[XFRM]: Add XFRM_MODE_xxx for future use.

Transformation mode is used as either IPsec transport or tunnel.
It is required to add two more items, route optimization and inbound trigger
for Mobile IPv6.
Based on MIPL2 kernel patch.

This patch was also written by: Ville Nuorvala <vnuorval@tcs.hut.fi>

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>

net/key/af_key.c

@@ -1765,7 +1765,7 @@ parse_ipsecrequest(struct xfrm_policy *xp, struct sadb_x_ipsecrequest *rq)
 	}
 
 	/* addresses present only in tunnel mode */
-	if (t->mode) {
+	if (t->mode == XFRM_MODE_TUNNEL) {
 		switch (xp->family) {
 		case AF_INET:
 			sin = (void*)(rq+1);
@@ -1997,7 +1997,7 @@ static void pfkey_xfrm_policy2msg(struct sk_buff *skb, struct xfrm_policy *xp, i
 		int req_size;
 
 		req_size = sizeof(struct sadb_x_ipsecrequest);
-		if (t->mode)
+		if (t->mode == XFRM_MODE_TUNNEL)
 			req_size += 2*socklen;
 		else
 			size -= 2*socklen;
@@ -2013,7 +2013,7 @@ static void pfkey_xfrm_policy2msg(struct sk_buff *skb, struct xfrm_policy *xp, i
 		if (t->optional)
 			rq->sadb_x_ipsecrequest_level = IPSEC_LEVEL_USE;
 		rq->sadb_x_ipsecrequest_reqid = t->reqid;
-		if (t->mode) {
+		if (t->mode == XFRM_MODE_TUNNEL) {
 			switch (xp->family) {
 			case AF_INET:
 				sin = (void*)(rq+1);