On Tue, Dec 8, 2015 at 5:56 PM, Thomas Graf <tg...@suug.ch> wrote: > On 12/08/15 at 09:04am, Tom Herbert wrote: >> There are other reasons why CHECKSUM_COMPLETE is preferable: >> >> - CHECKSUM_COMPLETE is more robust. We have no way to validate that >> the device is actually correct in CHECKSUM_UNNECESSARY. For instance, >> how do we know that there isn't some failure in the device where >> everything is being marked as good even if it's not. With >> CHECKSUM_COMPLETE it is the host that actually makes the decision of >> whether the checksum is correct it is highly unlikely that failing >> checksum calculation on the device won't be detected. HW failures and >> bugs are real concern. >> - CHECKSUM_UNNECESSARY does not report bad checksums. There is a >> csum_bad flag in the sk_buff that could be set if the driver detects a >> bad checksum in the packet, but no drivers seem to be setting that >> currently. So for any packets with bad checksums the stack will need >> to compute the checksum itself, so this potentially becomes the basis >> of a DDOS attack. CHECKSUM_COMPLETE does not have this problem, we get >> the checksum of the packet rather the checksum is correct or not. > > If I understood Edward correctly, his proposal would be for the > card to provide both, the csum as for CHECKSUM_COMPLETE plus the > validation yes/no hint. It would be up to the kernel to decide > whether to validate itself or trust the card. > > I'm all in favour CHECKSUM_COMPLETE as the only way to go but > we should be aware that it depends on the penetration of RCO in > hardware VTEPs.
Thomas, I don't understand what you are saying here. CHECKSUM_COMPLETE is an interface for drivers providing the computed checksum of a packet on receive, how is this dependent on any use case or any other mechanisms? -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
