1/* 2 * Copyright (c) 1988, 1989, 1990, 1991, 1993, 1994, 1995, 1996 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that: (1) source code distributions 7 * retain the above copyright notice and this paragraph in its entirety, (2) 8 * distributions including binary code include the above copyright notice and 9 * this paragraph in its entirety in the documentation or other materials 10 * provided with the distribution, and (3) all advertising materials mentioning 11 * features or use of this software display the following acknowledgement: 12 * ``This product includes software developed by the University of California, 13 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of 14 * the University nor the names of its contributors may be used to endorse 15 * or promote products derived from this software without specific prior 16 * written permission. 17 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED 18 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF 19 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. 20 */ 21 22#ifndef lint 23static const char rcsid[] _U_ = 24 "@(#) $Header: /tcpdump/master/tcpdump/print-icmp.c,v 1.81.2.6 2007/09/13 17:40:18 guy Exp $ (LBL)"; 25#endif 26 27#ifdef HAVE_CONFIG_H 28#include "config.h" 29#endif 30 31#include <tcpdump-stdinc.h> 32 33#include <stdio.h> 34#include <string.h> 35 36#include "interface.h" 37#include "addrtoname.h" 38#include "extract.h" /* must come after interface.h */ 39 40#include "ip.h" 41#include "udp.h" 42#include "ipproto.h" 43#include "mpls.h" 44 45/* 46 * Interface Control Message Protocol Definitions. 47 * Per RFC 792, September 1981. 48 */ 49 50/* 51 * Structure of an icmp header. 52 */ 53struct icmp { 54 u_int8_t icmp_type; /* type of message, see below */ 55 u_int8_t icmp_code; /* type sub code */ 56 u_int16_t icmp_cksum; /* ones complement cksum of struct */ 57 union { 58 u_int8_t ih_pptr; /* ICMP_PARAMPROB */ 59 struct in_addr ih_gwaddr; /* ICMP_REDIRECT */ 60 struct ih_idseq { 61 u_int16_t icd_id; 62 u_int16_t icd_seq; 63 } ih_idseq; 64 u_int32_t ih_void; 65 } icmp_hun; 66#define icmp_pptr icmp_hun.ih_pptr 67#define icmp_gwaddr icmp_hun.ih_gwaddr 68#define icmp_id icmp_hun.ih_idseq.icd_id 69#define icmp_seq icmp_hun.ih_idseq.icd_seq 70#define icmp_void icmp_hun.ih_void 71 union { 72 struct id_ts { 73 u_int32_t its_otime; 74 u_int32_t its_rtime; 75 u_int32_t its_ttime; 76 } id_ts; 77 struct id_ip { 78 struct ip idi_ip; 79 /* options and then 64 bits of data */ 80 } id_ip; 81 u_int32_t id_mask; 82 u_int8_t id_data[1]; 83 } icmp_dun; 84#define icmp_otime icmp_dun.id_ts.its_otime 85#define icmp_rtime icmp_dun.id_ts.its_rtime 86#define icmp_ttime icmp_dun.id_ts.its_ttime 87#define icmp_ip icmp_dun.id_ip.idi_ip 88#define icmp_mask icmp_dun.id_mask 89#define icmp_data icmp_dun.id_data 90}; 91 92#define ICMP_MPLS_EXT_EXTRACT_VERSION(x) (((x)&0xf0)>>4) 93#define ICMP_MPLS_EXT_VERSION 2 94 95/* 96 * Lower bounds on packet lengths for various types. 97 * For the error advice packets must first insure that the 98 * packet is large enought to contain the returned ip header. 99 * Only then can we do the check to see if 64 bits of packet 100 * data have been returned, since we need to check the returned 101 * ip header length. 102 */ 103#define ICMP_MINLEN 8 /* abs minimum */ 104#define ICMP_EXTD_MINLEN (156 - sizeof (struct ip)) /* draft-bonica-internet-icmp-08 */ 105#define ICMP_TSLEN (8 + 3 * sizeof (u_int32_t)) /* timestamp */ 106#define ICMP_MASKLEN 12 /* address mask */ 107#define ICMP_ADVLENMIN (8 + sizeof (struct ip) + 8) /* min */ 108#define ICMP_ADVLEN(p) (8 + (IP_HL(&(p)->icmp_ip) << 2) + 8) 109 /* N.B.: must separately check that ip_hl >= 5 */ 110 111/* 112 * Definition of type and code field values. 113 */ 114#define ICMP_ECHOREPLY 0 /* echo reply */ 115#define ICMP_UNREACH 3 /* dest unreachable, codes: */ 116#define ICMP_UNREACH_NET 0 /* bad net */ 117#define ICMP_UNREACH_HOST 1 /* bad host */ 118#define ICMP_UNREACH_PROTOCOL 2 /* bad protocol */ 119#define ICMP_UNREACH_PORT 3 /* bad port */ 120#define ICMP_UNREACH_NEEDFRAG 4 /* IP_DF caused drop */ 121#define ICMP_UNREACH_SRCFAIL 5 /* src route failed */ 122#define ICMP_UNREACH_NET_UNKNOWN 6 /* unknown net */ 123#define ICMP_UNREACH_HOST_UNKNOWN 7 /* unknown host */ 124#define ICMP_UNREACH_ISOLATED 8 /* src host isolated */ 125#define ICMP_UNREACH_NET_PROHIB 9 /* prohibited access */ 126#define ICMP_UNREACH_HOST_PROHIB 10 /* ditto */ 127#define ICMP_UNREACH_TOSNET 11 /* bad tos for net */ 128#define ICMP_UNREACH_TOSHOST 12 /* bad tos for host */ 129#define ICMP_SOURCEQUENCH 4 /* packet lost, slow down */ 130#define ICMP_REDIRECT 5 /* shorter route, codes: */ 131#define ICMP_REDIRECT_NET 0 /* for network */ 132#define ICMP_REDIRECT_HOST 1 /* for host */ 133#define ICMP_REDIRECT_TOSNET 2 /* for tos and net */ 134#define ICMP_REDIRECT_TOSHOST 3 /* for tos and host */ 135#define ICMP_ECHO 8 /* echo service */ 136#define ICMP_ROUTERADVERT 9 /* router advertisement */ 137#define ICMP_ROUTERSOLICIT 10 /* router solicitation */ 138#define ICMP_TIMXCEED 11 /* time exceeded, code: */ 139#define ICMP_TIMXCEED_INTRANS 0 /* ttl==0 in transit */ 140#define ICMP_TIMXCEED_REASS 1 /* ttl==0 in reass */ 141#define ICMP_PARAMPROB 12 /* ip header bad */ 142#define ICMP_PARAMPROB_OPTABSENT 1 /* req. opt. absent */ 143#define ICMP_TSTAMP 13 /* timestamp request */ 144#define ICMP_TSTAMPREPLY 14 /* timestamp reply */ 145#define ICMP_IREQ 15 /* information request */ 146#define ICMP_IREQREPLY 16 /* information reply */ 147#define ICMP_MASKREQ 17 /* address mask request */ 148#define ICMP_MASKREPLY 18 /* address mask reply */ 149 150#define ICMP_MAXTYPE 18 151 152#define ICMP_INFOTYPE(type) \ 153 ((type) == ICMP_ECHOREPLY || (type) == ICMP_ECHO || \ 154 (type) == ICMP_ROUTERADVERT || (type) == ICMP_ROUTERSOLICIT || \ 155 (type) == ICMP_TSTAMP || (type) == ICMP_TSTAMPREPLY || \ 156 (type) == ICMP_IREQ || (type) == ICMP_IREQREPLY || \ 157 (type) == ICMP_MASKREQ || (type) == ICMP_MASKREPLY) 158#define ICMP_MPLS_EXT_TYPE(type) \ 159 ((type) == ICMP_UNREACH || \ 160 (type) == ICMP_TIMXCEED || \ 161 (type) == ICMP_PARAMPROB) 162/* rfc1700 */ 163#ifndef ICMP_UNREACH_NET_UNKNOWN 164#define ICMP_UNREACH_NET_UNKNOWN 6 /* destination net unknown */ 165#endif 166#ifndef ICMP_UNREACH_HOST_UNKNOWN 167#define ICMP_UNREACH_HOST_UNKNOWN 7 /* destination host unknown */ 168#endif 169#ifndef ICMP_UNREACH_ISOLATED 170#define ICMP_UNREACH_ISOLATED 8 /* source host isolated */ 171#endif 172#ifndef ICMP_UNREACH_NET_PROHIB 173#define ICMP_UNREACH_NET_PROHIB 9 /* admin prohibited net */ 174#endif 175#ifndef ICMP_UNREACH_HOST_PROHIB 176#define ICMP_UNREACH_HOST_PROHIB 10 /* admin prohibited host */ 177#endif 178#ifndef ICMP_UNREACH_TOSNET 179#define ICMP_UNREACH_TOSNET 11 /* tos prohibited net */ 180#endif 181#ifndef ICMP_UNREACH_TOSHOST 182#define ICMP_UNREACH_TOSHOST 12 /* tos prohibited host */ 183#endif 184 185/* rfc1716 */ 186#ifndef ICMP_UNREACH_FILTER_PROHIB 187#define ICMP_UNREACH_FILTER_PROHIB 13 /* admin prohibited filter */ 188#endif 189#ifndef ICMP_UNREACH_HOST_PRECEDENCE 190#define ICMP_UNREACH_HOST_PRECEDENCE 14 /* host precedence violation */ 191#endif 192#ifndef ICMP_UNREACH_PRECEDENCE_CUTOFF 193#define ICMP_UNREACH_PRECEDENCE_CUTOFF 15 /* precedence cutoff */ 194#endif 195 196/* Most of the icmp types */ 197static struct tok icmp2str[] = { 198 { ICMP_ECHOREPLY, "echo reply" }, 199 { ICMP_SOURCEQUENCH, "source quench" }, 200 { ICMP_ECHO, "echo request" }, 201 { ICMP_ROUTERSOLICIT, "router solicitation" }, 202 { ICMP_TSTAMP, "time stamp request" }, 203 { ICMP_TSTAMPREPLY, "time stamp reply" }, 204 { ICMP_IREQ, "information request" }, 205 { ICMP_IREQREPLY, "information reply" }, 206 { ICMP_MASKREQ, "address mask request" }, 207 { 0, NULL } 208}; 209 210/* Formats for most of the ICMP_UNREACH codes */ 211static struct tok unreach2str[] = { 212 { ICMP_UNREACH_NET, "net %s unreachable" }, 213 { ICMP_UNREACH_HOST, "host %s unreachable" }, 214 { ICMP_UNREACH_SRCFAIL, 215 "%s unreachable - source route failed" }, 216 { ICMP_UNREACH_NET_UNKNOWN, "net %s unreachable - unknown" }, 217 { ICMP_UNREACH_HOST_UNKNOWN, "host %s unreachable - unknown" }, 218 { ICMP_UNREACH_ISOLATED, 219 "%s unreachable - source host isolated" }, 220 { ICMP_UNREACH_NET_PROHIB, 221 "net %s unreachable - admin prohibited" }, 222 { ICMP_UNREACH_HOST_PROHIB, 223 "host %s unreachable - admin prohibited" }, 224 { ICMP_UNREACH_TOSNET, 225 "net %s unreachable - tos prohibited" }, 226 { ICMP_UNREACH_TOSHOST, 227 "host %s unreachable - tos prohibited" }, 228 { ICMP_UNREACH_FILTER_PROHIB, 229 "host %s unreachable - admin prohibited filter" }, 230 { ICMP_UNREACH_HOST_PRECEDENCE, 231 "host %s unreachable - host precedence violation" }, 232 { ICMP_UNREACH_PRECEDENCE_CUTOFF, 233 "host %s unreachable - precedence cutoff" }, 234 { 0, NULL } 235}; 236 237/* Formats for the ICMP_REDIRECT codes */ 238static struct tok type2str[] = { 239 { ICMP_REDIRECT_NET, "redirect %s to net %s" }, 240 { ICMP_REDIRECT_HOST, "redirect %s to host %s" }, 241 { ICMP_REDIRECT_TOSNET, "redirect-tos %s to net %s" }, 242 { ICMP_REDIRECT_TOSHOST, "redirect-tos %s to host %s" }, 243 { 0, NULL } 244}; 245 246/* rfc1191 */ 247struct mtu_discovery { 248 u_int16_t unused; 249 u_int16_t nexthopmtu; 250}; 251 252/* rfc1256 */ 253struct ih_rdiscovery { 254 u_int8_t ird_addrnum; 255 u_int8_t ird_addrsiz; 256 u_int16_t ird_lifetime; 257}; 258 259struct id_rdiscovery { 260 u_int32_t ird_addr; 261 u_int32_t ird_pref; 262}; 263 264/* 265 * draft-bonica-internet-icmp-08 266 * 267 * The Destination Unreachable, Time Exceeded 268 * and Parameter Problem messages are slighly changed as per 269 * the above draft. A new Length field gets added to give 270 * the caller an idea about the length of the piggypacked 271 * IP packet before the MPLS extension header starts. 272 * 273 * The Length field represents length of the padded "original datagram" 274 * field measured in 32-bit words. 275 * 276 * 0 1 2 3 277 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 278 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 279 * | Type | Code | Checksum | 280 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 281 * | unused | Length | unused | 282 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 283 * | Internet Header + leading octets of original datagram | 284 * | | 285 * | // | 286 * | | 287 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 288 */ 289 290struct icmp_ext_t { 291 u_int8_t icmp_type; 292 u_int8_t icmp_code; 293 u_int8_t icmp_checksum[2]; 294 u_int8_t icmp_reserved; 295 u_int8_t icmp_length; 296 u_int8_t icmp_reserved2[2]; 297 u_int8_t icmp_ext_legacy_header[128]; /* extension header starts 128 bytes after ICMP header */ 298 u_int8_t icmp_ext_version_res[2]; 299 u_int8_t icmp_ext_checksum[2]; 300 u_int8_t icmp_ext_data[1]; 301}; 302 303struct icmp_mpls_ext_object_header_t { 304 u_int8_t length[2]; 305 u_int8_t class_num; 306 u_int8_t ctype; 307}; 308 309static const struct tok icmp_mpls_ext_obj_values[] = { 310 { 1, "MPLS Stack Entry" }, 311 { 2, "Extended Payload" }, 312 { 0, NULL} 313}; 314 315/* prototypes */ 316const char *icmp_tstamp_print(u_int); 317 318/* print the milliseconds since midnight UTC */ 319const char * 320icmp_tstamp_print(u_int tstamp) { 321 u_int msec,sec,min,hrs; 322 323 static char buf[64]; 324 325 msec = tstamp % 1000; 326 sec = tstamp / 1000; 327 min = sec / 60; sec -= min * 60; 328 hrs = min / 60; min -= hrs * 60; 329 snprintf(buf, sizeof(buf), "%02u:%02u:%02u.%03u",hrs,min,sec,msec); 330 return buf; 331} 332 333void 334icmp_print(const u_char *bp, u_int plen, const u_char *bp2, int fragmented) 335{ 336 char *cp; 337 const struct icmp *dp; 338 const struct icmp_ext_t *ext_dp; 339 const struct ip *ip; 340 const char *str, *fmt; 341 const struct ip *oip; 342 const struct udphdr *ouh; 343 const u_int8_t *obj_tptr; 344 u_int32_t raw_label; 345 const u_char *snapend_save; 346 const struct icmp_mpls_ext_object_header_t *icmp_mpls_ext_object_header; 347 u_int hlen, dport, mtu, obj_tlen, obj_class_num, obj_ctype; 348 char buf[MAXHOSTNAMELEN + 100]; 349 350 dp = (struct icmp *)bp; 351 ext_dp = (struct icmp_ext_t *)bp; 352 ip = (struct ip *)bp2; 353 str = buf; 354 355 TCHECK(dp->icmp_code); 356 switch (dp->icmp_type) { 357 358 case ICMP_ECHO: 359 case ICMP_ECHOREPLY: 360 TCHECK(dp->icmp_seq); 361 (void)snprintf(buf, sizeof(buf), "echo %s, id %u, seq %u", 362 dp->icmp_type == ICMP_ECHO ? 363 "request" : "reply", 364 EXTRACT_16BITS(&dp->icmp_id), 365 EXTRACT_16BITS(&dp->icmp_seq)); 366 break; 367 368 case ICMP_UNREACH: 369 TCHECK(dp->icmp_ip.ip_dst); 370 switch (dp->icmp_code) { 371 372 case ICMP_UNREACH_PROTOCOL: 373 TCHECK(dp->icmp_ip.ip_p); 374 (void)snprintf(buf, sizeof(buf), 375 "%s protocol %d unreachable", 376 ipaddr_string(&dp->icmp_ip.ip_dst), 377 dp->icmp_ip.ip_p); 378 break; 379 380 case ICMP_UNREACH_PORT: 381 TCHECK(dp->icmp_ip.ip_p); 382 oip = &dp->icmp_ip; 383 hlen = IP_HL(oip) * 4; 384 ouh = (struct udphdr *)(((u_char *)oip) + hlen); 385 TCHECK(ouh->uh_dport); 386 dport = EXTRACT_16BITS(&ouh->uh_dport); 387 switch (oip->ip_p) { 388 389 case IPPROTO_TCP: 390 (void)snprintf(buf, sizeof(buf), 391 "%s tcp port %s unreachable", 392 ipaddr_string(&oip->ip_dst), 393 tcpport_string(dport)); 394 break; 395 396 case IPPROTO_UDP: 397 (void)snprintf(buf, sizeof(buf), 398 "%s udp port %s unreachable", 399 ipaddr_string(&oip->ip_dst), 400 udpport_string(dport)); 401 break; 402 403 default: 404 (void)snprintf(buf, sizeof(buf), 405 "%s protocol %d port %d unreachable", 406 ipaddr_string(&oip->ip_dst), 407 oip->ip_p, dport); 408 break; 409 } 410 break; 411 412 case ICMP_UNREACH_NEEDFRAG: 413 { 414 register const struct mtu_discovery *mp; 415 mp = (struct mtu_discovery *)&dp->icmp_void; 416 mtu = EXTRACT_16BITS(&mp->nexthopmtu); 417 if (mtu) { 418 (void)snprintf(buf, sizeof(buf), 419 "%s unreachable - need to frag (mtu %d)", 420 ipaddr_string(&dp->icmp_ip.ip_dst), mtu); 421 } else { 422 (void)snprintf(buf, sizeof(buf), 423 "%s unreachable - need to frag", 424 ipaddr_string(&dp->icmp_ip.ip_dst)); 425 } 426 } 427 break; 428 429 default: 430 fmt = tok2str(unreach2str, "#%d %%s unreachable", 431 dp->icmp_code); 432 (void)snprintf(buf, sizeof(buf), fmt, 433 ipaddr_string(&dp->icmp_ip.ip_dst)); 434 break; 435 } 436 break; 437 438 case ICMP_REDIRECT: 439 TCHECK(dp->icmp_ip.ip_dst); 440 fmt = tok2str(type2str, "redirect-#%d %%s to net %%s", 441 dp->icmp_code); 442 (void)snprintf(buf, sizeof(buf), fmt, 443 ipaddr_string(&dp->icmp_ip.ip_dst), 444 ipaddr_string(&dp->icmp_gwaddr)); 445 break; 446 447 case ICMP_ROUTERADVERT: 448 { 449 register const struct ih_rdiscovery *ihp; 450 register const struct id_rdiscovery *idp; 451 u_int lifetime, num, size; 452 453 (void)snprintf(buf, sizeof(buf), "router advertisement"); 454 cp = buf + strlen(buf); 455 456 ihp = (struct ih_rdiscovery *)&dp->icmp_void; 457 TCHECK(*ihp); 458 (void)strncpy(cp, " lifetime ", sizeof(buf) - (cp - buf)); 459 cp = buf + strlen(buf); 460 lifetime = EXTRACT_16BITS(&ihp->ird_lifetime); 461 if (lifetime < 60) { 462 (void)snprintf(cp, sizeof(buf) - (cp - buf), "%u", 463 lifetime); 464 } else if (lifetime < 60 * 60) { 465 (void)snprintf(cp, sizeof(buf) - (cp - buf), "%u:%02u", 466 lifetime / 60, lifetime % 60); 467 } else { 468 (void)snprintf(cp, sizeof(buf) - (cp - buf), 469 "%u:%02u:%02u", 470 lifetime / 3600, 471 (lifetime % 3600) / 60, 472 lifetime % 60); 473 } 474 cp = buf + strlen(buf); 475 476 num = ihp->ird_addrnum; 477 (void)snprintf(cp, sizeof(buf) - (cp - buf), " %d:", num); 478 cp = buf + strlen(buf); 479 480 size = ihp->ird_addrsiz; 481 if (size != 2) { 482 (void)snprintf(cp, sizeof(buf) - (cp - buf), 483 " [size %d]", size); 484 break; 485 } 486 idp = (struct id_rdiscovery *)&dp->icmp_data; 487 while (num-- > 0) { 488 TCHECK(*idp); 489 (void)snprintf(cp, sizeof(buf) - (cp - buf), " {%s %u}", 490 ipaddr_string(&idp->ird_addr), 491 EXTRACT_32BITS(&idp->ird_pref)); 492 cp = buf + strlen(buf); 493 ++idp; 494 } 495 } 496 break; 497 498 case ICMP_TIMXCEED: 499 TCHECK(dp->icmp_ip.ip_dst); 500 switch (dp->icmp_code) { 501 502 case ICMP_TIMXCEED_INTRANS: 503 str = "time exceeded in-transit"; 504 break; 505 506 case ICMP_TIMXCEED_REASS: 507 str = "ip reassembly time exceeded"; 508 break; 509 510 default: 511 (void)snprintf(buf, sizeof(buf), "time exceeded-#%d", 512 dp->icmp_code); 513 break; 514 } 515 break; 516 517 case ICMP_PARAMPROB: 518 if (dp->icmp_code) 519 (void)snprintf(buf, sizeof(buf), 520 "parameter problem - code %d", dp->icmp_code); 521 else { 522 TCHECK(dp->icmp_pptr); 523 (void)snprintf(buf, sizeof(buf), 524 "parameter problem - octet %d", dp->icmp_pptr); 525 } 526 break; 527 528 case ICMP_MASKREPLY: 529 TCHECK(dp->icmp_mask); 530 (void)snprintf(buf, sizeof(buf), "address mask is 0x%08x", 531 EXTRACT_32BITS(&dp->icmp_mask)); 532 break; 533 534 case ICMP_TSTAMP: 535 TCHECK(dp->icmp_seq); 536 (void)snprintf(buf, sizeof(buf), 537 "time stamp query id %u seq %u", 538 EXTRACT_16BITS(&dp->icmp_id), 539 EXTRACT_16BITS(&dp->icmp_seq)); 540 break; 541 542 case ICMP_TSTAMPREPLY: 543 TCHECK(dp->icmp_ttime); 544 (void)snprintf(buf, sizeof(buf), 545 "time stamp reply id %u seq %u: org %s", 546 EXTRACT_16BITS(&dp->icmp_id), 547 EXTRACT_16BITS(&dp->icmp_seq), 548 icmp_tstamp_print(EXTRACT_32BITS(&dp->icmp_otime))); 549 550 (void)snprintf(buf+strlen(buf),sizeof(buf)-strlen(buf),", recv %s", 551 icmp_tstamp_print(EXTRACT_32BITS(&dp->icmp_rtime))); 552 (void)snprintf(buf+strlen(buf),sizeof(buf)-strlen(buf),", xmit %s", 553 icmp_tstamp_print(EXTRACT_32BITS(&dp->icmp_ttime))); 554 break; 555 556 default: 557 str = tok2str(icmp2str, "type-#%d", dp->icmp_type); 558 break; 559 } 560 (void)printf("ICMP %s, length %u", str, plen); 561 if (vflag && !fragmented) { /* don't attempt checksumming if this is a frag */ 562 u_int16_t sum, icmp_sum; 563 if (TTEST2(*bp, plen)) { 564 sum = in_cksum((u_short*)dp, plen, 0); 565 if (sum != 0) { 566 icmp_sum = EXTRACT_16BITS(&dp->icmp_cksum); 567 (void)printf(" (wrong icmp cksum %x (->%x)!)", 568 icmp_sum, 569 in_cksum_shouldbe(icmp_sum, sum)); 570 } 571 } 572 } 573 574 /* 575 * print the remnants of the IP packet. 576 * save the snaplength as this may get overidden in the IP printer. 577 */ 578 if (vflag >= 1 && !ICMP_INFOTYPE(dp->icmp_type)) { 579 bp += 8; 580 (void)printf("\n\t"); 581 ip = (struct ip *)bp; 582 snaplen = snapend - bp; 583 snapend_save = snapend; 584 ip_print(gndo, bp, EXTRACT_16BITS(&ip->ip_len)); 585 snapend = snapend_save; 586 } 587 588 /* 589 * Attempt to decode the MPLS extensions only for some ICMP types. 590 */ 591 if (vflag >= 1 && plen > ICMP_EXTD_MINLEN && ICMP_MPLS_EXT_TYPE(dp->icmp_type)) { 592 593 TCHECK(*ext_dp); 594 595 /* 596 * Check first if the mpls extension header shows a non-zero length. 597 * If the length field is not set then silently verify the checksum 598 * to check if an extension header is present. This is expedient, 599 * however not all implementations set the length field proper. 600 */ 601 if (!ext_dp->icmp_length && 602 in_cksum((const u_short *)&ext_dp->icmp_ext_version_res, 603 plen - ICMP_EXTD_MINLEN, 0)) { 604 return; 605 } 606 607 printf("\n\tMPLS extension v%u", 608 ICMP_MPLS_EXT_EXTRACT_VERSION(*(ext_dp->icmp_ext_version_res))); 609 610 /* 611 * Sanity checking of the header. 612 */ 613 if (ICMP_MPLS_EXT_EXTRACT_VERSION(*(ext_dp->icmp_ext_version_res)) != 614 ICMP_MPLS_EXT_VERSION) { 615 printf(" packet not supported"); 616 return; 617 } 618 619 hlen = plen - ICMP_EXTD_MINLEN; 620 printf(", checksum 0x%04x (%scorrect), length %u", 621 EXTRACT_16BITS(ext_dp->icmp_ext_checksum), 622 in_cksum((const u_short *)&ext_dp->icmp_ext_version_res, 623 plen - ICMP_EXTD_MINLEN, 0) ? "in" : "", 624 hlen); 625 626 hlen -= 4; /* subtract common header size */ 627 obj_tptr = (u_int8_t *)ext_dp->icmp_ext_data; 628 629 while (hlen > sizeof(struct icmp_mpls_ext_object_header_t)) { 630 631 icmp_mpls_ext_object_header = (struct icmp_mpls_ext_object_header_t *)obj_tptr; 632 TCHECK(*icmp_mpls_ext_object_header); 633 obj_tlen = EXTRACT_16BITS(icmp_mpls_ext_object_header->length); 634 obj_class_num = icmp_mpls_ext_object_header->class_num; 635 obj_ctype = icmp_mpls_ext_object_header->ctype; 636 obj_tptr += sizeof(struct icmp_mpls_ext_object_header_t); 637 638 printf("\n\t %s Object (%u), Class-Type: %u, length %u", 639 tok2str(icmp_mpls_ext_obj_values,"unknown",obj_class_num), 640 obj_class_num, 641 obj_ctype, 642 obj_tlen); 643 644 hlen-=sizeof(struct icmp_mpls_ext_object_header_t); /* length field includes tlv header */ 645 646 /* infinite loop protection */ 647 if ((obj_class_num == 0) || 648 (obj_tlen < sizeof(struct icmp_mpls_ext_object_header_t))) { 649 return; 650 } 651 obj_tlen-=sizeof(struct icmp_mpls_ext_object_header_t); 652 653 switch (obj_class_num) { 654 case 1: 655 switch(obj_ctype) { 656 case 1: 657 TCHECK2(*obj_tptr, 4); 658 raw_label = EXTRACT_32BITS(obj_tptr); 659 printf("\n\t label %u, exp %u", MPLS_LABEL(raw_label), MPLS_EXP(raw_label)); 660 if (MPLS_STACK(raw_label)) 661 printf(", [S]"); 662 printf(", ttl %u", MPLS_TTL(raw_label)); 663 break; 664 default: 665 print_unknown_data(obj_tptr, "\n\t ", obj_tlen); 666 } 667 break; 668 669 /* 670 * FIXME those are the defined objects that lack a decoder 671 * you are welcome to contribute code ;-) 672 */ 673 case 2: 674 default: 675 print_unknown_data(obj_tptr, "\n\t ", obj_tlen); 676 break; 677 } 678 if (hlen < obj_tlen) 679 break; 680 hlen -= obj_tlen; 681 obj_tptr += obj_tlen; 682 } 683 } 684 685 return; 686trunc: 687 fputs("[|icmp]", stdout); 688} 689