[XFRM]: Introduce a helper to compare id protocol.

Put the helper to header for future use.
Based on MIPL2 kernel patch.
Signed-off-by: Masahide NAKAMURA <nakam@linux-ipv6.org>
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/xfrm.h

@@ -9,6 +9,7 @@
 #include <linux/skbuff.h>
 #include <linux/socket.h>
 #include <linux/pfkeyv2.h>
+#include <linux/ipsec.h>
 #include <linux/in6.h>
 #include <linux/mutex.h>
 
@@ -835,6 +836,11 @@ static inline int xfrm_state_kern(struct xfrm_state *x)
 	return atomic_read(&x->tunnel_users);
 }
 
+static inline int xfrm_id_proto_match(u8 proto, u8 userproto)
+{
+	return (userproto == IPSEC_PROTO_ANY || proto == userproto);
+}
+
 /*
  * xfrm algorithm information
  */

net/xfrm/xfrm_state.c

@@ -294,7 +294,7 @@ void xfrm_state_flush(u8 proto)
 restart:
 		list_for_each_entry(x, xfrm_state_bydst+i, bydst) {
 			if (!xfrm_state_kern(x) &&
-			    (proto == IPSEC_PROTO_ANY || x->id.proto == proto)) {
+			    xfrm_id_proto_match(x->id.proto, proto)) {
 				xfrm_state_hold(x);
 				spin_unlock_bh(&xfrm_state_lock);
 
@@ -772,7 +772,7 @@ int xfrm_state_walk(u8 proto, int (*func)(struct xfrm_state *, int, void*),
 	spin_lock_bh(&xfrm_state_lock);
 	for (i = 0; i < XFRM_DST_HSIZE; i++) {
 		list_for_each_entry(x, xfrm_state_bydst+i, bydst) {
-			if (proto == IPSEC_PROTO_ANY || x->id.proto == proto)
+			if (xfrm_id_proto_match(x->id.proto, proto))
 				count++;
 		}
 	}
@@ -783,7 +783,7 @@ int xfrm_state_walk(u8 proto, int (*func)(struct xfrm_state *, int, void*),
 
 	for (i = 0; i < XFRM_DST_HSIZE; i++) {
 		list_for_each_entry(x, xfrm_state_bydst+i, bydst) {
-			if (proto != IPSEC_PROTO_ANY && x->id.proto != proto)
+			if (!xfrm_id_proto_match(x->id.proto, proto))
 				continue;
 			err = func(x, --count, data);
 			if (err)