Add resolvconf_path to end of struct ares_options with ARES_OPT_RESOLVCONF option
so on Unix-like systems a custom path can be specified. If no path is specified,
/etc/resolv.conf is used like normal.
Fix By: Sarat Addepalli @SirR4T
Fixes Bug: #220
Review By: Brad House @bradh352
For #164, I mentioned that it seemed like the IPv6 nameserver blacklist should apply to all OSes. In a mailing list post, @bradh352 agreed and suggested that I file a PR to make it so.
This moves the blacklist check from being Windows-specific to being a general feature of config_nameservers(), no matter the nameserver source. It also simplifies the ares_ipv6_server_blacklisted() implementation to not parse and re-parse the blacklisted IPv6 addresses from strings on every check. I think they're almost as easy to read as a sequence of hex bytes in an array initializer, and it's definitely less work on each trip through the code.
Fix By: Brad Spencer @b-spencer
PR: https://github.com/c-ares/c-ares/pull/193
Fix up a couple of problems with configuring whether c-ares rotates
between different name servers between requests.
Firstly, ares_save_options() returns (in *optmask) the value of
(channel->optmask & ARES_OPT_ROTATE), which doesn't necessarily
indicate whether the channel is or is not actually doing rotation.
This can be confusing/incorrect if:
- the channel was originally configured without ARES_OPT_ROTATE
(so it appears that the channel is not rotating)
- the /etc/resolv.conf file includes the 'rotate' option
(so the channel is actually performing rotation).
Secondly, it is not possible to reliably configure a channel
to not-rotate; leaving off ARES_OPT_ROTATE is not enough, since
a 'rotate' option in /etc/resolv.conf will turn it on again.
Therefore:
- add an ARES_OPT_NOROTATE optmask value to allow explicit
configuration of no-rotate behaviour
- in ares_save_options(), report the value of channel->rotate
as exactly one of (optmask & ARES_OPT_ROTATE) or
(optmask & ARES_OPT_NOROTATE).
In terms of back-compatibility:
- existing apps that set ARES_OPT_ROTATE will continue to rotate,
and to have ARES_OPT_ROTATE reported back from ares_save_options()
- existing apps that don't set ARES_OPT_ROTATE will continue to
use local config/defaults to decide whether to rotate, and will
now get ARES_OPT_ROTATE or ARES_OPT_NOROTATE reported back from
ares_save_options() rather than 0.
Commit 46bb820be3 ("ares_init_options: don't lose init failure")
changed init behaviour so that earlier errors in initialization
weren't lost. In particular, if the user passes in specific
options but they are not applied (e.g. because of an allocation
failure), that failure needs to be reported back to the user; this
also applies when duplicating a channel with ares_dup().
However, other initialization failures can be ignored and
overridden -- in particular, if init_by_resolv_conf() or
init_by_environment() fail, then falling back to default values
is OK.
So only preserve failures from the init_by_options() stage, not
from all initialization stages.
Fixes issue 60.
Modern Linux systems may have libnss_resolve from systemd as the
resolver, which is then configured in /etc/nsswitch.conf with
the "resolve" keyword rather than "dns".
Fixes#33
On Linux we can potentially use user and UTS namespaces to run a test
in a pseudo-container with:
- arbitrary filesystem (e.g. /etc/resolv.conf, /etc/nsswitch.conf, /etc/hosts)
- arbitrary hostname/domainname.
Include a first pass at the framework code to allow this, along with a
first test case that uses the container.
Different platforms will do different numbers of allocations
in the processing of a given API call; just check that the
return code is either success or ENOMEM, and free off any
returned state in the former case.
Also cope with ECONNREFUSED as well as ENOTFOUND.
- Initial nmake file based off library nmake file
- Cast socket call arguments to (char *)
- Use wrapper sclose() that maps to closesocket() or close()
- Build a config.h indicating presence of headers
- Conditionally include netdb.h
- Remove unnecessary include of sys/socket.h
- Force longer bitmask for allocation failure tracking
- Call WSAStartup() / WSACleanup() in main()
- Set TCP_NODELAY for mock server
- Turn on tests in AppVeyor build
- Make mock server listen on UDP + TCP in parallel.
- Test UDP->TCP fallback on truncation
- Test EDNS->no-EDNS fallback
- Test some environment init options
- Test nonsense reply
test: short response
Include tests of internal functions, based on the value of the
CARES_SYMBOL_HIDING macro; need to configure the library with
--disable-symbol-hiding to enable these tests.
The tests are written in C++11, using the GoogleTest and GoogleMock
frameworks. They have their own independent autoconf setup, so that
users of the library need not have a C++ compiler just to get c-ares
working (however, the test/configure.ac file does assume the use of
a shared top-level m4/ directory). However, this autoconf setup has
only been tested on Linux and OSX so far.
Run with "./arestest", or "./arestest -v" to see extra debug info.
The GoogleTest options for running specific tests are also
available (e.g. "./arestest --gtest_filter=*Live*").
The tests are nowhere near complete yet (currently hitting around
60% coverage as reported by gcov), but they do include examples
of a few different styles of testing:
- There are live tests (ares-test-live.cc), which assume that the
current machine has a valid DNS setup and connection to the
internet; these tests issue queries for real domains but don't
particularly check what gets returned. The tests will fail on
an offline machine.
- There a few mock tests (ares-test-mock.cc) that set up a fake DNS
server and inject its port into the c-ares library configuration.
These tests allow specific response messages to be crafted and
injected, and so are likely to be used for many more tests in
future.
- To make this generation/injection easier, the dns-proto.h file
includes C++ helper classes for building DNS packets.
- Other library entrypoints that don't require network activity
(e.g. ares_parse_*_reply) are tested directly.
- There are few tests of library-internal functions that are not
normally visible to API users (in ares-test-internal.cc).
- A couple of the tests use a helper method of the test fixture to
inject memory allocation failures, using the earlier change to the
library to allow override of malloc/realloc/free.
- There is also an entrypoint to allow Clang's libfuzzer to drive
the packet parsing code in ares_parse_*_reply, together with a
standalone wrapper for it (./aresfuzz) to allow use of afl-fuzz
for further fuzz testing.
Sarat Addepalli
Brad Spencer
David Drysdale