udp: Add udp_sock_create for UDP tunnels to open listener socket

Added udp_tunnel.c which can contain some common functions for UDP
tunnels. The first function in this is udp_sock_create which is used
to open the listener port for a UDP tunnel.

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/net/ipv4/Kconfig b/net/ipv4/Kconfig
index 05c57f0fcabe..dbc10d84161f 100644
--- a/net/ipv4/Kconfig
+++ b/net/ipv4/Kconfig
@@ -307,6 +307,10 @@ config NET_IPVTI
           the notion of a secure tunnel for IPSEC and then use routing protocol
           on top.
 
+config NET_UDP_TUNNEL
+        tristate
+        default n
+
 config INET_AH
         tristate "IP: AH transformation"
         select XFRM_ALGO