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-rw-r--r--ipsend/ip.c367
1 files changed, 367 insertions, 0 deletions
diff --git a/ipsend/ip.c b/ipsend/ip.c
new file mode 100644
index 0000000..e29f722
--- /dev/null
+++ b/ipsend/ip.c
@@ -0,0 +1,367 @@
+/*
+ * ip.c (C) 1995-1998 Darren Reed
+ *
+ * See the IPFILTER.LICENCE file for details on licencing.
+ */
+#if !defined(lint)
+static const char sccsid[] = "%W% %G% (C)1995";
+static const char rcsid[] = "@(#)$Id: ip.c,v 2.8.2.2 2007/02/17 12:41:51 darrenr Exp $";
+#endif
+#include <sys/param.h>
+#include <sys/types.h>
+#include <netinet/in_systm.h>
+#include <sys/socket.h>
+#ifdef __osf__
+# include "radix_ipf_local.h"
+#endif
+#include <net/if.h>
+#include <netinet/in.h>
+#include <netinet/ip.h>
+#include <sys/param.h>
+#ifndef linux
+# include <netinet/if_ether.h>
+# include <netinet/ip_var.h>
+# if __FreeBSD_version >= 300000
+# include <net/if_var.h>
+# endif
+#endif
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include "ipsend.h"
+
+
+static char *ipbuf = NULL, *ethbuf = NULL;
+
+
+u_short chksum(buf,len)
+u_short *buf;
+int len;
+{
+ u_long sum = 0;
+ int nwords = len >> 1;
+
+ for(; nwords > 0; nwords--)
+ sum += *buf++;
+ sum = (sum>>16) + (sum & 0xffff);
+ sum += (sum >>16);
+ return (~sum);
+}
+
+
+int send_ether(nfd, buf, len, gwip)
+int nfd, len;
+char *buf;
+struct in_addr gwip;
+{
+ static struct in_addr last_gw;
+ static char last_arp[6] = { 0, 0, 0, 0, 0, 0};
+ ether_header_t *eh;
+ char *s;
+ int err;
+
+ if (!ethbuf)
+ ethbuf = (char *)calloc(1, 65536+1024);
+ s = ethbuf;
+ eh = (ether_header_t *)s;
+
+ bcopy((char *)buf, s + sizeof(*eh), len);
+ if (gwip.s_addr == last_gw.s_addr)
+ {
+ bcopy(last_arp, (char *)A_A eh->ether_dhost, 6);
+ }
+ else if (arp((char *)&gwip, (char *)A_A eh->ether_dhost) == -1)
+ {
+ perror("arp");
+ return -2;
+ }
+ eh->ether_type = htons(ETHERTYPE_IP);
+ last_gw.s_addr = gwip.s_addr;
+ err = sendip(nfd, s, sizeof(*eh) + len);
+ return err;
+}
+
+
+/*
+ */
+int send_ip(nfd, mtu, ip, gwip, frag)
+int nfd, mtu;
+ip_t *ip;
+struct in_addr gwip;
+int frag;
+{
+ static struct in_addr last_gw, local_ip;
+ static char local_arp[6] = { 0, 0, 0, 0, 0, 0};
+ static char last_arp[6] = { 0, 0, 0, 0, 0, 0};
+ static u_short id = 0;
+ ether_header_t *eh;
+ ip_t ipsv;
+ int err, iplen;
+
+ if (!ipbuf)
+ {
+ ipbuf = (char *)malloc(65536);
+ if (!ipbuf)
+ {
+ perror("malloc failed");
+ return -2;
+ }
+ }
+
+ eh = (ether_header_t *)ipbuf;
+
+ bzero((char *)A_A eh->ether_shost, sizeof(eh->ether_shost));
+ if (last_gw.s_addr && (gwip.s_addr == last_gw.s_addr))
+ {
+ bcopy(last_arp, (char *)A_A eh->ether_dhost, 6);
+ }
+ else if (arp((char *)&gwip, (char *)A_A eh->ether_dhost) == -1)
+ {
+ perror("arp");
+ return -2;
+ }
+ bcopy((char *)A_A eh->ether_dhost, last_arp, sizeof(last_arp));
+ eh->ether_type = htons(ETHERTYPE_IP);
+
+ bcopy((char *)ip, (char *)&ipsv, sizeof(*ip));
+ last_gw.s_addr = gwip.s_addr;
+ iplen = ip->ip_len;
+ ip->ip_len = htons(iplen);
+ if (!(frag & 2)) {
+ if (!IP_V(ip))
+ IP_V_A(ip, IPVERSION);
+ if (!ip->ip_id)
+ ip->ip_id = htons(id++);
+ if (!ip->ip_ttl)
+ ip->ip_ttl = 60;
+ }
+
+ if (ip->ip_src.s_addr != local_ip.s_addr) {
+ (void) arp((char *)&ip->ip_src, (char *)A_A local_arp);
+ bcopy(local_arp, (char *)A_A eh->ether_shost,sizeof(last_arp));
+ local_ip = ip->ip_src;
+ } else
+ bcopy(local_arp, (char *)A_A eh->ether_shost, 6);
+
+ if (!frag || (sizeof(*eh) + iplen < mtu))
+ {
+ ip->ip_sum = 0;
+ ip->ip_sum = chksum((u_short *)ip, IP_HL(ip) << 2);
+
+ bcopy((char *)ip, ipbuf + sizeof(*eh), iplen);
+ err = sendip(nfd, ipbuf, sizeof(*eh) + iplen);
+ }
+ else
+ {
+ /*
+ * Actually, this is bogus because we're putting all IP
+ * options in every packet, which isn't always what should be
+ * done. Will do for now.
+ */
+ ether_header_t eth;
+ char optcpy[48], ol;
+ char *s;
+ int i, sent = 0, ts, hlen, olen;
+
+ hlen = IP_HL(ip) << 2;
+ if (mtu < (hlen + 8)) {
+ fprintf(stderr, "mtu (%d) < ip header size (%d) + 8\n",
+ mtu, hlen);
+ fprintf(stderr, "can't fragment data\n");
+ return -2;
+ }
+ ol = (IP_HL(ip) << 2) - sizeof(*ip);
+ for (i = 0, s = (char*)(ip + 1); ol > 0; )
+ if (*s == IPOPT_EOL) {
+ optcpy[i++] = *s;
+ break;
+ } else if (*s == IPOPT_NOP) {
+ s++;
+ ol--;
+ } else
+ {
+ olen = (int)(*(u_char *)(s + 1));
+ ol -= olen;
+ if (IPOPT_COPIED(*s))
+ {
+ bcopy(s, optcpy + i, olen);
+ i += olen;
+ s += olen;
+ }
+ }
+ if (i)
+ {
+ /*
+ * pad out
+ */
+ while ((i & 3) && (i & 3) != 3)
+ optcpy[i++] = IPOPT_NOP;
+ if ((i & 3) == 3)
+ optcpy[i++] = IPOPT_EOL;
+ }
+
+ bcopy((char *)eh, (char *)&eth, sizeof(eth));
+ s = (char *)ip + hlen;
+ iplen = ntohs(ip->ip_len) - hlen;
+ ip->ip_off |= htons(IP_MF);
+
+ while (1)
+ {
+ if ((sent + (mtu - hlen)) >= iplen)
+ {
+ ip->ip_off ^= htons(IP_MF);
+ ts = iplen - sent;
+ }
+ else
+ ts = (mtu - hlen);
+ ip->ip_off &= htons(0xe000);
+ ip->ip_off |= htons(sent >> 3);
+ ts += hlen;
+ ip->ip_len = htons(ts);
+ ip->ip_sum = 0;
+ ip->ip_sum = chksum((u_short *)ip, hlen);
+ bcopy((char *)ip, ipbuf + sizeof(*eh), hlen);
+ bcopy(s + sent, ipbuf + sizeof(*eh) + hlen, ts - hlen);
+ err = sendip(nfd, ipbuf, sizeof(*eh) + ts);
+
+ bcopy((char *)&eth, ipbuf, sizeof(eth));
+ sent += (ts - hlen);
+ if (!(ntohs(ip->ip_off) & IP_MF))
+ break;
+ else if (!(ip->ip_off & htons(0x1fff)))
+ {
+ hlen = i + sizeof(*ip);
+ IP_HL_A(ip, (sizeof(*ip) + i) >> 2);
+ bcopy(optcpy, (char *)(ip + 1), i);
+ }
+ }
+ }
+
+ bcopy((char *)&ipsv, (char *)ip, sizeof(*ip));
+ return err;
+}
+
+
+/*
+ * send a tcp packet.
+ */
+int send_tcp(nfd, mtu, ip, gwip)
+int nfd, mtu;
+ip_t *ip;
+struct in_addr gwip;
+{
+ static tcp_seq iss = 2;
+ tcphdr_t *t, *t2;
+ int thlen, i, iplen, hlen;
+ u_32_t lbuf[20];
+ ip_t *ip2;
+
+ iplen = ip->ip_len;
+ hlen = IP_HL(ip) << 2;
+ t = (tcphdr_t *)((char *)ip + hlen);
+ ip2 = (struct ip *)lbuf;
+ t2 = (tcphdr_t *)((char *)ip2 + hlen);
+ thlen = TCP_OFF(t) << 2;
+ if (!thlen)
+ thlen = sizeof(tcphdr_t);
+ bzero((char *)ip2, sizeof(*ip2) + sizeof(*t2));
+ ip->ip_p = IPPROTO_TCP;
+ ip2->ip_p = ip->ip_p;
+ ip2->ip_src = ip->ip_src;
+ ip2->ip_dst = ip->ip_dst;
+ bcopy((char *)ip + hlen, (char *)t2, thlen);
+
+ if (!t2->th_win)
+ t2->th_win = htons(4096);
+ iss += 63;
+
+ i = sizeof(struct tcpiphdr) / sizeof(long);
+
+ if ((t2->th_flags == TH_SYN) && !ntohs(ip->ip_off) &&
+ (lbuf[i] != htonl(0x020405b4))) {
+ lbuf[i] = htonl(0x020405b4);
+ bcopy((char *)ip + hlen + thlen, (char *)ip + hlen + thlen + 4,
+ iplen - thlen - hlen);
+ thlen += 4;
+ }
+ TCP_OFF_A(t2, thlen >> 2);
+ ip2->ip_len = htons(thlen);
+ ip->ip_len = hlen + thlen;
+ t2->th_sum = 0;
+ t2->th_sum = chksum((u_short *)ip2, thlen + sizeof(ip_t));
+
+ bcopy((char *)t2, (char *)ip + hlen, thlen);
+ return send_ip(nfd, mtu, ip, gwip, 1);
+}
+
+
+/*
+ * send a udp packet.
+ */
+int send_udp(nfd, mtu, ip, gwip)
+int nfd, mtu;
+ip_t *ip;
+struct in_addr gwip;
+{
+ struct tcpiphdr *ti;
+ int thlen;
+ u_long lbuf[20];
+
+ ti = (struct tcpiphdr *)lbuf;
+ bzero((char *)ti, sizeof(*ti));
+ thlen = sizeof(udphdr_t);
+ ti->ti_pr = ip->ip_p;
+ ti->ti_src = ip->ip_src;
+ ti->ti_dst = ip->ip_dst;
+ bcopy((char *)ip + (IP_HL(ip) << 2),
+ (char *)&ti->ti_sport, sizeof(udphdr_t));
+
+ ti->ti_len = htons(thlen);
+ ip->ip_len = (IP_HL(ip) << 2) + thlen;
+ ti->ti_sum = 0;
+ ti->ti_sum = chksum((u_short *)ti, thlen + sizeof(ip_t));
+
+ bcopy((char *)&ti->ti_sport,
+ (char *)ip + (IP_HL(ip) << 2), sizeof(udphdr_t));
+ return send_ip(nfd, mtu, ip, gwip, 1);
+}
+
+
+/*
+ * send an icmp packet.
+ */
+int send_icmp(nfd, mtu, ip, gwip)
+int nfd, mtu;
+ip_t *ip;
+struct in_addr gwip;
+{
+ struct icmp *ic;
+
+ ic = (struct icmp *)((char *)ip + (IP_HL(ip) << 2));
+
+ ic->icmp_cksum = 0;
+ ic->icmp_cksum = chksum((u_short *)ic, sizeof(struct icmp));
+
+ return send_ip(nfd, mtu, ip, gwip, 1);
+}
+
+
+int send_packet(nfd, mtu, ip, gwip)
+int nfd, mtu;
+ip_t *ip;
+struct in_addr gwip;
+{
+ switch (ip->ip_p)
+ {
+ case IPPROTO_TCP :
+ return send_tcp(nfd, mtu, ip, gwip);
+ case IPPROTO_UDP :
+ return send_udp(nfd, mtu, ip, gwip);
+ case IPPROTO_ICMP :
+ return send_icmp(nfd, mtu, ip, gwip);
+ default :
+ return send_ip(nfd, mtu, ip, gwip, 1);
+ }
+}
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