1/*
2 * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
3 * The Regents of the University of California. All rights reserved.
4 *
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
16 * written permission.
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.
20 *
21 * $FreeBSD: head/contrib/tcpdump/print-ip.c 162021 2006-09-04 20:25:04Z sam $
22 */
23
24#ifndef lint
25static 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)";
27#endif
28
29#ifdef HAVE_CONFIG_H
30#include "config.h"
31#endif
32
33#include <tcpdump-stdinc.h>
34
35#include <stdio.h>
36#include <stdlib.h>
37#include <string.h>
38
39#include "addrtoname.h"
40#include "interface.h"
41#include "extract.h" /* must come after interface.h */
42
43#include "ip.h"
44#include "ipproto.h"
45
46struct tok ip_option_values[] = {
47 { IPOPT_EOL, "EOL" },
48 { IPOPT_NOP, "NOP" },
49 { IPOPT_TS, "timestamp" },
50 { IPOPT_SECURITY, "security" },
51 { IPOPT_RR, "RR" },
52 { IPOPT_SSRR, "SSRR" },
53 { IPOPT_LSRR, "LSRR" },
54 { IPOPT_RA, "RA" },
55 { 0, NULL }
56};
57
58/*
59 * print the recorded route in an IP RR, LSRR or SSRR option.
60 */
61static void
62ip_printroute(register const u_char *cp, u_int length)
63{
64 register u_int ptr;
65 register u_int len;
66
67 if (length < 3) {
68 printf(" [bad length %u]", length);
69 return;
70 }
71 if ((length + 1) & 3)
72 printf(" [bad length %u]", length);
73 ptr = cp[2] - 1;
74 if (ptr < 3 || ((ptr + 1) & 3) || ptr > length + 1)
75 printf(" [bad ptr %u]", cp[2]);
76
77 for (len = 3; len < length; len += 4) {
78 printf("%s", ipaddr_string(&cp[len]));
79 if (ptr > len)
80 printf (", ");
81 }
82}
83
84/*
85 * If source-routing is present and valid, return the final destination.
86 * Otherwise, return IP destination.
87 *
88 * This is used for UDP and TCP pseudo-header in the checksum
89 * calculation.
90 */
91u_int32_t
92ip_finddst(const struct ip *ip)
93{
94 int length;
95 int len;
96 const u_char *cp;
97 u_int32_t retval;
98
99 cp = (const u_char *)(ip + 1);
100 length = (IP_HL(ip) << 2) - sizeof(struct ip);
101
102 for (; length > 0; cp += len, length -= len) {
103 int tt;
104
105 TCHECK(*cp);
106 tt = *cp;
107 if (tt == IPOPT_EOL)
108 break;
109 else if (tt == IPOPT_NOP)
110 len = 1;
111 else {
112 TCHECK(cp[1]);
113 len = cp[1];
114 if (len < 2)
115 break;
116 }
117 TCHECK2(*cp, len);
118 switch (tt) {
119
120 case IPOPT_SSRR:
121 case IPOPT_LSRR:
122 if (len < 7)
123 break;
124 memcpy(&retval, cp + len - 4, 4);
125 return retval;
126 }
127 }
128trunc:
129 memcpy(&retval, &ip->ip_dst.s_addr, sizeof(u_int32_t));
130 return retval;
131}
132
133static void
134ip_printts(register const u_char *cp, u_int length)
135{
136 register u_int ptr;
137 register u_int len;
138 int hoplen;
139 const char *type;
140
141 if (length < 4) {
142 printf("[bad length %d]", length);
143 return;
144 }
145 printf(" TS{");
146 hoplen = ((cp[3]&0xF) != IPOPT_TS_TSONLY) ? 8 : 4;
147 if ((length - 4) & (hoplen-1))
148 printf("[bad length %d]", length);
149 ptr = cp[2] - 1;
150 len = 0;
151 if (ptr < 4 || ((ptr - 4) & (hoplen-1)) || ptr > length + 1)
152 printf("[bad ptr %d]", cp[2]);
153 switch (cp[3]&0xF) {
154 case IPOPT_TS_TSONLY:
155 printf("TSONLY");
156 break;
157 case IPOPT_TS_TSANDADDR:
158 printf("TS+ADDR");
159 break;
160 /*
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.
164 */
165
166 case 2:
167 printf("PRESPEC2.0");
168 break;
169 case 3: /* IPOPT_TS_PRESPEC */
170 printf("PRESPEC");
171 break;
172 default:
173 printf("[bad ts type %d]", cp[3]&0xF);
174 goto done;
175 }
176
177 type = " ";
178 for (len = 4; len < length; len += hoplen) {
179 if (ptr == len)
180 type = " ^ ";
181 printf("%s%d@%s", type, EXTRACT_32BITS(&cp[len+hoplen-4]),
182 hoplen!=8 ? "" : ipaddr_string(&cp[len]));
183 type = " ";
184 }
185
186done:
187 printf("%s", ptr == len ? " ^ " : "");
188
189 if (cp[3]>>4)
190 printf(" [%d hops not recorded]} ", cp[3]>>4);
191 else
192 printf("}");
193}
194
195/*
196 * print IP options.
197 */
198static void
199ip_optprint(register const u_char *cp, u_int length)
200{
201 register u_int option_len;
202
203 for (; length > 0; cp += option_len, length -= option_len) {
204 u_int option_code;
205
206 TCHECK(*cp);
207 option_code = *cp;
208
209 if (option_code == IPOPT_NOP ||
210 option_code == IPOPT_EOL)
211 option_len = 1;
212
213 else {
214 TCHECK(cp[1]);
215 option_len = cp[1];
216 }
217
218 printf("%s (%u) len %u",
219 tok2str(ip_option_values,"unknown",option_code),
220 option_code,
221 option_len);
222
223 if (option_len < 2)
224 return;
225
226 TCHECK2(*cp, option_len);
227
228 switch (option_code) {
229 case IPOPT_EOL:
230 return;
231
232 case IPOPT_TS:
233 ip_printts(cp, option_len);
234 break;
235
236 case IPOPT_RR: /* fall through */
237 case IPOPT_SSRR:
238 case IPOPT_LSRR:
239 ip_printroute( cp, option_len);
240 break;
241
242 case IPOPT_RA:
243 TCHECK(cp[3]);
244 if (EXTRACT_16BITS(&cp[2]) != 0)
245 printf("value %u", EXTRACT_16BITS(&cp[2]));
246 break;
247
248 case IPOPT_NOP: /* nothing to print - fall through */
249 case IPOPT_SECURITY:
250 default:
251 break;
252 }
253 }
254 return;
255
256trunc:
257 printf("[|ip]");
258}
259
260/*
261 * compute an IP header checksum.
262 * don't modifiy the packet.
263 */
264u_short
265in_cksum(const u_short *addr, register u_int len, int csum)
266{
267 int nleft = len;
268 const u_short *w = addr;
269 u_short answer;
270 int sum = csum;
271
272 /*
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
276 * 16 bits.
277 */
278 while (nleft > 1) {
279 sum += *w++;
280 nleft -= 2;
281 }
282 if (nleft == 1)
283 sum += htons(*(u_char *)w<<8);
284
285 /*
286 * add back carry outs from top 16 bits to low 16 bits
287 */
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 */
291 return (answer);
292}
293
294/*
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.
299 */
300u_int16_t
301in_cksum_shouldbe(u_int16_t sum, u_int16_t computed_sum)
302{
303 u_int32_t shouldbe;
304
305 /*
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.
309 *
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.
313 *
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).
317 *
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.
324 *
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
332 * field.
333 *
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.
338 */
339 shouldbe = sum;
340 shouldbe += ntohs(computed_sum);
341 shouldbe = (shouldbe & 0xFFFF) + (shouldbe >> 16);
342 shouldbe = (shouldbe & 0xFFFF) + (shouldbe >> 16);
343 return shouldbe;
344}
345
346#ifndef IP_MF
347#define IP_MF 0x2000
348#endif /* IP_MF */
349#ifndef IP_DF
350#define IP_DF 0x4000
351#endif /* IP_DF */
352#define IP_RES 0x8000
353
354static struct tok ip_frag_values[] = {
355 { IP_MF, "+" },
356 { IP_DF, "DF" },
357 { IP_RES, "rsvd" }, /* The RFC3514 evil ;-) bit */
358 { 0, NULL }
359};
360
361struct ip_print_demux_state {
362 const struct ip *ip;
363 const u_char *cp;
364 u_int len, off;
365 u_char nh;
366 int advance;
367};
368
369static void
370ip_print_demux(netdissect_options *ndo,
371 struct ip_print_demux_state *ipds)
372{
373 struct protoent *proto;
374
375again:
376 switch (ipds->nh) {
377
378 case IPPROTO_AH:
379 ipds->nh = *ipds->cp;
380 ipds->advance = ah_print(ipds->cp);
381 if (ipds->advance <= 0)
382 break;
383 ipds->cp += ipds->advance;
384 ipds->len -= ipds->advance;
385 goto again;
386
387 case IPPROTO_ESP:
388 {
389 int enh, padlen;
390 ipds->advance = esp_print(ndo, ipds->cp, ipds->len,
391 (const u_char *)ipds->ip,
392 &enh, &padlen);
393 if (ipds->advance <= 0)
394 break;
395 ipds->cp += ipds->advance;
396 ipds->len -= ipds->advance + padlen;
397 ipds->nh = enh & 0xff;
398 goto again;
399 }
400
401 case IPPROTO_IPCOMP:
402 {
403 int enh;
404 ipds->advance = ipcomp_print(ipds->cp, &enh);
405 if (ipds->advance <= 0)
406 break;
407 ipds->cp += ipds->advance;
408 ipds->len -= ipds->advance;
409 ipds->nh = enh & 0xff;
410 goto again;
411 }
412
413 case IPPROTO_SCTP:
414 sctp_print(ipds->cp, (const u_char *)ipds->ip, ipds->len);
415 break;
416
417 case IPPROTO_DCCP:
418 dccp_print(ipds->cp, (const u_char *)ipds->ip, ipds->len);
419 break;
420
421 case IPPROTO_TCP:
422 tcp_print(ipds->cp, ipds->len, (const u_char *)ipds->ip,
423 (ipds->off &~ 0x6000));
424 break;
425
426 case IPPROTO_UDP:
427 udp_print(ipds->cp, ipds->len, (const u_char *)ipds->ip,
428 (ipds->off &~ 0x6000));
429 break;
430
431 case IPPROTO_ICMP:
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));
435 break;
436
437 case IPPROTO_PIGP:
438 /*
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.
443 *
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
449 * assignments say.
450 */
451 igrp_print(ipds->cp, ipds->len, (const u_char *)ipds->ip);
452 break;
453
454 case IPPROTO_EIGRP:
455 eigrp_print(ipds->cp, ipds->len);
456 break;
457
458 case IPPROTO_ND:
459 ND_PRINT((ndo, " nd %d", ipds->len));
460 break;
461
462 case IPPROTO_EGP:
463 egp_print(ipds->cp, ipds->len);
464 break;
465
466 case IPPROTO_OSPF:
467 ospf_print(ipds->cp, ipds->len, (const u_char *)ipds->ip);
468 break;
469
470 case IPPROTO_IGMP:
471 igmp_print(ipds->cp, ipds->len);
472 break;
473
474 case IPPROTO_IPV4:
475 /* DVMRP multicast tunnel (ip-in-ip encapsulation) */
476 ip_print(gndo, ipds->cp, ipds->len);
477 if (! vflag) {
478 ND_PRINT((ndo, " (ipip-proto-4)"));
479 return;
480 }
481 break;
482
483#ifdef INET6
484 case IPPROTO_IPV6:
485 /* ip6-in-ip encapsulation */
486 ip6_print(ipds->cp, ipds->len);
487 break;
488#endif /*INET6*/
489
490 case IPPROTO_RSVP:
491 rsvp_print(ipds->cp, ipds->len);
492 break;
493
494 case IPPROTO_GRE:
495 /* do it */
496 gre_print(ipds->cp, ipds->len);
497 break;
498
499 case IPPROTO_MOBILE:
500 mobile_print(ipds->cp, ipds->len);
501 break;
502
503 case IPPROTO_PIM:
504 pim_print(ipds->cp, ipds->len);
505 break;
506
507 case IPPROTO_VRRP:
508 vrrp_print(ipds->cp, ipds->len, ipds->ip->ip_ttl);
509 break;
510
511 case IPPROTO_PGM:
512 pgm_print(ipds->cp, ipds->len, (const u_char *)ipds->ip);
513 break;
514
515 default:
516 if ((proto = getprotobynumber(ipds->nh)) != NULL)
517 ND_PRINT((ndo, " %s", proto->p_name));
518 else
519 ND_PRINT((ndo, " ip-proto-%d", ipds->nh));
520 ND_PRINT((ndo, " %d", ipds->len));
521 break;
522 }
523}
524
525void
526ip_print_inner(netdissect_options *ndo,
527 const u_char *bp,
528 u_int length, u_int nh,
529 const u_char *bp2)
530{
531 struct ip_print_demux_state ipd;
532
533 ipd.ip = (const struct ip *)bp2;
534 ipd.cp = bp;
535 ipd.len = length;
536 ipd.off = 0;
537 ipd.nh = nh;
538 ipd.advance = 0;
539
540 ip_print_demux(ndo, &ipd);
541}
542
543
544/*
545 * print an IP datagram.
546 */
547void
548ip_print(netdissect_options *ndo,
549 const u_char *bp,
550 u_int length)
551{
552 struct ip_print_demux_state ipd;
553 struct ip_print_demux_state *ipds=&ipd;
554 const u_char *ipend;
555 u_int hlen;
556 u_int16_t sum, ip_sum;
557 struct protoent *proto;
558
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");
564 }
565 else if (!eflag)
566 printf("IP ");
567
568 if ((u_char *)(ipds->ip + 1) > snapend) {
569 printf("[|ip]");
570 return;
571 }
572 if (length < sizeof (struct ip)) {
573 (void)printf("truncated-ip %u", length);
574 return;
575 }
576 hlen = IP_HL(ipds->ip) * 4;
577 if (hlen < sizeof (struct ip)) {
578 (void)printf("bad-hlen %u", hlen);
579 return;
580 }
581
582 ipds->len = EXTRACT_16BITS(&ipds->ip->ip_len);
583 if (length < ipds->len)
584 (void)printf("truncated-ip - %u bytes missing! ",
585 ipds->len - length);
586 if (ipds->len < hlen) {
587#ifdef GUESS_TSO
588 if (ipds->len) {
589 (void)printf("bad-len %u", ipds->len);
590 return;
591 }
592 else {
593 /* we guess that it is a TSO send */
594 ipds->len = length;
595 }
596#else
597 (void)printf("bad-len %u", ipds->len);
598 return;
599#endif /* GUESS_TSO */
600 }
601
602 /*
603 * Cut off the snapshot length to the end of the IP payload.
604 */
605 ipend = bp + ipds->len;
606 if (ipend < snapend)
607 snapend = ipend;
608
609 ipds->len -= hlen;
610
611 ipds->off = EXTRACT_16BITS(&ipds->ip->ip_off);
612
613 if (vflag) {
614 (void)printf("(tos 0x%x", (int)ipds->ip->ip_tos);
615 /* ECN bits */
616 if (ipds->ip->ip_tos & 0x03) {
617 switch (ipds->ip->ip_tos & 0x03) {
618 case 1:
619 (void)printf(",ECT(1)");
620 break;
621 case 2:
622 (void)printf(",ECT(0)");
623 break;
624 case 3:
625 (void)printf(",CE");
626 }
627 }
628
629 if (ipds->ip->ip_ttl >= 1)
630 (void)printf(", ttl %3u", ipds->ip->ip_ttl);
631
632 /*
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.
636 */
637
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),
643 ipds->ip->ip_p);
644
645 (void)printf(", length: %u", EXTRACT_16BITS(&ipds->ip->ip_len));
646
647 if ((hlen - sizeof(struct ip)) > 0) {
648 printf(", options ( ");
649 ip_optprint((u_char *)(ipds->ip + 1), hlen - sizeof(struct ip));
650 printf(" )");
651 }
652
653 if ((u_char *)ipds->ip + hlen <= snapend) {
654 sum = in_cksum((const u_short *)ipds->ip, hlen, 0);
655 if (sum != 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));
659 }
660 }
661
662 printf(") ");
663 }
664
665 /*
666 * If this is fragment zero, hand it to the next higher
667 * level protocol.
668 */
669 if ((ipds->off & 0x1fff) == 0) {
670 ipds->cp = (const u_char *)ipds->ip + hlen;
671 ipds->nh = ipds->ip->ip_p;
672
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));
678 }
679 ip_print_demux(ndo, ipds);
680 } else {
681 /* Ultra quiet now means that all this stuff should be suppressed */
682 if (qflag > 1) return;
683
684 /*
685 * if this isn't the first frag, we're missing the
686 * next level protocol header. print the ip addr
687 * and the protocol.
688 */
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);
694 else
695 (void)printf(" ip-proto-%d", ipds->ip->ip_p);
696 }
697 }
698}
699
700void
701ipN_print(register const u_char *bp, register u_int length)
702{
703 struct ip *ip, hdr;
704
705 ip = (struct ip *)bp;
706 if (length < 4) {
707 (void)printf("truncated-ip %d", length);
708 return;
709 }
710 memcpy (&hdr, (char *)ip, 4);
711 switch (IP_V(&hdr)) {
712 case 4:
713 ip_print (gndo, bp, length);
714 return;
715#ifdef INET6
716 case 6:
717 ip6_print (bp, length);
718 return;
719#endif
720 default:
721 (void)printf("unknown ip %d", IP_V(&hdr));
722 return;
723 }
724}
725
726/*
727 * Local Variables:
728 * c-style: whitesmith
729 * c-basic-offset: 8
730 * End:
731 */
732
733
2 * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
3 * The Regents of the University of California. All rights reserved.
4 *
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
16 * written permission.
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.
20 *
21 * $FreeBSD: head/contrib/tcpdump/print-ip.c 162021 2006-09-04 20:25:04Z sam $
22 */
23
24#ifndef lint
25static 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)";
27#endif
28
29#ifdef HAVE_CONFIG_H
30#include "config.h"
31#endif
32
33#include <tcpdump-stdinc.h>
34
35#include <stdio.h>
36#include <stdlib.h>
37#include <string.h>
38
39#include "addrtoname.h"
40#include "interface.h"
41#include "extract.h" /* must come after interface.h */
42
43#include "ip.h"
44#include "ipproto.h"
45
46struct tok ip_option_values[] = {
47 { IPOPT_EOL, "EOL" },
48 { IPOPT_NOP, "NOP" },
49 { IPOPT_TS, "timestamp" },
50 { IPOPT_SECURITY, "security" },
51 { IPOPT_RR, "RR" },
52 { IPOPT_SSRR, "SSRR" },
53 { IPOPT_LSRR, "LSRR" },
54 { IPOPT_RA, "RA" },
55 { 0, NULL }
56};
57
58/*
59 * print the recorded route in an IP RR, LSRR or SSRR option.
60 */
61static void
62ip_printroute(register const u_char *cp, u_int length)
63{
64 register u_int ptr;
65 register u_int len;
66
67 if (length < 3) {
68 printf(" [bad length %u]", length);
69 return;
70 }
71 if ((length + 1) & 3)
72 printf(" [bad length %u]", length);
73 ptr = cp[2] - 1;
74 if (ptr < 3 || ((ptr + 1) & 3) || ptr > length + 1)
75 printf(" [bad ptr %u]", cp[2]);
76
77 for (len = 3; len < length; len += 4) {
78 printf("%s", ipaddr_string(&cp[len]));
79 if (ptr > len)
80 printf (", ");
81 }
82}
83
84/*
85 * If source-routing is present and valid, return the final destination.
86 * Otherwise, return IP destination.
87 *
88 * This is used for UDP and TCP pseudo-header in the checksum
89 * calculation.
90 */
91u_int32_t
92ip_finddst(const struct ip *ip)
93{
94 int length;
95 int len;
96 const u_char *cp;
97 u_int32_t retval;
98
99 cp = (const u_char *)(ip + 1);
100 length = (IP_HL(ip) << 2) - sizeof(struct ip);
101
102 for (; length > 0; cp += len, length -= len) {
103 int tt;
104
105 TCHECK(*cp);
106 tt = *cp;
107 if (tt == IPOPT_EOL)
108 break;
109 else if (tt == IPOPT_NOP)
110 len = 1;
111 else {
112 TCHECK(cp[1]);
113 len = cp[1];
114 if (len < 2)
115 break;
116 }
117 TCHECK2(*cp, len);
118 switch (tt) {
119
120 case IPOPT_SSRR:
121 case IPOPT_LSRR:
122 if (len < 7)
123 break;
124 memcpy(&retval, cp + len - 4, 4);
125 return retval;
126 }
127 }
128trunc:
129 memcpy(&retval, &ip->ip_dst.s_addr, sizeof(u_int32_t));
130 return retval;
131}
132
133static void
134ip_printts(register const u_char *cp, u_int length)
135{
136 register u_int ptr;
137 register u_int len;
138 int hoplen;
139 const char *type;
140
141 if (length < 4) {
142 printf("[bad length %d]", length);
143 return;
144 }
145 printf(" TS{");
146 hoplen = ((cp[3]&0xF) != IPOPT_TS_TSONLY) ? 8 : 4;
147 if ((length - 4) & (hoplen-1))
148 printf("[bad length %d]", length);
149 ptr = cp[2] - 1;
150 len = 0;
151 if (ptr < 4 || ((ptr - 4) & (hoplen-1)) || ptr > length + 1)
152 printf("[bad ptr %d]", cp[2]);
153 switch (cp[3]&0xF) {
154 case IPOPT_TS_TSONLY:
155 printf("TSONLY");
156 break;
157 case IPOPT_TS_TSANDADDR:
158 printf("TS+ADDR");
159 break;
160 /*
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.
164 */
165
166 case 2:
167 printf("PRESPEC2.0");
168 break;
169 case 3: /* IPOPT_TS_PRESPEC */
170 printf("PRESPEC");
171 break;
172 default:
173 printf("[bad ts type %d]", cp[3]&0xF);
174 goto done;
175 }
176
177 type = " ";
178 for (len = 4; len < length; len += hoplen) {
179 if (ptr == len)
180 type = " ^ ";
181 printf("%s%d@%s", type, EXTRACT_32BITS(&cp[len+hoplen-4]),
182 hoplen!=8 ? "" : ipaddr_string(&cp[len]));
183 type = " ";
184 }
185
186done:
187 printf("%s", ptr == len ? " ^ " : "");
188
189 if (cp[3]>>4)
190 printf(" [%d hops not recorded]} ", cp[3]>>4);
191 else
192 printf("}");
193}
194
195/*
196 * print IP options.
197 */
198static void
199ip_optprint(register const u_char *cp, u_int length)
200{
201 register u_int option_len;
202
203 for (; length > 0; cp += option_len, length -= option_len) {
204 u_int option_code;
205
206 TCHECK(*cp);
207 option_code = *cp;
208
209 if (option_code == IPOPT_NOP ||
210 option_code == IPOPT_EOL)
211 option_len = 1;
212
213 else {
214 TCHECK(cp[1]);
215 option_len = cp[1];
216 }
217
218 printf("%s (%u) len %u",
219 tok2str(ip_option_values,"unknown",option_code),
220 option_code,
221 option_len);
222
223 if (option_len < 2)
224 return;
225
226 TCHECK2(*cp, option_len);
227
228 switch (option_code) {
229 case IPOPT_EOL:
230 return;
231
232 case IPOPT_TS:
233 ip_printts(cp, option_len);
234 break;
235
236 case IPOPT_RR: /* fall through */
237 case IPOPT_SSRR:
238 case IPOPT_LSRR:
239 ip_printroute( cp, option_len);
240 break;
241
242 case IPOPT_RA:
243 TCHECK(cp[3]);
244 if (EXTRACT_16BITS(&cp[2]) != 0)
245 printf("value %u", EXTRACT_16BITS(&cp[2]));
246 break;
247
248 case IPOPT_NOP: /* nothing to print - fall through */
249 case IPOPT_SECURITY:
250 default:
251 break;
252 }
253 }
254 return;
255
256trunc:
257 printf("[|ip]");
258}
259
260/*
261 * compute an IP header checksum.
262 * don't modifiy the packet.
263 */
264u_short
265in_cksum(const u_short *addr, register u_int len, int csum)
266{
267 int nleft = len;
268 const u_short *w = addr;
269 u_short answer;
270 int sum = csum;
271
272 /*
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
276 * 16 bits.
277 */
278 while (nleft > 1) {
279 sum += *w++;
280 nleft -= 2;
281 }
282 if (nleft == 1)
283 sum += htons(*(u_char *)w<<8);
284
285 /*
286 * add back carry outs from top 16 bits to low 16 bits
287 */
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 */
291 return (answer);
292}
293
294/*
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.
299 */
300u_int16_t
301in_cksum_shouldbe(u_int16_t sum, u_int16_t computed_sum)
302{
303 u_int32_t shouldbe;
304
305 /*
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.
309 *
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.
313 *
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).
317 *
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.
324 *
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
332 * field.
333 *
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.
338 */
339 shouldbe = sum;
340 shouldbe += ntohs(computed_sum);
341 shouldbe = (shouldbe & 0xFFFF) + (shouldbe >> 16);
342 shouldbe = (shouldbe & 0xFFFF) + (shouldbe >> 16);
343 return shouldbe;
344}
345
346#ifndef IP_MF
347#define IP_MF 0x2000
348#endif /* IP_MF */
349#ifndef IP_DF
350#define IP_DF 0x4000
351#endif /* IP_DF */
352#define IP_RES 0x8000
353
354static struct tok ip_frag_values[] = {
355 { IP_MF, "+" },
356 { IP_DF, "DF" },
357 { IP_RES, "rsvd" }, /* The RFC3514 evil ;-) bit */
358 { 0, NULL }
359};
360
361struct ip_print_demux_state {
362 const struct ip *ip;
363 const u_char *cp;
364 u_int len, off;
365 u_char nh;
366 int advance;
367};
368
369static void
370ip_print_demux(netdissect_options *ndo,
371 struct ip_print_demux_state *ipds)
372{
373 struct protoent *proto;
374
375again:
376 switch (ipds->nh) {
377
378 case IPPROTO_AH:
379 ipds->nh = *ipds->cp;
380 ipds->advance = ah_print(ipds->cp);
381 if (ipds->advance <= 0)
382 break;
383 ipds->cp += ipds->advance;
384 ipds->len -= ipds->advance;
385 goto again;
386
387 case IPPROTO_ESP:
388 {
389 int enh, padlen;
390 ipds->advance = esp_print(ndo, ipds->cp, ipds->len,
391 (const u_char *)ipds->ip,
392 &enh, &padlen);
393 if (ipds->advance <= 0)
394 break;
395 ipds->cp += ipds->advance;
396 ipds->len -= ipds->advance + padlen;
397 ipds->nh = enh & 0xff;
398 goto again;
399 }
400
401 case IPPROTO_IPCOMP:
402 {
403 int enh;
404 ipds->advance = ipcomp_print(ipds->cp, &enh);
405 if (ipds->advance <= 0)
406 break;
407 ipds->cp += ipds->advance;
408 ipds->len -= ipds->advance;
409 ipds->nh = enh & 0xff;
410 goto again;
411 }
412
413 case IPPROTO_SCTP:
414 sctp_print(ipds->cp, (const u_char *)ipds->ip, ipds->len);
415 break;
416
417 case IPPROTO_DCCP:
418 dccp_print(ipds->cp, (const u_char *)ipds->ip, ipds->len);
419 break;
420
421 case IPPROTO_TCP:
422 tcp_print(ipds->cp, ipds->len, (const u_char *)ipds->ip,
423 (ipds->off &~ 0x6000));
424 break;
425
426 case IPPROTO_UDP:
427 udp_print(ipds->cp, ipds->len, (const u_char *)ipds->ip,
428 (ipds->off &~ 0x6000));
429 break;
430
431 case IPPROTO_ICMP:
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));
435 break;
436
437 case IPPROTO_PIGP:
438 /*
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.
443 *
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
449 * assignments say.
450 */
451 igrp_print(ipds->cp, ipds->len, (const u_char *)ipds->ip);
452 break;
453
454 case IPPROTO_EIGRP:
455 eigrp_print(ipds->cp, ipds->len);
456 break;
457
458 case IPPROTO_ND:
459 ND_PRINT((ndo, " nd %d", ipds->len));
460 break;
461
462 case IPPROTO_EGP:
463 egp_print(ipds->cp, ipds->len);
464 break;
465
466 case IPPROTO_OSPF:
467 ospf_print(ipds->cp, ipds->len, (const u_char *)ipds->ip);
468 break;
469
470 case IPPROTO_IGMP:
471 igmp_print(ipds->cp, ipds->len);
472 break;
473
474 case IPPROTO_IPV4:
475 /* DVMRP multicast tunnel (ip-in-ip encapsulation) */
476 ip_print(gndo, ipds->cp, ipds->len);
477 if (! vflag) {
478 ND_PRINT((ndo, " (ipip-proto-4)"));
479 return;
480 }
481 break;
482
483#ifdef INET6
484 case IPPROTO_IPV6:
485 /* ip6-in-ip encapsulation */
486 ip6_print(ipds->cp, ipds->len);
487 break;
488#endif /*INET6*/
489
490 case IPPROTO_RSVP:
491 rsvp_print(ipds->cp, ipds->len);
492 break;
493
494 case IPPROTO_GRE:
495 /* do it */
496 gre_print(ipds->cp, ipds->len);
497 break;
498
499 case IPPROTO_MOBILE:
500 mobile_print(ipds->cp, ipds->len);
501 break;
502
503 case IPPROTO_PIM:
504 pim_print(ipds->cp, ipds->len);
505 break;
506
507 case IPPROTO_VRRP:
508 vrrp_print(ipds->cp, ipds->len, ipds->ip->ip_ttl);
509 break;
510
511 case IPPROTO_PGM:
512 pgm_print(ipds->cp, ipds->len, (const u_char *)ipds->ip);
513 break;
514
515 default:
516 if ((proto = getprotobynumber(ipds->nh)) != NULL)
517 ND_PRINT((ndo, " %s", proto->p_name));
518 else
519 ND_PRINT((ndo, " ip-proto-%d", ipds->nh));
520 ND_PRINT((ndo, " %d", ipds->len));
521 break;
522 }
523}
524
525void
526ip_print_inner(netdissect_options *ndo,
527 const u_char *bp,
528 u_int length, u_int nh,
529 const u_char *bp2)
530{
531 struct ip_print_demux_state ipd;
532
533 ipd.ip = (const struct ip *)bp2;
534 ipd.cp = bp;
535 ipd.len = length;
536 ipd.off = 0;
537 ipd.nh = nh;
538 ipd.advance = 0;
539
540 ip_print_demux(ndo, &ipd);
541}
542
543
544/*
545 * print an IP datagram.
546 */
547void
548ip_print(netdissect_options *ndo,
549 const u_char *bp,
550 u_int length)
551{
552 struct ip_print_demux_state ipd;
553 struct ip_print_demux_state *ipds=&ipd;
554 const u_char *ipend;
555 u_int hlen;
556 u_int16_t sum, ip_sum;
557 struct protoent *proto;
558
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");
564 }
565 else if (!eflag)
566 printf("IP ");
567
568 if ((u_char *)(ipds->ip + 1) > snapend) {
569 printf("[|ip]");
570 return;
571 }
572 if (length < sizeof (struct ip)) {
573 (void)printf("truncated-ip %u", length);
574 return;
575 }
576 hlen = IP_HL(ipds->ip) * 4;
577 if (hlen < sizeof (struct ip)) {
578 (void)printf("bad-hlen %u", hlen);
579 return;
580 }
581
582 ipds->len = EXTRACT_16BITS(&ipds->ip->ip_len);
583 if (length < ipds->len)
584 (void)printf("truncated-ip - %u bytes missing! ",
585 ipds->len - length);
586 if (ipds->len < hlen) {
587#ifdef GUESS_TSO
588 if (ipds->len) {
589 (void)printf("bad-len %u", ipds->len);
590 return;
591 }
592 else {
593 /* we guess that it is a TSO send */
594 ipds->len = length;
595 }
596#else
597 (void)printf("bad-len %u", ipds->len);
598 return;
599#endif /* GUESS_TSO */
600 }
601
602 /*
603 * Cut off the snapshot length to the end of the IP payload.
604 */
605 ipend = bp + ipds->len;
606 if (ipend < snapend)
607 snapend = ipend;
608
609 ipds->len -= hlen;
610
611 ipds->off = EXTRACT_16BITS(&ipds->ip->ip_off);
612
613 if (vflag) {
614 (void)printf("(tos 0x%x", (int)ipds->ip->ip_tos);
615 /* ECN bits */
616 if (ipds->ip->ip_tos & 0x03) {
617 switch (ipds->ip->ip_tos & 0x03) {
618 case 1:
619 (void)printf(",ECT(1)");
620 break;
621 case 2:
622 (void)printf(",ECT(0)");
623 break;
624 case 3:
625 (void)printf(",CE");
626 }
627 }
628
629 if (ipds->ip->ip_ttl >= 1)
630 (void)printf(", ttl %3u", ipds->ip->ip_ttl);
631
632 /*
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.
636 */
637
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),
643 ipds->ip->ip_p);
644
645 (void)printf(", length: %u", EXTRACT_16BITS(&ipds->ip->ip_len));
646
647 if ((hlen - sizeof(struct ip)) > 0) {
648 printf(", options ( ");
649 ip_optprint((u_char *)(ipds->ip + 1), hlen - sizeof(struct ip));
650 printf(" )");
651 }
652
653 if ((u_char *)ipds->ip + hlen <= snapend) {
654 sum = in_cksum((const u_short *)ipds->ip, hlen, 0);
655 if (sum != 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));
659 }
660 }
661
662 printf(") ");
663 }
664
665 /*
666 * If this is fragment zero, hand it to the next higher
667 * level protocol.
668 */
669 if ((ipds->off & 0x1fff) == 0) {
670 ipds->cp = (const u_char *)ipds->ip + hlen;
671 ipds->nh = ipds->ip->ip_p;
672
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));
678 }
679 ip_print_demux(ndo, ipds);
680 } else {
681 /* Ultra quiet now means that all this stuff should be suppressed */
682 if (qflag > 1) return;
683
684 /*
685 * if this isn't the first frag, we're missing the
686 * next level protocol header. print the ip addr
687 * and the protocol.
688 */
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);
694 else
695 (void)printf(" ip-proto-%d", ipds->ip->ip_p);
696 }
697 }
698}
699
700void
701ipN_print(register const u_char *bp, register u_int length)
702{
703 struct ip *ip, hdr;
704
705 ip = (struct ip *)bp;
706 if (length < 4) {
707 (void)printf("truncated-ip %d", length);
708 return;
709 }
710 memcpy (&hdr, (char *)ip, 4);
711 switch (IP_V(&hdr)) {
712 case 4:
713 ip_print (gndo, bp, length);
714 return;
715#ifdef INET6
716 case 6:
717 ip6_print (bp, length);
718 return;
719#endif
720 default:
721 (void)printf("unknown ip %d", IP_V(&hdr));
722 return;
723 }
724}
725
726/*
727 * Local Variables:
728 * c-style: whitesmith
729 * c-basic-offset: 8
730 * End:
731 */
732
733