Previously, there was no limit to the number of concurrently served
queries over one pipelined TCP connection; an unlimited number of
queries sent over a single TCP connection could have potentially
exhausted the server's resources.
This variable will report the maximum number of simultaneous tcp clients
that BIND has served while running.
It can be verified by running rndc status, then inspect "tcp high-water:
count", or by generating statistics file, rndc stats, then inspect the
line with "TCP connection high-water" text.
The tcp-highwater variable is atomically updated based on an existing
tcp-quota system handled in ns/client.c.
(cherry picked from commit 66fe8627de)
The named_g_defaultdnstap was never used as the dnstap requires
explicit configuration of the output file.
Related scan-build report:
./server.c:3476:14: warning: Value stored to 'dpath' during its initialization is never read
const char *dpath = named_g_defaultdnstap;
^~~~~ ~~~~~~~~~~~~~~~~~~~~~
1 warning generated.
(cherry picked from commit 6decd14592)
Until now, the build process for BIND on Windows involved upgrading the
solution file to the version of Visual Studio used on the build host.
Unfortunately, the executable used for that (devenv.exe) is not part of
Visual Studio Build Tools and thus there is no clean way to make that
executable part of a Windows Server container.
Luckily, the solution upgrade process boils down to just adding XML tags
to Visual Studio project files and modifying certain XML attributes - in
files which we pregenerate anyway using win32utils/Configure. Thus,
extend win32utils/Configure with three new command line parameters that
enable it to mimic what "devenv.exe bind9.sln /upgrade" does. This
makes the devenv.exe build step redundant and thus facilitates building
BIND in Windows Server containers.
(cherry picked from commit 0476e8f1ac)
Make stderr fully buffered on Windows to improve named performance when
it is logging to stderr, which happens e.g. in system tests. Note that:
- line buffering (_IOLBF) is unavailable on Windows,
- fflush() is called anyway after each log message gets written to the
default stderr logging channels created by libisc.
(cherry picked from commit c72da3497d)
BIND system tests are run in a Cygwin environment. Apparently Cygwin
shell sets the SEM_NOGPFAULTERRORBOX bit in its process error mode which
is then inherited by all spawned child processes. This bit prevents the
Windows Error Reporting dialog from being displayed, which I assume is
part of an effort to contain memory handling errors triggered by Cygwin
binaries in the Cygwin environment. Unfortunately, this also prevents
automatic crash dump creation by Windows Error Reporting and Cygwin
itself does not handle memory errors in native Windows processes spawned
from a Cygwin shell.
Fix by clearing the SEM_NOGPFAULTERRORBOX bit inside named if it is
started in a Cygwin environment, thus overriding the Cygwin-set process
error mode in order to enable Windows Error Reporting to handle all
named crashes.
(cherry picked from commit 3d4b17806f)
When libxml2 is to be used in a multi-threaded application, the
xmlInitThreads() function must be called before any other libxml2
function. This function does different things on various platforms and
thus one can get away without calling it on Unix systems, but not on
Windows, where it initializes critical section objects used for
synchronizing access to data structures shared between threads. Add the
missing xmlInitThreads() call to prevent crashes on affected systems.
Also add a matching xmlCleanupThreads() call to properly release the
resources set up by xmlInitThreads().
(cherry picked from commit a3c0b00ef6)
Addresses the database changing w/o the changes being done under task lock.
Fix: build the database before assigning it to the zone.
(cherry picked from commit 4e686f40e0)
For some libc implementations, BUFSIZ is small enough (e.g. 1024 for
musl libc) to trigger compilation warnings about insufficient size of
certain buffers. Since the relevant buffers are used for printing DNS
names, increase their size to '(n + 1) * DNS_NAME_FORMATSIZE', where 'n'
is the number of DNS names which are printed to a given buffer. This
results in somewhat arbitrary, albeit nicely-aligned and large enough
buffer sizes.
(cherry picked from commit 3384455659)
Including <sys/errno.h> instead of <errno.h> raises a compiler warning
when building against musl libc. Always include <errno.h> instead of
<sys/errno.h> to prevent that compilation warning from being triggered
and to achieve consistency in this regard across the entire source tree.
(cherry picked from commit b5cd146033)
This commit changes the BIND cookie algorithms to match
draft-sury-toorop-dnsop-server-cookies-00. Namely, it changes the Client Cookie
algorithm to use SipHash 2-4, adds the new Server Cookie algorithm using SipHash
2-4. The change doesn't make the SipHash 2-4 to be the default algorithm, this
is up to the operator.
(cherry picked from commit 196b342bc9)
- revise mapping of search terms to database types to match the
GeoIP2 schemas.
- open GeoIP2 databases when starting up; close when shutting down.
- clarify the logged error message when an unknown database type
is configured.
- add new geoip ACL subtypes to support searching for continent in
country databases.
- map geoip ACL subtypes to specific MMDB database queries.
- perform MMDB lookups based on subtype, saving state between
queries so repeated lookups for the same address aren't necessary.
(cherry picked from commit 6e0b93e5a0)
(cherry picked from commit 0283ab7512)
- "--with-geoip" is used to enable the legacy GeoIP library.
- "--with-geoip2" is used to enable the new GeoIP2 library
(libmaxminddb), and is on by default if the library is found.
- using both "--with-geoip" and "--with-geoip2" at the same time
is an error.
- an attempt is made to determine the default GeoIP2 database path at
compile time if pkg-config is able to report the module prefix. if
this fails, it will be necessary to set the path in named.conf with
geoip-directory
- Makefiles have been updated, and a stub lib/dns/geoip2.c has been
added for the eventual GeoIP2 search implementation.
(cherry picked from commit fea6b5bf10)
(cherry picked from commit 6a7e805796)
In ISC-Bugs 45340, I wrote:
The Statistics channel offers links to Zones and Traffic.
Both produce valid data, but display as blank pages with
a web browser.
Zones never had XSL (I provided the original
implementation, but punted on the XSL).
Traffic has XSL, but it wasn't updated to reflect the
split between IPv4 and IPv6 data.
I've picked up enough XSL to fix my original omission,
and as penance for my sloth, fixed the Traffic bug as well.
(cherry picked from commit 96f0bbd4d5)
- when processing authoritative queries for ./NS, set 'gluedb' so
that glue will be included in the response, regardless of how
'minimal-responses' has been configured.
(cherry picked from commit e7684c7b64)
We increase recursclients when we attach to recursion quota,
decrease when we detach. In some cases, when we hit soft
quota, we might attach to quota without increasing recursclients
gauge. We then decrease the gauge when we detach from quota,
and it causes the statistics to underflow.
Fix makes sure that we increase recursclients always when we
succesfully attach to recursion quota.
Backport named command line switches implemented in commit
c81c9660f5 as they are needed by the
"legacy" system checks which are currently present in master and v9_14
branches, but missing in the v9_11 branch.
in the "refactor tcpquota and pipeline refs" commit, the counting
of active interfaces was tightened in such a way that named could
fail to listen on an interface if there were more interfaces than
tcp-clients. when checking the quota to start accepting on an
interface, if the number of active clients was above zero, then
it was presumed that some other client was able to handle accepting
new connections. this, however, ignored the fact that the current client
could be included in that count, so if the quota was already exceeded
before all the interfaces were listening, some interfaces would never
listen.
we now check whether the current client has been marked active; if so,
then the number of active clients on the interface must be greater
than 1, not 0.
(cherry picked from commit 0b4e2cd4c3192ba88569dd344f542a8cc43742b5)
(cherry picked from commit d01023aaac)
- if the TCP quota has been exceeded but there are no clients listening
for new connections on the interface, we can now force attachment to the
quota using isc_quota_force(), instead of carrying on with the quota not
attached.
- the TCP client quota is now referenced via a reference-counted
'ns_tcpconn' object, one of which is created whenever a client begins
listening for new connections, and attached to by members of that
client's pipeline group. when the last reference to the tcpconn
object is detached, it is freed and the TCP quota slot is released.
- reduce code duplication by adding mark_tcp_active() function.
- convert counters to atomic.
(cherry picked from commit 7e8222378ca24f1302a0c1c638565050ab04681b)
(cherry picked from commit 4939451275722bfda490ea86ca13e84f6bc71e46)
(cherry picked from commit 13f7c918b8)
- ensure that tcpactive is cleaned up correctly when accept() fails.
- set 'client->tcpattached' when the client is attached to the tcpquota.
carry this value on to new clients sharing the same pipeline group.
don't call isc_quota_detach() on the tcpquota unless tcpattached is
set. this way clients that were allowed to accept TCP connections
despite being over quota (and therefore, were never attached to the
quota) will not inadvertently detach from it and mess up the
accounting.
- simplify the code for tcpquota disconnection by using a new function
tcpquota_disconnect().
- before deciding whether to reject a new connection due to quota
exhaustion, check to see whether there are at least two active
clients. previously, this was "at least one", but that could be
insufficient if there was one other client in READING state (waiting
for messages on an open connection) but none in READY (listening
for new connections).
- before deciding whether a TCP client object can to go inactive, we
must ensure there are enough other clients to maintain service
afterward -- both accepting new connections and reading/processing new
queries. A TCP client can't shut down unless at least one
client is accepting new connections and (in the case of pipelined
clients) at least one additional client is waiting to read.
(cherry picked from commit c7394738b2445c16f728a88394864dd61baad900)
(cherry picked from commit e965d5f11d3d0f6d59704e614fceca2093cb1856)
(cherry picked from commit 87d4311614)
Track pipeline groups using a shared reference counter
instead of a linked list.
(cherry picked from commit 513afd33eb17d5dc41a3f0d2d38204ef8c5f6f91)
(cherry picked from commit 9446629b73)
the TCP client quota could still be ineffective under some
circumstances. this change:
- improves quota accounting to ensure that TCP clients are
properly limited, while still guaranteeing that at least one client
is always available to serve TCP connections on each interface.
- uses more descriptive names and removes one (ntcptarget) that
was no longer needed
- adds comments
(cherry picked from commit 924651f1d5e605cd186d03f4f7340bcc54d77cc2)
(cherry picked from commit 55a7a458e3)
tcp-clients settings could be exceeded in some cases by
creating more and more active TCP clients that are over
the set quota limit, which in the end could lead to a
DoS attack by e.g. exhaustion of file descriptors.
If TCP client we're closing went over the quota (so it's
not attached to a quota) mark it as mortal - so that it
will be destroyed and not set up to listen for new
connections - unless it's the last client for a specific
interface.
(cherry picked from commit f97131d21b97381cef72b971b157345c1f9b4115)
(cherry picked from commit 9689ffc485)
Witold KręcickiandMichał Kępień
Diego FronzaandOndřej Surý
Mark Andrews
Tinderbox User
Evan Hunt
Timothe LittandMark Andrews