/* packet-t38.c * Routines for T.38 packet dissection * 2003 Hans Viens * * $Id: packet-t38.c,v 1.7 2004/05/24 02:25:19 guy Exp $ * * Ethereal - 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ /* Depending on what ASN.1 specification is used you may have to change * the preference setting regarding Pre-Corrigendum ASN.1 specification: * http://www.itu.int/ITU-T/asn1/database/itu-t/t/t38/1998/T38.html (Pre-Corrigendum=TRUE) * http://www.itu.int/ITU-T/asn1/database/itu-t/t/t38/2003/T38(1998).html (Pre-Corrigendum=TRUE) * * http://www.itu.int/ITU-T/asn1/database/itu-t/t/t38/2003/T38(2002).html (Pre-Corrigendum=FALSE) * http://www.itu.int/ITU-T/asn1/database/itu-t/t/t38/2002/t38.html (Pre-Corrigendum=FALSE) * http://www.itu.int/ITU-T/asn1/database/itu-t/t/t38/2002-Amd1/T38.html (Pre-Corrigendum=FALSE) */ /* TO DO: * - TCP desegmentation is currently not supported for T.38 IFP directly over TCP. * - SDP and H.245 dissectors should be updated to start conversations for T.38 similar to RTP. * - It would be nice if we could dissect the T.30 data. * - Sometimes the last octet is not high-lighted when selecting something in the tree. Bug in PER dissector? * - Add support for RTP payload audio/t38 (draft-jones-avt-audio-t38-03.txt), i.e. T38 in RTP packets. */ #ifdef HAVE_CONFIG_H # include "config.h" #endif #include #include #include #include #include #include "prefs.h" #include "ipproto.h" #include "packet-per.h" #include "prefs.h" #include "packet-tpkt.h" #define PORT_T38 6004 static guint global_t38_tcp_port = PORT_T38; static guint global_t38_udp_port = PORT_T38; /* * Variables to allow for proper deletion of dissector registration when * the user changes port from the gui. */ static guint tcp_port = 0; static guint udp_port = 0; /* dissect using the Pre Corrigendum T.38 ASN.1 specification (1998) */ static gboolean use_pre_corrigendum_asn1_specification = TRUE; /* dissect packets that looks like RTP version 2 packets as RTP */ /* instead of as T.38. This may result in that some T.38 UPTL */ /* packets with sequence number values higher than 32767 may be */ /* shown as RTP packets. */ static gboolean dissect_possible_rtpv2_packets_as_rtp = FALSE; /* Reassembly of T.38 PDUs over TPKT over TCP */ static gboolean t38_tpkt_reassembly = TRUE; /* Preference setting whether TPKT header is used when sending T.38 over TCP. * The default setting is Maybe where the dissector will look on the first * bytes to try to determine whether TPKT header is used or not. This may not * work so well in some cases. You may want to change the setting to Always or * Newer. */ #define T38_TPKT_NEVER 0 /* Assume that there is never a TPKT header */ #define T38_TPKT_ALWAYS 1 /* Assume that there is always a TPKT header */ #define T38_TPKT_MAYBE 2 /* Assume TPKT if first octets are 03-00-xx-xx */ static gint t38_tpkt_usage = T38_TPKT_MAYBE; static const enum_val_t t38_tpkt_options[] = { {"never", "Never", T38_TPKT_NEVER}, {"always", "Always", T38_TPKT_ALWAYS}, {"maybe", "Maybe", T38_TPKT_MAYBE}, {NULL, NULL, -1} }; static dissector_handle_t t38_udp_handle; static dissector_handle_t t38_tcp_handle; static dissector_handle_t t38_tcp_pdu_handle; static dissector_handle_t rtp_handle; static guint32 Type_of_msg_value; static guint32 Data_Field_field_type_value; static guint32 Data_value; static guint32 T30ind_value; static int proto_t38 = -1; static int hf_t38_IFPPacket = -1; static int hf_t38_Type_of_msg = -1; static int hf_t38_t30_indicator = -1; static int hf_t38_data = -1; static int hf_t38_Data_Field = -1; static int hf_t38_Data_Field_item = -1; static int hf_t38_Data_Field_field_type = -1; static int hf_t38_Data_Field_field_data = -1; static int hf_t38_UDPTLPacket = -1; static int hf_t38_seq_number = -1; static int hf_t38_primary_ifp_packet = -1; static int hf_t38_primary_ifp_packet_length = -1; static int hf_t38_error_recovery = -1; static int hf_t38_secondary_ifp_packets = -1; static int hf_t38_secondary_ifp_packets_item = -1; static int hf_t38_secondary_ifp_packets_item_length = -1; static int hf_t38_fec_info = -1; static int hf_t38_fec_npackets = -1; static int hf_t38_fec_data = -1; static int hf_t38_fec_data_item = -1; static gint ett_t38 = -1; static gint ett_t38_IFPPacket = -1; static gint ett_t38_Type_of_msg = -1; static gint ett_t38_t30_indicator = -1; static gint ett_t38_data = -1; static gint ett_t38_Data_Field = -1; static gint ett_t38_Data_Field_item = -1; static gint ett_t38_Data_Field_field_type = -1; static gint ett_t38_UDPTLPacket = -1; static gint ett_t38_error_recovery = -1; static gint ett_t38_secondary_ifp_packets = -1; static gint ett_t38_fec_info = -1; static gint ett_t38_fec_data = -1; static gboolean primary_part = TRUE; static guint32 seq_number = 0; /* RTP Version is the first 2 bits of the first octet in the UDP payload*/ #define RTP_VERSION(octet) ((octet) >> 6) void proto_reg_handoff_t38(void); static int dissect_t38_NULL(tvbuff_t *tvb _U_, int offset, packet_info *pinfo _U_, proto_tree *tree _U_) { return offset; } static per_choice_t t30_indicator_choice[] = { { 0, "no-signal", ASN1_EXTENSION_ROOT, dissect_t38_NULL}, { 1, "cng", ASN1_EXTENSION_ROOT, dissect_t38_NULL}, { 2, "ced", ASN1_EXTENSION_ROOT, dissect_t38_NULL}, { 3, "v21-preamble", ASN1_EXTENSION_ROOT, dissect_t38_NULL}, { 4, "v27-2400-training", ASN1_EXTENSION_ROOT, dissect_t38_NULL}, { 5, "v27-4800-training", ASN1_EXTENSION_ROOT, dissect_t38_NULL}, { 6, "v29-7200-training", ASN1_EXTENSION_ROOT, dissect_t38_NULL}, { 7, "v29-9600-training", ASN1_EXTENSION_ROOT, dissect_t38_NULL}, { 8, "v17-7200-short-training", ASN1_EXTENSION_ROOT, dissect_t38_NULL}, { 9, "v17-7200-long-training", ASN1_EXTENSION_ROOT, dissect_t38_NULL}, { 10, "v17-9600-short-training", ASN1_EXTENSION_ROOT, dissect_t38_NULL}, { 11, "v17-9600-long-training", ASN1_EXTENSION_ROOT, dissect_t38_NULL}, { 12, "v17-12000-short-training", ASN1_EXTENSION_ROOT, dissect_t38_NULL}, { 13, "v17-12000-long-training", ASN1_EXTENSION_ROOT, dissect_t38_NULL}, { 14, "v17-14400-short-training", ASN1_EXTENSION_ROOT, dissect_t38_NULL}, { 15, "v17-14400-long-training", ASN1_EXTENSION_ROOT, dissect_t38_NULL}, { 16, "v8-ansam", ASN1_NOT_EXTENSION_ROOT, dissect_t38_NULL}, { 17, "v8-signal", ASN1_NOT_EXTENSION_ROOT, dissect_t38_NULL}, { 18, "v34-cntl-channel-1200", ASN1_NOT_EXTENSION_ROOT, dissect_t38_NULL}, { 19, "v34-pri-channel", ASN1_NOT_EXTENSION_ROOT, dissect_t38_NULL}, { 20, "v34-CC-retrain", ASN1_NOT_EXTENSION_ROOT, dissect_t38_NULL}, { 21, "v33-12000-training", ASN1_NOT_EXTENSION_ROOT, dissect_t38_NULL}, { 22, "v33-14400-training", ASN1_NOT_EXTENSION_ROOT, dissect_t38_NULL}, { 0, NULL, 0, NULL } }; static const value_string t30_indicator_vals[] = { { 0, "no-signal" }, { 1, "cng" }, { 2, "ced" }, { 3, "v21-preamble" }, { 4, "v27-2400-training" }, { 5, "v27-4800-training" }, { 6, "v29-7200-training" }, { 7, "v29-9600-training" }, { 8, "v17-7200-short-training" }, { 9, "v17-7200-long-training" }, { 10, "v17-9600-short-training" }, { 11, "v17-9600-long-training" }, { 12, "v17-12000-short-training" }, { 13, "v17-12000-long-training" }, { 14, "v17-14400-short-training" }, { 15, "v17-14400-long-training" }, { 16, "v8-ansam" }, { 17, "v8-signal" }, { 18, "v34-cntl-channel-1200" }, { 19, "v34-pri-channel" }, { 20, "v34-CC-retrain" }, { 21, "v33-12000-training" }, { 22, "v33-14400-training" }, { 0, NULL }, }; static int dissect_t38_t30_indicator(tvbuff_t *tvb, int offset, packet_info *pinfo, proto_tree *tree) { offset=dissect_per_choice(tvb, offset, pinfo, tree, hf_t38_t30_indicator, ett_t38_t30_indicator, t30_indicator_choice, "T30 Indicator", &T30ind_value); if (check_col(pinfo->cinfo, COL_INFO) && primary_part){ col_append_fstr(pinfo->cinfo, COL_INFO, " t30ind: %s", val_to_str(T30ind_value,t30_indicator_vals,"")); } return offset; } static per_choice_t data_choice[] = { { 0, "v21", ASN1_EXTENSION_ROOT, dissect_t38_NULL}, { 1, "v27-2400", ASN1_EXTENSION_ROOT, dissect_t38_NULL}, { 2, "v27-4800", ASN1_EXTENSION_ROOT, dissect_t38_NULL}, { 3, "v29-7200", ASN1_EXTENSION_ROOT, dissect_t38_NULL}, { 4, "v29-9600", ASN1_EXTENSION_ROOT, dissect_t38_NULL}, { 5, "v17-7200", ASN1_EXTENSION_ROOT, dissect_t38_NULL}, { 6, "v17-9600", ASN1_EXTENSION_ROOT, dissect_t38_NULL}, { 7, "v17-12000", ASN1_EXTENSION_ROOT, dissect_t38_NULL}, { 8, "v17-14400", ASN1_EXTENSION_ROOT, dissect_t38_NULL}, { 9, "v8", ASN1_NOT_EXTENSION_ROOT, dissect_t38_NULL}, { 10, "v34-pri-rate", ASN1_NOT_EXTENSION_ROOT, dissect_t38_NULL}, { 11, "v34-CC-1200", ASN1_NOT_EXTENSION_ROOT, dissect_t38_NULL}, { 12, "v34-pri-ch", ASN1_NOT_EXTENSION_ROOT, dissect_t38_NULL}, { 13, "v33-12000", ASN1_NOT_EXTENSION_ROOT, dissect_t38_NULL}, { 14, "v33-14400", ASN1_NOT_EXTENSION_ROOT, dissect_t38_NULL}, { 0, NULL, 0, NULL } }; static const value_string data_vals[] = { { 0, "v21" }, { 1, "v27-2400" }, { 2, "v27-4800" }, { 3, "v29-7200" }, { 4, "v29-9600" }, { 5, "v17-7200" }, { 6, "v17-9600" }, { 7, "v17-12000" }, { 8, "v17-14400" }, { 9, "v8" }, { 10, "v34-pri-rate" }, { 11, "v34-CC-1200" }, { 12, "v34-pri-ch" }, { 13, "v33-12000" }, { 14, "v33-14400" }, { 0, NULL }, }; static int dissect_t38_data(tvbuff_t *tvb, int offset, packet_info *pinfo, proto_tree *tree) { offset=dissect_per_choice(tvb, offset, pinfo, tree, hf_t38_data, ett_t38_data, data_choice, "data", &Data_value); if (check_col(pinfo->cinfo, COL_INFO) && primary_part){ col_append_fstr(pinfo->cinfo, COL_INFO, " data:%s:", val_to_str(Data_value,data_vals,"")); } return offset; } static per_choice_t Type_of_msg_choice[] = { { 0, "t30-indicator", ASN1_NO_EXTENSIONS, dissect_t38_t30_indicator}, { 1, "data", ASN1_NO_EXTENSIONS, dissect_t38_data}, { 0, NULL, 0, NULL } }; static const value_string Type_of_msg_vals[] = { { 0, "t30-indicator" }, { 1, "data" }, { 0, NULL} }; static int dissect_t38_Type_of_msg(tvbuff_t *tvb, int offset, packet_info *pinfo, proto_tree *tree) { offset=dissect_per_choice(tvb, offset, pinfo, tree, hf_t38_Type_of_msg, ett_t38_Type_of_msg, Type_of_msg_choice, "Type of message", &Type_of_msg_value); return offset; } static per_choice_t Data_Field_field_type_PreCorrigendum_choice[] = { { 0, "hdlc-data", ASN1_NO_EXTENSIONS, dissect_t38_NULL}, { 1, "hdlc-sig-end", ASN1_NO_EXTENSIONS, dissect_t38_NULL}, { 2, "hdlc-fcs-OK", ASN1_NO_EXTENSIONS, dissect_t38_NULL}, { 3, "hdlc-fcs-BAD", ASN1_NO_EXTENSIONS, dissect_t38_NULL}, { 4, "hdlc-fcs-OK-sig-end", ASN1_NO_EXTENSIONS, dissect_t38_NULL}, { 5, "hdlc-fcs-BAD-sig-end", ASN1_NO_EXTENSIONS, dissect_t38_NULL}, { 6, "t4-non-ecm-data", ASN1_NO_EXTENSIONS, dissect_t38_NULL}, { 7, "t4-non-ecm-sig-end", ASN1_NO_EXTENSIONS, dissect_t38_NULL}, { 0, NULL, 0, NULL } }; static per_choice_t Data_Field_field_type_choice[] = { { 0, "hdlc-data", ASN1_EXTENSION_ROOT, dissect_t38_NULL}, { 1, "hdlc-sig-end", ASN1_EXTENSION_ROOT, dissect_t38_NULL}, { 2, "hdlc-fcs-OK", ASN1_EXTENSION_ROOT, dissect_t38_NULL}, { 3, "hdlc-fcs-BAD", ASN1_EXTENSION_ROOT, dissect_t38_NULL}, { 4, "hdlc-fcs-OK-sig-end", ASN1_EXTENSION_ROOT, dissect_t38_NULL}, { 5, "hdlc-fcs-BAD-sig-end", ASN1_EXTENSION_ROOT, dissect_t38_NULL}, { 6, "t4-non-ecm-data", ASN1_EXTENSION_ROOT, dissect_t38_NULL}, { 7, "t4-non-ecm-sig-end", ASN1_EXTENSION_ROOT, dissect_t38_NULL}, { 8, "cm-message", ASN1_NOT_EXTENSION_ROOT, dissect_t38_NULL}, { 9, "jm-message", ASN1_NOT_EXTENSION_ROOT, dissect_t38_NULL}, { 10, "ci-message", ASN1_NOT_EXTENSION_ROOT, dissect_t38_NULL}, { 11, "v34-rate", ASN1_NOT_EXTENSION_ROOT, dissect_t38_NULL}, { 0, NULL, 0, NULL } }; static const value_string Data_Field_field_type_vals[] = { { 0, "hdlc-data" }, { 1, "hdlc-sig-end" }, { 2, "hdlc-fcs-OK" }, { 3, "hdlc-fcs-BAD" }, { 4, "hdlc-fcs-OK-sig-end" }, { 5, "hdlc-fcs-BAD-sig-end" }, { 6, "t4-non-ecm-data" }, { 7, "t4-non-ecm-sig-end" }, { 8, "cm-message" }, { 9, "jm-message" }, { 10, "ci-message" }, { 11, "v34-rate" }, { 0, NULL }, }; static int dissect_t38_Data_Field_field_type(tvbuff_t *tvb, int offset, packet_info *pinfo, proto_tree *tree) { if(use_pre_corrigendum_asn1_specification){ offset=dissect_per_choice(tvb, offset, pinfo, tree, hf_t38_Data_Field_field_type, ett_t38_Data_Field_field_type, Data_Field_field_type_PreCorrigendum_choice, "Field Type", &Data_Field_field_type_value); } else{ offset=dissect_per_choice(tvb, offset, pinfo, tree, hf_t38_Data_Field_field_type, ett_t38_Data_Field_field_type, Data_Field_field_type_choice, "Field Type", &Data_Field_field_type_value); } if (check_col(pinfo->cinfo, COL_INFO) && primary_part){ col_append_fstr(pinfo->cinfo, COL_INFO, " %s", val_to_str(Data_Field_field_type_value,Data_Field_field_type_vals,"")); } return offset; } static int dissect_t38_Data_Field_field_data(tvbuff_t *tvb, int offset, packet_info *pinfo, proto_tree *tree) { guint32 value_offset = 0; guint32 value_len = 0; offset=dissect_per_octet_string(tvb, offset, pinfo, tree, hf_t38_Data_Field_field_data, 1, 65535, &value_offset, &value_len); if (check_col(pinfo->cinfo, COL_INFO) && primary_part){ if(value_len < 8){ col_append_fstr(pinfo->cinfo, COL_INFO, "[%s]", tvb_bytes_to_str(tvb,value_offset,value_len)); } else { col_append_fstr(pinfo->cinfo, COL_INFO, "[%s...]", tvb_bytes_to_str(tvb,value_offset,7)); } } return offset; } static per_sequence_t Data_Field_item_sequence[] = { { "field-type", ASN1_NO_EXTENSIONS, ASN1_NOT_OPTIONAL, dissect_t38_Data_Field_field_type }, { "field-data", ASN1_NO_EXTENSIONS, ASN1_OPTIONAL, dissect_t38_Data_Field_field_data }, { NULL, 0, 0, NULL } }; static int dissect_t38_Data_Field_item(tvbuff_t *tvb, int offset, packet_info *pinfo, proto_tree *tree) { offset=dissect_per_sequence(tvb, offset, pinfo, tree, hf_t38_Data_Field_item, ett_t38_Data_Field_item, Data_Field_item_sequence); return offset; } static int dissect_t38_Data_Field(tvbuff_t *tvb, int offset, packet_info *pinfo, proto_tree *tree) { offset=dissect_per_sequence_of(tvb, offset, pinfo, tree, hf_t38_Data_Field, ett_t38_Data_Field, dissect_t38_Data_Field_item); return offset; } static per_sequence_t IFPPacket_sequence[] = { { "type-of-msg", ASN1_NO_EXTENSIONS, ASN1_NOT_OPTIONAL, dissect_t38_Type_of_msg }, { "data-field", ASN1_NO_EXTENSIONS, ASN1_OPTIONAL, dissect_t38_Data_Field }, { NULL, 0, 0, NULL } }; static int dissect_t38_IFPPacket(tvbuff_t *tvb, int offset, packet_info *pinfo, proto_tree *tree) { offset=dissect_per_sequence(tvb, offset, pinfo, tree, hf_t38_IFPPacket, ett_t38_IFPPacket, IFPPacket_sequence); return offset; } static int dissect_t38_seq_number(tvbuff_t *tvb, int offset, packet_info *pinfo, proto_tree *tree) { offset=dissect_per_constrained_integer(tvb, offset, pinfo, tree, hf_t38_seq_number, 0, 65535, &seq_number, NULL, FALSE); if (check_col(pinfo->cinfo, COL_INFO)){ col_append_fstr(pinfo->cinfo, COL_INFO, "Seq=%05u ",seq_number); } return offset; } static int dissect_t38_primary_ifp_packet(tvbuff_t *tvb, int offset, packet_info *pinfo, proto_tree *tree) { guint32 length; primary_part = TRUE; offset=dissect_per_length_determinant(tvb, offset, pinfo, tree, hf_t38_primary_ifp_packet_length, &length); offset=dissect_t38_IFPPacket(tvb, offset, pinfo, tree); return offset; } static int dissect_t38_secondary_ifp_packets_item(tvbuff_t *tvb, int offset, packet_info *pinfo, proto_tree *tree) { guint32 length; offset=dissect_per_length_determinant(tvb, offset, pinfo, tree, hf_t38_secondary_ifp_packets_item_length, &length); offset=dissect_t38_IFPPacket(tvb, offset, pinfo, tree); return offset; } static int dissect_t38_secondary_ifp_packets(tvbuff_t *tvb, int offset, packet_info *pinfo, proto_tree *tree) { /* When the field-data is not present, we MUST offset 1 byte*/ if((Data_Field_field_type_value != 0) && (Data_Field_field_type_value != 6)) { offset=offset+8; } offset=dissect_per_sequence_of(tvb, offset, pinfo, tree, hf_t38_secondary_ifp_packets, ett_t38_secondary_ifp_packets, dissect_t38_secondary_ifp_packets_item); return offset; } static int dissect_t38_fec_npackets(tvbuff_t *tvb, int offset, packet_info *pinfo, proto_tree *tree) { offset=dissect_per_integer(tvb, offset, pinfo, tree, hf_t38_fec_npackets, NULL, NULL); return offset; } static int dissect_t38_fec_data_item(tvbuff_t *tvb, int offset, packet_info *pinfo, proto_tree *tree) { offset=dissect_per_octet_string(tvb, offset, pinfo, tree, hf_t38_fec_data_item, -1, -1, NULL, NULL); return offset; } static int dissect_t38_fec_data(tvbuff_t *tvb, int offset, packet_info *pinfo, proto_tree *tree) { offset=dissect_per_sequence_of(tvb, offset, pinfo, tree, hf_t38_fec_data, ett_t38_fec_data, dissect_t38_fec_data_item); return offset; } static per_sequence_t fec_info_sequence[] = { { "fec-npackets", ASN1_NO_EXTENSIONS, ASN1_NOT_OPTIONAL, dissect_t38_fec_npackets }, { "fec-data", ASN1_NO_EXTENSIONS, ASN1_NOT_OPTIONAL, dissect_t38_fec_data }, { NULL, 0, 0, NULL } }; static int dissect_t38_fec_info(tvbuff_t *tvb, int offset, packet_info *pinfo, proto_tree *tree) { offset=dissect_per_sequence(tvb, offset, pinfo, tree, hf_t38_fec_info, ett_t38_fec_info, fec_info_sequence); return offset; } static per_choice_t error_recovery_choice[] = { { 0, "secondary-ifp-packets", ASN1_NO_EXTENSIONS, dissect_t38_secondary_ifp_packets}, { 1, "fec-info", ASN1_NO_EXTENSIONS, dissect_t38_fec_info}, { 0, NULL, 0, NULL } }; static const value_string error_recovery_vals[] = { { 0, "secondary-ifp-packets" }, { 1, "fec-info" }, { 0, NULL} }; static int dissect_t38_error_recovery(tvbuff_t *tvb, int offset, packet_info *pinfo, proto_tree *tree) { primary_part = FALSE; offset=dissect_per_choice(tvb, offset, pinfo, tree, hf_t38_error_recovery, ett_t38_error_recovery, error_recovery_choice, "Error recovery", NULL); primary_part = TRUE; return offset; } static per_sequence_t UDPTLPacket_sequence[] = { { "seq-number", ASN1_NO_EXTENSIONS, ASN1_NOT_OPTIONAL, dissect_t38_seq_number }, { "primary-ifp-packet", ASN1_NO_EXTENSIONS, ASN1_NOT_OPTIONAL, dissect_t38_primary_ifp_packet }, { "error-recovery", ASN1_NO_EXTENSIONS, ASN1_NOT_OPTIONAL, dissect_t38_error_recovery }, { NULL, 0, 0, NULL } }; static int dissect_t38_UDPTLPacket(tvbuff_t *tvb, int offset, packet_info *pinfo, proto_tree *tree) { /* Initialize to something else than data type */ Data_Field_field_type_value = 1; offset=dissect_per_sequence(tvb, offset, pinfo, tree, hf_t38_UDPTLPacket, ett_t38_UDPTLPacket, UDPTLPacket_sequence); return offset; } /* Entry point for dissection */ static void dissect_t38_udp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) { guint8 octet1; proto_item *it; proto_tree *tr; guint32 offset=0; /* * XXX - heuristic to check for misidentified packets. */ if(dissect_possible_rtpv2_packets_as_rtp){ octet1 = tvb_get_guint8( tvb, offset ); if(RTP_VERSION(octet1) == 2){ call_dissector(rtp_handle,tvb,pinfo,tree); return; } } if (check_col(pinfo->cinfo, COL_PROTOCOL)){ col_set_str(pinfo->cinfo, COL_PROTOCOL, "T.38"); } if (check_col(pinfo->cinfo, COL_INFO)){ col_clear(pinfo->cinfo, COL_INFO); } primary_part = TRUE; it=proto_tree_add_protocol_format(tree, proto_t38, tvb, 0, -1, "ITU-T Recommendation T.38"); tr=proto_item_add_subtree(it, ett_t38); if (check_col(pinfo->cinfo, COL_INFO)){ col_append_fstr(pinfo->cinfo, COL_INFO, "UDP: UDPTLPacket "); } offset=dissect_t38_UDPTLPacket(tvb, offset, pinfo, tr); if(offset&0x07){ offset=(offset&0xfffffff8)+8; } if(tvb_length_remaining(tvb,offset>>3)>0){ if(tr){ proto_tree_add_text(tr, tvb, offset, tvb_reported_length_remaining(tvb, offset), "[MALFORMED PACKET or wrong preference settings]"); } if (check_col(pinfo->cinfo, COL_INFO)){ col_append_fstr(pinfo->cinfo, COL_INFO, " [Malformed?]"); } } } static void dissect_t38_tcp_pdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) { proto_item *it; proto_tree *tr; guint32 offset=0; guint16 ifp_packet_number=1; if (check_col(pinfo->cinfo, COL_PROTOCOL)){ col_set_str(pinfo->cinfo, COL_PROTOCOL, "T.38"); } if (check_col(pinfo->cinfo, COL_INFO)){ col_clear(pinfo->cinfo, COL_INFO); } it=proto_tree_add_protocol_format(tree, proto_t38, tvb, 0, -1, "ITU-T Recommendation T.38"); tr=proto_item_add_subtree(it, ett_t38); if (check_col(pinfo->cinfo, COL_INFO)){ col_append_fstr(pinfo->cinfo, COL_INFO, "TCP: IFPPacket"); } while(tvb_length_remaining(tvb,offset>>3)>0) { offset=dissect_t38_IFPPacket(tvb, offset, pinfo, tr); ifp_packet_number++; if(offset&0x07){ offset=(offset&0xfffffff8)+8; } if(tvb_length_remaining(tvb,offset>>3)>0){ if(t38_tpkt_usage == T38_TPKT_ALWAYS){ if(tr){ proto_tree_add_text(tr, tvb, offset, tvb_reported_length_remaining(tvb, offset), "[MALFORMED PACKET or wrong preference settings]"); } if (check_col(pinfo->cinfo, COL_INFO)){ col_append_fstr(pinfo->cinfo, COL_INFO, " [Malformed?]"); } break; } else { if (check_col(pinfo->cinfo, COL_INFO)){ col_append_fstr(pinfo->cinfo, COL_INFO, " IFPPacket#%u",ifp_packet_number); } } } } } static void dissect_t38_tcp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) { primary_part = TRUE; if(t38_tpkt_usage == T38_TPKT_ALWAYS){ dissect_tpkt_encap(tvb,pinfo,tree,t38_tpkt_reassembly,t38_tcp_pdu_handle); } else if((t38_tpkt_usage == T38_TPKT_NEVER) || (is_tpkt(tvb,1) == -1)){ dissect_t38_tcp_pdu(tvb, pinfo, tree); } else { dissect_tpkt_encap(tvb,pinfo,tree,t38_tpkt_reassembly,t38_tcp_pdu_handle); } } static void dissect_t38(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) { if(pinfo->ipproto == IP_PROTO_TCP) { dissect_t38_tcp(tvb, pinfo, tree); } else if(pinfo->ipproto == IP_PROTO_UDP) { dissect_t38_udp(tvb, pinfo, tree); } } /* Ethereal Protocol Registration */ void proto_register_t38(void) { static hf_register_info hf[] = { { &hf_t38_IFPPacket, { "IFPPacket", "t38.IFPPacket", FT_NONE, BASE_NONE, NULL, 0, "IFPPacket sequence", HFILL }}, { &hf_t38_Type_of_msg, { "Type of msg", "t38.Type_of_msg_type", FT_UINT32, BASE_DEC, VALS(Type_of_msg_vals), 0, "Type_of_msg choice", HFILL }}, { &hf_t38_t30_indicator, { "T30 indicator", "t38.t30_indicator", FT_UINT32, BASE_DEC, VALS(t30_indicator_vals), 0, "t30_indicator", HFILL }}, { &hf_t38_data, { "data", "t38.t38_data", FT_UINT32, BASE_DEC, VALS(data_vals), 0, "data", HFILL }}, { &hf_t38_Data_Field, { "Data Field", "t38.Data_Field", FT_NONE, BASE_NONE, NULL, 0, "Data_Field sequence of", HFILL }}, { &hf_t38_Data_Field_item, { "Data_Field_item", "t38.Data_Field_item", FT_NONE, BASE_NONE, NULL, 0, "Data_Field_item sequence", HFILL }}, { &hf_t38_Data_Field_field_type, { "Data_Field_field_type", "t38.Data_Field_field_type", FT_UINT32, BASE_DEC, VALS(Data_Field_field_type_vals), 0, "Data_Field_field_type choice", HFILL }}, { &hf_t38_Data_Field_field_data, { "Data_Field_field_data", "t38.Data_Field_field_data", FT_BYTES, BASE_HEX, NULL, 0, "Data_Field_field_data octet string", HFILL }}, { &hf_t38_UDPTLPacket, { "UDPTLPacket", "t38.UDPTLPacket", FT_NONE, BASE_NONE, NULL, 0, "UDPTLPacket sequence", HFILL }}, { &hf_t38_seq_number, { "Sequence number", "t38.seq_number", FT_UINT32, BASE_DEC, NULL, 0, "seq_number", HFILL }}, { &hf_t38_primary_ifp_packet, { "Primary IFPPacket", "t38.primary_ifp_packet", FT_BYTES, BASE_HEX, NULL, 0, "primary_ifp_packet octet string", HFILL }}, { &hf_t38_primary_ifp_packet_length, { "primary_ifp_packet_length", "t38.primary_ifp_packet_length", FT_UINT32, BASE_DEC, NULL, 0, "primary_ifp_packet_length", HFILL }}, { &hf_t38_error_recovery, { "Error recovery", "t38.error_recovery", FT_UINT32, BASE_DEC, VALS(error_recovery_vals), 0, "error_recovery choice", HFILL }}, { &hf_t38_secondary_ifp_packets, { "Secondary IFPPackets", "t38.secondary_ifp_packets", FT_NONE, BASE_NONE, NULL, 0, "secondary_ifp_packets sequence of", HFILL }}, { &hf_t38_secondary_ifp_packets_item, { "Secondary IFPPackets item", "t38.secondary_ifp_packets_item", FT_BYTES, BASE_HEX, NULL, 0, "secondary_ifp_packets_item octet string", HFILL }}, { &hf_t38_secondary_ifp_packets_item_length, { "secondary_ifp_packets_item_length", "t38.secondary_ifp_packets_item_length", FT_UINT32, BASE_DEC, NULL, 0, "secondary_ifp_packets_item_length", HFILL }}, { &hf_t38_fec_info, { "Fec info", "t38.fec_info", FT_NONE, BASE_NONE, NULL, 0, "fec_info sequence", HFILL }}, { &hf_t38_fec_npackets, { "Fec npackets", "h245.fec_npackets", FT_INT32, BASE_DEC, NULL, 0, "fec_npackets value", HFILL }}, { &hf_t38_fec_data, { "Fec data", "t38.fec_data", FT_NONE, BASE_NONE, NULL, 0, "fec_data sequence of", HFILL }}, { &hf_t38_fec_data_item, { "t38_fec_data_item", "t38.t38_fec_data_item", FT_BYTES, BASE_HEX, NULL, 0, "t38_fec_data_item octet string", HFILL }}, }; static gint *ett[] = { &ett_t38, &ett_t38_IFPPacket, &ett_t38_Type_of_msg, &ett_t38_t30_indicator, &ett_t38_data, &ett_t38_Data_Field, &ett_t38_Data_Field_item, &ett_t38_Data_Field_field_type, &ett_t38_UDPTLPacket, &ett_t38_error_recovery, &ett_t38_secondary_ifp_packets, &ett_t38_fec_info, &ett_t38_fec_data, }; module_t *t38_module; proto_t38 = proto_register_protocol("T38", "T38", "t38"); proto_register_field_array(proto_t38, hf, array_length(hf)); proto_register_subtree_array(ett, array_length(ett)); register_dissector("t38", dissect_t38, proto_t38); t38_module = prefs_register_protocol(proto_t38, proto_reg_handoff_t38); prefs_register_bool_preference(t38_module, "use_pre_corrigendum_asn1_specification", "Use the Pre-Corrigendum ASN.1 specification", "Whether the T.38 dissector should decode using the Pre-Corrigendum T.38 " "ASN.1 specification (1998).", &use_pre_corrigendum_asn1_specification); prefs_register_bool_preference(t38_module, "dissect_possible_rtpv2_packets_as_rtp", "Dissect possible RTP version 2 packets with RTP dissector", "Whether a UDP packet that looks like RTP version 2 packet will " "be dissected as RTP packet or T.38 packet. If enabled there is a risk that T.38 UDPTL " "packets with sequence number higher than 32767 may be dissected as RTP.", &dissect_possible_rtpv2_packets_as_rtp); prefs_register_uint_preference(t38_module, "tcp.port", "T.38 TCP Port", "Set the TCP port for T.38 messages", 10, &global_t38_tcp_port); prefs_register_uint_preference(t38_module, "udp.port", "T.38 UDP Port", "Set the UDP port for T.38 messages", 10, &global_t38_udp_port); prefs_register_bool_preference(t38_module, "reassembly", "Reassemble T.38 PDUs over TPKT over TCP", "Whether the dissector should reassemble T.38 PDUs spanning multiple TCP segments " "when TPKT is used over TCP", &t38_tpkt_reassembly); prefs_register_enum_preference(t38_module, "tpkt_usage", "TPKT used over TCP", "Whether T.38 is used with TPKT for TCP", (gint *)&t38_tpkt_usage,t38_tpkt_options,FALSE); } void proto_reg_handoff_t38(void) { static int t38_prefs_initialized = FALSE; if (!t38_prefs_initialized) { t38_udp_handle=create_dissector_handle(dissect_t38_udp, proto_t38); t38_tcp_handle=create_dissector_handle(dissect_t38_tcp, proto_t38); t38_tcp_pdu_handle=create_dissector_handle(dissect_t38_tcp_pdu, proto_t38); t38_prefs_initialized = TRUE; } else { dissector_delete("tcp.port", tcp_port, t38_tcp_handle); dissector_delete("udp.port", udp_port, t38_udp_handle); } tcp_port = global_t38_tcp_port; udp_port = global_t38_udp_port; dissector_add("tcp.port", tcp_port, t38_tcp_handle); dissector_add("udp.port", udp_port, t38_udp_handle); rtp_handle = find_dissector("rtp"); }