Re: Are "skb->data" physically continuous?

[Bluesea (big_bluesea@yahoo.com)]

--- Nick Patavalis <npat@xxxxxxxxxxxxxxxxxxxx> wrote:
> What I'm not sure about is whether the kernel or the
> hardware does the
> IP-header checksum calculation

The kernel calculate IP-header checksum in both Rx and
Tx path.

In kernel 2.4.22, 
Rx path, ip_rcv() calls ip_fast_csum() to calculate
and verify IP header checksum (ip_input.c, line 418);
Tx path, ip_queue_xmit2() calls ip_send_check(iph) to
add IP header checksum (ip_output.c, line 317).

In kernel 2.6.0-test2
Rx path, ip_rcv() calls ip_fast_csum() to calculate
and verify IP header checksum (ip_input.c, line 404);
Tx path, ip_queue_xmit() calls ip_send_check(iph) to
add IP header checksum (ip_output.c, line 383).

Bluesea


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