Subject: Re: UDP checksum broken since 2.6.18?

From: "Thomas B. Rücker" <[email-masked]>
Date: Wed, 23 May 2007 10:33:16 +0000

Herbert Xu wrote:
> "Thomas B. R??cker" <[email-masked]> wrote:
>   
>> Stephen Hemminger wrote:
>>     
>>> The packet passed to packet capture programs may not have a valid checksum
>>> if you have checksum offload configured on the device.  What kind of hardware
>>> do you have on sender and receiver? 
>>>       
>> The c-snippet uses 127.x.x.x --> loopback
>>     
>
> We never compute the complete checksum for loopback so that explains
> the bogus checksum.
>   
Does this also explain why wireshark thinks the checksum is right when
tested on <=2.6.17?

Cheers

Thomas