chore: don't retry when rejected loopback connection

component/loopback/detector.go

@@ -0,0 +1,78 @@
+package loopback
+
+import (
+	"errors"
+	"fmt"
+	"net/netip"
+
+	"github.com/metacubex/mihomo/common/callback"
+	C "github.com/metacubex/mihomo/constant"
+
+	"github.com/puzpuzpuz/xsync/v3"
+)
+
+var ErrReject = errors.New("reject loopback connection")
+
+type Detector struct {
+	connMap       *xsync.MapOf[netip.AddrPort, struct{}]
+	packetConnMap *xsync.MapOf[netip.AddrPort, struct{}]
+}
+
+func NewDetector() *Detector {
+	return &Detector{
+		connMap:       xsync.NewMapOf[netip.AddrPort, struct{}](),
+		packetConnMap: xsync.NewMapOf[netip.AddrPort, struct{}](),
+	}
+}
+
+func (l *Detector) NewConn(conn C.Conn) C.Conn {
+	metadata := C.Metadata{}
+	if metadata.SetRemoteAddr(conn.LocalAddr()) != nil {
+		return conn
+	}
+	connAddr := metadata.AddrPort()
+	if !connAddr.IsValid() {
+		return conn
+	}
+	l.connMap.Store(connAddr, struct{}{})
+	return callback.NewCloseCallbackConn(conn, func() {
+		l.connMap.Delete(connAddr)
+	})
+}
+
+func (l *Detector) NewPacketConn(conn C.PacketConn) C.PacketConn {
+	metadata := C.Metadata{}
+	if metadata.SetRemoteAddr(conn.LocalAddr()) != nil {
+		return conn
+	}
+	connAddr := metadata.AddrPort()
+	if !connAddr.IsValid() {
+		return conn
+	}
+	l.packetConnMap.Store(connAddr, struct{}{})
+	return callback.NewCloseCallbackPacketConn(conn, func() {
+		l.packetConnMap.Delete(connAddr)
+	})
+}
+
+func (l *Detector) CheckConn(metadata *C.Metadata) error {
+	connAddr := metadata.SourceAddrPort()
+	if !connAddr.IsValid() {
+		return nil
+	}
+	if _, ok := l.connMap.Load(connAddr); ok {
+		return fmt.Errorf("%w to: %s", ErrReject, metadata.RemoteAddress())
+	}
+	return nil
+}
+
+func (l *Detector) CheckPacketConn(metadata *C.Metadata) error {
+	connAddr := metadata.SourceAddrPort()
+	if !connAddr.IsValid() {
+		return nil
+	}
+	if _, ok := l.packetConnMap.Load(connAddr); ok {
+		return fmt.Errorf("%w to: %s", ErrReject, metadata.RemoteAddress())
+	}
+	return nil
+}