Re: IGRP

[Guy Harris <guy () alum mit edu>]

On Apr 28, 2004, at 7:03 PM, Michael Richardson wrote:

> Hannes,
>   ipproto.c has IPPROTO_IGRP, but ipproto.h doens't define it.
>
> Is this supposed to be protocol=9 ("IGP"), which you have as
> IPPROTO_PIGP, or???

Actually, I made it IPPROTO_PIGP, not Hannes - that one's not his fault.

We used to have IPPROTO_IGMP as 9 and IPPROTO_EIGRP as 88; however, 
some BSDs have IPPROTO_PIGP as 9 and IPPROTO_IGRP as 88, and don't have 
IPPROTO_EIGRP at all, so IPPROTO_IGRP and IPPROTO_EIGRP both end up 
defined as 88, and print-ip.c doesn't compile because it has two "case" 
clauses with a value of 88.

I decided to have IPPROTO_PIGP be 9 and IPPROTO_EIGRP as 88, as the 
current IANA protocol number assignments page says 9 is "any private 
interior gateway (used by Cisco for their IGRP)" and 88 is "EIGRP" from 
Cisco; so 9 isn't *explicitly* IGRP but 88 *is* explicitly EIGRP (not 
IGRP).

That fixed the compilation problem on OS X 10.3.3 (which is one of the 
BSDs in question), but ipproto.c continued to compile because OS X 
(like the other BSDs) defines IPPROTO_IGRP (as 88) - but it fails on 
OSes that don't define IPPROTO_IGRP.

The "temporary patch" Michael checked in is, in fact, the correct fix.

That raises another question, though - "print-ip.c" now treats both 
protocol 9 and protocol 88 as IGRP, but the packet formats are, I 
think, different - should we *only* treat IPPROTO_PIGP as IGRP, and 
handle IPPROTO_EIGRP either not at all or with an "eigrp_print()" 
routine?

(BTW, I'm sending this to tcpdump-workers () lists tcpdump org - if it 
doesn't make it to the list, that might be because of the check for 
headers that are too long, as I'm mailing it from work.  I had to 
shuffle the addresses around, as the reply-to address is still 
tcpdump-workers () lists sandelman ca - perhaps that no longer bounces, 
but it's bounced in the past.

I'm CCing Michael as well as Hannes on this; Michael, if this doesn't 
make it to the list, you might want to configure the mail software 
either to have a higher limit on the number of headers or not to count 
"Received:" headers against the quota.)

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