netdev - [net PATCH] net: Reset encap_level to avoid resetting features on inner IP headers

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Date:	Tue, 22 Mar 2016 16:18:07 -0700
From:	Alexander Duyck <aduyck@...antis.com>
To:	tom@...bertland.com, kernel-team@...com, davem@...emloft.net,
	alexander.duyck@...il.com, netdev@...r.kernel.org
Subject: [net PATCH] net: Reset encap_level to avoid resetting features on
 inner IP headers

This patch corrects an oversight in which we were allowing the encap_level
value to pass from the outer headers to the inner headers.  As a result we
were incorrectly identifying UDP or GRE tunnels as also making use of ipip
or sit when the second header actually represented a tunnel encapsulated in
either a UDP or GRE tunnel which already had the features masked.

Fixes: 76443456227097179c1482 ("net: Move GSO csum into SKB_GSO_CB")
Reported-by: Tom Herbert <tom@...bertland.com>
Signed-off-by: Alexander Duyck <aduyck@...antis.com>
---
 net/ipv4/gre_offload.c |    1 +
 net/ipv4/udp_offload.c |    1 +
 2 files changed, 2 insertions(+)

diff --git a/net/ipv4/gre_offload.c b/net/ipv4/gre_offload.c
index dea0390d65bb..43a5c76742dc 100644
--- a/net/ipv4/gre_offload.c
+++ b/net/ipv4/gre_offload.c
@@ -49,6 +49,7 @@ static struct sk_buff *gre_gso_segment(struct sk_buff *skb,
 
 	/* setup inner skb. */
 	skb->encapsulation = 0;
+	SKB_GSO_CB(skb)->encap_level = 0;
 	__skb_pull(skb, tnl_hlen);
 	skb_reset_mac_header(skb);
 	skb_set_network_header(skb, skb_inner_network_offset(skb));
diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c
index 5fcb93269afb..80236a9e1769 100644
--- a/net/ipv4/udp_offload.c
+++ b/net/ipv4/udp_offload.c
@@ -56,6 +56,7 @@ static struct sk_buff *__skb_udp_tunnel_segment(struct sk_buff *skb,
 
 	/* setup inner skb. */
 	skb->encapsulation = 0;
+	SKB_GSO_CB(skb)->encap_level = 0;
 	__skb_pull(skb, tnl_hlen);
 	skb_reset_mac_header(skb);
 	skb_set_network_header(skb, skb_inner_network_offset(skb));