Add clash mode support

route/rule_clash_mode.go

@@ -0,0 +1,33 @@
+package route
+
+import (
+	"strings"
+
+	"github.com/sagernet/sing-box/adapter"
+)
+
+var _ RuleItem = (*ClashModeItem)(nil)
+
+type ClashModeItem struct {
+	router adapter.Router
+	mode   string
+}
+
+func NewClashModeItem(router adapter.Router, mode string) *ClashModeItem {
+	return &ClashModeItem{
+		router: router,
+		mode:   strings.ToLower(mode),
+	}
+}
+
+func (r *ClashModeItem) Match(metadata *adapter.InboundContext) bool {
+	clashServer := r.router.ClashServer()
+	if clashServer == nil {
+		return false
+	}
+	return clashServer.Mode() == r.mode
+}
+
+func (r *ClashModeItem) String() string {
+	return "clash_mode=" + r.mode
+}