Fix multiplex client dialer context

adapter/inbound.go

@@ -96,3 +96,12 @@ func ExtendContext(ctx context.Context) (context.Context, *InboundContext) {
 	}
 	return WithContext(ctx, &newMetadata), &newMetadata
 }
+
+func OverrideContext(ctx context.Context) context.Context {
+	if metadata := ContextFrom(ctx); metadata != nil {
+		var newMetadata InboundContext
+		newMetadata = *metadata
+		return WithContext(ctx, &newMetadata)
+	}
+	return ctx
+}

common/mux/client.go

@@ -1,11 +1,16 @@
 package mux
 
 import (
+	"context"
+	"net"
+
+	"github.com/sagernet/sing-box/adapter"
 	C "github.com/sagernet/sing-box/constant"
 	"github.com/sagernet/sing-box/option"
 	"github.com/sagernet/sing-mux"
 	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"
 )
 
@@ -30,7 +35,7 @@ func NewClientWithOptions(dialer N.Dialer, logger logger.Logger, options option.
 		}
 	}
 	return mux.NewClient(mux.Options{
-		Dialer:         dialer,
+		Dialer:         &clientDialer{dialer},
 		Logger:         logger,
 		Protocol:       options.Protocol,
 		MaxConnections: options.MaxConnections,
@@ -40,3 +45,15 @@ func NewClientWithOptions(dialer N.Dialer, logger logger.Logger, options option.
 		Brutal:         brutalOptions,
 	})
 }
+
+type clientDialer struct {
+	N.Dialer
+}
+
+func (d *clientDialer) DialContext(ctx context.Context, network string, destination M.Socksaddr) (net.Conn, error) {
+	return d.Dialer.DialContext(adapter.OverrideContext(ctx), network, destination)
+}
+
+func (d *clientDialer) ListenPacket(ctx context.Context, destination M.Socksaddr) (net.PacketConn, error) {
+	return d.Dialer.ListenPacket(adapter.OverrideContext(ctx), destination)
+}