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[tcpdump] / print-icmp.c
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 #define NETDISSECT_REWORKED
23 #ifdef HAVE_CONFIG_H
24 #include "config.h"
25 #endif
26
27 #include <tcpdump-stdinc.h>
28
29 #include <stdio.h>
30 #include <string.h>
31
32 #include "interface.h"
33 #include "addrtoname.h"
34 #include "extract.h" /* must come after interface.h */
35
36 #include "ip.h"
37 #include "udp.h"
38 #include "ipproto.h"
39 #include "mpls.h"
40
41 /*
42 * Interface Control Message Protocol Definitions.
43 * Per RFC 792, September 1981.
44 */
45
46 /*
47 * Structure of an icmp header.
48 */
49 struct icmp {
50 u_int8_t icmp_type; /* type of message, see below */
51 u_int8_t icmp_code; /* type sub code */
52 u_int16_t icmp_cksum; /* ones complement cksum of struct */
53 union {
54 u_int8_t ih_pptr; /* ICMP_PARAMPROB */
55 struct in_addr ih_gwaddr; /* ICMP_REDIRECT */
56 struct ih_idseq {
57 u_int16_t icd_id;
58 u_int16_t icd_seq;
59 } ih_idseq;
60 u_int32_t ih_void;
61 } icmp_hun;
62 #define icmp_pptr icmp_hun.ih_pptr
63 #define icmp_gwaddr icmp_hun.ih_gwaddr
64 #define icmp_id icmp_hun.ih_idseq.icd_id
65 #define icmp_seq icmp_hun.ih_idseq.icd_seq
66 #define icmp_void icmp_hun.ih_void
67 union {
68 struct id_ts {
69 u_int32_t its_otime;
70 u_int32_t its_rtime;
71 u_int32_t its_ttime;
72 } id_ts;
73 struct id_ip {
74 struct ip idi_ip;
75 /* options and then 64 bits of data */
76 } id_ip;
77 u_int32_t id_mask;
78 u_int8_t id_data[1];
79 } icmp_dun;
80 #define icmp_otime icmp_dun.id_ts.its_otime
81 #define icmp_rtime icmp_dun.id_ts.its_rtime
82 #define icmp_ttime icmp_dun.id_ts.its_ttime
83 #define icmp_ip icmp_dun.id_ip.idi_ip
84 #define icmp_mask icmp_dun.id_mask
85 #define icmp_data icmp_dun.id_data
86 };
87
88 #define ICMP_MPLS_EXT_EXTRACT_VERSION(x) (((x)&0xf0)>>4)
89 #define ICMP_MPLS_EXT_VERSION 2
90
91 /*
92 * Lower bounds on packet lengths for various types.
93 * For the error advice packets must first insure that the
94 * packet is large enought to contain the returned ip header.
95 * Only then can we do the check to see if 64 bits of packet
96 * data have been returned, since we need to check the returned
97 * ip header length.
98 */
99 #define ICMP_MINLEN 8 /* abs minimum */
100 #define ICMP_EXTD_MINLEN (156 - sizeof (struct ip)) /* draft-bonica-internet-icmp-08 */
101 #define ICMP_TSLEN (8 + 3 * sizeof (u_int32_t)) /* timestamp */
102 #define ICMP_MASKLEN 12 /* address mask */
103 #define ICMP_ADVLENMIN (8 + sizeof (struct ip) + 8) /* min */
104 #define ICMP_ADVLEN(p) (8 + (IP_HL(&(p)->icmp_ip) << 2) + 8)
105 /* N.B.: must separately check that ip_hl >= 5 */
106
107 /*
108 * Definition of type and code field values.
109 */
110 #define ICMP_ECHOREPLY 0 /* echo reply */
111 #define ICMP_UNREACH 3 /* dest unreachable, codes: */
112 #define ICMP_UNREACH_NET 0 /* bad net */
113 #define ICMP_UNREACH_HOST 1 /* bad host */
114 #define ICMP_UNREACH_PROTOCOL 2 /* bad protocol */
115 #define ICMP_UNREACH_PORT 3 /* bad port */
116 #define ICMP_UNREACH_NEEDFRAG 4 /* IP_DF caused drop */
117 #define ICMP_UNREACH_SRCFAIL 5 /* src route failed */
118 #define ICMP_UNREACH_NET_UNKNOWN 6 /* unknown net */
119 #define ICMP_UNREACH_HOST_UNKNOWN 7 /* unknown host */
120 #define ICMP_UNREACH_ISOLATED 8 /* src host isolated */
121 #define ICMP_UNREACH_NET_PROHIB 9 /* prohibited access */
122 #define ICMP_UNREACH_HOST_PROHIB 10 /* ditto */
123 #define ICMP_UNREACH_TOSNET 11 /* bad tos for net */
124 #define ICMP_UNREACH_TOSHOST 12 /* bad tos for host */
125 #define ICMP_SOURCEQUENCH 4 /* packet lost, slow down */
126 #define ICMP_REDIRECT 5 /* shorter route, codes: */
127 #define ICMP_REDIRECT_NET 0 /* for network */
128 #define ICMP_REDIRECT_HOST 1 /* for host */
129 #define ICMP_REDIRECT_TOSNET 2 /* for tos and net */
130 #define ICMP_REDIRECT_TOSHOST 3 /* for tos and host */
131 #define ICMP_ECHO 8 /* echo service */
132 #define ICMP_ROUTERADVERT 9 /* router advertisement */
133 #define ICMP_ROUTERSOLICIT 10 /* router solicitation */
134 #define ICMP_TIMXCEED 11 /* time exceeded, code: */
135 #define ICMP_TIMXCEED_INTRANS 0 /* ttl==0 in transit */
136 #define ICMP_TIMXCEED_REASS 1 /* ttl==0 in reass */
137 #define ICMP_PARAMPROB 12 /* ip header bad */
138 #define ICMP_PARAMPROB_OPTABSENT 1 /* req. opt. absent */
139 #define ICMP_TSTAMP 13 /* timestamp request */
140 #define ICMP_TSTAMPREPLY 14 /* timestamp reply */
141 #define ICMP_IREQ 15 /* information request */
142 #define ICMP_IREQREPLY 16 /* information reply */
143 #define ICMP_MASKREQ 17 /* address mask request */
144 #define ICMP_MASKREPLY 18 /* address mask reply */
145
146 #define ICMP_MAXTYPE 18
147
148 #define ICMP_INFOTYPE(type) \
149 ((type) == ICMP_ECHOREPLY || (type) == ICMP_ECHO || \
150 (type) == ICMP_ROUTERADVERT || (type) == ICMP_ROUTERSOLICIT || \
151 (type) == ICMP_TSTAMP || (type) == ICMP_TSTAMPREPLY || \
152 (type) == ICMP_IREQ || (type) == ICMP_IREQREPLY || \
153 (type) == ICMP_MASKREQ || (type) == ICMP_MASKREPLY)
154 #define ICMP_MPLS_EXT_TYPE(type) \
155 ((type) == ICMP_UNREACH || \
156 (type) == ICMP_TIMXCEED || \
157 (type) == ICMP_PARAMPROB)
158 /* rfc1700 */
159 #ifndef ICMP_UNREACH_NET_UNKNOWN
160 #define ICMP_UNREACH_NET_UNKNOWN 6 /* destination net unknown */
161 #endif
162 #ifndef ICMP_UNREACH_HOST_UNKNOWN
163 #define ICMP_UNREACH_HOST_UNKNOWN 7 /* destination host unknown */
164 #endif
165 #ifndef ICMP_UNREACH_ISOLATED
166 #define ICMP_UNREACH_ISOLATED 8 /* source host isolated */
167 #endif
168 #ifndef ICMP_UNREACH_NET_PROHIB
169 #define ICMP_UNREACH_NET_PROHIB 9 /* admin prohibited net */
170 #endif
171 #ifndef ICMP_UNREACH_HOST_PROHIB
172 #define ICMP_UNREACH_HOST_PROHIB 10 /* admin prohibited host */
173 #endif
174 #ifndef ICMP_UNREACH_TOSNET
175 #define ICMP_UNREACH_TOSNET 11 /* tos prohibited net */
176 #endif
177 #ifndef ICMP_UNREACH_TOSHOST
178 #define ICMP_UNREACH_TOSHOST 12 /* tos prohibited host */
179 #endif
180
181 /* rfc1716 */
182 #ifndef ICMP_UNREACH_FILTER_PROHIB
183 #define ICMP_UNREACH_FILTER_PROHIB 13 /* admin prohibited filter */
184 #endif
185 #ifndef ICMP_UNREACH_HOST_PRECEDENCE
186 #define ICMP_UNREACH_HOST_PRECEDENCE 14 /* host precedence violation */
187 #endif
188 #ifndef ICMP_UNREACH_PRECEDENCE_CUTOFF
189 #define ICMP_UNREACH_PRECEDENCE_CUTOFF 15 /* precedence cutoff */
190 #endif
191
192 /* Most of the icmp types */
193 static const struct tok icmp2str[] = {
194 { ICMP_ECHOREPLY, "echo reply" },
195 { ICMP_SOURCEQUENCH, "source quench" },
196 { ICMP_ECHO, "echo request" },
197 { ICMP_ROUTERSOLICIT, "router solicitation" },
198 { ICMP_TSTAMP, "time stamp request" },
199 { ICMP_TSTAMPREPLY, "time stamp reply" },
200 { ICMP_IREQ, "information request" },
201 { ICMP_IREQREPLY, "information reply" },
202 { ICMP_MASKREQ, "address mask request" },
203 { 0, NULL }
204 };
205
206 /* Formats for most of the ICMP_UNREACH codes */
207 static const struct tok unreach2str[] = {
208 { ICMP_UNREACH_NET, "net %s unreachable" },
209 { ICMP_UNREACH_HOST, "host %s unreachable" },
210 { ICMP_UNREACH_SRCFAIL,
211 "%s unreachable - source route failed" },
212 { ICMP_UNREACH_NET_UNKNOWN, "net %s unreachable - unknown" },
213 { ICMP_UNREACH_HOST_UNKNOWN, "host %s unreachable - unknown" },
214 { ICMP_UNREACH_ISOLATED,
215 "%s unreachable - source host isolated" },
216 { ICMP_UNREACH_NET_PROHIB,
217 "net %s unreachable - admin prohibited" },
218 { ICMP_UNREACH_HOST_PROHIB,
219 "host %s unreachable - admin prohibited" },
220 { ICMP_UNREACH_TOSNET,
221 "net %s unreachable - tos prohibited" },
222 { ICMP_UNREACH_TOSHOST,
223 "host %s unreachable - tos prohibited" },
224 { ICMP_UNREACH_FILTER_PROHIB,
225 "host %s unreachable - admin prohibited filter" },
226 { ICMP_UNREACH_HOST_PRECEDENCE,
227 "host %s unreachable - host precedence violation" },
228 { ICMP_UNREACH_PRECEDENCE_CUTOFF,
229 "host %s unreachable - precedence cutoff" },
230 { 0, NULL }
231 };
232
233 /* Formats for the ICMP_REDIRECT codes */
234 static const struct tok type2str[] = {
235 { ICMP_REDIRECT_NET, "redirect %s to net %s" },
236 { ICMP_REDIRECT_HOST, "redirect %s to host %s" },
237 { ICMP_REDIRECT_TOSNET, "redirect-tos %s to net %s" },
238 { ICMP_REDIRECT_TOSHOST, "redirect-tos %s to host %s" },
239 { 0, NULL }
240 };
241
242 /* rfc1191 */
243 struct mtu_discovery {
244 u_int16_t unused;
245 u_int16_t nexthopmtu;
246 };
247
248 /* rfc1256 */
249 struct ih_rdiscovery {
250 u_int8_t ird_addrnum;
251 u_int8_t ird_addrsiz;
252 u_int16_t ird_lifetime;
253 };
254
255 struct id_rdiscovery {
256 u_int32_t ird_addr;
257 u_int32_t ird_pref;
258 };
259
260 /*
261 * draft-bonica-internet-icmp-08
262 *
263 * The Destination Unreachable, Time Exceeded
264 * and Parameter Problem messages are slighly changed as per
265 * the above draft. A new Length field gets added to give
266 * the caller an idea about the length of the piggypacked
267 * IP packet before the MPLS extension header starts.
268 *
269 * The Length field represents length of the padded "original datagram"
270 * field measured in 32-bit words.
271 *
272 * 0 1 2 3
273 * 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
274 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
275 * | Type | Code | Checksum |
276 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
277 * | unused | Length | unused |
278 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
279 * | Internet Header + leading octets of original datagram |
280 * | |
281 * | // |
282 * | |
283 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
284 */
285
286 struct icmp_ext_t {
287 u_int8_t icmp_type;
288 u_int8_t icmp_code;
289 u_int8_t icmp_checksum[2];
290 u_int8_t icmp_reserved;
291 u_int8_t icmp_length;
292 u_int8_t icmp_reserved2[2];
293 u_int8_t icmp_ext_legacy_header[128]; /* extension header starts 128 bytes after ICMP header */
294 u_int8_t icmp_ext_version_res[2];
295 u_int8_t icmp_ext_checksum[2];
296 u_int8_t icmp_ext_data[1];
297 };
298
299 struct icmp_mpls_ext_object_header_t {
300 u_int8_t length[2];
301 u_int8_t class_num;
302 u_int8_t ctype;
303 };
304
305 static const struct tok icmp_mpls_ext_obj_values[] = {
306 { 1, "MPLS Stack Entry" },
307 { 2, "Extended Payload" },
308 { 0, NULL}
309 };
310
311 /* prototypes */
312 const char *icmp_tstamp_print(u_int);
313
314 /* print the milliseconds since midnight UTC */
315 const char *
316 icmp_tstamp_print(u_int tstamp) {
317 u_int msec,sec,min,hrs;
318
319 static char buf[64];
320
321 msec = tstamp % 1000;
322 sec = tstamp / 1000;
323 min = sec / 60; sec -= min * 60;
324 hrs = min / 60; min -= hrs * 60;
325 snprintf(buf, sizeof(buf), "%02u:%02u:%02u.%03u",hrs,min,sec,msec);
326 return buf;
327 }
328
329 void
330 icmp_print(netdissect_options *ndo, const u_char *bp, u_int plen, const u_char *bp2,
331 int fragmented)
332 {
333 char *cp;
334 const struct icmp *dp;
335 const struct icmp_ext_t *ext_dp;
336 const struct ip *ip;
337 const char *str, *fmt;
338 const struct ip *oip;
339 const struct udphdr *ouh;
340 const u_int8_t *obj_tptr;
341 u_int32_t raw_label;
342 const u_char *snapend_save;
343 const struct icmp_mpls_ext_object_header_t *icmp_mpls_ext_object_header;
344 u_int hlen, dport, mtu, obj_tlen, obj_class_num, obj_ctype;
345 char buf[MAXHOSTNAMELEN + 100];
346 struct cksum_vec vec[1];
347
348 dp = (struct icmp *)bp;
349 ext_dp = (struct icmp_ext_t *)bp;
350 ip = (struct ip *)bp2;
351 str = buf;
352
353 ND_TCHECK(dp->icmp_code);
354 switch (dp->icmp_type) {
355
356 case ICMP_ECHO:
357 case ICMP_ECHOREPLY:
358 ND_TCHECK(dp->icmp_seq);
359 (void)snprintf(buf, sizeof(buf), "echo %s, id %u, seq %u",
360 dp->icmp_type == ICMP_ECHO ?
361 "request" : "reply",
362 EXTRACT_16BITS(&dp->icmp_id),
363 EXTRACT_16BITS(&dp->icmp_seq));
364 break;
365
366 case ICMP_UNREACH:
367 ND_TCHECK(dp->icmp_ip.ip_dst);
368 switch (dp->icmp_code) {
369
370 case ICMP_UNREACH_PROTOCOL:
371 ND_TCHECK(dp->icmp_ip.ip_p);
372 (void)snprintf(buf, sizeof(buf),
373 "%s protocol %d unreachable",
374 ipaddr_string(&dp->icmp_ip.ip_dst),
375 dp->icmp_ip.ip_p);
376 break;
377
378 case ICMP_UNREACH_PORT:
379 ND_TCHECK(dp->icmp_ip.ip_p);
380 oip = &dp->icmp_ip;
381 hlen = IP_HL(oip) * 4;
382 ouh = (struct udphdr *)(((u_char *)oip) + hlen);
383 ND_TCHECK(ouh->uh_dport);
384 dport = EXTRACT_16BITS(&ouh->uh_dport);
385 switch (oip->ip_p) {
386
387 case IPPROTO_TCP:
388 (void)snprintf(buf, sizeof(buf),
389 "%s tcp port %s unreachable",
390 ipaddr_string(&oip->ip_dst),
391 tcpport_string(dport));
392 break;
393
394 case IPPROTO_UDP:
395 (void)snprintf(buf, sizeof(buf),
396 "%s udp port %s unreachable",
397 ipaddr_string(&oip->ip_dst),
398 udpport_string(dport));
399 break;
400
401 default:
402 (void)snprintf(buf, sizeof(buf),
403 "%s protocol %d port %d unreachable",
404 ipaddr_string(&oip->ip_dst),
405 oip->ip_p, dport);
406 break;
407 }
408 break;
409
410 case ICMP_UNREACH_NEEDFRAG:
411 {
412 register const struct mtu_discovery *mp;
413 mp = (struct mtu_discovery *)(u_char *)&dp->icmp_void;
414 mtu = EXTRACT_16BITS(&mp->nexthopmtu);
415 if (mtu) {
416 (void)snprintf(buf, sizeof(buf),
417 "%s unreachable - need to frag (mtu %d)",
418 ipaddr_string(&dp->icmp_ip.ip_dst), mtu);
419 } else {
420 (void)snprintf(buf, sizeof(buf),
421 "%s unreachable - need to frag",
422 ipaddr_string(&dp->icmp_ip.ip_dst));
423 }
424 }
425 break;
426
427 default:
428 fmt = tok2str(unreach2str, "#%d %%s unreachable",
429 dp->icmp_code);
430 (void)snprintf(buf, sizeof(buf), fmt,
431 ipaddr_string(&dp->icmp_ip.ip_dst));
432 break;
433 }
434 break;
435
436 case ICMP_REDIRECT:
437 ND_TCHECK(dp->icmp_ip.ip_dst);
438 fmt = tok2str(type2str, "redirect-#%d %%s to net %%s",
439 dp->icmp_code);
440 (void)snprintf(buf, sizeof(buf), fmt,
441 ipaddr_string(&dp->icmp_ip.ip_dst),
442 ipaddr_string(&dp->icmp_gwaddr));
443 break;
444
445 case ICMP_ROUTERADVERT:
446 {
447 register const struct ih_rdiscovery *ihp;
448 register const struct id_rdiscovery *idp;
449 u_int lifetime, num, size;
450
451 (void)snprintf(buf, sizeof(buf), "router advertisement");
452 cp = buf + strlen(buf);
453
454 ihp = (struct ih_rdiscovery *)&dp->icmp_void;
455 ND_TCHECK(*ihp);
456 (void)strncpy(cp, " lifetime ", sizeof(buf) - (cp - buf));
457 cp = buf + strlen(buf);
458 lifetime = EXTRACT_16BITS(&ihp->ird_lifetime);
459 if (lifetime < 60) {
460 (void)snprintf(cp, sizeof(buf) - (cp - buf), "%u",
461 lifetime);
462 } else if (lifetime < 60 * 60) {
463 (void)snprintf(cp, sizeof(buf) - (cp - buf), "%u:%02u",
464 lifetime / 60, lifetime % 60);
465 } else {
466 (void)snprintf(cp, sizeof(buf) - (cp - buf),
467 "%u:%02u:%02u",
468 lifetime / 3600,
469 (lifetime % 3600) / 60,
470 lifetime % 60);
471 }
472 cp = buf + strlen(buf);
473
474 num = ihp->ird_addrnum;
475 (void)snprintf(cp, sizeof(buf) - (cp - buf), " %d:", num);
476 cp = buf + strlen(buf);
477
478 size = ihp->ird_addrsiz;
479 if (size != 2) {
480 (void)snprintf(cp, sizeof(buf) - (cp - buf),
481 " [size %d]", size);
482 break;
483 }
484 idp = (struct id_rdiscovery *)&dp->icmp_data;
485 while (num-- > 0) {
486 ND_TCHECK(*idp);
487 (void)snprintf(cp, sizeof(buf) - (cp - buf), " {%s %u}",
488 ipaddr_string(&idp->ird_addr),
489 EXTRACT_32BITS(&idp->ird_pref));
490 cp = buf + strlen(buf);
491 ++idp;
492 }
493 }
494 break;
495
496 case ICMP_TIMXCEED:
497 ND_TCHECK(dp->icmp_ip.ip_dst);
498 switch (dp->icmp_code) {
499
500 case ICMP_TIMXCEED_INTRANS:
501 str = "time exceeded in-transit";
502 break;
503
504 case ICMP_TIMXCEED_REASS:
505 str = "ip reassembly time exceeded";
506 break;
507
508 default:
509 (void)snprintf(buf, sizeof(buf), "time exceeded-#%d",
510 dp->icmp_code);
511 break;
512 }
513 break;
514
515 case ICMP_PARAMPROB:
516 if (dp->icmp_code)
517 (void)snprintf(buf, sizeof(buf),
518 "parameter problem - code %d", dp->icmp_code);
519 else {
520 ND_TCHECK(dp->icmp_pptr);
521 (void)snprintf(buf, sizeof(buf),
522 "parameter problem - octet %d", dp->icmp_pptr);
523 }
524 break;
525
526 case ICMP_MASKREPLY:
527 ND_TCHECK(dp->icmp_mask);
528 (void)snprintf(buf, sizeof(buf), "address mask is 0x%08x",
529 EXTRACT_32BITS(&dp->icmp_mask));
530 break;
531
532 case ICMP_TSTAMP:
533 ND_TCHECK(dp->icmp_seq);
534 (void)snprintf(buf, sizeof(buf),
535 "time stamp query id %u seq %u",
536 EXTRACT_16BITS(&dp->icmp_id),
537 EXTRACT_16BITS(&dp->icmp_seq));
538 break;
539
540 case ICMP_TSTAMPREPLY:
541 ND_TCHECK(dp->icmp_ttime);
542 (void)snprintf(buf, sizeof(buf),
543 "time stamp reply id %u seq %u: org %s",
544 EXTRACT_16BITS(&dp->icmp_id),
545 EXTRACT_16BITS(&dp->icmp_seq),
546 icmp_tstamp_print(EXTRACT_32BITS(&dp->icmp_otime)));
547
548 (void)snprintf(buf+strlen(buf),sizeof(buf)-strlen(buf),", recv %s",
549 icmp_tstamp_print(EXTRACT_32BITS(&dp->icmp_rtime)));
550 (void)snprintf(buf+strlen(buf),sizeof(buf)-strlen(buf),", xmit %s",
551 icmp_tstamp_print(EXTRACT_32BITS(&dp->icmp_ttime)));
552 break;
553
554 default:
555 str = tok2str(icmp2str, "type-#%d", dp->icmp_type);
556 break;
557 }
558 ND_PRINT((ndo, "ICMP %s, length %u", str, plen));
559 if (ndo->ndo_vflag && !fragmented) { /* don't attempt checksumming if this is a frag */
560 u_int16_t sum, icmp_sum;
561 struct cksum_vec vec[1];
562 if (ND_TTEST2(*bp, plen)) {
563 vec[0].ptr = (const u_int8_t *)(void *)dp;
564 vec[0].len = plen;
565 sum = in_cksum(vec, 1);
566 if (sum != 0) {
567 icmp_sum = EXTRACT_16BITS(&dp->icmp_cksum);
568 ND_PRINT((ndo, " (wrong icmp cksum %x (->%x)!)",
569 icmp_sum,
570 in_cksum_shouldbe(icmp_sum, sum)));
571 }
572 }
573 }
574
575 /*
576 * print the remnants of the IP packet.
577 * save the snaplength as this may get overidden in the IP printer.
578 */
579 if (ndo->ndo_vflag >= 1 && !ICMP_INFOTYPE(dp->icmp_type)) {
580 bp += 8;
581 ND_PRINT((ndo, "\n\t"));
582 ip = (struct ip *)bp;
583 ndo->ndo_snaplen = ndo->ndo_snapend - bp;
584 snapend_save = ndo->ndo_snapend;
585 ip_print(ndo, bp, EXTRACT_16BITS(&ip->ip_len));
586 ndo->ndo_snapend = snapend_save;
587 }
588
589 /*
590 * Attempt to decode the MPLS extensions only for some ICMP types.
591 */
592 if (ndo->ndo_vflag >= 1 && plen > ICMP_EXTD_MINLEN && ICMP_MPLS_EXT_TYPE(dp->icmp_type)) {
593
594 ND_TCHECK(*ext_dp);
595
596 /*
597 * Check first if the mpls extension header shows a non-zero length.
598 * If the length field is not set then silently verify the checksum
599 * to check if an extension header is present. This is expedient,
600 * however not all implementations set the length field proper.
601 */
602 if (!ext_dp->icmp_length) {
603 vec[0].ptr = (const u_int8_t *)(void *)&ext_dp->icmp_ext_version_res;
604 vec[0].len = plen - ICMP_EXTD_MINLEN;
605 if (in_cksum(vec, 1)) {
606 return;
607 }
608 }
609
610 ND_PRINT((ndo, "\n\tMPLS extension v%u",
611 ICMP_MPLS_EXT_EXTRACT_VERSION(*(ext_dp->icmp_ext_version_res))));
612
613 /*
614 * Sanity checking of the header.
615 */
616 if (ICMP_MPLS_EXT_EXTRACT_VERSION(*(ext_dp->icmp_ext_version_res)) !=
617 ICMP_MPLS_EXT_VERSION) {
618 ND_PRINT((ndo, " packet not supported"));
619 return;
620 }
621
622 hlen = plen - ICMP_EXTD_MINLEN;
623 vec[0].ptr = (const u_int8_t *)(void *)&ext_dp->icmp_ext_version_res;
624 vec[0].len = hlen;
625 ND_PRINT((ndo, ", checksum 0x%04x (%scorrect), length %u",
626 EXTRACT_16BITS(ext_dp->icmp_ext_checksum),
627 in_cksum(vec, 1) ? "in" : "",
628 hlen));
629
630 hlen -= 4; /* subtract common header size */
631 obj_tptr = (u_int8_t *)ext_dp->icmp_ext_data;
632
633 while (hlen > sizeof(struct icmp_mpls_ext_object_header_t)) {
634
635 icmp_mpls_ext_object_header = (struct icmp_mpls_ext_object_header_t *)obj_tptr;
636 ND_TCHECK(*icmp_mpls_ext_object_header);
637 obj_tlen = EXTRACT_16BITS(icmp_mpls_ext_object_header->length);
638 obj_class_num = icmp_mpls_ext_object_header->class_num;
639 obj_ctype = icmp_mpls_ext_object_header->ctype;
640 obj_tptr += sizeof(struct icmp_mpls_ext_object_header_t);
641
642 ND_PRINT((ndo, "\n\t %s Object (%u), Class-Type: %u, length %u",
643 tok2str(icmp_mpls_ext_obj_values,"unknown",obj_class_num),
644 obj_class_num,
645 obj_ctype,
646 obj_tlen));
647
648 hlen-=sizeof(struct icmp_mpls_ext_object_header_t); /* length field includes tlv header */
649
650 /* infinite loop protection */
651 if ((obj_class_num == 0) ||
652 (obj_tlen < sizeof(struct icmp_mpls_ext_object_header_t))) {
653 return;
654 }
655 obj_tlen-=sizeof(struct icmp_mpls_ext_object_header_t);
656
657 switch (obj_class_num) {
658 case 1:
659 switch(obj_ctype) {
660 case 1:
661 ND_TCHECK2(*obj_tptr, 4);
662 raw_label = EXTRACT_32BITS(obj_tptr);
663 ND_PRINT((ndo, "\n\t label %u, exp %u", MPLS_LABEL(raw_label), MPLS_EXP(raw_label)));
664 if (MPLS_STACK(raw_label))
665 ND_PRINT((ndo, ", [S]"));
666 ND_PRINT((ndo, ", ttl %u", MPLS_TTL(raw_label)));
667 break;
668 default:
669 print_unknown_data(ndo, obj_tptr, "\n\t ", obj_tlen);
670 }
671 break;
672
673 /*
674 * FIXME those are the defined objects that lack a decoder
675 * you are welcome to contribute code ;-)
676 */
677 case 2:
678 default:
679 print_unknown_data(ndo, obj_tptr, "\n\t ", obj_tlen);
680 break;
681 }
682 if (hlen < obj_tlen)
683 break;
684 hlen -= obj_tlen;
685 obj_tptr += obj_tlen;
686 }
687 }
688
689 return;
690 trunc:
691 fputs("[|icmp]", stdout);
692 }
693 /*
694 * Local Variables:
695 * c-style: whitesmith
696 * c-basic-offset: 8
697 * End:
698 */
[mirror] the TCPdump network dissector