diff options
author | Guy Harris <guy@alum.mit.edu> | 2001-12-16 22:30:11 +0000 |
---|---|---|
committer | Guy Harris <guy@alum.mit.edu> | 2001-12-16 22:30:11 +0000 |
commit | c52144b652b91b134ea412494759784499446853 (patch) | |
tree | c564a40124c843f02d1d55d3a49df6193ccbf6c1 /packet-m2tp.c | |
parent | 794f0c04f4948c824d64e8ee1a987c03e716082f (diff) |
M2TP support, from Heinz Prantner.
svn path=/trunk/; revision=4409
Diffstat (limited to 'packet-m2tp.c')
-rw-r--r-- | packet-m2tp.c | 683 |
1 files changed, 683 insertions, 0 deletions
diff --git a/packet-m2tp.c b/packet-m2tp.c new file mode 100644 index 0000000000..38fc4ec199 --- /dev/null +++ b/packet-m2tp.c @@ -0,0 +1,683 @@ +/* packet-m2tp.c + * Routines for M2TP User Adaptation Layer dissection + * M2TP - MTP2 Transparent Proxy - is a Radisys proprietary + * protocol based on the IETF SIGTRAN standard + * + * Copyright 2001, Heinz Prantner <heinz.prantner[AT]radisys.com> + * + * $Id: packet-m2tp.c,v 1.1 2001/12/16 22:30:09 guy Exp $ + * + * Ethereal - Network traffic analyzer + * By Gerald Combs <gerald@ethereal.com> + * Copyright 1998 Gerald Combs + * + * Copied from packet-m3ua.c + * Thanks to Michael Tuexen for his valuable improvements + * + * 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. + */ + +#ifdef HAVE_CONFIG_H +# include "config.h" +#endif + +#include <glib.h> + +#include "packet.h" + +#define SCTP_PORT_M2TP 9908 /* unassigned port number (not assigned by IANA) */ +#define M2TP_PAYLOAD_PROTO_ID 99 /* s-link */ + +#define VERSION_LENGTH 1 +#define RESERVED_LENGTH 1 +#define MESSAGE_CLASS_LENGTH 1 +#define MESSAGE_TYPE_LENGTH 1 +#define MESSAGE_LENGTH_LENGTH 4 +#define COMMON_HEADER_LENGTH (VERSION_LENGTH + RESERVED_LENGTH + MESSAGE_CLASS_LENGTH + \ + MESSAGE_TYPE_LENGTH + MESSAGE_LENGTH_LENGTH) + +#define VERSION_OFFSET 0 +#define RESERVED_OFFSET (VERSION_OFFSET + VERSION_LENGTH) +#define MESSAGE_CLASS_OFFSET (RESERVED_OFFSET + RESERVED_LENGTH) +#define MESSAGE_TYPE_OFFSET (MESSAGE_CLASS_OFFSET + MESSAGE_CLASS_LENGTH) +#define MESSAGE_LENGTH_OFFSET (MESSAGE_TYPE_OFFSET + MESSAGE_TYPE_LENGTH) + +#define PARAMETER_TAG_LENGTH 2 +#define PARAMETER_LENGTH_LENGTH 2 +#define PARAMETER_HEADER_LENGTH (PARAMETER_TAG_LENGTH + PARAMETER_LENGTH_LENGTH) + +#define PARAMETER_TAG_OFFSET 0 +#define PARAMETER_LENGTH_OFFSET (PARAMETER_TAG_OFFSET + PARAMETER_TAG_LENGTH) +#define PARAMETER_VALUE_OFFSET (PARAMETER_LENGTH_OFFSET + PARAMETER_LENGTH_LENGTH) +#define PARAMETER_HEADER_OFFSET PARAMETER_TAG_OFFSET + +#define INTERFACE_IDENTIFIER_PARAMETER_TAG 1 +#define MASTER_SLAVE_INDICATOR_PARAMETER_TAG 2 +#define M2TP_USER_IDENTIFIER_PARAMETER_TAG 3 +#define INFO_PARAMETER_TAG 4 +#define DIAGNOSTIC_INFORMATION_PARAMETER_TAG 7 +#define HEARTBEAT_DATA_PARAMETER_TAG 9 +#define REASON_PARAMETER_TAG 10 +#define ERROR_CODE_PARAMETER_TAG 12 +#define PROTOCOL_DATA_PARAMETER_TAG 13 + + +static const value_string m2tp_parameter_tag_values[] = { + { INTERFACE_IDENTIFIER_PARAMETER_TAG, "Interface Identifier" }, + { MASTER_SLAVE_INDICATOR_PARAMETER_TAG, "Master Slave Indicator" }, + { M2TP_USER_IDENTIFIER_PARAMETER_TAG, "M2tp User Identifier" }, + { INFO_PARAMETER_TAG, "Info" }, + { DIAGNOSTIC_INFORMATION_PARAMETER_TAG, "Diagnostic Information" }, + { HEARTBEAT_DATA_PARAMETER_TAG, "Heartbeat Data" }, + { REASON_PARAMETER_TAG, "Reason" }, + { ERROR_CODE_PARAMETER_TAG, "Error Code" }, + { PROTOCOL_DATA_PARAMETER_TAG, "Protocol Data" }, + { 0, NULL } }; + +#define PROTOCOL_VERSION_RELEASE_1 1 + +static const value_string m2tp_protocol_version_values[] = { + { PROTOCOL_VERSION_RELEASE_1, "Release 1" }, + { 0, NULL } }; + +#define MESSAGE_CLASS_MGMT_MESSAGE 0 +#define MESSAGE_CLASS_SGSM_MESSAGE 3 +#define MESSAGE_CLASS_MAUP_MESSAGE 6 +#define MESSAGE_CLASS_DATA_MESSAGE 255 + +static const value_string m2tp_message_class_values[] = { + { MESSAGE_CLASS_MGMT_MESSAGE, "Management Messages" }, + { MESSAGE_CLASS_SGSM_MESSAGE, "SG State Maintenance Messages" }, + { MESSAGE_CLASS_MAUP_MESSAGE, "MTP2 User Adaptation Messages" }, + { MESSAGE_CLASS_DATA_MESSAGE, "User Data Messages" }, + { 0, NULL } }; + +/* management messages */ +#define MESSAGE_TYPE_ERR 0 + +/* sg state maintenance messages */ +#define MESSAGE_TYPE_UP 1 +#define MESSAGE_TYPE_DOWN 2 +#define MESSAGE_TYPE_BEAT 3 +#define MESSAGE_TYPE_UP_ACK 4 +#define MESSAGE_TYPE_DOWN_ACK 5 +#define MESSAGE_TYPE_BEAT_ACK 6 + +/* mtp2 user message */ +#define MESSAGE_TYPE_DATA 1 + + +static const value_string m2tp_message_class_type_values[] = { + { MESSAGE_CLASS_MGMT_MESSAGE * 256 + MESSAGE_TYPE_ERR, "Error (ERR)" }, + { MESSAGE_CLASS_DATA_MESSAGE * 256 + MESSAGE_TYPE_DATA, "Payload data (DATA)" }, + { MESSAGE_CLASS_SGSM_MESSAGE * 256 + MESSAGE_TYPE_UP, "ASP up (UP)" }, + { MESSAGE_CLASS_SGSM_MESSAGE * 256 + MESSAGE_TYPE_DOWN, "ASP down (DOWN)" }, + { MESSAGE_CLASS_SGSM_MESSAGE * 256 + MESSAGE_TYPE_BEAT, "Heartbeat (BEAT)" }, + { MESSAGE_CLASS_SGSM_MESSAGE * 256 + MESSAGE_TYPE_UP_ACK, "ASP up ack (UP ACK)" }, + { MESSAGE_CLASS_SGSM_MESSAGE * 256 + MESSAGE_TYPE_DOWN_ACK, "ASP down ack (DOWN ACK)" }, + { MESSAGE_CLASS_SGSM_MESSAGE * 256 + MESSAGE_TYPE_BEAT_ACK, "Heartbeat ack (BEAT ACK)" }, + { 0, NULL } }; + +static const value_string m2tp_message_class_type_acro_values[] = { + { MESSAGE_CLASS_MGMT_MESSAGE * 256 + MESSAGE_TYPE_ERR, "ERR" }, + { MESSAGE_CLASS_DATA_MESSAGE * 256 + MESSAGE_TYPE_DATA, "DATA" }, + { MESSAGE_CLASS_SGSM_MESSAGE * 256 + MESSAGE_TYPE_UP, "ASP_UP" }, + { MESSAGE_CLASS_SGSM_MESSAGE * 256 + MESSAGE_TYPE_DOWN, "ASP_DOWN" }, + { MESSAGE_CLASS_SGSM_MESSAGE * 256 + MESSAGE_TYPE_BEAT, "BEAT" }, + { MESSAGE_CLASS_SGSM_MESSAGE * 256 + MESSAGE_TYPE_UP_ACK, "ASP_UP_ACK" }, + { MESSAGE_CLASS_SGSM_MESSAGE * 256 + MESSAGE_TYPE_DOWN_ACK, "ASP_DOWN_ACK" }, + { MESSAGE_CLASS_SGSM_MESSAGE * 256 + MESSAGE_TYPE_BEAT_ACK, "BEAT_ACK" }, + { 0, NULL } }; + + + +#define HEARTBEAT_PERIOD_OFFSET PARAMETER_VALUE_OFFSET + +#define INTERFACE_IDENTIFIER_LENGTH 4 +#define INTERFACE_IDENTIFIER_OFFSET PARAMETER_VALUE_OFFSET + +#define M2TP_USER_LENGTH 4 +#define M2TP_USER_OFFSET PARAMETER_VALUE_OFFSET + +#define PROTOCOL_DATA_OFFSET PARAMETER_VALUE_OFFSET + +#define MASTER_SLAVE_LENGTH 4 +#define MASTER_SLAVE_OFFSET PARAMETER_VALUE_OFFSET + +#define REASON_LENGTH 4 +#define REASON_OFFSET PARAMETER_VALUE_OFFSET + +#define HEART_BEAT_DATA_OFFSET PARAMETER_VALUE_OFFSET + +#define ERROR_CODE_LENGTH 4 +#define ERROR_CODE_OFFSET PARAMETER_VALUE_OFFSET + +#define INFO_STRING_OFFSET PARAMETER_VALUE_OFFSET + +#define BSN_OFFSET PARAMETER_VALUE_OFFSET +#define FSN_OFFSET PARAMETER_VALUE_OFFSET+1 + +#define M2TP_USER_MTP2 1 +#define M2TP_USER_Q921 2 +#define M2TP_USER_FRAME_RELAY 3 + +static const value_string m2tp_user_identifier_values[] = { + { M2TP_USER_MTP2, "MTP2" }, + { M2TP_USER_Q921, "Q.921" }, + { M2TP_USER_FRAME_RELAY, "Frame Relay" }, + { 0, NULL }}; + +#define M2TP_MODE_MASTER 1 +#define M2TP_MODE_SLAVE 2 + +static const value_string m2tp_mode_values[] = { + { M2TP_MODE_MASTER, "Master" }, + { M2TP_MODE_SLAVE, "Slave" }, + { 0, NULL}}; + +#define M2TP_ERROR_CODE_INVALID_VERSION 1 +#define M2TP_ERROR_CODE_INVALID_INTERFACE_IDENTIFIER 2 +#define M2TP_ERROR_CODE_INVALID_ADAPTATION_LAYER_IDENTIFIER 3 +#define M2TP_ERROR_CODE_INVALID_MESSAGE_TYPE 4 +#define M2TP_ERROR_CODE_INVALID_TRAFFIC_HANDLING_MODE 5 +#define M2TP_ERROR_CODE_UNEXPECTED_MESSAGE 6 +#define M2TP_ERROR_CODE_PROTOCOL_ERROR 7 +#define M2TP_ERROR_CODE_INVALID_STREAM_IDENTIFIER 8 +#define M2TP_ERROR_CODE_INCOMPATIBLE_MASTER_SLAVE_CONFIGURATION 9 + +static const value_string m2tp_error_code_values[] = { + { M2TP_ERROR_CODE_INVALID_VERSION, "Invalid Version" }, + { M2TP_ERROR_CODE_INVALID_INTERFACE_IDENTIFIER, "Invalid Interface Identifier" }, + { M2TP_ERROR_CODE_INVALID_ADAPTATION_LAYER_IDENTIFIER, "Invalid Adaptation Layer Identifier" }, + { M2TP_ERROR_CODE_INVALID_MESSAGE_TYPE, "Invalid Message Type" }, + { M2TP_ERROR_CODE_INVALID_TRAFFIC_HANDLING_MODE, "Invalid Traffic Handling Mode" }, + { M2TP_ERROR_CODE_UNEXPECTED_MESSAGE, "Unexpected Message" }, + { M2TP_ERROR_CODE_PROTOCOL_ERROR, "Protocol Error" }, + { M2TP_ERROR_CODE_INVALID_STREAM_IDENTIFIER, "Invalid Stream Identified" }, + { M2TP_ERROR_CODE_INCOMPATIBLE_MASTER_SLAVE_CONFIGURATION,"Incompatible Master Slave Configuration" }, + { 0, NULL } }; + +#define MANAGEMENT_ORDER_REASON_CODE 1 +#define MTP_RELEASE_REASON_CODE 2 + +static const value_string m2tp_reason_code_values[] = { + { MANAGEMENT_ORDER_REASON_CODE, "Management Order" }, + { MTP_RELEASE_REASON_CODE, "MTP Release" }, + { 0, NULL } }; + + +/* Initialize the protocol and registered fields */ +static int proto_m2tp = -1; +static int hf_m2tp_version = -1; +static int hf_m2tp_reserved = -1; +static int hf_m2tp_message_class = -1; +static int hf_m2tp_message_type = -1; +static int hf_m2tp_message_length = -1; +static int hf_m2tp_parameter_tag = -1; +static int hf_m2tp_parameter_length = -1; +static int hf_m2tp_parameter_value = -1; +static int hf_m2tp_parameter_padding = -1; +static int hf_m2tp_interface_identifier = -1; +static int hf_m2tp_user = -1; +static int hf_m2tp_master_slave = -1; +static int hf_m2tp_info_string = -1; +static int hf_m2tp_heartbeat_data = -1; +static int hf_m2tp_diagnostic_info = -1; +static int hf_m2tp_error_code = -1; +static int hf_m2tp_reason = -1; + +/* Initialize the subtree pointers */ +static gint ett_m2tp = -1; +static gint ett_m2tp_parameter = -1; + +static dissector_handle_t mtp2_handle; +static int mtp2_proto_id; + +static guint +nr_of_padding_bytes (guint length) +{ + guint remainder; + + remainder = length % 4; + + if (remainder == 0) + return 0; + else + return 4 - remainder; +} + +/* Common Header */ +static void +dissect_m2tp_common_header(tvbuff_t *common_header_tvb, packet_info *pinfo, proto_tree *m2tp_tree) +{ + guint8 version, reserved, message_class, message_type; + guint32 message_length; + + /* Extract the common header */ + version = tvb_get_guint8(common_header_tvb, VERSION_OFFSET); + reserved = tvb_get_guint8(common_header_tvb, RESERVED_OFFSET); + message_class = tvb_get_guint8(common_header_tvb, MESSAGE_CLASS_OFFSET); + message_type = tvb_get_guint8(common_header_tvb, MESSAGE_TYPE_OFFSET); + message_length = tvb_get_ntohl (common_header_tvb, MESSAGE_LENGTH_OFFSET); + + if ((check_col(pinfo->cinfo, COL_INFO)) && (message_class != MESSAGE_CLASS_DATA_MESSAGE)){ + col_append_str(pinfo->cinfo, COL_INFO, + val_to_str(message_class * 256 + message_type, m2tp_message_class_type_acro_values, "reserved")); + col_append_str(pinfo->cinfo, COL_INFO, " "); + }; + + if (m2tp_tree) { + /* add the components of the common header to the protocol tree */ + proto_tree_add_uint(m2tp_tree, hf_m2tp_version, common_header_tvb, VERSION_OFFSET, VERSION_LENGTH, version); + proto_tree_add_uint(m2tp_tree, hf_m2tp_reserved, common_header_tvb, RESERVED_OFFSET, RESERVED_LENGTH, reserved); + proto_tree_add_uint(m2tp_tree, hf_m2tp_message_class, common_header_tvb, MESSAGE_CLASS_OFFSET, MESSAGE_CLASS_LENGTH, message_class); + proto_tree_add_uint_format(m2tp_tree, hf_m2tp_message_type, + common_header_tvb, MESSAGE_TYPE_OFFSET, MESSAGE_TYPE_LENGTH, + message_type, "Message type: %u (%s)", + message_type, val_to_str(message_class * 256 + message_type, m2tp_message_class_type_values, "reserved")); + proto_tree_add_uint(m2tp_tree, hf_m2tp_message_length, common_header_tvb, MESSAGE_LENGTH_OFFSET, MESSAGE_LENGTH_LENGTH, message_length); + }; +} + +/* Interface Identifier */ +static void +dissect_m2tp_interface_identifier_parameter(tvbuff_t *parameter_tvb, proto_tree *parameter_tree, proto_item *parameter_item) +{ + guint32 parameter_value; + + if (parameter_tree) { + parameter_value = tvb_get_ntohl(parameter_tvb, PARAMETER_VALUE_OFFSET); + proto_tree_add_uint(parameter_tree, hf_m2tp_interface_identifier, parameter_tvb, INTERFACE_IDENTIFIER_OFFSET, INTERFACE_IDENTIFIER_LENGTH, parameter_value); + proto_item_set_text(parameter_item, "Interface Identifier (%u)", parameter_value); + } +} + +/* Master Slave Indicator */ +static void +dissect_m2tp_master_slave_parameter (tvbuff_t *parameter_tvb, proto_tree *parameter_tree, proto_item *parameter_item) +{ + guint32 parameter_value; + + if (parameter_tree) { + parameter_value = tvb_get_ntohl(parameter_tvb, PARAMETER_VALUE_OFFSET); + proto_tree_add_uint(parameter_tree, hf_m2tp_master_slave, parameter_tvb, MASTER_SLAVE_OFFSET, MASTER_SLAVE_LENGTH, parameter_value); + proto_item_set_text(parameter_item, "Master Slave Indicator (%s)", val_to_str(parameter_value, m2tp_mode_values, "unknown")); + } +} + +/* M2tp User Identifier */ +static void +dissect_m2tp_user_identifier_parameter (tvbuff_t *parameter_tvb, proto_tree *parameter_tree, proto_item *parameter_item) +{ + guint32 parameter_value; + + if (parameter_tree) { + parameter_value = tvb_get_ntohl(parameter_tvb, PARAMETER_VALUE_OFFSET); + proto_tree_add_uint(parameter_tree, hf_m2tp_user, parameter_tvb, M2TP_USER_OFFSET, M2TP_USER_LENGTH, parameter_value); + proto_item_set_text(parameter_item, "M2TP User Identifier (%u)", parameter_value); + } +} + +/* Info String */ +static void +dissect_m2tp_info_parameter(tvbuff_t *parameter_tvb, proto_tree *parameter_tree, proto_item *parameter_item) +{ + guint16 length, info_string_length; + char *info_string; + + if (parameter_tree) { + length = tvb_get_ntohs(parameter_tvb, PARAMETER_LENGTH_OFFSET); + info_string_length = length - PARAMETER_HEADER_LENGTH; + info_string = (char *)tvb_get_ptr(parameter_tvb, INFO_STRING_OFFSET, info_string_length); + proto_tree_add_string(parameter_tree, hf_m2tp_info_string, parameter_tvb, INFO_STRING_OFFSET, info_string_length, info_string); + proto_item_set_text(parameter_item, "Info String (%.*s)", info_string_length, info_string); + } +} + +/* Diagnostic Information */ +static void +dissect_m2tp_diagnostic_information_parameter(tvbuff_t *parameter_tvb, proto_tree *parameter_tree, proto_item *parameter_item) +{ + guint16 length, diagnostic_info_length; + + if (parameter_tree) { + length = tvb_get_ntohs(parameter_tvb, PARAMETER_LENGTH_OFFSET); + diagnostic_info_length = length - PARAMETER_HEADER_LENGTH; + proto_tree_add_bytes(parameter_tree, hf_m2tp_diagnostic_info, parameter_tvb, PARAMETER_VALUE_OFFSET, diagnostic_info_length, + tvb_get_ptr(parameter_tvb, PARAMETER_VALUE_OFFSET, diagnostic_info_length)); + proto_item_set_text(parameter_item, "Diagnostic information (%u byte%s)", diagnostic_info_length, plurality(diagnostic_info_length, "", "s")); + } +} + +/* Heartbeat Data */ +static void +dissect_m2tp_heartbeat_data_parameter(tvbuff_t *parameter_tvb, proto_tree *parameter_tree, proto_item *parameter_item) +{ + guint16 length, heartbeat_data_length; + + if (parameter_tree) { + length = tvb_get_ntohs(parameter_tvb, PARAMETER_LENGTH_OFFSET); + heartbeat_data_length = length - PARAMETER_HEADER_LENGTH; + proto_tree_add_bytes(parameter_tree, hf_m2tp_heartbeat_data, parameter_tvb, PARAMETER_VALUE_OFFSET, heartbeat_data_length, + tvb_get_ptr(parameter_tvb, PARAMETER_VALUE_OFFSET, heartbeat_data_length)); + proto_item_set_text(parameter_item, "Heartbeat data (%u byte%s)", heartbeat_data_length, plurality(heartbeat_data_length, "", "s")); + } +} + +/* Reason Parameter */ +static void +dissect_m2tp_reason_parameter(tvbuff_t *parameter_tvb, proto_tree *parameter_tree, proto_item *parameter_item) +{ + guint32 reason; + + if (parameter_tree) { + reason = tvb_get_ntohl(parameter_tvb, REASON_OFFSET); + proto_tree_add_uint(parameter_tree, hf_m2tp_reason, parameter_tvb, REASON_OFFSET, REASON_LENGTH, reason); + proto_item_set_text(parameter_item, "Reason parameter (%s)", val_to_str(reason, m2tp_reason_code_values, "unknown")); + } +} + +/* Error Code */ +static void +dissect_m2tp_error_code_parameter(tvbuff_t *parameter_tvb, proto_tree *parameter_tree, proto_item *parameter_item) +{ + guint32 error_code; + + if (parameter_tree) { + error_code = tvb_get_ntohl(parameter_tvb, ERROR_CODE_OFFSET); + proto_tree_add_uint(parameter_tree, hf_m2tp_error_code, parameter_tvb, ERROR_CODE_OFFSET, ERROR_CODE_LENGTH, error_code); + proto_item_set_text(parameter_item, "Error code parameter (%s)", val_to_str(error_code, m2tp_error_code_values, "unknown")); + } +} + +/* Protocol Data */ +static void +dissect_m2tp_protocol_data_parameter(tvbuff_t *parameter_tvb, proto_tree *parameter_tree, proto_item *parameter_item, packet_info *pinfo, proto_item *m2tp_item, proto_tree *tree) +{ + guint16 length, protocol_data_length, padding_length; + tvbuff_t *mtp2_tvb; + + length = tvb_get_ntohs(parameter_tvb, PARAMETER_LENGTH_OFFSET); + padding_length = nr_of_padding_bytes(length); + protocol_data_length = length - PARAMETER_HEADER_LENGTH; + + mtp2_tvb = tvb_new_subset(parameter_tvb, PARAMETER_VALUE_OFFSET, protocol_data_length, protocol_data_length); + call_dissector(mtp2_handle, mtp2_tvb, pinfo, tree); + + if ((check_col(pinfo->cinfo, COL_INFO)) && (!proto_is_protocol_enabled(mtp2_proto_id))) + col_append_str(pinfo->cinfo, COL_INFO, "DATA"); + + if (parameter_tree) { + proto_item_set_text(parameter_item, "Protocol data (SS7 message)"); + proto_item_set_len(parameter_item, proto_item_get_len(parameter_item) - protocol_data_length - padding_length); + proto_item_set_len(m2tp_item, proto_item_get_len(m2tp_item) - protocol_data_length - padding_length); + + } +} + +/* Unknown Parameter */ +static void +dissect_m2tp_unknown_parameter(tvbuff_t *parameter_tvb, proto_tree *parameter_tree, proto_item *parameter_item) +{ + guint16 tag, length, parameter_value_length; + + if (parameter_tree) { + tag = tvb_get_ntohs(parameter_tvb, PARAMETER_TAG_OFFSET); + length = tvb_get_ntohs(parameter_tvb, PARAMETER_LENGTH_OFFSET); + + parameter_value_length = length - PARAMETER_HEADER_LENGTH; + proto_tree_add_bytes(parameter_tree, hf_m2tp_parameter_value, + parameter_tvb, PARAMETER_VALUE_OFFSET, parameter_value_length, + tvb_get_ptr(parameter_tvb, PARAMETER_VALUE_OFFSET, parameter_value_length)); + + proto_item_set_text(parameter_item, "Parameter with tag %u and %u byte%s value", tag, parameter_value_length, plurality(parameter_value_length, "", "s")); + } +} + +/* M2TP Parameter */ +static void +dissect_m2tp_parameter(tvbuff_t *parameter_tvb, packet_info *pinfo, proto_tree *m2tp_tree, proto_item *m2tp_item, proto_tree *tree) +{ + guint16 tag, length, padding_length, total_length; + proto_item *parameter_item = NULL; + proto_tree *parameter_tree = NULL; + + /* extract tag and length from the parameter */ + tag = tvb_get_ntohs(parameter_tvb, PARAMETER_TAG_OFFSET); + length = tvb_get_ntohs(parameter_tvb, PARAMETER_LENGTH_OFFSET); + + /* calculate padding and total length */ + padding_length = nr_of_padding_bytes(length); + total_length = length + padding_length; + + if (tree) { + /* create proto_tree stuff */ + parameter_item = proto_tree_add_text(m2tp_tree, parameter_tvb, PARAMETER_HEADER_OFFSET, total_length, "Incomplete parameter"); + parameter_tree = proto_item_add_subtree(parameter_item, ett_m2tp_parameter); + + /* add tag and length to the m2tp tree */ + proto_tree_add_uint(parameter_tree, hf_m2tp_parameter_tag, parameter_tvb, PARAMETER_TAG_OFFSET, PARAMETER_TAG_LENGTH, tag); + proto_tree_add_uint(parameter_tree, hf_m2tp_parameter_length, parameter_tvb, PARAMETER_LENGTH_OFFSET, PARAMETER_LENGTH_LENGTH, length); + } + + switch(tag) { + case INTERFACE_IDENTIFIER_PARAMETER_TAG: + dissect_m2tp_interface_identifier_parameter(parameter_tvb, parameter_tree, parameter_item); + break; + case MASTER_SLAVE_INDICATOR_PARAMETER_TAG: + dissect_m2tp_master_slave_parameter(parameter_tvb, parameter_tree, parameter_item); + break; + case M2TP_USER_IDENTIFIER_PARAMETER_TAG: + dissect_m2tp_user_identifier_parameter(parameter_tvb, parameter_tree, parameter_item); + break; + case INFO_PARAMETER_TAG: + dissect_m2tp_info_parameter(parameter_tvb, parameter_tree, parameter_item); + break; + case DIAGNOSTIC_INFORMATION_PARAMETER_TAG: + dissect_m2tp_diagnostic_information_parameter(parameter_tvb, parameter_tree, parameter_item); + break; + case HEARTBEAT_DATA_PARAMETER_TAG: + dissect_m2tp_heartbeat_data_parameter(parameter_tvb, parameter_tree, parameter_item); + break; + case REASON_PARAMETER_TAG: + dissect_m2tp_reason_parameter(parameter_tvb, parameter_tree, parameter_item); + break; + case ERROR_CODE_PARAMETER_TAG: + dissect_m2tp_error_code_parameter(parameter_tvb, parameter_tree, parameter_item); + break; + case PROTOCOL_DATA_PARAMETER_TAG: + dissect_m2tp_protocol_data_parameter(parameter_tvb, parameter_tree, parameter_item, pinfo, m2tp_item, tree); + break; + default: + dissect_m2tp_unknown_parameter(parameter_tvb, parameter_tree, parameter_item); + break; + }; + + if ((parameter_tree) && (padding_length > 0)) + proto_tree_add_bytes(parameter_tree, hf_m2tp_parameter_padding, + parameter_tvb, PARAMETER_HEADER_OFFSET + length, padding_length, + tvb_get_ptr(parameter_tvb, PARAMETER_HEADER_OFFSET + length, padding_length)); +} + +/* M2TP Message */ +static void +dissect_m2tp_message(tvbuff_t *message_tvb, packet_info *pinfo, proto_item *m2tp_item, proto_tree *m2tp_tree, proto_tree *tree) +{ + gint offset, length, padding_length, total_length; + tvbuff_t *common_header_tvb, *parameter_tvb; + + offset = 0; + + /* extract and process the common header */ + common_header_tvb = tvb_new_subset(message_tvb, offset, COMMON_HEADER_LENGTH, COMMON_HEADER_LENGTH); + dissect_m2tp_common_header(common_header_tvb, pinfo, m2tp_tree); + offset += COMMON_HEADER_LENGTH; + + /* extract zero or more parameters and process them individually */ + while(tvb_length_remaining(message_tvb, offset)) { + length = tvb_get_ntohs(message_tvb, offset + PARAMETER_LENGTH_OFFSET); + padding_length = nr_of_padding_bytes(length); + total_length = length + padding_length; + /* create a tvb for the parameter including the padding bytes */ + parameter_tvb = tvb_new_subset(message_tvb, offset, total_length, total_length); + dissect_m2tp_parameter(parameter_tvb, pinfo, m2tp_tree, m2tp_item, tree); + /* get rid of the handled parameter */ + offset += total_length; + } +} + +/* M2tp */ +static void +dissect_m2tp(tvbuff_t *message_tvb, packet_info *pinfo, proto_tree *tree) +{ + proto_item *m2tp_item; + proto_tree *m2tp_tree; + + /* make entry in the Protocol column on summary display */ + if (check_col(pinfo->cinfo, COL_PROTOCOL)) + col_set_str(pinfo->cinfo, COL_PROTOCOL, "M2TP"); + + /* In the interest of speed, if "tree" is NULL, don't do any work not + necessary to generate protocol tree items. */ + if (tree) { + /* create the m2tp protocol tree */ + m2tp_item = proto_tree_add_item(tree, proto_m2tp, message_tvb, 0, tvb_length(message_tvb), FALSE); + m2tp_tree = proto_item_add_subtree(m2tp_item, ett_m2tp); + } else { + m2tp_item = NULL; + m2tp_tree = NULL; + }; + /* dissect the message */ + dissect_m2tp_message(message_tvb, pinfo, m2tp_item, m2tp_tree, tree); +} + +/* Register the protocol with Ethereal */ +void +proto_register_m2tp(void) +{ + + /* Setup list of header fields */ + static hf_register_info hf[] = { + { &hf_m2tp_version, + { "Version", "m2tp.version", + FT_UINT8, BASE_DEC, VALS(m2tp_protocol_version_values), 0x0, + "", HFILL} + }, + { &hf_m2tp_reserved, + { "Reserved", "m2tp.reserved", + FT_UINT8, BASE_HEX, NULL, 0x0, + "", HFILL} + }, + { &hf_m2tp_message_class, + { "Message class", "m2tp.message_class", + FT_UINT8, BASE_DEC, VALS(m2tp_message_class_values), 0x0, + "", HFILL} + }, + { &hf_m2tp_message_type, + { "Message Type", "m2tp.message_type", + FT_UINT8, BASE_DEC, NULL, 0x0, + "", HFILL} + }, + { &hf_m2tp_message_length, + { "Message length", "m2tp.message_length", + FT_UINT32, BASE_DEC, NULL, 0x0, + "", HFILL} + }, + { &hf_m2tp_parameter_tag, + { "Parameter Tag", "m2tp.parameter_tag", + FT_UINT16, BASE_DEC, VALS(m2tp_parameter_tag_values), 0x0, + "", HFILL} + }, + { &hf_m2tp_parameter_length, + { "Parameter length", "m2tp.parameter_length", + FT_UINT16, BASE_DEC, NULL, 0x0, + "", HFILL} + }, + { &hf_m2tp_parameter_value, + { "Parameter Value", "m2tp.parameter_value", + FT_BYTES, BASE_NONE, NULL, 0x0, + "", HFILL } + }, + { &hf_m2tp_parameter_padding, + { "Padding", "m2tp.parameter_padding", + FT_BYTES, BASE_NONE, NULL, 0x0, + "", HFILL } + }, + { &hf_m2tp_interface_identifier, + { "Interface Identifier", "m2tp.interface_identifier", + FT_UINT32, BASE_DEC, NULL, 0x0, + "", HFILL} + }, + { &hf_m2tp_user, + { "M2tp User Identifier", "m2tp.user_identifier", + FT_UINT32, BASE_DEC, VALS(m2tp_user_identifier_values), 0x0, + "", HFILL} + }, + { &hf_m2tp_master_slave, + { "Master Slave Indicator", "m2tp.master_slave", + FT_UINT32, BASE_DEC, VALS(m2tp_mode_values), 0x0, + "", HFILL} + }, + { &hf_m2tp_info_string, + { "Info string", "m2tp.info_string", + FT_STRING, BASE_DEC, NULL, 0x0, + "", HFILL} + }, + { &hf_m2tp_diagnostic_info, + { "Diagnostic information", "m2tp.diagnostic_info", + FT_BYTES, BASE_NONE, NULL, 0x0, + "", HFILL } + }, + { &hf_m2tp_heartbeat_data, + { "Heartbeat data", "m2tp.heartbeat_data", + FT_BYTES, BASE_NONE, NULL, 0x0, + "", HFILL } + }, + { &hf_m2tp_error_code, + { "Error code", "m2tp.error_code", + FT_UINT32, BASE_DEC, VALS(m2tp_error_code_values), 0x0, + "", HFILL} + }, + { &hf_m2tp_reason, + { "Reason", "m2tp.reason", + FT_UINT32, BASE_DEC, NULL, 0x0, + "", HFILL} + }, + }; + + /* Setup protocol subtree array */ + static gint *ett[] = { + &ett_m2tp, + &ett_m2tp_parameter, + }; + + /* Register the protocol name and description */ + proto_m2tp = proto_register_protocol("MTP 2 Transparent Proxy", "M2TP", "m2tp"); + + /* Required function calls to register the header fields and subtrees used */ + proto_register_field_array(proto_m2tp, hf, array_length(hf)); + proto_register_subtree_array(ett, array_length(ett)); +}; + +void +proto_reg_handoff_m2tp(void) +{ + dissector_handle_t m2tp_handle; + mtp2_handle = find_dissector("mtp2"); + mtp2_proto_id = proto_get_id_by_filter_name("mtp2"); + m2tp_handle = create_dissector_handle(dissect_m2tp, proto_m2tp); + dissector_add("sctp.ppi", M2TP_PAYLOAD_PROTO_ID, m2tp_handle); + dissector_add("sctp.port", SCTP_PORT_M2TP, m2tp_handle); +} |