dns_client: fix crash issue when upstream response delay is lower than 1ms

src/dns_client.c

@@ -3135,11 +3135,13 @@ int dns_client_query(const char *domain, int qtype, dns_client_callback callback
 	}
 
 	pthread_mutex_lock(&client.domain_map_lock);
-	if (list_empty(&client.dns_request_list)) {
-		pthread_cond_signal(&client.run_cond);
-	}
+	if (hash_hashed(&query->domain_node)) {
+		if (list_empty(&client.dns_request_list)) {
+			pthread_cond_signal(&client.run_cond);
+		}
 
-	list_add_tail(&query->dns_request_list, &client.dns_request_list);
+		list_add_tail(&query->dns_request_list, &client.dns_request_list);
+	}
 	pthread_mutex_unlock(&client.domain_map_lock);
 
 	tlog(TLOG_INFO, "send request %s, qtype %d, id %d\n", domain, qtype, query->sid);

src/dns_server.c

@@ -908,7 +908,7 @@ static int _dns_server_reply_udp(struct dns_request *request, struct dns_server_
 	struct iovec iovec[1];
 	struct msghdr msg;
 	struct cmsghdr *cmsg;
-	char msg_control[256];
+	char msg_control[64];
 
 	if (atomic_read(&server.run) == 0 || inpacket == NULL || inpacket_len <= 0) {
 		return -1;
@@ -916,6 +916,7 @@ static int _dns_server_reply_udp(struct dns_request *request, struct dns_server_
 
 	iovec[0].iov_base = inpacket;
 	iovec[0].iov_len = inpacket_len;
+	memset(msg_control, 0, sizeof(msg_control));
 	msg.msg_iov = iovec;
 	msg.msg_iovlen = 1;
 	msg.msg_control = msg_control;