mirror of
https://github.com/bolkedebruin/rdpgw.git
synced 2025-07-21 10:06:01 +02:00
More refactor
This commit is contained in:
Bolke de Bruin
parent
33290f59e6
commit
e9b7b352cf
5 changed files with 180 additions and 570 deletions
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@ -1,5 +1,7 @@
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package main
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package main
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import "github.com/bolkedebruin/rdpgw/protocol"
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// RejectOption represents an option used to control the way connection is
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// RejectOption represents an option used to control the way connection is
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// rejected.
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// rejected.
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type RejectOption func(*rejectConnectionError)
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type RejectOption func(*rejectConnectionError)
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@ -22,7 +24,7 @@ func RejectionStatus(code int) RejectOption {
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// RejectionHeader returns an option that makes connection to be rejected with
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// RejectionHeader returns an option that makes connection to be rejected with
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// given HTTP headers.
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// given HTTP headers.
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func RejectionHeader(h HandshakeHeader) RejectOption {
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func RejectionHeader(h protocol.HandshakeHeader) RejectOption {
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return func(err *rejectConnectionError) {
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return func(err *rejectConnectionError) {
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err.header = h
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err.header = h
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}
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}
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@ -44,7 +46,7 @@ func RejectConnectionError(options ...RejectOption) error {
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type rejectConnectionError struct {
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type rejectConnectionError struct {
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reason string
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reason string
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code int
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code int
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header HandshakeHeader
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header protocol.HandshakeHeader
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}
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}
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// Error implements error interface.
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// Error implements error interface.
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8
main.go
8
main.go
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@ -4,9 +4,9 @@ import (
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"context"
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"context"
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"crypto/tls"
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"crypto/tls"
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"github.com/bolkedebruin/rdpgw/config"
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"github.com/bolkedebruin/rdpgw/config"
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"github.com/bolkedebruin/rdpgw/protocol"
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"github.com/coreos/go-oidc/v3/oidc"
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"github.com/coreos/go-oidc/v3/oidc"
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"github.com/patrickmn/go-cache"
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"github.com/patrickmn/go-cache"
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"github.com/prometheus/client_golang/prometheus"
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"github.com/prometheus/client_golang/prometheus/promhttp"
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"github.com/prometheus/client_golang/prometheus/promhttp"
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"github.com/spf13/cobra"
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"github.com/spf13/cobra"
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"golang.org/x/oauth2"
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"golang.org/x/oauth2"
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@ -89,15 +89,11 @@ func main() {
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TLSNextProto: make(map[string]func(*http.Server, *tls.Conn, http.Handler)), // disable http2
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TLSNextProto: make(map[string]func(*http.Server, *tls.Conn, http.Handler)), // disable http2
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}
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}
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http.HandleFunc("/remoteDesktopGateway/", handleGatewayProtocol)
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http.HandleFunc("/remoteDesktopGateway/", protocol.HandleGatewayProtocol)
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http.HandleFunc("/connect", handleRdpDownload)
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http.HandleFunc("/connect", handleRdpDownload)
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http.Handle("/metrics", promhttp.Handler())
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http.Handle("/metrics", promhttp.Handler())
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http.HandleFunc("/callback", handleCallback)
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http.HandleFunc("/callback", handleCallback)
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prometheus.MustRegister(connectionCache)
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prometheus.MustRegister(legacyConnections)
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prometheus.MustRegister(websocketConnections)
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err = server.ListenAndServeTLS("", "")
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err = server.ListenAndServeTLS("", "")
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if err != nil {
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if err != nil {
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log.Fatal("ListenAndServe: ", err)
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log.Fatal("ListenAndServe: ", err)
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@ -20,19 +20,21 @@ type VerifyTunnelAuthFunc func(string) (bool, error)
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type VerifyServerFunc func(string) (bool, error)
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type VerifyServerFunc func(string) (bool, error)
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type Handler struct {
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type Handler struct {
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Transport transport.Transport
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TransportIn transport.Transport
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TransportOut transport.Transport
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VerifyPAACookieFunc VerifyPAACookieFunc
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VerifyPAACookieFunc VerifyPAACookieFunc
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VerifyTunnelAuthFunc VerifyTunnelAuthFunc
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VerifyTunnelAuthFunc VerifyTunnelAuthFunc
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VerifyServerFunc VerifyServerFunc
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VerifyServerFunc VerifyServerFunc
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SmartCardAuth bool
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SmartCardAuth bool
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TokenAuth bool
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TokenAuth bool
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ClientName string
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ClientName string
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Remote net.Conn
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Remote net.Conn
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}
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}
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func NewHandler(t transport.Transport) *Handler {
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func NewHandler(in transport.Transport, out transport.Transport) *Handler {
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h := &Handler{
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h := &Handler{
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Transport: t,
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TransportIn: in,
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TransportOut: out,
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}
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}
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return h
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return h
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}
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}
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@ -49,8 +51,9 @@ func (h *Handler) Process() error {
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case PKT_TYPE_HANDSHAKE_REQUEST:
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case PKT_TYPE_HANDSHAKE_REQUEST:
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major, minor, _, auth := readHandshake(pkt)
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major, minor, _, auth := readHandshake(pkt)
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msg := h.handshakeResponse(major, minor, auth)
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msg := h.handshakeResponse(major, minor, auth)
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h.Transport.WritePacket(msg)
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h.TransportOut.WritePacket(msg)
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case PKT_TYPE_TUNNEL_CREATE:
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case PKT_TYPE_TUNNEL_CREATE:
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log.Printf("Tunnel create")
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_, cookie := readCreateTunnelRequest(pkt)
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_, cookie := readCreateTunnelRequest(pkt)
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if h.VerifyPAACookieFunc != nil {
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if h.VerifyPAACookieFunc != nil {
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if ok, _ := h.VerifyPAACookieFunc(cookie); ok == false {
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if ok, _ := h.VerifyPAACookieFunc(cookie); ok == false {
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@ -59,11 +62,13 @@ func (h *Handler) Process() error {
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}
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}
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}
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}
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msg := createTunnelResponse()
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msg := createTunnelResponse()
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h.Transport.WritePacket(msg)
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h.TransportOut.WritePacket(msg)
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log.Printf("Tunnel done")
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case PKT_TYPE_TUNNEL_AUTH:
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case PKT_TYPE_TUNNEL_AUTH:
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log.Printf("Tunnel auth")
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h.readTunnelAuthRequest(pkt)
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h.readTunnelAuthRequest(pkt)
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msg := h.createTunnelAuthResponse()
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msg := h.createTunnelAuthResponse()
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h.Transport.WritePacket(msg)
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h.TransportOut.WritePacket(msg)
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case PKT_TYPE_CHANNEL_CREATE:
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case PKT_TYPE_CHANNEL_CREATE:
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server, port := readChannelCreateRequest(pkt)
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server, port := readChannelCreateRequest(pkt)
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log.Printf("Establishing connection to RDP server: %s on port %d (%x)", server, port, server)
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log.Printf("Establishing connection to RDP server: %s on port %d (%x)", server, port, server)
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@ -77,7 +82,7 @@ func (h *Handler) Process() error {
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}
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}
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log.Printf("Connection established")
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log.Printf("Connection established")
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msg := createChannelCreateResponse()
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msg := createChannelCreateResponse()
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h.Transport.WritePacket(msg)
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h.TransportOut.WritePacket(msg)
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// Make sure to start the flow from the RDP server first otherwise connections
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// Make sure to start the flow from the RDP server first otherwise connections
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// might hang eventually
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// might hang eventually
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@ -86,9 +91,10 @@ func (h *Handler) Process() error {
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h.forwardDataPacket(pkt)
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h.forwardDataPacket(pkt)
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case PKT_TYPE_KEEPALIVE:
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case PKT_TYPE_KEEPALIVE:
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// avoid concurrency issues
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// avoid concurrency issues
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// p.Transport.Write(createPacket(PKT_TYPE_KEEPALIVE, []byte{}))
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// p.TransportIn.Write(createPacket(PKT_TYPE_KEEPALIVE, []byte{}))
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case PKT_TYPE_CLOSE_CHANNEL:
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case PKT_TYPE_CLOSE_CHANNEL:
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h.Transport.Close()
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h.TransportIn.Close()
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h.TransportOut.Close()
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default:
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default:
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log.Printf("Unknown packet (size %d): %x", sz, pkt)
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log.Printf("Unknown packet (size %d): %x", sz, pkt)
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}
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}
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@ -101,7 +107,7 @@ func (h *Handler) ReadMessage() (pt int, n int, msg []byte, err error) {
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buf := make([]byte, 4096)
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buf := make([]byte, 4096)
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for {
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for {
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size, pkt, err := h.Transport.ReadPacket()
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size, pkt, err := h.TransportIn.ReadPacket()
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if err != nil {
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if err != nil {
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return 0, 0, []byte{0, 0}, err
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return 0, 0, []byte{0, 0}, err
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}
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}
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@ -337,7 +343,7 @@ func (h *Handler) sendDataPacket() {
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break
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break
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}
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}
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b1.Write(buf[:n])
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b1.Write(buf[:n])
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h.Transport.WritePacket(createPacket(PKT_TYPE_DATA, b1.Bytes()))
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h.TransportOut.WritePacket(createPacket(PKT_TYPE_DATA, b1.Bytes()))
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b1.Reset()
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b1.Reset()
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}
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}
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}
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}
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156
protocol/rdg.go
Normal file
156
protocol/rdg.go
Normal file
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@ -0,0 +1,156 @@
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package protocol
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import (
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"github.com/bolkedebruin/rdpgw/transport"
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"github.com/gorilla/websocket"
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"github.com/patrickmn/go-cache"
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"github.com/prometheus/client_golang/prometheus"
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"io"
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"log"
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"net"
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"net/http"
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"time"
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)
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const (
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rdgConnectionIdKey = "Rdg-Connection-Id"
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MethodRDGIN = "RDG_IN_DATA"
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MethodRDGOUT = "RDG_OUT_DATA"
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)
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var (
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connectionCache = prometheus.NewGauge(
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prometheus.GaugeOpts{
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Namespace: "rdpgw",
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Name: "connection_cache",
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Help: "The amount of connections in the cache",
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})
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websocketConnections = prometheus.NewGauge(
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prometheus.GaugeOpts{
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Namespace: "rdpgw",
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Name: "websocket_connections",
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Help: "The count of websocket connections",
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})
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legacyConnections = prometheus.NewGauge(
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prometheus.GaugeOpts{
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Namespace: "rdpgw",
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Name: "legacy_connections",
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Help: "The count of legacy https connections",
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})
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)
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// HandshakeHeader is the interface that writes both upgrade request or
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// response headers into a given io.Writer.
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type HandshakeHeader interface {
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io.WriterTo
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}
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type RdgSession struct {
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ConnId string
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CorrelationId string
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UserId string
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TransportIn transport.Transport
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TransportOut transport.Transport
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StateIn int
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StateOut int
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Remote net.Conn
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}
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var DefaultSession RdgSession
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var upgrader = websocket.Upgrader{}
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var c = cache.New(5*time.Minute, 10*time.Minute)
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func init() {
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prometheus.MustRegister(connectionCache)
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prometheus.MustRegister(legacyConnections)
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prometheus.MustRegister(websocketConnections)
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}
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func HandleGatewayProtocol(w http.ResponseWriter, r *http.Request) {
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connectionCache.Set(float64(c.ItemCount()))
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if r.Method == MethodRDGOUT {
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if r.Header.Get("Connection") != "upgrade" && r.Header.Get("Upgrade") != "websocket" {
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handleLegacyProtocol(w, r)
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return
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}
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r.Method = "GET" // force
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conn, err := upgrader.Upgrade(w, r, nil)
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if err != nil {
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log.Printf("Cannot upgrade falling back to old protocol: %s", err)
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return
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}
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defer conn.Close()
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handleWebsocketProtocol(conn)
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} else if r.Method == MethodRDGIN {
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handleLegacyProtocol(w, r)
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}
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}
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func handleWebsocketProtocol(c *websocket.Conn) {
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websocketConnections.Inc()
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defer websocketConnections.Dec()
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inout, _ := transport.NewWS(c)
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handler := NewHandler(inout, inout)
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handler.Process()
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}
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// The legacy protocol (no websockets) uses an RDG_IN_DATA for client -> server
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// and RDG_OUT_DATA for server -> client data. The handshake procedure is a bit different
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// to ensure the connections do not get cached or terminated by a proxy prematurely.
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func handleLegacyProtocol(w http.ResponseWriter, r *http.Request) {
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var s RdgSession
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connId := r.Header.Get(rdgConnectionIdKey)
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x, found := c.Get(connId)
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if !found {
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s = RdgSession{ConnId: connId, StateIn: 0, StateOut: 0}
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} else {
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s = x.(RdgSession)
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}
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log.Printf("Session %s, %t, %t", s.ConnId, s.TransportOut != nil, s.TransportIn != nil)
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if r.Method == MethodRDGOUT {
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out, err := transport.NewLegacy(w)
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if err != nil {
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log.Printf("cannot hijack connection to support RDG OUT data channel: %s", err)
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return
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}
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log.Printf("Opening RDGOUT for client %s", out.Conn.RemoteAddr().String())
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|
|
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|
s.TransportOut = out
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out.SendAccept(true)
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|
|
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c.Set(connId, s, cache.DefaultExpiration)
|
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|
} else if r.Method == MethodRDGIN {
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legacyConnections.Inc()
|
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|
defer legacyConnections.Dec()
|
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|
|
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|
in, err := transport.NewLegacy(w)
|
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|
if err != nil {
|
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|
log.Printf("cannot hijack connection to support RDG IN data channel: %s", err)
|
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|
return
|
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|
}
|
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|
defer in.Close()
|
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|
|
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|
if s.TransportIn == nil {
|
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|
s.TransportIn = in
|
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|
c.Set(connId, s, cache.DefaultExpiration)
|
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|
|
||||||
|
log.Printf("Opening RDGIN for client %s", in.Conn.RemoteAddr().String())
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in.SendAccept(false)
|
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|
|
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// read some initial data
|
||||||
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in.Drain()
|
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|
|
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|
log.Printf("Legacy handshake done for client %s", in.Conn.RemoteAddr().String())
|
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|
handler := NewHandler(in, s.TransportOut)
|
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|
handler.Process()
|
||||||
|
}
|
||||||
|
}
|
||||||
|
}
|
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550
rdg.go
550
rdg.go
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|
@ -1,550 +0,0 @@
|
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package main
|
|
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|
|
||||||
import (
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|
||||||
"bytes"
|
|
||||||
"encoding/binary"
|
|
||||||
"fmt"
|
|
||||||
"github.com/bolkedebruin/rdpgw/protocol"
|
|
||||||
"github.com/bolkedebruin/rdpgw/transport"
|
|
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"github.com/gorilla/websocket"
|
|
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"github.com/patrickmn/go-cache"
|
|
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"github.com/prometheus/client_golang/prometheus"
|
|
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"io"
|
|
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"log"
|
|
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"net"
|
|
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"net/http"
|
|
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"strconv"
|
|
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"time"
|
|
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"unicode/utf16"
|
|
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"unicode/utf8"
|
|
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)
|
|
||||||
|
|
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const (
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|
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crlf = "\r\n"
|
|
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rdgConnectionIdKey = "Rdg-Connection-Id"
|
|
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)
|
|
||||||
|
|
||||||
const (
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|
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PKT_TYPE_HANDSHAKE_REQUEST = 0x1
|
|
||||||
PKT_TYPE_HANDSHAKE_RESPONSE = 0x2
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|
||||||
PKT_TYPE_EXTENDED_AUTH_MSG = 0x3
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|
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PKT_TYPE_TUNNEL_CREATE = 0x4
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|
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PKT_TYPE_TUNNEL_RESPONSE = 0x5
|
|
||||||
PKT_TYPE_TUNNEL_AUTH = 0x6
|
|
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PKT_TYPE_TUNNEL_AUTH_RESPONSE = 0x7
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|
||||||
PKT_TYPE_CHANNEL_CREATE = 0x8
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|
||||||
PKT_TYPE_CHANNEL_RESPONSE = 0x9
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|
||||||
PKT_TYPE_DATA = 0xA
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|
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PKT_TYPE_SERVICE_MESSAGE = 0xB
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|
||||||
PKT_TYPE_REAUTH_MESSAGE = 0xC
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|
||||||
PKT_TYPE_KEEPALIVE = 0xD
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|
||||||
PKT_TYPE_CLOSE_CHANNEL = 0x10
|
|
||||||
PKT_TYPE_CLOSE_CHANNEL_RESPONSE = 0x11
|
|
||||||
)
|
|
||||||
|
|
||||||
const (
|
|
||||||
HTTP_TUNNEL_RESPONSE_FIELD_TUNNEL_ID = 0x01
|
|
||||||
HTTP_TUNNEL_RESPONSE_FIELD_CAPS = 0x02
|
|
||||||
HTTP_TUNNEL_RESPONSE_FIELD_SOH_REQ = 0x04
|
|
||||||
HTTP_TUNNEL_RESPONSE_FIELD_CONSENT_MSG = 0x10
|
|
||||||
)
|
|
||||||
|
|
||||||
const (
|
|
||||||
HTTP_EXTENDED_AUTH_NONE = 0x0
|
|
||||||
HTTP_EXTENDED_AUTH_SC = 0x1 /* Smart card authentication. */
|
|
||||||
HTTP_EXTENDED_AUTH_PAA = 0x02 /* Pluggable authentication. */
|
|
||||||
HTTP_EXTENDED_AUTH_SSPI_NTLM = 0x04 /* NTLM extended authentication. */
|
|
||||||
)
|
|
||||||
|
|
||||||
const (
|
|
||||||
HTTP_TUNNEL_AUTH_RESPONSE_FIELD_REDIR_FLAGS = 0x01
|
|
||||||
HTTP_TUNNEL_AUTH_RESPONSE_FIELD_IDLE_TIMEOUT = 0x02
|
|
||||||
HTTP_TUNNEL_AUTH_RESPONSE_FIELD_SOH_RESPONSE = 0x04
|
|
||||||
)
|
|
||||||
|
|
||||||
const (
|
|
||||||
HTTP_TUNNEL_REDIR_ENABLE_ALL = 0x80000000
|
|
||||||
HTTP_TUNNEL_REDIR_DISABLE_ALL = 0x40000000
|
|
||||||
HTTP_TUNNEL_REDIR_DISABLE_DRIVE = 0x01
|
|
||||||
HTTP_TUNNEL_REDIR_DISABLE_PRINTER = 0x02
|
|
||||||
HTTP_TUNNEL_REDIR_DISABLE_PORT = 0x03
|
|
||||||
HTTP_TUNNEL_REDIR_DISABLE_CLIPBOARD = 0x08
|
|
||||||
HTTP_TUNNEL_REDIR_DISABLE_PNP = 0x10
|
|
||||||
)
|
|
||||||
|
|
||||||
const (
|
|
||||||
HTTP_CHANNEL_RESPONSE_FIELD_CHANNELID = 0x01
|
|
||||||
HTTP_CHANNEL_RESPONSE_FIELD_AUTHNCOOKIE = 0x02
|
|
||||||
HTTP_CHANNEL_RESPONSE_FIELD_UDPPORT = 0x04
|
|
||||||
)
|
|
||||||
|
|
||||||
const (
|
|
||||||
HTTP_TUNNEL_PACKET_FIELD_PAA_COOKIE = 0x1
|
|
||||||
)
|
|
||||||
|
|
||||||
var (
|
|
||||||
connectionCache = prometheus.NewGauge(
|
|
||||||
prometheus.GaugeOpts{
|
|
||||||
Namespace: "rdpgw",
|
|
||||||
Name: "connection_cache",
|
|
||||||
Help: "The amount of connections in the cache",
|
|
||||||
})
|
|
||||||
|
|
||||||
websocketConnections = prometheus.NewGauge(
|
|
||||||
prometheus.GaugeOpts{
|
|
||||||
Namespace: "rdpgw",
|
|
||||||
Name: "websocket_connections",
|
|
||||||
Help: "The count of websocket connections",
|
|
||||||
})
|
|
||||||
|
|
||||||
legacyConnections = prometheus.NewGauge(
|
|
||||||
prometheus.GaugeOpts{
|
|
||||||
Namespace: "rdpgw",
|
|
||||||
Name: "legacy_connections",
|
|
||||||
Help: "The count of legacy https connections",
|
|
||||||
})
|
|
||||||
)
|
|
||||||
|
|
||||||
// HandshakeHeader is the interface that writes both upgrade request or
|
|
||||||
// response headers into a given io.Writer.
|
|
||||||
type HandshakeHeader interface {
|
|
||||||
io.WriterTo
|
|
||||||
}
|
|
||||||
|
|
||||||
type RdgSession struct {
|
|
||||||
ConnId string
|
|
||||||
CorrelationId string
|
|
||||||
UserId string
|
|
||||||
TransportIn transport.Transport
|
|
||||||
TransportOut transport.Transport
|
|
||||||
StateIn int
|
|
||||||
StateOut int
|
|
||||||
Remote net.Conn
|
|
||||||
}
|
|
||||||
|
|
||||||
// ErrNotHijacker is an error returned when http.ResponseWriter does not
|
|
||||||
// implement http.Hijacker interface.
|
|
||||||
var ErrNotHijacker = RejectConnectionError(
|
|
||||||
RejectionStatus(http.StatusInternalServerError),
|
|
||||||
RejectionReason("given http.ResponseWriter is not a http.Hijacker"),
|
|
||||||
)
|
|
||||||
|
|
||||||
var DefaultSession RdgSession
|
|
||||||
|
|
||||||
var upgrader = websocket.Upgrader{}
|
|
||||||
var c = cache.New(5*time.Minute, 10*time.Minute)
|
|
||||||
|
|
||||||
func handleGatewayProtocol(w http.ResponseWriter, r *http.Request) {
|
|
||||||
connectionCache.Set(float64(c.ItemCount()))
|
|
||||||
if r.Method == MethodRDGOUT {
|
|
||||||
if r.Header.Get("Connection") != "upgrade" && r.Header.Get("Upgrade") != "websocket" {
|
|
||||||
handleLegacyProtocol(w, r)
|
|
||||||
return
|
|
||||||
}
|
|
||||||
r.Method = "GET" // force
|
|
||||||
conn, err := upgrader.Upgrade(w, r, nil)
|
|
||||||
if err != nil {
|
|
||||||
log.Printf("Cannot upgrade falling back to old protocol: %s", err)
|
|
||||||
return
|
|
||||||
}
|
|
||||||
defer conn.Close()
|
|
||||||
|
|
||||||
handleWebsocketProtocol(conn)
|
|
||||||
} else if r.Method == MethodRDGIN {
|
|
||||||
handleLegacyProtocol(w, r)
|
|
||||||
}
|
|
||||||
}
|
|
||||||
|
|
||||||
func handleWebsocketProtocol(c *websocket.Conn) {
|
|
||||||
websocketConnections.Inc()
|
|
||||||
defer websocketConnections.Dec()
|
|
||||||
|
|
||||||
inout, _ := transport.NewWS(c)
|
|
||||||
handler := protocol.NewHandler(inout)
|
|
||||||
handler.Process()
|
|
||||||
}
|
|
||||||
|
|
||||||
// The legacy protocol (no websockets) uses an RDG_IN_DATA for client -> server
|
|
||||||
// and RDG_OUT_DATA for server -> client data. The handshake procedure is a bit different
|
|
||||||
// to ensure the connections do not get cached or terminated by a proxy prematurely.
|
|
||||||
func handleLegacyProtocol(w http.ResponseWriter, r *http.Request) {
|
|
||||||
var s RdgSession
|
|
||||||
|
|
||||||
connId := r.Header.Get(rdgConnectionIdKey)
|
|
||||||
x, found := c.Get(connId)
|
|
||||||
if !found {
|
|
||||||
log.Printf("No cached session found")
|
|
||||||
s = RdgSession{ConnId: connId, StateIn: 0, StateOut: 0}
|
|
||||||
} else {
|
|
||||||
log.Printf("Found cached session")
|
|
||||||
s = x.(RdgSession)
|
|
||||||
}
|
|
||||||
|
|
||||||
log.Printf("Session %s, %t, %t", s.ConnId, s.TransportOut != nil, s.TransportIn != nil)
|
|
||||||
|
|
||||||
if r.Method == MethodRDGOUT {
|
|
||||||
out, err := transport.NewLegacy(w)
|
|
||||||
if err != nil {
|
|
||||||
log.Printf("cannot hijack connection to support RDG OUT data channel: %s", err)
|
|
||||||
return
|
|
||||||
}
|
|
||||||
log.Printf("Opening RDGOUT for client %s", out.Conn.RemoteAddr().String())
|
|
||||||
|
|
||||||
s.TransportOut = out
|
|
||||||
out.SendAccept(true)
|
|
||||||
|
|
||||||
c.Set(connId, s, cache.DefaultExpiration)
|
|
||||||
} else if r.Method == MethodRDGIN {
|
|
||||||
legacyConnections.Inc()
|
|
||||||
defer legacyConnections.Dec()
|
|
||||||
|
|
||||||
var remote net.Conn
|
|
||||||
|
|
||||||
in, err := transport.NewLegacy(w)
|
|
||||||
if err != nil {
|
|
||||||
log.Printf("cannot hijack connection to support RDG IN data channel: %s", err)
|
|
||||||
return
|
|
||||||
}
|
|
||||||
defer in.Close()
|
|
||||||
|
|
||||||
if s.TransportIn == nil {
|
|
||||||
s.TransportIn = in
|
|
||||||
c.Set(connId, s, cache.DefaultExpiration)
|
|
||||||
|
|
||||||
//log.Printf("Opening RDGIN for client %s", in.RemoteAddr().String())
|
|
||||||
in.SendAccept(false)
|
|
||||||
|
|
||||||
// read some initial data
|
|
||||||
in.Drain()
|
|
||||||
|
|
||||||
log.Printf("Reading packet from client %s", in.Conn.RemoteAddr().String())
|
|
||||||
handler := protocol.NewHandler(in)
|
|
||||||
for {
|
|
||||||
pt, sz, pkt, err := handler.ReadMessage()
|
|
||||||
if err != nil {
|
|
||||||
log.Printf("Cannot read message from stream %s", err)
|
|
||||||
return
|
|
||||||
}
|
|
||||||
|
|
||||||
switch pt {
|
|
||||||
case PKT_TYPE_HANDSHAKE_REQUEST:
|
|
||||||
major, minor, _, auth := readHandshake(pkt)
|
|
||||||
msg := handshakeResponse(major, minor, auth)
|
|
||||||
s.TransportOut.WritePacket(msg)
|
|
||||||
case PKT_TYPE_TUNNEL_CREATE:
|
|
||||||
readCreateTunnelRequest(pkt)
|
|
||||||
/*if _, found := tokens.Get(cookie); found == false {
|
|
||||||
log.Printf("Invalid PAA cookie: %s from %s", cookie, in.Conn.RemoteAddr())
|
|
||||||
return
|
|
||||||
}*/
|
|
||||||
msg := createTunnelResponse()
|
|
||||||
s.TransportOut.WritePacket(msg)
|
|
||||||
case PKT_TYPE_TUNNEL_AUTH:
|
|
||||||
readTunnelAuthRequest(pkt)
|
|
||||||
msg := createTunnelAuthResponse()
|
|
||||||
s.TransportOut.WritePacket(msg)
|
|
||||||
case PKT_TYPE_CHANNEL_CREATE:
|
|
||||||
server, port := readChannelCreateRequest(pkt)
|
|
||||||
log.Printf("Establishing connection to RDP server: %s on port %d (%x)", server, port, server)
|
|
||||||
remote, err = net.DialTimeout(
|
|
||||||
"tcp",
|
|
||||||
net.JoinHostPort(server, strconv.Itoa(int(port))),
|
|
||||||
time.Second * 15)
|
|
||||||
if err != nil {
|
|
||||||
log.Printf("Error connecting to %s, %d, %s", server, port, err)
|
|
||||||
return
|
|
||||||
}
|
|
||||||
log.Printf("Connection established")
|
|
||||||
msg := createChannelCreateResponse()
|
|
||||||
s.TransportOut.WritePacket(msg)
|
|
||||||
|
|
||||||
// Make sure to start the flow from the RDP server first otherwise connections
|
|
||||||
// might hang eventually
|
|
||||||
go sendDataPacket(remote, s.TransportOut)
|
|
||||||
case PKT_TYPE_DATA:
|
|
||||||
forwardDataPacket(remote, pkt)
|
|
||||||
case PKT_TYPE_KEEPALIVE:
|
|
||||||
// avoid concurrency issues
|
|
||||||
// s.TransportOut.Write(createPacket(PKT_TYPE_KEEPALIVE, []byte{}))
|
|
||||||
case PKT_TYPE_CLOSE_CHANNEL:
|
|
||||||
s.TransportIn.Close()
|
|
||||||
s.TransportOut.Close()
|
|
||||||
break
|
|
||||||
default:
|
|
||||||
log.Printf("Unknown packet (size %d): %x", sz, pkt)
|
|
||||||
}
|
|
||||||
}
|
|
||||||
}
|
|
||||||
}
|
|
||||||
}
|
|
||||||
|
|
||||||
// Creates a packet the is a response to a handshake request
|
|
||||||
// HTTP_EXTENDED_AUTH_SSPI_NTLM is not supported in Linux
|
|
||||||
// but could be in Windows. However the NTLM protocol is insecure
|
|
||||||
func handshakeResponse(major byte, minor byte, auth uint16) []byte {
|
|
||||||
var caps uint16
|
|
||||||
if conf.Caps.SmartCardAuth {
|
|
||||||
caps = caps | HTTP_EXTENDED_AUTH_PAA
|
|
||||||
}
|
|
||||||
if conf.Caps.TokenAuth {
|
|
||||||
caps = caps | HTTP_EXTENDED_AUTH_PAA
|
|
||||||
}
|
|
||||||
|
|
||||||
buf := new(bytes.Buffer)
|
|
||||||
binary.Write(buf, binary.LittleEndian, uint32(0)) // error_code
|
|
||||||
buf.Write([]byte{major, minor})
|
|
||||||
binary.Write(buf, binary.LittleEndian, uint16(0)) // server version
|
|
||||||
binary.Write(buf, binary.LittleEndian, uint16(caps)) // extended auth
|
|
||||||
|
|
||||||
return createPacket(PKT_TYPE_HANDSHAKE_RESPONSE, buf.Bytes())
|
|
||||||
}
|
|
||||||
|
|
||||||
func readHandshake(data []byte) (major byte, minor byte, version uint16, extAuth uint16) {
|
|
||||||
r := bytes.NewReader(data)
|
|
||||||
binary.Read(r, binary.LittleEndian, &major)
|
|
||||||
binary.Read(r, binary.LittleEndian, &minor)
|
|
||||||
binary.Read(r, binary.LittleEndian, &version)
|
|
||||||
binary.Read(r, binary.LittleEndian, &extAuth)
|
|
||||||
|
|
||||||
log.Printf("major: %d, minor: %d, version: %d, ext auth: %d", major, minor, version, extAuth)
|
|
||||||
return
|
|
||||||
}
|
|
||||||
|
|
||||||
func readCreateTunnelRequest(data []byte) (caps uint32, cookie string) {
|
|
||||||
var fields uint16
|
|
||||||
|
|
||||||
r := bytes.NewReader(data)
|
|
||||||
|
|
||||||
binary.Read(r, binary.LittleEndian, &caps)
|
|
||||||
binary.Read(r, binary.LittleEndian, &fields)
|
|
||||||
r.Seek(2, io.SeekCurrent)
|
|
||||||
|
|
||||||
if fields == HTTP_TUNNEL_PACKET_FIELD_PAA_COOKIE {
|
|
||||||
var size uint16
|
|
||||||
binary.Read(r, binary.LittleEndian, &size)
|
|
||||||
cookieB := make([]byte, size)
|
|
||||||
r.Read(cookieB)
|
|
||||||
cookie, _ = DecodeUTF16(cookieB)
|
|
||||||
}
|
|
||||||
log.Printf("Create tunnel caps: %d, cookie: %s", caps, cookie)
|
|
||||||
return
|
|
||||||
}
|
|
||||||
|
|
||||||
func createTunnelResponse() []byte {
|
|
||||||
buf := new(bytes.Buffer)
|
|
||||||
|
|
||||||
binary.Write(buf, binary.LittleEndian, uint16(0)) // server version
|
|
||||||
binary.Write(buf, binary.LittleEndian, uint32(0)) // error code
|
|
||||||
binary.Write(buf, binary.LittleEndian, uint16(HTTP_TUNNEL_RESPONSE_FIELD_TUNNEL_ID|HTTP_TUNNEL_RESPONSE_FIELD_CAPS)) // fields present
|
|
||||||
binary.Write(buf, binary.LittleEndian, uint16(0)) // reserved
|
|
||||||
binary.Write(buf, binary.LittleEndian, uint16(0)) // reserved
|
|
||||||
|
|
||||||
// tunnel id ?
|
|
||||||
binary.Write(buf, binary.LittleEndian, uint32(15))
|
|
||||||
// caps ?
|
|
||||||
binary.Write(buf, binary.LittleEndian, uint32(2))
|
|
||||||
|
|
||||||
return createPacket(PKT_TYPE_TUNNEL_RESPONSE, buf.Bytes())
|
|
||||||
}
|
|
||||||
|
|
||||||
func readTunnelAuthRequest(data []byte) {
|
|
||||||
buf := bytes.NewReader(data)
|
|
||||||
|
|
||||||
var size uint16
|
|
||||||
binary.Read(buf, binary.LittleEndian, &size)
|
|
||||||
clData := make([]byte, size)
|
|
||||||
binary.Read(buf, binary.LittleEndian, &clData)
|
|
||||||
clientName, _ := DecodeUTF16(clData)
|
|
||||||
log.Printf("Client: %s", clientName)
|
|
||||||
}
|
|
||||||
|
|
||||||
func createTunnelAuthResponse() []byte {
|
|
||||||
buf := new(bytes.Buffer)
|
|
||||||
|
|
||||||
binary.Write(buf, binary.LittleEndian, uint32(0)) // error code
|
|
||||||
binary.Write(buf, binary.LittleEndian, uint16(HTTP_TUNNEL_AUTH_RESPONSE_FIELD_REDIR_FLAGS|HTTP_TUNNEL_AUTH_RESPONSE_FIELD_IDLE_TIMEOUT)) // fields present
|
|
||||||
binary.Write(buf, binary.LittleEndian, uint16(0)) // reserved
|
|
||||||
|
|
||||||
// flags
|
|
||||||
var redir uint32
|
|
||||||
if conf.Caps.RedirectAll {
|
|
||||||
redir = HTTP_TUNNEL_REDIR_ENABLE_ALL
|
|
||||||
} else if conf.Caps.DisableRedirect {
|
|
||||||
redir = HTTP_TUNNEL_REDIR_DISABLE_ALL
|
|
||||||
} else {
|
|
||||||
if conf.Caps.DisableClipboard {
|
|
||||||
redir = redir | HTTP_TUNNEL_REDIR_DISABLE_CLIPBOARD
|
|
||||||
}
|
|
||||||
if conf.Caps.DisableDrive {
|
|
||||||
redir = redir | HTTP_TUNNEL_REDIR_DISABLE_DRIVE
|
|
||||||
}
|
|
||||||
if conf.Caps.DisablePnp {
|
|
||||||
redir = redir | HTTP_TUNNEL_REDIR_DISABLE_PNP
|
|
||||||
}
|
|
||||||
if conf.Caps.DisablePrinter {
|
|
||||||
redir = redir | HTTP_TUNNEL_REDIR_DISABLE_PRINTER
|
|
||||||
}
|
|
||||||
if conf.Caps.DisablePort {
|
|
||||||
redir = redir | HTTP_TUNNEL_REDIR_DISABLE_PORT
|
|
||||||
}
|
|
||||||
}
|
|
||||||
|
|
||||||
// idle timeout
|
|
||||||
timeout := conf.Caps.IdleTimeout
|
|
||||||
if timeout < 0 {
|
|
||||||
timeout = 0
|
|
||||||
}
|
|
||||||
|
|
||||||
binary.Write(buf, binary.LittleEndian, uint32(redir)) // redir flags
|
|
||||||
binary.Write(buf, binary.LittleEndian, uint32(timeout)) // timeout in minutes
|
|
||||||
|
|
||||||
return createPacket(PKT_TYPE_TUNNEL_AUTH_RESPONSE, buf.Bytes())
|
|
||||||
}
|
|
||||||
|
|
||||||
func readChannelCreateRequest(data []byte) (server string, port uint16) {
|
|
||||||
buf := bytes.NewReader(data)
|
|
||||||
|
|
||||||
var resourcesSize byte
|
|
||||||
var alternative byte
|
|
||||||
var protocol uint16
|
|
||||||
var nameSize uint16
|
|
||||||
|
|
||||||
binary.Read(buf, binary.LittleEndian, &resourcesSize)
|
|
||||||
binary.Read(buf, binary.LittleEndian, &alternative)
|
|
||||||
binary.Read(buf, binary.LittleEndian, &port)
|
|
||||||
binary.Read(buf, binary.LittleEndian, &protocol)
|
|
||||||
binary.Read(buf, binary.LittleEndian, &nameSize)
|
|
||||||
|
|
||||||
nameData := make([]byte, nameSize)
|
|
||||||
binary.Read(buf, binary.LittleEndian, &nameData)
|
|
||||||
|
|
||||||
log.Printf("Name data %q", nameData)
|
|
||||||
server, _ = DecodeUTF16(nameData)
|
|
||||||
|
|
||||||
log.Printf("Should connect to %s on port %d", server, port)
|
|
||||||
return
|
|
||||||
}
|
|
||||||
|
|
||||||
func createChannelCreateResponse() []byte {
|
|
||||||
buf := new(bytes.Buffer)
|
|
||||||
|
|
||||||
binary.Write(buf, binary.LittleEndian, uint32(0)) // error code
|
|
||||||
//binary.Write(buf, binary.LittleEndian, uint16(HTTP_CHANNEL_RESPONSE_FIELD_CHANNELID | HTTP_CHANNEL_RESPONSE_FIELD_AUTHNCOOKIE | HTTP_CHANNEL_RESPONSE_FIELD_UDPPORT)) // fields present
|
|
||||||
binary.Write(buf, binary.LittleEndian, uint16(0)) // fields
|
|
||||||
binary.Write(buf, binary.LittleEndian, uint16(0)) // reserved
|
|
||||||
|
|
||||||
// optional fields
|
|
||||||
// channel id uint32 (4)
|
|
||||||
// udp port uint16 (2)
|
|
||||||
// udp auth cookie 1 byte for side channel
|
|
||||||
// length uint16
|
|
||||||
|
|
||||||
return createPacket(PKT_TYPE_CHANNEL_RESPONSE, buf.Bytes())
|
|
||||||
}
|
|
||||||
|
|
||||||
func createPacket(pktType uint16, data []byte) (packet []byte) {
|
|
||||||
size := len(data) + 8
|
|
||||||
buf := new(bytes.Buffer)
|
|
||||||
|
|
||||||
binary.Write(buf, binary.LittleEndian, uint16(pktType))
|
|
||||||
binary.Write(buf, binary.LittleEndian, uint16(0)) // reserved
|
|
||||||
binary.Write(buf, binary.LittleEndian, uint32(size))
|
|
||||||
buf.Write(data)
|
|
||||||
|
|
||||||
return buf.Bytes()
|
|
||||||
}
|
|
||||||
|
|
||||||
func forwardDataPacket(conn net.Conn, data []byte) {
|
|
||||||
buf := bytes.NewReader(data)
|
|
||||||
|
|
||||||
var cblen uint16
|
|
||||||
binary.Read(buf, binary.LittleEndian, &cblen)
|
|
||||||
//log.Printf("Received PKT_DATA %d", cblen)
|
|
||||||
pkt := make([]byte, cblen)
|
|
||||||
binary.Read(buf, binary.LittleEndian, &pkt)
|
|
||||||
//n, _ := buf.Read(pkt)
|
|
||||||
//log.Printf("CBLEN: %d, N: %d", cblen, n)
|
|
||||||
//log.Printf("DATA FROM CLIENT %q", pkt)
|
|
||||||
conn.Write(pkt)
|
|
||||||
}
|
|
||||||
|
|
||||||
func sendDataPacket(connIn net.Conn, connOut transport.Transport) {
|
|
||||||
defer connIn.Close()
|
|
||||||
b1 := new(bytes.Buffer)
|
|
||||||
buf := make([]byte, 4086)
|
|
||||||
for {
|
|
||||||
n, err := connIn.Read(buf)
|
|
||||||
binary.Write(b1, binary.LittleEndian, uint16(n))
|
|
||||||
log.Printf("RDP SIZE: %d", n)
|
|
||||||
if err != nil {
|
|
||||||
log.Printf("Error reading from conn %s", err)
|
|
||||||
break
|
|
||||||
}
|
|
||||||
b1.Write(buf[:n])
|
|
||||||
connOut.WritePacket(createPacket(PKT_TYPE_DATA, b1.Bytes()))
|
|
||||||
b1.Reset()
|
|
||||||
}
|
|
||||||
}
|
|
||||||
|
|
||||||
func DecodeUTF16(b []byte) (string, error) {
|
|
||||||
if len(b)%2 != 0 {
|
|
||||||
return "", fmt.Errorf("must have even length byte slice")
|
|
||||||
}
|
|
||||||
|
|
||||||
u16s := make([]uint16, 1)
|
|
||||||
ret := &bytes.Buffer{}
|
|
||||||
b8buf := make([]byte, 4)
|
|
||||||
|
|
||||||
lb := len(b)
|
|
||||||
for i := 0; i < lb; i += 2 {
|
|
||||||
u16s[0] = uint16(b[i]) + (uint16(b[i+1]) << 8)
|
|
||||||
r := utf16.Decode(u16s)
|
|
||||||
n := utf8.EncodeRune(b8buf, r[0])
|
|
||||||
ret.Write(b8buf[:n])
|
|
||||||
}
|
|
||||||
|
|
||||||
bret := ret.Bytes()
|
|
||||||
if len(bret) > 0 && bret[len(bret)-1] == '\x00' {
|
|
||||||
bret = bret[:len(bret)-1]
|
|
||||||
}
|
|
||||||
return string(bret), nil
|
|
||||||
}
|
|
||||||
|
|
||||||
// UTF-16 endian byte order
|
|
||||||
const (
|
|
||||||
unknownEndian = iota
|
|
||||||
bigEndian
|
|
||||||
littleEndian
|
|
||||||
)
|
|
||||||
|
|
||||||
// dropCREndian drops a terminal \r from the endian data.
|
|
||||||
func dropCREndian(data []byte, t1, t2 byte) []byte {
|
|
||||||
if len(data) > 1 {
|
|
||||||
if data[len(data)-2] == t1 && data[len(data)-1] == t2 {
|
|
||||||
return data[0 : len(data)-2]
|
|
||||||
}
|
|
||||||
}
|
|
||||||
return data
|
|
||||||
}
|
|
||||||
|
|
||||||
// dropCRBE drops a terminal \r from the big endian data.
|
|
||||||
func dropCRBE(data []byte) []byte {
|
|
||||||
return dropCREndian(data, '\x00', '\r')
|
|
||||||
}
|
|
||||||
|
|
||||||
// dropCRLE drops a terminal \r from the little endian data.
|
|
||||||
func dropCRLE(data []byte) []byte {
|
|
||||||
return dropCREndian(data, '\r', '\x00')
|
|
||||||
}
|
|
||||||
|
|
||||||
// dropCR drops a terminal \r from the data.
|
|
||||||
func dropCR(data []byte) ([]byte, int) {
|
|
||||||
var endian = unknownEndian
|
|
||||||
switch ld := len(data); {
|
|
||||||
case ld != len(dropCRLE(data)):
|
|
||||||
endian = littleEndian
|
|
||||||
case ld != len(dropCRBE(data)):
|
|
||||||
endian = bigEndian
|
|
||||||
}
|
|
||||||
return data, endian
|
|
||||||
}
|
|
||||||
Loading…
Add table
Add a link
Reference in a new issue