[PATCH 3.16 273/306] ipv6: Set skb->protocol properly for local output

From: Ben Hutchings
Date: Wed Feb 15 2017 - 19:18:41 EST

3.16.40-rc1 review patch. If anyone has any objections, please let me know.


From: Eli Cooper <elicooper@xxxxxxx>

commit b4e479a96fc398ccf83bb1cffb4ffef8631beaf1 upstream.

When xfrm is applied to TSO/GSO packets, it follows this path:

xfrm_output() -> xfrm_output_gso() -> skb_gso_segment()

where skb_gso_segment() relies on skb->protocol to function properly.

This patch sets skb->protocol to ETH_P_IPV6 before dst_output() is called,
fixing a bug where GSO packets sent through an ipip6 tunnel are dropped
when xfrm is involved.

Signed-off-by: Eli Cooper <elicooper@xxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
net/ipv6/output_core.c | 2 ++
1 file changed, 2 insertions(+)

--- a/net/ipv6/output_core.c
+++ b/net/ipv6/output_core.c
@@ -114,6 +114,8 @@ int __ip6_local_out(struct sk_buff *skb)
ipv6_hdr(skb)->payload_len = htons(len);
IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr);

+ skb->protocol = htons(ETH_P_IPV6);
return nf_hook(NFPROTO_IPV6, NF_INET_LOCAL_OUT, skb, NULL,
skb_dst(skb)->dev, dst_output);