Wireshark-users: [Wireshark-users] small bug in dissecting DHCPv4 relay suboptions
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From: Stefan Puiu <stefan.puiu@xxxxxxxxx>
Date: Thu, 25 Oct 2007 09:56:13 +0000 (UTC)
Hi all, 

I was capturing some DHCP relay to DHCP server traffic that uses some relay
suboptions (one of them being suboption 6, see RFC 3993) using tcpdump on Linux.
When I loaded the capture file in wireshark, noticed that suboption 6 is printed
as 'invalid agent suboption (6), 4 bytes', for example. Since I was checking a
DHCP relay implementation, I had to make sure that suboption6 is properly
encoded, so I had a look at the wireshark code (0.99.6, I'll also check svn
head) and noticed that any suboptions besides 1 (circuit id) and 2 (remote id)
are treated as invalid suboptions. It looks like there are suboptions up to 10
defined so far (see http://www.iana.org/assignments/bootp-dhcp-parameters). 

I'll try to come up with a patch against head, IMO the error message should at
least be 'Unknown agent suboption', and known suboptions should be printed. 

If needed, I can provide a capture file that exhibits the problem. 

Stefan.