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  * 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  23  *
  24  * Please refer to the following specs for protocol detail:
  25  * - draft-ietf-behave-rfc3489bis-15
  26  * - draft-ietf-mmusic-ice-19
  27  * - draft-ietf-behave-nat-behavior-discovery-03
  28  * - draft-ietf-behave-turn-07
  29  * - draft-ietf-behave-turn-ipv6-03
  30  */
  31
  32 #include "config.h"
  33
  34 #include <epan/packet.h>
  35 #include "packet-tcp.h"
  36
  37 void proto_register_turnchannel(void);
  38 void proto_reg_handoff_turnchannel(void);
  39
  40 /* heuristic subdissectors */
  41 static heur_dissector_list_t heur_subdissector_list;
  42
  43 /* data dissector handle */
  44 static dissector_handle_t data_handle;
  45
  46 /* Initialize the protocol and registered fields */
  47 static int proto_turnchannel = -1;
  48
  49 static int hf_turnchannel_id = -1;
  50 static int hf_turnchannel_len = -1;
  51
  52 #define TURNCHANNEL_HDR_LEN     ((guint)4)
  53
  54
  55 /* Initialize the subtree pointers */
  56 static gint ett_turnchannel = -1;
  57
  58 static int
  59 dissect_turnchannel_message(tvbuff_t *tvb, packet_info *pinfo,
  60                             proto_tree *tree, void *data _U_)
  61 {
  62         guint   len;
  63         guint16 channel_id;
  64         guint16 data_len;
  65         proto_item *ti;
  66         proto_tree *turnchannel_tree;
  67         heur_dtbl_entry_t *hdtbl_entry;
  68
  69         len = tvb_captured_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_captured_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, &hdtbl_entry, NULL)) {
 115             call_dissector(data_handle,next_tvb, pinfo, tree);
 116           }
 117         }
 118
 119         return tvb_captured_length(tvb);
 120 }
 121
 122 static guint
 123 get_turnchannel_message_len(packet_info *pinfo _U_, tvbuff_t *tvb,
 124                             int offset, void *data _U_)
 125 {
 126         return (guint)tvb_get_ntohs(tvb, offset+2) + TURNCHANNEL_HDR_LEN;
 127 }
 128
 129 static int
 130 dissect_turnchannel_tcp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data)
 131 {
 132         tcp_dissect_pdus(tvb, pinfo, tree, TRUE, TURNCHANNEL_HDR_LEN,
 133                         get_turnchannel_message_len, dissect_turnchannel_message, data);
 134         return tvb_captured_length(tvb);
 135 }
 136
 137
 138 static gboolean
 139 dissect_turnchannel_heur(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
 140 {
 141         guint   len;
 142         guint16 channel_id;
 143         guint16 data_len;
 144
 145         len = tvb_captured_length(tvb);
 146         /* First, make sure we have enough data to do the check. */
 147         if (len < TURNCHANNEL_HDR_LEN) {
 148                   return FALSE;
 149         }
 150
 151         channel_id = tvb_get_ntohs(tvb, 0);
 152         data_len = tvb_get_ntohs(tvb, 2);
 153
 154         if ((channel_id < 0x4000) || (channel_id > 0xFFFE)) {
 155           return FALSE;
 156         }
 157
 158         if (len != TURNCHANNEL_HDR_LEN + data_len) {
 159           return FALSE;
 160         }
 161
 162         return dissect_turnchannel_message(tvb, pinfo, tree, NULL);
 163 }
 164
 165 void
 166 proto_register_turnchannel(void)
 167 {
 168         static hf_register_info hf[] = {
 169                 { &hf_turnchannel_id,
 170                         { "TURN Channel ID",    "turnchannel.id",       FT_UINT16,
 171                         BASE_HEX,       NULL,   0x0,    NULL,   HFILL }
 172                 },
 173                 { &hf_turnchannel_len,
 174                         { "Data Length",  "turnchannel.length", FT_UINT16,
 175                         BASE_DEC,       NULL,   0x0,    NULL,   HFILL }
 176                 },
 177         };
 178
 179 /* Setup protocol subtree array */
 180         static gint *ett[] = {
 181                 &ett_turnchannel,
 182         };
 183
 184 /* Register the protocol name and description */
 185         proto_turnchannel = proto_register_protocol("TURN Channel",
 186             "TURNCHANNEL", "turnchannel");
 187
 188         new_register_dissector("turnchannel", dissect_turnchannel_message,
 189                            proto_turnchannel);
 190
 191 /* subdissectors */
 192         heur_subdissector_list = register_heur_dissector_list("turnchannel");
 193
 194 /* Required function calls to register the header fields and subtrees used */
 195         proto_register_field_array(proto_turnchannel, hf, array_length(hf));
 196         proto_register_subtree_array(ett, array_length(ett));
 197
 198 }
 199
 200
 201 void
 202 proto_reg_handoff_turnchannel(void)
 203 {
 204         dissector_handle_t turnchannel_tcp_handle;
 205         dissector_handle_t turnchannel_udp_handle;
 206
 207         turnchannel_tcp_handle = create_dissector_handle(dissect_turnchannel_tcp, proto_turnchannel);
 208         turnchannel_udp_handle = find_dissector("turnchannel");
 209
 210         /* Register for "Decode As" in case STUN negotiation isn't captured */
 211         dissector_add_for_decode_as("tcp.port", turnchannel_tcp_handle);
 212         dissector_add_for_decode_as("udp.port", turnchannel_udp_handle);
 213
 214         /* TURN negotiation is handled through STUN2 dissector (packet-stun.c),
 215            so only it should be able to determine if a packet is a TURN packet */
 216         heur_dissector_add("stun", dissect_turnchannel_heur, "TURN Channel over STUN", "turnchannel_stun", proto_turnchannel, HEURISTIC_ENABLE);
 217
 218         data_handle = find_dissector("data");
 219 }
 220
 221 /*
 222  * Editor modelines  -  http://www.wireshark.org/tools/modelines.html
 223  *
 224  * Local variables:
 225  * c-basic-offset: 8
 226  * tab-width: 8
 227  * indent-tabs-mode: t
 228  * End:
 229  *
 230  * vi: set shiftwidth=8 tabstop=8 noexpandtab:
 231  * :indentSize=8:tabSize=8:noTabs=false:
 232  */