/* packet-mbtcp.c * Routines for Modbus/TCP and Modbus/UDP dissection * By Riaan Swart * Copyright 2001, Institute for Applied Computer Science * University of Stellenbosch * * See * * http://www.modbus.org/ * * for information on Modbus/TCP. * * Updated to v1.1b of the Modbus Application Protocol specification * Michael Mann * Copyright 2011 * * $Id$ * * 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #ifdef HAVE_CONFIG_H # include "config.h" #endif #include #include "packet-tcp.h" #include "packet-mbtcp.h" /* Initialize the protocol and registered fields */ static int proto_mbtcp = -1; static int proto_modbus = -1; static int hf_mbtcp_transid = -1; static int hf_mbtcp_protid = -1; static int hf_mbtcp_len = -1; static int hf_mbtcp_unitid = -1; static int hf_mbtcp_functioncode = -1; static int hf_modbus_reference = -1; static int hf_modbus_lreference = -1; static int hf_modbus_reftype = -1; static int hf_modbus_readref = -1; static int hf_modbus_writeref = -1; static int hf_modbus_wordcnt = -1; static int hf_modbus_readwordcnt = -1; static int hf_modbus_writewordcnt = -1; static int hf_modbus_bytecnt = -1; static int hf_modbus_lbytecnt = -1; static int hf_modbus_bitcnt = -1; static int hf_modbus_exceptioncode = -1; static int hf_modbus_diag_sf = -1; static int hf_modbus_status = -1; static int hf_modbus_event_count = -1; static int hf_modbus_message_count = -1; static int hf_modbus_event_recv_comm_err = -1; static int hf_modbus_event_recv_char_over = -1; static int hf_modbus_event_recv_lo_mode = -1; static int hf_modbus_event_recv_broadcast = -1; static int hf_modbus_event_send_read_ex = -1; static int hf_modbus_event_send_slave_abort_ex = -1; static int hf_modbus_event_send_slave_busy_ex = -1; static int hf_modbus_event_send_slave_nak_ex = -1; static int hf_modbus_event_send_write_timeout = -1; static int hf_modbus_event_send_lo_mode = -1; static int hf_modbus_andmask = -1; static int hf_modbus_ormask = -1; static int hf_modbus_data = -1; static int hf_modbus_mei = -1; static int hf_modbus_read_device_id = -1; static int hf_modbus_object_id = -1; static int hf_modbus_num_objects = -1; static int hf_modbus_list_object_len = -1; static int hf_modbus_conformity_level = -1; static int hf_modbus_more_follows = -1; static int hf_modbus_next_object_id = -1; static int hf_modbus_object_str_value = -1; /* Initialize the subtree pointers */ static gint ett_mbtcp = -1; static gint ett_modbus_hdr = -1; static gint ett_group_hdr = -1; static gint ett_events = -1; static gint ett_events_recv = -1; static gint ett_events_send = -1; static gint ett_device_id_objects = -1; static gint ett_device_id_object_items = -1; static dissector_table_t mbtcp_dissector_table; static dissector_table_t modbus_dissector_table; static dissector_handle_t modbus_handle; static gboolean mbtcp_desegment = TRUE; static int classify_packet(packet_info *pinfo) { /* see if nature of packets can be derived from src/dst ports */ /* if so, return as found */ if (( pinfo->srcport == PORT_MBTCP ) && ( pinfo->destport != PORT_MBTCP )) return RESPONSE_PACKET; if (( pinfo->srcport != PORT_MBTCP ) && ( pinfo->destport == PORT_MBTCP )) return QUERY_PACKET; /* else, cannot classify */ return CANNOT_CLASSIFY; } /* Translate function to string, as given on p6 of * "Open Modbus/TCP Specification", release 1 by Andy Swales. */ static const value_string function_code_vals[] = { { READ_COILS, "Read coils" }, { READ_INPUT_DISCRETES, "Read input discretes" }, { READ_MULT_REGS, "Read multiple registers" }, { READ_INPUT_REGS, "Read input registers" }, { WRITE_COIL, "Write coil" }, { WRITE_SINGLE_REG, "Write single register" }, { READ_EXCEPT_STAT, "Read exception status" }, { DIAGNOSTICS, "Diagnostics" }, { GET_COMM_EVENT_CTRS, "Get Comm. Event Counters" }, { GET_COMM_EVENT_LOG, "Get Comm. Event Log" }, { WRITE_MULT_COILS, "Write Multiple Coils" }, { WRITE_MULT_REGS, "Write Multiple Registers" }, { REPORT_SLAVE_ID, "Report Slave ID" }, { READ_FILE_RECORD, "Read File Record" }, { WRITE_FILE_RECORD, "Write File Record" }, { MASK_WRITE_REG, "Mask Write Register" }, { READ_WRITE_REG, "Read Write Register" }, { READ_FIFO_QUEUE, "Read FIFO Queue" }, { ENCAP_INTERFACE_TRANSP, "Encapsulated Interface Transport" }, { 0, NULL } }; /* Translate exception code to string */ static const value_string exception_code_vals[] = { { ILLEGAL_FUNCTION, "Illegal function" }, { ILLEGAL_ADDRESS, "Illegal data address" }, { ILLEGAL_VALUE, "Illegal data value" }, { SLAVE_FAILURE, "Slave device failure" }, { ACKNOWLEDGE, "Acknowledge" }, { SLAVE_BUSY, "Slave device busy" }, { MEMORY_ERR, "Memory parity error" }, { GATEWAY_UNAVAILABLE, "Gateway path unavailable" }, { GATEWAY_TRGT_FAIL, "Gateway target device failed to respond" }, { 0, NULL } }; /* Translate Modbus Encapsulation Interface (MEI) code to string */ static const value_string encap_interface_code_vals[] = { { CANOPEN_REQ_RESP, "CANopen Request/Response " }, { READ_DEVICE_ID, "Read Device Identification" }, { 0, NULL } }; /* Translate Modbus Diagnostic subfunction code to string */ static const value_string diagnostic_code_vals[] = { { RETURN_QUERY_DATA, "Return Query Data" }, { RESTART_COMMUNICATION_OPTION, "Restart Communications Option" }, { RETURN_DIAGNOSTIC_REGISTER, "Return Diagnostic Register" }, { CHANGE_ASCII_INPUT_DELIMITER, "Change ASCII Input Delimiter" }, { FORCE_LISTEN_ONLY_MODE, "Force Listen Only Mode" }, { CLEAR_COUNTERS_AND_DIAG_REG, "Clear Counters and Diagnostic Register" }, { RETURN_BUS_MESSAGE_COUNT, "Return Bus Message Count" }, { RETURN_BUS_COMM_ERROR_COUNT, "Return Bus Communication Error Count" }, { RETURN_BUS_EXCEPTION_ERROR_COUNT, "Return Bus Exception Error Count" }, { RETURN_SLAVE_MESSAGE_COUNT, "Return Slave Message Count" }, { RETURN_SLAVE_NO_RESPONSE_COUNT, "Return Slave No Response Count" }, { RETURN_SLAVE_NAK_COUNT, "Return Slave NAK Count" }, { RETURN_SLAVE_BUSY_COUNT, "Return Slave Busy Count" }, { RETURN_BUS_CHAR_OVERRUN_COUNT, "Return Bus Character Overrun Count" }, { CLEAR_OVERRUN_COUNTER_AND_FLAG, "Clear Overrun Counter and Flag" }, { 0, NULL } }; /* Translate read device code to string */ static const value_string read_device_id_vals[] = { { 1, "Basic Device Identification" }, { 2, "Regular Device Identification" }, { 3, "Extended Device Identification" }, { 4, "Specific Identification Object" }, { 0, NULL } }; /* Translate read device code to string */ static const value_string object_id_vals[] = { { 0, "VendorName" }, { 1, "ProductCode" }, { 2, "MajorMinorRevision" }, { 3, "VendorURL" }, { 4, "ProductName" }, { 5, "ModelName" }, { 6, "UserApplicationName" }, { 0, NULL } }; static const value_string conformity_level_vals[] = { { 0x01, "Basic Device Identification (stream)" }, { 0x02, "Regular Device Identification (stream)" }, { 0x03, "Extended Device Identification (stream)" }, { 0x81, "Basic Device Identification (stream and individual)" }, { 0x82, "Regular Device Identification (stream and individual)" }, { 0x83, "Extended Device Identification (stream and individual)" }, { 0, NULL } }; /* Code to actually dissect the packets */ static void dissect_mbtcp_pdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) { /* Set up structures needed to add the protocol subtree and manage it */ proto_item *mi; proto_tree *mbtcp_tree; int offset, packet_type; tvbuff_t *next_tvb; const char *func_string = ""; const char *pkt_type_str = ""; const char *err_str = ""; guint16 transaction_id, protocol_id, len; guint8 unit_id, function_code, exception_code, subfunction_code; void *p_save_proto_data; /* Make entries in Protocol column on summary display */ col_set_str(pinfo->cinfo, COL_PROTOCOL, "Modbus/TCP"); col_clear(pinfo->cinfo, COL_INFO); transaction_id = tvb_get_ntohs(tvb, 0); protocol_id = tvb_get_ntohs(tvb, 2); len = tvb_get_ntohs(tvb, 4); unit_id = tvb_get_guint8(tvb, 6); function_code = tvb_get_guint8(tvb, 7) & 0x7F; /* Make entries in Info column on summary display */ offset = 0; /* Find exception - last bit set in function code */ if (tvb_get_guint8(tvb, 7) & 0x80) { exception_code = tvb_get_guint8(tvb, offset + 8); } else { exception_code = 0; } if ((function_code == ENCAP_INTERFACE_TRANSP) && (exception_code == 0)) { func_string = val_to_str(tvb_get_guint8(tvb, offset + 8), encap_interface_code_vals, "Encapsulated Interface Transport"); subfunction_code = 1; } else if ((function_code == DIAGNOSTICS) && (exception_code == 0)) { func_string = val_to_str(tvb_get_ntohs(tvb, offset + 8), diagnostic_code_vals, "Diagnostics"); subfunction_code = 1; } else { func_string = val_to_str(function_code, function_code_vals, "Unknown function (%d)"); subfunction_code = 0; } /* "Request" or "Response" */ packet_type = classify_packet(pinfo); if (check_col(pinfo->cinfo, COL_INFO)) { switch ( packet_type ) { case QUERY_PACKET : pkt_type_str="query"; break; case RESPONSE_PACKET : pkt_type_str="response"; break; case CANNOT_CLASSIFY : err_str="Unable to classify as query or response."; pkt_type_str="unknown"; break; default : break; } if ( exception_code != 0 ) err_str="Exception returned "; if (subfunction_code == 0) { if (strlen(err_str) > 0) { col_add_fstr(pinfo->cinfo, COL_INFO, "%8s: trans: %5u; unit: %3u, func: %3u: %s. %s", pkt_type_str, transaction_id, unit_id, function_code, func_string, err_str); } else { col_add_fstr(pinfo->cinfo, COL_INFO, "%8s: trans: %5u; unit: %3u, func: %3u: %s", pkt_type_str, transaction_id, unit_id, function_code, func_string); } } else { if (strlen(err_str) > 0) { col_add_fstr(pinfo->cinfo, COL_INFO, "%8s: trans: %5u; unit: %3u, func: %3u/%3u: %s. %s", pkt_type_str, transaction_id, unit_id, function_code, subfunction_code, func_string, err_str); } else { col_add_fstr(pinfo->cinfo, COL_INFO, "%8s: trans: %5u; unit: %3u, func: %3u/%3u: %s", pkt_type_str, transaction_id, unit_id, function_code, subfunction_code, func_string); } } } /* if a tree exists, perform operations to add fields to it */ if (tree) { mi = proto_tree_add_protocol_format(tree, proto_mbtcp, tvb, offset, len+6, "Modbus/TCP"); mbtcp_tree = proto_item_add_subtree(mi, ett_mbtcp); /* Add items to protocol tree specific to Modbus/TCP */ proto_tree_add_uint(mbtcp_tree, hf_mbtcp_transid, tvb, offset, 2, transaction_id); proto_tree_add_uint(mbtcp_tree, hf_mbtcp_protid, tvb, offset + 2, 2, protocol_id); proto_tree_add_uint(mbtcp_tree, hf_mbtcp_len, tvb, offset + 4, 2, len); proto_tree_add_uint(mbtcp_tree, hf_mbtcp_unitid, tvb, offset + 6, 1, unit_id); /* dissect the Modbus PDU */ next_tvb = tvb_new_subset( tvb, offset+7, len-1, len-1); /* keep packet context */ p_save_proto_data = p_get_proto_data( pinfo->fd, proto_mbtcp ); p_remove_proto_data(pinfo->fd, proto_mbtcp); p_add_proto_data(pinfo->fd, proto_mbtcp, GINT_TO_POINTER(packet_type)); /* Show the undissected payload */ if( tvb_length_remaining(tvb, offset) > 0 ) call_dissector(modbus_handle, next_tvb, pinfo, tree); p_remove_proto_data(pinfo->fd, proto_mbtcp); p_add_proto_data(pinfo->fd, proto_mbtcp, p_save_proto_data); } } static guint get_mbtcp_pdu_len(packet_info *pinfo _U_, tvbuff_t *tvb, int offset) { guint16 plen; /* * Get the length of the data from the encapsulation header. */ plen = tvb_get_ntohs(tvb, offset + 4); /* * That length doesn't include the encapsulation header itself; * add that in. */ return plen + 6; } static int dissect_mbtcp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) { /* Make sure there's at least enough data to determine its a Modbus packet */ if (!tvb_bytes_exist(tvb, 0, 8)) return 0; /* check that it actually looks like Modbus/TCP */ /* protocol id == 0 */ if(tvb_get_ntohs(tvb, 2) != 0 ){ return 0; } /* length is at least 2 (unit_id + function_code) */ if(tvb_get_ntohs(tvb, 4) < 2 ){ return 0; } /* build up protocol tree and iterate over multiple packets */ tcp_dissect_pdus(tvb, pinfo, tree, mbtcp_desegment, 6, get_mbtcp_pdu_len, dissect_mbtcp_pdu); return tvb_length(tvb); } static int dissect_mbudp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) { /* Make sure there's at least enough data to determine its a Modbus packet */ if (!tvb_bytes_exist(tvb, 0, 8)) return 0; /* check that it actually looks like Modbus/UDP */ /* protocol id == 0 */ if(tvb_get_ntohs(tvb, 2) != 0 ){ return 0; } /* length is at least 2 (unit_id + function_code) */ if(tvb_get_ntohs(tvb, 4) < 2 ){ return 0; } /* dissect the PDU */ dissect_mbtcp_pdu(tvb, pinfo, tree); return tvb_length(tvb); } /* Code to allow special handling of mbtcp data */ static void dissect_mbtcp_data(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, guint8 function_code, gint payload_start, gint payload_len) { gint reported_len; tvbuff_t *next_tvb; reported_len = tvb_reported_length_remaining(tvb, payload_start); if ( payload_start < 0 || ( payload_len + payload_start ) == 0 ) return; if ( payload_len != reported_len ) { proto_tree_add_bytes_format(tree, hf_modbus_data, tvb, payload_start, payload_len, NULL, "Data"); return; } next_tvb = tvb_new_subset(tvb, payload_start, payload_len, reported_len); switch ( function_code ) { default: if ( ! dissector_try_string(mbtcp_dissector_table, "data", next_tvb, pinfo, tree) ) proto_tree_add_bytes_format(tree, hf_modbus_data, tvb, payload_start, payload_len, NULL, "Data"); break; } } /* Code to actually dissect the packets */ static int dissect_modbus(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) { proto_tree *modbus_tree, *group_tree, *event_tree, *event_item_tree, *device_objects_tree, *device_objects_item_tree; proto_item *mi, *mf, *me, *mei, *doe, *doie; int offset, group_offset, packet_type, temp_data; const char *func_string = ""; gint payload_start, payload_len, event_index, i, byte_cnt, len, num_objects, object_index, object_len; guint32 group_byte_cnt, group_word_cnt; guint8 function_code, exception_code, mei_code, event_code, object_type; guint16 diagnostic_code; guint8 *object_str; /* Don't need to do anything if there's no tree */ if (tree == NULL) return tvb_length(tvb); len = tvb_length_remaining(tvb, 0); function_code = tvb_get_guint8(tvb, 0) & 0x7F; /* Find exception - last bit set in function code */ if (tvb_get_guint8(tvb, 0) & 0x80 ) { exception_code = tvb_get_guint8(tvb, 1); } else { exception_code = 0; } /* "Request" or "Response" */ packet_type = GPOINTER_TO_INT(p_get_proto_data( pinfo->fd, proto_mbtcp )); /* Make entries in Info column on summary display */ offset = 0; /* Add items to protocol tree specific to Modbus generic */ mf = proto_tree_add_text(tree, tvb, offset, len, "Modbus"); modbus_tree = proto_item_add_subtree(mf, ett_modbus_hdr); mi = proto_tree_add_uint(modbus_tree, hf_mbtcp_functioncode, tvb, offset, 1, function_code); /** detail payload as a function of exception/function code */ func_string = val_to_str(function_code, function_code_vals, "Unknown function"); payload_start = offset + 1; payload_len = len - 1; if (exception_code != 0) { proto_item_set_text(mi, "function %u: %s. Exception: %s", function_code, func_string, val_to_str(exception_code, exception_code_vals, "Unknown exception code (%u)")); proto_tree_add_uint(modbus_tree, hf_modbus_exceptioncode, tvb, payload_start, 1, exception_code); } else { proto_item_set_text(mi, "function %u: %s", function_code, func_string); switch (function_code) { case READ_COILS: case READ_INPUT_DISCRETES: if (packet_type == QUERY_PACKET) { proto_tree_add_item(modbus_tree, hf_modbus_reference, tvb, payload_start, 2, ENC_BIG_ENDIAN); proto_tree_add_item(modbus_tree, hf_modbus_bitcnt, tvb, payload_start + 2, 2, ENC_BIG_ENDIAN); } else if (packet_type == RESPONSE_PACKET) { byte_cnt = (guint32)tvb_get_guint8(tvb, payload_start); proto_tree_add_uint(modbus_tree, hf_modbus_bytecnt, tvb, payload_start, 1, byte_cnt); dissect_mbtcp_data(tvb, pinfo, modbus_tree, function_code, payload_start + 1, byte_cnt); } break; case READ_MULT_REGS: case READ_INPUT_REGS: if (packet_type == QUERY_PACKET) { proto_tree_add_item(modbus_tree, hf_modbus_reference, tvb, payload_start, 2, ENC_BIG_ENDIAN); proto_tree_add_item(modbus_tree, hf_modbus_wordcnt, tvb, payload_start + 2, 2, ENC_BIG_ENDIAN); } else if (packet_type == RESPONSE_PACKET) { byte_cnt = (guint32)tvb_get_guint8(tvb, payload_start); proto_tree_add_uint(modbus_tree, hf_modbus_bytecnt, tvb, payload_start, 1, byte_cnt); dissect_mbtcp_data(tvb, pinfo, modbus_tree, function_code, payload_start + 1, byte_cnt); } break; case WRITE_COIL: if (packet_type == QUERY_PACKET) { proto_tree_add_item(modbus_tree, hf_modbus_reference, tvb, payload_start, 2, ENC_BIG_ENDIAN); dissect_mbtcp_data(tvb, pinfo, modbus_tree, function_code, payload_start + 2, 1); proto_tree_add_text(modbus_tree, tvb, payload_start + 3, 1, "Padding"); } else if (packet_type == RESPONSE_PACKET) { proto_tree_add_item(modbus_tree, hf_modbus_reference, tvb, payload_start, 2, ENC_BIG_ENDIAN); dissect_mbtcp_data(tvb, pinfo, modbus_tree, function_code, payload_start + 2, 1); proto_tree_add_text(modbus_tree, tvb, payload_start + 3, 1, "Padding"); } break; case WRITE_SINGLE_REG: if (packet_type == QUERY_PACKET) { proto_tree_add_item(modbus_tree, hf_modbus_reference, tvb, payload_start, 2, ENC_BIG_ENDIAN); dissect_mbtcp_data(tvb, pinfo, modbus_tree, function_code, payload_start + 2, 2); } else if (packet_type == RESPONSE_PACKET) { proto_tree_add_item(modbus_tree, hf_modbus_reference, tvb, payload_start, 2, ENC_BIG_ENDIAN); dissect_mbtcp_data(tvb, pinfo, modbus_tree, function_code, payload_start + 2, 2); } break; case READ_EXCEPT_STAT: if (packet_type == RESPONSE_PACKET) dissect_mbtcp_data(tvb, pinfo, modbus_tree, function_code, payload_start, 1); break; case DIAGNOSTICS: if ((packet_type == QUERY_PACKET) || (packet_type == RESPONSE_PACKET)) { diagnostic_code = tvb_get_ntohs(tvb, payload_start); proto_tree_add_uint(modbus_tree, hf_modbus_diag_sf, tvb, payload_start, 2, diagnostic_code); switch(diagnostic_code) { case RETURN_QUERY_DATA: if (packet_type == QUERY_PACKET) { if (payload_len > 2) proto_tree_add_text(modbus_tree, tvb, payload_start+2, payload_len-2, "Request Data"); } else if (packet_type == RESPONSE_PACKET) { if (payload_len > 2) proto_tree_add_text(modbus_tree, tvb, payload_start+2, payload_len-2, "Echo Data"); } break; case RESTART_COMMUNICATION_OPTION: temp_data = tvb_get_ntohs(tvb, payload_start+2); if (temp_data == 0) { proto_tree_add_text(modbus_tree, tvb, payload_start+2, 2, "Leave Log"); } else if (temp_data == 0xFF) { proto_tree_add_text(modbus_tree, tvb, payload_start+2, 2, "Clear Log"); } else { proto_tree_add_text(modbus_tree, tvb, payload_start+2, 2, "Unknown"); } break; case RETURN_DIAGNOSTIC_REGISTER: if (packet_type == QUERY_PACKET) { if (payload_len > 2) dissect_mbtcp_data(tvb, pinfo, modbus_tree, function_code, payload_start+2, payload_len-2); } else if (packet_type == RESPONSE_PACKET) { temp_data = tvb_get_ntohs(tvb, payload_start+2); proto_tree_add_text( modbus_tree, tvb, payload_start+2, 2, "Diagnostic Register Contents 0x%04x", temp_data ); } break; case CHANGE_ASCII_INPUT_DELIMITER: temp_data = tvb_get_guint8(tvb, payload_start+2); proto_tree_add_text( modbus_tree, tvb, payload_start+2, 1, "CHAR 0x%02x", temp_data ); break; case RETURN_BUS_MESSAGE_COUNT: if (packet_type == QUERY_PACKET) { if (payload_len > 2) dissect_mbtcp_data(tvb, pinfo, modbus_tree, function_code, payload_start+2, payload_len-2); } else if (packet_type == RESPONSE_PACKET) { temp_data = tvb_get_ntohs(tvb, payload_start+2); proto_tree_add_text( modbus_tree, tvb, payload_start+2, 2, "Total Message Count %d", temp_data ); } break; case RETURN_BUS_COMM_ERROR_COUNT: if (packet_type == QUERY_PACKET) { if (payload_len > 2) dissect_mbtcp_data(tvb, pinfo, modbus_tree, function_code, payload_start+2, payload_len-2); } else if (packet_type == RESPONSE_PACKET) { temp_data = tvb_get_ntohs(tvb, payload_start+2); proto_tree_add_text( modbus_tree, tvb, payload_start+2, 2, "CRC Error Count %d", temp_data ); } break; case RETURN_BUS_EXCEPTION_ERROR_COUNT: if (packet_type == QUERY_PACKET) { if (payload_len > 2) dissect_mbtcp_data(tvb, pinfo, modbus_tree, function_code, payload_start+2, payload_len-2); } else if (packet_type == RESPONSE_PACKET) { temp_data = tvb_get_ntohs(tvb, payload_start+2); proto_tree_add_text( modbus_tree, tvb, payload_start+2, 2, "Exception Error Count %d", temp_data ); } break; case RETURN_SLAVE_MESSAGE_COUNT: if (packet_type == QUERY_PACKET) { if (payload_len > 2) dissect_mbtcp_data(tvb, pinfo, modbus_tree, function_code, payload_start+2, payload_len-2); } else if (packet_type == RESPONSE_PACKET) { temp_data = tvb_get_ntohs(tvb, payload_start+2); proto_tree_add_text( modbus_tree, tvb, payload_start+2, 2, "Slave Message Count %d", temp_data ); } break; case RETURN_SLAVE_NO_RESPONSE_COUNT: if (packet_type == QUERY_PACKET) { if (payload_len > 2) dissect_mbtcp_data(tvb, pinfo, modbus_tree, function_code, payload_start+2, payload_len-2); } else if (packet_type == RESPONSE_PACKET) { temp_data = tvb_get_ntohs(tvb, payload_start+2); proto_tree_add_text( modbus_tree, tvb, payload_start+2, 2, "Slave No Response Count %d", temp_data ); } break; case RETURN_SLAVE_NAK_COUNT: if (packet_type == QUERY_PACKET) { if (payload_len > 2) dissect_mbtcp_data(tvb, pinfo, modbus_tree, function_code, payload_start+2, payload_len-2); } else if (packet_type == RESPONSE_PACKET) { temp_data = tvb_get_ntohs(tvb, payload_start+2); proto_tree_add_text( modbus_tree, tvb, payload_start+2, 2, "Slave NAK Count %d", temp_data ); } break; case RETURN_SLAVE_BUSY_COUNT: if (packet_type == QUERY_PACKET) { if (payload_len > 2) dissect_mbtcp_data(tvb, pinfo, modbus_tree, function_code, payload_start+2, payload_len-2); } else if (packet_type == RESPONSE_PACKET) { temp_data = tvb_get_ntohs(tvb, payload_start+2); proto_tree_add_text( modbus_tree, tvb, payload_start+2, 2, "Slave Device Busy Count %d", temp_data ); } break; case RETURN_BUS_CHAR_OVERRUN_COUNT: if (packet_type == QUERY_PACKET) { if (payload_len > 2) dissect_mbtcp_data(tvb, pinfo, modbus_tree, function_code, payload_start+2, payload_len-2); } else if (packet_type == RESPONSE_PACKET) { temp_data = tvb_get_ntohs(tvb, payload_start+2); proto_tree_add_text( modbus_tree, tvb, payload_start+2, 2, "Slave Character Overrun Count %d", temp_data ); } break; case CLEAR_OVERRUN_COUNTER_AND_FLAG: case FORCE_LISTEN_ONLY_MODE: case CLEAR_COUNTERS_AND_DIAG_REG: default: if (payload_len > 2) dissect_mbtcp_data(tvb, pinfo, modbus_tree, function_code, payload_start+2, payload_len-2); break; } } break; case GET_COMM_EVENT_CTRS: if (packet_type == RESPONSE_PACKET) { proto_tree_add_item(modbus_tree, hf_modbus_status, tvb, payload_start, 2, ENC_BIG_ENDIAN); proto_tree_add_item(modbus_tree, hf_modbus_event_count, tvb, payload_start+2, 2, ENC_BIG_ENDIAN); } break; case GET_COMM_EVENT_LOG: if (packet_type == RESPONSE_PACKET) { byte_cnt = (guint32)tvb_get_guint8(tvb, payload_start); proto_tree_add_uint(modbus_tree, hf_modbus_bytecnt, tvb, payload_start, 1, byte_cnt); proto_tree_add_item(modbus_tree, hf_modbus_status, tvb, payload_start+1, 2, ENC_BIG_ENDIAN); proto_tree_add_item(modbus_tree, hf_modbus_event_count, tvb, payload_start+3, 2, ENC_BIG_ENDIAN); proto_tree_add_item(modbus_tree, hf_modbus_message_count, tvb, payload_start+5, 2, ENC_BIG_ENDIAN); if (byte_cnt-6 > 0) { byte_cnt -= 6; event_index = 0; me = proto_tree_add_text(modbus_tree, tvb, payload_start+7, byte_cnt, "Events"); event_tree = proto_item_add_subtree(me, ett_events); while (byte_cnt > 0) { event_code = tvb_get_guint8(tvb, payload_start+7+event_index); if (event_code == 0) { proto_tree_add_text(event_tree, tvb, payload_start+7+event_index, 1, "Initiated Communication Restart"); } else if (event_code == 4) { proto_tree_add_text(event_tree, tvb, payload_start+7+event_index, 1, "Entered Listen Only Mode"); } else if (event_code & REMOTE_DEVICE_RECV_EVENT_MASK) { mei = proto_tree_add_text(event_tree, tvb, payload_start+7+event_index, 1, "Receive Event: 0x%02X", event_code); event_item_tree = proto_item_add_subtree(mei, ett_events_recv); /* add subtrees to describe each event bit */ proto_tree_add_item(event_item_tree, hf_modbus_event_recv_comm_err, tvb, payload_start+7+event_index, 1, ENC_LITTLE_ENDIAN ); proto_tree_add_item(event_item_tree, hf_modbus_event_recv_char_over, tvb, payload_start+7+event_index, 1, ENC_LITTLE_ENDIAN ); proto_tree_add_item(event_item_tree, hf_modbus_event_recv_lo_mode, tvb, payload_start+7+event_index, 1, ENC_LITTLE_ENDIAN ); proto_tree_add_item(event_item_tree, hf_modbus_event_recv_broadcast, tvb, payload_start+7+event_index, 1, ENC_LITTLE_ENDIAN ); } else if ((event_code & REMOTE_DEVICE_SEND_EVENT_MASK) == REMOTE_DEVICE_SEND_EVENT_VALUE) { mei = proto_tree_add_text(event_tree, tvb, payload_start+7+event_index, 1, "Send Event: 0x%02X", event_code); event_item_tree = proto_item_add_subtree(mei, ett_events_send); /* add subtrees to describe each event bit */ proto_tree_add_item(event_item_tree, hf_modbus_event_send_read_ex, tvb, payload_start+7+event_index, 1, ENC_LITTLE_ENDIAN ); proto_tree_add_item(event_item_tree, hf_modbus_event_send_slave_abort_ex, tvb, payload_start+7+event_index, 1, ENC_LITTLE_ENDIAN ); proto_tree_add_item(event_item_tree, hf_modbus_event_send_slave_busy_ex, tvb, payload_start+7+event_index, 1, ENC_LITTLE_ENDIAN ); proto_tree_add_item(event_item_tree, hf_modbus_event_send_slave_nak_ex, tvb, payload_start+7+event_index, 1, ENC_LITTLE_ENDIAN ); proto_tree_add_item(event_item_tree, hf_modbus_event_send_write_timeout, tvb, payload_start+7+event_index, 1, ENC_LITTLE_ENDIAN ); proto_tree_add_item(event_item_tree, hf_modbus_event_send_lo_mode, tvb, payload_start+7+event_index, 1, ENC_LITTLE_ENDIAN ); } else { proto_tree_add_text(event_tree, tvb, payload_start+7+event_index, 1, "Unknown Event"); } byte_cnt--; event_index++; } } } break; case WRITE_MULT_COILS: if (packet_type == QUERY_PACKET) { proto_tree_add_item(modbus_tree, hf_modbus_reference, tvb, payload_start, 2, ENC_BIG_ENDIAN); proto_tree_add_item(modbus_tree, hf_modbus_bitcnt, tvb, payload_start + 2, 2, ENC_BIG_ENDIAN); byte_cnt = (guint32)tvb_get_guint8(tvb, payload_start + 4); proto_tree_add_uint(modbus_tree, hf_modbus_bytecnt, tvb, payload_start + 4, 1, byte_cnt); dissect_mbtcp_data(tvb, pinfo, modbus_tree, function_code, payload_start + 5, byte_cnt); } else if (packet_type == RESPONSE_PACKET) { proto_tree_add_item(modbus_tree, hf_modbus_reference, tvb, payload_start, 2, ENC_BIG_ENDIAN); proto_tree_add_item(modbus_tree, hf_modbus_bitcnt, tvb, payload_start + 2, 2, ENC_BIG_ENDIAN); } break; case WRITE_MULT_REGS: if (packet_type == QUERY_PACKET) { proto_tree_add_item(modbus_tree, hf_modbus_reference, tvb, payload_start, 2, ENC_BIG_ENDIAN); proto_tree_add_item(modbus_tree, hf_modbus_wordcnt, tvb, payload_start + 2, 2, ENC_BIG_ENDIAN); byte_cnt = (guint32)tvb_get_guint8(tvb, payload_start + 4); proto_tree_add_uint(modbus_tree, hf_modbus_bytecnt, tvb, payload_start + 4, 1, byte_cnt); dissect_mbtcp_data(tvb, pinfo, modbus_tree, function_code, payload_start + 5, byte_cnt); } else if (packet_type == RESPONSE_PACKET) { proto_tree_add_item(modbus_tree, hf_modbus_reference, tvb, payload_start, 2, ENC_BIG_ENDIAN); proto_tree_add_item(modbus_tree, hf_modbus_wordcnt, tvb, payload_start + 2, 2, ENC_BIG_ENDIAN); } break; case READ_FILE_RECORD: if (packet_type == QUERY_PACKET) { byte_cnt = (guint32)tvb_get_guint8(tvb, payload_start); proto_tree_add_uint(modbus_tree, hf_modbus_bytecnt, tvb, payload_start, 1, byte_cnt); /* add subtrees to describe each group of packet */ group_offset = payload_start + 1; for (i = 0; i < byte_cnt / 7; i++) { mi = proto_tree_add_text( modbus_tree, tvb, group_offset, 7, "Group %u", i); group_tree = proto_item_add_subtree(mi, ett_group_hdr); proto_tree_add_item(group_tree, hf_modbus_reftype, tvb, group_offset, 1, ENC_BIG_ENDIAN); proto_tree_add_item(group_tree, hf_modbus_lreference, tvb, group_offset + 1, 4, ENC_BIG_ENDIAN); proto_tree_add_item(group_tree, hf_modbus_wordcnt, tvb, group_offset + 5, 2, ENC_BIG_ENDIAN); group_offset += 7; } } else if (packet_type == RESPONSE_PACKET) { byte_cnt = (guint32)tvb_get_guint8(tvb, payload_start); proto_tree_add_uint(modbus_tree, hf_modbus_bytecnt, tvb, payload_start, 1, byte_cnt); /* add subtrees to describe each group of packet */ group_offset = payload_start + 1; i = 0; while (byte_cnt > 0) { group_byte_cnt = (guint32)tvb_get_guint8(tvb, group_offset); mi = proto_tree_add_text( modbus_tree, tvb, group_offset, group_byte_cnt + 1, "Group %u", i); group_tree = proto_item_add_subtree(mi, ett_group_hdr); proto_tree_add_uint(group_tree, hf_modbus_bytecnt, tvb, group_offset, 1, group_byte_cnt); proto_tree_add_item(group_tree, hf_modbus_reftype, tvb, group_offset + 1, 1, ENC_BIG_ENDIAN); dissect_mbtcp_data(tvb, pinfo, group_tree, function_code, group_offset + 2, group_byte_cnt - 1); group_offset += (group_byte_cnt + 1); byte_cnt -= (group_byte_cnt + 1); i++; } } break; case WRITE_FILE_RECORD: if ((packet_type == QUERY_PACKET) || (packet_type == RESPONSE_PACKET)) { byte_cnt = (guint32)tvb_get_guint8(tvb, payload_start); proto_tree_add_uint(modbus_tree, hf_modbus_bytecnt, tvb, payload_start, 1, byte_cnt); /* add subtrees to describe each group of packet */ group_offset = payload_start + 1; i = 0; while (byte_cnt > 0) { group_word_cnt = tvb_get_ntohs(tvb, group_offset + 5); group_byte_cnt = (2 * group_word_cnt) + 7; mi = proto_tree_add_text( modbus_tree, tvb, group_offset, group_byte_cnt, "Group %u", i); group_tree = proto_item_add_subtree(mi, ett_group_hdr); proto_tree_add_item(group_tree, hf_modbus_reftype, tvb, group_offset, 1, ENC_BIG_ENDIAN); proto_tree_add_item(group_tree, hf_modbus_lreference, tvb, group_offset + 1, 4, ENC_BIG_ENDIAN); proto_tree_add_uint(group_tree, hf_modbus_wordcnt, tvb, group_offset + 5, 2, group_word_cnt); dissect_mbtcp_data(tvb, pinfo, group_tree, function_code, group_offset + 7, group_byte_cnt - 7); group_offset += group_byte_cnt; byte_cnt -= group_byte_cnt; i++; } } break; case MASK_WRITE_REG: if ((packet_type == QUERY_PACKET) || (packet_type == RESPONSE_PACKET)) { proto_tree_add_item(modbus_tree, hf_modbus_reference, tvb, payload_start, 2, ENC_BIG_ENDIAN); proto_tree_add_item(modbus_tree, hf_modbus_andmask, tvb, payload_start + 2, 2, ENC_BIG_ENDIAN); proto_tree_add_item(modbus_tree, hf_modbus_ormask, tvb, payload_start + 4, 2, ENC_BIG_ENDIAN); } break; case READ_WRITE_REG: if (packet_type == QUERY_PACKET) { proto_tree_add_item(modbus_tree, hf_modbus_readref, tvb, payload_start, 2, ENC_BIG_ENDIAN); proto_tree_add_item(modbus_tree, hf_modbus_readwordcnt, tvb, payload_start + 2, 2, ENC_BIG_ENDIAN); proto_tree_add_item(modbus_tree, hf_modbus_writeref, tvb, payload_start + 4, 2, ENC_BIG_ENDIAN); proto_tree_add_item(modbus_tree, hf_modbus_writewordcnt, tvb, payload_start + 6, 2, ENC_BIG_ENDIAN); byte_cnt = (guint32)tvb_get_guint8(tvb, payload_start + 8); proto_tree_add_uint(modbus_tree, hf_modbus_bytecnt, tvb, payload_start + 8, 1, byte_cnt); dissect_mbtcp_data(tvb, pinfo, modbus_tree, function_code, payload_start + 9, byte_cnt); } else if (packet_type == RESPONSE_PACKET) { byte_cnt = (guint32)tvb_get_guint8(tvb, payload_start); proto_tree_add_uint(modbus_tree, hf_modbus_bytecnt, tvb, payload_start, 1, byte_cnt); dissect_mbtcp_data(tvb, pinfo, modbus_tree, function_code, payload_start + 1, byte_cnt); } break; case READ_FIFO_QUEUE: if (packet_type == QUERY_PACKET) proto_tree_add_item(modbus_tree, hf_modbus_reference, tvb, payload_start, 2, ENC_BIG_ENDIAN); else if (packet_type == RESPONSE_PACKET) { byte_cnt = (guint32)tvb_get_ntohs(tvb, payload_start); proto_tree_add_uint(modbus_tree, hf_modbus_lbytecnt, tvb, payload_start, 2, byte_cnt); proto_tree_add_item(modbus_tree, hf_modbus_wordcnt, tvb, payload_start + 2, 2, ENC_BIG_ENDIAN); dissect_mbtcp_data(tvb, pinfo, modbus_tree, function_code, payload_start + 4, byte_cnt - 2); } break; case ENCAP_INTERFACE_TRANSP: if (packet_type == QUERY_PACKET) { proto_tree_add_item(modbus_tree, hf_modbus_mei, tvb, payload_start, 1, ENC_BIG_ENDIAN); mei_code = tvb_get_guint8(tvb, payload_start); switch (mei_code) { case READ_DEVICE_ID: proto_tree_add_item(modbus_tree, hf_modbus_read_device_id, tvb, payload_start+1, 1, ENC_BIG_ENDIAN); proto_tree_add_item(modbus_tree, hf_modbus_object_id, tvb, payload_start+2, 1, ENC_BIG_ENDIAN); break; case CANOPEN_REQ_RESP: /* CANopen protocol not part of the Modbus/TCP specification */ default: if (payload_len > 1) dissect_mbtcp_data(tvb, pinfo, modbus_tree, function_code, payload_start, payload_len-1); break; } } else if (packet_type == RESPONSE_PACKET) { proto_tree_add_item(modbus_tree, hf_modbus_mei, tvb, payload_start, 1, ENC_BIG_ENDIAN); mei_code = tvb_get_guint8(tvb, payload_start); switch (mei_code) { case READ_DEVICE_ID: proto_tree_add_item(modbus_tree, hf_modbus_read_device_id, tvb, payload_start+1, 1, ENC_BIG_ENDIAN); proto_tree_add_item(modbus_tree, hf_modbus_conformity_level, tvb, payload_start+2, 1, ENC_BIG_ENDIAN); proto_tree_add_item(modbus_tree, hf_modbus_more_follows, tvb, payload_start+3, 1, ENC_BIG_ENDIAN); proto_tree_add_item(modbus_tree, hf_modbus_next_object_id, tvb, payload_start+4, 1, ENC_BIG_ENDIAN); num_objects = tvb_get_guint8(tvb, payload_start+5); proto_tree_add_uint(modbus_tree, hf_modbus_num_objects, tvb, payload_start+5, 1, num_objects); doe = proto_tree_add_text(modbus_tree, tvb, payload_start+6, payload_len-6, "Objects"); object_index = 0; for (i = 1; i <= num_objects; i++) { device_objects_tree = proto_item_add_subtree(doe, ett_device_id_objects); /* add each "object item" as its own subtree */ /* compute length of object */ object_type = tvb_get_guint8(tvb, payload_start+6+object_index); object_len = tvb_get_guint8(tvb, payload_start+6+object_index+1); doie = proto_tree_add_text(device_objects_tree, tvb, payload_start+6+object_index, 2+object_len, "Object #%d", i); device_objects_item_tree = proto_item_add_subtree(doie, ett_device_id_object_items); proto_tree_add_item(device_objects_item_tree, hf_modbus_object_id, tvb, payload_start+6+object_index, 1, ENC_BIG_ENDIAN); object_index++; proto_tree_add_uint(device_objects_item_tree, hf_modbus_list_object_len, tvb, payload_start+6+object_index, 1, object_len); object_index++; if (object_type < 7) { object_str = tvb_get_string(tvb, payload_start+6+object_index, object_len); proto_tree_add_string(device_objects_item_tree, hf_modbus_object_str_value, tvb, payload_start+6+object_index, object_len, object_str); g_free(object_str); } else { if (object_len > 0) proto_tree_add_text(device_objects_item_tree, tvb, payload_start+6+object_index, object_len, "Object Value"); } object_index += object_len; } break; case CANOPEN_REQ_RESP: /* CANopen protocol not part of the Modbus/TCP specification */ default: if (payload_len > 1) dissect_mbtcp_data(tvb, pinfo, modbus_tree, function_code, payload_start, payload_len-1); break; } } break; case REPORT_SLAVE_ID: default: if (payload_len > 0) dissect_mbtcp_data(tvb, pinfo, modbus_tree, function_code, payload_start, payload_len); break; } } return tvb_length(tvb); } /* Register the protocol with Wireshark */ void proto_register_modbus(void) { /* Setup list of header fields See Section 1.6.1 for details*/ static hf_register_info hf[] = { /* Modbus/TCP header fields */ { &hf_mbtcp_transid, { "transaction identifier", "mbtcp.trans_id", FT_UINT16, BASE_DEC, NULL, 0x0, NULL, HFILL } }, { &hf_mbtcp_protid, { "protocol identifier", "mbtcp.prot_id", FT_UINT16, BASE_DEC, NULL, 0x0, NULL, HFILL } }, { &hf_mbtcp_len, { "length", "mbtcp.len", FT_UINT16, BASE_DEC, NULL, 0x0, NULL, HFILL } }, /* Modbus header fields */ { &hf_mbtcp_unitid, { "unit identifier", "mbtcp.modbus.unit_id", FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL } }, { &hf_mbtcp_functioncode, { "function code", "mbtcp.modbus.func_code", FT_UINT8, BASE_DEC, VALS(function_code_vals), 0x0, NULL, HFILL } }, { &hf_modbus_reference, { "reference number", "mbtcp.modbus.reference_num", FT_UINT16, BASE_DEC, NULL, 0x0, NULL, HFILL } }, { &hf_modbus_lreference, { "reference number (32 bit)", "mbtcp.modbus.reference_num_32", FT_UINT32, BASE_DEC, NULL, 0x0, NULL, HFILL } }, { &hf_modbus_reftype, { "reference type", "mbtcp.modbus.reference_type", FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL } }, { &hf_modbus_readref, { "read reference number", "mbtcp.modbus.read_reference_num", FT_UINT16, BASE_DEC, NULL, 0x0, NULL, HFILL } }, { &hf_modbus_writeref, { "write reference number", "mbtcp.modbus.write_reference_num", FT_UINT16, BASE_DEC, NULL, 0x0, NULL, HFILL } }, { &hf_modbus_wordcnt, { "word count", "mbtcp.modbus.word_cnt", FT_UINT16, BASE_DEC, NULL, 0x0, NULL, HFILL } }, { &hf_modbus_readwordcnt, { "read word count", "mbtcp.modbus.read_word_cnt", FT_UINT16, BASE_DEC, NULL, 0x0, NULL, HFILL } }, { &hf_modbus_writewordcnt, { "write word count", "mbtcp.modbus.write_word_cnt", FT_UINT16, BASE_DEC, NULL, 0x0, NULL, HFILL } }, { &hf_modbus_bitcnt, { "bit count", "mbtcp.modbus.bit_cnt", FT_UINT16, BASE_DEC, NULL, 0x0, NULL, HFILL } }, { &hf_modbus_bytecnt, { "byte count", "mbtcp.modbus.byte_cnt", FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL } }, { &hf_modbus_lbytecnt, { "byte count (16-bit)", "mbtcp.modbus.byte_cnt_16", FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL } }, { &hf_modbus_exceptioncode, { "exception code", "mbtcp.modbus.exception_code", FT_UINT8, BASE_DEC, VALS(exception_code_vals), 0x0, NULL, HFILL } }, { &hf_modbus_diag_sf, { "diagnostic code", "mbtcp.modbus.diagnostic_code", FT_UINT16, BASE_DEC, VALS(diagnostic_code_vals), 0x0, NULL, HFILL } }, { &hf_modbus_status, { "status", "mbtcp.modbus.ev_status", FT_UINT16, BASE_HEX, NULL, 0x0, NULL, HFILL } }, { &hf_modbus_event_count, { "event count", "mbtcp.modbus.ev_count", FT_UINT16, BASE_DEC, NULL, 0x0, NULL, HFILL } }, { &hf_modbus_message_count, { "message count", "mbtcp.modbus.ev_msg_count", FT_UINT16, BASE_DEC, NULL, 0x0, NULL, HFILL } }, { &hf_modbus_event_recv_comm_err, { "Communication Error", "mbtcp.modbus.ev_recv_comm_err", FT_UINT8, BASE_DEC, NULL, 0x02, NULL, HFILL } }, { &hf_modbus_event_recv_char_over, { "Character Overrun", "mbtcp.modbus.ev_recv_char_over", FT_UINT8, BASE_DEC, NULL, 0x10, NULL, HFILL } }, { &hf_modbus_event_recv_lo_mode, { "Currently in Listen Only Mode", "mbtcp.modbus.ev_recv_lo_mode", FT_UINT8, BASE_DEC, NULL, 0x20, NULL, HFILL } }, { &hf_modbus_event_recv_broadcast, { "Broadcast Received", "mbtcp.modbus.ev_recv_broadcast", FT_UINT8, BASE_DEC, NULL, 0x40, NULL, HFILL } }, { &hf_modbus_event_send_read_ex, { "Read Exception Sent", "mbtcp.modbus.ev_send_read_ex", FT_UINT8, BASE_DEC, NULL, 0x01, NULL, HFILL } }, { &hf_modbus_event_send_slave_abort_ex, { "Slave Abort Exception Sent", "mbtcp.modbus.ev_send_slave_abort_ex", FT_UINT8, BASE_DEC, NULL, 0x02, NULL, HFILL } }, { &hf_modbus_event_send_slave_busy_ex, { "Slave Busy Exception Sent", "mbtcp.modbus.ev_send_slave_busy_ex", FT_UINT8, BASE_DEC, NULL, 0x04, NULL, HFILL } }, { &hf_modbus_event_send_slave_nak_ex, { "Slave Program NAK Exception Sent", "mbtcp.modbus.ev_send_slave_nak_ex", FT_UINT8, BASE_DEC, NULL, 0x08, NULL, HFILL } }, { &hf_modbus_event_send_write_timeout, { "Write Timeout Error Occurred", "mbtcp.modbus.ev_send_write_timeout", FT_UINT8, BASE_DEC, NULL, 0x10, NULL, HFILL } }, { &hf_modbus_event_send_lo_mode, { "Currently in Listen Only Mode", "mbtcp.modbus.ev_send_lo_mode", FT_UINT8, BASE_DEC, NULL, 0x20, NULL, HFILL } }, { &hf_modbus_andmask, { "AND mask", "mbtcp.modbus.and_mask", FT_UINT16, BASE_HEX, NULL, 0x0, NULL, HFILL } }, { &hf_modbus_ormask, { "OR mask", "mbtcp.modbus.or_mask", FT_UINT16, BASE_HEX, NULL, 0x0, NULL, HFILL } }, { &hf_modbus_data, { "Data", "mbtcp.modbus.data", FT_BYTES, BASE_NONE, NULL, 0x0, NULL, HFILL } }, { &hf_modbus_mei, { "MEI type", "mbtcp.modbus.mei", FT_UINT8, BASE_DEC, VALS(encap_interface_code_vals), 0x0, NULL, HFILL } }, { &hf_modbus_read_device_id, { "Read Device ID", "mbtcp.modbus.read_device_id", FT_UINT8, BASE_DEC, VALS(read_device_id_vals), 0x0, NULL, HFILL } }, { &hf_modbus_object_id, { "Object ID", "mbtcp.modbus.object_id", FT_UINT8, BASE_DEC, VALS(object_id_vals), 0x0, NULL, HFILL } }, { &hf_modbus_num_objects, { "Number of Objects", "mbtcp.modbus.num_objects", FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL } }, { &hf_modbus_list_object_len, { "Object length", "mbtcp.modbus.objects_len", FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL } }, { &hf_modbus_conformity_level, { "Conformity Level", "mbtcp.modbus.conformity_level", FT_UINT8, BASE_HEX, VALS(conformity_level_vals), 0x0, NULL, HFILL } }, { &hf_modbus_more_follows, { "More Follows", "mbtcp.modbus.more_follows", FT_UINT8, BASE_HEX, NULL, 0x0, NULL, HFILL } }, { &hf_modbus_next_object_id, { "Next Object ID", "mbtcp.modbus.next_object_id", FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL } }, { &hf_modbus_object_str_value, { "Object String Value", "mbtcp.modbus.object_str_value", FT_STRING, BASE_NONE, NULL, 0x0, NULL, HFILL } } }; /* Setup protocol subtree array */ static gint *ett[] = { &ett_mbtcp, &ett_modbus_hdr, &ett_group_hdr, &ett_events, &ett_events_recv, &ett_events_send, &ett_device_id_objects, &ett_device_id_object_items }; /* Register the protocol name and description */ proto_mbtcp = proto_register_protocol("Modbus/TCP", "Modbus/TCP", "mbtcp"); proto_modbus = proto_register_protocol("Modbus", "Modbus", "modbus"); /* Registering protocol to be called by another dissector */ new_register_dissector("mbtcp", dissect_mbtcp, proto_mbtcp); new_register_dissector("modbus", dissect_modbus, proto_modbus); /* Registering subdissectors table */ mbtcp_dissector_table = register_dissector_table("mbtcp.modbus.data", "Modbus/TCP Data", FT_STRING, BASE_NONE); modbus_dissector_table = register_dissector_table("mbtcp.prot_id", "protocol identifier", FT_UINT16, BASE_DEC); /* Required function calls to register the header fields and subtrees used */ proto_register_field_array(proto_mbtcp, hf, array_length(hf)); proto_register_subtree_array(ett, array_length(ett)); } /* If this dissector uses sub-dissector registration add a registration routine. This format is required because a script is used to find these routines and create the code that calls these routines. */ void proto_reg_handoff_mbtcp(void) { dissector_handle_t mbtcp_handle, mbudp_handle; mbtcp_handle = new_create_dissector_handle(dissect_mbtcp, proto_mbtcp); dissector_add_uint("tcp.port", PORT_MBTCP, mbtcp_handle); mbudp_handle = new_create_dissector_handle(dissect_mbudp, proto_mbtcp); dissector_add_uint("udp.port", PORT_MBTCP, mbudp_handle); modbus_handle = new_create_dissector_handle(dissect_modbus, proto_modbus); dissector_add_uint("mbtcp.prot_id", MODBUS_PROTOCOL_ID, modbus_handle); }