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