Wireshark mailing list archives
Disabling a dissector doesn't seem to quite work.
From: "Maynard, Chris" <Christopher.Maynard () GTECH COM>
Date: Fri, 7 Sep 2012 17:47:43 -0400
Recently another old proprietary protocol (I'll call it FOO) was brought to my attention, and I was asked to write a dissector for it. In doing so, I discovered a conflict with another dissector, namely SNA. Initially I thought that simply disabling SNA when analyzing FOO would be good enough for our purposes; however, even after disabling SNA, the FOO dissector was never called. The conflict arises because both dissectors, SNA and FOO, register as follows: dissector_add_uint("llc.dsap", SAP_SNA2, [sna|foo]_handle); I found that even with SNA disabled, I had to comment out the above line of code from the packet-sna.c source file before LLC would successfully hand off dissection to FOO. To illustrate this, I've attached a very stripped down and slightly modified version of packet-foo.c, along with a simple foo24.pcap file in case anyone would care to take a look at it. I have since found an alternate solution, but I was surprised that disabling a protocol does not seem to have the completely desired effect. While the packet does not get dissected as SNA, other dissectors are apparently not given the opportunity to dissect the packet even when the SNA dissector is disabled. But beyond LLC and SNA, I was thinking/wondering that maybe this is a general problem affecting all dissectors and that some general solution might be needed? Thanks. - Chris -- CONFIDENTIALITY NOTICE: The information contained in this email message is intended only for use of the intended recipient. If the reader of this message is not the intended recipient, you are hereby notified that any dissemination, distribution or copying of this communication is strictly prohibited. If you have received this communication in error, please immediately delete it from your system and notify the sender by replying to this email. Thank you.
Attachment:
packet-foo.c
Description: packet-foo.c
Attachment:
foo24.pcap
Description: foo24.pcap
Attachment:
Makefile_common.patch
Description: Makefile_common.patch
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Current thread:
- Disabling a dissector doesn't seem to quite work. Maynard, Chris (Sep 07)
- Re: Disabling a dissector doesn't seem to quite work. Evan Huus (Sep 07)
- Re: Disabling a dissector doesn't seem to quite work. Evan Huus (Sep 08)
- Re: [Wireshark-dev] Disabling a dissector doesn't seem to quite work. Christopher Maynard (Sep 15)
- Re: Disabling a dissector doesn't seem to quite work. Guy Harris (Sep 15)
- Re: Disabling a dissector doesn't seem to quite work. Joerg Mayer (Sep 16)
- Re: Disabling a dissector doesn't seem to quite work. Guy Harris (Sep 16)
- Re: Disabling a dissector doesn't seem to quite work. Joerg Mayer (Sep 17)
- Re: Disabling a dissector doesn't seem to quite work. Evan Huus (Sep 08)
- Re: Disabling a dissector doesn't seem to quite work. Evan Huus (Sep 07)
- Re: [Wireshark-dev] Disabling a dissector doesn't seem to quite work. Christopher Maynard (Sep 15)
- Re: Disabling a dissector doesn't seem to quite work. Evan Huus (Sep 15)
- Re: Disabling a dissector doesn't seem to quite work. Bill Meier (Sep 15)