bind9/doc/notes
Matthijs Mekking 2a5e0232ed Fix nonsensical stale TTL values in cache dump
When introducing change 5149, "rndc dumpdb" started to print a line
above a stale RRset, indicating how long the data will be retained.

At that time, I thought it should also be possible to load
a cache from file. But if a TTL has a value of 0 (because it is stale),
stale entries wouldn't be loaded from file. So, I added the
'max-stale-ttl' to TTL values, and adjusted the $DATE accordingly.

Since we actually don't have a "load cache from file" feature, this
is premature and is causing confusion at operators. This commit
changes the 'max-stale-ttl' adjustments.

A check in the serve-stale system test is added for a non-stale
RRset (longttl.example) to make sure the TTL in cache is sensible.

Also, the comment above stale RRsets could have nonsensical
values. A possible reason why this may happen is when the RRset was
marked a stale but the 'max-stale-ttl' has passed (and is actually an
RRset awaiting cleanup). This would lead to the "will be retained"
value to be negative (but since it is stored in an uint32_t, you would
get a nonsensical value (e.g. 4294362497).

To mitigate against this, we now also check if the header is not
ancient. In addition we check if the stale_ttl would be negative, and
if so we set it to 0. Most likely this will not happen because the
header would already have been marked ancient, but there is a possible
race condition where the 'rdh_ttl + serve_stale_ttl' has passed,
but the header has not been checked for staleness.
2021-04-13 09:48:20 +02:00
..
notes-9.17.0.rst update all copyright headers to eliminate the typo 2020-09-14 16:20:40 -07:00
notes-9.17.1.rst update all copyright headers to eliminate the typo 2020-09-14 16:20:40 -07:00
notes-9.17.2.rst update all copyright headers to eliminate the typo 2020-09-14 16:20:40 -07:00
notes-9.17.3.rst Use :rfc:<number> references in release notes 2021-02-17 22:20:24 +01:00
notes-9.17.4.rst update all copyright headers to eliminate the typo 2020-09-14 16:20:40 -07:00
notes-9.17.5.rst Fix 'deprected' typo 2020-09-21 11:26:52 +02:00
notes-9.17.6.rst Prepare release notes for BIND 9.17.6 2020-10-22 08:54:32 +02:00
notes-9.17.7.rst Prepare release notes for BIND 9.17.7 2020-11-26 12:12:17 +01:00
notes-9.17.8.rst Prepare release notes for BIND 9.17.8 2020-12-16 22:05:50 +01:00
notes-9.17.9.rst Use :rfc:<number> references in release notes 2021-02-17 22:20:24 +01:00
notes-9.17.10.rst Prepare release notes for BIND 9.17.10 2021-02-17 22:20:24 +01:00
notes-9.17.11.rst Prepare release notes for BIND 9.17.11 2021-03-18 15:55:11 +01:00
notes-current.rst Fix nonsensical stale TTL values in cache dump 2021-04-13 09:48:20 +02:00