This pull request adds six flags to instruct the parser under various circumstances to skip parsing of the returned RR records so the raw data can be retrieved.
Fixes Bug: #686
Fix By: Erik Lax (@eriklax)
The previous build system allowed overwriting of CFLAGS/CPPFLAGS/CXXFLAGS on the make command line. Switch to using AM_CFLAGS/AM_CPPFLAGS/AM_CXXFLAGS when we set our own flags for building which ensures they are kept even when a user tries to override.
Fixes Bug: #694
Fix By: Brad House (@bradh352)
It appears as though we should never sanity check the RR name vs the question name as some DNS servers may return results for alias records.
Fixes Bug: #683
Fix By: Brad House (@bradh352)
* cmake: avoid warning about non-existing include dir
In the Debian build logs I noticed the following warning:
cc1: warning: /build/c-ares-1.25.0/test/include: No such file or directory [-Wmissing-include-dirs]
This happened because ${CMAKE_INSTALL_INCLUDEDIR} had been added to
caresinternal. I believe it has been copied from the "real" lib
where it's used in the INSTALL_INTERFACE context. But because
caresinternal is never installed we don't need that include here.
* cmake: drop CARES_TOPLEVEL_DIR variable
The CARES_TOPLEVEL_DIR variable is the same as the automatically
created PROJECT_SOURCE_DIR variable. Let's stick to the official
one. Also because it is already used at places where CARES_TOPLEVEL_DIR
is used as well.
Fix By: Gregor Jasny (@gjasny)
Completely rework the autotools build system, issues have cropped up due to the complexity and could cause issues on even semi-modern Linux systems (Ubuntu 20.04 for example).
Changes include:
Remove all curl/xc/cares m4 helper files, they go overboard on detections of functions and datatypes. Go back to more plain autoconf macros as they've come a long way over the years.
Use known systems and heuristics to determine datatypes for functions like send() and recv(), rather than the error prone detection which required thousands of permutations and might still get it wrong.
Remove unneeded configure arguments like --enable-debug or --enable-optimize, its more common for people to simply pass their own CFLAGS on the command line.
Only require CARES_STATICLIB definition on Windows static builds, its not necessary ever for other systems, even when hiding non-public symbols.
Remove some function and definition detections that were never used in c-ares
The test framework is now embedded into the toplevel configure system, there was no need to chain build the test system as it is never built externally to c-ares.
As a side-effect of the changes, a configure run completes in about 25% of the original time.
This has been tested on various Linux distributions (of varying age), FreeBSD, MacOS, Windows (via MSYS2 with Mingw), and Solaris10/11 (by @dfandrich), AIX 7.3 (by @dfandrich). It is not unlikely that this may have broken more esoteric or legacy systems, and we'll likely need to be ready to accept bug reports and patches, but it has removed over 10k lines of build system code. It is very likely any issues that crop up will add far fewer lines of code to fix such systems.
Fixes Bug: #670
Fix By: Brad House (@bradh352)
* get rid of clashes with curl namespace
* remove warnings due to deprecated functionality
* reorder some macro calls to get rid of warnings due to being called in the wrong order
Fix By: Brad House (@bradh352)
New test cases depend on internal symbols for calculating timeouts.
Disable those test features if symbol hiding is enabled.
Fixes Bug: #664
Fix By: Brad House (@bradh352)
When doing ares_gethostbyname() or ares_getaddrinfo() with AF_UNSPEC, if ares_cancel() was called after one address class was returned but before the other address class, it would return ARES_SUCCESS rather than ARES_ECANCELLED.
Test case has been added for this specific condition.
Fixes Bug: #662
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)
The parser for the sortlist has been rewritten to use the ares__buf_*() functions. This also resolves some known bugs in accepting invalid sortlist entries which should have caused parse failures.
Fixes Bug: #501
Fix By: Brad House (@bradh352)
As of c-ares 1.22.0, server timeouts were erroneously not incrementing server failures meaning the server in use wouldn't rotate. There was apparently never a test case for this condition.
This PR fixes the bug and adds a test case to ensure it behaves properly.
Fixes Bug: #650
Fix By: Brad House (@bradh352)
Some environments may send router advertisements on a link setting their link-local (fe80::/10) address as a valid DNS server to the remote system. This will cause a DNS entry to be created like `fe80::1%iface`, since all link-local network interfaces are technically part of the same /10 subnet, it must be told what interface to send packets through explicitly if there are multiple physical interfaces.
This PR adds support for the %iface modifier when setting DNS servers via `/etc/resolv.conf` as well as via `ares_set_servers_csv()`.
For MacOS and iOS it is assumed that libresolve will set the `sin6_scope_id` and should be supported, but my test systems don't seem to read the Router Advertisement for RDNSS link-local. Specifying the link-local dns server on MacOS via adig has been tested and confirmed working.
For Windows, this is similar to MacOS in that the system doesn't seem to honor the RDNSS RA, but specifying manually has been tested to work.
At this point, Android support does not exist.
Fixes Bug #462
Supersedes PR #463
Fix By: Brad House (@bradh352) and Serhii Purik (@sergvpurik)
Regression from c-ares 1.19.1, ARES_OPT_UDP_PORT and ARES_OPT_TCP_PORT are
specified from the user in host-byte order, but there was a regression that
caused it to be read as if it was network byte order.
Fixes Bug: #640
Reported By: @Flow86
Fix By: Brad House (@bradh352)
c-ares does not have any concept of thread-safety. It has always been 100% up to the implementor to ensure they never call c-ares from more than one thread at a time. This patch adds basic thread-safety support, which can be disabled at compile time if not desired. It uses a single recursive mutex per channel, which should be extremely quick when uncontested so overhead should be minimal.
Fixes Bug: #610
Also sets the stage to implement #611
Fix By: Brad House (@bradh352)
c-ares parses only antique version of options for timeout and number of retries from resolv.conf (`retrans` and `retry` are missing in modern documentation https://man7.org/linux/man-pages/man5/resolv.conf.5.html).
I add support of `attempts` and `timeout` options
Fix By: Ignat (@Kontakter)
When building for UWP (WindowsStore), additional headers are needed and some functions are not available. This also adds AppVeyor CI/CD support to catch these issues in the future.
Fix By: Deal (@halx99) and Brad House (@bradh352)
For historic reasons, we have users depending on ares_set_servers_*()
to return ARES_SUCCESS when passing no servers and actually *clear*
the server list. It appears they do this for test cases to simulate
DNS unavailable or similar. Presumably they could achieve the same
effect in other ways (point to localhost on a port that isn't in use).
But it seems like this might be wide-spread enough to cause headaches
so we just will document and test for this behavior, clearly it hasn't
caused "issues" for anyone with the old behavior.
See: https://github.com/nodejs/node/pull/50800
Fix By: Brad House (@bradh352)
This PR implements a query cache at the lowest possible level, the actual dns request and response messages. Only successful and `NXDOMAIN` responses are cached. The lowest TTL in the response message determines the cache validity period for the response, and is capped at the configuration value for `qcache_max_ttl`. For `NXDOMAIN` responses, the SOA record is evaluated.
For a query to match the cache, the opcode, flags, and each question's class, type, and name are all evaluated. This is to prevent matching a cached entry for a subtly different query (such as if the RD flag is set on one request and not another).
For things like ares_getaddrinfo() or ares_search() that may spawn multiple queries, each individual message received is cached rather than the overarching response. This makes it possible for one query in the sequence to be purged from the cache while others still return cached results which means there is no chance of ever returning stale data.
We have had a lot of user requests to return TTLs on all the various parsers like `ares_parse_caa_reply()`, and likely this is because they want to implement caching mechanisms of their own, thus this PR should solve those issues as well.
Due to the internal data structures we have these days, this PR is less than 500 lines of new code.
Fixes#608
Fix By: Brad House (@bradh352)
The retry timeout values were using a fixed calculation which could cause multiple simultaneous queries to timeout and retry at the exact same time. If a DNS server is throttling requests, this could cause the issue to never self-resolve due to all requests recurring at the same instance again.
This PR also creates a maximum timeout option to make sure the random value selected does not exceed this value.
Fix By: Ignat (@Kontakter)
This PR implements ares_reinit() to safely reload a channel's configuration even if there are existing queries. This function can be called when system configuration is detected to be changed, however since c-ares isn't thread aware, care must be taken to ensure no other c-ares calls are in progress at the time this function is called. Also, this function may update the open file descriptor list so care must also be taken to wake any event loops and reprocess the list of file descriptors.
Fixes Bug #301
Fix By: Brad House (@bradh352)
adig previously performed manual parsing of the DNS records. Now it can focus strictly on formatting of output data for printing. It simply iterates across the parsed DNS packet and queries for the RRs, parameters for each RR, and the datatypes for each parameter. adig will now automatically pick up new RRs from the c-ares library due to the dynamic nature.
The adig format also now more closely resembles that of BIND's `dig` output.
A few more helpers needed to be added to the c-ares library that were missing. There ware a couple of minor bugs and enhancements also needed.
Example:
```
./adig -t ANY www.google.com
; <<>> c-ares DiG 1.21.0 <<>> www.google.com
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: RCODE, id: 23913
;; flags: qr rd ra; QUERY: 1, ANSWER: 11, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags: 0; udp: 512
;; QUESTION SECTION:
;www.google.com. IN ANY
;; ANSWER SECTION:
www.google.com. 162 IN A 142.251.107.99
www.google.com. 162 IN A 142.251.107.105
www.google.com. 162 IN A 142.251.107.103
www.google.com. 162 IN A 142.251.107.147
www.google.com. 162 IN A 142.251.107.104
www.google.com. 162 IN A 142.251.107.106
www.google.com. 162 IN AAAA 2607:f8b0:400c:c32::93
www.google.com. 162 IN AAAA 2607:f8b0:400c:c32::69
www.google.com. 162 IN AAAA 2607:f8b0:400c:c32::68
www.google.com. 162 IN AAAA 2607:f8b0:400c:c32::6a
www.google.com. 21462 IN HTTPS 1 . alpn="h2,h3"
;; MSG SIZE rcvd: 276
```
Fix By: Brad House (@bradh352)
The OPT RR record has some seldom used options with a 16bit key and a binary value. The current parser and writer was not supporting this. This PR adds support. The same format is also used for SVCB/HTTPS records, so getting this in there is necessary to support that RR type.
Also, we split the Binary record format into BIN and BINP, where BINP is an indicator that the binary data is _likely_ printable and will guarantee a NULL terminator. This is helpful for those attempting to print RRs.
Fix By: Brad House (@bradh352)
As per #470, c-ares is missing a parser for the TLSA record format (RFC 6698). This PR introduces that parser.
Once the new parser interface becomes public and this PR is merged, then #470 can be closed.
Fix By: Brad House (@bradh352)
The `ares_dns_record_t` data structure created in the prior release is capable of holding a complete parsed DNS message and also provides all helpers in order to fill in the data structure. This PR adds write capabilities for this data structure to form a complete message and supports features such as DNS name compression as defined in RFC1035. Though this message writing capability goes further than c-ares internally needs, external users may find it useful ... and we may find it useful for test validation as well.
This also replaces the existing message writing code in `ares_create_query()`, as well rewriting the request message without EDNS in ares_process.c's `process_answer()`.
Fix By: Brad House (@bradh352)
Erik Lax
Brad House
Gregor Jasny
Christian Clauss
Ignat
Ignat