epan/dissectors/packet-turnchannel.c

   1 /* packet-turnchannel.c
   2  * Routines for TURN channel dissection (TURN negociation is handled
   3  * in the STUN2 dissector
   4  * Copyright 2008, 8x8 Inc. <petithug@8x8.com>
   5  *
   6  * $Id$
   7  *
   8  * Wireshark - Network traffic analyzer
   9  * By Gerald Combs <gerald@wireshark.org>
  10  * Copyright 1998 Gerald Combs
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License
  14  * as published by the Free Software Foundation; either version 2
  15  * of the License, or (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with this program; if not, write to the Free Software
  24  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  25  *
  26  * Please refer to the following specs for protocol detail:
  27  * - draft-ietf-behave-rfc3489bis-15
  28  * - draft-ietf-mmusic-ice-19
  29  * - draft-ietf-behave-nat-behavior-discovery-03
  30  * - draft-ietf-behave-turn-07
  31  * - draft-ietf-behave-turn-ipv6-03
  32  */
  33
  34 #ifdef HAVE_CONFIG_H
  35 # include "config.h"
  36 #endif
  37
  38 #include <stdio.h>
  39 #include <stdlib.h>
  40 #include <string.h>
  41
  42 #include <glib.h>
  43
  44 #include <epan/packet.h>
  45 #include <packet-tcp.h>
  46
  47 /* heuristic subdissectors */
  48 static heur_dissector_list_t heur_subdissector_list;
  49
  50 /* data dissector handle */
  51 static dissector_handle_t data_handle;
  52
  53 /* Initialize the protocol and registered fields */
  54 static int proto_turnchannel = -1;
  55
  56 static int hf_turnchannel_id = -1;
  57 static int hf_turnchannel_len = -1;
  58
  59 #define TURNCHANNEL_HDR_LEN     ((guint)4)
  60
  61
  62 /* Initialize the subtree pointers */
  63 static gint ett_turnchannel = -1;
  64
  65 static int
  66 dissect_turnchannel_message(tvbuff_t *tvb, packet_info *pinfo,
  67                             proto_tree *tree)
  68 {
  69         guint   len;
  70         guint16 channel_id;
  71         guint16 data_len;
  72         proto_item *ti;
  73         proto_tree *turnchannel_tree;
  74
  75         len = tvb_length(tvb);
  76         /* First, make sure we have enough data to do the check. */
  77         if (len < TURNCHANNEL_HDR_LEN) {
  78                   return 0;
  79         }
  80
  81         channel_id = tvb_get_ntohs(tvb, 0);
  82         data_len = tvb_get_ntohs(tvb, 2);
  83
  84         if ((channel_id < 0x4000) || (channel_id > 0xFFFE)) {
  85           return 0;
  86         }
  87
  88         if (len != TURNCHANNEL_HDR_LEN + data_len) {
  89           return 0;
  90         }
  91
  92         /* Seems to be a decent TURN channel message */
  93         if (check_col(pinfo->cinfo, COL_PROTOCOL))
  94                 col_set_str(pinfo->cinfo, COL_PROTOCOL, "TURN CHANNEL");
  95
  96         if (check_col(pinfo->cinfo, COL_INFO))
  97           col_add_fstr(pinfo->cinfo, COL_INFO, "Channel Id 0x%x", channel_id);
  98
  99         if (!tree)
 100           return tvb_length(tvb);
 101
 102         ti = proto_tree_add_item(tree, proto_turnchannel, tvb, 0, -1, FALSE);
 103
 104         turnchannel_tree = proto_item_add_subtree(ti, ett_turnchannel);
 105
 106         proto_tree_add_uint(turnchannel_tree, hf_turnchannel_id, tvb, 0, 2, channel_id);
 107         proto_tree_add_uint(turnchannel_tree, hf_turnchannel_len, tvb, 2, 2, data_len);
 108
 109
 110         if (len > TURNCHANNEL_HDR_LEN) {
 111           tvbuff_t *next_tvb;
 112           guint reported_len, new_len;
 113
 114           new_len = tvb_length_remaining(tvb, TURNCHANNEL_HDR_LEN);
 115           reported_len = tvb_reported_length_remaining(tvb,
 116                                                        TURNCHANNEL_HDR_LEN);
 117           if (data_len < reported_len) {
 118             reported_len = data_len;
 119           }
 120           next_tvb = tvb_new_subset(tvb, TURNCHANNEL_HDR_LEN, new_len,
 121                                     reported_len);
 122
 123
 124           if (!dissector_try_heuristic(heur_subdissector_list,
 125                                        next_tvb, pinfo, tree)) {
 126             call_dissector(data_handle,next_tvb, pinfo, tree);
 127           }
 128         }
 129
 130         return tvb_length(tvb);
 131 }
 132
 133
 134 static void
 135 dissect_turnchannel_message_no_return(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 136 {
 137         dissect_turnchannel_message(tvb, pinfo, tree);
 138 }
 139
 140
 141 static guint
 142 get_turnchannel_message_len(packet_info *pinfo _U_, tvbuff_t *tvb, int offset)
 143 {
 144         return (guint)tvb_get_ntohs(tvb, offset+2) + TURNCHANNEL_HDR_LEN;
 145 }
 146
 147 static void
 148 dissect_turnchannel_tcp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 149 {
 150         tcp_dissect_pdus(tvb, pinfo, tree, TRUE, TURNCHANNEL_HDR_LEN,
 151                         get_turnchannel_message_len, dissect_turnchannel_message_no_return);
 152 }
 153
 154
 155 static gboolean
 156 dissect_turnchannel_heur(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 157 {
 158         guint   len;
 159         guint16 channel_id;
 160         guint16 data_len;
 161
 162         len = tvb_length(tvb);
 163         /* First, make sure we have enough data to do the check. */
 164         if (len < TURNCHANNEL_HDR_LEN) {
 165                   return FALSE;
 166         }
 167
 168         channel_id = tvb_get_ntohs(tvb, 0);
 169         data_len = tvb_get_ntohs(tvb, 2);
 170
 171         if ((channel_id < 0x4000) || (channel_id > 0xFFFE)) {
 172           return FALSE;
 173         }
 174
 175         if (len != TURNCHANNEL_HDR_LEN + data_len) {
 176           return FALSE;
 177         }
 178
 179         return dissect_turnchannel_message(tvb, pinfo, tree);
 180 }
 181
 182 void
 183 proto_register_turnchannel(void)
 184 {
 185         static hf_register_info hf[] = {
 186                 { &hf_turnchannel_id,
 187                         { "TURN Channel ID",    "turnchannel.id",       FT_UINT16,
 188                         BASE_HEX,       NULL,   0x0,    NULL,   HFILL }
 189                 },
 190                 { &hf_turnchannel_len,
 191                         { "Data Length",  "turnchannel.length", FT_UINT16,
 192                         BASE_DEC,       NULL,   0x0,    NULL,   HFILL }
 193                 },
 194         };
 195
 196 /* Setup protocol subtree array */
 197         static gint *ett[] = {
 198                 &ett_turnchannel,
 199         };
 200
 201 /* Register the protocol name and description */
 202         proto_turnchannel = proto_register_protocol("TURN Channel",
 203             "TURNCHANNEL", "turnchannel");
 204
 205         new_register_dissector("turnchannel", dissect_turnchannel_message,
 206                            proto_turnchannel);
 207
 208 /* subdissectors */
 209         register_heur_dissector_list("turnchannel", &heur_subdissector_list);
 210
 211 /* Required function calls to register the header fields and subtrees used */
 212         proto_register_field_array(proto_turnchannel, hf, array_length(hf));
 213         proto_register_subtree_array(ett, array_length(ett));
 214
 215 }
 216
 217
 218 void
 219 proto_reg_handoff_turnchannel(void)
 220 {
 221         dissector_handle_t turnchannel_tcp_handle;
 222         dissector_handle_t turnchannel_udp_handle;
 223
 224         turnchannel_tcp_handle = create_dissector_handle(dissect_turnchannel_tcp, proto_turnchannel);
 225         turnchannel_udp_handle = find_dissector("turnchannel");
 226
 227         dissector_add_handle("tcp.port", turnchannel_tcp_handle);   /* for decode-as */
 228         dissector_add_handle("udp.port", turnchannel_udp_handle);   /* ...           */
 229
 230         heur_dissector_add("udp", dissect_turnchannel_heur, proto_turnchannel);
 231         heur_dissector_add("tcp", dissect_turnchannel_heur, proto_turnchannel);
 232
 233         data_handle = find_dissector("data");
 234 }