API Level 23 (Android 6) is the recommended target and often used
by other projects, like React Native. There are a lot of custom
Android platforms that may be stuck on old versions so we want to
make sure we support such old versions still.
Authored-By: Brad House (@bradh352)
GitHub actions supports running tests on various docker containers, move
Ubuntu 20.04 and Alpine tests to containers. Also move iOS testing to
GitHub actions since that runs on MacOS which is supported.
This should take additional load off of Cirrus-CI which consumes credits
like crazy. This leaves only FreeBSD and Linux ARM testing on Cirrus-CI.
Authored-By: Brad House (@bradh352)
TCP Fast Open (TFO) allows TCP connection establishment in 0-RTT when a
client and server have previously communicated. The SYN packet will also
contain the initial data packet from the client to the server. This
means there should be virtually no slowdown over UDP when both sides
support TCP FastOpen, which is unfortunately not always the case. For
instance, `1.1.1.1` appears to support TFO, however `8.8.8.8` does not.
This implementation supports Linux, Android, FreeBSD, MacOS, and iOS.
While Windows does have support for TCP FastOpen it does so via
completion APIs only, and that can't be used with polling APIs like used
by every other OS. We could implement it in the future if desired for
those using `ARES_OPT_EVENT_THREAD`, but it would probably require
adopting IOCP completely on Windows.
Sysctls are required to be set appropriately:
- Linux: `net.ipv4.tcp_fastopen`:
- `1` = client only (typically default)
- `2` = server only
- `3` = client and server
- MacOS: `net.inet.tcp.fastopen`
- `1` = client only
- `2` = server only
- `3` = client and server (typically default)
- FreeBSD: `net.inet.tcp.fastopen.server_enable` (boolean) and
`net.inet.tcp.fastopen.client_enable` (boolean)
This feature is always-on, when running on an OS with the capability
enabled. Though some middleboxes have impacted end-to-end TFO and caused
connectivity errors, all modern OSs perform automatic blackholing of IPs
that have issues with TFO. It is not expected this to cause any issues
in the modern day implementations.
This will also help with improving latency for future DoT and DoH
implementations.
Authored-By: Brad House (@bradh352)
Refactor some connection handling to reduce code duplication and to
unify the TCP and UDP codepaths a bit more. This will make some future
changes easier to make.
This also does some structure renaming to better conform with current
standards:
- `struct server_state` -> `ares_server_t`
- `struct server_connection` -> `ares_conn_t`
- `struct query` -> `ares_query_t`
Authored-by: Brad House (@bradh352)
DNS cookies are a simple form of learned mutual authentication supported
by most DNS server implementations these days and can help prevent DNS
Cache Poisoning attacks for clients and DNS amplification attacks for
servers.
Fixes#620
Fix By: Brad House (@bradh352)
We've been using a lot of time on Cirrus-CI and our credits run out
quickly. MacOS costs 15 compute credits vs 3 compute
credits for Linux. Move MacOS testing to GitHub Actions.
Fix By: Brad House (@bradh352)
c-ares is getting larger these days and we keep adding source files to
the same directory so it can be hard to differentiate core c-ares
implementation from library/utility functions. Lets make some
subdirectories to help with that and shuffle files around.
Fix By: Brad House (@bradh352)
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)
Watt-32 (https://www.watt-32.net/) support has been broken for a long
time. Patch c-ares to fix Watt-32 support and also gets rid of the
`WIN32` macro which adds confusion, only use `USE_WINSOCK` macro.
Add a CI/CD task to build c-ares on Windows using MSVC with Watt-32.
Fixes Issue: #780
Fix By: Brad House (@bradh352)
Automatically detect configuration changes and reload. On systems which
provide notification mechanisms, use those, otherwise fallback to
polling. When a system configuration change is detected, it
asynchronously applies the configuration in order to ensure it is a
non-blocking operation for any queries which may still be being
processed.
On Windows, however, changes aren't detected if a user manually
sets/changes the DNS servers on an interface, it doesn't appear there is
any mechanism capable of this. We are relying on
`NotifyIpInterfaceChange()` for notifications.
Fixes Issue: #613
Fix By: Brad House (@bradh352)
The DNS configuration for apple is stored in the system configuration
database. Apple does provide an emulated `/etc/resolv.conf` on MacOS
(but not iOS), it cannot, however, represent the entirety of the DNS
configuration. Alternatively, libresolv could be used to also retrieve
some system configuration, but it too is not capable of retrieving the
entirety of the DNS configuration.
Attempts to use the preferred public API of `SCDynamicStoreCreate()` and
friends yielded incomplete DNS information. Instead, that leaves some
apple "internal" symbols from `configd` that we need to access in order
to get the entire configuration. We can see that we're not the only ones
to do this as Google Chrome also does:
https://chromium.googlesource.com/chromium/src/+/HEAD/net/dns/dns_config_watcher_mac.cc
These internal functions are what what`libresolv` and `scutil` use to
retrieve the dns configuration. Since these symbols are not publicly
available, we will dynamically load the symbols from `libSystem` and
import the `dnsinfo.h` private header extracted from:
https://opensource.apple.com/source/configd/configd-1109.140.1/dnsinfo/dnsinfo.h
Fix By: Brad House (@bradh352)
GoogleTest should be unbundled. Google changed their guidance a few years back and modern versions of google test cannot build the bundling code file.
This PR also updates to use C++14 as is required by modern GoogleTest versions.
Fixes Bug: #506
Fix By: Brad House (@bradh352)
Brad House
Daniel Stenberg