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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 uint8_t icmp_type; /* type of message, see below */
51 uint8_t icmp_code; /* type sub code */
52 uint16_t icmp_cksum; /* ones complement cksum of struct */
53 union {
54 uint8_t ih_pptr; /* ICMP_PARAMPROB */
55 struct in_addr ih_gwaddr; /* ICMP_REDIRECT */
56 struct ih_idseq {
57 uint16_t icd_id;
58 uint16_t icd_seq;
59 } ih_idseq;
60 uint32_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 uint32_t its_otime;
70 uint32_t its_rtime;
71 uint32_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 uint32_t id_mask;
78 uint8_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 (uint32_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_ERRTYPE(type) \
149 ((type) == ICMP_UNREACH || (type) == ICMP_SOURCEQUENCH || \
150 (type) == ICMP_REDIRECT || (type) == ICMP_TIMXCEED || \
151 (type) == ICMP_PARAMPROB)
152 #define ICMP_MPLS_EXT_TYPE(type) \
153 ((type) == ICMP_UNREACH || \
154 (type) == ICMP_TIMXCEED || \
155 (type) == ICMP_PARAMPROB)
156 /* rfc1700 */
157 #ifndef ICMP_UNREACH_NET_UNKNOWN
158 #define ICMP_UNREACH_NET_UNKNOWN 6 /* destination net unknown */
159 #endif
160 #ifndef ICMP_UNREACH_HOST_UNKNOWN
161 #define ICMP_UNREACH_HOST_UNKNOWN 7 /* destination host unknown */
162 #endif
163 #ifndef ICMP_UNREACH_ISOLATED
164 #define ICMP_UNREACH_ISOLATED 8 /* source host isolated */
165 #endif
166 #ifndef ICMP_UNREACH_NET_PROHIB
167 #define ICMP_UNREACH_NET_PROHIB 9 /* admin prohibited net */
168 #endif
169 #ifndef ICMP_UNREACH_HOST_PROHIB
170 #define ICMP_UNREACH_HOST_PROHIB 10 /* admin prohibited host */
171 #endif
172 #ifndef ICMP_UNREACH_TOSNET
173 #define ICMP_UNREACH_TOSNET 11 /* tos prohibited net */
174 #endif
175 #ifndef ICMP_UNREACH_TOSHOST
176 #define ICMP_UNREACH_TOSHOST 12 /* tos prohibited host */
177 #endif
178
179 /* rfc1716 */
180 #ifndef ICMP_UNREACH_FILTER_PROHIB
181 #define ICMP_UNREACH_FILTER_PROHIB 13 /* admin prohibited filter */
182 #endif
183 #ifndef ICMP_UNREACH_HOST_PRECEDENCE
184 #define ICMP_UNREACH_HOST_PRECEDENCE 14 /* host precedence violation */
185 #endif
186 #ifndef ICMP_UNREACH_PRECEDENCE_CUTOFF
187 #define ICMP_UNREACH_PRECEDENCE_CUTOFF 15 /* precedence cutoff */
188 #endif
189
190 /* Most of the icmp types */
191 static const struct tok icmp2str[] = {
192 { ICMP_ECHOREPLY, "echo reply" },
193 { ICMP_SOURCEQUENCH, "source quench" },
194 { ICMP_ECHO, "echo request" },
195 { ICMP_ROUTERSOLICIT, "router solicitation" },
196 { ICMP_TSTAMP, "time stamp request" },
197 { ICMP_TSTAMPREPLY, "time stamp reply" },
198 { ICMP_IREQ, "information request" },
199 { ICMP_IREQREPLY, "information reply" },
200 { ICMP_MASKREQ, "address mask request" },
201 { 0, NULL }
202 };
203
204 /* Formats for most of the ICMP_UNREACH codes */
205 static const struct tok unreach2str[] = {
206 { ICMP_UNREACH_NET, "net %s unreachable" },
207 { ICMP_UNREACH_HOST, "host %s unreachable" },
208 { ICMP_UNREACH_SRCFAIL,
209 "%s unreachable - source route failed" },
210 { ICMP_UNREACH_NET_UNKNOWN, "net %s unreachable - unknown" },
211 { ICMP_UNREACH_HOST_UNKNOWN, "host %s unreachable - unknown" },
212 { ICMP_UNREACH_ISOLATED,
213 "%s unreachable - source host isolated" },
214 { ICMP_UNREACH_NET_PROHIB,
215 "net %s unreachable - admin prohibited" },
216 { ICMP_UNREACH_HOST_PROHIB,
217 "host %s unreachable - admin prohibited" },
218 { ICMP_UNREACH_TOSNET,
219 "net %s unreachable - tos prohibited" },
220 { ICMP_UNREACH_TOSHOST,
221 "host %s unreachable - tos prohibited" },
222 { ICMP_UNREACH_FILTER_PROHIB,
223 "host %s unreachable - admin prohibited filter" },
224 { ICMP_UNREACH_HOST_PRECEDENCE,
225 "host %s unreachable - host precedence violation" },
226 { ICMP_UNREACH_PRECEDENCE_CUTOFF,
227 "host %s unreachable - precedence cutoff" },
228 { 0, NULL }
229 };
230
231 /* Formats for the ICMP_REDIRECT codes */
232 static const struct tok type2str[] = {
233 { ICMP_REDIRECT_NET, "redirect %s to net %s" },
234 { ICMP_REDIRECT_HOST, "redirect %s to host %s" },
235 { ICMP_REDIRECT_TOSNET, "redirect-tos %s to net %s" },
236 { ICMP_REDIRECT_TOSHOST, "redirect-tos %s to host %s" },
237 { 0, NULL }
238 };
239
240 /* rfc1191 */
241 struct mtu_discovery {
242 uint16_t unused;
243 uint16_t nexthopmtu;
244 };
245
246 /* rfc1256 */
247 struct ih_rdiscovery {
248 uint8_t ird_addrnum;
249 uint8_t ird_addrsiz;
250 uint16_t ird_lifetime;
251 };
252
253 struct id_rdiscovery {
254 uint32_t ird_addr;
255 uint32_t ird_pref;
256 };
257
258 /*
259 * draft-bonica-internet-icmp-08
260 *
261 * The Destination Unreachable, Time Exceeded
262 * and Parameter Problem messages are slighly changed as per
263 * the above draft. A new Length field gets added to give
264 * the caller an idea about the length of the piggypacked
265 * IP packet before the MPLS extension header starts.
266 *
267 * The Length field represents length of the padded "original datagram"
268 * field measured in 32-bit words.
269 *
270 * 0 1 2 3
271 * 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
272 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
273 * | Type | Code | Checksum |
274 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
275 * | unused | Length | unused |
276 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
277 * | Internet Header + leading octets of original datagram |
278 * | |
279 * | // |
280 * | |
281 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
282 */
283
284 struct icmp_ext_t {
285 uint8_t icmp_type;
286 uint8_t icmp_code;
287 uint8_t icmp_checksum[2];
288 uint8_t icmp_reserved;
289 uint8_t icmp_length;
290 uint8_t icmp_reserved2[2];
291 uint8_t icmp_ext_legacy_header[128]; /* extension header starts 128 bytes after ICMP header */
292 uint8_t icmp_ext_version_res[2];
293 uint8_t icmp_ext_checksum[2];
294 uint8_t icmp_ext_data[1];
295 };
296
297 struct icmp_mpls_ext_object_header_t {
298 uint8_t length[2];
299 uint8_t class_num;
300 uint8_t ctype;
301 };
302
303 static const struct tok icmp_mpls_ext_obj_values[] = {
304 { 1, "MPLS Stack Entry" },
305 { 2, "Extended Payload" },
306 { 0, NULL}
307 };
308
309 /* prototypes */
310 const char *icmp_tstamp_print(u_int);
311
312 /* print the milliseconds since midnight UTC */
313 const char *
314 icmp_tstamp_print(u_int tstamp) {
315 u_int msec,sec,min,hrs;
316
317 static char buf[64];
318
319 msec = tstamp % 1000;
320 sec = tstamp / 1000;
321 min = sec / 60; sec -= min * 60;
322 hrs = min / 60; min -= hrs * 60;
323 snprintf(buf, sizeof(buf), "%02u:%02u:%02u.%03u",hrs,min,sec,msec);
324 return buf;
325 }
326
327 void
328 icmp_print(netdissect_options *ndo, const u_char *bp, u_int plen, const u_char *bp2,
329 int fragmented)
330 {
331 char *cp;
332 const struct icmp *dp;
333 const struct icmp_ext_t *ext_dp;
334 const struct ip *ip;
335 const char *str, *fmt;
336 const struct ip *oip;
337 const struct udphdr *ouh;
338 const uint8_t *obj_tptr;
339 uint32_t raw_label;
340 const u_char *snapend_save;
341 const struct icmp_mpls_ext_object_header_t *icmp_mpls_ext_object_header;
342 u_int hlen, dport, mtu, obj_tlen, obj_class_num, obj_ctype;
343 char buf[MAXHOSTNAMELEN + 100];
344 struct cksum_vec vec[1];
345
346 dp = (struct icmp *)bp;
347 ext_dp = (struct icmp_ext_t *)bp;
348 ip = (struct ip *)bp2;
349 str = buf;
350
351 ND_TCHECK(dp->icmp_code);
352 switch (dp->icmp_type) {
353
354 case ICMP_ECHO:
355 case ICMP_ECHOREPLY:
356 ND_TCHECK(dp->icmp_seq);
357 (void)snprintf(buf, sizeof(buf), "echo %s, id %u, seq %u",
358 dp->icmp_type == ICMP_ECHO ?
359 "request" : "reply",
360 EXTRACT_16BITS(&dp->icmp_id),
361 EXTRACT_16BITS(&dp->icmp_seq));
362 break;
363
364 case ICMP_UNREACH:
365 ND_TCHECK(dp->icmp_ip.ip_dst);
366 switch (dp->icmp_code) {
367
368 case ICMP_UNREACH_PROTOCOL:
369 ND_TCHECK(dp->icmp_ip.ip_p);
370 (void)snprintf(buf, sizeof(buf),
371 "%s protocol %d unreachable",
372 ipaddr_string(ndo, &dp->icmp_ip.ip_dst),
373 dp->icmp_ip.ip_p);
374 break;
375
376 case ICMP_UNREACH_PORT:
377 ND_TCHECK(dp->icmp_ip.ip_p);
378 oip = &dp->icmp_ip;
379 hlen = IP_HL(oip) * 4;
380 ouh = (struct udphdr *)(((u_char *)oip) + hlen);
381 ND_TCHECK(ouh->uh_dport);
382 dport = EXTRACT_16BITS(&ouh->uh_dport);
383 switch (oip->ip_p) {
384
385 case IPPROTO_TCP:
386 (void)snprintf(buf, sizeof(buf),
387 "%s tcp port %s unreachable",
388 ipaddr_string(ndo, &oip->ip_dst),
389 tcpport_string(dport));
390 break;
391
392 case IPPROTO_UDP:
393 (void)snprintf(buf, sizeof(buf),
394 "%s udp port %s unreachable",
395 ipaddr_string(ndo, &oip->ip_dst),
396 udpport_string(dport));
397 break;
398
399 default:
400 (void)snprintf(buf, sizeof(buf),
401 "%s protocol %d port %d unreachable",
402 ipaddr_string(ndo, &oip->ip_dst),
403 oip->ip_p, dport);
404 break;
405 }
406 break;
407
408 case ICMP_UNREACH_NEEDFRAG:
409 {
410 register const struct mtu_discovery *mp;
411 mp = (struct mtu_discovery *)(u_char *)&dp->icmp_void;
412 mtu = EXTRACT_16BITS(&mp->nexthopmtu);
413 if (mtu) {
414 (void)snprintf(buf, sizeof(buf),
415 "%s unreachable - need to frag (mtu %d)",
416 ipaddr_string(ndo, &dp->icmp_ip.ip_dst), mtu);
417 } else {
418 (void)snprintf(buf, sizeof(buf),
419 "%s unreachable - need to frag",
420 ipaddr_string(ndo, &dp->icmp_ip.ip_dst));
421 }
422 }
423 break;
424
425 default:
426 fmt = tok2str(unreach2str, "#%d %%s unreachable",
427 dp->icmp_code);
428 (void)snprintf(buf, sizeof(buf), fmt,
429 ipaddr_string(ndo, &dp->icmp_ip.ip_dst));
430 break;
431 }
432 break;
433
434 case ICMP_REDIRECT:
435 ND_TCHECK(dp->icmp_ip.ip_dst);
436 fmt = tok2str(type2str, "redirect-#%d %%s to net %%s",
437 dp->icmp_code);
438 (void)snprintf(buf, sizeof(buf), fmt,
439 ipaddr_string(ndo, &dp->icmp_ip.ip_dst),
440 ipaddr_string(ndo, &dp->icmp_gwaddr));
441 break;
442
443 case ICMP_ROUTERADVERT:
444 {
445 register const struct ih_rdiscovery *ihp;
446 register const struct id_rdiscovery *idp;
447 u_int lifetime, num, size;
448
449 (void)snprintf(buf, sizeof(buf), "router advertisement");
450 cp = buf + strlen(buf);
451
452 ihp = (struct ih_rdiscovery *)&dp->icmp_void;
453 ND_TCHECK(*ihp);
454 (void)strncpy(cp, " lifetime ", sizeof(buf) - (cp - buf));
455 cp = buf + strlen(buf);
456 lifetime = EXTRACT_16BITS(&ihp->ird_lifetime);
457 if (lifetime < 60) {
458 (void)snprintf(cp, sizeof(buf) - (cp - buf), "%u",
459 lifetime);
460 } else if (lifetime < 60 * 60) {
461 (void)snprintf(cp, sizeof(buf) - (cp - buf), "%u:%02u",
462 lifetime / 60, lifetime % 60);
463 } else {
464 (void)snprintf(cp, sizeof(buf) - (cp - buf),
465 "%u:%02u:%02u",
466 lifetime / 3600,
467 (lifetime % 3600) / 60,
468 lifetime % 60);
469 }
470 cp = buf + strlen(buf);
471
472 num = ihp->ird_addrnum;
473 (void)snprintf(cp, sizeof(buf) - (cp - buf), " %d:", num);
474 cp = buf + strlen(buf);
475
476 size = ihp->ird_addrsiz;
477 if (size != 2) {
478 (void)snprintf(cp, sizeof(buf) - (cp - buf),
479 " [size %d]", size);
480 break;
481 }
482 idp = (struct id_rdiscovery *)&dp->icmp_data;
483 while (num-- > 0) {
484 ND_TCHECK(*idp);
485 (void)snprintf(cp, sizeof(buf) - (cp - buf), " {%s %u}",
486 ipaddr_string(ndo, &idp->ird_addr),
487 EXTRACT_32BITS(&idp->ird_pref));
488 cp = buf + strlen(buf);
489 ++idp;
490 }
491 }
492 break;
493
494 case ICMP_TIMXCEED:
495 ND_TCHECK(dp->icmp_ip.ip_dst);
496 switch (dp->icmp_code) {
497
498 case ICMP_TIMXCEED_INTRANS:
499 str = "time exceeded in-transit";
500 break;
501
502 case ICMP_TIMXCEED_REASS:
503 str = "ip reassembly time exceeded";
504 break;
505
506 default:
507 (void)snprintf(buf, sizeof(buf), "time exceeded-#%d",
508 dp->icmp_code);
509 break;
510 }
511 break;
512
513 case ICMP_PARAMPROB:
514 if (dp->icmp_code)
515 (void)snprintf(buf, sizeof(buf),
516 "parameter problem - code %d", dp->icmp_code);
517 else {
518 ND_TCHECK(dp->icmp_pptr);
519 (void)snprintf(buf, sizeof(buf),
520 "parameter problem - octet %d", dp->icmp_pptr);
521 }
522 break;
523
524 case ICMP_MASKREPLY:
525 ND_TCHECK(dp->icmp_mask);
526 (void)snprintf(buf, sizeof(buf), "address mask is 0x%08x",
527 EXTRACT_32BITS(&dp->icmp_mask));
528 break;
529
530 case ICMP_TSTAMP:
531 ND_TCHECK(dp->icmp_seq);
532 (void)snprintf(buf, sizeof(buf),
533 "time stamp query id %u seq %u",
534 EXTRACT_16BITS(&dp->icmp_id),
535 EXTRACT_16BITS(&dp->icmp_seq));
536 break;
537
538 case ICMP_TSTAMPREPLY:
539 ND_TCHECK(dp->icmp_ttime);
540 (void)snprintf(buf, sizeof(buf),
541 "time stamp reply id %u seq %u: org %s",
542 EXTRACT_16BITS(&dp->icmp_id),
543 EXTRACT_16BITS(&dp->icmp_seq),
544 icmp_tstamp_print(EXTRACT_32BITS(&dp->icmp_otime)));
545
546 (void)snprintf(buf+strlen(buf),sizeof(buf)-strlen(buf),", recv %s",
547 icmp_tstamp_print(EXTRACT_32BITS(&dp->icmp_rtime)));
548 (void)snprintf(buf+strlen(buf),sizeof(buf)-strlen(buf),", xmit %s",
549 icmp_tstamp_print(EXTRACT_32BITS(&dp->icmp_ttime)));
550 break;
551
552 default:
553 str = tok2str(icmp2str, "type-#%d", dp->icmp_type);
554 break;
555 }
556 ND_PRINT((ndo, "ICMP %s, length %u", str, plen));
557 if (ndo->ndo_vflag && !fragmented) { /* don't attempt checksumming if this is a frag */
558 uint16_t sum, icmp_sum;
559 struct cksum_vec vec[1];
560 if (ND_TTEST2(*bp, plen)) {
561 vec[0].ptr = (const uint8_t *)(void *)dp;
562 vec[0].len = plen;
563 sum = in_cksum(vec, 1);
564 if (sum != 0) {
565 icmp_sum = EXTRACT_16BITS(&dp->icmp_cksum);
566 ND_PRINT((ndo, " (wrong icmp cksum %x (->%x)!)",
567 icmp_sum,
568 in_cksum_shouldbe(icmp_sum, sum)));
569 }
570 }
571 }
572
573 /*
574 * print the remnants of the IP packet.
575 * save the snaplength as this may get overidden in the IP printer.
576 */
577 if (ndo->ndo_vflag >= 1 && ICMP_ERRTYPE(dp->icmp_type)) {
578 bp += 8;
579 ND_PRINT((ndo, "\n\t"));
580 ip = (struct ip *)bp;
581 ndo->ndo_snaplen = ndo->ndo_snapend - bp;
582 snapend_save = ndo->ndo_snapend;
583 ip_print(ndo, bp, EXTRACT_16BITS(&ip->ip_len));
584 ndo->ndo_snapend = snapend_save;
585 }
586
587 /*
588 * Attempt to decode the MPLS extensions only for some ICMP types.
589 */
590 if (ndo->ndo_vflag >= 1 && plen > ICMP_EXTD_MINLEN && ICMP_MPLS_EXT_TYPE(dp->icmp_type)) {
591
592 ND_TCHECK(*ext_dp);
593
594 /*
595 * Check first if the mpls extension header shows a non-zero length.
596 * If the length field is not set then silently verify the checksum
597 * to check if an extension header is present. This is expedient,
598 * however not all implementations set the length field proper.
599 */
600 if (!ext_dp->icmp_length) {
601 vec[0].ptr = (const uint8_t *)(void *)&ext_dp->icmp_ext_version_res;
602 vec[0].len = plen - ICMP_EXTD_MINLEN;
603 if (in_cksum(vec, 1)) {
604 return;
605 }
606 }
607
608 ND_PRINT((ndo, "\n\tMPLS extension v%u",
609 ICMP_MPLS_EXT_EXTRACT_VERSION(*(ext_dp->icmp_ext_version_res))));
610
611 /*
612 * Sanity checking of the header.
613 */
614 if (ICMP_MPLS_EXT_EXTRACT_VERSION(*(ext_dp->icmp_ext_version_res)) !=
615 ICMP_MPLS_EXT_VERSION) {
616 ND_PRINT((ndo, " packet not supported"));
617 return;
618 }
619
620 hlen = plen - ICMP_EXTD_MINLEN;
621 vec[0].ptr = (const uint8_t *)(void *)&ext_dp->icmp_ext_version_res;
622 vec[0].len = hlen;
623 ND_PRINT((ndo, ", checksum 0x%04x (%scorrect), length %u",
624 EXTRACT_16BITS(ext_dp->icmp_ext_checksum),
625 in_cksum(vec, 1) ? "in" : "",
626 hlen));
627
628 hlen -= 4; /* subtract common header size */
629 obj_tptr = (uint8_t *)ext_dp->icmp_ext_data;
630
631 while (hlen > sizeof(struct icmp_mpls_ext_object_header_t)) {
632
633 icmp_mpls_ext_object_header = (struct icmp_mpls_ext_object_header_t *)obj_tptr;
634 ND_TCHECK(*icmp_mpls_ext_object_header);
635 obj_tlen = EXTRACT_16BITS(icmp_mpls_ext_object_header->length);
636 obj_class_num = icmp_mpls_ext_object_header->class_num;
637 obj_ctype = icmp_mpls_ext_object_header->ctype;
638 obj_tptr += sizeof(struct icmp_mpls_ext_object_header_t);
639
640 ND_PRINT((ndo, "\n\t %s Object (%u), Class-Type: %u, length %u",
641 tok2str(icmp_mpls_ext_obj_values,"unknown",obj_class_num),
642 obj_class_num,
643 obj_ctype,
644 obj_tlen));
645
646 hlen-=sizeof(struct icmp_mpls_ext_object_header_t); /* length field includes tlv header */
647
648 /* infinite loop protection */
649 if ((obj_class_num == 0) ||
650 (obj_tlen < sizeof(struct icmp_mpls_ext_object_header_t))) {
651 return;
652 }
653 obj_tlen-=sizeof(struct icmp_mpls_ext_object_header_t);
654
655 switch (obj_class_num) {
656 case 1:
657 switch(obj_ctype) {
658 case 1:
659 ND_TCHECK2(*obj_tptr, 4);
660 raw_label = EXTRACT_32BITS(obj_tptr);
661 ND_PRINT((ndo, "\n\t label %u, exp %u", MPLS_LABEL(raw_label), MPLS_EXP(raw_label)));
662 if (MPLS_STACK(raw_label))
663 ND_PRINT((ndo, ", [S]"));
664 ND_PRINT((ndo, ", ttl %u", MPLS_TTL(raw_label)));
665 break;
666 default:
667 print_unknown_data(ndo, obj_tptr, "\n\t ", obj_tlen);
668 }
669 break;
670
671 /*
672 * FIXME those are the defined objects that lack a decoder
673 * you are welcome to contribute code ;-)
674 */
675 case 2:
676 default:
677 print_unknown_data(ndo, obj_tptr, "\n\t ", obj_tlen);
678 break;
679 }
680 if (hlen < obj_tlen)
681 break;
682 hlen -= obj_tlen;
683 obj_tptr += obj_tlen;
684 }
685 }
686
687 return;
688 trunc:
689 ND_PRINT((ndo, "[|icmp]"));
690 }
691 /*
692 * Local Variables:
693 * c-style: whitesmith
694 * c-basic-offset: 8
695 * End:
696 */
[mirror] the TCPdump network dissector