Currently, ns3 in the "mirror" system test sends trust anchor telemetry
queries every second as it is started with "-T tat=1". Given the number
of trust anchors configured on ns3 (9), TAT-related traffic clutters up
log files, hindering troubleshooting efforts. Increase TAT query
interval to 3 seconds in order to alleviate the issue.
Note that the interval chosen cannot be much higher if intermittent test
failures are to be avoided: TAT queries are only sent after the
configured number of seconds passes since resolver startup. Quick
experiments show that even on contemporary hardware, ns3 should be
running for at least 5 seconds before it is first shut down, so a
3-second TAT query interval seems to be a reasonable, future-proof
compromise. Ensure the relevant check is performed before ns3 is first
shut down to emphasize this trade-off and make it more clear by what
time TAT queries are expected to be sent.
When a mirror zone is verified, the 'ignore_kskflag' argument passed to
dns_zoneverify_dnssec() is set to false. This means that in order for
its verification to succeed, a mirror zone needs to have at least one
key with the SEP bit set configured as a trust anchor. This brings no
security benefit and prevents zones signed only using keys without the
SEP bit set from being mirrored, so change the value of the
'ignore_kskflag' argument passed to dns_zoneverify_dnssec() to true.
Use a zone's 'type' field instead of the value of its DNS_ZONEOPT_MIRROR
option for checking whether it is a mirror zone. This makes said zone
option and its associated helper function, dns_zone_mirror(), redundant,
so remove them. Remove a check specific to mirror zones from
named_zone_reusable() since another check in that function ensures that
changing a zone's type prevents it from being reused during
reconfiguration.
Force ns3 to use a constant source address (10.53.0.3) when sending
transfer requests for the "initially-unavailable" zone to prevent
failures of transfers not triggered by bin/tests/system/mirror/tests.sh
from causing fallback to using a source address for which transfers of
that zone are refused throughout the entire "mirror" system test since
that might yield false positives.
Trying to resolve a trust anchor telemetry query for a locally served
zone does not cause upstream queries to be sent as the response is
determined just by consulting local data. Work around this issue by
calling dns_view_findzonecut() first in order to determine the NS RRset
for a given domain name and then passing the zone cut found to
dns_resolver_createfetch().
Note that this change only applies to TAT queries generated by the
resolver itself, not to ones received from downstream resolvers.
Update named_zone_reusable() so that it does not consider a zone to be
eligible for reuse if its old value of the "mirror" option differs from
the new one. This causes "rndc reconfig" to create a new zone structure
whenever the value of the "mirror" option is changed, which ensures that
the previous zone database is not reused and that flags are properly set
in responses sourced from zones whose "mirror" setting was changed at
runtime.
As mirror zone data should be treated the way validated, cached DNS
responses are, it should not be used when responding to clients who are
not allowed cache access. Reuse code responsible for determining cache
database access for evaluating mirror zone access.
If transferring or loading a mirror zone fails, resolution should still
succeed by means of falling back to regular recursive queries.
Currently, though, if a slave zone is present in the zone table and not
loaded, a SERVFAIL response is generated. Thus, mirror zones need
special handling in this regard.
Add a new dns_zt_find() flag, DNS_ZTFIND_MIRROR, and set it every time a
domain name is looked up rather than a zone itself. Handle that flag in
dns_zt_find() in such a way that a mirror zone which is expired or not
yet loaded is ignored when looking up domain names, but still possible
to find when the caller wants to know whether the zone is configured.
This causes a fallback to recursion when mirror zone data is unavailable
without making unloaded mirror zones invisible to code checking a zone's
existence.
Make ns3 mirror the "root" zone from ns1 and query the former for a
properly signed record below the root. Ensure ns1 is not queried during
resolution and that the AD bit is set in the response.
As mirror zone files are verified when they are loaded from disk, verify
journal files as well to ensure invalid data is not used. Reuse the
journals generated during IXFR tests to test this.
Update axfr_commit() so that all incoming versions of a mirror zone
transferred using AXFR are verified before being used. If zone
verification fails, discard the received version of the zone, wait until
the next refresh and retry.
