cloudflared-mirror/carrier/websocket.go

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package carrier
import (
"io"
"net/http"
"net/http/httputil"
"net/url"
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"github.com/gorilla/websocket"
"github.com/rs/zerolog"
"github.com/cloudflare/cloudflared/token"
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cfwebsocket "github.com/cloudflare/cloudflared/websocket"
)
// Websocket is used to carry data via WS binary frames over the tunnel from client to the origin
// This implements the functions for glider proxy (sock5) and the carrier interface
type Websocket struct {
log *zerolog.Logger
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isSocks bool
}
// NewWSConnection returns a new connection object
func NewWSConnection(log *zerolog.Logger) Connection {
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return &Websocket{
log: log,
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}
}
// ServeStream will create a Websocket client stream connection to the edge
// it blocks and writes the raw data from conn over the tunnel
func (ws *Websocket) ServeStream(options *StartOptions, conn io.ReadWriter) error {
wsConn, err := createWebsocketStream(options, ws.log)
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if err != nil {
ws.log.Err(err).Str(LogFieldOriginURL, options.OriginURL).Msg("failed to connect to origin")
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return err
}
defer wsConn.Close()
cfwebsocket.Stream(wsConn, conn, ws.log)
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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(options *StartOptions, log *zerolog.Logger) (*cfwebsocket.GorillaConn, error) {
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req, err := http.NewRequest(http.MethodGet, options.OriginURL, nil)
if err != nil {
return nil, err
}
req.Header = options.Headers
if options.Host != "" {
req.Host = options.Host
}
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dump, err := httputil.DumpRequest(req, false)
log.Debug().Msgf("Websocket request: %s", string(dump))
dialer := &websocket.Dialer{
TLSClientConfig: options.TLSClientConfig,
Proxy: http.ProxyFromEnvironment,
}
wsConn, resp, err := clientConnect(req, dialer)
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defer closeRespBody(resp)
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if err != nil && IsAccessResponse(resp) {
// Only get Access app info if we know the origin is protected by Access
originReq, err := http.NewRequest(http.MethodGet, options.OriginURL, nil)
if err != nil {
return nil, err
}
appInfo, err := token.GetAppInfo(originReq.URL)
if err != nil {
return nil, err
}
options.AppInfo = appInfo
wsConn, err = createAccessAuthenticatedStream(options, log)
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if err != nil {
return nil, err
}
} else if err != nil {
return nil, err
}
return &cfwebsocket.GorillaConn{Conn: wsConn}, nil
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}
var stripWebsocketHeaders = []string{
"Upgrade",
"Connection",
"Sec-Websocket-Key",
"Sec-Websocket-Version",
"Sec-Websocket-Extensions",
}
// the gorilla websocket library sets its own Upgrade, Connection, Sec-WebSocket-Key,
// Sec-WebSocket-Version and Sec-Websocket-Extensions headers.
// https://github.com/gorilla/websocket/blob/master/client.go#L189-L194.
func websocketHeaders(req *http.Request) http.Header {
wsHeaders := make(http.Header)
for key, val := range req.Header {
wsHeaders[key] = val
}
// Assume the header keys are in canonical format.
for _, header := range stripWebsocketHeaders {
wsHeaders.Del(header)
}
wsHeaders.Set("Host", req.Host) // See TUN-1097
return wsHeaders
}
// clientConnect creates a WebSocket client connection for provided request. Caller is responsible for closing
// the connection. The response body may not contain the entire response and does
// not need to be closed by the application.
func clientConnect(req *http.Request, dialler *websocket.Dialer) (*websocket.Conn, *http.Response, error) {
req.URL.Scheme = changeRequestScheme(req.URL)
wsHeaders := websocketHeaders(req)
if dialler == nil {
dialler = &websocket.Dialer{
Proxy: http.ProxyFromEnvironment,
}
}
conn, response, err := dialler.Dial(req.URL.String(), wsHeaders)
if err != nil {
return nil, response, err
}
return conn, response, nil
}
// changeRequestScheme is needed as the gorilla websocket library requires the ws scheme.
// (even though it changes it back to http/https, but ¯\_(ツ)_/¯.)
func changeRequestScheme(reqURL *url.URL) string {
switch reqURL.Scheme {
case "https":
return "wss"
case "http":
return "ws"
case "":
return "ws"
default:
return reqURL.Scheme
}
}
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// createAccessAuthenticatedStream will try load a token from storage and make
// a connection with the token set on the request. If it still get redirect,
// this probably means the token in storage is invalid (expired/revoked). If that
// happens it deletes the token and runs the connection again, so the user can
// login again and generate a new one.
func createAccessAuthenticatedStream(options *StartOptions, log *zerolog.Logger) (*websocket.Conn, error) {
wsConn, resp, err := createAccessWebSocketStream(options, log)
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defer closeRespBody(resp)
if err == nil {
return wsConn, nil
}
if !IsAccessResponse(resp) {
return nil, err
}
// Access Token is invalid for some reason. Go through regen flow
if err := token.RemoveTokenIfExists(options.AppInfo); err != nil {
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return nil, err
}
wsConn, resp, err = createAccessWebSocketStream(options, log)
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defer closeRespBody(resp)
if err != nil {
return nil, err
}
return wsConn, nil
}
// createAccessWebSocketStream builds an Access request and makes a connection
func createAccessWebSocketStream(options *StartOptions, log *zerolog.Logger) (*websocket.Conn, *http.Response, error) {
req, err := BuildAccessRequest(options, log)
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if err != nil {
return nil, nil, err
}
dump, err := httputil.DumpRequest(req, false)
log.Debug().Msgf("Access Websocket request: %s", string(dump))
conn, resp, err := clientConnect(req, nil)
if resp != nil {
r, err := httputil.DumpResponse(resp, true)
if r != nil {
log.Debug().Msgf("Websocket response: %q", r)
} else if err != nil {
log.Debug().Msgf("Websocket response error: %v", err)
}
}
return conn, resp, err
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}