[IPSEC]: Rename mode to outer_mode and add inner_mode

This patch adds a new field to xfrm states called inner_mode.  The existing
mode object is renamed to outer_mode.

This is the first part of an attempt to fix inter-family transforms.  As it
is we always use the outer family when determining which mode to use.  As a
result we may end up shoving IPv4 packets into netfilter6 and vice versa.

What we really want is to use the inner family for the first part of outbound
processing and the outer family for the second part.  For inbound processing
we'd use the opposite pairing.

I've also added a check to prevent silly combinations such as transport mode
with inter-family transforms.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/xfrm.h

@@ -186,7 +186,8 @@ struct xfrm_state
 	/* Reference to data common to all the instances of this
 	 * transformer. */
 	struct xfrm_type	*type;
-	struct xfrm_mode	*mode;
+	struct xfrm_mode	*inner_mode;
+	struct xfrm_mode	*outer_mode;
 
 	/* Security context */
 	struct xfrm_sec_ctx	*security;

net/core/pktgen.c

@@ -2454,7 +2454,7 @@ static int pktgen_output_ipsec(struct sk_buff *skb, struct pktgen_dev *pkt_dev)
 	spin_lock(&x->lock);
 	iph = ip_hdr(skb);
 
-	err = x->mode->output(x, skb);
+	err = x->outer_mode->output(x, skb);
 	if (err)
 		goto error;
 	err = x->type->output(x, skb);

net/ipv4/xfrm4_input.c

@@ -91,10 +91,10 @@ int xfrm4_rcv_encap(struct sk_buff *skb, int nexthdr, __be32 spi,
 
 		xfrm_vec[xfrm_nr++] = x;
 
-		if (x->mode->input(x, skb))
+		if (x->outer_mode->input(x, skb))
 			goto drop;
 
-		if (x->mode->flags & XFRM_MODE_FLAG_TUNNEL) {
+		if (x->outer_mode->flags & XFRM_MODE_FLAG_TUNNEL) {
 			decaps = 1;
 			break;
 		}

net/ipv4/xfrm4_output.c

@@ -47,7 +47,7 @@ static inline int xfrm4_output_one(struct sk_buff *skb)
 	struct iphdr *iph;
 	int err;
 
-	if (x->mode->flags & XFRM_MODE_FLAG_TUNNEL) {
+	if (x->outer_mode->flags & XFRM_MODE_FLAG_TUNNEL) {
 		err = xfrm4_tunnel_check_size(skb);
 		if (err)
 			goto error_nolock;

net/ipv4/xfrm4_policy.c

@@ -168,7 +168,7 @@ __xfrm4_bundle_create(struct xfrm_policy *policy, struct xfrm_state **xfrm, int
 		/* Copy neighbout for reachability confirmation */
 		dst_prev->neighbour	= neigh_clone(rt->u.dst.neighbour);
 		dst_prev->input		= rt->u.dst.input;
-		dst_prev->output = dst_prev->xfrm->mode->afinfo->output;
+		dst_prev->output = dst_prev->xfrm->outer_mode->afinfo->output;
 		if (rt0->peer)
 			atomic_inc(&rt0->peer->refcnt);
 		x->u.rt.peer = rt0->peer;

net/ipv6/xfrm6_input.c

@@ -68,10 +68,10 @@ int xfrm6_rcv_spi(struct sk_buff *skb, int nexthdr, __be32 spi)
 
 		xfrm_vec[xfrm_nr++] = x;
 
-		if (x->mode->input(x, skb))
+		if (x->outer_mode->input(x, skb))
 			goto drop;
 
-		if (x->mode->flags & XFRM_MODE_FLAG_TUNNEL) {
+		if (x->outer_mode->flags & XFRM_MODE_FLAG_TUNNEL) {
 			decaps = 1;
 			break;
 		}

net/ipv6/xfrm6_output.c

@@ -50,7 +50,7 @@ static inline int xfrm6_output_one(struct sk_buff *skb)
 	struct ipv6hdr *iph;
 	int err;
 
-	if (x->mode->flags & XFRM_MODE_FLAG_TUNNEL) {
+	if (x->outer_mode->flags & XFRM_MODE_FLAG_TUNNEL) {
 		err = xfrm6_tunnel_check_size(skb);
 		if (err)
 			goto error_nolock;

net/ipv6/xfrm6_policy.c

@@ -230,7 +230,7 @@ __xfrm6_bundle_create(struct xfrm_policy *policy, struct xfrm_state **xfrm, int
 		/* Copy neighbour for reachability confirmation */
 		dst_prev->neighbour	= neigh_clone(rt->u.dst.neighbour);
 		dst_prev->input		= rt->u.dst.input;
-		dst_prev->output = dst_prev->xfrm->mode->afinfo->output;
+		dst_prev->output = dst_prev->xfrm->outer_mode->afinfo->output;
 		/* Sheit... I remember I did this right. Apparently,
 		 * it was magically lost, so this code needs audit */
 		x->u.rt6.rt6i_flags    = rt0->rt6i_flags&(RTCF_BROADCAST|RTCF_MULTICAST|RTCF_LOCAL);

net/xfrm/xfrm_output.c

@@ -63,7 +63,7 @@ int xfrm_output(struct sk_buff *skb)
 				xfrm_replay_notify(x, XFRM_REPLAY_UPDATE);
 		}
 
-		err = x->mode->output(x, skb);
+		err = x->outer_mode->output(x, skb);
 		if (err)
 			goto error;
 
@@ -82,7 +82,7 @@ int xfrm_output(struct sk_buff *skb)
 		}
 		dst = skb->dst;
 		x = dst->xfrm;
-	} while (x && !(x->mode->flags & XFRM_MODE_FLAG_TUNNEL));
+	} while (x && !(x->outer_mode->flags & XFRM_MODE_FLAG_TUNNEL));
 
 	err = 0;
 

net/xfrm/xfrm_policy.c

@@ -1941,7 +1941,7 @@ int xfrm_bundle_ok(struct xfrm_policy *pol, struct xfrm_dst *first,
 			return 0;
 
 		if (strict && fl &&
-		    !(dst->xfrm->mode->flags & XFRM_MODE_FLAG_TUNNEL) &&
+		    !(dst->xfrm->outer_mode->flags & XFRM_MODE_FLAG_TUNNEL) &&
 		    !xfrm_state_addr_flow_check(dst->xfrm, fl, family))
 			return 0;
 

net/xfrm/xfrm_state.c

@@ -377,8 +377,10 @@ static void xfrm_state_gc_destroy(struct xfrm_state *x)
 	kfree(x->calg);
 	kfree(x->encap);
 	kfree(x->coaddr);
-	if (x->mode)
-		xfrm_put_mode(x->mode);
+	if (x->inner_mode)
+		xfrm_put_mode(x->inner_mode);
+	if (x->outer_mode)
+		xfrm_put_mode(x->outer_mode);
 	if (x->type) {
 		x->type->destructor(x);
 		xfrm_put_type(x->type);
@@ -1947,6 +1949,14 @@ int xfrm_init_state(struct xfrm_state *x)
 		goto error;
 
 	err = -EPROTONOSUPPORT;
+	x->inner_mode = xfrm_get_mode(x->props.mode, x->sel.family);
+	if (x->inner_mode == NULL)
+		goto error;
+
+	if (!(x->inner_mode->flags & XFRM_MODE_FLAG_TUNNEL) &&
+	    family != x->sel.family)
+		goto error;
+
 	x->type = xfrm_get_type(x->id.proto, family);
 	if (x->type == NULL)
 		goto error;
@@ -1955,8 +1965,8 @@ int xfrm_init_state(struct xfrm_state *x)
 	if (err)
 		goto error;
 
-	x->mode = xfrm_get_mode(x->props.mode, family);
-	if (x->mode == NULL)
+	x->outer_mode = xfrm_get_mode(x->props.mode, family);
+	if (x->outer_mode == NULL)
 		goto error;
 
 	x->km.state = XFRM_STATE_VALID;