gre: Setup and TX path for gre/UDP foo-over-udp encapsulation

Added netlink attrs to configure FOU encapsulation for GRE, netlink
handling of these flags, and properly adjust MTU for encapsulation.
ip_tunnel_encap is called from ip_tunnel_xmit to actually perform FOU
encapsulation.

Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 4 insertions, 0 deletions

diff --git a/include/uapi/linux/if_tunnel.h b/include/uapi/linux/if_tunnel.h
index 9fedca7d8dae..7c832afdfa94 100644
--- a/include/uapi/linux/if_tunnel.h
+++ b/include/uapi/linux/if_tunnel.h
@@ -106,6 +106,10 @@ enum {
         IFLA_GRE_ENCAP_LIMIT,
         IFLA_GRE_FLOWINFO,
         IFLA_GRE_FLAGS,
+        IFLA_GRE_ENCAP_TYPE,
+        IFLA_GRE_ENCAP_FLAGS,
+        IFLA_GRE_ENCAP_SPORT,
+        IFLA_GRE_ENCAP_DPORT,
         __IFLA_GRE_MAX,
 };