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  * SPDX-License-Identifier: GPL-2.0-or-later
  11  *
  12  * Please refer to the following specs for protocol detail:
  13  * - draft-ietf-behave-rfc3489bis-15
  14  * - draft-ietf-mmusic-ice-19
  15  * - draft-ietf-behave-nat-behavior-discovery-03
  16  * - draft-ietf-behave-turn-07
  17  * - draft-ietf-behave-turn-ipv6-03
  18  *
  19  * XXX - these are now:
  20  * - RFC 5389
  21  * - RFC 5245
  22  * - RFC 5780
  23  * - RFC 5766
  24  * - RFC 6156
  25  *
  26  * Update as necessary.
  27  */
  28
  29 #include "config.h"
  30
  31 #include <epan/packet.h>
  32 #include "packet-tcp.h"
  33
  34 void proto_register_turnchannel(void);
  35 void proto_reg_handoff_turnchannel(void);
  36
  37 /* heuristic subdissectors */
  38 static heur_dissector_list_t heur_subdissector_list;
  39
  40 /* Initialize the protocol and registered fields */
  41 static int proto_turnchannel = -1;
  42
  43 static int hf_turnchannel_id = -1;
  44 static int hf_turnchannel_len = -1;
  45
  46 #define TURNCHANNEL_HDR_LEN     ((guint)4)
  47
  48
  49 /* Initialize the subtree pointers */
  50 static gint ett_turnchannel = -1;
  51
  52 static dissector_handle_t turnchannel_tcp_handle;
  53 static dissector_handle_t turnchannel_udp_handle;
  54
  55 static int
  56 dissect_turnchannel_message(tvbuff_t *tvb, packet_info *pinfo,
  57                             proto_tree *tree, void *data _U_)
  58 {
  59         guint   len;
  60         guint16 channel_id;
  61         guint16 data_len;
  62         proto_item *ti;
  63         proto_tree *turnchannel_tree;
  64         heur_dtbl_entry_t *hdtbl_entry;
  65
  66         len = tvb_captured_length(tvb);
  67         /* First, make sure we have enough data to do the check. */
  68         if (len < TURNCHANNEL_HDR_LEN) {
  69                   return 0;
  70         }
  71
  72         channel_id = tvb_get_ntohs(tvb, 0);
  73         data_len = tvb_get_ntohs(tvb, 2);
  74
  75         if ((channel_id < 0x4000) || (channel_id > 0xFFFE)) {
  76           return 0;
  77         }
  78
  79         if (len != TURNCHANNEL_HDR_LEN + data_len) {
  80           return 0;
  81         }
  82
  83         /* Seems to be a decent TURN channel message */
  84         col_set_str(pinfo->cinfo, COL_PROTOCOL, "TURN CHANNEL");
  85
  86         col_add_fstr(pinfo->cinfo, COL_INFO, "Channel Id 0x%x", channel_id);
  87
  88         ti = proto_tree_add_item(tree, proto_turnchannel, tvb, 0, -1, ENC_NA);
  89
  90         turnchannel_tree = proto_item_add_subtree(ti, ett_turnchannel);
  91
  92         proto_tree_add_uint(turnchannel_tree, hf_turnchannel_id, tvb, 0, 2, channel_id);
  93         proto_tree_add_uint(turnchannel_tree, hf_turnchannel_len, tvb, 2, 2, data_len);
  94
  95
  96         if (len > TURNCHANNEL_HDR_LEN) {
  97           tvbuff_t *next_tvb;
  98           guint reported_len, new_len;
  99
 100           new_len = tvb_captured_length_remaining(tvb, TURNCHANNEL_HDR_LEN);
 101           reported_len = tvb_reported_length_remaining(tvb,
 102                                                        TURNCHANNEL_HDR_LEN);
 103           if (data_len < reported_len) {
 104             reported_len = data_len;
 105           }
 106           next_tvb = tvb_new_subset_length_caplen(tvb, TURNCHANNEL_HDR_LEN, new_len,
 107                                     reported_len);
 108
 109
 110           if (!dissector_try_heuristic(heur_subdissector_list,
 111                                        next_tvb, pinfo, tree, &hdtbl_entry, NULL)) {
 112             call_data_dissector(next_tvb, pinfo, tree);
 113           }
 114         }
 115
 116         return tvb_captured_length(tvb);
 117 }
 118
 119 static guint
 120 get_turnchannel_message_len(packet_info *pinfo _U_, tvbuff_t *tvb,
 121                             int offset, void *data _U_)
 122 {
 123         return (guint)tvb_get_ntohs(tvb, offset+2) + TURNCHANNEL_HDR_LEN;
 124 }
 125
 126 static int
 127 dissect_turnchannel_tcp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data)
 128 {
 129         tcp_dissect_pdus(tvb, pinfo, tree, TRUE, TURNCHANNEL_HDR_LEN,
 130                         get_turnchannel_message_len, dissect_turnchannel_message, data);
 131         return tvb_captured_length(tvb);
 132 }
 133
 134
 135 static gboolean
 136 dissect_turnchannel_heur(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
 137 {
 138         guint   len;
 139         guint16 channel_id;
 140         guint16 data_len;
 141
 142         len = tvb_captured_length(tvb);
 143         /* First, make sure we have enough data to do the check. */
 144         if (len < TURNCHANNEL_HDR_LEN) {
 145                   return FALSE;
 146         }
 147
 148         channel_id = tvb_get_ntohs(tvb, 0);
 149         data_len = tvb_get_ntohs(tvb, 2);
 150
 151         if ((channel_id < 0x4000) || (channel_id > 0xFFFE)) {
 152           return FALSE;
 153         }
 154
 155         if (len != TURNCHANNEL_HDR_LEN + data_len) {
 156           return FALSE;
 157         }
 158
 159         return dissect_turnchannel_message(tvb, pinfo, tree, NULL);
 160 }
 161
 162 void
 163 proto_register_turnchannel(void)
 164 {
 165         static hf_register_info hf[] = {
 166                 { &hf_turnchannel_id,
 167                         { "TURN Channel ID",    "turnchannel.id",       FT_UINT16,
 168                         BASE_HEX,       NULL,   0x0,    NULL,   HFILL }
 169                 },
 170                 { &hf_turnchannel_len,
 171                         { "Data Length",  "turnchannel.length", FT_UINT16,
 172                         BASE_DEC,       NULL,   0x0,    NULL,   HFILL }
 173                 },
 174         };
 175
 176 /* Setup protocol subtree array */
 177         static gint *ett[] = {
 178                 &ett_turnchannel,
 179         };
 180
 181 /* Register the protocol name and description */
 182         proto_turnchannel = proto_register_protocol("TURN Channel",
 183             "TURNCHANNEL", "turnchannel");
 184
 185         turnchannel_tcp_handle = register_dissector("turnchannel-tcp", dissect_turnchannel_tcp, proto_turnchannel);
 186         turnchannel_udp_handle = register_dissector("turnchannel", dissect_turnchannel_message, proto_turnchannel);
 187
 188 /* subdissectors */
 189         heur_subdissector_list = register_heur_dissector_list("turnchannel", proto_turnchannel);
 190
 191 /* Required function calls to register the header fields and subtrees used */
 192         proto_register_field_array(proto_turnchannel, hf, array_length(hf));
 193         proto_register_subtree_array(ett, array_length(ett));
 194
 195 }
 196
 197
 198 void
 199 proto_reg_handoff_turnchannel(void)
 200 {
 201         /* Register for "Decode As" in case STUN negotiation isn't captured */
 202         dissector_add_for_decode_as_with_preference("tcp.port", turnchannel_tcp_handle);
 203         dissector_add_for_decode_as_with_preference("udp.port", turnchannel_udp_handle);
 204
 205         /*
 206          * SSL/TLS and DTLS Application-Layer Protocol Negotiation (ALPN)
 207          * protocol ID.
 208          */
 209         dissector_add_string("tls.alpn", "stun.turn", turnchannel_tcp_handle);
 210         dissector_add_string("dtls.alpn", "stun.turn", turnchannel_udp_handle);
 211
 212         /* TURN negotiation is handled through STUN2 dissector (packet-stun.c),
 213            so only it should be able to determine if a packet is a TURN packet */
 214         heur_dissector_add("stun", dissect_turnchannel_heur, "TURN Channel over STUN", "turnchannel_stun", proto_turnchannel, HEURISTIC_ENABLE);
 215 }
 216
 217 /*
 218  * Editor modelines  -  http://www.wireshark.org/tools/modelines.html
 219  *
 220  * Local variables:
 221  * c-basic-offset: 8
 222  * tab-width: 8
 223  * indent-tabs-mode: t
 224  * End:
 225  *
 226  * vi: set shiftwidth=8 tabstop=8 noexpandtab:
 227  * :indentSize=8:tabSize=8:noTabs=false:
 228  */