This is a portion of the patch supplied in bug 7902 (https://bugs.wireshark.org/bugzilla/show_bug.cgi?id=7902). Breaking the functionality up into smaller chunks.
This definitively breaks the Modbus dissection into 3 dissectors:
Modbus - real protocol PDU
Modbus/TCP - Encapsulation of Modbus over TCP (with a small header before PDU)
Modbus RTU - Originally an encapsulation of Modbus over serial (with smaller header + CRC), but can also be sent over TCP.
General cleanup/refactoring (including display filter names) based on the 3 dissectors.
Also included:
1. Enhanced dissection to include preferences for register data to be dissected as UINT16, UINT32 or FLOAT
2. Dynamic port registration
3. Additional fields now filterable
svn path=/trunk/; revision=45793
Modbus object support for CIP dissector
Support for the Modbus object within the CIP dissector. Essentially wraps the Modbus protocol within a CIP object.
Also included update to Modbus error code per
http://www.wireshark.org/lists/wireshark-dev/201111/msg00187.html
svn path=/trunk/; revision=40371
I made the following improvements to the Modbus/TCP dissector:
1. Implemented protocol to the latest specification (v1.1b). See
http://www.modbus.org/specs.php.
2. Upgraded to "tcp_dissect_pdus" instead of having the dissector do it
manually. This also provides TCP packet reassembly support.
3. Removed support for UDP port 502 because it's not supported by the protocol
specification. I believe "Decode As..." could be used in its place.
4. Added dissector support for the following function codes:
a) 8 - Diagnostics
b) 11 - Event Counter
c) 12 - Event Log
d) 43 - Encapsulation Transport (mostly for 43/14)
5. Removed support for function codes not in the protocol specification. None
of them were really being parsed, they just offered a "name" for the function
code.
6. Moved protocol #defines to header file for access from other dissectors. I
plan to have other dissectors use this, but one patch at a time.
7. Created "modbus" dissector that is accessible to other dissectors.
8. Renamed base "display filter name" to reflect PROTOABBREV.
I removed defines for value_strings, I think it's better to export the vaöue strings if needed.
https://bugs.wireshark.org/bugzilla/show_bug.cgi?id=5923
svn path=/trunk/; revision=37539
Michael Mann