package origin import ( "context" "crypto/tls" "fmt" "net" "runtime/debug" "strings" "sync" "time" "github.com/google/uuid" "github.com/pkg/errors" "github.com/rs/zerolog" "golang.org/x/sync/errgroup" "github.com/cloudflare/cloudflared/connection" "github.com/cloudflare/cloudflared/edgediscovery" "github.com/cloudflare/cloudflared/h2mux" "github.com/cloudflare/cloudflared/signal" "github.com/cloudflare/cloudflared/tunnelrpc" tunnelpogs "github.com/cloudflare/cloudflared/tunnelrpc/pogs" ) const ( dialTimeout = 15 * time.Second lbProbeUserAgentPrefix = "Mozilla/5.0 (compatible; Cloudflare-Traffic-Manager/1.0; +https://www.cloudflare.com/traffic-manager/;" FeatureSerializedHeaders = "serialized_headers" FeatureQuickReconnects = "quick_reconnects" ) type rpcName string const ( reconnect rpcName = "reconnect" authenticate rpcName = " authenticate" ) type TunnelConfig struct { ConnectionConfig *connection.Config OSArch string ClientID string CloseConnOnce *sync.Once // Used to close connectedSignal no more than once EdgeAddrs []string HAConnections int IncidentLookup IncidentLookup IsAutoupdated bool IsFreeTunnel bool LBPool string Tags []tunnelpogs.Tag Log *zerolog.Logger LogTransport *zerolog.Logger Observer *connection.Observer ReportedVersion string Retries uint RunFromTerminal bool NamedTunnel *connection.NamedTunnelConfig ClassicTunnel *connection.ClassicTunnelConfig MuxerConfig *connection.MuxerConfig ProtocolSelector connection.ProtocolSelector EdgeTLSConfigs map[connection.Protocol]*tls.Config } func (c *TunnelConfig) RegistrationOptions(connectionID uint8, OriginLocalIP string, uuid uuid.UUID) *tunnelpogs.RegistrationOptions { policy := tunnelrpc.ExistingTunnelPolicy_balance if c.HAConnections <= 1 && c.LBPool == "" { policy = tunnelrpc.ExistingTunnelPolicy_disconnect } return &tunnelpogs.RegistrationOptions{ ClientID: c.ClientID, Version: c.ReportedVersion, OS: c.OSArch, ExistingTunnelPolicy: policy, PoolName: c.LBPool, Tags: c.Tags, ConnectionID: connectionID, OriginLocalIP: OriginLocalIP, IsAutoupdated: c.IsAutoupdated, RunFromTerminal: c.RunFromTerminal, CompressionQuality: uint64(c.MuxerConfig.CompressionSetting), UUID: uuid.String(), Features: c.SupportedFeatures(), } } func (c *TunnelConfig) ConnectionOptions(originLocalAddr string, numPreviousAttempts uint8) *tunnelpogs.ConnectionOptions { // attempt to parse out origin IP, but don't fail since it's informational field host, _, _ := net.SplitHostPort(originLocalAddr) originIP := net.ParseIP(host) return &tunnelpogs.ConnectionOptions{ Client: c.NamedTunnel.Client, OriginLocalIP: originIP, ReplaceExisting: c.ConnectionConfig.ReplaceExisting, CompressionQuality: uint8(c.MuxerConfig.CompressionSetting), NumPreviousAttempts: numPreviousAttempts, } } func (c *TunnelConfig) SupportedFeatures() []string { features := []string{FeatureSerializedHeaders} if c.NamedTunnel == nil { features = append(features, FeatureQuickReconnects) } return features } func StartTunnelDaemon( ctx context.Context, config *TunnelConfig, connectedSignal *signal.Signal, reconnectCh chan ReconnectSignal, graceShutdownC <-chan struct{}, ) error { s, err := NewSupervisor(config, reconnectCh, graceShutdownC) if err != nil { return err } return s.Run(ctx, connectedSignal) } func ServeTunnelLoop( ctx context.Context, credentialManager *reconnectCredentialManager, config *TunnelConfig, addr *net.TCPAddr, connIndex uint8, connectedSignal *signal.Signal, cloudflaredUUID uuid.UUID, reconnectCh chan ReconnectSignal, gracefulShutdownC <-chan struct{}, ) error { haConnections.Inc() defer haConnections.Dec() connLog := config.Log.With().Uint8(connection.LogFieldConnIndex, connIndex).Logger() protocolFallback := &protocolFallback{ BackoffHandler{MaxRetries: config.Retries}, config.ProtocolSelector.Current(), false, } connectedFuse := h2mux.NewBooleanFuse() go func() { if connectedFuse.Await() { connectedSignal.Notify() } }() // Ensure the above goroutine will terminate if we return without connecting defer connectedFuse.Fuse(false) // Each connection to keep its own copy of protocol, because individual connections might fallback // to another protocol when a particular metal doesn't support new protocol for { err, recoverable := ServeTunnel( ctx, &connLog, credentialManager, config, addr, connIndex, connectedFuse, protocolFallback, cloudflaredUUID, reconnectCh, protocolFallback.protocol, gracefulShutdownC, ) if !recoverable { return err } config.Observer.SendReconnect(connIndex) duration, ok := protocolFallback.GetMaxBackoffDuration(ctx) if !ok { return err } connLog.Info().Msgf("Retrying connection in up to %s seconds", duration) select { case <-ctx.Done(): return ctx.Err() case <-gracefulShutdownC: return nil case <-protocolFallback.BackoffTimer(): if !selectNextProtocol(&connLog, protocolFallback, config.ProtocolSelector) { return err } } } } // protocolFallback is a wrapper around backoffHandler that will try fallback option when backoff reaches // max retries type protocolFallback struct { BackoffHandler protocol connection.Protocol inFallback bool } func (pf *protocolFallback) reset() { pf.resetNow() pf.inFallback = false } func (pf *protocolFallback) fallback(fallback connection.Protocol) { pf.resetNow() pf.protocol = fallback pf.inFallback = true } // selectNextProtocol picks connection protocol for the next retry iteration, // returns true if it was able to pick the protocol, false if we are out of options and should stop retrying func selectNextProtocol( connLog *zerolog.Logger, protocolBackoff *protocolFallback, selector connection.ProtocolSelector, ) bool { if protocolBackoff.ReachedMaxRetries() { fallback, hasFallback := selector.Fallback() if !hasFallback { return false } // Already using fallback protocol, no point to retry if protocolBackoff.protocol == fallback { return false } connLog.Info().Msgf("Switching to fallback protocol %s", fallback) protocolBackoff.fallback(fallback) } else if !protocolBackoff.inFallback { current := selector.Current() if protocolBackoff.protocol != current { protocolBackoff.protocol = current connLog.Info().Msgf("Changing protocol to %s", current) } } return true } // ServeTunnel runs a single tunnel connection, returns nil on graceful shutdown, // on error returns a flag indicating if error can be retried func ServeTunnel( ctx context.Context, connLog *zerolog.Logger, credentialManager *reconnectCredentialManager, config *TunnelConfig, addr *net.TCPAddr, connIndex uint8, fuse *h2mux.BooleanFuse, backoff *protocolFallback, cloudflaredUUID uuid.UUID, reconnectCh chan ReconnectSignal, protocol connection.Protocol, gracefulShutdownC <-chan struct{}, ) (err error, recoverable bool) { // Treat panics as recoverable errors defer func() { if r := recover(); r != nil { var ok bool err, ok = r.(error) if !ok { err = fmt.Errorf("ServeTunnel: %v", r) } err = errors.Wrapf(err, "stack trace: %s", string(debug.Stack())) recoverable = true } }() defer config.Observer.SendDisconnect(connIndex) edgeConn, err := edgediscovery.DialEdge(ctx, dialTimeout, config.EdgeTLSConfigs[protocol], addr) if err != nil { connLog.Err(err).Msg("Unable to establish connection with Cloudflare edge") return err, true } connectedFuse := &connectedFuse{ fuse: fuse, backoff: backoff, } if protocol == connection.HTTP2 { connOptions := config.ConnectionOptions(edgeConn.LocalAddr().String(), uint8(backoff.retries)) err = ServeHTTP2( ctx, connLog, config, edgeConn, connOptions, connIndex, connectedFuse, reconnectCh, gracefulShutdownC, ) } else { err = ServeH2mux( ctx, connLog, credentialManager, config, edgeConn, connIndex, connectedFuse, cloudflaredUUID, reconnectCh, gracefulShutdownC, ) } if err != nil { switch err := err.(type) { case connection.DupConnRegisterTunnelError: connLog.Err(err).Msg("Unable to establish connection.") // don't retry this connection anymore, let supervisor pick a new address return err, false case connection.ServerRegisterTunnelError: connLog.Err(err).Msg("Register tunnel error from server side") // Don't send registration error return from server to Sentry. They are // logged on server side if incidents := config.IncidentLookup.ActiveIncidents(); len(incidents) > 0 { connLog.Error().Msg(activeIncidentsMsg(incidents)) } return err.Cause, !err.Permanent case ReconnectSignal: connLog.Info(). Uint8(connection.LogFieldConnIndex, connIndex). Msgf("Restarting connection due to reconnect signal in %s", err.Delay) err.DelayBeforeReconnect() return err, true default: if err == context.Canceled { connLog.Debug().Err(err).Msgf("Serve tunnel error") return err, false } connLog.Err(err).Msgf("Serve tunnel error") _, permanent := err.(unrecoverableError) return err, !permanent } } return nil, false } type unrecoverableError struct { err error } func (r unrecoverableError) Error() string { return r.err.Error() } func ServeH2mux( ctx context.Context, connLog *zerolog.Logger, credentialManager *reconnectCredentialManager, config *TunnelConfig, edgeConn net.Conn, connIndex uint8, connectedFuse *connectedFuse, cloudflaredUUID uuid.UUID, reconnectCh chan ReconnectSignal, gracefulShutdownC <-chan struct{}, ) error { connLog.Debug().Msgf("Connecting via h2mux") // Returns error from parsing the origin URL or handshake errors handler, err, recoverable := connection.NewH2muxConnection( config.ConnectionConfig, config.MuxerConfig, edgeConn, connIndex, config.Observer, gracefulShutdownC, ) if err != nil { if !recoverable { return unrecoverableError{err} } return err } errGroup, serveCtx := errgroup.WithContext(ctx) errGroup.Go(func() error { if config.NamedTunnel != nil { connOptions := config.ConnectionOptions(edgeConn.LocalAddr().String(), uint8(connectedFuse.backoff.retries)) return handler.ServeNamedTunnel(serveCtx, config.NamedTunnel, connOptions, connectedFuse) } registrationOptions := config.RegistrationOptions(connIndex, edgeConn.LocalAddr().String(), cloudflaredUUID) return handler.ServeClassicTunnel(serveCtx, config.ClassicTunnel, credentialManager, registrationOptions, connectedFuse) }) errGroup.Go(func() error { return listenReconnect(serveCtx, reconnectCh, gracefulShutdownC) }) return errGroup.Wait() } func ServeHTTP2( ctx context.Context, connLog *zerolog.Logger, config *TunnelConfig, tlsServerConn net.Conn, connOptions *tunnelpogs.ConnectionOptions, connIndex uint8, connectedFuse connection.ConnectedFuse, reconnectCh chan ReconnectSignal, gracefulShutdownC <-chan struct{}, ) error { connLog.Debug().Msgf("Connecting via http2") h2conn := connection.NewHTTP2Connection( tlsServerConn, config.ConnectionConfig, config.NamedTunnel, connOptions, config.Observer, connIndex, connectedFuse, gracefulShutdownC, ) errGroup, serveCtx := errgroup.WithContext(ctx) errGroup.Go(func() error { return h2conn.Serve(serveCtx) }) errGroup.Go(func() error { err := listenReconnect(serveCtx, reconnectCh, gracefulShutdownC) if err != nil { // forcefully break the connection (this is only used for testing) _ = tlsServerConn.Close() } return err }) return errGroup.Wait() } func listenReconnect(ctx context.Context, reconnectCh <-chan ReconnectSignal, gracefulShutdownCh <-chan struct{}) error { select { case reconnect := <-reconnectCh: return reconnect case <-gracefulShutdownCh: return nil case <-ctx.Done(): return nil } } type connectedFuse struct { fuse *h2mux.BooleanFuse backoff *protocolFallback } func (cf *connectedFuse) Connected() { cf.fuse.Fuse(true) cf.backoff.reset() } func (cf *connectedFuse) IsConnected() bool { return cf.fuse.Value() } func activeIncidentsMsg(incidents []Incident) string { preamble := "There is an active Cloudflare incident that may be related:" if len(incidents) > 1 { preamble = "There are active Cloudflare incidents that may be related:" } incidentStrings := []string{} for _, incident := range incidents { incidentString := fmt.Sprintf("%s (%s)", incident.Name, incident.URL()) incidentStrings = append(incidentStrings, incidentString) } return preamble + " " + strings.Join(incidentStrings, "; ") }