Import tcpdump-3.9.7
[dragonfly.git] / contrib / tcpdump-3.9 / 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 #ifndef lint
23 static const char rcsid[] _U_ =
24     "@(#) $Header: /tcpdump/master/tcpdump/print-icmp.c,v 1.81.2.4 2006/12/12 14:33:20 hannes Exp $ (LBL)";
25 #endif
26
27 #ifdef HAVE_CONFIG_H
28 #include "config.h"
29 #endif
30
31 #include <tcpdump-stdinc.h>
32
33 #include <stdio.h>
34 #include <string.h>
35
36 #include "interface.h"
37 #include "addrtoname.h"
38 #include "extract.h"                    /* must come after interface.h */
39
40 #include "ip.h"
41 #include "udp.h"
42 #include "ipproto.h"
43 #include "mpls.h"
44
45 /*
46  * Interface Control Message Protocol Definitions.
47  * Per RFC 792, September 1981.
48  */
49
50 /*
51  * Structure of an icmp header.
52  */
53 struct icmp {
54         u_int8_t  icmp_type;            /* type of message, see below */
55         u_int8_t  icmp_code;            /* type sub code */
56         u_int16_t icmp_cksum;           /* ones complement cksum of struct */
57         union {
58                 u_int8_t ih_pptr;                       /* ICMP_PARAMPROB */
59                 struct in_addr ih_gwaddr;       /* ICMP_REDIRECT */
60                 struct ih_idseq {
61                         u_int16_t icd_id;
62                         u_int16_t icd_seq;
63                 } ih_idseq;
64                 u_int32_t ih_void;
65         } icmp_hun;
66 #define icmp_pptr       icmp_hun.ih_pptr
67 #define icmp_gwaddr     icmp_hun.ih_gwaddr
68 #define icmp_id         icmp_hun.ih_idseq.icd_id
69 #define icmp_seq        icmp_hun.ih_idseq.icd_seq
70 #define icmp_void       icmp_hun.ih_void
71         union {
72                 struct id_ts {
73                         u_int32_t its_otime;
74                         u_int32_t its_rtime;
75                         u_int32_t its_ttime;
76                 } id_ts;
77                 struct id_ip  {
78                         struct ip idi_ip;
79                         /* options and then 64 bits of data */
80                 } id_ip;
81                 u_int32_t id_mask;
82                 u_int8_t id_data[1];
83         } icmp_dun;
84 #define icmp_otime      icmp_dun.id_ts.its_otime
85 #define icmp_rtime      icmp_dun.id_ts.its_rtime
86 #define icmp_ttime      icmp_dun.id_ts.its_ttime
87 #define icmp_ip         icmp_dun.id_ip.idi_ip
88 #define icmp_mask       icmp_dun.id_mask
89 #define icmp_data       icmp_dun.id_data
90 };
91
92 #define ICMP_MPLS_EXT_EXTRACT_VERSION(x) (((x)&0xf0)>>4) 
93 #define ICMP_MPLS_EXT_VERSION 2
94
95 /*
96  * Lower bounds on packet lengths for various types.
97  * For the error advice packets must first insure that the
98  * packet is large enought to contain the returned ip header.
99  * Only then can we do the check to see if 64 bits of packet
100  * data have been returned, since we need to check the returned
101  * ip header length.
102  */
103 #define ICMP_MINLEN     8                               /* abs minimum */
104 #define ICMP_EXTD_MINLEN (156 - sizeof (struct ip))     /* draft-bonica-internet-icmp-08 */
105 #define ICMP_TSLEN      (8 + 3 * sizeof (u_int32_t))    /* timestamp */
106 #define ICMP_MASKLEN    12                              /* address mask */
107 #define ICMP_ADVLENMIN  (8 + sizeof (struct ip) + 8)    /* min */
108 #define ICMP_ADVLEN(p)  (8 + (IP_HL(&(p)->icmp_ip) << 2) + 8)
109         /* N.B.: must separately check that ip_hl >= 5 */
110
111 /*
112  * Definition of type and code field values.
113  */
114 #define ICMP_ECHOREPLY          0               /* echo reply */
115 #define ICMP_UNREACH            3               /* dest unreachable, codes: */
116 #define         ICMP_UNREACH_NET        0               /* bad net */
117 #define         ICMP_UNREACH_HOST       1               /* bad host */
118 #define         ICMP_UNREACH_PROTOCOL   2               /* bad protocol */
119 #define         ICMP_UNREACH_PORT       3               /* bad port */
120 #define         ICMP_UNREACH_NEEDFRAG   4               /* IP_DF caused drop */
121 #define         ICMP_UNREACH_SRCFAIL    5               /* src route failed */
122 #define         ICMP_UNREACH_NET_UNKNOWN 6              /* unknown net */
123 #define         ICMP_UNREACH_HOST_UNKNOWN 7             /* unknown host */
124 #define         ICMP_UNREACH_ISOLATED   8               /* src host isolated */
125 #define         ICMP_UNREACH_NET_PROHIB 9               /* prohibited access */
126 #define         ICMP_UNREACH_HOST_PROHIB 10             /* ditto */
127 #define         ICMP_UNREACH_TOSNET     11              /* bad tos for net */
128 #define         ICMP_UNREACH_TOSHOST    12              /* bad tos for host */
129 #define ICMP_SOURCEQUENCH       4               /* packet lost, slow down */
130 #define ICMP_REDIRECT           5               /* shorter route, codes: */
131 #define         ICMP_REDIRECT_NET       0               /* for network */
132 #define         ICMP_REDIRECT_HOST      1               /* for host */
133 #define         ICMP_REDIRECT_TOSNET    2               /* for tos and net */
134 #define         ICMP_REDIRECT_TOSHOST   3               /* for tos and host */
135 #define ICMP_ECHO               8               /* echo service */
136 #define ICMP_ROUTERADVERT       9               /* router advertisement */
137 #define ICMP_ROUTERSOLICIT      10              /* router solicitation */
138 #define ICMP_TIMXCEED           11              /* time exceeded, code: */
139 #define         ICMP_TIMXCEED_INTRANS   0               /* ttl==0 in transit */
140 #define         ICMP_TIMXCEED_REASS     1               /* ttl==0 in reass */
141 #define ICMP_PARAMPROB          12              /* ip header bad */
142 #define         ICMP_PARAMPROB_OPTABSENT 1              /* req. opt. absent */
143 #define ICMP_TSTAMP             13              /* timestamp request */
144 #define ICMP_TSTAMPREPLY        14              /* timestamp reply */
145 #define ICMP_IREQ               15              /* information request */
146 #define ICMP_IREQREPLY          16              /* information reply */
147 #define ICMP_MASKREQ            17              /* address mask request */
148 #define ICMP_MASKREPLY          18              /* address mask reply */
149
150 #define ICMP_MAXTYPE            18
151
152 #define ICMP_INFOTYPE(type) \
153         ((type) == ICMP_ECHOREPLY || (type) == ICMP_ECHO || \
154         (type) == ICMP_ROUTERADVERT || (type) == ICMP_ROUTERSOLICIT || \
155         (type) == ICMP_TSTAMP || (type) == ICMP_TSTAMPREPLY || \
156         (type) == ICMP_IREQ || (type) == ICMP_IREQREPLY || \
157         (type) == ICMP_MASKREQ || (type) == ICMP_MASKREPLY)
158 #define ICMP_MPLS_EXT_TYPE(type) \
159         ((type) == ICMP_UNREACH || \
160          (type) == ICMP_TIMXCEED || \
161          (type) == ICMP_PARAMPROB)
162 /* rfc1700 */
163 #ifndef ICMP_UNREACH_NET_UNKNOWN
164 #define ICMP_UNREACH_NET_UNKNOWN        6       /* destination net unknown */
165 #endif
166 #ifndef ICMP_UNREACH_HOST_UNKNOWN
167 #define ICMP_UNREACH_HOST_UNKNOWN       7       /* destination host unknown */
168 #endif
169 #ifndef ICMP_UNREACH_ISOLATED
170 #define ICMP_UNREACH_ISOLATED           8       /* source host isolated */
171 #endif
172 #ifndef ICMP_UNREACH_NET_PROHIB
173 #define ICMP_UNREACH_NET_PROHIB         9       /* admin prohibited net */
174 #endif
175 #ifndef ICMP_UNREACH_HOST_PROHIB
176 #define ICMP_UNREACH_HOST_PROHIB        10      /* admin prohibited host */
177 #endif
178 #ifndef ICMP_UNREACH_TOSNET
179 #define ICMP_UNREACH_TOSNET             11      /* tos prohibited net */
180 #endif
181 #ifndef ICMP_UNREACH_TOSHOST
182 #define ICMP_UNREACH_TOSHOST            12      /* tos prohibited host */
183 #endif
184
185 /* rfc1716 */
186 #ifndef ICMP_UNREACH_FILTER_PROHIB
187 #define ICMP_UNREACH_FILTER_PROHIB      13      /* admin prohibited filter */
188 #endif
189 #ifndef ICMP_UNREACH_HOST_PRECEDENCE
190 #define ICMP_UNREACH_HOST_PRECEDENCE    14      /* host precedence violation */
191 #endif
192 #ifndef ICMP_UNREACH_PRECEDENCE_CUTOFF
193 #define ICMP_UNREACH_PRECEDENCE_CUTOFF  15      /* precedence cutoff */
194 #endif
195
196 /* Most of the icmp types */
197 static struct tok icmp2str[] = {
198         { ICMP_ECHOREPLY,               "echo reply" },
199         { ICMP_SOURCEQUENCH,            "source quench" },
200         { ICMP_ECHO,                    "echo request" },
201         { ICMP_ROUTERSOLICIT,           "router solicitation" },
202         { ICMP_TSTAMP,                  "time stamp request" },
203         { ICMP_TSTAMPREPLY,             "time stamp reply" },
204         { ICMP_IREQ,                    "information request" },
205         { ICMP_IREQREPLY,               "information reply" },
206         { ICMP_MASKREQ,                 "address mask request" },
207         { 0,                            NULL }
208 };
209
210 /* Formats for most of the ICMP_UNREACH codes */
211 static struct tok unreach2str[] = {
212         { ICMP_UNREACH_NET,             "net %s unreachable" },
213         { ICMP_UNREACH_HOST,            "host %s unreachable" },
214         { ICMP_UNREACH_SRCFAIL,
215             "%s unreachable - source route failed" },
216         { ICMP_UNREACH_NET_UNKNOWN,     "net %s unreachable - unknown" },
217         { ICMP_UNREACH_HOST_UNKNOWN,    "host %s unreachable - unknown" },
218         { ICMP_UNREACH_ISOLATED,
219             "%s unreachable - source host isolated" },
220         { ICMP_UNREACH_NET_PROHIB,
221             "net %s unreachable - admin prohibited" },
222         { ICMP_UNREACH_HOST_PROHIB,
223             "host %s unreachable - admin prohibited" },
224         { ICMP_UNREACH_TOSNET,
225             "net %s unreachable - tos prohibited" },
226         { ICMP_UNREACH_TOSHOST,
227             "host %s unreachable - tos prohibited" },
228         { ICMP_UNREACH_FILTER_PROHIB,
229             "host %s unreachable - admin prohibited filter" },
230         { ICMP_UNREACH_HOST_PRECEDENCE,
231             "host %s unreachable - host precedence violation" },
232         { ICMP_UNREACH_PRECEDENCE_CUTOFF,
233             "host %s unreachable - precedence cutoff" },
234         { 0,                            NULL }
235 };
236
237 /* Formats for the ICMP_REDIRECT codes */
238 static struct tok type2str[] = {
239         { ICMP_REDIRECT_NET,            "redirect %s to net %s" },
240         { ICMP_REDIRECT_HOST,           "redirect %s to host %s" },
241         { ICMP_REDIRECT_TOSNET,         "redirect-tos %s to net %s" },
242         { ICMP_REDIRECT_TOSHOST,        "redirect-tos %s to host %s" },
243         { 0,                            NULL }
244 };
245
246 /* rfc1191 */
247 struct mtu_discovery {
248         u_int16_t unused;
249         u_int16_t nexthopmtu;
250 };
251
252 /* rfc1256 */
253 struct ih_rdiscovery {
254         u_int8_t ird_addrnum;
255         u_int8_t ird_addrsiz;
256         u_int16_t ird_lifetime;
257 };
258
259 struct id_rdiscovery {
260         u_int32_t ird_addr;
261         u_int32_t ird_pref;
262 };
263
264 /*
265  * draft-bonica-internet-icmp-08
266  *
267  * The Destination Unreachable, Time Exceeded
268  * and Parameter Problem messages are slighly changed as per
269  * the above draft. A new Length field gets added to give
270  * the caller an idea about the length of the piggypacked
271  * IP packet before the MPLS extension header starts.
272  *
273  * The Length field represents length of the padded "original datagram"
274  * field  measured in 32-bit words.
275  *
276  * 0                   1                   2                   3
277  * 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
278  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
279  * |     Type      |     Code      |          Checksum             |
280  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
281  * |     unused    |    Length     |          unused               |
282  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
283  * |      Internet Header + leading octets of original datagram    |
284  * |                                                               |
285  * |                           //                                  |
286  * |                                                               |
287  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
288  */
289
290 struct icmp_ext_t {
291     u_int8_t icmp_type;
292     u_int8_t icmp_code;
293     u_int8_t icmp_checksum[2];
294     u_int8_t icmp_reserved;
295     u_int8_t icmp_length;
296     u_int8_t icmp_reserved2[2];
297     u_int8_t icmp_ext_legacy_header[128]; /* extension header starts 128 bytes after ICMP header */
298     u_int8_t icmp_ext_version_res[2];
299     u_int8_t icmp_ext_checksum[2];
300     u_int8_t icmp_ext_data[1];
301 };
302
303 struct icmp_mpls_ext_common_header_t {
304 };
305
306 struct icmp_mpls_ext_object_header_t {
307     u_int8_t length[2];
308     u_int8_t class_num;
309     u_int8_t ctype;
310 };
311
312 static const struct tok icmp_mpls_ext_obj_values[] = {
313     { 1, "MPLS Stack Entry" },
314     { 2, "Extended Payload" },
315     { 0, NULL}
316 };
317
318 /* prototypes */
319 const char *icmp_tstamp_print(u_int);
320
321 /* print the milliseconds since midnight UTC */
322 const char *
323 icmp_tstamp_print(u_int tstamp) {
324     u_int msec,sec,min,hrs;
325
326     static char buf[64];
327
328     msec = tstamp % 1000;
329     sec = tstamp / 1000;
330     min = sec / 60; sec -= min * 60;
331     hrs = min / 60; min -= hrs * 60;
332     snprintf(buf, sizeof(buf), "%02u:%02u:%02u.%03u",hrs,min,sec,msec);
333     return buf;
334 }
335  
336 void
337 icmp_print(const u_char *bp, u_int plen, const u_char *bp2, int fragmented)
338 {
339         char *cp;
340         const struct icmp *dp;
341         const struct icmp_ext_t *ext_dp;
342         const struct ip *ip;
343         const char *str, *fmt;
344         const struct ip *oip;
345         const struct udphdr *ouh;
346         const u_int8_t *obj_tptr;
347         u_int32_t raw_label;
348         const u_char *snapend_save;
349         const struct icmp_mpls_ext_object_header_t *icmp_mpls_ext_object_header;
350         u_int hlen, dport, mtu, obj_tlen, obj_class_num, obj_ctype;
351         char buf[MAXHOSTNAMELEN + 100];
352
353         dp = (struct icmp *)bp;
354         ext_dp = (struct icmp_ext_t *)bp;
355         ip = (struct ip *)bp2;
356         str = buf;
357
358         TCHECK(dp->icmp_code);
359         switch (dp->icmp_type) {
360
361         case ICMP_ECHO:
362         case ICMP_ECHOREPLY:
363                 TCHECK(dp->icmp_seq);
364                 (void)snprintf(buf, sizeof(buf), "echo %s, id %u, seq %u",
365                                dp->icmp_type == ICMP_ECHO ?
366                                "request" : "reply",
367                                EXTRACT_16BITS(&dp->icmp_id),
368                                EXTRACT_16BITS(&dp->icmp_seq));
369                 break;
370
371         case ICMP_UNREACH:
372                 TCHECK(dp->icmp_ip.ip_dst);
373                 switch (dp->icmp_code) {
374
375                 case ICMP_UNREACH_PROTOCOL:
376                         TCHECK(dp->icmp_ip.ip_p);
377                         (void)snprintf(buf, sizeof(buf),
378                             "%s protocol %d unreachable",
379                             ipaddr_string(&dp->icmp_ip.ip_dst),
380                             dp->icmp_ip.ip_p);
381                         break;
382
383                 case ICMP_UNREACH_PORT:
384                         TCHECK(dp->icmp_ip.ip_p);
385                         oip = &dp->icmp_ip;
386                         hlen = IP_HL(oip) * 4;
387                         ouh = (struct udphdr *)(((u_char *)oip) + hlen);
388                         TCHECK(ouh->uh_dport);
389                         dport = EXTRACT_16BITS(&ouh->uh_dport);
390                         switch (oip->ip_p) {
391
392                         case IPPROTO_TCP:
393                                 (void)snprintf(buf, sizeof(buf),
394                                         "%s tcp port %s unreachable",
395                                         ipaddr_string(&oip->ip_dst),
396                                         tcpport_string(dport));
397                                 break;
398
399                         case IPPROTO_UDP:
400                                 (void)snprintf(buf, sizeof(buf),
401                                         "%s udp port %s unreachable",
402                                         ipaddr_string(&oip->ip_dst),
403                                         udpport_string(dport));
404                                 break;
405
406                         default:
407                                 (void)snprintf(buf, sizeof(buf),
408                                         "%s protocol %d port %d unreachable",
409                                         ipaddr_string(&oip->ip_dst),
410                                         oip->ip_p, dport);
411                                 break;
412                         }
413                         break;
414
415                 case ICMP_UNREACH_NEEDFRAG:
416                     {
417                         register const struct mtu_discovery *mp;
418                         mp = (struct mtu_discovery *)&dp->icmp_void;
419                         mtu = EXTRACT_16BITS(&mp->nexthopmtu);
420                         if (mtu) {
421                                 (void)snprintf(buf, sizeof(buf),
422                                     "%s unreachable - need to frag (mtu %d)",
423                                     ipaddr_string(&dp->icmp_ip.ip_dst), mtu);
424                         } else {
425                                 (void)snprintf(buf, sizeof(buf),
426                                     "%s unreachable - need to frag",
427                                     ipaddr_string(&dp->icmp_ip.ip_dst));
428                         }
429                     }
430                         break;
431
432                 default:
433                         fmt = tok2str(unreach2str, "#%d %%s unreachable",
434                             dp->icmp_code);
435                         (void)snprintf(buf, sizeof(buf), fmt,
436                             ipaddr_string(&dp->icmp_ip.ip_dst));
437                         break;
438                 }
439                 break;
440
441         case ICMP_REDIRECT:
442                 TCHECK(dp->icmp_ip.ip_dst);
443                 fmt = tok2str(type2str, "redirect-#%d %%s to net %%s",
444                     dp->icmp_code);
445                 (void)snprintf(buf, sizeof(buf), fmt,
446                     ipaddr_string(&dp->icmp_ip.ip_dst),
447                     ipaddr_string(&dp->icmp_gwaddr));
448                 break;
449
450         case ICMP_ROUTERADVERT:
451             {
452                 register const struct ih_rdiscovery *ihp;
453                 register const struct id_rdiscovery *idp;
454                 u_int lifetime, num, size;
455
456                 (void)snprintf(buf, sizeof(buf), "router advertisement");
457                 cp = buf + strlen(buf);
458
459                 ihp = (struct ih_rdiscovery *)&dp->icmp_void;
460                 TCHECK(*ihp);
461                 (void)strncpy(cp, " lifetime ", sizeof(buf) - (cp - buf));
462                 cp = buf + strlen(buf);
463                 lifetime = EXTRACT_16BITS(&ihp->ird_lifetime);
464                 if (lifetime < 60) {
465                         (void)snprintf(cp, sizeof(buf) - (cp - buf), "%u",
466                             lifetime);
467                 } else if (lifetime < 60 * 60) {
468                         (void)snprintf(cp, sizeof(buf) - (cp - buf), "%u:%02u",
469                             lifetime / 60, lifetime % 60);
470                 } else {
471                         (void)snprintf(cp, sizeof(buf) - (cp - buf),
472                             "%u:%02u:%02u",
473                             lifetime / 3600,
474                             (lifetime % 3600) / 60,
475                             lifetime % 60);
476                 }
477                 cp = buf + strlen(buf);
478
479                 num = ihp->ird_addrnum;
480                 (void)snprintf(cp, sizeof(buf) - (cp - buf), " %d:", num);
481                 cp = buf + strlen(buf);
482
483                 size = ihp->ird_addrsiz;
484                 if (size != 2) {
485                         (void)snprintf(cp, sizeof(buf) - (cp - buf),
486                             " [size %d]", size);
487                         break;
488                 }
489                 idp = (struct id_rdiscovery *)&dp->icmp_data;
490                 while (num-- > 0) {
491                         TCHECK(*idp);
492                         (void)snprintf(cp, sizeof(buf) - (cp - buf), " {%s %u}",
493                             ipaddr_string(&idp->ird_addr),
494                             EXTRACT_32BITS(&idp->ird_pref));
495                         cp = buf + strlen(buf);
496                         ++idp;
497                 }
498             }
499                 break;
500
501         case ICMP_TIMXCEED:
502                 TCHECK(dp->icmp_ip.ip_dst);
503                 switch (dp->icmp_code) {
504
505                 case ICMP_TIMXCEED_INTRANS:
506                         str = "time exceeded in-transit";
507                         break;
508
509                 case ICMP_TIMXCEED_REASS:
510                         str = "ip reassembly time exceeded";
511                         break;
512
513                 default:
514                         (void)snprintf(buf, sizeof(buf), "time exceeded-#%d",
515                             dp->icmp_code);
516                         break;
517                 }
518                 break;
519
520         case ICMP_PARAMPROB:
521                 if (dp->icmp_code)
522                         (void)snprintf(buf, sizeof(buf),
523                             "parameter problem - code %d", dp->icmp_code);
524                 else {
525                         TCHECK(dp->icmp_pptr);
526                         (void)snprintf(buf, sizeof(buf),
527                             "parameter problem - octet %d", dp->icmp_pptr);
528                 }
529                 break;
530
531         case ICMP_MASKREPLY:
532                 TCHECK(dp->icmp_mask);
533                 (void)snprintf(buf, sizeof(buf), "address mask is 0x%08x",
534                     EXTRACT_32BITS(&dp->icmp_mask));
535                 break;
536
537         case ICMP_TSTAMP:
538                 TCHECK(dp->icmp_seq);
539                 (void)snprintf(buf, sizeof(buf),
540                     "time stamp query id %u seq %u",
541                     EXTRACT_16BITS(&dp->icmp_id),
542                     EXTRACT_16BITS(&dp->icmp_seq));
543                 break;
544
545         case ICMP_TSTAMPREPLY:
546                 TCHECK(dp->icmp_ttime);
547                 (void)snprintf(buf, sizeof(buf),
548                     "time stamp reply id %u seq %u: org %s",
549                                EXTRACT_16BITS(&dp->icmp_id),
550                                EXTRACT_16BITS(&dp->icmp_seq),
551                                icmp_tstamp_print(EXTRACT_32BITS(&dp->icmp_otime)));
552
553                 (void)snprintf(buf+strlen(buf),sizeof(buf)-strlen(buf),", recv %s",
554                          icmp_tstamp_print(EXTRACT_32BITS(&dp->icmp_rtime)));
555                 (void)snprintf(buf+strlen(buf),sizeof(buf)-strlen(buf),", xmit %s",
556                          icmp_tstamp_print(EXTRACT_32BITS(&dp->icmp_ttime)));
557                 break;
558
559         default:
560                 str = tok2str(icmp2str, "type-#%d", dp->icmp_type);
561                 break;
562         }
563         (void)printf("ICMP %s, length %u", str, plen);
564         if (vflag && !fragmented) { /* don't attempt checksumming if this is a frag */
565                 u_int16_t sum, icmp_sum;
566                 if (TTEST2(*bp, plen)) {
567                         sum = in_cksum((u_short*)dp, plen, 0);
568                         if (sum != 0) {
569                                 icmp_sum = EXTRACT_16BITS(&dp->icmp_cksum);
570                                 (void)printf(" (wrong icmp cksum %x (->%x)!)",
571                                              icmp_sum,
572                                              in_cksum_shouldbe(icmp_sum, sum));
573                         }
574                 }
575         }
576
577         /*
578          * print the remnants of the IP packet.
579          * save the snaplength as this may get overidden in the IP printer.
580          */
581         if (vflag >= 1 && !ICMP_INFOTYPE(dp->icmp_type)) {
582                 bp += 8;
583                 (void)printf("\n\t");
584                 ip = (struct ip *)bp;
585                 snaplen = snapend - bp;
586                 snapend_save = snapend;
587                 ip_print(gndo, bp, EXTRACT_16BITS(&ip->ip_len));
588                 snapend = snapend_save;
589         }
590
591         /*
592          * Attempt to decode the MPLS extensions only for some ICMP types.
593          */
594         if (vflag >= 1 && plen > ICMP_EXTD_MINLEN && ICMP_MPLS_EXT_TYPE(dp->icmp_type)) {
595
596             TCHECK(*ext_dp);
597
598             /*
599              * Check first if the mpls extension header shows a non-zero length.
600              * If the length field is not set then silently verify the checksum
601              * to check if an extension header is present. This is expedient,
602              * however not all implementations set the length field proper.
603              */
604             if (!ext_dp->icmp_length &&
605                 in_cksum((const u_short *)&ext_dp->icmp_ext_version_res,
606                          plen - ICMP_EXTD_MINLEN, 0)) {
607                 return;
608             }
609
610             printf("\n\tMPLS extension v%u",
611                    ICMP_MPLS_EXT_EXTRACT_VERSION(*(ext_dp->icmp_ext_version_res)));
612             
613             /*
614              * Sanity checking of the header.
615              */
616             if (ICMP_MPLS_EXT_EXTRACT_VERSION(*(ext_dp->icmp_ext_version_res)) !=
617                 ICMP_MPLS_EXT_VERSION) {
618                 printf(" packet not supported");
619                 return;
620             }
621
622             hlen = plen - ICMP_EXTD_MINLEN;
623             printf(", checksum 0x%04x (%scorrect), length %u",
624                    EXTRACT_16BITS(ext_dp->icmp_ext_checksum),
625                    in_cksum((const u_short *)&ext_dp->icmp_ext_version_res,
626                             plen - ICMP_EXTD_MINLEN, 0) ? "in" : "",
627                    hlen);
628
629             hlen -= 4; /* subtract common header size */
630             obj_tptr = (u_int8_t *)ext_dp->icmp_ext_data;
631
632             while (hlen > sizeof(struct icmp_mpls_ext_object_header_t)) {
633
634                 icmp_mpls_ext_object_header = (struct icmp_mpls_ext_object_header_t *)obj_tptr;
635                 TCHECK(*icmp_mpls_ext_object_header);
636                 obj_tlen = EXTRACT_16BITS(icmp_mpls_ext_object_header->length);
637                 obj_class_num = icmp_mpls_ext_object_header->class_num;
638                 obj_ctype = icmp_mpls_ext_object_header->ctype;
639                 obj_tptr += sizeof(struct icmp_mpls_ext_object_header_t);
640
641                 printf("\n\t  %s Object (%u), Class-Type: %u, length %u",
642                        tok2str(icmp_mpls_ext_obj_values,"unknown",obj_class_num),
643                        obj_class_num,
644                        obj_ctype,
645                        obj_tlen);
646
647                 hlen-=sizeof(struct icmp_mpls_ext_object_header_t); /* length field includes tlv header */
648
649                 /* infinite loop protection */                
650                 if ((obj_class_num == 0) ||
651                     (obj_tlen < sizeof(struct icmp_mpls_ext_object_header_t))) {
652                     return;
653                 }
654                 obj_tlen-=sizeof(struct icmp_mpls_ext_object_header_t);
655
656                 switch (obj_class_num) {
657                 case 1:
658                     switch(obj_ctype) {
659                     case 1:
660                         TCHECK2(*obj_tptr, 4);
661                         raw_label = EXTRACT_32BITS(obj_tptr);
662                         printf("\n\t    label %u, exp %u", MPLS_LABEL(raw_label), MPLS_EXP(raw_label));
663                         if (MPLS_STACK(raw_label))
664                             printf(", [S]");
665                         printf(", ttl %u", MPLS_TTL(raw_label));
666                         break;
667                     default:
668                         print_unknown_data(obj_tptr, "\n\t    ", obj_tlen);
669                     }
670                     break;
671
672                /*
673                 *  FIXME those are the defined objects that lack a decoder
674                 *  you are welcome to contribute code ;-)
675                 */
676                 case 2:
677                 default:
678                     print_unknown_data(obj_tptr, "\n\t    ", obj_tlen);
679                     break;
680                 }
681                 if (hlen < obj_tlen)
682                     break;
683                 hlen -= obj_tlen;
684                 obj_tptr += obj_tlen;
685             }
686         }
687
688         return;
689 trunc:
690         fputs("[|icmp]", stdout);
691 }