Matthijs Mekking d939d2ecde Only refresh RRset once ... Don't attempt to resolve DNS responses for intermediate results. This may create multiple refreshes and can cause a crash. One scenario is where for the query there is a CNAME and canonical answer in cache that are both stale. This will trigger a refresh of the RRsets because we encountered stale data and we prioritized it over the lookup. It will trigger a refresh of both RRsets. When we start recursing, it will detect a recursion loop because the recursion parameters will eventually be the same. In 'dns_resolver_destroyfetch' the sanity check fails, one of the callers did not get its event back before trying to destroy the fetch. Move the call to 'query_refresh_rrset' to 'ns_query_done', so that it is only called once per client request. Another scenario is where for the query there is a stale CNAME in the cache that points to a record that is also in cache but not stale. This will trigger a refresh of the RRset (because we encountered stale data and we prioritized it over the lookup). We mark RRsets that we add to the message with DNS_RDATASETATTR_STALE_ADDED to prevent adding a duplicate RRset when a stale lookup and a normal lookup conflict with each other. However, the other non-stale RRset when following a CNAME chain will be added to the message without setting that attribute, because it is not stale. This is a variant of the bug in #2594. The fix covered the same crash but for stale-answer-client-timeout > 0. Fix this by clearing all RRsets from the message before refreshing. This requires the refresh to happen after the query is send back to the client.		2022-09-08 11:24:37 +02:00
..
ns	Only refresh RRset once	2022-09-08 11:24:37 +02:00
.clang-format	Add separate .clang-format files for headers	2020-02-14 09:31:05 +01:00