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.
23 static const char rcsid[] _U_ =
24 "@(#) $Header: /tcpdump/master/tcpdump/print-ip.c,v 1.149.2.8 2007/01/29 20:57:47 guy Exp $ (LBL)";
31 #include <tcpdump-stdinc.h>
37 #include "addrtoname.h"
38 #include "interface.h"
39 #include "extract.h" /* must come after interface.h */
44 struct tok ip_option_values[] = {
47 { IPOPT_TS, "timestamp" },
48 { IPOPT_SECURITY, "security" },
50 { IPOPT_SSRR, "SSRR" },
51 { IPOPT_LSRR, "LSRR" },
57 * print the recorded route in an IP RR, LSRR or SSRR option.
60 ip_printroute(register const u_char *cp, u_int length)
66 printf(" [bad length %u]", length);
70 printf(" [bad length %u]", length);
72 if (ptr < 3 || ((ptr + 1) & 3) || ptr > length + 1)
73 printf(" [bad ptr %u]", cp[2]);
75 for (len = 3; len < length; len += 4) {
76 printf(" %s", ipaddr_string(&cp[len]));
83 * If source-routing is present and valid, return the final destination.
84 * Otherwise, return IP destination.
86 * This is used for UDP and TCP pseudo-header in the checksum
90 ip_finddst(const struct ip *ip)
97 cp = (const u_char *)(ip + 1);
98 length = (IP_HL(ip) << 2) - sizeof(struct ip);
100 for (; length > 0; cp += len, length -= len) {
107 else if (tt == IPOPT_NOP)
122 memcpy(&retval, cp + len - 4, 4);
127 memcpy(&retval, &ip->ip_dst.s_addr, sizeof(u_int32_t));
132 ip_printts(register const u_char *cp, u_int length)
140 printf("[bad length %u]", length);
144 hoplen = ((cp[3]&0xF) != IPOPT_TS_TSONLY) ? 8 : 4;
145 if ((length - 4) & (hoplen-1))
146 printf("[bad length %u]", length);
149 if (ptr < 4 || ((ptr - 4) & (hoplen-1)) || ptr > length + 1)
150 printf("[bad ptr %u]", cp[2]);
152 case IPOPT_TS_TSONLY:
155 case IPOPT_TS_TSANDADDR:
159 * prespecified should really be 3, but some ones might send 2
160 * instead, and the IPOPT_TS_PRESPEC constant can apparently
161 * have both values, so we have to hard-code it here.
165 printf("PRESPEC2.0");
167 case 3: /* IPOPT_TS_PRESPEC */
171 printf("[bad ts type %d]", cp[3]&0xF);
176 for (len = 4; len < length; len += hoplen) {
179 printf("%s%d@%s", type, EXTRACT_32BITS(&cp[len+hoplen-4]),
180 hoplen!=8 ? "" : ipaddr_string(&cp[len]));
185 printf("%s", ptr == len ? " ^ " : "");
188 printf(" [%d hops not recorded]} ", cp[3]>>4);
197 ip_optprint(register const u_char *cp, u_int length)
199 register u_int option_len;
200 const char *sep = "";
202 for (; length > 0; cp += option_len, length -= option_len) {
212 tok2str(ip_option_values,"unknown %u",option_code));
214 if (option_code == IPOPT_NOP ||
215 option_code == IPOPT_EOL)
221 if (option_len < 2) {
222 printf(" [bad length %u]", option_len);
227 if (option_len > length) {
228 printf(" [bad length %u]", option_len);
232 TCHECK2(*cp, option_len);
234 switch (option_code) {
239 ip_printts(cp, option_len);
242 case IPOPT_RR: /* fall through */
245 ip_printroute(cp, option_len);
249 if (option_len < 4) {
250 printf(" [bad length %u]", option_len);
254 if (EXTRACT_16BITS(&cp[2]) != 0)
255 printf(" value %u", EXTRACT_16BITS(&cp[2]));
258 case IPOPT_NOP: /* nothing to print - fall through */
271 * compute an IP header checksum.
272 * don't modifiy the packet.
275 in_cksum(const u_short *addr, register u_int len, int csum)
278 const u_short *w = addr;
283 * Our algorithm is simple, using a 32 bit accumulator (sum),
284 * we add sequential 16 bit words to it, and at the end, fold
285 * back all the carry bits from the top 16 bits into the lower
293 sum += htons(*(u_char *)w<<8);
296 * add back carry outs from top 16 bits to low 16 bits
298 sum = (sum >> 16) + (sum & 0xffff); /* add hi 16 to low 16 */
299 sum += (sum >> 16); /* add carry */
300 answer = ~sum; /* truncate to 16 bits */
305 * Given the host-byte-order value of the checksum field in a packet
306 * header, and the network-byte-order computed checksum of the data
307 * that the checksum covers (including the checksum itself), compute
308 * what the checksum field *should* have been.
311 in_cksum_shouldbe(u_int16_t sum, u_int16_t computed_sum)
316 * The value that should have gone into the checksum field
317 * is the negative of the value gotten by summing up everything
318 * *but* the checksum field.
320 * We can compute that by subtracting the value of the checksum
321 * field from the sum of all the data in the packet, and then
322 * computing the negative of that value.
324 * "sum" is the value of the checksum field, and "computed_sum"
325 * is the negative of the sum of all the data in the packets,
326 * so that's -(-computed_sum - sum), or (sum + computed_sum).
328 * All the arithmetic in question is one's complement, so the
329 * addition must include an end-around carry; we do this by
330 * doing the arithmetic in 32 bits (with no sign-extension),
331 * and then adding the upper 16 bits of the sum, which contain
332 * the carry, to the lower 16 bits of the sum, and then do it
333 * again in case *that* sum produced a carry.
335 * As RFC 1071 notes, the checksum can be computed without
336 * byte-swapping the 16-bit words; summing 16-bit words
337 * on a big-endian machine gives a big-endian checksum, which
338 * can be directly stuffed into the big-endian checksum fields
339 * in protocol headers, and summing words on a little-endian
340 * machine gives a little-endian checksum, which must be
341 * byte-swapped before being stuffed into a big-endian checksum
344 * "computed_sum" is a network-byte-order value, so we must put
345 * it in host byte order before subtracting it from the
346 * host-byte-order value from the header; the adjusted checksum
347 * will be in host byte order, which is what we'll return.
350 shouldbe += ntohs(computed_sum);
351 shouldbe = (shouldbe & 0xFFFF) + (shouldbe >> 16);
352 shouldbe = (shouldbe & 0xFFFF) + (shouldbe >> 16);
356 #define IP_RES 0x8000
358 static struct tok ip_frag_values[] = {
361 { IP_RES, "rsvd" }, /* The RFC3514 evil ;-) bit */
365 struct ip_print_demux_state {
374 ip_print_demux(netdissect_options *ndo,
375 struct ip_print_demux_state *ipds)
377 struct protoent *proto;
383 ipds->nh = *ipds->cp;
384 ipds->advance = ah_print(ipds->cp);
385 if (ipds->advance <= 0)
387 ipds->cp += ipds->advance;
388 ipds->len -= ipds->advance;
394 ipds->advance = esp_print(ndo, ipds->cp, ipds->len,
395 (const u_char *)ipds->ip,
397 if (ipds->advance <= 0)
399 ipds->cp += ipds->advance;
400 ipds->len -= ipds->advance + padlen;
401 ipds->nh = enh & 0xff;
408 ipds->advance = ipcomp_print(ipds->cp, &enh);
409 if (ipds->advance <= 0)
411 ipds->cp += ipds->advance;
412 ipds->len -= ipds->advance;
413 ipds->nh = enh & 0xff;
418 sctp_print(ipds->cp, (const u_char *)ipds->ip, ipds->len);
422 dccp_print(ipds->cp, (const u_char *)ipds->ip, ipds->len);
426 /* pass on the MF bit plus the offset to detect fragments */
427 tcp_print(ipds->cp, ipds->len, (const u_char *)ipds->ip,
428 ipds->off & (IP_MF|IP_OFFMASK));
432 /* pass on the MF bit plus the offset to detect fragments */
433 udp_print(ipds->cp, ipds->len, (const u_char *)ipds->ip,
434 ipds->off & (IP_MF|IP_OFFMASK));
438 /* pass on the MF bit plus the offset to detect fragments */
439 icmp_print(ipds->cp, ipds->len, (const u_char *)ipds->ip,
440 ipds->off & (IP_MF|IP_OFFMASK));
445 * XXX - the current IANA protocol number assignments
446 * page lists 9 as "any private interior gateway
447 * (used by Cisco for their IGRP)" and 88 as
448 * "EIGRP" from Cisco.
450 * Recent BSD <netinet/in.h> headers define
451 * IP_PROTO_PIGP as 9 and IP_PROTO_IGRP as 88.
452 * We define IP_PROTO_PIGP as 9 and
453 * IP_PROTO_EIGRP as 88; those names better
454 * match was the current protocol number
457 igrp_print(ipds->cp, ipds->len, (const u_char *)ipds->ip);
461 eigrp_print(ipds->cp, ipds->len);
465 ND_PRINT((ndo, " nd %d", ipds->len));
469 egp_print(ipds->cp, ipds->len);
473 ospf_print(ipds->cp, ipds->len, (const u_char *)ipds->ip);
477 igmp_print(ipds->cp, ipds->len);
481 /* DVMRP multicast tunnel (ip-in-ip encapsulation) */
482 ip_print(gndo, ipds->cp, ipds->len);
484 ND_PRINT((ndo, " (ipip-proto-4)"));
491 /* ip6-in-ip encapsulation */
492 ip6_print(ipds->cp, ipds->len);
497 rsvp_print(ipds->cp, ipds->len);
502 gre_print(ipds->cp, ipds->len);
506 mobile_print(ipds->cp, ipds->len);
510 pim_print(ipds->cp, ipds->len);
514 vrrp_print(ipds->cp, ipds->len, ipds->ip->ip_ttl);
518 pgm_print(ipds->cp, ipds->len, (const u_char *)ipds->ip);
522 if ((proto = getprotobynumber(ipds->nh)) != NULL)
523 ND_PRINT((ndo, " %s", proto->p_name));
525 ND_PRINT((ndo, " ip-proto-%d", ipds->nh));
526 ND_PRINT((ndo, " %d", ipds->len));
532 ip_print_inner(netdissect_options *ndo,
534 u_int length, u_int nh,
537 struct ip_print_demux_state ipd;
539 ipd.ip = (const struct ip *)bp2;
546 ip_print_demux(ndo, &ipd);
551 * print an IP datagram.
554 ip_print(netdissect_options *ndo,
558 struct ip_print_demux_state ipd;
559 struct ip_print_demux_state *ipds=&ipd;
562 u_int16_t sum, ip_sum;
563 struct protoent *proto;
565 ipds->ip = (const struct ip *)bp;
566 if (IP_V(ipds->ip) != 4) { /* print version if != 4 */
567 printf("IP%u ", IP_V(ipds->ip));
568 if (IP_V(ipds->ip) == 6)
569 printf(", wrong link-layer encapsulation");
574 if ((u_char *)(ipds->ip + 1) > snapend) {
578 if (length < sizeof (struct ip)) {
579 (void)printf("truncated-ip %u", length);
582 hlen = IP_HL(ipds->ip) * 4;
583 if (hlen < sizeof (struct ip)) {
584 (void)printf("bad-hlen %u", hlen);
588 ipds->len = EXTRACT_16BITS(&ipds->ip->ip_len);
589 if (length < ipds->len)
590 (void)printf("truncated-ip - %u bytes missing! ",
592 if (ipds->len < hlen) {
595 (void)printf("bad-len %u", ipds->len);
599 /* we guess that it is a TSO send */
603 (void)printf("bad-len %u", ipds->len);
605 #endif /* GUESS_TSO */
609 * Cut off the snapshot length to the end of the IP payload.
611 ipend = bp + ipds->len;
617 ipds->off = EXTRACT_16BITS(&ipds->ip->ip_off);
620 (void)printf("(tos 0x%x", (int)ipds->ip->ip_tos);
622 if (ipds->ip->ip_tos & 0x03) {
623 switch (ipds->ip->ip_tos & 0x03) {
625 (void)printf(",ECT(1)");
628 (void)printf(",ECT(0)");
635 if (ipds->ip->ip_ttl >= 1)
636 (void)printf(", ttl %u", ipds->ip->ip_ttl);
639 * for the firewall guys, print id, offset.
640 * On all but the last stick a "+" in the flags portion.
641 * For unfragmented datagrams, note the don't fragment flag.
644 (void)printf(", id %u, offset %u, flags [%s], proto %s (%u)",
645 EXTRACT_16BITS(&ipds->ip->ip_id),
646 (ipds->off & 0x1fff) * 8,
647 bittok2str(ip_frag_values, "none", ipds->off&0xe000),
648 tok2str(ipproto_values,"unknown",ipds->ip->ip_p),
651 (void)printf(", length %u", EXTRACT_16BITS(&ipds->ip->ip_len));
653 if ((hlen - sizeof(struct ip)) > 0) {
654 printf(", options (");
655 ip_optprint((u_char *)(ipds->ip + 1), hlen - sizeof(struct ip));
659 if ((u_char *)ipds->ip + hlen <= snapend) {
660 sum = in_cksum((const u_short *)ipds->ip, hlen, 0);
662 ip_sum = EXTRACT_16BITS(&ipds->ip->ip_sum);
663 (void)printf(", bad cksum %x (->%x)!", ip_sum,
664 in_cksum_shouldbe(ip_sum, sum));
672 * If this is fragment zero, hand it to the next higher
675 if ((ipds->off & 0x1fff) == 0) {
676 ipds->cp = (const u_char *)ipds->ip + hlen;
677 ipds->nh = ipds->ip->ip_p;
679 if (ipds->nh != IPPROTO_TCP && ipds->nh != IPPROTO_UDP &&
680 ipds->nh != IPPROTO_SCTP && ipds->nh != IPPROTO_DCCP) {
681 (void)printf("%s > %s: ",
682 ipaddr_string(&ipds->ip->ip_src),
683 ipaddr_string(&ipds->ip->ip_dst));
685 ip_print_demux(ndo, ipds);
687 /* Ultra quiet now means that all this stuff should be suppressed */
688 if (qflag > 1) return;
691 * if this isn't the first frag, we're missing the
692 * next level protocol header. print the ip addr
695 if (ipds->off & 0x1fff) {
696 (void)printf("%s > %s:", ipaddr_string(&ipds->ip->ip_src),
697 ipaddr_string(&ipds->ip->ip_dst));
698 if ((proto = getprotobynumber(ipds->ip->ip_p)) != NULL)
699 (void)printf(" %s", proto->p_name);
701 (void)printf(" ip-proto-%d", ipds->ip->ip_p);
707 ipN_print(register const u_char *bp, register u_int length)
711 ip = (struct ip *)bp;
713 (void)printf("truncated-ip %d", length);
716 memcpy (&hdr, (char *)ip, 4);
717 switch (IP_V(&hdr)) {
719 ip_print (gndo, bp, length);
723 ip6_print (bp, length);
727 (void)printf("unknown ip %d", IP_V(&hdr));
734 * c-style: whitesmith