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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 /* \summary: Internet Control Message Protocol (ICMP) printer */
23
24 #ifdef HAVE_CONFIG_H
25 #include <config.h>
26 #endif
27
28 #include "netdissect-stdinc.h"
29
30 #include <stdio.h>
31 #include <string.h>
32
33 #include "netdissect.h"
34 #include "addrtoname.h"
35 #include "extract.h"
36
37 #include "ip.h"
38 #include "udp.h"
39 #include "ipproto.h"
40 #include "mpls.h"
41
42 /*
43 * Interface Control Message Protocol Definitions.
44 * Per RFC 792, September 1981.
45 */
46
47 /*
48 * Structure of an icmp header.
49 */
50 struct icmp {
51 nd_uint8_t icmp_type; /* type of message, see below */
52 nd_uint8_t icmp_code; /* type sub code */
53 nd_uint16_t icmp_cksum; /* ones complement cksum of struct */
54 union {
55 nd_uint8_t ih_pptr; /* ICMP_PARAMPROB */
56 nd_ipv4 ih_gwaddr; /* ICMP_REDIRECT */
57 struct ih_idseq {
58 nd_uint16_t icd_id;
59 nd_uint16_t icd_seq;
60 } ih_idseq;
61 nd_uint32_t ih_void;
62 } icmp_hun;
63 #define icmp_pptr icmp_hun.ih_pptr
64 #define icmp_gwaddr icmp_hun.ih_gwaddr
65 #define icmp_id icmp_hun.ih_idseq.icd_id
66 #define icmp_seq icmp_hun.ih_idseq.icd_seq
67 #define icmp_void icmp_hun.ih_void
68 union {
69 struct id_ts {
70 nd_uint32_t its_otime;
71 nd_uint32_t its_rtime;
72 nd_uint32_t its_ttime;
73 } id_ts;
74 struct id_ip {
75 struct ip idi_ip;
76 /* options and then 64 bits of data */
77 } id_ip;
78 nd_uint32_t id_mask;
79 nd_byte id_data[1];
80 } icmp_dun;
81 #define icmp_otime icmp_dun.id_ts.its_otime
82 #define icmp_rtime icmp_dun.id_ts.its_rtime
83 #define icmp_ttime icmp_dun.id_ts.its_ttime
84 #define icmp_ip icmp_dun.id_ip.idi_ip
85 #define icmp_mask icmp_dun.id_mask
86 #define icmp_data icmp_dun.id_data
87 };
88
89 #define ICMP_MPLS_EXT_EXTRACT_VERSION(x) (((x)&0xf0)>>4)
90 #define ICMP_MPLS_EXT_VERSION 2
91
92 /*
93 * Lower bounds on packet lengths for various types.
94 * For the error advice packets must first insure that the
95 * packet is large enought to contain the returned ip header.
96 * Only then can we do the check to see if 64 bits of packet
97 * data have been returned, since we need to check the returned
98 * ip header length.
99 */
100 #define ICMP_MINLEN 8 /* abs minimum */
101 #define ICMP_EXTD_MINLEN (156 - sizeof (struct ip)) /* draft-bonica-internet-icmp-08 */
102 #define ICMP_TSLEN (8 + 3 * sizeof (uint32_t)) /* timestamp */
103 #define ICMP_MASKLEN 12 /* address mask */
104 #define ICMP_ADVLENMIN (8 + sizeof (struct ip) + 8) /* min */
105 #define ICMP_ADVLEN(p) (8 + (IP_HL(&(p)->icmp_ip) << 2) + 8)
106 /* N.B.: must separately check that ip_hl >= 5 */
107
108 /*
109 * Definition of type and code field values.
110 */
111 #define ICMP_ECHOREPLY 0 /* echo reply */
112 #define ICMP_UNREACH 3 /* dest unreachable, codes: */
113 #define ICMP_UNREACH_NET 0 /* bad net */
114 #define ICMP_UNREACH_HOST 1 /* bad host */
115 #define ICMP_UNREACH_PROTOCOL 2 /* bad protocol */
116 #define ICMP_UNREACH_PORT 3 /* bad port */
117 #define ICMP_UNREACH_NEEDFRAG 4 /* IP_DF caused drop */
118 #define ICMP_UNREACH_SRCFAIL 5 /* src route failed */
119 #define ICMP_UNREACH_NET_UNKNOWN 6 /* unknown net */
120 #define ICMP_UNREACH_HOST_UNKNOWN 7 /* unknown host */
121 #define ICMP_UNREACH_ISOLATED 8 /* src host isolated */
122 #define ICMP_UNREACH_NET_PROHIB 9 /* prohibited access */
123 #define ICMP_UNREACH_HOST_PROHIB 10 /* ditto */
124 #define ICMP_UNREACH_TOSNET 11 /* bad tos for net */
125 #define ICMP_UNREACH_TOSHOST 12 /* bad tos for host */
126 #define ICMP_SOURCEQUENCH 4 /* packet lost, slow down */
127 #define ICMP_REDIRECT 5 /* shorter route, codes: */
128 #define ICMP_REDIRECT_NET 0 /* for network */
129 #define ICMP_REDIRECT_HOST 1 /* for host */
130 #define ICMP_REDIRECT_TOSNET 2 /* for tos and net */
131 #define ICMP_REDIRECT_TOSHOST 3 /* for tos and host */
132 #define ICMP_ECHO 8 /* echo service */
133 #define ICMP_ROUTERADVERT 9 /* router advertisement */
134 #define ICMP_ROUTERSOLICIT 10 /* router solicitation */
135 #define ICMP_TIMXCEED 11 /* time exceeded, code: */
136 #define ICMP_TIMXCEED_INTRANS 0 /* ttl==0 in transit */
137 #define ICMP_TIMXCEED_REASS 1 /* ttl==0 in reass */
138 #define ICMP_PARAMPROB 12 /* ip header bad */
139 #define ICMP_PARAMPROB_OPTABSENT 1 /* req. opt. absent */
140 #define ICMP_TSTAMP 13 /* timestamp request */
141 #define ICMP_TSTAMPREPLY 14 /* timestamp reply */
142 #define ICMP_IREQ 15 /* information request */
143 #define ICMP_IREQREPLY 16 /* information reply */
144 #define ICMP_MASKREQ 17 /* address mask request */
145 #define ICMP_MASKREPLY 18 /* address mask reply */
146
147 #define ICMP_MAXTYPE 18
148
149 #define ICMP_ERRTYPE(type) \
150 ((type) == ICMP_UNREACH || (type) == ICMP_SOURCEQUENCH || \
151 (type) == ICMP_REDIRECT || (type) == ICMP_TIMXCEED || \
152 (type) == ICMP_PARAMPROB)
153 #define ICMP_MPLS_EXT_TYPE(type) \
154 ((type) == ICMP_UNREACH || \
155 (type) == ICMP_TIMXCEED || \
156 (type) == ICMP_PARAMPROB)
157 /* rfc1700 */
158 #ifndef ICMP_UNREACH_NET_UNKNOWN
159 #define ICMP_UNREACH_NET_UNKNOWN 6 /* destination net unknown */
160 #endif
161 #ifndef ICMP_UNREACH_HOST_UNKNOWN
162 #define ICMP_UNREACH_HOST_UNKNOWN 7 /* destination host unknown */
163 #endif
164 #ifndef ICMP_UNREACH_ISOLATED
165 #define ICMP_UNREACH_ISOLATED 8 /* source host isolated */
166 #endif
167 #ifndef ICMP_UNREACH_NET_PROHIB
168 #define ICMP_UNREACH_NET_PROHIB 9 /* admin prohibited net */
169 #endif
170 #ifndef ICMP_UNREACH_HOST_PROHIB
171 #define ICMP_UNREACH_HOST_PROHIB 10 /* admin prohibited host */
172 #endif
173 #ifndef ICMP_UNREACH_TOSNET
174 #define ICMP_UNREACH_TOSNET 11 /* tos prohibited net */
175 #endif
176 #ifndef ICMP_UNREACH_TOSHOST
177 #define ICMP_UNREACH_TOSHOST 12 /* tos prohibited host */
178 #endif
179
180 /* rfc1716 */
181 #ifndef ICMP_UNREACH_FILTER_PROHIB
182 #define ICMP_UNREACH_FILTER_PROHIB 13 /* admin prohibited filter */
183 #endif
184 #ifndef ICMP_UNREACH_HOST_PRECEDENCE
185 #define ICMP_UNREACH_HOST_PRECEDENCE 14 /* host precedence violation */
186 #endif
187 #ifndef ICMP_UNREACH_PRECEDENCE_CUTOFF
188 #define ICMP_UNREACH_PRECEDENCE_CUTOFF 15 /* precedence cutoff */
189 #endif
190
191 /* Most of the icmp types */
192 static const struct tok icmp2str[] = {
193 { ICMP_ECHOREPLY, "echo reply" },
194 { ICMP_SOURCEQUENCH, "source quench" },
195 { ICMP_ECHO, "echo request" },
196 { ICMP_ROUTERSOLICIT, "router solicitation" },
197 { ICMP_TSTAMP, "time stamp request" },
198 { ICMP_TSTAMPREPLY, "time stamp reply" },
199 { ICMP_IREQ, "information request" },
200 { ICMP_IREQREPLY, "information reply" },
201 { ICMP_MASKREQ, "address mask request" },
202 { 0, NULL }
203 };
204
205 /* rfc1191 */
206 struct mtu_discovery {
207 nd_uint16_t unused;
208 nd_uint16_t nexthopmtu;
209 };
210
211 /* rfc1256 */
212 struct ih_rdiscovery {
213 nd_uint8_t ird_addrnum;
214 nd_uint8_t ird_addrsiz;
215 nd_uint16_t ird_lifetime;
216 };
217
218 struct id_rdiscovery {
219 nd_uint32_t ird_addr;
220 nd_uint32_t ird_pref;
221 };
222
223 /*
224 * draft-bonica-internet-icmp-08
225 *
226 * The Destination Unreachable, Time Exceeded
227 * and Parameter Problem messages are slightly changed as per
228 * the above draft. A new Length field gets added to give
229 * the caller an idea about the length of the piggypacked
230 * IP packet before the MPLS extension header starts.
231 *
232 * The Length field represents length of the padded "original datagram"
233 * field measured in 32-bit words.
234 *
235 * 0 1 2 3
236 * 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
237 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
238 * | Type | Code | Checksum |
239 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
240 * | unused | Length | unused |
241 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
242 * | Internet Header + leading octets of original datagram |
243 * | |
244 * | // |
245 * | |
246 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
247 */
248
249 struct icmp_ext_t {
250 nd_uint8_t icmp_type;
251 nd_uint8_t icmp_code;
252 nd_uint16_t icmp_checksum;
253 nd_byte icmp_reserved;
254 nd_uint8_t icmp_length;
255 nd_byte icmp_reserved2[2];
256 nd_byte icmp_ext_legacy_header[128]; /* extension header starts 128 bytes after ICMP header */
257 nd_byte icmp_ext_version_res[2];
258 nd_uint16_t icmp_ext_checksum;
259 nd_byte icmp_ext_data[1];
260 };
261
262 struct icmp_mpls_ext_object_header_t {
263 nd_uint16_t length;
264 nd_uint8_t class_num;
265 nd_uint8_t ctype;
266 };
267
268 static const struct tok icmp_mpls_ext_obj_values[] = {
269 { 1, "MPLS Stack Entry" },
270 { 2, "Extended Payload" },
271 { 0, NULL}
272 };
273
274 /* prototypes */
275 const char *icmp_tstamp_print(u_int);
276
277 /* print the milliseconds since midnight UTC */
278 const char *
279 icmp_tstamp_print(u_int tstamp)
280 {
281 u_int msec,sec,min,hrs;
282
283 static char buf[64];
284
285 msec = tstamp % 1000;
286 sec = tstamp / 1000;
287 min = sec / 60; sec -= min * 60;
288 hrs = min / 60; min -= hrs * 60;
289 snprintf(buf, sizeof(buf), "%02u:%02u:%02u.%03u",hrs,min,sec,msec);
290 return buf;
291 }
292
293 void
294 icmp_print(netdissect_options *ndo, const u_char *bp, u_int plen, const u_char *bp2,
295 int fragmented)
296 {
297 char *cp;
298 const struct icmp *dp;
299 uint8_t icmp_type, icmp_code;
300 const struct icmp_ext_t *ext_dp;
301 const struct ip *ip;
302 const char *str;
303 const struct ip *oip;
304 uint8_t ip_proto;
305 const struct udphdr *ouh;
306 const uint8_t *obj_tptr;
307 uint32_t raw_label;
308 const u_char *snapend_save;
309 const struct icmp_mpls_ext_object_header_t *icmp_mpls_ext_object_header;
310 u_int hlen, mtu, obj_tlen, obj_class_num, obj_ctype;
311 uint16_t dport;
312 char buf[MAXHOSTNAMELEN + 100];
313 struct cksum_vec vec[1];
314
315 ndo->ndo_protocol = "icmp";
316 dp = (const struct icmp *)bp;
317 ext_dp = (const struct icmp_ext_t *)bp;
318 ip = (const struct ip *)bp2;
319 str = buf;
320
321 icmp_type = GET_U_1(dp->icmp_type);
322 icmp_code = GET_U_1(dp->icmp_code);
323 switch (icmp_type) {
324
325 case ICMP_ECHO:
326 case ICMP_ECHOREPLY:
327 (void)snprintf(buf, sizeof(buf), "echo %s, id %u, seq %u",
328 icmp_type == ICMP_ECHO ?
329 "request" : "reply",
330 GET_BE_U_2(dp->icmp_id),
331 GET_BE_U_2(dp->icmp_seq));
332 break;
333
334 case ICMP_UNREACH:
335 switch (icmp_code) {
336
337 case ICMP_UNREACH_NET:
338 (void)snprintf(buf, sizeof(buf),
339 "net %s unreachable",
340 GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
341 break;
342
343 case ICMP_UNREACH_HOST:
344 (void)snprintf(buf, sizeof(buf),
345 "host %s unreachable",
346 GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
347 break;
348
349 case ICMP_UNREACH_PROTOCOL:
350 (void)snprintf(buf, sizeof(buf),
351 "%s protocol %u unreachable",
352 GET_IPADDR_STRING(dp->icmp_ip.ip_dst),
353 GET_U_1(dp->icmp_ip.ip_p));
354 break;
355
356 case ICMP_UNREACH_PORT:
357 ND_TCHECK_1(dp->icmp_ip.ip_p);
358 oip = &dp->icmp_ip;
359 hlen = IP_HL(oip) * 4;
360 ouh = (const struct udphdr *)(((const u_char *)oip) + hlen);
361 dport = GET_BE_U_2(ouh->uh_dport);
362 ip_proto = GET_U_1(oip->ip_p);
363 switch (ip_proto) {
364
365 case IPPROTO_TCP:
366 (void)snprintf(buf, sizeof(buf),
367 "%s tcp port %s unreachable",
368 GET_IPADDR_STRING(oip->ip_dst),
369 tcpport_string(ndo, dport));
370 break;
371
372 case IPPROTO_UDP:
373 (void)snprintf(buf, sizeof(buf),
374 "%s udp port %s unreachable",
375 GET_IPADDR_STRING(oip->ip_dst),
376 udpport_string(ndo, dport));
377 break;
378
379 default:
380 (void)snprintf(buf, sizeof(buf),
381 "%s protocol %u port %u unreachable",
382 GET_IPADDR_STRING(oip->ip_dst),
383 ip_proto, dport);
384 break;
385 }
386 break;
387
388 case ICMP_UNREACH_NEEDFRAG:
389 {
390 const struct mtu_discovery *mp;
391 mp = (const struct mtu_discovery *)(const u_char *)&dp->icmp_void;
392 mtu = GET_BE_U_2(mp->nexthopmtu);
393 if (mtu) {
394 (void)snprintf(buf, sizeof(buf),
395 "%s unreachable - need to frag (mtu %u)",
396 GET_IPADDR_STRING(dp->icmp_ip.ip_dst), mtu);
397 } else {
398 (void)snprintf(buf, sizeof(buf),
399 "%s unreachable - need to frag",
400 GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
401 }
402 }
403 break;
404
405 case ICMP_UNREACH_SRCFAIL:
406 (void)snprintf(buf, sizeof(buf),
407 "%s unreachable - source route failed",
408 GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
409 break;
410
411 case ICMP_UNREACH_NET_UNKNOWN:
412 (void)snprintf(buf, sizeof(buf),
413 "net %s unreachable - unknown",
414 GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
415 break;
416
417 case ICMP_UNREACH_HOST_UNKNOWN:
418 (void)snprintf(buf, sizeof(buf),
419 "host %s unreachable - unknown",
420 GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
421 break;
422
423 case ICMP_UNREACH_ISOLATED:
424 (void)snprintf(buf, sizeof(buf),
425 "%s unreachable - source host isolated",
426 GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
427 break;
428
429 case ICMP_UNREACH_NET_PROHIB:
430 (void)snprintf(buf, sizeof(buf),
431 "net %s unreachable - admin prohibited",
432 GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
433 break;
434
435 case ICMP_UNREACH_HOST_PROHIB:
436 (void)snprintf(buf, sizeof(buf),
437 "host %s unreachable - admin prohibited",
438 GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
439 break;
440
441 case ICMP_UNREACH_TOSNET:
442 (void)snprintf(buf, sizeof(buf),
443 "net %s unreachable - tos prohibited",
444 GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
445 break;
446
447 case ICMP_UNREACH_TOSHOST:
448 (void)snprintf(buf, sizeof(buf),
449 "host %s unreachable - tos prohibited",
450 GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
451 break;
452
453 case ICMP_UNREACH_FILTER_PROHIB:
454 (void)snprintf(buf, sizeof(buf),
455 "host %s unreachable - admin prohibited filter",
456 GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
457 break;
458
459 case ICMP_UNREACH_HOST_PRECEDENCE:
460 (void)snprintf(buf, sizeof(buf),
461 "host %s unreachable - host precedence violation",
462 GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
463 break;
464
465 case ICMP_UNREACH_PRECEDENCE_CUTOFF:
466 (void)snprintf(buf, sizeof(buf),
467 "host %s unreachable - precedence cutoff",
468 GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
469 break;
470
471 default:
472 (void)snprintf(buf, sizeof(buf),
473 "%s unreachable - #%u",
474 GET_IPADDR_STRING(dp->icmp_ip.ip_dst),
475 icmp_code);
476 break;
477 }
478 break;
479
480 case ICMP_REDIRECT:
481 switch (icmp_code) {
482
483 case ICMP_REDIRECT_NET:
484 (void)snprintf(buf, sizeof(buf),
485 "redirect %s to net %s",
486 GET_IPADDR_STRING(dp->icmp_ip.ip_dst),
487 GET_IPADDR_STRING(dp->icmp_gwaddr));
488 break;
489
490 case ICMP_REDIRECT_HOST:
491 (void)snprintf(buf, sizeof(buf),
492 "redirect %s to host %s",
493 GET_IPADDR_STRING(dp->icmp_ip.ip_dst),
494 GET_IPADDR_STRING(dp->icmp_gwaddr));
495 break;
496
497 case ICMP_REDIRECT_TOSNET:
498 (void)snprintf(buf, sizeof(buf),
499 "redirect-tos %s to net %s",
500 GET_IPADDR_STRING(dp->icmp_ip.ip_dst),
501 GET_IPADDR_STRING(dp->icmp_gwaddr));
502 break;
503
504 case ICMP_REDIRECT_TOSHOST:
505 (void)snprintf(buf, sizeof(buf),
506 "redirect-tos %s to host %s",
507 GET_IPADDR_STRING(dp->icmp_ip.ip_dst),
508 GET_IPADDR_STRING(dp->icmp_gwaddr));
509 break;
510
511 default:
512 (void)snprintf(buf, sizeof(buf),
513 "redirect-#%u %s to %s", icmp_code,
514 GET_IPADDR_STRING(dp->icmp_ip.ip_dst),
515 GET_IPADDR_STRING(dp->icmp_gwaddr));
516 break;
517 }
518 break;
519
520 case ICMP_ROUTERADVERT:
521 {
522 const struct ih_rdiscovery *ihp;
523 const struct id_rdiscovery *idp;
524 u_int lifetime, num, size;
525
526 (void)snprintf(buf, sizeof(buf), "router advertisement");
527 cp = buf + strlen(buf);
528
529 ihp = (const struct ih_rdiscovery *)&dp->icmp_void;
530 ND_TCHECK_SIZE(ihp);
531 (void)strncpy(cp, " lifetime ", sizeof(buf) - (cp - buf));
532 cp = buf + strlen(buf);
533 lifetime = GET_BE_U_2(ihp->ird_lifetime);
534 if (lifetime < 60) {
535 (void)snprintf(cp, sizeof(buf) - (cp - buf), "%u",
536 lifetime);
537 } else if (lifetime < 60 * 60) {
538 (void)snprintf(cp, sizeof(buf) - (cp - buf), "%u:%02u",
539 lifetime / 60, lifetime % 60);
540 } else {
541 (void)snprintf(cp, sizeof(buf) - (cp - buf),
542 "%u:%02u:%02u",
543 lifetime / 3600,
544 (lifetime % 3600) / 60,
545 lifetime % 60);
546 }
547 cp = buf + strlen(buf);
548
549 num = GET_U_1(ihp->ird_addrnum);
550 (void)snprintf(cp, sizeof(buf) - (cp - buf), " %u:", num);
551 cp = buf + strlen(buf);
552
553 size = GET_U_1(ihp->ird_addrsiz);
554 if (size != 2) {
555 (void)snprintf(cp, sizeof(buf) - (cp - buf),
556 " [size %u]", size);
557 break;
558 }
559 idp = (const struct id_rdiscovery *)&dp->icmp_data;
560 while (num > 0) {
561 ND_TCHECK_SIZE(idp);
562 (void)snprintf(cp, sizeof(buf) - (cp - buf), " {%s %u}",
563 GET_IPADDR_STRING(idp->ird_addr),
564 GET_BE_U_4(idp->ird_pref));
565 cp = buf + strlen(buf);
566 ++idp;
567 num--;
568 }
569 }
570 break;
571
572 case ICMP_TIMXCEED:
573 ND_TCHECK_4(dp->icmp_ip.ip_dst);
574 switch (icmp_code) {
575
576 case ICMP_TIMXCEED_INTRANS:
577 str = "time exceeded in-transit";
578 break;
579
580 case ICMP_TIMXCEED_REASS:
581 str = "ip reassembly time exceeded";
582 break;
583
584 default:
585 (void)snprintf(buf, sizeof(buf), "time exceeded-#%u",
586 icmp_code);
587 break;
588 }
589 break;
590
591 case ICMP_PARAMPROB:
592 if (icmp_code)
593 (void)snprintf(buf, sizeof(buf),
594 "parameter problem - code %u", icmp_code);
595 else {
596 (void)snprintf(buf, sizeof(buf),
597 "parameter problem - octet %u",
598 GET_U_1(dp->icmp_pptr));
599 }
600 break;
601
602 case ICMP_MASKREPLY:
603 (void)snprintf(buf, sizeof(buf), "address mask is 0x%08x",
604 GET_BE_U_4(dp->icmp_mask));
605 break;
606
607 case ICMP_TSTAMP:
608 (void)snprintf(buf, sizeof(buf),
609 "time stamp query id %u seq %u",
610 GET_BE_U_2(dp->icmp_id),
611 GET_BE_U_2(dp->icmp_seq));
612 break;
613
614 case ICMP_TSTAMPREPLY:
615 ND_TCHECK_4(dp->icmp_ttime);
616 (void)snprintf(buf, sizeof(buf),
617 "time stamp reply id %u seq %u: org %s",
618 GET_BE_U_2(dp->icmp_id),
619 GET_BE_U_2(dp->icmp_seq),
620 icmp_tstamp_print(GET_BE_U_4(dp->icmp_otime)));
621
622 (void)snprintf(buf+strlen(buf),sizeof(buf)-strlen(buf),", recv %s",
623 icmp_tstamp_print(GET_BE_U_4(dp->icmp_rtime)));
624 (void)snprintf(buf+strlen(buf),sizeof(buf)-strlen(buf),", xmit %s",
625 icmp_tstamp_print(GET_BE_U_4(dp->icmp_ttime)));
626 break;
627
628 default:
629 str = tok2str(icmp2str, "type-#%u", icmp_type);
630 break;
631 }
632 ND_PRINT("ICMP %s, length %u", str, plen);
633 if (ndo->ndo_vflag && !fragmented) { /* don't attempt checksumming if this is a frag */
634 if (ND_TTEST_LEN(bp, plen)) {
635 uint16_t sum;
636
637 vec[0].ptr = (const uint8_t *)(const void *)dp;
638 vec[0].len = plen;
639 sum = in_cksum(vec, 1);
640 if (sum != 0) {
641 uint16_t icmp_sum = GET_BE_U_2(dp->icmp_cksum);
642 ND_PRINT(" (wrong icmp cksum %x (->%x)!)",
643 icmp_sum,
644 in_cksum_shouldbe(icmp_sum, sum));
645 }
646 }
647 }
648
649 /*
650 * print the remnants of the IP packet.
651 * save the snaplength as this may get overidden in the IP printer.
652 */
653 if (ndo->ndo_vflag >= 1 && ICMP_ERRTYPE(icmp_type)) {
654 bp += 8;
655 ND_PRINT("\n\t");
656 ip = (const struct ip *)bp;
657 snapend_save = ndo->ndo_snapend;
658 ip_print(ndo, bp, GET_BE_U_2(ip->ip_len));
659 ndo->ndo_snapend = snapend_save;
660 }
661
662 /* ndo_protocol reassignment after ip_print() call */
663 ndo->ndo_protocol = "icmp";
664
665 /*
666 * Attempt to decode the MPLS extensions only for some ICMP types.
667 */
668 if (ndo->ndo_vflag >= 1 && plen > ICMP_EXTD_MINLEN && ICMP_MPLS_EXT_TYPE(icmp_type)) {
669
670 ND_TCHECK_SIZE(ext_dp);
671
672 /*
673 * Check first if the mpls extension header shows a non-zero length.
674 * If the length field is not set then silently verify the checksum
675 * to check if an extension header is present. This is expedient,
676 * however not all implementations set the length field proper.
677 */
678 if (GET_U_1(ext_dp->icmp_length) == 0 &&
679 ND_TTEST_LEN(ext_dp->icmp_ext_version_res, plen - ICMP_EXTD_MINLEN)) {
680 vec[0].ptr = (const uint8_t *)(const void *)&ext_dp->icmp_ext_version_res;
681 vec[0].len = plen - ICMP_EXTD_MINLEN;
682 if (in_cksum(vec, 1)) {
683 return;
684 }
685 }
686
687 ND_PRINT("\n\tMPLS extension v%u",
688 ICMP_MPLS_EXT_EXTRACT_VERSION(*(ext_dp->icmp_ext_version_res)));
689
690 /*
691 * Sanity checking of the header.
692 */
693 if (ICMP_MPLS_EXT_EXTRACT_VERSION(*(ext_dp->icmp_ext_version_res)) !=
694 ICMP_MPLS_EXT_VERSION) {
695 ND_PRINT(" packet not supported");
696 return;
697 }
698
699 hlen = plen - ICMP_EXTD_MINLEN;
700 if (ND_TTEST_LEN(ext_dp->icmp_ext_version_res, hlen)) {
701 vec[0].ptr = (const uint8_t *)(const void *)&ext_dp->icmp_ext_version_res;
702 vec[0].len = hlen;
703 ND_PRINT(", checksum 0x%04x (%scorrect), length %u",
704 GET_BE_U_2(ext_dp->icmp_ext_checksum),
705 in_cksum(vec, 1) ? "in" : "",
706 hlen);
707 }
708
709 hlen -= 4; /* subtract common header size */
710 obj_tptr = (const uint8_t *)ext_dp->icmp_ext_data;
711
712 while (hlen > sizeof(struct icmp_mpls_ext_object_header_t)) {
713
714 icmp_mpls_ext_object_header = (const struct icmp_mpls_ext_object_header_t *)obj_tptr;
715 ND_TCHECK_SIZE(icmp_mpls_ext_object_header);
716 obj_tlen = GET_BE_U_2(icmp_mpls_ext_object_header->length);
717 obj_class_num = GET_U_1(icmp_mpls_ext_object_header->class_num);
718 obj_ctype = GET_U_1(icmp_mpls_ext_object_header->ctype);
719 obj_tptr += sizeof(struct icmp_mpls_ext_object_header_t);
720
721 ND_PRINT("\n\t %s Object (%u), Class-Type: %u, length %u",
722 tok2str(icmp_mpls_ext_obj_values,"unknown",obj_class_num),
723 obj_class_num,
724 obj_ctype,
725 obj_tlen);
726
727 hlen-=sizeof(struct icmp_mpls_ext_object_header_t); /* length field includes tlv header */
728
729 /* infinite loop protection */
730 if ((obj_class_num == 0) ||
731 (obj_tlen < sizeof(struct icmp_mpls_ext_object_header_t))) {
732 return;
733 }
734 obj_tlen-=sizeof(struct icmp_mpls_ext_object_header_t);
735
736 switch (obj_class_num) {
737 case 1:
738 switch(obj_ctype) {
739 case 1:
740 raw_label = GET_BE_U_4(obj_tptr);
741 ND_PRINT("\n\t label %u, exp %u", MPLS_LABEL(raw_label), MPLS_EXP(raw_label));
742 if (MPLS_STACK(raw_label))
743 ND_PRINT(", [S]");
744 ND_PRINT(", ttl %u", MPLS_TTL(raw_label));
745 break;
746 default:
747 print_unknown_data(ndo, obj_tptr, "\n\t ", obj_tlen);
748 }
749 break;
750
751 /*
752 * FIXME those are the defined objects that lack a decoder
753 * you are welcome to contribute code ;-)
754 */
755 case 2:
756 default:
757 print_unknown_data(ndo, obj_tptr, "\n\t ", obj_tlen);
758 break;
759 }
760 if (hlen < obj_tlen)
761 break;
762 hlen -= obj_tlen;
763 obj_tptr += obj_tlen;
764 }
765 }
766
767 return;
768 trunc:
769 nd_print_trunc(ndo);
770 }
[mirror] the TCPdump network dissector