Feature: support domain in fallback filter (#964)

dns/filters.go

@@ -4,9 +4,10 @@ import (
 	"net"
 
 	"github.com/Dreamacro/clash/component/mmdb"
+	"github.com/Dreamacro/clash/component/trie"
 )
 
-type fallbackFilter interface {
+type fallbackIPFilter interface {
 	Match(net.IP) bool
 }
 
@@ -24,3 +25,22 @@ type ipnetFilter struct {
 func (inf *ipnetFilter) Match(ip net.IP) bool {
 	return inf.ipnet.Contains(ip)
 }
+
+type fallbackDomainFilter interface {
+	Match(domain string) bool
+}
+type domainFilter struct {
+	tree *trie.DomainTrie
+}
+
+func NewDomainFilter(domains []string) *domainFilter {
+	df := domainFilter{tree: trie.New()}
+	for _, domain := range domains {
+		df.tree.Insert(domain, "")
+	}
+	return &df
+}
+
+func (df *domainFilter) Match(domain string) bool {
+	return df.tree.Search(domain) != nil
+}