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
  22 /* \summary: Internet Control Message Protocol (ICMP) printer */
  23
  24 #ifdef HAVE_CONFIG_H
  25 #include <config.h>
  26 #endif
  27
  28 #include "netdissect-stdinc.h"
  29
  30 #include <stdio.h>
  31 #include <string.h>
  32
  33 #include "netdissect.h"
  34 #include "addrtoname.h"
  35 #include "extract.h"
  36
  37 #include "ip.h"
  38 #include "udp.h"
  39 #include "ipproto.h"
  40 #include "mpls.h"
  41
  42 /*
  43  * Interface Control Message Protocol Definitions.
  44  * Per RFC 792, September 1981.
  45  */
  46
  47 /*
  48  * Structure of an icmp header.
  49  */
  50 struct icmp {
  51         nd_uint8_t  icmp_type;          /* type of message, see below */
  52         nd_uint8_t  icmp_code;          /* type sub code */
  53         nd_uint16_t icmp_cksum;         /* ones complement cksum of struct */
  54         union {
  55                 nd_uint8_t ih_pptr;     /* ICMP_PARAMPROB */
  56                 nd_ipv4 ih_gwaddr;      /* ICMP_REDIRECT */
  57                 struct ih_idseq {
  58                         nd_uint16_t icd_id;
  59                         nd_uint16_t icd_seq;
  60                 } ih_idseq;
  61                 nd_uint32_t ih_void;
  62         } icmp_hun;
  63 #define icmp_pptr       icmp_hun.ih_pptr
  64 #define icmp_gwaddr     icmp_hun.ih_gwaddr
  65 #define icmp_id         icmp_hun.ih_idseq.icd_id
  66 #define icmp_seq        icmp_hun.ih_idseq.icd_seq
  67 #define icmp_void       icmp_hun.ih_void
  68         union {
  69                 struct id_ts {
  70                         nd_uint32_t its_otime;
  71                         nd_uint32_t its_rtime;
  72                         nd_uint32_t its_ttime;
  73                 } id_ts;
  74                 struct id_ip  {
  75                         struct ip idi_ip;
  76                         /* options and then 64 bits of data */
  77                 } id_ip;
  78                 nd_uint32_t id_mask;
  79                 nd_byte id_data[1];
  80         } icmp_dun;
  81 #define icmp_otime      icmp_dun.id_ts.its_otime
  82 #define icmp_rtime      icmp_dun.id_ts.its_rtime
  83 #define icmp_ttime      icmp_dun.id_ts.its_ttime
  84 #define icmp_ip         icmp_dun.id_ip.idi_ip
  85 #define icmp_mask       icmp_dun.id_mask
  86 #define icmp_data       icmp_dun.id_data
  87 };
  88
  89 /*
  90  * Lower bounds on packet lengths for various types.
  91  * For the error advice packets must first insure that the
  92  * packet is large enough to contain the returned ip header.
  93  * Only then can we do the check to see if 64 bits of packet
  94  * data have been returned, since we need to check the returned
  95  * ip header length.
  96  */
  97 #define ICMP_MINLEN     8                               /* abs minimum */
  98 #define ICMP_EXTD_MINLEN (156 - sizeof (struct ip))     /* draft-bonica-internet-icmp-08 */
  99 #define ICMP_TSLEN      (8 + 3 * sizeof (uint32_t))     /* timestamp */
 100 #define ICMP_MASKLEN    12                              /* address mask */
 101 #define ICMP_ADVLENMIN  (8 + sizeof (struct ip) + 8)    /* min */
 102 #define ICMP_ADVLEN(p)  (8 + (IP_HL(&(p)->icmp_ip) << 2) + 8)
 103         /* N.B.: must separately check that ip_hl >= 5 */
 104
 105 /*
 106  * Definition of type and code field values.
 107  */
 108 #define ICMP_ECHOREPLY          0               /* echo reply */
 109 #define ICMP_UNREACH            3               /* dest unreachable, codes: */
 110 #define         ICMP_UNREACH_NET        0               /* bad net */
 111 #define         ICMP_UNREACH_HOST       1               /* bad host */
 112 #define         ICMP_UNREACH_PROTOCOL   2               /* bad protocol */
 113 #define         ICMP_UNREACH_PORT       3               /* bad port */
 114 #define         ICMP_UNREACH_NEEDFRAG   4               /* IP_DF caused drop */
 115 #define         ICMP_UNREACH_SRCFAIL    5               /* src route failed */
 116 #define         ICMP_UNREACH_NET_UNKNOWN 6              /* unknown net */
 117 #define         ICMP_UNREACH_HOST_UNKNOWN 7             /* unknown host */
 118 #define         ICMP_UNREACH_ISOLATED   8               /* src host isolated */
 119 #define         ICMP_UNREACH_NET_PROHIB 9               /* prohibited access */
 120 #define         ICMP_UNREACH_HOST_PROHIB 10             /* ditto */
 121 #define         ICMP_UNREACH_TOSNET     11              /* bad tos for net */
 122 #define         ICMP_UNREACH_TOSHOST    12              /* bad tos for host */
 123 #define ICMP_SOURCEQUENCH       4               /* packet lost, slow down */
 124 #define ICMP_REDIRECT           5               /* shorter route, codes: */
 125 #define         ICMP_REDIRECT_NET       0               /* for network */
 126 #define         ICMP_REDIRECT_HOST      1               /* for host */
 127 #define         ICMP_REDIRECT_TOSNET    2               /* for tos and net */
 128 #define         ICMP_REDIRECT_TOSHOST   3               /* for tos and host */
 129 #define ICMP_ECHO               8               /* echo service */
 130 #define ICMP_ROUTERADVERT       9               /* router advertisement */
 131 #define ICMP_ROUTERSOLICIT      10              /* router solicitation */
 132 #define ICMP_TIMXCEED           11              /* time exceeded, code: */
 133 #define         ICMP_TIMXCEED_INTRANS   0               /* ttl==0 in transit */
 134 #define         ICMP_TIMXCEED_REASS     1               /* ttl==0 in reass */
 135 #define ICMP_PARAMPROB          12              /* ip header bad */
 136 #define         ICMP_PARAMPROB_OPTABSENT 1              /* req. opt. absent */
 137 #define ICMP_TSTAMP             13              /* timestamp request */
 138 #define ICMP_TSTAMPREPLY        14              /* timestamp reply */
 139 #define ICMP_IREQ               15              /* information request */
 140 #define ICMP_IREQREPLY          16              /* information reply */
 141 #define ICMP_MASKREQ            17              /* address mask request */
 142 #define ICMP_MASKREPLY          18              /* address mask reply */
 143
 144 #define ICMP_MAXTYPE            18
 145
 146 #define ICMP_ERRTYPE(type) \
 147         ((type) == ICMP_UNREACH || (type) == ICMP_SOURCEQUENCH || \
 148         (type) == ICMP_REDIRECT || (type) == ICMP_TIMXCEED || \
 149         (type) == ICMP_PARAMPROB)
 150 #define ICMP_MULTIPART_EXT_TYPE(type) \
 151         ((type) == ICMP_UNREACH || \
 152          (type) == ICMP_TIMXCEED || \
 153          (type) == ICMP_PARAMPROB)
 154 /* rfc1700 */
 155 #ifndef ICMP_UNREACH_NET_UNKNOWN
 156 #define ICMP_UNREACH_NET_UNKNOWN        6       /* destination net unknown */
 157 #endif
 158 #ifndef ICMP_UNREACH_HOST_UNKNOWN
 159 #define ICMP_UNREACH_HOST_UNKNOWN       7       /* destination host unknown */
 160 #endif
 161 #ifndef ICMP_UNREACH_ISOLATED
 162 #define ICMP_UNREACH_ISOLATED           8       /* source host isolated */
 163 #endif
 164 #ifndef ICMP_UNREACH_NET_PROHIB
 165 #define ICMP_UNREACH_NET_PROHIB         9       /* admin prohibited net */
 166 #endif
 167 #ifndef ICMP_UNREACH_HOST_PROHIB
 168 #define ICMP_UNREACH_HOST_PROHIB        10      /* admin prohibited host */
 169 #endif
 170 #ifndef ICMP_UNREACH_TOSNET
 171 #define ICMP_UNREACH_TOSNET             11      /* tos prohibited net */
 172 #endif
 173 #ifndef ICMP_UNREACH_TOSHOST
 174 #define ICMP_UNREACH_TOSHOST            12      /* tos prohibited host */
 175 #endif
 176
 177 /* rfc1716 */
 178 #ifndef ICMP_UNREACH_FILTER_PROHIB
 179 #define ICMP_UNREACH_FILTER_PROHIB      13      /* admin prohibited filter */
 180 #endif
 181 #ifndef ICMP_UNREACH_HOST_PRECEDENCE
 182 #define ICMP_UNREACH_HOST_PRECEDENCE    14      /* host precedence violation */
 183 #endif
 184 #ifndef ICMP_UNREACH_PRECEDENCE_CUTOFF
 185 #define ICMP_UNREACH_PRECEDENCE_CUTOFF  15      /* precedence cutoff */
 186 #endif
 187
 188 /* Most of the icmp types */
 189 static const struct tok icmp2str[] = {
 190         { ICMP_ECHOREPLY,               "echo reply" },
 191         { ICMP_SOURCEQUENCH,            "source quench" },
 192         { ICMP_ECHO,                    "echo request" },
 193         { ICMP_ROUTERSOLICIT,           "router solicitation" },
 194         { ICMP_TSTAMP,                  "time stamp request" },
 195         { ICMP_TSTAMPREPLY,             "time stamp reply" },
 196         { ICMP_IREQ,                    "information request" },
 197         { ICMP_IREQREPLY,               "information reply" },
 198         { ICMP_MASKREQ,                 "address mask request" },
 199         { 0,                            NULL }
 200 };
 201
 202 /* rfc1191 */
 203 struct mtu_discovery {
 204         nd_uint16_t unused;
 205         nd_uint16_t nexthopmtu;
 206 };
 207
 208 /* rfc1256 */
 209 struct ih_rdiscovery {
 210         nd_uint8_t ird_addrnum;
 211         nd_uint8_t ird_addrsiz;
 212         nd_uint16_t ird_lifetime;
 213 };
 214
 215 struct id_rdiscovery {
 216         nd_uint32_t ird_addr;
 217         nd_uint32_t ird_pref;
 218 };
 219
 220 /*
 221  * RFC 4884 - Extended ICMP to Support Multi-Part Messages
 222  *
 223  * This is a general extension mechanism, based on the mechanism
 224  * in draft-bonica-icmp-mpls-02 ICMP Extensions for MultiProtocol
 225  * Label Switching.
 226  *
 227  * The Destination Unreachable, Time Exceeded
 228  * and Parameter Problem messages are slightly changed as per
 229  * the above RFC. A new Length field gets added to give
 230  * the caller an idea about the length of the piggybacked
 231  * IP packet before the extension header starts.
 232  *
 233  * The Length field represents length of the padded "original datagram"
 234  * field  measured in 32-bit words.
 235  *
 236  * 0                   1                   2                   3
 237  * 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
 238  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 239  * |     Type      |     Code      |          Checksum             |
 240  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 241  * |     unused    |    Length     |          unused               |
 242  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 243  * |      Internet Header + leading octets of original datagram    |
 244  * |                                                               |
 245  * |                           //                                  |
 246  * |                                                               |
 247  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 248  */
 249
 250 struct icmp_ext_t {
 251     nd_uint8_t  icmp_type;
 252     nd_uint8_t  icmp_code;
 253     nd_uint16_t icmp_checksum;
 254     nd_byte     icmp_reserved;
 255     nd_uint8_t  icmp_length;
 256     nd_byte     icmp_reserved2[2];
 257     nd_byte     icmp_ext_legacy_header[128]; /* extension header starts 128 bytes after ICMP header */
 258     nd_byte     icmp_ext_version_res[2];
 259     nd_uint16_t icmp_ext_checksum;
 260     nd_byte     icmp_ext_data[1];
 261 };
 262
 263 /*
 264  * Extract version from the first octet of icmp_ext_version_res.
 265  */
 266 #define ICMP_EXT_EXTRACT_VERSION(x) (((x)&0xf0)>>4)
 267
 268 /*
 269  * Current version.
 270  */
 271 #define ICMP_EXT_VERSION 2
 272
 273 /*
 274  * Extension object class numbers.
 275  *
 276  * Class 1 dates back to draft-bonica-icmp-mpls-02.
 277  */
 278
 279 /* rfc4950  */
 280 #define MPLS_STACK_ENTRY_OBJECT_CLASS            1
 281
 282 struct icmp_multipart_ext_object_header_t {
 283     nd_uint16_t length;
 284     nd_uint8_t  class_num;
 285     nd_uint8_t  ctype;
 286 };
 287
 288 static const struct tok icmp_multipart_ext_obj_values[] = {
 289     { 1, "MPLS Stack Entry" },
 290     { 2, "Interface Identification" },
 291     { 0, NULL}
 292 };
 293
 294 /* prototypes */
 295 const char *icmp_tstamp_print(u_int);
 296
 297 /* print the milliseconds since midnight UTC */
 298 const char *
 299 icmp_tstamp_print(u_int tstamp)
 300 {
 301     u_int msec,sec,min,hrs;
 302
 303     static char buf[64];
 304
 305     msec = tstamp % 1000;
 306     sec = tstamp / 1000;
 307     min = sec / 60; sec -= min * 60;
 308     hrs = min / 60; min -= hrs * 60;
 309     snprintf(buf, sizeof(buf), "%02u:%02u:%02u.%03u",hrs,min,sec,msec);
 310     return buf;
 311 }
 312
 313 void
 314 icmp_print(netdissect_options *ndo, const u_char *bp, u_int plen, const u_char *bp2,
 315            int fragmented)
 316 {
 317         char *cp;
 318         const struct icmp *dp;
 319         uint8_t icmp_type, icmp_code;
 320         const struct icmp_ext_t *ext_dp;
 321         const struct ip *ip;
 322         const char *str;
 323         const struct ip *oip;
 324         uint8_t ip_proto;
 325         const struct udphdr *ouh;
 326         const uint8_t *obj_tptr;
 327         uint32_t raw_label;
 328         const struct icmp_multipart_ext_object_header_t *icmp_multipart_ext_object_header;
 329         u_int hlen, mtu, obj_tlen, obj_class_num, obj_ctype;
 330         uint16_t dport;
 331         char buf[MAXHOSTNAMELEN + 100];
 332         struct cksum_vec vec[1];
 333
 334         ndo->ndo_protocol = "icmp";
 335         dp = (const struct icmp *)bp;
 336         ext_dp = (const struct icmp_ext_t *)bp;
 337         ip = (const struct ip *)bp2;
 338         str = buf;
 339
 340         icmp_type = GET_U_1(dp->icmp_type);
 341         icmp_code = GET_U_1(dp->icmp_code);
 342         switch (icmp_type) {
 343
 344         case ICMP_ECHO:
 345         case ICMP_ECHOREPLY:
 346                 (void)snprintf(buf, sizeof(buf), "echo %s, id %u, seq %u",
 347                                icmp_type == ICMP_ECHO ?
 348                                "request" : "reply",
 349                                GET_BE_U_2(dp->icmp_id),
 350                                GET_BE_U_2(dp->icmp_seq));
 351                 break;
 352
 353         case ICMP_UNREACH:
 354                 switch (icmp_code) {
 355
 356                 case ICMP_UNREACH_NET:
 357                         (void)snprintf(buf, sizeof(buf),
 358                             "net %s unreachable",
 359                             GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
 360                         break;
 361
 362                 case ICMP_UNREACH_HOST:
 363                         (void)snprintf(buf, sizeof(buf),
 364                             "host %s unreachable",
 365                             GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
 366                         break;
 367
 368                 case ICMP_UNREACH_PROTOCOL:
 369                         (void)snprintf(buf, sizeof(buf),
 370                             "%s protocol %u unreachable",
 371                             GET_IPADDR_STRING(dp->icmp_ip.ip_dst),
 372                             GET_U_1(dp->icmp_ip.ip_p));
 373                         break;
 374
 375                 case ICMP_UNREACH_PORT:
 376                         ND_TCHECK_1(dp->icmp_ip.ip_p);
 377                         oip = &dp->icmp_ip;
 378                         hlen = IP_HL(oip) * 4;
 379                         ouh = (const struct udphdr *)(((const u_char *)oip) + hlen);
 380                         dport = GET_BE_U_2(ouh->uh_dport);
 381                         ip_proto = GET_U_1(oip->ip_p);
 382                         switch (ip_proto) {
 383
 384                         case IPPROTO_TCP:
 385                                 (void)snprintf(buf, sizeof(buf),
 386                                         "%s tcp port %s unreachable",
 387                                         GET_IPADDR_STRING(oip->ip_dst),
 388                                         tcpport_string(ndo, dport));
 389                                 break;
 390
 391                         case IPPROTO_UDP:
 392                                 (void)snprintf(buf, sizeof(buf),
 393                                         "%s udp port %s unreachable",
 394                                         GET_IPADDR_STRING(oip->ip_dst),
 395                                         udpport_string(ndo, dport));
 396                                 break;
 397
 398                         default:
 399                                 (void)snprintf(buf, sizeof(buf),
 400                                         "%s protocol %u port %u unreachable",
 401                                         GET_IPADDR_STRING(oip->ip_dst),
 402                                         ip_proto, dport);
 403                                 break;
 404                         }
 405                         break;
 406
 407                 case ICMP_UNREACH_NEEDFRAG:
 408                     {
 409                         const struct mtu_discovery *mp;
 410                         mp = (const struct mtu_discovery *)(const u_char *)&dp->icmp_void;
 411                         mtu = GET_BE_U_2(mp->nexthopmtu);
 412                         if (mtu) {
 413                                 (void)snprintf(buf, sizeof(buf),
 414                                     "%s unreachable - need to frag (mtu %u)",
 415                                     GET_IPADDR_STRING(dp->icmp_ip.ip_dst), mtu);
 416                         } else {
 417                                 (void)snprintf(buf, sizeof(buf),
 418                                     "%s unreachable - need to frag",
 419                                     GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
 420                         }
 421                     }
 422                         break;
 423
 424                 case ICMP_UNREACH_SRCFAIL:
 425                         (void)snprintf(buf, sizeof(buf),
 426                             "%s unreachable - source route failed",
 427                             GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
 428                         break;
 429
 430                 case ICMP_UNREACH_NET_UNKNOWN:
 431                         (void)snprintf(buf, sizeof(buf),
 432                             "net %s unreachable - unknown",
 433                             GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
 434                         break;
 435
 436                 case ICMP_UNREACH_HOST_UNKNOWN:
 437                         (void)snprintf(buf, sizeof(buf),
 438                             "host %s unreachable - unknown",
 439                             GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
 440                         break;
 441
 442                 case ICMP_UNREACH_ISOLATED:
 443                         (void)snprintf(buf, sizeof(buf),
 444                             "%s unreachable - source host isolated",
 445                             GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
 446                         break;
 447
 448                 case ICMP_UNREACH_NET_PROHIB:
 449                         (void)snprintf(buf, sizeof(buf),
 450                             "net %s unreachable - admin prohibited",
 451                             GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
 452                         break;
 453
 454                 case ICMP_UNREACH_HOST_PROHIB:
 455                         (void)snprintf(buf, sizeof(buf),
 456                             "host %s unreachable - admin prohibited",
 457                             GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
 458                         break;
 459
 460                 case ICMP_UNREACH_TOSNET:
 461                         (void)snprintf(buf, sizeof(buf),
 462                             "net %s unreachable - tos prohibited",
 463                             GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
 464                         break;
 465
 466                 case ICMP_UNREACH_TOSHOST:
 467                         (void)snprintf(buf, sizeof(buf),
 468                             "host %s unreachable - tos prohibited",
 469                             GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
 470                         break;
 471
 472                 case ICMP_UNREACH_FILTER_PROHIB:
 473                         (void)snprintf(buf, sizeof(buf),
 474                             "host %s unreachable - admin prohibited filter",
 475                             GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
 476                         break;
 477
 478                 case ICMP_UNREACH_HOST_PRECEDENCE:
 479                         (void)snprintf(buf, sizeof(buf),
 480                             "host %s unreachable - host precedence violation",
 481                             GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
 482                         break;
 483
 484                 case ICMP_UNREACH_PRECEDENCE_CUTOFF:
 485                         (void)snprintf(buf, sizeof(buf),
 486                             "host %s unreachable - precedence cutoff",
 487                             GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
 488                         break;
 489
 490                 default:
 491                         (void)snprintf(buf, sizeof(buf),
 492                             "%s unreachable - #%u",
 493                             GET_IPADDR_STRING(dp->icmp_ip.ip_dst),
 494                             icmp_code);
 495                         break;
 496                 }
 497                 break;
 498
 499         case ICMP_REDIRECT:
 500                 switch (icmp_code) {
 501
 502                 case ICMP_REDIRECT_NET:
 503                         (void)snprintf(buf, sizeof(buf),
 504                             "redirect %s to net %s",
 505                             GET_IPADDR_STRING(dp->icmp_ip.ip_dst),
 506                             GET_IPADDR_STRING(dp->icmp_gwaddr));
 507                         break;
 508
 509                 case ICMP_REDIRECT_HOST:
 510                         (void)snprintf(buf, sizeof(buf),
 511                             "redirect %s to host %s",
 512                             GET_IPADDR_STRING(dp->icmp_ip.ip_dst),
 513                             GET_IPADDR_STRING(dp->icmp_gwaddr));
 514                         break;
 515
 516                 case ICMP_REDIRECT_TOSNET:
 517                         (void)snprintf(buf, sizeof(buf),
 518                             "redirect-tos %s to net %s",
 519                             GET_IPADDR_STRING(dp->icmp_ip.ip_dst),
 520                             GET_IPADDR_STRING(dp->icmp_gwaddr));
 521                         break;
 522
 523                 case ICMP_REDIRECT_TOSHOST:
 524                         (void)snprintf(buf, sizeof(buf),
 525                             "redirect-tos %s to host %s",
 526                             GET_IPADDR_STRING(dp->icmp_ip.ip_dst),
 527                             GET_IPADDR_STRING(dp->icmp_gwaddr));
 528                         break;
 529
 530                 default:
 531                         (void)snprintf(buf, sizeof(buf),
 532                             "redirect-#%u %s to %s", icmp_code,
 533                             GET_IPADDR_STRING(dp->icmp_ip.ip_dst),
 534                             GET_IPADDR_STRING(dp->icmp_gwaddr));
 535                         break;
 536                 }
 537                 break;
 538
 539         case ICMP_ROUTERADVERT:
 540             {
 541                 const struct ih_rdiscovery *ihp;
 542                 const struct id_rdiscovery *idp;
 543                 u_int lifetime, num, size;
 544
 545                 (void)snprintf(buf, sizeof(buf), "router advertisement");
 546                 cp = buf + strlen(buf);
 547
 548                 ihp = (const struct ih_rdiscovery *)&dp->icmp_void;
 549                 ND_TCHECK_SIZE(ihp);
 550                 (void)strncpy(cp, " lifetime ", sizeof(buf) - (cp - buf));
 551                 cp = buf + strlen(buf);
 552                 lifetime = GET_BE_U_2(ihp->ird_lifetime);
 553                 if (lifetime < 60) {
 554                         (void)snprintf(cp, sizeof(buf) - (cp - buf), "%u",
 555                             lifetime);
 556                 } else if (lifetime < 60 * 60) {
 557                         (void)snprintf(cp, sizeof(buf) - (cp - buf), "%u:%02u",
 558                             lifetime / 60, lifetime % 60);
 559                 } else {
 560                         (void)snprintf(cp, sizeof(buf) - (cp - buf),
 561                             "%u:%02u:%02u",
 562                             lifetime / 3600,
 563                             (lifetime % 3600) / 60,
 564                             lifetime % 60);
 565                 }
 566                 cp = buf + strlen(buf);
 567
 568                 num = GET_U_1(ihp->ird_addrnum);
 569                 (void)snprintf(cp, sizeof(buf) - (cp - buf), " %u:", num);
 570                 cp = buf + strlen(buf);
 571
 572                 size = GET_U_1(ihp->ird_addrsiz);
 573                 if (size != 2) {
 574                         (void)snprintf(cp, sizeof(buf) - (cp - buf),
 575                             " [size %u]", size);
 576                         break;
 577                 }
 578                 idp = (const struct id_rdiscovery *)&dp->icmp_data;
 579                 while (num > 0) {
 580                         ND_TCHECK_SIZE(idp);
 581                         (void)snprintf(cp, sizeof(buf) - (cp - buf), " {%s %u}",
 582                             GET_IPADDR_STRING(idp->ird_addr),
 583                             GET_BE_U_4(idp->ird_pref));
 584                         cp = buf + strlen(buf);
 585                         ++idp;
 586                 num--;
 587                 }
 588             }
 589                 break;
 590
 591         case ICMP_TIMXCEED:
 592                 ND_TCHECK_4(dp->icmp_ip.ip_dst);
 593                 switch (icmp_code) {
 594
 595                 case ICMP_TIMXCEED_INTRANS:
 596                         str = "time exceeded in-transit";
 597                         break;
 598
 599                 case ICMP_TIMXCEED_REASS:
 600                         str = "ip reassembly time exceeded";
 601                         break;
 602
 603                 default:
 604                         (void)snprintf(buf, sizeof(buf), "time exceeded-#%u",
 605                             icmp_code);
 606                         break;
 607                 }
 608                 break;
 609
 610         case ICMP_PARAMPROB:
 611                 if (icmp_code)
 612                         (void)snprintf(buf, sizeof(buf),
 613                             "parameter problem - code %u", icmp_code);
 614                 else {
 615                         (void)snprintf(buf, sizeof(buf),
 616                             "parameter problem - octet %u",
 617                             GET_U_1(dp->icmp_pptr));
 618                 }
 619                 break;
 620
 621         case ICMP_MASKREPLY:
 622                 (void)snprintf(buf, sizeof(buf), "address mask is 0x%08x",
 623                     GET_BE_U_4(dp->icmp_mask));
 624                 break;
 625
 626         case ICMP_TSTAMP:
 627                 (void)snprintf(buf, sizeof(buf),
 628                     "time stamp query id %u seq %u",
 629                     GET_BE_U_2(dp->icmp_id),
 630                     GET_BE_U_2(dp->icmp_seq));
 631                 break;
 632
 633         case ICMP_TSTAMPREPLY:
 634                 ND_TCHECK_4(dp->icmp_ttime);
 635                 (void)snprintf(buf, sizeof(buf),
 636                     "time stamp reply id %u seq %u: org %s",
 637                                GET_BE_U_2(dp->icmp_id),
 638                                GET_BE_U_2(dp->icmp_seq),
 639                                icmp_tstamp_print(GET_BE_U_4(dp->icmp_otime)));
 640
 641                 (void)snprintf(buf+strlen(buf),sizeof(buf)-strlen(buf),", recv %s",
 642                          icmp_tstamp_print(GET_BE_U_4(dp->icmp_rtime)));
 643                 (void)snprintf(buf+strlen(buf),sizeof(buf)-strlen(buf),", xmit %s",
 644                          icmp_tstamp_print(GET_BE_U_4(dp->icmp_ttime)));
 645                 break;
 646
 647         default:
 648                 str = tok2str(icmp2str, "type-#%u", icmp_type);
 649                 break;
 650         }
 651         ND_PRINT("ICMP %s, length %u", str, plen);
 652         if (ndo->ndo_vflag && !fragmented) { /* don't attempt checksumming if this is a frag */
 653                 if (ND_TTEST_LEN(bp, plen)) {
 654                         uint16_t sum;
 655
 656                         vec[0].ptr = (const uint8_t *)(const void *)dp;
 657                         vec[0].len = plen;
 658                         sum = in_cksum(vec, 1);
 659                         if (sum != 0) {
 660                                 uint16_t icmp_sum = GET_BE_U_2(dp->icmp_cksum);
 661                                 ND_PRINT(" (wrong icmp cksum %x (->%x)!)",
 662                                              icmp_sum,
 663                                              in_cksum_shouldbe(icmp_sum, sum));
 664                         }
 665                 }
 666         }
 667
 668         /*
 669          * print the remnants of the IP packet.
 670          * save the snaplength as this may get overridden in the IP printer.
 671          */
 672         if (ndo->ndo_vflag >= 1 && ICMP_ERRTYPE(icmp_type)) {
 673                 const u_char *snapend_save;
 674
 675                 bp += 8;
 676                 ND_PRINT("\n\t");
 677                 ip = (const struct ip *)bp;
 678                 snapend_save = ndo->ndo_snapend;
 679                 /*
 680                  * Update the snapend because extensions (MPLS, ...) may be
 681                  * present after the IP packet. In this case the current
 682                  * (outer) packet's snapend is not what ip_print() needs to
 683                  * decode an IP packet nested in the middle of an ICMP payload.
 684                  *
 685                  * This prevents that, in ip_print(), for the nested IP packet,
 686                  * the remaining length < remaining caplen.
 687                  */
 688                 ndo->ndo_snapend = ND_MIN(bp + GET_BE_U_2(ip->ip_len),
 689                                           ndo->ndo_snapend);
 690                 ip_print(ndo, bp, GET_BE_U_2(ip->ip_len));
 691                 ndo->ndo_snapend = snapend_save;
 692         }
 693
 694         /* ndo_protocol reassignment after ip_print() call */
 695         ndo->ndo_protocol = "icmp";
 696
 697         /*
 698          * Attempt to decode multi-part message extensions (rfc4884) only for some ICMP types.
 699          */
 700         if (ndo->ndo_vflag >= 1 && plen > ICMP_EXTD_MINLEN && ICMP_MULTIPART_EXT_TYPE(icmp_type)) {
 701
 702             ND_TCHECK_SIZE(ext_dp);
 703
 704             /*
 705              * Check first if the multi-part extension header shows a non-zero length.
 706              * If the length field is not set then silently verify the checksum
 707              * to check if an extension header is present. This is expedient,
 708              * however not all implementations set the length field proper.
 709              */
 710             if (GET_U_1(ext_dp->icmp_length) == 0 &&
 711                 ND_TTEST_LEN(ext_dp->icmp_ext_version_res, plen - ICMP_EXTD_MINLEN)) {
 712                 vec[0].ptr = (const uint8_t *)(const void *)&ext_dp->icmp_ext_version_res;
 713                 vec[0].len = plen - ICMP_EXTD_MINLEN;
 714                 if (in_cksum(vec, 1)) {
 715                     return;
 716                 }
 717             }
 718
 719             ND_PRINT("\n\tICMP Multi-Part extension v%u",
 720                    ICMP_EXT_EXTRACT_VERSION(*(ext_dp->icmp_ext_version_res)));
 721
 722             /*
 723              * Sanity checking of the header.
 724              */
 725             if (ICMP_EXT_EXTRACT_VERSION(*(ext_dp->icmp_ext_version_res)) !=
 726                 ICMP_EXT_VERSION) {
 727                 ND_PRINT(" packet not supported");
 728                 return;
 729             }
 730
 731             hlen = plen - ICMP_EXTD_MINLEN;
 732             if (ND_TTEST_LEN(ext_dp->icmp_ext_version_res, hlen)) {
 733                 vec[0].ptr = (const uint8_t *)(const void *)&ext_dp->icmp_ext_version_res;
 734                 vec[0].len = hlen;
 735                 ND_PRINT(", checksum 0x%04x (%scorrect), length %u",
 736                        GET_BE_U_2(ext_dp->icmp_ext_checksum),
 737                        in_cksum(vec, 1) ? "in" : "",
 738                        hlen);
 739             }
 740
 741             hlen -= 4; /* subtract common header size */
 742             obj_tptr = (const uint8_t *)ext_dp->icmp_ext_data;
 743
 744             while (hlen > sizeof(struct icmp_multipart_ext_object_header_t)) {
 745
 746                 icmp_multipart_ext_object_header = (const struct icmp_multipart_ext_object_header_t *)obj_tptr;
 747                 ND_TCHECK_SIZE(icmp_multipart_ext_object_header);
 748                 obj_tlen = GET_BE_U_2(icmp_multipart_ext_object_header->length);
 749                 obj_class_num = GET_U_1(icmp_multipart_ext_object_header->class_num);
 750                 obj_ctype = GET_U_1(icmp_multipart_ext_object_header->ctype);
 751                 obj_tptr += sizeof(struct icmp_multipart_ext_object_header_t);
 752
 753                 ND_PRINT("\n\t  %s Object (%u), Class-Type: %u, length %u",
 754                        tok2str(icmp_multipart_ext_obj_values,"unknown",obj_class_num),
 755                        obj_class_num,
 756                        obj_ctype,
 757                        obj_tlen);
 758
 759                 hlen-=sizeof(struct icmp_multipart_ext_object_header_t); /* length field includes tlv header */
 760
 761                 /* infinite loop protection */
 762                 if ((obj_class_num == 0) ||
 763                     (obj_tlen < sizeof(struct icmp_multipart_ext_object_header_t))) {
 764                     return;
 765                 }
 766                 obj_tlen-=sizeof(struct icmp_multipart_ext_object_header_t);
 767
 768                 switch (obj_class_num) {
 769                 case MPLS_STACK_ENTRY_OBJECT_CLASS:
 770                     switch(obj_ctype) {
 771                     case 1:
 772                         raw_label = GET_BE_U_4(obj_tptr);
 773                         ND_PRINT("\n\t    label %u, tc %u", MPLS_LABEL(raw_label), MPLS_TC(raw_label));
 774                         if (MPLS_STACK(raw_label))
 775                             ND_PRINT(", [S]");
 776                         ND_PRINT(", ttl %u", MPLS_TTL(raw_label));
 777                         break;
 778                     default:
 779                         print_unknown_data(ndo, obj_tptr, "\n\t    ", obj_tlen);
 780                     }
 781                     break;
 782
 783                 default:
 784                     print_unknown_data(ndo, obj_tptr, "\n\t    ", obj_tlen);
 785                     break;
 786                 }
 787                 if (hlen < obj_tlen)
 788                     break;
 789                 hlen -= obj_tlen;
 790                 obj_tptr += obj_tlen;
 791             }
 792         }
 793
 794         return;
 795 trunc:
 796         nd_print_trunc(ndo);
 797 }