This is yet another step into unlocking some parts of the memory
contexts. All the regularly updated variables has been turned into
atomic types, so we can later remove the locks when updating various
counters.
Also unlock as much code as possible without breaking anything.
On 24-core machine, the tests would crash because we would run out of
the hazard pointers. We now adjust the number of hazard pointers to be
in the <128,256> interval based on the number of available cores.
Note: This is just a band-aid and needs a proper fix.
Previously, the applications using libisc would be able to override the
internal memory methods with own implementation. This was no longer
possible, but the extra level of indirection was not removed. This
commit removes the extra level of indirection for the memory methods and
the default_memalloc() and default_memfree().
The internal memory allocator had an extra code to keep a list of blocks
for small size allocation. This would help to reduce the interactions
with the system malloc as the memory would be already allocated from the
system, but there's an extra cost associated with that - all the
allocations/deallocations must be locked, effectively eliminating any
optimizations in the system allocator targeted at multi-threaded
applications. While the isc_mem API is still using locks pretty heavily,
this is a first step into reducing the memory allocation/deallocation
contention.
The <isc/readline.h> header provided a compatibility shim to use when
other non-GNU readline libraries are in use. The two places where
readline library is being used is nslookup and nsupdate, so the header
file has been moved to bin/dig directory and it's directly included from
bin/nsupdate.
This also conceals any readline headers exposed from the libisc headers.
This commit completes the support for DNS-over-HTTP(S) built on top of
nghttp2 and plugs it into the BIND. Support for both GET and POST
requests is present, as required by RFC8484.
Both encrypted (via TLS) and unencrypted HTTP/2 connections are
supported. The latter are mostly there for debugging/troubleshooting
purposes and for the means of encryption offloading to third-party
software (as might be desirable in some environments to simplify TLS
certificates management).
This commit includes work-in-progress implementation of
DNS-over-HTTP(S).
Server-side code remains mostly untested, and there is only support
for POST requests.
This commit resurrects the old TLS code from
8f73c70d23e26954165fd44ce5617a95f112bcff.
It also includes numerous stability fixes and support for
isc_nm_cancelread() for the TLS layer.
The code was resurrected to be used for DoH.
* Following the example set in 634bdfb16d8, the tlsdns netmgr
module now uses libuv and SSL primitives directly, rather than
opening a TLS socket which opens a TCP socket, as the previous
model was difficult to debug. Closes#2335.
* Remove the netmgr tls layer (we will have to re-add it for DoH)
* Add isc_tls API to wrap the OpenSSL SSL_CTX object into libisc
library; move the OpenSSL initialization/deinitialization from dstapi
needed for OpenSSL 1.0.x to the isc_tls_{initialize,destroy}()
* Add couple of new shims needed for OpenSSL 1.0.x
* When LibreSSL is used, require at least version 2.7.0 that
has the best OpenSSL 1.1.x compatibility and auto init/deinit
* Enforce OpenSSL 1.1.x usage on Windows
* Added a TLSDNS unit test and implemented a simple TLSDNS echo
server and client.
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
Add server-side TLS support to netmgr - that includes moving some of the
isc_nm_ functions from tcp.c to a wrapper in netmgr.c calling a proper
tcp or tls function, and a new isc_nm_listentls() function.
Add DoT support to tcpdns - isc_nm_listentlsdns().
this function sets the read timeout for the socket associated
with a netmgr handle and, if the timer is running, resets it.
for TCPDNS sockets it also sets the read timeout and resets the
timer on the outer TCP socket.
- isc_nm_tcpdnsconnect() sets up up an outgoing TCP DNS connection.
- isc_nm_tcpconnect(), _udpconnect() and _tcpdnsconnect() now take a
timeout argument to ensure connections time out and are correctly
cleaned up on failure.
- isc_nm_read() now supports UDP; it reads a single datagram and then
stops until the next time it's called.
- isc_nm_cancelread() now runs asynchronously to prevent assertion
failure if reading is interrupted by a non-network thread (e.g.
a timeout).
- isc_nm_cancelread() can now apply to UDP sockets.
- added shim code to support UDP connection in versions of libuv
prior to 1.27, when uv_udp_connect() was added
all these functions will be used to support outgoing queries in dig,
xfrin, dispatch, etc.
1. The isc__nm_tcp_send() and isc__nm_tcp_read() was not checking
whether the socket was still alive and scheduling reads/sends on
closed socket.
2. The isc_nm_read(), isc_nm_send() and isc_nm_resumeread() have been
changed to always return the error conditions via the callbacks, so
they always succeed. This applies to all protocols (UDP, TCP and
TCPDNS).
Attaching and detaching handle pointers will make it easier to
determine where and why reference counting errors have occurred.
A handle needs to be referenced more than once when multiple
asynchronous operations are in flight, so callers must now maintain
multiple handle pointers for each pending operation. For example,
ns_client objects now contain:
- reqhandle: held while waiting for a request callback (query,
notify, update)
- sendhandle: held while waiting for a send callback
- fetchhandle: held while waiting for a recursive fetch to
complete
- updatehandle: held while waiting for an update-forwarding
task to complete
control channel connection objects now contain:
- readhandle: held while waiting for a read callback
- sendhandle: held while waiting for a send callback
- cmdhandle: held while an rndc command is running
httpd connections contain:
- readhandle: held while waiting for a read callback
- sendhandle: held while waiting for a send callback
- rename isc_nmsocket_t->tcphandle to statichandle
- cancelread functions now take handles instead of sockets
- add a 'client' flag in socket objects, currently unused, to
indicate whether it is to be used as a client or server socket
While
if (isc_refcount_decrement() == 1) { // memory_order_release
isc_refcount_destroy(); // memory_order_acquire
...
}
is theoretically the most efficent in practice, using
memory_order_acq_rel produces the same code on x86_64 and doesn't
trigger tsan data races (which use a idealistic model) if
isc_refcount_destroy() is not called immediately. In fact
isc_refcount_destroy() could be removed if we didn't want
to check for the count being 0 when isc_refcount_destroy() is
called.
https://stackoverflow.com/questions/49112732/memory-order-in-shared-pointer-destructor
This commit updates and simplifies the checks for the readline support
in nslookup and nsupdate:
* Change the autoconf checks to pkg-config only, all supported
libraries have accompanying .pc files now.
* Add editline support in addition to libedit and GNU readline
* Add isc/readline.h shim header that defines dummy readline()
function when no readline library is available
When pk11_numbits() is passed a user provided input that contains all
zeroes (via crafted DNS message), it would crash with assertion
failure. Fix that by properly handling such input.
Created isc_refcount_decrement_expect macro to test conditionally
the return value to ensure it is in expected range. Converted
unchecked isc_refcount_decrement to use isc_refcount_decrement_expect.
Converted INSIST(isc_refcount_decrement()...) to isc_refcount_decrement_expect.
The stdatomic shims for non-C11 compilers (Windows, old gcc, ...) and
mutexatomic implemented only and minimal subset of the atomic types.
This commit adds 16-bit operations for Windows and all atomic types as
defined in standard.
the blackhole ACL was accidentally disabled with respect to client
queries during the netmgr conversion.
in order to make this work for TCP, it was necessary to add a return
code to the accept callback functions passed to isc_nm_listentcp() and
isc_nm_listentcpdns().
The isc_nm_cancelread() function cancels reading on a connected
socket and calls its read callback function with a 'result'
parameter of ISC_R_CANCELED.
the isc_nm_tcpconnect() function establishes a client connection via
TCP. once the connection is esablished, a callback function will be
called with a newly created network manager handle.
there is no need for a caller to reference-count socket objects.
they need tto be able tto close listener sockets (i.e., those
returned by isc_nm_listen{udp,tcp,tcpdns}), and an isc_nmsocket_close()
function has been added for that. other sockets are only accessed via
handles.
when built with "configure --enable-singletrace", named will produce
detailed query logging at the highest debug level for any query with
query ID zero.
this enables monitoring of the progress of a single query by specifying
the QID using "dig +qid=0". the "client" logging category should be set
to a low severity level to suppress logging of other queries. (the
chance of another query using QID=0 at the same time is only 1 in 2^16.)
"--enable-singletrace" turns on "--enable-querytrace" as well, so if the
logging severity is not lowered, all other queries will be logged
verbosely as well. compiling with either of these options will impair
query performance; they should only be turned on when testing or
troubleshooting.
Instead of using bind() and passing the listening socket to the children
threads using uv_export/uv_import use one thread that does the accepting,
and then passes the connected socket using uv_export/uv_import to a random
worker. The previous solution had thundering herd problems (all workers
waking up on one connection and trying to accept()), this one avoids this
and is simpler.
The tcp clients quota is simplified with isc_quota_attach_cb - a callback
is issued when the quota is available.
The rewrite of BIND 9 build system is a large work and cannot be reasonable
split into separate merge requests. Addition of the automake has a positive
effect on the readability and maintainability of the build system as it is more
declarative, it allows conditional and we are able to drop all of the custom
make code that BIND 9 developed over the years to overcome the deficiencies of
autoconf + custom Makefile.in files.
This squashed commit contains following changes:
- conversion (or rather fresh rewrite) of all Makefile.in files to Makefile.am
by using automake
- the libtool is now properly integrated with automake (the way we used it
was rather hackish as the only official way how to use libtool is via
automake
- the dynamic module loading was rewritten from a custom patchwork to libtool's
libltdl (which includes the patchwork to support module loading on different
systems internally)
- conversion of the unit test executor from kyua to automake parallel driver
- conversion of the system test executor from custom make/shell to automake
parallel driver
- The GSSAPI has been refactored, the custom SPNEGO on the basis that
all major KRB5/GSSAPI (mit-krb5, heimdal and Windows) implementations
support SPNEGO mechanism.
- The various defunct tests from bin/tests have been removed:
bin/tests/optional and bin/tests/pkcs11
- The text files generated from the MD files have been removed, the
MarkDown has been designed to be readable by both humans and computers
- The xsl header is now generated by a simple sed command instead of
perl helper
- The <irs/platform.h> header has been removed
- cleanups of configure.ac script to make it more simpler, addition of multiple
macros (there's still work to be done though)
- the tarball can now be prepared with `make dist`
- the system tests are partially able to run in oot build
Here's a list of unfinished work that needs to be completed in subsequent merge
requests:
- `make distcheck` doesn't yet work (because of system tests oot run is not yet
finished)
- documentation is not yet built, there's a different merge request with docbook
to sphinx-build rst conversion that needs to be rebased and adapted on top of
the automake
- msvc build is non functional yet and we need to decide whether we will just
cross-compile bind9 using mingw-w64 or fix the msvc build
- contributed dlz modules are not included neither in the autoconf nor automake
The pk11/constants.h header contained static CK_BYTE arrays and
we had to use #defines to pull only those we need. This commit
changes the constants to only define byte arrays with the content
and either use them directly or define the CK_BYTE arrays locally
where used.
