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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 /* Formats for most of the ICMP_UNREACH codes */
206 static const struct tok unreach2str[] = {
207 { ICMP_UNREACH_NET, "net %s unreachable" },
208 { ICMP_UNREACH_HOST, "host %s unreachable" },
209 { ICMP_UNREACH_SRCFAIL,
210 "%s unreachable - source route failed" },
211 { ICMP_UNREACH_NET_UNKNOWN, "net %s unreachable - unknown" },
212 { ICMP_UNREACH_HOST_UNKNOWN, "host %s unreachable - unknown" },
213 { ICMP_UNREACH_ISOLATED,
214 "%s unreachable - source host isolated" },
215 { ICMP_UNREACH_NET_PROHIB,
216 "net %s unreachable - admin prohibited" },
217 { ICMP_UNREACH_HOST_PROHIB,
218 "host %s unreachable - admin prohibited" },
219 { ICMP_UNREACH_TOSNET,
220 "net %s unreachable - tos prohibited" },
221 { ICMP_UNREACH_TOSHOST,
222 "host %s unreachable - tos prohibited" },
223 { ICMP_UNREACH_FILTER_PROHIB,
224 "host %s unreachable - admin prohibited filter" },
225 { ICMP_UNREACH_HOST_PRECEDENCE,
226 "host %s unreachable - host precedence violation" },
227 { ICMP_UNREACH_PRECEDENCE_CUTOFF,
228 "host %s unreachable - precedence cutoff" },
229 { 0, NULL }
230 };
231
232 /* Formats for the ICMP_REDIRECT codes */
233 static const struct tok type2str[] = {
234 { ICMP_REDIRECT_NET, "redirect %s to net %s" },
235 { ICMP_REDIRECT_HOST, "redirect %s to host %s" },
236 { ICMP_REDIRECT_TOSNET, "redirect-tos %s to net %s" },
237 { ICMP_REDIRECT_TOSHOST, "redirect-tos %s to host %s" },
238 { 0, NULL }
239 };
240
241 /* rfc1191 */
242 struct mtu_discovery {
243 nd_uint16_t unused;
244 nd_uint16_t nexthopmtu;
245 };
246
247 /* rfc1256 */
248 struct ih_rdiscovery {
249 nd_uint8_t ird_addrnum;
250 nd_uint8_t ird_addrsiz;
251 nd_uint16_t ird_lifetime;
252 };
253
254 struct id_rdiscovery {
255 nd_uint32_t ird_addr;
256 nd_uint32_t ird_pref;
257 };
258
259 /*
260 * draft-bonica-internet-icmp-08
261 *
262 * The Destination Unreachable, Time Exceeded
263 * and Parameter Problem messages are slightly changed as per
264 * the above draft. A new Length field gets added to give
265 * the caller an idea about the length of the piggypacked
266 * IP packet before the MPLS extension header starts.
267 *
268 * The Length field represents length of the padded "original datagram"
269 * field measured in 32-bit words.
270 *
271 * 0 1 2 3
272 * 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
273 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
274 * | Type | Code | Checksum |
275 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
276 * | unused | Length | unused |
277 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
278 * | Internet Header + leading octets of original datagram |
279 * | |
280 * | // |
281 * | |
282 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
283 */
284
285 struct icmp_ext_t {
286 nd_uint8_t icmp_type;
287 nd_uint8_t icmp_code;
288 nd_uint16_t icmp_checksum;
289 nd_byte icmp_reserved;
290 nd_uint8_t icmp_length;
291 nd_byte icmp_reserved2[2];
292 nd_byte icmp_ext_legacy_header[128]; /* extension header starts 128 bytes after ICMP header */
293 nd_byte icmp_ext_version_res[2];
294 nd_uint16_t icmp_ext_checksum;
295 nd_byte icmp_ext_data[1];
296 };
297
298 struct icmp_mpls_ext_object_header_t {
299 nd_uint16_t length;
300 nd_uint8_t class_num;
301 nd_uint8_t ctype;
302 };
303
304 static const struct tok icmp_mpls_ext_obj_values[] = {
305 { 1, "MPLS Stack Entry" },
306 { 2, "Extended Payload" },
307 { 0, NULL}
308 };
309
310 /* prototypes */
311 const char *icmp_tstamp_print(u_int);
312
313 /* print the milliseconds since midnight UTC */
314 const char *
315 icmp_tstamp_print(u_int tstamp)
316 {
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 nd_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 uint8_t icmp_type, icmp_code;
336 const struct icmp_ext_t *ext_dp;
337 const struct ip *ip;
338 const char *str, *fmt;
339 const struct ip *oip;
340 uint8_t ip_proto;
341 const struct udphdr *ouh;
342 const uint8_t *obj_tptr;
343 uint32_t raw_label;
344 const u_char *snapend_save;
345 const struct icmp_mpls_ext_object_header_t *icmp_mpls_ext_object_header;
346 u_int hlen, mtu, obj_tlen, obj_class_num, obj_ctype;
347 uint16_t dport;
348 char buf[MAXHOSTNAMELEN + 100];
349 struct cksum_vec vec[1];
350
351 ndo->ndo_protocol = "icmp";
352 dp = (const struct icmp *)bp;
353 ext_dp = (const struct icmp_ext_t *)bp;
354 ip = (const struct ip *)bp2;
355 str = buf;
356
357 ND_TCHECK_1(dp->icmp_code);
358 icmp_type = GET_U_1(dp->icmp_type);
359 icmp_code = GET_U_1(dp->icmp_code);
360 switch (icmp_type) {
361
362 case ICMP_ECHO:
363 case ICMP_ECHOREPLY:
364 ND_TCHECK_2(dp->icmp_seq);
365 (void)nd_snprintf(buf, sizeof(buf), "echo %s, id %u, seq %u",
366 icmp_type == ICMP_ECHO ?
367 "request" : "reply",
368 GET_BE_U_2(dp->icmp_id),
369 GET_BE_U_2(dp->icmp_seq));
370 break;
371
372 case ICMP_UNREACH:
373 ND_TCHECK_4(dp->icmp_ip.ip_dst);
374 switch (icmp_code) {
375
376 case ICMP_UNREACH_PROTOCOL:
377 ND_TCHECK_1(dp->icmp_ip.ip_p);
378 (void)nd_snprintf(buf, sizeof(buf),
379 "%s protocol %u unreachable",
380 ipaddr_string(ndo, dp->icmp_ip.ip_dst),
381 GET_U_1(dp->icmp_ip.ip_p));
382 break;
383
384 case ICMP_UNREACH_PORT:
385 ND_TCHECK_1(dp->icmp_ip.ip_p);
386 oip = &dp->icmp_ip;
387 hlen = IP_HL(oip) * 4;
388 ouh = (const struct udphdr *)(((const u_char *)oip) + hlen);
389 ND_TCHECK_2(ouh->uh_dport);
390 dport = GET_BE_U_2(ouh->uh_dport);
391 ip_proto = GET_U_1(oip->ip_p);
392 switch (ip_proto) {
393
394 case IPPROTO_TCP:
395 (void)nd_snprintf(buf, sizeof(buf),
396 "%s tcp port %s unreachable",
397 ipaddr_string(ndo, oip->ip_dst),
398 tcpport_string(ndo, dport));
399 break;
400
401 case IPPROTO_UDP:
402 (void)nd_snprintf(buf, sizeof(buf),
403 "%s udp port %s unreachable",
404 ipaddr_string(ndo, oip->ip_dst),
405 udpport_string(ndo, dport));
406 break;
407
408 default:
409 (void)nd_snprintf(buf, sizeof(buf),
410 "%s protocol %u port %u unreachable",
411 ipaddr_string(ndo, oip->ip_dst),
412 ip_proto, dport);
413 break;
414 }
415 break;
416
417 case ICMP_UNREACH_NEEDFRAG:
418 {
419 const struct mtu_discovery *mp;
420 mp = (const struct mtu_discovery *)(const u_char *)&dp->icmp_void;
421 mtu = GET_BE_U_2(mp->nexthopmtu);
422 if (mtu) {
423 (void)nd_snprintf(buf, sizeof(buf),
424 "%s unreachable - need to frag (mtu %u)",
425 ipaddr_string(ndo, dp->icmp_ip.ip_dst), mtu);
426 } else {
427 (void)nd_snprintf(buf, sizeof(buf),
428 "%s unreachable - need to frag",
429 ipaddr_string(ndo, dp->icmp_ip.ip_dst));
430 }
431 }
432 break;
433
434 default:
435 fmt = tok2str(unreach2str, "#%u %%s unreachable",
436 icmp_code);
437 (void)nd_snprintf(buf, sizeof(buf), fmt,
438 ipaddr_string(ndo, dp->icmp_ip.ip_dst));
439 break;
440 }
441 break;
442
443 case ICMP_REDIRECT:
444 ND_TCHECK_4(dp->icmp_ip.ip_dst);
445 fmt = tok2str(type2str, "redirect-#%u %%s to net %%s",
446 icmp_code);
447 (void)nd_snprintf(buf, sizeof(buf), fmt,
448 ipaddr_string(ndo, dp->icmp_ip.ip_dst),
449 ipaddr_string(ndo, dp->icmp_gwaddr));
450 break;
451
452 case ICMP_ROUTERADVERT:
453 {
454 const struct ih_rdiscovery *ihp;
455 const struct id_rdiscovery *idp;
456 u_int lifetime, num, size;
457
458 (void)nd_snprintf(buf, sizeof(buf), "router advertisement");
459 cp = buf + strlen(buf);
460
461 ihp = (const struct ih_rdiscovery *)&dp->icmp_void;
462 ND_TCHECK_SIZE(ihp);
463 (void)strncpy(cp, " lifetime ", sizeof(buf) - (cp - buf));
464 cp = buf + strlen(buf);
465 lifetime = GET_BE_U_2(ihp->ird_lifetime);
466 if (lifetime < 60) {
467 (void)nd_snprintf(cp, sizeof(buf) - (cp - buf), "%u",
468 lifetime);
469 } else if (lifetime < 60 * 60) {
470 (void)nd_snprintf(cp, sizeof(buf) - (cp - buf), "%u:%02u",
471 lifetime / 60, lifetime % 60);
472 } else {
473 (void)nd_snprintf(cp, sizeof(buf) - (cp - buf),
474 "%u:%02u:%02u",
475 lifetime / 3600,
476 (lifetime % 3600) / 60,
477 lifetime % 60);
478 }
479 cp = buf + strlen(buf);
480
481 num = GET_U_1(ihp->ird_addrnum);
482 (void)nd_snprintf(cp, sizeof(buf) - (cp - buf), " %u:", num);
483 cp = buf + strlen(buf);
484
485 size = GET_U_1(ihp->ird_addrsiz);
486 if (size != 2) {
487 (void)nd_snprintf(cp, sizeof(buf) - (cp - buf),
488 " [size %u]", size);
489 break;
490 }
491 idp = (const struct id_rdiscovery *)&dp->icmp_data;
492 while (num > 0) {
493 ND_TCHECK_SIZE(idp);
494 (void)nd_snprintf(cp, sizeof(buf) - (cp - buf), " {%s %u}",
495 ipaddr_string(ndo, idp->ird_addr),
496 GET_BE_U_4(idp->ird_pref));
497 cp = buf + strlen(buf);
498 ++idp;
499 num--;
500 }
501 }
502 break;
503
504 case ICMP_TIMXCEED:
505 ND_TCHECK_4(dp->icmp_ip.ip_dst);
506 switch (icmp_code) {
507
508 case ICMP_TIMXCEED_INTRANS:
509 str = "time exceeded in-transit";
510 break;
511
512 case ICMP_TIMXCEED_REASS:
513 str = "ip reassembly time exceeded";
514 break;
515
516 default:
517 (void)nd_snprintf(buf, sizeof(buf), "time exceeded-#%u",
518 icmp_code);
519 break;
520 }
521 break;
522
523 case ICMP_PARAMPROB:
524 if (icmp_code)
525 (void)nd_snprintf(buf, sizeof(buf),
526 "parameter problem - code %u", icmp_code);
527 else {
528 ND_TCHECK_1(dp->icmp_pptr);
529 (void)nd_snprintf(buf, sizeof(buf),
530 "parameter problem - octet %u",
531 GET_U_1(dp->icmp_pptr));
532 }
533 break;
534
535 case ICMP_MASKREPLY:
536 ND_TCHECK_4(dp->icmp_mask);
537 (void)nd_snprintf(buf, sizeof(buf), "address mask is 0x%08x",
538 GET_BE_U_4(dp->icmp_mask));
539 break;
540
541 case ICMP_TSTAMP:
542 ND_TCHECK_2(dp->icmp_seq);
543 (void)nd_snprintf(buf, sizeof(buf),
544 "time stamp query id %u seq %u",
545 GET_BE_U_2(dp->icmp_id),
546 GET_BE_U_2(dp->icmp_seq));
547 break;
548
549 case ICMP_TSTAMPREPLY:
550 ND_TCHECK_4(dp->icmp_ttime);
551 (void)nd_snprintf(buf, sizeof(buf),
552 "time stamp reply id %u seq %u: org %s",
553 GET_BE_U_2(dp->icmp_id),
554 GET_BE_U_2(dp->icmp_seq),
555 icmp_tstamp_print(GET_BE_U_4(dp->icmp_otime)));
556
557 (void)nd_snprintf(buf+strlen(buf),sizeof(buf)-strlen(buf),", recv %s",
558 icmp_tstamp_print(GET_BE_U_4(dp->icmp_rtime)));
559 (void)nd_snprintf(buf+strlen(buf),sizeof(buf)-strlen(buf),", xmit %s",
560 icmp_tstamp_print(GET_BE_U_4(dp->icmp_ttime)));
561 break;
562
563 default:
564 str = tok2str(icmp2str, "type-#%u", icmp_type);
565 break;
566 }
567 ND_PRINT("ICMP %s, length %u", str, plen);
568 if (ndo->ndo_vflag && !fragmented) { /* don't attempt checksumming if this is a frag */
569 if (ND_TTEST_LEN(bp, plen)) {
570 uint16_t sum;
571
572 vec[0].ptr = (const uint8_t *)(const void *)dp;
573 vec[0].len = plen;
574 sum = in_cksum(vec, 1);
575 if (sum != 0) {
576 uint16_t icmp_sum = GET_BE_U_2(dp->icmp_cksum);
577 ND_PRINT(" (wrong icmp cksum %x (->%x)!)",
578 icmp_sum,
579 in_cksum_shouldbe(icmp_sum, sum));
580 }
581 }
582 }
583
584 /*
585 * print the remnants of the IP packet.
586 * save the snaplength as this may get overidden in the IP printer.
587 */
588 if (ndo->ndo_vflag >= 1 && ICMP_ERRTYPE(icmp_type)) {
589 bp += 8;
590 ND_PRINT("\n\t");
591 ip = (const struct ip *)bp;
592 snapend_save = ndo->ndo_snapend;
593 ND_TCHECK_2(ip->ip_len);
594 ip_print(ndo, bp, GET_BE_U_2(ip->ip_len));
595 ndo->ndo_snapend = snapend_save;
596 }
597
598 /* ndo_protocol reassignment after ip_print() call */
599 ndo->ndo_protocol = "icmp";
600
601 /*
602 * Attempt to decode the MPLS extensions only for some ICMP types.
603 */
604 if (ndo->ndo_vflag >= 1 && plen > ICMP_EXTD_MINLEN && ICMP_MPLS_EXT_TYPE(icmp_type)) {
605
606 ND_TCHECK_SIZE(ext_dp);
607
608 /*
609 * Check first if the mpls extension header shows a non-zero length.
610 * If the length field is not set then silently verify the checksum
611 * to check if an extension header is present. This is expedient,
612 * however not all implementations set the length field proper.
613 */
614 if (GET_U_1(ext_dp->icmp_length) == 0 &&
615 ND_TTEST_LEN(ext_dp->icmp_ext_version_res, plen - ICMP_EXTD_MINLEN)) {
616 vec[0].ptr = (const uint8_t *)(const void *)&ext_dp->icmp_ext_version_res;
617 vec[0].len = plen - ICMP_EXTD_MINLEN;
618 if (in_cksum(vec, 1)) {
619 return;
620 }
621 }
622
623 ND_PRINT("\n\tMPLS extension v%u",
624 ICMP_MPLS_EXT_EXTRACT_VERSION(*(ext_dp->icmp_ext_version_res)));
625
626 /*
627 * Sanity checking of the header.
628 */
629 if (ICMP_MPLS_EXT_EXTRACT_VERSION(*(ext_dp->icmp_ext_version_res)) !=
630 ICMP_MPLS_EXT_VERSION) {
631 ND_PRINT(" packet not supported");
632 return;
633 }
634
635 hlen = plen - ICMP_EXTD_MINLEN;
636 if (ND_TTEST_LEN(ext_dp->icmp_ext_version_res, hlen)) {
637 vec[0].ptr = (const uint8_t *)(const void *)&ext_dp->icmp_ext_version_res;
638 vec[0].len = hlen;
639 ND_PRINT(", checksum 0x%04x (%scorrect), length %u",
640 GET_BE_U_2(ext_dp->icmp_ext_checksum),
641 in_cksum(vec, 1) ? "in" : "",
642 hlen);
643 }
644
645 hlen -= 4; /* subtract common header size */
646 obj_tptr = (const uint8_t *)ext_dp->icmp_ext_data;
647
648 while (hlen > sizeof(struct icmp_mpls_ext_object_header_t)) {
649
650 icmp_mpls_ext_object_header = (const struct icmp_mpls_ext_object_header_t *)obj_tptr;
651 ND_TCHECK_SIZE(icmp_mpls_ext_object_header);
652 obj_tlen = GET_BE_U_2(icmp_mpls_ext_object_header->length);
653 obj_class_num = GET_U_1(icmp_mpls_ext_object_header->class_num);
654 obj_ctype = GET_U_1(icmp_mpls_ext_object_header->ctype);
655 obj_tptr += sizeof(struct icmp_mpls_ext_object_header_t);
656
657 ND_PRINT("\n\t %s Object (%u), Class-Type: %u, length %u",
658 tok2str(icmp_mpls_ext_obj_values,"unknown",obj_class_num),
659 obj_class_num,
660 obj_ctype,
661 obj_tlen);
662
663 hlen-=sizeof(struct icmp_mpls_ext_object_header_t); /* length field includes tlv header */
664
665 /* infinite loop protection */
666 if ((obj_class_num == 0) ||
667 (obj_tlen < sizeof(struct icmp_mpls_ext_object_header_t))) {
668 return;
669 }
670 obj_tlen-=sizeof(struct icmp_mpls_ext_object_header_t);
671
672 switch (obj_class_num) {
673 case 1:
674 switch(obj_ctype) {
675 case 1:
676 ND_TCHECK_4(obj_tptr);
677 raw_label = GET_BE_U_4(obj_tptr);
678 ND_PRINT("\n\t label %u, exp %u", MPLS_LABEL(raw_label), MPLS_EXP(raw_label));
679 if (MPLS_STACK(raw_label))
680 ND_PRINT(", [S]");
681 ND_PRINT(", ttl %u", MPLS_TTL(raw_label));
682 break;
683 default:
684 print_unknown_data(ndo, obj_tptr, "\n\t ", obj_tlen);
685 }
686 break;
687
688 /*
689 * FIXME those are the defined objects that lack a decoder
690 * you are welcome to contribute code ;-)
691 */
692 case 2:
693 default:
694 print_unknown_data(ndo, obj_tptr, "\n\t ", obj_tlen);
695 break;
696 }
697 if (hlen < obj_tlen)
698 break;
699 hlen -= obj_tlen;
700 obj_tptr += obj_tlen;
701 }
702 }
703
704 return;
705 trunc:
706 nd_print_trunc(ndo);
707 }
[mirror] the TCPdump network dissector