package origin import ( "bufio" "crypto/tls" "fmt" "github.com/google/uuid" "io" "net" "net/http" "net/url" "strconv" "strings" "time" "golang.org/x/net/context" "golang.org/x/sync/errgroup" "github.com/cloudflare/cloudflared/h2mux" "github.com/cloudflare/cloudflared/tunnelrpc" tunnelpogs "github.com/cloudflare/cloudflared/tunnelrpc/pogs" "github.com/cloudflare/cloudflared/validation" "github.com/cloudflare/cloudflared/websocket" raven "github.com/getsentry/raven-go" "github.com/pkg/errors" _ "github.com/prometheus/client_golang/prometheus" log "github.com/sirupsen/logrus" rpc "zombiezen.com/go/capnproto2/rpc" ) const ( dialTimeout = 15 * time.Second lbProbeUserAgentPrefix = "Mozilla/5.0 (compatible; Cloudflare-Traffic-Manager/1.0; +https://www.cloudflare.com/traffic-manager/;" TagHeaderNamePrefix = "Cf-Warp-Tag-" DuplicateConnectionError = "EDUPCONN" ) type TunnelConfig struct { EdgeAddrs []string OriginUrl string Hostname string OriginCert []byte TlsConfig *tls.Config ClientTlsConfig *tls.Config Retries uint HeartbeatInterval time.Duration MaxHeartbeats uint64 ClientID string BuildInfo *BuildInfo ReportedVersion string LBPool string Tags []tunnelpogs.Tag HAConnections int HTTPTransport http.RoundTripper Metrics *TunnelMetrics MetricsUpdateFreq time.Duration ProtocolLogger *log.Logger Logger *log.Logger IsAutoupdated bool GracePeriod time.Duration RunFromTerminal bool NoChunkedEncoding bool WSGI bool CompressionQuality uint64 } type dialError struct { cause error } func (e dialError) Error() string { return e.cause.Error() } type dupConnRegisterTunnelError struct{} func (e dupConnRegisterTunnelError) Error() string { return "already connected to this server" } type muxerShutdownError struct{} func (e muxerShutdownError) Error() string { return "muxer shutdown" } // RegisterTunnel error from server type serverRegisterTunnelError struct { cause error permanent bool } func (e serverRegisterTunnelError) Error() string { return e.cause.Error() } // RegisterTunnel error from client type clientRegisterTunnelError struct { cause error } func (e clientRegisterTunnelError) Error() string { return e.cause.Error() } 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: fmt.Sprintf("%s_%s", c.BuildInfo.GoOS, c.BuildInfo.GoArch), ExistingTunnelPolicy: policy, PoolName: c.LBPool, Tags: c.Tags, ConnectionID: connectionID, OriginLocalIP: OriginLocalIP, IsAutoupdated: c.IsAutoupdated, RunFromTerminal: c.RunFromTerminal, CompressionQuality: c.CompressionQuality, UUID: uuid.String(), } } func StartTunnelDaemon(config *TunnelConfig, shutdownC <-chan struct{}, connectedSignal chan struct{}) error { ctx, cancel := context.WithCancel(context.Background()) go func() { <-shutdownC cancel() }() // If a user specified negative HAConnections, we will treat it as requesting 1 connection if config.HAConnections > 1 { return NewSupervisor(config).Run(ctx, connectedSignal) } else { addrs, err := ResolveEdgeIPs(config.EdgeAddrs) if err != nil { return err } return ServeTunnelLoop(ctx, config, addrs[0], 0, connectedSignal) } } func ServeTunnelLoop(ctx context.Context, config *TunnelConfig, addr *net.TCPAddr, connectionID uint8, connectedSignal chan struct{}, ) error { logger := config.Logger config.Metrics.incrementHaConnections() defer config.Metrics.decrementHaConnections() backoff := BackoffHandler{MaxRetries: config.Retries} // Used to close connectedSignal no more than once connectedFuse := h2mux.NewBooleanFuse() go func() { if connectedFuse.Await() { close(connectedSignal) } }() // Ensure the above goroutine will terminate if we return without connecting defer connectedFuse.Fuse(false) for { err, recoverable := ServeTunnel(ctx, config, addr, connectionID, connectedFuse, &backoff) if recoverable { if duration, ok := backoff.GetBackoffDuration(ctx); ok { logger.Infof("Retrying in %s seconds", duration) backoff.Backoff(ctx) continue } } return err } } func ServeTunnel( ctx context.Context, config *TunnelConfig, addr *net.TCPAddr, connectionID uint8, connectedFuse *h2mux.BooleanFuse, backoff *BackoffHandler, ) (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) } recoverable = true } }() connectionTag := uint8ToString(connectionID) logger := config.Logger.WithField("connectionID", connectionTag) // additional tags to send other than hostname which is set in cloudflared main package tags := make(map[string]string) tags["ha"] = connectionTag // Returns error from parsing the origin URL or handshake errors handler, originLocalIP, err := NewTunnelHandler(ctx, config, addr.String(), connectionID) if err != nil { errLog := config.Logger.WithError(err) switch err.(type) { case dialError: errLog.Error("Unable to dial edge") case h2mux.MuxerHandshakeError: errLog.Error("Handshake failed with edge server") default: errLog.Error("Tunnel creation failure") return err, false } return err, true } errGroup, serveCtx := errgroup.WithContext(ctx) errGroup.Go(func() error { err := RegisterTunnel(serveCtx, handler.muxer, config, connectionID, originLocalIP) if err == nil { connectedFuse.Fuse(true) backoff.SetGracePeriod() } return err }) errGroup.Go(func() error { updateMetricsTickC := time.Tick(config.MetricsUpdateFreq) for { select { case <-serveCtx.Done(): // UnregisterTunnel blocks until the RPC call returns err := UnregisterTunnel(handler.muxer, config.GracePeriod, config.Logger) handler.muxer.Shutdown() return err case <-updateMetricsTickC: handler.UpdateMetrics(connectionTag) } } }) errGroup.Go(func() error { // All routines should stop when muxer finish serving. When muxer is shutdown // gracefully, it doesn't return an error, so we need to return errMuxerShutdown // here to notify other routines to stop err := handler.muxer.Serve(serveCtx) if err == nil { return muxerShutdownError{} } return err }) err = errGroup.Wait() if err != nil { switch castedErr := err.(type) { case dupConnRegisterTunnelError: logger.Info("Already connected to this server, selecting a different one") return err, true case serverRegisterTunnelError: logger.WithError(castedErr.cause).Error("Register tunnel error from server side") // Don't send registration error return from server to Sentry. They are // logged on server side return castedErr.cause, !castedErr.permanent case clientRegisterTunnelError: logger.WithError(castedErr.cause).Error("Register tunnel error on client side") raven.CaptureError(castedErr.cause, tags) return err, true case muxerShutdownError: logger.Infof("Muxer shutdown") return err, true default: logger.WithError(err).Error("Serve tunnel error") raven.CaptureError(err, tags) return err, true } } return nil, true } func IsRPCStreamResponse(headers []h2mux.Header) bool { if len(headers) != 1 { return false } if headers[0].Name != ":status" || headers[0].Value != "200" { return false } return true } func RegisterTunnel(ctx context.Context, muxer *h2mux.Muxer, config *TunnelConfig, connectionID uint8, originLocalIP string) error { config.Logger.Debug("initiating RPC stream to register") stream, err := muxer.OpenStream([]h2mux.Header{ {Name: ":method", Value: "RPC"}, {Name: ":scheme", Value: "capnp"}, {Name: ":path", Value: "*"}, }, nil) if err != nil { // RPC stream open error return clientRegisterTunnelError{cause: err} } if !IsRPCStreamResponse(stream.Headers) { // stream response error return clientRegisterTunnelError{cause: err} } conn := rpc.NewConn( tunnelrpc.NewTransportLogger(config.Logger.WithField("subsystem", "rpc-register"), rpc.StreamTransport(stream)), tunnelrpc.ConnLog(config.Logger.WithField("subsystem", "rpc-transport")), ) defer conn.Close() ts := tunnelpogs.TunnelServer_PogsClient{Client: conn.Bootstrap(ctx)} // Request server info without blocking tunnel registration; must use capnp library directly. tsClient := tunnelrpc.TunnelServer{Client: ts.Client} serverInfoPromise := tsClient.GetServerInfo(ctx, func(tunnelrpc.TunnelServer_getServerInfo_Params) error { return nil }) uuid, err := uuid.NewRandom() if err != nil { return clientRegisterTunnelError{cause: err} } registration, err := ts.RegisterTunnel( ctx, config.OriginCert, config.Hostname, config.RegistrationOptions(connectionID, originLocalIP, uuid), ) LogServerInfo(serverInfoPromise.Result(), connectionID, config.Metrics, config.Logger) if err != nil { // RegisterTunnel RPC failure return clientRegisterTunnelError{cause: err} } for _, logLine := range registration.LogLines { config.Logger.Info(logLine) } if registration.Err == DuplicateConnectionError { return dupConnRegisterTunnelError{} } else if registration.Err != "" { return serverRegisterTunnelError{ cause: fmt.Errorf("Server error: %s", registration.Err), permanent: registration.PermanentFailure, } } if registration.TunnelID != "" { config.Logger.Info("Tunnel ID: " + registration.TunnelID) } // Print out the user's trial zone URL in a nice box (if they requested and got one) if isTrialTunnel := config.Hostname == ""; isTrialTunnel { if url, err := url.Parse(registration.Url); err == nil { for _, line := range asciiBox(trialZoneMsg(url.String()), 2) { config.Logger.Infoln(line) } } else { config.Logger.Errorln("Failed to connect tunnel, please try again.") return fmt.Errorf("empty URL in response from Cloudflare edge") } } config.Logger.Infof("Route propagating, it may take up to 1 minute for your new route to become functional") return nil } func UnregisterTunnel(muxer *h2mux.Muxer, gracePeriod time.Duration, logger *log.Logger) error { logger.Debug("initiating RPC stream to unregister") stream, err := muxer.OpenStream([]h2mux.Header{ {Name: ":method", Value: "RPC"}, {Name: ":scheme", Value: "capnp"}, {Name: ":path", Value: "*"}, }, nil) if err != nil { // RPC stream open error return err } if !IsRPCStreamResponse(stream.Headers) { // stream response error return err } ctx := context.Background() conn := rpc.NewConn( tunnelrpc.NewTransportLogger(logger.WithField("subsystem", "rpc-unregister"), rpc.StreamTransport(stream)), tunnelrpc.ConnLog(logger.WithField("subsystem", "rpc-transport")), ) defer conn.Close() ts := tunnelpogs.TunnelServer_PogsClient{Client: conn.Bootstrap(ctx)} // gracePeriod is encoded in int64 using capnproto return ts.UnregisterTunnel(ctx, gracePeriod.Nanoseconds()) } func LogServerInfo( promise tunnelrpc.ServerInfo_Promise, connectionID uint8, metrics *TunnelMetrics, logger *log.Logger, ) { serverInfoMessage, err := promise.Struct() if err != nil { logger.WithError(err).Warn("Failed to retrieve server information") return } serverInfo, err := tunnelpogs.UnmarshalServerInfo(serverInfoMessage) if err != nil { logger.WithError(err).Warn("Failed to retrieve server information") return } logger.Infof("Connected to %s", serverInfo.LocationName) metrics.registerServerLocation(uint8ToString(connectionID), serverInfo.LocationName) } func H2RequestHeadersToH1Request(h2 []h2mux.Header, h1 *http.Request) error { for _, header := range h2 { switch header.Name { case ":method": h1.Method = header.Value case ":scheme": case ":authority": // Otherwise the host header will be based on the origin URL h1.Host = header.Value case ":path": u, err := url.Parse(header.Value) if err != nil { return fmt.Errorf("unparseable path") } resolved := h1.URL.ResolveReference(u) // prevent escaping base URL if !strings.HasPrefix(resolved.String(), h1.URL.String()) { return fmt.Errorf("invalid path") } h1.URL = resolved default: h1.Header.Add(http.CanonicalHeaderKey(header.Name), header.Value) } } return nil } func H1ResponseToH2Response(h1 *http.Response) (h2 []h2mux.Header) { h2 = []h2mux.Header{{Name: ":status", Value: fmt.Sprintf("%d", h1.StatusCode)}} for headerName, headerValues := range h1.Header { for _, headerValue := range headerValues { h2 = append(h2, h2mux.Header{Name: strings.ToLower(headerName), Value: headerValue}) } } return } func FindCfRayHeader(h1 *http.Request) string { return h1.Header.Get("Cf-Ray") } type TunnelHandler struct { originUrl string muxer *h2mux.Muxer httpClient http.RoundTripper tlsConfig *tls.Config tags []tunnelpogs.Tag metrics *TunnelMetrics // connectionID is only used by metrics, and prometheus requires labels to be string connectionID string logger *log.Logger noChunkedEncoding bool } var dialer = net.Dialer{DualStack: true} // NewTunnelHandler returns a TunnelHandler, origin LAN IP and error func NewTunnelHandler(ctx context.Context, config *TunnelConfig, addr string, connectionID uint8, ) (*TunnelHandler, string, error) { originURL, err := validation.ValidateUrl(config.OriginUrl) if err != nil { return nil, "", fmt.Errorf("unable to parse origin URL %#v", originURL) } h := &TunnelHandler{ originUrl: originURL, httpClient: config.HTTPTransport, tlsConfig: config.ClientTlsConfig, tags: config.Tags, metrics: config.Metrics, connectionID: uint8ToString(connectionID), logger: config.Logger, noChunkedEncoding: config.NoChunkedEncoding, } if h.httpClient == nil { h.httpClient = http.DefaultTransport } // Inherit from parent context so we can cancel (Ctrl-C) while dialing dialCtx, dialCancel := context.WithTimeout(ctx, dialTimeout) // TUN-92: enforce a timeout on dial and handshake (as tls.Dial does not support one) plaintextEdgeConn, err := dialer.DialContext(dialCtx, "tcp", addr) dialCancel() if err != nil { return nil, "", dialError{cause: errors.Wrap(err, "DialContext error")} } edgeConn := tls.Client(plaintextEdgeConn, config.TlsConfig) edgeConn.SetDeadline(time.Now().Add(dialTimeout)) err = edgeConn.Handshake() if err != nil { return nil, "", dialError{cause: errors.Wrap(err, "Handshake with edge error")} } // clear the deadline on the conn; h2mux has its own timeouts edgeConn.SetDeadline(time.Time{}) // Establish a muxed connection with the edge // Client mux handshake with agent server h.muxer, err = h2mux.Handshake(edgeConn, edgeConn, h2mux.MuxerConfig{ Timeout: 5 * time.Second, Handler: h, IsClient: true, HeartbeatInterval: config.HeartbeatInterval, MaxHeartbeats: config.MaxHeartbeats, Logger: config.ProtocolLogger.WithFields(log.Fields{}), CompressionQuality: h2mux.CompressionSetting(config.CompressionQuality), }) if err != nil { return h, "", errors.New("TLS handshake error") } return h, edgeConn.LocalAddr().String(), err } func (h *TunnelHandler) AppendTagHeaders(r *http.Request) { for _, tag := range h.tags { r.Header.Add(TagHeaderNamePrefix+tag.Name, tag.Value) } } func (h *TunnelHandler) ServeStream(stream *h2mux.MuxedStream) error { h.metrics.incrementRequests(h.connectionID) req, err := http.NewRequest("GET", h.originUrl, h2mux.MuxedStreamReader{MuxedStream: stream}) if err != nil { h.logger.WithError(err).Panic("Unexpected error from http.NewRequest") } err = H2RequestHeadersToH1Request(stream.Headers, req) if err != nil { h.logger.WithError(err).Error("invalid request received") } h.AppendTagHeaders(req) cfRay := FindCfRayHeader(req) lbProbe := isLBProbeRequest(req) h.logRequest(req, cfRay, lbProbe) if websocket.IsWebSocketUpgrade(req) { conn, response, err := websocket.ClientConnect(req, h.tlsConfig) if err != nil { h.logError(stream, err) } else { stream.WriteHeaders(H1ResponseToH2Response(response)) defer conn.Close() // Copy to/from stream to the undelying connection. Use the underlying // connection because cloudflared doesn't operate on the message themselves websocket.Stream(conn.UnderlyingConn(), stream) h.metrics.incrementResponses(h.connectionID, "200") h.logResponse(response, cfRay, lbProbe) } } else { // Support for WSGI Servers by switching transfer encoding from chunked to gzip/deflate if h.noChunkedEncoding { req.TransferEncoding = []string{"gzip", "deflate"} cLength, err := strconv.Atoi(req.Header.Get("Content-Length")) if err == nil { req.ContentLength = int64(cLength) } } // Request origin to keep connection alive to improve performance req.Header.Set("Connection", "keep-alive") response, err := h.httpClient.RoundTrip(req) if err != nil { h.logError(stream, err) } else { defer response.Body.Close() stream.WriteHeaders(H1ResponseToH2Response(response)) if h.isEventStream(response) { h.writeEventStream(stream, response.Body) } else { // Use CopyBuffer, because Copy only allocates a 32KiB buffer, and cross-stream // compression generates dictionary on first write io.CopyBuffer(stream, response.Body, make([]byte, 512*1024)) } h.metrics.incrementResponses(h.connectionID, "200") h.logResponse(response, cfRay, lbProbe) } } h.metrics.decrementConcurrentRequests(h.connectionID) return nil } func (h *TunnelHandler) writeEventStream(stream *h2mux.MuxedStream, responseBody io.ReadCloser) { reader := bufio.NewReader(responseBody) for { line, err := reader.ReadBytes('\n') if err != nil { break } stream.Write(line) } } func (h *TunnelHandler) isEventStream(response *http.Response) bool { if response.Header.Get("content-type") == "text/event-stream" { h.logger.Debug("Detected Server-Side Events from Origin") return true } return false } func (h *TunnelHandler) logError(stream *h2mux.MuxedStream, err error) { h.logger.WithError(err).Error("HTTP request error") stream.WriteHeaders([]h2mux.Header{{Name: ":status", Value: "502"}}) stream.Write([]byte("502 Bad Gateway")) h.metrics.incrementResponses(h.connectionID, "502") } func (h *TunnelHandler) logRequest(req *http.Request, cfRay string, lbProbe bool) { if cfRay != "" { h.logger.WithField("CF-RAY", cfRay).Debugf("%s %s %s", req.Method, req.URL, req.Proto) } else if lbProbe { h.logger.Debugf("Load Balancer health check %s %s %s", req.Method, req.URL, req.Proto) } else { h.logger.Warnf("All requests should have a CF-RAY header. Please open a support ticket with Cloudflare. %s %s %s ", req.Method, req.URL, req.Proto) } h.logger.Debugf("Request Headers %+v", req.Header) } func (h *TunnelHandler) logResponse(r *http.Response, cfRay string, lbProbe bool) { if cfRay != "" { h.logger.WithField("CF-RAY", cfRay).Debugf("%s", r.Status) } else if lbProbe { h.logger.Debugf("Response to Load Balancer health check %s", r.Status) } else { h.logger.Infof("%s", r.Status) } h.logger.Debugf("Response Headers %+v", r.Header) } func (h *TunnelHandler) UpdateMetrics(connectionID string) { h.metrics.updateMuxerMetrics(connectionID, h.muxer.Metrics()) } func uint8ToString(input uint8) string { return strconv.FormatUint(uint64(input), 10) } func isLBProbeRequest(req *http.Request) bool { return strings.HasPrefix(req.UserAgent(), lbProbeUserAgentPrefix) } // Print out the given lines in a nice ASCII box. func asciiBox(lines []string, padding int) (box []string) { maxLen := maxLen(lines) spacer := strings.Repeat(" ", padding) border := "+" + strings.Repeat("-", maxLen+(padding*2)) + "+" box = append(box, border) for _, line := range lines { box = append(box, "|"+spacer+line+strings.Repeat(" ", maxLen-len(line))+spacer+"|") } box = append(box, border) return } func maxLen(lines []string) int { max := 0 for _, line := range lines { if len(line) > max { max = len(line) } } return max } func trialZoneMsg(url string) []string { return []string{ "Your free tunnel has started! Visit it:", " " + url, } }