We've had reports of user-after-free type crashes in Windows cleanup
code for the Event Thread. In evaluating the code, it appeared there
were some memory leaks on per-connection handles that may have remained
open during shutdown, while trying to resolve that it became apparent
the methodology chosen may not have been the right one for interfacing
with the Windows AFD system as stability issues were seen during this
debugging process.
Since this system is completely undocumented, there was no clear
resolution path other than to switch to the *other* methodology which
involves directly opening `\Device\Afd`, rather than spawning a "peer
socket" to use to queue AFD operations.
The original methodology chosen more closely resembled what is employed
by [libuv](https://github.com/libuv/libuv) and given its widespread use
was the reason it was used. The new methodology more closely resembles
[wepoll](https://github.com/piscisaureus/wepoll).
Its not clear if there are any scalability or performance advantages or
disadvantages for either method. They both seem like different ways to
do the same thing, but this current way does seem more stable.
Fixes#798
Fix By: Brad House (@bradh352)
AppVeyor has gotten progressively slower over the last year or so. Move
some Windows builds to GitHub actions which is considerably faster.
Fix By: Brad House (@bradh352)
On some broken MacOS SDK versions, if HAVE_UNISTD_H is defined, it
must be defined to 1, otherwise it will cause build errors. Autotools
always defines to 1, but CMake doesn't.
Fixes Issue: #787
Fix By: Brad House (@bradh352)
The query cache wasn't properly flushing on server list changes
and was attempting to flush even when the server list didn't
actually change.
Fix By: Brad House (@bradh352)
Due to a logic flaw dns name compression writing was not properly implemented
which would result in the name prefix not being written for a partial match.
Fixes Bug: #757
Fix By: Brad House (@bradh352)
The DNS message protocol when using non-binary strings needs to be in
the ASCII printable range. The function prototype does elude to this
but it was not actually validating the string was in anyway valid and
could be used. DNS parsing will now fail if an expected string isn't
an ASCII string.
Fixes Issue: #769
Fix By: Brad House (@bradh352)
salen validation should be greater than or equal to the required
storage size. Its not uncommon to use `struct sockaddr_storage` in
modern code which is definitely larger than `struct sockaddr_in` and
on some systems even larger than `struct sockaddr_in6`.
Fixes Issue: #752
Fix By: Brad House (@bradh352)
If an invalid event thread system was provided, it would crash during cleanup due to a NULL pointer dereference.
Fixes Issue: #749
Fix By: Brad House (@bradh352)
There is a missing break statement in the case that timeout_ms >= 0
leading to a possible infinite loop.
Fixes Issue: #742
Fix By: Brad House (@bradh352)
If initializing using default settings fails, there may be a memory leak of
search domains that were set by system configuration.
Fixes Issue: #724
Fix By: Brad House (@bradh352)
Since acountry cannot be restored due to nerd.dk being decommissioned,
we should completely remove the manpage and source. This also
will resolve issue #718.
Fixes Issue: #718
Fix By: Brad House (@bradh352)
Hello, I work on an application for Microsoft which uses c-ares to
perform DNS lookups. We have made some minor changes to the library over
time, and would like to contribute these back to the project in case
they are useful more widely. This PR adds a new channel init flag,
described below.
Please let me know if I can include any more information to make this PR
better/easier for you to review. Thanks!
**Summary**
When initializing a channel with `ares_init_options()`, if there are no
nameservers available (because `ARES_OPT_SERVERS` is not used and
`/etc/resolv.conf` is either empty or not available) then a default
local named server will be added to the channel.
However in some applications a local named server will never be
available. In this case, all subsequent queries on the channel will
fail.
If we know this ahead of time, then it may be preferred to fail channel
initialization directly rather than wait for the queries to fail. This
gives better visibility, since we know that the failure is due to
missing servers rather than something going wrong with the queries.
This PR adds a new flag `ARES_FLAG_NO_DFLT_SVR`, to indicate that a
default local named server should not be added to a channel in this
scenario. Instead, a new error `ARES_EINITNOSERVER` is returned and
initialization fails.
**Testing**
I have added 2 new FV tests:
- `ContainerNoDfltSvrEmptyInit` to test that initialization fails when
no nameservers are available and the flag is set.
- `ContainerNoDfltSvrFullInit` to test that initialization still
succeeds when the flag is set but other nameservers are available.
Existing FVs are all passing.
**Documentation**
I have had a go at manually updating the docs to describe the new
flag/error, but couldn't see any contributing guidance about testing
this. Please let me know if you'd like anything more here.
---------
Fix By: Oliver Welsh (@oliverwelsh)
Add a function to request the number of active queries from an ares
channel. This will return the number of inflight requests to dns
servers. Some functions like `ares_getaddrinfo()` when using `AF_UNSPEC`
may enqueue multiple queries which will be reflected in this count.
In the future, if we implement support for queuing (e.g. for throttling
purposes), and/or implement support for tracking user-requested queries
(e.g. for cancelation), we can provide additional functions for
inspecting those queues.
Fix By: Brad House (@bradh352)
ares__strsplit provides a newly allocated buffer, so suffix list in
line variable isn't referenced anymore. Related ares_free seems to
have gone missing during refactoring made in #594
Fix By: Vojtěch Vobr (@vojtechvobr)
It may be useful to wait for the queue to be empty under certain conditions (mainly test cases), expose a function to efficiently do this and rework test cases to use it.
Fix By: Brad House (@bradh352)
CMake was unconditionally setting output locations globally, but
it should not do that if it is not the top-level project (e.g.
during chain building). Detect this fact and only set the output
location when top level.
Fixes Issue: #708
Fix By: Anthony Alayo (@anthonyalayo)
In 2020, it was agreed this is optimal maximum size and all
major server software was updated to reflect this.
see https://www.dnsflagday.net/2020/#faq
Fix By: Cristian Rodríguez (@crrodriguez)
Brad House
Gregor Jasny
Volker Schlecht
Faraz
Oliver Welsh
Vojtěch Vobr
Cheng Zhao
Cristian Rodríguez