28  * Only for ares-enabled builds
67 #include <ares.h>
68 #include <ares_version.h> /* really old c-ares did not include this by
72 /* c-ares 1.5.0 or later, the callback proto is modified */
102   int num_pending; /* number of outstanding c-ares requests */
103   struct Curl_addrinfo *temp_ai; /* intermediary result while fetching c-ares
113    obtaining a "definitive" one. For old c-ares without getaddrinfo.
115    This is intended to equal the c-ares default timeout. cURL always uses that
116    default value. Unfortunately, c-ares does not expose its default timeout in
130  * environment. Initializes ares library.
147  * Deinitializes ares library.
183      if c ares < 1.20.0: curl set timeout to CARES_TIMEOUT_PER_ATTEMPT (2s)  in Curl_resolver_init()
185      if c-ares >= 1.20.0 it already has the timeout to 2s, curl does not need  in Curl_resolver_init()
188      if c-ares >= 1.24.0, user can set the timeout via /etc/resolv.conf to  in Curl_resolver_init()
189      overwrite c-ares' timeout.  in Curl_resolver_init()
206      ares channel before returning error! */  in Curl_resolver_init()
214  * structure). Destroys the ares channel.
226  * 'from' ares channel and passes the resulting channel to the 'to' pointer.
253  * We are equivalent to Curl_resolver_cancel() for the c-ares resolver. We
284  * with ares. The caller must make sure that this function is only called when
285  * we have a working ares channel.
307  * 1) Ask ares what sockets it currently plays with, then
308  * 2) wait for the timeout period to check for action on ares' sockets.
309  * 3) tell ares to act on all the sockets marked as "with action"
353        above, as otherwise the ares name resolve will not timeout! */  in waitperform()
403     /* Cancel the raw c-ares request, which will fire query_completed_cb() with  in Curl_resolver_is_resolved()
476     /* use the timeout period ares returned to us above if less than one  in Curl_resolver_wait_resolv()
508     /* failure, so we cancel the ares operation */  in Curl_resolver_wait_resolv()
519     connclose(data->conn, "c-ares resolve failed");  in Curl_resolver_wait_resolv()
558  * ares_query_completed_cb() is the callback that ares will call when
560  * when using ares, is completed either successfully or with failure.
577     /* when this ares handle is getting destroyed, the 'arg' pointer may not  in query_completed_cb()
601        /* Only these c-ares status values count as "definitive" for these  in query_completed_cb()
632          the first place. Without modifying c-ares, we cannot know exactly  in query_completed_cb()
639          c-ares query timeout. That is enough time for a typical parallel  in query_completed_cb()
643          c-ares timeout (5 seconds) plus the round trip time for the successful  in query_completed_cb()
644          request, which seems bearable. The downside is that c-ares might race  in query_completed_cb()
648          c-ares retry cycle each request is.  in query_completed_cb()
657 /* c-ares 1.16.0 or later */
660  * ares2addr() converts an address list provided by c-ares to an internal
749  * Curl_resolver_getaddrinfo() - when using ares
798        * accordingly to save a call to getservbyname in inside C-Ares  in Curl_resolver_getaddrinfo()
842    * from ares library, which will cause any and all queries to fail.  in Curl_set_dns_servers()
844    * any changes to c-ares. This lets c-ares use its defaults, which  in Curl_set_dns_servers()
872 #else /* too old c-ares version! */  in Curl_set_dns_servers()
889 #else /* c-ares version too old! */  in Curl_set_dns_interface()
916 #else /* c-ares version too old! */  in Curl_set_dns_local_ip4()
943 #else /* c-ares version too old! */  in Curl_set_dns_local_ip6()