[XFRM]: Restrict upper layer information by bundle.

On MIPv6 usage, XFRM sub policy is enabled.
When main (IPsec) and sub (MIPv6) policy selectors have the same
address set but different upper layer information (i.e. protocol
number and its ports or type/code), multiple bundle should be created.
However, currently we have issue to use the same bundle created for
the first time with all flows covered by the case.

It is useful for the bundle to have the upper layer information
to be restructured correctly if it does not match with the flow.

1. Bundle was created by two policies
Selector from another policy is added to xfrm_dst.
If the flow does not match the selector, it goes to slow path to
restructure new bundle by single policy.

2. Bundle was created by one policy
Flow cache is added to xfrm_dst as originated one. If the flow does
not match the cache, it goes to slow path to try searching another
policy.

Signed-off-by: Masahide NAKAMURA <nakam@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 55 insertions, 0 deletions

diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index dbf9d96a2f0b..263e34e45265 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -1344,6 +1344,40 @@ xfrm_bundle_create(struct xfrm_policy *policy, struct xfrm_state **xfrm, int nx,
 	return err;
 }
 
+static int inline
+xfrm_dst_alloc_copy(void **target, void *src, int size)
+{
+	if (!*target) {
+		*target = kmalloc(size, GFP_ATOMIC);
+		if (!*target)
+			return -ENOMEM;
+	}
+	memcpy(*target, src, size);
+	return 0;
+}
+
+static int inline
+xfrm_dst_update_parent(struct dst_entry *dst, struct xfrm_selector *sel)
+{
+#ifdef CONFIG_XFRM_SUB_POLICY
+	struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
+	return xfrm_dst_alloc_copy((void **)&(xdst->partner),
+				   sel, sizeof(*sel));
+#else
+	return 0;
+#endif
+}
+
+static int inline
+xfrm_dst_update_origin(struct dst_entry *dst, struct flowi *fl)
+{
+#ifdef CONFIG_XFRM_SUB_POLICY
+	struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
+	return xfrm_dst_alloc_copy((void **)&(xdst->origin), fl, sizeof(*fl));
+#else
+	return 0;
+#endif
+}
 
 static int stale_bundle(struct dst_entry *dst);
 
@@ -1532,6 +1566,18 @@ restart:
 			err = -EHOSTUNREACH;
 			goto error;
 		}
+
+		if (npols > 1)
+			err = xfrm_dst_update_parent(dst, &pols[1]->selector);
+		else
+			err = xfrm_dst_update_origin(dst, fl);
+		if (unlikely(err)) {
+			write_unlock_bh(&policy->lock);
+			if (dst)
+				dst_free(dst);
+			goto error;
+		}
+
 		dst->next = policy->bundles;
 		policy->bundles = dst;
 		dst_hold(dst);
@@ -1947,6 +1993,15 @@ int xfrm_bundle_ok(struct xfrm_policy *pol, struct xfrm_dst *first,
 	if (!dst_check(dst->path, ((struct xfrm_dst *)dst)->path_cookie) ||
 	    (dst->dev && !netif_running(dst->dev)))
 		return 0;
+#ifdef CONFIG_XFRM_SUB_POLICY
+	if (fl) {
+		if (first->origin && !flow_cache_uli_match(first->origin, fl))
+			return 0;
+		if (first->partner &&
+		    !xfrm_selector_match(first->partner, fl, family))
+			return 0;
+	}
+#endif
 
 	last = NULL;