package connection import ( "context" "crypto/tls" "fmt" "io" "net" "net/http" "strconv" "strings" "time" "github.com/google/uuid" "github.com/lucas-clemente/quic-go" "github.com/pkg/errors" "github.com/rs/zerolog" "golang.org/x/sync/errgroup" "github.com/cloudflare/cloudflared/datagramsession" "github.com/cloudflare/cloudflared/ingress" quicpogs "github.com/cloudflare/cloudflared/quic" 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" ) // QUICConnection represents the type that facilitates Proxying via QUIC streams. type QUICConnection struct { session quic.Session logger *zerolog.Logger httpProxy OriginProxy sessionManager datagramsession.Manager controlStreamHandler ControlStreamHandler } // NewQUICConnection returns a new instance of QUICConnection. func NewQUICConnection( ctx context.Context, quicConfig *quic.Config, edgeAddr net.Addr, tlsConfig *tls.Config, httpProxy OriginProxy, connOptions *tunnelpogs.ConnectionOptions, controlStreamHandler ControlStreamHandler, logger *zerolog.Logger, ) (*QUICConnection, error) { session, err := quic.DialAddr(edgeAddr.String(), tlsConfig, quicConfig) if err != nil { return nil, fmt.Errorf("failed to dial to edge: %w", err) } registrationStream, err := session.OpenStream() if err != nil { return nil, fmt.Errorf("failed to open a registration stream: %w", err) } err = controlStreamHandler.ServeControlStream(ctx, registrationStream, connOptions, false) if err != nil { // Not wrapping error here to be consistent with the http2 message. return nil, err } datagramMuxer, err := quicpogs.NewDatagramMuxer(session) if err != nil { return nil, err } sessionManager := datagramsession.NewManager(datagramMuxer, logger) return &QUICConnection{ session: session, httpProxy: httpProxy, logger: logger, sessionManager: sessionManager, controlStreamHandler: controlStreamHandler, }, nil } // Serve starts a QUIC session that begins accepting streams. func (q *QUICConnection) Serve(ctx context.Context) error { // 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) errGroup.Go(func() error { defer cancel() return q.acceptStream(ctx) }) errGroup.Go(func() error { defer cancel() return q.sessionManager.Serve(ctx) }) return errGroup.Wait() } func (q *QUICConnection) acceptStream(ctx context.Context) error { defer q.Close() for { stream, 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 func() { defer stream.Close() if err = q.handleStream(stream); err != nil { q.logger.Err(err).Msg("Failed to handle QUIC stream") } }() } } // Close closes the session with no errors specified. func (q *QUICConnection) Close() { q.session.CloseWithError(0, "") } func (q *QUICConnection) handleStream(stream quic.Stream) 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 nil } return q.handleDataStream(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(stream *quicpogs.RequestServerStream) error { connectRequest, err := stream.ReadConnectRequestData() if err != nil { return err } switch connectRequest.Type { case quicpogs.ConnectionTypeHTTP, quicpogs.ConnectionTypeWebsocket: req, err := buildHTTPRequest(connectRequest, stream) if err != nil { return err } w := newHTTPResponseAdapter(stream) return q.httpProxy.ProxyHTTP(w, req, connectRequest.Type == quicpogs.ConnectionTypeWebsocket) case quicpogs.ConnectionTypeTCP: rwa := &streamReadWriteAcker{stream} return q.httpProxy.ProxyTCP(context.Background(), rwa, &TCPRequest{Dest: connectRequest.Dest}) } return nil } func (q *QUICConnection) handleRPCStream(rpcStream *quicpogs.RPCServerStream) error { return rpcStream.Serve(q, q.logger) } // 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) error { // 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 { q.logger.Err(err).Msgf("Failed to create udp proxy to %s:%d", dstIP, dstPort) return err } session, err := q.sessionManager.RegisterSession(ctx, sessionID, originProxy) if err != nil { q.logger.Err(err).Str("sessionID", sessionID.String()).Msgf("Failed to register udp session") return err } go q.serveUDPSession(session, closeAfterIdleHint) q.logger.Debug().Msgf("Registered session %v, %v, %v", sessionID, dstIP, dstPort) return 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).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) stream, 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).Str("sessionID", sessionID.String()). Msgf("Failed to open quic stream to unregister udp session with edge") return } rpcClientStream, err := quicpogs.NewRPCClientStream(ctx, stream, 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 } 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) } // streamReadWriteAcker is a light wrapper over QUIC streams with a callback to send response back to // the client. type streamReadWriteAcker struct { *quicpogs.RequestServerStream } // AckConnection acks response back to the proxy. func (s *streamReadWriteAcker) AckConnection() error { return s.WriteConnectResponseData(nil) } // httpResponseAdapter translates responses written by the HTTP Proxy into ones that can be used in QUIC. type httpResponseAdapter struct { *quicpogs.RequestServerStream } func newHTTPResponseAdapter(s *quicpogs.RequestServerStream) httpResponseAdapter { return httpResponseAdapter{s} } 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) WriteErrorResponse(err error) { hrw.WriteConnectResponseData(err, quicpogs.Metadata{Key: "HttpStatus", Val: strconv.Itoa(http.StatusBadGateway)}) } func buildHTTPRequest(connectRequest *quicpogs.ConnectRequest, body io.ReadCloser) (*http.Request, error) { metadata := connectRequest.MetadataMap() dest := connectRequest.Dest method := metadata[HTTPMethodKey] host := metadata[HTTPHostKey] isWebsocket := connectRequest.Type == quicpogs.ConnectionTypeWebsocket req, err := http.NewRequest(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 = nil } stripWebsocketUpgradeHeader(req) return req, 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") }