Re: ip_wccp.c for WCCP v2 question

Oh, yeah... As for the negative size possibility. Maybe I'm misreading
it, but aren't they being dropped if there is a size problem (the two
'goto drop' bits)?

Is there harm in dropping them (as has always been done in the module)?
  I certainly don't have the knowledge to argue one way or the other. I
know just enough to figure out what the code is doing...not enough to
know what it /should/ do.

Thanks again for your input.

Henrik Nordstrom wrote:

> I am not yet familar with how Linux skb processing, but:
>
> One thing I notice is that you do not verify the size of the GRE packets
> before trying to grab the encapsulated one, so if the router sends you a
> bad WCCP packet (no encapsulated packet) then oops a negative packet
> size... Bbad WCCP packets has been seen from certain IOS versions in
> certain path configurations.
>
> and why is the module cleanup code removed?
>
> /Henrik
>
> Joe Cooper wrote:
>
>> Hi folks,
>>
>> We've got WCCP v2 working with Squid, thanks to some fast coding by
>> Kevin Wormington.
>>
>> Would someone (hopefully with more Linux kernel hacking knowledge than
>> I) take a look at this ip_wccp.c module:
>>
>> http://www.swelltech.com/pengies/joe/patches/ip_wccp.c
>>
>> It's only a couple of lines bigger than the original ip_wccp.c for v1 of
>> WCCP, where it checks for the extra 4 octets of the v2 GRE header and
>> then skips them for the decapsulation...but something is causing an oops
>> on our test box. We're not real sure exactly what is going on, but this
>> seems as likely a candidate as any, since the box doesn't crash until it
>> starts seeing WCCP traffic. Unfortunately...because Kevin's router only
>> has WCCP v2 and my router only has v1, we can't do any cross-testing.
>> And the Squid in testing has not yet been made both v2 and v1 aware (it
>> can currently do v2 just fine...but v1 is broken, I'll be fixing that
>> over the next few days).
>>
>> I'd welcome some comments from you guys, if you see anything problematic
>> in the module...
>> --
>> Joe Cooper <joe@swelltech.com>
>> Affordable Web Caching Proxy Appliances
>> http://www.swelltech.com

-- 
                                   --
                      Joe Cooper <joe@swelltech.com>
                  Affordable Web Caching Proxy Appliances
                         http://www.swelltech.com