On Wed, Aug 21, 2013 at 7:09 AM, Rakesh B.K <bk.rak...@ymail.com> wrote: > Hello, > > Found the bug in OpenVSwitch and below is the Description attaching a test > sample to reproduce the bug, > > Problem Description: > > I am facing a problem where OpenVSwitch is not complying with the RFC > 768 standard on calculating UDP checksum. According to the standard > (http://www.ietf.org/rfc/rfc768.txt), details on the UDP fields specify > that > > "If the computed checksum is zero, it is transmitted as all ones > (the equivalent in one's complement arithmetic)" > > In my case, I expect UDP checksum to be 0xffff, but I receive the > computed checksum as 0x0000. This happens in a VM communicating to external > network via OpenVSwitch. For checking this, I have used udp based test > program which is mentioned in the set-up below.
This may actually be a larger issue than just OVS, relating to the computation of UDP checksums in software instead of hardware. Can you try turning off hardware checksum offloading (using ethtool -K <eth> tx off) and see if the problem happens on all packets? If it does, then I suspect you can also reproduce the problem without OVS using this setting. _______________________________________________ discuss mailing list discuss@openvswitch.org http://openvswitch.org/mailman/listinfo/discuss
