1 /*
2 * Copyright (c) 1988, 1989, 1990, 1991, 1993, 1994, 1995, 1996
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
22 #ifndef lint
23 static const char rcsid[] _U_ =
24 "@(#) $Header: /tcpdump/master/tcpdump/print-icmp.c,v 1.87 2007-09-13 17:42:31 guy Exp $ (LBL)";
25 #endif
26
27 #ifdef HAVE_CONFIG_H
28 #include "config.h"
29 #endif
30
31 #include <tcpdump-stdinc.h>
32
33 #include <stdio.h>
34 #include <string.h>
35
36 #include "interface.h"
37 #include "addrtoname.h"
38 #include "extract.h" /* must come after interface.h */
39
40 #include "ip.h"
41 #include "udp.h"
42 #include "ipproto.h"
43 #include "mpls.h"
44
45 /*
46 * Interface Control Message Protocol Definitions.
47 * Per RFC 792, September 1981.
48 */
49
50 /*
51 * Structure of an icmp header.
52 */
53 struct icmp {
54 u_int8_t icmp_type; /* type of message, see below */
55 u_int8_t icmp_code; /* type sub code */
56 u_int16_t icmp_cksum; /* ones complement cksum of struct */
57 union {
58 u_int8_t ih_pptr; /* ICMP_PARAMPROB */
59 struct in_addr ih_gwaddr; /* ICMP_REDIRECT */
60 struct ih_idseq {
61 u_int16_t icd_id;
62 u_int16_t icd_seq;
63 } ih_idseq;
64 u_int32_t ih_void;
65 } icmp_hun;
66 #define icmp_pptr icmp_hun.ih_pptr
67 #define icmp_gwaddr icmp_hun.ih_gwaddr
68 #define icmp_id icmp_hun.ih_idseq.icd_id
69 #define icmp_seq icmp_hun.ih_idseq.icd_seq
70 #define icmp_void icmp_hun.ih_void
71 union {
72 struct id_ts {
73 u_int32_t its_otime;
74 u_int32_t its_rtime;
75 u_int32_t its_ttime;
76 } id_ts;
77 struct id_ip {
78 struct ip idi_ip;
79 /* options and then 64 bits of data */
80 } id_ip;
81 u_int32_t id_mask;
82 u_int8_t id_data[1];
83 } icmp_dun;
84 #define icmp_otime icmp_dun.id_ts.its_otime
85 #define icmp_rtime icmp_dun.id_ts.its_rtime
86 #define icmp_ttime icmp_dun.id_ts.its_ttime
87 #define icmp_ip icmp_dun.id_ip.idi_ip
88 #define icmp_mask icmp_dun.id_mask
89 #define icmp_data icmp_dun.id_data
90 };
91
92 #define ICMP_MPLS_EXT_EXTRACT_VERSION(x) (((x)&0xf0)>>4)
93 #define ICMP_MPLS_EXT_VERSION 2
94
95 /*
96 * Lower bounds on packet lengths for various types.
97 * For the error advice packets must first insure that the
98 * packet is large enought to contain the returned ip header.
99 * Only then can we do the check to see if 64 bits of packet
100 * data have been returned, since we need to check the returned
101 * ip header length.
102 */
103 #define ICMP_MINLEN 8 /* abs minimum */
104 #define ICMP_EXTD_MINLEN (156 - sizeof (struct ip)) /* draft-bonica-internet-icmp-08 */
105 #define ICMP_TSLEN (8 + 3 * sizeof (u_int32_t)) /* timestamp */
106 #define ICMP_MASKLEN 12 /* address mask */
107 #define ICMP_ADVLENMIN (8 + sizeof (struct ip) + 8) /* min */
108 #define ICMP_ADVLEN(p) (8 + (IP_HL(&(p)->icmp_ip) << 2) + 8)
109 /* N.B.: must separately check that ip_hl >= 5 */
110
111 /*
112 * Definition of type and code field values.
113 */
114 #define ICMP_ECHOREPLY 0 /* echo reply */
115 #define ICMP_UNREACH 3 /* dest unreachable, codes: */
116 #define ICMP_UNREACH_NET 0 /* bad net */
117 #define ICMP_UNREACH_HOST 1 /* bad host */
118 #define ICMP_UNREACH_PROTOCOL 2 /* bad protocol */
119 #define ICMP_UNREACH_PORT 3 /* bad port */
120 #define ICMP_UNREACH_NEEDFRAG 4 /* IP_DF caused drop */
121 #define ICMP_UNREACH_SRCFAIL 5 /* src route failed */
122 #define ICMP_UNREACH_NET_UNKNOWN 6 /* unknown net */
123 #define ICMP_UNREACH_HOST_UNKNOWN 7 /* unknown host */
124 #define ICMP_UNREACH_ISOLATED 8 /* src host isolated */
125 #define ICMP_UNREACH_NET_PROHIB 9 /* prohibited access */
126 #define ICMP_UNREACH_HOST_PROHIB 10 /* ditto */
127 #define ICMP_UNREACH_TOSNET 11 /* bad tos for net */
128 #define ICMP_UNREACH_TOSHOST 12 /* bad tos for host */
129 #define ICMP_SOURCEQUENCH 4 /* packet lost, slow down */
130 #define ICMP_REDIRECT 5 /* shorter route, codes: */
131 #define ICMP_REDIRECT_NET 0 /* for network */
132 #define ICMP_REDIRECT_HOST 1 /* for host */
133 #define ICMP_REDIRECT_TOSNET 2 /* for tos and net */
134 #define ICMP_REDIRECT_TOSHOST 3 /* for tos and host */
135 #define ICMP_ECHO 8 /* echo service */
136 #define ICMP_ROUTERADVERT 9 /* router advertisement */
137 #define ICMP_ROUTERSOLICIT 10 /* router solicitation */
138 #define ICMP_TIMXCEED 11 /* time exceeded, code: */
139 #define ICMP_TIMXCEED_INTRANS 0 /* ttl==0 in transit */
140 #define ICMP_TIMXCEED_REASS 1 /* ttl==0 in reass */
141 #define ICMP_PARAMPROB 12 /* ip header bad */
142 #define ICMP_PARAMPROB_OPTABSENT 1 /* req. opt. absent */
143 #define ICMP_TSTAMP 13 /* timestamp request */
144 #define ICMP_TSTAMPREPLY 14 /* timestamp reply */
145 #define ICMP_IREQ 15 /* information request */
146 #define ICMP_IREQREPLY 16 /* information reply */
147 #define ICMP_MASKREQ 17 /* address mask request */
148 #define ICMP_MASKREPLY 18 /* address mask reply */
149
150 #define ICMP_MAXTYPE 18
151
152 #define ICMP_INFOTYPE(type) \
153 ((type) == ICMP_ECHOREPLY || (type) == ICMP_ECHO || \
154 (type) == ICMP_ROUTERADVERT || (type) == ICMP_ROUTERSOLICIT || \
155 (type) == ICMP_TSTAMP || (type) == ICMP_TSTAMPREPLY || \
156 (type) == ICMP_IREQ || (type) == ICMP_IREQREPLY || \
157 (type) == ICMP_MASKREQ || (type) == ICMP_MASKREPLY)
158 #define ICMP_MPLS_EXT_TYPE(type) \
159 ((type) == ICMP_UNREACH || \
160 (type) == ICMP_TIMXCEED || \
161 (type) == ICMP_PARAMPROB)
162 /* rfc1700 */
163 #ifndef ICMP_UNREACH_NET_UNKNOWN
164 #define ICMP_UNREACH_NET_UNKNOWN 6 /* destination net unknown */
165 #endif
166 #ifndef ICMP_UNREACH_HOST_UNKNOWN
167 #define ICMP_UNREACH_HOST_UNKNOWN 7 /* destination host unknown */
168 #endif
169 #ifndef ICMP_UNREACH_ISOLATED
170 #define ICMP_UNREACH_ISOLATED 8 /* source host isolated */
171 #endif
172 #ifndef ICMP_UNREACH_NET_PROHIB
173 #define ICMP_UNREACH_NET_PROHIB 9 /* admin prohibited net */
174 #endif
175 #ifndef ICMP_UNREACH_HOST_PROHIB
176 #define ICMP_UNREACH_HOST_PROHIB 10 /* admin prohibited host */
177 #endif
178 #ifndef ICMP_UNREACH_TOSNET
179 #define ICMP_UNREACH_TOSNET 11 /* tos prohibited net */
180 #endif
181 #ifndef ICMP_UNREACH_TOSHOST
182 #define ICMP_UNREACH_TOSHOST 12 /* tos prohibited host */
183 #endif
184
185 /* rfc1716 */
186 #ifndef ICMP_UNREACH_FILTER_PROHIB
187 #define ICMP_UNREACH_FILTER_PROHIB 13 /* admin prohibited filter */
188 #endif
189 #ifndef ICMP_UNREACH_HOST_PRECEDENCE
190 #define ICMP_UNREACH_HOST_PRECEDENCE 14 /* host precedence violation */
191 #endif
192 #ifndef ICMP_UNREACH_PRECEDENCE_CUTOFF
193 #define ICMP_UNREACH_PRECEDENCE_CUTOFF 15 /* precedence cutoff */
194 #endif
195
196 /* Most of the icmp types */
197 static const struct tok icmp2str[] = {
198 { ICMP_ECHOREPLY, "echo reply" },
199 { ICMP_SOURCEQUENCH, "source quench" },
200 { ICMP_ECHO, "echo request" },
201 { ICMP_ROUTERSOLICIT, "router solicitation" },
202 { ICMP_TSTAMP, "time stamp request" },
203 { ICMP_TSTAMPREPLY, "time stamp reply" },
204 { ICMP_IREQ, "information request" },
205 { ICMP_IREQREPLY, "information reply" },
206 { ICMP_MASKREQ, "address mask request" },
207 { 0, NULL }
208 };
209
210 /* Formats for most of the ICMP_UNREACH codes */
211 static const struct tok unreach2str[] = {
212 { ICMP_UNREACH_NET, "net %s unreachable" },
213 { ICMP_UNREACH_HOST, "host %s unreachable" },
214 { ICMP_UNREACH_SRCFAIL,
215 "%s unreachable - source route failed" },
216 { ICMP_UNREACH_NET_UNKNOWN, "net %s unreachable - unknown" },
217 { ICMP_UNREACH_HOST_UNKNOWN, "host %s unreachable - unknown" },
218 { ICMP_UNREACH_ISOLATED,
219 "%s unreachable - source host isolated" },
220 { ICMP_UNREACH_NET_PROHIB,
221 "net %s unreachable - admin prohibited" },
222 { ICMP_UNREACH_HOST_PROHIB,
223 "host %s unreachable - admin prohibited" },
224 { ICMP_UNREACH_TOSNET,
225 "net %s unreachable - tos prohibited" },
226 { ICMP_UNREACH_TOSHOST,
227 "host %s unreachable - tos prohibited" },
228 { ICMP_UNREACH_FILTER_PROHIB,
229 "host %s unreachable - admin prohibited filter" },
230 { ICMP_UNREACH_HOST_PRECEDENCE,
231 "host %s unreachable - host precedence violation" },
232 { ICMP_UNREACH_PRECEDENCE_CUTOFF,
233 "host %s unreachable - precedence cutoff" },
234 { 0, NULL }
235 };
236
237 /* Formats for the ICMP_REDIRECT codes */
238 static const struct tok type2str[] = {
239 { ICMP_REDIRECT_NET, "redirect %s to net %s" },
240 { ICMP_REDIRECT_HOST, "redirect %s to host %s" },
241 { ICMP_REDIRECT_TOSNET, "redirect-tos %s to net %s" },
242 { ICMP_REDIRECT_TOSHOST, "redirect-tos %s to host %s" },
243 { 0, NULL }
244 };
245
246 /* rfc1191 */
247 struct mtu_discovery {
248 u_int16_t unused;
249 u_int16_t nexthopmtu;
250 };
251
252 /* rfc1256 */
253 struct ih_rdiscovery {
254 u_int8_t ird_addrnum;
255 u_int8_t ird_addrsiz;
256 u_int16_t ird_lifetime;
257 };
258
259 struct id_rdiscovery {
260 u_int32_t ird_addr;
261 u_int32_t ird_pref;
262 };
263
264 /*
265 * draft-bonica-internet-icmp-08
266 *
267 * The Destination Unreachable, Time Exceeded
268 * and Parameter Problem messages are slighly changed as per
269 * the above draft. A new Length field gets added to give
270 * the caller an idea about the length of the piggypacked
271 * IP packet before the MPLS extension header starts.
272 *
273 * The Length field represents length of the padded "original datagram"
274 * field measured in 32-bit words.
275 *
276 * 0 1 2 3
277 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
278 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
279 * | Type | Code | Checksum |
280 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
281 * | unused | Length | unused |
282 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
283 * | Internet Header + leading octets of original datagram |
284 * | |
285 * | // |
286 * | |
287 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
288 */
289
290 struct icmp_ext_t {
291 u_int8_t icmp_type;
292 u_int8_t icmp_code;
293 u_int8_t icmp_checksum[2];
294 u_int8_t icmp_reserved;
295 u_int8_t icmp_length;
296 u_int8_t icmp_reserved2[2];
297 u_int8_t icmp_ext_legacy_header[128]; /* extension header starts 128 bytes after ICMP header */
298 u_int8_t icmp_ext_version_res[2];
299 u_int8_t icmp_ext_checksum[2];
300 u_int8_t icmp_ext_data[1];
301 };
302
303 struct icmp_mpls_ext_object_header_t {
304 u_int8_t length[2];
305 u_int8_t class_num;
306 u_int8_t ctype;
307 };
308
309 static const struct tok icmp_mpls_ext_obj_values[] = {
310 { 1, "MPLS Stack Entry" },
311 { 2, "Extended Payload" },
312 { 0, NULL}
313 };
314
315 /* prototypes */
316 const char *icmp_tstamp_print(u_int);
317
318 /* print the milliseconds since midnight UTC */
319 const char *
icmp_tstamp_print(u_int tstamp)320 icmp_tstamp_print(u_int tstamp) {
321 u_int msec,sec,min,hrs;
322
323 static char buf[64];
324
325 msec = tstamp % 1000;
326 sec = tstamp / 1000;
327 min = sec / 60; sec -= min * 60;
328 hrs = min / 60; min -= hrs * 60;
329 snprintf(buf, sizeof(buf), "%02u:%02u:%02u.%03u",hrs,min,sec,msec);
330 return buf;
331 }
332
333 void
icmp_print(const u_char * bp,u_int plen,const u_char * bp2,int fragmented)334 icmp_print(const u_char *bp, u_int plen, const u_char *bp2, int fragmented)
335 {
336 char *cp;
337 const struct icmp *dp;
338 const struct icmp_ext_t *ext_dp;
339 const struct ip *ip;
340 const char *str, *fmt;
341 const struct ip *oip;
342 const struct udphdr *ouh;
343 const u_int8_t *obj_tptr;
344 u_int32_t raw_label;
345 const u_char *snapend_save;
346 const struct icmp_mpls_ext_object_header_t *icmp_mpls_ext_object_header;
347 u_int hlen, dport, mtu, obj_tlen, obj_class_num, obj_ctype;
348 char buf[MAXHOSTNAMELEN + 100];
349 struct cksum_vec vec[1];
350
351 dp = (struct icmp *)bp;
352 ext_dp = (struct icmp_ext_t *)bp;
353 ip = (struct ip *)bp2;
354 str = buf;
355
356 TCHECK(dp->icmp_code);
357 switch (dp->icmp_type) {
358
359 case ICMP_ECHO:
360 case ICMP_ECHOREPLY:
361 TCHECK(dp->icmp_seq);
362 (void)snprintf(buf, sizeof(buf), "echo %s, id %u, seq %u",
363 dp->icmp_type == ICMP_ECHO ?
364 "request" : "reply",
365 EXTRACT_16BITS(&dp->icmp_id),
366 EXTRACT_16BITS(&dp->icmp_seq));
367 break;
368
369 case ICMP_UNREACH:
370 TCHECK(dp->icmp_ip.ip_dst);
371 switch (dp->icmp_code) {
372
373 case ICMP_UNREACH_PROTOCOL:
374 TCHECK(dp->icmp_ip.ip_p);
375 (void)snprintf(buf, sizeof(buf),
376 "%s protocol %d unreachable",
377 ipaddr_string(&dp->icmp_ip.ip_dst),
378 dp->icmp_ip.ip_p);
379 break;
380
381 case ICMP_UNREACH_PORT:
382 TCHECK(dp->icmp_ip.ip_p);
383 oip = &dp->icmp_ip;
384 hlen = IP_HL(oip) * 4;
385 ouh = (struct udphdr *)(((u_char *)oip) + hlen);
386 TCHECK(ouh->uh_dport);
387 dport = EXTRACT_16BITS(&ouh->uh_dport);
388 switch (oip->ip_p) {
389
390 case IPPROTO_TCP:
391 (void)snprintf(buf, sizeof(buf),
392 "%s tcp port %s unreachable",
393 ipaddr_string(&oip->ip_dst),
394 tcpport_string(dport));
395 break;
396
397 case IPPROTO_UDP:
398 (void)snprintf(buf, sizeof(buf),
399 "%s udp port %s unreachable",
400 ipaddr_string(&oip->ip_dst),
401 udpport_string(dport));
402 break;
403
404 default:
405 (void)snprintf(buf, sizeof(buf),
406 "%s protocol %d port %d unreachable",
407 ipaddr_string(&oip->ip_dst),
408 oip->ip_p, dport);
409 break;
410 }
411 break;
412
413 case ICMP_UNREACH_NEEDFRAG:
414 {
415 register const struct mtu_discovery *mp;
416 mp = (struct mtu_discovery *)(u_char *)&dp->icmp_void;
417 mtu = EXTRACT_16BITS(&mp->nexthopmtu);
418 if (mtu) {
419 (void)snprintf(buf, sizeof(buf),
420 "%s unreachable - need to frag (mtu %d)",
421 ipaddr_string(&dp->icmp_ip.ip_dst), mtu);
422 } else {
423 (void)snprintf(buf, sizeof(buf),
424 "%s unreachable - need to frag",
425 ipaddr_string(&dp->icmp_ip.ip_dst));
426 }
427 }
428 break;
429
430 default:
431 fmt = tok2str(unreach2str, "#%d %%s unreachable",
432 dp->icmp_code);
433 (void)snprintf(buf, sizeof(buf), fmt,
434 ipaddr_string(&dp->icmp_ip.ip_dst));
435 break;
436 }
437 break;
438
439 case ICMP_REDIRECT:
440 TCHECK(dp->icmp_ip.ip_dst);
441 fmt = tok2str(type2str, "redirect-#%d %%s to net %%s",
442 dp->icmp_code);
443 (void)snprintf(buf, sizeof(buf), fmt,
444 ipaddr_string(&dp->icmp_ip.ip_dst),
445 ipaddr_string(&dp->icmp_gwaddr));
446 break;
447
448 case ICMP_ROUTERADVERT:
449 {
450 register const struct ih_rdiscovery *ihp;
451 register const struct id_rdiscovery *idp;
452 u_int lifetime, num, size;
453
454 (void)snprintf(buf, sizeof(buf), "router advertisement");
455 cp = buf + strlen(buf);
456
457 ihp = (struct ih_rdiscovery *)&dp->icmp_void;
458 TCHECK(*ihp);
459 (void)strncpy(cp, " lifetime ", sizeof(buf) - (cp - buf));
460 cp = buf + strlen(buf);
461 lifetime = EXTRACT_16BITS(&ihp->ird_lifetime);
462 if (lifetime < 60) {
463 (void)snprintf(cp, sizeof(buf) - (cp - buf), "%u",
464 lifetime);
465 } else if (lifetime < 60 * 60) {
466 (void)snprintf(cp, sizeof(buf) - (cp - buf), "%u:%02u",
467 lifetime / 60, lifetime % 60);
468 } else {
469 (void)snprintf(cp, sizeof(buf) - (cp - buf),
470 "%u:%02u:%02u",
471 lifetime / 3600,
472 (lifetime % 3600) / 60,
473 lifetime % 60);
474 }
475 cp = buf + strlen(buf);
476
477 num = ihp->ird_addrnum;
478 (void)snprintf(cp, sizeof(buf) - (cp - buf), " %d:", num);
479 cp = buf + strlen(buf);
480
481 size = ihp->ird_addrsiz;
482 if (size != 2) {
483 (void)snprintf(cp, sizeof(buf) - (cp - buf),
484 " [size %d]", size);
485 break;
486 }
487 idp = (struct id_rdiscovery *)&dp->icmp_data;
488 while (num-- > 0) {
489 TCHECK(*idp);
490 (void)snprintf(cp, sizeof(buf) - (cp - buf), " {%s %u}",
491 ipaddr_string(&idp->ird_addr),
492 EXTRACT_32BITS(&idp->ird_pref));
493 cp = buf + strlen(buf);
494 ++idp;
495 }
496 }
497 break;
498
499 case ICMP_TIMXCEED:
500 TCHECK(dp->icmp_ip.ip_dst);
501 switch (dp->icmp_code) {
502
503 case ICMP_TIMXCEED_INTRANS:
504 str = "time exceeded in-transit";
505 break;
506
507 case ICMP_TIMXCEED_REASS:
508 str = "ip reassembly time exceeded";
509 break;
510
511 default:
512 (void)snprintf(buf, sizeof(buf), "time exceeded-#%d",
513 dp->icmp_code);
514 break;
515 }
516 break;
517
518 case ICMP_PARAMPROB:
519 if (dp->icmp_code)
520 (void)snprintf(buf, sizeof(buf),
521 "parameter problem - code %d", dp->icmp_code);
522 else {
523 TCHECK(dp->icmp_pptr);
524 (void)snprintf(buf, sizeof(buf),
525 "parameter problem - octet %d", dp->icmp_pptr);
526 }
527 break;
528
529 case ICMP_MASKREPLY:
530 TCHECK(dp->icmp_mask);
531 (void)snprintf(buf, sizeof(buf), "address mask is 0x%08x",
532 EXTRACT_32BITS(&dp->icmp_mask));
533 break;
534
535 case ICMP_TSTAMP:
536 TCHECK(dp->icmp_seq);
537 (void)snprintf(buf, sizeof(buf),
538 "time stamp query id %u seq %u",
539 EXTRACT_16BITS(&dp->icmp_id),
540 EXTRACT_16BITS(&dp->icmp_seq));
541 break;
542
543 case ICMP_TSTAMPREPLY:
544 TCHECK(dp->icmp_ttime);
545 (void)snprintf(buf, sizeof(buf),
546 "time stamp reply id %u seq %u: org %s",
547 EXTRACT_16BITS(&dp->icmp_id),
548 EXTRACT_16BITS(&dp->icmp_seq),
549 icmp_tstamp_print(EXTRACT_32BITS(&dp->icmp_otime)));
550
551 (void)snprintf(buf+strlen(buf),sizeof(buf)-strlen(buf),", recv %s",
552 icmp_tstamp_print(EXTRACT_32BITS(&dp->icmp_rtime)));
553 (void)snprintf(buf+strlen(buf),sizeof(buf)-strlen(buf),", xmit %s",
554 icmp_tstamp_print(EXTRACT_32BITS(&dp->icmp_ttime)));
555 break;
556
557 default:
558 str = tok2str(icmp2str, "type-#%d", dp->icmp_type);
559 break;
560 }
561 (void)printf("ICMP %s, length %u", str, plen);
562 if (vflag && !fragmented) { /* don't attempt checksumming if this is a frag */
563 u_int16_t sum, icmp_sum;
564 struct cksum_vec vec[1];
565 if (TTEST2(*bp, plen)) {
566 vec[0].ptr = (const u_int8_t *)(void *)dp;
567 vec[0].len = plen;
568 sum = in_cksum(vec, 1);
569 if (sum != 0) {
570 icmp_sum = EXTRACT_16BITS(&dp->icmp_cksum);
571 (void)printf(" (wrong icmp cksum %x (->%x)!)",
572 icmp_sum,
573 in_cksum_shouldbe(icmp_sum, sum));
574 }
575 }
576 }
577
578 /*
579 * print the remnants of the IP packet.
580 * save the snaplength as this may get overidden in the IP printer.
581 */
582 if (vflag >= 1 && !ICMP_INFOTYPE(dp->icmp_type)) {
583 bp += 8;
584 (void)printf("\n\t");
585 ip = (struct ip *)bp;
586 snaplen = snapend - bp;
587 snapend_save = snapend;
588 ip_print(gndo, bp, EXTRACT_16BITS(&ip->ip_len));
589 snapend = snapend_save;
590 }
591
592 /*
593 * Attempt to decode the MPLS extensions only for some ICMP types.
594 */
595 if (vflag >= 1 && plen > ICMP_EXTD_MINLEN && ICMP_MPLS_EXT_TYPE(dp->icmp_type)) {
596
597 TCHECK(*ext_dp);
598
599 /*
600 * Check first if the mpls extension header shows a non-zero length.
601 * If the length field is not set then silently verify the checksum
602 * to check if an extension header is present. This is expedient,
603 * however not all implementations set the length field proper.
604 */
605 if (!ext_dp->icmp_length) {
606 vec[0].ptr = (const u_int8_t *)(void *)&ext_dp->icmp_ext_version_res;
607 vec[0].len = plen - ICMP_EXTD_MINLEN;
608 if (in_cksum(vec, 1)) {
609 return;
610 }
611 }
612
613 printf("\n\tMPLS extension v%u",
614 ICMP_MPLS_EXT_EXTRACT_VERSION(*(ext_dp->icmp_ext_version_res)));
615
616 /*
617 * Sanity checking of the header.
618 */
619 if (ICMP_MPLS_EXT_EXTRACT_VERSION(*(ext_dp->icmp_ext_version_res)) !=
620 ICMP_MPLS_EXT_VERSION) {
621 printf(" packet not supported");
622 return;
623 }
624
625 hlen = plen - ICMP_EXTD_MINLEN;
626 vec[0].ptr = (const u_int8_t *)(void *)&ext_dp->icmp_ext_version_res;
627 vec[0].len = hlen;
628 printf(", checksum 0x%04x (%scorrect), length %u",
629 EXTRACT_16BITS(ext_dp->icmp_ext_checksum),
630 in_cksum(vec, 1) ? "in" : "",
631 hlen);
632
633 hlen -= 4; /* subtract common header size */
634 obj_tptr = (u_int8_t *)ext_dp->icmp_ext_data;
635
636 while (hlen > sizeof(struct icmp_mpls_ext_object_header_t)) {
637
638 icmp_mpls_ext_object_header = (struct icmp_mpls_ext_object_header_t *)obj_tptr;
639 TCHECK(*icmp_mpls_ext_object_header);
640 obj_tlen = EXTRACT_16BITS(icmp_mpls_ext_object_header->length);
641 obj_class_num = icmp_mpls_ext_object_header->class_num;
642 obj_ctype = icmp_mpls_ext_object_header->ctype;
643 obj_tptr += sizeof(struct icmp_mpls_ext_object_header_t);
644
645 printf("\n\t %s Object (%u), Class-Type: %u, length %u",
646 tok2str(icmp_mpls_ext_obj_values,"unknown",obj_class_num),
647 obj_class_num,
648 obj_ctype,
649 obj_tlen);
650
651 hlen-=sizeof(struct icmp_mpls_ext_object_header_t); /* length field includes tlv header */
652
653 /* infinite loop protection */
654 if ((obj_class_num == 0) ||
655 (obj_tlen < sizeof(struct icmp_mpls_ext_object_header_t))) {
656 return;
657 }
658 obj_tlen-=sizeof(struct icmp_mpls_ext_object_header_t);
659
660 switch (obj_class_num) {
661 case 1:
662 switch(obj_ctype) {
663 case 1:
664 TCHECK2(*obj_tptr, 4);
665 raw_label = EXTRACT_32BITS(obj_tptr);
666 printf("\n\t label %u, exp %u", MPLS_LABEL(raw_label), MPLS_EXP(raw_label));
667 if (MPLS_STACK(raw_label))
668 printf(", [S]");
669 printf(", ttl %u", MPLS_TTL(raw_label));
670 break;
671 default:
672 print_unknown_data(obj_tptr, "\n\t ", obj_tlen);
673 }
674 break;
675
676 /*
677 * FIXME those are the defined objects that lack a decoder
678 * you are welcome to contribute code ;-)
679 */
680 case 2:
681 default:
682 print_unknown_data(obj_tptr, "\n\t ", obj_tlen);
683 break;
684 }
685 if (hlen < obj_tlen)
686 break;
687 hlen -= obj_tlen;
688 obj_tptr += obj_tlen;
689 }
690 }
691
692 return;
693 trunc:
694 fputs("[|icmp]", stdout);
695 }
696