tcp: gro: add checksuming helpers

skb with CHECKSUM_NONE cant currently be handled by GRO, and
we notice this deep in GRO stack in tcp[46]_gro_receive()

But there are cases where GRO can be a benefit, even with a lack
of checksums.

This preliminary work is needed to add GRO support
to tunnels.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2012-09-27 02:14:53 +00:00 committed by David S. Miller
parent 64c6d08e64
commit 861b650101
2 changed files with 33 additions and 6 deletions

View File

@ -2803,6 +2803,8 @@ void tcp4_proc_exit(void)
struct sk_buff **tcp4_gro_receive(struct sk_buff **head, struct sk_buff *skb)
{
const struct iphdr *iph = skb_gro_network_header(skb);
__wsum wsum;
__sum16 sum;
switch (skb->ip_summed) {
case CHECKSUM_COMPLETE:
@ -2811,11 +2813,22 @@ struct sk_buff **tcp4_gro_receive(struct sk_buff **head, struct sk_buff *skb)
skb->ip_summed = CHECKSUM_UNNECESSARY;
break;
}
/* fall through */
case CHECKSUM_NONE:
flush:
NAPI_GRO_CB(skb)->flush = 1;
return NULL;
case CHECKSUM_NONE:
wsum = csum_tcpudp_nofold(iph->saddr, iph->daddr,
skb_gro_len(skb), IPPROTO_TCP, 0);
sum = csum_fold(skb_checksum(skb,
skb_gro_offset(skb),
skb_gro_len(skb),
wsum));
if (sum)
goto flush;
skb->ip_summed = CHECKSUM_UNNECESSARY;
break;
}
return tcp_gro_receive(head, skb);

View File

@ -763,6 +763,8 @@ static struct sk_buff **tcp6_gro_receive(struct sk_buff **head,
struct sk_buff *skb)
{
const struct ipv6hdr *iph = skb_gro_network_header(skb);
__wsum wsum;
__sum16 sum;
switch (skb->ip_summed) {
case CHECKSUM_COMPLETE:
@ -771,11 +773,23 @@ static struct sk_buff **tcp6_gro_receive(struct sk_buff **head,
skb->ip_summed = CHECKSUM_UNNECESSARY;
break;
}
/* fall through */
case CHECKSUM_NONE:
flush:
NAPI_GRO_CB(skb)->flush = 1;
return NULL;
case CHECKSUM_NONE:
wsum = ~csum_unfold(csum_ipv6_magic(&iph->saddr, &iph->daddr,
skb_gro_len(skb),
IPPROTO_TCP, 0));
sum = csum_fold(skb_checksum(skb,
skb_gro_offset(skb),
skb_gro_len(skb),
wsum));
if (sum)
goto flush;
skb->ip_summed = CHECKSUM_UNNECESSARY;
break;
}
return tcp_gro_receive(head, skb);