Herbert Xu wrote: > Hi Patrick: > > On Wed, Jul 26, 2006 at 05:38:07AM +0200, Patrick McHardy wrote: > >>I have a patch which changes netfilter to do incremental checksumming. >>The hook number is passed to all functions doing this so they know >>how to update the checksum. Could you explain how >>CHECKSUM_COMPLETE/CHECKSUM_PARTIAL are going to be used? I assume >>they're meant to avoid passing hook numbers around everywhere? > > > Yes the hook number is another way to solve the same problem. However, > it can only be used within netfilter. CHECKSUM_COMPLETE/CHECKSUM_PARTIAL > on the other hand are valid throughout the stack. With Xen feeding Linux > packets into the stack the netfilter hook is also no longer sufficient to > distinguish between these two cases as partial checksum packets can now > appear on receive. > > The problem is that you need to do different incremental updates depending > on whether the checksum is complete (i.e., CHECKSUM_HW on receive), or > partial (i.e., CHECKSUM_HW on transmit). > > With complete checksums the current update code in netfilter can be used > as is. With partial checksums you need to exclude bits which weren't > used when computing the partial checksums (e.g., TCP port numbers need > to be excluded, but the IP address needs to be included for NAT).
That does sound better than the hook number approach. > I have a patch that adds CHECKSUM_COMPLETE/CHECKSUM_PARTIAL if you want > something to work from. Let me know if you want this and I'll bounce it > to you. Please send it, I'll update my patch based on that. Thanks. - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
