depending on how the QP trie is traversed during a lookup, it is
possible for a search to terminate on a leaf which is a partial
match, without that leaf being added to the chain. to ensure the
chain is correct in this case, when a partial match condition is
detected via qpkey_compare(), we will call add_link() again, just
in case. (add_link() will check for a duplicated node, so it will
be harmless if it was already done.)
This was generated from dnsperf queryfile with following script:
#!/usr/bin/env python3
names = {}
import sys
i = 0
for line in iter(sys.stdin.readline, ''):
name = line.rstrip('\n')
if not name in names:
names[name] = line
print(f"{i},{name}")
i += 1
if i >= 1024*1024:
break
The name_match() was errorneously converting struct item into dns_name
pointer. Correctly retype void *node to struct item * first and then
use item.fixed.name to pass the name to dns_name_equal() function.
The load_names benchmark expected the input CSV with domains would fill
the whole item array and it would crash when the number of lines would
be less than that.
Fix the expectations by using the real number or lines read to calculate
the array start and end position for each benchmark thread.
dns_qp_findname_ancestor() now takes an optional 'predecessor'
parameter, which if non-NULL is updated to contain the DNSSEC
predecessor of the name searched for. this is done by constructing
an iterator stack while carrying out the search, so it can be used
to step backward if needed.
since dns_qp_findname_ancestor() can now return a chain object, it is no
longer necessary to provide a _NOEXACT search option. if we want to look
up the closest ancestor of a name, we can just do a normal search, and
if successful, retrieve the second-to-last node from the QP chain.
this makes ancestor lookups slightly more complicated for the caller,
but allows us to simplify the code in dns_qp_findname_ancestor(), making
it easier to ensure correctness. this was a fairly rare use case:
outside of unit tests, DNS_QPFIND_NOEXACT was only used in the zone
table, which has now been updated to use the QP chain. the equivalent
RBT feature is only used by the resolver for cache lookups of 'atparent'
types (i.e, DS records).
- make iterators reversible: refactor dns_qpiter_next() and add a new
dns_qpiter_prev() function to support iterating both forwards and
backwards through a QP trie.
- added a 'name' parameter to dns_qpiter_next() (as well as _prev())
to make it easier to retrieve the nodename while iterating, without
having to construct it from pointer value data.
- the helper functions for accessing twigs beneath a branch
(branch_twig_pos(), branch_twig_ptr(), etc) were somewhat confusing
to read, since several of them were implemented by calling other
helper functions. they now all show what they're really doing.
- branch_twigs_vector() has been renamed to simply branch_twigs().
- revised some unrelated comments in qp_p.h for clarity.
dns_qp_findname_ancestor() now takes an optional 'chain' parameter;
if set, the dns_qpchain object it points to will be updated with an
array of pointers to the populated nodes between the tree root and the
requested name. the number of nodes in the chain can then be accessed
using dns_qpchain_length() and the individual nodes using
dns_qpchain_node().
add a 'foundname' parameter to dns_qp_findname_ancestor(),
and use it to set the found name in dns_nametree.
this required adding a dns_qpkey_toname() function; that was
done by moving qp_test_keytoname() from the test library to qp.c.
added some more test cases and fixed bugs with the handling of
relative and empty names.
this loads a file containing DNS names and measures the time it takes to:
1) iterate it,
2) look up each name with dns_qp_getname()
3) look up each name with dns_qp_findname_ancestor()
4) look up a modified name based on the name, to check performance
when the name is not found.
the refactoring of isc_job_run() and isc_async_run() in 9.19.12
intefered with the way the qpmulti benchmark uses uv_idle.
it has now been modified to use isc_job/isc_async instead.
Instead of creating new memory pools for each new dns_message, change
dns_message_create() method to optionally accept externally created
dns_fixedname_t and dns_rdataset_t memory pools. This allows us to
preallocate the memory pools in ns_client and dns_resolver units for the
lifetime of dns_resolver_t and ns_clientmgr_t.
When isc_hashmap_iter_delcurrent_next calls hashmap_delete_node
nodes from the front of the table could be added to the end of
the table resulting in them being returned twice. Detect when
this is happening and prevent those nodes being returned twice
buy reducing the effective size of the table by one each time
it happens.
Reusing TCP connections with dns_dispatch_gettcp() used linear linked
list to lookup existing outgoing TCP connections that could be reused.
Replace the linked list with per-loop cds_lfht hashtable to speedup the
lookups. We use cds_lfht because it allows non-unique node insertion
that we need to check for dispatches in different connection states.
Instead of high number of dispatches (4 * named_g_udpdisp)[1], make the
dispatches bound to threads and make dns_dispatchset_t create a dispatch
for each thread (event loop).
This required couple of other changes:
1. The dns_dispatch_createudp() must be called on loop, so the isc_tid()
is already initialized - changes to nsupdate and mdig were required.
2. The dns_requestmgr had only a single dispatch per v4 and v6. Instead
of using single dispatch, use dns_dispatchset_t for each protocol -
this is same as dns_resolver.
Refactor isc_hashmap to allow custom matching functions. This allows us
to have better tailored keys that don't require fixed uint8_t arrays,
but can be composed of more fields from the stored data structure.
When inserting items into hashtables (hashmaps), we might have a
fragmented key (as an example we might want to hash DNS name + class +
type). We either need to construct continuous key in the memory and
then hash it en bloc, or incremental hashing is required.
This incremental version of SipHash 2-4 algorithm is the first building
block.
As SipHash 2-4 is often used in the hot paths, I've turned the
implementation into header-only version in the process.
instead of allowing a NULL nametree in dns_nametree_covered(),
require nametree to exist, and ensure that the nametrees defined
for view and resolver objects are always created.
name trees can now also hold trees of counters. each time a name
dns_nametree_add() is called with a given name, the counter for that
name is incremented; the name is not deleted until dns_nametree_delete()
is called the same number of times.
this is meant to be used for synth-from-dnssec, which is incremented for
each key defined at a name, and decremented when a key is removed, the
name must continue to exist until the number of keys has reached zero.
name trees can now hold either boolean values or bit fields. the
type is selected when the name tree is created.
the behavior of dns_nametree_add() differs slightly beteween the types:
in a boolean tree adding an existing name will return ISC_R_EXISTS,
but in a bitfield tree it simply sets the specified bit in the bitfield
and returns ISC_R_SUCCESS.
this is a QP trie of boolean values to indicate whether a name is
included in or excluded from some policy. this can be used for
synth-from-dnssec, deny-answer-aliases, etc.
Use the new isc_mem_c*() calloc-like API for allocations that are
zeroed.
In turn, this also fixes couple of incorrect usage of the ISC_MEM_ZERO
for structures that need to be zeroed explicitly.
There are few places where isc_mem_cput() is used on structures with a
flexible member (or similar).
The resolution of the uv_hrtime() function is bigger than the
intervals used in the timers, which can result in an unexpected
difference between the start_time and stop_time variables.
Use isc_loop_now(), which is based on uv_now() and has the same
milliseconds resolution as the functions in the uv_timer_t API.
Also fix a couple wrong numbers in the comments.
Add tracing probes to isc_job unit:
* libisc:job_cb_before - before the job callback is called
* libisc:job_cb_after - after the job callback is called
This adds support for User Statically Defined Tracing (USDT). On
Linux, this uses the header from SystemTap and dtrace utility, but the
support is universal as long as dtrace is available.
Also add the required infrastructure to add probes to libisc, libdns and
libns libraries, where most of the probes will be.
The dns_dispatchmgr object was only set in the dns_view object making it
prone to use-after-free in the dns_xfrin unit when shutting down named.
Remove dns_view_setdispatchmgr() and optionally pass the dispatchmgr
directly to dns_view_create() when it is attached and not just assigned,
so the dns_dispatchmgr doesn't cease to exist too early.
The dns_view_getdnsdispatchmgr() is now protected by the RCU lock, the
dispatchmgr reference is incremented, so the caller needs to detach from
it, and the function can return NULL in case the dns_view has been
already shut down.
replace the red-black tree used by the negative trust anchor table
with a QP trie.
because of this change, dns_ntatable_init() can no longer fail, and
neither can dns_view_initntatable(). these functions have both been
changed to type void.
this function finds the closest matching ancestor, but the function
name could be read to imply that it returns the direct parent node;
this commit suggests a slightly less misleading name.
Make the `pval_r` and `ival_r` out arguments optional.
Add `pval_r` and `ival_r` out arguments to `dns_qp_deletekey()`
and `dns_qp_deletename()`, to return the deleted leaf.
Add simple rwlock unit test and rwlock benchmark. The benchmark
compares the pthread rwlock with isc rwlock implementation, so it's
mainly useful when developing a new isc rwlock implementation.
The load-names benchmark was originally only measuring single thread
performance of the data structures. As this is not how those are used
in the real life, it was refactored to be multi-threaded with proper
protections in place (rwlock for ht, hashmap and rbt; transactions for
qp).
The qp test has been extended to see effect of the dns_qp_compact() and
rcu_barrier() on the overall speed and memory consumption.
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.
