[PATCH 3.14 138/140] ipv6: gro: fix CHECKSUM_COMPLETE support

Greg Kroah-Hartman
2014-05-29T04:37:51Z

From: Eric Dumazet <edumazet@google.com>

[ Upstream commit 4de462ab63e23953fd05da511aeb460ae10cc726 ]

When GRE support was added in linux-3.14, CHECKSUM_COMPLETE handling
broke on GRE+IPv6 because we did not update/use the appropriate csum :

GRO layer is supposed to use/update NAPI_GRO_CB(skb)->csum instead of
skb->csum

Tested using a GRE tunnel and IPv6 traffic. GRO aggregation now happens
at the first level (ethernet device) instead of being done in gre
tunnel. Native IPv6+TCP is still properly aggregated.

Fixes: bf5a755f5e918 ("net-gre-gro: Add GRE support to the GRO stack")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Jerry Chu <hkchu@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/ipv6/ip6_offload.c | 6 +-----
net/ipv6/tcpv6_offload.c | 2 +-
2 files changed, 2 insertions(+), 6 deletions(-)

--- a/net/ipv6/ip6_offload.c
+++ b/net/ipv6/ip6_offload.c
@@ -196,7 +196,6 @@ static struct sk_buff **ipv6_gro_receive
unsigned int off;
u16 flush = 1;
int proto;
- __wsum csum;

off = skb_gro_offset(skb);
hlen = off + sizeof(*iph);
@@ -264,13 +263,10 @@ static struct sk_buff **ipv6_gro_receive

NAPI_GRO_CB(skb)->flush |= flush;

- csum = skb->csum;
- skb_postpull_rcsum(skb, iph, skb_network_header_len(skb));
+ skb_gro_postpull_rcsum(skb, iph, nlen);

pp = ops->callbacks.gro_receive(head, skb);

- skb->csum = csum;
-
out_unlock:
rcu_read_unlock();

--- a/net/ipv6/tcpv6_offload.c
+++ b/net/ipv6/tcpv6_offload.c
@@ -42,7 +42,7 @@ static struct sk_buff **tcp6_gro_receive
if (NAPI_GRO_CB(skb)->flush)
goto skip_csum;

- wsum = skb->csum;
+ wsum = NAPI_GRO_CB(skb)->csum;

switch (skb->ip_summed) {