contrib/bind9/lib/irs/getaddrinfo.c

   1 /*
   2  * Copyright (C) 2009  Internet Systems Consortium, Inc. ("ISC")
   3  *
   4  * Permission to use, copy, modify, and/or distribute this software for any
   5  * purpose with or without fee is hereby granted, provided that the above
   6  * copyright notice and this permission notice appear in all copies.
   7  *
   8  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
   9  * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
  10  * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
  11  * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
  12  * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
  13  * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
  14  * PERFORMANCE OF THIS SOFTWARE.
  15  */
  16
  17 /* $Id: getaddrinfo.c,v 1.3 2009/09/02 23:48:02 tbox Exp $ */
  18
  19 /*! \file */
  20
  21 /**
  22  *    getaddrinfo() is used to get a list of IP addresses and port
  23  *    numbers for host hostname and service servname as defined in RFC3493.
  24  *    hostname and servname are pointers to null-terminated strings
  25  *    or NULL. hostname is either a host name or a numeric host address
  26  *    string: a dotted decimal IPv4 address or an IPv6 address. servname is
  27  *    either a decimal port number or a service name as listed in
  28  *    /etc/services.
  29  *
  30  *    If the operating system does not provide a struct addrinfo, the
  31  *    following structure is used:
  32  *
  33  * \code
  34  * struct  addrinfo {
  35  *         int             ai_flags;       // AI_PASSIVE, AI_CANONNAME
  36  *         int             ai_family;      // PF_xxx
  37  *         int             ai_socktype;    // SOCK_xxx
  38  *         int             ai_protocol;    // 0 or IPPROTO_xxx for IPv4 and IPv6
  39  *         size_t          ai_addrlen;     // length of ai_addr
  40  *         char            *ai_canonname;  // canonical name for hostname
  41  *         struct sockaddr *ai_addr;       // binary address
  42  *         struct addrinfo *ai_next;       // next structure in linked list
  43  * };
  44  * \endcode
  45  *
  46  *
  47  *    hints is an optional pointer to a struct addrinfo. This structure can
  48  *    be used to provide hints concerning the type of socket that the caller
  49  *    supports or wishes to use. The caller can supply the following
  50  *    structure elements in *hints:
  51  *
  52  * <ul>
  53  *    <li>ai_family:
  54  *           The protocol family that should be used. When ai_family is set
  55  *           to PF_UNSPEC, it means the caller will accept any protocol
  56  *           family supported by the operating system.</li>
  57  *
  58  *    <li>ai_socktype:
  59  *           denotes the type of socket -- SOCK_STREAM, SOCK_DGRAM or
  60  *           SOCK_RAW -- that is wanted. When ai_socktype is zero the caller
  61  *           will accept any socket type.</li>
  62  *
  63  *    <li>ai_protocol:
  64  *           indicates which transport protocol is wanted: IPPROTO_UDP or
  65  *           IPPROTO_TCP. If ai_protocol is zero the caller will accept any
  66  *           protocol.</li>
  67  *
  68  *    <li>ai_flags:
  69  *           Flag bits. If the AI_CANONNAME bit is set, a successful call to
  70  *           getaddrinfo() will return a null-terminated string
  71  *           containing the canonical name of the specified hostname in
  72  *           ai_canonname of the first addrinfo structure returned. Setting
  73  *           the AI_PASSIVE bit indicates that the returned socket address
  74  *           structure is intended for used in a call to bind(2). In this
  75  *           case, if the hostname argument is a NULL pointer, then the IP
  76  *           address portion of the socket address structure will be set to
  77  *           INADDR_ANY for an IPv4 address or IN6ADDR_ANY_INIT for an IPv6
  78  *           address.<br /><br />
  79  *
  80  *           When ai_flags does not set the AI_PASSIVE bit, the returned
  81  *           socket address structure will be ready for use in a call to
  82  *           connect(2) for a connection-oriented protocol or connect(2),
  83  *           sendto(2), or sendmsg(2) if a connectionless protocol was
  84  *           chosen. The IP address portion of the socket address structure
  85  *           will be set to the loopback address if hostname is a NULL
  86  *           pointer and AI_PASSIVE is not set in ai_flags.<br /><br />
  87  *
  88  *           If ai_flags is set to AI_NUMERICHOST it indicates that hostname
  89  *           should be treated as a numeric string defining an IPv4 or IPv6
  90  *           address and no name resolution should be attempted.
  91  * </li></ul>
  92  *
  93  *    All other elements of the struct addrinfo passed via hints must be
  94  *    zero.
  95  *
  96  *    A hints of NULL is treated as if the caller provided a struct addrinfo
  97  *    initialized to zero with ai_familyset to PF_UNSPEC.
  98  *
  99  *    After a successful call to getaddrinfo(), *res is a pointer to a
 100  *    linked list of one or more addrinfo structures. Each struct addrinfo
 101  *    in this list cn be processed by following the ai_next pointer, until a
 102  *    NULL pointer is encountered. The three members ai_family, ai_socktype,
 103  *    and ai_protocol in each returned addrinfo structure contain the
 104  *    corresponding arguments for a call to socket(2). For each addrinfo
 105  *    structure in the list, the ai_addr member points to a filled-in socket
 106  *    address structure of length ai_addrlen.
 107  *
 108  *    All of the information returned by getaddrinfo() is dynamically
 109  *    allocated: the addrinfo structures, and the socket address structures
 110  *    and canonical host name strings pointed to by the addrinfostructures.
 111  *    Memory allocated for the dynamically allocated structures created by a
 112  *    successful call to getaddrinfo() is released by freeaddrinfo().
 113  *    ai is a pointer to a struct addrinfo created by a call to getaddrinfo().
 114  *
 115  * \section irsreturn RETURN VALUES
 116  *
 117  *    getaddrinfo() returns zero on success or one of the error codes
 118  *    listed in gai_strerror() if an error occurs. If both hostname and
 119  *    servname are NULL getaddrinfo() returns #EAI_NONAME.
 120  *
 121  * \section irssee SEE ALSO
 122  *
 123  *    getaddrinfo(), freeaddrinfo(),
 124  *    gai_strerror(), RFC3493, getservbyname(3), connect(2),
 125  *    sendto(2), sendmsg(2), socket(2).
 126  */
 127
 128 #include <config.h>
 129
 130 #include <stdlib.h>
 131 #include <string.h>
 132 #include <errno.h>
 133
 134 #include <isc/app.h>
 135 #include <isc/buffer.h>
 136 #include <isc/lib.h>
 137 #include <isc/mem.h>
 138 #include <isc/sockaddr.h>
 139 #include <isc/util.h>
 140
 141 #include <dns/client.h>
 142 #include <dns/fixedname.h>
 143 #include <dns/name.h>
 144 #include <dns/rdata.h>
 145 #include <dns/rdataset.h>
 146 #include <dns/rdatastruct.h>
 147 #include <dns/rdatatype.h>
 148 #include <dns/result.h>
 149
 150 #include <irs/context.h>
 151 #include <irs/netdb.h>
 152 #include <irs/resconf.h>
 153
 154 #define SA(addr)        ((struct sockaddr *)(addr))
 155 #define SIN(addr)       ((struct sockaddr_in *)(addr))
 156 #define SIN6(addr)      ((struct sockaddr_in6 *)(addr))
 157 #define SLOCAL(addr)    ((struct sockaddr_un *)(addr))
 158
 159 /*! \struct addrinfo
 160  */
 161 static struct addrinfo
 162         *ai_concat(struct addrinfo *ai1, struct addrinfo *ai2),
 163         *ai_reverse(struct addrinfo *oai),
 164         *ai_clone(struct addrinfo *oai, int family),
 165         *ai_alloc(int family, int addrlen);
 166 #ifdef AF_LOCAL
 167 static int get_local(const char *name, int socktype, struct addrinfo **res);
 168 #endif
 169
 170 static int
 171 resolve_name(int family, const char *hostname, int flags,
 172              struct addrinfo **aip, int socktype, int port);
 173
 174 static int add_ipv4(const char *hostname, int flags, struct addrinfo **aip,
 175                     int socktype, int port);
 176 static int add_ipv6(const char *hostname, int flags, struct addrinfo **aip,
 177                     int socktype, int port);
 178 static void set_order(int, int (**)(const char *, int, struct addrinfo **,
 179                                     int, int));
 180
 181 #define FOUND_IPV4      0x1
 182 #define FOUND_IPV6      0x2
 183 #define FOUND_MAX       2
 184
 185 #define ISC_AI_MASK (AI_PASSIVE|AI_CANONNAME|AI_NUMERICHOST)
 186 /*%
 187  * Get a list of IP addresses and port numbers for host hostname and
 188  * service servname.
 189  */
 190 int
 191 getaddrinfo(const char *hostname, const char *servname,
 192             const struct addrinfo *hints, struct addrinfo **res)
 193 {
 194         struct servent *sp;
 195         const char *proto;
 196         int family, socktype, flags, protocol;
 197         struct addrinfo *ai, *ai_list;
 198         int err = 0;
 199         int port, i;
 200         int (*net_order[FOUND_MAX+1])(const char *, int, struct addrinfo **,
 201                                       int, int);
 202
 203         if (hostname == NULL && servname == NULL)
 204                 return (EAI_NONAME);
 205
 206         proto = NULL;
 207         if (hints != NULL) {
 208                 if ((hints->ai_flags & ~(ISC_AI_MASK)) != 0)
 209                         return (EAI_BADFLAGS);
 210                 if (hints->ai_addrlen || hints->ai_canonname ||
 211                     hints->ai_addr || hints->ai_next) {
 212                         errno = EINVAL;
 213                         return (EAI_SYSTEM);
 214                 }
 215                 family = hints->ai_family;
 216                 socktype = hints->ai_socktype;
 217                 protocol = hints->ai_protocol;
 218                 flags = hints->ai_flags;
 219                 switch (family) {
 220                 case AF_UNSPEC:
 221                         switch (hints->ai_socktype) {
 222                         case SOCK_STREAM:
 223                                 proto = "tcp";
 224                                 break;
 225                         case SOCK_DGRAM:
 226                                 proto = "udp";
 227                                 break;
 228                         }
 229                         break;
 230                 case AF_INET:
 231                 case AF_INET6:
 232                         switch (hints->ai_socktype) {
 233                         case 0:
 234                                 break;
 235                         case SOCK_STREAM:
 236                                 proto = "tcp";
 237                                 break;
 238                         case SOCK_DGRAM:
 239                                 proto = "udp";
 240                                 break;
 241                         case SOCK_RAW:
 242                                 break;
 243                         default:
 244                                 return (EAI_SOCKTYPE);
 245                         }
 246                         break;
 247 #ifdef  AF_LOCAL
 248                 case AF_LOCAL:
 249                         switch (hints->ai_socktype) {
 250                         case 0:
 251                                 break;
 252                         case SOCK_STREAM:
 253                                 break;
 254                         case SOCK_DGRAM:
 255                                 break;
 256                         default:
 257                                 return (EAI_SOCKTYPE);
 258                         }
 259                         break;
 260 #endif
 261                 default:
 262                         return (EAI_FAMILY);
 263                 }
 264         } else {
 265                 protocol = 0;
 266                 family = 0;
 267                 socktype = 0;
 268                 flags = 0;
 269         }
 270
 271 #ifdef  AF_LOCAL
 272         /*!
 273          * First, deal with AF_LOCAL.  If the family was not set,
 274          * then assume AF_LOCAL if the first character of the
 275          * hostname/servname is '/'.
 276          */
 277
 278         if (hostname != NULL &&
 279             (family == AF_LOCAL || (family == 0 && *hostname == '/')))
 280                 return (get_local(hostname, socktype, res));
 281
 282         if (servname != NULL &&
 283             (family == AF_LOCAL || (family == 0 && *servname == '/')))
 284                 return (get_local(servname, socktype, res));
 285 #endif
 286
 287         /*
 288          * Ok, only AF_INET and AF_INET6 left.
 289          */
 290         ai_list = NULL;
 291
 292         /*
 293          * First, look up the service name (port) if it was
 294          * requested.  If the socket type wasn't specified, then
 295          * try and figure it out.
 296          */
 297         if (servname != NULL) {
 298                 char *e;
 299
 300                 port = strtol(servname, &e, 10);
 301                 if (*e == '\0') {
 302                         if (socktype == 0)
 303                                 return (EAI_SOCKTYPE);
 304                         if (port < 0 || port > 65535)
 305                                 return (EAI_SERVICE);
 306                         port = htons((unsigned short) port);
 307                 } else {
 308                         sp = getservbyname(servname, proto);
 309                         if (sp == NULL)
 310                                 return (EAI_SERVICE);
 311                         port = sp->s_port;
 312                         if (socktype == 0) {
 313                                 if (strcmp(sp->s_proto, "tcp") == 0)
 314                                         socktype = SOCK_STREAM;
 315                                 else if (strcmp(sp->s_proto, "udp") == 0)
 316                                         socktype = SOCK_DGRAM;
 317                         }
 318                 }
 319         } else
 320                 port = 0;
 321
 322         /*
 323          * Next, deal with just a service name, and no hostname.
 324          * (we verified that one of them was non-null up above).
 325          */
 326         if (hostname == NULL && (flags & AI_PASSIVE) != 0) {
 327                 if (family == AF_INET || family == 0) {
 328                         ai = ai_alloc(AF_INET, sizeof(struct sockaddr_in));
 329                         if (ai == NULL)
 330                                 return (EAI_MEMORY);
 331                         ai->ai_socktype = socktype;
 332                         ai->ai_protocol = protocol;
 333                         SIN(ai->ai_addr)->sin_port = port;
 334                         ai->ai_next = ai_list;
 335                         ai_list = ai;
 336                 }
 337
 338                 if (family == AF_INET6 || family == 0) {
 339                         ai = ai_alloc(AF_INET6, sizeof(struct sockaddr_in6));
 340                         if (ai == NULL) {
 341                                 freeaddrinfo(ai_list);
 342                                 return (EAI_MEMORY);
 343                         }
 344                         ai->ai_socktype = socktype;
 345                         ai->ai_protocol = protocol;
 346                         SIN6(ai->ai_addr)->sin6_port = port;
 347                         ai->ai_next = ai_list;
 348                         ai_list = ai;
 349                 }
 350
 351                 *res = ai_list;
 352                 return (0);
 353         }
 354
 355         /*
 356          * If the family isn't specified or AI_NUMERICHOST specified, check
 357          * first to see if it is a numeric address.
 358          * Though the gethostbyname2() routine will recognize numeric addresses,
 359          * it will only recognize the format that it is being called for.  Thus,
 360          * a numeric AF_INET address will be treated by the AF_INET6 call as
 361          * a domain name, and vice versa.  Checking for both numerics here
 362          * avoids that.
 363          */
 364         if (hostname != NULL &&
 365             (family == 0 || (flags & AI_NUMERICHOST) != 0)) {
 366                 char abuf[sizeof(struct in6_addr)];
 367                 char nbuf[NI_MAXHOST];
 368                 int addrsize, addroff;
 369 #ifdef IRS_HAVE_SIN6_SCOPE_ID
 370                 char *p, *ep;
 371                 char ntmp[NI_MAXHOST];
 372                 isc_uint32_t scopeid;
 373 #endif
 374
 375 #ifdef IRS_HAVE_SIN6_SCOPE_ID
 376                 /*
 377                  * Scope identifier portion.
 378                  */
 379                 ntmp[0] = '\0';
 380                 if (strchr(hostname, '%') != NULL) {
 381                         strncpy(ntmp, hostname, sizeof(ntmp) - 1);
 382                         ntmp[sizeof(ntmp) - 1] = '\0';
 383                         p = strchr(ntmp, '%');
 384                         ep = NULL;
 385
 386                         /*
 387                          * Vendors may want to support non-numeric
 388                          * scopeid around here.
 389                          */
 390
 391                         if (p != NULL)
 392                                 scopeid = (isc_uint32_t)strtoul(p + 1,
 393                                                                 &ep, 10);
 394                         if (p != NULL && ep != NULL && ep[0] == '\0')
 395                                 *p = '\0';
 396                         else {
 397                                 ntmp[0] = '\0';
 398                                 scopeid = 0;
 399                         }
 400                 } else
 401                         scopeid = 0;
 402 #endif
 403
 404                 if (inet_pton(AF_INET, hostname, (struct in_addr *)abuf)
 405                     == 1) {
 406                         if (family == AF_INET6) {
 407                                 /*
 408                                  * Convert to a V4 mapped address.
 409                                  */
 410                                 struct in6_addr *a6 = (struct in6_addr *)abuf;
 411                                 memcpy(&a6->s6_addr[12], &a6->s6_addr[0], 4);
 412                                 memset(&a6->s6_addr[10], 0xff, 2);
 413                                 memset(&a6->s6_addr[0], 0, 10);
 414                                 goto inet6_addr;
 415                         }
 416                         addrsize = sizeof(struct in_addr);
 417                         addroff = (char *)(&SIN(0)->sin_addr) - (char *)0;
 418                         family = AF_INET;
 419                         goto common;
 420 #ifdef IRS_HAVE_SIN6_SCOPE_ID
 421                 } else if (ntmp[0] != '\0' &&
 422                            inet_pton(AF_INET6, ntmp, abuf) == 1) {
 423                         if (family && family != AF_INET6)
 424                                 return (EAI_NONAME);
 425                         addrsize = sizeof(struct in6_addr);
 426                         addroff = (char *)(&SIN6(0)->sin6_addr) - (char *)0;
 427                         family = AF_INET6;
 428                         goto common;
 429 #endif
 430                 } else if (inet_pton(AF_INET6, hostname, abuf) == 1) {
 431                         if (family != 0 && family != AF_INET6)
 432                                 return (EAI_NONAME);
 433                 inet6_addr:
 434                         addrsize = sizeof(struct in6_addr);
 435                         addroff = (char *)(&SIN6(0)->sin6_addr) - (char *)0;
 436                         family = AF_INET6;
 437
 438                 common:
 439                         ai = ai_alloc(family,
 440                                       ((family == AF_INET6) ?
 441                                        sizeof(struct sockaddr_in6) :
 442                                        sizeof(struct sockaddr_in)));
 443                         if (ai == NULL)
 444                                 return (EAI_MEMORY);
 445                         ai_list = ai;
 446                         ai->ai_socktype = socktype;
 447                         SIN(ai->ai_addr)->sin_port = port;
 448                         memcpy((char *)ai->ai_addr + addroff, abuf, addrsize);
 449                         if ((flags & AI_CANONNAME) != 0) {
 450 #ifdef IRS_HAVE_SIN6_SCOPE_ID
 451                                 if (ai->ai_family == AF_INET6)
 452                                         SIN6(ai->ai_addr)->sin6_scope_id =
 453                                                 scopeid;
 454 #endif
 455                                 if (getnameinfo(ai->ai_addr, ai->ai_addrlen,
 456                                                 nbuf, sizeof(nbuf), NULL, 0,
 457                                                 NI_NUMERICHOST) == 0) {
 458                                         ai->ai_canonname = strdup(nbuf);
 459                                         if (ai->ai_canonname == NULL) {
 460                                                 freeaddrinfo(ai);
 461                                                 return (EAI_MEMORY);
 462                                         }
 463                                 } else {
 464                                         /* XXX raise error? */
 465                                         ai->ai_canonname = NULL;
 466                                 }
 467                         }
 468                         goto done;
 469                 } else if ((flags & AI_NUMERICHOST) != 0) {
 470                         return (EAI_NONAME);
 471                 }
 472         }
 473
 474         if (hostname == NULL && (flags & AI_PASSIVE) == 0) {
 475                 set_order(family, net_order);
 476                 for (i = 0; i < FOUND_MAX; i++) {
 477                         if (net_order[i] == NULL)
 478                                 break;
 479                         err = (net_order[i])(hostname, flags, &ai_list,
 480                                              socktype, port);
 481                         if (err != 0) {
 482                                 if (ai_list != NULL)
 483                                         freeaddrinfo(ai_list);
 484                                 break;
 485                         }
 486                 }
 487         } else
 488                 err = resolve_name(family, hostname, flags, &ai_list,
 489                                    socktype, port);
 490
 491         if (ai_list == NULL) {
 492                 if (err == 0)
 493                         err = EAI_NONAME;
 494                 return (err);
 495         }
 496
 497 done:
 498         ai_list = ai_reverse(ai_list);
 499
 500         *res = ai_list;
 501         return (0);
 502 }
 503
 504 typedef struct gai_restrans {
 505         dns_clientrestrans_t    *xid;
 506         isc_boolean_t           is_inprogress;
 507         int                     error;
 508         struct addrinfo         ai_sentinel;
 509         struct gai_resstate     *resstate;
 510 } gai_restrans_t;
 511
 512 typedef struct gai_resstate {
 513         isc_mem_t                       *mctx;
 514         struct gai_statehead            *head;
 515         dns_fixedname_t                 fixedname;
 516         dns_name_t                      *qname;
 517         gai_restrans_t                  *trans4;
 518         gai_restrans_t                  *trans6;
 519         ISC_LINK(struct gai_resstate)   link;
 520 } gai_resstate_t;
 521
 522 typedef struct gai_statehead {
 523         int                             ai_family;
 524         int                             ai_flags;
 525         int                             ai_socktype;
 526         int                             ai_port;
 527         isc_appctx_t                    *actx;
 528         dns_client_t                    *dnsclient;
 529         ISC_LIST(struct gai_resstate)   resstates;
 530         unsigned int                    activestates;
 531 } gai_statehead_t;
 532
 533 static isc_result_t
 534 make_resstate(isc_mem_t *mctx, gai_statehead_t *head, const char *hostname,
 535               const char *domain, gai_resstate_t **statep)
 536 {
 537         isc_result_t result;
 538         gai_resstate_t *state;
 539         dns_fixedname_t fixeddomain;
 540         dns_name_t *qdomain;
 541         size_t namelen;
 542         isc_buffer_t b;
 543         isc_boolean_t need_v4 = ISC_FALSE;
 544         isc_boolean_t need_v6 = ISC_FALSE;
 545
 546         state = isc_mem_get(mctx, sizeof(*state));
 547         if (state == NULL)
 548                 return (ISC_R_NOMEMORY);
 549
 550         /* Construct base domain name */
 551         namelen = strlen(domain);
 552         isc_buffer_init(&b, domain, namelen);
 553         isc_buffer_add(&b, namelen);
 554         dns_fixedname_init(&fixeddomain);
 555         qdomain = dns_fixedname_name(&fixeddomain);
 556         result = dns_name_fromtext(qdomain, &b, dns_rootname, 0, NULL);
 557         if (result != ISC_R_SUCCESS) {
 558                 isc_mem_put(mctx, state, sizeof(*state));
 559                 return (result);
 560         }
 561
 562         /* Construct query name */
 563         namelen = strlen(hostname);
 564         isc_buffer_init(&b, hostname, namelen);
 565         isc_buffer_add(&b, namelen);
 566         dns_fixedname_init(&state->fixedname);
 567         state->qname = dns_fixedname_name(&state->fixedname);
 568         result = dns_name_fromtext(state->qname, &b, qdomain, 0, NULL);
 569         if (result != ISC_R_SUCCESS) {
 570                 isc_mem_put(mctx, state, sizeof(*state));
 571                 return (result);
 572         }
 573
 574         if (head->ai_family == AF_UNSPEC || head->ai_family == AF_INET)
 575                 need_v4 = ISC_TRUE;
 576         if (head->ai_family == AF_UNSPEC || head->ai_family == AF_INET6)
 577                 need_v6 = ISC_TRUE;
 578
 579         state->trans6 = NULL;
 580         state->trans4 = NULL;
 581         if (need_v4) {
 582                 state->trans4 = isc_mem_get(mctx, sizeof(gai_restrans_t));
 583                 if (state->trans4 == NULL) {
 584                         isc_mem_put(mctx, state, sizeof(*state));
 585                         return (ISC_R_NOMEMORY);
 586                 }
 587                 state->trans4->error = 0;
 588                 state->trans4->xid = NULL;
 589                 state->trans4->resstate = state;
 590                 state->trans4->is_inprogress = ISC_TRUE;
 591                 state->trans4->ai_sentinel.ai_next = NULL;
 592         }
 593         if (need_v6) {
 594                 state->trans6 = isc_mem_get(mctx, sizeof(gai_restrans_t));
 595                 if (state->trans6 == NULL) {
 596                         if (state->trans4 != NULL)
 597                                 isc_mem_put(mctx, state->trans4,
 598                                             sizeof(*state->trans4));
 599                         isc_mem_put(mctx, state, sizeof(*state));
 600                         return (ISC_R_NOMEMORY);
 601                 }
 602                 state->trans6->error = 0;
 603                 state->trans6->xid = NULL;
 604                 state->trans6->resstate = state;
 605                 state->trans6->is_inprogress = ISC_TRUE;
 606                 state->trans6->ai_sentinel.ai_next = NULL;
 607         }
 608
 609         state->mctx = mctx;
 610         state->head = head;
 611         ISC_LINK_INIT(state, link);
 612
 613         *statep = state;
 614
 615         return (ISC_R_SUCCESS);
 616 }
 617
 618 static isc_result_t
 619 make_resstates(isc_mem_t *mctx, const char *hostname, gai_statehead_t *head,
 620                irs_resconf_t *resconf)
 621 {
 622         isc_result_t result;
 623         irs_resconf_searchlist_t *searchlist;
 624         irs_resconf_search_t *searchent;
 625         gai_resstate_t *resstate, *resstate0;
 626
 627         resstate0 = NULL;
 628         result = make_resstate(mctx, head, hostname, ".", &resstate0);
 629         if (result != ISC_R_SUCCESS)
 630                 return (result);
 631
 632         searchlist = irs_resconf_getsearchlist(resconf);
 633         for (searchent = ISC_LIST_HEAD(*searchlist); searchent != NULL;
 634              searchent = ISC_LIST_NEXT(searchent, link)) {
 635                 resstate = NULL;
 636                 result = make_resstate(mctx, head, hostname,
 637                                        (const char *)searchent->domain,
 638                                        &resstate);
 639                 if (result != ISC_R_SUCCESS)
 640                         break;
 641
 642                 ISC_LIST_APPEND(head->resstates, resstate, link);
 643                 head->activestates++;
 644         }
 645
 646         /*
 647          * Insert the original hostname either at the head or the tail of the
 648          * state list, depending on the number of labels contained in the
 649          * original name and the 'ndots' configuration parameter.
 650          */
 651         if (dns_name_countlabels(resstate0->qname) >
 652             irs_resconf_getndots(resconf) + 1) {
 653                 ISC_LIST_PREPEND(head->resstates, resstate0, link);
 654         } else
 655                 ISC_LIST_APPEND(head->resstates, resstate0, link);
 656         head->activestates++;
 657
 658         if (result != ISC_R_SUCCESS) {
 659                 while ((resstate = ISC_LIST_HEAD(head->resstates)) != NULL) {
 660                         ISC_LIST_UNLINK(head->resstates, resstate, link);
 661                         if (resstate->trans4 != NULL) {
 662                                 isc_mem_put(mctx, resstate->trans4,
 663                                             sizeof(*resstate->trans4));
 664                         }
 665                         if (resstate->trans6 != NULL) {
 666                                 isc_mem_put(mctx, resstate->trans6,
 667                                             sizeof(*resstate->trans6));
 668                         }
 669
 670                         isc_mem_put(mctx, resstate, sizeof(*resstate));
 671                 }
 672         }
 673
 674         return (result);
 675 }
 676
 677 static void
 678 process_answer(isc_task_t *task, isc_event_t *event) {
 679         int error = 0, family;
 680         gai_restrans_t *trans = event->ev_arg;
 681         gai_resstate_t *resstate;
 682         dns_clientresevent_t *rev = (dns_clientresevent_t *)event;
 683         dns_rdatatype_t qtype;
 684         dns_name_t *name;
 685
 686         REQUIRE(trans != NULL);
 687         resstate = trans->resstate;
 688         REQUIRE(resstate != NULL);
 689         REQUIRE(task != NULL);
 690
 691         if (trans == resstate->trans4) {
 692                 family = AF_INET;
 693                 qtype = dns_rdatatype_a;
 694         } else {
 695                 INSIST(trans == resstate->trans6);
 696                 family = AF_INET6;
 697                 qtype = dns_rdatatype_aaaa;
 698         }
 699
 700         INSIST(trans->is_inprogress);
 701         trans->is_inprogress = ISC_FALSE;
 702
 703         switch (rev->result) {
 704         case ISC_R_SUCCESS:
 705         case DNS_R_NCACHENXDOMAIN: /* treat this as a fatal error? */
 706         case DNS_R_NCACHENXRRSET:
 707                 break;
 708         default:
 709                 switch (rev->vresult) {
 710                 case DNS_R_SIGINVALID:
 711                 case DNS_R_SIGEXPIRED:
 712                 case DNS_R_SIGFUTURE:
 713                 case DNS_R_KEYUNAUTHORIZED:
 714                 case DNS_R_MUSTBESECURE:
 715                 case DNS_R_COVERINGNSEC:
 716                 case DNS_R_NOTAUTHORITATIVE:
 717                 case DNS_R_NOVALIDKEY:
 718                 case DNS_R_NOVALIDDS:
 719                 case DNS_R_NOVALIDSIG:
 720                         error = EAI_INSECUREDATA;
 721                         break;
 722                 default:
 723                         error = EAI_FAIL;
 724                 }
 725                 goto done;
 726         }
 727
 728         /* Parse the response and construct the addrinfo chain */
 729         for (name = ISC_LIST_HEAD(rev->answerlist); name != NULL;
 730              name = ISC_LIST_NEXT(name, link)) {
 731                 isc_result_t result;
 732                 dns_rdataset_t *rdataset;
 733                 isc_buffer_t b;
 734                 isc_region_t r;
 735                 char t[1024];
 736
 737                 for (rdataset = ISC_LIST_HEAD(name->list);
 738                      rdataset != NULL;
 739                      rdataset = ISC_LIST_NEXT(rdataset, link)) {
 740                         if (!dns_rdataset_isassociated(rdataset))
 741                                 continue;
 742                         if (rdataset->type != qtype)
 743                                 continue;
 744
 745                         if ((resstate->head->ai_flags & AI_CANONNAME) != 0) {
 746                                 isc_buffer_init(&b, t, sizeof(t));
 747                                 result = dns_name_totext(name, ISC_TRUE, &b);
 748                                 if (result != ISC_R_SUCCESS) {
 749                                         error = EAI_FAIL;
 750                                         goto done;
 751                                 }
 752                                 isc_buffer_putuint8(&b, '\0');
 753                                 isc_buffer_usedregion(&b, &r);
 754                         }
 755
 756                         for (result = dns_rdataset_first(rdataset);
 757                              result == ISC_R_SUCCESS;
 758                              result = dns_rdataset_next(rdataset)) {
 759                                 struct addrinfo *ai;
 760                                 dns_rdata_t rdata;
 761                                 dns_rdata_in_a_t rdata_a;
 762                                 dns_rdata_in_aaaa_t rdata_aaaa;
 763
 764                                 ai = ai_alloc(family,
 765                                               ((family == AF_INET6) ?
 766                                                sizeof(struct sockaddr_in6) :
 767                                                sizeof(struct sockaddr_in)));
 768                                 if (ai == NULL) {
 769                                         error = EAI_MEMORY;
 770                                         goto done;
 771                                 }
 772                                 ai->ai_socktype = resstate->head->ai_socktype;
 773                                 ai->ai_next = trans->ai_sentinel.ai_next;
 774                                 trans->ai_sentinel.ai_next = ai;
 775
 776                                 /*
 777                                  * Set AF-specific parameters
 778                                  * (IPv4/v6 address/port)
 779                                  */
 780                                 dns_rdata_init(&rdata);
 781                                 switch (family) {
 782                                 case AF_INET:
 783                                         dns_rdataset_current(rdataset, &rdata);
 784                                         dns_rdata_tostruct(&rdata, &rdata_a,
 785                                                            NULL);
 786
 787                                         SIN(ai->ai_addr)->sin_port =
 788                                                 resstate->head->ai_port;
 789                                         memcpy(&SIN(ai->ai_addr)->sin_addr,
 790                                                &rdata_a.in_addr, 4);
 791                                         dns_rdata_freestruct(&rdata_a);
 792                                         break;
 793                                 case AF_INET6:
 794                                         dns_rdataset_current(rdataset, &rdata);
 795                                         dns_rdata_tostruct(&rdata, &rdata_aaaa,
 796                                                            NULL);
 797                                         SIN6(ai->ai_addr)->sin6_port =
 798                                                 resstate->head->ai_port;
 799                                         memcpy(&SIN6(ai->ai_addr)->sin6_addr,
 800                                                &rdata_aaaa.in6_addr, 16);
 801                                         dns_rdata_freestruct(&rdata_aaaa);
 802                                         break;
 803                                 }
 804
 805                                 if ((resstate->head->ai_flags & AI_CANONNAME)
 806                                     != 0) {
 807                                         ai->ai_canonname =
 808                                                 strdup((const char *)r.base);
 809                                         if (ai->ai_canonname == NULL) {
 810                                                 error = EAI_MEMORY;
 811                                                 goto done;
 812                                         }
 813                                 }
 814                         }
 815                 }
 816         }
 817
 818  done:
 819         dns_client_freeresanswer(resstate->head->dnsclient, &rev->answerlist);
 820         dns_client_destroyrestrans(&trans->xid);
 821
 822         isc_event_free(&event);
 823
 824         /* Make sure that error == 0 iff we have a non-empty list */
 825         if (error == 0) {
 826                 if (trans->ai_sentinel.ai_next == NULL)
 827                         error = EAI_NONAME;
 828         } else {
 829                 if (trans->ai_sentinel.ai_next != NULL) {
 830                         freeaddrinfo(trans->ai_sentinel.ai_next);
 831                         trans->ai_sentinel.ai_next = NULL;
 832                 }
 833         }
 834         trans->error = error;
 835
 836         /* Check whether we are done */
 837         if ((resstate->trans4 == NULL || !resstate->trans4->is_inprogress) &&
 838             (resstate->trans6 == NULL || !resstate->trans6->is_inprogress)) {
 839                 /*
 840                  * We're done for this state.  If there is no other outstanding
 841                  * state, we can exit.
 842                  */
 843                 resstate->head->activestates--;
 844                 if (resstate->head->activestates == 0) {
 845                         isc_app_ctxsuspend(resstate->head->actx);
 846                         return;
 847                 }
 848
 849                 /*
 850                  * There are outstanding states, but if we are at the head
 851                  * of the state list (i.e., at the highest search priority)
 852                  * and have any answer, we can stop now by canceling the
 853                  * others.
 854                  */
 855                 if (resstate == ISC_LIST_HEAD(resstate->head->resstates)) {
 856                         if ((resstate->trans4 != NULL &&
 857                              resstate->trans4->ai_sentinel.ai_next != NULL) ||
 858                             (resstate->trans6 != NULL &&
 859                              resstate->trans6->ai_sentinel.ai_next != NULL)) {
 860                                 gai_resstate_t *rest;
 861
 862                                 for (rest = ISC_LIST_NEXT(resstate, link);
 863                                      rest != NULL;
 864                                      rest = ISC_LIST_NEXT(rest, link)) {
 865                                         if (rest->trans4 != NULL &&
 866                                             rest->trans4->xid != NULL)
 867                                                 dns_client_cancelresolve(
 868                                                         rest->trans4->xid);
 869                                         if (rest->trans6 != NULL &&
 870                                             rest->trans6->xid != NULL)
 871                                                 dns_client_cancelresolve(
 872                                                         rest->trans6->xid);
 873                                 }
 874                         } else {
 875                                 /*
 876                                  * This search fails, so we move to the tail
 877                                  * of the list so that the next entry will
 878                                  * have the highest priority.
 879                                  */
 880                                 ISC_LIST_UNLINK(resstate->head->resstates,
 881                                                 resstate, link);
 882                                 ISC_LIST_APPEND(resstate->head->resstates,
 883                                                 resstate, link);
 884                         }
 885                 }
 886         }
 887 }
 888
 889 static int
 890 resolve_name(int family, const char *hostname, int flags,
 891              struct addrinfo **aip, int socktype, int port)
 892 {
 893         isc_result_t result;
 894         irs_context_t *irsctx;
 895         irs_resconf_t *conf;
 896         isc_mem_t *mctx;
 897         isc_appctx_t *actx;
 898         isc_task_t *task;
 899         int terror = 0;
 900         int error = 0;
 901         dns_client_t *client;
 902         gai_resstate_t *resstate;
 903         gai_statehead_t head;
 904         isc_boolean_t all_fail = ISC_TRUE;
 905
 906         /* get IRS context and the associated parameters */
 907         irsctx = NULL;
 908         result = irs_context_get(&irsctx);
 909         if (result != ISC_R_SUCCESS)
 910                 return (EAI_FAIL);
 911         actx = irs_context_getappctx(irsctx);
 912
 913         mctx = irs_context_getmctx(irsctx);
 914         task = irs_context_gettask(irsctx);
 915         conf = irs_context_getresconf(irsctx);
 916         client = irs_context_getdnsclient(irsctx);
 917
 918         /* construct resolution states */
 919         head.activestates = 0;
 920         head.ai_family = family;
 921         head.ai_socktype = socktype;
 922         head.ai_flags = flags;
 923         head.ai_port = port;
 924         head.actx = actx;
 925         head.dnsclient = client;
 926         ISC_LIST_INIT(head.resstates);
 927         result = make_resstates(mctx, hostname, &head, conf);
 928         if (result != ISC_R_SUCCESS)
 929                 return (EAI_FAIL);
 930
 931         for (resstate = ISC_LIST_HEAD(head.resstates);
 932              resstate != NULL; resstate = ISC_LIST_NEXT(resstate, link)) {
 933                 if (resstate->trans4 != NULL) {
 934                         result = dns_client_startresolve(client,
 935                                                          resstate->qname,
 936                                                          dns_rdataclass_in,
 937                                                          dns_rdatatype_a,
 938                                                          0, task,
 939                                                          process_answer,
 940                                                          resstate->trans4,
 941                                                          &resstate->trans4->xid);
 942                         if (result == ISC_R_SUCCESS) {
 943                                 resstate->trans4->is_inprogress = ISC_TRUE;
 944                                 all_fail = ISC_FALSE;
 945                         } else
 946                                 resstate->trans4->is_inprogress = ISC_FALSE;
 947                 }
 948                 if (resstate->trans6 != NULL) {
 949                         result = dns_client_startresolve(client,
 950                                                          resstate->qname,
 951                                                          dns_rdataclass_in,
 952                                                          dns_rdatatype_aaaa,
 953                                                          0, task,
 954                                                          process_answer,
 955                                                          resstate->trans6,
 956                                                          &resstate->trans6->xid);
 957                         if (result == ISC_R_SUCCESS) {
 958                                 resstate->trans6->is_inprogress = ISC_TRUE;
 959                                 all_fail = ISC_FALSE;
 960                         } else
 961                                 resstate->trans6->is_inprogress= ISC_FALSE;
 962                 }
 963         }
 964         if (!all_fail) {
 965                 /* Start all the events */
 966                 isc_app_ctxrun(actx);
 967         } else
 968                 error = EAI_FAIL;
 969
 970         /* Cleanup */
 971         while ((resstate = ISC_LIST_HEAD(head.resstates)) != NULL) {
 972                 int terror4 = 0, terror6 = 0;
 973
 974                 ISC_LIST_UNLINK(head.resstates, resstate, link);
 975
 976                 if (*aip == NULL) {
 977                         struct addrinfo *sentinel4 = NULL;
 978                         struct addrinfo *sentinel6 = NULL;
 979
 980                         if (resstate->trans4 != NULL) {
 981                                 sentinel4 =
 982                                         resstate->trans4->ai_sentinel.ai_next;
 983                                 resstate->trans4->ai_sentinel.ai_next = NULL;
 984                         }
 985                         if (resstate->trans6 != NULL) {
 986                                 sentinel6 =
 987                                         resstate->trans6->ai_sentinel.ai_next;
 988                                 resstate->trans6->ai_sentinel.ai_next = NULL;
 989                         }
 990                         *aip = ai_concat(sentinel4, sentinel6);
 991                 }
 992
 993                 if (resstate->trans4 != NULL) {
 994                         INSIST(resstate->trans4->xid == NULL);
 995                         terror4 = resstate->trans4->error;
 996                         isc_mem_put(mctx, resstate->trans4,
 997                                     sizeof(*resstate->trans4));
 998                 }
 999                 if (resstate->trans6 != NULL) {
1000                         INSIST(resstate->trans6->xid == NULL);
1001                         terror6 = resstate->trans6->error;
1002                         isc_mem_put(mctx, resstate->trans6,
1003                                     sizeof(*resstate->trans6));
1004                 }
1005
1006                 /*
1007                  * If the entire lookup fails, we need to choose an appropriate
1008                  * error code from individual codes.  We'll try to provide as
1009                  * specific a code as possible.  In general, we are going to
1010                  * find an error code other than EAI_NONAME (which is too
1011                  * generic and may actually not be problematic in some cases).
1012                  * EAI_NONAME will be set below if no better code is found.
1013                  */
1014                 if (terror == 0 || terror == EAI_NONAME) {
1015                         if (terror4 != 0 && terror4 != EAI_NONAME)
1016                                 terror = terror4;
1017                         else if (terror6 != 0 && terror6 != EAI_NONAME)
1018                                 terror = terror6;
1019                 }
1020
1021                 isc_mem_put(mctx, resstate, sizeof(*resstate));
1022         }
1023
1024         if (*aip == NULL) {
1025                 error = terror;
1026                 if (error == 0)
1027                         error = EAI_NONAME;
1028         }
1029
1030 #if 1   /*  XXX: enabled for finding leaks.  should be cleaned up later. */
1031         isc_app_ctxfinish(actx);
1032         irs_context_destroy(&irsctx);
1033 #endif
1034
1035         return (error);
1036 }
1037
1038 static char *
1039 irs_strsep(char **stringp, const char *delim) {
1040         char *string = *stringp;
1041         char *s;
1042         const char *d;
1043         char sc, dc;
1044
1045         if (string == NULL)
1046                 return (NULL);
1047
1048         for (s = string; *s != '\0'; s++) {
1049                 sc = *s;
1050                 for (d = delim; (dc = *d) != '\0'; d++)
1051                         if (sc == dc) {
1052                                 *s++ = '\0';
1053                                 *stringp = s;
1054                                 return (string);
1055                         }
1056         }
1057         *stringp = NULL;
1058         return (string);
1059 }
1060
1061 static void
1062 set_order(int family, int (**net_order)(const char *, int, struct addrinfo **,
1063                                         int, int))
1064 {
1065         char *order, *tok;
1066         int found;
1067
1068         if (family) {
1069                 switch (family) {
1070                 case AF_INET:
1071                         *net_order++ = add_ipv4;
1072                         break;
1073                 case AF_INET6:
1074                         *net_order++ = add_ipv6;
1075                         break;
1076                 }
1077         } else {
1078                 order = getenv("NET_ORDER");
1079                 found = 0;
1080                 while (order != NULL) {
1081                         /*
1082                          * We ignore any unknown names.
1083                          */
1084                         tok = irs_strsep(&order, ":");
1085                         if (strcasecmp(tok, "inet6") == 0) {
1086                                 if ((found & FOUND_IPV6) == 0)
1087                                         *net_order++ = add_ipv6;
1088                                 found |= FOUND_IPV6;
1089                         } else if (strcasecmp(tok, "inet") == 0 ||
1090                             strcasecmp(tok, "inet4") == 0) {
1091                                 if ((found & FOUND_IPV4) == 0)
1092                                         *net_order++ = add_ipv4;
1093                                 found |= FOUND_IPV4;
1094                         }
1095                 }
1096
1097                 /*
1098                  * Add in anything that we didn't find.
1099                  */
1100                 if ((found & FOUND_IPV4) == 0)
1101                         *net_order++ = add_ipv4;
1102                 if ((found & FOUND_IPV6) == 0)
1103                         *net_order++ = add_ipv6;
1104         }
1105         *net_order = NULL;
1106         return;
1107 }
1108
1109 static char v4_loop[4] = { 127, 0, 0, 1 };
1110
1111 static int
1112 add_ipv4(const char *hostname, int flags, struct addrinfo **aip,
1113          int socktype, int port)
1114 {
1115         struct addrinfo *ai;
1116
1117         UNUSED(hostname);
1118         UNUSED(flags);
1119
1120         ai = ai_clone(*aip, AF_INET); /* don't use ai_clone() */
1121         if (ai == NULL) {
1122                 freeaddrinfo(*aip);
1123                 return (EAI_MEMORY);
1124         }
1125
1126         *aip = ai;
1127         ai->ai_socktype = socktype;
1128         SIN(ai->ai_addr)->sin_port = port;
1129         memcpy(&SIN(ai->ai_addr)->sin_addr, v4_loop, 4);
1130
1131         return (0);
1132 }
1133
1134 static char v6_loop[16] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 };
1135
1136 static int
1137 add_ipv6(const char *hostname, int flags, struct addrinfo **aip,
1138          int socktype, int port)
1139 {
1140         struct addrinfo *ai;
1141
1142         UNUSED(hostname);
1143         UNUSED(flags);
1144
1145         ai = ai_clone(*aip, AF_INET6); /* don't use ai_clone() */
1146         if (ai == NULL) {
1147                 freeaddrinfo(*aip);
1148                 return (EAI_MEMORY);
1149         }
1150
1151         *aip = ai;
1152         ai->ai_socktype = socktype;
1153         SIN6(ai->ai_addr)->sin6_port = port;
1154         memcpy(&SIN6(ai->ai_addr)->sin6_addr, v6_loop, 16);
1155
1156         return (0);
1157 }
1158
1159 /*% Free address info. */
1160 void
1161 freeaddrinfo(struct addrinfo *ai) {
1162         struct addrinfo *ai_next;
1163
1164         while (ai != NULL) {
1165                 ai_next = ai->ai_next;
1166                 if (ai->ai_addr != NULL)
1167                         free(ai->ai_addr);
1168                 if (ai->ai_canonname)
1169                         free(ai->ai_canonname);
1170                 free(ai);
1171                 ai = ai_next;
1172         }
1173 }
1174
1175 #ifdef AF_LOCAL
1176 static int
1177 get_local(const char *name, int socktype, struct addrinfo **res) {
1178         struct addrinfo *ai;
1179         struct sockaddr_un *slocal;
1180
1181         if (socktype == 0)
1182                 return (EAI_SOCKTYPE);
1183
1184         ai = ai_alloc(AF_LOCAL, sizeof(*slocal));
1185         if (ai == NULL)
1186                 return (EAI_MEMORY);
1187
1188         slocal = SLOCAL(ai->ai_addr);
1189         strncpy(slocal->sun_path, name, sizeof(slocal->sun_path));
1190
1191         ai->ai_socktype = socktype;
1192         /*
1193          * ai->ai_flags, ai->ai_protocol, ai->ai_canonname,
1194          * and ai->ai_next were initialized to zero.
1195          */
1196
1197         *res = ai;
1198         return (0);
1199 }
1200 #endif
1201
1202 /*!
1203  * Allocate an addrinfo structure, and a sockaddr structure
1204  * of the specificed length.  We initialize:
1205  *      ai_addrlen
1206  *      ai_family
1207  *      ai_addr
1208  *      ai_addr->sa_family
1209  *      ai_addr->sa_len (IRS_PLATFORM_HAVESALEN)
1210  * and everything else is initialized to zero.
1211  */
1212 static struct addrinfo *
1213 ai_alloc(int family, int addrlen) {
1214         struct addrinfo *ai;
1215
1216         ai = (struct addrinfo *)calloc(1, sizeof(*ai));
1217         if (ai == NULL)
1218                 return (NULL);
1219
1220         ai->ai_addr = SA(calloc(1, addrlen));
1221         if (ai->ai_addr == NULL) {
1222                 free(ai);
1223                 return (NULL);
1224         }
1225         ai->ai_addrlen = addrlen;
1226         ai->ai_family = family;
1227         ai->ai_addr->sa_family = family;
1228 #ifdef IRS_PLATFORM_HAVESALEN
1229         ai->ai_addr->sa_len = addrlen;
1230 #endif
1231         return (ai);
1232 }
1233
1234 static struct addrinfo *
1235 ai_clone(struct addrinfo *oai, int family) {
1236         struct addrinfo *ai;
1237
1238         ai = ai_alloc(family, ((family == AF_INET6) ?
1239             sizeof(struct sockaddr_in6) : sizeof(struct sockaddr_in)));
1240
1241         if (ai == NULL) {
1242                 if (oai != NULL)
1243                         freeaddrinfo(oai);
1244                 return (NULL);
1245         }
1246         if (oai == NULL)
1247                 return (ai);
1248
1249         ai->ai_flags = oai->ai_flags;
1250         ai->ai_socktype = oai->ai_socktype;
1251         ai->ai_protocol = oai->ai_protocol;
1252         ai->ai_canonname = NULL;
1253         ai->ai_next = oai;
1254         return (ai);
1255 }
1256
1257 static struct addrinfo *
1258 ai_reverse(struct addrinfo *oai) {
1259         struct addrinfo *nai, *tai;
1260
1261         nai = NULL;
1262
1263         while (oai != NULL) {
1264                 /*
1265                  * Grab one off the old list.
1266                  */
1267                 tai = oai;
1268                 oai = oai->ai_next;
1269                 /*
1270                  * Put it on the front of the new list.
1271                  */
1272                 tai->ai_next = nai;
1273                 nai = tai;
1274         }
1275         return (nai);
1276 }
1277
1278
1279 static struct addrinfo *
1280 ai_concat(struct addrinfo *ai1, struct addrinfo *ai2) {
1281         struct addrinfo *ai_tmp;
1282
1283         if (ai1 == NULL)
1284                 return (ai2);
1285         else if (ai2 == NULL)
1286                 return (ai1);
1287
1288         for (ai_tmp = ai1; ai_tmp != NULL && ai_tmp->ai_next != NULL;
1289              ai_tmp = ai_tmp->ai_next)
1290                 ;
1291
1292         ai_tmp->ai_next = ai2;
1293
1294         return (ai1);
1295 }