xauth: add a configuration string option to be passed to XAuth instances

The configuration string is appended to the XAuth backend name, separated by
a colon. The configuration string is passed untouched to the backend, where
it can change the behavior of the XAuth module.

src/libcharon/sa/xauth/xauth_manager.c

@@ -107,6 +107,17 @@ METHOD(xauth_manager_t, create_instance, xauth_method_t*,
 	enumerator_t *enumerator;
 	xauth_entry_t *entry;
 	xauth_method_t *method = NULL;
+	char *profile = NULL;
+
+	if (name)
+	{
+		profile = strchr(name, ':');
+		if (profile)
+		{
+			name = strndup(name, profile - name);
+			profile++;
+		}
+	}
 
 	this->lock->read_lock(this->lock);
 	enumerator = this->methods->create_enumerator(this->methods);
@@ -118,7 +129,7 @@ METHOD(xauth_manager_t, create_instance, xauth_method_t*,
 		}
 		if (role == entry->role && (!name || streq(name, entry->name)))
 		{
-			method = entry->constructor(server, peer);
+			method = entry->constructor(server, peer, profile);
 			if (method)
 			{
 				break;
@@ -127,6 +138,10 @@ METHOD(xauth_manager_t, create_instance, xauth_method_t*,
 	}
 	enumerator->destroy(enumerator);
 	this->lock->unlock(this->lock);
+	if (profile)
+	{
+		free(name);
+	}
 	return method;
 }
 

src/libcharon/sa/xauth/xauth_manager.h

@@ -55,7 +55,11 @@ struct xauth_manager_t {
 	/**
 	 * Create a new XAuth method instance.
 	 *
-	 * @param name			backend name, as it was registered with
+	 * The name may contain an option string, seperated by a colon. This option
+	 * string gets passed to the XAuth constructor to specify the behavior
+	 * of the XAuth method.
+	 *
+	 * @param name			backend name, with optional config string
 	 * @param role			XAUTH_SERVER or XAUTH_PEER
 	 * @param server		identity of the server
 	 * @param peer			identity of the peer (client)

src/libcharon/sa/xauth/xauth_method.h

@@ -104,10 +104,12 @@ struct xauth_method_t {
  *
  * @param server		ID of the server to use for credential lookup
  * @param peer			ID of the peer to use for credential lookup
+ * @param profile		configuration string to pass to XAuth method, or NULL
  * @return				implementation of the eap_method_t interface
  */
 typedef xauth_method_t *(*xauth_constructor_t)(identification_t *server,
-											   identification_t *peer);
+											   identification_t *peer,
+											   char *profile);
 
 /**
  * Helper function to (un-)register XAuth methods from plugin features.