> Put a space before opening parentheses only after control statement
> keywords (for/if/while...) except this option doesn’t apply to ForEach
> and If macros. This is useful in projects where ForEach/If macros are
> treated as function calls instead of control statements.
When first dns_db_addrdataset() succeeds in cache_rrset(), but the
second one fails with error, the added rdataset was kept associated.
This caused assertion failure down the pipe in fctx_sendevents().
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().
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.
- 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.
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.
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.
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.
Change the internal type used for isc_tid unit to isc_tid_t to hide the
specific integer type being used for the 'tid'. Internally, the signed
integer type is being used. This allows us to have negatively indexed
arrays that works both for threads with assigned tid and the threads
with unassigned tid. This should be used only in specific situations.
dns_resolver_algorithm_supported() has been extended so in addition to
an algorithm number, it can also take a pointer to an RRSIG signature
field in which key information is encoded.
The algorithm values PRIVATEDNS and PRIVATEOID are placeholders,
signifying that the actual algorithm identifier is encoded into the
key data. Keys using this mechanism are now supported.
- The algorithm values PRIVATEDNS and PRIVATEOID cannot be used to
build a key file name; dst_key_buildfilename() will assert if
they are used.
- The DST key values for private algorithms are higher than 255.
Since DST_ALG_MAXALG now exceeds 256, algorithm arrays that were
previously hardcoded to size 256 have been resized.
- New mnemonic/text conversion functions have been added.
dst_algorithm_{fromtext,totext,format} can handle algorithm
identifiers encoded in PRIVATEDNS and PRIVATEOID keys, as well
as the traditional algorithm identifiers. (Note: The existing
dns_secalg_{fromtext,totext,format} functions are similar, but
do *not* support PRIVATEDNS and PRIVATEOID. In most cases, the
new functions have taken the place of the old ones, but in a few
cases the old version is still appropriate.)
- dns_private{oid,dns}_{fromtext,totext,format} converts between
DST algorithm values and the mnemonic strings for algorithms
implemented using PRIVATEDNS or PRIVATEOID. (E.g., "RSASHA256OID").
- dst_algorithm_tosecalg() returns the DNSSEC algorithm identifier
that applies for a given DST algorithm. For PRIVATEDNS- or
PRIVATEOID- based algorithms, the result will be PRIVATEDNS or
PRIVATEOID, respectively.
- dst_algorithm_fromprivatedns() and dst_algorithm_fromprivateoid()
return the DST algorithm identifier for an encoded algorithm in
wire format, represented as in DNS name or an object identifier,
respectively.
- dst_algorithm_fromdata() is a front-end for the above; it extracts
the private algorithm identifier encoded at the begining of a
block of key or signature data, and returns the matching DST
algorithm number.
- dst_key_fromdns() and dst_key_frombuffer() now work with keys
that have PRIVATEDNS and PRIVATEOID algorithm identifiers at the
beginning.
replace the pattern `for (result = dns_rdataset_first(x); result ==
ISC_R_SUCCES; result = dns_rdataset_next(x)` with a new
`DNS_RDATASET_FOREACH` macro throughout BIND.
previously, ISC_LIST_FOREACH and ISC_LIST_FOREACH_SAFE were
two separate macros, with the _SAFE version allowing entries
to be unlinked during the loop. ISC_LIST_FOREACH is now also
safe, and the separate _SAFE macro has been removed.
similarly, the ISC_LIST_FOREACH_REV macro is now safe, and
ISC_LIST_FOREACH_REV_SAFE has also been removed.
the pattern `for (x = ISC_LIST_HEAD(...); x != NULL; ISC_LIST_NEXT(...)`
has been changed to `ISC_LIST_FOREACH` throughout BIND, except in a few
cases where the change would be excessively complex.
in most cases this was a straightforward change. in some places,
however, the list element variable was referenced after the loop
ended, and the code was refactored to avoid this necessity.
also, because `ISC_LIST_FOREACH` uses typeof(list.head) to declare
the list elements, compilation failures can occur if the list object
has a `const` qualifier. some `const` qualifiers have been removed
from function parameters to avoid this problem, and where that was not
possible, `UNCONST` was used.
ISC_LIST_FOREACH and related macros now use 'typeof(list.head)' to
declare the list elements automatically; the caller no longer needs
to do so.
ISC_LIST_FOREACH_SAFE also now implicitly declares its own 'next'
pointer, so it only needs three parameters instead of four.
In the code base it is very common to iterate over all names in a message
section and all rdatasets for each name, but various idioms are used for
iteration.
This commit standardizes them as much as possible to a single idiom,
using the macro MSG_SECTION_FOREACH, similar to the existing
ISC_LIST_FOREACH.
when sending a query to a forwarder for a name within a secure domain,
the first query is now sent with CD=0. when the forwarder itself
is validating, this will give it a chance to detect bogus data and
replace it with valid data before answering. this reduces our chances
of being stuck with data that can't be validated.
if the forwarder returns SERVFAIL to the initial query, the query
will be repeated with CD=1, to allow for the possibility that the
forwarder's validator is faulty or that the bogus answer is covered
by an NTA.
note: previously, CD=1 was only sent when the query name was in a
secure domain. today, validating servers have a trust anchor at the
root by default, so virtually all queries are in a secure domain.
therefore, the code has been simplified. as long as validation is
enabled, any forward query that receives a SERVFAIL response will be
retried with CD=1.
This can be set at the option, view and server levels and causes
named to add an EDNS ZONEVERSION option to requests. Replies are
logged to the 'zoneversion' category.
The fetch context that held these values could be freed while there
were still active pointers to the memory. Using a reference counted
pointer avoids this.
When a response times out the fctx_cancelquery() function
incorrectly calculates it in the 'dns_resstatscounter_queryrtt5'
counter (i.e. >=1600 ms). To avoid this, the rctx_timedout()
function should make sure that 'rctx->finish' is NULL. And in order
to adjust the RTT values for the timed out server, 'rctx->no_response'
should be true. Update the rctx_timedout() function to make those
changes.
The resquery_response() function increases the response counter without
checking if the response was successful. Increase the counter only when
the result indicates success.
There were kludges to help process responses from authoritative servers
giving RRs in wrong sections (mentioning BIND 8). These should just go
away and such responses should not be processed.
When performing QNAME minimization, named now sends an NS
query for the original QNAME, to prevent the parent zone from
receiving the QTYPE.
For example, when looking up example.com/A, we now send NS queries
for both com and example.com before sending the A query to the
servers for example.com. Previously, an A query for example.com
would have been sent to the servers for com.
Several system tests needed to be adjusted for the new query pattern:
- Some queries in the serve-stale test were sent to the wrong server.
- The synthfromdnssec test could fail due to timing issues; this
has been addressed by adding a 1-second delay.
- The cookie test could fail due to the a change in the count of
TSIG records received in the "check that missing COOKIE with a
valid TSIG signed response does not trigger TCP fallback" test case.
- The GL #4652 regression test case in the chain system test depends
on a particular query order, which no longer occurs when QNAME
minimization is active. We now disable qname-minimization
for that test.
If a timeout occurs when sending a QMIN query, QNAME
minimization should be disabled. This now causes a hard
failure in strict mode, or a fallback to non-minimized queries
in relaxed mode.
The calling fetch has already called fcount_incr() for this zone;
calling it again for a QMIN query results in double counting.
When resuming after a QMIN query is answered, however, we do now
ensure before continuing that the fetches-per-zone limit has not
been exceeded.
when the caching of a negative record failed because of the
presence of a positive one, ncache_adderesult() could override
this to ISC_R_SUCCESS. this could cause CNAME and DNAME responses
to be handled incorrectly. ncache_adderesult() now sets the result
code correctly in such cases.
the target name parameter to dns_adb_createfind() was always passed as
NULL, so we can safely remove it.
relatedly, the 'target' field in the dns_adbname structure was never
referenced after being set. the 'expire_target' field was used, but
only as a way to check whether an ADB name represents a CNAME or DNAME,
and that information can be stored as a single flag.
Named was stopping nameserver address resolution attempts too soon
when dual stack servers are configured. Dual stack servers are
used when there are *not* addresses for the server in a particular
address family so find->status == DNS_ADB_NOMOREADDRESSES is not a
sufficient stopping condition when dual stack servers are available.
Call fctx_try to see if the alternate servers can be used.
