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-rw-r--r--epan/dissectors/packet-t38.c929
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diff --git a/epan/dissectors/packet-t38.c b/epan/dissectors/packet-t38.c
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+/* packet-t38.c
+ * Routines for T.38 packet dissection
+ * 2003 Hans Viens
+ *
+ * $Id$
+ *
+ * Ethereal - Network traffic analyzer
+ * By Gerald Combs <gerald@ethereal.com>
+ * 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 <glib.h>
+#include <epan/packet.h>
+#include <epan/conversation.h>
+
+#include <stdio.h>
+#include <string.h>
+
+#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,"<unknown>"));
+ }
+ 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,"<unknown>"));
+ }
+ 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,"<unknown>"));
+ }
+
+ 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");
+}
generated by cgit v1.2.3 (git 2.25.1) at 2024-06-08 21:51:52 +0000