chore: don't retry when rejected loopback connection

adapter/outbound/direct.go

@@ -3,18 +3,18 @@ package outbound
 import (
 	"context"
 	"errors"
-	"fmt"
 	"net/netip"
 
 	N "github.com/metacubex/mihomo/common/net"
 	"github.com/metacubex/mihomo/component/dialer"
+	"github.com/metacubex/mihomo/component/loopback"
 	"github.com/metacubex/mihomo/component/resolver"
 	C "github.com/metacubex/mihomo/constant"
 )
 
 type Direct struct {
 	*Base
-	loopBack *loopBackDetector
+	loopBack *loopback.Detector
 }
 
 type DirectOption struct {
@@ -24,8 +24,8 @@ type DirectOption struct {
 
 // DialContext implements C.ProxyAdapter
 func (d *Direct) DialContext(ctx context.Context, metadata *C.Metadata, opts ...dialer.Option) (C.Conn, error) {
-	if d.loopBack.CheckConn(metadata.SourceAddrPort()) {
+	if err := d.loopBack.CheckConn(metadata); err != nil {
-		return nil, fmt.Errorf("reject loopback connection to: %s", metadata.RemoteAddress())
+		return nil, err
 	}
 	opts = append(opts, dialer.WithResolver(resolver.DefaultResolver))
 	c, err := dialer.DialContext(ctx, "tcp", metadata.RemoteAddress(), d.Base.DialOptions(opts...)...)
@@ -38,8 +38,8 @@ func (d *Direct) DialContext(ctx context.Context, metadata *C.Metadata, opts ...
 
 // ListenPacketContext implements C.ProxyAdapter
 func (d *Direct) ListenPacketContext(ctx context.Context, metadata *C.Metadata, opts ...dialer.Option) (C.PacketConn, error) {
-	if d.loopBack.CheckPacketConn(metadata.SourceAddrPort()) {
+	if err := d.loopBack.CheckPacketConn(metadata); err != nil {
-		return nil, fmt.Errorf("reject loopback connection to: %s", metadata.RemoteAddress())
+		return nil, err
 	}
 	// net.UDPConn.WriteTo only working with *net.UDPAddr, so we need a net.UDPAddr
 	if !metadata.Resolved() {
@@ -68,7 +68,7 @@ func NewDirectWithOption(option DirectOption) *Direct {
 			rmark:  option.RoutingMark,
 			prefer: C.NewDNSPrefer(option.IPVersion),
 		},
-		loopBack: newLoopBackDetector(),
+		loopBack: loopback.NewDetector(),
 	}
 }
 
@@ -80,7 +80,7 @@ func NewDirect() *Direct {
 			udp:    true,
 			prefer: C.DualStack,
 		},
-		loopBack: newLoopBackDetector(),
+		loopBack: loopback.NewDetector(),
 	}
 }
 
@@ -92,6 +92,6 @@ func NewCompatible() *Direct {
 			udp:    true,
 			prefer: C.DualStack,
 		},
-		loopBack: newLoopBackDetector(),
+		loopBack: loopback.NewDetector(),
 	}
 }

component/loopback/detector.go

@@ -1,6 +1,8 @@
-package outbound
+package loopback
 
 import (
+	"errors"
+	"fmt"
 	"net/netip"
 
 	"github.com/metacubex/mihomo/common/callback"
@@ -9,19 +11,21 @@ import (
 	"github.com/puzpuzpuz/xsync/v3"
 )
 
-type loopBackDetector struct {
+var ErrReject = errors.New("reject loopback connection")
+
+type Detector struct {
 	connMap       *xsync.MapOf[netip.AddrPort, struct{}]
 	packetConnMap *xsync.MapOf[netip.AddrPort, struct{}]
 }
 
-func newLoopBackDetector() *loopBackDetector {
+func NewDetector() *Detector {
-	return &loopBackDetector{
+	return &Detector{
 		connMap:       xsync.NewMapOf[netip.AddrPort, struct{}](),
 		packetConnMap: xsync.NewMapOf[netip.AddrPort, struct{}](),
 	}
 }
 
-func (l *loopBackDetector) NewConn(conn C.Conn) C.Conn {
+func (l *Detector) NewConn(conn C.Conn) C.Conn {
 	metadata := C.Metadata{}
 	if metadata.SetRemoteAddr(conn.LocalAddr()) != nil {
 		return conn
@@ -36,7 +40,7 @@ func (l *loopBackDetector) NewConn(conn C.Conn) C.Conn {
 	})
 }
 
-func (l *loopBackDetector) NewPacketConn(conn C.PacketConn) C.PacketConn {
+func (l *Detector) NewPacketConn(conn C.PacketConn) C.PacketConn {
 	metadata := C.Metadata{}
 	if metadata.SetRemoteAddr(conn.LocalAddr()) != nil {
 		return conn
@@ -51,18 +55,24 @@ func (l *loopBackDetector) NewPacketConn(conn C.PacketConn) C.PacketConn {
 	})
 }
 
-func (l *loopBackDetector) CheckConn(connAddr netip.AddrPort) bool {
+func (l *Detector) CheckConn(metadata *C.Metadata) error {
+	connAddr := metadata.SourceAddrPort()
 	if !connAddr.IsValid() {
-		return false
+		return nil
 	}
-	_, ok := l.connMap.Load(connAddr)
+	if _, ok := l.connMap.Load(connAddr); ok {
-	return ok
+		return fmt.Errorf("%w to: %s", ErrReject, metadata.RemoteAddress())
+	}
+	return nil
 }
 
-func (l *loopBackDetector) CheckPacketConn(connAddr netip.AddrPort) bool {
+func (l *Detector) CheckPacketConn(metadata *C.Metadata) error {
+	connAddr := metadata.SourceAddrPort()
 	if !connAddr.IsValid() {
-		return false
+		return nil
 	}
-	_, ok := l.packetConnMap.Load(connAddr)
+	if _, ok := l.packetConnMap.Load(connAddr); ok {
-	return ok
+		return fmt.Errorf("%w to: %s", ErrReject, metadata.RemoteAddress())
+	}
+	return nil
 }

tunnel/tunnel.go

@@ -12,6 +12,7 @@ import (
 	"time"
 
 	N "github.com/metacubex/mihomo/common/net"
+	"github.com/metacubex/mihomo/component/loopback"
 	"github.com/metacubex/mihomo/component/nat"
 	P "github.com/metacubex/mihomo/component/process"
 	"github.com/metacubex/mihomo/component/resolver"
@@ -694,6 +695,9 @@ func shouldStopRetry(err error) bool {
 	if errors.Is(err, resolver.ErrIPv6Disabled) {
 		return true
 	}
+	if errors.Is(err, loopback.ErrReject) {
+		return true
+	}
 	return false
 }