Ethereal-dev: [Ethereal-dev] dissecting only in one direction? (when src port matches protocol

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From: Ron Rechenmacher <ron@xxxxxxxxxxxxxxx>
Date: Sun, 05 Mar 2006 02:22:40 -0600
Hi,
I want to dissect a tcp protocol that is attached to a specific port, say 1234.
I went through the example in 
   http://ethereal.hostingzero.com/docs/edg_html/#ChapterDissection
and looked at doc/README.plugins

I've got something working, but only in one direction (see ouput below). I've 
been looking through the "web of info" for the past 2 hours and can't figure 
how to get ethereal to dissect packets with a _destination_ port that matches 
a particular
port specified in my dissector plugin via:
    dissector_add( "tcp.port", global_foo_port, foo_handle );

I've seen http://www.ethereal.com/faq.html#q11.3
and tried the "right click" thing and that doesn't work.

I tried searching through all the source for "dissector_" to see of I could 
get a clue as to what I'm doing wrong, but I ... do not have a clue :(

I'm built from ethereal-0.10.14.tgz on a redhat linux distribution.
Maybe my build is somehow bad --- does anyone have an idea of how to 
check/debug the fundamental the port matching?  I can't see where both the 
source and destination ports are checked.

Any ideas. Please help.
Thanks,
Ron

/root
ron :^| tethereal -i lo -c 8 port 1234
Capturing on lo
1   0.000000    127.0.0.1 -> 127.0.0.1    FOO Type (0x0001)
2   0.001285    127.0.0.1 -> 127.0.0.1    FOO Type (0x0001)
3   0.001527    127.0.0.1 -> 127.0.0.1    TCP 49879 > 1234 [ACK] ...
4   0.001921    127.0.0.1 -> 127.0.0.1    FOO Type (0x0001)
5   0.002204    127.0.0.1 -> 127.0.0.1    TCP 49879 > 1234 [ACK] ...
6   0.002474    127.0.0.1 -> 127.0.0.1    FOO Type (0x0001)
7   0.002738    127.0.0.1 -> 127.0.0.1    FOO Type (0x0001)
8   0.002973    127.0.0.1 -> 127.0.0.1    FOO Type (0x0001)