Instead of mixing the dns_resolver and dns_validator units directly with
the EDE code, split-out the dns_ede functionality into own separate
compilation unit and hide the implementation details behind abstraction.
Additionally, the EDE codes are directly copied into the ns_client
buffers by passing the EDE context to dns_resolver_createfetch().
This makes the dns_ede implementation simpler to use, although sligtly
more complicated on the inside.
Co-authored-by: Colin Vidal <colin@isc.org>
Co-authored-by: Ondřej Surý <ondrej@isc.org>
(cherry picked from commit 2f8e0edf3b)
Add support for EDE codes 1 (Unsupported DNSKEY Algorithm) and 2
(Unsupported DS Digest Type) which might occurs during DNSSEC
validation in case of unsupported DNSKEY algorithm or DS digest type.
Because DNSSEC internally kicks off various fetches, we need to copy
all encountered extended errors from fetch responses to the fetch
context. Upon an event, the errors from the fetch context are copied
to the client response.
(cherry picked from commit 46a58acdf5)
Extended DNS error mechanism (EDE) enables to have several EDE raised
during a DNS resolution (typically, a DNSSEC query will do multiple
fetches which each of them can have an error). Add support to up to 3
EDE errors in an DNS response. If duplicates occur (two EDEs with the
same code, the extra text is not compared), only the first one will be
part of the DNS answer.
Because the maximum number of EDE is statically fixed, `ns_client_t`
object own a static vector of `DNS_DE_MAX_ERRORS` (instead of a linked
list, for instance). The array can be fully filled (all slots point to
an allocated `dns_ednsopt_t` object) or partially filled (or
empty). In such case, the first NULL slot means there is no more EDE
objects.
(cherry picked from commit 4096f27130)
When answering queries, don't add data to the additional section if
the answer has more than 13 names in the RDATA. This limits the
number of lookups into the database(s) during a single client query,
reducing query processing load.
Also, don't append any additional data to type=ANY queries. The
answer to ANY is already big enough.
(cherry picked from commit a1982cf1bb)
In dns_zone_getdnssecsignstats, dns_zone_getrcvquerystats and
dns_zone_getrequeststats attach to the statistics structure.
(cherry picked from commit fb50a71159)
Add support for Extended DNS Errors (EDE) error 22: No reachable
authority. This occurs when after a timeout delay when the resolver is
trying to query an authority server.
(cherry picked from commit d13e94b930)
Commit amended in order to fix usage of isc_log_write (adding dns_lctx
parameter)
maxlabels is the suffix length that corresponds to the latest
NXDOMAIN response. minlabels is the suffix length that corresponds
to longest found existing name.
(cherry picked from commit 67f31c5046)
Rename check_recursionquota() to acquire_recursionquota(), and
implement a new function called release_recursionquota() to
reverse the action. It helps with decreasing code duplication.
(cherry picked from commit 7bd44a4182)
In two places, after linking the client to the manager's
"recursing-clients" list using the check_recursionquota()
function, the query.c module fails to unlink it on error
paths. Fix the bugs by unlinking the client from the list.
Also make sure that unlinking happens before detaching the
client's handle, as it is the logically correct order, e.g.
in case if it's the last handle and ns__client_reset_cb()
can be called because of the detachment.
(cherry picked from commit 36c4808903)
The 'nodetach' member is a leftover from the times when non-zero
'stale-answer-client-timeout' values were supported, and currently
is always 'false'. Clean up the member and its usage.
(cherry picked from commit b8c068835e)
Query and response log shares the same flags. Move flags logging out of
log_query to share it with log_response. Use buffer instead of snprintf
to fill flags a bit faster.
Signed-off-by: Petr Menšík <pemensik@redhat.com>
(cherry picked from commit e6b19af2dd)
Remove answer flag from log, log instead count of records for each
message section. Include EDNS version and few flags of response. Add
also status of result.
Still does not include body of responses rrset.
(cherry picked from commit 6f879aba65)
Log to the querylog the rcode of a previous query using
the identifier 'response:' to diffenciate queries from
responses.
(cherry picked from commit 5fad79c92f)
Return partial match from dns_db_find/dns_db_find when requested
to short circuit the closest encloser discover process. Most of the
time this will be the actual closest encloser but may not be when
there yet to be committed / cleaned up versions of the zone with
names below the actual closest encloser.
(cherry picked from commit d42ea08f16)
Log canceled queries (e.g. when shutting down a hung fetch)
in DEBUG3 level instead of DEBUG1 which is used for the
"unrecognized" result codes.
(cherry picked from commit 8bb9568467)
MAX_RESTARTS is no longer hard-coded; ns_server_setmaxrestarts()
and dns_client_setmaxrestarts() can now be used to modify the
max-restarts value at runtime. in both cases, the default is 11.
(cherry picked from commit c5588babaf)
the number of steps that can be followed in a CNAME chain
before terminating the lookup has been reduced from 16 to 11.
(this is a hard-coded value, but will be made configurable later.)
(cherry picked from commit 05d78671bb)
Due to the maximum query restart limitation a long CNAME chain
it is cut after 16 queries but named still returns NOERROR.
Return SERVFAIL instead and the partial answer.
(cherry picked from commit b621f1d88e)
As ns_query_init() cannot fail now, remove the error paths, especially
in ns__client_setup() where we now don't have to care what to do with
the connection if setting up the client could fail. It couldn't fail
even before, but now it's formal.
Clear qctx->zversion when clearing qctx->zrdataset et al in
lib/ns/query.c:qctx_freedata. The uncleared pointer could lead to
an assertion failure if zone data needed to be re-saved which could
happen with stale data support enabled.
The high-water allows administrators to better tune the recursive
clients limit without having to to poll the statistics channel in high
rates to get this number.
An RPZ response's SOA record TTL is set to 1 instead of the SOA TTL,
a boolean value is passed on to query_addsoa, which is supposed to be
a TTL value. I don't see what value is appropriate to be used for
overriding, so we will pass UINT32_MAX.
Use the (1 << N) form for defining the flags, in order to avoid
errors like the one fixed in the previous commit.
Also convert the definitions to an enum, as done in some of our
recent refactoring work.
The DNS_GETDB_STALEFIRST flag is defined as 0x0C, which is the
combination of the DNS_GETDB_PARTIAL (0x04) and the
DNS_GETDB_IGNOREACL (0x08) flags (0x04 | 0x08 == 0x0C) , which is
an obvious error.
All the flags should be power of two, so they don't interfere with
each other. Fix the DNS_GETDB_STALEFIRST flag by setting it to 0x10.
If we are in the process of looking for the A records as part of
dns64 processing and the server-stale timeout triggers, redo the
dns64 changes that had been made to the orignal qctx.
The wrong result value was being saved for resumption with
nxdomain-redirect when performing the fetch. This lead to an assert
when checking that RFC 1918 reverse queries where not leaking to
the global internet.
When serve-stale is enabled and recursive resolution fails, the fallback
to lookup stale data always happens in the cache database. Any
authoritative data is ignored, and only information learned through
recursive resolution is examined.
If there is data in the cache that could lead to an answer, and this can
be just the root delegation, the resolver will iterate further, getting
closer to the answer that can be found by recursing down the root, and
eventually puts the final response in the cache.
Change the fallback to serve-stale to use 'query_getdb()', that finds
out the best matching database for the given query.
when synthesizing a new CNAME, we now check whether the target
matches the query already being processed. if so, we do not
restart the query; this prevents a waste of resources.
Add a trace point that would report when a query gets dropped or slipped
by rate limits. It reports the client IP, the zone, and the RRL result
code.
Co-authored-by: Paul Frieden <pfrieden@yahooinc.com>
The dns_badcache unit had (yet another) own locked hashtable
implementation. Replace the hashtable used by dns_badcache with
lock-free cds_lfht implementation from liburcu.
Under some circumstances when processing a query response - for example,
when it contains a CNAME or DNAME - a query will have to be restarted
from the beginning to look up a new target.
This was previously handled by recursively calling the ns__query_start()
function directly from ns_query_done(). However, performance test data
indicated that chains of CNAMEs could consume quite a bit of time inside
the worker thread, increasing latency for other waiting queries. This
has now been changed so that restarted queries are run asynchronously.
ultimately we want the slab implementation of dns_rdataset to
be usable by more database implementaions than just rbtdb. this
commit moves rdataset_methods to rdataslab.c, renamed
dns_rdataslab_rdatasetmethods.
new database methods have been added: locknode, unlocknode,
addglue, expiredata, and deletedata, allowing external functions to
perform functions that previously required internal access to the
database implementation.
database and heap pointers are now stored in the dns_slabheader object
so that header is the only thing that needs to be passed to some
functions; this will simplify moving functions that process slabheaders
out of rbtdb.c so they can be used by other database implementations.
Colin Vidal
Ondřej SurýandColin Vidal
Andoni Duarte Pintado
Matthijs Mekking
Evan Hunt
Aram Sargsyan
Petr MenšíkandMark Andrews
Aydın Mercan
Michał Kępień
Michal Nowak
Tony FinchandOndřej Surý