Peter M. Groen / libmodbus

Commit ddb2200377565bd8da694e125c4e89e415b15749

Authored by Stéphane Raimbault
1 parent 3c459bc1

Fix unit identifier not copied by the TCP server 

Reported by Antti Manninen and according to Page6 in the document
"MODBUS Messaging on TCP/IP Implementation Guide V1.0b",
------------------------
Unit Identifier – This field is used for intra-system routing purpose.
It is typically used to communicate to a MODBUS+ or a MODBUS serial
line slave through a gateway between an Ethernet TCP-IP network and
a MODBUS serial line. This field is set by the MODBUS Client in the
request and must be returned with the same value in the response by
the server.
------------------------
Inline Side-by-side
Showing 2 changed files with 5 additions and 2 deletions
1 -libmodbus 2.9.3 (2010-12-XX) 1 +libmodbus 2.9.3 (2011-01-XX)
2 ============================ 2 ============================
3 3
  4 +- Fix unit identifier not copied by the TCP server.
  5 + Reported by Antti Manninen.
4 - New function to reply to an indication with an exception message 6 - New function to reply to an indication with an exception message
5 modbus_reply_exception() 7 modbus_reply_exception()
6 - Fix missing modbus_flush() in unit tests 8 - Fix missing modbus_flush() in unit tests
src/modbus-tcp.c
  View file @ddb2200
@@ -141,7 +141,8 @@ int _modbus_tcp_build_response_basis(sft_t *sft, uint8_t *rsp) @@ -141,7 +141,8 @@ int _modbus_tcp_build_response_basis(sft_t *sft, uint8_t *rsp)
141 141
142 /* Length will be set later by send_msg (4 and 5) */ 142 /* Length will be set later by send_msg (4 and 5) */
143 143
144 - rsp[6] = 0xFF; 144 + /* The slave ID is copied from the indication */
  145 + rsp[6] = sft->slave;
145 rsp[7] = sft->function; 146 rsp[7] = sft->function;
146 147
147 return _MODBUS_TCP_PRESET_RSP_LENGTH; 148 return _MODBUS_TCP_PRESET_RSP_LENGTH;