/* * packet-rtcdc.c * Routines for the RTCWeb Data Channel Protocol dissection * as specified in * http://tools.ietf.org/html/draft-jesup-rtcweb-data-protocol-03 * and specified in * http://tools.ietf.org/html/draft-ietf-rtcweb-data-protocol-08 * We might want to remove the support of * http://tools.ietf.org/html/draft-jesup-rtcweb-data-protocol-03 * in the future, but I'll leave it in for now. * Copyright 2012 - 2013, Michael Tuexen * * Wireshark - Network traffic analyzer * By Gerald Combs * Copyright 1998 Gerald Combs * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License along * with this program; if not, write to the Free Software Foundation, Inc., * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. */ #include "config.h" #include #include #include #include void proto_register_rtcdc(void); void proto_reg_handoff_rtcdc(void); /* PPID used for this protocol */ static guint32 rtcdc_ppid = WEBRTC_DCEP_PROTOCOL_ID; /* Initialize the protocol and registered fields */ static int proto_rtcdc = -1; static int hf_message_type = -1; static int hf_channel_type = -1; static int hf_flags = -1; static int hf_flags_reserved = -1; static int hf_unordered_allowed = -1; static int hf_reliability = -1; static int hf_priority = -1; static int hf_label = -1; static int hf_error = -1; static int hf_sid = -1; static int hf_new_channel_type = -1; static int hf_new_reliability = -1; static int hf_new_priority = -1; static int hf_new_label_length = -1; static int hf_new_protocol_length = -1; static int hf_new_label = -1; static int hf_new_protocol = -1; /* Initialize the subtree pointers */ static gint ett_rtcdc = -1; static gint ett_flags = -1; static expert_field ei_rtcdc_new_reliability_non_zero = EI_INIT; static expert_field ei_rtcdc_message_type_unknown = EI_INIT; static expert_field ei_rtcdc_inconsistent_label_and_parameter_length = EI_INIT; static expert_field ei_rtcdc_message_too_long = EI_INIT; static expert_field ei_rtcdc_new_channel_type = EI_INIT; #define DATA_CHANNEL_OPEN_REQUEST 0x00 #define DATA_CHANNEL_OPEN_RESPONSE 0x01 #define DATA_CHANNEL_ACK 0x02 #define DATA_CHANNEL_NEW_OPEN_REQUEST 0x03 static const value_string message_type_values[] = { { DATA_CHANNEL_OPEN_REQUEST, "DATA_CHANNEL_OPEN_REQUEST" }, { DATA_CHANNEL_OPEN_RESPONSE, "DATA_CHANNEL_OPEN_RESPONSE" }, { DATA_CHANNEL_ACK, "DATA_CHANNEL_ACK" }, { DATA_CHANNEL_NEW_OPEN_REQUEST, "DATA_CHANNEL_OPEN_REQUEST" }, { 0, NULL } }; #define DATA_CHANNEL_RELIABLE 0x00 #define DATA_CHANNEL_PARTIAL_RELIABLE_REXMIT 0x01 #define DATA_CHANNEL_PARTIAL_RELIABLE_TIMED 0x02 static const value_string channel_type_values[] = { { DATA_CHANNEL_RELIABLE, "DATA_CHANNEL_RELIABLE" }, { DATA_CHANNEL_PARTIAL_RELIABLE_REXMIT, "DATA_CHANNEL_PARTIAL_RELIABLE_REXMIT" }, { DATA_CHANNEL_PARTIAL_RELIABLE_TIMED, "DATA_CHANNEL_PARTIAL_RELIABLE_TIMED" }, { 0, NULL } }; #define MESSAGE_TYPE_LENGTH 1 #define CHANNEL_TYPE_LENGTH 1 #define FLAGS_LENGTH 2 #define RELIABILITY_LENGTH 2 #define PRIORITY_LENGTH 2 #define MESSAGE_TYPE_OFFSET 0 #define CHANNEL_TYPE_OFFSET (MESSAGE_TYPE_OFFSET + MESSAGE_TYPE_LENGTH) #define FLAGS_OFFSET (CHANNEL_TYPE_OFFSET + CHANNEL_TYPE_LENGTH) #define RELIABILITY_OFFSET (FLAGS_OFFSET + FLAGS_LENGTH) #define PRIORITY_OFFSET (RELIABILITY_OFFSET + RELIABILITY_LENGTH) #define LABEL_OFFSET (PRIORITY_OFFSET + PRIORITY_LENGTH) #define DATA_CHANNEL_FLAG_OUT_OF_ORDER_ALLOWED_MASK 0x0001 #define DATA_CHANNEL_FLAG_RESERVED_MASK 0xFFFE static void dissect_open_request_message(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *rtcdc_tree, proto_item *rtcdc_item _U_) { if (rtcdc_tree) { proto_tree *flags_tree; proto_item *flags_item; proto_tree_add_item(rtcdc_tree, hf_channel_type, tvb, CHANNEL_TYPE_OFFSET, CHANNEL_TYPE_LENGTH, ENC_BIG_ENDIAN); flags_item = proto_tree_add_item(rtcdc_tree, hf_flags, tvb, FLAGS_OFFSET, FLAGS_LENGTH, ENC_BIG_ENDIAN); flags_tree = proto_item_add_subtree(flags_item, ett_flags); proto_tree_add_item(flags_tree, hf_flags_reserved, tvb, FLAGS_OFFSET, FLAGS_LENGTH, ENC_BIG_ENDIAN); proto_tree_add_item(flags_tree, hf_unordered_allowed, tvb, FLAGS_OFFSET, FLAGS_LENGTH, ENC_BIG_ENDIAN); proto_tree_add_item(rtcdc_tree, hf_reliability, tvb, RELIABILITY_OFFSET, RELIABILITY_LENGTH, ENC_BIG_ENDIAN); proto_tree_add_item(rtcdc_tree, hf_priority, tvb, PRIORITY_OFFSET, PRIORITY_LENGTH, ENC_BIG_ENDIAN); proto_tree_add_item(rtcdc_tree, hf_label, tvb, LABEL_OFFSET, -1, ENC_ASCII|ENC_NA); } return; } #define ERROR_LENGTH 1 #define SID_LENGTH 2 #define DATA_CHANNEL_RESPONSE_LENGTH (MESSAGE_TYPE_LENGTH + ERROR_LENGTH + FLAGS_LENGTH + SID_LENGTH) #define ERROR_OFFSET (MESSAGE_TYPE_OFFSET + MESSAGE_TYPE_LENGTH) #define SID_OFFSET (FLAGS_OFFSET + FLAGS_LENGTH) static void dissect_open_response_message(tvbuff_t *tvb, packet_info *pinfo, proto_tree *rtcdc_tree, proto_item *rtcdc_item) { if (tvb_reported_length(tvb) > DATA_CHANNEL_RESPONSE_LENGTH) { expert_add_info(pinfo, rtcdc_item, &ei_rtcdc_message_too_long); } if (rtcdc_tree) { proto_tree_add_item(rtcdc_tree, hf_error, tvb, ERROR_OFFSET, ERROR_LENGTH, ENC_BIG_ENDIAN); proto_tree_add_item(rtcdc_tree, hf_flags, tvb, FLAGS_OFFSET, FLAGS_LENGTH, ENC_BIG_ENDIAN); proto_tree_add_item(rtcdc_tree, hf_sid, tvb, SID_OFFSET, SID_LENGTH, ENC_BIG_ENDIAN); } return; } #define DATA_CHANNEL_ACK_LENGTH MESSAGE_TYPE_LENGTH static void dissect_open_ack_message(tvbuff_t *tvb, packet_info *pinfo, proto_tree *rtcdc_tree _U_, proto_item *rtcdc_item) { if (tvb_reported_length(tvb) > DATA_CHANNEL_ACK_LENGTH) { expert_add_info(pinfo, rtcdc_item, &ei_rtcdc_message_too_long); } return; } #define NEW_DATA_CHANNEL_RELIABLE 0x00 #define NEW_DATA_CHANNEL_PARTIAL_RELIABLE_REXMIT 0x01 #define NEW_DATA_CHANNEL_PARTIAL_RELIABLE_TIMED 0x02 #define NEW_DATA_CHANNEL_RELIABLE_UNORDERED 0x80 #define NEW_DATA_CHANNEL_PARTIAL_RELIABLE_REXMIT_UNORDERED 0x81 #define NEW_DATA_CHANNEL_PARTIAL_RELIABLE_TIMED_UNORDERED 0x82 static const value_string new_channel_type_values[] = { { NEW_DATA_CHANNEL_RELIABLE, "DATA_CHANNEL_RELIABLE" }, { NEW_DATA_CHANNEL_PARTIAL_RELIABLE_REXMIT, "DATA_CHANNEL_PARTIAL_RELIABLE_REXMIT" }, { NEW_DATA_CHANNEL_PARTIAL_RELIABLE_TIMED, "DATA_CHANNEL_PARTIAL_RELIABLE_TIMED" }, { NEW_DATA_CHANNEL_RELIABLE_UNORDERED, "DATA_CHANNEL_RELIABLE_UNORDERED" }, { NEW_DATA_CHANNEL_PARTIAL_RELIABLE_REXMIT_UNORDERED, "DATA_CHANNEL_PARTIAL_RELIABLE_REXMIT_UNORDERED" }, { NEW_DATA_CHANNEL_PARTIAL_RELIABLE_TIMED_UNORDERED, "DATA_CHANNEL_PARTIAL_RELIABLE_TIMED_UNORDERED" }, { 0, NULL } }; #define NEW_MESSAGE_TYPE_LENGTH 1 #define NEW_CHANNEL_TYPE_LENGTH 1 #define NEW_PRIORITY_LENGTH 2 #define NEW_RELIABILITY_LENGTH 4 #define NEW_LABEL_LENGTH_LENGTH 2 #define NEW_PROTOCOL_LENGTH_LENGTH 2 #define NEW_OPEN_REQUEST_HEADER_LENGTH (guint)(NEW_MESSAGE_TYPE_LENGTH + \ NEW_CHANNEL_TYPE_LENGTH + \ NEW_PRIORITY_LENGTH + \ NEW_RELIABILITY_LENGTH + \ NEW_LABEL_LENGTH_LENGTH + \ NEW_PROTOCOL_LENGTH_LENGTH) #define NEW_MESSAGE_TYPE_OFFSET 0 #define NEW_CHANNEL_TYPE_OFFSET (NEW_MESSAGE_TYPE_OFFSET + NEW_MESSAGE_TYPE_LENGTH) #define NEW_PRIORITY_OFFSET (NEW_CHANNEL_TYPE_OFFSET + NEW_CHANNEL_TYPE_LENGTH) #define NEW_RELIABILITY_OFFSET (NEW_PRIORITY_OFFSET + NEW_PRIORITY_LENGTH) #define NEW_LABEL_LENGTH_OFFSET (NEW_RELIABILITY_OFFSET + NEW_RELIABILITY_LENGTH) #define NEW_PROTOCOL_LENGTH_OFFSET (NEW_LABEL_LENGTH_OFFSET + NEW_LABEL_LENGTH_LENGTH) #define NEW_LABEL_OFFSET (NEW_PROTOCOL_LENGTH_OFFSET + NEW_PROTOCOL_LENGTH_LENGTH) static void dissect_new_open_request_message(tvbuff_t *tvb, packet_info *pinfo, proto_tree *rtcdc_tree, proto_item *rtcdc_item) { guint8 channel_type; guint32 reliability; guint16 label_length; guint16 protocol_length; channel_type = tvb_get_guint8(tvb, NEW_CHANNEL_TYPE_OFFSET); if ((channel_type & 0x7f) > 0x02) { expert_add_info(pinfo, rtcdc_item, &ei_rtcdc_new_channel_type); } reliability = tvb_get_ntohl(tvb, NEW_RELIABILITY_OFFSET); if ((reliability > 0) && ((channel_type & 0x7f) == 0x00)) { expert_add_info(pinfo, rtcdc_item, &ei_rtcdc_new_reliability_non_zero); } label_length = tvb_get_ntohs(tvb, NEW_LABEL_LENGTH_OFFSET); protocol_length = tvb_get_ntohs(tvb, NEW_PROTOCOL_LENGTH_OFFSET); if (NEW_OPEN_REQUEST_HEADER_LENGTH + (guint)label_length + (guint)protocol_length != tvb_reported_length(tvb)) { expert_add_info(pinfo, rtcdc_item, &ei_rtcdc_inconsistent_label_and_parameter_length); } if (rtcdc_tree) { proto_tree_add_item(rtcdc_tree, hf_new_channel_type, tvb, NEW_CHANNEL_TYPE_OFFSET, NEW_CHANNEL_TYPE_LENGTH, ENC_BIG_ENDIAN); proto_tree_add_item(rtcdc_tree, hf_new_priority, tvb, NEW_PRIORITY_OFFSET, NEW_PRIORITY_LENGTH, ENC_BIG_ENDIAN); proto_tree_add_item(rtcdc_tree, hf_new_reliability, tvb, NEW_RELIABILITY_OFFSET, NEW_RELIABILITY_LENGTH, ENC_BIG_ENDIAN); proto_tree_add_item(rtcdc_tree, hf_new_label_length, tvb, NEW_LABEL_LENGTH_OFFSET, NEW_LABEL_LENGTH_LENGTH, ENC_BIG_ENDIAN); proto_tree_add_item(rtcdc_tree, hf_new_protocol_length, tvb, NEW_PROTOCOL_LENGTH_OFFSET, NEW_PROTOCOL_LENGTH_LENGTH, ENC_BIG_ENDIAN); proto_tree_add_item(rtcdc_tree, hf_new_label, tvb, NEW_LABEL_OFFSET, label_length, ENC_ASCII|ENC_NA); proto_tree_add_item(rtcdc_tree, hf_new_protocol, tvb, NEW_LABEL_OFFSET + label_length, protocol_length, ENC_ASCII|ENC_NA); } return; } static int dissect_rtcdc(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_) { proto_item *rtcdc_item, *msg_item; proto_tree *rtcdc_tree; guint8 message_type; message_type = tvb_get_guint8(tvb, MESSAGE_TYPE_OFFSET); col_set_str(pinfo->cinfo, COL_PROTOCOL, "RTCDC"); col_add_fstr(pinfo->cinfo, COL_INFO, "%s ", val_to_str_const(message_type, message_type_values, "reserved")); rtcdc_item = proto_tree_add_item(tree, proto_rtcdc, tvb, 0, -1, ENC_NA); rtcdc_tree = proto_item_add_subtree(rtcdc_item, ett_rtcdc); msg_item = proto_tree_add_item(rtcdc_tree, hf_message_type, tvb, MESSAGE_TYPE_OFFSET, MESSAGE_TYPE_LENGTH, ENC_BIG_ENDIAN); switch (message_type) { case DATA_CHANNEL_OPEN_REQUEST: dissect_open_request_message(tvb, pinfo, rtcdc_tree, rtcdc_item); break; case DATA_CHANNEL_OPEN_RESPONSE: dissect_open_response_message(tvb, pinfo, rtcdc_tree, rtcdc_item); break; case DATA_CHANNEL_ACK: dissect_open_ack_message(tvb, pinfo, rtcdc_tree, rtcdc_item); break; case DATA_CHANNEL_NEW_OPEN_REQUEST: dissect_new_open_request_message(tvb, pinfo, rtcdc_tree, rtcdc_item); break; default: expert_add_info(pinfo, msg_item, &ei_rtcdc_message_type_unknown); break; } return tvb_captured_length(tvb); } void proto_register_rtcdc(void) { module_t *rtcdc_module; expert_module_t *expert_rtcdc; static hf_register_info hf[] = { { &hf_message_type, { "Message type", "rtcdc.message_type", FT_UINT8, BASE_DEC, VALS(message_type_values), 0x0, NULL, HFILL } }, { &hf_channel_type, { "Channel type", "rtcdc.channel_type", FT_UINT8, BASE_DEC, VALS(channel_type_values), 0x0, NULL, HFILL } }, { &hf_flags, { "Flags", "rtcdc.flags", FT_UINT16, BASE_HEX, NULL, 0x0, NULL, HFILL } }, { &hf_flags_reserved, { "Reserved", "rtcdc.flags_reserved", FT_UINT16, BASE_HEX, NULL, DATA_CHANNEL_FLAG_RESERVED_MASK, NULL, HFILL } }, { &hf_unordered_allowed, { "Unordered allowed", "rtcdc.flags_unordered_allowed", FT_BOOLEAN, 16, NULL, DATA_CHANNEL_FLAG_OUT_OF_ORDER_ALLOWED_MASK, NULL, HFILL } }, { &hf_reliability, { "Reliability parameter", "rtcdc.reliability_parameter", FT_UINT16, BASE_DEC, NULL, 0x0, NULL, HFILL } }, { &hf_priority, { "Priority", "rtcdc.priority", FT_UINT16, BASE_DEC, NULL, 0x0, NULL, HFILL } }, { &hf_label, { "Label", "rtcdc.label", FT_STRING, BASE_NONE, NULL, 0x0, NULL, HFILL } }, { &hf_error, { "Error", "rtcdc.error", FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL } }, { &hf_sid, { "Reverse stream identifier", "rtcdc.reverse_stream_id", FT_UINT16, BASE_DEC, NULL, 0x0, NULL, HFILL } }, { &hf_new_channel_type, { "Channel type", "rtcdc.channel_type", FT_UINT8, BASE_DEC, VALS(new_channel_type_values), 0x0, NULL, HFILL } }, { &hf_new_reliability, { "Reliability parameter", "rtcdc.reliability_parameter", FT_UINT32, BASE_DEC, NULL, 0x0, NULL, HFILL } }, { &hf_new_priority, { "Priority", "rtcdc.priority", FT_UINT16, BASE_DEC, NULL, 0x0, NULL, HFILL } }, { &hf_new_label_length, { "Label length", "rtcdc.label_length", FT_UINT16, BASE_DEC, NULL, 0x0, NULL, HFILL } }, { &hf_new_protocol_length, { "Protocol length", "rtcdc.protocol_length", FT_UINT16, BASE_DEC, NULL, 0x0, NULL, HFILL } }, { &hf_new_label, { "Label", "rtcdc.label", FT_STRING, BASE_NONE, NULL, 0x0, NULL, HFILL } }, { &hf_new_protocol, { "Protocol", "rtcdc.protocol", FT_STRING, BASE_NONE, NULL, 0x0, NULL, HFILL } } }; static gint *ett[] = { &ett_rtcdc, &ett_flags }; static ei_register_info ei[] = { { &ei_rtcdc_message_too_long, { "rtcdc.message_too_long", PI_MALFORMED, PI_ERROR, "Message too long", EXPFILL }}, { &ei_rtcdc_new_channel_type, { "rtcdc.channel_type.unknown", PI_PROTOCOL, PI_WARN, "Unknown channel type", EXPFILL }}, { &ei_rtcdc_new_reliability_non_zero, { "rtcdc.reliability_parameter.non_zero", PI_PROTOCOL, PI_WARN, "Reliability parameter non zero for reliable channel", EXPFILL }}, { &ei_rtcdc_inconsistent_label_and_parameter_length, { "rtcdc.inconsistent_label_and_parameter_length", PI_MALFORMED, PI_ERROR, "Inconsistent label and parameter length", EXPFILL }}, { &ei_rtcdc_message_type_unknown, { "rtcdc.message_type.unknown", PI_PROTOCOL, PI_WARN, "Unknown message type", EXPFILL }}, }; proto_rtcdc = proto_register_protocol("WebRTC Datachannel Protocol", "RTCDC", "rtcdc"); proto_register_field_array(proto_rtcdc, hf, array_length(hf)); proto_register_subtree_array(ett, array_length(ett)); expert_rtcdc = expert_register_protocol(proto_rtcdc); expert_register_field_array(expert_rtcdc, ei, array_length(ei)); rtcdc_module = prefs_register_protocol(proto_rtcdc, proto_reg_handoff_rtcdc); prefs_register_uint_preference(rtcdc_module, "sctp.ppi", "RTCDC SCTP PPID", "RTCDC SCTP PPID if other than the default", 10, &rtcdc_ppid); } void proto_reg_handoff_rtcdc(void) { static gboolean initialized = FALSE; static dissector_handle_t rtcdc_handle; static guint32 current_ppid; if (!initialized) { rtcdc_handle = create_dissector_handle(dissect_rtcdc, proto_rtcdc); initialized = TRUE; } else { dissector_delete_uint("sctp.ppi", current_ppid, rtcdc_handle); } current_ppid = rtcdc_ppid; dissector_add_uint("sctp.ppi", current_ppid, rtcdc_handle); } /* * Editor modelines - http://www.wireshark.org/tools/modelines.html * * Local variables: * c-basic-offset: 4 * tab-width: 8 * indent-tabs-mode: nil * End: * * vi: set shiftwidth=4 tabstop=8 expandtab: * :indentSize=4:tabSize=8:noTabs=true: */