Add ping support for WireGuard endpoint

route/route.go

@@ -18,6 +18,7 @@ import (
 	"github.com/sagernet/sing-box/option"
 	"github.com/sagernet/sing-box/route/rule"
 	"github.com/sagernet/sing-mux"
+	"github.com/sagernet/sing-tun"
 	"github.com/sagernet/sing-vmess"
 	"github.com/sagernet/sing/common"
 	"github.com/sagernet/sing/common/buf"
@@ -271,19 +272,36 @@ func (r *Router) routePacketConnection(ctx context.Context, conn N.PacketConn, m
 	return nil
 }
 
-func (r *Router) PreMatch(metadata adapter.InboundContext) error {
+func (r *Router) PreMatch(metadata adapter.InboundContext, routeContext tun.DirectRouteContext) (tun.DirectRouteDestination, error) {
 	selectedRule, _, _, _, err := r.matchRule(r.ctx, &metadata, true, nil, nil)
 	if err != nil {
-		return err
+		return nil, err
 	}
 	if selectedRule == nil {
-		return nil
+		defaultOutbound := r.outbound.Default()
+		if !common.Contains(defaultOutbound.Network(), metadata.Network) {
+			return nil, E.New(metadata.Network, " is not supported by default outbound: ", defaultOutbound.Tag())
+		}
+		return defaultOutbound.(adapter.DirectRouteOutbound).NewDirectRouteConnection(metadata, routeContext)
 	}
-	rejectAction, isReject := selectedRule.Action().(*rule.RuleActionReject)
-	if !isReject {
-		return nil
+	switch action := selectedRule.Action().(type) {
+	case *rule.RuleActionReject:
+		return nil, action.Error(context.Background())
+	case *rule.RuleActionRoute:
+		if routeContext == nil {
+			return nil, nil
+		}
+		outbound, loaded := r.outbound.Outbound(action.Outbound)
+		if !loaded {
+			return nil, E.New("outbound not found: ", action.Outbound)
+		}
+		if !common.Contains(outbound.Network(), metadata.Network) {
+			return nil, E.New(metadata.Network, " is not supported by outbound: ", action.Outbound)
+		}
+		return outbound.(adapter.DirectRouteOutbound).NewDirectRouteConnection(metadata, routeContext)
+	default:
+		return nil, nil
 	}
-	return rejectAction.Error(context.Background())
 }
 
 func (r *Router) matchRule(