Re: [RFT] nf_contrack_udp: handle packets with padding and hwchecksum

Hi Stephen,

On Fri, Feb 17, 2012 at 10:16:48AM -0800, Stephen Hemminger wrote:

If UDP packet with extra padding is received on a device that
does hardware checksumming (but not checking) is processed
by netfilter conntrack, it would generate a bogus warning
about the checksum being incorrect.

There were two possible solutions. The netfilter conntrack
code could trim the packet, discarding the extra padding
and adjusting the checksum. Or it can force regular
non-offloaded checksum. This patch implements the latter
on the principal that is better for firewall code to not
modify the packet.

I like this approach.

Compile tested only; haven't been able to reproduce the
problem yet.

Let me know if I should pass this to davem once you confirm this fixes
the problem you're noticing.