The slabheader.c, qpzone.c and qpcache.c had couple of shared macros
that were copied and paste between the units. Move these common
attributes access macros into private header, so these can be shared
among the three compilation units.
In the dns_qpcache unit, we use EXISTS() macro, but in the dns_qpzone
there's a NONEXISTENT() macro for the same slabheader attribute. Unify
the macro to be also EXISTS() in dns_qpzone.
Previously, when a negative header was stored in the cache, it would be
stored in the dns_typepair_t as .type = 0, .covers = <negative type>.
When searching the cache internally, we would have to look for both
positive and negative typepair and the slabheader .down list could be a
mix of positive and negative types.
Remove the extra representation of the negative type and simply use the
negative attribute on the slabheader. Other units (namely dns_ncache)
can still insert the (0, type) negative rdatasets into the cache, but
internally, those will be converted into (type, 0) slabheaders, and vice
versa - when binding the rdatasets, the negative (type, 0) slabheader
will be converted to (0, type) rdataset. Simple DNS_TYPEPAIR() helper
macro was added to simplify converting single rdatatype to typepair
value.
As a side-effect, the search logic in all places can exit early if
there's a negative header for the type we are looking for, f.e. when
searching for the zone cut, we don't have to walk through all the
slabheaders, if there's a stored negative slabheader.
Use dns_rdatatype_none instead of plain '0' for dns_rdatatype_t and
dns_typepair_t manipulation. While plain '0' is technically ok, it
doesn't carry the required semantic meaning, and using the named
dns_rdatatype_none constant makes the code more readable.
When in developer's mode, make the DNS_TYPEPAIR_* macros be more
strict on the contents of the 'base' and 'covers', so we can catch
invalid use of the API.
The RR type 0 is a reserved type for SIG[1] resource record. It should
not be ever inserted into the database nor queried. Add a special
handling to bail out quickly with DNS_R_DISALLOWED when inserting and
ISC_R_NOTFOUND when looking up TYPE0. This is also prerequisite for
stricter checks in the follow-up commit.
1. https://www.rfc-editor.org/rfc/rfc2535#section-4.1.8.1
The dns_typepair_t and dns_rdatatype_t variables were both named 'type'
in multiple places. Rename all dns_typepair_t variables to include word
'pair' in the variable name to make sure that the distinction between
the two types is more clear.
Instead of catching the DNS_R_UNCHANGED from dns_db_addrdataset() (via
cache_rrset() and dns_ncache_add()) individually, mask it properly as
soon as possible, by moving the sigrdataset caching logic inside
cache_rrset() and returning ISC_R_SUCCESS from cache_rrset() and
dns_ncache_add() when the database was unchanged.
The logic to delete records from the cache was relying on the contents
of the validation answer. Change the logic to always delete the
contents of the cache on the broken chain result.
during a recent refactoring of validated(), a line was
removed, causing 'result' to be left unchanged. this
wasted time continuing to try to validate when a
non-recoverable error had occured, and caused the wrong
reason to be logged in add_bad().
Initialization of the common members of rdata type structures varies
across branches. Standardize it by using the DNS_RDATACOMMON_INIT
macro for all types, so that new types are more likely to use it,
and hence backport more cleanly.
All databases in the codebase follow the same structure: a database is
an associative container from DNS names to nodes, and each node is an
associative container from RR types to RR data.
Each database implementation (qpzone, qpcache, sdlz, builtin, dyndb) has
its own corresponding node type (qpznode, qpcnode, etc). However, some
code needs to work with nodes generically regardless of their specific
type - for example, to acquire locks, manage references, or
register/unregister slabs from the heap.
Currently, these generic node operations are implemented as methods in
the database vtable, which creates problematic coupling between database
and node lifetimes. If a node outlives its parent database, the node
destructor will destroy all RR data, and each RR data destructor will
try to unregister from heaps by calling a virtual function from the
database vtable. Since the database was already freed, this causes a
crash.
This commit breaks the coupling by standardizing the layout of all
database nodes, adding a dedicated vtable for node operations, and
moving node-specific methods from the database vtable to the node
vtable.
Right now dns_sdlzlookup has a slight difference from other dbnode
implementations in that it stores a pointer to a dns name instead of
the dns name itself.
This commit harmonizes dns_sdlzlookup with other dbnode
implementations, facilitating further refactoring.
- there was special-case code in validated() to handle the results
of a validator started by a CD=1 query. since that never happens,
the code has been removed.
- the section of code that handles opportunistic caching of
validated SOA, NS and NSEC data has been split out to a separate
function.
- the number of goto statements has been reduced considerably.
- fctx_setresult() sets the event result in a fetch response
according to the rdataset being returned - DNS_R_NCACHENXDOMAIN or
DNS_R_NXRRSET for negative responses, ISC_R_SUCCESS, DNS_R_CNAME,
or DNS_R_DNAME for positive ones.
- cache_rrset() looks up a node and adds an rdataset.
- delete_rrset() looks up a node and removes rdatasets of a specified
type and, optionally, the associated signatures.
- gettrust() returns the trust level of an rdataset, or dns_trust_none
if the rdataset is NULL or not associated.
- getrrsig() scans the rdatasets associated with a name for the
RRSIG covering a given type.
rctx_cacherdataset() has been split into two functions:
- rctx_cache_secure() starts validation for rdatasets
that need it; they are then cached by the validator
completion callback validated()
- rctx_cache_insecure() caches rdatasets immediately; it
is called when validation is disabled or the data
to be cached is glue.
- renamed cache_message() to rctx_cachemessage()
- renamed cache_name() to rctx_cachename()
- merged ncache_message() into rctx_ncache()
- split out a new function, rctx_cacherdataset(), which is
called by rctx_cachename() in a loop to process each of
the rdatasets associated with the name.
every call to findnoqname() was followed by a call to
dns_rdataset_addnoqname(). we can move that call into
findnoqname() itself, and simplify the calling functions
a bit.
previously, rctx_answer_any() set the ANSWER flag for all
rdatasets in the answer section; it now sets ANSWERSIG for
RRSIG/SIG rdatasets and ANSWER for everything else. this
error didn't cause any harm in the current code, but it
could have led to unexpected behavior in the future.
there are now separate functions to check the cacheability of
an rdataset or to normalize TTLs, and the code to determine
whether validation is necessary has been simplified.
- dns_rdataset_issigtype() returns true if the rdataset is
of type RRSIG and covers a specified type
- dns_rdataset_matchestype() returns true if the rdataset
is of the specified type *or* the RRSIG covering it.
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.
