tcpdump  4.99.1
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print-icmp.c
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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 {
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 {
73  } id_ts;
74  struct id_ip {
75  struct ip idi_ip;
76  /* options and then 64 bits of data */
77  } id_ip;
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 enough 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 */
209 };
210 
211 /* rfc1256 */
216 };
217 
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 piggybacked
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 {
256  nd_byte icmp_ext_legacy_header[128]; /* extension header starts 128 bytes after ICMP header */
260 };
261 
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 struct icmp_mpls_ext_object_header_t *icmp_mpls_ext_object_header;
309  u_int hlen, mtu, obj_tlen, obj_class_num, obj_ctype;
310  uint16_t dport;
311  char buf[MAXHOSTNAMELEN + 100];
312  struct cksum_vec vec[1];
313 
314  ndo->ndo_protocol = "icmp";
315  dp = (const struct icmp *)bp;
316  ext_dp = (const struct icmp_ext_t *)bp;
317  ip = (const struct ip *)bp2;
318  str = buf;
319 
320  icmp_type = GET_U_1(dp->icmp_type);
321  icmp_code = GET_U_1(dp->icmp_code);
322  switch (icmp_type) {
323 
324  case ICMP_ECHO:
325  case ICMP_ECHOREPLY:
326  (void)snprintf(buf, sizeof(buf), "echo %s, id %u, seq %u",
327  icmp_type == ICMP_ECHO ?
328  "request" : "reply",
329  GET_BE_U_2(dp->icmp_id),
330  GET_BE_U_2(dp->icmp_seq));
331  break;
332 
333  case ICMP_UNREACH:
334  switch (icmp_code) {
335 
336  case ICMP_UNREACH_NET:
337  (void)snprintf(buf, sizeof(buf),
338  "net %s unreachable",
339  GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
340  break;
341 
342  case ICMP_UNREACH_HOST:
343  (void)snprintf(buf, sizeof(buf),
344  "host %s unreachable",
345  GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
346  break;
347 
349  (void)snprintf(buf, sizeof(buf),
350  "%s protocol %u unreachable",
351  GET_IPADDR_STRING(dp->icmp_ip.ip_dst),
352  GET_U_1(dp->icmp_ip.ip_p));
353  break;
354 
355  case ICMP_UNREACH_PORT:
356  ND_TCHECK_1(dp->icmp_ip.ip_p);
357  oip = &dp->icmp_ip;
358  hlen = IP_HL(oip) * 4;
359  ouh = (const struct udphdr *)(((const u_char *)oip) + hlen);
360  dport = GET_BE_U_2(ouh->uh_dport);
361  ip_proto = GET_U_1(oip->ip_p);
362  switch (ip_proto) {
363 
364  case IPPROTO_TCP:
365  (void)snprintf(buf, sizeof(buf),
366  "%s tcp port %s unreachable",
367  GET_IPADDR_STRING(oip->ip_dst),
368  tcpport_string(ndo, dport));
369  break;
370 
371  case IPPROTO_UDP:
372  (void)snprintf(buf, sizeof(buf),
373  "%s udp port %s unreachable",
374  GET_IPADDR_STRING(oip->ip_dst),
375  udpport_string(ndo, dport));
376  break;
377 
378  default:
379  (void)snprintf(buf, sizeof(buf),
380  "%s protocol %u port %u unreachable",
381  GET_IPADDR_STRING(oip->ip_dst),
382  ip_proto, dport);
383  break;
384  }
385  break;
386 
388  {
389  const struct mtu_discovery *mp;
390  mp = (const struct mtu_discovery *)(const u_char *)&dp->icmp_void;
391  mtu = GET_BE_U_2(mp->nexthopmtu);
392  if (mtu) {
393  (void)snprintf(buf, sizeof(buf),
394  "%s unreachable - need to frag (mtu %u)",
395  GET_IPADDR_STRING(dp->icmp_ip.ip_dst), mtu);
396  } else {
397  (void)snprintf(buf, sizeof(buf),
398  "%s unreachable - need to frag",
399  GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
400  }
401  }
402  break;
403 
405  (void)snprintf(buf, sizeof(buf),
406  "%s unreachable - source route failed",
407  GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
408  break;
409 
411  (void)snprintf(buf, sizeof(buf),
412  "net %s unreachable - unknown",
413  GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
414  break;
415 
417  (void)snprintf(buf, sizeof(buf),
418  "host %s unreachable - unknown",
419  GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
420  break;
421 
423  (void)snprintf(buf, sizeof(buf),
424  "%s unreachable - source host isolated",
425  GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
426  break;
427 
429  (void)snprintf(buf, sizeof(buf),
430  "net %s unreachable - admin prohibited",
431  GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
432  break;
433 
435  (void)snprintf(buf, sizeof(buf),
436  "host %s unreachable - admin prohibited",
437  GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
438  break;
439 
440  case ICMP_UNREACH_TOSNET:
441  (void)snprintf(buf, sizeof(buf),
442  "net %s unreachable - tos prohibited",
443  GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
444  break;
445 
447  (void)snprintf(buf, sizeof(buf),
448  "host %s unreachable - tos prohibited",
449  GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
450  break;
451 
453  (void)snprintf(buf, sizeof(buf),
454  "host %s unreachable - admin prohibited filter",
455  GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
456  break;
457 
459  (void)snprintf(buf, sizeof(buf),
460  "host %s unreachable - host precedence violation",
461  GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
462  break;
463 
465  (void)snprintf(buf, sizeof(buf),
466  "host %s unreachable - precedence cutoff",
467  GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
468  break;
469 
470  default:
471  (void)snprintf(buf, sizeof(buf),
472  "%s unreachable - #%u",
473  GET_IPADDR_STRING(dp->icmp_ip.ip_dst),
474  icmp_code);
475  break;
476  }
477  break;
478 
479  case ICMP_REDIRECT:
480  switch (icmp_code) {
481 
482  case ICMP_REDIRECT_NET:
483  (void)snprintf(buf, sizeof(buf),
484  "redirect %s to net %s",
485  GET_IPADDR_STRING(dp->icmp_ip.ip_dst),
486  GET_IPADDR_STRING(dp->icmp_gwaddr));
487  break;
488 
489  case ICMP_REDIRECT_HOST:
490  (void)snprintf(buf, sizeof(buf),
491  "redirect %s to host %s",
492  GET_IPADDR_STRING(dp->icmp_ip.ip_dst),
493  GET_IPADDR_STRING(dp->icmp_gwaddr));
494  break;
495 
497  (void)snprintf(buf, sizeof(buf),
498  "redirect-tos %s to net %s",
499  GET_IPADDR_STRING(dp->icmp_ip.ip_dst),
500  GET_IPADDR_STRING(dp->icmp_gwaddr));
501  break;
502 
504  (void)snprintf(buf, sizeof(buf),
505  "redirect-tos %s to host %s",
506  GET_IPADDR_STRING(dp->icmp_ip.ip_dst),
507  GET_IPADDR_STRING(dp->icmp_gwaddr));
508  break;
509 
510  default:
511  (void)snprintf(buf, sizeof(buf),
512  "redirect-#%u %s to %s", icmp_code,
513  GET_IPADDR_STRING(dp->icmp_ip.ip_dst),
514  GET_IPADDR_STRING(dp->icmp_gwaddr));
515  break;
516  }
517  break;
518 
519  case ICMP_ROUTERADVERT:
520  {
521  const struct ih_rdiscovery *ihp;
522  const struct id_rdiscovery *idp;
523  u_int lifetime, num, size;
524 
525  (void)snprintf(buf, sizeof(buf), "router advertisement");
526  cp = buf + strlen(buf);
527 
528  ihp = (const struct ih_rdiscovery *)&dp->icmp_void;
529  ND_TCHECK_SIZE(ihp);
530  (void)strncpy(cp, " lifetime ", sizeof(buf) - (cp - buf));
531  cp = buf + strlen(buf);
532  lifetime = GET_BE_U_2(ihp->ird_lifetime);
533  if (lifetime < 60) {
534  (void)snprintf(cp, sizeof(buf) - (cp - buf), "%u",
535  lifetime);
536  } else if (lifetime < 60 * 60) {
537  (void)snprintf(cp, sizeof(buf) - (cp - buf), "%u:%02u",
538  lifetime / 60, lifetime % 60);
539  } else {
540  (void)snprintf(cp, sizeof(buf) - (cp - buf),
541  "%u:%02u:%02u",
542  lifetime / 3600,
543  (lifetime % 3600) / 60,
544  lifetime % 60);
545  }
546  cp = buf + strlen(buf);
547 
548  num = GET_U_1(ihp->ird_addrnum);
549  (void)snprintf(cp, sizeof(buf) - (cp - buf), " %u:", num);
550  cp = buf + strlen(buf);
551 
552  size = GET_U_1(ihp->ird_addrsiz);
553  if (size != 2) {
554  (void)snprintf(cp, sizeof(buf) - (cp - buf),
555  " [size %u]", size);
556  break;
557  }
558  idp = (const struct id_rdiscovery *)&dp->icmp_data;
559  while (num > 0) {
560  ND_TCHECK_SIZE(idp);
561  (void)snprintf(cp, sizeof(buf) - (cp - buf), " {%s %u}",
563  GET_BE_U_4(idp->ird_pref));
564  cp = buf + strlen(buf);
565  ++idp;
566  num--;
567  }
568  }
569  break;
570 
571  case ICMP_TIMXCEED:
572  ND_TCHECK_4(dp->icmp_ip.ip_dst);
573  switch (icmp_code) {
574 
576  str = "time exceeded in-transit";
577  break;
578 
579  case ICMP_TIMXCEED_REASS:
580  str = "ip reassembly time exceeded";
581  break;
582 
583  default:
584  (void)snprintf(buf, sizeof(buf), "time exceeded-#%u",
585  icmp_code);
586  break;
587  }
588  break;
589 
590  case ICMP_PARAMPROB:
591  if (icmp_code)
592  (void)snprintf(buf, sizeof(buf),
593  "parameter problem - code %u", icmp_code);
594  else {
595  (void)snprintf(buf, sizeof(buf),
596  "parameter problem - octet %u",
597  GET_U_1(dp->icmp_pptr));
598  }
599  break;
600 
601  case ICMP_MASKREPLY:
602  (void)snprintf(buf, sizeof(buf), "address mask is 0x%08x",
603  GET_BE_U_4(dp->icmp_mask));
604  break;
605 
606  case ICMP_TSTAMP:
607  (void)snprintf(buf, sizeof(buf),
608  "time stamp query id %u seq %u",
609  GET_BE_U_2(dp->icmp_id),
610  GET_BE_U_2(dp->icmp_seq));
611  break;
612 
613  case ICMP_TSTAMPREPLY:
614  ND_TCHECK_4(dp->icmp_ttime);
615  (void)snprintf(buf, sizeof(buf),
616  "time stamp reply id %u seq %u: org %s",
617  GET_BE_U_2(dp->icmp_id),
618  GET_BE_U_2(dp->icmp_seq),
619  icmp_tstamp_print(GET_BE_U_4(dp->icmp_otime)));
620 
621  (void)snprintf(buf+strlen(buf),sizeof(buf)-strlen(buf),", recv %s",
622  icmp_tstamp_print(GET_BE_U_4(dp->icmp_rtime)));
623  (void)snprintf(buf+strlen(buf),sizeof(buf)-strlen(buf),", xmit %s",
624  icmp_tstamp_print(GET_BE_U_4(dp->icmp_ttime)));
625  break;
626 
627  default:
628  str = tok2str(icmp2str, "type-#%u", icmp_type);
629  break;
630  }
631  ND_PRINT("ICMP %s, length %u", str, plen);
632  if (ndo->ndo_vflag && !fragmented) { /* don't attempt checksumming if this is a frag */
633  if (ND_TTEST_LEN(bp, plen)) {
634  uint16_t sum;
635 
636  vec[0].ptr = (const uint8_t *)(const void *)dp;
637  vec[0].len = plen;
638  sum = in_cksum(vec, 1);
639  if (sum != 0) {
640  uint16_t icmp_sum = GET_BE_U_2(dp->icmp_cksum);
641  ND_PRINT(" (wrong icmp cksum %x (->%x)!)",
642  icmp_sum,
643  in_cksum_shouldbe(icmp_sum, sum));
644  }
645  }
646  }
647 
648  /*
649  * print the remnants of the IP packet.
650  * save the snaplength as this may get overridden in the IP printer.
651  */
652  if (ndo->ndo_vflag >= 1 && ICMP_ERRTYPE(icmp_type)) {
653  const u_char *snapend_save;
654 
655  bp += 8;
656  ND_PRINT("\n\t");
657  ip = (const struct ip *)bp;
658  snapend_save = ndo->ndo_snapend;
659  /*
660  * Update the snapend because extensions (MPLS, ...) may be
661  * present after the IP packet. In this case the current
662  * (outer) packet's snapend is not what ip_print() needs to
663  * decode an IP packet nested in the middle of an ICMP payload.
664  *
665  * This prevents that, in ip_print(), for the nested IP packet,
666  * the remaining length < remaining caplen.
667  */
668  ndo->ndo_snapend = ND_MIN(bp + GET_BE_U_2(ip->ip_len),
669  ndo->ndo_snapend);
670  ip_print(ndo, bp, GET_BE_U_2(ip->ip_len));
671  ndo->ndo_snapend = snapend_save;
672  }
673 
674  /* ndo_protocol reassignment after ip_print() call */
675  ndo->ndo_protocol = "icmp";
676 
677  /*
678  * Attempt to decode the MPLS extensions only for some ICMP types.
679  */
680  if (ndo->ndo_vflag >= 1 && plen > ICMP_EXTD_MINLEN && ICMP_MPLS_EXT_TYPE(icmp_type)) {
681 
682  ND_TCHECK_SIZE(ext_dp);
683 
684  /*
685  * Check first if the mpls extension header shows a non-zero length.
686  * If the length field is not set then silently verify the checksum
687  * to check if an extension header is present. This is expedient,
688  * however not all implementations set the length field proper.
689  */
690  if (GET_U_1(ext_dp->icmp_length) == 0 &&
692  vec[0].ptr = (const uint8_t *)(const void *)&ext_dp->icmp_ext_version_res;
693  vec[0].len = plen - ICMP_EXTD_MINLEN;
694  if (in_cksum(vec, 1)) {
695  return;
696  }
697  }
698 
699  ND_PRINT("\n\tMPLS extension v%u",
701 
702  /*
703  * Sanity checking of the header.
704  */
707  ND_PRINT(" packet not supported");
708  return;
709  }
710 
711  hlen = plen - ICMP_EXTD_MINLEN;
712  if (ND_TTEST_LEN(ext_dp->icmp_ext_version_res, hlen)) {
713  vec[0].ptr = (const uint8_t *)(const void *)&ext_dp->icmp_ext_version_res;
714  vec[0].len = hlen;
715  ND_PRINT(", checksum 0x%04x (%scorrect), length %u",
716  GET_BE_U_2(ext_dp->icmp_ext_checksum),
717  in_cksum(vec, 1) ? "in" : "",
718  hlen);
719  }
720 
721  hlen -= 4; /* subtract common header size */
722  obj_tptr = (const uint8_t *)ext_dp->icmp_ext_data;
723 
724  while (hlen > sizeof(struct icmp_mpls_ext_object_header_t)) {
725 
726  icmp_mpls_ext_object_header = (const struct icmp_mpls_ext_object_header_t *)obj_tptr;
727  ND_TCHECK_SIZE(icmp_mpls_ext_object_header);
728  obj_tlen = GET_BE_U_2(icmp_mpls_ext_object_header->length);
729  obj_class_num = GET_U_1(icmp_mpls_ext_object_header->class_num);
730  obj_ctype = GET_U_1(icmp_mpls_ext_object_header->ctype);
731  obj_tptr += sizeof(struct icmp_mpls_ext_object_header_t);
732 
733  ND_PRINT("\n\t %s Object (%u), Class-Type: %u, length %u",
734  tok2str(icmp_mpls_ext_obj_values,"unknown",obj_class_num),
735  obj_class_num,
736  obj_ctype,
737  obj_tlen);
738 
739  hlen-=sizeof(struct icmp_mpls_ext_object_header_t); /* length field includes tlv header */
740 
741  /* infinite loop protection */
742  if ((obj_class_num == 0) ||
743  (obj_tlen < sizeof(struct icmp_mpls_ext_object_header_t))) {
744  return;
745  }
746  obj_tlen-=sizeof(struct icmp_mpls_ext_object_header_t);
747 
748  switch (obj_class_num) {
749  case 1:
750  switch(obj_ctype) {
751  case 1:
752  raw_label = GET_BE_U_4(obj_tptr);
753  ND_PRINT("\n\t label %u, exp %u", MPLS_LABEL(raw_label), MPLS_EXP(raw_label));
754  if (MPLS_STACK(raw_label))
755  ND_PRINT(", [S]");
756  ND_PRINT(", ttl %u", MPLS_TTL(raw_label));
757  break;
758  default:
759  print_unknown_data(ndo, obj_tptr, "\n\t ", obj_tlen);
760  }
761  break;
762 
763  /*
764  * FIXME those are the defined objects that lack a decoder
765  * you are welcome to contribute code ;-)
766  */
767  case 2:
768  default:
769  print_unknown_data(ndo, obj_tptr, "\n\t ", obj_tlen);
770  break;
771  }
772  if (hlen < obj_tlen)
773  break;
774  hlen -= obj_tlen;
775  obj_tptr += obj_tlen;
776  }
777  }
778 
779  return;
780 trunc:
781  nd_print_trunc(ndo);
782 }
const char * tcpport_string(netdissect_options *ndo, u_short port)
Definition: addrtoname.c:739
const char * udpport_string(netdissect_options *ndo, u_short port)
Definition: addrtoname.c:761
#define GET_IPADDR_STRING(p)
Definition: addrtoname.h:120
#define GET_BE_U_4(p)
Definition: extract.h:877
#define GET_BE_U_2(p)
Definition: extract.h:875
#define GET_U_1(p)
Definition: extract.h:872
#define ND_TCHECK_4(p)
Definition: extract.h:561
#define ND_TCHECK_1(p)
Definition: extract.h:552
uint16_t in_cksum_shouldbe(uint16_t sum, uint16_t computed_sum)
Definition: in_cksum.c:157
uint16_t in_cksum(const struct cksum_vec *vec, int veclen)
Definition: in_cksum.c:57
#define IP_HL(ip)
Definition: ip.h:55
#define IPPROTO_TCP
Definition: ipproto.h:57
#define IPPROTO_UDP
Definition: ipproto.h:66
#define MPLS_TTL(x)
Definition: mpls.h:41
#define MPLS_EXP(x)
Definition: mpls.h:39
#define MPLS_STACK(x)
Definition: mpls.h:40
#define MPLS_LABEL(x)
Definition: mpls.h:38
unsigned char nd_uint16_t[2]
Definition: netdissect.h:47
#define ND_MIN(a, b)
Definition: netdissect.h:294
int print_unknown_data(netdissect_options *, const u_char *, const char *, u_int)
Definition: util-print.c:441
const char * tok2str(const struct tok *, const char *, u_int)
Definition: util-print.c:485
#define ND_TTEST_LEN(p, l)
Definition: netdissect.h:356
#define ND_TCHECK_SIZE(p)
Definition: netdissect.h:372
unsigned char nd_byte
Definition: netdissect.h:108
void nd_print_trunc(netdissect_options *)
Definition: util-print.c:409
void ip_print(netdissect_options *, const u_char *, u_int)
Definition: print-ip.c:319
unsigned char nd_ipv4[4]
Definition: netdissect.h:92
#define ND_PRINT(...)
Definition: netdissect.h:385
unsigned char nd_uint32_t[4]
Definition: netdissect.h:49
unsigned char nd_uint8_t[1]
Definition: netdissect.h:46
int snprintf(char *, size_t, const char *,...)
#define ICMP_UNREACH_NET_PROHIB
Definition: print-icmp.c:122
#define ICMP_UNREACH_HOST
Definition: print-icmp.c:114
#define ICMP_UNREACH_NET_UNKNOWN
Definition: print-icmp.c:119
const char * icmp_tstamp_print(u_int)
Definition: print-icmp.c:279
#define ICMP_UNREACH_NEEDFRAG
Definition: print-icmp.c:117
#define ICMP_ROUTERADVERT
Definition: print-icmp.c:133
#define ICMP_ROUTERSOLICIT
Definition: print-icmp.c:134
#define ICMP_IREQ
Definition: print-icmp.c:142
#define ICMP_UNREACH_ISOLATED
Definition: print-icmp.c:121
#define ICMP_REDIRECT
Definition: print-icmp.c:127
#define ICMP_UNREACH_TOSHOST
Definition: print-icmp.c:125
#define ICMP_UNREACH_HOST_PRECEDENCE
Definition: print-icmp.c:185
#define ICMP_MPLS_EXT_EXTRACT_VERSION(x)
Definition: print-icmp.c:89
#define ICMP_TSTAMP
Definition: print-icmp.c:140
#define ICMP_EXTD_MINLEN
Definition: print-icmp.c:101
#define ICMP_REDIRECT_HOST
Definition: print-icmp.c:129
#define ICMP_MPLS_EXT_TYPE(type)
Definition: print-icmp.c:153
#define ICMP_UNREACH_PROTOCOL
Definition: print-icmp.c:115
#define ICMP_UNREACH_SRCFAIL
Definition: print-icmp.c:118
void icmp_print(netdissect_options *ndo, const u_char *bp, u_int plen, const u_char *bp2, int fragmented)
Definition: print-icmp.c:294
static const struct tok icmp2str[]
Definition: print-icmp.c:192
#define ICMP_ECHOREPLY
Definition: print-icmp.c:111
#define ICMP_SOURCEQUENCH
Definition: print-icmp.c:126
#define ICMP_TIMXCEED_INTRANS
Definition: print-icmp.c:136
#define ICMP_TIMXCEED
Definition: print-icmp.c:135
#define ICMP_UNREACH_PRECEDENCE_CUTOFF
Definition: print-icmp.c:188
#define ICMP_REDIRECT_TOSHOST
Definition: print-icmp.c:131
#define ICMP_PARAMPROB
Definition: print-icmp.c:138
#define ICMP_ERRTYPE(type)
Definition: print-icmp.c:149
#define ICMP_IREQREPLY
Definition: print-icmp.c:143
#define ICMP_UNREACH_TOSNET
Definition: print-icmp.c:124
#define ICMP_UNREACH_HOST_UNKNOWN
Definition: print-icmp.c:120
static const struct tok icmp_mpls_ext_obj_values[]
Definition: print-icmp.c:268
#define ICMP_UNREACH_FILTER_PROHIB
Definition: print-icmp.c:182
#define ICMP_MASKREQ
Definition: print-icmp.c:144
#define ICMP_UNREACH
Definition: print-icmp.c:112
#define ICMP_ECHO
Definition: print-icmp.c:132
#define ICMP_UNREACH_NET
Definition: print-icmp.c:113
#define ICMP_REDIRECT_NET
Definition: print-icmp.c:128
#define ICMP_UNREACH_HOST_PROHIB
Definition: print-icmp.c:123
#define ICMP_TIMXCEED_REASS
Definition: print-icmp.c:137
#define ICMP_REDIRECT_TOSNET
Definition: print-icmp.c:130
#define ICMP_MASKREPLY
Definition: print-icmp.c:145
#define ICMP_MPLS_EXT_VERSION
Definition: print-icmp.c:90
#define ICMP_UNREACH_PORT
Definition: print-icmp.c:116
#define ICMP_TSTAMPREPLY
Definition: print-icmp.c:141
const uint8_t * ptr
Definition: netdissect.h:722
nd_uint8_t icmp_length
Definition: print-icmp.c:254
nd_byte icmp_reserved
Definition: print-icmp.c:253
nd_byte icmp_ext_legacy_header[128]
Definition: print-icmp.c:256
nd_uint8_t icmp_code
Definition: print-icmp.c:251
nd_byte icmp_ext_data[1]
Definition: print-icmp.c:259
nd_byte icmp_ext_version_res[2]
Definition: print-icmp.c:257
nd_uint16_t icmp_checksum
Definition: print-icmp.c:252
nd_uint8_t icmp_type
Definition: print-icmp.c:250
nd_uint16_t icmp_ext_checksum
Definition: print-icmp.c:258
nd_byte icmp_reserved2[2]
Definition: print-icmp.c:255
nd_uint8_t icmp_type
Definition: print-icmp.c:51
nd_uint32_t ih_void
Definition: print-icmp.c:61
nd_ipv4 ih_gwaddr
Definition: print-icmp.c:56
nd_uint16_t icmp_cksum
Definition: print-icmp.c:53
nd_uint32_t id_mask
Definition: print-icmp.c:78
struct icmp::@40::id_ip id_ip
struct icmp::@39::ih_idseq ih_idseq
nd_uint32_t its_rtime
Definition: print-icmp.c:71
nd_uint16_t icd_id
Definition: print-icmp.c:58
union icmp::@39 icmp_hun
nd_uint16_t icd_seq
Definition: print-icmp.c:59
nd_byte id_data[1]
Definition: print-icmp.c:79
nd_uint32_t its_otime
Definition: print-icmp.c:70
union icmp::@40 icmp_dun
nd_uint32_t its_ttime
Definition: print-icmp.c:72
nd_uint8_t icmp_code
Definition: print-icmp.c:52
nd_uint8_t ih_pptr
Definition: print-icmp.c:55
struct ip idi_ip
Definition: print-icmp.c:75
struct icmp::@40::id_ts id_ts
nd_uint32_t ird_addr
Definition: print-icmp.c:219
nd_uint32_t ird_pref
Definition: print-icmp.c:220
nd_uint8_t ird_addrsiz
Definition: print-icmp.c:214
nd_uint8_t ird_addrnum
Definition: print-icmp.c:213
nd_uint16_t ird_lifetime
Definition: print-icmp.c:215
Definition: ip.h:52
nd_uint16_t ip_len
Definition: ip.h:57
nd_uint16_t nexthopmtu
Definition: print-icmp.c:208
nd_uint16_t unused
Definition: print-icmp.c:207
const u_char * ndo_snapend
Definition: netdissect.h:239
const char * ndo_protocol
Definition: netdissect.h:218
Definition: udp.h:40
nd_uint16_t uh_dport
Definition: udp.h:42