AUTH-1070: added SSH/protocol forwarding

carrier/carrier.go

@@ -0,0 +1,131 @@
+//Package carrier provides a WebSocket proxy to carry or proxy a connection
+//from the local client to the edge. See it as a wrapper around any protocol
+//that it packages up in a WebSocket connection to the edge.
+package carrier
+
+import (
+	"errors"
+	"io"
+	"net"
+	"net/http"
+	"os"
+	"strings"
+
+	"github.com/cloudflare/cloudflared/cmd/cloudflared/access"
+	"github.com/cloudflare/cloudflared/websocket"
+	"github.com/sirupsen/logrus"
+)
+
+// StdinoutStream is empty struct for wrapping stdin/stdout
+// into a single ReadWriter
+type StdinoutStream struct {
+}
+
+// Read will read from Stdin
+func (c *StdinoutStream) Read(p []byte) (int, error) {
+	return os.Stdin.Read(p)
+
+}
+
+// Write will write to Stdout
+func (c *StdinoutStream) Write(p []byte) (int, error) {
+	return os.Stdout.Write(p)
+}
+
+// StartClient will copy the data from stdin/stdout over a WebSocket connection
+// to the edge (originURL)
+func StartClient(logger *logrus.Logger, originURL string, stream io.ReadWriter) error {
+	return serveStream(logger, originURL, stream)
+}
+
+// StartServer will setup a server on a specified port and copy data over a WebSocket connection
+// to the edge (originURL)
+func StartServer(logger *logrus.Logger, address, originURL string, shutdownC <-chan struct{}) error {
+	listener, err := net.Listen("tcp", address)
+	if err != nil {
+		logger.WithError(err).Error("failed to start forwarding server")
+		return err
+	}
+	defer listener.Close()
+	for {
+		select {
+		case <-shutdownC:
+			return nil
+		default:
+			conn, err := listener.Accept()
+			if err != nil {
+				return err
+			}
+			go serveConnection(logger, conn, originURL)
+		}
+	}
+}
+
+// serveConnection handles connections for the StartServer call
+func serveConnection(logger *logrus.Logger, c net.Conn, originURL string) {
+	defer c.Close()
+	serveStream(logger, originURL, c)
+}
+
+// serveStream will serve the data over the WebSocket stream
+func serveStream(logger *logrus.Logger, originURL string, conn io.ReadWriter) error {
+	wsConn, err := createWebsocketStream(originURL)
+	if err != nil {
+		logger.WithError(err).Error("failed to create websocket stream")
+		return err
+	}
+	defer wsConn.Close()
+
+	websocket.Stream(wsConn, conn)
+
+	return nil
+}
+
+// createWebsocketStream will create a WebSocket connection to stream data over
+// It also handles redirects from Access and will present that flow if
+// the token is not present on the request
+func createWebsocketStream(originURL string) (*websocket.Conn, error) {
+	req, err := http.NewRequest(http.MethodGet, originURL, nil)
+	if err != nil {
+		return nil, err
+	}
+	wsConn, resp, err := websocket.ClientConnect(req, nil)
+	if err != nil && resp != nil && resp.StatusCode > 300 {
+		location, err := resp.Location()
+		if err != nil {
+			return nil, err
+		}
+		if !strings.Contains(location.String(), "cdn-cgi/access/login") {
+			return nil, errors.New("not an Access redirect")
+		}
+		req, err := buildAccessRequest(originURL)
+		if err != nil {
+			return nil, err
+		}
+
+		wsConn, _, err = websocket.ClientConnect(req, nil)
+		if err != nil {
+			return nil, err
+		}
+	} else if err != nil {
+		return nil, err
+	}
+
+	return &websocket.Conn{Conn: wsConn}, nil
+}
+
+// buildAccessRequest builds an HTTP request with the Access token set
+func buildAccessRequest(originURL string) (*http.Request, error) {
+	req, err := http.NewRequest(http.MethodGet, originURL, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	token, err := access.FetchToken(req.URL)
+	if err != nil {
+		return nil, err
+	}
+	req.Header.Set("cf-access-token", token)
+
+	return req, nil
+}