Maxim Khitrov <[email protected]> wrote: > What did surprise me is that netstat -ss (output below) shows that all > received packets were hardware-checksummed, but this value is 0 for > sent packets. Does this mean that ix supports checksum offloading, but > only for inbound packets?
Obviously, yes. That's exactly what this statistic means. > once I start testing forwarding performance. I assume that as long as > pf doesn't modify the packet (no nat/rdr, modulate state, scrubbing, > etc.), then there shouldn't be any need to recompute the checksum. Depends on the checksum. The pure forwarding case does not touch the TCP/UDP checksum, but it does change the IPv4 header checksum. That one is inexpensive, though, since it just covers the IPv4 header, which is already in the CPU cache. (IPv6 does not have a header checksum.) -- Christian "naddy" Weisgerber [email protected]
