Add VNC console proxy

Running request-console with the `-l` flag spawns a proxy (by default
on localhost:5900) to connect to with a VNC client.

cli/server_request_console.go

@@ -2,8 +2,11 @@ package cli
 
 import (
 	"fmt"
+	"io"
+	"net"
 
 	"github.com/spf13/cobra"
+	"golang.org/x/net/websocket"
 )
 
 func newServerRequestConsoleCommand(cli *CLI) *cobra.Command {
@@ -16,9 +19,55 @@ func newServerRequestConsoleCommand(cli *CLI) *cobra.Command {
 		PreRunE:               cli.ensureToken,
 		RunE:                  cli.wrap(runServerRequestConsole),
 	}
+	cmd.Flags().BoolP("listen", "l", false, "Listen for a VNC client")
+	cmd.Flags().StringP("bind", "b", "localhost:5900", "Bind host/port for VNC port")
 	return cmd
 }
 
+func consoleProxy(bind, url string) error {
+	s, err := net.Listen("tcp", bind)
+	if err != nil {
+		return err
+	}
+	defer s.Close()
+
+	fmt.Printf("\nListening for VNC client on %v...\n", bind)
+
+	conn, err := s.Accept()
+	if err != nil {
+		return err
+	}
+	fmt.Printf("VNC Client connect, establishing WebSocket connection...\n")
+	defer conn.Close()
+
+	ws, err := websocket.Dial(url, "binary", "https://console.hetzner.cloud/")
+	if err != nil {
+		return err
+	}
+	ws.PayloadType = websocket.BinaryFrame
+	fmt.Printf("Connected!\n")
+	defer ws.Close()
+
+	in := make(chan error, 1)
+	go func() {
+		_, err := io.Copy(conn, ws)
+		in <- err
+	}()
+
+	out := make(chan error, 1)
+	go func() {
+		_, err := io.Copy(ws, conn)
+		out <- err
+	}()
+
+	select {
+	case err = <-in:
+		return err
+	case err = <-out:
+		return err
+	}
+}
+
 func runServerRequestConsole(cli *CLI, cmd *cobra.Command, args []string) error {
 	idOrName := args[0]
 	server, _, err := cli.Client().Server.Get(cli.Context, idOrName)
@@ -41,5 +90,20 @@ func runServerRequestConsole(cli *CLI, cmd *cobra.Command, args []string) error
 	fmt.Printf("Console for server %d:\n", server.ID)
 	fmt.Printf("WebSocket URL: %s\n", result.WSSURL)
 	fmt.Printf("VNC Password: %s\n", result.Password)
+
+	listen, err := cmd.Flags().GetBool("listen")
+	if err != nil {
+		return err
+	}
+
+	if listen {
+		bind, err := cmd.Flags().GetString("bind")
+		if err != nil {
+			return err
+		}
+
+		return consoleProxy(bind, result.WSSURL)
+	}
+
 	return nil
 }

go.mod

@@ -9,6 +9,7 @@ require (
 	github.com/spf13/cobra v0.0.7
 	github.com/spf13/pflag v1.0.5
 	golang.org/x/crypto v0.0.0-20200406173513-056763e48d71
+	golang.org/x/net v0.0.0-20190522155817-f3200d17e092
 )
 
 go 1.14

go.sum

@@ -130,6 +130,7 @@ golang.org/x/net v0.0.0-20181114220301-adae6a3d119a/go.mod h1:mL1N/T3taQHkDXs73r
 golang.org/x/net v0.0.0-20181220203305-927f97764cc3/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20190311183353-d8887717615a/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
 golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
+golang.org/x/net v0.0.0-20190522155817-f3200d17e092 h1:4QSRKanuywn15aTZvI/mIDEgPQpswuFndXpOj3rKEco=
 golang.org/x/net v0.0.0-20190522155817-f3200d17e092/go.mod h1:HSz+uSET+XFnRR8LxR5pz3Of3rY3CfYBVs4xY44aLks=
 golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
 golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=