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 * $FreeBSD$
22 */
23
24 #ifndef lint
25 static const char rcsid[] _U_ =
26 "@(#) $Header: /tcpdump/master/tcpdump/print-icmp.c,v 1.87 2007-09-13 17:42:31 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 <string.h>
37
38 #include "interface.h"
39 #include "addrtoname.h"
40 #include "extract.h" /* must come after interface.h */
41
42 #include "ip.h"
43 #include "udp.h"
44 #include "ipproto.h"
45 #include "mpls.h"
46
47 /*
48 * Interface Control Message Protocol Definitions.
49 * Per RFC 792, September 1981.
50 */
51
52 /*
53 * Structure of an icmp header.
54 */
55 struct icmp {
56 u_int8_t icmp_type; /* type of message, see below */
57 u_int8_t icmp_code; /* type sub code */
58 u_int16_t icmp_cksum; /* ones complement cksum of struct */
59 union {
60 u_int8_t ih_pptr; /* ICMP_PARAMPROB */
61 struct in_addr ih_gwaddr; /* ICMP_REDIRECT */
62 struct ih_idseq {
63 u_int16_t icd_id;
64 u_int16_t icd_seq;
65 } ih_idseq;
66 u_int32_t ih_void;
67 } icmp_hun;
68 #define icmp_pptr icmp_hun.ih_pptr
69 #define icmp_gwaddr icmp_hun.ih_gwaddr
70 #define icmp_id icmp_hun.ih_idseq.icd_id
71 #define icmp_seq icmp_hun.ih_idseq.icd_seq
72 #define icmp_void icmp_hun.ih_void
73 union {
74 struct id_ts {
75 u_int32_t its_otime;
76 u_int32_t its_rtime;
77 u_int32_t its_ttime;
78 } id_ts;
79 struct id_ip {
80 struct ip idi_ip;
81 /* options and then 64 bits of data */
82 } id_ip;
83 u_int32_t id_mask;
84 u_int8_t id_data[1];
85 } icmp_dun;
86 #define icmp_otime icmp_dun.id_ts.its_otime
87 #define icmp_rtime icmp_dun.id_ts.its_rtime
88 #define icmp_ttime icmp_dun.id_ts.its_ttime
89 #define icmp_ip icmp_dun.id_ip.idi_ip
90 #define icmp_mask icmp_dun.id_mask
91 #define icmp_data icmp_dun.id_data
92 };
93
94 #define ICMP_MPLS_EXT_EXTRACT_VERSION(x) (((x)&0xf0)>>4)
95 #define ICMP_MPLS_EXT_VERSION 2
96
97 /*
98 * Lower bounds on packet lengths for various types.
99 * For the error advice packets must first insure that the
100 * packet is large enought to contain the returned ip header.
101 * Only then can we do the check to see if 64 bits of packet
102 * data have been returned, since we need to check the returned
103 * ip header length.
104 */
105 #define ICMP_MINLEN 8 /* abs minimum */
106 #define ICMP_EXTD_MINLEN (156 - sizeof (struct ip)) /* draft-bonica-internet-icmp-08 */
107 #define ICMP_TSLEN (8 + 3 * sizeof (u_int32_t)) /* timestamp */
108 #define ICMP_MASKLEN 12 /* address mask */
109 #define ICMP_ADVLENMIN (8 + sizeof (struct ip) + 8) /* min */
110 #define ICMP_ADVLEN(p) (8 + (IP_HL(&(p)->icmp_ip) << 2) + 8)
111 /* N.B.: must separately check that ip_hl >= 5 */
112
113 /*
114 * Definition of type and code field values.
115 */
116 #define ICMP_ECHOREPLY 0 /* echo reply */
117 #define ICMP_UNREACH 3 /* dest unreachable, codes: */
118 #define ICMP_UNREACH_NET 0 /* bad net */
119 #define ICMP_UNREACH_HOST 1 /* bad host */
120 #define ICMP_UNREACH_PROTOCOL 2 /* bad protocol */
121 #define ICMP_UNREACH_PORT 3 /* bad port */
122 #define ICMP_UNREACH_NEEDFRAG 4 /* IP_DF caused drop */
123 #define ICMP_UNREACH_SRCFAIL 5 /* src route failed */
124 #define ICMP_UNREACH_NET_UNKNOWN 6 /* unknown net */
125 #define ICMP_UNREACH_HOST_UNKNOWN 7 /* unknown host */
126 #define ICMP_UNREACH_ISOLATED 8 /* src host isolated */
127 #define ICMP_UNREACH_NET_PROHIB 9 /* prohibited access */
128 #define ICMP_UNREACH_HOST_PROHIB 10 /* ditto */
129 #define ICMP_UNREACH_TOSNET 11 /* bad tos for net */
130 #define ICMP_UNREACH_TOSHOST 12 /* bad tos for host */
131 #define ICMP_SOURCEQUENCH 4 /* packet lost, slow down */
132 #define ICMP_REDIRECT 5 /* shorter route, codes: */
133 #define ICMP_REDIRECT_NET 0 /* for network */
134 #define ICMP_REDIRECT_HOST 1 /* for host */
135 #define ICMP_REDIRECT_TOSNET 2 /* for tos and net */
136 #define ICMP_REDIRECT_TOSHOST 3 /* for tos and host */
137 #define ICMP_ECHO 8 /* echo service */
138 #define ICMP_ROUTERADVERT 9 /* router advertisement */
139 #define ICMP_ROUTERSOLICIT 10 /* router solicitation */
140 #define ICMP_TIMXCEED 11 /* time exceeded, code: */
141 #define ICMP_TIMXCEED_INTRANS 0 /* ttl==0 in transit */
142 #define ICMP_TIMXCEED_REASS 1 /* ttl==0 in reass */
143 #define ICMP_PARAMPROB 12 /* ip header bad */
144 #define ICMP_PARAMPROB_OPTABSENT 1 /* req. opt. absent */
145 #define ICMP_TSTAMP 13 /* timestamp request */
146 #define ICMP_TSTAMPREPLY 14 /* timestamp reply */
147 #define ICMP_IREQ 15 /* information request */
148 #define ICMP_IREQREPLY 16 /* information reply */
149 #define ICMP_MASKREQ 17 /* address mask request */
150 #define ICMP_MASKREPLY 18 /* address mask reply */
151
152 #define ICMP_MAXTYPE 18
153
154 #define ICMP_INFOTYPE(type) \
155 ((type) == ICMP_ECHOREPLY || (type) == ICMP_ECHO || \
156 (type) == ICMP_ROUTERADVERT || (type) == ICMP_ROUTERSOLICIT || \
157 (type) == ICMP_TSTAMP || (type) == ICMP_TSTAMPREPLY || \
158 (type) == ICMP_IREQ || (type) == ICMP_IREQREPLY || \
159 (type) == ICMP_MASKREQ || (type) == ICMP_MASKREPLY)
160 #define ICMP_MPLS_EXT_TYPE(type) \
161 ((type) == ICMP_UNREACH || \
162 (type) == ICMP_TIMXCEED || \
163 (type) == ICMP_PARAMPROB)
164 /* rfc1700 */
165 #ifndef ICMP_UNREACH_NET_UNKNOWN
166 #define ICMP_UNREACH_NET_UNKNOWN 6 /* destination net unknown */
167 #endif
168 #ifndef ICMP_UNREACH_HOST_UNKNOWN
169 #define ICMP_UNREACH_HOST_UNKNOWN 7 /* destination host unknown */
170 #endif
171 #ifndef ICMP_UNREACH_ISOLATED
172 #define ICMP_UNREACH_ISOLATED 8 /* source host isolated */
173 #endif
174 #ifndef ICMP_UNREACH_NET_PROHIB
175 #define ICMP_UNREACH_NET_PROHIB 9 /* admin prohibited net */
176 #endif
177 #ifndef ICMP_UNREACH_HOST_PROHIB
178 #define ICMP_UNREACH_HOST_PROHIB 10 /* admin prohibited host */
179 #endif
180 #ifndef ICMP_UNREACH_TOSNET
181 #define ICMP_UNREACH_TOSNET 11 /* tos prohibited net */
182 #endif
183 #ifndef ICMP_UNREACH_TOSHOST
184 #define ICMP_UNREACH_TOSHOST 12 /* tos prohibited host */
185 #endif
186
187 /* rfc1716 */
188 #ifndef ICMP_UNREACH_FILTER_PROHIB
189 #define ICMP_UNREACH_FILTER_PROHIB 13 /* admin prohibited filter */
190 #endif
191 #ifndef ICMP_UNREACH_HOST_PRECEDENCE
192 #define ICMP_UNREACH_HOST_PRECEDENCE 14 /* host precedence violation */
193 #endif
194 #ifndef ICMP_UNREACH_PRECEDENCE_CUTOFF
195 #define ICMP_UNREACH_PRECEDENCE_CUTOFF 15 /* precedence cutoff */
196 #endif
197
198 /* Most of the icmp types */
199 static struct tok icmp2str[] = {
200 { ICMP_ECHOREPLY, "echo reply" },
201 { ICMP_SOURCEQUENCH, "source quench" },
202 { ICMP_ECHO, "echo request" },
203 { ICMP_ROUTERSOLICIT, "router solicitation" },
204 { ICMP_TSTAMP, "time stamp request" },
205 { ICMP_TSTAMPREPLY, "time stamp reply" },
206 { ICMP_IREQ, "information request" },
207 { ICMP_IREQREPLY, "information reply" },
208 { ICMP_MASKREQ, "address mask request" },
209 { 0, NULL }
210 };
211
212 /* Formats for most of the ICMP_UNREACH codes */
213 static struct tok unreach2str[] = {
214 { ICMP_UNREACH_NET, "net %s unreachable" },
215 { ICMP_UNREACH_HOST, "host %s unreachable" },
216 { ICMP_UNREACH_SRCFAIL,
217 "%s unreachable - source route failed" },
218 { ICMP_UNREACH_NET_UNKNOWN, "net %s unreachable - unknown" },
219 { ICMP_UNREACH_HOST_UNKNOWN, "host %s unreachable - unknown" },
220 { ICMP_UNREACH_ISOLATED,
221 "%s unreachable - source host isolated" },
222 { ICMP_UNREACH_NET_PROHIB,
223 "net %s unreachable - admin prohibited" },
224 { ICMP_UNREACH_HOST_PROHIB,
225 "host %s unreachable - admin prohibited" },
226 { ICMP_UNREACH_TOSNET,
227 "net %s unreachable - tos prohibited" },
228 { ICMP_UNREACH_TOSHOST,
229 "host %s unreachable - tos prohibited" },
230 { ICMP_UNREACH_FILTER_PROHIB,
231 "host %s unreachable - admin prohibited filter" },
232 { ICMP_UNREACH_HOST_PRECEDENCE,
233 "host %s unreachable - host precedence violation" },
234 { ICMP_UNREACH_PRECEDENCE_CUTOFF,
235 "host %s unreachable - precedence cutoff" },
236 { 0, NULL }
237 };
238
239 /* Formats for the ICMP_REDIRECT codes */
240 static struct tok type2str[] = {
241 { ICMP_REDIRECT_NET, "redirect %s to net %s" },
242 { ICMP_REDIRECT_HOST, "redirect %s to host %s" },
243 { ICMP_REDIRECT_TOSNET, "redirect-tos %s to net %s" },
244 { ICMP_REDIRECT_TOSHOST, "redirect-tos %s to host %s" },
245 { 0, NULL }
246 };
247
248 /* rfc1191 */
249 struct mtu_discovery {
250 u_int16_t unused;
251 u_int16_t nexthopmtu;
252 };
253
254 /* rfc1256 */
255 struct ih_rdiscovery {
256 u_int8_t ird_addrnum;
257 u_int8_t ird_addrsiz;
258 u_int16_t ird_lifetime;
259 };
260
261 struct id_rdiscovery {
262 u_int32_t ird_addr;
263 u_int32_t ird_pref;
264 };
265
266 /*
267 * draft-bonica-internet-icmp-08
268 *
269 * The Destination Unreachable, Time Exceeded
270 * and Parameter Problem messages are slighly changed as per
271 * the above draft. A new Length field gets added to give
272 * the caller an idea about the length of the piggypacked
273 * IP packet before the MPLS extension header starts.
274 *
275 * The Length field represents length of the padded "original datagram"
276 * field measured in 32-bit words.
277 *
278 * 0 1 2 3
279 * 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
280 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
281 * | Type | Code | Checksum |
282 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
283 * | unused | Length | unused |
284 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
285 * | Internet Header + leading octets of original datagram |
286 * | |
287 * | // |
288 * | |
289 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
290 */
291
292 struct icmp_ext_t {
293 u_int8_t icmp_type;
294 u_int8_t icmp_code;
295 u_int8_t icmp_checksum[2];
296 u_int8_t icmp_reserved;
297 u_int8_t icmp_length;
298 u_int8_t icmp_reserved2[2];
299 u_int8_t icmp_ext_legacy_header[128]; /* extension header starts 128 bytes after ICMP header */
300 u_int8_t icmp_ext_version_res[2];
301 u_int8_t icmp_ext_checksum[2];
302 u_int8_t icmp_ext_data[1];
303 };
304
305 struct icmp_mpls_ext_object_header_t {
306 u_int8_t length[2];
307 u_int8_t class_num;
308 u_int8_t ctype;
309 };
310
311 static const struct tok icmp_mpls_ext_obj_values[] = {
312 { 1, "MPLS Stack Entry" },
313 { 2, "Extended Payload" },
314 { 0, NULL}
315 };
316
317 /* prototypes */
318 const char *icmp_tstamp_print(u_int);
319
320 /* print the milliseconds since midnight UTC */
321 const char *
icmp_tstamp_print(u_int tstamp)322 icmp_tstamp_print(u_int tstamp) {
323 u_int msec,sec,min,hrs;
324
325 static char buf[64];
326
327 msec = tstamp % 1000;
328 sec = tstamp / 1000;
329 min = sec / 60; sec -= min * 60;
330 hrs = min / 60; min -= hrs * 60;
331 snprintf(buf, sizeof(buf), "%02u:%02u:%02u.%03u",hrs,min,sec,msec);
332 return buf;
333 }
334
335 void
icmp_print(const u_char * bp,u_int plen,const u_char * bp2,int fragmented)336 icmp_print(const u_char *bp, u_int plen, const u_char *bp2, int fragmented)
337 {
338 char *cp;
339 const struct icmp *dp;
340 const struct icmp_ext_t *ext_dp;
341 const struct ip *ip;
342 const char *str, *fmt;
343 const struct ip *oip;
344 const struct udphdr *ouh;
345 const u_int8_t *obj_tptr;
346 u_int32_t raw_label;
347 const u_char *snapend_save;
348 const struct icmp_mpls_ext_object_header_t *icmp_mpls_ext_object_header;
349 u_int hlen, dport, mtu, obj_tlen, obj_class_num, obj_ctype;
350 char buf[MAXHOSTNAMELEN + 100];
351 struct cksum_vec vec[1];
352
353 dp = (struct icmp *)bp;
354 ext_dp = (struct icmp_ext_t *)bp;
355 ip = (struct ip *)bp2;
356 str = buf;
357
358 TCHECK(dp->icmp_code);
359 switch (dp->icmp_type) {
360
361 case ICMP_ECHO:
362 case ICMP_ECHOREPLY:
363 TCHECK(dp->icmp_seq);
364 (void)snprintf(buf, sizeof(buf), "echo %s, id %u, seq %u",
365 dp->icmp_type == ICMP_ECHO ?
366 "request" : "reply",
367 EXTRACT_16BITS(&dp->icmp_id),
368 EXTRACT_16BITS(&dp->icmp_seq));
369 break;
370
371 case ICMP_UNREACH:
372 TCHECK(dp->icmp_ip.ip_dst);
373 switch (dp->icmp_code) {
374
375 case ICMP_UNREACH_PROTOCOL:
376 TCHECK(dp->icmp_ip.ip_p);
377 (void)snprintf(buf, sizeof(buf),
378 "%s protocol %d unreachable",
379 ipaddr_string(&dp->icmp_ip.ip_dst),
380 dp->icmp_ip.ip_p);
381 break;
382
383 case ICMP_UNREACH_PORT:
384 TCHECK(dp->icmp_ip.ip_p);
385 oip = &dp->icmp_ip;
386 hlen = IP_HL(oip) * 4;
387 ouh = (struct udphdr *)(((u_char *)oip) + hlen);
388 TCHECK(ouh->uh_dport);
389 dport = EXTRACT_16BITS(&ouh->uh_dport);
390 switch (oip->ip_p) {
391
392 case IPPROTO_TCP:
393 (void)snprintf(buf, sizeof(buf),
394 "%s tcp port %s unreachable",
395 ipaddr_string(&oip->ip_dst),
396 tcpport_string(dport));
397 break;
398
399 case IPPROTO_UDP:
400 (void)snprintf(buf, sizeof(buf),
401 "%s udp port %s unreachable",
402 ipaddr_string(&oip->ip_dst),
403 udpport_string(dport));
404 break;
405
406 default:
407 (void)snprintf(buf, sizeof(buf),
408 "%s protocol %d port %d unreachable",
409 ipaddr_string(&oip->ip_dst),
410 oip->ip_p, dport);
411 break;
412 }
413 break;
414
415 case ICMP_UNREACH_NEEDFRAG:
416 {
417 register const struct mtu_discovery *mp;
418 mp = (struct mtu_discovery *)(u_char *)&dp->icmp_void;
419 mtu = EXTRACT_16BITS(&mp->nexthopmtu);
420 if (mtu) {
421 (void)snprintf(buf, sizeof(buf),
422 "%s unreachable - need to frag (mtu %d)",
423 ipaddr_string(&dp->icmp_ip.ip_dst), mtu);
424 } else {
425 (void)snprintf(buf, sizeof(buf),
426 "%s unreachable - need to frag",
427 ipaddr_string(&dp->icmp_ip.ip_dst));
428 }
429 }
430 break;
431
432 default:
433 fmt = tok2str(unreach2str, "#%d %%s unreachable",
434 dp->icmp_code);
435 (void)snprintf(buf, sizeof(buf), fmt,
436 ipaddr_string(&dp->icmp_ip.ip_dst));
437 break;
438 }
439 break;
440
441 case ICMP_REDIRECT:
442 TCHECK(dp->icmp_ip.ip_dst);
443 fmt = tok2str(type2str, "redirect-#%d %%s to net %%s",
444 dp->icmp_code);
445 (void)snprintf(buf, sizeof(buf), fmt,
446 ipaddr_string(&dp->icmp_ip.ip_dst),
447 ipaddr_string(&dp->icmp_gwaddr));
448 break;
449
450 case ICMP_ROUTERADVERT:
451 {
452 register const struct ih_rdiscovery *ihp;
453 register const struct id_rdiscovery *idp;
454 u_int lifetime, num, size;
455
456 (void)snprintf(buf, sizeof(buf), "router advertisement");
457 cp = buf + strlen(buf);
458
459 ihp = (struct ih_rdiscovery *)&dp->icmp_void;
460 TCHECK(*ihp);
461 (void)strncpy(cp, " lifetime ", sizeof(buf) - (cp - buf));
462 cp = buf + strlen(buf);
463 lifetime = EXTRACT_16BITS(&ihp->ird_lifetime);
464 if (lifetime < 60) {
465 (void)snprintf(cp, sizeof(buf) - (cp - buf), "%u",
466 lifetime);
467 } else if (lifetime < 60 * 60) {
468 (void)snprintf(cp, sizeof(buf) - (cp - buf), "%u:%02u",
469 lifetime / 60, lifetime % 60);
470 } else {
471 (void)snprintf(cp, sizeof(buf) - (cp - buf),
472 "%u:%02u:%02u",
473 lifetime / 3600,
474 (lifetime % 3600) / 60,
475 lifetime % 60);
476 }
477 cp = buf + strlen(buf);
478
479 num = ihp->ird_addrnum;
480 (void)snprintf(cp, sizeof(buf) - (cp - buf), " %d:", num);
481 cp = buf + strlen(buf);
482
483 size = ihp->ird_addrsiz;
484 if (size != 2) {
485 (void)snprintf(cp, sizeof(buf) - (cp - buf),
486 " [size %d]", size);
487 break;
488 }
489 idp = (struct id_rdiscovery *)&dp->icmp_data;
490 while (num-- > 0) {
491 TCHECK(*idp);
492 (void)snprintf(cp, sizeof(buf) - (cp - buf), " {%s %u}",
493 ipaddr_string(&idp->ird_addr),
494 EXTRACT_32BITS(&idp->ird_pref));
495 cp = buf + strlen(buf);
496 ++idp;
497 }
498 }
499 break;
500
501 case ICMP_TIMXCEED:
502 TCHECK(dp->icmp_ip.ip_dst);
503 switch (dp->icmp_code) {
504
505 case ICMP_TIMXCEED_INTRANS:
506 str = "time exceeded in-transit";
507 break;
508
509 case ICMP_TIMXCEED_REASS:
510 str = "ip reassembly time exceeded";
511 break;
512
513 default:
514 (void)snprintf(buf, sizeof(buf), "time exceeded-#%d",
515 dp->icmp_code);
516 break;
517 }
518 break;
519
520 case ICMP_PARAMPROB:
521 if (dp->icmp_code)
522 (void)snprintf(buf, sizeof(buf),
523 "parameter problem - code %d", dp->icmp_code);
524 else {
525 TCHECK(dp->icmp_pptr);
526 (void)snprintf(buf, sizeof(buf),
527 "parameter problem - octet %d", dp->icmp_pptr);
528 }
529 break;
530
531 case ICMP_MASKREPLY:
532 TCHECK(dp->icmp_mask);
533 (void)snprintf(buf, sizeof(buf), "address mask is 0x%08x",
534 EXTRACT_32BITS(&dp->icmp_mask));
535 break;
536
537 case ICMP_TSTAMP:
538 TCHECK(dp->icmp_seq);
539 (void)snprintf(buf, sizeof(buf),
540 "time stamp query id %u seq %u",
541 EXTRACT_16BITS(&dp->icmp_id),
542 EXTRACT_16BITS(&dp->icmp_seq));
543 break;
544
545 case ICMP_TSTAMPREPLY:
546 TCHECK(dp->icmp_ttime);
547 (void)snprintf(buf, sizeof(buf),
548 "time stamp reply id %u seq %u: org %s",
549 EXTRACT_16BITS(&dp->icmp_id),
550 EXTRACT_16BITS(&dp->icmp_seq),
551 icmp_tstamp_print(EXTRACT_32BITS(&dp->icmp_otime)));
552
553 (void)snprintf(buf+strlen(buf),sizeof(buf)-strlen(buf),", recv %s",
554 icmp_tstamp_print(EXTRACT_32BITS(&dp->icmp_rtime)));
555 (void)snprintf(buf+strlen(buf),sizeof(buf)-strlen(buf),", xmit %s",
556 icmp_tstamp_print(EXTRACT_32BITS(&dp->icmp_ttime)));
557 break;
558
559 default:
560 str = tok2str(icmp2str, "type-#%d", dp->icmp_type);
561 break;
562 }
563 (void)printf("ICMP %s, length %u", str, plen);
564 if (vflag && !fragmented) { /* don't attempt checksumming if this is a frag */
565 u_int16_t sum, icmp_sum;
566 struct cksum_vec vec[1];
567 if (TTEST2(*bp, plen)) {
568 vec[0].ptr = (const u_int8_t *)(void *)dp;
569 vec[0].len = plen;
570 sum = in_cksum(vec, 1);
571 if (sum != 0) {
572 icmp_sum = EXTRACT_16BITS(&dp->icmp_cksum);
573 (void)printf(" (wrong icmp cksum %x (->%x)!)",
574 icmp_sum,
575 in_cksum_shouldbe(icmp_sum, sum));
576 }
577 }
578 }
579
580 /*
581 * print the remnants of the IP packet.
582 * save the snaplength as this may get overidden in the IP printer.
583 */
584 if (vflag >= 1 && !ICMP_INFOTYPE(dp->icmp_type)) {
585 bp += 8;
586 (void)printf("\n\t");
587 ip = (struct ip *)bp;
588 snaplen = snapend - bp;
589 snapend_save = snapend;
590 ip_print(gndo, bp, EXTRACT_16BITS(&ip->ip_len));
591 snapend = snapend_save;
592 }
593
594 /*
595 * Attempt to decode the MPLS extensions only for some ICMP types.
596 */
597 if (vflag >= 1 && plen > ICMP_EXTD_MINLEN && ICMP_MPLS_EXT_TYPE(dp->icmp_type)) {
598
599 TCHECK(*ext_dp);
600
601 /*
602 * Check first if the mpls extension header shows a non-zero length.
603 * If the length field is not set then silently verify the checksum
604 * to check if an extension header is present. This is expedient,
605 * however not all implementations set the length field proper.
606 */
607 if (!ext_dp->icmp_length) {
608 vec[0].ptr = (const u_int8_t *)(void *)&ext_dp->icmp_ext_version_res;
609 vec[0].len = plen - ICMP_EXTD_MINLEN;
610 if (in_cksum(vec, 1)) {
611 return;
612 }
613 }
614
615 printf("\n\tMPLS extension v%u",
616 ICMP_MPLS_EXT_EXTRACT_VERSION(*(ext_dp->icmp_ext_version_res)));
617
618 /*
619 * Sanity checking of the header.
620 */
621 if (ICMP_MPLS_EXT_EXTRACT_VERSION(*(ext_dp->icmp_ext_version_res)) !=
622 ICMP_MPLS_EXT_VERSION) {
623 printf(" packet not supported");
624 return;
625 }
626
627 hlen = plen - ICMP_EXTD_MINLEN;
628 vec[0].ptr = (const u_int8_t *)(void *)&ext_dp->icmp_ext_version_res;
629 vec[0].len = hlen;
630 printf(", checksum 0x%04x (%scorrect), length %u",
631 EXTRACT_16BITS(ext_dp->icmp_ext_checksum),
632 in_cksum(vec, 1) ? "in" : "",
633 hlen);
634
635 hlen -= 4; /* subtract common header size */
636 obj_tptr = (u_int8_t *)ext_dp->icmp_ext_data;
637
638 while (hlen > sizeof(struct icmp_mpls_ext_object_header_t)) {
639
640 icmp_mpls_ext_object_header = (struct icmp_mpls_ext_object_header_t *)obj_tptr;
641 TCHECK(*icmp_mpls_ext_object_header);
642 obj_tlen = EXTRACT_16BITS(icmp_mpls_ext_object_header->length);
643 obj_class_num = icmp_mpls_ext_object_header->class_num;
644 obj_ctype = icmp_mpls_ext_object_header->ctype;
645 obj_tptr += sizeof(struct icmp_mpls_ext_object_header_t);
646
647 printf("\n\t %s Object (%u), Class-Type: %u, length %u",
648 tok2str(icmp_mpls_ext_obj_values,"unknown",obj_class_num),
649 obj_class_num,
650 obj_ctype,
651 obj_tlen);
652
653 hlen-=sizeof(struct icmp_mpls_ext_object_header_t); /* length field includes tlv header */
654
655 /* infinite loop protection */
656 if ((obj_class_num == 0) ||
657 (obj_tlen < sizeof(struct icmp_mpls_ext_object_header_t))) {
658 return;
659 }
660 obj_tlen-=sizeof(struct icmp_mpls_ext_object_header_t);
661
662 switch (obj_class_num) {
663 case 1:
664 switch(obj_ctype) {
665 case 1:
666 TCHECK2(*obj_tptr, 4);
667 raw_label = EXTRACT_32BITS(obj_tptr);
668 printf("\n\t label %u, exp %u", MPLS_LABEL(raw_label), MPLS_EXP(raw_label));
669 if (MPLS_STACK(raw_label))
670 printf(", [S]");
671 printf(", ttl %u", MPLS_TTL(raw_label));
672 break;
673 default:
674 print_unknown_data(obj_tptr, "\n\t ", obj_tlen);
675 }
676 break;
677
678 /*
679 * FIXME those are the defined objects that lack a decoder
680 * you are welcome to contribute code ;-)
681 */
682 case 2:
683 default:
684 print_unknown_data(obj_tptr, "\n\t ", obj_tlen);
685 break;
686 }
687 if (hlen < obj_tlen)
688 break;
689 hlen -= obj_tlen;
690 obj_tptr += obj_tlen;
691 }
692 }
693
694 return;
695 trunc:
696 fputs("[|icmp]", stdout);
697 }
698