[UDP]: Introduce UDP encapsulation type for L2TP
This patch adds a new UDP_ENCAP_L2TPINUDP encapsulation type for UDP
sockets. When a UDP socket's encap_type is UDP_ENCAP_L2TPINUDP, the
skb is delivered to a function pointed to by the udp_sock's
encap_rcv funcptr. If the skb isn't wanted by L2TP, it returns >0, which
causes it to be passed through to UDP.
Include padding to put the new encap_rcv field on a 4-byte boundary.
Previously, the only user of UDP encap sockets was ESP, so when
CONFIG_XFRM was not defined, some of the encap code was compiled
out. This patch changes that. As a result, udp_encap_rcv() will
now do a little more work when CONFIG_XFRM is not defined.
Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/udp.h b/include/linux/udp.h
index 6de445c..8ec703f 100644
--- a/include/linux/udp.h
+++ b/include/linux/udp.h
@@ -42,6 +42,7 @@
/* UDP encapsulation types */
#define UDP_ENCAP_ESPINUDP_NON_IKE 1 /* draft-ietf-ipsec-nat-t-ike-00/01 */
#define UDP_ENCAP_ESPINUDP 2 /* draft-ietf-ipsec-udp-encaps-06 */
+#define UDP_ENCAP_L2TPINUDP 3 /* rfc2661 */
#ifdef __KERNEL__
#include <linux/types.h>
@@ -70,6 +71,11 @@
#define UDPLITE_SEND_CC 0x2 /* set via udplite setsockopt */
#define UDPLITE_RECV_CC 0x4 /* set via udplite setsocktopt */
__u8 pcflag; /* marks socket as UDP-Lite if > 0 */
+ __u8 unused[3];
+ /*
+ * For encapsulation sockets.
+ */
+ int (*encap_rcv)(struct sock *sk, struct sk_buff *skb);
};
static inline struct udp_sock *udp_sk(const struct sock *sk)