contrib/bind-9.5.2/lib/lwres/getipnode.c

   1 /*
   2  * Copyright (C) 2004, 2005, 2007, 2009  Internet Systems Consortium, Inc. ("ISC")
   3  * Copyright (C) 1999-2003  Internet Software Consortium.
   4  *
   5  * Permission to use, copy, modify, and/or distribute this software for any
   6  * purpose with or without fee is hereby granted, provided that the above
   7  * copyright notice and this permission notice appear in all copies.
   8  *
   9  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
  10  * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
  11  * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
  12  * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
  13  * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
  14  * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
  15  * PERFORMANCE OF THIS SOFTWARE.
  16  */
  17
  18 /* $Id: getipnode.c,v 1.42.128.3 2009/09/01 23:46:36 tbox Exp $ */
  19
  20 /*! \file */
  21
  22 /**
  23  *    These functions perform thread safe, protocol independent
  24  *    nodename-to-address and address-to-nodename translation as defined in
  25  *    RFC2553.  This use a struct hostent which is defined in namedb.h:
  26  *
  27  * \code
  28  * struct  hostent {
  29  *         char    *h_name;        // official name of host
  30  *         char    **h_aliases;    // alias list
  31  *         int     h_addrtype;     // host address type
  32  *         int     h_length;       // length of address
  33  *         char    **h_addr_list;  // list of addresses from name server
  34  * };
  35  * #define h_addr  h_addr_list[0]  // address, for backward compatibility
  36  * \endcode
  37  *
  38  *    The members of this structure are:
  39  *
  40  * \li   h_name:
  41  *           The official (canonical) name of the host.
  42  *
  43  * \li   h_aliases:
  44  *           A NULL-terminated array of alternate names (nicknames) for the
  45  *           host.
  46  *
  47  * \li   h_addrtype:
  48  *           The type of address being returned - usually PF_INET or
  49  *           PF_INET6.
  50  *
  51  * \li   h_length:
  52  *           The length of the address in bytes.
  53  *
  54  * \li   h_addr_list:
  55  *           A NULL terminated array of network addresses for the host. Host
  56  *           addresses are returned in network byte order.
  57  *
  58  *    lwres_getipnodebyname() looks up addresses of protocol family af for
  59  *    the hostname name. The flags parameter contains ORed flag bits to
  60  *    specify the types of addresses that are searched for, and the types of
  61  *    addresses that are returned. The flag bits are:
  62  *
  63  * \li   #AI_V4MAPPED:
  64  *           This is used with an af of #AF_INET6, and causes IPv4 addresses
  65  *           to be returned as IPv4-mapped IPv6 addresses.
  66  *
  67  * \li   #AI_ALL:
  68  *           This is used with an af of #AF_INET6, and causes all known
  69  *           addresses (IPv6 and IPv4) to be returned. If #AI_V4MAPPED is
  70  *           also set, the IPv4 addresses are return as mapped IPv6
  71  *           addresses.
  72  *
  73  * \li   #AI_ADDRCONFIG:
  74  *           Only return an IPv6 or IPv4 address if here is an active
  75  *           network interface of that type. This is not currently
  76  *           implemented in the BIND 9 lightweight resolver, and the flag is
  77  *           ignored.
  78  *
  79  * \li   #AI_DEFAULT:
  80  *           This default sets the #AI_V4MAPPED and #AI_ADDRCONFIG flag bits.
  81  *
  82  *    lwres_getipnodebyaddr() performs a reverse lookup of address src which
  83  *    is len bytes long. af denotes the protocol family, typically PF_INET
  84  *    or PF_INET6.
  85  *
  86  *    lwres_freehostent() releases all the memory associated with the struct
  87  *    hostent pointer. Any memory allocated for the h_name, h_addr_list
  88  *    and h_aliases is freed, as is the memory for the hostent structure
  89  *    itself.
  90  *
  91  * \section getipnode_return Return Values
  92  *
  93  *    If an error occurs, lwres_getipnodebyname() and
  94  *    lwres_getipnodebyaddr() set *error_num to an appropriate error code
  95  *    and the function returns a NULL pointer. The error codes and their
  96  *    meanings are defined in \link netdb.h <lwres/netdb.h>\endlink:
  97  *
  98  * \li   #HOST_NOT_FOUND:
  99  *           No such host is known.
 100  *
 101  * \li   #NO_ADDRESS:
 102  *           The server recognised the request and the name but no address
 103  *           is available. Another type of request to the name server for
 104  *           the domain might return an answer.
 105  *
 106  * \li   #TRY_AGAIN:
 107  *           A temporary and possibly transient error occurred, such as a
 108  *           failure of a server to respond. The request may succeed if
 109  *           retried.
 110  *
 111  * \li   #NO_RECOVERY:
 112  *           An unexpected failure occurred, and retrying the request is
 113  *           pointless.
 114  *
 115  *    lwres_hstrerror() translates these error codes to suitable error
 116  *    messages.
 117  *
 118  * \section getipnode_see See Also
 119  *
 120  * getaddrinfo.c, gethost.c, getnameinfo.c, herror.c, RFC2553
 121  */
 122
 123 #include <config.h>
 124
 125 #include <stdio.h>
 126 #include <stdlib.h>
 127 #include <string.h>
 128 #include <errno.h>
 129
 130 #include <lwres/lwres.h>
 131 #include <lwres/net.h>
 132 #include <lwres/netdb.h>        /* XXX #include <netdb.h> */
 133
 134 #include "assert_p.h"
 135
 136 #ifndef INADDRSZ
 137 #define INADDRSZ 4
 138 #endif
 139 #ifndef IN6ADDRSZ
 140 #define IN6ADDRSZ 16
 141 #endif
 142
 143 #ifdef LWRES_PLATFORM_NEEDIN6ADDRANY
 144 LIBLWRES_EXTERNAL_DATA const struct in6_addr in6addr_any = IN6ADDR_ANY_INIT;
 145 #endif
 146
 147 #ifndef IN6_IS_ADDR_V4COMPAT
 148 static const unsigned char in6addr_compat[12] = {
 149         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
 150 };
 151 #define IN6_IS_ADDR_V4COMPAT(x) (!memcmp((x)->s6_addr, in6addr_compat, 12) && \
 152                                  ((x)->s6_addr[12] != 0 || \
 153                                   (x)->s6_addr[13] != 0 || \
 154                                   (x)->s6_addr[14] != 0 || \
 155                                    ((x)->s6_addr[15] != 0 && \
 156                                     (x)->s6_addr[15] != 1)))
 157 #endif
 158 #ifndef IN6_IS_ADDR_V4MAPPED
 159 #define IN6_IS_ADDR_V4MAPPED(x) (!memcmp((x)->s6_addr, in6addr_mapped, 12))
 160 #endif
 161
 162 static const unsigned char in6addr_mapped[12] = {
 163         0, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0xff, 0xff
 164 };
 165
 166 /***
 167  ***    Forward declarations.
 168  ***/
 169
 170 static int
 171 scan_interfaces(int *, int *);
 172
 173 static struct hostent *
 174 copyandmerge(struct hostent *, struct hostent *, int, int *);
 175
 176 static struct hostent *
 177 hostfromaddr(lwres_gnbaresponse_t *addr, int af, const void *src);
 178
 179 static struct hostent *
 180 hostfromname(lwres_gabnresponse_t *name, int af);
 181
 182 /***
 183  ***    Public functions.
 184  ***/
 185
 186 /*!
 187  *      AI_V4MAPPED + AF_INET6
 188  *      If no IPv6 address then a query for IPv4 and map returned values.
 189  *
 190  *      AI_ALL + AI_V4MAPPED + AF_INET6
 191  *      Return IPv6 and IPv4 mapped.
 192  *
 193  *      AI_ADDRCONFIG
 194  *      Only return IPv6 / IPv4 address if there is an interface of that
 195  *      type active.
 196  */
 197
 198 struct hostent *
 199 lwres_getipnodebyname(const char *name, int af, int flags, int *error_num) {
 200         int have_v4 = 1, have_v6 = 1;
 201         struct in_addr in4;
 202         struct in6_addr in6;
 203         struct hostent he, *he1 = NULL, *he2 = NULL, *he3 = NULL;
 204         int v4 = 0, v6 = 0;
 205         int tmp_err;
 206         lwres_context_t *lwrctx = NULL;
 207         lwres_gabnresponse_t *by = NULL;
 208         int n;
 209
 210         /*
 211          * If we care about active interfaces then check.
 212          */
 213         if ((flags & AI_ADDRCONFIG) != 0)
 214                 if (scan_interfaces(&have_v4, &have_v6) == -1) {
 215                         *error_num = NO_RECOVERY;
 216                         return (NULL);
 217                 }
 218
 219         /* Check for literal address. */
 220         if ((v4 = lwres_net_pton(AF_INET, name, &in4)) != 1)
 221                 v6 = lwres_net_pton(AF_INET6, name, &in6);
 222
 223         /*
 224          * Impossible combination?
 225          */
 226         if ((af == AF_INET6 && (flags & AI_V4MAPPED) == 0 && v4 == 1) ||
 227             (af == AF_INET && v6 == 1) ||
 228             (have_v4 == 0 && v4 == 1) ||
 229             (have_v6 == 0 && v6 == 1) ||
 230             (have_v4 == 0 && af == AF_INET) ||
 231             (have_v6 == 0 && af == AF_INET6 &&
 232              (((flags & AI_V4MAPPED) != 0 && have_v4) ||
 233               (flags & AI_V4MAPPED) == 0))) {
 234                 *error_num = HOST_NOT_FOUND;
 235                 return (NULL);
 236         }
 237
 238         /*
 239          * Literal address?
 240          */
 241         if (v4 == 1 || v6 == 1) {
 242                 char *addr_list[2];
 243                 char *aliases[1];
 244                 char mappedname[sizeof("::ffff:123.123.123.123")];
 245                 union {
 246                         const char *const_name;
 247                         char *deconst_name;
 248                 } u;
 249
 250                 u.const_name = name;
 251                 if (v4 == 1 && af == AF_INET6) {
 252                         strcpy(mappedname, "::ffff:");
 253                         lwres_net_ntop(AF_INET, (char *)&in4,
 254                                        mappedname + sizeof("::ffff:") - 1,
 255                                        sizeof(mappedname) - sizeof("::ffff:")
 256                                        + 1);
 257                         he.h_name = mappedname;
 258                 } else
 259                         he.h_name = u.deconst_name;
 260                 he.h_addr_list = addr_list;
 261                 he.h_addr_list[0] = (v4 == 1) ? (char *)&in4 : (char *)&in6;
 262                 he.h_addr_list[1] = NULL;
 263                 he.h_aliases = aliases;
 264                 he.h_aliases[0] = NULL;
 265                 he.h_length = (v4 == 1) ? INADDRSZ : IN6ADDRSZ;
 266                 he.h_addrtype = (v4 == 1) ? AF_INET : AF_INET6;
 267                 return (copyandmerge(&he, NULL, af, error_num));
 268         }
 269
 270         n = lwres_context_create(&lwrctx, NULL, NULL, NULL, 0);
 271         if (n != 0) {
 272                 *error_num = NO_RECOVERY;
 273                 goto cleanup;
 274         }
 275         (void) lwres_conf_parse(lwrctx, lwres_resolv_conf);
 276         tmp_err = NO_RECOVERY;
 277         if (have_v6 && af == AF_INET6) {
 278
 279                 n = lwres_getaddrsbyname(lwrctx, name, LWRES_ADDRTYPE_V6, &by);
 280                 if (n == 0) {
 281                         he1 = hostfromname(by, AF_INET6);
 282                         lwres_gabnresponse_free(lwrctx, &by);
 283                         if (he1 == NULL) {
 284                                 *error_num = NO_RECOVERY;
 285                                 goto cleanup;
 286                         }
 287                 } else {
 288                         tmp_err = HOST_NOT_FOUND;
 289                 }
 290         }
 291
 292         if (have_v4 &&
 293             ((af == AF_INET) ||
 294              (af == AF_INET6 && (flags & AI_V4MAPPED) != 0 &&
 295               (he1 == NULL || (flags & AI_ALL) != 0)))) {
 296                 n = lwres_getaddrsbyname(lwrctx, name, LWRES_ADDRTYPE_V4, &by);
 297                 if (n == 0) {
 298                         he2 = hostfromname(by, AF_INET);
 299                         lwres_gabnresponse_free(lwrctx, &by);
 300                         if (he2 == NULL) {
 301                                 *error_num = NO_RECOVERY;
 302                                 goto cleanup;
 303                         }
 304                 } else if (he1 == NULL) {
 305                         if (n == LWRES_R_NOTFOUND)
 306                                 *error_num = HOST_NOT_FOUND;
 307                         else
 308                                 *error_num = NO_RECOVERY;
 309                         goto cleanup;
 310                 }
 311         } else
 312                 *error_num = tmp_err;
 313
 314         he3 = copyandmerge(he1, he2, af, error_num);
 315
 316  cleanup:
 317         if (he1 != NULL)
 318                 lwres_freehostent(he1);
 319         if (he2 != NULL)
 320                 lwres_freehostent(he2);
 321         if (lwrctx != NULL) {
 322                 lwres_conf_clear(lwrctx);
 323                 lwres_context_destroy(&lwrctx);
 324         }
 325         return (he3);
 326 }
 327
 328 /*% performs a reverse lookup of address src which is len bytes long. af denotes the protocol family, typically #PF_INET or PF_INET6. */
 329 struct hostent *
 330 lwres_getipnodebyaddr(const void *src, size_t len, int af, int *error_num) {
 331         struct hostent *he1, *he2;
 332         lwres_context_t *lwrctx = NULL;
 333         lwres_gnbaresponse_t *by = NULL;
 334         lwres_result_t n;
 335         union {
 336                 const void *konst;
 337                 struct in6_addr *in6;
 338         } u;
 339
 340         /*
 341          * Sanity checks.
 342          */
 343         if (src == NULL) {
 344                 *error_num = NO_RECOVERY;
 345                 return (NULL);
 346         }
 347
 348         switch (af) {
 349         case AF_INET:
 350                 if (len != (unsigned int)INADDRSZ) {
 351                         *error_num = NO_RECOVERY;
 352                         return (NULL);
 353                 }
 354                 break;
 355         case AF_INET6:
 356                 if (len != (unsigned int)IN6ADDRSZ) {
 357                         *error_num = NO_RECOVERY;
 358                         return (NULL);
 359                 }
 360                 break;
 361         default:
 362                 *error_num = NO_RECOVERY;
 363                 return (NULL);
 364         }
 365
 366         /*
 367          * The de-"const"-ing game is done because at least one
 368          * vendor's system (RedHat 6.0) defines the IN6_IS_ADDR_*
 369          * macros in such a way that they discard the const with
 370          * internal casting, and gcc ends up complaining.  Rather
 371          * than replacing their own (possibly optimized) definitions
 372          * with our own, cleanly discarding the const is the easiest
 373          * thing to do.
 374          */
 375         u.konst = src;
 376
 377         /*
 378          * Look up IPv4 and IPv4 mapped/compatible addresses.
 379          */
 380         if ((af == AF_INET6 && IN6_IS_ADDR_V4COMPAT(u.in6)) ||
 381             (af == AF_INET6 && IN6_IS_ADDR_V4MAPPED(u.in6)) ||
 382             (af == AF_INET)) {
 383                 const unsigned char *cp = src;
 384
 385                 if (af == AF_INET6)
 386                         cp += 12;
 387                 n = lwres_context_create(&lwrctx, NULL, NULL, NULL, 0);
 388                 if (n == LWRES_R_SUCCESS)
 389                         (void) lwres_conf_parse(lwrctx, lwres_resolv_conf);
 390                 if (n == LWRES_R_SUCCESS)
 391                         n = lwres_getnamebyaddr(lwrctx, LWRES_ADDRTYPE_V4,
 392                                                 INADDRSZ, cp, &by);
 393                 if (n != LWRES_R_SUCCESS) {
 394                         lwres_conf_clear(lwrctx);
 395                         lwres_context_destroy(&lwrctx);
 396                         if (n == LWRES_R_NOTFOUND)
 397                                 *error_num = HOST_NOT_FOUND;
 398                         else
 399                                 *error_num = NO_RECOVERY;
 400                         return (NULL);
 401                 }
 402                 he1 = hostfromaddr(by, AF_INET, cp);
 403                 lwres_gnbaresponse_free(lwrctx, &by);
 404                 lwres_conf_clear(lwrctx);
 405                 lwres_context_destroy(&lwrctx);
 406                 if (af != AF_INET6)
 407                         return (he1);
 408
 409                 /*
 410                  * Convert from AF_INET to AF_INET6.
 411                  */
 412                 he2 = copyandmerge(he1, NULL, af, error_num);
 413                 lwres_freehostent(he1);
 414                 if (he2 == NULL)
 415                         return (NULL);
 416                 /*
 417                  * Restore original address.
 418                  */
 419                 memcpy(he2->h_addr, src, len);
 420                 return (he2);
 421         }
 422
 423         /*
 424          * Lookup IPv6 address.
 425          */
 426         if (memcmp(src, &in6addr_any, IN6ADDRSZ) == 0) {
 427                 *error_num = HOST_NOT_FOUND;
 428                 return (NULL);
 429         }
 430
 431         n = lwres_context_create(&lwrctx, NULL, NULL, NULL, 0);
 432         if (n == LWRES_R_SUCCESS)
 433                 (void) lwres_conf_parse(lwrctx, lwres_resolv_conf);
 434         if (n == LWRES_R_SUCCESS)
 435                 n = lwres_getnamebyaddr(lwrctx, LWRES_ADDRTYPE_V6, IN6ADDRSZ,
 436                                         src, &by);
 437         if (n != 0) {
 438                 lwres_conf_clear(lwrctx);
 439                 lwres_context_destroy(&lwrctx);
 440                 *error_num = HOST_NOT_FOUND;
 441                 return (NULL);
 442         }
 443         he1 = hostfromaddr(by, AF_INET6, src);
 444         lwres_gnbaresponse_free(lwrctx, &by);
 445         if (he1 == NULL)
 446                 *error_num = NO_RECOVERY;
 447         lwres_conf_clear(lwrctx);
 448         lwres_context_destroy(&lwrctx);
 449         return (he1);
 450 }
 451
 452 /*% releases all the memory associated with the struct hostent pointer */
 453 void
 454 lwres_freehostent(struct hostent *he) {
 455         char **cpp;
 456         int names = 1;
 457         int addresses = 1;
 458
 459         free(he->h_name);
 460
 461         cpp = he->h_addr_list;
 462         while (*cpp != NULL) {
 463                 free(*cpp);
 464                 *cpp = NULL;
 465                 cpp++;
 466                 addresses++;
 467         }
 468
 469         cpp = he->h_aliases;
 470         while (*cpp != NULL) {
 471                 free(*cpp);
 472                 cpp++;
 473                 names++;
 474         }
 475
 476         free(he->h_aliases);
 477         free(he->h_addr_list);
 478         free(he);
 479 }
 480
 481 /*
 482  * Private
 483  */
 484
 485 /*
 486  * Scan the interface table and set have_v4 and have_v6 depending
 487  * upon whether there are IPv4 and IPv6 interface addresses.
 488  *
 489  * Returns:
 490  *      0 on success
 491  *      -1 on failure.
 492  */
 493
 494 #if defined(SIOCGLIFCONF) && defined(SIOCGLIFADDR) && \
 495     !defined(IRIX_EMUL_IOCTL_SIOCGIFCONF)
 496
 497 #ifdef __hpux
 498 #define lifc_len iflc_len
 499 #define lifc_buf iflc_buf
 500 #define lifc_req iflc_req
 501 #define LIFCONF if_laddrconf
 502 #else
 503 #define ISC_HAVE_LIFC_FAMILY 1
 504 #define ISC_HAVE_LIFC_FLAGS 1
 505 #define LIFCONF lifconf
 506 #endif
 507
 508 #ifdef __hpux
 509 #define lifr_addr iflr_addr
 510 #define lifr_name iflr_name
 511 #define lifr_dstaddr iflr_dstaddr
 512 #define lifr_flags iflr_flags
 513 #define ss_family sa_family
 514 #define LIFREQ if_laddrreq
 515 #else
 516 #define LIFREQ lifreq
 517 #endif
 518
 519 static int
 520 scan_interfaces6(int *have_v4, int *have_v6) {
 521         struct LIFCONF lifc;
 522         struct LIFREQ lifreq;
 523         struct in_addr in4;
 524         struct in6_addr in6;
 525         char *buf = NULL, *cp, *cplim;
 526         static unsigned int bufsiz = 4095;
 527         int s, cpsize, n;
 528
 529         /*
 530          * Set to zero.  Used as loop terminators below.
 531          */
 532         *have_v4 = *have_v6 = 0;
 533
 534         /*
 535          * Get interface list from system.
 536          */
 537         if ((s = socket(AF_INET6, SOCK_DGRAM, 0)) == -1)
 538                 goto err_ret;
 539
 540         /*
 541          * Grow buffer until large enough to contain all interface
 542          * descriptions.
 543          */
 544         for (;;) {
 545                 buf = malloc(bufsiz);
 546                 if (buf == NULL)
 547                         goto err_ret;
 548 #ifdef ISC_HAVE_LIFC_FAMILY
 549                 lifc.lifc_family = AF_UNSPEC;   /* request all families */
 550 #endif
 551 #ifdef ISC_HAVE_LIFC_FLAGS
 552                 lifc.lifc_flags = 0;
 553 #endif
 554                 lifc.lifc_len = bufsiz;
 555                 lifc.lifc_buf = buf;
 556                 if ((n = ioctl(s, SIOCGLIFCONF, (char *)&lifc)) != -1) {
 557                         /*
 558                          * Some OS's just return what will fit rather
 559                          * than set EINVAL if the buffer is too small
 560                          * to fit all the interfaces in.  If
 561                          * lifc.lifc_len is too near to the end of the
 562                          * buffer we will grow it just in case and
 563                          * retry.
 564                          */
 565                         if (lifc.lifc_len + 2 * sizeof(lifreq) < bufsiz)
 566                                 break;
 567                 }
 568                 if ((n == -1) && errno != EINVAL)
 569                         goto err_ret;
 570
 571                 if (bufsiz > 1000000)
 572                         goto err_ret;
 573
 574                 free(buf);
 575                 bufsiz += 4096;
 576         }
 577
 578         /*
 579          * Parse system's interface list.
 580          */
 581         cplim = buf + lifc.lifc_len;    /* skip over if's with big ifr_addr's */
 582         for (cp = buf;
 583              (*have_v4 == 0 || *have_v6 == 0) && cp < cplim;
 584              cp += cpsize) {
 585                 memcpy(&lifreq, cp, sizeof(lifreq));
 586 #ifdef LWRES_PLATFORM_HAVESALEN
 587 #ifdef FIX_ZERO_SA_LEN
 588                 if (lifreq.lifr_addr.sa_len == 0)
 589                         lifreq.lifr_addr.sa_len = 16;
 590 #endif
 591 #ifdef HAVE_MINIMUM_IFREQ
 592                 cpsize = sizeof(lifreq);
 593                 if (lifreq.lifr_addr.sa_len > sizeof(struct sockaddr))
 594                         cpsize += (int)lifreq.lifr_addr.sa_len -
 595                                 (int)(sizeof(struct sockaddr));
 596 #else
 597                 cpsize = sizeof(lifreq.lifr_name) + lifreq.lifr_addr.sa_len;
 598 #endif /* HAVE_MINIMUM_IFREQ */
 599 #elif defined SIOCGIFCONF_ADDR
 600                 cpsize = sizeof(lifreq);
 601 #else
 602                 cpsize = sizeof(lifreq.lifr_name);
 603                 /* XXX maybe this should be a hard error? */
 604                 if (ioctl(s, SIOCGLIFADDR, (char *)&lifreq) < 0)
 605                         continue;
 606 #endif
 607                 switch (lifreq.lifr_addr.ss_family) {
 608                 case AF_INET:
 609                         if (*have_v4 == 0) {
 610                                 memcpy(&in4,
 611                                        &((struct sockaddr_in *)
 612                                        &lifreq.lifr_addr)->sin_addr,
 613                                        sizeof(in4));
 614                                 if (in4.s_addr == INADDR_ANY)
 615                                         break;
 616                                 n = ioctl(s, SIOCGLIFFLAGS, (char *)&lifreq);
 617                                 if (n < 0)
 618                                         break;
 619                                 if ((lifreq.lifr_flags & IFF_UP) == 0)
 620                                         break;
 621                                 *have_v4 = 1;
 622                         }
 623                         break;
 624                 case AF_INET6:
 625                         if (*have_v6 == 0) {
 626                                 memcpy(&in6,
 627                                        &((struct sockaddr_in6 *)
 628                                        &lifreq.lifr_addr)->sin6_addr,
 629                                        sizeof(in6));
 630                                 if (memcmp(&in6, &in6addr_any,
 631                                            sizeof(in6)) == 0)
 632                                         break;
 633                                 n = ioctl(s, SIOCGLIFFLAGS, (char *)&lifreq);
 634                                 if (n < 0)
 635                                         break;
 636                                 if ((lifreq.lifr_flags & IFF_UP) == 0)
 637                                         break;
 638                                 *have_v6 = 1;
 639                         }
 640                         break;
 641                 }
 642         }
 643         if (buf != NULL)
 644                 free(buf);
 645         close(s);
 646         return (0);
 647  err_ret:
 648         if (buf != NULL)
 649                 free(buf);
 650         if (s != -1)
 651                 close(s);
 652         return (-1);
 653 }
 654 #endif
 655
 656 static int
 657 scan_interfaces(int *have_v4, int *have_v6) {
 658 #if !defined(SIOCGIFCONF) || !defined(SIOCGIFADDR)
 659         *have_v4 = *have_v6 = 1;
 660         return (0);
 661 #else
 662         struct ifconf ifc;
 663         union {
 664                 char _pad[256];         /* leave space for IPv6 addresses */
 665                 struct ifreq ifreq;
 666         } u;
 667         struct in_addr in4;
 668         struct in6_addr in6;
 669         char *buf = NULL, *cp, *cplim;
 670         static unsigned int bufsiz = 4095;
 671         int s, n;
 672         size_t cpsize;
 673
 674 #ifdef WIN32
 675         InitSockets();
 676 #endif
 677 #if defined(SIOCGLIFCONF) && defined(SIOCGLIFADDR) && \
 678     !defined(IRIX_EMUL_IOCTL_SIOCGIFCONF)
 679         /*
 680          * Try to scan the interfaces using IPv6 ioctls().
 681          */
 682         if (!scan_interfaces6(have_v4, have_v6)) {
 683 #ifdef WIN32
 684                 DestroySockets();
 685 #endif
 686                 return (0);
 687         }
 688 #endif
 689
 690         /*
 691          * Set to zero.  Used as loop terminators below.
 692          */
 693         *have_v4 = *have_v6 = 0;
 694
 695         /*
 696          * Get interface list from system.
 697          */
 698         if ((s = socket(AF_INET, SOCK_DGRAM, 0)) == -1)
 699                 goto err_ret;
 700
 701         /*
 702          * Grow buffer until large enough to contain all interface
 703          * descriptions.
 704          */
 705         for (;;) {
 706                 buf = malloc(bufsiz);
 707                 if (buf == NULL)
 708                         goto err_ret;
 709                 ifc.ifc_len = bufsiz;
 710                 ifc.ifc_buf = buf;
 711 #ifdef IRIX_EMUL_IOCTL_SIOCGIFCONF
 712                 /*
 713                  * This is a fix for IRIX OS in which the call to ioctl with
 714                  * the flag SIOCGIFCONF may not return an entry for all the
 715                  * interfaces like most flavors of Unix.
 716                  */
 717                 if (emul_ioctl(&ifc) >= 0)
 718                         break;
 719 #else
 720                 if ((n = ioctl(s, SIOCGIFCONF, (char *)&ifc)) != -1) {
 721                         /*
 722                          * Some OS's just return what will fit rather
 723                          * than set EINVAL if the buffer is too small
 724                          * to fit all the interfaces in.  If
 725                          * ifc.ifc_len is too near to the end of the
 726                          * buffer we will grow it just in case and
 727                          * retry.
 728                          */
 729                         if (ifc.ifc_len + 2 * sizeof(u.ifreq) < bufsiz)
 730                                 break;
 731                 }
 732 #endif
 733                 if ((n == -1) && errno != EINVAL)
 734                         goto err_ret;
 735
 736                 if (bufsiz > 1000000)
 737                         goto err_ret;
 738
 739                 free(buf);
 740                 bufsiz += 4096;
 741         }
 742
 743         /*
 744          * Parse system's interface list.
 745          */
 746         cplim = buf + ifc.ifc_len;    /* skip over if's with big ifr_addr's */
 747         for (cp = buf;
 748              (*have_v4 == 0 || *have_v6 == 0) && cp < cplim;
 749              cp += cpsize) {
 750                 memcpy(&u.ifreq, cp, sizeof(u.ifreq));
 751 #ifdef LWRES_PLATFORM_HAVESALEN
 752 #ifdef FIX_ZERO_SA_LEN
 753                 if (u.ifreq.ifr_addr.sa_len == 0)
 754                         u.ifreq.ifr_addr.sa_len = 16;
 755 #endif
 756 #ifdef HAVE_MINIMUM_IFREQ
 757                 cpsize = sizeof(u.ifreq);
 758                 if (u.ifreq.ifr_addr.sa_len > sizeof(struct sockaddr))
 759                         cpsize += (int)u.ifreq.ifr_addr.sa_len -
 760                                 (int)(sizeof(struct sockaddr));
 761 #else
 762                 cpsize = sizeof(u.ifreq.ifr_name) + u.ifreq.ifr_addr.sa_len;
 763 #endif /* HAVE_MINIMUM_IFREQ */
 764                 if (cpsize > sizeof(u.ifreq) && cpsize <= sizeof(u))
 765                         memcpy(&u.ifreq, cp, cpsize);
 766 #elif defined SIOCGIFCONF_ADDR
 767                 cpsize = sizeof(u.ifreq);
 768 #else
 769                 cpsize = sizeof(u.ifreq.ifr_name);
 770                 /* XXX maybe this should be a hard error? */
 771                 if (ioctl(s, SIOCGIFADDR, (char *)&u.ifreq) < 0)
 772                         continue;
 773 #endif
 774                 switch (u.ifreq.ifr_addr.sa_family) {
 775                 case AF_INET:
 776                         if (*have_v4 == 0) {
 777                                 memcpy(&in4,
 778                                        &((struct sockaddr_in *)
 779                                        &u.ifreq.ifr_addr)->sin_addr,
 780                                        sizeof(in4));
 781                                 if (in4.s_addr == INADDR_ANY)
 782                                         break;
 783                                 n = ioctl(s, SIOCGIFFLAGS, (char *)&u.ifreq);
 784                                 if (n < 0)
 785                                         break;
 786                                 if ((u.ifreq.ifr_flags & IFF_UP) == 0)
 787                                         break;
 788                                 *have_v4 = 1;
 789                         }
 790                         break;
 791                 case AF_INET6:
 792                         if (*have_v6 == 0) {
 793                                 memcpy(&in6,
 794                                        &((struct sockaddr_in6 *)
 795                                        &u.ifreq.ifr_addr)->sin6_addr,
 796                                        sizeof(in6));
 797                                 if (memcmp(&in6, &in6addr_any,
 798                                            sizeof(in6)) == 0)
 799                                         break;
 800                                 n = ioctl(s, SIOCGIFFLAGS, (char *)&u.ifreq);
 801                                 if (n < 0)
 802                                         break;
 803                                 if ((u.ifreq.ifr_flags & IFF_UP) == 0)
 804                                         break;
 805                                 *have_v6 = 1;
 806                         }
 807                         break;
 808                 }
 809         }
 810         if (buf != NULL)
 811                 free(buf);
 812 #ifdef WIN32
 813         DestroySockets();
 814 #endif
 815         close(s);
 816         return (0);
 817
 818  err_ret:
 819         if (buf != NULL)
 820                 free(buf);
 821         if (s != -1)
 822                 close(s);
 823 #ifdef WIN32
 824         DestroySockets();
 825 #endif
 826         return (-1);
 827 #endif
 828 }
 829
 830 static struct hostent *
 831 copyandmerge(struct hostent *he1, struct hostent *he2, int af, int *error_num)
 832 {
 833         struct hostent *he = NULL;
 834         int addresses = 1;      /* NULL terminator */
 835         int names = 1;          /* NULL terminator */
 836         int len = 0;
 837         char **cpp, **npp;
 838
 839         /*
 840          * Work out array sizes.
 841          */
 842         if (he1 != NULL) {
 843                 cpp = he1->h_addr_list;
 844                 while (*cpp != NULL) {
 845                         addresses++;
 846                         cpp++;
 847                 }
 848                 cpp = he1->h_aliases;
 849                 while (*cpp != NULL) {
 850                         names++;
 851                         cpp++;
 852                 }
 853         }
 854
 855         if (he2 != NULL) {
 856                 cpp = he2->h_addr_list;
 857                 while (*cpp != NULL) {
 858                         addresses++;
 859                         cpp++;
 860                 }
 861                 if (he1 == NULL) {
 862                         cpp = he2->h_aliases;
 863                         while (*cpp != NULL) {
 864                                 names++;
 865                                 cpp++;
 866                         }
 867                 }
 868         }
 869
 870         if (addresses == 1) {
 871                 *error_num = NO_ADDRESS;
 872                 return (NULL);
 873         }
 874
 875         he = malloc(sizeof(*he));
 876         if (he == NULL)
 877                 goto no_recovery;
 878
 879         he->h_addr_list = malloc(sizeof(char *) * (addresses));
 880         if (he->h_addr_list == NULL)
 881                 goto cleanup0;
 882         memset(he->h_addr_list, 0, sizeof(char *) * (addresses));
 883
 884         /*
 885          * Copy addresses.
 886          */
 887         npp = he->h_addr_list;
 888         if (he1 != NULL) {
 889                 cpp = he1->h_addr_list;
 890                 while (*cpp != NULL) {
 891                         *npp = malloc((af == AF_INET) ? INADDRSZ : IN6ADDRSZ);
 892                         if (*npp == NULL)
 893                                 goto cleanup1;
 894                         /*
 895                          * Convert to mapped if required.
 896                          */
 897                         if (af == AF_INET6 && he1->h_addrtype == AF_INET) {
 898                                 memcpy(*npp, in6addr_mapped,
 899                                        sizeof(in6addr_mapped));
 900                                 memcpy(*npp + sizeof(in6addr_mapped), *cpp,
 901                                        INADDRSZ);
 902                         } else {
 903                                 memcpy(*npp, *cpp,
 904                                        (af == AF_INET) ? INADDRSZ : IN6ADDRSZ);
 905                         }
 906                         cpp++;
 907                         npp++;
 908                 }
 909         }
 910
 911         if (he2 != NULL) {
 912                 cpp = he2->h_addr_list;
 913                 while (*cpp != NULL) {
 914                         *npp = malloc((af == AF_INET) ? INADDRSZ : IN6ADDRSZ);
 915                         if (*npp == NULL)
 916                                 goto cleanup1;
 917                         /*
 918                          * Convert to mapped if required.
 919                          */
 920                         if (af == AF_INET6 && he2->h_addrtype == AF_INET) {
 921                                 memcpy(*npp, in6addr_mapped,
 922                                        sizeof(in6addr_mapped));
 923                                 memcpy(*npp + sizeof(in6addr_mapped), *cpp,
 924                                        INADDRSZ);
 925                         } else {
 926                                 memcpy(*npp, *cpp,
 927                                        (af == AF_INET) ? INADDRSZ : IN6ADDRSZ);
 928                         }
 929                         cpp++;
 930                         npp++;
 931                 }
 932         }
 933
 934         he->h_aliases = malloc(sizeof(char *) * (names));
 935         if (he->h_aliases == NULL)
 936                 goto cleanup1;
 937         memset(he->h_aliases, 0, sizeof(char *) * (names));
 938
 939         /*
 940          * Copy aliases.
 941          */
 942         npp = he->h_aliases;
 943         cpp = (he1 != NULL) ? he1->h_aliases : he2->h_aliases;
 944         while (*cpp != NULL) {
 945                 len = strlen (*cpp) + 1;
 946                 *npp = malloc(len);
 947                 if (*npp == NULL)
 948                         goto cleanup2;
 949                 strcpy(*npp, *cpp);
 950                 npp++;
 951                 cpp++;
 952         }
 953
 954         /*
 955          * Copy hostname.
 956          */
 957         he->h_name = malloc(strlen((he1 != NULL) ?
 958                             he1->h_name : he2->h_name) + 1);
 959         if (he->h_name == NULL)
 960                 goto cleanup2;
 961         strcpy(he->h_name, (he1 != NULL) ? he1->h_name : he2->h_name);
 962
 963         /*
 964          * Set address type and length.
 965          */
 966         he->h_addrtype = af;
 967         he->h_length = (af == AF_INET) ? INADDRSZ : IN6ADDRSZ;
 968         return (he);
 969
 970  cleanup2:
 971         cpp = he->h_aliases;
 972         while (*cpp != NULL) {
 973                 free(*cpp);
 974                 cpp++;
 975         }
 976         free(he->h_aliases);
 977
 978  cleanup1:
 979         cpp = he->h_addr_list;
 980         while (*cpp != NULL) {
 981                 free(*cpp);
 982                 *cpp = NULL;
 983                 cpp++;
 984         }
 985         free(he->h_addr_list);
 986
 987  cleanup0:
 988         free(he);
 989
 990  no_recovery:
 991         *error_num = NO_RECOVERY;
 992         return (NULL);
 993 }
 994
 995 static struct hostent *
 996 hostfromaddr(lwres_gnbaresponse_t *addr, int af, const void *src) {
 997         struct hostent *he;
 998         int i;
 999
1000         he = malloc(sizeof(*he));
1001         if (he == NULL)
1002                 goto cleanup;
1003         memset(he, 0, sizeof(*he));
1004
1005         /*
1006          * Set family and length.
1007          */
1008         he->h_addrtype = af;
1009         switch (af) {
1010         case AF_INET:
1011                 he->h_length = INADDRSZ;
1012                 break;
1013         case AF_INET6:
1014                 he->h_length = IN6ADDRSZ;
1015                 break;
1016         default:
1017                 INSIST(0);
1018         }
1019
1020         /*
1021          * Copy name.
1022          */
1023         he->h_name = strdup(addr->realname);
1024         if (he->h_name == NULL)
1025                 goto cleanup;
1026
1027         /*
1028          * Copy aliases.
1029          */
1030         he->h_aliases = malloc(sizeof(char *) * (addr->naliases + 1));
1031         if (he->h_aliases == NULL)
1032                 goto cleanup;
1033         for (i = 0; i < addr->naliases; i++) {
1034                 he->h_aliases[i] = strdup(addr->aliases[i]);
1035                 if (he->h_aliases[i] == NULL)
1036                         goto cleanup;
1037         }
1038         he->h_aliases[i] = NULL;
1039
1040         /*
1041          * Copy address.
1042          */
1043         he->h_addr_list = malloc(sizeof(char *) * 2);
1044         if (he->h_addr_list == NULL)
1045                 goto cleanup;
1046         he->h_addr_list[0] = malloc(he->h_length);
1047         if (he->h_addr_list[0] == NULL)
1048                 goto cleanup;
1049         memcpy(he->h_addr_list[0], src, he->h_length);
1050         he->h_addr_list[1] = NULL;
1051         return (he);
1052
1053  cleanup:
1054         if (he != NULL && he->h_addr_list != NULL) {
1055                 for (i = 0; he->h_addr_list[i] != NULL; i++)
1056                         free(he->h_addr_list[i]);
1057                 free(he->h_addr_list);
1058         }
1059         if (he != NULL && he->h_aliases != NULL) {
1060                 for (i = 0; he->h_aliases[i] != NULL; i++)
1061                         free(he->h_aliases[i]);
1062                 free(he->h_aliases);
1063         }
1064         if (he != NULL && he->h_name != NULL)
1065                 free(he->h_name);
1066         if (he != NULL)
1067                 free(he);
1068         return (NULL);
1069 }
1070
1071 static struct hostent *
1072 hostfromname(lwres_gabnresponse_t *name, int af) {
1073         struct hostent *he;
1074         int i;
1075         lwres_addr_t *addr;
1076
1077         he = malloc(sizeof(*he));
1078         if (he == NULL)
1079                 goto cleanup;
1080         memset(he, 0, sizeof(*he));
1081
1082         /*
1083          * Set family and length.
1084          */
1085         he->h_addrtype = af;
1086         switch (af) {
1087         case AF_INET:
1088                 he->h_length = INADDRSZ;
1089                 break;
1090         case AF_INET6:
1091                 he->h_length = IN6ADDRSZ;
1092                 break;
1093         default:
1094                 INSIST(0);
1095         }
1096
1097         /*
1098          * Copy name.
1099          */
1100         he->h_name = strdup(name->realname);
1101         if (he->h_name == NULL)
1102                 goto cleanup;
1103
1104         /*
1105          * Copy aliases.
1106          */
1107         he->h_aliases = malloc(sizeof(char *) * (name->naliases + 1));
1108         for (i = 0; i < name->naliases; i++) {
1109                 he->h_aliases[i] = strdup(name->aliases[i]);
1110                 if (he->h_aliases[i] == NULL)
1111                         goto cleanup;
1112         }
1113         he->h_aliases[i] = NULL;
1114
1115         /*
1116          * Copy addresses.
1117          */
1118         he->h_addr_list = malloc(sizeof(char *) * (name->naddrs + 1));
1119         addr = LWRES_LIST_HEAD(name->addrs);
1120         i = 0;
1121         while (addr != NULL) {
1122                 he->h_addr_list[i] = malloc(he->h_length);
1123                 if (he->h_addr_list[i] == NULL)
1124                         goto cleanup;
1125                 memcpy(he->h_addr_list[i], addr->address, he->h_length);
1126                 addr = LWRES_LIST_NEXT(addr, link);
1127                 i++;
1128         }
1129         he->h_addr_list[i] = NULL;
1130         return (he);
1131
1132  cleanup:
1133         if (he != NULL && he->h_addr_list != NULL) {
1134                 for (i = 0; he->h_addr_list[i] != NULL; i++)
1135                         free(he->h_addr_list[i]);
1136                 free(he->h_addr_list);
1137         }
1138         if (he != NULL && he->h_aliases != NULL) {
1139                 for (i = 0; he->h_aliases[i] != NULL; i++)
1140                         free(he->h_aliases[i]);
1141                 free(he->h_aliases);
1142         }
1143         if (he != NULL && he->h_name != NULL)
1144                 free(he->h_name);
1145         if (he != NULL)
1146                 free(he);
1147         return (NULL);
1148 }