154 lines
4.2 KiB
Go
154 lines
4.2 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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"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/pkg/errors"
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)
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type StartOptions struct {
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OriginURL string
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Headers http.Header
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}
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// Connection wraps up all the needed functions to forward over the tunnel
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type Connection interface {
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// ServeStream is used to forward data from the client to the edge
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ServeStream(*StartOptions, io.ReadWriter) error
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// StartServer is used to listen for incoming connections from the edge to the origin
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StartServer(net.Listener, string, <-chan struct{}) error
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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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// Helper to allow defering the response close with a check that the resp is not nil
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func closeRespBody(resp *http.Response) {
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if resp != nil {
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resp.Body.Close()
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}
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}
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// StartForwarder will setup a listener on a specified address/port and then
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// forward connections to the origin by calling `Serve()`.
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func StartForwarder(conn Connection, address string, shutdownC <-chan struct{}, options *StartOptions) error {
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listener, err := net.Listen("tcp", address)
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if err != nil {
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return errors.Wrap(err, "failed to start forwarding server")
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}
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return Serve(conn, listener, shutdownC, options)
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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(conn Connection, stream io.ReadWriter, options *StartOptions) error {
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return serveStream(conn, stream, options)
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}
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// Serve accepts incoming connections on the specified net.Listener.
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// Each connection is handled in a new goroutine: its data is copied over a
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// WebSocket connection to the edge (originURL).
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// `Serve` always closes `listener`.
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func Serve(remoteConn Connection, listener net.Listener, shutdownC <-chan struct{}, options *StartOptions) error {
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defer listener.Close()
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errChan := make(chan error)
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go func() {
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for {
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conn, err := listener.Accept()
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if err != nil {
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errChan <- err
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return
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}
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go serveConnection(remoteConn, conn, options)
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}
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}()
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select {
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case <-shutdownC:
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return nil
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case err := <-errChan:
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return err
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}
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}
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// serveConnection handles connections for the Serve() call
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func serveConnection(remoteConn Connection, c net.Conn, options *StartOptions) {
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defer c.Close()
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serveStream(remoteConn, c, options)
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}
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// serveStream will serve the data over the WebSocket stream
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func serveStream(remoteConn Connection, conn io.ReadWriter, options *StartOptions) error {
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return remoteConn.ServeStream(options, conn)
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}
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// IsAccessResponse checks the http Response to see if the url location
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// contains the Access structure.
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func IsAccessResponse(resp *http.Response) bool {
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if resp == nil || resp.StatusCode != http.StatusFound {
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return false
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}
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location, err := resp.Location()
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if err != nil || location == nil {
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return false
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}
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if strings.HasPrefix(location.Path, "/cdn-cgi/access/login") {
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return true
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}
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return false
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}
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// BuildAccessRequest builds an HTTP request with the Access token set
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func BuildAccessRequest(options *StartOptions) (*http.Request, error) {
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req, err := http.NewRequest(http.MethodGet, options.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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// We need to create a new request as FetchToken will modify req (boo mutable)
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// as it has to follow redirect on the API and such, so here we init a new one
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originRequest, err := http.NewRequest(http.MethodGet, options.OriginURL, nil)
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if err != nil {
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return nil, err
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}
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originRequest.Header.Set("cf-access-token", token)
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for k, v := range options.Headers {
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if len(v) >= 1 {
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originRequest.Header.Set(k, v[0])
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}
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}
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return originRequest, nil
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}
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