diff --git a/healthcheck/tor_connection.go b/healthcheck/tor_connection.go new file mode 100644 index 000000000..13f90a8c8 --- /dev/null +++ b/healthcheck/tor_connection.go @@ -0,0 +1,86 @@ +package healthcheck + +import ( + "errors" + "fmt" + "io" + "syscall" + + "github.com/lightningnetwork/lnd/tor" +) + +// CheckTorServiceStatus checks whether the onion service is reachable by +// sending a GETINFO command to the Tor daemon using our tor controller. +// We will get an EOF or a broken pipe error if the Tor daemon is +// stopped/restarted as the previously created socket connection is no longer +// open. In this case, we will attempt a restart on our tor controller. If the +// tor daemon comes back, a new socket connection will then be created. +func CheckTorServiceStatus(tc *tor.Controller, + createService func() error) error { + + // Send a cmd using GETINFO onions/current and checks that our known + // onion serviceID can be found. + err := tc.CheckOnionService() + if err == nil { + return nil + } + + log.Debugf("Checking tor service got: %v", err) + + switch { + // We will get an EOF if the connection is lost. In this case, we will + // return an error and wait for the Tor daemon to come back. We won't + // attempt to make a new connection since we know Tor daemon is down. + case errors.Is(err, io.EOF), errors.Is(err, syscall.ECONNREFUSED): + return fmt.Errorf("Tor daemon connection lost, " + + "check if Tor is up and running") + + // Once Tor daemon is down, we will get a broken pipe error when we use + // the existing connection to make a GETINFO request since that socket + // has now been closed. As Tor daemon might not be running yet, we will + // attempt to make a new connection till Tor daemon is back. + case errors.Is(err, syscall.EPIPE): + log.Warnf("Tor connection lost, attempting a tor controller " + + "re-connection...") + + // If the restart fails, we will attempt again during our next + // healthcheck cycle. + return restartTorController(tc, createService) + + // If this is not a connection layer error, such as + // ErrServiceNotCreated or ErrServiceIDUnmatch, there's little we can + // do but to report the error to the user. + default: + return err + } +} + +// restartTorController attempts to make a new connection to the Tor daemon and +// re-create the Hidden Service. +func restartTorController(tc *tor.Controller, + createService func() error) error { + + err := tc.Reconnect() + + // If we get a connection refused error, it means Tor daemon might not + // be started. + if errors.Is(err, syscall.ECONNREFUSED) { + return fmt.Errorf("check if Tor daemon is running") + } + + // Otherwise, we get an unexpected and return it. + if err != nil { + log.Errorf("Re-connectting tor got err: %v", err) + return err + } + + // Recreate the Hidden Service. + if err := createService(); err != nil { + log.Errorf("Re-create service tor got err: %v", err) + return err + } + + log.Info("Successfully restarted tor connection!") + + return nil +}