CMakeLua/Utilities/cmcurl-7.19.0/lib/hostip.c

   1 /***************************************************************************
   2  *                                  _   _ ____  _
   3  *  Project                     ___| | | |  _ \| |
   4  *                             / __| | | | |_) | |
   5  *                            | (__| |_| |  _ <| |___
   6  *                             \___|\___/|_| \_\_____|
   7  *
   8  * Copyright (C) 1998 - 2008, Daniel Stenberg, <daniel@haxx.se>, et al.
   9  *
  10  * This software is licensed as described in the file COPYING, which
  11  * you should have received as part of this distribution. The terms
  12  * are also available at http://curl.haxx.se/docs/copyright.html.
  13  *
  14  * You may opt to use, copy, modify, merge, publish, distribute and/or sell
  15  * copies of the Software, and permit persons to whom the Software is
  16  * furnished to do so, under the terms of the COPYING file.
  17  *
  18  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  19  * KIND, either express or implied.
  20  *
  21  * $Id: hostip.c,v 1.1.1.1 2008-09-23 16:32:05 hoffman Exp $
  22  ***************************************************************************/
  23
  24 #include "setup.h"
  25
  26 #include <string.h>
  27
  28 #ifdef NEED_MALLOC_H
  29 #include <malloc.h>
  30 #endif
  31 #ifdef HAVE_SYS_SOCKET_H
  32 #include <sys/socket.h>
  33 #endif
  34 #ifdef HAVE_NETINET_IN_H
  35 #include <netinet/in.h>
  36 #endif
  37 #ifdef HAVE_NETDB_H
  38 #include <netdb.h>
  39 #endif
  40 #ifdef HAVE_ARPA_INET_H
  41 #include <arpa/inet.h>
  42 #endif
  43 #ifdef HAVE_STDLIB_H
  44 #include <stdlib.h>     /* required for free() prototypes */
  45 #endif
  46 #ifdef HAVE_UNISTD_H
  47 #include <unistd.h>     /* for the close() proto */
  48 #endif
  49 #ifdef  VMS
  50 #include <in.h>
  51 #include <inet.h>
  52 #include <stdlib.h>
  53 #endif
  54
  55 #ifdef HAVE_SETJMP_H
  56 #include <setjmp.h>
  57 #endif
  58
  59 #ifdef HAVE_PROCESS_H
  60 #include <process.h>
  61 #endif
  62
  63 #include "urldata.h"
  64 #include "sendf.h"
  65 #include "hostip.h"
  66 #include "hash.h"
  67 #include "share.h"
  68 #include "strerror.h"
  69 #include "url.h"
  70 #include "inet_ntop.h"
  71
  72 #define _MPRINTF_REPLACE /* use our functions only */
  73 #include <curl/mprintf.h>
  74
  75 #if defined(HAVE_INET_NTOA_R) && !defined(HAVE_INET_NTOA_R_DECL)
  76 #include "inet_ntoa_r.h"
  77 #endif
  78
  79 #include "memory.h"
  80 /* The last #include file should be: */
  81 #include "memdebug.h"
  82
  83 /*
  84  * hostip.c explained
  85  * ==================
  86  *
  87  * The main COMPILE-TIME DEFINES to keep in mind when reading the host*.c
  88  * source file are these:
  89  *
  90  * CURLRES_IPV6 - this host has getaddrinfo() and family, and thus we use
  91  * that. The host may not be able to resolve IPv6, but we don't really have to
  92  * take that into account. Hosts that aren't IPv6-enabled have CURLRES_IPV4
  93  * defined.
  94  *
  95  * CURLRES_ARES - is defined if libcurl is built to use c-ares for
  96  * asynchronous name resolves. This can be Windows or *nix.
  97  *
  98  * CURLRES_THREADED - is defined if libcurl is built to run under (native)
  99  * Windows, and then the name resolve will be done in a new thread, and the
 100  * supported API will be the same as for ares-builds.
 101  *
 102  * If any of the two previous are defined, CURLRES_ASYNCH is defined too. If
 103  * libcurl is not built to use an asynchronous resolver, CURLRES_SYNCH is
 104  * defined.
 105  *
 106  * The host*.c sources files are split up like this:
 107  *
 108  * hostip.c   - method-independent resolver functions and utility functions
 109  * hostasyn.c - functions for asynchronous name resolves
 110  * hostsyn.c  - functions for synchronous name resolves
 111  * hostares.c - functions for ares-using name resolves
 112  * hostthre.c - functions for threaded name resolves
 113  * hostip4.c  - ipv4-specific functions
 114  * hostip6.c  - ipv6-specific functions
 115  *
 116  * The hostip.h is the united header file for all this. It defines the
 117  * CURLRES_* defines based on the config*.h and setup.h defines.
 118  */
 119
 120 /* These two symbols are for the global DNS cache */
 121 static struct curl_hash hostname_cache;
 122 static int host_cache_initialized;
 123
 124 static void freednsentry(void *freethis);
 125
 126 /*
 127  * Curl_global_host_cache_init() initializes and sets up a global DNS cache.
 128  * Global DNS cache is general badness. Do not use. This will be removed in
 129  * a future version. Use the share interface instead!
 130  *
 131  * Returns a struct curl_hash pointer on success, NULL on failure.
 132  */
 133 struct curl_hash *Curl_global_host_cache_init(void)
 134 {
 135   int rc = 0;
 136   if(!host_cache_initialized) {
 137     rc = Curl_hash_init(&hostname_cache, 7, Curl_hash_str,
 138                         Curl_str_key_compare, freednsentry);
 139     if(!rc)
 140       host_cache_initialized = 1;
 141   }
 142   return rc?NULL:&hostname_cache;
 143 }
 144
 145 /*
 146  * Destroy and cleanup the global DNS cache
 147  */
 148 void Curl_global_host_cache_dtor(void)
 149 {
 150   if(host_cache_initialized) {
 151     Curl_hash_clean(&hostname_cache);
 152     host_cache_initialized = 0;
 153   }
 154 }
 155
 156 /*
 157  * Return # of adresses in a Curl_addrinfo struct
 158  */
 159 int Curl_num_addresses(const Curl_addrinfo *addr)
 160 {
 161   int i;
 162   for (i = 0; addr; addr = addr->ai_next, i++)
 163     ;  /* empty loop */
 164   return i;
 165 }
 166
 167 /*
 168  * Curl_printable_address() returns a printable version of the 1st address
 169  * given in the 'ip' argument. The result will be stored in the buf that is
 170  * bufsize bytes big.
 171  *
 172  * If the conversion fails, it returns NULL.
 173  */
 174 const char *Curl_printable_address(const Curl_addrinfo *ip,
 175                                    char *buf, size_t bufsize)
 176 {
 177   const void *ip4 = &((const struct sockaddr_in*)ip->ai_addr)->sin_addr;
 178   int af = ip->ai_family;
 179 #ifdef CURLRES_IPV6
 180   const void *ip6 = &((const struct sockaddr_in6*)ip->ai_addr)->sin6_addr;
 181 #else
 182   const void *ip6 = NULL;
 183 #endif
 184
 185   return Curl_inet_ntop(af, af == AF_INET ? ip4 : ip6, buf, bufsize);
 186 }
 187
 188 /*
 189  * Return a hostcache id string for the providing host + port, to be used by
 190  * the DNS caching.
 191  */
 192 static char *
 193 create_hostcache_id(const char *server, int port)
 194 {
 195   /* create and return the new allocated entry */
 196   return aprintf("%s:%d", server, port);
 197 }
 198
 199 struct hostcache_prune_data {
 200   long cache_timeout;
 201   time_t now;
 202 };
 203
 204 /*
 205  * This function is set as a callback to be called for every entry in the DNS
 206  * cache when we want to prune old unused entries.
 207  *
 208  * Returning non-zero means remove the entry, return 0 to keep it in the
 209  * cache.
 210  */
 211 static int
 212 hostcache_timestamp_remove(void *datap, void *hc)
 213 {
 214   struct hostcache_prune_data *data =
 215     (struct hostcache_prune_data *) datap;
 216   struct Curl_dns_entry *c = (struct Curl_dns_entry *) hc;
 217
 218   if((data->now - c->timestamp < data->cache_timeout) ||
 219       c->inuse) {
 220     /* please don't remove */
 221     return 0;
 222   }
 223
 224   /* fine, remove */
 225   return 1;
 226 }
 227
 228 /*
 229  * Prune the DNS cache. This assumes that a lock has already been taken.
 230  */
 231 static void
 232 hostcache_prune(struct curl_hash *hostcache, long cache_timeout, time_t now)
 233 {
 234   struct hostcache_prune_data user;
 235
 236   user.cache_timeout = cache_timeout;
 237   user.now = now;
 238
 239   Curl_hash_clean_with_criterium(hostcache,
 240                                  (void *) &user,
 241                                  hostcache_timestamp_remove);
 242 }
 243
 244 /*
 245  * Library-wide function for pruning the DNS cache. This function takes and
 246  * returns the appropriate locks.
 247  */
 248 void Curl_hostcache_prune(struct SessionHandle *data)
 249 {
 250   time_t now;
 251
 252   if((data->set.dns_cache_timeout == -1) || !data->dns.hostcache)
 253     /* cache forever means never prune, and NULL hostcache means
 254        we can't do it */
 255     return;
 256
 257   if(data->share)
 258     Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE);
 259
 260   time(&now);
 261
 262   /* Remove outdated and unused entries from the hostcache */
 263   hostcache_prune(data->dns.hostcache,
 264                   data->set.dns_cache_timeout,
 265                   now);
 266
 267   if(data->share)
 268     Curl_share_unlock(data, CURL_LOCK_DATA_DNS);
 269 }
 270
 271 /*
 272  * Check if the entry should be pruned. Assumes a locked cache.
 273  */
 274 static int
 275 remove_entry_if_stale(struct SessionHandle *data, struct Curl_dns_entry *dns)
 276 {
 277   struct hostcache_prune_data user;
 278
 279   if( !dns || (data->set.dns_cache_timeout == -1) || !data->dns.hostcache)
 280     /* cache forever means never prune, and NULL hostcache means
 281        we can't do it */
 282     return 0;
 283
 284   time(&user.now);
 285   user.cache_timeout = data->set.dns_cache_timeout;
 286
 287   if( !hostcache_timestamp_remove(&user,dns) )
 288     return 0;
 289
 290   Curl_hash_clean_with_criterium(data->dns.hostcache,
 291                                  (void *) &user,
 292                                  hostcache_timestamp_remove);
 293
 294   return 1;
 295 }
 296
 297
 298 #ifdef HAVE_SIGSETJMP
 299 /* Beware this is a global and unique instance. This is used to store the
 300    return address that we can jump back to from inside a signal handler. This
 301    is not thread-safe stuff. */
 302 sigjmp_buf curl_jmpenv;
 303 #endif
 304
 305
 306 /*
 307  * Curl_cache_addr() stores a 'Curl_addrinfo' struct in the DNS cache.
 308  *
 309  * When calling Curl_resolv() has resulted in a response with a returned
 310  * address, we call this function to store the information in the dns
 311  * cache etc
 312  *
 313  * Returns the Curl_dns_entry entry pointer or NULL if the storage failed.
 314  */
 315 struct Curl_dns_entry *
 316 Curl_cache_addr(struct SessionHandle *data,
 317                 Curl_addrinfo *addr,
 318                 const char *hostname,
 319                 int port)
 320 {
 321   char *entry_id;
 322   size_t entry_len;
 323   struct Curl_dns_entry *dns;
 324   struct Curl_dns_entry *dns2;
 325   time_t now;
 326
 327   /* Create an entry id, based upon the hostname and port */
 328   entry_id = create_hostcache_id(hostname, port);
 329   /* If we can't create the entry id, fail */
 330   if(!entry_id)
 331     return NULL;
 332   entry_len = strlen(entry_id);
 333
 334   /* Create a new cache entry */
 335   dns = (struct Curl_dns_entry *) calloc(sizeof(struct Curl_dns_entry), 1);
 336   if(!dns) {
 337     free(entry_id);
 338     return NULL;
 339   }
 340
 341   dns->inuse = 0;   /* init to not used */
 342   dns->addr = addr; /* this is the address(es) */
 343
 344   /* Store the resolved data in our DNS cache. This function may return a
 345      pointer to an existing struct already present in the hash, and it may
 346      return the same argument we pass in. Make no assumptions. */
 347   dns2 = Curl_hash_add(data->dns.hostcache, entry_id, entry_len+1,
 348                        (void *)dns);
 349   if(!dns2) {
 350     /* Major badness, run away. */
 351     free(dns);
 352     free(entry_id);
 353     return NULL;
 354   }
 355   time(&now);
 356   dns = dns2;
 357
 358   dns->timestamp = now; /* used now */
 359   dns->inuse++;         /* mark entry as in-use */
 360
 361   /* free the allocated entry_id again */
 362   free(entry_id);
 363
 364   return dns;
 365 }
 366
 367 /*
 368  * Curl_resolv() is the main name resolve function within libcurl. It resolves
 369  * a name and returns a pointer to the entry in the 'entry' argument (if one
 370  * is provided). This function might return immediately if we're using asynch
 371  * resolves. See the return codes.
 372  *
 373  * The cache entry we return will get its 'inuse' counter increased when this
 374  * function is used. You MUST call Curl_resolv_unlock() later (when you're
 375  * done using this struct) to decrease the counter again.
 376  *
 377  * Return codes:
 378  *
 379  * CURLRESOLV_ERROR   (-1) = error, no pointer
 380  * CURLRESOLV_RESOLVED (0) = OK, pointer provided
 381  * CURLRESOLV_PENDING  (1) = waiting for response, no pointer
 382  */
 383
 384 int Curl_resolv(struct connectdata *conn,
 385                 const char *hostname,
 386                 int port,
 387                 struct Curl_dns_entry **entry)
 388 {
 389   char *entry_id = NULL;
 390   struct Curl_dns_entry *dns = NULL;
 391   size_t entry_len;
 392   struct SessionHandle *data = conn->data;
 393   CURLcode result;
 394   int rc = CURLRESOLV_ERROR; /* default to failure */
 395   *entry = NULL;
 396
 397 #ifdef HAVE_SIGSETJMP
 398   /* this allows us to time-out from the name resolver, as the timeout
 399      will generate a signal and we will siglongjmp() from that here */
 400   if(!data->set.no_signal) {
 401     if(sigsetjmp(curl_jmpenv, 1)) {
 402       /* this is coming from a siglongjmp() */
 403       failf(data, "name lookup timed out");
 404       return rc;
 405     }
 406   }
 407 #endif
 408
 409   /* Create an entry id, based upon the hostname and port */
 410   entry_id = create_hostcache_id(hostname, port);
 411   /* If we can't create the entry id, fail */
 412   if(!entry_id)
 413     return rc;
 414
 415   entry_len = strlen(entry_id);
 416
 417   if(data->share)
 418     Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE);
 419
 420   /* See if its already in our dns cache */
 421   dns = Curl_hash_pick(data->dns.hostcache, entry_id, entry_len+1);
 422
 423   /* See whether the returned entry is stale. Done before we release lock */
 424   if( remove_entry_if_stale(data, dns) )
 425     dns = NULL; /* the memory deallocation is being handled by the hash */
 426
 427   if(dns) {
 428     dns->inuse++; /* we use it! */
 429     rc = CURLRESOLV_RESOLVED;
 430   }
 431
 432   if(data->share)
 433     Curl_share_unlock(data, CURL_LOCK_DATA_DNS);
 434
 435   /* free the allocated entry_id again */
 436   free(entry_id);
 437
 438   if(!dns) {
 439     /* The entry was not in the cache. Resolve it to IP address */
 440
 441     Curl_addrinfo *addr;
 442     int respwait;
 443
 444     /* Check what IP specifics the app has requested and if we can provide it.
 445      * If not, bail out. */
 446     if(!Curl_ipvalid(data))
 447       return CURLRESOLV_ERROR;
 448
 449     /* If Curl_getaddrinfo() returns NULL, 'respwait' might be set to a
 450        non-zero value indicating that we need to wait for the response to the
 451        resolve call */
 452     addr = Curl_getaddrinfo(conn, hostname, port, &respwait);
 453
 454     if(!addr) {
 455       if(respwait) {
 456         /* the response to our resolve call will come asynchronously at
 457            a later time, good or bad */
 458         /* First, check that we haven't received the info by now */
 459         result = Curl_is_resolved(conn, &dns);
 460         if(result) /* error detected */
 461           return CURLRESOLV_ERROR;
 462         if(dns)
 463           rc = CURLRESOLV_RESOLVED; /* pointer provided */
 464         else
 465           rc = CURLRESOLV_PENDING; /* no info yet */
 466       }
 467     }
 468     else {
 469       if(data->share)
 470         Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE);
 471
 472       /* we got a response, store it in the cache */
 473       dns = Curl_cache_addr(data, addr, hostname, port);
 474
 475       if(data->share)
 476         Curl_share_unlock(data, CURL_LOCK_DATA_DNS);
 477
 478       if(!dns)
 479         /* returned failure, bail out nicely */
 480         Curl_freeaddrinfo(addr);
 481       else
 482         rc = CURLRESOLV_RESOLVED;
 483     }
 484   }
 485
 486   *entry = dns;
 487
 488   return rc;
 489 }
 490
 491 /*
 492  * Curl_resolv_unlock() unlocks the given cached DNS entry. When this has been
 493  * made, the struct may be destroyed due to pruning. It is important that only
 494  * one unlock is made for each Curl_resolv() call.
 495  */
 496 void Curl_resolv_unlock(struct SessionHandle *data, struct Curl_dns_entry *dns)
 497 {
 498   DEBUGASSERT(dns && (dns->inuse>0));
 499
 500   if(data->share)
 501     Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE);
 502
 503   dns->inuse--;
 504
 505   if(data->share)
 506     Curl_share_unlock(data, CURL_LOCK_DATA_DNS);
 507 }
 508
 509 /*
 510  * File-internal: free a cache dns entry.
 511  */
 512 static void freednsentry(void *freethis)
 513 {
 514   struct Curl_dns_entry *p = (struct Curl_dns_entry *) freethis;
 515
 516   Curl_freeaddrinfo(p->addr);
 517
 518   free(p);
 519 }
 520
 521 /*
 522  * Curl_mk_dnscache() creates a new DNS cache and returns the handle for it.
 523  */
 524 struct curl_hash *Curl_mk_dnscache(void)
 525 {
 526   return Curl_hash_alloc(7, Curl_hash_str, Curl_str_key_compare, freednsentry);
 527 }
 528
 529 #ifdef CURLRES_ADDRINFO_COPY
 530
 531 /* align on even 64bit boundaries */
 532 #define MEMALIGN(x) ((x)+(8-(((unsigned long)(x))&0x7)))
 533
 534 /*
 535  * Curl_addrinfo_copy() performs a "deep" copy of a hostent into a buffer and
 536  * returns a pointer to the malloc()ed copy. You need to call free() on the
 537  * returned buffer when you're done with it.
 538  */
 539 Curl_addrinfo *Curl_addrinfo_copy(const void *org, int port)
 540 {
 541   const struct hostent *orig = org;
 542
 543   return Curl_he2ai(orig, port);
 544 }
 545 #endif /* CURLRES_ADDRINFO_COPY */
 546
 547 /***********************************************************************
 548  * Only for plain-ipv4 and c-ares builds (NOTE: c-ares builds can be IPv6
 549  * enabled)
 550  **********************************************************************/
 551
 552 #if defined(CURLRES_IPV4) || defined(CURLRES_ARES)
 553 /*
 554  * This is a function for freeing name information in a protocol independent
 555  * way.
 556  */
 557 void Curl_freeaddrinfo(Curl_addrinfo *ai)
 558 {
 559   Curl_addrinfo *next;
 560
 561   /* walk over the list and free all entries */
 562   while(ai) {
 563     next = ai->ai_next;
 564     if(ai->ai_canonname)
 565       free(ai->ai_canonname);
 566     free(ai);
 567     ai = next;
 568   }
 569 }
 570
 571 struct namebuf {
 572   struct hostent hostentry;
 573   char *h_addr_list[2];
 574   struct in_addr addrentry;
 575   char h_name[16]; /* 123.123.123.123 = 15 letters is maximum */
 576 };
 577
 578 /*
 579  * Curl_ip2addr() takes a 32bit ipv4 internet address as input parameter
 580  * together with a pointer to the string version of the address, and it
 581  * returns a Curl_addrinfo chain filled in correctly with information for this
 582  * address/host.
 583  *
 584  * The input parameters ARE NOT checked for validity but they are expected
 585  * to have been checked already when this is called.
 586  */
 587 Curl_addrinfo *Curl_ip2addr(in_addr_t num, const char *hostname, int port)
 588 {
 589   Curl_addrinfo *ai;
 590
 591 #if defined(VMS) && \
 592     defined(__INITIAL_POINTER_SIZE) && (__INITIAL_POINTER_SIZE == 64)
 593 #pragma pointer_size save
 594 #pragma pointer_size short
 595 #pragma message disable PTRMISMATCH
 596 #endif
 597
 598   struct hostent *h;
 599   struct in_addr *addrentry;
 600   struct namebuf buffer;
 601   struct namebuf *buf = &buffer;
 602
 603   h = &buf->hostentry;
 604   h->h_addr_list = &buf->h_addr_list[0];
 605   addrentry = &buf->addrentry;
 606 #ifdef _CRAYC
 607   /* On UNICOS, s_addr is a bit field and for some reason assigning to it
 608    * doesn't work.  There must be a better fix than this ugly hack.
 609    */
 610   memcpy(addrentry, &num, SIZEOF_in_addr);
 611 #else
 612   addrentry->s_addr = num;
 613 #endif
 614   h->h_addr_list[0] = (char*)addrentry;
 615   h->h_addr_list[1] = NULL;
 616   h->h_addrtype = AF_INET;
 617   h->h_length = sizeof(*addrentry);
 618   h->h_name = &buf->h_name[0];
 619   h->h_aliases = NULL;
 620
 621   /* Now store the dotted version of the address */
 622   snprintf((char *)h->h_name, 16, "%s", hostname);
 623
 624 #if defined(VMS) && \
 625     defined(__INITIAL_POINTER_SIZE) && (__INITIAL_POINTER_SIZE == 64)
 626 #pragma pointer_size restore
 627 #pragma message enable PTRMISMATCH
 628 #endif
 629
 630   ai = Curl_he2ai(h, port);
 631
 632   return ai;
 633 }
 634
 635 /*
 636  * Curl_he2ai() translates from a hostent struct to a Curl_addrinfo struct.
 637  * The Curl_addrinfo is meant to work like the addrinfo struct does for IPv6
 638  * stacks, but for all hosts and environments.
 639  *
 640  *   Curl_addrinfo defined in "lib/hostip.h"
 641  *
 642  *     struct Curl_addrinfo {
 643  *       int                   ai_flags;
 644  *       int                   ai_family;
 645  *       int                   ai_socktype;
 646  *       int                   ai_protocol;
 647  *       socklen_t             ai_addrlen;   * Follow rfc3493 struct addrinfo *
 648  *       char                 *ai_canonname;
 649  *       struct sockaddr      *ai_addr;
 650  *       struct Curl_addrinfo *ai_next;
 651  *     };
 652  *
 653  *   hostent defined in <netdb.h>
 654  *
 655  *     struct hostent {
 656  *       char    *h_name;
 657  *       char    **h_aliases;
 658  *       int     h_addrtype;
 659  *       int     h_length;
 660  *       char    **h_addr_list;
 661  *     };
 662  *
 663  *   for backward compatibility:
 664  *
 665  *     #define h_addr  h_addr_list[0]
 666  */
 667
 668 Curl_addrinfo *Curl_he2ai(const struct hostent *he, int port)
 669 {
 670   Curl_addrinfo *ai;
 671   Curl_addrinfo *prevai = NULL;
 672   Curl_addrinfo *firstai = NULL;
 673   struct sockaddr_in *addr;
 674 #ifdef CURLRES_IPV6
 675   struct sockaddr_in6 *addr6;
 676 #endif /* CURLRES_IPV6 */
 677   int i;
 678   struct in_addr *curr;
 679
 680   if(!he)
 681     /* no input == no output! */
 682     return NULL;
 683
 684   for(i=0; (curr = (struct in_addr *)he->h_addr_list[i]) != NULL; i++) {
 685
 686     int ss_size;
 687 #ifdef CURLRES_IPV6
 688     if (he->h_addrtype == AF_INET6)
 689       ss_size = sizeof (struct sockaddr_in6);
 690     else
 691 #endif /* CURLRES_IPV6 */
 692       ss_size = sizeof (struct sockaddr_in);
 693
 694     ai = calloc(1, sizeof(Curl_addrinfo) + ss_size);
 695
 696     if(!ai)
 697       break;
 698
 699     if(!firstai)
 700       /* store the pointer we want to return from this function */
 701       firstai = ai;
 702
 703     if(prevai)
 704       /* make the previous entry point to this */
 705       prevai->ai_next = ai;
 706
 707     ai->ai_family = he->h_addrtype;
 708
 709     /* we return all names as STREAM, so when using this address for TFTP
 710        the type must be ignored and conn->socktype be used instead! */
 711     ai->ai_socktype = SOCK_STREAM;
 712
 713     ai->ai_addrlen = ss_size;
 714     /* make the ai_addr point to the address immediately following this struct
 715        and use that area to store the address */
 716     ai->ai_addr = (struct sockaddr *) ((char*)ai + sizeof(Curl_addrinfo));
 717
 718     /* need to free this eventually */
 719     ai->ai_canonname = strdup(he->h_name);
 720
 721     /* leave the rest of the struct filled with zero */
 722
 723     switch (ai->ai_family) {
 724     case AF_INET:
 725       addr = (struct sockaddr_in *)ai->ai_addr; /* storage area for this info */
 726
 727       memcpy((char *)&(addr->sin_addr), curr, sizeof(struct in_addr));
 728       addr->sin_family = (unsigned short)(he->h_addrtype);
 729       addr->sin_port = htons((unsigned short)port);
 730       break;
 731
 732 #ifdef CURLRES_IPV6
 733     case AF_INET6:
 734       addr6 = (struct sockaddr_in6 *)ai->ai_addr; /* storage area for this info */
 735
 736       memcpy((char *)&(addr6->sin6_addr), curr, sizeof(struct in6_addr));
 737       addr6->sin6_family = (unsigned short)(he->h_addrtype);
 738       addr6->sin6_port = htons((unsigned short)port);
 739       break;
 740 #endif /* CURLRES_IPV6 */
 741     }
 742
 743     prevai = ai;
 744   }
 745   return firstai;
 746 }
 747
 748 #endif /* CURLRES_IPV4 || CURLRES_ARES */