Stephan Gatzka wrote: > >> "Off-link source" means the source exists on the different L2 >> network. In other words, source is connected via router(s). >> >> ethernet firewire >> Host -------------- Router ------------ Host >> > > O.k., understood. But the receiving router verifies the checksum of incoming > packets and sends them on the firewire link. On firewire we have CRC > checksums to ensure the integrity of packets. > > I agree with your patch but I don't see why we should check them in the > driver. I thought your patch will ensure that the checksums will be verified > in the upper layers.
Routers do not inspect whole packet. For IPv4, we have IP checksum, but routers (usually) do not check upper-layer (e.g. UDP) checksum. For IPv6, we do not have IP checksum. CHECKSUM_UNNECESSARY means the driver has verified upper layer (e.g. TCP/UDP) checksum. Modern hardware can perform upper-layer checksumming as well. But of course, not all drivers are required to verify the upper-layer checksum; if the driver do not verify checksum in the packet, just say CHECKSUM_NONE. Regards, --yoshfuji -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
