The high-water allows administrators to better tune the recursive
clients limit without having to to poll the statistics channel in high
rates to get this number.
Returning the value allows for better high-water tracking without
running into edge cases like the following:
0. The counter is at value X
1. Increment the value (X+1)
2. The value is decreased multiple times in another threads (X+1-Y)
3. Get the value (X+1-Y)
4. Update-if-greater misses the X+1 value which should have been the
high-water
An RPZ response's SOA record TTL is set to 1 instead of the SOA TTL,
a boolean value is passed on to query_addsoa, which is supposed to be
a TTL value. I don't see what value is appropriate to be used for
overriding, so we will pass UINT32_MAX.
Because some tests don't have a legtimate handle, provide a temporary
return early that should be fixed and removed before squashing. This
short circuiting is still correct until DoQ/DoH3 support is introduced.
GCC might fail to compile because it expects a return after UNREACHABLE.
It should ideally just work anyway since UNREACHABLE is either a
noreturn or UB (__builtin_unreachable / C23 unreachable).
Either way, it should be optimized almost always so the fallback is
free or basically free anyway when it isn't optimized out.
This commit ensures that worker threads are not sleeping (by using
select()) when '-T transferslowly/transferstuck' test options are
used. This commit converts synchronous implementation of the code into
an asynchronous one based on timers.
Use the (1 << N) form for defining the flags, in order to avoid
errors like the one fixed in the previous commit.
Also convert the definitions to an enum, as done in some of our
recent refactoring work.
The DNS_GETDB_STALEFIRST flag is defined as 0x0C, which is the
combination of the DNS_GETDB_PARTIAL (0x04) and the
DNS_GETDB_IGNOREACL (0x08) flags (0x04 | 0x08 == 0x0C) , which is
an obvious error.
All the flags should be power of two, so they don't interfere with
each other. Fix the DNS_GETDB_STALEFIRST flag by setting it to 0x10.
The older version of the code was reporting that listeners are going
to be of the same type after reconfiguration when switching from DoT
to HTTPS listener, making BIND abort its executions.
That was happening due to the flaw in logic due to which the code
could consider a current listener and a configuration for the new one
to be of the same type (DoT) even when the new listener entry is
explicitly marked as HTTP.
The checks for PROXY in between the configuration were masking that
behaviour, but when porting it to 9.18 (when there is no PROXY
support), the behaviour was exposed.
Now the code mirrors the logic in 'interface_setup()' closely (as it
was meant to).
When processing UPDATE request DNSKEY, CDNSKEY and CDS record that
are managed by named are filtered out. The log message has been
updated to report the actual type rather that just DNSKEY.
This commit ensures that listeners are recreated on reconfiguration in
the case when their type changes (or when PROXY protocol type changes,
too).
Previously, if a "listen-on" statement was modified to represent a
different transport, BIND would not pick-up the change on
reconfiguration if listener type changes (e.g. DoH -> DoT) for a given
interface address and port combination. This commit fixes that by
recreating the listener.
Initially, that worked for most of the new transports as we would
recreate listeners on each reconfiguration for DoH and DoT. But at
some point we changed that in such a way that listeners were not
recreated to avoid rebinding a port as on some platforms only root can
do that for port numbers <1000, making some ports binding possible
only on start-up. We chose to asynchronously update listener socket
settings (like TLS contexts, HTTP settings) instead.
Now, we both avoid recreating the sockets if unnecessary and recreate
listeners when listener type changes.
If we are in the process of looking for the A records as part of
dns64 processing and the server-stale timeout triggers, redo the
dns64 changes that had been made to the orignal qctx.
The wrong result value was being saved for resumption with
nxdomain-redirect when performing the fetch. This lead to an assert
when checking that RFC 1918 reverse queries where not leaking to
the global internet.
The main intention of PROXY protocol is to pass endpoints information
to a back-end server (in our case - BIND). That means that it is a
valid way to spoof endpoints information, as the addresses and ports
extracted from PROXYv2 headers, from the point of view of BIND, are
used instead of the real connection addresses.
Of course, an ability to easily spoof endpoints information can be
considered a security issue when used uncontrollably. To resolve that,
we introduce 'allow-proxy' and 'allow-proxy-on' ACL options. These are
the only ACL options in BIND that work with real PROXY connections
addresses, allowing a DNS server operator to specify from what clients
and on which interfaces he or she is willing to accept PROXY
headers. By default, for security reasons we do not allow to accept
them.
This commit extends "listen-on" statement with "proxy" options that
allows one to enable PROXYv2 support on a dedicated listener. It can
have the following values:
- "plain" to send PROXYv2 headers without encryption, even in the case
of encrypted transports.
- "encrypted" to send PROXYv2 headers encrypted right after the TLS
handshake.
The AES algorithm for DNS cookies was being kept for legacy reasons, and
it can be safely removed in the next major release. Remove both the AES
usage for DNS cookies and the AES implementation itself.
When serve-stale is enabled and recursive resolution fails, the fallback
to lookup stale data always happens in the cache database. Any
authoritative data is ignored, and only information learned through
recursive resolution is examined.
If there is data in the cache that could lead to an answer, and this can
be just the root delegation, the resolver will iterate further, getting
closer to the answer that can be found by recursing down the root, and
eventually puts the final response in the cache.
Change the fallback to serve-stale to use 'query_getdb()', that finds
out the best matching database for the given query.
The dns_aclenv_t contains two dns_acl_t - localhost and localnets that
can be swapped with a different ACLs as we configure BIND 9. Instead of
protecting those two pointers with heavyweight read-write lock, use RCU
mechanism to dereference and swap the pointers.
All these pointers are guaranteed to be non-NULL.
Additionally, update a comment to remove obviously outdated
information about the function's requirements.
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.
Instead of high number of dispatches (4 * named_g_udpdisp)[1], make the
dispatches bound to threads and make dns_dispatchset_t create a dispatch
for each thread (event loop).
This required couple of other changes:
1. The dns_dispatch_createudp() must be called on loop, so the isc_tid()
is already initialized - changes to nsupdate and mdig were required.
2. The dns_requestmgr had only a single dispatch per v4 and v6. Instead
of using single dispatch, use dns_dispatchset_t for each protocol -
this is same as dns_resolver.
rr_exists errored if the name did not exist in the zone. This was
not an issue prior to the addition of krb5-subdomain-self-rhs and
ms-subdomain-self-rhs as the only name used was the zone name which
always existed.
when synthesizing a new CNAME, we now check whether the target
matches the query already being processed. if so, we do not
restart the query; this prevents a waste of resources.
Add a trace point that would report when a query gets dropped or slipped
by rate limits. It reports the client IP, the zone, and the RRL result
code.
Co-authored-by: Paul Frieden <pfrieden@yahooinc.com>
This adds support for User Statically Defined Tracing (USDT). On
Linux, this uses the header from SystemTap and dtrace utility, but the
support is universal as long as dtrace is available.
Also add the required infrastructure to add probes to libisc, libdns and
libns libraries, where most of the probes will be.
The dns_badcache unit had (yet another) own locked hashtable
implementation. Replace the hashtable used by dns_badcache with
lock-free cds_lfht implementation from liburcu.
The isc_stats_create() can no longer return anything else than
ISC_R_SUCCESS. Refactor isc_stats_create() and its variants in libdns,
libns and named to just return void.
We removed DNSSEC management via dynamic update (see issue #3686),
this means we also should no longer add signing records (of private
type) for DNSKEY records added via dynamic update.
