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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 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 #include "config.h"
  35
  36 #include <glib.h>
  37
  38 #include <epan/packet.h>
  39 #include <packet-tcp.h>
  40
  41 /* heuristic subdissectors */
  42 static heur_dissector_list_t heur_subdissector_list;
  43
  44 /* data dissector handle */
  45 static dissector_handle_t data_handle;
  46
  47 /* Initialize the protocol and registered fields */
  48 static int proto_turnchannel = -1;
  49
  50 static int hf_turnchannel_id = -1;
  51 static int hf_turnchannel_len = -1;
  52
  53 #define TURNCHANNEL_HDR_LEN     ((guint)4)
  54
  55
  56 /* Initialize the subtree pointers */
  57 static gint ett_turnchannel = -1;
  58
  59 static int
  60 dissect_turnchannel_message(tvbuff_t *tvb, packet_info *pinfo,
  61                             proto_tree *tree, void *data _U_)
  62 {
  63         guint   len;
  64         guint16 channel_id;
  65         guint16 data_len;
  66         proto_item *ti;
  67         proto_tree *turnchannel_tree;
  68
  69         len = tvb_length(tvb);
  70         /* First, make sure we have enough data to do the check. */
  71         if (len < TURNCHANNEL_HDR_LEN) {
  72                   return 0;
  73         }
  74
  75         channel_id = tvb_get_ntohs(tvb, 0);
  76         data_len = tvb_get_ntohs(tvb, 2);
  77
  78         if ((channel_id < 0x4000) || (channel_id > 0xFFFE)) {
  79           return 0;
  80         }
  81
  82         if (len != TURNCHANNEL_HDR_LEN + data_len) {
  83           return 0;
  84         }
  85
  86         /* Seems to be a decent TURN channel message */
  87         col_set_str(pinfo->cinfo, COL_PROTOCOL, "TURN CHANNEL");
  88
  89         col_add_fstr(pinfo->cinfo, COL_INFO, "Channel Id 0x%x", channel_id);
  90
  91         ti = proto_tree_add_item(tree, proto_turnchannel, tvb, 0, -1, ENC_NA);
  92
  93         turnchannel_tree = proto_item_add_subtree(ti, ett_turnchannel);
  94
  95         proto_tree_add_uint(turnchannel_tree, hf_turnchannel_id, tvb, 0, 2, channel_id);
  96         proto_tree_add_uint(turnchannel_tree, hf_turnchannel_len, tvb, 2, 2, data_len);
  97
  98
  99         if (len > TURNCHANNEL_HDR_LEN) {
 100           tvbuff_t *next_tvb;
 101           guint reported_len, new_len;
 102
 103           new_len = tvb_length_remaining(tvb, TURNCHANNEL_HDR_LEN);
 104           reported_len = tvb_reported_length_remaining(tvb,
 105                                                        TURNCHANNEL_HDR_LEN);
 106           if (data_len < reported_len) {
 107             reported_len = data_len;
 108           }
 109           next_tvb = tvb_new_subset(tvb, TURNCHANNEL_HDR_LEN, new_len,
 110                                     reported_len);
 111
 112
 113           if (!dissector_try_heuristic(heur_subdissector_list,
 114                                        next_tvb, pinfo, tree, NULL)) {
 115             call_dissector(data_handle,next_tvb, pinfo, tree);
 116           }
 117         }
 118
 119         return tvb_length(tvb);
 120 }
 121
 122 static guint
 123 get_turnchannel_message_len(packet_info *pinfo _U_, tvbuff_t *tvb, int offset)
 124 {
 125         return (guint)tvb_get_ntohs(tvb, offset+2) + TURNCHANNEL_HDR_LEN;
 126 }
 127
 128 static int
 129 dissect_turnchannel_tcp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data)
 130 {
 131         tcp_dissect_pdus(tvb, pinfo, tree, TRUE, TURNCHANNEL_HDR_LEN,
 132                         get_turnchannel_message_len, dissect_turnchannel_message, data);
 133         return tvb_length(tvb);
 134 }
 135
 136
 137 static gboolean
 138 dissect_turnchannel_heur(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
 139 {
 140         guint   len;
 141         guint16 channel_id;
 142         guint16 data_len;
 143
 144         len = tvb_length(tvb);
 145         /* First, make sure we have enough data to do the check. */
 146         if (len < TURNCHANNEL_HDR_LEN) {
 147                   return FALSE;
 148         }
 149
 150         channel_id = tvb_get_ntohs(tvb, 0);
 151         data_len = tvb_get_ntohs(tvb, 2);
 152
 153         if ((channel_id < 0x4000) || (channel_id > 0xFFFE)) {
 154           return FALSE;
 155         }
 156
 157         if (len != TURNCHANNEL_HDR_LEN + data_len) {
 158           return FALSE;
 159         }
 160
 161         return dissect_turnchannel_message(tvb, pinfo, tree, NULL);
 162 }
 163
 164 void
 165 proto_register_turnchannel(void)
 166 {
 167         static hf_register_info hf[] = {
 168                 { &hf_turnchannel_id,
 169                         { "TURN Channel ID",    "turnchannel.id",       FT_UINT16,
 170                         BASE_HEX,       NULL,   0x0,    NULL,   HFILL }
 171                 },
 172                 { &hf_turnchannel_len,
 173                         { "Data Length",  "turnchannel.length", FT_UINT16,
 174                         BASE_DEC,       NULL,   0x0,    NULL,   HFILL }
 175                 },
 176         };
 177
 178 /* Setup protocol subtree array */
 179         static gint *ett[] = {
 180                 &ett_turnchannel,
 181         };
 182
 183 /* Register the protocol name and description */
 184         proto_turnchannel = proto_register_protocol("TURN Channel",
 185             "TURNCHANNEL", "turnchannel");
 186
 187         new_register_dissector("turnchannel", dissect_turnchannel_message,
 188                            proto_turnchannel);
 189
 190 /* subdissectors */
 191         register_heur_dissector_list("turnchannel", &heur_subdissector_list);
 192
 193 /* Required function calls to register the header fields and subtrees used */
 194         proto_register_field_array(proto_turnchannel, hf, array_length(hf));
 195         proto_register_subtree_array(ett, array_length(ett));
 196
 197 }
 198
 199
 200 void
 201 proto_reg_handoff_turnchannel(void)
 202 {
 203         dissector_handle_t turnchannel_tcp_handle;
 204         dissector_handle_t turnchannel_udp_handle;
 205
 206         turnchannel_tcp_handle = new_create_dissector_handle(dissect_turnchannel_tcp, proto_turnchannel);
 207         turnchannel_udp_handle = find_dissector("turnchannel");
 208
 209         /* Used for "Decode As" in case STUN negotiation isn't captured */
 210         dissector_add_handle("tcp.port", turnchannel_tcp_handle);
 211         dissector_add_handle("udp.port", turnchannel_udp_handle);
 212
 213         /* TURN negoiation is handled through STUN2 dissector (packet-stun.c),
 214            so only it should be able to determine if a packet is a TURN packet */
 215         heur_dissector_add("stun", dissect_turnchannel_heur, proto_turnchannel);
 216
 217         data_handle = find_dissector("data");
 218 }