Wireshark mailing list archives
Re: Acp 142 checksum algorithm
From: Jaap Keuter <jaap.keuter () xs4all nl>
Date: Thu, 11 Dec 2014 21:41:46 +0100
Hi, Reading the document [3], section Evolution (105 and 106) suggest that a whole lot more was done to the protocol. I'm not sure if this has influenced the PDU's themselves (apart from the checksum as you indicated), a more rigorous analysis of the document would be required since no delta is described. The best way to get attention to this is to collect relevant sample capture files of the new protocol and open an enhancement bug in the Wireshark bugzilla (https://bugs.wireshark.org) and attach this description and the sample capture files there. If someone picks up this bug (s)he then has all the info they need to get started. However, the volunteer nature of this project does not provide guarantees if and when this is going to be done (although Stig might not be able to hold himself back ;) ). Thanks, Jaap On 12/10/2014 10:10 PM, Ricardo Cristian Ramirez wrote:
ACP 142 (PMul) protocol has two versions. The first one [1] was released at 2001 and the second one [2] was released at 2008. The first version suggests to use 8-bit Fletcher's algorithm, which produces 16 bit checksum. And, an implementation of this algorithm is provided in the specification. Current PMul dissector [3] of the Wireshark uses this provided algorithm. The checksum description in the second version was changed: Provided algorithm was removed and below statement is given without an algorithm: " The checksum field is the 16 bit one's complement of the one's complement sum of all 16 bit words in the header. " As far as I know, this statement decribes the TCP/IP checksum and an update is needed for PMul dissector. [1] jcs.dtic.mil/j6/cceb/acps/acp142/ACP142.pdf [2] jcs.dtic.mil/j6/cceb/acps/acp142/ACP142A.pdf [3] https://code.wireshark.org/review/gitweb?p=wireshark.git;a=blob;f=epan/dissectors/packet-p_mul.c;h=a03e69f10825e6dacb82f3aacb33b465adeb721a;hb=HEAD
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Current thread:
- Acp 142 checksum algorithm Ricardo Cristian Ramirez (Dec 10)
- Re: Acp 142 checksum algorithm Jaap Keuter (Dec 11)
- Re: Acp 142 checksum algorithm Stig Bjørlykke (Dec 11)
- Re: Acp 142 checksum algorithm Ricardo Cristian Ramirez (Dec 25)