lib/libc/net/name6.c

   1 /*      $KAME: name6.c,v 1.25 2000/06/26 16:44:40 itojun Exp $  */
   2
   3 /*
   4  * Copyright (C) 1995, 1996, 1997, 1998, and 1999 WIDE Project.
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. Neither the name of the project nor the names of its contributors
  16  *    may be used to endorse or promote products derived from this software
  17  *    without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  */
  31 /*
  32  * ++Copyright++ 1985, 1988, 1993
  33  * -
  34  * Copyright (c) 1985, 1988, 1993
  35  *    The Regents of the University of California.  All rights reserved.
  36  *
  37  * Redistribution and use in source and binary forms, with or without
  38  * modification, are permitted provided that the following conditions
  39  * are met:
  40  * 1. Redistributions of source code must retain the above copyright
  41  *    notice, this list of conditions and the following disclaimer.
  42  * 2. Redistributions in binary form must reproduce the above copyright
  43  *    notice, this list of conditions and the following disclaimer in the
  44  *    documentation and/or other materials provided with the distribution.
  45  * 3. All advertising materials mentioning features or use of this software
  46  *    must display the following acknowledgement:
  47  *      This product includes software developed by the University of
  48  *      California, Berkeley and its contributors.
  49  * 4. Neither the name of the University nor the names of its contributors
  50  *    may be used to endorse or promote products derived from this software
  51  *    without specific prior written permission.
  52  *
  53  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  54  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  55  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  56  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  57  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  58  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  59  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  60  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  61  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  62  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  63  * SUCH DAMAGE.
  64  * -
  65  * Portions Copyright (c) 1993 by Digital Equipment Corporation.
  66  *
  67  * Permission to use, copy, modify, and distribute this software for any
  68  * purpose with or without fee is hereby granted, provided that the above
  69  * copyright notice and this permission notice appear in all copies, and that
  70  * the name of Digital Equipment Corporation not be used in advertising or
  71  * publicity pertaining to distribution of the document or software without
  72  * specific, written prior permission.
  73  *
  74  * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
  75  * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
  76  * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
  77  * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
  78  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  79  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
  80  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  81  * SOFTWARE.
  82  * -
  83  * --Copyright--
  84  *
  85  * $FreeBSD: src/lib/libc/net/name6.c,v 1.62 2007/07/31 16:09:41 bushman Exp $
  86  */
  87
  88 /*
  89  *      Atsushi Onoe <onoe@sm.sony.co.jp>
  90  */
  91
  92 #include "namespace.h"
  93 #include <sys/param.h>
  94 #include <sys/socket.h>
  95 #include <sys/time.h>
  96 #include <sys/queue.h>
  97 #include <netinet/in.h>
  98 #ifdef INET6
  99 #include <net/if.h>
 100 #include <net/if_var.h>
 101 #include <sys/sysctl.h>
 102 #include <sys/ioctl.h>
 103 #include <netinet6/in6_var.h>   /* XXX */
 104 #endif
 105
 106 #include <arpa/inet.h>
 107 #include <arpa/nameser.h>
 108
 109 #include <errno.h>
 110 #include <netdb.h>
 111 #include <resolv.h>
 112 #include <stdio.h>
 113 #include <stdlib.h>
 114 #include <string.h>
 115 #include <stdarg.h>
 116 #include <nsswitch.h>
 117 #include <unistd.h>
 118 #include "un-namespace.h"
 119 #include "netdb_private.h"
 120 #include "res_private.h"
 121
 122 #ifndef MAXALIASES
 123 #define MAXALIASES      10
 124 #endif
 125 #ifndef MAXADDRS
 126 #define MAXADDRS        20
 127 #endif
 128 #ifndef MAXDNAME
 129 #define MAXDNAME        1025
 130 #endif
 131
 132 #ifdef INET6
 133 #define ADDRLEN(af)     ((af) == AF_INET6 ? sizeof(struct in6_addr) : \
 134                                             sizeof(struct in_addr))
 135 #else
 136 #define ADDRLEN(af)     sizeof(struct in_addr)
 137 #endif
 138
 139 #define MAPADDR(ab, ina) \
 140 do {                                                                    \
 141         memcpy(&(ab)->map_inaddr, ina, sizeof(struct in_addr));         \
 142         memset((ab)->map_zero, 0, sizeof((ab)->map_zero));              \
 143         memset((ab)->map_one, 0xff, sizeof((ab)->map_one));             \
 144 } while (0)
 145 #define MAPADDRENABLED(flags) \
 146         (((flags) & AI_V4MAPPED) || \
 147          (((flags) & AI_V4MAPPED_CFG)))
 148
 149 union inx_addr {
 150         struct in_addr  in_addr;
 151 #ifdef INET6
 152         struct in6_addr in6_addr;
 153 #endif
 154         struct {
 155                 u_char  mau_zero[10];
 156                 u_char  mau_one[2];
 157                 struct in_addr mau_inaddr;
 158         }               map_addr_un;
 159 #define map_zero        map_addr_un.mau_zero
 160 #define map_one         map_addr_un.mau_one
 161 #define map_inaddr      map_addr_un.mau_inaddr
 162 };
 163
 164 struct policyqueue {
 165         TAILQ_ENTRY(policyqueue) pc_entry;
 166 #ifdef INET6
 167         struct in6_addrpolicy pc_policy;
 168 #endif
 169 };
 170 TAILQ_HEAD(policyhead, policyqueue);
 171
 172 #define AIO_SRCFLAG_DEPRECATED  0x1
 173
 174 struct hp_order {
 175         union {
 176                 struct sockaddr_storage aiou_ss;
 177                 struct sockaddr aiou_sa;
 178         } aio_src_un;
 179 #define aio_srcsa aio_src_un.aiou_sa
 180         u_int32_t aio_srcflag;
 181         int aio_srcscope;
 182         int aio_dstscope;
 183         struct policyqueue *aio_srcpolicy;
 184         struct policyqueue *aio_dstpolicy;
 185         union {
 186                 struct sockaddr_storage aiou_ss;
 187                 struct sockaddr aiou_sa;
 188         } aio_un;
 189 #define aio_sa aio_un.aiou_sa
 190         int aio_matchlen;
 191         char *aio_h_addr;
 192 };
 193
 194 static struct hostent   *_hpcopy(struct hostent *, int *);
 195 static struct hostent   *_hpaddr(int, const char *, void *, int *);
 196 #ifdef INET6
 197 static struct hostent   *_hpmerge(struct hostent *, struct hostent *, int *);
 198 static struct hostent   *_hpmapv6(struct hostent *, int *);
 199 #endif
 200 static struct hostent   *_hpsort(struct hostent *, res_state);
 201
 202 static struct hostent   *_hpreorder(struct hostent *);
 203 static int               get_addrselectpolicy(struct policyhead *);
 204 static void              free_addrselectpolicy(struct policyhead *);
 205 static struct policyqueue *match_addrselectpolicy(struct sockaddr *,
 206                                                   struct policyhead *);
 207 static void              set_source(struct hp_order *, struct policyhead *);
 208 static int               matchlen(struct sockaddr *, struct sockaddr *);
 209 static int               comp_dst(const void *, const void *);
 210 static int               gai_addr2scopetype(struct sockaddr *);
 211
 212 /*
 213  * Functions defined in RFC2553
 214  *      getipnodebyname, getipnodebyaddr, freehostent
 215  */
 216
 217 struct hostent *
 218 getipnodebyname(const char *name, int af, int flags, int *errp)
 219 {
 220         struct hostent *hp;
 221         union inx_addr addrbuf;
 222         res_state statp;
 223         u_long options;
 224
 225         switch (af) {
 226         case AF_INET:
 227 #ifdef INET6
 228         case AF_INET6:
 229 #endif
 230                 break;
 231         default:
 232                 *errp = NO_RECOVERY;
 233                 return NULL;
 234         }
 235
 236         if (flags & AI_ADDRCONFIG) {
 237                 int s;
 238
 239                 if ((s = _socket(af, SOCK_DGRAM, 0)) < 0)
 240                         return NULL;
 241                 /*
 242                  * TODO:
 243                  * Note that implementation dependent test for address
 244                  * configuration should be done everytime called
 245                  * (or apropriate interval),
 246                  * because addresses will be dynamically assigned or deleted.
 247                  */
 248                 _close(s);
 249         }
 250
 251 #ifdef INET6
 252         /* special case for literal address */
 253         if (inet_pton(AF_INET6, name, &addrbuf) == 1) {
 254                 if (af != AF_INET6) {
 255                         *errp = HOST_NOT_FOUND;
 256                         return NULL;
 257                 }
 258                 return _hpaddr(af, name, &addrbuf, errp);
 259         }
 260 #endif
 261         if (inet_aton(name, (struct in_addr *)&addrbuf) == 1) {
 262                 if (af != AF_INET) {
 263                         if (MAPADDRENABLED(flags)) {
 264                                 MAPADDR(&addrbuf, &addrbuf.in_addr);
 265                         } else {
 266                                 *errp = HOST_NOT_FOUND;
 267                                 return NULL;
 268                         }
 269                 }
 270                 return _hpaddr(af, name, &addrbuf, errp);
 271         }
 272
 273
 274         statp = __res_state();
 275         if ((statp->options & RES_INIT) == 0) {
 276                 if (res_ninit(statp) < 0) {
 277                         *errp = NETDB_INTERNAL;
 278                         return NULL;
 279                 }
 280         }
 281
 282         options = statp->options;
 283         statp->options &= ~RES_USE_INET6;
 284
 285         hp = gethostbyname2(name, af);
 286         hp = _hpcopy(hp, errp);
 287
 288 #ifdef INET6
 289         if (af == AF_INET6 && ((flags & AI_ALL) || hp == NULL) &&
 290             MAPADDRENABLED(flags)) {
 291                 struct hostent *hp2 = gethostbyname2(name, AF_INET);
 292                 if (hp == NULL)
 293                         if (hp2 == NULL)
 294                                 *errp = statp->res_h_errno;
 295                         else
 296                                 hp = _hpmapv6(hp2, errp);
 297                 else {
 298                         if (hp2 && strcmp(hp->h_name, hp2->h_name) == 0) {
 299                                 struct hostent *hpb = hp;
 300                                 hp = _hpmerge(hpb, hp2, errp);
 301                                 freehostent(hpb);
 302                         }
 303                 }
 304         }
 305 #endif
 306
 307         if (hp == NULL)
 308                 *errp = statp->res_h_errno;
 309
 310         statp->options = options;
 311         return _hpreorder(_hpsort(hp, statp));
 312 }
 313
 314 struct hostent *
 315 getipnodebyaddr(const void *src, size_t len, int af, int *errp)
 316 {
 317         struct hostent *hp;
 318         res_state statp;
 319         u_long options;
 320
 321 #ifdef INET6
 322         struct in6_addr addrbuf;
 323 #else
 324         struct in_addr addrbuf;
 325 #endif
 326
 327         switch (af) {
 328         case AF_INET:
 329                 if (len != sizeof(struct in_addr)) {
 330                         *errp = NO_RECOVERY;
 331                         return NULL;
 332                 }
 333                 if ((long)src & ~(sizeof(struct in_addr) - 1)) {
 334                         memcpy(&addrbuf, src, len);
 335                         src = &addrbuf;
 336                 }
 337                 if (((struct in_addr *)src)->s_addr == 0)
 338                         return NULL;
 339                 break;
 340 #ifdef INET6
 341         case AF_INET6:
 342                 if (len != sizeof(struct in6_addr)) {
 343                         *errp = NO_RECOVERY;
 344                         return NULL;
 345                 }
 346                 if ((long)src & ~(sizeof(struct in6_addr) / 2 - 1)) {   /*XXX*/
 347                         memcpy(&addrbuf, src, len);
 348                         src = &addrbuf;
 349                 }
 350                 if (IN6_IS_ADDR_UNSPECIFIED((struct in6_addr *)src))
 351                         return NULL;
 352                 if (IN6_IS_ADDR_V4MAPPED((struct in6_addr *)src)
 353                 ||  IN6_IS_ADDR_V4COMPAT((struct in6_addr *)src)) {
 354                         src = (char *)src +
 355                             (sizeof(struct in6_addr) - sizeof(struct in_addr));
 356                         af = AF_INET;
 357                         len = sizeof(struct in_addr);
 358                 }
 359                 break;
 360 #endif
 361         default:
 362                 *errp = NO_RECOVERY;
 363                 return NULL;
 364         }
 365
 366         statp = __res_state();
 367         if ((statp->options & RES_INIT) == 0) {
 368                 if (res_ninit(statp) < 0) {
 369                         RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
 370                         return NULL;
 371                 }
 372         }
 373
 374         options = statp->options;
 375         statp->options &= ~RES_USE_INET6;
 376
 377         hp = gethostbyaddr(src, len, af);
 378         if (hp == NULL)
 379                 *errp = statp->res_h_errno;
 380
 381         statp->options = options;
 382         return (_hpcopy(hp, errp));
 383 }
 384
 385 void
 386 freehostent(struct hostent *ptr)
 387 {
 388         free(ptr);
 389 }
 390
 391 /*
 392  * Private utility functions
 393  */
 394
 395 /*
 396  * _hpcopy: allocate and copy hostent structure
 397  */
 398 static struct hostent *
 399 _hpcopy(struct hostent *hp, int *errp)
 400 {
 401         struct hostent *nhp;
 402         char *cp, **pp;
 403         int size, addrsize;
 404         int nalias = 0, naddr = 0;
 405         int al_off;
 406         int i;
 407
 408         if (hp == NULL)
 409                 return hp;
 410
 411         /* count size to be allocated */
 412         size = sizeof(struct hostent);
 413         if (hp->h_name != NULL)
 414                 size += strlen(hp->h_name) + 1;
 415         if ((pp = hp->h_aliases) != NULL) {
 416                 for (i = 0; *pp != NULL; i++, pp++) {
 417                         if (**pp != '\0') {
 418                                 size += strlen(*pp) + 1;
 419                                 nalias++;
 420                         }
 421                 }
 422         }
 423         /* adjust alignment */
 424         size = ALIGN(size);
 425         al_off = size;
 426         size += sizeof(char *) * (nalias + 1);
 427         addrsize = ALIGN(hp->h_length);
 428         if ((pp = hp->h_addr_list) != NULL) {
 429                 while (*pp++ != NULL)
 430                         naddr++;
 431         }
 432         size += addrsize * naddr;
 433         size += sizeof(char *) * (naddr + 1);
 434
 435         /* copy */
 436         if ((nhp = (struct hostent *)malloc(size)) == NULL) {
 437                 *errp = TRY_AGAIN;
 438                 return NULL;
 439         }
 440         cp = (char *)&nhp[1];
 441         if (hp->h_name != NULL) {
 442                 nhp->h_name = cp;
 443                 strcpy(cp, hp->h_name);
 444                 cp += strlen(cp) + 1;
 445         } else
 446                 nhp->h_name = NULL;
 447         nhp->h_aliases = (char **)((char *)nhp + al_off);
 448         if ((pp = hp->h_aliases) != NULL) {
 449                 for (i = 0; *pp != NULL; pp++) {
 450                         if (**pp != '\0') {
 451                                 nhp->h_aliases[i++] = cp;
 452                                 strcpy(cp, *pp);
 453                                 cp += strlen(cp) + 1;
 454                         }
 455                 }
 456         }
 457         nhp->h_aliases[nalias] = NULL;
 458         cp = (char *)&nhp->h_aliases[nalias + 1];
 459         nhp->h_addrtype = hp->h_addrtype;
 460         nhp->h_length = hp->h_length;
 461         nhp->h_addr_list = (char **)cp;
 462         if ((pp = hp->h_addr_list) != NULL) {
 463                 cp = (char *)&nhp->h_addr_list[naddr + 1];
 464                 for (i = 0; *pp != NULL; pp++) {
 465                         nhp->h_addr_list[i++] = cp;
 466                         memcpy(cp, *pp, hp->h_length);
 467                         cp += addrsize;
 468                 }
 469         }
 470         nhp->h_addr_list[naddr] = NULL;
 471         return nhp;
 472 }
 473
 474 /*
 475  * _hpaddr: construct hostent structure with one address
 476  */
 477 static struct hostent *
 478 _hpaddr(int af, const char *name, void *addr, int *errp)
 479 {
 480         struct hostent *hp, hpbuf;
 481         char *addrs[2];
 482
 483         hp = &hpbuf;
 484         hp->h_name = (char *)name;
 485         hp->h_aliases = NULL;
 486         hp->h_addrtype = af;
 487         hp->h_length = ADDRLEN(af);
 488         hp->h_addr_list = addrs;
 489         addrs[0] = (char *)addr;
 490         addrs[1] = NULL;
 491         return (_hpcopy(hp, errp));
 492 }
 493
 494 #ifdef INET6
 495 /*
 496  * _hpmerge: merge 2 hostent structure, arguments will be freed
 497  */
 498 static struct hostent *
 499 _hpmerge(struct hostent *hp1, struct hostent *hp2, int *errp)
 500 {
 501         int i, j;
 502         int naddr, nalias;
 503         char **pp;
 504         struct hostent *hp, hpbuf;
 505         char *aliases[MAXALIASES + 1], *addrs[MAXADDRS + 1];
 506         union inx_addr addrbuf[MAXADDRS];
 507
 508         if (hp1 == NULL)
 509                 return _hpcopy(hp2, errp);
 510         if (hp2 == NULL)
 511                 return _hpcopy(hp1, errp);
 512
 513 #define HP(i)   (i == 1 ? hp1 : hp2)
 514         hp = &hpbuf;
 515         hp->h_name = (hp1->h_name != NULL ? hp1->h_name : hp2->h_name);
 516         hp->h_aliases = aliases;
 517         nalias = 0;
 518         for (i = 1; i <= 2; i++) {
 519                 if ((pp = HP(i)->h_aliases) == NULL)
 520                         continue;
 521                 for (; nalias < MAXALIASES && *pp != NULL; pp++) {
 522                         /* check duplicates */
 523                         for (j = 0; j < nalias; j++)
 524                                 if (strcasecmp(*pp, aliases[j]) == 0)
 525                                         break;
 526                         if (j == nalias)
 527                                 aliases[nalias++] = *pp;
 528                 }
 529         }
 530         aliases[nalias] = NULL;
 531         if (hp1->h_length != hp2->h_length) {
 532                 hp->h_addrtype = AF_INET6;
 533                 hp->h_length = sizeof(struct in6_addr);
 534         } else {
 535                 hp->h_addrtype = hp1->h_addrtype;
 536                 hp->h_length = hp1->h_length;
 537         }
 538
 539         hp->h_addr_list = addrs;
 540         naddr = 0;
 541         for (i = 1; i <= 2; i++) {
 542                 if ((pp = HP(i)->h_addr_list) == NULL)
 543                         continue;
 544                 if (HP(i)->h_length == hp->h_length) {
 545                         while (naddr < MAXADDRS && *pp != NULL)
 546                                 addrs[naddr++] = *pp++;
 547                 } else {
 548                         /* copy IPv4 addr as mapped IPv6 addr */
 549                         while (naddr < MAXADDRS && *pp != NULL) {
 550                                 MAPADDR(&addrbuf[naddr], *pp++);
 551                                 addrs[naddr] = (char *)&addrbuf[naddr];
 552                                 naddr++;
 553                         }
 554                 }
 555         }
 556         addrs[naddr] = NULL;
 557         return (_hpcopy(hp, errp));
 558 }
 559 #endif
 560
 561 /*
 562  * _hpmapv6: convert IPv4 hostent into IPv4-mapped IPv6 addresses
 563  */
 564 #ifdef INET6
 565 static struct hostent *
 566 _hpmapv6(struct hostent *hp, int *errp)
 567 {
 568         struct hostent hp6;
 569
 570         if (hp == NULL)
 571                 return NULL;
 572         if (hp->h_addrtype == AF_INET6)
 573                 return _hpcopy(hp, errp);
 574
 575         memset(&hp6, 0, sizeof(struct hostent));
 576         hp6.h_addrtype = AF_INET6;
 577         hp6.h_length = sizeof(struct in6_addr);
 578         return _hpmerge(&hp6, hp, errp);
 579 }
 580 #endif
 581
 582 /*
 583  * _hpsort: sort address by sortlist
 584  */
 585 static struct hostent *
 586 _hpsort(struct hostent *hp, res_state statp)
 587 {
 588         int i, j, n;
 589         u_char *ap, *sp, *mp, **pp;
 590         char t;
 591         char order[MAXADDRS];
 592         int nsort = statp->nsort;
 593
 594         if (hp == NULL || hp->h_addr_list[1] == NULL || nsort == 0)
 595                 return hp;
 596         for (i = 0; (ap = (u_char *)hp->h_addr_list[i]); i++) {
 597                 for (j = 0; j < nsort; j++) {
 598 #ifdef INET6
 599                         if (statp->_u._ext.ext->sort_list[j].af !=
 600                             hp->h_addrtype)
 601                                 continue;
 602                         sp = (u_char *)&statp->_u._ext.ext->sort_list[j].addr;
 603                         mp = (u_char *)&statp->_u._ext.ext->sort_list[j].mask;
 604 #else
 605                         sp = (u_char *)&statp->sort_list[j].addr;
 606                         mp = (u_char *)&statp->sort_list[j].mask;
 607 #endif
 608                         for (n = 0; n < hp->h_length; n++) {
 609                                 if ((ap[n] & mp[n]) != sp[n])
 610                                         break;
 611                         }
 612                         if (n == hp->h_length)
 613                                 break;
 614                 }
 615                 order[i] = j;
 616         }
 617         n = i;
 618         pp = (u_char **)hp->h_addr_list;
 619         for (i = 0; i < n - 1; i++) {
 620                 for (j = i + 1; j < n; j++) {
 621                         if (order[i] > order[j]) {
 622                                 ap = pp[i];
 623                                 pp[i] = pp[j];
 624                                 pp[j] = ap;
 625                                 t = order[i];
 626                                 order[i] = order[j];
 627                                 order[j] = t;
 628                         }
 629                 }
 630         }
 631         return hp;
 632 }
 633
 634 /*
 635  * _hpreorder: sort address by default address selection
 636  */
 637 static struct hostent *
 638 _hpreorder(struct hostent *hp)
 639 {
 640         struct hp_order *aio;
 641         int i, n;
 642         char *ap;
 643         struct sockaddr *sa;
 644         struct policyhead policyhead;
 645
 646         if (hp == NULL)
 647                 return hp;
 648
 649         switch (hp->h_addrtype) {
 650         case AF_INET:
 651 #ifdef INET6
 652         case AF_INET6:
 653 #endif
 654                 break;
 655         default:
 656                 free_addrselectpolicy(&policyhead);
 657                 return hp;
 658         }
 659
 660         /* count the number of addrinfo elements for sorting. */
 661         for (n = 0; hp->h_addr_list[n] != NULL; n++)
 662                 ;
 663
 664         /*
 665          * If the number is small enough, we can skip the reordering process.
 666          */
 667         if (n <= 1)
 668                 return hp;
 669
 670         /* allocate a temporary array for sort and initialization of it. */
 671         if ((aio = malloc(sizeof(*aio) * n)) == NULL)
 672                 return hp;      /* give up reordering */
 673         memset(aio, 0, sizeof(*aio) * n);
 674
 675         /* retrieve address selection policy from the kernel */
 676         TAILQ_INIT(&policyhead);
 677         if (!get_addrselectpolicy(&policyhead)) {
 678                 /* no policy is installed into kernel, we don't sort. */
 679                 free(aio);
 680                 return hp;
 681         }
 682
 683         for (i = 0; i < n; i++) {
 684                 ap = hp->h_addr_list[i];
 685                 aio[i].aio_h_addr = ap;
 686                 sa = &aio[i].aio_sa;
 687                 switch (hp->h_addrtype) {
 688                 case AF_INET:
 689                         sa->sa_family = AF_INET;
 690                         sa->sa_len = sizeof(struct sockaddr_in);
 691                         memcpy(&((struct sockaddr_in *)sa)->sin_addr, ap,
 692                             sizeof(struct in_addr));
 693                         break;
 694 #ifdef INET6
 695                 case AF_INET6:
 696                         if (IN6_IS_ADDR_V4MAPPED((struct in6_addr *)ap)) {
 697                                 sa->sa_family = AF_INET;
 698                                 sa->sa_len = sizeof(struct sockaddr_in);
 699                                 memcpy(&((struct sockaddr_in *)sa)->sin_addr,
 700                                     &ap[12], sizeof(struct in_addr));
 701                         } else {
 702                                 sa->sa_family = AF_INET6;
 703                                 sa->sa_len = sizeof(struct sockaddr_in6);
 704                                 memcpy(&((struct sockaddr_in6 *)sa)->sin6_addr,
 705                                     ap, sizeof(struct in6_addr));
 706                         }
 707                         break;
 708 #endif
 709                 }
 710                 aio[i].aio_dstscope = gai_addr2scopetype(sa);
 711                 aio[i].aio_dstpolicy = match_addrselectpolicy(sa, &policyhead);
 712                 set_source(&aio[i], &policyhead);
 713         }
 714
 715         /* perform sorting. */
 716         qsort(aio, n, sizeof(*aio), comp_dst);
 717
 718         /* reorder the h_addr_list. */
 719         for (i = 0; i < n; i++)
 720                 hp->h_addr_list[i] = aio[i].aio_h_addr;
 721
 722         /* cleanup and return */
 723         free(aio);
 724         free_addrselectpolicy(&policyhead);
 725         return hp;
 726 }
 727
 728 static int
 729 get_addrselectpolicy(struct policyhead *head)
 730 {
 731 #ifdef INET6
 732         int mib[] = { CTL_NET, PF_INET6, IPPROTO_IPV6, IPV6CTL_ADDRCTLPOLICY };
 733         size_t l;
 734         char *buf;
 735         struct in6_addrpolicy *pol, *ep;
 736
 737         if (sysctl(mib, sizeof(mib) / sizeof(mib[0]), NULL, &l, NULL, 0) < 0)
 738                 return (0);
 739         if ((buf = malloc(l)) == NULL)
 740                 return (0);
 741         if (sysctl(mib, sizeof(mib) / sizeof(mib[0]), buf, &l, NULL, 0) < 0) {
 742                 free(buf);
 743                 return (0);
 744         }
 745
 746         ep = (struct in6_addrpolicy *)(buf + l);
 747         for (pol = (struct in6_addrpolicy *)buf; pol + 1 <= ep; pol++) {
 748                 struct policyqueue *new;
 749
 750                 if ((new = malloc(sizeof(*new))) == NULL) {
 751                         free_addrselectpolicy(head); /* make the list empty */
 752                         break;
 753                 }
 754                 new->pc_policy = *pol;
 755                 TAILQ_INSERT_TAIL(head, new, pc_entry);
 756         }
 757
 758         free(buf);
 759         return (1);
 760 #else
 761         return (0);
 762 #endif
 763 }
 764
 765 static void
 766 free_addrselectpolicy(struct policyhead *head)
 767 {
 768         struct policyqueue *ent, *nent;
 769
 770         for (ent = TAILQ_FIRST(head); ent; ent = nent) {
 771                 nent = TAILQ_NEXT(ent, pc_entry);
 772                 TAILQ_REMOVE(head, ent, pc_entry);
 773                 free(ent);
 774         }
 775 }
 776
 777 static struct policyqueue *
 778 match_addrselectpolicy(struct sockaddr *addr, struct policyhead *head)
 779 {
 780 #ifdef INET6
 781         struct policyqueue *ent, *bestent = NULL;
 782         struct in6_addrpolicy *pol;
 783         int matchlen, bestmatchlen = -1;
 784         u_char *mp, *ep, *k, *p, m;
 785         struct sockaddr_in6 key;
 786
 787         switch(addr->sa_family) {
 788         case AF_INET6:
 789                 key = *(struct sockaddr_in6 *)addr;
 790                 break;
 791         case AF_INET:
 792                 /* convert the address into IPv4-mapped IPv6 address. */
 793                 memset(&key, 0, sizeof(key));
 794                 key.sin6_family = AF_INET6;
 795                 key.sin6_len = sizeof(key);
 796                 key.sin6_addr.s6_addr[10] = 0xff;
 797                 key.sin6_addr.s6_addr[11] = 0xff;
 798                 memcpy(&key.sin6_addr.s6_addr[12],
 799                        &((struct sockaddr_in *)addr)->sin_addr, 4);
 800                 break;
 801         default:
 802                 return(NULL);
 803         }
 804
 805         for (ent = TAILQ_FIRST(head); ent; ent = TAILQ_NEXT(ent, pc_entry)) {
 806                 pol = &ent->pc_policy;
 807                 matchlen = 0;
 808
 809                 mp = (u_char *)&pol->addrmask.sin6_addr;
 810                 ep = mp + 16;   /* XXX: scope field? */
 811                 k = (u_char *)&key.sin6_addr;
 812                 p = (u_char *)&pol->addr.sin6_addr;
 813                 for (; mp < ep && *mp; mp++, k++, p++) {
 814                         m = *mp;
 815                         if ((*k & m) != *p)
 816                                 goto next; /* not match */
 817                         if (m == 0xff) /* short cut for a typical case */
 818                                 matchlen += 8;
 819                         else {
 820                                 while (m >= 0x80) {
 821                                         matchlen++;
 822                                         m <<= 1;
 823                                 }
 824                         }
 825                 }
 826
 827                 /* matched.  check if this is better than the current best. */
 828                 if (matchlen > bestmatchlen) {
 829                         bestent = ent;
 830                         bestmatchlen = matchlen;
 831                 }
 832
 833           next:
 834                 continue;
 835         }
 836
 837         return(bestent);
 838 #else
 839         return(NULL);
 840 #endif
 841
 842 }
 843
 844 static void
 845 set_source(struct hp_order *aio, struct policyhead *ph)
 846 {
 847         struct sockaddr_storage ss = aio->aio_un.aiou_ss;
 848         socklen_t srclen;
 849         int s;
 850
 851         /* set unspec ("no source is available"), just in case */
 852         aio->aio_srcsa.sa_family = AF_UNSPEC;
 853         aio->aio_srcscope = -1;
 854
 855         switch(ss.ss_family) {
 856         case AF_INET:
 857                 ((struct sockaddr_in *)&ss)->sin_port = htons(1);
 858                 break;
 859 #ifdef INET6
 860         case AF_INET6:
 861                 ((struct sockaddr_in6 *)&ss)->sin6_port = htons(1);
 862                 break;
 863 #endif
 864         default:                /* ignore unsupported AFs explicitly */
 865                 return;
 866         }
 867
 868         /* open a socket to get the source address for the given dst */
 869         if ((s = _socket(ss.ss_family, SOCK_DGRAM, IPPROTO_UDP)) < 0)
 870                 return;         /* give up */
 871         if (_connect(s, (struct sockaddr *)&ss, ss.ss_len) < 0)
 872                 goto cleanup;
 873         srclen = ss.ss_len;
 874         if (_getsockname(s, &aio->aio_srcsa, &srclen) < 0) {
 875                 aio->aio_srcsa.sa_family = AF_UNSPEC;
 876                 goto cleanup;
 877         }
 878         aio->aio_srcscope = gai_addr2scopetype(&aio->aio_srcsa);
 879         aio->aio_srcpolicy = match_addrselectpolicy(&aio->aio_srcsa, ph);
 880         aio->aio_matchlen = matchlen(&aio->aio_srcsa, (struct sockaddr *)&ss);
 881 #ifdef INET6
 882         if (ss.ss_family == AF_INET6) {
 883                 struct in6_ifreq ifr6;
 884                 u_int32_t flags6;
 885
 886                 /* XXX: interface name should not be hardcoded */
 887                 strncpy(ifr6.ifr_name, "lo0", sizeof(ifr6.ifr_name));
 888                 memset(&ifr6, 0, sizeof(ifr6));
 889                 memcpy(&ifr6.ifr_addr, &ss, ss.ss_len);
 890                 if (_ioctl(s, SIOCGIFAFLAG_IN6, &ifr6) == 0) {
 891                         flags6 = ifr6.ifr_ifru.ifru_flags6;
 892                         if ((flags6 & IN6_IFF_DEPRECATED))
 893                                 aio->aio_srcflag |= AIO_SRCFLAG_DEPRECATED;
 894                 }
 895         }
 896 #endif
 897
 898   cleanup:
 899         _close(s);
 900         return;
 901 }
 902
 903 static int
 904 matchlen(struct sockaddr *src, struct sockaddr *dst)
 905 {
 906         int match = 0;
 907         u_char *s, *d;
 908         u_char *lim, r;
 909         int addrlen;
 910
 911         switch (src->sa_family) {
 912 #ifdef INET6
 913         case AF_INET6:
 914                 s = (u_char *)&((struct sockaddr_in6 *)src)->sin6_addr;
 915                 d = (u_char *)&((struct sockaddr_in6 *)dst)->sin6_addr;
 916                 addrlen = sizeof(struct in6_addr);
 917                 lim = s + addrlen;
 918                 break;
 919 #endif
 920         case AF_INET:
 921                 s = (u_char *)&((struct sockaddr_in *)src)->sin_addr;
 922                 d = (u_char *)&((struct sockaddr_in *)dst)->sin_addr;
 923                 addrlen = sizeof(struct in_addr);
 924                 lim = s + addrlen;
 925                 break;
 926         default:
 927                 return(0);
 928         }
 929
 930         while (s < lim)
 931                 if ((r = (*d++ ^ *s++)) != 0) {
 932                         while (r < addrlen * 8) {
 933                                 match++;
 934                                 r <<= 1;
 935                         }
 936                         break;
 937                 } else
 938                         match += 8;
 939         return(match);
 940 }
 941
 942 static int
 943 comp_dst(const void *arg1, const void *arg2)
 944 {
 945         const struct hp_order *dst1 = arg1, *dst2 = arg2;
 946
 947         /*
 948          * Rule 1: Avoid unusable destinations.
 949          * XXX: we currently do not consider if an appropriate route exists.
 950          */
 951         if (dst1->aio_srcsa.sa_family != AF_UNSPEC &&
 952             dst2->aio_srcsa.sa_family == AF_UNSPEC) {
 953                 return(-1);
 954         }
 955         if (dst1->aio_srcsa.sa_family == AF_UNSPEC &&
 956             dst2->aio_srcsa.sa_family != AF_UNSPEC) {
 957                 return(1);
 958         }
 959
 960         /* Rule 2: Prefer matching scope. */
 961         if (dst1->aio_dstscope == dst1->aio_srcscope &&
 962             dst2->aio_dstscope != dst2->aio_srcscope) {
 963                 return(-1);
 964         }
 965         if (dst1->aio_dstscope != dst1->aio_srcscope &&
 966             dst2->aio_dstscope == dst2->aio_srcscope) {
 967                 return(1);
 968         }
 969
 970         /* Rule 3: Avoid deprecated addresses. */
 971         if (dst1->aio_srcsa.sa_family != AF_UNSPEC &&
 972             dst2->aio_srcsa.sa_family != AF_UNSPEC) {
 973                 if (!(dst1->aio_srcflag & AIO_SRCFLAG_DEPRECATED) &&
 974                     (dst2->aio_srcflag & AIO_SRCFLAG_DEPRECATED)) {
 975                         return(-1);
 976                 }
 977                 if ((dst1->aio_srcflag & AIO_SRCFLAG_DEPRECATED) &&
 978                     !(dst2->aio_srcflag & AIO_SRCFLAG_DEPRECATED)) {
 979                         return(1);
 980                 }
 981         }
 982
 983         /* Rule 4: Prefer home addresses. */
 984         /* XXX: not implemented yet */
 985
 986         /* Rule 5: Prefer matching label. */
 987 #ifdef INET6
 988         if (dst1->aio_srcpolicy && dst1->aio_dstpolicy &&
 989             dst1->aio_srcpolicy->pc_policy.label ==
 990             dst1->aio_dstpolicy->pc_policy.label &&
 991             (dst2->aio_srcpolicy == NULL || dst2->aio_dstpolicy == NULL ||
 992              dst2->aio_srcpolicy->pc_policy.label !=
 993              dst2->aio_dstpolicy->pc_policy.label)) {
 994                 return(-1);
 995         }
 996         if (dst2->aio_srcpolicy && dst2->aio_dstpolicy &&
 997             dst2->aio_srcpolicy->pc_policy.label ==
 998             dst2->aio_dstpolicy->pc_policy.label &&
 999             (dst1->aio_srcpolicy == NULL || dst1->aio_dstpolicy == NULL ||
1000              dst1->aio_srcpolicy->pc_policy.label !=
1001              dst1->aio_dstpolicy->pc_policy.label)) {
1002                 return(1);
1003         }
1004 #endif
1005
1006         /* Rule 6: Prefer higher precedence. */
1007 #ifdef INET6
1008         if (dst1->aio_dstpolicy &&
1009             (dst2->aio_dstpolicy == NULL ||
1010              dst1->aio_dstpolicy->pc_policy.preced >
1011              dst2->aio_dstpolicy->pc_policy.preced)) {
1012                 return(-1);
1013         }
1014         if (dst2->aio_dstpolicy &&
1015             (dst1->aio_dstpolicy == NULL ||
1016              dst2->aio_dstpolicy->pc_policy.preced >
1017              dst1->aio_dstpolicy->pc_policy.preced)) {
1018                 return(1);
1019         }
1020 #endif
1021
1022         /* Rule 7: Prefer native transport. */
1023         /* XXX: not implemented yet */
1024
1025         /* Rule 8: Prefer smaller scope. */
1026         if (dst1->aio_dstscope >= 0 &&
1027             dst1->aio_dstscope < dst2->aio_dstscope) {
1028                 return(-1);
1029         }
1030         if (dst2->aio_dstscope >= 0 &&
1031             dst2->aio_dstscope < dst1->aio_dstscope) {
1032                 return(1);
1033         }
1034
1035         /*
1036          * Rule 9: Use longest matching prefix.
1037          * We compare the match length in a same AF only.
1038          */
1039         if (dst1->aio_sa.sa_family == dst2->aio_sa.sa_family) {
1040                 if (dst1->aio_matchlen > dst2->aio_matchlen) {
1041                         return(-1);
1042                 }
1043                 if (dst1->aio_matchlen < dst2->aio_matchlen) {
1044                         return(1);
1045                 }
1046         }
1047
1048         /* Rule 10: Otherwise, leave the order unchanged. */
1049         return(-1);
1050 }
1051
1052 /*
1053  * Copy from scope.c.
1054  * XXX: we should standardize the functions and link them as standard
1055  * library.
1056  */
1057 static int
1058 gai_addr2scopetype(struct sockaddr *sa)
1059 {
1060 #ifdef INET6
1061         struct sockaddr_in6 *sa6;
1062 #endif
1063         struct sockaddr_in *sa4;
1064
1065         switch(sa->sa_family) {
1066 #ifdef INET6
1067         case AF_INET6:
1068                 sa6 = (struct sockaddr_in6 *)sa;
1069                 if (IN6_IS_ADDR_MULTICAST(&sa6->sin6_addr)) {
1070                         /* just use the scope field of the multicast address */
1071                         return(sa6->sin6_addr.s6_addr[2] & 0x0f);
1072                 }
1073                 /*
1074                  * Unicast addresses: map scope type to corresponding scope
1075                  * value defined for multcast addresses.
1076                  * XXX: hardcoded scope type values are bad...
1077                  */
1078                 if (IN6_IS_ADDR_LOOPBACK(&sa6->sin6_addr))
1079                         return(1); /* node local scope */
1080                 if (IN6_IS_ADDR_LINKLOCAL(&sa6->sin6_addr))
1081                         return(2); /* link-local scope */
1082                 if (IN6_IS_ADDR_SITELOCAL(&sa6->sin6_addr))
1083                         return(5); /* site-local scope */
1084                 return(14);     /* global scope */
1085                 break;
1086 #endif
1087         case AF_INET:
1088                 /*
1089                  * IPv4 pseudo scoping according to RFC 3484.
1090                  */
1091                 sa4 = (struct sockaddr_in *)sa;
1092                 /* IPv4 autoconfiguration addresses have link-local scope. */
1093                 if (((u_char *)&sa4->sin_addr)[0] == 169 &&
1094                     ((u_char *)&sa4->sin_addr)[1] == 254)
1095                         return(2);
1096                 /* Private addresses have site-local scope. */
1097                 if (((u_char *)&sa4->sin_addr)[0] == 10 ||
1098                     (((u_char *)&sa4->sin_addr)[0] == 172 &&
1099                      (((u_char *)&sa4->sin_addr)[1] & 0xf0) == 16) ||
1100                     (((u_char *)&sa4->sin_addr)[0] == 192 &&
1101                      ((u_char *)&sa4->sin_addr)[1] == 168))
1102                         return(14);     /* XXX: It should be 5 unless NAT */
1103                 /* Loopback addresses have link-local scope. */
1104                 if (((u_char *)&sa4->sin_addr)[0] == 127)
1105                         return(2);
1106                 return(14);
1107                 break;
1108         default:
1109                 errno = EAFNOSUPPORT; /* is this a good error? */
1110                 return(-1);
1111         }
1112 }