whenever ncache_adderesult() was called, some preparatory code
was run first; this has now been moved into a single function
negcache() to reduce code duplication.
dns_keytable_issecuredomain() and dns_view_issecuredomain()
previously returned a result code to inform the caller of
unexpected database failures when looking up names in the
keytable and/or NTA table. such failures are not actually
possible. both functions now return a simple bool.
also, dns_view_issecuredomain() now returns false if
view->enablevalidation is false, so the caller no longer
has to check for that.
The default stack sizes varies between operating systems and between
different system libc libraries from 128kB (Alpine Linux with MUSL) to
8M (Linux with glibc). Document the different values used to justify
the value of THREAD_MINSTACKSIZE (currently set to 1MB).
When running the isc_quota unit test with less than usual amount of
RAM (e.g. in a CI for architectures with 32 bits of address space),
the pthread_create() function fails with the "Resource temporarily
unavailable (11):" error code.
Add functions to get and set the thread stack size (if requested),
and use these to set the thread stack size to smaller value in the
isc_quota unit test.
When the zone is configured with a CNAME override policy, also add the
configured EDE code.
When the zone is contains a wildcard CNAME, also add the configured
EDE code.
There is a data race when QP is reclaiming chunks on the call_rcu
threads and it tries to log the number of reclaimed chunks while the
server is shuttingdown. Workaround this by adding rcu_barrier() before
shuttingdown the global log context.
This required couple of internal changes to the isc_mem_debugging.
The isc_mem_debugging is now internal to isc_mem unit and there are
three new functions:
1. isc_mem_setdebugging() can change the debugging setting for an
individual memory context. This is need for the memory contexts used
for OpenSSL, libxml and libuv accounting as recording and tracing
memory is broken there.
2. isc_mem_debugon() / isc_mem_debugoff() can be used to change default
memory debugging flags as well as debugging flags for isc_g_mctx.
Additionally, the memory debugging is inconsistent across the code-base.
For now, we are keeping the existing flags, but three new environment
variables have been added 'ISC_MEM_DEBUGRECORD', 'ISC_MEM_DEBUGTRACE'
and 'ISC_MEM_DEBUGUSAGE' to set the global debugging flags at any
program using the memory contexts.
Instead of having individual memory contexts scattered across different
files and called different names, add a single memory context called
isc_g_mctx that replaces named_g_mctx and various other global memory
contexts in various utilities and tests.
Spurious validation failures were traced back to check_signer looping
over val->sigrdataset directly. Cloning val->sigrdataset prevents
check_signer from interacting with callers that are also looping
over val->sigrdataset.
If a plugin is configured without the extension,
`ns_plugin_expandpath()` automatically take cares of appending the
suffix to the path. The way it works is by checking if a file exists at
the expanded path. If it doesn't, it assumes the plugin path (or name)
doesn't have the extension and append the extension (which is
platform-specific) to the actual path.
There is only a single network manager running on top of the loop
manager (except for tests). Refactor the network manager to be a
singleton (a single instance) and change the unit tests, so that the
shorter read timeouts apply only to a specific handle, not the whole
extra 'connect_nm' network manager instance.
All the applications built on top of the loop manager were required to
create just a single instance of the loop manager. Refactor the loop
manager to not expose this instance to the callers and keep the loop
manager object internal to the isc_loop compilation unit.
This significantly simplifies a number of data structures and calls to
the isc_loop API.
The log message 'shut down hung fetch while resolving' may be confusing
because no detection of hung fetches actually takes place, but rather
the timer on the fetch context expires and the resolver gives up.
Change the log message to actually say that instead of the original
cryptic message about hung fetch.
A serve-stale refresh is similar to a prefetch, the only difference
is when it triggers. Where a prefetch is done when an RRset is about
to expire, a serve-stale refresh is done when the RRset is already
stale.
This means that the check for the stale-refresh window needs to
move into query_stale_refresh(). We need to clear the
DNS_DBFIND_STALEENABLED option at the same places as where we clear
DNS_DBFIND_STALETIMEOUT.
Now that serve-stale refresh acts the same as prefetch, there is no
worry that the same rdataset is added to the message twice. This makes
some code obsolete, specifically where we need to clear rdatasets from
the message.
The beauty and horrors of the C - the compiler properly detects variable
shadowing, but you can freely shadow a standard function 'free()' with
variable called 'free'. And if you reference 'free()' just as 'free'
you get the function pointer which means you can do also pointer
arithmetics, so 'free > 0' is always valid even when you delete the
local variable.
Replace the local variables 'free' with a name that doesn't shadow the
'free()' function to prevent future hard to detect bugs.
dns_qp_lookup was returning ISC_R_NOTFOUND rather than DNS_R_PARTIALMATCH
when there wasn't a parent with a NSEC record in the cache. This was
causing find_coveringnsec to fail rather than returing the covering NSEC.
DNSKEY algorithms RSASHA1 and RSASHA-NSEC3-SHA1 and DS digest type
SHA1 are deprecated. Log when these are present in primary zone
files and when generating new DNSKEYs, DS and CDS records.
Is there a time when new_qp(c|z)node() would not be followed by
assignment of the namespace? No, so let's add the assignment to the
function that creates the node.
Now that we have to code working, rename 'dns_qp_lookup2' back to
'dns_qp_lookup' and adjust all remaining 'dns_qp_lookup' occurrences
to take a space=0 parameter.
For now we only allow DNS_DB_NSEC_* values so it makes sense to change
the type to an enum.
Rename 'denial' to the more intuitive 'space', indicating the namespace
of the keyvalue pair.
The dbiterator can take three modes: full, nsec3only and nonsec3.
Previously, in full mode the dbiterator requires special logic to jump
from one qp-trie to the other. Now everything is in one trie, other
special logic is needed.
The qp-trie is now sorted in such a way that all the normal nodes come
first, followed by NSEC nodes, and finally the NSEC3 nodes. NSEC nodes
are empty nodes and need to be skipped when iterating.
We add an additional auxiliary node to the trie, an NSEC origin, so
we can easily find the point in the trie where we need to continue
iterating.
In preparation to merge the three qp tries (tree, nsec, nsec3) into
one, add the piece of information into the qpkey. This is the most
significant bit of information, so prepend the denial type to the qpkey.
This means we need to pass on the denial type when constructing the
qpkey from a name, or doing a lookup.
Reuse the the DNS_DB_NSEC_* values. Most qp tries in the code we just
pass on 0 (nta, rpz, zt, etc.), because there is no need for denial of
existence, but for qpzone and qpcache we must pass the right value.
Change the code, so that node->nsec no longer can have the value
DNS_DB_NSEC_HAS_NSEC, instead track this in a new attribute 'havensec'.
Since we use node->nsec to convert names to keys, the value MUST be set
before inserting the node into the qp-trie.
Update the fuzzing and unit tests accordingly. This only adds a few
extra test cases, more are needed.
In the qp_test.c we can remove test code for empty keys as this is
no longer possible.
RRset ordering is now an enum inside struct rdataset attributes. This
was done to keep size to of the structure to its original value before
this MR.
I expect zero performance impact but it should be easier to deal with
attributes in debuggers and language servers.
As mentioned in the comments block before the changed code block,
the dropped or slipped responses should be logged in the query
category (or rather query-errors category as done in lib/ns/client.c),
so that requests are not silently lost.
Also fix a couple of errors/typos in the code comments.
The ns_client_t struct is reset and zero-ed out on every query,
but some fields (query, message, manager) are preserved.
We observe two things:
- The sendbuf field is going to be overwritten anyway, there's
no need to zero it out.
- The fields are copied out when the struct is zero-ed out, and
then copied back in. For the query field (which is 896 bytes)
this is very inefficient.
This commit makes the reset more efficient avoiding to unnecessary
zero-ing and copy.
Replace the read-write locked isc_hashmap with lock-free cds_lfht
hashtable and replace the singular LRU tables for ADB names and entries
with a per-thread LRU tables. These changes allowed to remove all the
read-write locking on the names and entries tables.
Instead of having hand crafted attach/detach/destroy functions, replace
them with the standard ISC_REFCOUNT macro. This also have advantage
that delayed netmgr detach (from dns_dispatch) now doesn't cause
assertion failure. This can happen with delayed (call_rcu) shutdown of
dns_adb.
The dns_adb cleaning is little bit muddled as it mixes the "TTL"
based cleaning (.expire_v4 and .expire_v6 for adbname, .expires for
adbentry) with overmem cleaning.
Rewrite the LRU based cleaning to use SIEVE algorithm and to be overmem
cleaning only with a requirement to always cleanup at least 2-times the
size of the newly added entry.
Qpzone employs a locking strategy where rwlocks are grouped into
buckets, and each zone gets 17 buckets.
This strategy is suboptimal in two ways:
- If named is serving a single zone or a zone is the majority of the
traffic, this strategy pretty much guarantees contention when using
more than a dozen threads.
- If named is serving many small zones, it causes substantial memory
usage.
This commit switches the locking to a global table initialized at start
time. This should have three effects:
- Performance should improve in the single zone case, since now we are
selecting from a bigger pool of locks.
- Memory consumption should go down significantly in the many zone
cases.
- Performance should not degrade substantially in the many zone cases.
The reason for this is that, while we could have substantially more
zones than locks, we can query/edit only O(num threads) at the same
time. So by making the global table much bigger than the expected
number of threads, we can limit contention.
In the current implementation, the resigning heap is part of the zone
database. This leads to a cycle, as the database has a reference to its
nodes, but each node needs a reference to the database.
This MR splits the resigning heap into its own separate struct, in order
to help breaking the cycle.
Recovering the node lock from a pointer to the header and a pointer to
the db is a common operation. This commit abstracts it away into a
function, so that the node lock selection logic may be modified more
easily.
Print optionally a bit more details not passed to event in case
dns_view_findzonecut returns unexpected result. Result would be
visible later in foundevent, but found fname would be lost. Print it
into the log.
When authoritative zone is loaded when query minimization query for the
same zone is already pending, it might receive unexpected result codes.
Normally DNS_R_CNAME would follow to query_cname after processing sent
events, but dns_view_findzonecut does not fill CNAME target into
event->foundevent. Usual lookup via query_lookup would always have that
filled.
Ideally we would restart the query with unmodified search name, if
unexpected change from recursing to local zone cut were detected. Until
dns_view_findzonecut is modified to export zone/cache source of the cut,
at least fail queries which went into unexpected state.
The purge_stale_names()/purge_stale_entries() is opportunistic even when
we are under memory pressure (overmem). Split the opportunistic LRU
cleaning and overmem cleaning. This makes the stale purging much
simpler as we don't have to try that hard and makes the overmem cleaning
always cleanup double the amount of the newly allocated ADB name/entry.
There are three adbname flags that are used to identify different
types of adbname lookups when hashing rather than using multiple
hash tables. Separate these to their own structure element as these
need to be able to be read without locking the adbname structure.
