On Fri, Jun 23, 2006 at 02:26:16PM -0700, Michael Chan wrote: > > This patch is more correct. Please ignore the previous one. > > [NET]: Fix CHECKSUM_HW GSO problems. > > Fix checksum problems in the GSO code path for CHECKSUM_HW packets. > > The ipv4 TCP pseudo header checksum has to be adjusted for GSO > segmented packets. > > Signed-off-by: Michael Chan <[EMAIL PROTECTED]>
Good catch. Obviously the only CHECKSUM_HW I tested was loop :) Looking at this again it seems that we can optimise it further so how about this? [NET]: Fix CHECKSUM_HW GSO problems. Fix checksum problems in the GSO code path for CHECKSUM_HW packets. The ipv4 TCP pseudo header checksum has to be adjusted for GSO segmented packets. The adjustment is needed because the length field in the pseudo-header changes. However, because we have the inequality oldlen > newlen, we know that delta = (u16)~oldlen + newlen is still a 16-bit quantity. This also means that htonl(delta) + th->check still fits in 32 bits. Therefore we don't have to use csum_add on this operations. This is based on a patch by Michael Chan <[EMAIL PROTECTED]>. Signed-off-by: Herbert Xu <[EMAIL PROTECTED]> Cheers, -- Visit Openswan at http://www.openswan.org/ Email: Herbert Xu ~{PmV>HI~} <[EMAIL PROTECTED]> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt -- diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 0e029c4..10f1a8c 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -2166,7 +2166,7 @@ struct sk_buff *tcp_tso_segment(struct s if (!pskb_may_pull(skb, thlen)) goto out; - oldlen = ~htonl(skb->len); + oldlen = (u16)~skb->len; __skb_pull(skb, thlen); segs = skb_segment(skb, sg); @@ -2174,7 +2174,7 @@ struct sk_buff *tcp_tso_segment(struct s goto out; len = skb_shinfo(skb)->gso_size; - delta = csum_add(oldlen, htonl(thlen + len)); + delta = htonl(oldlen + (thlen + len)); skb = segs; th = skb->h.th; @@ -2183,10 +2183,10 @@ struct sk_buff *tcp_tso_segment(struct s do { th->fin = th->psh = 0; - if (skb->ip_summed == CHECKSUM_NONE) { - th->check = csum_fold(csum_partial( - skb->h.raw, thlen, csum_add(skb->csum, delta))); - } + th->check = ~csum_fold(th->check + delta); + if (skb->ip_summed != CHECKSUM_HW) + th->check = csum_fold(csum_partial(skb->h.raw, thlen, + skb->csum)); seq += len; skb = skb->next; @@ -2196,11 +2196,11 @@ struct sk_buff *tcp_tso_segment(struct s th->cwr = 0; } while (skb->next); - if (skb->ip_summed == CHECKSUM_NONE) { - delta = csum_add(oldlen, htonl(skb->tail - skb->h.raw)); - th->check = csum_fold(csum_partial( - skb->h.raw, thlen, csum_add(skb->csum, delta))); - } + delta = htonl(oldlen + (skb->tail - skb->h.raw)); + th->check = ~csum_fold(th->check + delta); + if (skb->ip_summed != CHECKSUM_HW) + th->check = csum_fold(csum_partial(skb->h.raw, thlen, + skb->csum)); out: return segs; - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
