2 * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
3 * The Regents of the University of California. All rights reserved.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that: (1) source code distributions
7 * retain the above copyright notice and this paragraph in its entirety, (2)
8 * distributions including binary code include the above copyright notice and
9 * this paragraph in its entirety in the documentation or other materials
10 * provided with the distribution, and (3) all advertising materials mentioning
11 * features or use of this software display the following acknowledgement:
12 * ``This product includes software developed by the University of California,
13 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
14 * the University nor the names of its contributors may be used to endorse
15 * or promote products derived from this software without specific prior
17 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
18 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
19 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
25 static const char rcsid[] _U_ =
26 "@(#) $Header: /tcpdump/master/tcpdump/print-ip.c,v 1.149.2.2 2005/09/20 06:05:38 guy Exp $ (LBL)";
33 #include <tcpdump-stdinc.h>
39 #include "addrtoname.h"
40 #include "interface.h"
41 #include "extract.h" /* must come after interface.h */
46 struct tok ip_option_values[] = {
49 { IPOPT_TS, "timestamp" },
50 { IPOPT_SECURITY, "security" },
52 { IPOPT_SSRR, "SSRR" },
53 { IPOPT_LSRR, "LSRR" },
59 * print the recorded route in an IP RR, LSRR or SSRR option.
62 ip_printroute(register const u_char *cp, u_int length)
68 printf(" [bad length %u]", length);
72 printf(" [bad length %u]", length);
74 if (ptr < 3 || ((ptr + 1) & 3) || ptr > length + 1)
75 printf(" [bad ptr %u]", cp[2]);
77 for (len = 3; len < length; len += 4) {
78 printf("%s", ipaddr_string(&cp[len]));
85 * If source-routing is present and valid, return the final destination.
86 * Otherwise, return IP destination.
88 * This is used for UDP and TCP pseudo-header in the checksum
92 ip_finddst(const struct ip *ip)
99 cp = (const u_char *)(ip + 1);
100 length = (IP_HL(ip) << 2) - sizeof(struct ip);
102 for (; length > 0; cp += len, length -= len) {
109 else if (tt == IPOPT_NOP)
124 memcpy(&retval, cp + len - 4, 4);
129 memcpy(&retval, &ip->ip_dst.s_addr, sizeof(u_int32_t));
134 ip_printts(register const u_char *cp, u_int length)
142 printf("[bad length %d]", length);
146 hoplen = ((cp[3]&0xF) != IPOPT_TS_TSONLY) ? 8 : 4;
147 if ((length - 4) & (hoplen-1))
148 printf("[bad length %d]", length);
151 if (ptr < 4 || ((ptr - 4) & (hoplen-1)) || ptr > length + 1)
152 printf("[bad ptr %d]", cp[2]);
154 case IPOPT_TS_TSONLY:
157 case IPOPT_TS_TSANDADDR:
161 * prespecified should really be 3, but some ones might send 2
162 * instead, and the IPOPT_TS_PRESPEC constant can apparently
163 * have both values, so we have to hard-code it here.
167 printf("PRESPEC2.0");
169 case 3: /* IPOPT_TS_PRESPEC */
173 printf("[bad ts type %d]", cp[3]&0xF);
178 for (len = 4; len < length; len += hoplen) {
181 printf("%s%d@%s", type, EXTRACT_32BITS(&cp[len+hoplen-4]),
182 hoplen!=8 ? "" : ipaddr_string(&cp[len]));
187 printf("%s", ptr == len ? " ^ " : "");
190 printf(" [%d hops not recorded]} ", cp[3]>>4);
199 ip_optprint(register const u_char *cp, u_int length)
201 register u_int option_len;
203 for (; length > 0; cp += option_len, length -= option_len) {
209 if (option_code == IPOPT_NOP ||
210 option_code == IPOPT_EOL)
218 printf("%s (%u) len %u",
219 tok2str(ip_option_values,"unknown",option_code),
226 TCHECK2(*cp, option_len);
228 switch (option_code) {
233 ip_printts(cp, option_len);
236 case IPOPT_RR: /* fall through */
239 ip_printroute( cp, option_len);
244 if (EXTRACT_16BITS(&cp[2]) != 0)
245 printf("value %u", EXTRACT_16BITS(&cp[2]));
248 case IPOPT_NOP: /* nothing to print - fall through */
261 * compute an IP header checksum.
262 * don't modifiy the packet.
265 in_cksum(const u_short *addr, register u_int len, int csum)
268 const u_short *w = addr;
273 * Our algorithm is simple, using a 32 bit accumulator (sum),
274 * we add sequential 16 bit words to it, and at the end, fold
275 * back all the carry bits from the top 16 bits into the lower
283 sum += htons(*(u_char *)w<<8);
286 * add back carry outs from top 16 bits to low 16 bits
288 sum = (sum >> 16) + (sum & 0xffff); /* add hi 16 to low 16 */
289 sum += (sum >> 16); /* add carry */
290 answer = ~sum; /* truncate to 16 bits */
295 * Given the host-byte-order value of the checksum field in a packet
296 * header, and the network-byte-order computed checksum of the data
297 * that the checksum covers (including the checksum itself), compute
298 * what the checksum field *should* have been.
301 in_cksum_shouldbe(u_int16_t sum, u_int16_t computed_sum)
306 * The value that should have gone into the checksum field
307 * is the negative of the value gotten by summing up everything
308 * *but* the checksum field.
310 * We can compute that by subtracting the value of the checksum
311 * field from the sum of all the data in the packet, and then
312 * computing the negative of that value.
314 * "sum" is the value of the checksum field, and "computed_sum"
315 * is the negative of the sum of all the data in the packets,
316 * so that's -(-computed_sum - sum), or (sum + computed_sum).
318 * All the arithmetic in question is one's complement, so the
319 * addition must include an end-around carry; we do this by
320 * doing the arithmetic in 32 bits (with no sign-extension),
321 * and then adding the upper 16 bits of the sum, which contain
322 * the carry, to the lower 16 bits of the sum, and then do it
323 * again in case *that* sum produced a carry.
325 * As RFC 1071 notes, the checksum can be computed without
326 * byte-swapping the 16-bit words; summing 16-bit words
327 * on a big-endian machine gives a big-endian checksum, which
328 * can be directly stuffed into the big-endian checksum fields
329 * in protocol headers, and summing words on a little-endian
330 * machine gives a little-endian checksum, which must be
331 * byte-swapped before being stuffed into a big-endian checksum
334 * "computed_sum" is a network-byte-order value, so we must put
335 * it in host byte order before subtracting it from the
336 * host-byte-order value from the header; the adjusted checksum
337 * will be in host byte order, which is what we'll return.
340 shouldbe += ntohs(computed_sum);
341 shouldbe = (shouldbe & 0xFFFF) + (shouldbe >> 16);
342 shouldbe = (shouldbe & 0xFFFF) + (shouldbe >> 16);
352 #define IP_RES 0x8000
354 static struct tok ip_frag_values[] = {
357 { IP_RES, "rsvd" }, /* The RFC3514 evil ;-) bit */
361 struct ip_print_demux_state {
370 ip_print_demux(netdissect_options *ndo,
371 struct ip_print_demux_state *ipds)
373 struct protoent *proto;
379 ipds->nh = *ipds->cp;
380 ipds->advance = ah_print(ipds->cp);
381 if (ipds->advance <= 0)
383 ipds->cp += ipds->advance;
384 ipds->len -= ipds->advance;
390 ipds->advance = esp_print(ndo, ipds->cp, ipds->len,
391 (const u_char *)ipds->ip,
393 if (ipds->advance <= 0)
395 ipds->cp += ipds->advance;
396 ipds->len -= ipds->advance + padlen;
397 ipds->nh = enh & 0xff;
404 ipds->advance = ipcomp_print(ipds->cp, &enh);
405 if (ipds->advance <= 0)
407 ipds->cp += ipds->advance;
408 ipds->len -= ipds->advance;
409 ipds->nh = enh & 0xff;
414 sctp_print(ipds->cp, (const u_char *)ipds->ip, ipds->len);
418 dccp_print(ipds->cp, (const u_char *)ipds->ip, ipds->len);
422 tcp_print(ipds->cp, ipds->len, (const u_char *)ipds->ip,
423 (ipds->off &~ 0x6000));
427 udp_print(ipds->cp, ipds->len, (const u_char *)ipds->ip,
428 (ipds->off &~ 0x6000));
432 /* pass on the MF bit plus the offset to detect fragments */
433 icmp_print(ipds->cp, ipds->len, (const u_char *)ipds->ip,
434 (ipds->off & 0x3fff));
439 * XXX - the current IANA protocol number assignments
440 * page lists 9 as "any private interior gateway
441 * (used by Cisco for their IGRP)" and 88 as
442 * "EIGRP" from Cisco.
444 * Recent BSD <netinet/in.h> headers define
445 * IP_PROTO_PIGP as 9 and IP_PROTO_IGRP as 88.
446 * We define IP_PROTO_PIGP as 9 and
447 * IP_PROTO_EIGRP as 88; those names better
448 * match was the current protocol number
451 igrp_print(ipds->cp, ipds->len, (const u_char *)ipds->ip);
455 eigrp_print(ipds->cp, ipds->len);
459 ND_PRINT((ndo, " nd %d", ipds->len));
463 egp_print(ipds->cp, ipds->len);
467 ospf_print(ipds->cp, ipds->len, (const u_char *)ipds->ip);
471 igmp_print(ipds->cp, ipds->len);
475 /* DVMRP multicast tunnel (ip-in-ip encapsulation) */
476 ip_print(gndo, ipds->cp, ipds->len);
478 ND_PRINT((ndo, " (ipip-proto-4)"));
485 /* ip6-in-ip encapsulation */
486 ip6_print(ipds->cp, ipds->len);
491 rsvp_print(ipds->cp, ipds->len);
496 gre_print(ipds->cp, ipds->len);
500 mobile_print(ipds->cp, ipds->len);
504 pim_print(ipds->cp, ipds->len);
508 vrrp_print(ipds->cp, ipds->len, ipds->ip->ip_ttl);
512 pgm_print(ipds->cp, ipds->len, (const u_char *)ipds->ip);
516 if ((proto = getprotobynumber(ipds->nh)) != NULL)
517 ND_PRINT((ndo, " %s", proto->p_name));
519 ND_PRINT((ndo, " ip-proto-%d", ipds->nh));
520 ND_PRINT((ndo, " %d", ipds->len));
526 ip_print_inner(netdissect_options *ndo,
528 u_int length, u_int nh,
531 struct ip_print_demux_state ipd;
533 ipd.ip = (const struct ip *)bp2;
540 ip_print_demux(ndo, &ipd);
545 * print an IP datagram.
548 ip_print(netdissect_options *ndo,
552 struct ip_print_demux_state ipd;
553 struct ip_print_demux_state *ipds=&ipd;
556 u_int16_t sum, ip_sum;
557 struct protoent *proto;
559 ipds->ip = (const struct ip *)bp;
560 if (IP_V(ipds->ip) != 4) { /* print version if != 4 */
561 printf("IP%u ", IP_V(ipds->ip));
562 if (IP_V(ipds->ip) == 6)
563 printf(", wrong link-layer encapsulation");
568 if ((u_char *)(ipds->ip + 1) > snapend) {
572 if (length < sizeof (struct ip)) {
573 (void)printf("truncated-ip %u", length);
576 hlen = IP_HL(ipds->ip) * 4;
577 if (hlen < sizeof (struct ip)) {
578 (void)printf("bad-hlen %u", hlen);
582 ipds->len = EXTRACT_16BITS(&ipds->ip->ip_len);
583 if (length < ipds->len)
584 (void)printf("truncated-ip - %u bytes missing! ",
586 if (ipds->len < hlen) {
589 (void)printf("bad-len %u", ipds->len);
593 /* we guess that it is a TSO send */
597 (void)printf("bad-len %u", ipds->len);
599 #endif /* GUESS_TSO */
603 * Cut off the snapshot length to the end of the IP payload.
605 ipend = bp + ipds->len;
611 ipds->off = EXTRACT_16BITS(&ipds->ip->ip_off);
614 (void)printf("(tos 0x%x", (int)ipds->ip->ip_tos);
616 if (ipds->ip->ip_tos & 0x03) {
617 switch (ipds->ip->ip_tos & 0x03) {
619 (void)printf(",ECT(1)");
622 (void)printf(",ECT(0)");
629 if (ipds->ip->ip_ttl >= 1)
630 (void)printf(", ttl %3u", ipds->ip->ip_ttl);
633 * for the firewall guys, print id, offset.
634 * On all but the last stick a "+" in the flags portion.
635 * For unfragmented datagrams, note the don't fragment flag.
638 (void)printf(", id %u, offset %u, flags [%s], proto: %s (%u)",
639 EXTRACT_16BITS(&ipds->ip->ip_id),
640 (ipds->off & 0x1fff) * 8,
641 bittok2str(ip_frag_values, "none", ipds->off&0xe000 ),
642 tok2str(ipproto_values,"unknown",ipds->ip->ip_p),
645 (void)printf(", length: %u", EXTRACT_16BITS(&ipds->ip->ip_len));
647 if ((hlen - sizeof(struct ip)) > 0) {
648 printf(", options ( ");
649 ip_optprint((u_char *)(ipds->ip + 1), hlen - sizeof(struct ip));
653 if ((u_char *)ipds->ip + hlen <= snapend) {
654 sum = in_cksum((const u_short *)ipds->ip, hlen, 0);
656 ip_sum = EXTRACT_16BITS(&ipds->ip->ip_sum);
657 (void)printf(", bad cksum %x (->%x)!", ip_sum,
658 in_cksum_shouldbe(ip_sum, sum));
666 * If this is fragment zero, hand it to the next higher
669 if ((ipds->off & 0x1fff) == 0) {
670 ipds->cp = (const u_char *)ipds->ip + hlen;
671 ipds->nh = ipds->ip->ip_p;
673 if (ipds->nh != IPPROTO_TCP && ipds->nh != IPPROTO_UDP &&
674 ipds->nh != IPPROTO_SCTP && ipds->nh != IPPROTO_DCCP) {
675 (void)printf("%s > %s: ",
676 ipaddr_string(&ipds->ip->ip_src),
677 ipaddr_string(&ipds->ip->ip_dst));
679 ip_print_demux(ndo, ipds);
681 /* Ultra quiet now means that all this stuff should be suppressed */
682 if (qflag > 1) return;
685 * if this isn't the first frag, we're missing the
686 * next level protocol header. print the ip addr
689 if (ipds->off & 0x1fff) {
690 (void)printf("%s > %s:", ipaddr_string(&ipds->ip->ip_src),
691 ipaddr_string(&ipds->ip->ip_dst));
692 if ((proto = getprotobynumber(ipds->ip->ip_p)) != NULL)
693 (void)printf(" %s", proto->p_name);
695 (void)printf(" ip-proto-%d", ipds->ip->ip_p);
701 ipN_print(register const u_char *bp, register u_int length)
705 ip = (struct ip *)bp;
707 (void)printf("truncated-ip %d", length);
710 memcpy (&hdr, (char *)ip, 4);
711 switch (IP_V(&hdr)) {
713 ip_print (gndo, bp, length);
717 ip6_print (bp, length);
721 (void)printf("unknown ip %d", IP_V(&hdr));
728 * c-style: whitesmith