diff options
Diffstat (limited to 'epan/dissectors/packet-mbtcp.c')
| -rw-r--r-- | epan/dissectors/packet-mbtcp.c | 692 |
1 files changed, 692 insertions, 0 deletions
diff --git a/epan/dissectors/packet-mbtcp.c b/epan/dissectors/packet-mbtcp.c new file mode 100644 index 0000000000..4d9549b45f --- /dev/null +++ b/epan/dissectors/packet-mbtcp.c @@ -0,0 +1,692 @@ +/* packet-mbtcp.c + * Routines for Modbus/TCP dissection + * By Riaan Swart <rswart@cs.sun.ac.za> + * Copyright 2001, Institute for Applied Computer Science + * University of Stellenbosch + * + * See + * + * http://www.modicon.com/openmbus/ + * + * for information on Modbus/TCP. + * + * $Id$ + * + * 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. + */ + +#ifdef HAVE_CONFIG_H +# include "config.h" +#endif + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> + +#include <glib.h> + +#include <epan/packet.h> + +#define DEBUG + +#define TCP_PORT_MBTCP 502 /* Modbus/TCP located on TCP port 502 */ + +/* Modbus protocol function codes */ +#define read_coils 1 +#define read_input_discretes 2 +#define read_mult_regs 3 +#define read_input_regs 4 +#define write_coil 5 +#define write_single_reg 6 +#define read_except_stat 7 +#define diagnostics 8 +#define program_484 9 +#define poll_484 10 +#define get_comm_event_ctrs 11 +#define get_comm_event_log 12 +#define program_584_984 13 +#define poll_584_984 14 +#define force_mult_coils 15 +#define write_mult_regs 16 +#define report_slave_id 17 +#define program_884_u84 18 +#define reset_comm_link 19 +#define read_genl_ref 20 +#define write_genl_ref 21 +#define mask_write_reg 22 +#define read_write_reg 23 +#define read_fifo_queue 24 +#define program_ConCept 40 +#define firmware_replace 125 +#define program_584_984_2 126 +#define report_local_addr_mb 127 + +/* Modbus protocol exception codes */ +#define illegal_function 0x01 +#define illegal_address 0x02 +#define illegal_value 0x03 +#define illegal_response 0x04 +#define acknowledge 0x05 +#define slave_busy 0x06 +#define negative_ack 0x07 +#define memory_err 0x08 +#define gateway_unavailable 0x0a +#define gateway_trgt_fail 0x0b + +/* return codes of function classifying packets as query/response */ +#define query_packet 0 +#define response_packet 1 +#define cannot_classify 2 + +/* Modbus header */ +typedef struct _modbus_hdr { + guint8 unit_id; /* unit identifier (previously slave addr) */ + guint8 function_code; /* Modbus function code */ +} modbus_hdr; + +/* Modbus/TCP header, containing the Modbus header */ +typedef struct _mbtcp_hdr { + guint16 transaction_id; /* copied by svr, usually 0 */ + guint16 protocol_id; /* always 0 */ + guint16 len; /* len of data that follows */ + modbus_hdr mdbs_hdr; /* mdbus hdr directly after mdbs/tcp hdr * + * in packet */ +} mbtcp_hdr; + +/* Initialize the protocol and registered fields */ +static int proto_mbtcp = -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_andmask = -1; +static int hf_modbus_ormask = -1; + +/* Initialize the subtree pointers */ +static gint ett_mbtcp = -1; +static gint ett_modbus_hdr = -1; +static gint ett_group_hdr = -1; + +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 ( ( 502 == pinfo->srcport && 502 != pinfo->destport ) || + ( 502 != pinfo->srcport && 502 == pinfo->destport ) ) { + /* the slave is receiving queries on port 502 */ + if ( 502 == pinfo->srcport ) + return response_packet; + else if ( 502 == pinfo->destport ) + 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" }, + { program_484, "Program (484)" }, + { poll_484, "Poll (484)" }, + { get_comm_event_ctrs, "Get Comm. Event Counters" }, + { get_comm_event_log, "Get Comm. Event Log" }, + { program_584_984, "Program (584/984)" }, + { poll_584_984, "Poll (584/984)" }, + { force_mult_coils, "Force Multiple Coils" }, + { write_mult_regs, "Write Multiple Registers" }, + { report_slave_id, "Report Slave ID" }, + { program_884_u84, "Program 884/u84" }, + { reset_comm_link, "Reset Comm. Link (884/u84)" }, + { read_genl_ref, "Read General Reference" }, + { write_genl_ref, "Write General Reference" }, + { mask_write_reg, "Mask Write Register" }, + { read_write_reg, "Read Write Register" }, + { read_fifo_queue, "Read FIFO Queue" }, + { program_ConCept, "Program (ConCept)" }, + { firmware_replace, "Firmware replacement" }, + { program_584_984_2, "Program (584/984)" }, + { report_local_addr_mb, "Report local address (Modbus)" }, + { 0, NULL } +}; + +static const value_string exception_code_vals[] = { + { illegal_function, "Illegal function" }, + { illegal_address, "Illegal data address" }, + { illegal_value, "Illegal data value" }, + { illegal_response, "Illegal response length" }, + { acknowledge, "Acknowledge" }, + { slave_busy, "Slave device busy" }, + { negative_ack, "Negative acknowledge" }, + { memory_err, "Memory parity error" }, + { gateway_unavailable, "Gateway path unavailable" }, + { gateway_trgt_fail, "Gateway target device failed to respond" }, + { 0, NULL } +}; + +/* Code to actually dissect the packets */ +static void +dissect_mbtcp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) +{ +/* Set up structures needed to add the protocol subtree and manage it */ + mbtcp_hdr mh; + proto_item *mi, *mf; + proto_tree *mbtcp_tree, *modbus_tree, *group_tree; + int offset, group_offset, packet_type; + guint i; + gint packet_len, payload_start, payload_len; + char *func_string = "", pkt_type_str[9] = ""; + char err_str[100] = ""; + guint32 byte_cnt, group_byte_cnt, group_word_cnt; + guint32 packet_num; /* num to uniquely identify different mbtcp + * packets in one TCP packet */ + guint8 exception_code; + gboolean exception_returned; + +/* Make entries in Protocol column on summary display */ + if (check_col(pinfo->cinfo, COL_PROTOCOL)) + col_set_str(pinfo->cinfo, COL_PROTOCOL, "Modbus/TCP"); + + if (check_col(pinfo->cinfo, COL_INFO)) + col_clear(pinfo->cinfo, COL_INFO); + +/* Make entries in Info column on summary display */ + offset = 0; + tvb_memcpy(tvb, (guint8 *)&mh, offset, sizeof(mbtcp_hdr)); + mh.transaction_id = g_ntohs(mh.transaction_id); + mh.protocol_id = g_ntohs(mh.protocol_id); + mh.len = g_ntohs(mh.len); + if ( mh.mdbs_hdr.function_code & 0x80 ) { + exception_code = tvb_get_guint8(tvb, offset + sizeof(mbtcp_hdr)); + mh.mdbs_hdr.function_code ^= 0x80; + exception_returned = TRUE; + } + else { + exception_code = 0; + exception_returned = FALSE; + } + func_string = val_to_str(mh.mdbs_hdr.function_code, function_code_vals, + "Unknown function (%u)"); + if (check_col(pinfo->cinfo, COL_INFO)) + { + packet_type = classify_packet(pinfo); + switch ( packet_type ) { + case query_packet : strcpy(pkt_type_str, "query"); + break; + case response_packet : strcpy(pkt_type_str, "response"); + break; + case cannot_classify : strcpy(err_str, "Unable to classify as query or response."); + strcpy(pkt_type_str, "unknown"); + break; + default : + break; + } + if ( exception_returned ) + strcpy(err_str, "Exception returned "); + col_add_fstr(pinfo->cinfo, COL_INFO, + "%8s [%2u pkt(s)]: trans: %5u; unit: %3u, func: %3u: %s. %s", + pkt_type_str, 1, mh.transaction_id, (unsigned char) mh.mdbs_hdr.unit_id, + (unsigned char) mh.mdbs_hdr.function_code, func_string, err_str); + } + + /* build up protocol tree and iterate over multiple packets */ + packet_num = 0; + while (1) { + packet_type = classify_packet(pinfo); + packet_len = sizeof(mbtcp_hdr) - sizeof(modbus_hdr) + mh.len; + + /* if a tree exists, perform operations to add fields to it */ + if (tree) { + mi = proto_tree_add_protocol_format(tree, proto_mbtcp, tvb, offset, + packet_len, "Modbus/TCP"); + mbtcp_tree = proto_item_add_subtree(mi, ett_mbtcp); + + /* Add items to protocol tree specific to Modbus/TCP Modbus/TCP */ + proto_tree_add_uint(mbtcp_tree, hf_mbtcp_transid, tvb, offset, 2, + mh.transaction_id); + proto_tree_add_uint(mbtcp_tree, hf_mbtcp_protid, tvb, offset + 2, 2, + mh.protocol_id); + proto_tree_add_uint(mbtcp_tree, hf_mbtcp_len, tvb, offset + 4, 2, + mh.len); + + /* Add items to protocol tree specific to Modbus generic */ + mf = proto_tree_add_text(mbtcp_tree, tvb, offset + 6, mh.len, + "Modbus"); + modbus_tree = proto_item_add_subtree(mf, ett_modbus_hdr); + proto_tree_add_uint(modbus_tree, hf_mbtcp_unitid, tvb, offset + 6, 1, + mh.mdbs_hdr.unit_id); + mi = proto_tree_add_uint(modbus_tree, hf_mbtcp_functioncode, tvb, offset + 7, 1, + mh.mdbs_hdr.function_code); + + /** detail payload as a function of exception/function code */ + func_string = val_to_str(mh.mdbs_hdr.function_code, + function_code_vals, "Unknown function"); + payload_start = offset + 8; + payload_len = mh.len - sizeof(modbus_hdr); + if (exception_returned) { + proto_item_set_text(mi, "function %u: %s. Exception: %s", + mh.mdbs_hdr.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", mh.mdbs_hdr.function_code, + func_string); + switch (mh.mdbs_hdr.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, FALSE); + proto_tree_add_item(modbus_tree, hf_modbus_bitcnt, tvb, payload_start + 2, 2, FALSE); + } + 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); + proto_tree_add_text(modbus_tree, tvb, payload_start + 1, byte_cnt, "Data"); + } + 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, FALSE); + proto_tree_add_item(modbus_tree, hf_modbus_wordcnt, tvb, payload_start + 2, 2, FALSE); + } + 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); + proto_tree_add_text(modbus_tree, tvb, payload_start + 1, byte_cnt, "Data"); + } + break; + + case write_coil: + if (packet_type == query_packet) { + proto_tree_add_item(modbus_tree, hf_modbus_reference, tvb, payload_start, 2, FALSE); + proto_tree_add_text(modbus_tree, tvb, payload_start + 2, 1, "Data"); + 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, FALSE); + proto_tree_add_text(modbus_tree, tvb, payload_start + 2, 1, "Data"); + 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, FALSE); + proto_tree_add_text(modbus_tree, tvb, payload_start + 2, 2, "Data"); + } + else if (packet_type == response_packet) { + proto_tree_add_item(modbus_tree, hf_modbus_reference, tvb, payload_start, 2, FALSE); + proto_tree_add_text(modbus_tree, tvb, payload_start + 2, 2, "Data"); + } + break; + + case read_except_stat: + if (packet_type == response_packet) + proto_tree_add_text(modbus_tree, tvb, payload_start, 1, "Data"); + break; + + case force_mult_coils: + if (packet_type == query_packet) { + proto_tree_add_item(modbus_tree, hf_modbus_reference, tvb, payload_start, 2, FALSE); + proto_tree_add_item(modbus_tree, hf_modbus_bitcnt, tvb, payload_start + 2, 2, FALSE); + 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); + proto_tree_add_text(modbus_tree, tvb, payload_start + 5, byte_cnt, "Data"); + } + else if (packet_type == response_packet) { + proto_tree_add_item(modbus_tree, hf_modbus_reference, tvb, payload_start, 2, FALSE); + proto_tree_add_item(modbus_tree, hf_modbus_bitcnt, tvb, payload_start + 2, 2, FALSE); + } + break; + + case write_mult_regs: + if (packet_type == query_packet) { + proto_tree_add_item(modbus_tree, hf_modbus_reference, tvb, payload_start, 2, FALSE); + proto_tree_add_item(modbus_tree, hf_modbus_wordcnt, tvb, payload_start + 2, 2, FALSE); + 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); + proto_tree_add_text(modbus_tree, tvb, payload_start + 5, byte_cnt, "Data"); + } + else if (packet_type == response_packet) { + proto_tree_add_item(modbus_tree, hf_modbus_reference, tvb, payload_start, 2, FALSE); + proto_tree_add_item(modbus_tree, hf_modbus_wordcnt, tvb, payload_start + 2, 2, FALSE); + } + break; + + case read_genl_ref: + 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, FALSE); + proto_tree_add_item(group_tree, hf_modbus_lreference, tvb, group_offset + 1, 4, FALSE); + proto_tree_add_item(group_tree, hf_modbus_wordcnt, tvb, group_offset + 5, 2, FALSE); + 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, FALSE); + proto_tree_add_text(group_tree, tvb, group_offset + 2, group_byte_cnt - 1, "Data"); + group_offset += (group_byte_cnt + 1); + byte_cnt -= (group_byte_cnt + 1); + i++; + } + } + break; + + case write_genl_ref: + 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, FALSE); + proto_tree_add_item(group_tree, hf_modbus_lreference, tvb, group_offset + 1, 4, FALSE); + proto_tree_add_uint(group_tree, hf_modbus_wordcnt, tvb, group_offset + 5, 2, + group_word_cnt); + proto_tree_add_text(group_tree, tvb, group_offset + 7, group_byte_cnt - 7, "Data"); + 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, FALSE); + proto_tree_add_item(modbus_tree, hf_modbus_andmask, tvb, payload_start + 2, 2, FALSE); + proto_tree_add_item(modbus_tree, hf_modbus_ormask, tvb, payload_start + 4, 2, FALSE); + } + break; + + case read_write_reg: + if (packet_type == query_packet) { + proto_tree_add_item(modbus_tree, hf_modbus_readref, tvb, payload_start, 2, FALSE); + proto_tree_add_item(modbus_tree, hf_modbus_readwordcnt, tvb, payload_start + 2, 2, FALSE); + proto_tree_add_item(modbus_tree, hf_modbus_writeref, tvb, payload_start + 4, 2, FALSE); + proto_tree_add_item(modbus_tree, hf_modbus_writewordcnt, tvb, payload_start + 6, 2, FALSE); + 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); + proto_tree_add_text(modbus_tree, tvb, payload_start + 9, byte_cnt, "Data"); + } + 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); + proto_tree_add_text(modbus_tree, tvb, payload_start + 1, byte_cnt, "Data"); + } + break; + + case read_fifo_queue: + if (packet_type == query_packet) + proto_tree_add_item(modbus_tree, hf_modbus_reference, tvb, payload_start, 2, FALSE); + 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, FALSE); + proto_tree_add_text(modbus_tree, tvb, payload_start + 4, byte_cnt - 2, "Data"); + } + break; + + case diagnostics: + case program_484: + case poll_484: + case get_comm_event_ctrs: + case get_comm_event_log: + case program_584_984: + case poll_584_984: + case report_slave_id: + case program_884_u84: + case reset_comm_link: + case program_ConCept: + case firmware_replace: + case program_584_984_2: + case report_local_addr_mb: + /* these function codes are not part of the Modbus/TCP specification */ + default: + if (payload_len > 0) + proto_tree_add_text(modbus_tree, tvb, payload_start, payload_len, "Data"); + break; + } + } + } + + /* move onto next packet (if there) */ + offset += packet_len; + packet_num++; + if (tvb_reported_length_remaining(tvb, offset) > 0) { + + /* load header structure for next packet */ + tvb_memcpy(tvb, (guint8 *)&mh, offset, sizeof(mbtcp_hdr)); + mh.transaction_id = g_ntohs(mh.transaction_id); + mh.protocol_id = g_ntohs(mh.protocol_id); + mh.len = g_ntohs(mh.len); + + if ( mh.mdbs_hdr.function_code & 0x80 ) { + exception_code = tvb_get_guint8(tvb, offset + sizeof(mbtcp_hdr)); + mh.mdbs_hdr.function_code ^= 0x80; + exception_returned = TRUE; + } else + exception_returned = FALSE; + } + else + break; + } +} + + +/* Register the protocol with Ethereal */ + +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", "modbus_tcp.trans_id", + FT_UINT16, BASE_DEC, NULL, 0x0, + "", HFILL } + }, + { &hf_mbtcp_protid, + { "protocol identifier", "modbus_tcp.prot_id", + FT_UINT16, BASE_DEC, NULL, 0x0, + "", HFILL } + }, + { &hf_mbtcp_len, + { "length", "modbus_tcp.len", + FT_UINT16, BASE_DEC, NULL, 0x0, + "", HFILL } + }, + /* Modbus header fields */ + { &hf_mbtcp_unitid, + { "unit identifier", "modbus_tcp.unit_id", + FT_UINT8, BASE_DEC, NULL, 0x0, + "", HFILL } + }, + { &hf_mbtcp_functioncode, + { "function code", "modbus_tcp.func_code", + FT_UINT8, BASE_DEC, VALS(function_code_vals), 0x0, + "", HFILL } + }, + { &hf_modbus_reference, + { "reference number", "modbus_tcp.reference_num", + FT_UINT16, BASE_DEC, NULL, 0x0, + "", HFILL } + }, + { &hf_modbus_lreference, + { "reference number (32 bit)", "modbus_tcp.reference_num_32", + FT_UINT32, BASE_DEC, NULL, 0x0, + "", HFILL } + }, + { &hf_modbus_reftype, + { "reference type", "modbus_tcp.reference_type", + FT_UINT8, BASE_DEC, NULL, 0x0, + "", HFILL } + }, + { &hf_modbus_readref, + { "read reference number", "modbus_tcp.read_reference_num", + FT_UINT16, BASE_DEC, NULL, 0x0, + "", HFILL } + }, + { &hf_modbus_writeref, + { "write reference number", "modbus_tcp.write_reference_num", + FT_UINT16, BASE_DEC, NULL, 0x0, + "", HFILL } + }, + { &hf_modbus_wordcnt, + { "word count", "modbus_tcp.word_cnt", + FT_UINT16, BASE_DEC, NULL, 0x0, + "", HFILL } + }, + { &hf_modbus_readwordcnt, + { "read word count", "modbus_tcp.read_word_cnt", + FT_UINT16, BASE_DEC, NULL, 0x0, + "", HFILL } + }, + { &hf_modbus_writewordcnt, + { "write word count", "modbus_tcp.write_word_cnt", + FT_UINT16, BASE_DEC, NULL, 0x0, + "", HFILL } + }, + { &hf_modbus_bitcnt, + { "bit count", "modbus_tcp.bit_cnt", + FT_UINT16, BASE_DEC, NULL, 0x0, + "", HFILL } + }, + { &hf_modbus_bytecnt, + { "byte count", "modbus_tcp.byte_cnt", + FT_UINT8, BASE_DEC, NULL, 0x0, + "", HFILL } + }, + { &hf_modbus_lbytecnt, + { "byte count (16-bit)", "modbus_tcp.byte_cnt_16", + FT_UINT8, BASE_DEC, NULL, 0x0, + "", HFILL } + }, + { &hf_modbus_exceptioncode, + { "exception code", "modbus_tcp.exception_code", + FT_UINT8, BASE_DEC, VALS(exception_code_vals), 0x0, + "", HFILL } + }, + { &hf_modbus_andmask, + { "AND mask", "modbus_tcp.and_mask", + FT_UINT16, BASE_HEX, NULL, 0x0, + "", HFILL } + }, + { &hf_modbus_ormask, + { "OR mask", "modbus_tcp.or_mask", + FT_UINT16, BASE_HEX, NULL, 0x0, + "", HFILL } + } + }; + + /* Setup protocol subtree array */ + static gint *ett[] = { + &ett_mbtcp, + &ett_modbus_hdr, + &ett_group_hdr + }; + + /* Register the protocol name and description */ + proto_mbtcp = proto_register_protocol("Modbus/TCP", "Modbus/TCP", "mbtcp"); + + /* 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; + + mbtcp_handle = create_dissector_handle(dissect_mbtcp, proto_mbtcp); + dissector_add("tcp.port", TCP_PORT_MBTCP, mbtcp_handle); +} |