contrib/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  * $FreeBSD$
  22  */
  23
  24 #ifndef lint
  25 static const char rcsid[] _U_ =
  26     "@(#) $Header: /tcpdump/master/tcpdump/print-icmp.c,v 1.87 2007-09-13 17:42:31 guy Exp $ (LBL)";
  27 #endif
  28
  29 #ifdef HAVE_CONFIG_H
  30 #include "config.h"
  31 #endif
  32
  33 #include <tcpdump-stdinc.h>
  34
  35 #include <stdio.h>
  36 #include <string.h>
  37
  38 #include "interface.h"
  39 #include "addrtoname.h"
  40 #include "extract.h"                    /* must come after interface.h */
  41
  42 #include "ip.h"
  43 #include "udp.h"
  44 #include "ipproto.h"
  45 #include "mpls.h"
  46
  47 /*
  48  * Interface Control Message Protocol Definitions.
  49  * Per RFC 792, September 1981.
  50  */
  51
  52 /*
  53  * Structure of an icmp header.
  54  */
  55 struct icmp {
  56         u_int8_t  icmp_type;            /* type of message, see below */
  57         u_int8_t  icmp_code;            /* type sub code */
  58         u_int16_t icmp_cksum;           /* ones complement cksum of struct */
  59         union {
  60                 u_int8_t ih_pptr;                       /* ICMP_PARAMPROB */
  61                 struct in_addr ih_gwaddr;       /* ICMP_REDIRECT */
  62                 struct ih_idseq {
  63                         u_int16_t icd_id;
  64                         u_int16_t icd_seq;
  65                 } ih_idseq;
  66                 u_int32_t ih_void;
  67         } icmp_hun;
  68 #define icmp_pptr       icmp_hun.ih_pptr
  69 #define icmp_gwaddr     icmp_hun.ih_gwaddr
  70 #define icmp_id         icmp_hun.ih_idseq.icd_id
  71 #define icmp_seq        icmp_hun.ih_idseq.icd_seq
  72 #define icmp_void       icmp_hun.ih_void
  73         union {
  74                 struct id_ts {
  75                         u_int32_t its_otime;
  76                         u_int32_t its_rtime;
  77                         u_int32_t its_ttime;
  78                 } id_ts;
  79                 struct id_ip  {
  80                         struct ip idi_ip;
  81                         /* options and then 64 bits of data */
  82                 } id_ip;
  83                 u_int32_t id_mask;
  84                 u_int8_t id_data[1];
  85         } icmp_dun;
  86 #define icmp_otime      icmp_dun.id_ts.its_otime
  87 #define icmp_rtime      icmp_dun.id_ts.its_rtime
  88 #define icmp_ttime      icmp_dun.id_ts.its_ttime
  89 #define icmp_ip         icmp_dun.id_ip.idi_ip
  90 #define icmp_mask       icmp_dun.id_mask
  91 #define icmp_data       icmp_dun.id_data
  92 };
  93
  94 #define ICMP_MPLS_EXT_EXTRACT_VERSION(x) (((x)&0xf0)>>4)
  95 #define ICMP_MPLS_EXT_VERSION 2
  96
  97 /*
  98  * Lower bounds on packet lengths for various types.
  99  * For the error advice packets must first insure that the
 100  * packet is large enought to contain the returned ip header.
 101  * Only then can we do the check to see if 64 bits of packet
 102  * data have been returned, since we need to check the returned
 103  * ip header length.
 104  */
 105 #define ICMP_MINLEN     8                               /* abs minimum */
 106 #define ICMP_EXTD_MINLEN (156 - sizeof (struct ip))     /* draft-bonica-internet-icmp-08 */
 107 #define ICMP_TSLEN      (8 + 3 * sizeof (u_int32_t))    /* timestamp */
 108 #define ICMP_MASKLEN    12                              /* address mask */
 109 #define ICMP_ADVLENMIN  (8 + sizeof (struct ip) + 8)    /* min */
 110 #define ICMP_ADVLEN(p)  (8 + (IP_HL(&(p)->icmp_ip) << 2) + 8)
 111         /* N.B.: must separately check that ip_hl >= 5 */
 112
 113 /*
 114  * Definition of type and code field values.
 115  */
 116 #define ICMP_ECHOREPLY          0               /* echo reply */
 117 #define ICMP_UNREACH            3               /* dest unreachable, codes: */
 118 #define         ICMP_UNREACH_NET        0               /* bad net */
 119 #define         ICMP_UNREACH_HOST       1               /* bad host */
 120 #define         ICMP_UNREACH_PROTOCOL   2               /* bad protocol */
 121 #define         ICMP_UNREACH_PORT       3               /* bad port */
 122 #define         ICMP_UNREACH_NEEDFRAG   4               /* IP_DF caused drop */
 123 #define         ICMP_UNREACH_SRCFAIL    5               /* src route failed */
 124 #define         ICMP_UNREACH_NET_UNKNOWN 6              /* unknown net */
 125 #define         ICMP_UNREACH_HOST_UNKNOWN 7             /* unknown host */
 126 #define         ICMP_UNREACH_ISOLATED   8               /* src host isolated */
 127 #define         ICMP_UNREACH_NET_PROHIB 9               /* prohibited access */
 128 #define         ICMP_UNREACH_HOST_PROHIB 10             /* ditto */
 129 #define         ICMP_UNREACH_TOSNET     11              /* bad tos for net */
 130 #define         ICMP_UNREACH_TOSHOST    12              /* bad tos for host */
 131 #define ICMP_SOURCEQUENCH       4               /* packet lost, slow down */
 132 #define ICMP_REDIRECT           5               /* shorter route, codes: */
 133 #define         ICMP_REDIRECT_NET       0               /* for network */
 134 #define         ICMP_REDIRECT_HOST      1               /* for host */
 135 #define         ICMP_REDIRECT_TOSNET    2               /* for tos and net */
 136 #define         ICMP_REDIRECT_TOSHOST   3               /* for tos and host */
 137 #define ICMP_ECHO               8               /* echo service */
 138 #define ICMP_ROUTERADVERT       9               /* router advertisement */
 139 #define ICMP_ROUTERSOLICIT      10              /* router solicitation */
 140 #define ICMP_TIMXCEED           11              /* time exceeded, code: */
 141 #define         ICMP_TIMXCEED_INTRANS   0               /* ttl==0 in transit */
 142 #define         ICMP_TIMXCEED_REASS     1               /* ttl==0 in reass */
 143 #define ICMP_PARAMPROB          12              /* ip header bad */
 144 #define         ICMP_PARAMPROB_OPTABSENT 1              /* req. opt. absent */
 145 #define ICMP_TSTAMP             13              /* timestamp request */
 146 #define ICMP_TSTAMPREPLY        14              /* timestamp reply */
 147 #define ICMP_IREQ               15              /* information request */
 148 #define ICMP_IREQREPLY          16              /* information reply */
 149 #define ICMP_MASKREQ            17              /* address mask request */
 150 #define ICMP_MASKREPLY          18              /* address mask reply */
 151
 152 #define ICMP_MAXTYPE            18
 153
 154 #define ICMP_INFOTYPE(type) \
 155         ((type) == ICMP_ECHOREPLY || (type) == ICMP_ECHO || \
 156         (type) == ICMP_ROUTERADVERT || (type) == ICMP_ROUTERSOLICIT || \
 157         (type) == ICMP_TSTAMP || (type) == ICMP_TSTAMPREPLY || \
 158         (type) == ICMP_IREQ || (type) == ICMP_IREQREPLY || \
 159         (type) == ICMP_MASKREQ || (type) == ICMP_MASKREPLY)
 160 #define ICMP_MPLS_EXT_TYPE(type) \
 161         ((type) == ICMP_UNREACH || \
 162          (type) == ICMP_TIMXCEED || \
 163          (type) == ICMP_PARAMPROB)
 164 /* rfc1700 */
 165 #ifndef ICMP_UNREACH_NET_UNKNOWN
 166 #define ICMP_UNREACH_NET_UNKNOWN        6       /* destination net unknown */
 167 #endif
 168 #ifndef ICMP_UNREACH_HOST_UNKNOWN
 169 #define ICMP_UNREACH_HOST_UNKNOWN       7       /* destination host unknown */
 170 #endif
 171 #ifndef ICMP_UNREACH_ISOLATED
 172 #define ICMP_UNREACH_ISOLATED           8       /* source host isolated */
 173 #endif
 174 #ifndef ICMP_UNREACH_NET_PROHIB
 175 #define ICMP_UNREACH_NET_PROHIB         9       /* admin prohibited net */
 176 #endif
 177 #ifndef ICMP_UNREACH_HOST_PROHIB
 178 #define ICMP_UNREACH_HOST_PROHIB        10      /* admin prohibited host */
 179 #endif
 180 #ifndef ICMP_UNREACH_TOSNET
 181 #define ICMP_UNREACH_TOSNET             11      /* tos prohibited net */
 182 #endif
 183 #ifndef ICMP_UNREACH_TOSHOST
 184 #define ICMP_UNREACH_TOSHOST            12      /* tos prohibited host */
 185 #endif
 186
 187 /* rfc1716 */
 188 #ifndef ICMP_UNREACH_FILTER_PROHIB
 189 #define ICMP_UNREACH_FILTER_PROHIB      13      /* admin prohibited filter */
 190 #endif
 191 #ifndef ICMP_UNREACH_HOST_PRECEDENCE
 192 #define ICMP_UNREACH_HOST_PRECEDENCE    14      /* host precedence violation */
 193 #endif
 194 #ifndef ICMP_UNREACH_PRECEDENCE_CUTOFF
 195 #define ICMP_UNREACH_PRECEDENCE_CUTOFF  15      /* precedence cutoff */
 196 #endif
 197
 198 /* Most of the icmp types */
 199 static struct tok icmp2str[] = {
 200         { ICMP_ECHOREPLY,               "echo reply" },
 201         { ICMP_SOURCEQUENCH,            "source quench" },
 202         { ICMP_ECHO,                    "echo request" },
 203         { ICMP_ROUTERSOLICIT,           "router solicitation" },
 204         { ICMP_TSTAMP,                  "time stamp request" },
 205         { ICMP_TSTAMPREPLY,             "time stamp reply" },
 206         { ICMP_IREQ,                    "information request" },
 207         { ICMP_IREQREPLY,               "information reply" },
 208         { ICMP_MASKREQ,                 "address mask request" },
 209         { 0,                            NULL }
 210 };
 211
 212 /* Formats for most of the ICMP_UNREACH codes */
 213 static struct tok unreach2str[] = {
 214         { ICMP_UNREACH_NET,             "net %s unreachable" },
 215         { ICMP_UNREACH_HOST,            "host %s unreachable" },
 216         { ICMP_UNREACH_SRCFAIL,
 217             "%s unreachable - source route failed" },
 218         { ICMP_UNREACH_NET_UNKNOWN,     "net %s unreachable - unknown" },
 219         { ICMP_UNREACH_HOST_UNKNOWN,    "host %s unreachable - unknown" },
 220         { ICMP_UNREACH_ISOLATED,
 221             "%s unreachable - source host isolated" },
 222         { ICMP_UNREACH_NET_PROHIB,
 223             "net %s unreachable - admin prohibited" },
 224         { ICMP_UNREACH_HOST_PROHIB,
 225             "host %s unreachable - admin prohibited" },
 226         { ICMP_UNREACH_TOSNET,
 227             "net %s unreachable - tos prohibited" },
 228         { ICMP_UNREACH_TOSHOST,
 229             "host %s unreachable - tos prohibited" },
 230         { ICMP_UNREACH_FILTER_PROHIB,
 231             "host %s unreachable - admin prohibited filter" },
 232         { ICMP_UNREACH_HOST_PRECEDENCE,
 233             "host %s unreachable - host precedence violation" },
 234         { ICMP_UNREACH_PRECEDENCE_CUTOFF,
 235             "host %s unreachable - precedence cutoff" },
 236         { 0,                            NULL }
 237 };
 238
 239 /* Formats for the ICMP_REDIRECT codes */
 240 static struct tok type2str[] = {
 241         { ICMP_REDIRECT_NET,            "redirect %s to net %s" },
 242         { ICMP_REDIRECT_HOST,           "redirect %s to host %s" },
 243         { ICMP_REDIRECT_TOSNET,         "redirect-tos %s to net %s" },
 244         { ICMP_REDIRECT_TOSHOST,        "redirect-tos %s to host %s" },
 245         { 0,                            NULL }
 246 };
 247
 248 /* rfc1191 */
 249 struct mtu_discovery {
 250         u_int16_t unused;
 251         u_int16_t nexthopmtu;
 252 };
 253
 254 /* rfc1256 */
 255 struct ih_rdiscovery {
 256         u_int8_t ird_addrnum;
 257         u_int8_t ird_addrsiz;
 258         u_int16_t ird_lifetime;
 259 };
 260
 261 struct id_rdiscovery {
 262         u_int32_t ird_addr;
 263         u_int32_t ird_pref;
 264 };
 265
 266 /*
 267  * draft-bonica-internet-icmp-08
 268  *
 269  * The Destination Unreachable, Time Exceeded
 270  * and Parameter Problem messages are slighly changed as per
 271  * the above draft. A new Length field gets added to give
 272  * the caller an idea about the length of the piggypacked
 273  * IP packet before the MPLS extension header starts.
 274  *
 275  * The Length field represents length of the padded "original datagram"
 276  * field  measured in 32-bit words.
 277  *
 278  * 0                   1                   2                   3
 279  * 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
 280  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 281  * |     Type      |     Code      |          Checksum             |
 282  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 283  * |     unused    |    Length     |          unused               |
 284  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 285  * |      Internet Header + leading octets of original datagram    |
 286  * |                                                               |
 287  * |                           //                                  |
 288  * |                                                               |
 289  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 290  */
 291
 292 struct icmp_ext_t {
 293     u_int8_t icmp_type;
 294     u_int8_t icmp_code;
 295     u_int8_t icmp_checksum[2];
 296     u_int8_t icmp_reserved;
 297     u_int8_t icmp_length;
 298     u_int8_t icmp_reserved2[2];
 299     u_int8_t icmp_ext_legacy_header[128]; /* extension header starts 128 bytes after ICMP header */
 300     u_int8_t icmp_ext_version_res[2];
 301     u_int8_t icmp_ext_checksum[2];
 302     u_int8_t icmp_ext_data[1];
 303 };
 304
 305 struct icmp_mpls_ext_object_header_t {
 306     u_int8_t length[2];
 307     u_int8_t class_num;
 308     u_int8_t ctype;
 309 };
 310
 311 static const struct tok icmp_mpls_ext_obj_values[] = {
 312     { 1, "MPLS Stack Entry" },
 313     { 2, "Extended Payload" },
 314     { 0, NULL}
 315 };
 316
 317 /* prototypes */
 318 const char *icmp_tstamp_print(u_int);
 319
 320 /* print the milliseconds since midnight UTC */
 321 const char *
 322 icmp_tstamp_print(u_int tstamp) {
 323     u_int msec,sec,min,hrs;
 324
 325     static char buf[64];
 326
 327     msec = tstamp % 1000;
 328     sec = tstamp / 1000;
 329     min = sec / 60; sec -= min * 60;
 330     hrs = min / 60; min -= hrs * 60;
 331     snprintf(buf, sizeof(buf), "%02u:%02u:%02u.%03u",hrs,min,sec,msec);
 332     return buf;
 333 }
 334
 335 void
 336 icmp_print(const u_char *bp, u_int plen, const u_char *bp2, int fragmented)
 337 {
 338         char *cp;
 339         const struct icmp *dp;
 340         const struct icmp_ext_t *ext_dp;
 341         const struct ip *ip;
 342         const char *str, *fmt;
 343         const struct ip *oip;
 344         const struct udphdr *ouh;
 345         const u_int8_t *obj_tptr;
 346         u_int32_t raw_label;
 347         const u_char *snapend_save;
 348         const struct icmp_mpls_ext_object_header_t *icmp_mpls_ext_object_header;
 349         u_int hlen, dport, mtu, obj_tlen, obj_class_num, obj_ctype;
 350         char buf[MAXHOSTNAMELEN + 100];
 351         struct cksum_vec vec[1];
 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 *)(u_char *)&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                 struct cksum_vec vec[1];
 567                 if (TTEST2(*bp, plen)) {
 568                         vec[0].ptr = (const u_int8_t *)(void *)dp;
 569                         vec[0].len = plen;
 570                         sum = in_cksum(vec, 1);
 571                         if (sum != 0) {
 572                                 icmp_sum = EXTRACT_16BITS(&dp->icmp_cksum);
 573                                 (void)printf(" (wrong icmp cksum %x (->%x)!)",
 574                                              icmp_sum,
 575                                              in_cksum_shouldbe(icmp_sum, sum));
 576                         }
 577                 }
 578         }
 579
 580         /*
 581          * print the remnants of the IP packet.
 582          * save the snaplength as this may get overidden in the IP printer.
 583          */
 584         if (vflag >= 1 && !ICMP_INFOTYPE(dp->icmp_type)) {
 585                 bp += 8;
 586                 (void)printf("\n\t");
 587                 ip = (struct ip *)bp;
 588                 snaplen = snapend - bp;
 589                 snapend_save = snapend;
 590                 ip_print(gndo, bp, EXTRACT_16BITS(&ip->ip_len));
 591                 snapend = snapend_save;
 592         }
 593
 594         /*
 595          * Attempt to decode the MPLS extensions only for some ICMP types.
 596          */
 597         if (vflag >= 1 && plen > ICMP_EXTD_MINLEN && ICMP_MPLS_EXT_TYPE(dp->icmp_type)) {
 598
 599             TCHECK(*ext_dp);
 600
 601             /*
 602              * Check first if the mpls extension header shows a non-zero length.
 603              * If the length field is not set then silently verify the checksum
 604              * to check if an extension header is present. This is expedient,
 605              * however not all implementations set the length field proper.
 606              */
 607             if (!ext_dp->icmp_length) {
 608                 vec[0].ptr = (const u_int8_t *)(void *)&ext_dp->icmp_ext_version_res;
 609                 vec[0].len = plen - ICMP_EXTD_MINLEN;
 610                 if (in_cksum(vec, 1)) {
 611                     return;
 612                 }
 613             }
 614
 615             printf("\n\tMPLS extension v%u",
 616                    ICMP_MPLS_EXT_EXTRACT_VERSION(*(ext_dp->icmp_ext_version_res)));
 617
 618             /*
 619              * Sanity checking of the header.
 620              */
 621             if (ICMP_MPLS_EXT_EXTRACT_VERSION(*(ext_dp->icmp_ext_version_res)) !=
 622                 ICMP_MPLS_EXT_VERSION) {
 623                 printf(" packet not supported");
 624                 return;
 625             }
 626
 627             hlen = plen - ICMP_EXTD_MINLEN;
 628             vec[0].ptr = (const u_int8_t *)(void *)&ext_dp->icmp_ext_version_res;
 629             vec[0].len = hlen;
 630             printf(", checksum 0x%04x (%scorrect), length %u",
 631                    EXTRACT_16BITS(ext_dp->icmp_ext_checksum),
 632                    in_cksum(vec, 1) ? "in" : "",
 633                    hlen);
 634
 635             hlen -= 4; /* subtract common header size */
 636             obj_tptr = (u_int8_t *)ext_dp->icmp_ext_data;
 637
 638             while (hlen > sizeof(struct icmp_mpls_ext_object_header_t)) {
 639
 640                 icmp_mpls_ext_object_header = (struct icmp_mpls_ext_object_header_t *)obj_tptr;
 641                 TCHECK(*icmp_mpls_ext_object_header);
 642                 obj_tlen = EXTRACT_16BITS(icmp_mpls_ext_object_header->length);
 643                 obj_class_num = icmp_mpls_ext_object_header->class_num;
 644                 obj_ctype = icmp_mpls_ext_object_header->ctype;
 645                 obj_tptr += sizeof(struct icmp_mpls_ext_object_header_t);
 646
 647                 printf("\n\t  %s Object (%u), Class-Type: %u, length %u",
 648                        tok2str(icmp_mpls_ext_obj_values,"unknown",obj_class_num),
 649                        obj_class_num,
 650                        obj_ctype,
 651                        obj_tlen);
 652
 653                 hlen-=sizeof(struct icmp_mpls_ext_object_header_t); /* length field includes tlv header */
 654
 655                 /* infinite loop protection */
 656                 if ((obj_class_num == 0) ||
 657                     (obj_tlen < sizeof(struct icmp_mpls_ext_object_header_t))) {
 658                     return;
 659                 }
 660                 obj_tlen-=sizeof(struct icmp_mpls_ext_object_header_t);
 661
 662                 switch (obj_class_num) {
 663                 case 1:
 664                     switch(obj_ctype) {
 665                     case 1:
 666                         TCHECK2(*obj_tptr, 4);
 667                         raw_label = EXTRACT_32BITS(obj_tptr);
 668                         printf("\n\t    label %u, exp %u", MPLS_LABEL(raw_label), MPLS_EXP(raw_label));
 669                         if (MPLS_STACK(raw_label))
 670                             printf(", [S]");
 671                         printf(", ttl %u", MPLS_TTL(raw_label));
 672                         break;
 673                     default:
 674                         print_unknown_data(obj_tptr, "\n\t    ", obj_tlen);
 675                     }
 676                     break;
 677
 678                /*
 679                 *  FIXME those are the defined objects that lack a decoder
 680                 *  you are welcome to contribute code ;-)
 681                 */
 682                 case 2:
 683                 default:
 684                     print_unknown_data(obj_tptr, "\n\t    ", obj_tlen);
 685                     break;
 686                 }
 687                 if (hlen < obj_tlen)
 688                     break;
 689                 hlen -= obj_tlen;
 690                 obj_tptr += obj_tlen;
 691             }
 692         }
 693
 694         return;
 695 trunc:
 696         fputs("[|icmp]", stdout);
 697 }