[Trusty SRU][PATCH] net-gre-gro: Fix a bug that breaks the forwarding path

[Chris J Arges]

From: Jerry Chu <hkchu at google.com>

Fixed a bug that was introduced by my GRE-GRO patch
(bf5a755f5e9186406bbf50f4087100af5bd68e40 net-gre-gro: Add GRE
support to the GRO stack) that breaks the forwarding path
because various GSO related fields were not set. The bug will
cause on the egress path either the GSO code to fail, or a
GRE-TSO capable (NETIF_F_GSO_GRE) NICs to choke. The following
fix has been tested for both cases.

Signed-off-by: H.K. Jerry Chu <hkchu at google.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
(cherry picked from commit c3caf1192f904de2f1381211f564537235d50de3)
Signed-off-by: Chris J Arges <chris.j.arges at canonical.com>
---
 net/core/dev.c           | 2 ++
 net/ipv4/af_inet.c       | 3 +++
 net/ipv4/gre_offload.c   | 3 +++
 net/ipv4/tcp_offload.c   | 2 +-
 net/ipv6/tcpv6_offload.c | 2 +-
 5 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index 4e4c71d..072aa61 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4031,6 +4031,8 @@ static void napi_reuse_skb(struct napi_struct *napi, struct sk_buff *skb)
 	skb->vlan_tci = 0;
 	skb->dev = napi->dev;
 	skb->skb_iif = 0;
+	skb->encapsulation = 0;
+	skb_shinfo(skb)->gso_type = 0;
 	skb->truesize = SKB_TRUESIZE(skb_end_offset(skb));
 
 	napi->skb = skb;
diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index bcf1b5d..d73a50f 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -1437,6 +1437,9 @@ static int inet_gro_complete(struct sk_buff *skb, int nhoff)
 	int proto = iph->protocol;
 	int err = -ENOSYS;
 
+	if (skb->encapsulation)
+		skb_set_inner_network_header(skb, nhoff);
+
 	csum_replace2(&iph->check, iph->tot_len, newlen);
 	iph->tot_len = newlen;
 
diff --git a/net/ipv4/gre_offload.c b/net/ipv4/gre_offload.c
index 746a7b1..cecc87e 100644
--- a/net/ipv4/gre_offload.c
+++ b/net/ipv4/gre_offload.c
@@ -258,6 +258,9 @@ int gre_gro_complete(struct sk_buff *skb, int nhoff)
 	int err = -ENOENT;
 	__be16 type;
 
+	skb->encapsulation = 1;
+	skb_shinfo(skb)->gso_type = SKB_GSO_GRE;
+
 	type = greh->protocol;
 	if (greh->flags & GRE_KEY)
 		grehlen += GRE_HEADER_SECTION;
diff --git a/net/ipv4/tcp_offload.c b/net/ipv4/tcp_offload.c
index 771a395..6633826 100644
--- a/net/ipv4/tcp_offload.c
+++ b/net/ipv4/tcp_offload.c
@@ -312,7 +312,7 @@ static int tcp4_gro_complete(struct sk_buff *skb, int thoff)
 
 	th->check = ~tcp_v4_check(skb->len - thoff, iph->saddr,
 				  iph->daddr, 0);
-	skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
+	skb_shinfo(skb)->gso_type |= SKB_GSO_TCPV4;
 
 	return tcp_gro_complete(skb);
 }
diff --git a/net/ipv6/tcpv6_offload.c b/net/ipv6/tcpv6_offload.c
index 0d78132..3e8458a 100644
--- a/net/ipv6/tcpv6_offload.c
+++ b/net/ipv6/tcpv6_offload.c
@@ -73,7 +73,7 @@ static int tcp6_gro_complete(struct sk_buff *skb, int thoff)
 
 	th->check = ~tcp_v6_check(skb->len - thoff, &iph->saddr,
 				  &iph->daddr, 0);
-	skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
+	skb_shinfo(skb)->gso_type |= SKB_GSO_TCPV6;
 
 	return tcp_gro_complete(skb);
 }
-- 
1.9.1