dist/tcpdump/print-icmp.c

   1 /*      $NetBSD$        */
   2
   3 /*
   4  * Copyright (c) 1988, 1989, 1990, 1991, 1993, 1994, 1995, 1996
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that: (1) source code distributions
   9  * retain the above copyright notice and this paragraph in its entirety, (2)
  10  * distributions including binary code include the above copyright notice and
  11  * this paragraph in its entirety in the documentation or other materials
  12  * provided with the distribution, and (3) all advertising materials mentioning
  13  * features or use of this software display the following acknowledgement:
  14  * ``This product includes software developed by the University of California,
  15  * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
  16  * the University nor the names of its contributors may be used to endorse
  17  * or promote products derived from this software without specific prior
  18  * written permission.
  19  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
  20  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
  21  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  22  */
  23
  24 #include <sys/cdefs.h>
  25 #ifndef lint
  26 #if 0
  27 static const char rcsid[] _U_ =
  28     "@(#) Header: /tcpdump/master/tcpdump/print-icmp.c,v 1.81.2.4 2006/12/12 14:33:20 hannes Exp (LBL)";
  29 #else
  30 __RCSID("$NetBSD: tcpdump2rcsid.ex,v 1.1 2001/06/25 20:09:58 itojun Exp $");
  31 #endif
  32 #endif
  33
  34 #ifdef HAVE_CONFIG_H
  35 #include "config.h"
  36 #endif
  37
  38 #include <tcpdump-stdinc.h>
  39
  40 #include <stdio.h>
  41 #include <string.h>
  42
  43 #include "interface.h"
  44 #include "addrtoname.h"
  45 #include "extract.h"                    /* must come after interface.h */
  46
  47 #include "ip.h"
  48 #include "udp.h"
  49 #include "ipproto.h"
  50 #include "mpls.h"
  51
  52 /*
  53  * Interface Control Message Protocol Definitions.
  54  * Per RFC 792, September 1981.
  55  */
  56
  57 /*
  58  * Structure of an icmp header.
  59  */
  60 struct icmp {
  61         u_int8_t  icmp_type;            /* type of message, see below */
  62         u_int8_t  icmp_code;            /* type sub code */
  63         u_int16_t icmp_cksum;           /* ones complement cksum of struct */
  64         union {
  65                 u_int8_t ih_pptr;                       /* ICMP_PARAMPROB */
  66                 struct in_addr ih_gwaddr;       /* ICMP_REDIRECT */
  67                 struct ih_idseq {
  68                         u_int16_t icd_id;
  69                         u_int16_t icd_seq;
  70                 } ih_idseq;
  71                 u_int32_t ih_void;
  72         } icmp_hun;
  73 #define icmp_pptr       icmp_hun.ih_pptr
  74 #define icmp_gwaddr     icmp_hun.ih_gwaddr
  75 #define icmp_id         icmp_hun.ih_idseq.icd_id
  76 #define icmp_seq        icmp_hun.ih_idseq.icd_seq
  77 #define icmp_void       icmp_hun.ih_void
  78         union {
  79                 struct id_ts {
  80                         u_int32_t its_otime;
  81                         u_int32_t its_rtime;
  82                         u_int32_t its_ttime;
  83                 } id_ts;
  84                 struct id_ip  {
  85                         struct ip idi_ip;
  86                         /* options and then 64 bits of data */
  87                 } id_ip;
  88                 u_int32_t id_mask;
  89                 u_int8_t id_data[1];
  90         } icmp_dun;
  91 #define icmp_otime      icmp_dun.id_ts.its_otime
  92 #define icmp_rtime      icmp_dun.id_ts.its_rtime
  93 #define icmp_ttime      icmp_dun.id_ts.its_ttime
  94 #define icmp_ip         icmp_dun.id_ip.idi_ip
  95 #define icmp_mask       icmp_dun.id_mask
  96 #define icmp_data       icmp_dun.id_data
  97 };
  98
  99 #define ICMP_MPLS_EXT_EXTRACT_VERSION(x) (((x)&0xf0)>>4)
 100 #define ICMP_MPLS_EXT_VERSION 2
 101
 102 /*
 103  * Lower bounds on packet lengths for various types.
 104  * For the error advice packets must first insure that the
 105  * packet is large enought to contain the returned ip header.
 106  * Only then can we do the check to see if 64 bits of packet
 107  * data have been returned, since we need to check the returned
 108  * ip header length.
 109  */
 110 #define ICMP_MINLEN     8                               /* abs minimum */
 111 #define ICMP_EXTD_MINLEN (156 - sizeof (struct ip))     /* draft-bonica-internet-icmp-08 */
 112 #define ICMP_TSLEN      (8 + 3 * sizeof (u_int32_t))    /* timestamp */
 113 #define ICMP_MASKLEN    12                              /* address mask */
 114 #define ICMP_ADVLENMIN  (8 + sizeof (struct ip) + 8)    /* min */
 115 #define ICMP_ADVLEN(p)  (8 + (IP_HL(&(p)->icmp_ip) << 2) + 8)
 116         /* N.B.: must separately check that ip_hl >= 5 */
 117
 118 /*
 119  * Definition of type and code field values.
 120  */
 121 #define ICMP_ECHOREPLY          0               /* echo reply */
 122 #define ICMP_UNREACH            3               /* dest unreachable, codes: */
 123 #define         ICMP_UNREACH_NET        0               /* bad net */
 124 #define         ICMP_UNREACH_HOST       1               /* bad host */
 125 #define         ICMP_UNREACH_PROTOCOL   2               /* bad protocol */
 126 #define         ICMP_UNREACH_PORT       3               /* bad port */
 127 #define         ICMP_UNREACH_NEEDFRAG   4               /* IP_DF caused drop */
 128 #define         ICMP_UNREACH_SRCFAIL    5               /* src route failed */
 129 #define         ICMP_UNREACH_NET_UNKNOWN 6              /* unknown net */
 130 #define         ICMP_UNREACH_HOST_UNKNOWN 7             /* unknown host */
 131 #define         ICMP_UNREACH_ISOLATED   8               /* src host isolated */
 132 #define         ICMP_UNREACH_NET_PROHIB 9               /* prohibited access */
 133 #define         ICMP_UNREACH_HOST_PROHIB 10             /* ditto */
 134 #define         ICMP_UNREACH_TOSNET     11              /* bad tos for net */
 135 #define         ICMP_UNREACH_TOSHOST    12              /* bad tos for host */
 136 #define ICMP_SOURCEQUENCH       4               /* packet lost, slow down */
 137 #define ICMP_REDIRECT           5               /* shorter route, codes: */
 138 #define         ICMP_REDIRECT_NET       0               /* for network */
 139 #define         ICMP_REDIRECT_HOST      1               /* for host */
 140 #define         ICMP_REDIRECT_TOSNET    2               /* for tos and net */
 141 #define         ICMP_REDIRECT_TOSHOST   3               /* for tos and host */
 142 #define ICMP_ECHO               8               /* echo service */
 143 #define ICMP_ROUTERADVERT       9               /* router advertisement */
 144 #define ICMP_ROUTERSOLICIT      10              /* router solicitation */
 145 #define ICMP_TIMXCEED           11              /* time exceeded, code: */
 146 #define         ICMP_TIMXCEED_INTRANS   0               /* ttl==0 in transit */
 147 #define         ICMP_TIMXCEED_REASS     1               /* ttl==0 in reass */
 148 #define ICMP_PARAMPROB          12              /* ip header bad */
 149 #define         ICMP_PARAMPROB_OPTABSENT 1              /* req. opt. absent */
 150 #define ICMP_TSTAMP             13              /* timestamp request */
 151 #define ICMP_TSTAMPREPLY        14              /* timestamp reply */
 152 #define ICMP_IREQ               15              /* information request */
 153 #define ICMP_IREQREPLY          16              /* information reply */
 154 #define ICMP_MASKREQ            17              /* address mask request */
 155 #define ICMP_MASKREPLY          18              /* address mask reply */
 156
 157 #define ICMP_MAXTYPE            18
 158
 159 #define ICMP_INFOTYPE(type) \
 160         ((type) == ICMP_ECHOREPLY || (type) == ICMP_ECHO || \
 161         (type) == ICMP_ROUTERADVERT || (type) == ICMP_ROUTERSOLICIT || \
 162         (type) == ICMP_TSTAMP || (type) == ICMP_TSTAMPREPLY || \
 163         (type) == ICMP_IREQ || (type) == ICMP_IREQREPLY || \
 164         (type) == ICMP_MASKREQ || (type) == ICMP_MASKREPLY)
 165 #define ICMP_MPLS_EXT_TYPE(type) \
 166         ((type) == ICMP_UNREACH || \
 167          (type) == ICMP_TIMXCEED || \
 168          (type) == ICMP_PARAMPROB)
 169 /* rfc1700 */
 170 #ifndef ICMP_UNREACH_NET_UNKNOWN
 171 #define ICMP_UNREACH_NET_UNKNOWN        6       /* destination net unknown */
 172 #endif
 173 #ifndef ICMP_UNREACH_HOST_UNKNOWN
 174 #define ICMP_UNREACH_HOST_UNKNOWN       7       /* destination host unknown */
 175 #endif
 176 #ifndef ICMP_UNREACH_ISOLATED
 177 #define ICMP_UNREACH_ISOLATED           8       /* source host isolated */
 178 #endif
 179 #ifndef ICMP_UNREACH_NET_PROHIB
 180 #define ICMP_UNREACH_NET_PROHIB         9       /* admin prohibited net */
 181 #endif
 182 #ifndef ICMP_UNREACH_HOST_PROHIB
 183 #define ICMP_UNREACH_HOST_PROHIB        10      /* admin prohibited host */
 184 #endif
 185 #ifndef ICMP_UNREACH_TOSNET
 186 #define ICMP_UNREACH_TOSNET             11      /* tos prohibited net */
 187 #endif
 188 #ifndef ICMP_UNREACH_TOSHOST
 189 #define ICMP_UNREACH_TOSHOST            12      /* tos prohibited host */
 190 #endif
 191
 192 /* rfc1716 */
 193 #ifndef ICMP_UNREACH_FILTER_PROHIB
 194 #define ICMP_UNREACH_FILTER_PROHIB      13      /* admin prohibited filter */
 195 #endif
 196 #ifndef ICMP_UNREACH_HOST_PRECEDENCE
 197 #define ICMP_UNREACH_HOST_PRECEDENCE    14      /* host precedence violation */
 198 #endif
 199 #ifndef ICMP_UNREACH_PRECEDENCE_CUTOFF
 200 #define ICMP_UNREACH_PRECEDENCE_CUTOFF  15      /* precedence cutoff */
 201 #endif
 202
 203 /* Most of the icmp types */
 204 static struct tok icmp2str[] = {
 205         { ICMP_ECHOREPLY,               "echo reply" },
 206         { ICMP_SOURCEQUENCH,            "source quench" },
 207         { ICMP_ECHO,                    "echo request" },
 208         { ICMP_ROUTERSOLICIT,           "router solicitation" },
 209         { ICMP_TSTAMP,                  "time stamp request" },
 210         { ICMP_TSTAMPREPLY,             "time stamp reply" },
 211         { ICMP_IREQ,                    "information request" },
 212         { ICMP_IREQREPLY,               "information reply" },
 213         { ICMP_MASKREQ,                 "address mask request" },
 214         { 0,                            NULL }
 215 };
 216
 217 /* Formats for most of the ICMP_UNREACH codes */
 218 static struct tok unreach2str[] = {
 219         { ICMP_UNREACH_NET,             "net %s unreachable" },
 220         { ICMP_UNREACH_HOST,            "host %s unreachable" },
 221         { ICMP_UNREACH_SRCFAIL,
 222             "%s unreachable - source route failed" },
 223         { ICMP_UNREACH_NET_UNKNOWN,     "net %s unreachable - unknown" },
 224         { ICMP_UNREACH_HOST_UNKNOWN,    "host %s unreachable - unknown" },
 225         { ICMP_UNREACH_ISOLATED,
 226             "%s unreachable - source host isolated" },
 227         { ICMP_UNREACH_NET_PROHIB,
 228             "net %s unreachable - admin prohibited" },
 229         { ICMP_UNREACH_HOST_PROHIB,
 230             "host %s unreachable - admin prohibited" },
 231         { ICMP_UNREACH_TOSNET,
 232             "net %s unreachable - tos prohibited" },
 233         { ICMP_UNREACH_TOSHOST,
 234             "host %s unreachable - tos prohibited" },
 235         { ICMP_UNREACH_FILTER_PROHIB,
 236             "host %s unreachable - admin prohibited filter" },
 237         { ICMP_UNREACH_HOST_PRECEDENCE,
 238             "host %s unreachable - host precedence violation" },
 239         { ICMP_UNREACH_PRECEDENCE_CUTOFF,
 240             "host %s unreachable - precedence cutoff" },
 241         { 0,                            NULL }
 242 };
 243
 244 /* Formats for the ICMP_REDIRECT codes */
 245 static struct tok type2str[] = {
 246         { ICMP_REDIRECT_NET,            "redirect %s to net %s" },
 247         { ICMP_REDIRECT_HOST,           "redirect %s to host %s" },
 248         { ICMP_REDIRECT_TOSNET,         "redirect-tos %s to net %s" },
 249         { ICMP_REDIRECT_TOSHOST,        "redirect-tos %s to host %s" },
 250         { 0,                            NULL }
 251 };
 252
 253 /* rfc1191 */
 254 struct mtu_discovery {
 255         u_int16_t unused;
 256         u_int16_t nexthopmtu;
 257 };
 258
 259 /* rfc1256 */
 260 struct ih_rdiscovery {
 261         u_int8_t ird_addrnum;
 262         u_int8_t ird_addrsiz;
 263         u_int16_t ird_lifetime;
 264 };
 265
 266 struct id_rdiscovery {
 267         u_int32_t ird_addr;
 268         u_int32_t ird_pref;
 269 };
 270
 271 /*
 272  * draft-bonica-internet-icmp-08
 273  *
 274  * The Destination Unreachable, Time Exceeded
 275  * and Parameter Problem messages are slighly changed as per
 276  * the above draft. A new Length field gets added to give
 277  * the caller an idea about the length of the piggypacked
 278  * IP packet before the MPLS extension header starts.
 279  *
 280  * The Length field represents length of the padded "original datagram"
 281  * field  measured in 32-bit words.
 282  *
 283  * 0                   1                   2                   3
 284  * 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
 285  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 286  * |     Type      |     Code      |          Checksum             |
 287  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 288  * |     unused    |    Length     |          unused               |
 289  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 290  * |      Internet Header + leading octets of original datagram    |
 291  * |                                                               |
 292  * |                           //                                  |
 293  * |                                                               |
 294  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 295  */
 296
 297 struct icmp_ext_t {
 298     u_int8_t icmp_type;
 299     u_int8_t icmp_code;
 300     u_int8_t icmp_checksum[2];
 301     u_int8_t icmp_reserved;
 302     u_int8_t icmp_length;
 303     u_int8_t icmp_reserved2[2];
 304     u_int8_t icmp_ext_legacy_header[128]; /* extension header starts 128 bytes after ICMP header */
 305     u_int8_t icmp_ext_version_res[2];
 306     u_int8_t icmp_ext_checksum[2];
 307     u_int8_t icmp_ext_data[1];
 308 };
 309
 310 struct icmp_mpls_ext_common_header_t {
 311 };
 312
 313 struct icmp_mpls_ext_object_header_t {
 314     u_int8_t length[2];
 315     u_int8_t class_num;
 316     u_int8_t ctype;
 317 };
 318
 319 static const struct tok icmp_mpls_ext_obj_values[] = {
 320     { 1, "MPLS Stack Entry" },
 321     { 2, "Extended Payload" },
 322     { 0, NULL}
 323 };
 324
 325 /* prototypes */
 326 const char *icmp_tstamp_print(u_int);
 327
 328 /* print the milliseconds since midnight UTC */
 329 const char *
 330 icmp_tstamp_print(u_int tstamp) {
 331     u_int msec,sec,min,hrs;
 332
 333     static char buf[64];
 334
 335     msec = tstamp % 1000;
 336     sec = tstamp / 1000;
 337     min = sec / 60; sec -= min * 60;
 338     hrs = min / 60; min -= hrs * 60;
 339     snprintf(buf, sizeof(buf), "%02u:%02u:%02u.%03u",hrs,min,sec,msec);
 340     return buf;
 341 }
 342
 343 void
 344 icmp_print(const u_char *bp, u_int plen, const u_char *bp2, int fragmented)
 345 {
 346         char *cp;
 347         const struct icmp *dp;
 348         const struct icmp_ext_t *ext_dp;
 349         const struct ip *ip;
 350         const char *str, *fmt;
 351         const struct ip *oip;
 352         const struct udphdr *ouh;
 353         const u_int8_t *obj_tptr;
 354         u_int32_t raw_label;
 355         const u_char *snapend_save;
 356         const struct icmp_mpls_ext_object_header_t *icmp_mpls_ext_object_header;
 357         u_int hlen, dport, mtu, obj_tlen, obj_class_num, obj_ctype;
 358         char buf[MAXHOSTNAMELEN + 100];
 359
 360         dp = (struct icmp *)bp;
 361         ext_dp = (struct icmp_ext_t *)bp;
 362         ip = (struct ip *)bp2;
 363         str = buf;
 364
 365         TCHECK(dp->icmp_code);
 366         switch (dp->icmp_type) {
 367
 368         case ICMP_ECHO:
 369         case ICMP_ECHOREPLY:
 370                 TCHECK(dp->icmp_seq);
 371                 (void)snprintf(buf, sizeof(buf), "echo %s, id %u, seq %u",
 372                                dp->icmp_type == ICMP_ECHO ?
 373                                "request" : "reply",
 374                                EXTRACT_16BITS(&dp->icmp_id),
 375                                EXTRACT_16BITS(&dp->icmp_seq));
 376                 break;
 377
 378         case ICMP_UNREACH:
 379                 TCHECK(dp->icmp_ip.ip_dst);
 380                 switch (dp->icmp_code) {
 381
 382                 case ICMP_UNREACH_PROTOCOL:
 383                         TCHECK(dp->icmp_ip.ip_p);
 384                         (void)snprintf(buf, sizeof(buf),
 385                             "%s protocol %d unreachable",
 386                             ipaddr_string(&dp->icmp_ip.ip_dst),
 387                             dp->icmp_ip.ip_p);
 388                         break;
 389
 390                 case ICMP_UNREACH_PORT:
 391                         TCHECK(dp->icmp_ip.ip_p);
 392                         oip = &dp->icmp_ip;
 393                         hlen = IP_HL(oip) * 4;
 394                         ouh = (struct udphdr *)(((u_char *)oip) + hlen);
 395                         TCHECK(ouh->uh_dport);
 396                         dport = EXTRACT_16BITS(&ouh->uh_dport);
 397                         switch (oip->ip_p) {
 398
 399                         case IPPROTO_TCP:
 400                                 (void)snprintf(buf, sizeof(buf),
 401                                         "%s tcp port %s unreachable",
 402                                         ipaddr_string(&oip->ip_dst),
 403                                         tcpport_string(dport));
 404                                 break;
 405
 406                         case IPPROTO_UDP:
 407                                 (void)snprintf(buf, sizeof(buf),
 408                                         "%s udp port %s unreachable",
 409                                         ipaddr_string(&oip->ip_dst),
 410                                         udpport_string(dport));
 411                                 break;
 412
 413                         default:
 414                                 (void)snprintf(buf, sizeof(buf),
 415                                         "%s protocol %d port %d unreachable",
 416                                         ipaddr_string(&oip->ip_dst),
 417                                         oip->ip_p, dport);
 418                                 break;
 419                         }
 420                         break;
 421
 422                 case ICMP_UNREACH_NEEDFRAG:
 423                     {
 424                         register const struct mtu_discovery *mp;
 425                         mp = (struct mtu_discovery *)&dp->icmp_void;
 426                         mtu = EXTRACT_16BITS(&mp->nexthopmtu);
 427                         if (mtu) {
 428                                 (void)snprintf(buf, sizeof(buf),
 429                                     "%s unreachable - need to frag (mtu %d)",
 430                                     ipaddr_string(&dp->icmp_ip.ip_dst), mtu);
 431                         } else {
 432                                 (void)snprintf(buf, sizeof(buf),
 433                                     "%s unreachable - need to frag",
 434                                     ipaddr_string(&dp->icmp_ip.ip_dst));
 435                         }
 436                     }
 437                         break;
 438
 439                 default:
 440                         fmt = tok2str(unreach2str, "#%d %%s unreachable",
 441                             dp->icmp_code);
 442                         (void)snprintf(buf, sizeof(buf), fmt,
 443                             ipaddr_string(&dp->icmp_ip.ip_dst));
 444                         break;
 445                 }
 446                 break;
 447
 448         case ICMP_REDIRECT:
 449                 TCHECK(dp->icmp_ip.ip_dst);
 450                 fmt = tok2str(type2str, "redirect-#%d %%s to net %%s",
 451                     dp->icmp_code);
 452                 (void)snprintf(buf, sizeof(buf), fmt,
 453                     ipaddr_string(&dp->icmp_ip.ip_dst),
 454                     ipaddr_string(&dp->icmp_gwaddr));
 455                 break;
 456
 457         case ICMP_ROUTERADVERT:
 458             {
 459                 register const struct ih_rdiscovery *ihp;
 460                 register const struct id_rdiscovery *idp;
 461                 u_int lifetime, num, size;
 462
 463                 (void)snprintf(buf, sizeof(buf), "router advertisement");
 464                 cp = buf + strlen(buf);
 465
 466                 ihp = (struct ih_rdiscovery *)&dp->icmp_void;
 467                 TCHECK(*ihp);
 468                 (void)strncpy(cp, " lifetime ", sizeof(buf) - (cp - buf));
 469                 cp = buf + strlen(buf);
 470                 lifetime = EXTRACT_16BITS(&ihp->ird_lifetime);
 471                 if (lifetime < 60) {
 472                         (void)snprintf(cp, sizeof(buf) - (cp - buf), "%u",
 473                             lifetime);
 474                 } else if (lifetime < 60 * 60) {
 475                         (void)snprintf(cp, sizeof(buf) - (cp - buf), "%u:%02u",
 476                             lifetime / 60, lifetime % 60);
 477                 } else {
 478                         (void)snprintf(cp, sizeof(buf) - (cp - buf),
 479                             "%u:%02u:%02u",
 480                             lifetime / 3600,
 481                             (lifetime % 3600) / 60,
 482                             lifetime % 60);
 483                 }
 484                 cp = buf + strlen(buf);
 485
 486                 num = ihp->ird_addrnum;
 487                 (void)snprintf(cp, sizeof(buf) - (cp - buf), " %d:", num);
 488                 cp = buf + strlen(buf);
 489
 490                 size = ihp->ird_addrsiz;
 491                 if (size != 2) {
 492                         (void)snprintf(cp, sizeof(buf) - (cp - buf),
 493                             " [size %d]", size);
 494                         break;
 495                 }
 496                 idp = (struct id_rdiscovery *)&dp->icmp_data;
 497                 while (num-- > 0) {
 498                         TCHECK(*idp);
 499                         (void)snprintf(cp, sizeof(buf) - (cp - buf), " {%s %u}",
 500                             ipaddr_string(&idp->ird_addr),
 501                             EXTRACT_32BITS(&idp->ird_pref));
 502                         cp = buf + strlen(buf);
 503                         ++idp;
 504                 }
 505             }
 506                 break;
 507
 508         case ICMP_TIMXCEED:
 509                 TCHECK(dp->icmp_ip.ip_dst);
 510                 switch (dp->icmp_code) {
 511
 512                 case ICMP_TIMXCEED_INTRANS:
 513                         str = "time exceeded in-transit";
 514                         break;
 515
 516                 case ICMP_TIMXCEED_REASS:
 517                         str = "ip reassembly time exceeded";
 518                         break;
 519
 520                 default:
 521                         (void)snprintf(buf, sizeof(buf), "time exceeded-#%d",
 522                             dp->icmp_code);
 523                         break;
 524                 }
 525                 break;
 526
 527         case ICMP_PARAMPROB:
 528                 if (dp->icmp_code)
 529                         (void)snprintf(buf, sizeof(buf),
 530                             "parameter problem - code %d", dp->icmp_code);
 531                 else {
 532                         TCHECK(dp->icmp_pptr);
 533                         (void)snprintf(buf, sizeof(buf),
 534                             "parameter problem - octet %d", dp->icmp_pptr);
 535                 }
 536                 break;
 537
 538         case ICMP_MASKREPLY:
 539                 TCHECK(dp->icmp_mask);
 540                 (void)snprintf(buf, sizeof(buf), "address mask is 0x%08x",
 541                     EXTRACT_32BITS(&dp->icmp_mask));
 542                 break;
 543
 544         case ICMP_TSTAMP:
 545                 TCHECK(dp->icmp_seq);
 546                 (void)snprintf(buf, sizeof(buf),
 547                     "time stamp query id %u seq %u",
 548                     EXTRACT_16BITS(&dp->icmp_id),
 549                     EXTRACT_16BITS(&dp->icmp_seq));
 550                 break;
 551
 552         case ICMP_TSTAMPREPLY:
 553                 TCHECK(dp->icmp_ttime);
 554                 (void)snprintf(buf, sizeof(buf),
 555                     "time stamp reply id %u seq %u: org %s",
 556                                EXTRACT_16BITS(&dp->icmp_id),
 557                                EXTRACT_16BITS(&dp->icmp_seq),
 558                                icmp_tstamp_print(EXTRACT_32BITS(&dp->icmp_otime)));
 559
 560                 (void)snprintf(buf+strlen(buf),sizeof(buf)-strlen(buf),", recv %s",
 561                          icmp_tstamp_print(EXTRACT_32BITS(&dp->icmp_rtime)));
 562                 (void)snprintf(buf+strlen(buf),sizeof(buf)-strlen(buf),", xmit %s",
 563                          icmp_tstamp_print(EXTRACT_32BITS(&dp->icmp_ttime)));
 564                 break;
 565
 566         default:
 567                 str = tok2str(icmp2str, "type-#%d", dp->icmp_type);
 568                 break;
 569         }
 570         (void)printf("ICMP %s, length %u", str, plen);
 571         if (vflag && !fragmented) { /* don't attempt checksumming if this is a frag */
 572                 u_int16_t sum, icmp_sum;
 573                 if (TTEST2(*bp, plen)) {
 574                         sum = in_cksum((u_short*)dp, plen, 0);
 575                         if (sum != 0) {
 576                                 icmp_sum = EXTRACT_16BITS(&dp->icmp_cksum);
 577                                 (void)printf(" (wrong icmp cksum %x (->%x)!)",
 578                                              icmp_sum,
 579                                              in_cksum_shouldbe(icmp_sum, sum));
 580                         }
 581                 }
 582         }
 583
 584         /*
 585          * print the remnants of the IP packet.
 586          * save the snaplength as this may get overidden in the IP printer.
 587          */
 588         if (vflag >= 1 && !ICMP_INFOTYPE(dp->icmp_type)) {
 589                 bp += 8;
 590                 (void)printf("\n\t");
 591                 ip = (struct ip *)bp;
 592                 snaplen = snapend - bp;
 593                 snapend_save = snapend;
 594                 ip_print(gndo, bp, EXTRACT_16BITS(&ip->ip_len));
 595                 snapend = snapend_save;
 596         }
 597
 598         /*
 599          * Attempt to decode the MPLS extensions only for some ICMP types.
 600          */
 601         if (vflag >= 1 && plen > ICMP_EXTD_MINLEN && ICMP_MPLS_EXT_TYPE(dp->icmp_type)) {
 602
 603             TCHECK(*ext_dp);
 604
 605             /*
 606              * Check first if the mpls extension header shows a non-zero length.
 607              * If the length field is not set then silently verify the checksum
 608              * to check if an extension header is present. This is expedient,
 609              * however not all implementations set the length field proper.
 610              */
 611             if (!ext_dp->icmp_length &&
 612                 in_cksum((const u_short *)&ext_dp->icmp_ext_version_res,
 613                          plen - ICMP_EXTD_MINLEN, 0)) {
 614                 return;
 615             }
 616
 617             printf("\n\tMPLS extension v%u",
 618                    ICMP_MPLS_EXT_EXTRACT_VERSION(*(ext_dp->icmp_ext_version_res)));
 619
 620             /*
 621              * Sanity checking of the header.
 622              */
 623             if (ICMP_MPLS_EXT_EXTRACT_VERSION(*(ext_dp->icmp_ext_version_res)) !=
 624                 ICMP_MPLS_EXT_VERSION) {
 625                 printf(" packet not supported");
 626                 return;
 627             }
 628
 629             hlen = plen - ICMP_EXTD_MINLEN;
 630             printf(", checksum 0x%04x (%scorrect), length %u",
 631                    EXTRACT_16BITS(ext_dp->icmp_ext_checksum),
 632                    in_cksum((const u_short *)&ext_dp->icmp_ext_version_res,
 633                             plen - ICMP_EXTD_MINLEN, 0) ? "in" : "",
 634                    hlen);
 635
 636             hlen -= 4; /* subtract common header size */
 637             obj_tptr = (u_int8_t *)ext_dp->icmp_ext_data;
 638
 639             while (hlen > sizeof(struct icmp_mpls_ext_object_header_t)) {
 640
 641                 icmp_mpls_ext_object_header = (struct icmp_mpls_ext_object_header_t *)obj_tptr;
 642                 TCHECK(*icmp_mpls_ext_object_header);
 643                 obj_tlen = EXTRACT_16BITS(icmp_mpls_ext_object_header->length);
 644                 obj_class_num = icmp_mpls_ext_object_header->class_num;
 645                 obj_ctype = icmp_mpls_ext_object_header->ctype;
 646                 obj_tptr += sizeof(struct icmp_mpls_ext_object_header_t);
 647
 648                 printf("\n\t  %s Object (%u), Class-Type: %u, length %u",
 649                        tok2str(icmp_mpls_ext_obj_values,"unknown",obj_class_num),
 650                        obj_class_num,
 651                        obj_ctype,
 652                        obj_tlen);
 653
 654                 hlen-=sizeof(struct icmp_mpls_ext_object_header_t); /* length field includes tlv header */
 655
 656                 /* infinite loop protection */
 657                 if ((obj_class_num == 0) ||
 658                     (obj_tlen < sizeof(struct icmp_mpls_ext_object_header_t))) {
 659                     return;
 660                 }
 661                 obj_tlen-=sizeof(struct icmp_mpls_ext_object_header_t);
 662
 663                 switch (obj_class_num) {
 664                 case 1:
 665                     switch(obj_ctype) {
 666                     case 1:
 667                         TCHECK2(*obj_tptr, 4);
 668                         raw_label = EXTRACT_32BITS(obj_tptr);
 669                         printf("\n\t    label %u, exp %u", MPLS_LABEL(raw_label), MPLS_EXP(raw_label));
 670                         if (MPLS_STACK(raw_label))
 671                             printf(", [S]");
 672                         printf(", ttl %u", MPLS_TTL(raw_label));
 673                         break;
 674                     default:
 675                         print_unknown_data(obj_tptr, "\n\t    ", obj_tlen);
 676                     }
 677                     break;
 678
 679                /*
 680                 *  FIXME those are the defined objects that lack a decoder
 681                 *  you are welcome to contribute code ;-)
 682                 */
 683                 case 2:
 684                 default:
 685                     print_unknown_data(obj_tptr, "\n\t    ", obj_tlen);
 686                     break;
 687                 }
 688                 if (hlen < obj_tlen)
 689                     break;
 690                 hlen -= obj_tlen;
 691                 obj_tptr += obj_tlen;
 692             }
 693         }
 694
 695         return;
 696 trunc:
 697         fputs("[|icmp]", stdout);
 698 }