removed references in code comments, doc/dev documentation, etc, to
isc_task, isc_timer_reset(), and isc_timertype_inactive. also removed a
coccinelle patch related to isc_timer_reset() that was no longer needed.
as there is no further use of isc_task in BIND, this commit removes
it, along with isc_taskmgr, isc_event, and all other related types.
functions that accepted taskmgr as a parameter have been cleaned up.
as a result of this change, some functions can no longer fail, so
they've been changed to type void, and their callers have been
updated accordingly.
the tasks table has been removed from the statistics channel and
the stats version has been updated. dns_dyndbctx has been changed
to reference the loopmgr instead of taskmgr, and DNS_DYNDB_VERSION
has been udpated as well.
callback events from dns_resolver_createfetch() are now posted
using isc_async_run.
other modules which called the resolver and maintained task/taskmgr
objects for this purpose have been cleaned up.
The callbacks from dns_abd_createfind() are now posted using
isc_async_run() instead of isc_task_send(). ADB event types
have been replaced with a new dns_adbstatus_t type which is
included as find->status.
(The ADB still uses a task for dns_resolver_createfetch().)
dns_request_create() and _createraw() now take a 'loop' parameter
and run the callback event on the specified loop.
as the task manager is no longer used, it has been removed from
the dns_requestmgr structure. the dns_resolver_taskmgr() function
is also no longer used and has been removed.
This changes the internal isc_rwlock implementation to:
Irina Calciu, Dave Dice, Yossi Lev, Victor Luchangco, Virendra
J. Marathe, and Nir Shavit. 2013. NUMA-aware reader-writer locks.
SIGPLAN Not. 48, 8 (August 2013), 157–166.
DOI:https://doi.org/10.1145/2517327.24425
(The full article available from:
http://mcg.cs.tau.ac.il/papers/ppopp2013-rwlocks.pdf)
The implementation is based on the The Writer-Preference Lock (C-RW-WP)
variant (see the 3.4 section of the paper for the rationale).
The implemented algorithm has been modified for simplicity and for usage
patterns in rbtdb.c.
The changes compared to the original algorithm:
* We haven't implemented the cohort locks because that would require a
knowledge of NUMA nodes, instead a simple atomic_bool is used as
synchronization point for writer lock.
* The per-thread reader counters are not being used - this would
require the internal thread id (isc_tid_v) to be always initialized,
even in the utilities; the change has a slight performance penalty,
so we might revisit this change in the future. However, this change
also saves a lot of memory, because cache-line aligned counters were
used, so on 32-core machine, the rwlock would be 4096+ bytes big.
* The readers use a writer_barrier that will raise after a while when
readers lock can't be acquired to prevent readers starvation.
* Separate ingress and egress readers counters queues to reduce both
inter and intra-thread contention.
When there are multiple managed trust anchors we need to know the
name of the trust anchor that is failing. Extend the error message
to include the trust anchor name.
it was possible for a managed trust anchor needing to send a key
refresh query to be unable to do so because an authoritative zone
was not yet loaded. this has been corrected by delaying the
synchronization of managed-keys zones until after all zones are
loaded.
the rate limter now uses loop callbacks rather than task events.
the API for isc_ratelimiter_enqueue() has been changed; we now pass
in a loop, a callback function and a callback argument, and
receive back a rate limiter event object (isc_rlevent_t). it
is no longer necessary for the caller to allocate the event.
the callback argument needs to include a pointer to the rlevent
object so that it can be freed using isc_rlevent_free(), or by
dequeueing.
Both receive_secure_serial() and setnsec3param() run on the same zone
loop, therefore they are serialized. Remove the mechanism to enqueue
the nsec3param and secure serial updates in case one of them is
running (as they can not) and replace it with sanity check.
Previously, the zone loading and dumping was effectively serialized by
the dns_io_t mechanism. In theory, more IO operations could be run in
parallel, but the zone manager .iolimit was set to 1 and never increased
as dns_zonemgr_setiolimit() was never ever called.
As the dns_master asynchronous load and dump was already offloaded to
non-worker threads with isc_work mechanism, drop the whole dns_io_t
and just rely on the isc_work to do the load and dump scheduling.
It is allowed to point parental-agents to a resolver. Therefore, the
RD bit should be set on requests.
Upon receiving a DS response, ensure that the message has either the
AA or the RA bit set.
Detaching the views in the zone_shutdown() could lead to
lock-order-inversion between adb->namelocks[bucket], adb->lock,
view->lock and zone->lock. Detach the views outside of the section that
zone-locked.
The .view (and possibly .prev_view) would be kept attached to the
removed zone until the zone is fully removed from the memory in
zone_free(). If this process is delayed because server is busy
something else like doing constant `rndc reconfig`, it could take
seconds to detach the view, possibly keeping multiple dead views in the
memory. This could quickly lead to a massive memory bloat.
Release the views early in the zone_shutdown() call, and don't wait
until the zone is freed.
DSCP has not been fully working since the network manager was
introduced in 9.16, and has been completely broken since 9.18.
This seems to have caused very few difficulties for anyone,
so we have now marked it as obsolete and removed the
implementation.
To ensure that old config files don't fail, the code to parse
dscp key-value pairs is still present, but a warning is logged
that the feature is obsolete and should not be used. Nothing is
done with configured values, and there is no longer any
range checking.
The dns_zonemgr_releasezone() function makes a decision to destroy
'zmgr' (based on its references count, after decreasing it) inside
a lock, and then destroys the object outside of the lock.
This causes a race with dns_zonemgr_detach(), which could destroy
the object in the meantime.
Change dns_zonemgr_releasezone() to detach from 'zmgr' and destroy
the object (if needed) using dns_zonemgr_detach(), outside of the
lock.
Since dns_master_dump() can no longer return DNS_R_CONTINUE,
the error recovery code in synchronous calls to zone_dump() had
branches that could no longer be reached. This has been cleaned
up by using a boolean variable to determine whether the write
is asynchronous rather than depending on the result code.
Remove parsing the configuration options 'alt-transfer-source',
'alt-transfer-source-v6', and 'use-alt-transfer-source', and remove
the corresponding code that implements the feature.
Use the configured 'source' and 'source-v6' when initiating a zone
transfer, sending a notify, or when checking for the DS. Remove the
special code for using alternate transfer sources.
Update some system tests to use the new configuration and make sure
the tests still work.
Instead of relying on hash table search when using the keys, implement a
proper reference counting in dns_keyfileio_t objects, and attach/detach
the objects to the zone.
Due to off-by-one error in zonemgr_keymgmt_delete, unused key file IO
lock objects were never freed and they were kept until the server
shutdown. Adjust the returned value by -1 to accomodate the fact that
the atomic_fetch_*() functions return the value before the operation and
not current value after the operation.
dns_db_updatenotify_unregister needed to be called earlier to ensure
that listener->onupdate_arg always points to a valid object. The
existing lazy cleanup in rbtdb_free did not ensure that.
The mechanism for associating a worker task to a database now
uses loops rather than tasks.
For this reason, the parameters to dns_cache_create() have been
updated to take a loop manager rather than a task manager.
The "final reference detached" message was meant to be DEBUG(1), but was
instead kept at INFO level. Move it to the DEBUG(1) logging level, so
it's not printed under normal operations.
Despite the RFC says that the NSEC3PARAM is not something that is
intended for the resolver to be cached, and thus the TTL of 0 is most
logical, a zero TTL RRset can be abused by bad actors.
Change the default to SOA MINIMUM.
The zone_refreshkeys() could run before the zone_shutdown(), but after
the last .erefs has been "detached" causing assertion failure when doing
dns_zone_attach(). Remove the use of .erefs (dns_zone_attach/detach)
and replace it with using the .irefs and additional checks whether the
zone is exiting in the callbacks.
There was an exception for dnssec-policy that allowed DNSSEC in the
unsigned version of the zone. This however causes a crash if the
zone switches from dynamic to inline-signing in the case of NSEC3,
because we are now trying to add an NSEC3 record to a non-NSEC3 node.
This is because BIND expects none of the records in the unsigned
version of the zone to be NSEC3.
Remove the exception for dnssec-policy when copying non DNSSEC
records, but do allow for DNSKEY as this may be a published DNSKEY
from a different provider.
When named starts it creates an empty KEYDATA record in the managed-keys
zone as a placeholder, then schedules a key refresh. If key refresh
fails for some reason (e.g. connectivity problems), named will load the
placeholder key into secroots as a trusted key during the next startup,
which will break the chain of trust, and named will never recover from
that state until managed-keys.bind and managed-keys.bind.jnl files are
manually deleted before (re)starting named again.
Before calling load_secroots(), check that we are not dealing with a
placeholder.
Because dns_resolver_createfetch() locks the view, it was necessary
to unlock the zone in zone_refreshkeys() before calling it in order
to maintain the lock order, and relock afterward. this permitted a race
with dns_zone_synckeyzone().
This commit moves the call to dns_resolver_createfetch() into a separate
function which is called asynchronously after the zone has been
unlocked.
The keyfetch object now attaches to the zone to ensure that
it won't be shut down before the asynchronous call completes.
This necessitated refactoring dns_zone_detach() so it always runs
unlocked. For managed zones it now schedules zone_shutdown() to
run asynchronously, and for unmanaged zones, it requires the last
dns_zone_detach() to be run without loopmgr running.
Instead of doing incremental zone loading with fixed quantum - 100
loaded lines per event, move the zone loading process to the offloaded
libuv threads using isc_work_enqueue() API.
This has the advantage that the thread scheduling is given back to the
operating system that understands blocking operations, and the zone
loading operation doesn't block the networking threads directly.
Incremental file loads now use loopmgr events instead of task events.
The dns_master_loadstreaminc(), _loadbufferinc(), _loadlexer() and
_loadlexerinc() functions were not used in BIND, and have been removed.
