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-rw-r--r--sys/netinet/ip_input.c1833
1 files changed, 1833 insertions, 0 deletions
diff --git a/sys/netinet/ip_input.c b/sys/netinet/ip_input.c
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+++ b/sys/netinet/ip_input.c
@@ -0,0 +1,1833 @@
+/*
+ * 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. All advertising materials mentioning features or use of this software
+ * must display the following acknowledgement:
+ * This product includes software developed by the University of
+ * California, Berkeley and its contributors.
+ * 4. 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
+ * $FreeBSD$
+ */
+
+#define _IP_VHL
+
+#include "opt_bootp.h"
+#include "opt_ipfw.h"
+#include "opt_ipdn.h"
+#include "opt_ipdivert.h"
+#include "opt_ipfilter.h"
+#include "opt_ipstealth.h"
+#include "opt_ipsec.h"
+#include "opt_pfil_hooks.h"
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/mbuf.h>
+#include <sys/malloc.h>
+#include <sys/domain.h>
+#include <sys/protosw.h>
+#include <sys/socket.h>
+#include <sys/time.h>
+#include <sys/kernel.h>
+#include <sys/syslog.h>
+#include <sys/sysctl.h>
+
+#include <net/pfil.h>
+#include <net/if.h>
+#include <net/if_var.h>
+#include <net/if_dl.h>
+#include <net/route.h>
+#include <net/netisr.h>
+#include <net/intrq.h>
+
+#include <netinet/in.h>
+#include <netinet/in_systm.h>
+#include <netinet/in_var.h>
+#include <netinet/ip.h>
+#include <netinet/in_pcb.h>
+#include <netinet/ip_var.h>
+#include <netinet/ip_icmp.h>
+#include <machine/in_cksum.h>
+
+#include <netinet/ipprotosw.h>
+
+#include <sys/socketvar.h>
+
+#include <netinet/ip_fw.h>
+
+#ifdef IPSEC
+#include <netinet6/ipsec.h>
+#include <netkey/key.h>
+#endif
+
+#include "faith.h"
+#if defined(NFAITH) && NFAITH > 0
+#include <net/if_types.h>
+#endif
+
+#ifdef DUMMYNET
+#include <netinet/ip_dummynet.h>
+#endif
+
+int rsvp_on = 0;
+static int ip_rsvp_on;
+struct socket *ip_rsvpd;
+
+int ipforwarding = 0;
+SYSCTL_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_RW,
+ &ipforwarding, 0, "Enable IP forwarding between interfaces");
+
+static int ipsendredirects = 1; /* XXX */
+SYSCTL_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_RW,
+ &ipsendredirects, 0, "Enable sending IP redirects");
+
+int ip_defttl = IPDEFTTL;
+SYSCTL_INT(_net_inet_ip, IPCTL_DEFTTL, ttl, CTLFLAG_RW,
+ &ip_defttl, 0, "Maximum TTL on IP packets");
+
+static int ip_dosourceroute = 0;
+SYSCTL_INT(_net_inet_ip, IPCTL_SOURCEROUTE, sourceroute, CTLFLAG_RW,
+ &ip_dosourceroute, 0, "Enable forwarding source routed IP packets");
+
+static int ip_acceptsourceroute = 0;
+SYSCTL_INT(_net_inet_ip, IPCTL_ACCEPTSOURCEROUTE, accept_sourceroute,
+ CTLFLAG_RW, &ip_acceptsourceroute, 0,
+ "Enable accepting source routed IP packets");
+
+static int ip_keepfaith = 0;
+SYSCTL_INT(_net_inet_ip, IPCTL_KEEPFAITH, keepfaith, CTLFLAG_RW,
+ &ip_keepfaith, 0,
+ "Enable packet capture for FAITH IPv4->IPv6 translater daemon");
+
+/*
+ * XXX - Setting ip_checkinterface mostly implements the receive side of
+ * the Strong ES model described in RFC 1122, but since the routing table
+ * and transmit implementation do not implement the Strong ES model,
+ * setting this to 1 results in an odd hybrid.
+ *
+ * XXX - ip_checkinterface currently must be disabled if you use ipnat
+ * to translate the destination address to another local interface.
+ *
+ * XXX - ip_checkinterface must be disabled if you add IP aliases
+ * to the loopback interface instead of the interface where the
+ * packets for those addresses are received.
+ */
+static int ip_checkinterface = 1;
+SYSCTL_INT(_net_inet_ip, OID_AUTO, check_interface, CTLFLAG_RW,
+ &ip_checkinterface, 0, "Verify packet arrives on correct interface");
+
+#ifdef DIAGNOSTIC
+static int ipprintfs = 0;
+#endif
+
+extern struct domain inetdomain;
+extern struct ipprotosw inetsw[];
+u_char ip_protox[IPPROTO_MAX];
+static int ipqmaxlen = IFQ_MAXLEN;
+struct in_ifaddrhead in_ifaddrhead; /* first inet address */
+SYSCTL_INT(_net_inet_ip, IPCTL_INTRQMAXLEN, intr_queue_maxlen, CTLFLAG_RW,
+ &ipintrq.ifq_maxlen, 0, "Maximum size of the IP input queue");
+SYSCTL_INT(_net_inet_ip, IPCTL_INTRQDROPS, intr_queue_drops, CTLFLAG_RD,
+ &ipintrq.ifq_drops, 0, "Number of packets dropped from the IP input queue");
+
+struct ipstat ipstat;
+SYSCTL_STRUCT(_net_inet_ip, IPCTL_STATS, stats, CTLFLAG_RD,
+ &ipstat, ipstat, "IP statistics (struct ipstat, netinet/ip_var.h)");
+
+/* Packet reassembly stuff */
+#define IPREASS_NHASH_LOG2 6
+#define IPREASS_NHASH (1 << IPREASS_NHASH_LOG2)
+#define IPREASS_HMASK (IPREASS_NHASH - 1)
+#define IPREASS_HASH(x,y) \
+ (((((x) & 0xF) | ((((x) >> 8) & 0xF) << 4)) ^ (y)) & IPREASS_HMASK)
+
+static TAILQ_HEAD(ipqhead, ipq) ipq[IPREASS_NHASH];
+static int nipq = 0; /* total # of reass queues */
+static int maxnipq;
+const int ipintrq_present = 1;
+
+#ifdef IPCTL_DEFMTU
+SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW,
+ &ip_mtu, 0, "Default MTU");
+#endif
+
+#ifdef IPSTEALTH
+static int ipstealth = 0;
+SYSCTL_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW,
+ &ipstealth, 0, "");
+#endif
+
+
+/* Firewall hooks */
+ip_fw_chk_t *ip_fw_chk_ptr;
+ip_fw_ctl_t *ip_fw_ctl_ptr;
+int fw_enable = 1 ;
+
+#ifdef DUMMYNET
+ip_dn_ctl_t *ip_dn_ctl_ptr;
+#endif
+
+
+/*
+ * We need to save the IP options in case a protocol wants to respond
+ * to an incoming packet over the same route if the packet got here
+ * using IP source routing. This allows connection establishment and
+ * maintenance when the remote end is on a network that is not known
+ * to us.
+ */
+static int ip_nhops = 0;
+static struct ip_srcrt {
+ struct in_addr dst; /* final destination */
+ char nop; /* one NOP to align */
+ char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */
+ struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)];
+} ip_srcrt;
+
+struct sockaddr_in *ip_fw_fwd_addr;
+
+static void save_rte __P((u_char *, struct in_addr));
+static int ip_dooptions __P((struct mbuf *));
+static void ip_forward __P((struct mbuf *, int));
+static void ip_freef __P((struct ipqhead *, struct ipq *));
+#ifdef IPDIVERT
+static struct mbuf *ip_reass __P((struct mbuf *, struct ipqhead *, struct ipq *, u_int32_t *, u_int16_t *));
+#else
+static struct mbuf *ip_reass __P((struct mbuf *, struct ipqhead *, struct ipq *));
+#endif
+static struct in_ifaddr *ip_rtaddr __P((struct in_addr));
+static void ipintr __P((void));
+
+/*
+ * IP initialization: fill in IP protocol switch table.
+ * All protocols not implemented in kernel go to raw IP protocol handler.
+ */
+void
+ip_init()
+{
+ register struct ipprotosw *pr;
+ register int i;
+
+ TAILQ_INIT(&in_ifaddrhead);
+ pr = (struct ipprotosw *)pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
+ if (pr == 0)
+ panic("ip_init");
+ for (i = 0; i < IPPROTO_MAX; i++)
+ ip_protox[i] = pr - inetsw;
+ for (pr = (struct ipprotosw *)inetdomain.dom_protosw;
+ pr < (struct ipprotosw *)inetdomain.dom_protoswNPROTOSW; pr++)
+ if (pr->pr_domain->dom_family == PF_INET &&
+ pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW)
+ ip_protox[pr->pr_protocol] = pr - inetsw;
+
+ for (i = 0; i < IPREASS_NHASH; i++)
+ TAILQ_INIT(&ipq[i]);
+
+ maxnipq = nmbclusters/4;
+
+ ip_id = time_second & 0xffff;
+ ipintrq.ifq_maxlen = ipqmaxlen;
+ mtx_init(&ipintrq.ifq_mtx, "ip_inq", MTX_DEF);
+
+ register_netisr(NETISR_IP, ipintr);
+}
+
+static struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET };
+struct route ipforward_rt;
+
+/*
+ * 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)
+{
+ struct ip *ip;
+ struct ipq *fp;
+ struct in_ifaddr *ia = NULL;
+ int i, hlen, checkif;
+ u_short sum;
+ u_int16_t divert_cookie; /* firewall cookie */
+ struct in_addr pkt_dst;
+#ifdef IPDIVERT
+ u_int32_t divert_info = 0; /* packet divert/tee info */
+#endif
+ struct ip_fw_chain *rule = NULL;
+#ifdef PFIL_HOOKS
+ struct packet_filter_hook *pfh;
+ struct mbuf *m0;
+ int rv;
+#endif /* PFIL_HOOKS */
+
+#ifdef IPDIVERT
+ /* Get and reset firewall cookie */
+ divert_cookie = ip_divert_cookie;
+ ip_divert_cookie = 0;
+#else
+ divert_cookie = 0;
+#endif
+
+#if defined(IPFIREWALL) && defined(DUMMYNET)
+ /*
+ * dummynet packet are prepended a vestigial mbuf with
+ * m_type = MT_DUMMYNET and m_data pointing to the matching
+ * rule.
+ */
+ if (m->m_type == MT_DUMMYNET) {
+ rule = (struct ip_fw_chain *)(m->m_data) ;
+ m = m->m_next ;
+ ip = mtod(m, struct ip *);
+ hlen = IP_VHL_HL(ip->ip_vhl) << 2;
+ goto iphack ;
+ } else
+ rule = NULL ;
+#endif
+
+#ifdef DIAGNOSTIC
+ if (m == NULL || (m->m_flags & M_PKTHDR) == 0)
+ panic("ip_input no HDR");
+#endif
+ ipstat.ips_total++;
+
+ if (m->m_pkthdr.len < sizeof(struct ip))
+ goto tooshort;
+
+ if (m->m_len < sizeof (struct ip) &&
+ (m = m_pullup(m, sizeof (struct ip))) == 0) {
+ ipstat.ips_toosmall++;
+ return;
+ }
+ ip = mtod(m, struct ip *);
+
+ if (IP_VHL_V(ip->ip_vhl) != IPVERSION) {
+ ipstat.ips_badvers++;
+ goto bad;
+ }
+
+ hlen = IP_VHL_HL(ip->ip_vhl) << 2;
+ if (hlen < sizeof(struct ip)) { /* minimum header length */
+ ipstat.ips_badhlen++;
+ goto bad;
+ }
+ if (hlen > m->m_len) {
+ if ((m = m_pullup(m, hlen)) == 0) {
+ ipstat.ips_badhlen++;
+ return;
+ }
+ ip = mtod(m, struct ip *);
+ }
+ if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) {
+ sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID);
+ } else {
+ if (hlen == sizeof(struct ip)) {
+ sum = in_cksum_hdr(ip);
+ } else {
+ sum = in_cksum(m, hlen);
+ }
+ }
+ if (sum) {
+ ipstat.ips_badsum++;
+ goto bad;
+ }
+
+ /*
+ * Convert fields to host representation.
+ */
+ NTOHS(ip->ip_len);
+ if (ip->ip_len < hlen) {
+ ipstat.ips_badlen++;
+ goto bad;
+ }
+ 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_pkthdr.len < ip->ip_len) {
+tooshort:
+ ipstat.ips_tooshort++;
+ goto bad;
+ }
+ if (m->m_pkthdr.len > ip->ip_len) {
+ if (m->m_len == m->m_pkthdr.len) {
+ m->m_len = ip->ip_len;
+ m->m_pkthdr.len = ip->ip_len;
+ } else
+ m_adj(m, ip->ip_len - m->m_pkthdr.len);
+ }
+
+ /*
+ * Don't accept packets with a loopback destination address
+ * unless they arrived via the loopback interface.
+ */
+ if ((ntohl(ip->ip_dst.s_addr) & IN_CLASSA_NET) ==
+ (IN_LOOPBACKNET << IN_CLASSA_NSHIFT) &&
+ (m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) {
+ goto bad;
+ }
+
+ /*
+ * IpHack's section.
+ * Right now when no processing on packet has done
+ * and it is still fresh out of network we do our black
+ * deals with it.
+ * - Firewall: deny/allow/divert
+ * - Xlate: translate packet's addr/port (NAT).
+ * - Pipe: pass pkt through dummynet.
+ * - Wrap: fake packet's addr/port <unimpl.>
+ * - Encapsulate: put it in another IP and send out. <unimp.>
+ */
+
+#if defined(IPFIREWALL) && defined(DUMMYNET)
+iphack:
+#endif
+
+#ifdef PFIL_HOOKS
+ /*
+ * Run through list of hooks for input packets. If there are any
+ * filters which require that additional packets in the flow are
+ * not fast-forwarded, they must clear the M_CANFASTFWD flag.
+ * Note that filters must _never_ set this flag, as another filter
+ * in the list may have previously cleared it.
+ */
+ m0 = m;
+ pfh = pfil_hook_get(PFIL_IN, &inetsw[ip_protox[IPPROTO_IP]].pr_pfh);
+ for (; pfh; pfh = TAILQ_NEXT(pfh, pfil_link))
+ if (pfh->pfil_func) {
+ rv = pfh->pfil_func(ip, hlen,
+ m->m_pkthdr.rcvif, 0, &m0);
+ if (rv)
+ return;
+ m = m0;
+ if (m == NULL)
+ return;
+ ip = mtod(m, struct ip *);
+ }
+#endif /* PFIL_HOOKS */
+
+ if (fw_enable && ip_fw_chk_ptr) {
+#ifdef IPFIREWALL_FORWARD
+ /*
+ * If we've been forwarded from the output side, then
+ * skip the firewall a second time
+ */
+ if (ip_fw_fwd_addr)
+ goto ours;
+#endif /* IPFIREWALL_FORWARD */
+ /*
+ * See the comment in ip_output for the return values
+ * produced by the firewall.
+ */
+ i = (*ip_fw_chk_ptr)(&ip,
+ hlen, NULL, &divert_cookie, &m, &rule, &ip_fw_fwd_addr);
+ if (i & IP_FW_PORT_DENY_FLAG) { /* XXX new interface-denied */
+ if (m)
+ m_freem(m);
+ return ;
+ }
+ if (m == NULL) { /* Packet discarded by firewall */
+ static int __debug=10;
+ if (__debug >0) {
+ printf("firewall returns NULL, please update!\n");
+ __debug-- ;
+ }
+ return;
+ }
+ if (i == 0 && ip_fw_fwd_addr == NULL) /* common case */
+ goto pass;
+#ifdef DUMMYNET
+ if ((i & IP_FW_PORT_DYNT_FLAG) != 0) {
+ /* Send packet to the appropriate pipe */
+ dummynet_io(i&0xffff,DN_TO_IP_IN,m,NULL,NULL,0, rule,
+ 0);
+ return;
+ }
+#endif
+#ifdef IPDIVERT
+ if (i != 0 && (i & IP_FW_PORT_DYNT_FLAG) == 0) {
+ /* Divert or tee packet */
+ divert_info = i;
+ goto ours;
+ }
+#endif
+#ifdef IPFIREWALL_FORWARD
+ if (i == 0 && ip_fw_fwd_addr != NULL)
+ goto pass;
+#endif
+ /*
+ * if we get here, the packet must be dropped
+ */
+ m_freem(m);
+ return;
+ }
+pass:
+
+ /*
+ * Process options and, if not destined for us,
+ * ship it on. ip_dooptions returns 1 when an
+ * error was detected (causing an icmp message
+ * to be sent and the original packet to be freed).
+ */
+ ip_nhops = 0; /* for source routed packets */
+ if (hlen > sizeof (struct ip) && ip_dooptions(m)) {
+#ifdef IPFIREWALL_FORWARD
+ ip_fw_fwd_addr = NULL;
+#endif
+ return;
+ }
+
+ /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no
+ * matter if it is destined to another node, or whether it is
+ * a multicast one, RSVP wants it! and prevents it from being forwarded
+ * anywhere else. Also checks if the rsvp daemon is running before
+ * grabbing the packet.
+ */
+ if (rsvp_on && ip->ip_p==IPPROTO_RSVP)
+ goto ours;
+
+ /*
+ * Check our list of addresses, to see if the packet is for us.
+ * If we don't have any addresses, assume any unicast packet
+ * we receive might be for us (and let the upper layers deal
+ * with it).
+ */
+ if (TAILQ_EMPTY(&in_ifaddrhead) &&
+ (m->m_flags & (M_MCAST|M_BCAST)) == 0)
+ goto ours;
+
+ /*
+ * Cache the destination address of the packet; this may be
+ * changed by use of 'ipfw fwd'.
+ */
+ pkt_dst = ip_fw_fwd_addr == NULL ?
+ ip->ip_dst : ip_fw_fwd_addr->sin_addr;
+
+ /*
+ * Enable a consistency check between the destination address
+ * and the arrival interface for a unicast packet (the RFC 1122
+ * strong ES model) if IP forwarding is disabled and the packet
+ * is not locally generated and the packet is not subject to
+ * 'ipfw fwd'.
+ *
+ * XXX - Checking also should be disabled if the destination
+ * address is ipnat'ed to a different interface.
+ *
+ * XXX - Checking is incompatible with IP aliases added
+ * to the loopback interface instead of the interface where
+ * the packets are received.
+ */
+ checkif = ip_checkinterface && (ipforwarding == 0) &&
+ ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) &&
+ (ip_fw_fwd_addr == NULL);
+
+ TAILQ_FOREACH(ia, &in_ifaddrhead, ia_link) {
+#define satosin(sa) ((struct sockaddr_in *)(sa))
+
+#ifdef BOOTP_COMPAT
+ if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY)
+ goto ours;
+#endif
+ /*
+ * If the address matches, verify that the packet
+ * arrived via the correct interface if checking is
+ * enabled.
+ */
+ if (IA_SIN(ia)->sin_addr.s_addr == pkt_dst.s_addr &&
+ (!checkif || ia->ia_ifp == m->m_pkthdr.rcvif))
+ goto ours;
+ /*
+ * Only accept broadcast packets that arrive via the
+ * matching interface. Reception of forwarded directed
+ * broadcasts would be handled via ip_forward() and
+ * ether_output() with the loopback into the stack for
+ * SIMPLEX interfaces handled by ether_output().
+ */
+ if (ia->ia_ifp == m->m_pkthdr.rcvif &&
+ ia->ia_ifp && ia->ia_ifp->if_flags & IFF_BROADCAST) {
+ if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr ==
+ pkt_dst.s_addr)
+ goto ours;
+ if (ia->ia_netbroadcast.s_addr == pkt_dst.s_addr)
+ goto ours;
+ }
+ }
+ if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) {
+ struct in_multi *inm;
+ if (ip_mrouter) {
+ /*
+ * If we are acting as a multicast router, all
+ * incoming multicast packets are passed to the
+ * kernel-level multicast forwarding function.
+ * The packet is returned (relatively) intact; if
+ * ip_mforward() returns a non-zero value, the packet
+ * must be discarded, else it may be accepted below.
+ */
+ if (ip_mforward(ip, m->m_pkthdr.rcvif, m, 0) != 0) {
+ ipstat.ips_cantforward++;
+ m_freem(m);
+ return;
+ }
+
+ /*
+ * The process-level routing demon needs to receive
+ * all multicast IGMP packets, whether or not this
+ * host belongs to their destination groups.
+ */
+ if (ip->ip_p == IPPROTO_IGMP)
+ goto ours;
+ ipstat.ips_forward++;
+ }
+ /*
+ * See if we belong to the destination multicast group on the
+ * arrival interface.
+ */
+ IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm);
+ if (inm == NULL) {
+ ipstat.ips_notmember++;
+ m_freem(m);
+ return;
+ }
+ goto ours;
+ }
+ if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST)
+ goto ours;
+ if (ip->ip_dst.s_addr == INADDR_ANY)
+ goto ours;
+
+#if defined(NFAITH) && 0 < NFAITH
+ /*
+ * FAITH(Firewall Aided Internet Translator)
+ */
+ if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) {
+ if (ip_keepfaith) {
+ if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP)
+ goto ours;
+ }
+ m_freem(m);
+ return;
+ }
+#endif
+ /*
+ * Not for us; forward if possible and desirable.
+ */
+ if (ipforwarding == 0) {
+ ipstat.ips_cantforward++;
+ m_freem(m);
+ } else
+ ip_forward(m, 0);
+#ifdef IPFIREWALL_FORWARD
+ ip_fw_fwd_addr = NULL;
+#endif
+ return;
+
+ours:
+ /* Count the packet in the ip address stats */
+ if (ia != NULL) {
+ ia->ia_ifa.if_ipackets++;
+ ia->ia_ifa.if_ibytes += m->m_pkthdr.len;
+ }
+
+ /*
+ * 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.)
+ */
+ if (ip->ip_off & (IP_MF | IP_OFFMASK)) {
+
+ sum = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id);
+ /*
+ * Look for queue of fragments
+ * of this datagram.
+ */
+ TAILQ_FOREACH(fp, &ipq[sum], ipq_list)
+ 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 = 0;
+
+ /* check if there's a place for the new queue */
+ if (nipq > maxnipq) {
+ /*
+ * drop something from the tail of the current queue
+ * before proceeding further
+ */
+ struct ipq *q = TAILQ_LAST(&ipq[sum], ipqhead);
+ if (q == NULL) { /* gak */
+ for (i = 0; i < IPREASS_NHASH; i++) {
+ struct ipq *r = TAILQ_LAST(&ipq[i], ipqhead);
+ if (r) {
+ ip_freef(&ipq[i], r);
+ break;
+ }
+ }
+ } else
+ ip_freef(&ipq[sum], q);
+ }
+found:
+ /*
+ * Adjust ip_len to not reflect header,
+ * convert offset of this to bytes.
+ */
+ ip->ip_len -= hlen;
+ if (ip->ip_off & IP_MF) {
+ /*
+ * Make sure that fragments have a data length
+ * that's a non-zero multiple of 8 bytes.
+ */
+ if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) {
+ ipstat.ips_toosmall++; /* XXX */
+ goto bad;
+ }
+ m->m_flags |= M_FRAG;
+ }
+ ip->ip_off <<= 3;
+
+ /*
+ * Attempt reassembly; if it succeeds, proceed.
+ */
+ ipstat.ips_fragments++;
+ m->m_pkthdr.header = ip;
+#ifdef IPDIVERT
+ m = ip_reass(m,
+ &ipq[sum], fp, &divert_info, &divert_cookie);
+#else
+ m = ip_reass(m, &ipq[sum], fp);
+#endif
+ if (m == 0) {
+#ifdef IPFIREWALL_FORWARD
+ ip_fw_fwd_addr = NULL;
+#endif
+ return;
+ }
+ ipstat.ips_reassembled++;
+ ip = mtod(m, struct ip *);
+ /* Get the header length of the reassembled packet */
+ hlen = IP_VHL_HL(ip->ip_vhl) << 2;
+#ifdef IPDIVERT
+ /* Restore original checksum before diverting packet */
+ if (divert_info != 0) {
+ ip->ip_len += hlen;
+ HTONS(ip->ip_len);
+ HTONS(ip->ip_off);
+ ip->ip_sum = 0;
+ if (hlen == sizeof(struct ip))
+ ip->ip_sum = in_cksum_hdr(ip);
+ else
+ ip->ip_sum = in_cksum(m, hlen);
+ NTOHS(ip->ip_off);
+ NTOHS(ip->ip_len);
+ ip->ip_len -= hlen;
+ }
+#endif
+ } else
+ ip->ip_len -= hlen;
+
+#ifdef IPDIVERT
+ /*
+ * Divert or tee packet to the divert protocol if required.
+ *
+ * If divert_info is zero then cookie should be too, so we shouldn't
+ * need to clear them here. Assume divert_packet() does so also.
+ */
+ if (divert_info != 0) {
+ struct mbuf *clone = NULL;
+
+ /* Clone packet if we're doing a 'tee' */
+ if ((divert_info & IP_FW_PORT_TEE_FLAG) != 0)
+ clone = m_dup(m, M_DONTWAIT);
+
+ /* Restore packet header fields to original values */
+ ip->ip_len += hlen;
+ HTONS(ip->ip_len);
+ HTONS(ip->ip_off);
+
+ /* Deliver packet to divert input routine */
+ ip_divert_cookie = divert_cookie;
+ divert_packet(m, 1, divert_info & 0xffff);
+ ipstat.ips_delivered++;
+
+ /* If 'tee', continue with original packet */
+ if (clone == NULL)
+ return;
+ m = clone;
+ ip = mtod(m, struct ip *);
+ }
+#endif
+
+ /*
+ * Switch out to protocol's input routine.
+ */
+ ipstat.ips_delivered++;
+ {
+ int off = hlen, nh = ip->ip_p;
+
+ (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, off, nh);
+#ifdef IPFIREWALL_FORWARD
+ ip_fw_fwd_addr = NULL; /* tcp needed it */
+#endif
+ return;
+ }
+bad:
+#ifdef IPFIREWALL_FORWARD
+ ip_fw_fwd_addr = NULL;
+#endif
+ m_freem(m);
+}
+
+/*
+ * IP software interrupt routine - to go away sometime soon
+ */
+static void
+ipintr(void)
+{
+ struct mbuf *m;
+
+ while (1) {
+ IF_DEQUEUE(&ipintrq, m);
+ if (m == 0)
+ return;
+ ip_input(m);
+ }
+}
+
+/*
+ * 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.
+ *
+ * When IPDIVERT enabled, keep additional state with each packet that
+ * tells us if we need to divert or tee the packet we're building.
+ */
+
+static struct mbuf *
+#ifdef IPDIVERT
+ip_reass(m, head, fp, divinfo, divcookie)
+#else
+ip_reass(m, head, fp)
+#endif
+ struct mbuf *m;
+ struct ipqhead *head;
+ struct ipq *fp;
+#ifdef IPDIVERT
+ u_int32_t *divinfo;
+ u_int16_t *divcookie;
+#endif
+{
+ struct ip *ip = mtod(m, struct ip *);
+ register struct mbuf *p, *q, *nq;
+ struct mbuf *t;
+ int hlen = IP_VHL_HL(ip->ip_vhl) << 2;
+ int i, next;
+
+ /*
+ * Presence of header sizes in mbufs
+ * would confuse code below.
+ */
+ m->m_data += hlen;
+ m->m_len -= hlen;
+
+ /*
+ * If first fragment to arrive, create a reassembly queue.
+ */
+ if (fp == 0) {
+ if ((t = m_get(M_DONTWAIT, MT_FTABLE)) == NULL)
+ goto dropfrag;
+ fp = mtod(t, struct ipq *);
+ TAILQ_INSERT_HEAD(head, fp, ipq_list);
+ nipq++;
+ fp->ipq_ttl = IPFRAGTTL;
+ fp->ipq_p = ip->ip_p;
+ fp->ipq_id = ip->ip_id;
+ fp->ipq_src = ip->ip_src;
+ fp->ipq_dst = ip->ip_dst;
+ fp->ipq_frags = m;
+ m->m_nextpkt = NULL;
+#ifdef IPDIVERT
+ fp->ipq_div_info = 0;
+ fp->ipq_div_cookie = 0;
+#endif
+ goto inserted;
+ }
+
+#define GETIP(m) ((struct ip*)((m)->m_pkthdr.header))
+
+ /*
+ * Find a segment which begins after this one does.
+ */
+ for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt)
+ if (GETIP(q)->ip_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, otherwise
+ * stick new segment in the proper place.
+ *
+ * If some of the data is dropped from the the preceding
+ * segment, then it's checksum is invalidated.
+ */
+ if (p) {
+ i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off;
+ if (i > 0) {
+ if (i >= ip->ip_len)
+ goto dropfrag;
+ m_adj(m, i);
+ m->m_pkthdr.csum_flags = 0;
+ ip->ip_off += i;
+ ip->ip_len -= i;
+ }
+ m->m_nextpkt = p->m_nextpkt;
+ p->m_nextpkt = m;
+ } else {
+ m->m_nextpkt = fp->ipq_frags;
+ fp->ipq_frags = m;
+ }
+
+ /*
+ * While we overlap succeeding segments trim them or,
+ * if they are completely covered, dequeue them.
+ */
+ for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off;
+ q = nq) {
+ i = (ip->ip_off + ip->ip_len) -
+ GETIP(q)->ip_off;
+ if (i < GETIP(q)->ip_len) {
+ GETIP(q)->ip_len -= i;
+ GETIP(q)->ip_off += i;
+ m_adj(q, i);
+ q->m_pkthdr.csum_flags = 0;
+ break;
+ }
+ nq = q->m_nextpkt;
+ m->m_nextpkt = nq;
+ m_freem(q);
+ }
+
+inserted:
+
+#ifdef IPDIVERT
+ /*
+ * Transfer firewall instructions to the fragment structure.
+ * Any fragment diverting causes the whole packet to divert.
+ */
+ fp->ipq_div_info = *divinfo;
+ fp->ipq_div_cookie = *divcookie;
+ *divinfo = 0;
+ *divcookie = 0;
+#endif
+
+ /*
+ * Check for complete reassembly.
+ */
+ next = 0;
+ for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) {
+ if (GETIP(q)->ip_off != next)
+ return (0);
+ next += GETIP(q)->ip_len;
+ }
+ /* Make sure the last packet didn't have the IP_MF flag */
+ if (p->m_flags & M_FRAG)
+ return (0);
+
+ /*
+ * Reassembly is complete. Make sure the packet is a sane size.
+ */
+ q = fp->ipq_frags;
+ ip = GETIP(q);
+ if (next + (IP_VHL_HL(ip->ip_vhl) << 2) > IP_MAXPACKET) {
+ ipstat.ips_toolong++;
+ ip_freef(head, fp);
+ return (0);
+ }
+
+ /*
+ * Concatenate fragments.
+ */
+ m = q;
+ t = m->m_next;
+ m->m_next = 0;
+ m_cat(m, t);
+ nq = q->m_nextpkt;
+ q->m_nextpkt = 0;
+ for (q = nq; q != NULL; q = nq) {
+ nq = q->m_nextpkt;
+ q->m_nextpkt = NULL;
+ m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags;
+ m->m_pkthdr.csum_data += q->m_pkthdr.csum_data;
+ m_cat(m, q);
+ }
+
+#ifdef IPDIVERT
+ /*
+ * Extract firewall instructions from the fragment structure.
+ */
+ *divinfo = fp->ipq_div_info;
+ *divcookie = fp->ipq_div_cookie;
+#endif
+
+ /*
+ * Create header for new ip packet by
+ * modifying header of first packet;
+ * dequeue and discard fragment reassembly header.
+ * Make header visible.
+ */
+ ip->ip_len = next;
+ ip->ip_src = fp->ipq_src;
+ ip->ip_dst = fp->ipq_dst;
+ TAILQ_REMOVE(head, fp, ipq_list);
+ nipq--;
+ (void) m_free(dtom(fp));
+ m->m_len += (IP_VHL_HL(ip->ip_vhl) << 2);
+ m->m_data -= (IP_VHL_HL(ip->ip_vhl) << 2);
+ /* some debugging cruft by sklower, below, will go away soon */
+ if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */
+ register int plen = 0;
+ for (t = m; t; t = t->m_next)
+ plen += t->m_len;
+ m->m_pkthdr.len = plen;
+ }
+ return (m);
+
+dropfrag:
+#ifdef IPDIVERT
+ *divinfo = 0;
+ *divcookie = 0;
+#endif
+ ipstat.ips_fragdropped++;
+ m_freem(m);
+ return (0);
+
+#undef GETIP
+}
+
+/*
+ * Free a fragment reassembly header and all
+ * associated datagrams.
+ */
+static void
+ip_freef(fhp, fp)
+ struct ipqhead *fhp;
+ struct ipq *fp;
+{
+ register struct mbuf *q;
+
+ while (fp->ipq_frags) {
+ q = fp->ipq_frags;
+ fp->ipq_frags = q->m_nextpkt;
+ m_freem(q);
+ }
+ TAILQ_REMOVE(fhp, fp, ipq_list);
+ (void) m_free(dtom(fp));
+ nipq--;
+}
+
+/*
+ * IP timer processing;
+ * if a timer expires on a reassembly
+ * queue, discard it.
+ */
+void
+ip_slowtimo()
+{
+ register struct ipq *fp;
+ int s = splnet();
+ int i;
+
+ for (i = 0; i < IPREASS_NHASH; i++) {
+ for(fp = TAILQ_FIRST(&ipq[i]); fp;) {
+ struct ipq *fpp;
+
+ fpp = fp;
+ fp = TAILQ_NEXT(fp, ipq_list);
+ if(--fpp->ipq_ttl == 0) {
+ ipstat.ips_fragtimeout++;
+ ip_freef(&ipq[i], fpp);
+ }
+ }
+ }
+ ipflow_slowtimo();
+ splx(s);
+}
+
+/*
+ * Drain off all datagram fragments.
+ */
+void
+ip_drain()
+{
+ int i;
+
+ for (i = 0; i < IPREASS_NHASH; i++) {
+ while(!TAILQ_EMPTY(&ipq[i])) {
+ ipstat.ips_fragdropped++;
+ ip_freef(&ipq[i], TAILQ_FIRST(&ipq[i]));
+ }
+ }
+ in_rtqdrain();
+}
+
+/*
+ * 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.
+ */
+static 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 = ICMP_PARAMPROB, forward = 0;
+ struct in_addr *sin, dst;
+ n_time ntime;
+
+ dst = ip->ip_dst;
+ cp = (u_char *)(ip + 1);
+ cnt = (IP_VHL_HL(ip->ip_vhl) << 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 {
+ if (cnt < IPOPT_OLEN + sizeof(*cp)) {
+ code = &cp[IPOPT_OLEN] - (u_char *)ip;
+ goto bad;
+ }
+ optlen = cp[IPOPT_OLEN];
+ if (optlen < IPOPT_OLEN + sizeof(*cp) || 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;
+ }
+ if (!ip_dosourceroute)
+ goto nosourcerouting;
+ /*
+ * Loose routing, and not at next destination
+ * yet; nothing to do except forward.
+ */
+ break;
+ }
+ off--; /* 0 origin */
+ if (off > optlen - (int)sizeof(struct in_addr)) {
+ /*
+ * End of source route. Should be for us.
+ */
+ if (!ip_acceptsourceroute)
+ goto nosourcerouting;
+ save_rte(cp, ip->ip_src);
+ break;
+ }
+
+ if (!ip_dosourceroute) {
+ if (ipforwarding) {
+ char buf[16]; /* aaa.bbb.ccc.ddd\0 */
+ /*
+ * Acting as a router, so generate ICMP
+ */
+nosourcerouting:
+ strcpy(buf, inet_ntoa(ip->ip_dst));
+ log(LOG_WARNING,
+ "attempted source route from %s to %s\n",
+ inet_ntoa(ip->ip_src), buf);
+ type = ICMP_UNREACH;
+ code = ICMP_UNREACH_SRCFAIL;
+ goto bad;
+ } else {
+ /*
+ * Not acting as a router, so silently drop.
+ */
+ ipstat.ips_cantforward++;
+ m_freem(m);
+ return (1);
+ }
+ }
+
+ /*
+ * locate outgoing interface
+ */
+ (void)memcpy(&ipaddr.sin_addr, cp + off,
+ 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;
+ (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr),
+ 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 (optlen < IPOPT_OFFSET + sizeof(*cp)) {
+ code = &cp[IPOPT_OFFSET] - (u_char *)ip;
+ goto bad;
+ }
+ 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 - (int)sizeof(struct in_addr))
+ break;
+ (void)memcpy(&ipaddr.sin_addr, &ip->ip_dst,
+ 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;
+ }
+ (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr),
+ 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 - (int)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 - 1 + sizeof(n_time) +
+ sizeof(struct in_addr) > ipt->ipt_len)
+ goto bad;
+ ipaddr.sin_addr = dst;
+ ia = (INA)ifaof_ifpforaddr((SA)&ipaddr,
+ m->m_pkthdr.rcvif);
+ if (ia == 0)
+ continue;
+ (void)memcpy(sin, &IA_SIN(ia)->sin_addr,
+ sizeof(struct in_addr));
+ ipt->ipt_ptr += sizeof(struct in_addr);
+ break;
+
+ case IPOPT_TS_PRESPEC:
+ if (ipt->ipt_ptr - 1 + sizeof(n_time) +
+ sizeof(struct in_addr) > ipt->ipt_len)
+ goto bad;
+ (void)memcpy(&ipaddr.sin_addr, sin,
+ sizeof(struct in_addr));
+ if (ifa_ifwithaddr((SA)&ipaddr) == 0)
+ continue;
+ ipt->ipt_ptr += sizeof(struct in_addr);
+ break;
+
+ default:
+ goto bad;
+ }
+ ntime = iptime();
+ (void)memcpy(cp + ipt->ipt_ptr - 1, &ntime,
+ sizeof(n_time));
+ ipt->ipt_ptr += sizeof(n_time);
+ }
+ }
+ if (forward && ipforwarding) {
+ ip_forward(m, 1);
+ return (1);
+ }
+ return (0);
+bad:
+ icmp_error(m, type, code, 0, 0);
+ ipstat.ips_badoptions++;
+ return (1);
+}
+
+/*
+ * Given address of next destination (final or next hop),
+ * return internet address info of interface to be used to get there.
+ */
+static struct in_ifaddr *
+ip_rtaddr(dst)
+ struct in_addr dst;
+{
+ register struct sockaddr_in *sin;
+
+ sin = (struct sockaddr_in *) &ipforward_rt.ro_dst;
+
+ if (ipforward_rt.ro_rt == 0 ||
+ !(ipforward_rt.ro_rt->rt_flags & RTF_UP) ||
+ dst.s_addr != sin->sin_addr.s_addr) {
+ if (ipforward_rt.ro_rt) {
+ RTFREE(ipforward_rt.ro_rt);
+ ipforward_rt.ro_rt = 0;
+ }
+ sin->sin_family = AF_INET;
+ sin->sin_len = sizeof(*sin);
+ sin->sin_addr = dst;
+
+ rtalloc_ign(&ipforward_rt, RTF_PRCLONING);
+ }
+ if (ipforward_rt.ro_rt == 0)
+ return ((struct in_ifaddr *)0);
+ return ((struct in_ifaddr *) ipforward_rt.ro_rt->rt_ifa);
+}
+
+/*
+ * Save incoming source route for use in replies,
+ * to be picked up later by ip_srcroute if the receiver is interested.
+ */
+void
+save_rte(option, dst)
+ u_char *option;
+ struct in_addr dst;
+{
+ unsigned olen;
+
+ olen = option[IPOPT_OLEN];
+#ifdef DIAGNOSTIC
+ if (ipprintfs)
+ printf("save_rte: olen %d\n", olen);
+#endif
+ if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst)))
+ return;
+ bcopy(option, ip_srcrt.srcopt, olen);
+ ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr);
+ ip_srcrt.dst = dst;
+}
+
+/*
+ * Retrieve incoming source route for use in replies,
+ * in the same form used by setsockopt.
+ * The first hop is placed before the options, will be removed later.
+ */
+struct mbuf *
+ip_srcroute()
+{
+ register struct in_addr *p, *q;
+ register struct mbuf *m;
+
+ if (ip_nhops == 0)
+ return ((struct mbuf *)0);
+ m = m_get(M_DONTWAIT, MT_HEADER);
+ if (m == 0)
+ return ((struct mbuf *)0);
+
+#define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt))
+
+ /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */
+ m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) +
+ OPTSIZ;
+#ifdef DIAGNOSTIC
+ if (ipprintfs)
+ printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len);
+#endif
+
+ /*
+ * First save first hop for return route
+ */
+ p = &ip_srcrt.route[ip_nhops - 1];
+ *(mtod(m, struct in_addr *)) = *p--;
+#ifdef DIAGNOSTIC
+ if (ipprintfs)
+ printf(" hops %lx", (u_long)ntohl(mtod(m, struct in_addr *)->s_addr));
+#endif
+
+ /*
+ * Copy option fields and padding (nop) to mbuf.
+ */
+ ip_srcrt.nop = IPOPT_NOP;
+ ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF;
+ (void)memcpy(mtod(m, caddr_t) + sizeof(struct in_addr),
+ &ip_srcrt.nop, OPTSIZ);
+ q = (struct in_addr *)(mtod(m, caddr_t) +
+ sizeof(struct in_addr) + OPTSIZ);
+#undef OPTSIZ
+ /*
+ * Record return path as an IP source route,
+ * reversing the path (pointers are now aligned).
+ */
+ while (p >= ip_srcrt.route) {
+#ifdef DIAGNOSTIC
+ if (ipprintfs)
+ printf(" %lx", (u_long)ntohl(q->s_addr));
+#endif
+ *q++ = *p--;
+ }
+ /*
+ * Last hop goes to final destination.
+ */
+ *q = ip_srcrt.dst;
+#ifdef DIAGNOSTIC
+ if (ipprintfs)
+ printf(" %lx\n", (u_long)ntohl(q->s_addr));
+#endif
+ return (m);
+}
+
+/*
+ * 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(m, mopt)
+ 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_VHL_HL(ip->ip_vhl) << 2) - sizeof (struct ip);
+ opts = (caddr_t)(ip + 1);
+ i = m->m_len - (sizeof (struct ip) + olen);
+ bcopy(opts + olen, opts, (unsigned)i);
+ m->m_len -= olen;
+ if (m->m_flags & M_PKTHDR)
+ m->m_pkthdr.len -= olen;
+ ip->ip_vhl = IP_MAKE_VHL(IPVERSION, sizeof(struct ip) >> 2);
+}
+
+u_char inetctlerrmap[PRC_NCMDS] = {
+ 0, 0, 0, 0,
+ 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH,
+ EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED,
+ EMSGSIZE, EHOSTUNREACH, 0, 0,
+ 0, 0, 0, 0,
+ ENOPROTOOPT, ENETRESET
+};
+
+/*
+ * Forward a packet. If some error occurs return the sender
+ * an icmp packet. Note we can't always generate a meaningful
+ * icmp message because icmp doesn't have a large enough repertoire
+ * of codes and types.
+ *
+ * If not forwarding, just drop the packet. This could be confusing
+ * if ipforwarding was zero but some routing protocol was advancing
+ * us as a gateway to somewhere. However, we must let the routing
+ * protocol deal with that.
+ *
+ * The srcrt parameter indicates whether the packet is being forwarded
+ * via a source route.
+ */
+static void
+ip_forward(m, srcrt)
+ struct mbuf *m;
+ int srcrt;
+{
+ register struct ip *ip = mtod(m, struct ip *);
+ register struct rtentry *rt;
+ int error, type = 0, code = 0;
+ struct mbuf *mcopy;
+ n_long dest;
+ struct ifnet *destifp;
+#ifdef IPSEC
+ struct ifnet dummyifp;
+#endif
+
+ dest = 0;
+#ifdef DIAGNOSTIC
+ if (ipprintfs)
+ printf("forward: src %lx dst %lx ttl %x\n",
+ (u_long)ip->ip_src.s_addr, (u_long)ip->ip_dst.s_addr,
+ ip->ip_ttl);
+#endif
+
+
+ if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) {
+ ipstat.ips_cantforward++;
+ m_freem(m);
+ return;
+ }
+#ifdef IPSTEALTH
+ if (!ipstealth) {
+#endif
+ if (ip->ip_ttl <= IPTTLDEC) {
+ icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS,
+ dest, 0);
+ return;
+ }
+#ifdef IPSTEALTH
+ }
+#endif
+
+ if (ip_rtaddr(ip->ip_dst) == 0) {
+ icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0);
+ return;
+ } else
+ rt = ipforward_rt.ro_rt;
+
+ /*
+ * Save the IP header and at most 8 bytes of the payload,
+ * in case we need to generate an ICMP message to the src.
+ *
+ * We don't use m_copy() because it might return a reference
+ * to a shared cluster. Both this function and ip_output()
+ * assume exclusive access to the IP header in `m', so any
+ * data in a cluster may change before we reach icmp_error().
+ */
+ MGET(mcopy, M_DONTWAIT, m->m_type);
+ if (mcopy != NULL) {
+ M_COPY_PKTHDR(mcopy, m);
+ mcopy->m_len = imin((IP_VHL_HL(ip->ip_vhl) << 2) + 8,
+ (int)ip->ip_len);
+ m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t));
+ }
+
+#ifdef IPSTEALTH
+ if (!ipstealth) {
+#endif
+ ip->ip_ttl -= IPTTLDEC;
+#ifdef IPSTEALTH
+ }
+#endif
+
+ /*
+ * If forwarding packet using same interface that it came in on,
+ * perhaps should send a redirect to sender to shortcut a hop.
+ * Only send redirect if source is sending directly to us,
+ * and if packet was not source routed (or has any options).
+ * Also, don't send redirect if forwarding using a default route
+ * or a route modified by a redirect.
+ */
+#define satosin(sa) ((struct sockaddr_in *)(sa))
+ if (rt->rt_ifp == m->m_pkthdr.rcvif &&
+ (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 &&
+ satosin(rt_key(rt))->sin_addr.s_addr != 0 &&
+ ipsendredirects && !srcrt) {
+#define RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa))
+ u_long src = ntohl(ip->ip_src.s_addr);
+
+ if (RTA(rt) &&
+ (src & RTA(rt)->ia_subnetmask) == RTA(rt)->ia_subnet) {
+ if (rt->rt_flags & RTF_GATEWAY)
+ dest = satosin(rt->rt_gateway)->sin_addr.s_addr;
+ else
+ dest = ip->ip_dst.s_addr;
+ /* Router requirements says to only send host redirects */
+ type = ICMP_REDIRECT;
+ code = ICMP_REDIRECT_HOST;
+#ifdef DIAGNOSTIC
+ if (ipprintfs)
+ printf("redirect (%d) to %lx\n", code, (u_long)dest);
+#endif
+ }
+ }
+
+ error = ip_output(m, (struct mbuf *)0, &ipforward_rt,
+ IP_FORWARDING, 0);
+ if (error)
+ ipstat.ips_cantforward++;
+ else {
+ ipstat.ips_forward++;
+ if (type)
+ ipstat.ips_redirectsent++;
+ else {
+ if (mcopy) {
+ ipflow_create(&ipforward_rt, mcopy);
+ m_freem(mcopy);
+ }
+ return;
+ }
+ }
+ if (mcopy == NULL)
+ return;
+ destifp = NULL;
+
+ switch (error) {
+
+ case 0: /* forwarded, but need redirect */
+ /* type, code set above */
+ break;
+
+ case ENETUNREACH: /* shouldn't happen, checked above */
+ case EHOSTUNREACH:
+ case ENETDOWN:
+ case EHOSTDOWN:
+ default:
+ type = ICMP_UNREACH;
+ code = ICMP_UNREACH_HOST;
+ break;
+
+ case EMSGSIZE:
+ type = ICMP_UNREACH;
+ code = ICMP_UNREACH_NEEDFRAG;
+#ifndef IPSEC
+ if (ipforward_rt.ro_rt)
+ destifp = ipforward_rt.ro_rt->rt_ifp;
+#else
+ /*
+ * If the packet is routed over IPsec tunnel, tell the
+ * originator the tunnel MTU.
+ * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz
+ * XXX quickhack!!!
+ */
+ if (ipforward_rt.ro_rt) {
+ struct secpolicy *sp = NULL;
+ int ipsecerror;
+ int ipsechdr;
+ struct route *ro;
+
+ sp = ipsec4_getpolicybyaddr(mcopy,
+ IPSEC_DIR_OUTBOUND,
+ IP_FORWARDING,
+ &ipsecerror);
+
+ if (sp == NULL)
+ destifp = ipforward_rt.ro_rt->rt_ifp;
+ else {
+ /* count IPsec header size */
+ ipsechdr = ipsec4_hdrsiz(mcopy,
+ IPSEC_DIR_OUTBOUND,
+ NULL);
+
+ /*
+ * find the correct route for outer IPv4
+ * header, compute tunnel MTU.
+ *
+ * XXX BUG ALERT
+ * The "dummyifp" code relies upon the fact
+ * that icmp_error() touches only ifp->if_mtu.
+ */
+ /*XXX*/
+ destifp = NULL;
+ if (sp->req != NULL
+ && sp->req->sav != NULL
+ && sp->req->sav->sah != NULL) {
+ ro = &sp->req->sav->sah->sa_route;
+ if (ro->ro_rt && ro->ro_rt->rt_ifp) {
+ dummyifp.if_mtu =
+ ro->ro_rt->rt_ifp->if_mtu;
+ dummyifp.if_mtu -= ipsechdr;
+ destifp = &dummyifp;
+ }
+ }
+
+ key_freesp(sp);
+ }
+ }
+#endif /*IPSEC*/
+ ipstat.ips_cantfrag++;
+ break;
+
+ case ENOBUFS:
+ type = ICMP_SOURCEQUENCH;
+ code = 0;
+ break;
+
+ case EACCES: /* ipfw denied packet */
+ m_freem(mcopy);
+ return;
+ }
+ icmp_error(mcopy, type, code, dest, destifp);
+}
+
+void
+ip_savecontrol(inp, mp, ip, m)
+ register struct inpcb *inp;
+ register struct mbuf **mp;
+ register struct ip *ip;
+ register struct mbuf *m;
+{
+ if (inp->inp_socket->so_options & SO_TIMESTAMP) {
+ struct timeval tv;
+
+ microtime(&tv);
+ *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv),
+ SCM_TIMESTAMP, SOL_SOCKET);
+ if (*mp)
+ mp = &(*mp)->m_next;
+ }
+ if (inp->inp_flags & INP_RECVDSTADDR) {
+ *mp = sbcreatecontrol((caddr_t) &ip->ip_dst,
+ sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP);
+ if (*mp)
+ mp = &(*mp)->m_next;
+ }
+#ifdef notyet
+ /* XXX
+ * Moving these out of udp_input() made them even more broken
+ * than they already were.
+ */
+ /* options were tossed already */
+ if (inp->inp_flags & INP_RECVOPTS) {
+ *mp = sbcreatecontrol((caddr_t) opts_deleted_above,
+ sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP);
+ if (*mp)
+ mp = &(*mp)->m_next;
+ }
+ /* ip_srcroute doesn't do what we want here, need to fix */
+ if (inp->inp_flags & INP_RECVRETOPTS) {
+ *mp = sbcreatecontrol((caddr_t) ip_srcroute(),
+ sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP);
+ if (*mp)
+ mp = &(*mp)->m_next;
+ }
+#endif
+ if (inp->inp_flags & INP_RECVIF) {
+ struct ifnet *ifp;
+ struct sdlbuf {
+ struct sockaddr_dl sdl;
+ u_char pad[32];
+ } sdlbuf;
+ struct sockaddr_dl *sdp;
+ struct sockaddr_dl *sdl2 = &sdlbuf.sdl;
+
+ if (((ifp = m->m_pkthdr.rcvif))
+ && ( ifp->if_index && (ifp->if_index <= if_index))) {
+ sdp = (struct sockaddr_dl *)(ifnet_addrs
+ [ifp->if_index - 1]->ifa_addr);
+ /*
+ * Change our mind and don't try copy.
+ */
+ if ((sdp->sdl_family != AF_LINK)
+ || (sdp->sdl_len > sizeof(sdlbuf))) {
+ goto makedummy;
+ }
+ bcopy(sdp, sdl2, sdp->sdl_len);
+ } else {
+makedummy:
+ sdl2->sdl_len
+ = offsetof(struct sockaddr_dl, sdl_data[0]);
+ sdl2->sdl_family = AF_LINK;
+ sdl2->sdl_index = 0;
+ sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0;
+ }
+ *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len,
+ IP_RECVIF, IPPROTO_IP);
+ if (*mp)
+ mp = &(*mp)->m_next;
+ }
+}
+
+int
+ip_rsvp_init(struct socket *so)
+{
+ if (so->so_type != SOCK_RAW ||
+ so->so_proto->pr_protocol != IPPROTO_RSVP)
+ return EOPNOTSUPP;
+
+ if (ip_rsvpd != NULL)
+ return EADDRINUSE;
+
+ ip_rsvpd = so;
+ /*
+ * This may seem silly, but we need to be sure we don't over-increment
+ * the RSVP counter, in case something slips up.
+ */
+ if (!ip_rsvp_on) {
+ ip_rsvp_on = 1;
+ rsvp_on++;
+ }
+
+ return 0;
+}
+
+int
+ip_rsvp_done(void)
+{
+ ip_rsvpd = NULL;
+ /*
+ * This may seem silly, but we need to be sure we don't over-decrement
+ * the RSVP counter, in case something slips up.
+ */
+ if (ip_rsvp_on) {
+ ip_rsvp_on = 0;
+ rsvp_on--;
+ }
+ return 0;
+}
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