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