Re: cvs commit: squid/src cf.data.pre wccp2.c

From: Reuben Farrelly <reuben-squid-dev@dont-contact.us>
Date: Thu, 25 May 2006 17:12:42 +1200

Hi Paul,

On 25/05/2006 8:02 a.m., Paul P Komkoff Jr wrote:
> Replying to Henrik Nordstrom:
>
> Be advised, that you can encounter unexpected difficulties with wccp
> protocol starting from linux kernel 2.6.16. In this kernel code path
> which assings IP ID to UDP packets was changed; IP ID on packets
> leaving from unconnected datagram socket with DF set is always 0.
>
> Cisco ios 12.4.7 and 12.4.8 (and I assume that all previous versions
> too) threating these packets as duplicates, and ingnores all except
> the first HIA.

I'll test this assumption out tonight. I am running 12.4(6)T2 at the moment and
seeing that problem. I'll do some more testing tonight on this with some older
mainline software on a 1721.

> I've implemented a workaround here. For the first time, I thought I
> can use n+1 sockets - one for each router in the view for sending, and
> another one bound to local port 2048 - for receiving. But after some
> initial testing I've discovered Cisco IOS violating not only
> ancient RFCs (RFC791) but it violates Cisco's own draft.

Did you open a case up with the TAC about this? If so, what was the case
number? My router is under maintenance so I've the option of doing that if you
haven't already tried to....however my past experience is that the frontline TAC
people often tend to shy away once you start talking third party (ie non cisco)
software.....

If it is an RFC compliance problem in IOS it would be good to get this fixed
going forward, I guess. Or at least have it documented.

reuben
Received on Wed May 24 2006 - 23:12:51 MDT

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