[PATCH 3.12 48/83] gro: Clean up tcpX_gro_receive checksum verification

Greg Kroah-Hartman
2013-12-06T22:32:40Z

From: Herbert Xu <herbert@gondor.apana.org.au>

[ Upstream commit b8ee93ba80b5a0b6c3c06b65c34dd1276f16c047 ]

This patch simplifies the checksum verification in tcpX_gro_receive
by reusing the CHECKSUM_COMPLETE code for CHECKSUM_NONE. All it
does for CHECKSUM_NONE is compute the partial checksum and then
treat it as if it came from the hardware (CHECKSUM_COMPLETE).

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Cheers,
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/ipv4/tcp_offload.c | 26 ++++++++++----------------
net/ipv6/tcpv6_offload.c | 27 ++++++++++-----------------
2 files changed, 20 insertions(+), 33 deletions(-)

--- a/net/ipv4/tcp_offload.c
+++ b/net/ipv4/tcp_offload.c
@@ -272,35 +272,29 @@ static struct sk_buff **tcp4_gro_receive
{
const struct iphdr *iph = skb_gro_network_header(skb);
__wsum wsum;
- __sum16 sum;

/* Don't bother verifying checksum if we're going to flush anyway. */
if (NAPI_GRO_CB(skb)->flush)
goto skip_csum;

+ wsum = skb->csum;
+
switch (skb->ip_summed) {
+ case CHECKSUM_NONE:
+ wsum = skb_checksum(skb, skb_gro_offset(skb), skb_gro_len(skb),
+ 0);
+
+ /* fall through */
+
case CHECKSUM_COMPLETE:
if (!tcp_v4_check(skb_gro_len(skb), iph->saddr, iph->daddr,
- skb->csum)) {
+ wsum)) {
skb->ip_summed = CHECKSUM_UNNECESSARY;
break;
}
-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;
}

skip_csum:
--- a/net/ipv6/tcpv6_offload.c
+++ b/net/ipv6/tcpv6_offload.c
@@ -37,36 +37,29 @@ static struct sk_buff **tcp6_gro_receive
{
const struct ipv6hdr *iph = skb_gro_network_header(skb);
__wsum wsum;
- __sum16 sum;

/* Don't bother verifying checksum if we're going to flush anyway. */
if (NAPI_GRO_CB(skb)->flush)
goto skip_csum;

+ wsum = skb->csum;
+
switch (skb->ip_summed) {
+ case CHECKSUM_NONE:
+ wsum = skb_checksum(skb, skb_gro_offset(skb), skb_gro_len(skb),
+ wsum);
+
+ /* fall through */
+
case CHECKSUM_COMPLETE:
if (!tcp_v6_check(skb_gro_len(skb), &iph->saddr, &iph->daddr,
- skb->csum)) {
+ wsum)) {
skb->ip_summed = CHECKSUM_UNNECESSARY;
break;
}
-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;
}