package connection import ( "bufio" "context" "crypto/tls" "fmt" "io" "net" "net/http" "net/netip" "strconv" "strings" "sync" "sync/atomic" "time" "github.com/google/uuid" "github.com/pkg/errors" "github.com/quic-go/quic-go" "github.com/rs/zerolog" "go.opentelemetry.io/otel/attribute" "go.opentelemetry.io/otel/trace" "golang.org/x/sync/errgroup" "github.com/cloudflare/cloudflared/datagramsession" "github.com/cloudflare/cloudflared/ingress" "github.com/cloudflare/cloudflared/management" "github.com/cloudflare/cloudflared/packet" quicpogs "github.com/cloudflare/cloudflared/quic" "github.com/cloudflare/cloudflared/tracing" tunnelpogs "github.com/cloudflare/cloudflared/tunnelrpc/pogs" ) const ( // HTTPHeaderKey is used to get or set http headers in QUIC ALPN if the underlying proxy connection type is HTTP. HTTPHeaderKey = "HttpHeader" // HTTPMethodKey is used to get or set http method in QUIC ALPN if the underlying proxy connection type is HTTP. HTTPMethodKey = "HttpMethod" // HTTPHostKey is used to get or set http Method in QUIC ALPN if the underlying proxy connection type is HTTP. HTTPHostKey = "HttpHost" QUICMetadataFlowID = "FlowID" // emperically this capacity has been working well demuxChanCapacity = 16 ) var ( portForConnIndex = make(map[uint8]int, 0) portMapMutex sync.Mutex ) // QUICConnection represents the type that facilitates Proxying via QUIC streams. type QUICConnection struct { session quic.Connection logger *zerolog.Logger orchestrator Orchestrator // sessionManager tracks active sessions. It receives datagrams from quic connection via datagramMuxer sessionManager datagramsession.Manager // datagramMuxer mux/demux datagrams from quic connection datagramMuxer *quicpogs.DatagramMuxerV2 packetRouter *ingress.PacketRouter controlStreamHandler ControlStreamHandler connOptions *tunnelpogs.ConnectionOptions connIndex uint8 udpUnregisterTimeout time.Duration } // NewQUICConnection returns a new instance of QUICConnection. func NewQUICConnection( ctx context.Context, quicConfig *quic.Config, edgeAddr net.Addr, localAddr net.IP, connIndex uint8, tlsConfig *tls.Config, orchestrator Orchestrator, connOptions *tunnelpogs.ConnectionOptions, controlStreamHandler ControlStreamHandler, logger *zerolog.Logger, packetRouterConfig *ingress.GlobalRouterConfig, udpUnregisterTimeout time.Duration, ) (*QUICConnection, error) { udpConn, err := createUDPConnForConnIndex(connIndex, localAddr, logger) if err != nil { return nil, err } session, err := quic.Dial(ctx, udpConn, edgeAddr, tlsConfig, quicConfig) if err != nil { // close the udp server socket in case of error connecting to the edge udpConn.Close() return nil, &EdgeQuicDialError{Cause: err} } // wrap the session, so that the UDPConn is closed after session is closed. session = &wrapCloseableConnQuicConnection{ session, udpConn, } sessionDemuxChan := make(chan *packet.Session, demuxChanCapacity) datagramMuxer := quicpogs.NewDatagramMuxerV2(session, logger, sessionDemuxChan) sessionManager := datagramsession.NewManager(logger, datagramMuxer.SendToSession, sessionDemuxChan) packetRouter := ingress.NewPacketRouter(packetRouterConfig, datagramMuxer, logger, orchestrator.WarpRoutingEnabled) return &QUICConnection{ session: session, orchestrator: orchestrator, logger: logger, sessionManager: sessionManager, datagramMuxer: datagramMuxer, packetRouter: packetRouter, controlStreamHandler: controlStreamHandler, connOptions: connOptions, connIndex: connIndex, udpUnregisterTimeout: udpUnregisterTimeout, }, nil } // Serve starts a QUIC session that begins accepting streams. func (q *QUICConnection) Serve(ctx context.Context) error { // origintunneld assumes the first stream is used for the control plane controlStream, err := q.session.OpenStream() if err != nil { return fmt.Errorf("failed to open a registration control stream: %w", err) } // If either goroutine returns nil error, we rely on this cancellation to make sure the other goroutine exits // as fast as possible as well. Nil error means we want to exit for good (caller code won't retry serving this // connection). // If either goroutine returns a non nil error, then the error group cancels the context, thus also canceling the // other goroutine as fast as possible. ctx, cancel := context.WithCancel(ctx) errGroup, ctx := errgroup.WithContext(ctx) // In the future, if cloudflared can autonomously push traffic to the edge, we have to make sure the control // stream is already fully registered before the other goroutines can proceed. errGroup.Go(func() error { defer cancel() return q.serveControlStream(ctx, controlStream) }) errGroup.Go(func() error { defer cancel() return q.acceptStream(ctx) }) errGroup.Go(func() error { defer cancel() return q.sessionManager.Serve(ctx) }) errGroup.Go(func() error { defer cancel() return q.datagramMuxer.ServeReceive(ctx) }) errGroup.Go(func() error { defer cancel() return q.packetRouter.Serve(ctx) }) return errGroup.Wait() } func (q *QUICConnection) serveControlStream(ctx context.Context, controlStream quic.Stream) error { // This blocks until the control plane is done. err := q.controlStreamHandler.ServeControlStream(ctx, controlStream, q.connOptions, q.orchestrator) if err != nil { // Not wrapping error here to be consistent with the http2 message. return err } return nil } // Close closes the session with no errors specified. func (q *QUICConnection) Close() { q.session.CloseWithError(0, "") } func (q *QUICConnection) acceptStream(ctx context.Context) error { defer q.Close() for { quicStream, err := q.session.AcceptStream(ctx) if err != nil { // context.Canceled is usually a user ctrl+c. We don't want to log an error here as it's intentional. if errors.Is(err, context.Canceled) || q.controlStreamHandler.IsStopped() { return nil } return fmt.Errorf("failed to accept QUIC stream: %w", err) } go q.runStream(quicStream) } } func (q *QUICConnection) runStream(quicStream quic.Stream) { ctx := quicStream.Context() stream := quicpogs.NewSafeStreamCloser(quicStream) defer stream.Close() // we are going to fuse readers/writers from stream <- cloudflared -> origin, and we want to guarantee that // code executed in the code path of handleStream don't trigger an earlier close to the downstream write stream. // So, we wrap the stream with a no-op write closer and only this method can actually close write side of the stream. // A call to close will simulate a close to the read-side, which will fail subsequent reads. noCloseStream := &nopCloserReadWriter{ReadWriteCloser: stream} if err := q.handleStream(ctx, noCloseStream); err != nil { q.logger.Debug().Err(err).Msg("Failed to handle QUIC stream") // if we received an error at this level, then close write side of stream with an error, which will result in // RST_STREAM frame. quicStream.CancelWrite(0) } } func (q *QUICConnection) handleStream(ctx context.Context, stream io.ReadWriteCloser) error { signature, err := quicpogs.DetermineProtocol(stream) if err != nil { return err } switch signature { case quicpogs.DataStreamProtocolSignature: reqServerStream, err := quicpogs.NewRequestServerStream(stream, signature) if err != nil { return err } return q.handleDataStream(ctx, reqServerStream) case quicpogs.RPCStreamProtocolSignature: rpcStream, err := quicpogs.NewRPCServerStream(stream, signature) if err != nil { return err } return q.handleRPCStream(rpcStream) default: return fmt.Errorf("unknown protocol %v", signature) } } func (q *QUICConnection) handleDataStream(ctx context.Context, stream *quicpogs.RequestServerStream) error { request, err := stream.ReadConnectRequestData() if err != nil { return err } if err, connectResponseSent := q.dispatchRequest(ctx, stream, err, request); err != nil { q.logger.Err(err).Str("type", request.Type.String()).Str("dest", request.Dest).Msg("Request failed") // if the connectResponse was already sent and we had an error, we need to propagate it up, so that the stream is // closed with an RST_STREAM frame if connectResponseSent { return err } if writeRespErr := stream.WriteConnectResponseData(err); writeRespErr != nil { return writeRespErr } } return nil } // dispatchRequest will dispatch the request depending on the type and returns an error if it occurs. // More importantly, it also tells if the during processing of the request the ConnectResponse metadata was sent downstream. // This is important since it informs func (q *QUICConnection) dispatchRequest(ctx context.Context, stream *quicpogs.RequestServerStream, err error, request *quicpogs.ConnectRequest) (error, bool) { originProxy, err := q.orchestrator.GetOriginProxy() if err != nil { return err, false } switch request.Type { case quicpogs.ConnectionTypeHTTP, quicpogs.ConnectionTypeWebsocket: tracedReq, err := buildHTTPRequest(ctx, request, stream, q.connIndex, q.logger) if err != nil { return err, false } w := newHTTPResponseAdapter(stream) return originProxy.ProxyHTTP(&w, tracedReq, request.Type == quicpogs.ConnectionTypeWebsocket), w.connectResponseSent case quicpogs.ConnectionTypeTCP: rwa := &streamReadWriteAcker{RequestServerStream: stream} metadata := request.MetadataMap() return originProxy.ProxyTCP(ctx, rwa, &TCPRequest{ Dest: request.Dest, FlowID: metadata[QUICMetadataFlowID], CfTraceID: metadata[tracing.TracerContextName], ConnIndex: q.connIndex, }), rwa.connectResponseSent default: return errors.Errorf("unsupported error type: %s", request.Type), false } } func (q *QUICConnection) handleRPCStream(rpcStream *quicpogs.RPCServerStream) error { if err := rpcStream.Serve(q, q, q.logger); err != nil { q.logger.Err(err).Msg("failed handling RPC stream") } return nil } // RegisterUdpSession is the RPC method invoked by edge to register and run a session func (q *QUICConnection) RegisterUdpSession(ctx context.Context, sessionID uuid.UUID, dstIP net.IP, dstPort uint16, closeAfterIdleHint time.Duration, traceContext string) (*tunnelpogs.RegisterUdpSessionResponse, error) { traceCtx := tracing.NewTracedContext(ctx, traceContext, q.logger) ctx, registerSpan := traceCtx.Tracer().Start(traceCtx, "register-session", trace.WithAttributes( attribute.String("session-id", sessionID.String()), attribute.String("dst", fmt.Sprintf("%s:%d", dstIP, dstPort)), )) log := q.logger.With().Int(management.EventTypeKey, int(management.UDP)).Logger() // Each session is a series of datagram from an eyeball to a dstIP:dstPort. // (src port, dst IP, dst port) uniquely identifies a session, so it needs a dedicated connected socket. originProxy, err := ingress.DialUDP(dstIP, dstPort) if err != nil { log.Err(err).Msgf("Failed to create udp proxy to %s:%d", dstIP, dstPort) tracing.EndWithErrorStatus(registerSpan, err) return nil, err } registerSpan.SetAttributes( attribute.Bool("socket-bind-success", true), attribute.String("src", originProxy.LocalAddr().String()), ) session, err := q.sessionManager.RegisterSession(ctx, sessionID, originProxy) if err != nil { log.Err(err).Str("sessionID", sessionID.String()).Msgf("Failed to register udp session") tracing.EndWithErrorStatus(registerSpan, err) return nil, err } go q.serveUDPSession(session, closeAfterIdleHint) log.Debug(). Str("sessionID", sessionID.String()). Str("src", originProxy.LocalAddr().String()). Str("dst", fmt.Sprintf("%s:%d", dstIP, dstPort)). Msgf("Registered session") tracing.End(registerSpan) resp := tunnelpogs.RegisterUdpSessionResponse{ Spans: traceCtx.GetProtoSpans(), } return &resp, nil } func (q *QUICConnection) serveUDPSession(session *datagramsession.Session, closeAfterIdleHint time.Duration) { ctx := q.session.Context() closedByRemote, err := session.Serve(ctx, closeAfterIdleHint) // If session is terminated by remote, then we know it has been unregistered from session manager and edge if !closedByRemote { if err != nil { q.closeUDPSession(ctx, session.ID, err.Error()) } else { q.closeUDPSession(ctx, session.ID, "terminated without error") } } q.logger.Debug().Err(err). Int(management.EventTypeKey, int(management.UDP)). Str("sessionID", session.ID.String()). Msg("Session terminated") } // closeUDPSession first unregisters the session from session manager, then it tries to unregister from edge func (q *QUICConnection) closeUDPSession(ctx context.Context, sessionID uuid.UUID, message string) { q.sessionManager.UnregisterSession(ctx, sessionID, message, false) quicStream, err := q.session.OpenStream() if err != nil { // Log this at debug because this is not an error if session was closed due to lost connection // with edge q.logger.Debug().Err(err). Int(management.EventTypeKey, int(management.UDP)). Str("sessionID", sessionID.String()). Msgf("Failed to open quic stream to unregister udp session with edge") return } stream := quicpogs.NewSafeStreamCloser(quicStream) defer stream.Close() rpcClientStream, err := quicpogs.NewRPCClientStream(ctx, stream, q.udpUnregisterTimeout, q.logger) if err != nil { // Log this at debug because this is not an error if session was closed due to lost connection // with edge q.logger.Err(err).Str("sessionID", sessionID.String()). Msgf("Failed to open rpc stream to unregister udp session with edge") return } defer rpcClientStream.Close() if err := rpcClientStream.UnregisterUdpSession(ctx, sessionID, message); err != nil { q.logger.Err(err).Str("sessionID", sessionID.String()). Msgf("Failed to unregister udp session with edge") } } // UnregisterUdpSession is the RPC method invoked by edge to unregister and terminate a sesssion func (q *QUICConnection) UnregisterUdpSession(ctx context.Context, sessionID uuid.UUID, message string) error { return q.sessionManager.UnregisterSession(ctx, sessionID, message, true) } // UpdateConfiguration is the RPC method invoked by edge when there is a new configuration func (q *QUICConnection) UpdateConfiguration(ctx context.Context, version int32, config []byte) *tunnelpogs.UpdateConfigurationResponse { return q.orchestrator.UpdateConfig(version, config) } // streamReadWriteAcker is a light wrapper over QUIC streams with a callback to send response back to // the client. type streamReadWriteAcker struct { *quicpogs.RequestServerStream connectResponseSent bool } // AckConnection acks response back to the proxy. func (s *streamReadWriteAcker) AckConnection(tracePropagation string) error { metadata := []quicpogs.Metadata{} // Only add tracing if provided by origintunneld if tracePropagation != "" { metadata = append(metadata, quicpogs.Metadata{ Key: tracing.CanonicalCloudflaredTracingHeader, Val: tracePropagation, }) } s.connectResponseSent = true return s.WriteConnectResponseData(nil, metadata...) } // httpResponseAdapter translates responses written by the HTTP Proxy into ones that can be used in QUIC. type httpResponseAdapter struct { *quicpogs.RequestServerStream headers http.Header connectResponseSent bool } func newHTTPResponseAdapter(s *quicpogs.RequestServerStream) httpResponseAdapter { return httpResponseAdapter{RequestServerStream: s, headers: make(http.Header)} } func (hrw *httpResponseAdapter) AddTrailer(trailerName, trailerValue string) { // we do not support trailers over QUIC } func (hrw *httpResponseAdapter) WriteRespHeaders(status int, header http.Header) error { metadata := make([]quicpogs.Metadata, 0) metadata = append(metadata, quicpogs.Metadata{Key: "HttpStatus", Val: strconv.Itoa(status)}) for k, vv := range header { for _, v := range vv { httpHeaderKey := fmt.Sprintf("%s:%s", HTTPHeaderKey, k) metadata = append(metadata, quicpogs.Metadata{Key: httpHeaderKey, Val: v}) } } return hrw.WriteConnectResponseData(nil, metadata...) } func (hrw *httpResponseAdapter) Write(p []byte) (int, error) { // Make sure to send WriteHeader response if not called yet if !hrw.connectResponseSent { hrw.WriteRespHeaders(http.StatusOK, hrw.headers) } return hrw.RequestServerStream.Write(p) } func (hrw *httpResponseAdapter) Header() http.Header { return hrw.headers } func (hrw *httpResponseAdapter) WriteHeader(status int) { hrw.WriteRespHeaders(status, hrw.headers) } func (hrw *httpResponseAdapter) Hijack() (net.Conn, *bufio.ReadWriter, error) { conn := &localProxyConnection{hrw.ReadWriteCloser} readWriter := bufio.NewReadWriter( bufio.NewReader(hrw.ReadWriteCloser), bufio.NewWriter(hrw.ReadWriteCloser), ) return conn, readWriter, nil } func (hrw *httpResponseAdapter) WriteErrorResponse(err error) { hrw.WriteConnectResponseData(err, quicpogs.Metadata{Key: "HttpStatus", Val: strconv.Itoa(http.StatusBadGateway)}) } func (hrw *httpResponseAdapter) WriteConnectResponseData(respErr error, metadata ...quicpogs.Metadata) error { hrw.connectResponseSent = true return hrw.RequestServerStream.WriteConnectResponseData(respErr, metadata...) } func buildHTTPRequest( ctx context.Context, connectRequest *quicpogs.ConnectRequest, body io.ReadCloser, connIndex uint8, log *zerolog.Logger, ) (*tracing.TracedHTTPRequest, error) { metadata := connectRequest.MetadataMap() dest := connectRequest.Dest method := metadata[HTTPMethodKey] host := metadata[HTTPHostKey] isWebsocket := connectRequest.Type == quicpogs.ConnectionTypeWebsocket req, err := http.NewRequestWithContext(ctx, method, dest, body) if err != nil { return nil, err } req.Host = host for _, metadata := range connectRequest.Metadata { if strings.Contains(metadata.Key, HTTPHeaderKey) { // metadata.Key is off the format httpHeaderKey: httpHeaderKey := strings.Split(metadata.Key, ":") if len(httpHeaderKey) != 2 { return nil, fmt.Errorf("header Key: %s malformed", metadata.Key) } req.Header.Add(httpHeaderKey[1], metadata.Val) } } // Go's http.Client automatically sends chunked request body if this value is not set on the // *http.Request struct regardless of header: // https://go.googlesource.com/go/+/go1.8rc2/src/net/http/transfer.go#154. if err := setContentLength(req); err != nil { return nil, fmt.Errorf("Error setting content-length: %w", err) } // Go's client defaults to chunked encoding after a 200ms delay if the following cases are true: // * the request body blocks // * the content length is not set (or set to -1) // * the method doesn't usually have a body (GET, HEAD, DELETE, ...) // * there is no transfer-encoding=chunked already set. // So, if transfer cannot be chunked and content length is 0, we dont set a request body. if !isWebsocket && !isTransferEncodingChunked(req) && req.ContentLength == 0 { req.Body = http.NoBody } stripWebsocketUpgradeHeader(req) // Check for tracing on request tracedReq := tracing.NewTracedHTTPRequest(req, connIndex, log) return tracedReq, err } func setContentLength(req *http.Request) error { var err error if contentLengthStr := req.Header.Get("Content-Length"); contentLengthStr != "" { req.ContentLength, err = strconv.ParseInt(contentLengthStr, 10, 64) } return err } func isTransferEncodingChunked(req *http.Request) bool { transferEncodingVal := req.Header.Get("Transfer-Encoding") // https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Transfer-Encoding suggests that this can be a comma // separated value as well. return strings.Contains(strings.ToLower(transferEncodingVal), "chunked") } // A helper struct that guarantees a call to close only affects read side, but not write side. type nopCloserReadWriter struct { io.ReadWriteCloser // for use by Read only // we don't need a memory barrier here because there is an implicit assumption that // Read calls can't happen concurrently by different go-routines. sawEOF bool // should be updated and read using atomic primitives. // value is read in Read method and written in Close method, which could be done by different // go-routines. closed uint32 } func (np *nopCloserReadWriter) Read(p []byte) (n int, err error) { if np.sawEOF { return 0, io.EOF } if atomic.LoadUint32(&np.closed) > 0 { return 0, fmt.Errorf("closed by handler") } n, err = np.ReadWriteCloser.Read(p) if err == io.EOF { np.sawEOF = true } return } func (np *nopCloserReadWriter) Close() error { atomic.StoreUint32(&np.closed, 1) return nil } // muxerWrapper wraps DatagramMuxerV2 to satisfy the packet.FunnelUniPipe interface type muxerWrapper struct { muxer *quicpogs.DatagramMuxerV2 } func (rp *muxerWrapper) SendPacket(dst netip.Addr, pk packet.RawPacket) error { return rp.muxer.SendPacket(quicpogs.RawPacket(pk)) } func (rp *muxerWrapper) ReceivePacket(ctx context.Context) (packet.RawPacket, error) { pk, err := rp.muxer.ReceivePacket(ctx) if err != nil { return packet.RawPacket{}, err } rawPacket, ok := pk.(quicpogs.RawPacket) if ok { return packet.RawPacket(rawPacket), nil } return packet.RawPacket{}, fmt.Errorf("unexpected packet type %+v", pk) } func (rp *muxerWrapper) Close() error { return nil } func createUDPConnForConnIndex(connIndex uint8, localIP net.IP, logger *zerolog.Logger) (*net.UDPConn, error) { portMapMutex.Lock() defer portMapMutex.Unlock() if localIP == nil { localIP = net.IPv4zero } // if port was not set yet, it will be zero, so bind will randomly allocate one. if port, ok := portForConnIndex[connIndex]; ok { udpConn, err := net.ListenUDP("udp", &net.UDPAddr{IP: localIP, Port: port}) // if there wasn't an error, or if port was 0 (independently of error or not, just return) if err == nil { return udpConn, nil } else { logger.Debug().Err(err).Msgf("Unable to reuse port %d for connIndex %d. Falling back to random allocation.", port, connIndex) } } // if we reached here, then there was an error or port as not been allocated it. udpConn, err := net.ListenUDP("udp", &net.UDPAddr{IP: localIP, Port: 0}) if err == nil { udpAddr, ok := (udpConn.LocalAddr()).(*net.UDPAddr) if !ok { return nil, fmt.Errorf("unable to cast to udpConn") } portForConnIndex[connIndex] = udpAddr.Port } else { delete(portForConnIndex, connIndex) } return udpConn, err } type wrapCloseableConnQuicConnection struct { quic.Connection udpConn *net.UDPConn } func (w *wrapCloseableConnQuicConnection) CloseWithError(errorCode quic.ApplicationErrorCode, reason string) error { err := w.Connection.CloseWithError(errorCode, reason) w.udpConn.Close() return err }