epan/dissectors/packet-igmp.c

   1 /* packet-igmp.c   2001 Ronnie Sahlberg <See AUTHORS for email>
   2  * Routines for IGMP packet disassembly
   3  *
   4  * $Id$
   5  *
   6  * Wireshark - Network traffic analyzer
   7  * By Gerald Combs <gerald@wireshark.org>
   8  * Copyright 1998 Gerald Combs
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public License
  12  * as published by the Free Software Foundation; either version 2
  13  * of the License, or (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  23  */
  24 /*
  25         IGMP is defined in the following RFCs
  26         RFC988  Version 0       Obsolete
  27         RFC1054 Version 1
  28         RFC1112 Version 1       (same as RFC1054 as far as we are concerned)
  29         RFC2236 Version 2
  30         RFC3376 Version 3
  31
  32         Size in bytes for each packet
  33         type    RFC988  RFC1054 RFC2236 RFC3376  DVMRP  MRDISC  MSNIP  IGAP
  34                 v0      v1      v2      v3       v1/v3
  35         0x01      20
  36         0x02      20
  37         0x03      20
  38         0x04      20
  39         0x05      20
  40         0x06      20
  41         0x07      20
  42         0x08      20
  43         0x11               8*     8*     >=12
  44         0x12               8*     8*
  45         0x13                                     x
  46         0x16                      8
  47         0x17                      8
  48         0x22                            >=8
  49         0x23                                                    >=8b
  50         0x24                                            >=8a    8b
  51         0x25                                            4a      >=8b
  52         0x26                                            4a
  53         0x40                                                           ??c
  54         0x41                                                           ??c
  55         0x42                                                           ??c
  56
  57    * Differs in second byte of protocol. Always 0 in V1
  58
  59
  60         Multicast traceroute was taken from
  61         draft-ietf-idmr-traceroute-ipm-07.txt
  62
  63         Size in bytes for each packet
  64         type    draft-ietf-idmr-traceroute-ipm-07.ps
  65         0x1e      24 + n*32
  66         0x1f      24 + n*32 (n == 0 for Query)
  67
  68    x DVMRP Protocol  see packet-dvmrp.c
  69
  70         DVMRP is defined in the following RFCs
  71         RFC1075 Version 1
  72         draft-ietf-idmr-dvmrp-v3-10.txt Version 3
  73
  74         V1 and V3 can be distinguished by looking at bytes 6 and 7 in the
  75         IGMP header.
  76         If header[6]==0xff and header[7]==0x03 we have version 3.
  77
  78    a MRDISC Protocol  see packet-mrdisc.c
  79
  80         MRDISC : IGMP Multicast Router DISCovery
  81         draft-ietf-idmr-igmp-mrdisc-06.txt
  82         TTL == 1 and IP.DST==224.0.0.2 for all packets
  83
  84    b MSNIP Protocol  see packet-msnip.c
  85
  86         MSNIP : Multicast Source Notification of Interest Protocol
  87         draft-ietf-idmr-msnip-00.txt
  88         0x23, 0x24 are sent with ip.dst==224.0.0.22
  89         0x25 is sent as unicast.
  90
  91    c IGAP Protocol  see packet-igap.c
  92
  93         IGAP : Internet Group membership Authentication Protocol
  94         draft-hayashi-igap-03.txt
  95
  96 */
  97
  98 #ifdef HAVE_CONFIG_H
  99 # include "config.h"
 100 #endif
 101
 102 #include <stdio.h>
 103 #include <string.h>
 104 #include <glib.h>
 105
 106 #include <epan/packet.h>
 107 #include <epan/ipproto.h>
 108 #include <epan/in_cksum.h>
 109 #include "packet-igmp.h"
 110 #include "packet-dvmrp.h"
 111 #include "packet-pim.h"
 112 #include "packet-mrdisc.h"
 113 #include "packet-msnip.h"
 114 #include "packet-igap.h"
 115
 116 static int proto_igmp = -1;
 117 static int hf_type = -1;
 118 static int hf_version = -1;
 119 static int hf_group_type = -1;
 120 static int hf_reply_code = -1;
 121 static int hf_reply_pending = -1;
 122 static int hf_checksum = -1;
 123 static int hf_checksum_bad = -1;
 124 static int hf_identifier = -1;
 125 static int hf_access_key = -1;
 126 static int hf_max_resp = -1;
 127 static int hf_max_resp_exp = -1;
 128 static int hf_max_resp_mant = -1;
 129 static int hf_suppress = -1;
 130 static int hf_qrv = -1;
 131 static int hf_qqic = -1;
 132 static int hf_num_src = -1;
 133 static int hf_saddr = -1;
 134 static int hf_num_grp_recs = -1;
 135 static int hf_record_type = -1;
 136 static int hf_aux_data_len = -1;
 137 static int hf_maddr = -1;
 138 static int hf_aux_data = -1;
 139 static int hf_mtrace_max_hops = -1;
 140 static int hf_mtrace_saddr = -1;
 141 static int hf_mtrace_raddr = -1;
 142 static int hf_mtrace_rspaddr = -1;
 143 static int hf_mtrace_resp_ttl = -1;
 144 static int hf_mtrace_q_id = -1;
 145 static int hf_mtrace_q_arrival = -1;
 146 static int hf_mtrace_q_inaddr = -1;
 147 static int hf_mtrace_q_outaddr = -1;
 148 static int hf_mtrace_q_prevrtr = -1;
 149 static int hf_mtrace_q_inpkt = -1;
 150 static int hf_mtrace_q_outpkt = -1;
 151 static int hf_mtrace_q_total = -1;
 152 static int hf_mtrace_q_rtg_proto = -1;
 153 static int hf_mtrace_q_fwd_ttl = -1;
 154 static int hf_mtrace_q_mbz = -1;
 155 static int hf_mtrace_q_s = -1;
 156 static int hf_mtrace_q_src_mask = -1;
 157 static int hf_mtrace_q_fwd_code = -1;
 158
 159 static int ett_igmp = -1;
 160 static int ett_group_record = -1;
 161 static int ett_sqrv_bits = -1;
 162 static int ett_max_resp = -1;
 163 static int ett_mtrace_block = -1;
 164
 165 #define MC_ALL_ROUTERS          0xe0000002
 166 #define MC_ALL_IGMPV3_ROUTERS   0xe0000016
 167
 168
 169 #define IGMP_V0_CREATE_GROUP_REQUEST    0x01
 170 #define IGMP_V0_CREATE_GROUP_REPLY      0x02
 171 #define IGMP_V0_JOIN_GROUP_REQUEST      0x03
 172 #define IGMP_V0_JOIN_GROUP_REPLY        0x04
 173 #define IGMP_V0_LEAVE_GROUP_REQUEST     0x05
 174 #define IGMP_V0_LEAVE_GROUP_REPLY       0x06
 175 #define IGMP_V0_CONFIRM_GROUP_REQUEST   0x07
 176 #define IGMP_V0_CONFIRM_GROUP_REPLY     0x08
 177 #define IGMP_V1_HOST_MEMBERSHIP_QUERY   0x11
 178 #define IGMP_V1_HOST_MEMBERSHIP_REPORT  0x12
 179 #define IGMP_DVMRP                      0x13
 180 #define IGMP_V1_PIM_ROUTING_MESSAGE     0x14
 181 #define IGMP_V2_MEMBERSHIP_REPORT       0x16
 182 #define IGMP_V2_LEAVE_GROUP             0x17
 183 #define IGMP_TRACEROUTE_RESPONSE        0x1e
 184 #define IGMP_TRACEROUTE_QUERY_REQ       0x1f
 185 #define IGMP_V3_MEMBERSHIP_REPORT       0x22
 186 #define IGMP_TYPE_0x23                  0x23
 187 #define IGMP_TYPE_0x24                  0x24
 188 #define IGMP_TYPE_0x25                  0x25
 189 #define IGMP_TYPE_0x26                  0x26
 190
 191 #define IGMP_TRACEROUTE_HDR_LEN           24
 192 #define IGMP_TRACEROUTE_RSP_LEN           32
 193
 194 static const value_string commands[] = {
 195         {IGMP_V0_CREATE_GROUP_REQUEST,  "Create Group Request"          },
 196         {IGMP_V0_CREATE_GROUP_REPLY,    "Create Group Reply"            },
 197         {IGMP_V0_JOIN_GROUP_REQUEST,    "Join Group Request"            },
 198         {IGMP_V0_JOIN_GROUP_REPLY,      "Join Group Reply"              },
 199         {IGMP_V0_LEAVE_GROUP_REQUEST,   "Leave Group Request"           },
 200         {IGMP_V0_LEAVE_GROUP_REPLY,     "Leave Group Reply"             },
 201         {IGMP_V0_CONFIRM_GROUP_REQUEST, "Confirm Group Request"         },
 202         {IGMP_V0_CONFIRM_GROUP_REPLY,   "Confirm Group Reply"           },
 203         {IGMP_V1_HOST_MEMBERSHIP_QUERY, "Membership Query"              },
 204         {IGMP_V1_HOST_MEMBERSHIP_REPORT,"Membership Report"             },
 205         {IGMP_DVMRP,                    "DVMRP Protocol"                },
 206         {IGMP_V1_PIM_ROUTING_MESSAGE,   "PIM Routing Message"           },
 207         {IGMP_V2_MEMBERSHIP_REPORT,     "Membership Report"             },
 208         {IGMP_V2_LEAVE_GROUP,           "Leave Group"                   },
 209         {IGMP_TRACEROUTE_RESPONSE,      "Traceroute Response"           },
 210         {IGMP_TRACEROUTE_QUERY_REQ,     "Traceroute Query or Request"   },
 211         {IGMP_V3_MEMBERSHIP_REPORT,     "Membership Report"             },
 212         {0,             NULL}
 213 };
 214
 215 #define IGMP_V3_S               0x08
 216 #define IGMP_V3_QRV_MASK        0x07
 217
 218 #define IGMP_MAX_RESP_EXP       0x70
 219 #define IGMP_MAX_RESP_MANT      0x0f
 220
 221 #define IGMP_V0_GROUP_PUBLIC    0x00
 222 #define IGMP_V0_GROUP_PRIVATE   0x01
 223
 224 static const value_string vs_group_type[] = {
 225         {IGMP_V0_GROUP_PUBLIC,          "Public Group"                  },
 226         {IGMP_V0_GROUP_PRIVATE,         "Private Group"                 },
 227         {0,             NULL}
 228 };
 229
 230 #define IGMP_V0_REPLY_GRANTED   0x00
 231 #define IGMP_V0_REPLY_NO_RESOURCES      0x01
 232 #define IGMP_V0_REPLY_INVALID_CODE      0x02
 233 #define IGMP_V0_REPLY_INVALID_GROUP     0x03
 234 #define IGMP_V0_REPLY_INVALID_KEY       0x04
 235
 236 static const value_string vs_reply_code[] = {
 237         {IGMP_V0_REPLY_GRANTED, "Request Granted"       },
 238         {IGMP_V0_REPLY_NO_RESOURCES,    "Request Denied, No Resources"  },
 239         {IGMP_V0_REPLY_INVALID_CODE,    "Request Denied, Invalid Code"  },
 240         {IGMP_V0_REPLY_INVALID_GROUP,   "Request Denied, Invalid Group" },
 241         {IGMP_V0_REPLY_INVALID_KEY,     "Request Denied, Invalid Key"   },
 242         {0,             NULL}
 243 };
 244
 245 static const true_false_string tfs_s = {
 246         "SUPPRESS router side processing",
 247         "Do not suppress router side processing"
 248 };
 249
 250 #define IGMP_V3_MODE_IS_INCLUDE         1
 251 #define IGMP_V3_MODE_IS_EXCLUDE         2
 252 #define IGMP_V3_CHANGE_TO_INCLUDE_MODE  3
 253 #define IGMP_V3_CHANGE_TO_EXCLUDE_MODE  4
 254 #define IGMP_V3_ALLOW_NEW_SOURCES       5
 255 #define IGMP_V3_BLOCK_OLD_SOURCES       6
 256
 257 static const value_string vs_record_type[] = {
 258         {IGMP_V3_MODE_IS_INCLUDE,       "Mode Is Include"               },
 259         {IGMP_V3_MODE_IS_EXCLUDE,       "Mode Is Exclude"               },
 260         {IGMP_V3_CHANGE_TO_INCLUDE_MODE,"Change To Include Mode"        },
 261         {IGMP_V3_CHANGE_TO_EXCLUDE_MODE,"Change To Exclude Mode"        },
 262         {IGMP_V3_ALLOW_NEW_SOURCES,     "Allow New Sources"             },
 263         {IGMP_V3_BLOCK_OLD_SOURCES,     "Block Old Sources"             },
 264         { 0,    NULL}
 265 };
 266
 267 static const value_string mtrace_rtg_vals[] = {
 268         {1,  "DVMRP"                                        },
 269         {2,  "MOSPF"                                        },
 270         {3,  "PIM"                                          },
 271         {4,  "CBT"                                          },
 272         {5,  "PIM using special routing table"              },
 273         {6,  "PIM using a static route"                     },
 274         {7,  "DVMRP using a static route"                   },
 275         {8,  "PIM using MBGP (aka BGP4+) route"             },
 276         {9,  "CBT using special routing table"              },
 277         {10, "CBT using a static route"                     },
 278         {11, "PIM using state created by Assert processing" },
 279         {0,  NULL}
 280 };
 281
 282 static const value_string mtrace_fwd_code_vals[] = {
 283         {0x00, "NO_ERROR"       },
 284         {0x01, "WRONG_IF"       },
 285         {0x02, "PRUNE_SENT"     },
 286         {0x03, "PRUNE_RCVD"     },
 287         {0x04, "SCOPED"         },
 288         {0x05, "NO_ROUTE"       },
 289         {0x06, "WRONG_LAST_HOP" },
 290         {0x07, "NOT_FORWARDING" },
 291         {0x08, "REACHED_RP"     },
 292         {0x09, "RPF_IF"         },
 293         {0x0A, "NO_MULTICAST"   },
 294         {0x0B, "INFO_HIDDEN"    },
 295         {0x81, "NO_SPACE"       },
 296         {0x82, "OLD_ROUTER"     },
 297         {0x83, "ADMIN_PROHIB"   },
 298         {0, NULL}
 299 };
 300
 301 #define PRINT_IGMP_VERSION(version)                                     \
 302         if (check_col(pinfo->cinfo, COL_INFO)) {                        \
 303                 col_add_fstr(pinfo->cinfo, COL_INFO,                    \
 304                         "V%d %s",version,val_to_str(type, commands,     \
 305                                 "Unknown Type:0x%02x"));                \
 306         }                                                               \
 307         /* version of IGMP protocol */                                  \
 308         proto_tree_add_uint(tree, hf_version, tvb, 0, 0, version);      \
 309         /* type of command */                                           \
 310         proto_tree_add_uint(tree, hf_type, tvb, offset, 1, type);       \
 311         offset += 1;
 312
 313 void igmp_checksum(proto_tree *tree, tvbuff_t *tvb, int hf_index,
 314     int hf_index_bad, packet_info *pinfo, guint len)
 315 {
 316         guint16 cksum, hdrcksum;
 317         vec_t cksum_vec[1];
 318
 319         if (len == 0) {
 320                 /*
 321                  * Checksum the entire IGMP packet.
 322                  */
 323                 len = tvb_reported_length(tvb);
 324         }
 325
 326         hdrcksum = tvb_get_ntohs(tvb, 2);
 327         if (!pinfo->fragmented && tvb_length(tvb) >= len) {
 328                 /*
 329                  * The packet isn't part of a fragmented datagram and isn't
 330                  * truncated, so we can checksum it.
 331                  */
 332                 cksum_vec[0].ptr = tvb_get_ptr(tvb, 0, len);
 333                 cksum_vec[0].len = len;
 334
 335                 cksum = in_cksum(&cksum_vec[0],1);
 336
 337                 if (cksum == 0) {
 338                         proto_tree_add_uint_format(tree, hf_index,
 339                             tvb, 2, 2, hdrcksum,
 340                             "Header checksum: 0x%04x [correct]", hdrcksum);
 341                 } else {
 342                         proto_tree_add_boolean_hidden(tree, hf_index_bad,
 343                             tvb, 2, 2, TRUE);
 344                         proto_tree_add_uint_format(tree, hf_index,
 345                             tvb, 2, 2, hdrcksum,
 346                             "Header checksum: 0x%04x [incorrect, should be 0x%04x]", hdrcksum,in_cksum_shouldbe(hdrcksum,cksum));
 347                 }
 348         } else
 349                 proto_tree_add_uint(tree, hf_index, tvb, 2, 2, hdrcksum);
 350
 351         return;
 352 }
 353
 354
 355 /* Unknown IGMP message type */
 356 static int
 357 dissect_igmp_unknown(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, int type, int offset)
 358 {
 359         int len;
 360
 361         if (check_col(pinfo->cinfo, COL_INFO)) {
 362                 col_add_str(pinfo->cinfo, COL_INFO,
 363                         val_to_str(type, commands, "Unknown Type:0x%02x"));
 364         }
 365
 366         /* type of command */
 367         proto_tree_add_uint(tree, hf_type, tvb, offset, 1, type);
 368         offset += 1;
 369
 370         /* Just call the rest of it "data" */
 371         len = tvb_length_remaining(tvb, offset);
 372         proto_tree_add_text(tree, tvb, offset, len, "Data");
 373         offset += len;
 374
 375         return offset;
 376 }
 377
 378
 379
 380 /*************************************************************
 381  * IGMP Protocol dissectors
 382  *************************************************************/
 383 static int
 384 dissect_v3_max_resp(tvbuff_t *tvb, proto_tree *parent_tree, int offset)
 385 {
 386         proto_tree *tree;
 387         proto_item *item;
 388         guint8 bits;
 389         guint32 tsecs;
 390
 391         bits = tvb_get_guint8(tvb, offset);
 392         if (bits&0x80) {
 393                 tsecs = ((bits&IGMP_MAX_RESP_MANT)|0x10);
 394                 tsecs = tsecs << ( ((bits&IGMP_MAX_RESP_EXP)>>4) + 3);
 395         } else {
 396                 tsecs = bits;
 397         }
 398
 399         item = proto_tree_add_uint_format(parent_tree, hf_max_resp, tvb,
 400                         offset, 1, tsecs, "Max Response Time: %.1f sec (0x%02x)",tsecs*0.1,bits);
 401
 402         if (bits&0x80) {
 403                 tree = proto_item_add_subtree(item, ett_max_resp);
 404
 405                 proto_tree_add_uint(tree, hf_max_resp_exp, tvb, offset, 1,
 406                         bits);
 407                 proto_tree_add_uint(tree, hf_max_resp_mant, tvb, offset, 1,
 408                         bits);
 409         }
 410
 411         offset += 1;
 412
 413         return offset;
 414 }
 415
 416 static int
 417 dissect_v3_sqrv_bits(tvbuff_t *tvb, proto_tree *parent_tree, int offset)
 418 {
 419         proto_tree *tree;
 420         proto_item *item;
 421         guint8 bits;
 422
 423         bits = tvb_get_guint8(tvb, offset);
 424
 425         item = proto_tree_add_text(parent_tree, tvb, offset, 1,
 426                 "QRV=%d S=%s", bits&IGMP_V3_QRV_MASK,
 427                         (bits&IGMP_V3_S)?tfs_s.true_string:tfs_s.false_string);
 428         tree = proto_item_add_subtree(item, ett_sqrv_bits);
 429
 430         /* S flag */
 431         proto_tree_add_boolean(tree, hf_suppress, tvb, offset, 1, bits);
 432         /* QRV */
 433         proto_tree_add_uint(tree, hf_qrv, tvb, offset, 1, bits);
 434         offset += 1;
 435
 436         return offset;
 437 }
 438
 439 static int
 440 dissect_v3_group_record(tvbuff_t *tvb, proto_tree *parent_tree, int offset)
 441 {
 442         proto_tree *tree;
 443         proto_item *item;
 444         int old_offset = offset;
 445         guint8  adl;
 446         guint16 num;
 447         guint32 ip;
 448
 449         ip = tvb_get_ipv4(tvb, offset+4);
 450         item = proto_tree_add_text(parent_tree, tvb, offset, -1,
 451                 "Group Record : %s  %s",
 452                         ip_to_str((guint8*)&ip),
 453                         val_to_str(tvb_get_guint8(tvb, offset), vs_record_type,"")
 454                 );
 455         tree = proto_item_add_subtree(item, ett_group_record);
 456
 457         /* record type */
 458         proto_tree_add_item(tree, hf_record_type, tvb, offset, 1, FALSE);
 459         offset += 1;
 460
 461         /* aux data len */
 462         adl = tvb_get_guint8(tvb, offset);
 463         proto_tree_add_uint(tree, hf_aux_data_len, tvb, offset, 1, adl);
 464         offset += 1;
 465
 466         /*number of sources*/
 467         num = tvb_get_ntohs(tvb, offset);
 468         proto_tree_add_uint(tree, hf_num_src, tvb, offset, 2, num);
 469         offset += 2;
 470
 471         /* multicast address */
 472         proto_tree_add_item(tree, hf_maddr, tvb, offset, 4, FALSE);
 473         offset += 4;
 474
 475         /* source addresses */
 476         while(num--){
 477                 proto_tree_add_item(tree, hf_saddr, tvb, offset, 4, FALSE);
 478                 offset += 4;
 479         }
 480
 481         /* aux data */
 482         if(adl){
 483                 proto_tree_add_item(tree, hf_aux_data, tvb, offset, adl*4,
 484                     FALSE);
 485                 offset += adl*4;
 486         }
 487
 488         proto_item_set_len(item, offset-old_offset);
 489         return offset;
 490 }
 491
 492 /* dissectors for version 3, rfc???? */
 493 static int
 494 dissect_igmp_v3_response(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, int type, int offset)
 495 {
 496         guint16 num;
 497
 498         PRINT_IGMP_VERSION(3);
 499
 500         /* skip reserved field*/
 501         offset += 1;
 502
 503         /* checksum */
 504         igmp_checksum(tree, tvb, hf_checksum, hf_checksum_bad, pinfo, 0);
 505         offset += 2;
 506
 507         /* skip reserved field */
 508         offset += 2;
 509
 510         /* number of group records */
 511         num = tvb_get_ntohs(tvb, offset);
 512         proto_tree_add_uint(tree, hf_num_grp_recs, tvb, offset, 2, num);
 513         offset += 2;
 514
 515         while (num--) {
 516                 offset = dissect_v3_group_record(tvb, tree, offset);
 517         }
 518
 519         return offset;
 520 }
 521
 522 static int
 523 dissect_igmp_v3_query(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, int type, int offset)
 524 {
 525         guint16 num;
 526
 527         PRINT_IGMP_VERSION(3);
 528
 529         num = tvb_get_ntohs(tvb, offset+9);
 530         /* max resp code */
 531         offset = dissect_v3_max_resp(tvb, tree, offset);
 532
 533         /* checksum */
 534         igmp_checksum(tree, tvb, hf_checksum, hf_checksum_bad, pinfo, 0);
 535         offset += 2;
 536
 537         /* group address */
 538         proto_tree_add_item(tree, hf_maddr, tvb, offset, 4, FALSE);
 539         offset +=4;
 540
 541         /* bitmask for S and QRV */
 542         offset = dissect_v3_sqrv_bits(tvb, tree, offset);
 543
 544         /* qqic */
 545         proto_tree_add_item(tree, hf_qqic, tvb, offset, 1, FALSE);
 546         offset += 1;
 547
 548         /*number of sources*/
 549         proto_tree_add_uint(tree, hf_num_src, tvb, offset, 2, num);
 550         offset += 2;
 551
 552         while(num--){
 553                 proto_tree_add_item(tree, hf_saddr, tvb, offset, 4, FALSE);
 554                 offset += 4;
 555         }
 556
 557         return offset;
 558 }
 559
 560 /* dissector for version 2, rfc2236 */
 561 static int
 562 dissect_igmp_v2(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, int type, int offset)
 563 {
 564         guint8 tsecs;
 565
 566         PRINT_IGMP_VERSION(2);
 567
 568         /* max resp time */
 569         tsecs = tvb_get_guint8(tvb, offset);
 570         proto_tree_add_uint_format(tree, hf_max_resp, tvb,
 571                 offset, 1, tsecs, "Max Response Time: %.1f sec (0x%02x)", tsecs*0.1,tsecs);
 572         offset += 1;
 573
 574         /* checksum */
 575         igmp_checksum(tree, tvb, hf_checksum, hf_checksum_bad, pinfo, 8);
 576         offset += 2;
 577
 578         /* group address */
 579         proto_tree_add_item(tree, hf_maddr, tvb, offset, 4, FALSE);
 580         offset +=4;
 581
 582         return offset;
 583 }
 584
 585 /* dissector for version 1, rfc1054 */
 586 static int
 587 dissect_igmp_v1(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, int type, int offset)
 588 {
 589         PRINT_IGMP_VERSION(1);
 590
 591         /* skip unused byte */
 592         offset += 1;
 593
 594         /* checksum */
 595         igmp_checksum(tree, tvb, hf_checksum, hf_checksum_bad, pinfo, 8);
 596         offset += 2;
 597
 598         /* group address */
 599         proto_tree_add_item(tree, hf_maddr, tvb, offset, 4, FALSE);
 600         offset +=4;
 601
 602         return offset;
 603 }
 604
 605 /* dissector for version 0, rfc988 */
 606 static int
 607 dissect_igmp_v0(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, int type, int offset)
 608 {
 609         unsigned char code;
 610
 611         PRINT_IGMP_VERSION(0);
 612
 613         /* Code */
 614         code = tvb_get_guint8(tvb, offset);
 615         if (type==IGMP_V0_CREATE_GROUP_REQUEST) {
 616                 proto_tree_add_uint(tree, hf_group_type, tvb, offset, 1, code);
 617         } else if (!(type&0x01)) {
 618                 if (code <5) {
 619                         proto_tree_add_uint(tree, hf_reply_code, tvb, offset, 1, code);
 620                 } else {
 621                         proto_tree_add_uint(tree, hf_reply_pending, tvb, offset, 1, code);
 622                 }
 623         }
 624         offset += 1;
 625
 626         /* checksum */
 627         igmp_checksum(tree, tvb, hf_checksum, hf_checksum_bad, pinfo, 20);
 628         offset += 2;
 629
 630         /* identifier */
 631         proto_tree_add_item(tree, hf_identifier, tvb, offset, 4, FALSE);
 632         offset += 4;
 633
 634         /* group address */
 635         proto_tree_add_item(tree, hf_maddr, tvb, offset, 4, FALSE);
 636         offset +=4;
 637
 638         /* access key */
 639         proto_tree_add_item(tree, hf_access_key, tvb, offset, 8, FALSE);
 640         offset +=8;
 641
 642         return offset;
 643 }
 644
 645 /* dissector for multicast traceroute, rfc???? */
 646 static int
 647 dissect_igmp_mtrace(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, int type, int offset)
 648 {
 649         const char *typestr, *blocks = NULL;
 650         char buf[20];
 651
 652         /* All multicast traceroute packets (Query, Request and
 653          * Response) have the same fixed header. Request and Response
 654          * have one or more response data blocks following this fixed
 655          * header. Since Query and Request share the same IGMP type,
 656          * the method to differentiate between them is to check the
 657          * IGMP packet length. Queries are only
 658          * IGMP_TRACEROUTE_HDR_LEN bytes long.
 659          */
 660         if (type == IGMP_TRACEROUTE_RESPONSE) {
 661                 int i = (tvb_reported_length_remaining(tvb, offset) - IGMP_TRACEROUTE_HDR_LEN) / IGMP_TRACEROUTE_RSP_LEN;
 662                 g_snprintf(buf, sizeof buf, ", %d block%s", i, plurality(i, "", "s"));
 663                 typestr = "Traceroute Response";
 664                 blocks = buf;
 665         } else if (tvb_reported_length_remaining(tvb, offset) == IGMP_TRACEROUTE_HDR_LEN)
 666                 typestr = "Traceroute Query";
 667         else
 668                 typestr = "Traceroute Request";
 669
 670         if (check_col(pinfo->cinfo, COL_INFO)) {
 671                 col_set_str(pinfo->cinfo, COL_INFO, typestr);
 672                 if (blocks) col_append_str(pinfo->cinfo, COL_INFO, blocks);
 673         }
 674
 675         proto_tree_add_uint_format(tree, hf_type, tvb, offset, 1, type,
 676             "Type: %s (0x%02x)", typestr, type);
 677         offset += 1;
 678
 679         /* maximum number of hops that the requester wants to trace */
 680         proto_tree_add_item(tree, hf_mtrace_max_hops, tvb, offset, 1, FALSE);
 681         offset += 1;
 682
 683         /* checksum */
 684         igmp_checksum(tree, tvb, hf_checksum, hf_checksum_bad, pinfo, 0);
 685         offset += 2;
 686
 687         /* group address to be traced */
 688         proto_tree_add_item(tree, hf_maddr, tvb, offset, 4, FALSE);
 689         offset += 4;
 690
 691         /* address of multicast source for the path being traced */
 692         proto_tree_add_item(tree, hf_mtrace_saddr, tvb, offset, 4, FALSE);
 693         offset += 4;
 694
 695         /* address of multicast receiver for the path being traced */
 696         proto_tree_add_item(tree, hf_mtrace_raddr, tvb, offset, 4, FALSE);
 697         offset += 4;
 698
 699         /* address where the completed traceroute response packet gets sent */
 700         proto_tree_add_item(tree, hf_mtrace_rspaddr, tvb, offset, 4, FALSE);
 701         offset += 4;
 702
 703         /* for multicasted responses, TTL at which to multicast the response */
 704         proto_tree_add_item(tree, hf_mtrace_resp_ttl, tvb, offset, 1, FALSE);
 705         offset += 1;
 706
 707         /* unique identifier for this traceroute request (for e.g. duplicate/delay detection) */
 708         proto_tree_add_item(tree, hf_mtrace_q_id, tvb, offset, 3, FALSE);
 709         offset += 3;
 710
 711         /* If this was Query, we only had the fixed header */
 712         if (tvb_reported_length_remaining(tvb, offset) == 0)
 713                 return offset;
 714
 715         /* Loop through the response data blocks */
 716         while (tvb_reported_length_remaining(tvb, offset) >= IGMP_TRACEROUTE_RSP_LEN) {
 717                 proto_item *bi;
 718                 proto_tree *block_tree;
 719
 720                 bi = proto_tree_add_text(tree, tvb, offset, IGMP_TRACEROUTE_RSP_LEN,
 721                                          "Response data block: %s -> %s,  Proto: %s,  Forwarding Code: %s",
 722                                          ip_to_str(tvb_get_ptr(tvb, offset + 4, 4)),
 723                                          ip_to_str(tvb_get_ptr(tvb, offset + 8, 4)),
 724                                          val_to_str(tvb_get_guint8(tvb, offset + 28), mtrace_rtg_vals, "Unknown"),
 725                                          val_to_str(tvb_get_guint8(tvb, offset + 31), mtrace_fwd_code_vals, "Unknown"));
 726                 block_tree = proto_item_add_subtree(bi, ett_mtrace_block);
 727
 728                 /* Query Arrival Time */
 729                 proto_tree_add_item(block_tree, hf_mtrace_q_arrival, tvb, offset, 4, FALSE);
 730                 offset += 4;
 731
 732                 /* Incoming Interface Address */
 733                 proto_tree_add_item(block_tree, hf_mtrace_q_inaddr, tvb, offset, 4, FALSE);
 734                 offset += 4;
 735
 736                 /* Outgoing Interface Address */
 737                 proto_tree_add_item(block_tree, hf_mtrace_q_outaddr, tvb, offset, 4, FALSE);
 738                 offset += 4;
 739
 740                 /* Previous-Hop Router Address */
 741                 proto_tree_add_item(block_tree, hf_mtrace_q_prevrtr, tvb, offset, 4, FALSE);
 742                 offset += 4;
 743
 744                 /* Input packet count on incoming interface */
 745                 proto_tree_add_item(block_tree, hf_mtrace_q_inpkt, tvb, offset, 4, FALSE);
 746                 offset += 4;
 747
 748                 /* Output packet count on outgoing interface */
 749                 proto_tree_add_item(block_tree, hf_mtrace_q_outpkt, tvb, offset, 4, FALSE);
 750                 offset += 4;
 751
 752                 /* Total number of packets for this source-group pair */
 753                 proto_tree_add_item(block_tree, hf_mtrace_q_total, tvb, offset, 4, FALSE);
 754                 offset += 4;
 755
 756                 /* Routing protocol in use between this and previous-hop router */
 757                 proto_tree_add_item(block_tree, hf_mtrace_q_rtg_proto, tvb, offset, 1, FALSE);
 758                 offset += 1;
 759
 760                 /* TTL that a packet is required to be forwarded */
 761                 proto_tree_add_item(block_tree, hf_mtrace_q_fwd_ttl, tvb, offset, 1, FALSE);
 762                 offset += 1;
 763
 764                 /* Must be zeroed and ignored bit, S bit and src network mask length */
 765                 proto_tree_add_item(block_tree, hf_mtrace_q_mbz, tvb, offset, 1, FALSE);
 766                 proto_tree_add_item(block_tree, hf_mtrace_q_s, tvb, offset, 1, FALSE);
 767                 proto_tree_add_item(block_tree, hf_mtrace_q_src_mask, tvb, offset, 1, FALSE);
 768                 offset += 1;
 769
 770                 /* Forwarding information/error code */
 771                 proto_tree_add_item(block_tree, hf_mtrace_q_fwd_code, tvb, offset, 1, FALSE);
 772                 offset += 1;
 773         }
 774
 775
 776         return offset;
 777 }
 778
 779 static void
 780 dissect_igmp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree)
 781 {
 782         proto_tree *tree;
 783         proto_item *item;
 784         int offset = 0;
 785         unsigned char type;
 786         guint32 dst;
 787
 788         item = proto_tree_add_item(parent_tree, proto_igmp, tvb, offset, -1, FALSE);
 789         tree = proto_item_add_subtree(item, ett_igmp);
 790
 791
 792         if (check_col(pinfo->cinfo, COL_PROTOCOL)) {
 793                 col_set_str(pinfo->cinfo, COL_PROTOCOL, "IGMP");
 794         }
 795         if (check_col(pinfo->cinfo, COL_INFO)) {
 796                 col_clear(pinfo->cinfo, COL_INFO);
 797         }
 798
 799
 800         type = tvb_get_guint8(tvb, offset);
 801
 802
 803         /* version 0 */
 804         if ((type&0xf0)==0){
 805                 offset = dissect_igmp_v0(tvb, pinfo, tree, type, offset);
 806         }
 807
 808
 809         switch (type) {
 810
 811         case IGMP_V1_HOST_MEMBERSHIP_QUERY:     /* 0x11 v1/v2/v3 */
 812                 if ( (pinfo->iplen-pinfo->iphdrlen)>=12 ) {
 813                         /* version 3 */
 814                         offset = dissect_igmp_v3_query(tvb, pinfo, tree, type, offset);
 815                 } else {
 816                         /* v1 and v2 differs in second byte of header */
 817                         if (tvb_get_guint8(tvb, offset+1)) {
 818                                 offset = dissect_igmp_v2(tvb, pinfo, tree, type, offset);
 819                         } else {
 820                                 offset = dissect_igmp_v1(tvb, pinfo, tree, type, offset);
 821                         }
 822                 }
 823                 break;
 824
 825         case IGMP_V1_HOST_MEMBERSHIP_REPORT:    /* 0x12  v1 only */
 826                 offset = dissect_igmp_v1(tvb, pinfo, tree, type, offset);
 827                 break;
 828
 829         case IGMP_DVMRP:
 830                 offset = dissect_dvmrp(tvb, pinfo, parent_tree, offset);
 831                 break;
 832
 833         case IGMP_V1_PIM_ROUTING_MESSAGE:
 834                 offset = dissect_pimv1(tvb, pinfo, parent_tree, offset);
 835                 break;
 836
 837         case IGMP_V2_MEMBERSHIP_REPORT:
 838         case IGMP_V2_LEAVE_GROUP:
 839                 offset = dissect_igmp_v2(tvb, pinfo, tree, type, offset);
 840                 break;
 841
 842         case IGMP_TRACEROUTE_RESPONSE:
 843         case IGMP_TRACEROUTE_QUERY_REQ:
 844                 offset = dissect_igmp_mtrace(tvb, pinfo, tree, type, offset);
 845                 break;
 846
 847         case IGMP_V3_MEMBERSHIP_REPORT:
 848                 offset = dissect_igmp_v3_response(tvb, pinfo, tree, type, offset);
 849                 break;
 850
 851         case IGMP_TYPE_0x23:
 852                 dst = g_htonl(MC_ALL_IGMPV3_ROUTERS);
 853                 if (!memcmp(pinfo->dst.data, &dst, 4)) {
 854                         offset = dissect_msnip(tvb, pinfo, parent_tree, offset);
 855                 }
 856                 break;
 857
 858         case IGMP_TYPE_0x24:
 859                 dst = g_htonl(MC_ALL_ROUTERS);
 860                 if (!memcmp(pinfo->dst.data, &dst, 4)) {
 861                         offset = dissect_mrdisc(tvb, pinfo, parent_tree, offset);
 862                 }
 863                 dst = g_htonl(MC_ALL_IGMPV3_ROUTERS);
 864                 if (!memcmp(pinfo->dst.data, &dst, 4)) {
 865                         offset = dissect_msnip(tvb, pinfo, parent_tree, offset);
 866                 }
 867                 break;
 868
 869         case IGMP_TYPE_0x25:
 870                 if ( (pinfo->iplen-pinfo->iphdrlen)>=8 ) {
 871                         /* if len of igmp packet>=8 we assume it is MSNIP */
 872                         offset = dissect_msnip(tvb, pinfo, parent_tree, offset);
 873                 } else {
 874                         /* ok its not MSNIP, check if it might be MRDISC */
 875                         dst = g_htonl(MC_ALL_ROUTERS);
 876                         if (!memcmp(pinfo->dst.data, &dst, 4)) {
 877                                 offset = dissect_mrdisc(tvb, pinfo, parent_tree, offset);
 878                         }
 879                 }
 880                 break;
 881
 882         case IGMP_TYPE_0x26:
 883                 dst = g_htonl(MC_ALL_ROUTERS);
 884                 if (!memcmp(pinfo->dst.data, &dst, 4)) {
 885                         offset = dissect_mrdisc(tvb, pinfo, parent_tree, offset);
 886                 }
 887                 break;
 888
 889         case IGMP_IGAP_JOIN:
 890         case IGMP_IGAP_QUERY:
 891         case IGMP_IGAP_LEAVE:
 892                 offset = dissect_igap(tvb, pinfo, parent_tree, offset);
 893                 break;
 894
 895         default:
 896                 offset = dissect_igmp_unknown(tvb, pinfo, tree, type, offset);
 897                 break;
 898         }
 899
 900
 901         proto_item_set_len(item, offset);
 902 }
 903
 904 void
 905 proto_register_igmp(void)
 906 {
 907         static hf_register_info hf[] = {
 908                 { &hf_type,
 909                         { "Type", "igmp.type", FT_UINT8, BASE_HEX,
 910                           VALS(commands), 0, "IGMP Packet Type", HFILL }},
 911
 912                 { &hf_version,
 913                         { "IGMP Version", "igmp.version", FT_UINT8, BASE_DEC,
 914                           NULL, 0, "IGMP Version", HFILL }},
 915
 916                 { &hf_group_type,
 917                         { "Type Of Group", "igmp.group_type", FT_UINT8, BASE_DEC,
 918                           VALS(vs_group_type), 0, "IGMP V0 Type Of Group", HFILL }},
 919
 920                 { &hf_reply_code,
 921                         { "Reply", "igmp.reply", FT_UINT8, BASE_DEC,
 922                           VALS(vs_reply_code), 0, "IGMP V0 Reply", HFILL }},
 923
 924                 { &hf_reply_pending,
 925                         { "Reply Pending", "igmp.reply.pending", FT_UINT8, BASE_DEC,
 926                           NULL, 0, "IGMP V0 Reply Pending, Retry in this many seconds", HFILL }},
 927
 928                 { &hf_checksum,
 929                         { "Checksum", "igmp.checksum", FT_UINT16, BASE_HEX,
 930                           NULL, 0, "IGMP Checksum", HFILL }},
 931
 932                 { &hf_checksum_bad,
 933                         { "Bad Checksum", "igmp.checksum_bad", FT_BOOLEAN, BASE_NONE,
 934                           NULL, 0, "Bad IGMP Checksum", HFILL }},
 935
 936                 { &hf_identifier,
 937                         { "Identifier", "igmp.identifier", FT_UINT32, BASE_DEC,
 938                           NULL, 0, "IGMP V0 Identifier", HFILL }},
 939
 940                 { &hf_access_key,
 941                         { "Access Key", "igmp.access_key", FT_BYTES, BASE_HEX,
 942                           NULL, 0, "IGMP V0 Access Key", HFILL }},
 943
 944                 { &hf_max_resp,
 945                         { "Max Resp Time", "igmp.max_resp", FT_UINT8, BASE_DEC,
 946                           NULL, 0, "Max Response Time", HFILL }},
 947
 948                 { &hf_suppress,
 949                         { "S", "igmp.s", FT_BOOLEAN, 8,
 950                           TFS(&tfs_s), IGMP_V3_S, "Suppress Router Side Processing", HFILL }},
 951
 952                 { &hf_qrv,
 953                         { "QRV", "igmp.qrv", FT_UINT8, BASE_DEC,
 954                         NULL, IGMP_V3_QRV_MASK, "Querier's Robustness Value", HFILL }},
 955
 956                 { &hf_qqic,
 957                         { "QQIC", "igmp.qqic", FT_UINT8, BASE_DEC,
 958                           NULL, 0, "Querier's Query Interval Code", HFILL }},
 959
 960                 { &hf_num_src,
 961                         { "Num Src", "igmp.num_src", FT_UINT16, BASE_DEC,
 962                           NULL, 0, "Number Of Sources", HFILL }},
 963
 964                 { &hf_saddr,
 965                         { "Source Address", "igmp.saddr", FT_IPv4, BASE_NONE,
 966                           NULL, 0, "Source Address", HFILL }},
 967
 968                 { &hf_num_grp_recs,
 969                         { "Num Group Records", "igmp.num_grp_recs", FT_UINT16, BASE_DEC,
 970                           NULL, 0, "Number Of Group Records", HFILL }},
 971
 972                 { &hf_record_type,
 973                         { "Record Type", "igmp.record_type", FT_UINT8, BASE_DEC,
 974                         VALS(vs_record_type), 0, "Record Type", HFILL }},
 975
 976                 { &hf_aux_data_len,
 977                         { "Aux Data Len", "igmp.aux_data_len", FT_UINT8, BASE_DEC,
 978                         NULL, 0, "Aux Data Len, In units of 32bit words", HFILL }},
 979
 980                 { &hf_maddr,
 981                         { "Multicast Address", "igmp.maddr", FT_IPv4, BASE_NONE,
 982                           NULL, 0, "Multicast Address", HFILL }},
 983
 984                 { &hf_aux_data,
 985                         { "Aux Data", "igmp.aux_data", FT_BYTES, BASE_HEX,
 986                           NULL, 0, "IGMP V3 Auxiliary Data", HFILL }},
 987
 988                 { &hf_max_resp_exp,
 989                         { "Exponent", "igmp.max_resp.exp", FT_UINT8, BASE_HEX,
 990                         NULL, IGMP_MAX_RESP_EXP, "Maxmimum Response Time, Exponent", HFILL }},
 991
 992                 { &hf_max_resp_mant,
 993                         { "Mantissa", "igmp.max_resp.mant", FT_UINT8, BASE_HEX,
 994                         NULL, IGMP_MAX_RESP_MANT, "Maxmimum Response Time, Mantissa", HFILL }},
 995
 996                 { &hf_mtrace_max_hops,
 997                         { "# hops", "igmp.mtrace.max_hops", FT_UINT8, BASE_DEC,
 998                         NULL, 0, "Maxmimum Number of Hops to Trace", HFILL }},
 999
1000                 { &hf_mtrace_saddr,
1001                         { "Source Address", "igmp.mtrace.saddr", FT_IPv4, BASE_NONE,
1002                           NULL, 0, "Multicast Source for the Path Being Traced", HFILL }},
1003
1004                 { &hf_mtrace_raddr,
1005                         { "Receiver Address", "igmp.mtrace.raddr", FT_IPv4, BASE_NONE,
1006                           NULL, 0, "Multicast Receiver for the Path Being Traced", HFILL }},
1007
1008                 { &hf_mtrace_rspaddr,
1009                         { "Response Address", "igmp.mtrace.rspaddr", FT_IPv4, BASE_NONE,
1010                           NULL, 0, "Destination of Completed Traceroute Response", HFILL }},
1011
1012                 { &hf_mtrace_resp_ttl,
1013                         { "Response TTL", "igmp.mtrace.resp_ttl", FT_UINT8, BASE_DEC,
1014                         NULL, 0, "TTL for Multicasted Responses", HFILL }},
1015
1016                 { &hf_mtrace_q_id,
1017                         { "Query ID", "igmp.mtrace.q_id", FT_UINT24, BASE_DEC,
1018                         NULL, 0, "Identifier for this Traceroute Request", HFILL }},
1019
1020                 { &hf_mtrace_q_arrival,
1021                         { "Query Arrival", "igmp.mtrace.q_arrival", FT_UINT32, BASE_DEC,
1022                         NULL, 0, "Query Arrival Time", HFILL }},
1023
1024                 { &hf_mtrace_q_inaddr,
1025                         { "In itf addr", "igmp.mtrace.q_inaddr", FT_IPv4, BASE_NONE,
1026                         NULL, 0, "Incoming Interface Address", HFILL }},
1027
1028                 { &hf_mtrace_q_outaddr,
1029                         { "Out itf addr", "igmp.mtrace.q_outaddr", FT_IPv4, BASE_NONE,
1030                         NULL, 0, "Outgoing Interface Address", HFILL }},
1031
1032                 { &hf_mtrace_q_prevrtr,
1033                         { "Previous rtr addr", "igmp.mtrace.q_prevrtr", FT_IPv4, BASE_NONE,
1034                         NULL, 0, "Previous-Hop Router Address", HFILL }},
1035
1036                 { &hf_mtrace_q_inpkt,
1037                         { "In pkts", "igmp.mtrace.q_inpkt", FT_UINT32, BASE_DEC,
1038                         NULL, 0, "Input packet count on incoming interface", HFILL }},
1039
1040                 { &hf_mtrace_q_outpkt,
1041                         { "Out pkts", "igmp.mtrace.q_outpkt", FT_UINT32, BASE_DEC,
1042                         NULL, 0, "Output packet count on outgoing interface", HFILL }},
1043
1044                 { &hf_mtrace_q_total,
1045                         { "S,G pkt count", "igmp.mtrace.q_total", FT_UINT32, BASE_DEC,
1046                         NULL, 0, "Total number of packets for this source-group pair", HFILL }},
1047
1048                 { &hf_mtrace_q_rtg_proto,
1049                         { "Rtg Protocol", "igmp.mtrace.q_rtg_proto", FT_UINT8, BASE_DEC,
1050                         VALS(&mtrace_rtg_vals), 0, "Routing protocol between this and previous hop rtr", HFILL }},
1051
1052                 { &hf_mtrace_q_fwd_ttl,
1053                         { "FwdTTL", "igmp.mtrace.q_fwd_ttl", FT_UINT8, BASE_DEC,
1054                         NULL, 0, "TTL required for forwarding", HFILL }},
1055
1056                 { &hf_mtrace_q_mbz,
1057                         { "MBZ", "igmp.mtrace.q_mbz", FT_UINT8, BASE_HEX,
1058                         NULL, 0x80, "Must be zeroed on transmission and ignored on reception", HFILL }},
1059
1060                 { &hf_mtrace_q_s,
1061                         { "S", "igmp.mtrace.q_s", FT_UINT8, BASE_HEX,
1062                         NULL, 0x40, "Set if S,G packet count is for source network", HFILL }},
1063
1064                 { &hf_mtrace_q_src_mask,
1065                         { "Src Mask", "igmp.mtrace.q_src_mask", FT_UINT8, BASE_HEX,
1066                         NULL, 0x3F, "Source mask length. 63 when forwarding on group state", HFILL }},
1067
1068                 { &hf_mtrace_q_fwd_code,
1069                         { "Forwarding Code", "igmp.mtrace.q_fwd_code", FT_UINT8, BASE_HEX,
1070                         VALS(&mtrace_fwd_code_vals), 0, "Forwarding information/error code", HFILL }},
1071
1072         };
1073         static gint *ett[] = {
1074                 &ett_igmp,
1075                 &ett_group_record,
1076                 &ett_sqrv_bits,
1077                 &ett_max_resp,
1078                 &ett_mtrace_block,
1079         };
1080
1081         proto_igmp = proto_register_protocol("Internet Group Management Protocol",
1082             "IGMP", "igmp");
1083         proto_register_field_array(proto_igmp, hf, array_length(hf));
1084         proto_register_subtree_array(ett, array_length(ett));
1085 }
1086
1087 void
1088 proto_reg_handoff_igmp(void)
1089 {
1090         dissector_handle_t igmp_handle;
1091
1092         igmp_handle = create_dissector_handle(dissect_igmp, proto_igmp);
1093         dissector_add("ip.proto", IP_PROTO_IGMP, igmp_handle);
1094 }