Function DirectTCPIPHandler

tcpip.go:28–66

DirectTCPIPHandler can be enabled by adding it to the server's ChannelHandlers under direct-tcpip.

(srv *Server, conn *gossh.ServerConn, newChan gossh.NewChannel, ctx Context)

// DirectTCPIPHandler can be enabled by adding it to the server's
// ChannelHandlers under direct-tcpip.
func DirectTCPIPHandler(srv *Server, conn *gossh.ServerConn, newChan gossh.NewChannel, ctx Context) {
	d := localForwardChannelData{}
	if err := gossh.Unmarshal(newChan.ExtraData(), &d); err != nil {
		newChan.Reject(gossh.ConnectionFailed, "error parsing forward data: "+err.Error())
		return
	}

	if srv.LocalPortForwardingCallback == nil || !srv.LocalPortForwardingCallback(ctx, d.DestAddr, d.DestPort) {
		newChan.Reject(gossh.Prohibited, "port forwarding is disabled")
		return
	}

	dest := net.JoinHostPort(d.DestAddr, strconv.FormatInt(int64(d.DestPort), 10))

	var dialer net.Dialer
	dconn, err := dialer.DialContext(ctx, "tcp", dest)
	if err != nil {
		newChan.Reject(gossh.ConnectionFailed, err.Error())
		return
	}

	ch, reqs, err := newChan.Accept()
	if err != nil {
		dconn.Close()
		return
	}
	go gossh.DiscardRequests(reqs)

	go func() {
		defer ch.Close()
		defer dconn.Close()
		io.Copy(ch, dconn)
	}()
	go func() {
		defer ch.Close()
		defer dconn.Close()
		io.Copy(dconn, ch)
	}()
}

type remoteForwardRequest struct {
	BindAddr string