lib/hostares.c - third_party/curl - Git at Google

 /***************************************************************************
  *                                  _   _ ____  _
  *  Project                     ___| | | |  _ \| |
  *                             / __| | | | |_) | |
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
  * Copyright (C) 1998 - 2011, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
  * are also available at http://curl.haxx.se/docs/copyright.html.
  *
  * You may opt to use, copy, modify, merge, publish, distribute and/or sell
  * copies of the Software, and permit persons to whom the Software is
  * furnished to do so, under the terms of the COPYING file.
  *
  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  * KIND, either express or implied.
  *
  ***************************************************************************/

 #include "setup.h"

 #include <string.h>

 #ifdef HAVE_LIMITS_H
 #include <limits.h>
 #endif
 #ifdef HAVE_SYS_SOCKET_H
 #include <sys/socket.h>
 #endif
 #ifdef HAVE_NETINET_IN_H
 #include <netinet/in.h>
 #endif
 #ifdef HAVE_NETDB_H
 #include <netdb.h>
 #endif
 #ifdef HAVE_ARPA_INET_H
 #include <arpa/inet.h>
 #endif
 #ifdef HAVE_STDLIB_H
 #include <stdlib.h>     /* required for free() prototypes */
 #endif
 #ifdef HAVE_UNISTD_H
 #include <unistd.h>     /* for the close() proto */
 #endif
 #ifdef __VMS
 #include <in.h>
 #include <inet.h>
 #include <stdlib.h>
 #endif

 #ifdef HAVE_PROCESS_H
 #include <process.h>
 #endif

 #if (defined(NETWARE) && defined(__NOVELL_LIBC__))
 #undef in_addr_t
 #define in_addr_t unsigned long
 #endif

 #include "urldata.h"
 #include "sendf.h"
 #include "hostip.h"
 #include "hash.h"
 #include "share.h"
 #include "strerror.h"
 #include "url.h"
 #include "multiif.h"
 #include "inet_pton.h"
 #include "connect.h"
 #include "select.h"
 #include "progress.h"

 #define _MPRINTF_REPLACE /* use our functions only */
 #include <curl/mprintf.h>

 #include "curl_memory.h"
 /* The last #include file should be: */
 #include "memdebug.h"

 /***********************************************************************
  * Only for ares-enabled builds
  **********************************************************************/

 #ifdef CURLRES_ARES

 /*
  * Curl_resolv_fdset() is called when someone from the outside world (using
  * curl_multi_fdset()) wants to get our fd_set setup and we're talking with
  * ares. The caller must make sure that this function is only called when we
  * have a working ares channel.
  *
  * Returns: CURLE_OK always!
  */

 int Curl_resolv_getsock(struct connectdata *conn,
                         curl_socket_t *socks,
                         int numsocks)

 {
   struct timeval maxtime;
   struct timeval timebuf;
   struct timeval *timeout;
   int max = ares_getsock(conn->data->state.areschannel,
                          (ares_socket_t *)socks, numsocks);


   maxtime.tv_sec = CURL_TIMEOUT_RESOLVE;
   maxtime.tv_usec = 0;

   timeout = ares_timeout(conn->data->state.areschannel, &maxtime, &timebuf);

   Curl_expire(conn->data,
               (timeout->tv_sec * 1000) + (timeout->tv_usec/1000));

   return max;
 }

 /*
  * waitperform()
  *
  * 1) Ask ares what sockets it currently plays with, then
  * 2) wait for the timeout period to check for action on ares' sockets.
  * 3) tell ares to act on all the sockets marked as "with action"
  *
  * return number of sockets it worked on
  */

 static int waitperform(struct connectdata *conn, int timeout_ms)
 {
   struct SessionHandle *data = conn->data;
   int nfds;
   int bitmask;
   ares_socket_t socks[ARES_GETSOCK_MAXNUM];
   struct pollfd pfd[ARES_GETSOCK_MAXNUM];
   int i;
   int num = 0;

   bitmask = ares_getsock(data->state.areschannel, socks, ARES_GETSOCK_MAXNUM);

   for(i=0; i < ARES_GETSOCK_MAXNUM; i++) {
     pfd[i].events = 0;
     pfd[i].revents = 0;
     if(ARES_GETSOCK_READABLE(bitmask, i)) {
       pfd[i].fd = socks[i];
       pfd[i].events |= POLLRDNORM|POLLIN;
     }
     if(ARES_GETSOCK_WRITABLE(bitmask, i)) {
       pfd[i].fd = socks[i];
       pfd[i].events |= POLLWRNORM|POLLOUT;
     }
     if(pfd[i].events != 0)
       num++;
     else
       break;
   }

   if(num)
     nfds = Curl_poll(pfd, num, timeout_ms);
   else
     nfds = 0;

   if(!nfds)
     /* Call ares_process() unconditonally here, even if we simply timed out
        above, as otherwise the ares name resolve won't timeout! */
     ares_process_fd(data->state.areschannel, ARES_SOCKET_BAD, ARES_SOCKET_BAD);
   else {
     /* move through the descriptors and ask for processing on them */
     for(i=0; i < num; i++)
       ares_process_fd(data->state.areschannel,
                       pfd[i].revents & (POLLRDNORM|POLLIN)?
                       pfd[i].fd:ARES_SOCKET_BAD,
                       pfd[i].revents & (POLLWRNORM|POLLOUT)?
                       pfd[i].fd:ARES_SOCKET_BAD);
   }
   return nfds;
 }

 /*
  * Curl_is_resolved() is called repeatedly to check if a previous name resolve
  * request has completed. It should also make sure to time-out if the
  * operation seems to take too long.
  *
  * Returns normal CURLcode errors.
  */
 CURLcode Curl_is_resolved(struct connectdata *conn,
                           struct Curl_dns_entry **dns)
 {
   struct SessionHandle *data = conn->data;

   *dns = NULL;

   waitperform(conn, 0);

   if(conn->async.done) {
     /* we're done, kill the ares handle */
     if(!conn->async.dns) {
       failf(data, "Could not resolve host: %s (%s)", conn->host.dispname,
             ares_strerror(conn->async.status));
       return CURLE_COULDNT_RESOLVE_HOST;
     }
     *dns = conn->async.dns;
   }

   return CURLE_OK;
 }

 /*
  * Curl_wait_for_resolv() waits for a resolve to finish. This function should
  * be avoided since using this risk getting the multi interface to "hang".
  *
  * If 'entry' is non-NULL, make it point to the resolved dns entry
  *
  * Returns CURLE_COULDNT_RESOLVE_HOST if the host was not resolved, and
  * CURLE_OPERATION_TIMEDOUT if a time-out occurred.
  */
 CURLcode Curl_wait_for_resolv(struct connectdata *conn,
                               struct Curl_dns_entry **entry)
 {
   CURLcode rc=CURLE_OK;
   struct SessionHandle *data = conn->data;
   long timeout;
   struct timeval now = Curl_tvnow();

   timeout = Curl_timeleft(data, &now, TRUE);
   if(!timeout)
     timeout = CURL_TIMEOUT_RESOLVE * 1000; /* default name resolve timeout */

   /* Wait for the name resolve query to complete. */
   for(;;) {
     struct timeval *tvp, tv, store;
     long timediff;
     int itimeout;
     int timeout_ms;

     itimeout = (timeout > (long)INT_MAX) ? INT_MAX : (int)timeout;

     store.tv_sec = itimeout/1000;
     store.tv_usec = (itimeout%1000)*1000;

     tvp = ares_timeout(data->state.areschannel, &store, &tv);

     /* use the timeout period ares returned to us above if less than one
        second is left, otherwise just use 1000ms to make sure the progress
        callback gets called frequent enough */
     if(!tvp->tv_sec)
       timeout_ms = (int)(tvp->tv_usec/1000);
     else
       timeout_ms = 1000;

     waitperform(conn, timeout_ms);

     if(conn->async.done)
       break;

     if(Curl_pgrsUpdate(conn)) {
       rc = CURLE_ABORTED_BY_CALLBACK;
       timeout = -1; /* trigger the cancel below */
     }
     else {
       struct timeval now2 = Curl_tvnow();
       timediff = Curl_tvdiff(now2, now); /* spent time */
       timeout -= timediff?timediff:1; /* always deduct at least 1 */
       now = now2; /* for next loop */
     }
     if(timeout < 0) {
       /* our timeout, so we cancel the ares operation */
       ares_cancel(data->state.areschannel);
       break;
     }
   }

   /* Operation complete, if the lookup was successful we now have the entry
      in the cache. */

   if(entry)
     *entry = conn->async.dns;

   if(!conn->async.dns) {
     /* a name was not resolved */
     if((timeout < 0) || (conn->async.status == ARES_ETIMEOUT)) {
       if (conn->bits.httpproxy) {
         failf(data, "Resolving proxy timed out: %s", conn->proxy.dispname);
         rc = CURLE_COULDNT_RESOLVE_PROXY;
       }
       else {
         failf(data, "Resolving host timed out: %s", conn->host.dispname);
         rc = CURLE_COULDNT_RESOLVE_HOST;
       }
     }
     else if(conn->async.done) {
       if (conn->bits.httpproxy) {
         failf(data, "Could not resolve proxy: %s (%s)", conn->proxy.dispname,
               ares_strerror(conn->async.status));
         rc = CURLE_COULDNT_RESOLVE_PROXY;
       }
       else {
         failf(data, "Could not resolve host: %s (%s)", conn->host.dispname,
               ares_strerror(conn->async.status));
         rc = CURLE_COULDNT_RESOLVE_HOST;
       }
     }
     else
       rc = CURLE_OPERATION_TIMEDOUT;

     /* close the connection, since we can't return failure here without
        cleaning up this connection properly */
     conn->bits.close = TRUE;
   }

   return rc;
 }

 /*
  * ares_query_completed_cb() is the callback that ares will call when
  * the host query initiated by ares_gethostbyname() from Curl_getaddrinfo(),
  * when using ares, is completed either successfully or with failure.
  */
 static void ares_query_completed_cb(void *arg,  /* (struct connectdata *) */
                                     int status,
 #ifdef HAVE_CARES_CALLBACK_TIMEOUTS
                                     int timeouts,
 #endif
                                     struct hostent *hostent)
 {
   struct connectdata *conn = (struct connectdata *)arg;
   struct Curl_addrinfo * ai = NULL;

 #ifdef HAVE_CARES_CALLBACK_TIMEOUTS
   (void)timeouts; /* ignored */
 #endif

   switch(status) {
   case CURL_ASYNC_SUCCESS:
     ai = Curl_he2ai(hostent, conn->async.port);
     break;
   case ARES_EDESTRUCTION:
     /* this ares handle is getting destroyed, the 'arg' pointer may not be
        valid! */
     return;
   default:
     /* do nothing */
     break;
   }

   (void)Curl_addrinfo_callback(arg, status, ai);
 }

 /*
  * Curl_getaddrinfo() - when using ares
  *
  * Returns name information about the given hostname and port number. If
  * successful, the 'hostent' is returned and the forth argument will point to
  * memory we need to free after use. That memory *MUST* be freed with
  * Curl_freeaddrinfo(), nothing else.
  */
 Curl_addrinfo *Curl_getaddrinfo(struct connectdata *conn,
                                 const char *hostname,
                                 int port,
                                 int *waitp)
 {
   char *bufp;
   struct SessionHandle *data = conn->data;
   struct in_addr in;
   int family = PF_INET;
 #ifdef ENABLE_IPV6 /* CURLRES_IPV6 */
   struct in6_addr in6;
 #endif /* CURLRES_IPV6 */

   *waitp = 0; /* default to synchronous response */

   /* First check if this is an IPv4 address string */
   if(Curl_inet_pton(AF_INET, hostname, &in) > 0) {
     /* This is a dotted IP address 123.123.123.123-style */
     return Curl_ip2addr(AF_INET, &in, hostname, port);
   }

 #ifdef ENABLE_IPV6 /* CURLRES_IPV6 */
   /* Otherwise, check if this is an IPv6 address string */
   if (Curl_inet_pton (AF_INET6, hostname, &in6) > 0) {
     /* This must be an IPv6 address literal.  */
     return Curl_ip2addr(AF_INET6, &in6, hostname, port);
   }

   switch(conn->ip_version) {
   default:
 #if ARES_VERSION >= 0x010601
     family = PF_UNSPEC; /* supported by c-ares since 1.6.1, so for older
                            c-ares versions this just falls through and defaults
                            to PF_INET */
     break;
 #endif
   case CURL_IPRESOLVE_V4:
     family = PF_INET;
     break;
   case CURL_IPRESOLVE_V6:
     family = PF_INET6;
     break;
   }
 #endif /* CURLRES_IPV6 */

   bufp = strdup(hostname);

   if(bufp) {
     Curl_safefree(conn->async.hostname);
     conn->async.hostname = bufp;
     conn->async.port = port;
     conn->async.done = FALSE;   /* not done */
     conn->async.status = 0;     /* clear */
     conn->async.dns = NULL;     /* clear */
     conn->async.temp_ai = NULL; /* clear */

 #ifdef ENABLE_IPV6 /* CURLRES_IPV6 */
     if(family == PF_UNSPEC) {
       conn->async.num_pending = 2;

       /* areschannel is already setup in the Curl_open() function */
       ares_gethostbyname(data->state.areschannel, hostname, PF_INET,
                          ares_query_completed_cb, conn);
       ares_gethostbyname(data->state.areschannel, hostname, PF_INET6,
                          ares_query_completed_cb, conn);
     }
     else
 #endif /* CURLRES_IPV6 */
     {
       conn->async.num_pending = 1;

       /* areschannel is already setup in the Curl_open() function */
       ares_gethostbyname(data->state.areschannel, hostname, family,
                          ares_query_completed_cb, conn);
     }

     *waitp = 1; /* expect asynchronous response */
   }
   return NULL; /* no struct yet */
 }
 #endif /* CURLRES_ARES */
	/***************************************************************************
	* _ _ ____ _
	* Project ___\| \| \| \| _ \\| \|
	* / __\| \| \| \| \|_) \| \|
	* \| (__\| \|_\| \| _ <\| \|___
	* \___\|\___/\|_\| \_\_____\|
	*
	* Copyright (C) 1998 - 2011, Daniel Stenberg, <daniel@haxx.se>, et al.
	*
	* This software is licensed as described in the file COPYING, which
	* you should have received as part of this distribution. The terms
	* are also available at http://curl.haxx.se/docs/copyright.html.
	*
	* You may opt to use, copy, modify, merge, publish, distribute and/or sell
	* copies of the Software, and permit persons to whom the Software is
	* furnished to do so, under the terms of the COPYING file.
	*
	* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
	* KIND, either express or implied.
	*
	***************************************************************************/

	#include "setup.h"

	#include <string.h>

	#ifdef HAVE_LIMITS_H
	#include <limits.h>
	#endif
	#ifdef HAVE_SYS_SOCKET_H
	#include <sys/socket.h>
	#endif
	#ifdef HAVE_NETINET_IN_H
	#include <netinet/in.h>
	#endif
	#ifdef HAVE_NETDB_H
	#include <netdb.h>
	#endif
	#ifdef HAVE_ARPA_INET_H
	#include <arpa/inet.h>
	#endif
	#ifdef HAVE_STDLIB_H
	#include <stdlib.h> /* required for free() prototypes */
	#endif
	#ifdef HAVE_UNISTD_H
	#include <unistd.h> /* for the close() proto */
	#endif
	#ifdef __VMS
	#include <in.h>
	#include <inet.h>
	#include <stdlib.h>
	#endif

	#ifdef HAVE_PROCESS_H
	#include <process.h>
	#endif

	#if (defined(NETWARE) && defined(__NOVELL_LIBC__))
	#undef in_addr_t
	#define in_addr_t unsigned long
	#endif

	#include "urldata.h"
	#include "sendf.h"
	#include "hostip.h"
	#include "hash.h"
	#include "share.h"
	#include "strerror.h"
	#include "url.h"
	#include "multiif.h"
	#include "inet_pton.h"
	#include "connect.h"
	#include "select.h"
	#include "progress.h"

	#define _MPRINTF_REPLACE /* use our functions only */
	#include <curl/mprintf.h>

	#include "curl_memory.h"
	/* The last #include file should be: */
	#include "memdebug.h"

	/***********************************************************************
	* Only for ares-enabled builds
	**********************************************************************/

	#ifdef CURLRES_ARES

	/*
	* Curl_resolv_fdset() is called when someone from the outside world (using
	* curl_multi_fdset()) wants to get our fd_set setup and we're talking with
	* ares. The caller must make sure that this function is only called when we
	* have a working ares channel.
	*
	* Returns: CURLE_OK always!
	*/

	int Curl_resolv_getsock(struct connectdata *conn,
	curl_socket_t *socks,
	int numsocks)

	{
	struct timeval maxtime;
	struct timeval timebuf;
	struct timeval *timeout;
	int max = ares_getsock(conn->data->state.areschannel,
	(ares_socket_t *)socks, numsocks);


	maxtime.tv_sec = CURL_TIMEOUT_RESOLVE;
	maxtime.tv_usec = 0;

	timeout = ares_timeout(conn->data->state.areschannel, &maxtime, &timebuf);

	Curl_expire(conn->data,
	(timeout->tv_sec * 1000) + (timeout->tv_usec/1000));

	return max;
	}

	/*
	* waitperform()
	*
	* 1) Ask ares what sockets it currently plays with, then
	* 2) wait for the timeout period to check for action on ares' sockets.
	* 3) tell ares to act on all the sockets marked as "with action"
	*
	* return number of sockets it worked on
	*/

	static int waitperform(struct connectdata *conn, int timeout_ms)
	{
	struct SessionHandle *data = conn->data;
	int nfds;
	int bitmask;
	ares_socket_t socks[ARES_GETSOCK_MAXNUM];
	struct pollfd pfd[ARES_GETSOCK_MAXNUM];
	int i;
	int num = 0;

	bitmask = ares_getsock(data->state.areschannel, socks, ARES_GETSOCK_MAXNUM);

	for(i=0; i < ARES_GETSOCK_MAXNUM; i++) {
	pfd[i].events = 0;
	pfd[i].revents = 0;
	if(ARES_GETSOCK_READABLE(bitmask, i)) {
	pfd[i].fd = socks[i];
	pfd[i].events \|= POLLRDNORM\|POLLIN;
	}
	if(ARES_GETSOCK_WRITABLE(bitmask, i)) {
	pfd[i].fd = socks[i];
	pfd[i].events \|= POLLWRNORM\|POLLOUT;
	}
	if(pfd[i].events != 0)
	num++;
	else
	break;
	}

	if(num)
	nfds = Curl_poll(pfd, num, timeout_ms);
	else
	nfds = 0;

	if(!nfds)
	/* Call ares_process() unconditonally here, even if we simply timed out
	above, as otherwise the ares name resolve won't timeout! */
	ares_process_fd(data->state.areschannel, ARES_SOCKET_BAD, ARES_SOCKET_BAD);
	else {
	/* move through the descriptors and ask for processing on them */
	for(i=0; i < num; i++)
	ares_process_fd(data->state.areschannel,
	pfd[i].revents & (POLLRDNORM\|POLLIN)?
	pfd[i].fd:ARES_SOCKET_BAD,
	pfd[i].revents & (POLLWRNORM\|POLLOUT)?
	pfd[i].fd:ARES_SOCKET_BAD);
	}
	return nfds;
	}

	/*
	* Curl_is_resolved() is called repeatedly to check if a previous name resolve
	* request has completed. It should also make sure to time-out if the
	* operation seems to take too long.
	*
	* Returns normal CURLcode errors.
	*/
	CURLcode Curl_is_resolved(struct connectdata *conn,
	struct Curl_dns_entry **dns)
	{
	struct SessionHandle *data = conn->data;

	*dns = NULL;

	waitperform(conn, 0);

	if(conn->async.done) {
	/* we're done, kill the ares handle */
	if(!conn->async.dns) {
	failf(data, "Could not resolve host: %s (%s)", conn->host.dispname,
	ares_strerror(conn->async.status));
	return CURLE_COULDNT_RESOLVE_HOST;
	}
	*dns = conn->async.dns;
	}

	return CURLE_OK;
	}

	/*
	* Curl_wait_for_resolv() waits for a resolve to finish. This function should
	* be avoided since using this risk getting the multi interface to "hang".
	*
	* If 'entry' is non-NULL, make it point to the resolved dns entry
	*
	* Returns CURLE_COULDNT_RESOLVE_HOST if the host was not resolved, and
	* CURLE_OPERATION_TIMEDOUT if a time-out occurred.
	*/
	CURLcode Curl_wait_for_resolv(struct connectdata *conn,
	struct Curl_dns_entry **entry)
	{
	CURLcode rc=CURLE_OK;
	struct SessionHandle *data = conn->data;
	long timeout;
	struct timeval now = Curl_tvnow();

	timeout = Curl_timeleft(data, &now, TRUE);
	if(!timeout)
	timeout = CURL_TIMEOUT_RESOLVE * 1000; /* default name resolve timeout */

	/* Wait for the name resolve query to complete. */
	for(;;) {
	struct timeval *tvp, tv, store;
	long timediff;
	int itimeout;
	int timeout_ms;

	itimeout = (timeout > (long)INT_MAX) ? INT_MAX : (int)timeout;

	store.tv_sec = itimeout/1000;
	store.tv_usec = (itimeout%1000)*1000;

	tvp = ares_timeout(data->state.areschannel, &store, &tv);

	/* use the timeout period ares returned to us above if less than one
	second is left, otherwise just use 1000ms to make sure the progress
	callback gets called frequent enough */
	if(!tvp->tv_sec)
	timeout_ms = (int)(tvp->tv_usec/1000);
	else
	timeout_ms = 1000;

	waitperform(conn, timeout_ms);

	if(conn->async.done)
	break;

	if(Curl_pgrsUpdate(conn)) {
	rc = CURLE_ABORTED_BY_CALLBACK;
	timeout = -1; /* trigger the cancel below */
	}
	else {
	struct timeval now2 = Curl_tvnow();
	timediff = Curl_tvdiff(now2, now); /* spent time */
	timeout -= timediff?timediff:1; /* always deduct at least 1 */
	now = now2; /* for next loop */
	}
	if(timeout < 0) {
	/* our timeout, so we cancel the ares operation */
	ares_cancel(data->state.areschannel);
	break;
	}
	}

	/* Operation complete, if the lookup was successful we now have the entry
	in the cache. */

	if(entry)
	*entry = conn->async.dns;

	if(!conn->async.dns) {
	/* a name was not resolved */
	if((timeout < 0) \|\| (conn->async.status == ARES_ETIMEOUT)) {
	if (conn->bits.httpproxy) {
	failf(data, "Resolving proxy timed out: %s", conn->proxy.dispname);
	rc = CURLE_COULDNT_RESOLVE_PROXY;
	}
	else {
	failf(data, "Resolving host timed out: %s", conn->host.dispname);
	rc = CURLE_COULDNT_RESOLVE_HOST;
	}
	}
	else if(conn->async.done) {
	if (conn->bits.httpproxy) {
	failf(data, "Could not resolve proxy: %s (%s)", conn->proxy.dispname,
	ares_strerror(conn->async.status));
	rc = CURLE_COULDNT_RESOLVE_PROXY;
	}
	else {
	failf(data, "Could not resolve host: %s (%s)", conn->host.dispname,
	ares_strerror(conn->async.status));
	rc = CURLE_COULDNT_RESOLVE_HOST;
	}
	}
	else
	rc = CURLE_OPERATION_TIMEDOUT;

	/* close the connection, since we can't return failure here without
	cleaning up this connection properly */
	conn->bits.close = TRUE;
	}

	return rc;
	}

	/*
	* ares_query_completed_cb() is the callback that ares will call when
	* the host query initiated by ares_gethostbyname() from Curl_getaddrinfo(),
	* when using ares, is completed either successfully or with failure.
	*/
	static void ares_query_completed_cb(void arg, / (struct connectdata ) /
	int status,
	#ifdef HAVE_CARES_CALLBACK_TIMEOUTS
	int timeouts,
	#endif
	struct hostent *hostent)
	{
	struct connectdata conn = (struct connectdata )arg;
	struct Curl_addrinfo * ai = NULL;

	#ifdef HAVE_CARES_CALLBACK_TIMEOUTS
	(void)timeouts; /* ignored */
	#endif

	switch(status) {
	case CURL_ASYNC_SUCCESS:
	ai = Curl_he2ai(hostent, conn->async.port);
	break;
	case ARES_EDESTRUCTION:
	/* this ares handle is getting destroyed, the 'arg' pointer may not be
	valid! */
	return;
	default:
	/* do nothing */
	break;
	}

	(void)Curl_addrinfo_callback(arg, status, ai);
	}

	/*
	* Curl_getaddrinfo() - when using ares
	*
	* Returns name information about the given hostname and port number. If
	* successful, the 'hostent' is returned and the forth argument will point to
	* memory we need to free after use. That memory MUST be freed with
	* Curl_freeaddrinfo(), nothing else.
	*/
	Curl_addrinfo Curl_getaddrinfo(struct connectdata conn,
	const char *hostname,
	int port,
	int *waitp)
	{
	char *bufp;
	struct SessionHandle *data = conn->data;
	struct in_addr in;
	int family = PF_INET;
	#ifdef ENABLE_IPV6 /* CURLRES_IPV6 */
	struct in6_addr in6;
	#endif /* CURLRES_IPV6 */

	waitp = 0; / default to synchronous response */

	/* First check if this is an IPv4 address string */
	if(Curl_inet_pton(AF_INET, hostname, &in) > 0) {
	/* This is a dotted IP address 123.123.123.123-style */
	return Curl_ip2addr(AF_INET, &in, hostname, port);
	}

	#ifdef ENABLE_IPV6 /* CURLRES_IPV6 */
	/* Otherwise, check if this is an IPv6 address string */
	if (Curl_inet_pton (AF_INET6, hostname, &in6) > 0) {
	/* This must be an IPv6 address literal. */
	return Curl_ip2addr(AF_INET6, &in6, hostname, port);
	}

	switch(conn->ip_version) {
	default:
	#if ARES_VERSION >= 0x010601
	family = PF_UNSPEC; /* supported by c-ares since 1.6.1, so for older
	c-ares versions this just falls through and defaults
	to PF_INET */
	break;
	#endif
	case CURL_IPRESOLVE_V4:
	family = PF_INET;
	break;
	case CURL_IPRESOLVE_V6:
	family = PF_INET6;
	break;
	}
	#endif /* CURLRES_IPV6 */

	bufp = strdup(hostname);

	if(bufp) {
	Curl_safefree(conn->async.hostname);
	conn->async.hostname = bufp;
	conn->async.port = port;
	conn->async.done = FALSE; /* not done */
	conn->async.status = 0; /* clear */
	conn->async.dns = NULL; /* clear */
	conn->async.temp_ai = NULL; /* clear */

	#ifdef ENABLE_IPV6 /* CURLRES_IPV6 */
	if(family == PF_UNSPEC) {
	conn->async.num_pending = 2;

	/* areschannel is already setup in the Curl_open() function */
	ares_gethostbyname(data->state.areschannel, hostname, PF_INET,
	ares_query_completed_cb, conn);
	ares_gethostbyname(data->state.areschannel, hostname, PF_INET6,
	ares_query_completed_cb, conn);
	}
	else
	#endif /* CURLRES_IPV6 */
	{
	conn->async.num_pending = 1;

	/* areschannel is already setup in the Curl_open() function */
	ares_gethostbyname(data->state.areschannel, hostname, family,
	ares_query_completed_cb, conn);
	}

	waitp = 1; / expect asynchronous response */
	}
	return NULL; /* no struct yet */
	}
	#endif /* CURLRES_ARES */