* Allow synthesized DNAME TTL=0 to be served from cache within grace period
Addresses doc/TODO: cache TTL=0 packets properly for synthesis.
- rrset_cache_lookup: allow TTL=0 DNAME within 1s grace for synthesis
- synth_dname_msg: support PACKED_RRSET_UPSTREAM_0TTL, return TTL=0 to client
Reduces recursion when authoritative servers return DNAME with TTL=0 (RFC 2308).
Client response still correctly returns TTL=0.
Note: Test with proper TTL=0 DNSSEC RRSIGs omitted - requires ldns-signzone
to generate valid signatures for TTL=0 RRsets.
* Add iter_dname_ttl0.rpl replay test for DNAME TTL=0
Tests signed DNAME with TTL=0 and RRSIG Original TTL=0 (RFC 4034).
Verifies end-to-end handling of TTL=0 DNAME responses.
- Cached messages that reach 0 TTL are considered expired. This prevents
Unbound itself from issuing replies with TTL 0 and possibly causing a
thundering herd at the last second. Upstream replies of TTL 0 still
get the usual pass-through but they are not considered for caching
from Unbound or any of its caching modules.
- 'serve-expired-reply-ttl' is changed and is now capped by the original
TTL value of the record to try and make some sense when replying
with expired records.
- TTL decoding was updated to adhere to RFC8767 section 4 where a set
high-order bit means the value is positive instead of 0.
- Fixes a regression bug with serve-expired that appeared in 1.22.0
and would not allow the iterator to update the cache with
not-yet-validated entries resulting in increased outgoing traffic.
- Treat serve_expired_norec_ttl as a backoff timer for failed updates of expired records.
- Try to use expired answers instead of SERVFAIL if serve-expired is
enabled even without serve-expired-client-timeout.
- Add suggestion to refresh the cached norec_ttl and expired_ttl when a
response cannot update the usable expired entry.
current delegation information be updated in cache. The fix allows
current delegation and validation recursion information to be
updated, but as a consequence no longer has certain expired
information around for later dnssec valid expired responses.
- Fix cache update when serve expired is used in order to not evict
still usable expired records. Modules are forbidden to update the
cache if their answer is DNSSEC unchecked or bogus and a valid
(expired) entry already exists. Bogus replies from the validator are
also discarded in favor of existing (expired) valid replies.
- serve-expired-ttl-reset should try to keep expired records in the
cache in case they are reset.
`harden-unverified-glue`, from Karthik Umashankar (Microsoft).
Enabling this option protects the Unbound resolver against bad
glue, that is unverified out of zone glue, by resolving them.
It uses the records as last resort if there is no other working
glue.
performed, so that with nonzero target-fetch-policy it fetches
forwarder addresses and uses them from cache. Also updated that
delegation point cache fill routines use CDflag for AAAA message
lookups, so that its negative lookup stops a recursion since the
cache uses the bit for disambiguation for dns64 but the recursion
uses CDflag for the AAAA target lookups, so the check correctly
stops a useless recursion by its cache lookup.
up to parent to not cause delegation invalidation because of an
expired child delegation that would never be updated. Most likely to
happen without qname-minimisation. Reported by Roland van Rijswijk-Deij.
- Fix SEGFAULT in load_cache control command.
- Change reason_bogus_str to an explicit NULL-terminated string.
- Fix potential memory leak when discarding a message for referrals and
0 TTL answers.
- Fix reason_bogus initialization in localzone answers.
- reply_info creation in validator is always regional.
query into a large number of queries directed to a target.
- CVE-2020-12663 Malformed answers from upstream name servers can be
used to make Unbound unresponsive.
- Added serve-stale functionality as described in
draft-ietf-dnsop-serve-stale-10. `serve-expired-*` options can be used
to configure the behavior.
- Updated cachedb to honor `serve-expired-ttl`; Fixes#107.
- Renamed statistic `num.zero_ttl` to `num.expired` as expired replies
come with a configurable TTL value (`serve-expired-reply-ttl`).
- Fixed stats when replying with cached, cname-aliased records.
- Added missing default values for redis cachedb backend.
answers.
- For harden-below-nxdomain: do not consider a name to be non-exitent when
message contains a CNAME record.
git-svn-id: file:///svn/unbound/trunk@5174 be551aaa-1e26-0410-a405-d3ace91eadb9
deny-any: yes in unbound.conf. This responds with an empty message
to queries of type ANY.
git-svn-id: file:///svn/unbound/trunk@4949 be551aaa-1e26-0410-a405-d3ace91eadb9
W.C.A. Wijngaards