7b9c8b9781
This is a part of the works that intends to make the netmgr stable,
testable, maintainable and tested. It contains a numerous changes to
the netmgr code and unfortunately, it was not possible to split this
into smaller chunks as the work here needs to be committed as a complete
works.
NOTE: There's a quite a lot of duplicated code between udp.c, tcp.c and
tcpdns.c and it should be a subject to refactoring in the future.
The changes that are included in this commit are listed here
(extensively, but not exclusively):
* The netmgr_test unit test was split into individual tests (udp_test,
tcp_test, tcpdns_test and newly added tcp_quota_test)
* The udp_test and tcp_test has been extended to allow programatic
failures from the libuv API. Unfortunately, we can't use cmocka
mock() and will_return(), so we emulate the behaviour with #define and
including the netmgr/{udp,tcp}.c source file directly.
* The netievents that we put on the nm queue have variable number of
members, out of these the isc_nmsocket_t and isc_nmhandle_t always
needs to be attached before enqueueing the netievent_<foo> and
detached after we have called the isc_nm_async_<foo> to ensure that
the socket (handle) doesn't disappear between scheduling the event and
actually executing the event.
* Cancelling the in-flight TCP connection using libuv requires to call
uv_close() on the original uv_tcp_t handle which just breaks too many
assumptions we have in the netmgr code. Instead of using uv_timer for
TCP connection timeouts, we use platform specific socket option.
* Fix the synchronization between {nm,async}_{listentcp,tcpconnect}
When isc_nm_listentcp() or isc_nm_tcpconnect() is called it was
waiting for socket to either end up with error (that path was fine) or
to be listening or connected using condition variable and mutex.
Several things could happen:
0. everything is ok
1. the waiting thread would miss the SIGNAL() - because the enqueued
event would be processed faster than we could start WAIT()ing.
In case the operation would end up with error, it would be ok, as
the error variable would be unchanged.
2. the waiting thread miss the sock->{connected,listening} = `true`
would be set to `false` in the tcp_{listen,connect}close_cb() as
the connection would be so short lived that the socket would be
closed before we could even start WAIT()ing
* The tcpdns has been converted to using libuv directly. Previously,
the tcpdns protocol used tcp protocol from netmgr, this proved to be
very complicated to understand, fix and make changes to. The new
tcpdns protocol is modeled in a similar way how tcp netmgr protocol.
Closes: #2194, #2283, #2318, #2266, #2034, #1920
* The tcp and tcpdns is now not using isc_uv_import/isc_uv_export to
pass accepted TCP sockets between netthreads, but instead (similar to
UDP) uses per netthread uv_loop listener. This greatly reduces the
complexity as the socket is always run in the associated nm and uv
loops, and we are also not touching the libuv internals.
There's an unfortunate side effect though, the new code requires
support for load-balanced sockets from the operating system for both
UDP and TCP (see #2137). If the operating system doesn't support the
load balanced sockets (either SO_REUSEPORT on Linux or SO_REUSEPORT_LB
on FreeBSD 12+), the number of netthreads is limited to 1.
* The netmgr has now two debugging #ifdefs:
1. Already existing NETMGR_TRACE prints any dangling nmsockets and
nmhandles before triggering assertion failure. This options would
reduce performance when enabled, but in theory, it could be enabled
on low-performance systems.
2. New NETMGR_TRACE_VERBOSE option has been added that enables
extensive netmgr logging that allows the software engineer to
precisely track any attach/detach operations on the nmsockets and
nmhandles. This is not suitable for any kind of production
machine, only for debugging.
* The tlsdns netmgr protocol has been split from the tcpdns and it still
uses the old method of stacking the netmgr boxes on top of each other.
We will have to refactor the tlsdns netmgr protocol to use the same
approach - build the stack using only libuv and openssl.
* Limit but not assert the tcp buffer size in tcp_alloc_cb
Closes: #2061
(cherry picked from commit
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| .gitlab/issue_templates | ||
| bin | ||
| cocci | ||
| conftools/perllib/dnsconf | ||
| contrib | ||
| doc | ||
| docutil | ||
| fuzz | ||
| lib | ||
| m4 | ||
| make | ||
| unit | ||
| util | ||
| win32utils | ||
| .clang-format | ||
| .clang-format.headers | ||
| .dir-locals.el | ||
| .gitattributes | ||
| .gitignore | ||
| .gitlab-ci.yml | ||
| .pylintrc | ||
| .uncrustify.cfg | ||
| aclocal.m4 | ||
| autogen.sh | ||
| bind.keys | ||
| bind.keys.h | ||
| CHANGES | ||
| CODE_OF_CONDUCT | ||
| CODE_OF_CONDUCT.md | ||
| config.guess | ||
| config.h.in | ||
| config.h.win32 | ||
| config.sub | ||
| config.threads.in | ||
| configure | ||
| configure.ac | ||
| CONTRIBUTING | ||
| CONTRIBUTING.md | ||
| COPYRIGHT | ||
| dangerfile.py | ||
| HISTORY | ||
| HISTORY.md | ||
| install-sh | ||
| Kyuafile | ||
| LICENSE | ||
| ltmain.sh | ||
| Makefile.in | ||
| mkinstalldirs | ||
| OPTIONS | ||
| OPTIONS.md | ||
| PLATFORMS | ||
| PLATFORMS.md | ||
| README | ||
| README.md | ||
| version | ||
BIND 9
Contents
- Introduction
- Reporting bugs and getting help
- Contributing to BIND
- BIND 9.16 features
- Building BIND
- macOS
- Dependencies
- Compile-time options
- Automated testing
- Documentation
- Change log
- Acknowledgments
Introduction
BIND (Berkeley Internet Name Domain) is a complete, highly portable implementation of the DNS (Domain Name System) protocol.
The BIND name server, named, is able to serve as an authoritative name
server, recursive resolver, DNS forwarder, or all three simultaneously. It
implements views for split-horizon DNS, automatic DNSSEC zone signing and
key management, catalog zones to facilitate provisioning of zone data
throughout a name server constellation, response policy zones (RPZ) to
protect clients from malicious data, response rate limiting (RRL) and
recursive query limits to reduce distributed denial of service attacks,
and many other advanced DNS features. BIND also includes a suite of
administrative tools, including the dig and delv DNS lookup tools,
nsupdate for dynamic DNS zone updates, rndc for remote name server
administration, and more.
BIND 9 began as a complete re-write of the BIND architecture that was used in versions 4 and 8. Internet Systems Consortium (https://www.isc.org), a 501(c)(3) public benefit corporation dedicated to providing software and services in support of the Internet infrastructure, developed BIND 9 and is responsible for its ongoing maintenance and improvement. BIND is open source software licensed under the terms of the Mozilla Public License, version 2.0.
For a summary of features introduced in past major releases of BIND, see the file HISTORY.
For a detailed list of changes made throughout the history of BIND 9, see the file CHANGES. See below for details on the CHANGES file format.
For up-to-date versions and release notes, see https://www.isc.org/download/.
For information about supported platforms, see PLATFORMS.
Reporting bugs and getting help
To report non-security-sensitive bugs or request new features, you may open an Issue in the BIND 9 project on the ISC GitLab server at https://gitlab.isc.org/isc-projects/bind9.
Please note that, unless you explicitly mark the newly created Issue as
"confidential", it will be publicly readable. Please do not include any
information in bug reports that you consider to be confidential unless
the issue has been marked as such. In particular, if submitting the
contents of your configuration file in a non-confidential Issue, it is
advisable to obscure key secrets: this can be done automatically by
using named-checkconf -px.
If the bug you are reporting is a potential security issue, such as an
assertion failure or other crash in named, please do NOT use GitLab to
report it. Instead, send mail to
security-officer@isc.org using our
OpenPGP key to secure your message. (Information about OpenPGP and links
to our key can be found at
https://www.isc.org/pgpkey.) Please do not
discuss the bug on any public mailing list.
For a general overview of ISC security policies, read the Knowledge Base article at https://kb.isc.org/docs/aa-00861.
Professional support and training for BIND are available from ISC at https://www.isc.org/support.
To join the BIND Users mailing list, or view the archives, visit https://lists.isc.org/mailman/listinfo/bind-users.
If you're planning on making changes to the BIND 9 source code, you may also want to join the BIND Workers mailing list, at https://lists.isc.org/mailman/listinfo/bind-workers.
Contributing to BIND
ISC maintains a public git repository for BIND; details can be found at http://www.isc.org/git/.
Information for BIND contributors can be found in the following files:
- General information: CONTRIBUTING.md
- Code of Conduct: CODE_OF_CONDUCT.md
- BIND 9 code style: doc/dev/style.md
- BIND architecture and developer guide: doc/dev/dev.md
Patches for BIND may be submitted as merge requests in the ISC GitLab server at at https://gitlab.isc.org/isc-projects/bind9/merge_requests.
By default, external contributors don't have ability to fork BIND in the GitLab server, but if you wish to contribute code to BIND, you may request permission to do so. Thereafter, you can create git branches and directly submit requests that they be reviewed and merged.
If you prefer, you may also submit code by opening a
GitLab Issue and
including your patch as an attachment, preferably generated by
git format-patch.
BIND 9.16 features
BIND 9.16 is the current stable branch of BIND 9. It includes all changes from the 9.15 development branch, updating the previous stable branch, 9.14. New features include:
- New
dnssec-policystatement to configure a key and signing policy for zones, enabling automatic key regeneration and rollover. - New network manager based on
libuv. - Added support for the new GeoIP2 geolocation API,
libmaxminddb. - Improved DNSSEC trust anchor configuration using the
trust-anchorsstatement, permitting configuration of trust anchors in DS as well as DNSKEY format. - YAML output for
dig,mdig, anddelv.
Building BIND
Minimally, BIND requires a UNIX or Linux system with an ANSI C compiler,
basic POSIX support, and a 64-bit integer type. BIND also requires the
libuv asynchronous I/O library, and a cryptography provider library
such as OpenSSL or a hardware service module supporting PKCS#11. On
Linux, BIND requires the libcap library to set process privileges,
though this requirement can be overridden by disabling capability
support at compile time. See Compile-time options below
for details on other libraries that may be required to support
optional features.
Successful builds have been observed on many versions of Linux and UNIX, including RHEL/CentOS, Fedora, Debian, Ubuntu, SLES, openSUSE, Slackware, Alpine, FreeBSD, NetBSD, OpenBSD, macOS, Solaris, OpenIndiana, OmniOS CE, HP-UX, and OpenWRT.
BIND is also available for Windows Server 2012 R2 and higher. See
win32utils/build.txt for details on building for Windows
systems.
To build on a UNIX or Linux system, use:
$ ./configure
$ make
If you're planning on making changes to the BIND 9 source, you should run
make depend. If you're using Emacs, you might find make tags helpful.
Several environment variables that can be set before running configure will
affect compilation. Significant ones are:
| Variable | Description |
|---|---|
CC |
The C compiler to use. configure tries to figure out the right one for supported systems. |
CFLAGS |
C compiler flags. Defaults to include -g and/or -O2 as supported by the compiler. Please include '-g' if you need to set CFLAGS. |
STD_CINCLUDES |
System header file directories. Can be used to specify where add-on thread or IPv6 support is, for example. Defaults to empty string. |
STD_CDEFINES |
Any additional preprocessor symbols you want defined. Defaults to empty string. For a list of possible settings, see the file OPTIONS. |
LDFLAGS |
Linker flags. Defaults to empty string. |
BUILD_CC |
Needed when cross-compiling: the native C compiler to use when building for the target system. |
BUILD_CFLAGS |
CFLAGS for the target system during cross-compiling. |
BUILD_CPPFLAGS |
CPPFLAGS for the target system during cross-compiling. |
BUILD_LDFLAGS |
LDFLAGS for the target system during cross-compiling. |
BUILD_LIBS |
LIBS for the target system during cross-compiling. |
Additional environment variables affecting the build are listed at the
end of the configure help text, which can be obtained by running the
command:
$ ./configure --help
macOS
Building on macOS assumes that the "Command Tools for Xcode" is installed.
This can be downloaded from
https://developer.apple.com/download/more/
or, if you have Xcode already installed, you can run xcode-select --install. (Note that an Apple ID may be required to access the download
page.)
Dependencies
Portions of BIND that are written in Python, including
dnssec-keymgr, dnssec-coverage, dnssec-checkds, and some of the
system tests, require the argparse, ply and distutils.core modules
to be available.
argparse is a standard module as of Python 2.7 and Python 3.2.
ply is available from https://pypi.python.org/pypi/ply.
distutils.core is required for installation.
Compile-time options
To see a full list of configuration options, run configure --help.
To build shared libraries, specify --with-libtool on the configure
command line.
For the server to support DNSSEC, you need to build it with crypto support.
To use OpenSSL, you should have OpenSSL 1.0.2e or newer installed. If the
OpenSSL library is installed in a nonstandard location, specify the prefix
using --with-openssl=<PREFIX> on the configure command line. To use a
PKCS#11 hardware service module for cryptographic operations, specify the
path to the PKCS#11 provider library using --with-pkcs11=<PREFIX>, and
configure BIND with --enable-native-pkcs11.
To support the HTTP statistics channel, the server must be linked with at
least one of the following libraries: libxml2
http://xmlsoft.org or json-c
https://github.com/json-c/json-c.
If these are installed at a nonstandard location, then:
- for
libxml2, specify the prefix using--with-libxml2=/prefix, - for
json-c, adjustPKG_CONFIG_PATH.
To support compression on the HTTP statistics channel, the server must be
linked against libzlib. If this is installed in a nonstandard location,
specify the prefix using --with-zlib=/prefix.
To support storing configuration data for runtime-added zones in an LMDB
database, the server must be linked with liblmdb. If this is installed in a
nonstandard location, specify the prefix using with-lmdb=/prefix.
To support MaxMind GeoIP2 location-based ACLs, the server must be linked
with libmaxminddb. This is turned on by default if the library is
found; if the library is installed in a nonstandard location,
specify the prefix using --with-maxminddb=/prefix. GeoIP2 support
can be switched off with --disable-geoip.
For DNSTAP packet logging, you must have installed libfstrm
https://github.com/farsightsec/fstrm
and libprotobuf-c
https://developers.google.com/protocol-buffers,
and BIND must be configured with --enable-dnstap.
Certain compiled-in constants and default settings can be decreased to
values better suited to small machines, e.g. OpenWRT boxes, by specifying
--with-tuning=small on the configure command line. This will decrease
memory usage by using smaller structures, but will degrade performance.
On Linux, process capabilities are managed in user space using
the libcap library, which can be installed on most Linux systems via
the libcap-dev or libcap-devel package. Process capability support can
also be disabled by configuring with --disable-linux-caps.
On some platforms it is necessary to explicitly request large file support
to handle files bigger than 2GB. This can be done by using
--enable-largefile on the configure command line.
Support for the "fixed" rrset-order option can be enabled or disabled by
specifying --enable-fixed-rrset or --disable-fixed-rrset on the
configure command line. By default, fixed rrset-order is disabled to
reduce memory footprint.
The --enable-querytrace option causes named to log every step of
processing every query. This should only be enabled when debugging, because
it has a significant negative impact on query performance.
make install will install named and the various BIND 9 libraries. By
default, installation is into /usr/local, but this can be changed with the
--prefix option when running configure.
You may specify the option --sysconfdir to set the directory where
configuration files like named.conf go by default, and --localstatedir
to set the default parent directory of run/named.pid. --sysconfdir
defaults to $prefix/etc and --localstatedir defaults to $prefix/var.
Automated testing
A system test suite can be run with make test. The system tests require
you to configure a set of virtual IP addresses on your system (this allows
multiple servers to run locally and communicate with one another). These
IP addresses can be configured by running the command
bin/tests/system/ifconfig.sh up as root.
Some tests require Perl and the Net::DNS and/or IO::Socket::INET6 modules,
and will be skipped if these are not available. Some tests require Python
and the dnspython module and will be skipped if these are not available.
See bin/tests/system/README for further details.
Unit tests are implemented using the CMocka unit testing framework.
To build them, use configure --with-cmocka. Execution of tests is done
by the Kyua test execution engine; if the
kyua command is available, then unit tests can be run via make test
or make unit.
Documentation
The BIND 9 Administrator Reference Manual is included with the source
distribution, in DocBook XML, HTML, and PDF format, in the doc/arm
directory.
Some of the programs in the BIND 9 distribution have man pages in their
directories. In particular, the command line options of named are
documented in bin/named/named.8.
Frequently (and not-so-frequently) asked questions and their answers can be found in the ISC Knowledge Base at https://kb.isc.org.
Additional information on various subjects can be found in other
README files throughout the source tree.
Change log
A detailed list of all changes that have been made throughout the development BIND 9 is included in the file CHANGES, with the most recent changes listed first. Change notes include tags indicating the category of the change that was made; these categories are:
| Category | Description |
|---|---|
| [func] | New feature |
| [bug] | General bug fix |
| [security] | Fix for a significant security flaw |
| [experimental] | Used for new features when the syntax or other aspects of the design are still in flux and may change |
| [port] | Portability enhancement |
| [maint] | Updates to built-in data such as root server addresses and keys |
| [tuning] | Changes to built-in configuration defaults and constants to improve performance |
| [performance] | Other changes to improve server performance |
| [protocol] | Updates to the DNS protocol such as new RR types |
| [test] | Changes to the automatic tests, not affecting server functionality |
| [cleanup] | Minor corrections and refactoring |
| [doc] | Documentation |
| [contrib] | Changes to the contributed tools and libraries in the 'contrib' subdirectory |
| [placeholder] | Used in the main development branch to reserve change numbers for use in other branches, e.g., when fixing a bug that only exists in older releases |
In general, [func] and [experimental] tags will only appear in new-feature releases (i.e., those with version numbers ending in zero). Some new functionality may be backported to older releases on a case-by-case basis. All other change types may be applied to all currently-supported releases.
Bug report identifiers
Most notes in the CHANGES file include a reference to a bug report or
issue number. Prior to 2018, these were usually of the form [RT #NNN]
and referred to entries in the "bind9-bugs" RT database, which was not open
to the public. More recent entries use the form [GL #NNN] or, less often,
[GL !NNN], which, respectively, refer to issues or merge requests in the
GitLab database. Most of these are publicly readable, unless they include
information which is confidential or security sensitive.
To look up a GitLab issue by its number, use the URL https://gitlab.isc.org/isc-projects/bind9/issues/NNN. To look up a merge request, use https://gitlab.isc.org/isc-projects/bind9/merge_requests/NNN.
In rare cases, an issue or merge request number may be followed with the letter "P". This indicates that the information is in the private ISC GitLab instance, which is not visible to the public.
Acknowledgments
-
The original development of BIND 9 was underwritten by the following organizations:
Sun Microsystems, Inc. Hewlett Packard Compaq Computer Corporation IBM Process Software Corporation Silicon Graphics, Inc. Network Associates, Inc. U.S. Defense Information Systems Agency USENIX Association Stichting NLnet - NLnet Foundation Nominum, Inc. -
This product includes software developed by the OpenSSL Project for use in the OpenSSL Toolkit. http://www.OpenSSL.org/
-
This product includes cryptographic software written by Eric Young (eay@cryptsoft.com)
-
This product includes software written by Tim Hudson (tjh@cryptsoft.com)