1 Changelog for the c-ares project
3 * November 23, 2009 (Yang Tse)
4 - Changed naming convention for c-ares libraries built with MSVC, details
5 and build instructions provided in README.msvc file.
7 * November 22, 2009 (Yang Tse)
8 - Jakub Hrozek fixed more function prototypes in man pages to sync them
9 with the ones declared in ares.h
11 - Jakub Hrozek renamed addrttl and addr6ttl structs to ares_addrttl and
12 ares_addr6ttl in order to prevent name space pollution, along with
13 necessary changes to code base and man pages.This change does not break
14 ABI, there is no need to recompile existing applications. But existing
15 applications using these structs with the old name will need source code
16 adjustments when recompiled using c-ares 1.6.1.
18 * November 21, 2009 (Yang Tse)
19 - Added manifest stuff to Makefile.msvc.
21 * November 20, 2009 (Yang Tse)
22 - Fixed several function prototypes in man pages that were out of sync
23 with the ones declared in ares.h. Added ares_free_data() along with
24 man page. Updated ares_parse_srv_reply() and ares_parse_txt_reply()
25 with changes from Jakub Hrozek making these now return linked lists
26 instead of arrays, and merging the ares_free_data() adjustments.
28 * November 10, 2009 (Yang Tse)
29 - Updated MSVC 6.0 project files to match settings from Makefile.msvc.
31 * November 9, 2009 (Yang Tse)
32 - Makefile.msvc is now the reference method to build c-ares and sample
33 programs with any MSVC compiler or MS Visual Studio version. If no
34 option or target are specified it builds dynamic and static c-ares
35 libraries in debug and release flavours and also builds all sample
36 programs using each of the different c-ares libraries.
38 * November 2, 2009 (Yang Tse)
39 - Renamed c-ares setup.h to ares_setup.h
41 * October 31, 2009 (Yang Tse)
42 - Symbol hiding configure options are named now --enable-symbol-hiding
43 and --disable-symbol-hiding in an attempt to make them less ambiguous.
45 * October 30, 2009 (Yang Tse)
46 - Many fixes for ares_parse_txt_reply()
48 * October 29, 2009 (Daniel Stenberg)
49 - Jakub Hrozek added ares_parse_txt_reply() for TXT parsing
51 * October 29, 2009 (Yang Tse)
52 - Updated MSVC 6.0 workspace and project files that allows building
53 dynamic and static c-ares libraries in debug and release flavours.
54 Additionally each of the three sample programs is built against
55 each of the four possible c-ares libraries, generating all this
56 a total number of 12 executables and 4 libraries.
58 * October 28, 2009 (Yang Tse)
59 - Initial step towards the ability to reduce c-ares exported symbols
60 when built as a shared library based on the 'visibility' attribute
61 for GNUC and Intel compilers and based on __global for Sun compilers,
62 taking also in account __declspec function decoration for Win32 and
65 * October 27, 2009 (Yang Tse)
66 - Fixed Pelles C Win32 target compilation issues.
68 * October 23, 2009 (Yang Tse)
69 - John Engelhart noticed an unreleased problem relative to a duplicate
70 ARES_ECANCELLED error code value and missing error code description.
72 * October 7, 2009 (Yang Tse)
73 - Overhauled ares__get_hostent() Fixing out of bounds memory overwrite
74 triggered with malformed /etc/hosts file. Improving parsing of /etc/hosts
75 file. Validating requested address family. Ensuring that failures always
76 return a NULL pointer. Adjusting header inclusions.
78 * October 6, 2009 (Yang Tse)
79 - Fix ssize_t redefinition errors on WIN64 reported by Alexey Simak.
81 * September 29, 2009 (Yang Tse)
82 - Make configure script also check if _REENTRANT definition is required to
83 make errno available as a preprocessor macro.
85 * September 7, 2009 (Yang Tse)
86 - Add T_SRV portability check to ares_parse_srv_reply.c
88 * 4 Sep 2009 (Daniel Stenberg)
89 - Jakub Hrozek added ares_parse_srv_reply() for SRV parsing
91 * 3 Aug 2009 (Daniel Stenberg)
92 - Joshua Kwan fixed the init routine to fill in the defaults for stuff that
93 fails to get inited by other means. This fixes a case of when the c-ares
94 init fails when internet access is fone.
96 - Timo Teras changed the reason code used in the resolve callback done when
97 ares_cancel() is used, to be ARES_ECANCELLED instead of ARES_ETIMEOUT to
98 better allow the callback to know what's happening.
100 * 14 Jul 2009 (Guenter Knauf)
101 - renamed generated config.h to ares_config.h to avoid any future clashes
102 with config.h from other projects.
104 * June 20 2009 (Yang Tse)
105 - Refactor how libraries are checked for connect() function in configure
106 script and check for connect() as it is done for other functions.
108 * June 19 2009 (Yang Tse)
109 - Make sclose() function-like macro definition used to close a socket,
110 now solely based on HAVE_CLOSESOCKET and HAVE_CLOSESOCKET_CAMEL
111 config file preprocessor definitions
113 * June 18 2009 (Yang Tse)
114 - Add CloseSocket camel case function check for configure script.
116 * June 17 2009 (Yang Tse)
117 - Check for socket() and closesocket() as it is done for other functions
120 * June 11 2009 (Yang Tse)
121 - Modified buildconf so that when automake runs it copies missing files
122 instead of symlinking them.
124 * June 8 2009 (Yang Tse)
125 - Removed buildconf.bat from release and daily snapshot archives. This
126 file is only for CVS tree checkout builds.
128 * May 26 2009 (Yang Tse)
129 - Added --enable-curldebug configure option to enable and disable building
130 with the low-level curl debug memory tracking 'feature' to allow decoupled
131 setting from --enable-debug, allowing again to build c-ares independently
134 For the c-ares library option --enable-debug enables debug build features
135 which are _not_ related with memory tracking. For the c-ares library when
136 --enable-debug is given it does not enable the memory tracking feature. If
137 you wish to enable the curl debug memory tracking you must use configure
138 option --enable-curldebug explicitily to do so.
140 Internally, definition of preprocessor symbol DEBUGBUILD restricts code
141 which is only compiled for debug enabled builds. And symbol CURLDEBUG is
142 used to differentiate code which is _only_ used for memory tracking.
144 Make ares_init(), ares_dup() and ares_init_options() fail returning
145 ARES_ENOTINITIALIZED if library initialization has not been performed
146 calling ares_library_init().
148 * May 20 2009 (Yang Tse)
149 - Added ares_library_init() and ares_library_cleanup() man pages.
151 * May 19 2009 (Yang Tse)
152 - Introduced ares_library_init() and ares_library_cleanup() functions.
154 This is an API and ABI break for Win32/64 systems. Non-Win32/64 build targets
155 using c-ares 1.6.1 can still survive without calling these functions. Read all
156 the details on ares_library_init(3) and ares_library_cleanup(3) man pages that
159 curl/libcurl 7.19.5 is fully compatible with c-ares 1.6.1 on all systems.
161 In order to use c-ares 1.6.1 with curl/libcurl on Win32/64 systems it is
162 required that curl/libcurl is 7.19.5 or newer. In other words, it is not
163 possible on Win32/64 to use c-ares 1.6.1 with a curl/libcurl version less
166 * May 11 2009 (Daniel Stenberg)
167 - Gregor Jasny made c-ares link with libtool 's -export-symbols-regex option to
168 only expose functions starting with ares_.
170 * May 7 2009 (Yang Tse)
171 - Fix an m4 overquoting triggering a spurious 'AS_TR_CPP' symbol definition
172 attempt in generated config.h
174 * May 2 2009 (Yang Tse)
175 - Use a build-time configured ares_socklen_t data type instead of socklen_t.
177 * April 21 2009 (Yang Tse)
178 - Moved potential inclusion of system's malloc.h and memory.h header files to
179 setup_once.h. Inclusion of each header file is based on the definition of
180 NEED_MALLOC_H and NEED_MEMORY_H respectively.
182 * March 11 2009 (Yang Tse)
183 - Japheth Cleaver fixed acountry.c replacing u_long with unsigned long.
185 * February 20 2009 (Yang Tse)
186 - Do not halt compilation when using VS2008 to build a Windows 2000 target.
188 * February 3 2009 (Phil Blundell)
189 - If the server returns garbage or nothing at all in response to an AAAA query,
190 go on and ask for A records anyway.
192 * January 31 2009 (Daniel Stenberg)
193 - ares_gethostbyname() now accepts 'AF_UNSPEC' as a family for resolving
194 either AF_INET6 or AF_INET. It works by accepting any of the looksups in the
195 hosts file, and it resolves the AAAA field with a fallback to A.
197 * January 14 2009 (Daniel Stenberg)
198 - ares.h no longer uses the HAVE_STRUCT_IN6_ADDR define check, but instead it
199 now declares the private struct ares_in6_addr for all systems instead of
200 relying on one possibly not present in the system.
202 * January 13 2009 (Phil Blundell)
203 - ares__send_query() now varies the retry timeout pseudo-randomly to avoid
204 packet storms when several queries were started at the same time.
206 * January 11 2009 (Daniel Stenberg)
207 - Phil Blundell added the internal function ares__expand_name_for_response()
208 that is now used by the ares_parse_*_reply() functions instead of the
209 ares_expand_name() simply to easier return ARES_EBADRESP for the cases where
210 the name expansion fails as in responses that really isn't expected.
212 Version 1.6.0 (Dec 9, 2008)
214 * December 9 2008 (Gisle Vanem)
216 Fixes for Win32 targets using the Watt-32 tcp/ip stack.
218 * Dec 4 2008 (Daniel Stenberg)
220 Gregor Jasny provided the patch that introduces ares_set_socket_callback(),
221 and I edited it to also get duped by ares_dup().
223 * Dec 3 2008 (Daniel Stenberg)
227 I made sure the public ares_config struct looks like before and yet it
228 supports the ROTATE option thanks to c-ares now storing the "optmask"
229 internally. Thus we should be ABI compatible with the past release(s)
230 now. My efforts mentioned below should not break backwards ABI compliance.
232 Here's how I suggest we proceed with the API:
234 ares_init() will be primary "channel creator" function.
236 ares_init_options() will continue to work exactly like now and before. For
237 starters, it will be the (only) way to set the existing options.
239 ares_save_options() will continue to work like today, but will ONLY save
240 options that you can set today (including ARES_OPT_ROTATE actually) but new
241 options that we add may not be saved with this.
243 Instead we introduce:
245 ares_dup() that instead can make a new channel and clone the config used
246 from an existing channel. It will then clone all config options, including
247 future new things we add.
249 ares_set_*() style functions that set (new) config options. As a start we
250 simply add these for new functionality, but over time we can also introduce
251 them for existing "struct ares_options" so that we can eventually deprecate
252 the two ares_*_options() functions.
254 ares_get_*() style functions for extracting info from a channel handle that
255 should be used instead of ares_save_options().
257 * Nov 26 2008 (Yang Tse)
258 - Brad Spencer provided changes to allow buildconf to work on OS X.
260 - Gerald Combs fixed a bug in ares_parse_ptr_reply() which would cause a
261 buffer to shrink instead of expand if a reply contained 8 or more records.
263 * Nov 25 2008 (Yang Tse)
264 - In preparation for the upcomming IPv6 nameservers patch, the internal
265 ares_addr union is now changed into an internal struct which also holds
268 * Nov 19 2008 (Daniel Stenberg)
269 - Brad Spencer brought the new function ares_gethostbyname_file() which simply
270 resolves a host name from the given file, using the regular hosts syntax.
272 * Nov 1 2008 (Daniel Stenberg)
273 - Carlo Contavalli added support for the glibc "rotate" option, as documented
276 causes round robin selection of nameservers from among those listed. This
277 has the effect of spreading the query load among all listed servers, rather
278 than having all clients try the first listed server first every time.
280 You can enable it with ARES_OPT_ROTATE
282 * Oct 21 2008 (Yang Tse)
283 Charles Hardin added handling of EINPROGRESS for UDP connects.
285 * Oct 18 2008 (Daniel Stenberg)
286 Charles Hardin made adig support a regular numerical dotted IP address for the
289 * Oct 7 2008 (Yang Tse)
290 - Added --enable-optimize configure option to enable and disable compiler
291 optimizations to allow decoupled setting from --enable-debug.
293 * Oct 2 2008 (Yang Tse)
294 - Added --enable-warnings configure option to enable and disable strict
295 compiler warnings to allow decoupled setting from --enable-debug.
297 * Sep 17 2008 (Yang Tse)
298 - Code reorganization to allow internal/private use of "nameser.h" to any
299 system that lacks arpa/nameser.h or arpa/nameser_compat.h header files.
301 * Sep 16 2008 (Yang Tse)
302 - Code reorganization to allow internal/private use of ares_writev to any
303 system that lacks the writev function.
305 * Sep 15 2008 (Yang Tse)
306 - Code reorganization to allow internal/private use of ares_strcasecmp to any
307 system that lacks the strcasecmp function.
309 - Improve configure detection of some string functions.
311 * Sep 11 2008 (Yang Tse)
312 - Code reorganization to allow internal/private use of ares_strdup to any
313 system that lacks the strdup function.
315 Version 1.5.3 (Aug 29, 2008)
317 * Aug 25 2008 (Yang Tse)
318 - Improvement by Brad House:
320 This patch addresses an issue in which a response could be sent back to the
321 source port of a client from a different address than the request was made to.
322 This is one form of a DNS cache poisoning attack.
324 The patch simply uses recvfrom() rather than recv() and validates that the
325 address returned from recvfrom() matches the address of the server we have
326 connected to. Only necessary on UDP sockets as they are connection-less, TCP
329 - Fix by George Neill:
330 Fixed compilation of acountry sample application failure on some systems.
332 * Aug 4 2008 (Daniel Stenberg)
333 - Fix by Tofu Linden:
336 * Users (usually, but not always) on 2-Wire routers and the Comcast service
337 and a wired connection to their router would find that the second and
338 subsequent DNS lookups from fresh processes using c-ares to resolve the same
339 address would cause the process to never see a reply (it keeps polling for
340 around 1m15s before giving up).
343 * On such a machine (and yeah, it took us a lot of QA to find the systems
344 that reproduce such a specific problem!), do 'ahost www.secondlife.com',
345 then do it again. The first process's lookup will work, subsequent lookups
346 will time-out and fail.
349 * init_id_key() was calling randomize_key() *before* it initialized
350 key->state, meaning that the randomness generated by randomize_key() is
351 immediately overwritten with deterministic values. (/dev/urandom was also
352 being read incorrectly in the c-ares version we were using, but this was
353 fixed in a later version.)
354 * This makes the stream of generated query-IDs from any new c-ares process
355 be an identical and predictable sequence of IDs.
356 * This makes the 2-Wire's default built-in DNS server detect these queries
357 as probable-duplicates and (erroneously) not respond at all.
360 * Aug 4 2008 (Yang Tse)
361 - Autoconf 2.62 has changed the behaviour of the AC_AIX macro which we use.
362 Prior versions of autoconf defined _ALL_SOURCE if _AIX was defined. 2.62
363 version of AC_AIX defines _ALL_SOURCE and other four preprocessor symbols
364 no matter if the system is AIX or not. To keep the traditional behaviour,
365 and an uniform one across autoconf versions AC_AIX is replaced with our
366 own internal macro CARES_CHECK_AIX_ALL_SOURCE.
368 * Aug 1 2008 (Yang Tse)
369 - Configure process now checks if the preprocessor _REENTRANT symbol is already
370 defined. If it isn't currently defined a set of checks are performed to test
371 if its definition is required to make visible to the compiler a set of *_r
372 functions. Finally, if _REENTRANT is already defined or needed it takes care
373 of making adjustments necessary to ensure that it is defined equally for the
374 configure process tests and generated config file.
376 * Jul 20 2008 (Yang Tse)
377 - When recvfrom prototype uses a void pointer for arguments 2, 5 or 6 this will
378 now cause the definition, as appropriate, of RECVFROM_TYPE_ARG2_IS_VOID,
379 RECVFROM_TYPE_ARG5_IS_VOID or RECVFROM_TYPE_ARG6_IS_VOID.
381 * Jul 17 2008 (Yang Tse)
382 - RECVFROM_TYPE_ARG2, RECVFROM_TYPE_ARG5 and RECVFROM_TYPE_ARG6 are now defined
383 to the data type pointed by its respective argument and not the pointer type.
385 * Jul 16 2008 (Yang Tse)
386 - Improved configure detection of number of arguments for getservbyport_r.
387 Detection is now based on compilation checks instead of linker ones.
389 - Configure process now checks availability of recvfrom() socket function and
390 finds out its return type and the types of its arguments. Added definitions
391 for non-configure systems config files, and introduced macro sreadfrom which
392 will be used on udp sockets as a recvfrom() wrapper in the future.
394 * Jul 15 2008 (Yang Tse)
395 - Introduce definition of _REENTRANT symbol in setup.h to improve library
396 usability. Previously the configure process only used the AC_SYS_LARGEFILE
397 macro for debug builds, now it is also used for non-debug ones enabling the
398 use of configure options --enable-largefile and --disable-largefile which
399 might be needed for library compatibility. Remove checking the size of
400 curl_off_t, it is no longer needed.
402 * Jul 3 2008 (Daniel Stenberg)
403 - Phil Blundell: If you ask ares_gethostbyname() to do an AF_INET6 lookup and
404 the target host has only A records, it automatically falls back to an
405 AF_INET lookup and gives you the A results. However, if the target host has
406 a CNAME record, this behaviour is defeated since the original query does
407 return some data even though ares_parse_aaa_reply() doesn't consider it
408 relevant. Here's a small patch to make it behave the same with and without
411 * Jul 2 2008 (Yang Tse)
412 - Fallback to gettimeofday when monotonic clock is unavailable at run-time.
414 * Jun 30 2008 (Daniel Stenberg)
416 - As was pointed out to me by Andreas Schuldei, the MAXHOSTNAMELEN define is
417 not posix or anything and thus c-ares failed to build on hurd (and possibly
418 elsewhere). The define was also somewhat artificially used in the windows
419 port. Now, I instead rewrote the use of gethostbyname to enlarge the host
420 name buffer in case of need and totally avoid the use of the MAXHOSTNAMELEN
421 define. I thus also removed the defien from the namser.h file where it was
422 once added for the windows build.
424 I also fixed init_by_defaults() function to not leak memory in case if
427 * Jun 9 2008 (Yang Tse)
429 - Make libcares.pc generated file for pkg-config include information relative
430 to the libraries needed for the static linking of c-ares.
432 * May 30 2008 (Yang Tse)
434 - Brad House fixed a missing header file inclusion in adig sample program.
436 Version 1.5.2 (May 29, 2008)
438 * May 13 2008 (Daniel Stenberg)
440 - Introducing millisecond resolution support for the timeout option. See
441 ares_init_options()'s ARES_OPT_TIMEOUTMS.
443 * May 9 2008 (Yang Tse)
445 - Use monotonic time source if available, for private function ares__tvnow()
447 * May 7 2008 (Daniel Stenberg)
449 - Sebastian made c-ares able to return all PTR-records when doing reverse
450 lookups. It is not common practice to have multiple PTR-Records for a single
451 IP, but its perfectly legal and some sites have those.
453 - Doug Goldstein provided a configure patch: updates autoconf 2.13 usage to
454 autoconf 2.57 usage (which is the version you have specified as the minimum
455 version). It's a minor change but it does clean up some warnings with newer
456 autoconf (specifically 2.62).
458 * May 5 2008 (Yang Tse)
460 - Improved parsing of resolver configuration files.
462 * April 4 2008 (Daniel Stenberg)
464 - Eino Tuominen improved the code when a file is used to seed the randomizer.
466 - Alexey Simak made adig support NAPTR records
468 - Alexey Simak fixed the VC dsp file by adding the missing source file
471 * December 11 2007 (Gisle Vanem)
473 - Added another sample application; acountry.c which converts an
474 IPv4-address(es) and/or host-name(s) to country-name and country-code.
475 This uses the service of the DNSBL at countries.nerd.dk.
477 * December 3 2007 (Daniel Stenberg)
479 - Brad Spencer fixed the configure script to assume that there's no
480 /dev/urandom when built cross-compiled as then the script cannot check for
483 - Erik Kline cleaned up ares_gethostbyaddr.c:next_lookup() somewhat
485 Version 1.5.1 (Nov 21, 2007)
487 * November 21 2007 (Daniel Stenberg)
489 - Robin Cornelius pointed out that ares_llist.h was missing in the release
492 Version 1.5.0 (Nov 21, 2007)
494 * October 2 2007 (Daniel Stenberg)
496 - ares_strerror() segfaulted if the input error number was out of the currently
499 - Yang Tse: Avoid a segfault when generating a DNS "Transaction ID" in
500 internal function init_id_key() under low memory conditions.
502 * September 28 2007 (Daniel Stenberg)
504 - Bumped version to 1.5.0 for next release and soname bumped to 2 due to ABI
505 and API changes in the progress callback (and possibly more coming up from
508 * September 28 2007 (Steinar H. Gunderson)
510 - Don't skip a server if it's the only one. (Bugfix from the Google tree.)
512 - Made the query callbacks receive the number of timeouts that happened during
513 the execution of a query, and updated documentation accordingly. (Patch from
516 - Support a few more socket options: ARES_OPT_SOCK_SNDBUF and
519 - Always register for TCP events even if there are no outstanding queries, as
520 the other side could always close the connection, which is a valid event
521 which should be responded to.
523 * September 22 2007 (Daniel Stenberg)
525 - Steinar H. Gunderson fixed: Correctly clear sockets from the fd_set on in
526 several functions (write_tcp_data, read_tcp_data, read_udp_packets) so that
527 if it fails and the socket is closed the following code doesn't try to use
530 - Steinar H. Gunderson modified c-ares to now also do to DNS retries even when
531 TCP is used since there are several edge cases where it still makes sense.
533 - Brad House provided a fix for ares_save_options():
535 Apparently I overlooked something with the ares_save_options() where it
536 would try to do a malloc(0) when no options of that type needed to be saved.
537 On most platforms, this was fine because malloc(0) doesn't actually return
538 NULL, but on AIX it does, so ares_save_options would return ARES_ENOMEM.
540 * July 14 2007 (Daniel Stenberg)
542 - Vlad Dinulescu fixed two outstanding valgrind reports:
544 1. In ares_query.c , in find_query_by_id we compare q->qid (which is a short
545 int variable) with qid, which is declared as an int variable. Moreover,
546 DNS_HEADER_SET_QID is used to set the value of qid, but DNS_HEADER_SET_QID
547 sets only the first two bytes of qid. I think that qid should be declared as
548 "unsigned short" in this function.
550 2. The same problem occurs in ares_process.c, process_answer() . query->qid
551 (an unsigned short integer variable) is compared with id, which is an
552 integer variable. Moreover, id is initialized from DNS_HEADER_QID which sets
553 only the first two bytes of id. I think that the id variable should be
554 declared as "unsigned short" in this function.
556 Even after declaring these variables as "unsigned short", the valgrind
557 errors are still there. Which brings us to the third problem.
559 3. The third problem is that Valgrind assumes that query->qid is not
560 initialised correctly. And it does that because query->qid is set from
561 DNS_HEADER_QID(qbuf); Valgrind says that qbuf has unitialised bytes. And
562 qbuf has uninitialised bytes because of channel->next_id . And next_id is
563 set by ares_init.c:ares__generate_new_id() . I found that putting short r=0
564 in this function (instead of short r) makes all Valgrind warnings go away.
565 I have studied ares__rc4() too, and this is the offending line:
567 buffer_ptr[counter] ^= state[xorIndex]; (ares_query.c:62)
569 This is what triggers Valgrind.. buffer_ptr is unitialised in this function,
570 and by applying ^= on it, it remains unitialised.
572 Version 1.4.0 (June 8, 2007)
574 * June 4 2007 (Daniel Stenberg)
576 - James Bursa reported a major memory problem when resolving multi-IP names
577 and I found and fixed the problem. It was added by Ashish Sharma's patch
580 When I then tried to verify multiple entries in /etc/hosts after my fix, I
581 got another segfault and decided this code was not ripe for inclusion and I
586 - Brad Spencer found and fixed three flaws in the code, found with the new
587 gcc 4.2.0 warning: -Waddress
589 - Brad House fixed VS2005 compiler warnings due to time_t being 64bit.
590 He also made recent Microsoft compilers use _strdup() instead of strdup().
592 - Brad House's man pages for ares_save_options() and ares_destroy_options()
595 - Ashish Sharma provided a patch for supporting multiple entries in the
596 /etc/hosts file. Patch edited for coding style and functionality by me
601 - Shmulik Regev brought cryptographically secure transaction IDs:
603 The c-ares library implementation uses a DNS "Transaction ID" field that is
604 seeded with a pseudo random number (based on gettimeofday) which is
605 incremented (++) between consecutive calls and is therefore rather
606 predictable. In general, predictability of DNS Transaction ID is a well
607 known security problem (e.g.
608 http://bak.spc.org/dms/archive/dns_id_attack.txt) and makes a c-ares based
609 implementation vulnerable to DNS poisoning. Credit goes to Amit Klein
610 (Trusteer) for identifying this problem.
612 The patch I wrote changes the implementation to use a more secure way of
613 generating unique IDs. It starts by obtaining a key with reasonable entropy
614 which is used with an RC4 stream to generate the cryptographically secure
617 Note that the key generation code (in ares_init:randomize_key) has two
618 versions, the Windows specific one uses a cryptographically safe function
619 provided (but undocumented :) by the operating system (described at
620 http://blogs.msdn.com/michael_howard/archive/2005/01/14/353379.aspx). The
621 default implementation is a bit naive and uses the standard 'rand'
622 function. Surely a better way to generate random keys exists for other
625 The patch can be tested by using the adig utility and using the '-s' option.
627 - Brad House added ares_save_options() and ares_destroy_options() that can be
628 used to keep options for later re-usal when ares_init_options() is used.
630 Problem: Calling ares_init() for each lookup can be unnecessarily resource
631 intensive. On windows, it must LoadLibrary() or search the registry
632 on each call to ares_init(). On unix, it must read and parse
633 multiple files to obtain the necessary configuration information. In
634 a single-threaded environment, it would make sense to only
635 ares_init() once, but in a heavily multi-threaded environment, it is
636 undesirable to ares_init() and ares_destroy() for each thread created
639 Solution: Create ares_save_options() and ares_destroy_options() functions to
640 retrieve and free options obtained from an initialized channel. The
641 options populated can be used to pass back into ares_init_options(),
642 it should populate all needed fields and not retrieve any information
643 from the system. Probably wise to destroy the cache every minute or
644 so to prevent the data from becoming stale.
646 - Daniel S added ares_process_fd() to allow applications to ask for processing
647 on specific sockets and thus avoiding select() and associated
648 functions/macros. This function will be used by upcoming libcurl releases
649 for this very reason. It also made me export the ares_socket_t type in the
650 public ares.h header file, since ares_process_fd() uses that type for two of
655 - Ravi Pratap fixed a flaw in the init_by_resolv_conf() function for windows
656 that could cause it to return a bad return code.
660 - Yang Tse: Provide ares_getopt() command-line parser function as a source
661 code helper function, not belonging to the actual c-ares library.
665 - Vlad Dinulescu added ares_parse_ns_reply().
669 - Yang Tse: Fix failure to get the search sequence of /etc/hosts and
670 DNS from /etc/nsswitch.conf, /etc/host.conf or /etc/svc.conf when
671 /etc/resolv.conf did not exist or was unable to read it.
675 - Install ares_dns.h too
677 - Michael Wallner fixed this problem: When I set domains in the options
678 struct, and there are domain/search entries in /etc/resolv.conf, the domains
679 of the options struct will be overridden.
683 - Yang Tse removed a couple of potential zero size memory allocations.
685 - Andreas Rieke fixed the line endings in the areslib.dsp file that I (Daniel)
686 broke in the 1.3.2 release. We should switch to a system where that file is
687 auto-generated. We could rip some code for that from curl...
689 Version 1.3.2 (November 3, 2006)
693 - Prevent ares_getsock() to overflow if more than 16 sockets are used.
697 - Guilherme Balena Versiani: I noted a strange BUG in Win32 port
698 (ares_init.c/get_iphlpapi_dns_info() function): when I disable the network
699 by hand or disconnect the network cable in Windows 2000 or Windows XP, my
700 application gets 127.0.0.1 as the only name server. The problem comes from
701 'GetNetworkParams' function, that returns the empty string "" as the only
702 name server in that case. Moreover, the Windows implementation of
703 inet_addr() returns INADDR_LOOPBACK instead of INADDR_NONE.
709 o made ares_version.h use extern "C" for c++ compilers
710 o fixed compiler warnings in ares_getnameinfo.c
711 o fixed a buffer position init for TCP reads
715 - Ravi Pratap fixed ares_getsock() to actually return the proper bitmap and
718 Version 1.3.1 (June 24, 2006)
722 - Gisle Vanem added getopt() to the ahost program. Currently accepts
723 only [-t {a|aaaa}] to specify address family in ares_gethostbyname().
727 - (wahern) Removed "big endian" DNS section and RR data integer parser
728 macros from ares_dns.h, which break c-ares on my Sparc64. Bit-wise
729 operations in C operate on logical values. And in any event the octets are
730 already in big-endian (aka network) byte order so they're being reversed
731 (thus the source of the breakage).
735 - William Ahern handles EAGAIN/EWOULDBLOCK errors in most of the I/O calls
738 TODO: Handle one last EAGAIN for a UDP socket send(2) in
743 - Bram Matthys brought my attention to a libtool peculiarity where detecting
744 things such as C++ compiler actually is a bad thing and since we don't need
745 that detection I added a work-around, much inspired by a previous patch by
746 Paolo Bonzini. This also shortens the configure script quite a lot.
750 - Nick Mathewson added the ARES_OPT_SOCK_STATE_CB option that when set makes
751 c-ares call a callback on socket state changes. A better way than the
752 ares_getsock() to get full control over the socket state.
756 - Alexander Lazic improved the getservbyport_r() configure check.
760 - Alexander Lazic pointed out that the buildconf should use the ACLOCAL_FLAGS
761 variable for easier controlling what it does and how it runs.
765 - James Bursa fixed c-ares to find the hosts file on RISC OS, and made it
766 build with newer gcc versions that no longer defines "riscos".
770 - Daniel Stenberg added ares_getsock() that extracts the set of sockets to
771 wait for action on. Similar to ares_fds() but not restricted to using
772 select() for the waiting.
776 - Yang Tse fixed some send() / recv() compiler warnings
780 - Added constants that will be used by ares_getaddrinfo
782 - Made ares_getnameinfo use the reentrant getservbyport (getservbyport_r) if it
783 is available to ensure it works properly in a threaded environment.
787 - configure fix for detecting a member in the sockaddr_in6 struct which failed
788 on ipv6-enabled HP-UX 11.00
790 Version 1.3.0 (August 29, 2005)
794 - Alfredo Tupone provided a fix for the Windows code in get_iphlpapi_dns_info()
795 when getting the DNS server etc.
799 - Added some checks for the addrinfo structure.
805 Make UDP sockets non-blocking. I've confirmed that at least on Linux 2.4 a
806 read event can come back from poll() on a valid SOCK_DGRAM socket but
807 recv(2) will still block. This patch doesn't ignore EAGAIN in
808 read_udp_packets(), though maybe it should. (This patch was edited by Daniel
809 Stenberg and a new configure test was added (imported from curl's configure)
810 to properly detect what non-blocking socket approach to use.)
812 I'm not quite sure how this was happening, but I've been seeing PTR queries
813 which seem to return empty responses. At least, they were empty when calling
814 ares_expand_name() on the record. Here's a patch which guarantees to
815 NUL-terminate the expanded name. The old behavior failed to NUL-terminate if
816 len was 0, and this was causing strlen() to run past the end of the buffer
817 after calling ares_expand_name() and getting ARES_SUCCESS as the return
818 value. If q is not greater than *s then it's equal and *s is always
819 allocated with at least one byte.
823 - Added ares_getnameinfo which mimics the getnameinfo API (another feature
824 that could use testing).
828 - Added an inet_ntop function from BIND for systems that do not have it.
832 - Made sortlist support IPv6 (this can probably use some testing).
834 - Made sortlist support CIDR matching for IPv4.
838 - Added preliminary IPv6 support to ares_gethostbyname. Currently, sortlist
839 does not work with IPv6. Also provided an implementation of bitncmp from
840 BIND for systems that do not supply this function. This will be used to add
841 IPv6 support to sortlist.
843 - Made ares_gethostbyaddr support IPv6 by specifying AF_INET6 as the family.
844 The function can lookup IPv6 addresses both from files (/etc/hosts) and
849 - Tupone Alfredo fixed includes of arpa/nameser_compat.h to build fine on Mac
854 - Dominick Meglio: Provided implementations of inet_net_pton and inet_pton
855 from BIND for systems that do not include these functions.
859 - Dominick Meglio added ares_parse_aaaa_reply.c and did various
860 adjustments. The first little steps towards IPv6 support!
864 - Fixed the VC project and makefile to use ares_cancel and ares_version
868 - The released ares_version.h from 1.2.1 says 1.2.0 due to a maketgz flaw.
871 Version 1.2.1 (October 20, 2004)
875 - Henrik Stoerner fix: got a report that Tru64 Unix (the unix from Digital
876 when they made Alpha's) uses /etc/svc.conf for the purpose fixed below for
877 other OSes. He made c-ares check for and understand it if present.
879 - Now c-ares will use local host name lookup _before_ DNS resolving by default
880 if nothing else is told.
884 - Henrik Stoerner: found out that c-ares does not look at the /etc/host.conf
885 file to determine the sequence in which to search /etc/hosts and DNS. So on
886 systems where this order is defined by /etc/host.conf instead of a "lookup"
887 entry in /etc/resolv.conf, c-ares will always default to looking in DNS
888 first, and /etc/hosts second.
892 1) resolv.conf (for the "lookup" line);
893 2) nsswitch.fon (for the "hosts:" line);
894 3) host.conf (for the "order" line).
898 - Dominick Meglio patched: C-ares on Windows assumed that the HOSTS file is
899 located in a static location. It assumed
900 C:\Windows\System32\Drivers\Etc. This is a poor assumption to make. In fact,
901 the location of the HOSTS file can be changed via a registry setting.
903 There is a key called DatabasePath which specifies the path to the HOSTS
905 http://www.microsoft.com/technet/itsolutions/network/deploy/depovg/tcpip2k.mspx
907 The patch will make c-ares correctly consult the registry for the location
912 - Gisle Vanem fixed the MSVC build files.
916 - Gisle Vanem made c-ares build and work with his Watt-32 TCP/IP stack.
920 - Harshal Pradhan made a minor syntax change in ares_init.c to make it build
925 - Made the lib get built static only if --enable-debug is used.
929 Basically in loops like handle_errors(), 'query->next' was assigned a local
930 variable and then query was referenced after the memory was freed by
931 next_server(). I've changed that so next_server() and end_query() returns
932 the next query. So callers should use this ret-value.
934 The next problem was that 'server->tcp_buffer_pos' had a random value at
935 entry to 1st recv() (luckily causing Winsock to return ENOBUFS).
937 I've also added a ares_writev() for Windows to streamline the code a bit
941 - Fixed a few variable return types for some system calls. Made configure
942 check for ssize_t to make it possible to use that when receiving the send()
943 error code. This is necessary to prevent compiler warnings on some systems.
945 - Made configure create config.h, and all source files now include setup.h that
946 might include the proper config.h (or a handicrafted alternative).
948 - Switched to 'ares_socket_t' type for sockets in ares, since Windows don't
951 - automake-ified and libool-ified c-ares. Now it builds libcares as a shared
952 lib on most platforms if wanted. (This bloated the size of the release
953 archive with another 200K!)
955 - Makefile.am now uses Makefile.inc for the c sources, h headers and man
956 pages, to make it easier for other makefiles to use the exact same set of
959 - Adjusted 'maketgz' to use the new automake magic when building distribution
962 - Anyone desires HTML and/or PDF versions of the man pages in the release
966 - Günter Knauf made c-ares build and run on Novell Netware.
969 - Gisle Vanem provided Makefile.dj to build with djgpp, added a few more djgpp
970 fixes and made ares not use 'errno' to provide further info on Windows.
973 - Gisle Vanem made it build with djgpp and run fine with the Watt-32 stack.
976 - Gisle Vanem's init patch for Windows:
978 The init_by_resolv_conf() function fetches the DNS-server(s)
979 from a series of registry branches.
981 This can be wrong in the case where DHCP has assigned nameservers, but the
982 user has overridden these servers with other prefered settings. Then it's
983 wrong to use the DHCPNAMESERVER setting in registry.
985 In the case of no global DHCP-assigned or fixed servers, but DNS server(s)
986 per adapter, one has to query the adapter branches. But how can c-ares know
987 which adapter is valid for use? AFAICS it can't. There could be one adapter
988 that is down (e.g. a VPN adapter).
990 So it's better to leave this to the IP Helper API (iphlapi) available in
991 Win-98/2000 and later. My patch falls-back to the old way if not available.
994 - James Bursa fixed an init issue for RISC OS.
997 - Nico Stappenbelt reported that when processing domain and search lines in
998 the resolv.conf file, the first entry encountered is processed and used as
999 the search list. According to the manual pages for both Linux, Solaris and
1000 Tru64, the last entry of either a domain or a search field is used.
1002 This is now adjusted in the code
1004 Version 1.2.0 (April 13, 2004)
1007 - Updated various man pages to look nicer when converted to HTML on the web
1011 - Dirk Manske provided a new function that is now named ares_cancel(). It is
1012 used to cancel/cleanup a resolve/request made using ares functions on the
1013 given ares channel. It does not destroy/kill the ares channel itself.
1015 - Dominick Meglio cleaned up the formatting in several man pages.
1018 - Dominick Meglio's new ares_expand_string. A helper function when decoding
1019 incoming DNS packages.
1021 - Daniel Stenberg modified the Makefile.in to use a for loop for the man page
1022 installation to improve overview and make it easier to add man pages.
1024 Version 1.1.0 (March 11, 2004)
1027 - Gisle Vanem improved build on Windows.
1030 - Dan Fandrich found a flaw in the Feb 22 fix.
1032 - Added better configure --enable-debug logic (taken from the curl configure
1033 script). Added acinclude.m4 to the tarball.
1036 - Removed ares_free_errmem(), the function, the file and the man page. It was
1037 not used and it did nothing.
1039 - Fixed a lot of code that wasn't "64bit clean" and thus caused a lot of
1040 compiler warnings on picky compilers.
1043 - Dominick Meglio made ares init support multiple name servers in the
1044 NameServer key on Windows.
1047 - Modified ares_private.h to include libcurl's memory debug header if
1048 CURLDEBUG is set. This makes all the ares-functions supervised properly by
1049 the curl test suite. This also forced me to add inclusion of the
1050 ares_private.h header in a few more files that are using some kind of
1051 memory-related resources.
1053 - Made the makefile only build ahost and adig if 'make demos' is used.
1056 - Dirk Manske made ares_version.h installed with 'make install'
1059 - ares_free_errmem() is subject for removal, it is simply present for future
1060 purposes, and since we removed the extra parameter in strerror() it won't
1062 - configure --enable-debug now enables picky compiler options if gcc is used
1063 - fixed several compiler warnings --enable-debug showed and Joerg Mueller-Tolk
1066 Version 1.0.0 (February 3, 2004)
1069 - now we produce the libcares.a library instead of the previous libares.a
1070 since we are no longer compatible
1074 - ares_strerror() has one argument less. This is the first official
1075 modification of the existing provided ares API.
1079 - Dirk Manske fixed how the socket is set non-blocking.
1083 - Dominick Meglio made the private gettimeofday() become ares_gettimeofday()
1084 instead in order to not pollute the name space and risk colliding with
1085 other libraries' versions of this function.
1087 * October 24, 2003. Daniel Stenberg
1089 Added ares_version().
1091 Version 1.0-pre1 (8 October 2003)
1093 - James Bursa made it run on RISC OS
1095 - Dominick Meglio made it run fine on NT4
1097 - Duncan Wilcox made it work fine on Mac OS X
1099 - Daniel Stenberg adjusted the windows port
1101 - liren at vivisimo.com made the initial windows port
1103 * Imported the sources from ares 1.1.1