DNS: Do not hit cache if encounted err (#3784)

app/dns/nameserver_doh.go

@@ -365,7 +365,7 @@ func (s *DoHNameServer) QueryIP(ctx context.Context, domain string, clientIP net
 		errors.LogDebug(ctx, "DNS cache is disabled. Querying IP for ", domain, " at ", s.name)
 	} else {
 		ips, err := s.findIPsForDomain(fqdn, option)
-		if err != errRecordNotFound {
+		if err == nil || err == dns_feature.ErrEmptyResponse {
 			errors.LogDebugInner(ctx, err, s.name, " cache HIT ", domain, " -> ", ips)
 			log.Record(&log.DNSLog{Server: s.name, Domain: domain, Result: ips, Status: log.DNSCacheHit, Elapsed: 0, Error: err})
 			return ips, err

app/dns/nameserver_quic.go

@@ -300,7 +300,7 @@ func (s *QUICNameServer) QueryIP(ctx context.Context, domain string, clientIP ne
 		errors.LogDebug(ctx, "DNS cache is disabled. Querying IP for ", domain, " at ", s.name)
 	} else {
 		ips, err := s.findIPsForDomain(fqdn, option)
-		if err != errRecordNotFound {
+		if err == nil || err == dns_feature.ErrEmptyResponse {
 			errors.LogDebugInner(ctx, err, s.name, " cache HIT ", domain, " -> ", ips)
 			log.Record(&log.DNSLog{Server: s.name, Domain: domain, Result: ips, Status: log.DNSCacheHit, Elapsed: 0, Error: err})
 			return ips, err

app/dns/nameserver_tcp.go

@@ -323,7 +323,7 @@ func (s *TCPNameServer) QueryIP(ctx context.Context, domain string, clientIP net
 		errors.LogDebug(ctx, "DNS cache is disabled. Querying IP for ", domain, " at ", s.name)
 	} else {
 		ips, err := s.findIPsForDomain(fqdn, option)
-		if err != errRecordNotFound {
+		if err == nil || err == dns_feature.ErrEmptyResponse {
 			errors.LogDebugInner(ctx, err, s.name, " cache HIT ", domain, " -> ", ips)
 			log.Record(&log.DNSLog{Server: s.name, Domain: domain, Result: ips, Status: log.DNSCacheHit, Elapsed: 0, Error: err})
 			return ips, err

app/dns/nameserver_udp.go

@@ -250,7 +250,7 @@ func (s *ClassicNameServer) QueryIP(ctx context.Context, domain string, clientIP
 		errors.LogDebug(ctx, "DNS cache is disabled. Querying IP for ", domain, " at ", s.name)
 	} else {
 		ips, err := s.findIPsForDomain(fqdn, option)
-		if err != errRecordNotFound {
+		if err == nil || err == dns_feature.ErrEmptyResponse {
 			errors.LogDebugInner(ctx, err, s.name, " cache HIT ", domain, " -> ", ips)
 			log.Record(&log.DNSLog{Server: s.name, Domain: domain, Result: ips, Status: log.DNSCacheHit, Elapsed: 0, Error: err})
 			return ips, err