The 'end_serial' and some other members of the 'dns_xfrin_t'
structure can be accessed by the statistics channel, causing
a data race with the zone transfer process.
Use the existing 'statslock' mutex for protecting those members.
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.
The XFRST_INITIALSOA state in the xfrin module is named like that,
because the first RR in a zone transfer must be SOA. However, the
name of the state is a bit confusing (especially when exposed to
the users with statistics channel), because it can be mistaken with
the refresh SOA request step, which takes place before the zone
transfer starts.
Rename the state to XFRST_ZONEXFRREQUEST (i.e. Zone Transfer Request).
During that step the state machine performs several operations -
establishing a connection, sending a request, and receiving/parsing
the first RR in the answer.
Add a new field in the incoming zone transfers section of the
statistics channel to show the transport used for the SOA request.
When the transfer is started beginning from the XFRST_SOAQUERY state,
it means that the SOA query will be performed by xfrin itself, using
the same transport. Otherwise, it means that the SOA query was already
performed by other means (e.g. by zone.c:soa_query()), and, in that
case, we use the SOA query transport type information passed by the
'soa_transport_type' argument, when the xfrin object was created.
dns_xfrin_t state may be accessed from different threads when
when reporting transfer state. Ensure access is thread safe by
using atomics and locks where appropriate.
This raises the log level of messages treated as FORMERR to NOTICE
when transfering in a zone. This also adds a missing log message
for TYPE0 and meta types received during a zone transfer.
This allow for the EDNS options EXPIRE and NSID to be sent when
when making requests. The existing controls controlling whether
EDNS is used and whether EXPIRE or NSID are sent are honoured.
Adjust the expected byte counts in the xfer system test to reflect
the EDNS overhead. Adjust the dig call to match named's behavior
(don't set +expire as we are talking to a secondary).
We already print the formatted zone name via the xfrin_log() function,
generate the text once and store it in xfr->info static buffer. Then we
can reuse the string to pass it to the LIBDNS_XFRIN probes.
Add tracing probes to incoming transfers, so we can accurately measure
the individual events when sending, receiving and parsing the incoming
transfers.
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.
When a primary server is not responding, mark it as temporarialy
unreachable. This will prevent too many zones queuing up on a
unreachable server and allow the refresh process to move onto
the next primary sooner once it has been so marked.
store a pointer to the running loop when creating a dispatch entry
with dns_dispatch_add(), and use isc_loop_now() to get the timestamp for
the current event loop tick when we initialize the dispentry start time
and check for timeouts.
After the dns_xfrin was changed to use network manager, the maximum
global (max-transfer-time-in) and idle (max-transfer-idle-in) times for
incoming transfers were turned inoperational because of missing
implementation.
Restore this functionality by implementing the timers for the incoming
transfers.
As we are now using dispatch instead of netmgr for XFR TCP connection,
the xfrin_recv_done() will be called when cancelling the dispatch with
ISC_R_CANCELED. This could lead to double detach from the dns_xfrin_t,
one in the xfrin_recv_done() and one in the dns_xfrin_shutdown().
Remove the extra detach from the dns_xfrin_shutdown() and rely on the
dispatch read callback to be always called.
The xfrin_connect_done() had several problems:
- it would not add the server to unreachable table in case of the
failure coming from the dispatch [GL #3989]
- if dns_dispatch_checkperm() disallowed the connection, the xfr would
be left undetached
- if xfrin_send_request() failed to send the request, the xfr would be
left undetached
All of these have been fixed in this commit.
The isc_time_now() and isc_time_now_hires() were used inconsistently
through the code - either with status check, or without status check,
or via TIME_NOW() macro with RUNTIME_CHECK() on failure.
Refactor the isc_time_now() and isc_time_now_hires() to always fail when
getting current time has failed, and return the isc_time_t value as
return value instead of passing the pointer to result in the argument.
the dns_xfrin module was still using the network manager directly to
manage TCP connections and send and receive messages. this commit
changes it to use the dispatch manager instead.
use ISC_REFCOUNT_IMPL for dns_xfrin_ctx_t (which has been renamed
to dns_xfrin_t to keep the function names dns_xfrin_attach() and
dns_xfrin_detach() unchanged).
the 'dispatchmgr' member of the resolver object is used by both
the dns_resolver and dns_request modules, and may in the future
be used by others such as dns_xfrin. it doesn't make sense for it
to live in the resolver object; this commit moves it into dns_view.
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.
Return 'isc_result_t' type value instead of 'bool' to indicate
the actual failure. Rename the function to something not suggesting
a boolean type result. Make changes in the places where the API
function is being used to check for the result code instead of
a boolean value.
During XoT it is important to check for "dot" ALPN tag to be
negotiated (according to the RFC 9103). We were doing that, however, the
situation was not handled properly, leading to non-cancelled zone
transfers that would crash (abort()) BIND on shutdown.
In this particular case 'result' might equal 'ISC_R_SUCCESS'. When
this is the case, the part of the code supposed to handle failures
will not cancel the zone transfer.
This situation cannot happen when BIND is a secondary of other BIND
instance. Only primaries following the RFC not closely enough could
trigger such a behaviour.
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.
All we need for compression is a very small hash set of compression
offsets, because most of the information we need (the previously added
names) can be found in the message using the compression offsets.
This change combines dns_compress_find() and dns_compress_add() into
one function dns_compress_name() that both finds any existing suffix,
and adds any new prefix to the table. The old split led to performance
problems caused by duplicate names in the compression context.
Compression contexts are now either small or large, which the caller
chooses depending on the expected size of the message. There is no
dynamic resizing.
There is a behaviour change: compression now acts on all the labels in
each name, instead of just the last few.
A small benchmark suggests this is about 2x faster.
sizeof(dns_name_t) did not change but the boolean attributes are now
separated as one-bit structure members. This allows debuggers to
pretty-print dns_name_t attributes without any special hacks, plus we
got rid of manual bit manipulation code.
In order to make xfrin.c:get_create_tlsctx() reusable, move the function
into transport.c, and make changes into its prototype to not use the
'dns_xfrin_ctx_t' type, thus making it more universal.
This change prepares ground for adding transport support into the
dispatch manager.
Also, move the typedefs for 'dns_transport_t' and 'dns_transport_list_t'
from transport.h into types.h.
Clean up dns_rdatalist_tordataset() and dns_rdatalist_fromrdataset()
functions by making them return void, because they cannot fail.
Clean up other functions that subsequently cannot fail.
There was a proposal in the late 1990s that it might, but it turned
out to be unworkable. See RFC 6891, Extension Mechanisms for
DNS (EDNS(0)), section 5, Extended Label Types.
The remnants of the code that supported this in BIND are redundant.
This commit separates TLS context creation code from xfrin_start() as
it has become too large and hard to follow into a new
function (similarly how it is done in dighost.c)
The dead code has been removed from the cleanup section of the TLS
creation code:
* there is no way 'tlsctx' can equal 'found';
* there is no way 'sess_cache' can be non-NULL in the cleanup section.
Also, it fixes a bug in the older version of the code, where TLS
client session context fetched from the cache would not get passed to
isc_nm_tlsdnsconnect().
This commit extends TLS context cache with TLS client session cache so
that an associated session cache can be stored alongside the TLS
context within the context cache.
The dns_message_gettempname(), dns_message_gettemprdata(),
dns_message_gettemprdataset(), and dns_message_gettemprdatalist() always
succeeds because the memory allocation cannot fail now. Change the API
to return void and cleanup all the use of aforementioned functions.
This commit adds support for Strict/Mutual TLS into BIND. It does so
by implementing the backing code for 'hostname' and 'ca-file' options
of the 'tls' statement. The commit also updates the documentation
accordingly.
This commit adds support for keeping CA certificates stores associated
with TLS contexts. The intention is to keep one reusable store per a
set of related TLS contexts.
Previously, it was possible to assign a bit of memory space in the
nmhandle to store the client data. This was complicated and prevents
further refactoring of isc_nmhandle_t caching (future work).
Instead of caching the data in the nmhandle, allocate the hot-path
ns_client_t objects from per-thread clientmgr memory context and just
assign it to the isc_nmhandle_t via isc_nmhandle_set().
Previously, the unreachable code paths would have to be tagged with:
INSIST(0);
ISC_UNREACHABLE();
There was also older parts of the code that used comment annotation:
/* NOTREACHED */
Unify the handling of unreachable code paths to just use:
UNREACHABLE();
The UNREACHABLE() macro now asserts when reached and also uses
__builtin_unreachable(); when such builtin is available in the compiler.
