/* Request failed, immediately try again with reduced features */
- if (t->current_feature_level <= DNS_SERVER_FEATURE_LEVEL_WORST) {
- /* This was already at the lowest possible feature level? If so, we can't downgrade
- * this transaction anymore, hence let's process the response, and accept the rcode. */
+ if (t->current_feature_level <= DNS_SERVER_FEATURE_LEVEL_UDP) {
+ /* This was already at UDP feature level? If so, it doesn't make sense to downgrade
+ * this transaction anymore, hence let's process the response, and accept the
+ * rcode. Note that we don't retry on TCP, since that's a suitable way to mitigate
+ * packet loss, but is not going to give us better rcodes should we actually have
+ * managed to get them already at UDP level. */
+
log_debug("Server returned error: %s", dns_rcode_to_string(DNS_PACKET_RCODE(p)));
break;
}
return r;
if (t->current_feature_level < DNS_SERVER_FEATURE_LEVEL_UDP)
- return -EAGAIN;
+ return -EAGAIN; /* Sorry, can't do UDP, try TCP! */
if (!dns_server_dnssec_supported(t->server) && dns_type_is_dnssec(t->key->type))
return -EOPNOTSUPP;