director: After CONNECT was received, make sure we disconnect

The remote side won't be reading anything after the CONNECT, so we have to
disconnect anyway. If we decide that the CONNECT request is wrong, reconnect
after a short delay and hope that the remote agrees with us the next time.

src/director/director-connection.c

@@ -73,6 +73,7 @@
 /* If outgoing director connection exists for less than this many seconds,
    mark the host as failed so we won't try to reconnect to it immediately */
 #define DIRECTOR_SUCCESS_MIN_CONNECT_SECS 40
+#define DIRECTOR_RECONNECT_AFTER_WRONG_CONNECT_MSECS 1000
 #define DIRECTOR_WAIT_DISCONNECT_SECS 10
 #define DIRECTOR_HANDSHAKE_WARN_SECS 29
 #define DIRECTOR_HANDSHAKE_BYTES_LOG_MIN_SECS (60*30)
@@ -1592,6 +1593,31 @@ static bool director_connection_sync(struct director_connection *conn,
 	return TRUE;
 }
 
+static void director_disconnect_timeout(struct director_connection *conn)
+{
+	director_connection_deinit(&conn, "CONNECT requested");
+}
+
+static void
+director_reconnect_after_wrong_connect_timeout(struct director_connection *conn)
+{
+	struct director *dir = conn->dir;
+
+	director_connection_deinit(&conn, "Wrong CONNECT requested");
+	if (dir->right == NULL)
+		director_connect(dir, "Reconnecting after wrong CONNECT request");
+}
+
+static void
+director_reconnect_after_wrong_connect(struct director_connection *conn)
+{
+	if (conn->to_disconnect != NULL)
+		return;
+	conn->to_disconnect =
+		timeout_add_short(DIRECTOR_RECONNECT_AFTER_WRONG_CONNECT_MSECS,
+				  director_reconnect_after_wrong_connect_timeout, conn);
+}
+
 static bool director_cmd_connect(struct director_connection *conn,
 				 const char *const *args)
 {
@@ -1616,6 +1642,7 @@ static bool director_cmd_connect(struct director_connection *conn,
 		/* the old connection is the correct one */
 		dir_debug("Ignoring CONNECT request to %s (current right is %s)",
 			  host->name, dir->right->name);
+		director_reconnect_after_wrong_connect(conn);
 		return TRUE;
 	}
 
@@ -1629,6 +1656,14 @@ static bool director_cmd_connect(struct director_connection *conn,
 	} else {
 		right_state = t_strdup_printf("replacing current right %s",
 					      dir->right->name);
+		/* disconnect from right side immediately - it's not accepting
+		   any further commands from us. */
+		if (conn->dir->right != conn)
+			director_connection_deinit(&conn->dir->right, "CONNECT requested");
+		else if (conn->to_disconnect == NULL) {
+			conn->to_disconnect =
+				timeout_add_short(0, director_disconnect_timeout, conn);
+		}
 	}
 
 	/* connect here */