--- "David S. Miller" <davem@redhat.com> wrote: > On Fri, 17 Oct 2003 13:17:56 -0700 (PDT) > Bluesea Yreen <big_bluesea@yahoo.com> wrote: > > > In "nf_hook_slow()" (netfilter.c), if > skb->ip_summed > > == CHECKSUM_HW and ouput interface is not NULL, > TCP > > checksum is calculated by calling > > "skb_checksum_help()". Why is this needed? > > Because it wants the packet in the exact state it > would be when it > hits the wire. > > > "nf_hook_slow" is called everytime a packet is > sent > > out, if "Network packet filtering debugging" is > chosen > > when compiling the kernel. Does this mean that > there > > is no TCP checksum offload feature in this > > circumstance? > > That's right, don't turn on debugging if you want > performance. > > BTW, this question really belongs on the netfilter > lists, you'd > get quicker and more intelligent responses there. > > Thanks. I posted my question in the netfilter list, but no one seems to be interested in it. So I have to turn back here to seek some help. :) Here goes my question: I found that if I install the netfilter, I cannot use TCP checksum offload feature. Because "nf_hook_slow" is called if there is any HOOK registered in the output path, and "skb->ip_summed" is set to "CHECKSUM_NONE" eventually. Am I right about that I cannot use TCP checksum offload feature if there is any HOOK registered in the output path? If it's right, how can I use TCP checksum offload feature while having the netfilter installed. Can I do it but disabling some netfilter options? Thank you, Bluesea __________________________________ Do you Yahoo!? The New Yahoo! Shopping - with improved product search http://shopping.yahoo.com - : send the line "unsubscribe linux-net" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
