Refactor: A faster DomainMatcher implementation (#348)

Co-authored-by: DarthVader <61409963+darsvador@users.noreply.github.com>

infra/conf/router.go

@@ -98,6 +98,8 @@ type RouterRule struct {
 	Type        string `json:"type"`
 	OutboundTag string `json:"outboundTag"`
 	BalancerTag string `json:"balancerTag"`
+
+	DomainMatcher string `json:"domainMatcher"`
 }
 
 func ParseIP(s string) (*router.CIDR, error) {
@@ -491,6 +493,10 @@ func parseFieldRule(msg json.RawMessage) (*router.RoutingRule, error) {
 		return nil, newError("neither outboundTag nor balancerTag is specified in routing rule")
 	}
 
+	if rawFieldRule.DomainMatcher != "" {
+		rule.DomainMatcher = rawFieldRule.DomainMatcher
+	}
+
 	if rawFieldRule.Domain != nil {
 		for _, domain := range *rawFieldRule.Domain {
 			rules, err := parseDomainRule(domain)