refactor: Modular inbounds/outbounds

protocol/group/selector.go

@@ -0,0 +1,177 @@
+package group
+
+import (
+	"context"
+	"net"
+
+	"github.com/sagernet/sing-box/adapter"
+	"github.com/sagernet/sing-box/adapter/outbound"
+	"github.com/sagernet/sing-box/common/interrupt"
+	C "github.com/sagernet/sing-box/constant"
+	"github.com/sagernet/sing-box/log"
+	"github.com/sagernet/sing-box/option"
+	E "github.com/sagernet/sing/common/exceptions"
+	"github.com/sagernet/sing/common/logger"
+	M "github.com/sagernet/sing/common/metadata"
+	N "github.com/sagernet/sing/common/network"
+	"github.com/sagernet/sing/service"
+)
+
+func RegisterSelector(registry *outbound.Registry) {
+	outbound.Register[option.SelectorOutboundOptions](registry, C.TypeSelector, NewSelector)
+}
+
+var _ adapter.OutboundGroup = (*Selector)(nil)
+
+type Selector struct {
+	outbound.Adapter
+	ctx                          context.Context
+	router                       adapter.Router
+	logger                       logger.ContextLogger
+	tags                         []string
+	defaultTag                   string
+	outbounds                    map[string]adapter.Outbound
+	selected                     adapter.Outbound
+	interruptGroup               *interrupt.Group
+	interruptExternalConnections bool
+}
+
+func NewSelector(ctx context.Context, router adapter.Router, logger log.ContextLogger, tag string, options option.SelectorOutboundOptions) (adapter.Outbound, error) {
+	outbound := &Selector{
+		Adapter:                      outbound.NewAdapter(C.TypeSelector, nil, tag, options.Outbounds),
+		ctx:                          ctx,
+		router:                       router,
+		logger:                       logger,
+		tags:                         options.Outbounds,
+		defaultTag:                   options.Default,
+		outbounds:                    make(map[string]adapter.Outbound),
+		interruptGroup:               interrupt.NewGroup(),
+		interruptExternalConnections: options.InterruptExistConnections,
+	}
+	if len(outbound.tags) == 0 {
+		return nil, E.New("missing tags")
+	}
+	return outbound, nil
+}
+
+func (s *Selector) Network() []string {
+	if s.selected == nil {
+		return []string{N.NetworkTCP, N.NetworkUDP}
+	}
+	return s.selected.Network()
+}
+
+func (s *Selector) Start() error {
+	for i, tag := range s.tags {
+		detour, loaded := s.router.Outbound(tag)
+		if !loaded {
+			return E.New("outbound ", i, " not found: ", tag)
+		}
+		s.outbounds[tag] = detour
+	}
+
+	if s.Tag() != "" {
+		cacheFile := service.FromContext[adapter.CacheFile](s.ctx)
+		if cacheFile != nil {
+			selected := cacheFile.LoadSelected(s.Tag())
+			if selected != "" {
+				detour, loaded := s.outbounds[selected]
+				if loaded {
+					s.selected = detour
+					return nil
+				}
+			}
+		}
+	}
+
+	if s.defaultTag != "" {
+		detour, loaded := s.outbounds[s.defaultTag]
+		if !loaded {
+			return E.New("default outbound not found: ", s.defaultTag)
+		}
+		s.selected = detour
+		return nil
+	}
+
+	s.selected = s.outbounds[s.tags[0]]
+	return nil
+}
+
+func (s *Selector) Now() string {
+	selected := s.selected
+	if selected == nil {
+		return s.tags[0]
+	}
+	return selected.Tag()
+}
+
+func (s *Selector) All() []string {
+	return s.tags
+}
+
+func (s *Selector) SelectOutbound(tag string) bool {
+	detour, loaded := s.outbounds[tag]
+	if !loaded {
+		return false
+	}
+	if s.selected == detour {
+		return true
+	}
+	s.selected = detour
+	if s.Tag() != "" {
+		cacheFile := service.FromContext[adapter.CacheFile](s.ctx)
+		if cacheFile != nil {
+			err := cacheFile.StoreSelected(s.Tag(), tag)
+			if err != nil {
+				s.logger.Error("store selected: ", err)
+			}
+		}
+	}
+	s.interruptGroup.Interrupt(s.interruptExternalConnections)
+	return true
+}
+
+func (s *Selector) DialContext(ctx context.Context, network string, destination M.Socksaddr) (net.Conn, error) {
+	conn, err := s.selected.DialContext(ctx, network, destination)
+	if err != nil {
+		return nil, err
+	}
+	return s.interruptGroup.NewConn(conn, interrupt.IsExternalConnectionFromContext(ctx)), nil
+}
+
+func (s *Selector) ListenPacket(ctx context.Context, destination M.Socksaddr) (net.PacketConn, error) {
+	conn, err := s.selected.ListenPacket(ctx, destination)
+	if err != nil {
+		return nil, err
+	}
+	return s.interruptGroup.NewPacketConn(conn, interrupt.IsExternalConnectionFromContext(ctx)), nil
+}
+
+// TODO
+// Deprecated
+func (s *Selector) NewConnection(ctx context.Context, conn net.Conn, metadata adapter.InboundContext) error {
+	ctx = interrupt.ContextWithIsExternalConnection(ctx)
+	if legacyHandler, ok := s.selected.(adapter.ConnectionHandler); ok {
+		return legacyHandler.NewConnection(ctx, conn, metadata)
+	} else {
+		return outbound.NewConnection(ctx, s.selected, conn, metadata)
+	}
+}
+
+// TODO
+// Deprecated
+func (s *Selector) NewPacketConnection(ctx context.Context, conn N.PacketConn, metadata adapter.InboundContext) error {
+	ctx = interrupt.ContextWithIsExternalConnection(ctx)
+	if legacyHandler, ok := s.selected.(adapter.PacketConnectionHandler); ok {
+		return legacyHandler.NewPacketConnection(ctx, conn, metadata)
+	} else {
+		return outbound.NewPacketConnection(ctx, s.selected, conn, metadata)
+	}
+}
+
+func RealTag(detour adapter.Outbound) string {
+	if group, isGroup := detour.(adapter.OutboundGroup); isGroup {
+		return group.Now()
+	}
+	return detour.Tag()
+}