package supervisor import ( "context" "errors" "fmt" "net" "strings" "time" "github.com/google/uuid" "github.com/lucas-clemente/quic-go" "github.com/rs/zerolog" "github.com/cloudflare/cloudflared/connection" "github.com/cloudflare/cloudflared/edgediscovery" "github.com/cloudflare/cloudflared/orchestration" "github.com/cloudflare/cloudflared/retry" "github.com/cloudflare/cloudflared/signal" "github.com/cloudflare/cloudflared/tunnelstate" ) const ( // SRV and TXT record resolution TTL ResolveTTL = time.Hour // Waiting time before retrying a failed tunnel connection tunnelRetryDuration = time.Second * 10 // Interval between registering new tunnels registrationInterval = time.Second subsystemRefreshAuth = "refresh_auth" // Maximum exponent for 'Authenticate' exponential backoff refreshAuthMaxBackoff = 10 // Waiting time before retrying a failed 'Authenticate' connection refreshAuthRetryDuration = time.Second * 10 ) // Supervisor manages non-declarative tunnels. Establishes TCP connections with the edge, and // reconnects them if they disconnect. type Supervisor struct { cloudflaredUUID uuid.UUID config *TunnelConfig orchestrator *orchestration.Orchestrator edgeIPs *edgediscovery.Edge edgeTunnelServer TunnelServer tunnelErrors chan tunnelError tunnelsConnecting map[int]chan struct{} tunnelsProtocolFallback map[int]*protocolFallback // nextConnectedIndex and nextConnectedSignal are used to wait for all // currently-connecting tunnels to finish connecting so we can reset backoff timer nextConnectedIndex int nextConnectedSignal chan struct{} log *ConnAwareLogger logTransport *zerolog.Logger reconnectCredentialManager *reconnectCredentialManager reconnectCh chan ReconnectSignal gracefulShutdownC <-chan struct{} } var errEarlyShutdown = errors.New("shutdown started") type tunnelError struct { index int err error } func NewSupervisor(config *TunnelConfig, orchestrator *orchestration.Orchestrator, reconnectCh chan ReconnectSignal, gracefulShutdownC <-chan struct{}) (*Supervisor, error) { cloudflaredUUID, err := uuid.NewRandom() if err != nil { return nil, fmt.Errorf("failed to generate cloudflared instance ID: %w", err) } isStaticEdge := len(config.EdgeAddrs) > 0 var edgeIPs *edgediscovery.Edge if isStaticEdge { // static edge addresses edgeIPs, err = edgediscovery.StaticEdge(config.Log, config.EdgeAddrs) } else { edgeIPs, err = edgediscovery.ResolveEdge(config.Log, config.Region, config.EdgeIPVersion) } if err != nil { return nil, err } reconnectCredentialManager := newReconnectCredentialManager(connection.MetricsNamespace, connection.TunnelSubsystem, config.HAConnections) tracker := tunnelstate.NewConnTracker(config.Log) log := NewConnAwareLogger(config.Log, tracker, config.Observer) edgeAddrHandler := NewIPAddrFallback(config.MaxEdgeAddrRetries) edgeTunnelServer := EdgeTunnelServer{ config: config, cloudflaredUUID: cloudflaredUUID, orchestrator: orchestrator, credentialManager: reconnectCredentialManager, edgeAddrs: edgeIPs, edgeAddrHandler: edgeAddrHandler, tracker: tracker, reconnectCh: reconnectCh, gracefulShutdownC: gracefulShutdownC, connAwareLogger: log, } return &Supervisor{ cloudflaredUUID: cloudflaredUUID, config: config, orchestrator: orchestrator, edgeIPs: edgeIPs, edgeTunnelServer: &edgeTunnelServer, tunnelErrors: make(chan tunnelError), tunnelsConnecting: map[int]chan struct{}{}, tunnelsProtocolFallback: map[int]*protocolFallback{}, log: log, logTransport: config.LogTransport, reconnectCredentialManager: reconnectCredentialManager, reconnectCh: reconnectCh, gracefulShutdownC: gracefulShutdownC, }, nil } func (s *Supervisor) Run( ctx context.Context, connectedSignal *signal.Signal, ) error { if s.config.PacketConfig != nil { go func() { if err := s.config.PacketConfig.ICMPRouter.Serve(ctx); err != nil { if errors.Is(err, net.ErrClosed) { s.log.Logger().Info().Err(err).Msg("icmp router terminated") } else { s.log.Logger().Err(err).Msg("icmp router terminated") } } }() } if err := s.initialize(ctx, connectedSignal); err != nil { if err == errEarlyShutdown { return nil } return err } var tunnelsWaiting []int tunnelsActive := s.config.HAConnections backoff := retry.BackoffHandler{MaxRetries: s.config.Retries, BaseTime: tunnelRetryDuration, RetryForever: true} var backoffTimer <-chan time.Time shuttingDown := false for { select { // Context cancelled case <-ctx.Done(): for tunnelsActive > 0 { <-s.tunnelErrors tunnelsActive-- } return nil // startTunnel completed with a response // (note that this may also be caused by context cancellation) case tunnelError := <-s.tunnelErrors: tunnelsActive-- if tunnelError.err != nil && !shuttingDown { switch tunnelError.err.(type) { case ReconnectSignal: // For tunnels that closed with reconnect signal, we reconnect immediately go s.startTunnel(ctx, tunnelError.index, s.newConnectedTunnelSignal(tunnelError.index)) tunnelsActive++ continue } // Make sure we don't continue if there is no more fallback allowed if _, retry := s.tunnelsProtocolFallback[tunnelError.index].GetMaxBackoffDuration(ctx); !retry { continue } s.log.ConnAwareLogger().Err(tunnelError.err).Int(connection.LogFieldConnIndex, tunnelError.index).Msg("Connection terminated") tunnelsWaiting = append(tunnelsWaiting, tunnelError.index) s.waitForNextTunnel(tunnelError.index) if backoffTimer == nil { backoffTimer = backoff.BackoffTimer() } } else if tunnelsActive == 0 { s.log.ConnAwareLogger().Msg("no more connections active and exiting") // All connected tunnels exited gracefully, no more work to do return nil } // Backoff was set and its timer expired case <-backoffTimer: backoffTimer = nil for _, index := range tunnelsWaiting { go s.startTunnel(ctx, index, s.newConnectedTunnelSignal(index)) } tunnelsActive += len(tunnelsWaiting) tunnelsWaiting = nil // Tunnel successfully connected case <-s.nextConnectedSignal: if !s.waitForNextTunnel(s.nextConnectedIndex) && len(tunnelsWaiting) == 0 { // No more tunnels outstanding, clear backoff timer backoff.SetGracePeriod() } case <-s.gracefulShutdownC: shuttingDown = true } } } // Returns nil if initialization succeeded, else the initialization error. // Attempts here will be made to connect one tunnel, if successful, it will // connect the available tunnels up to config.HAConnections. func (s *Supervisor) initialize( ctx context.Context, connectedSignal *signal.Signal, ) error { availableAddrs := s.edgeIPs.AvailableAddrs() if s.config.HAConnections > availableAddrs { s.log.Logger().Info().Msgf("You requested %d HA connections but I can give you at most %d.", s.config.HAConnections, availableAddrs) s.config.HAConnections = availableAddrs } s.tunnelsProtocolFallback[0] = &protocolFallback{ retry.BackoffHandler{MaxRetries: s.config.Retries, RetryForever: true}, s.config.ProtocolSelector.Current(), false, } go s.startFirstTunnel(ctx, connectedSignal) // Wait for response from first tunnel before proceeding to attempt other HA edge tunnels select { case <-ctx.Done(): <-s.tunnelErrors return ctx.Err() case tunnelError := <-s.tunnelErrors: return tunnelError.err case <-s.gracefulShutdownC: return errEarlyShutdown case <-connectedSignal.Wait(): } // At least one successful connection, so start the rest for i := 1; i < s.config.HAConnections; i++ { s.tunnelsProtocolFallback[i] = &protocolFallback{ retry.BackoffHandler{MaxRetries: s.config.Retries, RetryForever: true}, // Set the protocol we know the first tunnel connected with. s.tunnelsProtocolFallback[0].protocol, false, } go s.startTunnel(ctx, i, s.newConnectedTunnelSignal(i)) time.Sleep(registrationInterval) } return nil } // startTunnel starts the first tunnel connection. The resulting error will be sent on // s.tunnelErrors. It will send a signal via connectedSignal if registration succeed func (s *Supervisor) startFirstTunnel( ctx context.Context, connectedSignal *signal.Signal, ) { var ( err error ) const firstConnIndex = 0 isStaticEdge := len(s.config.EdgeAddrs) > 0 defer func() { s.tunnelErrors <- tunnelError{index: firstConnIndex, err: err} }() // If the first tunnel disconnects, keep restarting it. for { err = s.edgeTunnelServer.Serve(ctx, firstConnIndex, s.tunnelsProtocolFallback[firstConnIndex], connectedSignal) if ctx.Err() != nil { return } if err == nil { return } // Make sure we don't continue if there is no more fallback allowed if _, retry := s.tunnelsProtocolFallback[firstConnIndex].GetMaxBackoffDuration(ctx); !retry { return } // Try again for Unauthorized errors because we hope them to be // transient due to edge propagation lag on new Tunnels. if strings.Contains(err.Error(), "Unauthorized") { continue } switch err.(type) { case edgediscovery.ErrNoAddressesLeft: // If your provided addresses are not available, we will keep trying regardless. if !isStaticEdge { return } case connection.DupConnRegisterTunnelError, *quic.IdleTimeoutError, edgediscovery.DialError, *connection.EdgeQuicDialError: // Try again for these types of errors default: // Uncaught errors should bail startup return } } } // startTunnel starts a new tunnel connection. The resulting error will be sent on // s.tunnelError as this is expected to run in a goroutine. func (s *Supervisor) startTunnel( ctx context.Context, index int, connectedSignal *signal.Signal, ) { var ( err error ) defer func() { s.tunnelErrors <- tunnelError{index: index, err: err} }() err = s.edgeTunnelServer.Serve(ctx, uint8(index), s.tunnelsProtocolFallback[index], connectedSignal) } func (s *Supervisor) newConnectedTunnelSignal(index int) *signal.Signal { sig := make(chan struct{}) s.tunnelsConnecting[index] = sig s.nextConnectedSignal = sig s.nextConnectedIndex = index return signal.New(sig) } func (s *Supervisor) waitForNextTunnel(index int) bool { delete(s.tunnelsConnecting, index) s.nextConnectedSignal = nil for k, v := range s.tunnelsConnecting { s.nextConnectedIndex = k s.nextConnectedSignal = v return true } return false } func (s *Supervisor) unusedIPs() bool { return s.edgeIPs.AvailableAddrs() > s.config.HAConnections }