[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>
diff --git a/net/ipv4/ah4.c b/net/ipv4/ah4.c
index 008e69d..9954297 100644
--- a/net/ipv4/ah4.c
+++ b/net/ipv4/ah4.c
@@ -265,7 +265,7 @@
 		goto error;
 	
 	x->props.header_len = XFRM_ALIGN8(sizeof(struct ip_auth_hdr) + ahp->icv_trunc_len);
-	if (x->props.mode)
+	if (x->props.mode == XFRM_MODE_TUNNEL)
 		x->props.header_len += sizeof(struct iphdr);
 	x->data = ahp;
 
diff --git a/net/ipv4/esp4.c b/net/ipv4/esp4.c
index b428489..e87377e 100644
--- a/net/ipv4/esp4.c
+++ b/net/ipv4/esp4.c
@@ -248,7 +248,7 @@
 		 *    as per draft-ietf-ipsec-udp-encaps-06,
 		 *    section 3.1.2
 		 */
-		if (!x->props.mode)
+		if (x->props.mode == XFRM_MODE_TRANSPORT)
 			skb->ip_summed = CHECKSUM_UNNECESSARY;
 	}
 
@@ -267,7 +267,7 @@
 	struct esp_data *esp = x->data;
 	u32 blksize = ALIGN(crypto_blkcipher_blocksize(esp->conf.tfm), 4);
 
-	if (x->props.mode) {
+	if (x->props.mode == XFRM_MODE_TUNNEL) {
 		mtu = ALIGN(mtu + 2, blksize);
 	} else {
 		/* The worst case. */
@@ -383,7 +383,7 @@
 	if (crypto_blkcipher_setkey(tfm, esp->conf.key, esp->conf.key_len))
 		goto error;
 	x->props.header_len = sizeof(struct ip_esp_hdr) + esp->conf.ivlen;
-	if (x->props.mode)
+	if (x->props.mode == XFRM_MODE_TUNNEL)
 		x->props.header_len += sizeof(struct iphdr);
 	if (x->encap) {
 		struct xfrm_encap_tmpl *encap = x->encap;
diff --git a/net/ipv4/ipcomp.c b/net/ipv4/ipcomp.c
index 5bb9c9f..1734243 100644
--- a/net/ipv4/ipcomp.c
+++ b/net/ipv4/ipcomp.c
@@ -176,7 +176,7 @@
 	return 0;
 
 out_ok:
-	if (x->props.mode)
+	if (x->props.mode == XFRM_MODE_TUNNEL)
 		ip_send_check(iph);
 	return 0;
 }
@@ -216,7 +216,7 @@
 	t->id.daddr.a4 = x->id.daddr.a4;
 	memcpy(&t->sel, &x->sel, sizeof(t->sel));
 	t->props.family = AF_INET;
-	t->props.mode = 1;
+	t->props.mode = XFRM_MODE_TUNNEL;
 	t->props.saddr.a4 = x->props.saddr.a4;
 	t->props.flags = x->props.flags;
 
@@ -416,7 +416,7 @@
 		goto out;
 
 	x->props.header_len = 0;
-	if (x->props.mode)
+	if (x->props.mode == XFRM_MODE_TUNNEL)
 		x->props.header_len += sizeof(struct iphdr);
 
 	mutex_lock(&ipcomp_resource_mutex);
@@ -428,7 +428,7 @@
 		goto error;
 	mutex_unlock(&ipcomp_resource_mutex);
 
-	if (x->props.mode) {
+	if (x->props.mode == XFRM_MODE_TUNNEL) {
 		err = ipcomp_tunnel_attach(x);
 		if (err)
 			goto error_tunnel;
diff --git a/net/ipv4/xfrm4_input.c b/net/ipv4/xfrm4_input.c
index 817ed84..040e847 100644
--- a/net/ipv4/xfrm4_input.c
+++ b/net/ipv4/xfrm4_input.c
@@ -106,7 +106,7 @@
 		if (x->mode->input(x, skb))
 			goto drop;
 
-		if (x->props.mode) {
+		if (x->props.mode == XFRM_MODE_TUNNEL) {
 			decaps = 1;
 			break;
 		}
diff --git a/net/ipv4/xfrm4_output.c b/net/ipv4/xfrm4_output.c
index 4a96a9e..5fd115f 100644
--- a/net/ipv4/xfrm4_output.c
+++ b/net/ipv4/xfrm4_output.c
@@ -54,7 +54,7 @@
 			goto error_nolock;
 	}
 
-	if (x->props.mode) {
+	if (x->props.mode == XFRM_MODE_TUNNEL) {
 		err = xfrm4_tunnel_check_size(skb);
 		if (err)
 			goto error_nolock;
@@ -85,7 +85,7 @@
 		}
 		dst = skb->dst;
 		x = dst->xfrm;
-	} while (x && !x->props.mode);
+	} while (x && (x->props.mode != XFRM_MODE_TUNNEL));
 
 	IPCB(skb)->flags |= IPSKB_XFRM_TRANSFORMED;
 	err = 0;
diff --git a/net/ipv4/xfrm4_policy.c b/net/ipv4/xfrm4_policy.c
index 8f50eae..a5bed74 100644
--- a/net/ipv4/xfrm4_policy.c
+++ b/net/ipv4/xfrm4_policy.c
@@ -96,7 +96,7 @@
 
 		dst1->next = dst_prev;
 		dst_prev = dst1;
-		if (xfrm[i]->props.mode) {
+		if (xfrm[i]->props.mode != XFRM_MODE_TRANSPORT) {
 			remote = xfrm[i]->id.daddr.a4;
 			local  = xfrm[i]->props.saddr.a4;
 			tunnel = 1;
diff --git a/net/ipv4/xfrm4_state.c b/net/ipv4/xfrm4_state.c
index 81e1751..97b0c75 100644
--- a/net/ipv4/xfrm4_state.c
+++ b/net/ipv4/xfrm4_state.c
@@ -42,7 +42,7 @@
 	x->props.saddr = tmpl->saddr;
 	if (x->props.saddr.a4 == 0)
 		x->props.saddr.a4 = saddr->a4;
-	if (tmpl->mode && x->props.saddr.a4 == 0) {
+	if (tmpl->mode == XFRM_MODE_TUNNEL && x->props.saddr.a4 == 0) {
 		struct rtable *rt;
 	        struct flowi fl_tunnel = {
         	        .nl_u = {
diff --git a/net/ipv4/xfrm4_tunnel.c b/net/ipv4/xfrm4_tunnel.c
index f8ceaa1..f110af5 100644
--- a/net/ipv4/xfrm4_tunnel.c
+++ b/net/ipv4/xfrm4_tunnel.c
@@ -28,7 +28,7 @@
 
 static int ipip_init_state(struct xfrm_state *x)
 {
-	if (!x->props.mode)
+	if (x->props.mode != XFRM_MODE_TUNNEL)
 		return -EINVAL;
 
 	if (x->encap)