Meson is a modern build system that has seen a rise in adoption and some
version of it is available in almost every platform supported.
Compared to automake, meson has the following advantages:
* Meson provides a significant boost to the build and configuration time
by better exploiting parallelism.
* Meson is subjectively considered to be better in readability.
These merits alone justify experimenting with meson as a way of
improving development time and ergonomics. However, there are some
compromises to ensure the transition goes relatively smooth:
* The system tests currently rely on various files within the source
directory. Changing this requirement is a non-trivial task that can't
be currently justified. Currently the last compiled build directory
writes into the source tree which is in turn used by pytest.
* The minimum version supported has been fixed at 0.61. Increasing this
value will require choosing a baseline of distributions that can
package with meson. On the contrary, there will likely be an attempt
to decrease this value to ensure almost universal support for building
BIND 9 with meson.
A "template" statement can contain the same configuration clauses
as a "zone" statement. A "zone" statement can now reference a
template, and all the clauses in that template will be used as
default values for the zone. For example:
template primary {
type primary;
file "$name.db";
initial-file "primary.db";
};
zone example.com {
template primary;
file "different-name.db"; // overrides the template
};
Special tokens can now be specified in a zone "file" option
in order to generate the filename parametrically. The first
instead of "$name" in the "file" option is replaced with the
zone origin, the first instance of "$type" is replaced with the
zone type (i.e., primary, secondary, etc), and the first instance
of "$view" is replaced with the view name..
This simplifies the creation of zones using initial-file templates.
For example:
$ rndc addzone <zonename> \
{ type primary; file "$name.db"; initial-file "template.db"
When loading a primary zone for the first time, if the zonefile
does not exist but an "initial-file" option has been set, then a
new file will be copied into place from the path specified by
"initial-file".
This can be used to simplify the process of adding new zones. For
instance, a template zonefile could be used by running:
$ rndc addzone example.com \
'{ type primary; file "example.db"; initial-file "template.db"; };'
Instead of giving the memory context names with an explicit call to
isc_mem_setname(), add the name to isc_mem_create() call to have all the
memory contexts an unconditional name.
The `max-rsa-exponent-size` could limit the exponents of the RSA
public keys during the DNSSEC verification. Instead of providing
a cryptic (not cryptographic) knob, hardcode the max exponent to
be 4096 (the theoretical maximum for DNSSEC).
This new option sets the delay, in seconds, to wait before sending
a set of NOTIFY messages for a zone. Whenever a NOTIFY message is
ready to be sent, sending will be deferred for this duration.
The check fails with the following error for some time:
broken https://www.gnu.org/software/libidn/#libidn2 - HTTPSConnectionPool(host='www.gnu.org', port=443): Max retries exceeded with url: /software/libidn/ (Caused by NewConnectionError('<urllib3.connection.HTTPSConnection object at 0x7f5bd4c14590>: Failed to establish a new connection: [Errno 111] Connection refused'))
The new 'tcp-primaries-timeout' configuration option works the same way
as the existing 'tcp-initial-timeout' option, but applies only to the
TCP connections made to the primary servers, so that the timeout value
can be set separately for them. The default is 15 seconds.
Also, while accommodating zone.c's code to support the new option, make
a light refactoring with the way UDP timeouts are calculated by using
definitions instead of hardcoded values.
With dnssec-policy you can pregenerate keys and if they are eligible,
rather than creating a new key, a key is selected from the pregenerated
keys. A key is eligible if it is unused, i.e it has no key timing
metadata set.
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.
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 offsets were meant to speed-up the repeated dns_name operations, but
it was experimentally proven that there's actually no real-world
benefit. Remove the offsets and labels fields from the dns_name and the
static offsets fields to save 128 bytes from the fixedname in favor of
calculating labels and offsets only when needed.
Instead of relying on unreliable order of execution of the library
constructors and destructors, move them to individual binaries. The
advantage is that the execution time and order will remain constant and
will not depend on the dynamic load dependency solver.
This requires more work, but that was mitigated by a simple requirement,
any executable using libisc and libdns, must include <isc/lib.h> and
<dns/lib.h> respectively (in this particular order). In turn, these two
headers must not be included from within any library as they contain
inlined functions marked with constructor/destructor attributes.
Previously a hard-coded limitation of maximum two key or message
verification checks were introduced when checking the message's
SIG(0) signature. It was done in order to protect against possible
DoS attacks. The logic behind choosing the number two was that more
than one key should only be required only during key rotations, and
in that case two keys are enough. But later it became apparent that
there are other use cases too where even more keys are required, see
issue number #5050 in GitLab.
This change introduces two new configuration options for the views,
sig0key-checks-limit and sig0message-checks-limit, which define how
many keys are allowed to be checked to find a matching key, and how
many message verifications are allowed to take place once a matching
key has been found. The latter protects against expensive cryptographic
operations when there are keys with colliding tags and algorithm
numbers, with default being 2, and the former protects against a bit
less expensive key parsing operations and defaults to 16.
Expose the average transfer rate (in bytes-per-second) during the
last full 'min-transfer-rate-in <bytes> <minutes>' minutes interval.
If no such interval has passed yet, then the overall average rate is
reported instead.
This new option sets a minimum amount of transfer rate for
an incoming zone transfer that will abort a transfer, which
for some network related reasons run very slowly.
