netlabel: Add network address selectors to the NetLabel/LSM domain mapping

This patch extends the NetLabel traffic labeling capabilities to individual
packets based not only on the LSM domain but the by the destination address
as well.  The changes here only affect the core NetLabel infrastructre,
changes to the NetLabel KAPI and individial protocol engines are also
required but are split out into a different patch to ease review.

Signed-off-by: Paul Moore <paul.moore@hp.com>
Reviewed-by: James Morris <jmorris@namei.org>
diff --git a/net/netlabel/netlabel_kapi.c b/net/netlabel/netlabel_kapi.c
index 7d8ecea..8b820dc 100644
--- a/net/netlabel/netlabel_kapi.c
+++ b/net/netlabel/netlabel_kapi.c
@@ -419,7 +419,9 @@
  * Attach the correct label to the given socket using the security attributes
  * specified in @secattr.  This function requires exclusive access to @sk,
  * which means it either needs to be in the process of being created or locked.
- * Returns zero on success, negative values on failure.
+ * Returns zero on success, -EDESTADDRREQ if the domain is configured to use
+ * network address selectors (can't blindly label the socket), and negative
+ * values on all other failures.
  *
  */
 int netlbl_sock_setattr(struct sock *sk,
@@ -433,6 +435,9 @@
 	if (dom_entry == NULL)
 		goto socket_setattr_return;
 	switch (dom_entry->type) {
+	case NETLBL_NLTYPE_ADDRSELECT:
+		ret_val = -EDESTADDRREQ;
+		break;
 	case NETLBL_NLTYPE_CIPSOV4:
 		ret_val = cipso_v4_sock_setattr(sk,
 						dom_entry->type_def.cipsov4,