tunneling: Add generic Tunnel segmentation.

Adds generic tunneling offloading support for IPv4-UDP based
tunnels.
GSO type is added to request this offload for a skb.
netdev feature NETIF_F_UDP_TUNNEL is added for hardware offloaded
udp-tunnel support. Currently no device supports this feature,
software offload is used.

This can be used by tunneling protocols like VXLAN.

CC: Jesse Gross <jesse@nicira.com>
Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Acked-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 8 insertions, 1 deletions

diff --git a/net/ipv6/ip6_offload.c b/net/ipv6/ip6_offload.c
index 7a0d25a5479c..71b766ee821d 100644
--- a/net/ipv6/ip6_offload.c
+++ b/net/ipv6/ip6_offload.c
@@ -97,6 +97,7 @@ static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb,
                        SKB_GSO_DODGY |
                        SKB_GSO_TCP_ECN |
                        SKB_GSO_GRE |
+                       SKB_GSO_UDP_TUNNEL |
                        SKB_GSO_TCPV6 |
                        0)))
                 goto out;
diff --git a/net/ipv6/udp_offload.c b/net/ipv6/udp_offload.c
index cf05cf073c51..3bb3a891a424 100644
--- a/net/ipv6/udp_offload.c
+++ b/net/ipv6/udp_offload.c
@@ -21,6 +21,10 @@ static int udp6_ufo_send_check(struct sk_buff *skb)
         const struct ipv6hdr *ipv6h;
         struct udphdr *uh;
 
+        /* UDP Tunnel offload on ipv6 is not yet supported. */
+        if (skb->encapsulation)
+                return -EINVAL;
+
         if (!pskb_may_pull(skb, sizeof(*uh)))
                 return -EINVAL;
 
@@ -56,7 +60,9 @@ static struct sk_buff *udp6_ufo_fragment(struct sk_buff *skb,
                 /* Packet is from an untrusted source, reset gso_segs. */
                 int type = skb_shinfo(skb)->gso_type;
 
-                if (unlikely(type & ~(SKB_GSO_UDP | SKB_GSO_DODGY |
+                if (unlikely(type & ~(SKB_GSO_UDP |
+                                      SKB_GSO_DODGY |
+                                      SKB_GSO_UDP_TUNNEL |
                                       SKB_GSO_GRE) ||
                              !(type & (SKB_GSO_UDP))))
                         goto out;