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 <glib.h>
  35
  36 #include <epan/packet.h>
  37 #include <packet-tcp.h>
  38
  39 void proto_register_turnchannel(void);
  40 void proto_reg_handoff_turnchannel(void);
  41
  42 /* heuristic subdissectors */
  43 static heur_dissector_list_t heur_subdissector_list;
  44
  45 /* data dissector handle */
  46 static dissector_handle_t data_handle;
  47
  48 /* Initialize the protocol and registered fields */
  49 static int proto_turnchannel = -1;
  50
  51 static int hf_turnchannel_id = -1;
  52 static int hf_turnchannel_len = -1;
  53
  54 #define TURNCHANNEL_HDR_LEN     ((guint)4)
  55
  56
  57 /* Initialize the subtree pointers */
  58 static gint ett_turnchannel = -1;
  59
  60 static int
  61 dissect_turnchannel_message(tvbuff_t *tvb, packet_info *pinfo,
  62                             proto_tree *tree, void *data _U_)
  63 {
  64         guint   len;
  65         guint16 channel_id;
  66         guint16 data_len;
  67         proto_item *ti;
  68         proto_tree *turnchannel_tree;
  69         heur_dtbl_entry_t *hdtbl_entry;
  70
  71         len = tvb_length(tvb);
  72         /* First, make sure we have enough data to do the check. */
  73         if (len < TURNCHANNEL_HDR_LEN) {
  74                   return 0;
  75         }
  76
  77         channel_id = tvb_get_ntohs(tvb, 0);
  78         data_len = tvb_get_ntohs(tvb, 2);
  79
  80         if ((channel_id < 0x4000) || (channel_id > 0xFFFE)) {
  81           return 0;
  82         }
  83
  84         if (len != TURNCHANNEL_HDR_LEN + data_len) {
  85           return 0;
  86         }
  87
  88         /* Seems to be a decent TURN channel message */
  89         col_set_str(pinfo->cinfo, COL_PROTOCOL, "TURN CHANNEL");
  90
  91         col_add_fstr(pinfo->cinfo, COL_INFO, "Channel Id 0x%x", channel_id);
  92
  93         ti = proto_tree_add_item(tree, proto_turnchannel, tvb, 0, -1, ENC_NA);
  94
  95         turnchannel_tree = proto_item_add_subtree(ti, ett_turnchannel);
  96
  97         proto_tree_add_uint(turnchannel_tree, hf_turnchannel_id, tvb, 0, 2, channel_id);
  98         proto_tree_add_uint(turnchannel_tree, hf_turnchannel_len, tvb, 2, 2, data_len);
  99
 100
 101         if (len > TURNCHANNEL_HDR_LEN) {
 102           tvbuff_t *next_tvb;
 103           guint reported_len, new_len;
 104
 105           new_len = tvb_length_remaining(tvb, TURNCHANNEL_HDR_LEN);
 106           reported_len = tvb_reported_length_remaining(tvb,
 107                                                        TURNCHANNEL_HDR_LEN);
 108           if (data_len < reported_len) {
 109             reported_len = data_len;
 110           }
 111           next_tvb = tvb_new_subset(tvb, TURNCHANNEL_HDR_LEN, new_len,
 112                                     reported_len);
 113
 114
 115           if (!dissector_try_heuristic(heur_subdissector_list,
 116                                        next_tvb, pinfo, tree, &hdtbl_entry, NULL)) {
 117             call_dissector(data_handle,next_tvb, pinfo, tree);
 118           }
 119         }
 120
 121         return tvb_length(tvb);
 122 }
 123
 124 static guint
 125 get_turnchannel_message_len(packet_info *pinfo _U_, tvbuff_t *tvb, int offset)
 126 {
 127         return (guint)tvb_get_ntohs(tvb, offset+2) + TURNCHANNEL_HDR_LEN;
 128 }
 129
 130 static int
 131 dissect_turnchannel_tcp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data)
 132 {
 133         tcp_dissect_pdus(tvb, pinfo, tree, TRUE, TURNCHANNEL_HDR_LEN,
 134                         get_turnchannel_message_len, dissect_turnchannel_message, data);
 135         return tvb_length(tvb);
 136 }
 137
 138
 139 static gboolean
 140 dissect_turnchannel_heur(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
 141 {
 142         guint   len;
 143         guint16 channel_id;
 144         guint16 data_len;
 145
 146         len = tvb_length(tvb);
 147         /* First, make sure we have enough data to do the check. */
 148         if (len < TURNCHANNEL_HDR_LEN) {
 149                   return FALSE;
 150         }
 151
 152         channel_id = tvb_get_ntohs(tvb, 0);
 153         data_len = tvb_get_ntohs(tvb, 2);
 154
 155         if ((channel_id < 0x4000) || (channel_id > 0xFFFE)) {
 156           return FALSE;
 157         }
 158
 159         if (len != TURNCHANNEL_HDR_LEN + data_len) {
 160           return FALSE;
 161         }
 162
 163         return dissect_turnchannel_message(tvb, pinfo, tree, NULL);
 164 }
 165
 166 void
 167 proto_register_turnchannel(void)
 168 {
 169         static hf_register_info hf[] = {
 170                 { &hf_turnchannel_id,
 171                         { "TURN Channel ID",    "turnchannel.id",       FT_UINT16,
 172                         BASE_HEX,       NULL,   0x0,    NULL,   HFILL }
 173                 },
 174                 { &hf_turnchannel_len,
 175                         { "Data Length",  "turnchannel.length", FT_UINT16,
 176                         BASE_DEC,       NULL,   0x0,    NULL,   HFILL }
 177                 },
 178         };
 179
 180 /* Setup protocol subtree array */
 181         static gint *ett[] = {
 182                 &ett_turnchannel,
 183         };
 184
 185 /* Register the protocol name and description */
 186         proto_turnchannel = proto_register_protocol("TURN Channel",
 187             "TURNCHANNEL", "turnchannel");
 188
 189         new_register_dissector("turnchannel", dissect_turnchannel_message,
 190                            proto_turnchannel);
 191
 192 /* subdissectors */
 193         heur_subdissector_list = register_heur_dissector_list("turnchannel");
 194
 195 /* Required function calls to register the header fields and subtrees used */
 196         proto_register_field_array(proto_turnchannel, hf, array_length(hf));
 197         proto_register_subtree_array(ett, array_length(ett));
 198
 199 }
 200
 201
 202 void
 203 proto_reg_handoff_turnchannel(void)
 204 {
 205         dissector_handle_t turnchannel_tcp_handle;
 206         dissector_handle_t turnchannel_udp_handle;
 207
 208         turnchannel_tcp_handle = new_create_dissector_handle(dissect_turnchannel_tcp, proto_turnchannel);
 209         turnchannel_udp_handle = find_dissector("turnchannel");
 210
 211         /* Register for "Decode As" in case STUN negotiation isn't captured */
 212         dissector_add_for_decode_as("tcp.port", turnchannel_tcp_handle);
 213         dissector_add_for_decode_as("udp.port", turnchannel_udp_handle);
 214
 215         /* TURN negotiation is handled through STUN2 dissector (packet-stun.c),
 216            so only it should be able to determine if a packet is a TURN packet */
 217         heur_dissector_add("stun", dissect_turnchannel_heur, proto_turnchannel);
 218
 219         data_handle = find_dissector("data");
 220 }
 221
 222 /*
 223  * Editor modelines  -  http://www.wireshark.org/tools/modelines.html
 224  *
 225  * Local variables:
 226  * c-basic-offset: 8
 227  * tab-width: 8
 228  * indent-tabs-mode: t
 229  * End:
 230  *
 231  * vi: set shiftwidth=8 tabstop=8 noexpandtab:
 232  * :indentSize=8:tabSize=8:noTabs=false:
 233  */