Fix rule_set_ip_cidr_accept_empty not working

dns/client.go

@@ -240,8 +240,10 @@ func (c *Client) Exchange(ctx context.Context, transport adapter.DNSTransport, m
 	if responseChecker != nil {
 		var rejected bool
 		// TODO: add accept_any rule and support to check response instead of addresses
-		if response.Rcode != dns.RcodeSuccess || len(response.Answer) == 0 {
+		if response.Rcode != dns.RcodeSuccess && response.Rcode != dns.RcodeNameError {
 			rejected = true
+		} else if len(response.Answer) == 0 {
+			rejected = !responseChecker(nil)
 		} else {
 			rejected = !responseChecker(MessageToAddresses(response))
 		}

dns/router.go

@@ -273,13 +273,7 @@ func (r *Router) Exchange(ctx context.Context, message *mDNS.Msg, options adapte
 					return action.Response(message), nil
 				}
 			}
-			var responseCheck func(responseAddrs []netip.Addr) bool
-			if rule != nil && rule.WithAddressLimit() {
-				responseCheck = func(responseAddrs []netip.Addr) bool {
-					metadata.DestinationAddresses = responseAddrs
-					return rule.MatchAddressLimit(metadata)
-				}
-			}
+			responseCheck := addressLimitResponseCheck(rule, metadata)
 			if dnsOptions.Strategy == C.DomainStrategyAsIS {
 				dnsOptions.Strategy = r.defaultDomainStrategy
 			}
@@ -395,13 +389,7 @@ func (r *Router) Lookup(ctx context.Context, domain string, options adapter.DNSQ
 					goto response
 				}
 			}
-			var responseCheck func(responseAddrs []netip.Addr) bool
-			if rule != nil && rule.WithAddressLimit() {
-				responseCheck = func(responseAddrs []netip.Addr) bool {
-					metadata.DestinationAddresses = responseAddrs
-					return rule.MatchAddressLimit(metadata)
-				}
-			}
+			responseCheck := addressLimitResponseCheck(rule, metadata)
 			if dnsOptions.Strategy == C.DomainStrategyAsIS {
 				dnsOptions.Strategy = r.defaultDomainStrategy
 			}
@@ -429,6 +417,18 @@ func isAddressQuery(message *mDNS.Msg) bool {
 	return false
 }
 
+func addressLimitResponseCheck(rule adapter.DNSRule, metadata *adapter.InboundContext) func(responseAddrs []netip.Addr) bool {
+	if rule == nil || !rule.WithAddressLimit() {
+		return nil
+	}
+	responseMetadata := *metadata
+	return func(responseAddrs []netip.Addr) bool {
+		checkMetadata := responseMetadata
+		checkMetadata.DestinationAddresses = responseAddrs
+		return rule.MatchAddressLimit(&checkMetadata)
+	}
+}
+
 func (r *Router) ClearCache() {
 	r.client.ClearCache()
 	if r.platformInterface != nil {