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Add "Modbus/TCP over UDP" 

There already is "ModbusRTU over UDP", this is the Modbus/TCP format over UDP.

Bug: 12768
Change-Id: I883aa8e88f8a1640459115434be84354e22bb361
Reviewed-on: https://code.wireshark.org/review/17215
Reviewed-by: Michael Mann <mmann78@netscape.net>
Petri-Dish: Michael Mann <mmann78@netscape.net>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Anders Broman <a.broman58@gmail.com>
This commit is contained in:
Michael Mann 2016-08-21 18:04:42 -04:00 committed by Anders Broman
parent 3aac4b1549
commit 6a7d5df1ae
1 changed files with 43 additions and 8 deletions
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51
epan/dissectors/packet-mbtcp.c
View File

@ -77,6 +77,7 @@ void proto_reg_handoff_mbrtu(void);
/* Initialize the protocol and registered fields */
static int proto_mbtcp = -1;
static int proto_mbudp = -1;
static int proto_mbrtu = -1;
static int proto_modbus = -1;
static int hf_mbtcp_transid = -1;
@ -163,6 +164,7 @@ static expert_field ei_mbtcp_cannot_classify = EI_INIT;
static dissector_handle_t modbus_handle;
static dissector_handle_t mbtcp_handle;
static dissector_handle_t mbudp_handle;
static dissector_handle_t mbrtu_handle;
static dissector_table_t modbus_data_dissector_table;
@ -391,7 +393,7 @@ static const enum_val_t mbus_register_format[] = {
/* Code to dissect Modbus/TCP packets */
static int
dissect_mbtcp_pdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
dissect_mbtcp_pdu_common(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, int proto)
{
/* Set up structures needed to add the protocol subtree and manage it */
proto_item *mi;
@ -404,10 +406,6 @@ dissect_mbtcp_pdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* dat
guint16 transaction_id, protocol_id, len;
guint8 unit_id, function_code, exception_code, subfunction_code;
/* 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);
@ -490,8 +488,7 @@ dissect_mbtcp_pdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* dat
}
/* Create protocol tree */
mi = proto_tree_add_protocol_format(tree, proto_mbtcp, tvb, offset,
len+6, "Modbus/TCP");
mi = proto_tree_add_item(tree, proto, tvb, offset, len+6, ENC_NA);
mbtcp_tree = proto_item_add_subtree(mi, ett_mbtcp);
if (packet_type == CANNOT_CLASSIFY)
@ -513,6 +510,16 @@ dissect_mbtcp_pdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* dat
return tvb_captured_length(tvb);
}
static int
dissect_mbtcp_pdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
{
/* Make entries in Protocol column on summary display */
col_set_str(pinfo->cinfo, COL_PROTOCOL, "Modbus/TCP");
col_clear(pinfo->cinfo, COL_INFO);
return dissect_mbtcp_pdu_common(tvb, pinfo, tree, proto_mbtcp);
}
/* Code to dissect Modbus RTU over TCP packets */
static int
dissect_mbrtu_pdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
@ -757,6 +764,31 @@ dissect_mbtcp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data)
return tvb_captured_length(tvb);
}
static int
dissect_mbudp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
{
/* Make sure there's at least enough data to determine it's a Modbus UDP 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;
}
/* Make entries in Protocol column on summary display */
col_set_str(pinfo->cinfo, COL_PROTOCOL, "Modbus/UDP");
col_clear(pinfo->cinfo, COL_INFO);
return dissect_mbtcp_pdu_common(tvb, pinfo, tree, proto_mbudp);
}
/* Code to dissect Modbus RTU over TCP messages */
static int
dissect_mbrtu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data)
@ -1929,6 +1961,7 @@ proto_register_modbus(void)
/* Register the protocol name and description */
proto_mbtcp = proto_register_protocol("Modbus/TCP", "Modbus/TCP", "mbtcp");
proto_mbudp = proto_register_protocol("Modbus/UDP", "Modbus/UDP", "mbudp");
proto_mbrtu = proto_register_protocol("Modbus RTU", "Modbus RTU", "mbrtu");
proto_modbus = proto_register_protocol("Modbus", "Modbus", "modbus");
@ -1936,6 +1969,7 @@ proto_register_modbus(void)
modbus_handle = register_dissector("modbus", dissect_modbus, proto_modbus);
mbtcp_handle = register_dissector("mbtcp", dissect_mbtcp, proto_mbtcp);
mbrtu_handle = register_dissector("mbrtu", dissect_mbrtu, proto_mbrtu);
mbudp_handle = register_dissector("mbudp", dissect_mbudp, proto_mbudp);
/* Registering subdissectors table */
modbus_data_dissector_table = register_dissector_table("modbus.data", "Modbus Data", proto_modbus, FT_STRING, BASE_NONE, DISSECTOR_TABLE_NOT_ALLOW_DUPLICATE);
@ -2015,13 +2049,14 @@ proto_reg_handoff_mbtcp(void)
static unsigned int mbtcp_port;
/* Make sure to use Modbus/TCP Preferences field to determine default TCP port */
if(mbtcp_port != 0 && mbtcp_port != global_mbus_tcp_port){
dissector_delete_uint("tcp.port", mbtcp_port, mbtcp_handle);
dissector_delete_uint("udp.port", mbtcp_port, mbudp_handle);
}
if(global_mbus_tcp_port != 0 && mbtcp_port != global_mbus_tcp_port) {
dissector_add_uint("tcp.port", global_mbus_tcp_port, mbtcp_handle);
dissector_add_uint("udp.port", global_mbus_tcp_port, mbudp_handle);
}
mbtcp_port = global_mbus_tcp_port;