mirror of
https://github.com/netbirdio/netbird.git
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Add embedded VNC server with JWT auth, DXGI capture, and dashboard integration
This commit is contained in:
Viktor Liu
360
client/wasm/internal/vnc/proxy.go
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360
client/wasm/internal/vnc/proxy.go
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@@ -0,0 +1,360 @@
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//go:build js
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package vnc
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import (
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"context"
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"fmt"
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"io"
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"net"
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"sync"
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"sync/atomic"
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"syscall/js"
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"time"
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log "github.com/sirupsen/logrus"
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)
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const (
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vncProxyHost = "vnc.proxy.local"
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vncProxyScheme = "ws"
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vncDialTimeout = 15 * time.Second
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// Connection modes matching server/server.go constants.
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modeAttach byte = 0
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modeSession byte = 1
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)
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// VNCProxy bridges WebSocket connections from noVNC in the browser
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// to TCP VNC server connections through the NetBird tunnel.
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type VNCProxy struct {
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nbClient interface {
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Dial(ctx context.Context, network, address string) (net.Conn, error)
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}
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activeConnections map[string]*vncConnection
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destinations map[string]vncDestination
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// pendingHandlers holds the js.Func for handleVNCWebSocket_<id> between
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// CreateProxy and handleWebSocketConnection so we can move it onto the
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// vncConnection for later release.
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pendingHandlers map[string]js.Func
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mu sync.Mutex
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nextID atomic.Uint64
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}
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type vncDestination struct {
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address string
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mode byte
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username string
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jwt string
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sessionID uint32 // Windows session ID (0 = auto/console)
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}
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type vncConnection struct {
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id string
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destination vncDestination
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mu sync.Mutex
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vncConn net.Conn
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wsHandlers js.Value
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ctx context.Context
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cancel context.CancelFunc
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// Go-side callbacks exposed to JS. js.FuncOf pins the Go closure in a
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// global handle map and MUST be released, otherwise every connection
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// leaks the Go memory the closure captures.
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wsHandlerFn js.Func
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onMessageFn js.Func
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onCloseFn js.Func
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}
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// NewVNCProxy creates a new VNC proxy.
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func NewVNCProxy(client interface {
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Dial(ctx context.Context, network, address string) (net.Conn, error)
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}) *VNCProxy {
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return &VNCProxy{
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nbClient: client,
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activeConnections: make(map[string]*vncConnection),
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}
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}
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// CreateProxy creates a new proxy endpoint for the given VNC destination.
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// mode is "attach" (capture current display) or "session" (virtual session).
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// username is required for session mode.
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// Returns a JS Promise that resolves to the WebSocket proxy URL.
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func (p *VNCProxy) CreateProxy(hostname, port, mode, username, jwt string, sessionID uint32) js.Value {
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address := fmt.Sprintf("%s:%s", hostname, port)
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var m byte
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if mode == "session" {
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m = modeSession
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}
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dest := vncDestination{
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address: address,
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mode: m,
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username: username,
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jwt: jwt,
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sessionID: sessionID,
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}
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return js.Global().Get("Promise").New(js.FuncOf(func(_ js.Value, args []js.Value) any {
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resolve := args[0]
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go func() {
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proxyID := fmt.Sprintf("vnc_proxy_%d", p.nextID.Add(1))
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p.mu.Lock()
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if p.destinations == nil {
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p.destinations = make(map[string]vncDestination)
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}
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p.destinations[proxyID] = dest
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p.mu.Unlock()
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proxyURL := fmt.Sprintf("%s://%s/%s", vncProxyScheme, vncProxyHost, proxyID)
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handlerFn := js.FuncOf(func(_ js.Value, args []js.Value) any {
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if len(args) < 1 {
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return js.ValueOf("error: requires WebSocket argument")
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}
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p.handleWebSocketConnection(args[0], proxyID)
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return nil
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})
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p.mu.Lock()
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if p.pendingHandlers == nil {
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p.pendingHandlers = make(map[string]js.Func)
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}
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p.pendingHandlers[proxyID] = handlerFn
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p.mu.Unlock()
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js.Global().Set(fmt.Sprintf("handleVNCWebSocket_%s", proxyID), handlerFn)
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log.Infof("created VNC proxy: %s -> %s (mode=%s, user=%s)", proxyURL, address, mode, username)
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resolve.Invoke(proxyURL)
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}()
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return nil
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}))
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}
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func (p *VNCProxy) handleWebSocketConnection(ws js.Value, proxyID string) {
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p.mu.Lock()
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dest, ok := p.destinations[proxyID]
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handlerFn := p.pendingHandlers[proxyID]
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delete(p.pendingHandlers, proxyID)
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p.mu.Unlock()
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if !ok {
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log.Errorf("no destination for VNC proxy %s", proxyID)
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return
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}
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ctx, cancel := context.WithCancel(context.Background())
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conn := &vncConnection{
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id: proxyID,
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destination: dest,
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wsHandlers: ws,
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ctx: ctx,
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cancel: cancel,
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wsHandlerFn: handlerFn,
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}
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p.mu.Lock()
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p.activeConnections[proxyID] = conn
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p.mu.Unlock()
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p.setupWebSocketHandlers(ws, conn)
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go p.connectToVNC(conn)
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log.Infof("VNC proxy WebSocket connection established for %s", proxyID)
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}
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func (p *VNCProxy) setupWebSocketHandlers(ws js.Value, conn *vncConnection) {
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conn.onMessageFn = js.FuncOf(func(_ js.Value, args []js.Value) any {
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if len(args) < 1 {
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return nil
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}
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data := args[0]
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go p.handleWebSocketMessage(conn, data)
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return nil
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})
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ws.Set("onGoMessage", conn.onMessageFn)
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conn.onCloseFn = js.FuncOf(func(_ js.Value, _ []js.Value) any {
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log.Debug("VNC WebSocket closed by JavaScript")
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conn.cancel()
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return nil
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})
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ws.Set("onGoClose", conn.onCloseFn)
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}
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func (p *VNCProxy) handleWebSocketMessage(conn *vncConnection, data js.Value) {
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if !data.InstanceOf(js.Global().Get("Uint8Array")) {
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return
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}
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length := data.Get("length").Int()
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buf := make([]byte, length)
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js.CopyBytesToGo(buf, data)
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conn.mu.Lock()
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vncConn := conn.vncConn
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conn.mu.Unlock()
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if vncConn == nil {
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return
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}
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if _, err := vncConn.Write(buf); err != nil {
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log.Debugf("write to VNC server: %v", err)
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}
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}
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func (p *VNCProxy) connectToVNC(conn *vncConnection) {
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ctx, cancel := context.WithTimeout(conn.ctx, vncDialTimeout)
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defer cancel()
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vncConn, err := p.nbClient.Dial(ctx, "tcp", conn.destination.address)
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if err != nil {
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log.Errorf("VNC connect to %s: %v", conn.destination.address, err)
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// Close the WebSocket so noVNC fires a disconnect event.
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if conn.wsHandlers.Get("close").Truthy() {
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conn.wsHandlers.Call("close", 1006, fmt.Sprintf("connect to peer: %v", err))
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}
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p.cleanupConnection(conn)
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return
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}
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conn.mu.Lock()
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conn.vncConn = vncConn
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conn.mu.Unlock()
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// Send the NetBird VNC session header before the RFB handshake.
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if err := p.sendSessionHeader(vncConn, conn.destination); err != nil {
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log.Errorf("send VNC session header: %v", err)
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p.cleanupConnection(conn)
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return
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}
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// WS→TCP is handled by the onGoMessage handler set in setupWebSocketHandlers,
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// which writes directly to the VNC connection as data arrives from JS.
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// Only the TCP→WS direction needs a read loop here.
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go p.forwardConnToWS(conn)
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<-conn.ctx.Done()
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p.cleanupConnection(conn)
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}
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// sendSessionHeader writes mode, username, and JWT to the VNC server.
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// Format: [mode: 1 byte] [username_len: 2 bytes BE] [username: N bytes]
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//
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// [jwt_len: 2 bytes BE] [jwt: N bytes]
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func (p *VNCProxy) sendSessionHeader(conn net.Conn, dest vncDestination) error {
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usernameBytes := []byte(dest.username)
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jwtBytes := []byte(dest.jwt)
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// Format: [mode:1] [username_len:2] [username:N] [jwt_len:2] [jwt:N] [session_id:4]
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hdr := make([]byte, 3+len(usernameBytes)+2+len(jwtBytes)+4)
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hdr[0] = dest.mode
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hdr[1] = byte(len(usernameBytes) >> 8)
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hdr[2] = byte(len(usernameBytes))
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off := 3
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copy(hdr[off:], usernameBytes)
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off += len(usernameBytes)
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hdr[off] = byte(len(jwtBytes) >> 8)
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hdr[off+1] = byte(len(jwtBytes))
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off += 2
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copy(hdr[off:], jwtBytes)
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off += len(jwtBytes)
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hdr[off] = byte(dest.sessionID >> 24)
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hdr[off+1] = byte(dest.sessionID >> 16)
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hdr[off+2] = byte(dest.sessionID >> 8)
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hdr[off+3] = byte(dest.sessionID)
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_, err := conn.Write(hdr)
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return err
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}
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func (p *VNCProxy) forwardConnToWS(conn *vncConnection) {
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buf := make([]byte, 32*1024)
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for {
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if conn.ctx.Err() != nil {
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return
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}
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// Set a read deadline so we detect dead connections instead of
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// blocking forever when the remote peer dies.
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conn.mu.Lock()
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vc := conn.vncConn
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conn.mu.Unlock()
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if vc == nil {
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return
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}
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vc.SetReadDeadline(time.Now().Add(30 * time.Second))
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n, err := vc.Read(buf)
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if err != nil {
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if conn.ctx.Err() != nil {
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return
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}
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if netErr, ok := err.(interface{ Timeout() bool }); ok && netErr.Timeout() {
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// Read timeout: connection might be stale. Send a ping-like
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// empty read to check. If the connection is truly dead, the
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// next iteration will fail too and we'll close.
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continue
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}
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if err != io.EOF {
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log.Debugf("read from VNC connection: %v", err)
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}
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// Close the WebSocket to notify noVNC.
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if conn.wsHandlers.Get("close").Truthy() {
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conn.wsHandlers.Call("close", 1006, "VNC connection lost")
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}
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return
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}
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if n > 0 {
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p.sendToWebSocket(conn, buf[:n])
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}
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}
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}
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func (p *VNCProxy) sendToWebSocket(conn *vncConnection, data []byte) {
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if conn.wsHandlers.Get("receiveFromGo").Truthy() {
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uint8Array := js.Global().Get("Uint8Array").New(len(data))
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js.CopyBytesToJS(uint8Array, data)
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conn.wsHandlers.Call("receiveFromGo", uint8Array.Get("buffer"))
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} else if conn.wsHandlers.Get("send").Truthy() {
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uint8Array := js.Global().Get("Uint8Array").New(len(data))
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js.CopyBytesToJS(uint8Array, data)
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conn.wsHandlers.Call("send", uint8Array.Get("buffer"))
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}
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}
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func (p *VNCProxy) cleanupConnection(conn *vncConnection) {
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log.Debugf("cleaning up VNC connection %s", conn.id)
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conn.cancel()
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conn.mu.Lock()
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vncConn := conn.vncConn
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conn.vncConn = nil
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conn.mu.Unlock()
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if vncConn != nil {
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if err := vncConn.Close(); err != nil {
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log.Debugf("close VNC connection: %v", err)
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}
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}
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// Remove the global JS handler registered in CreateProxy.
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globalName := fmt.Sprintf("handleVNCWebSocket_%s", conn.id)
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js.Global().Delete(globalName)
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// Release all js.Func handles; js.FuncOf pins the Go closure and the
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// allocations it captures until Release is called.
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conn.wsHandlerFn.Release()
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conn.onMessageFn.Release()
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conn.onCloseFn.Release()
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p.mu.Lock()
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delete(p.activeConnections, conn.id)
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delete(p.destinations, conn.id)
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delete(p.pendingHandlers, conn.id)
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p.mu.Unlock()
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}
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