Improve: add DOMAIN rule

rules/domian.go

@@ -0,0 +1,36 @@
+package rules
+
+import (
+	C "github.com/Dreamacro/clash/constant"
+)
+
+type Domain struct {
+	domain  string
+	adapter string
+}
+
+func (d *Domain) RuleType() C.RuleType {
+	return C.Domain
+}
+
+func (d *Domain) IsMatch(addr *C.Addr) bool {
+	if addr.AddrType != C.AtypDomainName {
+		return false
+	}
+	return addr.Host == d.domain
+}
+
+func (d *Domain) Adapter() string {
+	return d.adapter
+}
+
+func (d *Domain) Payload() string {
+	return d.domain
+}
+
+func NewDomain(domain string, adapter string) *Domain {
+	return &Domain{
+		domain:  domain,
+		adapter: adapter,
+	}
+}