Changed the order and semantics of rules we expect only once in auth_cfg_t.

These rules are now inserted at the front of the internal list, this
allows to retrieve the rule added last with get(). For other rules the
order in which they are added is maintained (this allows to properly
enumerate them).

src/libstrongswan/credentials/auth_cfg.h

@@ -106,6 +106,9 @@ enum auth_rule_t {
 	AUTH_HELPER_SUBJECT_HASH_URL,
 	/** revocation certificate (CRL, OCSP), certificate_t* */
 	AUTH_HELPER_REVOCATION_CERT,
+
+	/** helper to determine the number of elements in this enum */
+	AUTH_RULE_MAX,
 };
 
 /**
@@ -149,7 +152,14 @@ extern enum_name_t *auth_rule_names;
 struct auth_cfg_t {
 
 	/**
-	 * Add an rule to the set.
+	 * Add a rule to the set.
+	 *
+	 * Rules we expect only once (e.g. identities) implicitly replace previous
+	 * rules of the same type (but pointers to previous values will remain
+	 * valid until the auth_cfg_t object is destroyed).
+	 * Rules that may occur multiple times (e.g. CA certificates) are inserted
+	 * so that they can be enumerated in the order in which they were added.
+	 * For these get() will return the value added first.
 	 *
 	 * @param rule		rule type
 	 * @param ...		associated value to rule
@@ -159,6 +169,8 @@ struct auth_cfg_t {
 	/**
 	 * Get a rule value.
 	 *
+	 * For rules we expect only once the latest value is returned.
+	 *
 	 * @param rule		rule type
 	 * @return			bool if item has been found
 	 */
@@ -167,6 +179,9 @@ struct auth_cfg_t {
 	/**
 	 * Create an enumerator over added rules.
 	 *
+	 * Refer to add() regarding the order in which rules are enumerated.
+	 * For rules we expect only once the latest value is enumerated only.
+	 *
 	 * @return			enumerator over (auth_rule_t, union{void*,uintpr_t})
 	 */
 	enumerator_t* (*create_enumerator)(auth_cfg_t *this);
@@ -217,6 +232,8 @@ struct auth_cfg_t {
 	/**
 	 * Check two configs for equality.
 	 *
+	 * For rules we expect only once the latest value is compared only.
+	 *
 	 * @param other		other config to compare against this
 	 * @return			TRUE if auth infos identical
 	 */