
+{
+	uint16_t mss;
+	int opt, optlen;
+
+	DEBUG_CALL("tcp_dooptions");
+	DEBUG_ARGS((dfd, " tp = %p  cnt=%i\n", tp, cnt));
+
+	for (; cnt > 0; cnt -= optlen, cp += optlen) {
+		opt = cp[0];
+		if (opt == TCPOPT_EOL)
+			break;
+		if (opt == TCPOPT_NOP)
+			optlen = 1;
+		else {
+			optlen = cp[1];
+			if (optlen <= 0)
+				break;
+		}
+		switch (opt) {
+
+		default:
+			continue;
+
+		case TCPOPT_MAXSEG:
+			if (optlen != TCPOLEN_MAXSEG)
+				continue;
+			if (!(ti->ti_flags & TH_SYN))
+				continue;
+			memcpy((char *) &mss, (char *) cp + 2, sizeof(mss));
+			NTOHS(mss);
+			(void) tcp_mss(tp, mss);	/* sets t_maxseg */
+			break;
+		}
+	}
+}
+
+
+/*
+ * Pull out of band byte out of a segment so
+ * it doesn't appear in the user's data queue.
+ * It is still reflected in the segment length for
+ * sequencing purposes.
+ */
+
+#ifdef notdef
+
+void
+tcp_pulloutofband(so, ti, m)
+	struct socket *so;
+	struct tcpiphdr *ti;
+	register struct mbuf *m;
+{
+	int cnt = ti->ti_urp - 1;
+
+	while (cnt >= 0) {
+		if (m->m_len > cnt) {
+			char *cp = mtod(m, caddr_t) + cnt;
+			struct tcpcb *tp = sototcpcb(so);
+
+			tp->t_iobc = *cp;
+			tp->t_oobflags |= TCPOOB_HAVEDATA;
+			memcpy(sp, cp+1, (unsigned)(m->m_len - cnt - 1));
+			m->m_len--;
+			return;
+		}
+		cnt -= m->m_len;
+		m = m->m_next; /* XXX WRONG! Fix it! */
+		if (m == 0)
+			break;
+	}
+	panic("tcp_pulloutofband");
+}
+
+#endif /* notdef */
+
+/*
+ * Collect new round-trip time estimate
+ * and update averages and current timeout.
+ */
+
+static void
+tcp_xmit_timer(register struct tcpcb *tp, int rtt)
+{
+	register short delta;
+
+	DEBUG_CALL("tcp_xmit_timer");
+	DEBUG_ARG("tp = %p", tp);
+	DEBUG_ARG("rtt = %d", rtt);
+
+	if (tp->t_srtt != 0) {
+		/*
+		 * srtt is stored as fixed point with 3 bits after the
+		 * binary point (i.e., scaled by 8).  The following magic
+		 * is equivalent to the smoothing algorithm in rfc793 with
+		 * an alpha of .875 (srtt = rtt/8 + srtt*7/8 in fixed
+		 * point).  Adjust rtt to origin 0.
+		 */
+		delta = rtt - 1 - (tp->t_srtt >> TCP_RTT_SHIFT);
+		if ((tp->t_srtt += delta) <= 0)
+			tp->t_srtt = 1;
+		/*
+		 * We accumulate a smoothed rtt variance (actually, a
+		 * smoothed mean difference), then set the retransmit
+		 * timer to smoothed rtt + 4 times the smoothed variance.
+		 * rttvar is stored as fixed point with 2 bits after the
+		 * binary point (scaled by 4).  The following is
+		 * equivalent to rfc793 smoothing with an alpha of .75
+		 * (rttvar = rttvar*3/4 + |delta| / 4).  This replaces
+		 * rfc793's wired-in beta.
+		 */
+		if (delta < 0)
+			delta = -delta;
+		delta -= (tp->t_rttvar >> TCP_RTTVAR_SHIFT);
+		if ((tp->t_rttvar += delta) <= 0)
+			tp->t_rttvar = 1;
+	} else {
+		/*
+		 * No rtt measurement yet - use the unsmoothed rtt.
+		 * Set the variance to half the rtt (so our first
+		 * retransmit happens at 3*rtt).
+		 */
+		tp->t_srtt = rtt << TCP_RTT_SHIFT;
+		tp->t_rttvar = rtt << (TCP_RTTVAR_SHIFT - 1);
+	}
+	tp->t_rtt = 0;
+	tp->t_rxtshift = 0;
+
+	/*
+	 * the retransmit should happen at rtt + 4 * rttvar.
+	 * Because of the way we do the smoothing, srtt and rttvar
+	 * will each average +1/2 tick of bias.  When we compute
+	 * the retransmit timer, we want 1/2 tick of rounding and
+	 * 1 extra tick because of +-1/2 tick uncertainty in the
+	 * firing of the timer.  The bias will give us exactly the
+	 * 1.5 tick we need.  But, because the bias is
+	 * statistical, we have to test that we don't drop below
+	 * the minimum feasible timer (which is 2 ticks).
+	 */
+	TCPT_RANGESET(tp->t_rxtcur, TCP_REXMTVAL(tp),
+	    (short)tp->t_rttmin, TCPTV_REXMTMAX); /* XXX */
+
+	/*
+	 * We received an ack for a packet that wasn't retransmitted;
+	 * it is probably safe to discard any error indications we've
+	 * received recently.  This isn't quite right, but close enough
+	 * for now (a route might have failed after we sent a segment,
+	 * and the return path might not be symmetrical).
+	 */
+	tp->t_softerror = 0;
+}
+
+/*
+ * Determine a reasonable value for maxseg size.
+ * If the route is known, check route for mtu.
+ * If none, use an mss that can be handled on the outgoing
+ * interface without forcing IP to fragment; if bigger than
+ * an mbuf cluster (MCLBYTES), round down to nearest multiple of MCLBYTES
+ * to utilize large mbufs.  If no route is found, route has no mtu,
+ * or the destination isn't local, use a default, hopefully conservative
+ * size (usually 512 or the default IP max size, but no more than the mtu
+ * of the interface), as we can't discover anything about intervening
+ * gateways or networks.  We also initialize the congestion/slow start
+ * window to be a single segment if the destination isn't local.
+ * While looking at the routing entry, we also initialize other path-dependent
+ * parameters from pre-set or cached values in the routing entry.
+ */
+
+int
+tcp_mss(struct tcpcb *tp, u_int offer)
+{
+	struct socket *so = tp->t_socket;
+	int mss;
+
+	DEBUG_CALL("tcp_mss");
+	DEBUG_ARG("tp = %p", tp);
+	DEBUG_ARG("offer = %d", offer);
+
+	mss = min(IF_MTU, IF_MRU) - sizeof(struct tcpiphdr);
+	if (offer)
+		mss = min(mss, offer);
+	mss = max(mss, 32);
+	if (mss < tp->t_maxseg || offer != 0)
+	   tp->t_maxseg = mss;
+
+	tp->snd_cwnd = mss;
+
+	sbreserve(&so->so_snd, TCP_SNDSPACE + ((TCP_SNDSPACE % mss) ?
+                                               (mss - (TCP_SNDSPACE % mss)) :
+                                               0));
+	sbreserve(&so->so_rcv, TCP_RCVSPACE + ((TCP_RCVSPACE % mss) ?
+                                               (mss - (TCP_RCVSPACE % mss)) :
+                                               0));
+
+	DEBUG_MISC((dfd, " returning mss = %d\n", mss));
+
+	return mss;
+}
diff --git a/src/slirp/tcp_output.c b/src/slirp/tcp_output.c
new file mode 100644
index 0000000..fafca58
--- /dev/null
+++ b/src/slirp/tcp_output.c
@@ -0,0 +1,493 @@
+/*
+ * Copyright (c) 1982, 1986, 1988, 1990, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)tcp_output.c	8.3 (Berkeley) 12/30/93
+ * tcp_output.c,v 1.3 1994/09/15 10:36:55 davidg Exp
+ */
+
+/*
+ * Changes and additions relating to SLiRP
+ * Copyright (c) 1995 Danny Gasparovski.
+ *
+ * Please read the file COPYRIGHT for the
+ * terms and conditions of the copyright.
+ */
+
+#include <slirp.h>
+
+static const u_char  tcp_outflags[TCP_NSTATES] = {
+	TH_RST|TH_ACK, 0,      TH_SYN,        TH_SYN|TH_ACK,
+	TH_ACK,        TH_ACK, TH_FIN|TH_ACK, TH_FIN|TH_ACK,
+	TH_FIN|TH_ACK, TH_ACK, TH_ACK,
+};
+
+
+#undef MAX_TCPOPTLEN
+#define MAX_TCPOPTLEN	32	/* max # bytes that go in options */
+
+/*
+ * Tcp output routine: figure out what should be sent and send it.
+ */
+int
+tcp_output(struct tcpcb *tp)
+{
+	register struct socket *so = tp->t_socket;
+	register long len, win;
+	int off, flags, error;
+	register struct mbuf *m;
+	register struct tcpiphdr *ti;
+	u_char opt[MAX_TCPOPTLEN];
+	unsigned optlen, hdrlen;
+	int idle, sendalot;
+
+	DEBUG_CALL("tcp_output");
+	DEBUG_ARG("tp = %p", tp);
+
+	/*
+	 * Determine length of data that should be transmitted,
+	 * and flags that will be used.
+	 * If there is some data or critical controls (SYN, RST)
+	 * to send, then transmit; otherwise, investigate further.
+	 */
+	idle = (tp->snd_max == tp->snd_una);
+	if (idle && tp->t_idle >= tp->t_rxtcur)
+		/*
+		 * We have been idle for "a while" and no acks are
+		 * expected to clock out any data we send --
+		 * slow start to get ack "clock" running again.
+		 */
+		tp->snd_cwnd = tp->t_maxseg;
+again:
+	sendalot = 0;
+	off = tp->snd_nxt - tp->snd_una;
+	win = min(tp->snd_wnd, tp->snd_cwnd);
+
+	flags = tcp_outflags[tp->t_state];
+
+	DEBUG_MISC((dfd, " --- tcp_output flags = 0x%x\n",flags));
+
+	/*
+	 * If in persist timeout with window of 0, send 1 byte.
+	 * Otherwise, if window is small but nonzero
+	 * and timer expired, we will send what we can
+	 * and go to transmit state.
+	 */
+	if (tp->t_force) {
+		if (win == 0) {
+			/*
+			 * If we still have some data to send, then
+			 * clear the FIN bit.  Usually this would
+			 * happen below when it realizes that we
+			 * aren't sending all the data.  However,
+			 * if we have exactly 1 byte of unset data,
+			 * then it won't clear the FIN bit below,
+			 * and if we are in persist state, we wind
+			 * up sending the packet without recording
+			 * that we sent the FIN bit.
+			 *
+			 * We can't just blindly clear the FIN bit,
+			 * because if we don't have any more data
+			 * to send then the probe will be the FIN
+			 * itself.
+			 */
+			if (off < so->so_snd.sb_cc)
+				flags &= ~TH_FIN;
+			win = 1;
+		} else {
+			tp->t_timer[TCPT_PERSIST] = 0;
+			tp->t_rxtshift = 0;
+		}
+	}
+
+	len = min(so->so_snd.sb_cc, win) - off;
+
+	if (len < 0) {
+		/*
+		 * If FIN has been sent but not acked,
+		 * but we haven't been called to retransmit,
+		 * len will be -1.  Otherwise, window shrank
+		 * after we sent into it.  If window shrank to 0,
+		 * cancel pending retransmit and pull snd_nxt
+		 * back to (closed) window.  We will enter persist
+		 * state below.  If the window didn't close completely,
+		 * just wait for an ACK.
+		 */
+		len = 0;
+		if (win == 0) {
+			tp->t_timer[TCPT_REXMT] = 0;
+			tp->snd_nxt = tp->snd_una;
+		}
+	}
+
+	if (len > tp->t_maxseg) {
+		len = tp->t_maxseg;
+		sendalot = 1;
+	}
+	if (SEQ_LT(tp->snd_nxt + len, tp->snd_una + so->so_snd.sb_cc))
+		flags &= ~TH_FIN;
+
+	win = sbspace(&so->so_rcv);
+
+	/*
+	 * Sender silly window avoidance.  If connection is idle
+	 * and can send all data, a maximum segment,
+	 * at least a maximum default-size segment do it,
+	 * or are forced, do it; otherwise don't bother.
+	 * If peer's buffer is tiny, then send
+	 * when window is at least half open.
+	 * If retransmitting (possibly after persist timer forced us
+	 * to send into a small window), then must resend.
+	 */
+	if (len) {
+		if (len == tp->t_maxseg)
+			goto send;
+		if ((1 || idle || tp->t_flags & TF_NODELAY) &&
+		    len + off >= so->so_snd.sb_cc)
+			goto send;
+		if (tp->t_force)
+			goto send;
+		if (len >= tp->max_sndwnd / 2 && tp->max_sndwnd > 0)
+			goto send;
+		if (SEQ_LT(tp->snd_nxt, tp->snd_max))
+			goto send;
+	}
+
+	/*
+	 * Compare available window to amount of window
+	 * known to peer (as advertised window less
+	 * next expected input).  If the difference is at least two
+	 * max size segments, or at least 50% of the maximum possible
+	 * window, then want to send a window update to peer.
+	 */
+	if (win > 0) {
+		/*
+		 * "adv" is the amount we can increase the window,
+		 * taking into account that we are limited by
+		 * TCP_MAXWIN << tp->rcv_scale.
+		 */
+		long adv = min(win, (long)TCP_MAXWIN << tp->rcv_scale) -
+			(tp->rcv_adv - tp->rcv_nxt);
+
+		if (adv >= (long) (2 * tp->t_maxseg))
+			goto send;
+		if (2 * adv >= (long) so->so_rcv.sb_datalen)
+			goto send;
+	}
+
+	/*
+	 * Send if we owe peer an ACK.
+	 */
+	if (tp->t_flags & TF_ACKNOW)
+		goto send;
+	if (flags & (TH_SYN|TH_RST))
+		goto send;
+	if (SEQ_GT(tp->snd_up, tp->snd_una))
+		goto send;
+	/*
+	 * If our state indicates that FIN should be sent
+	 * and we have not yet done so, or we're retransmitting the FIN,
+	 * then we need to send.
+	 */
+	if (flags & TH_FIN &&
+	    ((tp->t_flags & TF_SENTFIN) == 0 || tp->snd_nxt == tp->snd_una))
+		goto send;
+
+	/*
+	 * TCP window updates are not reliable, rather a polling protocol
+	 * using ``persist'' packets is used to insure receipt of window
+	 * updates.  The three ``states'' for the output side are:
+	 *	idle			not doing retransmits or persists
+	 *	persisting		to move a small or zero window
+	 *	(re)transmitting	and thereby not persisting
+	 *
+	 * tp->t_timer[TCPT_PERSIST]
+	 *	is set when we are in persist state.
+	 * tp->t_force
+	 *	is set when we are called to send a persist packet.
+	 * tp->t_timer[TCPT_REXMT]
+	 *	is set when we are retransmitting
+	 * The output side is idle when both timers are zero.
+	 *
+	 * If send window is too small, there is data to transmit, and no
+	 * retransmit or persist is pending, then go to persist state.
+	 * If nothing happens soon, send when timer expires:
+	 * if window is nonzero, transmit what we can,
+	 * otherwise force out a byte.
+	 */
+	if (so->so_snd.sb_cc && tp->t_timer[TCPT_REXMT] == 0 &&
+	    tp->t_timer[TCPT_PERSIST] == 0) {
+		tp->t_rxtshift = 0;
+		tcp_setpersist(tp);
+	}
+
+	/*
+	 * No reason to send a segment, just return.
+	 */
+	return (0);
+
+send:
+	/*
+	 * Before ESTABLISHED, force sending of initial options
+	 * unless TCP set not to do any options.
+	 * NOTE: we assume that the IP/TCP header plus TCP options
+	 * always fit in a single mbuf, leaving room for a maximum
+	 * link header, i.e.
+	 *	max_linkhdr + sizeof (struct tcpiphdr) + optlen <= MHLEN
+	 */
+	optlen = 0;
+	hdrlen = sizeof (struct tcpiphdr);
+	if (flags & TH_SYN) {
+		tp->snd_nxt = tp->iss;
+		if ((tp->t_flags & TF_NOOPT) == 0) {
+			uint16_t mss;
+
+			opt[0] = TCPOPT_MAXSEG;
+			opt[1] = 4;
+			mss = htons((uint16_t) tcp_mss(tp, 0));
+			memcpy((caddr_t)(opt + 2), (caddr_t)&mss, sizeof(mss));
+			optlen = 4;
+		}
+ 	}
+
+ 	hdrlen += optlen;
+
+	/*
+	 * Adjust data length if insertion of options will
+	 * bump the packet length beyond the t_maxseg length.
+	 */
+	 if (len > tp->t_maxseg - optlen) {
+		len = tp->t_maxseg - optlen;
+		sendalot = 1;
+	 }
+
+	/*
+	 * Grab a header mbuf, attaching a copy of data to
+	 * be transmitted, and initialize the header from
+	 * the template for sends on this connection.
+	 */
+	if (len) {
+		m = m_get(so->slirp);
+		if (m == NULL) {
+			error = 1;
+			goto out;
+		}
+		m->m_data += IF_MAXLINKHDR;
+		m->m_len = hdrlen;
+
+		sbcopy(&so->so_snd, off, (int) len, mtod(m, caddr_t) + hdrlen);
+		m->m_len += len;
+
+		/*
+		 * If we're sending everything we've got, set PUSH.
+		 * (This will keep happy those implementations which only
+		 * give data to the user when a buffer fills or
+		 * a PUSH comes in.)
+		 */
+		if (off + len == so->so_snd.sb_cc)
+			flags |= TH_PUSH;
+	} else {
+		m = m_get(so->slirp);
+		if (m == NULL) {
+			error = 1;
+			goto out;
+		}
+		m->m_data += IF_MAXLINKHDR;
+		m->m_len = hdrlen;
+	}
+
+	ti = mtod(m, struct tcpiphdr *);
+
+	memcpy((caddr_t)ti, &tp->t_template, sizeof (struct tcpiphdr));
+
+	/*
+	 * Fill in fields, remembering maximum advertised
+	 * window for use in delaying messages about window sizes.
+	 * If resending a FIN, be sure not to use a new sequence number.
+	 */
+	if (flags & TH_FIN && tp->t_flags & TF_SENTFIN &&
+	    tp->snd_nxt == tp->snd_max)
+		tp->snd_nxt--;
+	/*
+	 * If we are doing retransmissions, then snd_nxt will
+	 * not reflect the first unsent octet.  For ACK only
+	 * packets, we do not want the sequence number of the
+	 * retransmitted packet, we want the sequence number
+	 * of the next unsent octet.  So, if there is no data
+	 * (and no SYN or FIN), use snd_max instead of snd_nxt
+	 * when filling in ti_seq.  But if we are in persist
+	 * state, snd_max might reflect one byte beyond the
+	 * right edge of the window, so use snd_nxt in that
+	 * case, since we know we aren't doing a retransmission.
+	 * (retransmit and persist are mutually exclusive...)
+	 */
+	if (len || (flags & (TH_SYN|TH_FIN)) || tp->t_timer[TCPT_PERSIST])
+		ti->ti_seq = htonl(tp->snd_nxt);
+	else
+		ti->ti_seq = htonl(tp->snd_max);
+	ti->ti_ack = htonl(tp->rcv_nxt);
+	if (optlen) {
+		memcpy((caddr_t)(ti + 1), (caddr_t)opt, optlen);
+		ti->ti_off = (sizeof (struct tcphdr) + optlen) >> 2;
+	}
+	ti->ti_flags = flags;
+	/*
+	 * Calculate receive window.  Don't shrink window,
+	 * but avoid silly window syndrome.
+	 */
+	if (win < (long)(so->so_rcv.sb_datalen / 4) && win < (long)tp->t_maxseg)
+		win = 0;
+	if (win > (long)TCP_MAXWIN << tp->rcv_scale)
+		win = (long)TCP_MAXWIN << tp->rcv_scale;
+	if (win < (long)(tp->rcv_adv - tp->rcv_nxt))
+		win = (long)(tp->rcv_adv - tp->rcv_nxt);
+	ti->ti_win = htons((uint16_t) (win>>tp->rcv_scale));
+
+	if (SEQ_GT(tp->snd_up, tp->snd_una)) {
+		ti->ti_urp = htons((uint16_t)(tp->snd_up - ntohl(ti->ti_seq)));
+		ti->ti_flags |= TH_URG;
+	} else
+		/*
+		 * If no urgent pointer to send, then we pull
+		 * the urgent pointer to the left edge of the send window
+		 * so that it doesn't drift into the send window on sequence
+		 * number wraparound.
+		 */
+		tp->snd_up = tp->snd_una;		/* drag it along */
+
+	/*
+	 * Put TCP length in extended header, and then
+	 * checksum extended header and data.
+	 */
+	if (len + optlen)
+		ti->ti_len = htons((uint16_t)(sizeof (struct tcphdr) +
+		    optlen + len));
+	ti->ti_sum = cksum(m, (int)(hdrlen + len));
+
+	/*
+	 * In transmit state, time the transmission and arrange for
+	 * the retransmit.  In persist state, just set snd_max.
+	 */
+	if (tp->t_force == 0 || tp->t_timer[TCPT_PERSIST] == 0) {
+		tcp_seq startseq = tp->snd_nxt;
+
+		/*
+		 * Advance snd_nxt over sequence space of this segment.
+		 */
+		if (flags & (TH_SYN|TH_FIN)) {
+			if (flags & TH_SYN)
+				tp->snd_nxt++;
+			if (flags & TH_FIN) {
+				tp->snd_nxt++;
+				tp->t_flags |= TF_SENTFIN;
+			}
+		}
+		tp->snd_nxt += len;
+		if (SEQ_GT(tp->snd_nxt, tp->snd_max)) {
+			tp->snd_max = tp->snd_nxt;
+			/*
+			 * Time this transmission if not a retransmission and
+			 * not currently timing anything.
+			 */
+			if (tp->t_rtt == 0) {
+				tp->t_rtt = 1;
+				tp->t_rtseq = startseq;
+			}
+		}
+
+		/*
+		 * Set retransmit timer if not currently set,
+		 * and not doing an ack or a keep-alive probe.
+		 * Initial value for retransmit timer is smoothed
+		 * round-trip time + 2 * round-trip time variance.
+		 * Initialize shift counter which is used for backoff
+		 * of retransmit time.
+		 */
+		if (tp->t_timer[TCPT_REXMT] == 0 &&
+		    tp->snd_nxt != tp->snd_una) {
+			tp->t_timer[TCPT_REXMT] = tp->t_rxtcur;
+			if (tp->t_timer[TCPT_PERSIST]) {
+				tp->t_timer[TCPT_PERSIST] = 0;
+				tp->t_rxtshift = 0;
+			}
+		}
+	} else
+		if (SEQ_GT(tp->snd_nxt + len, tp->snd_max))
+			tp->snd_max = tp->snd_nxt + len;
+
+	/*
+	 * Fill in IP length and desired time to live and
+	 * send to IP level.  There should be a better way
+	 * to handle ttl and tos; we could keep them in
+	 * the template, but need a way to checksum without them.
+	 */
+	m->m_len = hdrlen + len; /* XXX Needed? m_len should be correct */
+
+    {
+
+	((struct ip *)ti)->ip_len = m->m_len;
+
+	((struct ip *)ti)->ip_ttl = IPDEFTTL;
+	((struct ip *)ti)->ip_tos = so->so_iptos;
+
+	error = ip_output(so, m);
+    }
+	if (error) {
+out:
+		return (error);
+	}
+
+	/*
+	 * Data sent (as far as we can tell).
+	 * If this advertises a larger window than any other segment,
+	 * then remember the size of the advertised window.
+	 * Any pending ACK has now been sent.
+	 */
+	if (win > 0 && SEQ_GT(tp->rcv_nxt+win, tp->rcv_adv))
+		tp->rcv_adv = tp->rcv_nxt + win;
+	tp->last_ack_sent = tp->rcv_nxt;
+	tp->t_flags &= ~(TF_ACKNOW|TF_DELACK);
+	if (sendalot)
+		goto again;
+
+	return (0);
+}
+
+void
+tcp_setpersist(struct tcpcb *tp)
+{
+    int t = ((tp->t_srtt >> 2) + tp->t_rttvar) >> 1;
+
+	/*
+	 * Start/restart persistence timer.
+	 */
+	TCPT_RANGESET(tp->t_timer[TCPT_PERSIST],
+	    t * tcp_backoff[tp->t_rxtshift],
+	    TCPTV_PERSMIN, TCPTV_PERSMAX);
+	if (tp->t_rxtshift < TCP_MAXRXTSHIFT)
+		tp->t_rxtshift++;
+}
diff --git a/src/slirp/tcp_subr.c b/src/slirp/tcp_subr.c
new file mode 100644
index 0000000..e161ed2
--- /dev/null
+++ b/src/slirp/tcp_subr.c
@@ -0,0 +1,926 @@
+/*
+ * Copyright (c) 1982, 1986, 1988, 1990, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)tcp_subr.c	8.1 (Berkeley) 6/10/93
+ * tcp_subr.c,v 1.5 1994/10/08 22:39:58 phk Exp
+ */
+
+/*
+ * Changes and additions relating to SLiRP
+ * Copyright (c) 1995 Danny Gasparovski.
+ *
+ * Please read the file COPYRIGHT for the
+ * terms and conditions of the copyright.
+ */
+
+#include <slirp.h>
+
+/* patchable/settable parameters for tcp */
+/* Don't do rfc1323 performance enhancements */
+#define TCP_DO_RFC1323 0
+
+/*
+ * Tcp initialization
+ */
+void
+tcp_init(Slirp *slirp)
+{
+    slirp->tcp_iss = 1;		/* wrong */
+    slirp->tcb.so_next = slirp->tcb.so_prev = &slirp->tcb;
+    slirp->tcp_last_so = &slirp->tcb;
+}
+
+void tcp_cleanup(Slirp *slirp)
+{
+    while (slirp->tcb.so_next != &slirp->tcb) {
+        tcp_close(sototcpcb(slirp->tcb.so_next));
+    }
+}
+
+/*
+ * Create template to be used to send tcp packets on a connection.
+ * Call after host entry created, fills
+ * in a skeletal tcp/ip header, minimizing the amount of work
+ * necessary when the connection is used.
+ */
+void
+tcp_template(struct tcpcb *tp)
+{
+	struct socket *so = tp->t_socket;
+	register struct tcpiphdr *n = &tp->t_template;
+
+	n->ti_mbuf = NULL;
+	n->ti_x1 = 0;
+	n->ti_pr = IPPROTO_TCP;
+	n->ti_len = htons(sizeof (struct tcpiphdr) - sizeof (struct ip));
+	n->ti_src = so->so_faddr;
+	n->ti_dst = so->so_laddr;
+	n->ti_sport = so->so_fport;
+	n->ti_dport = so->so_lport;
+
+	n->ti_seq = 0;
+	n->ti_ack = 0;
+	n->ti_x2 = 0;
+	n->ti_off = 5;
+	n->ti_flags = 0;
+	n->ti_win = 0;
+	n->ti_sum = 0;
+	n->ti_urp = 0;
+}
+
+/*
+ * Send a single message to the TCP at address specified by
+ * the given TCP/IP header.  If m == 0, then we make a copy
+ * of the tcpiphdr at ti and send directly to the addressed host.
+ * This is used to force keep alive messages out using the TCP
+ * template for a connection tp->t_template.  If flags are given
+ * then we send a message back to the TCP which originated the
+ * segment ti, and discard the mbuf containing it and any other
+ * attached mbufs.
+ *
+ * In any case the ack and sequence number of the transmitted
+ * segment are as specified by the parameters.
+ */
+void
+tcp_respond(struct tcpcb *tp, struct tcpiphdr *ti, struct mbuf *m,
+            tcp_seq ack, tcp_seq seq, int flags)
+{
+	register int tlen;
+	int win = 0;
+
+	DEBUG_CALL("tcp_respond");
+	DEBUG_ARG("tp = %p", tp);
+	DEBUG_ARG("ti = %p", ti);
+	DEBUG_ARG("m = %p", m);
+	DEBUG_ARG("ack = %u", ack);
+	DEBUG_ARG("seq = %u", seq);
+	DEBUG_ARG("flags = %x", flags);
+
+	if (tp)
+		win = sbspace(&tp->t_socket->so_rcv);
+        if (m == NULL) {
+		if (!tp || (m = m_get(tp->t_socket->slirp)) == NULL)
+			return;
+		tlen = 0;
+		m->m_data += IF_MAXLINKHDR;
+		*mtod(m, struct tcpiphdr *) = *ti;
+		ti = mtod(m, struct tcpiphdr *);
+		flags = TH_ACK;
+	} else {
+		/*
+		 * ti points into m so the next line is just making
+		 * the mbuf point to ti
+		 */
+		m->m_data = (caddr_t)ti;
+
+		m->m_len = sizeof (struct tcpiphdr);
+		tlen = 0;
+#define xchg(a,b,type) { type t; t=a; a=b; b=t; }
+		xchg(ti->ti_dst.s_addr, ti->ti_src.s_addr, uint32_t);
+		xchg(ti->ti_dport, ti->ti_sport, uint16_t);
+#undef xchg
+	}
+	ti->ti_len = htons((u_short)(sizeof (struct tcphdr) + tlen));
+	tlen += sizeof (struct tcpiphdr);
+	m->m_len = tlen;
+
+        ti->ti_mbuf = NULL;
+	ti->ti_x1 = 0;
+	ti->ti_seq = htonl(seq);
+	ti->ti_ack = htonl(ack);
+	ti->ti_x2 = 0;
+	ti->ti_off = sizeof (struct tcphdr) >> 2;
+	ti->ti_flags = flags;
+	if (tp)
+		ti->ti_win = htons((uint16_t) (win >> tp->rcv_scale));
+	else
+		ti->ti_win = htons((uint16_t)win);
+	ti->ti_urp = 0;
+	ti->ti_sum = 0;
+	ti->ti_sum = cksum(m, tlen);
+	((struct ip *)ti)->ip_len = tlen;
+
+	if(flags & TH_RST)
+	  ((struct ip *)ti)->ip_ttl = MAXTTL;
+	else
+	  ((struct ip *)ti)->ip_ttl = IPDEFTTL;
+
+	(void) ip_output((struct socket *)0, m);
+}
+
+/*
+ * Create a new TCP control block, making an
+ * empty reassembly queue and hooking it to the argument
+ * protocol control block.
+ */
+struct tcpcb *
+tcp_newtcpcb(struct socket *so)
+{
+	register struct tcpcb *tp;
+
+	tp = (struct tcpcb *)malloc(sizeof(*tp));
+	if (tp == NULL)
+		return ((struct tcpcb *)0);
+
+	memset((char *) tp, 0, sizeof(struct tcpcb));
+	tp->seg_next = tp->seg_prev = (struct tcpiphdr*)tp;
+	tp->t_maxseg = TCP_MSS;
+
+	tp->t_flags = TCP_DO_RFC1323 ? (TF_REQ_SCALE|TF_REQ_TSTMP) : 0;
+	tp->t_socket = so;
+
+	/*
+	 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no
+	 * rtt estimate.  Set rttvar so that srtt + 2 * rttvar gives
+	 * reasonable initial retransmit time.
+	 */
+	tp->t_srtt = TCPTV_SRTTBASE;
+	tp->t_rttvar = TCPTV_SRTTDFLT << 2;
+	tp->t_rttmin = TCPTV_MIN;
+
+	TCPT_RANGESET(tp->t_rxtcur,
+	    ((TCPTV_SRTTBASE >> 2) + (TCPTV_SRTTDFLT << 2)) >> 1,
+	    TCPTV_MIN, TCPTV_REXMTMAX);
+
+	tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT;
+	tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT;
+	tp->t_state = TCPS_CLOSED;
+
+	so->so_tcpcb = tp;
+
+	return (tp);
+}
+
+/*
+ * Drop a TCP connection, reporting
+ * the specified error.  If connection is synchronized,
+ * then send a RST to peer.
+ */
+struct tcpcb *tcp_drop(struct tcpcb *tp, int err)
+{
+	DEBUG_CALL("tcp_drop");
+	DEBUG_ARG("tp = %p", tp);
+	DEBUG_ARG("errno = %d", errno);
+
+	if (TCPS_HAVERCVDSYN(tp->t_state)) {
+		tp->t_state = TCPS_CLOSED;
+		(void) tcp_output(tp);
+	}
+	return (tcp_close(tp));
+}
+
+/*
+ * Close a TCP control block:
+ *	discard all space held by the tcp
+ *	discard internet protocol block
+ *	wake up any sleepers
+ */
+struct tcpcb *
+tcp_close(struct tcpcb *tp)
+{
+	register struct tcpiphdr *t;
+	struct socket *so = tp->t_socket;
+	Slirp *slirp = so->slirp;
+	register struct mbuf *m;
+
+	DEBUG_CALL("tcp_close");
+	DEBUG_ARG("tp = %p", tp);
+
+	/* free the reassembly queue, if any */
+	t = tcpfrag_list_first(tp);
+	while (!tcpfrag_list_end(t, tp)) {
+		t = tcpiphdr_next(t);
+		m = tcpiphdr_prev(t)->ti_mbuf;
+		remque(tcpiphdr2qlink(tcpiphdr_prev(t)));
+		m_free(m);
+	}
+	free(tp);
+        so->so_tcpcb = NULL;
+	/* clobber input socket cache if we're closing the cached connection */
+	if (so == slirp->tcp_last_so)
+		slirp->tcp_last_so = &slirp->tcb;
+	closesocket(so->s);
+	sbfree(&so->so_rcv);
+	sbfree(&so->so_snd);
+	sofree(so);
+	return ((struct tcpcb *)0);
+}
+
+/*
+ * TCP protocol interface to socket abstraction.
+ */
+
+/*
+ * User issued close, and wish to trail through shutdown states:
+ * if never received SYN, just forget it.  If got a SYN from peer,
+ * but haven't sent FIN, then go to FIN_WAIT_1 state to send peer a FIN.
+ * If already got a FIN from peer, then almost done; go to LAST_ACK
+ * state.  In all other cases, have already sent FIN to peer (e.g.
+ * after PRU_SHUTDOWN), and just have to play tedious game waiting
+ * for peer to send FIN or not respond to keep-alives, etc.
+ * We can let the user exit from the close as soon as the FIN is acked.
+ */
+void
+tcp_sockclosed(struct tcpcb *tp)
+{
+
+	DEBUG_CALL("tcp_sockclosed");
+	DEBUG_ARG("tp = %p", tp);
+
+	switch (tp->t_state) {
+
+	case TCPS_CLOSED:
+	case TCPS_LISTEN:
+	case TCPS_SYN_SENT:
+		tp->t_state = TCPS_CLOSED;
+		tp = tcp_close(tp);
+		break;
+
+	case TCPS_SYN_RECEIVED:
+	case TCPS_ESTABLISHED:
+		tp->t_state = TCPS_FIN_WAIT_1;
+		break;
+
+	case TCPS_CLOSE_WAIT:
+		tp->t_state = TCPS_LAST_ACK;
+		break;
+	}
+	if (tp)
+		tcp_output(tp);
+}
+
+/*
+ * Connect to a host on the Internet
+ * Called by tcp_input
+ * Only do a connect, the tcp fields will be set in tcp_input
+ * return 0 if there's a result of the connect,
+ * else return -1 means we're still connecting
+ * The return value is almost always -1 since the socket is
+ * nonblocking.  Connect returns after the SYN is sent, and does
+ * not wait for ACK+SYN.
+ */
+int tcp_fconnect(struct socket *so)
+{
+  Slirp *slirp = so->slirp;
+  int ret=0;
+
+  DEBUG_CALL("tcp_fconnect");
+  DEBUG_ARG("so = %p", so);
+
+  if( (ret = so->s = qemu_socket(AF_INET,SOCK_STREAM,0)) >= 0) {
+    int opt, s=so->s;
+    struct sockaddr_in addr;
+
+    qemu_set_nonblock(s);
+    socket_set_fast_reuse(s);
+    opt = 1;
+    qemu_setsockopt(s, SOL_SOCKET, SO_OOBINLINE, &opt, sizeof(opt));
+
+    addr.sin_family = AF_INET;
+    if ((so->so_faddr.s_addr & slirp->vnetwork_mask.s_addr) ==
+        slirp->vnetwork_addr.s_addr) {
+      /* It's an alias */
+      if (so->so_faddr.s_addr == slirp->vnameserver_addr.s_addr) {
+	if (get_dns_addr(&addr.sin_addr) < 0)
+	  addr.sin_addr = loopback_addr;
+      } else {
+	addr.sin_addr = loopback_addr;
+      }
+    } else
+      addr.sin_addr = so->so_faddr;
+    addr.sin_port = so->so_fport;
+
+    DEBUG_MISC((dfd, " connect()ing, addr.sin_port=%d, "
+		"addr.sin_addr.s_addr=%.16s\n",
+		ntohs(addr.sin_port), inet_ntoa(addr.sin_addr)));
+    /* We don't care what port we get */
+    ret = connect(s,(struct sockaddr *)&addr,sizeof (addr));
+
+    /*
+     * If it's not in progress, it failed, so we just return 0,
+     * without clearing SS_NOFDREF
+     */
+    soisfconnecting(so);
+  }
+
+  return(ret);
+}
+
+/*
+ * Accept the socket and connect to the local-host
+ *
+ * We have a problem. The correct thing to do would be
+ * to first connect to the local-host, and only if the
+ * connection is accepted, then do an accept() here.
+ * But, a) we need to know who's trying to connect
+ * to the socket to be able to SYN the local-host, and
+ * b) we are already connected to the foreign host by
+ * the time it gets to accept(), so... We simply accept
+ * here and SYN the local-host.
+ */
+void tcp_connect(struct socket *inso)
+{
+    Slirp *slirp = inso->slirp;
+    struct socket *so;
+    struct sockaddr_in addr;
+    socklen_t addrlen = sizeof(struct sockaddr_in);
+    struct tcpcb *tp;
+    int s, opt;
+
+    DEBUG_CALL("tcp_connect");
+    DEBUG_ARG("inso = %p", inso);
+
+    /*
+     * If it's an SS_ACCEPTONCE socket, no need to socreate()
+     * another socket, just use the accept() socket.
+     */
+    if (inso->so_state & SS_FACCEPTONCE) {
+        /* FACCEPTONCE already have a tcpcb */
+        so = inso;
+    } else {
+        so = socreate(slirp);
+        if (so == NULL) {
+            /* If it failed, get rid of the pending connection */
+            closesocket(accept(inso->s, (struct sockaddr *)&addr, &addrlen));
+            return;
+        }
+        if (tcp_attach(so) < 0) {
+            free(so); /* NOT sofree */
+            return;
+        }
+        so->so_laddr = inso->so_laddr;
+        so->so_lport = inso->so_lport;
+    }
+
+    tcp_mss(sototcpcb(so), 0);
+
+    s = accept(inso->s, (struct sockaddr *)&addr, &addrlen);
+    if (s < 0) {
+        tcp_close(sototcpcb(so)); /* This will sofree() as well */
+        return;
+    }
+    qemu_set_nonblock(s);
+    socket_set_fast_reuse(s);
+    opt = 1;
+    qemu_setsockopt(s, SOL_SOCKET, SO_OOBINLINE, &opt, sizeof(int));
+    socket_set_nodelay(s);
+
+    so->so_fport = addr.sin_port;
+    so->so_faddr = addr.sin_addr;
+    /* Translate connections from localhost to the real hostname */
+    if (so->so_faddr.s_addr == 0 ||
+        (so->so_faddr.s_addr & loopback_mask) ==
+        (loopback_addr.s_addr & loopback_mask)) {
+        so->so_faddr = slirp->vhost_addr;
+    }
+
+    /* Close the accept() socket, set right state */
+    if (inso->so_state & SS_FACCEPTONCE) {
+        /* If we only accept once, close the accept() socket */
+        closesocket(so->s);
+
+        /* Don't select it yet, even though we have an FD */
+        /* if it's not FACCEPTONCE, it's already NOFDREF */
+        so->so_state = SS_NOFDREF;
+    }
+    so->s = s;
+    so->so_state |= SS_INCOMING;
+
+    so->so_iptos = tcp_tos(so);
+    tp = sototcpcb(so);
+
+    tcp_template(tp);
+
+    tp->t_state = TCPS_SYN_SENT;
+    tp->t_timer[TCPT_KEEP] = TCPTV_KEEP_INIT;
+    tp->iss = slirp->tcp_iss;
+    slirp->tcp_iss += TCP_ISSINCR/2;
+    tcp_sendseqinit(tp);
+    tcp_output(tp);
+}
+
+/*
+ * Attach a TCPCB to a socket.
+ */
+int
+tcp_attach(struct socket *so)
+{
+	if ((so->so_tcpcb = tcp_newtcpcb(so)) == NULL)
+	   return -1;
+
+	insque(so, &so->slirp->tcb);
+
+	return 0;
+}
+
+/*
+ * Set the socket's type of service field
+ */
+static const struct tos_t tcptos[] = {
+	  {0, 20, IPTOS_THROUGHPUT, 0},	/* ftp data */
+	  {21, 21, IPTOS_LOWDELAY,  EMU_FTP},	/* ftp control */
+	  {0, 23, IPTOS_LOWDELAY, 0},	/* telnet */
+	  {0, 80, IPTOS_THROUGHPUT, 0},	/* WWW */
+	  {0, 513, IPTOS_LOWDELAY, EMU_RLOGIN|EMU_NOCONNECT},	/* rlogin */
+	  {0, 514, IPTOS_LOWDELAY, EMU_RSH|EMU_NOCONNECT},	/* shell */
+	  {0, 544, IPTOS_LOWDELAY, EMU_KSH},		/* kshell */
+	  {0, 543, IPTOS_LOWDELAY, 0},	/* klogin */
+	  {0, 6667, IPTOS_THROUGHPUT, EMU_IRC},	/* IRC */
+	  {0, 6668, IPTOS_THROUGHPUT, EMU_IRC},	/* IRC undernet */
+	  {0, 7070, IPTOS_LOWDELAY, EMU_REALAUDIO }, /* RealAudio control */
+	  {0, 113, IPTOS_LOWDELAY, EMU_IDENT }, /* identd protocol */
+	  {0, 0, 0, 0}
+};
+
+static struct emu_t *tcpemu = NULL;
+
+/*
+ * Return TOS according to the above table
+ */
+uint8_t
+tcp_tos(struct socket *so)
+{
+	int i = 0;
+	struct emu_t *emup;
+
+	while(tcptos[i].tos) {
+		if ((tcptos[i].fport && (ntohs(so->so_fport) == tcptos[i].fport)) ||
+		    (tcptos[i].lport && (ntohs(so->so_lport) == tcptos[i].lport))) {
+			so->so_emu = tcptos[i].emu;
+			return tcptos[i].tos;
+		}
+		i++;
+	}
+
+	/* Nope, lets see if there's a user-added one */
+	for (emup = tcpemu; emup; emup = emup->next) {
+		if ((emup->fport && (ntohs(so->so_fport) == emup->fport)) ||
+		    (emup->lport && (ntohs(so->so_lport) == emup->lport))) {
+			so->so_emu = emup->emu;
+			return emup->tos;
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * Emulate programs that try and connect to us
+ * This includes ftp (the data connection is
+ * initiated by the server) and IRC (DCC CHAT and
+ * DCC SEND) for now
+ *
+ * NOTE: It's possible to crash SLiRP by sending it
+ * unstandard strings to emulate... if this is a problem,
+ * more checks are needed here
+ *
+ * XXX Assumes the whole command came in one packet
+ *
+ * XXX Some ftp clients will have their TOS set to
+ * LOWDELAY and so Nagel will kick in.  Because of this,
+ * we'll get the first letter, followed by the rest, so
+ * we simply scan for ORT instead of PORT...
+ * DCC doesn't have this problem because there's other stuff
+ * in the packet before the DCC command.
+ *
+ * Return 1 if the mbuf m is still valid and should be
+ * sbappend()ed
+ *
+ * NOTE: if you return 0 you MUST m_free() the mbuf!
+ */
+int
+tcp_emu(struct socket *so, struct mbuf *m)
+{
+	Slirp *slirp = so->slirp;
+	u_int n1, n2, n3, n4, n5, n6;
+        char buff[257];
+	uint32_t laddr;
+	u_int lport;
+	char *bptr;
+
+	DEBUG_CALL("tcp_emu");
+	DEBUG_ARG("so = %p", so);
+	DEBUG_ARG("m = %p", m);
+
+	switch(so->so_emu) {
+		int x, i;
+
+	 case EMU_IDENT:
+		/*
+		 * Identification protocol as per rfc-1413
+		 */
+
+		{
+			struct socket *tmpso;
+			struct sockaddr_in addr;
+			socklen_t addrlen = sizeof(struct sockaddr_in);
+			struct sbuf *so_rcv = &so->so_rcv;
+
+			memcpy(so_rcv->sb_wptr, m->m_data, m->m_len);
+			so_rcv->sb_wptr += m->m_len;
+			so_rcv->sb_rptr += m->m_len;
+			m->m_data[m->m_len] = 0; /* NULL terminate */
+			if (strchr(m->m_data, '\r') || strchr(m->m_data, '\n')) {
+				if (sscanf(so_rcv->sb_data, "%u%*[ ,]%u", &n1, &n2) == 2) {
+					HTONS(n1);
+					HTONS(n2);
+					/* n2 is the one on our host */
+					for (tmpso = slirp->tcb.so_next;
+					     tmpso != &slirp->tcb;
+					     tmpso = tmpso->so_next) {
+						if (tmpso->so_laddr.s_addr == so->so_laddr.s_addr &&
+						    tmpso->so_lport == n2 &&
+						    tmpso->so_faddr.s_addr == so->so_faddr.s_addr &&
+						    tmpso->so_fport == n1) {
+							if (getsockname(tmpso->s,
+								(struct sockaddr *)&addr, &addrlen) == 0)
+							   n2 = ntohs(addr.sin_port);
+							break;
+						}
+					}
+				}
+                                so_rcv->sb_cc = snprintf(so_rcv->sb_data,
+                                                         so_rcv->sb_datalen,
+                                                         "%d,%d\r\n", n1, n2);
+				so_rcv->sb_rptr = so_rcv->sb_data;
+				so_rcv->sb_wptr = so_rcv->sb_data + so_rcv->sb_cc;
+			}
+			m_free(m);
+			return 0;
+		}
+
+        case EMU_FTP: /* ftp */
+                *(m->m_data+m->m_len) = 0; /* NUL terminate for strstr */
+		if ((bptr = (char *)strstr(m->m_data, "ORT")) != NULL) {
+			/*
+			 * Need to emulate the PORT command
+			 */
+			x = sscanf(bptr, "ORT %u,%u,%u,%u,%u,%u\r\n%256[^\177]",
+				   &n1, &n2, &n3, &n4, &n5, &n6, buff);
+			if (x < 6)
+			   return 1;
+
+			laddr = htonl((n1 << 24) | (n2 << 16) | (n3 << 8) | (n4));
+			lport = htons((n5 << 8) | (n6));
+
+			if ((so = tcp_listen(slirp, INADDR_ANY, 0, laddr,
+			                     lport, SS_FACCEPTONCE)) == NULL) {
+			   return 1;
+			}
+			n6 = ntohs(so->so_fport);
+
+			n5 = (n6 >> 8) & 0xff;
+			n6 &= 0xff;
+
+			laddr = ntohl(so->so_faddr.s_addr);
+
+			n1 = ((laddr >> 24) & 0xff);
+			n2 = ((laddr >> 16) & 0xff);
+			n3 = ((laddr >> 8)  & 0xff);
+			n4 =  (laddr & 0xff);
+
+			m->m_len = bptr - m->m_data; /* Adjust length */
+                        m->m_len += snprintf(bptr, m->m_size - m->m_len,
+                                             "ORT %d,%d,%d,%d,%d,%d\r\n%s",
+                                             n1, n2, n3, n4, n5, n6, x==7?buff:"");
+			return 1;
+		} else if ((bptr = (char *)strstr(m->m_data, "27 Entering")) != NULL) {
+			/*
+			 * Need to emulate the PASV response
+			 */
+			x = sscanf(bptr, "27 Entering Passive Mode (%u,%u,%u,%u,%u,%u)\r\n%256[^\177]",
+				   &n1, &n2, &n3, &n4, &n5, &n6, buff);
+			if (x < 6)
+			   return 1;
+
+			laddr = htonl((n1 << 24) | (n2 << 16) | (n3 << 8) | (n4));
+			lport = htons((n5 << 8) | (n6));
+
+			if ((so = tcp_listen(slirp, INADDR_ANY, 0, laddr,
+			                     lport, SS_FACCEPTONCE)) == NULL) {
+			   return 1;
+			}
+			n6 = ntohs(so->so_fport);
+
+			n5 = (n6 >> 8) & 0xff;
+			n6 &= 0xff;
+
+			laddr = ntohl(so->so_faddr.s_addr);
+
+			n1 = ((laddr >> 24) & 0xff);
+			n2 = ((laddr >> 16) & 0xff);
+			n3 = ((laddr >> 8)  & 0xff);
+			n4 =  (laddr & 0xff);
+
+			m->m_len = bptr - m->m_data; /* Adjust length */
+			m->m_len += snprintf(bptr, m->m_size - m->m_len,
+                                             "27 Entering Passive Mode (%d,%d,%d,%d,%d,%d)\r\n%s",
+                                             n1, n2, n3, n4, n5, n6, x==7?buff:"");
+
+			return 1;
+		}
+
+		return 1;
+
+	 case EMU_KSH:
+		/*
+		 * The kshell (Kerberos rsh) and shell services both pass
+		 * a local port port number to carry signals to the server
+		 * and stderr to the client.  It is passed at the beginning
+		 * of the connection as a NUL-terminated decimal ASCII string.
+		 */
+		so->so_emu = 0;
+		for (lport = 0, i = 0; i < m->m_len-1; ++i) {
+			if (m->m_data[i] < '0' || m->m_data[i] > '9')
+				return 1;       /* invalid number */
+			lport *= 10;
+			lport += m->m_data[i] - '0';
+		}
+		if (m->m_data[m->m_len-1] == '\0' && lport != 0 &&
+		    (so = tcp_listen(slirp, INADDR_ANY, 0, so->so_laddr.s_addr,
+		                     htons(lport), SS_FACCEPTONCE)) != NULL)
+                    m->m_len = snprintf(m->m_data, m->m_size, "%d",
+                                        ntohs(so->so_fport)) + 1;
+		return 1;
+
+	 case EMU_IRC:
+		/*
+		 * Need to emulate DCC CHAT, DCC SEND and DCC MOVE
+		 */
+		*(m->m_data+m->m_len) = 0; /* NULL terminate the string for strstr */
+		if ((bptr = (char *)strstr(m->m_data, "DCC")) == NULL)
+			 return 1;
+
+		/* The %256s is for the broken mIRC */
+		if (sscanf(bptr, "DCC CHAT %256s %u %u", buff, &laddr, &lport) == 3) {
+			if ((so = tcp_listen(slirp, INADDR_ANY, 0,
+			                     htonl(laddr), htons(lport),
+			                     SS_FACCEPTONCE)) == NULL) {
+				return 1;
+			}
+			m->m_len = bptr - m->m_data; /* Adjust length */
+                        m->m_len += snprintf(bptr, m->m_size,
+                                             "DCC CHAT chat %lu %u%c\n",
+                                             (unsigned long)ntohl(so->so_faddr.s_addr),
+                                             ntohs(so->so_fport), 1);
+		} else if (sscanf(bptr, "DCC SEND %256s %u %u %u", buff, &laddr, &lport, &n1) == 4) {
+			if ((so = tcp_listen(slirp, INADDR_ANY, 0,
+			                     htonl(laddr), htons(lport),
+			                     SS_FACCEPTONCE)) == NULL) {
+				return 1;
+			}
+			m->m_len = bptr - m->m_data; /* Adjust length */
+                        m->m_len += snprintf(bptr, m->m_size,
+                                             "DCC SEND %s %lu %u %u%c\n", buff,
+                                             (unsigned long)ntohl(so->so_faddr.s_addr),
+                                             ntohs(so->so_fport), n1, 1);
+		} else if (sscanf(bptr, "DCC MOVE %256s %u %u %u", buff, &laddr, &lport, &n1) == 4) {
+			if ((so = tcp_listen(slirp, INADDR_ANY, 0,
+			                     htonl(laddr), htons(lport),
+			                     SS_FACCEPTONCE)) == NULL) {
+				return 1;
+			}
+			m->m_len = bptr - m->m_data; /* Adjust length */
+                        m->m_len += snprintf(bptr, m->m_size,
+                                             "DCC MOVE %s %lu %u %u%c\n", buff,
+                                             (unsigned long)ntohl(so->so_faddr.s_addr),
+                                             ntohs(so->so_fport), n1, 1);
+		}
+		return 1;
+
+	 case EMU_REALAUDIO:
+                /*
+		 * RealAudio emulation - JP. We must try to parse the incoming
+		 * data and try to find the two characters that contain the
+		 * port number. Then we redirect an udp port and replace the
+		 * number with the real port we got.
+		 *
+		 * The 1.0 beta versions of the player are not supported
+		 * any more.
+		 *
+		 * A typical packet for player version 1.0 (release version):
+		 *
+		 * 0000:50 4E 41 00 05
+		 * 0000:00 01 00 02 1B D7 00 00 67 E6 6C DC 63 00 12 50 ........g.l.c..P
+		 * 0010:4E 43 4C 49 45 4E 54 20 31 30 31 20 41 4C 50 48 NCLIENT 101 ALPH
+		 * 0020:41 6C 00 00 52 00 17 72 61 66 69 6C 65 73 2F 76 Al..R..rafiles/v
+		 * 0030:6F 61 2F 65 6E 67 6C 69 73 68 5F 2E 72 61 79 42 oa/english_.rayB
+		 *
+		 * Now the port number 0x1BD7 is found at offset 0x04 of the
+		 * Now the port number 0x1BD7 is found at offset 0x04 of the
+		 * second packet. This time we received five bytes first and
+		 * then the rest. You never know how many bytes you get.
+		 *
+		 * A typical packet for player version 2.0 (beta):
+		 *
+		 * 0000:50 4E 41 00 06 00 02 00 00 00 01 00 02 1B C1 00 PNA.............
+		 * 0010:00 67 75 78 F5 63 00 0A 57 69 6E 32 2E 30 2E 30 .gux.c..Win2.0.0
+		 * 0020:2E 35 6C 00 00 52 00 1C 72 61 66 69 6C 65 73 2F .5l..R..rafiles/
+		 * 0030:77 65 62 73 69 74 65 2F 32 30 72 65 6C 65 61 73 website/20releas
+		 * 0040:65 2E 72 61 79 53 00 00 06 36 42                e.rayS...6B
+		 *
+		 * Port number 0x1BC1 is found at offset 0x0d.
+		 *
+		 * This is just a horrible switch statement. Variable ra tells
+		 * us where we're going.
+		 */
+
+		bptr = m->m_data;
+		while (bptr < m->m_data + m->m_len) {
+			u_short p;
+			static int ra = 0;
+			char ra_tbl[4];
+
+			ra_tbl[0] = 0x50;
+			ra_tbl[1] = 0x4e;
+			ra_tbl[2] = 0x41;
+			ra_tbl[3] = 0;
+
+			switch (ra) {
+			 case 0:
+			 case 2:
+			 case 3:
+				if (*bptr++ != ra_tbl[ra]) {
+					ra = 0;
+					continue;
+				}
+				break;
+
+			 case 1:
+				/*
+				 * We may get 0x50 several times, ignore them
+				 */
+				if (*bptr == 0x50) {
+					ra = 1;
+					bptr++;
+					continue;
+				} else if (*bptr++ != ra_tbl[ra]) {
+					ra = 0;
+					continue;
+				}
+				break;
+
+			 case 4:
+				/*
+				 * skip version number
+				 */
+				bptr++;
+				break;
+
+			 case 5:
+				/*
+				 * The difference between versions 1.0 and
+				 * 2.0 is here. For future versions of
+				 * the player this may need to be modified.
+				 */
+				if (*(bptr + 1) == 0x02)
+				   bptr += 8;
+				else
+				   bptr += 4;
+				break;
+
+			 case 6:
+				/* This is the field containing the port
+				 * number that RA-player is listening to.
+				 */
+				lport = (((u_char*)bptr)[0] << 8)
+				+ ((u_char *)bptr)[1];
+				if (lport < 6970)
+				   lport += 256;   /* don't know why */
+				if (lport < 6970 || lport > 7170)
+				   return 1;       /* failed */
+
+				/* try to get udp port between 6970 - 7170 */
+				for (p = 6970; p < 7071; p++) {
+					if (udp_listen(slirp, INADDR_ANY,
+						       htons(p),
+						       so->so_laddr.s_addr,
+						       htons(lport),
+						       SS_FACCEPTONCE)) {
+						break;
+					}
+				}
+				if (p == 7071)
+				   p = 0;
+				*(u_char *)bptr++ = (p >> 8) & 0xff;
+                                *(u_char *)bptr = p & 0xff;
+				ra = 0;
+				return 1;   /* port redirected, we're done */
+				break;
+
+			 default:
+				ra = 0;
+			}
+			ra++;
+		}
+		return 1;
+
+	 default:
+		/* Ooops, not emulated, won't call tcp_emu again */
+		so->so_emu = 0;
+		return 1;
+	}
+}
+
+/*
+ * Do misc. config of SLiRP while its running.
+ * Return 0 if this connections is to be closed, 1 otherwise,
+ * return 2 if this is a command-line connection
+ */
+int tcp_ctl(struct socket *so)
+{
+    Slirp *slirp = so->slirp;
+    struct sbuf *sb = &so->so_snd;
+    struct ex_list *ex_ptr;
+    int do_pty;
+
+    DEBUG_CALL("tcp_ctl");
+    DEBUG_ARG("so = %p", so);
+
+    if (so->so_faddr.s_addr != slirp->vhost_addr.s_addr) {
+        /* Check if it's pty_exec */
+        for (ex_ptr = slirp->exec_list; ex_ptr; ex_ptr = ex_ptr->ex_next) {
+            if (ex_ptr->ex_fport == so->so_fport &&
+                so->so_faddr.s_addr == ex_ptr->ex_addr.s_addr) {
+                if (ex_ptr->ex_pty == 3) {
+                    so->s = -1;
+                    so->extra = (void *)ex_ptr->ex_exec;
+                    return 1;
+                }
+                do_pty = ex_ptr->ex_pty;
+                DEBUG_MISC((dfd, " executing %s\n", ex_ptr->ex_exec));
+                return fork_exec(so, ex_ptr->ex_exec, do_pty);
+            }
+        }
+    }
+    sb->sb_cc =
+        snprintf(sb->sb_wptr, sb->sb_datalen - (sb->sb_wptr - sb->sb_data),
+                 "Error: No application configured.\r\n");
+    sb->sb_wptr += sb->sb_cc;
+    return 0;
+}
diff --git a/src/slirp/tcp_timer.c b/src/slirp/tcp_timer.c
new file mode 100644
index 0000000..6c5bb11
--- /dev/null
+++ b/src/slirp/tcp_timer.c
@@ -0,0 +1,292 @@
+/*
+ * Copyright (c) 1982, 1986, 1988, 1990, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)tcp_timer.c	8.1 (Berkeley) 6/10/93
+ * tcp_timer.c,v 1.2 1994/08/02 07:49:10 davidg Exp
+ */
+
+#include <slirp.h>
+
+static struct tcpcb *tcp_timers(register struct tcpcb *tp, int timer);
+
+/*
+ * Fast timeout routine for processing delayed acks
+ */
+void
+tcp_fasttimo(Slirp *slirp)
+{
+	register struct socket *so;
+	register struct tcpcb *tp;
+
+	DEBUG_CALL("tcp_fasttimo");
+
+	so = slirp->tcb.so_next;
+	if (so)
+	for (; so != &slirp->tcb; so = so->so_next)
+		if ((tp = (struct tcpcb *)so->so_tcpcb) &&
+		    (tp->t_flags & TF_DELACK)) {
+			tp->t_flags &= ~TF_DELACK;
+			tp->t_flags |= TF_ACKNOW;
+			(void) tcp_output(tp);
+		}
+}
+
+/*
+ * Tcp protocol timeout routine called every 500 ms.
+ * Updates the timers in all active tcb's and
+ * causes finite state machine actions if timers expire.
+ */
+void
+tcp_slowtimo(Slirp *slirp)
+{
+	register struct socket *ip, *ipnxt;
+	register struct tcpcb *tp;
+	register int i;
+
+	DEBUG_CALL("tcp_slowtimo");
+
+	/*
+	 * Search through tcb's and update active timers.
+	 */
+	ip = slirp->tcb.so_next;
+        if (ip == NULL) {
+            return;
+        }
+	for (; ip != &slirp->tcb; ip = ipnxt) {
+		ipnxt = ip->so_next;
+		tp = sototcpcb(ip);
+                if (tp == NULL) {
+                        continue;
+                }
+		for (i = 0; i < TCPT_NTIMERS; i++) {
+			if (tp->t_timer[i] && --tp->t_timer[i] == 0) {
+				tcp_timers(tp,i);
+				if (ipnxt->so_prev != ip)
+					goto tpgone;
+			}
+		}
+		tp->t_idle++;
+		if (tp->t_rtt)
+		   tp->t_rtt++;
+tpgone:
+		;
+	}
+	slirp->tcp_iss += TCP_ISSINCR/PR_SLOWHZ;	/* increment iss */
+	slirp->tcp_now++;				/* for timestamps */
+}
+
+/*
+ * Cancel all timers for TCP tp.
+ */
+void
+tcp_canceltimers(struct tcpcb *tp)
+{
+	register int i;
+
+	for (i = 0; i < TCPT_NTIMERS; i++)
+		tp->t_timer[i] = 0;
+}
+
+const int tcp_backoff[TCP_MAXRXTSHIFT + 1] =
+   { 1, 2, 4, 8, 16, 32, 64, 64, 64, 64, 64, 64, 64 };
+
+/*
+ * TCP timer processing.
+ */
+static struct tcpcb *
+tcp_timers(register struct tcpcb *tp, int timer)
+{
+	register int rexmt;
+
+	DEBUG_CALL("tcp_timers");
+
+	switch (timer) {
+
+	/*
+	 * 2 MSL timeout in shutdown went off.  If we're closed but
+	 * still waiting for peer to close and connection has been idle
+	 * too long, or if 2MSL time is up from TIME_WAIT, delete connection
+	 * control block.  Otherwise, check again in a bit.
+	 */
+	case TCPT_2MSL:
+		if (tp->t_state != TCPS_TIME_WAIT &&
+		    tp->t_idle <= TCP_MAXIDLE)
+			tp->t_timer[TCPT_2MSL] = TCPTV_KEEPINTVL;
+		else
+			tp = tcp_close(tp);
+		break;
+
+	/*
+	 * Retransmission timer went off.  Message has not
+	 * been acked within retransmit interval.  Back off
+	 * to a longer retransmit interval and retransmit one segment.
+	 */
+	case TCPT_REXMT:
+
+		/*
+		 * XXXXX If a packet has timed out, then remove all the queued
+		 * packets for that session.
+		 */
+
+		if (++tp->t_rxtshift > TCP_MAXRXTSHIFT) {
+			/*
+			 * This is a hack to suit our terminal server here at the uni of canberra
+			 * since they have trouble with zeroes... It usually lets them through
+			 * unharmed, but under some conditions, it'll eat the zeros.  If we
+			 * keep retransmitting it, it'll keep eating the zeroes, so we keep
+			 * retransmitting, and eventually the connection dies...
+			 * (this only happens on incoming data)
+			 *
+			 * So, if we were gonna drop the connection from too many retransmits,
+			 * don't... instead halve the t_maxseg, which might break up the NULLs and
+			 * let them through
+			 *
+			 * *sigh*
+			 */
+
+			tp->t_maxseg >>= 1;
+			if (tp->t_maxseg < 32) {
+				/*
+				 * We tried our best, now the connection must die!
+				 */
+				tp->t_rxtshift = TCP_MAXRXTSHIFT;
+				tp = tcp_drop(tp, tp->t_softerror);
+				/* tp->t_softerror : ETIMEDOUT); */ /* XXX */
+				return (tp); /* XXX */
+			}
+
+			/*
+			 * Set rxtshift to 6, which is still at the maximum
+			 * backoff time
+			 */
+			tp->t_rxtshift = 6;
+		}
+		rexmt = TCP_REXMTVAL(tp) * tcp_backoff[tp->t_rxtshift];
+		TCPT_RANGESET(tp->t_rxtcur, rexmt,
+		    (short)tp->t_rttmin, TCPTV_REXMTMAX); /* XXX */
+		tp->t_timer[TCPT_REXMT] = tp->t_rxtcur;
+		/*
+		 * If losing, let the lower level know and try for
+		 * a better route.  Also, if we backed off this far,
+		 * our srtt estimate is probably bogus.  Clobber it
+		 * so we'll take the next rtt measurement as our srtt;
+		 * move the current srtt into rttvar to keep the current
+		 * retransmit times until then.
+		 */
+		if (tp->t_rxtshift > TCP_MAXRXTSHIFT / 4) {
+			tp->t_rttvar += (tp->t_srtt >> TCP_RTT_SHIFT);
+			tp->t_srtt = 0;
+		}
+		tp->snd_nxt = tp->snd_una;
+		/*
+		 * If timing a segment in this window, stop the timer.
+		 */
+		tp->t_rtt = 0;
+		/*
+		 * Close the congestion window down to one segment
+		 * (we'll open it by one segment for each ack we get).
+		 * Since we probably have a window's worth of unacked
+		 * data accumulated, this "slow start" keeps us from
+		 * dumping all that data as back-to-back packets (which
+		 * might overwhelm an intermediate gateway).
+		 *
+		 * There are two phases to the opening: Initially we
+		 * open by one mss on each ack.  This makes the window
+		 * size increase exponentially with time.  If the
+		 * window is larger than the path can handle, this
+		 * exponential growth results in dropped packet(s)
+		 * almost immediately.  To get more time between
+		 * drops but still "push" the network to take advantage
+		 * of improving conditions, we switch from exponential
+		 * to linear window opening at some threshold size.
+		 * For a threshold, we use half the current window
+		 * size, truncated to a multiple of the mss.
+		 *
+		 * (the minimum cwnd that will give us exponential
+		 * growth is 2 mss.  We don't allow the threshold
+		 * to go below this.)
+		 */
+		{
+		u_int win = min(tp->snd_wnd, tp->snd_cwnd) / 2 / tp->t_maxseg;
+		if (win < 2)
+			win = 2;
+		tp->snd_cwnd = tp->t_maxseg;
+		tp->snd_ssthresh = win * tp->t_maxseg;
+		tp->t_dupacks = 0;
+		}
+		(void) tcp_output(tp);
+		break;
+
+	/*
+	 * Persistence timer into zero window.
+	 * Force a byte to be output, if possible.
+	 */
+	case TCPT_PERSIST:
+		tcp_setpersist(tp);
+		tp->t_force = 1;
+		(void) tcp_output(tp);
+		tp->t_force = 0;
+		break;
+
+	/*
+	 * Keep-alive timer went off; send something
+	 * or drop connection if idle for too long.
+	 */
+	case TCPT_KEEP:
+		if (tp->t_state < TCPS_ESTABLISHED)
+			goto dropit;
+
+		if ((SO_OPTIONS) && tp->t_state <= TCPS_CLOSE_WAIT) {
+		    	if (tp->t_idle >= TCPTV_KEEP_IDLE + TCP_MAXIDLE)
+				goto dropit;
+			/*
+			 * Send a packet designed to force a response
+			 * if the peer is up and reachable:
+			 * either an ACK if the connection is still alive,
+			 * or an RST if the peer has closed the connection
+			 * due to timeout or reboot.
+			 * Using sequence number tp->snd_una-1
+			 * causes the transmitted zero-length segment
+			 * to lie outside the receive window;
+			 * by the protocol spec, this requires the
+			 * correspondent TCP to respond.
+			 */
+			tcp_respond(tp, &tp->t_template, (struct mbuf *)NULL,
+			    tp->rcv_nxt, tp->snd_una - 1, 0);
+			tp->t_timer[TCPT_KEEP] = TCPTV_KEEPINTVL;
+		} else
+			tp->t_timer[TCPT_KEEP] = TCPTV_KEEP_IDLE;
+		break;
+
+	dropit:
+		tp = tcp_drop(tp, 0);
+		break;
+	}
+
+	return (tp);
+}
diff --git a/src/slirp/tcp_timer.h b/src/slirp/tcp_timer.h
new file mode 100644
index 0000000..ff17914
--- /dev/null
+++ b/src/slirp/tcp_timer.h
@@ -0,0 +1,127 @@
+/*
+ * Copyright (c) 1982, 1986, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)tcp_timer.h	8.1 (Berkeley) 6/10/93
+ * tcp_timer.h,v 1.4 1994/08/21 05:27:38 paul Exp
+ */
+
+#ifndef _TCP_TIMER_H_
+#define _TCP_TIMER_H_
+
+/*
+ * Definitions of the TCP timers.  These timers are counted
+ * down PR_SLOWHZ times a second.
+ */
+#define	TCPT_NTIMERS	4
+
+#define	TCPT_REXMT	0		/* retransmit */
+#define	TCPT_PERSIST	1		/* retransmit persistence */
+#define	TCPT_KEEP	2		/* keep alive */
+#define	TCPT_2MSL	3		/* 2*msl quiet time timer */
+
+/*
+ * The TCPT_REXMT timer is used to force retransmissions.
+ * The TCP has the TCPT_REXMT timer set whenever segments
+ * have been sent for which ACKs are expected but not yet
+ * received.  If an ACK is received which advances tp->snd_una,
+ * then the retransmit timer is cleared (if there are no more
+ * outstanding segments) or reset to the base value (if there
+ * are more ACKs expected).  Whenever the retransmit timer goes off,
+ * we retransmit one unacknowledged segment, and do a backoff
+ * on the retransmit timer.
+ *
+ * The TCPT_PERSIST timer is used to keep window size information
+ * flowing even if the window goes shut.  If all previous transmissions
+ * have been acknowledged (so that there are no retransmissions in progress),
+ * and the window is too small to bother sending anything, then we start
+ * the TCPT_PERSIST timer.  When it expires, if the window is nonzero,
+ * we go to transmit state.  Otherwise, at intervals send a single byte
+ * into the peer's window to force him to update our window information.
+ * We do this at most as often as TCPT_PERSMIN time intervals,
+ * but no more frequently than the current estimate of round-trip
+ * packet time.  The TCPT_PERSIST timer is cleared whenever we receive
+ * a window update from the peer.
+ *
+ * The TCPT_KEEP timer is used to keep connections alive.  If an
+ * connection is idle (no segments received) for TCPTV_KEEP_INIT amount of time,
+ * but not yet established, then we drop the connection.  Once the connection
+ * is established, if the connection is idle for TCPTV_KEEP_IDLE time
+ * (and keepalives have been enabled on the socket), we begin to probe
+ * the connection.  We force the peer to send us a segment by sending:
+ *	<SEQ=SND.UNA-1><ACK=RCV.NXT><CTL=ACK>
+ * This segment is (deliberately) outside the window, and should elicit
+ * an ack segment in response from the peer.  If, despite the TCPT_KEEP
+ * initiated segments we cannot elicit a response from a peer in TCPT_MAXIDLE
+ * amount of time probing, then we drop the connection.
+ */
+
+/*
+ * Time constants.
+ */
+#define TCPTV_MSL       ( 5*PR_SLOWHZ)          /* max seg lifetime (hah!) */
+
+#define	TCPTV_SRTTBASE	0			/* base roundtrip time;
+						   if 0, no idea yet */
+#define	TCPTV_SRTTDFLT	(  3*PR_SLOWHZ)		/* assumed RTT if no info */
+
+#define	TCPTV_PERSMIN	(  5*PR_SLOWHZ)		/* retransmit persistence */
+#define	TCPTV_PERSMAX	( 60*PR_SLOWHZ)		/* maximum persist interval */
+
+#define	TCPTV_KEEP_INIT	( 75*PR_SLOWHZ)		/* initial connect keep alive */
+#define	TCPTV_KEEP_IDLE	(120*60*PR_SLOWHZ)	/* dflt time before probing */
+#define	TCPTV_KEEPINTVL	( 75*PR_SLOWHZ)		/* default probe interval */
+#define	TCPTV_KEEPCNT	8			/* max probes before drop */
+
+#define	TCPTV_MIN	(  1*PR_SLOWHZ)		/* minimum allowable value */
+#define TCPTV_REXMTMAX  ( 12*PR_SLOWHZ)		/* max allowable REXMT value */
+
+#define	TCP_LINGERTIME	120			/* linger at most 2 minutes */
+
+#define TCP_MAXRXTSHIFT 12                      /* maximum retransmits */
+
+
+/*
+ * Force a time value to be in a certain range.
+ */
+#define	TCPT_RANGESET(tv, value, tvmin, tvmax) { \
+	(tv) = (value); \
+	if ((tv) < (tvmin)) \
+		(tv) = (tvmin); \
+	else if ((tv) > (tvmax)) \
+		(tv) = (tvmax); \
+}
+
+extern const int tcp_backoff[];
+
+struct tcpcb;
+
+void tcp_fasttimo(Slirp *);
+void tcp_slowtimo(Slirp *);
+void tcp_canceltimers(struct tcpcb *);
+
+#endif
diff --git a/src/slirp/tcp_var.h b/src/slirp/tcp_var.h
new file mode 100644
index 0000000..004193f
--- /dev/null
+++ b/src/slirp/tcp_var.h
@@ -0,0 +1,161 @@
+/*
+ * Copyright (c) 1982, 1986, 1993, 1994
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)tcp_var.h	8.3 (Berkeley) 4/10/94
+ * tcp_var.h,v 1.3 1994/08/21 05:27:39 paul Exp
+ */
+
+#ifndef _TCP_VAR_H_
+#define _TCP_VAR_H_
+
+#include "tcpip.h"
+#include "tcp_timer.h"
+
+/*
+ * Tcp control block, one per tcp; fields:
+ */
+struct tcpcb {
+	struct tcpiphdr *seg_next;	/* sequencing queue */
+	struct tcpiphdr *seg_prev;
+	short	t_state;		/* state of this connection */
+	short	t_timer[TCPT_NTIMERS];	/* tcp timers */
+	short	t_rxtshift;		/* log(2) of rexmt exp. backoff */
+	short	t_rxtcur;		/* current retransmit value */
+	short	t_dupacks;		/* consecutive dup acks recd */
+	u_short	t_maxseg;		/* maximum segment size */
+	char	t_force;		/* 1 if forcing out a byte */
+	u_short	t_flags;
+#define	TF_ACKNOW	0x0001		/* ack peer immediately */
+#define	TF_DELACK	0x0002		/* ack, but try to delay it */
+#define	TF_NODELAY	0x0004		/* don't delay packets to coalesce */
+#define	TF_NOOPT	0x0008		/* don't use tcp options */
+#define	TF_SENTFIN	0x0010		/* have sent FIN */
+#define	TF_REQ_SCALE	0x0020		/* have/will request window scaling */
+#define	TF_RCVD_SCALE	0x0040		/* other side has requested scaling */
+#define	TF_REQ_TSTMP	0x0080		/* have/will request timestamps */
+#define	TF_RCVD_TSTMP	0x0100		/* a timestamp was received in SYN */
+#define	TF_SACK_PERMIT	0x0200		/* other side said I could SACK */
+
+	struct	tcpiphdr t_template;    /* static skeletal packet for xmit */
+
+	struct	socket *t_socket;		/* back pointer to socket */
+/*
+ * The following fields are used as in the protocol specification.
+ * See RFC783, Dec. 1981, page 21.
+ */
+/* send sequence variables */
+	tcp_seq	snd_una;		/* send unacknowledged */
+	tcp_seq	snd_nxt;		/* send next */
+	tcp_seq	snd_up;			/* send urgent pointer */
+	tcp_seq	snd_wl1;		/* window update seg seq number */
+	tcp_seq	snd_wl2;		/* window update seg ack number */
+	tcp_seq	iss;			/* initial send sequence number */
+	uint32_t snd_wnd;		/* send window */
+/* receive sequence variables */
+	uint32_t rcv_wnd;		/* receive window */
+	tcp_seq	rcv_nxt;		/* receive next */
+	tcp_seq	rcv_up;			/* receive urgent pointer */
+	tcp_seq	irs;			/* initial receive sequence number */
+/*
+ * Additional variables for this implementation.
+ */
+/* receive variables */
+	tcp_seq	rcv_adv;		/* advertised window */
+/* retransmit variables */
+	tcp_seq	snd_max;		/* highest sequence number sent;
+					 * used to recognize retransmits
+					 */
+/* congestion control (for slow start, source quench, retransmit after loss) */
+	uint32_t snd_cwnd;		/* congestion-controlled window */
+	uint32_t snd_ssthresh;		/* snd_cwnd size threshold for
+					 * for slow start exponential to
+					 * linear switch
+					 */
+/*
+ * transmit timing stuff.  See below for scale of srtt and rttvar.
+ * "Variance" is actually smoothed difference.
+ */
+	short	t_idle;			/* inactivity time */
+	short	t_rtt;			/* round trip time */
+	tcp_seq	t_rtseq;		/* sequence number being timed */
+	short	t_srtt;			/* smoothed round-trip time */
+	short	t_rttvar;		/* variance in round-trip time */
+	u_short	t_rttmin;		/* minimum rtt allowed */
+	uint32_t max_sndwnd;		/* largest window peer has offered */
+
+/* out-of-band data */
+	char	t_oobflags;		/* have some */
+	char	t_iobc;			/* input character */
+#define	TCPOOB_HAVEDATA	0x01
+#define	TCPOOB_HADDATA	0x02
+	short	t_softerror;		/* possible error not yet reported */
+
+/* RFC 1323 variables */
+	u_char	snd_scale;		/* window scaling for send window */
+	u_char	rcv_scale;		/* window scaling for recv window */
+	u_char	request_r_scale;	/* pending window scaling */
+	u_char	requested_s_scale;
+	uint32_t	ts_recent;		/* timestamp echo data */
+	uint32_t	ts_recent_age;		/* when last updated */
+	tcp_seq	last_ack_sent;
+
+};
+
+#define	sototcpcb(so)	((so)->so_tcpcb)
+
+/*
+ * The smoothed round-trip time and estimated variance
+ * are stored as fixed point numbers scaled by the values below.
+ * For convenience, these scales are also used in smoothing the average
+ * (smoothed = (1/scale)sample + ((scale-1)/scale)smoothed).
+ * With these scales, srtt has 3 bits to the right of the binary point,
+ * and thus an "ALPHA" of 0.875.  rttvar has 2 bits to the right of the
+ * binary point, and is smoothed with an ALPHA of 0.75.
+ */
+#define	TCP_RTT_SCALE		8	/* multiplier for srtt; 3 bits frac. */
+#define	TCP_RTT_SHIFT		3	/* shift for srtt; 3 bits frac. */
+#define	TCP_RTTVAR_SCALE	4	/* multiplier for rttvar; 2 bits */
+#define	TCP_RTTVAR_SHIFT	2	/* multiplier for rttvar; 2 bits */
+
+/*
+ * The initial retransmission should happen at rtt + 4 * rttvar.
+ * Because of the way we do the smoothing, srtt and rttvar
+ * will each average +1/2 tick of bias.  When we compute
+ * the retransmit timer, we want 1/2 tick of rounding and
+ * 1 extra tick because of +-1/2 tick uncertainty in the
+ * firing of the timer.  The bias will give us exactly the
+ * 1.5 tick we need.  But, because the bias is
+ * statistical, we have to test that we don't drop below
+ * the minimum feasible timer (which is 2 ticks).
+ * This macro assumes that the value of TCP_RTTVAR_SCALE
+ * is the same as the multiplier for rttvar.
+ */
+#define	TCP_REXMTVAL(tp) \
+	(((tp)->t_srtt >> TCP_RTT_SHIFT) + (tp)->t_rttvar)
+
+#endif
diff --git a/src/slirp/tcpip.h b/src/slirp/tcpip.h
new file mode 100644
index 0000000..7974ce3
--- /dev/null
+++ b/src/slirp/tcpip.h
@@ -0,0 +1,77 @@
+/*
+ * Copyright (c) 1982, 1986, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)tcpip.h	8.1 (Berkeley) 6/10/93
+ * tcpip.h,v 1.3 1994/08/21 05:27:40 paul Exp
+ */
+
+#ifndef _TCPIP_H_
+#define _TCPIP_H_
+
+/*
+ * Tcp+ip header, after ip options removed.
+ */
+struct tcpiphdr {
+	struct 	ipovly ti_i;		/* overlaid ip structure */
+	struct	tcphdr ti_t;		/* tcp header */
+};
+#define	ti_mbuf		ti_i.ih_mbuf.mptr
+#define	ti_x1		ti_i.ih_x1
+#define	ti_pr		ti_i.ih_pr
+#define	ti_len		ti_i.ih_len
+#define	ti_src		ti_i.ih_src
+#define	ti_dst		ti_i.ih_dst
+#define	ti_sport	ti_t.th_sport
+#define	ti_dport	ti_t.th_dport
+#define	ti_seq		ti_t.th_seq
+#define	ti_ack		ti_t.th_ack
+#define	ti_x2		ti_t.th_x2
+#define	ti_off		ti_t.th_off
+#define	ti_flags	ti_t.th_flags
+#define	ti_win		ti_t.th_win
+#define	ti_sum		ti_t.th_sum
+#define	ti_urp		ti_t.th_urp
+
+#define tcpiphdr2qlink(T) ((struct qlink*)(((char*)(T)) - sizeof(struct qlink)))
+#define qlink2tcpiphdr(Q) ((struct tcpiphdr*)(((char*)(Q)) + sizeof(struct qlink)))
+#define tcpiphdr_next(T) qlink2tcpiphdr(tcpiphdr2qlink(T)->next)
+#define tcpiphdr_prev(T) qlink2tcpiphdr(tcpiphdr2qlink(T)->prev)
+#define tcpfrag_list_first(T) qlink2tcpiphdr((T)->seg_next)
+#define tcpfrag_list_end(F, T) (tcpiphdr2qlink(F) == (struct qlink*)(T))
+#define tcpfrag_list_empty(T) ((T)->seg_next == (struct tcpiphdr*)(T))
+
+/*
+ * Just a clean way to get to the first byte
+ * of the packet
+ */
+struct tcpiphdr_2 {
+	struct tcpiphdr dummy;
+	char first_char;
+};
+
+#endif
diff --git a/src/slirp/tftp.c b/src/slirp/tftp.c
new file mode 100644
index 0000000..a329fb2
--- /dev/null
+++ b/src/slirp/tftp.c
@@ -0,0 +1,442 @@
+/*
+ * tftp.c - a simple, read-only tftp server for qemu
+ *
+ * Copyright (c) 2004 Magnus Damm <damm@opensource.se>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include <slirp.h>
+#include "qemu-common.h"
+
+static inline int tftp_session_in_use(struct tftp_session *spt)
+{
+    return (spt->slirp != NULL);
+}
+
+static inline void tftp_session_update(struct tftp_session *spt)
+{
+    spt->timestamp = curtime;
+}
+
+static void tftp_session_terminate(struct tftp_session *spt)
+{
+    if (spt->fd >= 0) {
+        close(spt->fd);
+        spt->fd = -1;
+    }
+    g_free(spt->filename);
+    spt->slirp = NULL;
+}
+
+static int tftp_session_allocate(Slirp *slirp, struct tftp_t *tp)
+{
+  struct tftp_session *spt;
+  int k;
+
+  for (k = 0; k < TFTP_SESSIONS_MAX; k++) {
+    spt = &slirp->tftp_sessions[k];
+
+    if (!tftp_session_in_use(spt))
+        goto found;
+
+    /* sessions time out after 5 inactive seconds */
+    if ((int)(curtime - spt->timestamp) > 5000) {
+        tftp_session_terminate(spt);
+        goto found;
+    }
+  }
+
+  return -1;
+
+ found:
+  memset(spt, 0, sizeof(*spt));
+  memcpy(&spt->client_ip, &tp->ip.ip_src, sizeof(spt->client_ip));
+  spt->fd = -1;
+  spt->client_port = tp->udp.uh_sport;
+  spt->slirp = slirp;
+
+  tftp_session_update(spt);
+
+  return k;
+}
+
+static int tftp_session_find(Slirp *slirp, struct tftp_t *tp)
+{
+  struct tftp_session *spt;
+  int k;
+
+  for (k = 0; k < TFTP_SESSIONS_MAX; k++) {
+    spt = &slirp->tftp_sessions[k];
+
+    if (tftp_session_in_use(spt)) {
+      if (!memcmp(&spt->client_ip, &tp->ip.ip_src, sizeof(spt->client_ip))) {
+	if (spt->client_port == tp->udp.uh_sport) {
+	  return k;
+	}
+      }
+    }
+  }
+
+  return -1;
+}
+
+static int tftp_read_data(struct tftp_session *spt, uint32_t block_nr,
+                          uint8_t *buf, int len)
+{
+    int bytes_read = 0;
+
+    if (spt->fd < 0) {
+        spt->fd = open(spt->filename, O_RDONLY | O_BINARY);
+    }
+
+    if (spt->fd < 0) {
+        return -1;
+    }
+
+    if (len) {
+        lseek(spt->fd, block_nr * 512, SEEK_SET);
+
+        bytes_read = read(spt->fd, buf, len);
+    }
+
+    return bytes_read;
+}
+
+static int tftp_send_oack(struct tftp_session *spt,
+                          const char *keys[], uint32_t values[], int nb,
+                          struct tftp_t *recv_tp)
+{
+    struct sockaddr_in saddr, daddr;
+    struct mbuf *m;
+    struct tftp_t *tp;
+    int i, n = 0;
+
+    m = m_get(spt->slirp);
+
+    if (!m)
+	return -1;
+
+    memset(m->m_data, 0, m->m_size);
+
+    m->m_data += IF_MAXLINKHDR;
+    tp = (void *)m->m_data;
+    m->m_data += sizeof(struct udpiphdr);
+
+    tp->tp_op = htons(TFTP_OACK);
+    for (i = 0; i < nb; i++) {
+        n += snprintf(tp->x.tp_buf + n, sizeof(tp->x.tp_buf) - n, "%s",
+                      keys[i]) + 1;
+        n += snprintf(tp->x.tp_buf + n, sizeof(tp->x.tp_buf) - n, "%u",
+                      values[i]) + 1;
+    }
+
+    saddr.sin_addr = recv_tp->ip.ip_dst;
+    saddr.sin_port = recv_tp->udp.uh_dport;
+
+    daddr.sin_addr = spt->client_ip;
+    daddr.sin_port = spt->client_port;
+
+    m->m_len = sizeof(struct tftp_t) - 514 + n -
+        sizeof(struct ip) - sizeof(struct udphdr);
+    udp_output2(NULL, m, &saddr, &daddr, IPTOS_LOWDELAY);
+
+    return 0;
+}
+
+static void tftp_send_error(struct tftp_session *spt,
+                            uint16_t errorcode, const char *msg,
+                            struct tftp_t *recv_tp)
+{
+  struct sockaddr_in saddr, daddr;
+  struct mbuf *m;
+  struct tftp_t *tp;
+
+  m = m_get(spt->slirp);
+
+  if (!m) {
+    goto out;
+  }
+
+  memset(m->m_data, 0, m->m_size);
+
+  m->m_data += IF_MAXLINKHDR;
+  tp = (void *)m->m_data;
+  m->m_data += sizeof(struct udpiphdr);
+
+  tp->tp_op = htons(TFTP_ERROR);
+  tp->x.tp_error.tp_error_code = htons(errorcode);
+  pstrcpy((char *)tp->x.tp_error.tp_msg, sizeof(tp->x.tp_error.tp_msg), msg);
+
+  saddr.sin_addr = recv_tp->ip.ip_dst;
+  saddr.sin_port = recv_tp->udp.uh_dport;
+
+  daddr.sin_addr = spt->client_ip;
+  daddr.sin_port = spt->client_port;
+
+  m->m_len = sizeof(struct tftp_t) - 514 + 3 + strlen(msg) -
+        sizeof(struct ip) - sizeof(struct udphdr);
+
+  udp_output2(NULL, m, &saddr, &daddr, IPTOS_LOWDELAY);
+
+out:
+  tftp_session_terminate(spt);
+}
+
+static void tftp_send_next_block(struct tftp_session *spt,
+                                 struct tftp_t *recv_tp)
+{
+  struct sockaddr_in saddr, daddr;
+  struct mbuf *m;
+  struct tftp_t *tp;
+  int nobytes;
+
+  m = m_get(spt->slirp);
+
+  if (!m) {
+    return;
+  }
+
+  memset(m->m_data, 0, m->m_size);
+
+  m->m_data += IF_MAXLINKHDR;
+  tp = (void *)m->m_data;
+  m->m_data += sizeof(struct udpiphdr);
+
+  tp->tp_op = htons(TFTP_DATA);
+  tp->x.tp_data.tp_block_nr = htons((spt->block_nr + 1) & 0xffff);
+
+  saddr.sin_addr = recv_tp->ip.ip_dst;
+  saddr.sin_port = recv_tp->udp.uh_dport;
+
+  daddr.sin_addr = spt->client_ip;
+  daddr.sin_port = spt->client_port;
+
+  nobytes = tftp_read_data(spt, spt->block_nr, tp->x.tp_data.tp_buf, 512);
+
+  if (nobytes < 0) {
+    m_free(m);
+
+    /* send "file not found" error back */
+
+    tftp_send_error(spt, 1, "File not found", tp);
+
+    return;
+  }
+
+  m->m_len = sizeof(struct tftp_t) - (512 - nobytes) -
+        sizeof(struct ip) - sizeof(struct udphdr);
+
+  udp_output2(NULL, m, &saddr, &daddr, IPTOS_LOWDELAY);
+
+  if (nobytes == 512) {
+    tftp_session_update(spt);
+  }
+  else {
+    tftp_session_terminate(spt);
+  }
+
+  spt->block_nr++;
+}
+
+static void tftp_handle_rrq(Slirp *slirp, struct tftp_t *tp, int pktlen)
+{
+  struct tftp_session *spt;
+  int s, k;
+  size_t prefix_len;
+  char *req_fname;
+  const char *option_name[2];
+  uint32_t option_value[2];
+  int nb_options = 0;
+
+  /* check if a session already exists and if so terminate it */
+  s = tftp_session_find(slirp, tp);
+  if (s >= 0) {
+    tftp_session_terminate(&slirp->tftp_sessions[s]);
+  }
+
+  s = tftp_session_allocate(slirp, tp);
+
+  if (s < 0) {
+    return;
+  }
+
+  spt = &slirp->tftp_sessions[s];
+
+  /* unspecified prefix means service disabled */
+  if (!slirp->tftp_prefix) {
+      tftp_send_error(spt, 2, "Access violation", tp);
+      return;
+  }
+
+  /* skip header fields */
+  k = 0;
+  pktlen -= offsetof(struct tftp_t, x.tp_buf);
+
+  /* prepend tftp_prefix */
+  prefix_len = strlen(slirp->tftp_prefix);
+  spt->filename = g_malloc(prefix_len + TFTP_FILENAME_MAX + 2);
+  memcpy(spt->filename, slirp->tftp_prefix, prefix_len);
+  spt->filename[prefix_len] = '/';
+
+  /* get name */
+  req_fname = spt->filename + prefix_len + 1;
+
+  while (1) {
+    if (k >= TFTP_FILENAME_MAX || k >= pktlen) {
+      tftp_send_error(spt, 2, "Access violation", tp);
+      return;
+    }
+    req_fname[k] = tp->x.tp_buf[k];
+    if (req_fname[k++] == '\0') {
+      break;
+    }
+  }
+
+  /* check mode */
+  if ((pktlen - k) < 6) {
+    tftp_send_error(spt, 2, "Access violation", tp);
+    return;
+  }
+
+  if (strcasecmp(&tp->x.tp_buf[k], "octet") != 0) {
+      tftp_send_error(spt, 4, "Unsupported transfer mode", tp);
+      return;
+  }
+
+  k += 6; /* skipping octet */
+
+  /* do sanity checks on the filename */
+  if (!strncmp(req_fname, "../", 3) ||
+      req_fname[strlen(req_fname) - 1] == '/' ||
+      strstr(req_fname, "/../")) {
+      tftp_send_error(spt, 2, "Access violation", tp);
+      return;
+  }
+
+  /* check if the file exists */
+  if (tftp_read_data(spt, 0, NULL, 0) < 0) {
+      tftp_send_error(spt, 1, "File not found", tp);
+      return;
+  }
+
+  if (tp->x.tp_buf[pktlen - 1] != 0) {
+      tftp_send_error(spt, 2, "Access violation", tp);
+      return;
+  }
+
+  while (k < pktlen && nb_options < ARRAY_SIZE(option_name)) {
+      const char *key, *value;
+
+      key = &tp->x.tp_buf[k];
+      k += strlen(key) + 1;
+
+      if (k >= pktlen) {
+	  tftp_send_error(spt, 2, "Access violation", tp);
+	  return;
+      }
+
+      value = &tp->x.tp_buf[k];
+      k += strlen(value) + 1;
+
+      if (strcasecmp(key, "tsize") == 0) {
+	  int tsize = atoi(value);
+	  struct stat stat_p;
+
+	  if (tsize == 0) {
+	      if (stat(spt->filename, &stat_p) == 0)
+		  tsize = stat_p.st_size;
+	      else {
+		  tftp_send_error(spt, 1, "File not found", tp);
+		  return;
+	      }
+	  }
+
+          option_name[nb_options] = "tsize";
+          option_value[nb_options] = tsize;
+          nb_options++;
+      } else if (strcasecmp(key, "blksize") == 0) {
+          int blksize = atoi(value);
+
+          /* If blksize option is bigger than what we will
+           * emit, accept the option with our packet size.
+           * Otherwise, simply do as we didn't see the option.
+           */
+          if (blksize >= 512) {
+              option_name[nb_options] = "blksize";
+              option_value[nb_options] = 512;
+              nb_options++;
+          }
+      }
+  }
+
+  if (nb_options > 0) {
+      assert(nb_options <= ARRAY_SIZE(option_name));
+      tftp_send_oack(spt, option_name, option_value, nb_options, tp);
+      return;
+  }
+
+  spt->block_nr = 0;
+  tftp_send_next_block(spt, tp);
+}
+
+static void tftp_handle_ack(Slirp *slirp, struct tftp_t *tp, int pktlen)
+{
+  int s;
+
+  s = tftp_session_find(slirp, tp);
+
+  if (s < 0) {
+    return;
+  }
+
+  tftp_send_next_block(&slirp->tftp_sessions[s], tp);
+}
+
+static void tftp_handle_error(Slirp *slirp, struct tftp_t *tp, int pktlen)
+{
+  int s;
+
+  s = tftp_session_find(slirp, tp);
+
+  if (s < 0) {
+    return;
+  }
+
+  tftp_session_terminate(&slirp->tftp_sessions[s]);
+}
+
+void tftp_input(struct mbuf *m)
+{
+  struct tftp_t *tp = (struct tftp_t *)m->m_data;
+
+  switch(ntohs(tp->tp_op)) {
+  case TFTP_RRQ:
+    tftp_handle_rrq(m->slirp, tp, m->m_len);
+    break;
+
+  case TFTP_ACK:
+    tftp_handle_ack(m->slirp, tp, m->m_len);
+    break;
+
+  case TFTP_ERROR:
+    tftp_handle_error(m->slirp, tp, m->m_len);
+    break;
+  }
+}
diff --git a/src/slirp/tftp.h b/src/slirp/tftp.h
new file mode 100644
index 0000000..e1cc24b
--- /dev/null
+++ b/src/slirp/tftp.h
@@ -0,0 +1,49 @@
+/* tftp defines */
+#ifndef SLIRP_TFTP_H
+#define SLIRP_TFTP_H 1
+
+#define TFTP_SESSIONS_MAX 20
+
+#define TFTP_SERVER	69
+
+#define TFTP_RRQ    1
+#define TFTP_WRQ    2
+#define TFTP_DATA   3
+#define TFTP_ACK    4
+#define TFTP_ERROR  5
+#define TFTP_OACK   6
+
+#define TFTP_FILENAME_MAX 512
+
+struct tftp_t {
+  struct ip ip;
+  struct udphdr udp;
+  uint16_t tp_op;
+  union {
+    struct {
+      uint16_t tp_block_nr;
+      uint8_t tp_buf[512];
+    } tp_data;
+    struct {
+      uint16_t tp_error_code;
+      uint8_t tp_msg[512];
+    } tp_error;
+    char tp_buf[512 + 2];
+  } x;
+};
+
+struct tftp_session {
+    Slirp *slirp;
+    char *filename;
+    int fd;
+
+    struct in_addr client_ip;
+    uint16_t client_port;
+    uint32_t block_nr;
+
+    int timestamp;
+};
+
+void tftp_input(struct mbuf *m);
+
+#endif
diff --git a/src/slirp/udp.c b/src/slirp/udp.c
new file mode 100644
index 0000000..fee13b4
--- /dev/null
+++ b/src/slirp/udp.c
@@ -0,0 +1,394 @@
+/*
+ * Copyright (c) 1982, 1986, 1988, 1990, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)udp_usrreq.c	8.4 (Berkeley) 1/21/94
+ * udp_usrreq.c,v 1.4 1994/10/02 17:48:45 phk Exp
+ */
+
+/*
+ * Changes and additions relating to SLiRP
+ * Copyright (c) 1995 Danny Gasparovski.
+ *
+ * Please read the file COPYRIGHT for the
+ * terms and conditions of the copyright.
+ */
+
+#include <slirp.h>
+#include "ip_icmp.h"
+
+static uint8_t udp_tos(struct socket *so);
+
+void
+udp_init(Slirp *slirp)
+{
+    slirp->udb.so_next = slirp->udb.so_prev = &slirp->udb;
+    slirp->udp_last_so = &slirp->udb;
+}
+
+void udp_cleanup(Slirp *slirp)
+{
+    while (slirp->udb.so_next != &slirp->udb) {
+        udp_detach(slirp->udb.so_next);
+    }
+}
+
+/* m->m_data  points at ip packet header
+ * m->m_len   length ip packet
+ * ip->ip_len length data (IPDU)
+ */
+void
+udp_input(register struct mbuf *m, int iphlen)
+{
+	Slirp *slirp = m->slirp;
+	register struct ip *ip;
+	register struct udphdr *uh;
+	int len;
+	struct ip save_ip;
+	struct socket *so;
+
+	DEBUG_CALL("udp_input");
+	DEBUG_ARG("m = %p", m);
+	DEBUG_ARG("iphlen = %d", iphlen);
+
+	/*
+	 * Strip IP options, if any; should skip this,
+	 * make available to user, and use on returned packets,
+	 * but we don't yet have a way to check the checksum
+	 * with options still present.
+	 */
+	if(iphlen > sizeof(struct ip)) {
+		ip_stripoptions(m, (struct mbuf *)0);
+		iphlen = sizeof(struct ip);
+	}
+
+	/*
+	 * Get IP and UDP header together in first mbuf.
+	 */
+	ip = mtod(m, struct ip *);
+	uh = (struct udphdr *)((caddr_t)ip + iphlen);
+
+	/*
+	 * Make mbuf data length reflect UDP length.
+	 * If not enough data to reflect UDP length, drop.
+	 */
+	len = ntohs((uint16_t)uh->uh_ulen);
+
+	if (ip->ip_len != len) {
+		if (len > ip->ip_len) {
+			goto bad;
+		}
+		m_adj(m, len - ip->ip_len);
+		ip->ip_len = len;
+	}
+
+	/*
+	 * Save a copy of the IP header in case we want restore it
+	 * for sending an ICMP error message in response.
+	 */
+	save_ip = *ip;
+	save_ip.ip_len+= iphlen;         /* tcp_input subtracts this */
+
+	/*
+	 * Checksum extended UDP header and data.
+	 */
+	if (uh->uh_sum) {
+      memset(&((struct ipovly *)ip)->ih_mbuf, 0, sizeof(struct mbuf_ptr));
+	  ((struct ipovly *)ip)->ih_x1 = 0;
+	  ((struct ipovly *)ip)->ih_len = uh->uh_ulen;
+	  if(cksum(m, len + sizeof(struct ip))) {
+	    goto bad;
+	  }
+	}
+
+        /*
+         *  handle DHCP/BOOTP
+         */
+        if (ntohs(uh->uh_dport) == BOOTP_SERVER &&
+            (ip->ip_dst.s_addr == slirp->vhost_addr.s_addr ||
+             ip->ip_dst.s_addr == 0xffffffff)) {
+                bootp_input(m);
+                goto bad;
+            }
+
+        /*
+         *  handle TFTP
+         */
+        if (ntohs(uh->uh_dport) == TFTP_SERVER &&
+            ip->ip_dst.s_addr == slirp->vhost_addr.s_addr) {
+            tftp_input(m);
+            goto bad;
+        }
+
+        if (slirp->restricted) {
+            goto bad;
+        }
+
+	/*
+	 * Locate pcb for datagram.
+	 */
+	so = slirp->udp_last_so;
+	if (so == &slirp->udb || so->so_lport != uh->uh_sport ||
+	    so->so_laddr.s_addr != ip->ip_src.s_addr) {
+		struct socket *tmp;
+
+		for (tmp = slirp->udb.so_next; tmp != &slirp->udb;
+		     tmp = tmp->so_next) {
+			if (tmp->so_lport == uh->uh_sport &&
+			    tmp->so_laddr.s_addr == ip->ip_src.s_addr) {
+				so = tmp;
+				break;
+			}
+		}
+		if (tmp == &slirp->udb) {
+		  so = NULL;
+		} else {
+		  slirp->udp_last_so = so;
+		}
+	}
+
+	if (so == NULL) {
+	  /*
+	   * If there's no socket for this packet,
+	   * create one
+	   */
+	  so = socreate(slirp);
+	  if (!so) {
+	      goto bad;
+	  }
+	  if(udp_attach(so) == -1) {
+	    DEBUG_MISC((dfd," udp_attach errno = %d-%s\n",
+			errno,strerror(errno)));
+	    sofree(so);
+	    goto bad;
+	  }
+
+	  /*
+	   * Setup fields
+	   */
+	  so->so_laddr = ip->ip_src;
+	  so->so_lport = uh->uh_sport;
+
+	  if ((so->so_iptos = udp_tos(so)) == 0)
+	    so->so_iptos = ip->ip_tos;
+
+	  /*
+	   * XXXXX Here, check if it's in udpexec_list,
+	   * and if it is, do the fork_exec() etc.
+	   */
+	}
+
+        so->so_faddr = ip->ip_dst; /* XXX */
+        so->so_fport = uh->uh_dport; /* XXX */
+
+	iphlen += sizeof(struct udphdr);
+	m->m_len -= iphlen;
+	m->m_data += iphlen;
+
+	/*
+	 * Now we sendto() the packet.
+	 */
+	if(sosendto(so,m) == -1) {
+	  m->m_len += iphlen;
+	  m->m_data -= iphlen;
+	  *ip=save_ip;
+	  DEBUG_MISC((dfd,"udp tx errno = %d-%s\n",errno,strerror(errno)));
+	  icmp_error(m, ICMP_UNREACH,ICMP_UNREACH_NET, 0,strerror(errno));
+	}
+
+	m_free(so->so_m);   /* used for ICMP if error on sorecvfrom */
+
+	/* restore the orig mbuf packet */
+	m->m_len += iphlen;
+	m->m_data -= iphlen;
+	*ip=save_ip;
+	so->so_m=m;         /* ICMP backup */
+
+	return;
+bad:
+	m_free(m);
+}
+
+int udp_output2(struct socket *so, struct mbuf *m,
+                struct sockaddr_in *saddr, struct sockaddr_in *daddr,
+                int iptos)
+{
+	register struct udpiphdr *ui;
+	int error = 0;
+
+	DEBUG_CALL("udp_output");
+	DEBUG_ARG("so = %p", so);
+	DEBUG_ARG("m = %p", m);
+	DEBUG_ARG("saddr = %lx", (long)saddr->sin_addr.s_addr);
+	DEBUG_ARG("daddr = %lx", (long)daddr->sin_addr.s_addr);
+
+	/*
+	 * Adjust for header
+	 */
+	m->m_data -= sizeof(struct udpiphdr);
+	m->m_len += sizeof(struct udpiphdr);
+
+	/*
+	 * Fill in mbuf with extended UDP header
+	 * and addresses and length put into network format.
+	 */
+	ui = mtod(m, struct udpiphdr *);
+    memset(&ui->ui_i.ih_mbuf, 0 , sizeof(struct mbuf_ptr));
+	ui->ui_x1 = 0;
+	ui->ui_pr = IPPROTO_UDP;
+	ui->ui_len = htons(m->m_len - sizeof(struct ip));
+	/* XXXXX Check for from-one-location sockets, or from-any-location sockets */
+        ui->ui_src = saddr->sin_addr;
+	ui->ui_dst = daddr->sin_addr;
+	ui->ui_sport = saddr->sin_port;
+	ui->ui_dport = daddr->sin_port;
+	ui->ui_ulen = ui->ui_len;
+
+	/*
+	 * Stuff checksum and output datagram.
+	 */
+	ui->ui_sum = 0;
+	if ((ui->ui_sum = cksum(m, m->m_len)) == 0)
+		ui->ui_sum = 0xffff;
+	((struct ip *)ui)->ip_len = m->m_len;
+
+	((struct ip *)ui)->ip_ttl = IPDEFTTL;
+	((struct ip *)ui)->ip_tos = iptos;
+
+	error = ip_output(so, m);
+
+	return (error);
+}
+
+int udp_output(struct socket *so, struct mbuf *m,
+               struct sockaddr_in *addr)
+
+{
+    Slirp *slirp = so->slirp;
+    struct sockaddr_in saddr, daddr;
+
+    saddr = *addr;
+    if ((so->so_faddr.s_addr & slirp->vnetwork_mask.s_addr) ==
+        slirp->vnetwork_addr.s_addr) {
+        uint32_t inv_mask = ~slirp->vnetwork_mask.s_addr;
+
+        if ((so->so_faddr.s_addr & inv_mask) == inv_mask) {
+            saddr.sin_addr = slirp->vhost_addr;
+        } else if (addr->sin_addr.s_addr == loopback_addr.s_addr ||
+                   so->so_faddr.s_addr != slirp->vhost_addr.s_addr) {
+            saddr.sin_addr = so->so_faddr;
+        }
+    }
+    daddr.sin_addr = so->so_laddr;
+    daddr.sin_port = so->so_lport;
+
+    return udp_output2(so, m, &saddr, &daddr, so->so_iptos);
+}
+
+int
+udp_attach(struct socket *so)
+{
+  if((so->s = qemu_socket(AF_INET,SOCK_DGRAM,0)) != -1) {
+    so->so_expire = curtime + SO_EXPIRE;
+    insque(so, &so->slirp->udb);
+  }
+  return(so->s);
+}
+
+void
+udp_detach(struct socket *so)
+{
+	closesocket(so->s);
+	sofree(so);
+}
+
+static const struct tos_t udptos[] = {
+	{0, 53, IPTOS_LOWDELAY, 0},			/* DNS */
+	{0, 0, 0, 0}
+};
+
+static uint8_t
+udp_tos(struct socket *so)
+{
+	int i = 0;
+
+	while(udptos[i].tos) {
+		if ((udptos[i].fport && ntohs(so->so_fport) == udptos[i].fport) ||
+		    (udptos[i].lport && ntohs(so->so_lport) == udptos[i].lport)) {
+		    	so->so_emu = udptos[i].emu;
+			return udptos[i].tos;
+		}
+		i++;
+	}
+
+	return 0;
+}
+
+struct socket *
+udp_listen(Slirp *slirp, uint32_t haddr, u_int hport, uint32_t laddr,
+           u_int lport, int flags)
+{
+	struct sockaddr_in addr;
+	struct socket *so;
+	socklen_t addrlen = sizeof(struct sockaddr_in);
+
+	so = socreate(slirp);
+	if (!so) {
+	    return NULL;
+	}
+	so->s = qemu_socket(AF_INET,SOCK_DGRAM,0);
+	so->so_expire = curtime + SO_EXPIRE;
+	insque(so, &slirp->udb);
+
+	addr.sin_family = AF_INET;
+	addr.sin_addr.s_addr = haddr;
+	addr.sin_port = hport;
+
+	if (bind(so->s,(struct sockaddr *)&addr, addrlen) < 0) {
+		udp_detach(so);
+		return NULL;
+	}
+	socket_set_fast_reuse(so->s);
+
+	getsockname(so->s,(struct sockaddr *)&addr,&addrlen);
+	so->so_fport = addr.sin_port;
+	if (addr.sin_addr.s_addr == 0 ||
+	    addr.sin_addr.s_addr == loopback_addr.s_addr) {
+	   so->so_faddr = slirp->vhost_addr;
+	} else {
+	   so->so_faddr = addr.sin_addr;
+	}
+	so->so_lport = lport;
+	so->so_laddr.s_addr = laddr;
+	if (flags != SS_FACCEPTONCE)
+	   so->so_expire = 0;
+
+	so->so_state &= SS_PERSISTENT_MASK;
+	so->so_state |= SS_ISFCONNECTED | flags;
+
+	return so;
+}
diff --git a/src/slirp/udp.h b/src/slirp/udp.h
new file mode 100644
index 0000000..9bf31fe
--- /dev/null
+++ b/src/slirp/udp.h
@@ -0,0 +1,87 @@
+/*
+ * Copyright (c) 1982, 1986, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)udp.h	8.1 (Berkeley) 6/10/93
+ * udp.h,v 1.3 1994/08/21 05:27:41 paul Exp
+ */
+
+#ifndef _UDP_H_
+#define _UDP_H_
+
+#define UDP_TTL 0x60
+#define UDP_UDPDATALEN 16192
+
+/*
+ * Udp protocol header.
+ * Per RFC 768, September, 1981.
+ */
+struct udphdr {
+    uint16_t uh_sport;          /* source port */
+    uint16_t uh_dport;          /* destination port */
+    int16_t  uh_ulen;           /* udp length */
+    uint16_t uh_sum;            /* udp checksum */
+};
+
+/*
+ * UDP kernel structures and variables.
+ */
+struct udpiphdr {
+	        struct  ipovly ui_i;            /* overlaid ip structure */
+	        struct  udphdr ui_u;            /* udp header */
+};
+#define ui_mbuf         ui_i.ih_mbuf.mptr
+#define ui_x1           ui_i.ih_x1
+#define ui_pr           ui_i.ih_pr
+#define ui_len          ui_i.ih_len
+#define ui_src          ui_i.ih_src
+#define ui_dst          ui_i.ih_dst
+#define ui_sport        ui_u.uh_sport
+#define ui_dport        ui_u.uh_dport
+#define ui_ulen         ui_u.uh_ulen
+#define ui_sum          ui_u.uh_sum
+
+/*
+ * Names for UDP sysctl objects
+ */
+#define UDPCTL_CHECKSUM         1       /* checksum UDP packets */
+#define UDPCTL_MAXID            2
+
+struct mbuf;
+
+void udp_init(Slirp *);
+void udp_cleanup(Slirp *);
+void udp_input(register struct mbuf *, int);
+int udp_output(struct socket *, struct mbuf *, struct sockaddr_in *);
+int udp_attach(struct socket *);
+void udp_detach(struct socket *);
+struct socket * udp_listen(Slirp *, uint32_t, u_int, uint32_t, u_int,
+                           int);
+int udp_output2(struct socket *so, struct mbuf *m,
+                struct sockaddr_in *saddr, struct sockaddr_in *daddr,
+                int iptos);
+#endif