Add bridge outbound

protocol/bridge/outbound.go

@@ -0,0 +1,90 @@
+package bridge
+
+import (
+	"context"
+	"net"
+	"net/netip"
+
+	"github.com/sagernet/sing-box/adapter"
+	"github.com/sagernet/sing-box/adapter/outbound"
+	C "github.com/sagernet/sing-box/constant"
+	"github.com/sagernet/sing-box/log"
+	"github.com/sagernet/sing-box/option"
+	"github.com/sagernet/sing-tun"
+	E "github.com/sagernet/sing/common/exceptions"
+	M "github.com/sagernet/sing/common/metadata"
+	N "github.com/sagernet/sing/common/network"
+	"github.com/sagernet/sing/service"
+)
+
+func RegisterOutbound(registry *outbound.Registry) {
+	outbound.Register[option.BridgeOutboundOptions](registry, C.TypeBridge, NewOutbound)
+}
+
+var (
+	_ adapter.Outbound     = (*Outbound)(nil)
+	_ adapter.FlowOutbound = (*Outbound)(nil)
+	_ adapter.Lifecycle    = (*Outbound)(nil)
+)
+
+type Backend interface {
+	adapter.Lifecycle
+	tun.Port
+}
+
+type Outbound struct {
+	outbound.Adapter
+	backend Backend
+}
+
+func NewOutbound(ctx context.Context, router adapter.Router, logger log.ContextLogger, tag string, options option.BridgeOutboundOptions) (adapter.Outbound, error) {
+	networkManager := service.FromContext[adapter.NetworkManager](ctx)
+	outboundBackend, err := newBackend(ctx, logger, networkManager, tag, options)
+	if err != nil {
+		return nil, err
+	}
+	return &Outbound{
+		Adapter: outbound.NewAdapter(C.TypeBridge, tag, []string{N.NetworkTCP, N.NetworkUDP, N.NetworkICMP}, nil),
+		backend: outboundBackend,
+	}, nil
+}
+
+func (o *Outbound) Start(stage adapter.StartStage) error {
+	return o.backend.Start(stage)
+}
+
+func (o *Outbound) Close() error {
+	return o.backend.Close()
+}
+
+func (o *Outbound) SupportsFlow(network string) bool {
+	return true
+}
+
+func (o *Outbound) PortAddresses() (netip.Addr, netip.Addr) {
+	return o.backend.PortAddresses()
+}
+
+func (o *Outbound) PortMTU() uint32 {
+	return o.backend.PortMTU()
+}
+
+func (o *Outbound) AttachReturn(returnPath tun.Return) error {
+	return o.backend.AttachReturn(returnPath)
+}
+
+func (o *Outbound) DetachReturn(returnPath tun.Return) error {
+	return o.backend.DetachReturn(returnPath)
+}
+
+func (o *Outbound) WritePackets(packets [][]byte) error {
+	return o.backend.WritePackets(packets)
+}
+
+func (o *Outbound) DialContext(ctx context.Context, network string, destination M.Socksaddr) (net.Conn, error) {
+	return nil, E.New("Only L3 traffic is supported by bridge")
+}
+
+func (o *Outbound) ListenPacket(ctx context.Context, destination M.Socksaddr) (net.PacketConn, error) {
+	return nil, E.New("Only L3 traffic is supported by bridge")
+}