initial commit

connector/relay/bind.go

@@ -0,0 +1,133 @@
+package relay
+
+import (
+	"context"
+	"fmt"
+	"net"
+	"strconv"
+
+	"github.com/go-gost/gost/v3/pkg/common/util/udp"
+	"github.com/go-gost/gost/v3/pkg/connector"
+	"github.com/go-gost/gost/v3/pkg/logger"
+	"github.com/go-gost/relay"
+	"github.com/go-gost/x/internal/util/mux"
+	relay_util "github.com/go-gost/x/internal/util/relay"
+)
+
+// Bind implements connector.Binder.
+func (c *relayConnector) Bind(ctx context.Context, conn net.Conn, network, address string, opts ...connector.BindOption) (net.Listener, error) {
+	log := c.options.Logger.WithFields(map[string]any{
+		"network": network,
+		"address": address,
+	})
+	log.Infof("bind on %s/%s", address, network)
+
+	options := connector.BindOptions{}
+	for _, opt := range opts {
+		opt(&options)
+	}
+
+	switch network {
+	case "tcp", "tcp4", "tcp6":
+		return c.bindTCP(ctx, conn, network, address, log)
+	case "udp", "udp4", "udp6":
+		return c.bindUDP(ctx, conn, network, address, &options, log)
+	default:
+		err := fmt.Errorf("network %s is unsupported", network)
+		log.Error(err)
+		return nil, err
+	}
+}
+
+func (c *relayConnector) bindTCP(ctx context.Context, conn net.Conn, network, address string, log logger.Logger) (net.Listener, error) {
+	laddr, err := c.bind(conn, relay.BIND, network, address)
+	if err != nil {
+		return nil, err
+	}
+	log.Debugf("bind on %s/%s OK", laddr, laddr.Network())
+
+	session, err := mux.ServerSession(conn)
+	if err != nil {
+		return nil, err
+	}
+
+	return &tcpListener{
+		addr:    laddr,
+		session: session,
+		logger:  log,
+	}, nil
+}
+
+func (c *relayConnector) bindUDP(ctx context.Context, conn net.Conn, network, address string, opts *connector.BindOptions, log logger.Logger) (net.Listener, error) {
+	laddr, err := c.bind(conn, relay.FUDP|relay.BIND, network, address)
+	if err != nil {
+		return nil, err
+	}
+	log.Debugf("bind on %s/%s OK", laddr, laddr.Network())
+
+	ln := udp.NewListener(
+		relay_util.UDPTunClientPacketConn(conn),
+		laddr,
+		opts.Backlog,
+		opts.UDPDataQueueSize, opts.UDPDataBufferSize,
+		opts.UDPConnTTL,
+		log)
+
+	return ln, nil
+}
+
+func (c *relayConnector) bind(conn net.Conn, cmd uint8, network, address string) (net.Addr, error) {
+	req := relay.Request{
+		Version: relay.Version1,
+		Flags:   cmd,
+	}
+
+	if c.options.Auth != nil {
+		pwd, _ := c.options.Auth.Password()
+		req.Features = append(req.Features, &relay.UserAuthFeature{
+			Username: c.options.Auth.Username(),
+			Password: pwd,
+		})
+	}
+	fa := &relay.AddrFeature{}
+	fa.ParseFrom(address)
+	req.Features = append(req.Features, fa)
+	if _, err := req.WriteTo(conn); err != nil {
+		return nil, err
+	}
+
+	// first reply, bind status
+	resp := relay.Response{}
+	if _, err := resp.ReadFrom(conn); err != nil {
+		return nil, err
+	}
+
+	if resp.Status != relay.StatusOK {
+		return nil, fmt.Errorf("bind on %s/%s failed", address, network)
+	}
+
+	var addr string
+	for _, f := range resp.Features {
+		if f.Type() == relay.FeatureAddr {
+			if fa, ok := f.(*relay.AddrFeature); ok {
+				addr = net.JoinHostPort(fa.Host, strconv.Itoa(int(fa.Port)))
+			}
+		}
+	}
+
+	var baddr net.Addr
+	var err error
+	switch network {
+	case "tcp", "tcp4", "tcp6":
+		baddr, err = net.ResolveTCPAddr(network, addr)
+	case "udp", "udp4", "udp6":
+		baddr, err = net.ResolveUDPAddr(network, addr)
+	default:
+		err = fmt.Errorf("unknown network %s", network)
+	}
+	if err != nil {
+		return nil, err
+	}
+
+	return baddr, nil
+}