The purpose of this PR is to hopefully make the private API of this set of routines less likely to need to be changed in a future release. While this is not a public API, it could become harder in the future to change usage as it becomes more widely used within c-ares.
Fix By: Brad House (@bradh352)
ares (and thus c-ares) was originally licensed under the 1989 MIT license text:
https://fedoraproject.org/wiki/Licensing:MIT#Old_Style_(no_advertising_without_permission)
This change updates the license to the modern MIT license as recognized here:
https://opensource.org/license/mit/
care has been taken to ensure correct attributions remain for the authors contained within the copyright headers, and all authors with attributions in the headers have been contacted for approval regarding the change. Any authors which were not able to be contacted, the original copyright maintains, luckily that exists in only a single file `ares_parse_caa_reply.c` at this time.
Please see PR #556 for the documented approvals by each contributor.
Fix By: Brad House (@bradh352)
The test framework was using 100ms timeout passed to select(), and not using ares_timeout() to calculate the actual recommended value based on the queries in queue. Using ares_timeout() tests the functionality of ares_timeout() itself and will provide more responsive results.
Fix By: Brad House (@bradh352)
As per #266, TCP queries are basically broken. If we get a partial reply, things just don't work, but unlike UDP, TCP may get fragmented and we need to properly handle that.
I've started creating a basic parser/buffer framework for c-ares for memory safety reasons, but it also helps for things like this where we shouldn't be manually tracking positions and fetching only a couple of bytes at a time from a socket. This parser/buffer will be expanded and used more in the future.
This also resolves#206 by allowing NULL to be specified for some socket callbacks so they will auto-route to the built-in c-ares functions.
Fixes: #206, #266
Fix By: Brad House (@bradh352)
The acountry utility required a third party DNSBL service from nerd.dk in order to operate. That service has been offline for about a year and there is no other comparable service offering. We are keeping the code in the repository as an example, but no longer building it.
Fixes: #537
Fix By: Brad House (@bradh352)
During ares_destroy(), any outstanding queries are terminated, however ares_getaddrinfo() had an ordering issue with status codes which in some circumstances could lead to a new query being enqueued rather than honoring the termination.
Fixes#532
Fix By: @Chilledheart and Brad House (@bradh352)
As per #541, when using AF_UNSPEC with ares_getaddrinfo() (and in turn with ares_gethostbynam()) if we receive a successful response for one address class, we should not allow the other address class to continue on with retries, just return the address class we have.
This will limit the overall query time to whatever timeout remains for the pending query for the other address class, it will not, however, terminate the other query as it may still prove to be successful (possibly coming in less than a millisecond later) and we'd want that result still. It just turns off additional error processing to get the result back quicker.
Fixes Bug: #541
Fix By: Brad House (@bradh352)
Add a new ARES_OPT_UDP_MAX_QUERIES option with udp_max_queries parameter that can be passed to ares_init_options(). This value defaults to 0 (unlimited) to maintain existing compatibility, any positive number will cause new UDP ephemeral ports to be created once the threshold is reached, we'll call these 'connections' even though its technically wrong for UDP.
Implementation Details:
* Each server entry in a channel now has a linked-list of connections/ports for udp and tcp. The first connection in the list is the one most likely to be eligible to accept new queries.
* Queries are now tracked by connection rather than by server.
* Every time a query is detached from a connection, the connection that it was attached to will be checked to see if it needs to be cleaned up.
* Insertion, lookup, and searching for connections has been implemented as O(1) complexity so the number of connections will not impact performance.
* Remove is_broken from the server, it appears it would be set and immediately unset, so must have been invalidated via a prior patch. A future patch should probably track consecutive server errors and de-prioritize such servers. The code right now will always try servers in the order of configuration, so a bad server in the list will always be tried and may rely on timeout logic to try the next.
* Various other cleanups to remove code duplication and for clarification.
Fixes Bug: #444
Fix By: Brad House (@bradh352)
A lot of time has passed since the original timeouts and retry counts were chosen. We have on and off issues reported due to this. Even on geostationary satellite links, latency is worst case around 1.5s. This PR changes the per-server timeout to 2s and the retry count lowered from 4 to 3.
Fix By: Brad House (@bradh352)
c-ares currently lacks modern data structures that can make coding easier and more efficient. This PR implements a new linked list, skip list (sorted linked list), and hashtable implementation that are easy to use and hard to misuse. Though these implementations use more memory allocations than the prior implementation, the ability to more rapidly iterate on the codebase is a bigger win than any marginal performance difference (which is unlikely to be visible, modern systems are much more powerful than when c-ares was initially created).
The data structure implementation favors readability and audit-ability over performance, however using the algorithmically correct data type for the purpose should offset any perceived losses.
The primary motivation for this PR is to facilitate future implementation for Issues #444, #135, #458, and possibly #301
A couple additional notes:
The ares_timeout() function is now O(1) complexity instead of O(n) due to the use of a skiplist.
Some obscure bugs were uncovered which were actually being incorrectly validated in the test cases. These have been addressed in this PR but are not explicitly discussed.
Fixed some dead code warnings in ares_rand for systems that don't need rc4
Fix By: Brad House (@bradh352)
As per https://man.openbsd.org/OpenBSD-5.1/resolv.conf.5 we should
support bracketed syntax for resolv.conf entries to contain an optional
port number.
We also need to utilize this format for configuration of MacOS
DNS servers as seen when using the Viscosity OpenVPN client, where
it starts a private DNS server listening on localhost on a non-standard
port.
Fix By: Brad House (@bradh352)
All files have their licence and copyright information clearly
identifiable. If not in the file header, they are set separately in
.reuse/dep5.
All used license texts are provided in LICENSES/
This commit adds instructions on how to use the WATCOM compiler to build c-ares. This was just tested on c-ares-1.19.1 and works well.
While going through the links for the C Runtime documentation for Windows systems, I discovered that all three of the KB articles that were linked are now nonexistent. This commit replaces KB94248 with the current replacement available on Microsoft's website, which also makes the other two KB articles obsolete.
Fix By: Douglas R. Reno (@renodr)
* Merged latest OpenBSD changes for inet_net_pton_ipv6() into c-ares.
* Always use our own IP conversion functions now, do not delegate to OS
so we can have consistency in testing and fuzzing.
* Removed bogus test cases that never should have passed.
* Add new test case for crash bug found.
Fix By: Brad House (@bradh352)
* segment random number generation into own file
* abstract random code to make it more modular so we can have multiple backends
* rand: add support for arc4random_buf() and also direct CARES_RANDOM_FILE reading
* autotools: fix detection of arc4random_buf
* rework initial rc4 seed for PRNG as last fallback
* rc4: more proper implementation, simplified for clarity
* clarifications
* CARES_RANDOM_FILE should always default to /dev/urandom
During cross-compilation, CARES_RANDOM_FILE may not be able to be appropriately
detected, therefore we should always set it to /dev/urandom and allow the
entity requesting compilation override the value. The code does appropriately
fall back if CARES_RANDOM_FILE cannot be opened.
* use set not option
As per #517 glibc allows a service/servname of "0" to be treated the
same as if NULL was provided. Also, add a sanity check to ensure
the port number is in range instead of a blind cast.
Fixes: #517
Fix By: Brad House (@bradh352)
When the condition channel->nservers < 1 holds, the function returns
prematurely, without deallocating query->tcpbuf. We rearrange the
check to be done prior to the allocations, avoiding the memory
leak. In this way, we also avoid unnecessary allocations if
channel->nservers < 1 holds.
Fix By: Nikolaos Chatzikonstantinou (@createyourpersonalaccount)
Following the README.md guidelines,
"Comments must be written in the old-style"
the comment is changed to the old style.
Fix By: Nikolaos Chatzikonstantinou (@createyourpersonalaccount)
strncasecmp on platforms that don't already have it is already #define'd to a private implementation. There is no need to have OS-specific logic. Also removes ares__strsplit.h as a header as ares_private.h already includes it.
Fix By: Nikolaos Chatzikonstantinou (@createyourpersonalaccount)
- Modify the Watcom Makefile for the source code reorganization (#352)
- Add *.map files into .gitignore
- Fix build errors with Watcom's builtin Windows SDK (which is rather
outdated). It's smart enough to understand Windows Vista, but doesn't
have PMIB_UNICASTIPADDRESS_TABLE or MIB_IPFORWARD_ROW2.
It may be possible to use a different Windows SDK with the Watcom
compiler, such as the most recent Windows 10 SDK. Alternatively the SDK
in OpenWatcom 2.0 (which is in development) should fix this.
I have no problems testing this Makefile prior to releases, just give me
a ping.
Tested with Windows Vista, Windows 7, and Windows 10 using 'adig',
'acountry', and 'ahost'. This also seems to work on Windows XP, though
this is likely due to the compiler in use.
Fix By: Douglas R. Reno (@renodr)
Fixes Bug: #352
In some conditions Windows might try to use a stack address that has gone out of scope when determining where to read the hosts data from for file lookups.
Fix By: @Chilledheart
Brad House
Sam Morris
Jérôme Duval
Daniel Stenberg
Alexey A Tikhonov
Ben Noordhuis
Tim Wojtulewicz
Douglas R. Reno
Gregor Jasny
lifenjoiner
Nikolaos Chatzikonstantinou
Yijie Ma
Jay Freeman (saurik)
Chilledheart