1 /* $KAME: name6.c,v 1.25 2000/06/26 16:44:40 itojun Exp $ */
2
3 /*-
4 * SPDX-License-Identifier: BSD-3-Clause
5 *
6 * Copyright (C) 1995, 1996, 1997, 1998, and 1999 WIDE Project.
7 * All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 3. Neither the name of the project nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33 /*
34 * ++Copyright++ 1985, 1988, 1993
35 * -
36 * Copyright (c) 1985, 1988, 1993
37 * The Regents of the University of California. All rights reserved.
38 *
39 * Redistribution and use in source and binary forms, with or without
40 * modification, are permitted provided that the following conditions
41 * are met:
42 * 1. Redistributions of source code must retain the above copyright
43 * notice, this list of conditions and the following disclaimer.
44 * 2. Redistributions in binary form must reproduce the above copyright
45 * notice, this list of conditions and the following disclaimer in the
46 * documentation and/or other materials provided with the distribution.
47 * 3. Neither the name of the University nor the names of its contributors
48 * may be used to endorse or promote products derived from this software
49 * without specific prior written permission.
50 *
51 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
52 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
53 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
54 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
55 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
56 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
57 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
58 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
59 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
60 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
61 * SUCH DAMAGE.
62 * -
63 * Portions Copyright (c) 1993 by Digital Equipment Corporation.
64 *
65 * Permission to use, copy, modify, and distribute this software for any
66 * purpose with or without fee is hereby granted, provided that the above
67 * copyright notice and this permission notice appear in all copies, and that
68 * the name of Digital Equipment Corporation not be used in advertising or
69 * publicity pertaining to distribution of the document or software without
70 * specific, written prior permission.
71 *
72 * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
73 * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
74 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT
75 * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
76 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
77 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
78 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
79 * SOFTWARE.
80 * -
81 * --Copyright--
82 */
83
84 /*
85 * Atsushi Onoe <onoe@sm.sony.co.jp>
86 */
87
88 #include "namespace.h"
89 #include <sys/param.h>
90 #include <sys/socket.h>
91 #include <sys/time.h>
92 #include <sys/queue.h>
93 #include <netinet/in.h>
94 #ifdef INET6
95 #include <net/if.h>
96 #include <sys/sysctl.h>
97 #include <sys/ioctl.h>
98 #include <netinet6/in6_var.h> /* XXX */
99 #endif
100
101 #include <arpa/inet.h>
102 #include <arpa/nameser.h>
103
104 #include <errno.h>
105 #include <netdb.h>
106 #include <resolv.h>
107 #include <stdio.h>
108 #include <stdlib.h>
109 #include <string.h>
110 #include <stdarg.h>
111 #include <nsswitch.h>
112 #include <unistd.h>
113 #include "un-namespace.h"
114 #include "netdb_private.h"
115 #include "res_private.h"
116
117 #ifndef MAXALIASES
118 #define MAXALIASES 10
119 #endif
120 #ifndef MAXADDRS
121 #define MAXADDRS 20
122 #endif
123 #ifndef MAXDNAME
124 #define MAXDNAME 1025
125 #endif
126
127 #ifdef INET6
128 #define ADDRLEN(af) ((af) == AF_INET6 ? sizeof(struct in6_addr) : \
129 sizeof(struct in_addr))
130 #else
131 #define ADDRLEN(af) sizeof(struct in_addr)
132 #endif
133
134 #define MAPADDR(ab, ina) \
135 do { \
136 memcpy(&(ab)->map_inaddr, ina, sizeof(struct in_addr)); \
137 memset((ab)->map_zero, 0, sizeof((ab)->map_zero)); \
138 memset((ab)->map_one, 0xff, sizeof((ab)->map_one)); \
139 } while (0)
140 #define MAPADDRENABLED(flags) \
141 (((flags) & AI_V4MAPPED) || \
142 (((flags) & AI_V4MAPPED_CFG)))
143
144 union inx_addr {
145 struct in_addr in_addr;
146 #ifdef INET6
147 struct in6_addr in6_addr;
148 #endif
149 struct {
150 u_char mau_zero[10];
151 u_char mau_one[2];
152 struct in_addr mau_inaddr;
153 } map_addr_un;
154 #define map_zero map_addr_un.mau_zero
155 #define map_one map_addr_un.mau_one
156 #define map_inaddr map_addr_un.mau_inaddr
157 };
158
159 struct policyqueue {
160 TAILQ_ENTRY(policyqueue) pc_entry;
161 #ifdef INET6
162 struct in6_addrpolicy pc_policy;
163 #endif
164 };
165 TAILQ_HEAD(policyhead, policyqueue);
166
167 #define AIO_SRCFLAG_DEPRECATED 0x1
168
169 struct hp_order {
170 union {
171 struct sockaddr_storage aiou_ss;
172 struct sockaddr aiou_sa;
173 } aio_src_un;
174 #define aio_srcsa aio_src_un.aiou_sa
175 u_int32_t aio_srcflag;
176 int aio_srcscope;
177 int aio_dstscope;
178 struct policyqueue *aio_srcpolicy;
179 struct policyqueue *aio_dstpolicy;
180 union {
181 struct sockaddr_storage aiou_ss;
182 struct sockaddr aiou_sa;
183 } aio_un;
184 #define aio_sa aio_un.aiou_sa
185 int aio_matchlen;
186 char *aio_h_addr;
187 int aio_initial_sequence;
188 };
189
190 static struct hostent *_hpcopy(struct hostent *, int *);
191 static struct hostent *_hpaddr(int, const char *, void *, int *);
192 #ifdef INET6
193 static struct hostent *_hpmerge(struct hostent *, struct hostent *, int *);
194 static struct hostent *_hpmapv6(struct hostent *, int *);
195 #endif
196 static struct hostent *_hpsort(struct hostent *, res_state);
197
198 #ifdef INET6
199 static struct hostent *_hpreorder(struct hostent *);
200 static int get_addrselectpolicy(struct policyhead *);
201 static void free_addrselectpolicy(struct policyhead *);
202 static struct policyqueue *match_addrselectpolicy(struct sockaddr *,
203 struct policyhead *);
204 static void set_source(struct hp_order *, struct policyhead *);
205 static int matchlen(struct sockaddr *, struct sockaddr *);
206 static int comp_dst(const void *, const void *);
207 static int gai_addr2scopetype(struct sockaddr *);
208 #endif
209
210 /*
211 * Functions defined in RFC2553
212 * getipnodebyname, getipnodebyaddr, freehostent
213 */
214
215 struct hostent *
getipnodebyname(const char * name,int af,int flags,int * errp)216 getipnodebyname(const char *name, int af, int flags, int *errp)
217 {
218 struct hostent *hp;
219 union inx_addr addrbuf;
220 res_state statp;
221 u_long options;
222
223 switch (af) {
224 case AF_INET:
225 #ifdef INET6
226 case AF_INET6:
227 #endif
228 break;
229 default:
230 *errp = NO_RECOVERY;
231 return NULL;
232 }
233
234 if (flags & AI_ADDRCONFIG) {
235 int s;
236
237 if ((s = _socket(af, SOCK_DGRAM | SOCK_CLOEXEC, 0)) < 0)
238 return NULL;
239 /*
240 * TODO:
241 * Note that implementation dependent test for address
242 * configuration should be done every time called
243 * (or appropriate interval),
244 * because addresses will be dynamically assigned or deleted.
245 */
246 _close(s);
247 }
248
249 #ifdef INET6
250 /* special case for literal address */
251 if (inet_pton(AF_INET6, name, &addrbuf) == 1) {
252 if (af != AF_INET6) {
253 *errp = HOST_NOT_FOUND;
254 return NULL;
255 }
256 return _hpaddr(af, name, &addrbuf, errp);
257 }
258 #endif
259 if (inet_aton(name, (struct in_addr *)&addrbuf) == 1) {
260 if (af != AF_INET) {
261 if (MAPADDRENABLED(flags)) {
262 MAPADDR(&addrbuf, &addrbuf.in_addr);
263 } else {
264 *errp = HOST_NOT_FOUND;
265 return NULL;
266 }
267 }
268 return _hpaddr(af, name, &addrbuf, errp);
269 }
270
271
272 statp = __res_state();
273 if ((statp->options & RES_INIT) == 0) {
274 if (res_ninit(statp) < 0) {
275 *errp = NETDB_INTERNAL;
276 return NULL;
277 }
278 }
279
280 options = statp->options;
281 statp->options &= ~RES_USE_INET6;
282
283 hp = gethostbyname2(name, af);
284 hp = _hpcopy(hp, errp);
285 #ifdef INET6
286 if (af == AF_INET6)
287 hp = _hpreorder(hp);
288
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 _hpsort(hp, statp);
312 }
313
314 struct hostent *
getipnodebyaddr(const void * src,size_t len,int af,int * errp)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 (rounddown2((long)src, sizeof(struct in_addr))) {
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 (rounddown2((long)src, sizeof(struct in6_addr) / 2)) {
347 /* XXX */
348 memcpy(&addrbuf, src, len);
349 src = &addrbuf;
350 }
351 if (IN6_IS_ADDR_UNSPECIFIED((struct in6_addr *)src))
352 return NULL;
353 if (IN6_IS_ADDR_V4MAPPED((struct in6_addr *)src)
354 || IN6_IS_ADDR_V4COMPAT((struct in6_addr *)src)) {
355 src = (char *)src +
356 (sizeof(struct in6_addr) - sizeof(struct in_addr));
357 af = AF_INET;
358 len = sizeof(struct in_addr);
359 }
360 break;
361 #endif
362 default:
363 *errp = NO_RECOVERY;
364 return NULL;
365 }
366
367 statp = __res_state();
368 if ((statp->options & RES_INIT) == 0) {
369 if (res_ninit(statp) < 0) {
370 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
371 return NULL;
372 }
373 }
374
375 options = statp->options;
376 statp->options &= ~RES_USE_INET6;
377
378 hp = gethostbyaddr(src, len, af);
379 if (hp == NULL)
380 *errp = statp->res_h_errno;
381
382 statp->options = options;
383 return (_hpcopy(hp, errp));
384 }
385
386 void
freehostent(struct hostent * ptr)387 freehostent(struct hostent *ptr)
388 {
389 free(ptr);
390 }
391
392 /*
393 * Private utility functions
394 */
395
396 /*
397 * _hpcopy: allocate and copy hostent structure
398 */
399 static struct hostent *
_hpcopy(struct hostent * hp,int * errp)400 _hpcopy(struct hostent *hp, int *errp)
401 {
402 struct hostent *nhp;
403 char *cp, **pp;
404 int size, addrsize;
405 int nalias = 0, naddr = 0;
406 int al_off;
407 int i;
408
409 if (hp == NULL)
410 return hp;
411
412 /* count size to be allocated */
413 size = sizeof(struct hostent);
414 if (hp->h_name != NULL)
415 size += strlen(hp->h_name) + 1;
416 if ((pp = hp->h_aliases) != NULL) {
417 for (i = 0; *pp != NULL; i++, pp++) {
418 if (**pp != '\0') {
419 size += strlen(*pp) + 1;
420 nalias++;
421 }
422 }
423 }
424 /* adjust alignment */
425 size = ALIGN(size);
426 al_off = size;
427 size += sizeof(char *) * (nalias + 1);
428 addrsize = ALIGN(hp->h_length);
429 if ((pp = hp->h_addr_list) != NULL) {
430 while (*pp++ != NULL)
431 naddr++;
432 }
433 size += addrsize * naddr;
434 size += sizeof(char *) * (naddr + 1);
435
436 /* copy */
437 if ((nhp = (struct hostent *)malloc(size)) == NULL) {
438 *errp = TRY_AGAIN;
439 return NULL;
440 }
441 cp = (char *)&nhp[1];
442 if (hp->h_name != NULL) {
443 nhp->h_name = cp;
444 strcpy(cp, hp->h_name);
445 cp += strlen(cp) + 1;
446 } else
447 nhp->h_name = NULL;
448 nhp->h_aliases = (char **)((char *)nhp + al_off);
449 if ((pp = hp->h_aliases) != NULL) {
450 for (i = 0; *pp != NULL; pp++) {
451 if (**pp != '\0') {
452 nhp->h_aliases[i++] = cp;
453 strcpy(cp, *pp);
454 cp += strlen(cp) + 1;
455 }
456 }
457 }
458 nhp->h_aliases[nalias] = NULL;
459 cp = (char *)&nhp->h_aliases[nalias + 1];
460 nhp->h_addrtype = hp->h_addrtype;
461 nhp->h_length = hp->h_length;
462 nhp->h_addr_list = (char **)cp;
463 if ((pp = hp->h_addr_list) != NULL) {
464 cp = (char *)&nhp->h_addr_list[naddr + 1];
465 for (i = 0; *pp != NULL; pp++) {
466 nhp->h_addr_list[i++] = cp;
467 memcpy(cp, *pp, hp->h_length);
468 cp += addrsize;
469 }
470 }
471 nhp->h_addr_list[naddr] = NULL;
472 return nhp;
473 }
474
475 /*
476 * _hpaddr: construct hostent structure with one address
477 */
478 static struct hostent *
_hpaddr(int af,const char * name,void * addr,int * errp)479 _hpaddr(int af, const char *name, void *addr, int *errp)
480 {
481 struct hostent *hp, hpbuf;
482 char *addrs[2];
483
484 hp = &hpbuf;
485 hp->h_name = (char *)name;
486 hp->h_aliases = NULL;
487 hp->h_addrtype = af;
488 hp->h_length = ADDRLEN(af);
489 hp->h_addr_list = addrs;
490 addrs[0] = (char *)addr;
491 addrs[1] = NULL;
492 return (_hpcopy(hp, errp));
493 }
494
495 #ifdef INET6
496 /*
497 * _hpmerge: merge 2 hostent structure, arguments will be freed
498 */
499 static struct hostent *
_hpmerge(struct hostent * hp1,struct hostent * hp2,int * errp)500 _hpmerge(struct hostent *hp1, struct hostent *hp2, int *errp)
501 {
502 int i, j;
503 int naddr, nalias;
504 char **pp;
505 struct hostent *hp, hpbuf;
506 char *aliases[MAXALIASES + 1], *addrs[MAXADDRS + 1];
507 union inx_addr addrbuf[MAXADDRS];
508
509 if (hp1 == NULL)
510 return _hpcopy(hp2, errp);
511 if (hp2 == NULL)
512 return _hpcopy(hp1, errp);
513
514 #define HP(i) (i == 1 ? hp1 : hp2)
515 hp = &hpbuf;
516 hp->h_name = (hp1->h_name != NULL ? hp1->h_name : hp2->h_name);
517 hp->h_aliases = aliases;
518 nalias = 0;
519 for (i = 1; i <= 2; i++) {
520 if ((pp = HP(i)->h_aliases) == NULL)
521 continue;
522 for (; nalias < MAXALIASES && *pp != NULL; pp++) {
523 /* check duplicates */
524 for (j = 0; j < nalias; j++)
525 if (strcasecmp(*pp, aliases[j]) == 0)
526 break;
527 if (j == nalias)
528 aliases[nalias++] = *pp;
529 }
530 }
531 aliases[nalias] = NULL;
532 if (hp1->h_length != hp2->h_length) {
533 hp->h_addrtype = AF_INET6;
534 hp->h_length = sizeof(struct in6_addr);
535 } else {
536 hp->h_addrtype = hp1->h_addrtype;
537 hp->h_length = hp1->h_length;
538 }
539
540 hp->h_addr_list = addrs;
541 naddr = 0;
542 for (i = 1; i <= 2; i++) {
543 if ((pp = HP(i)->h_addr_list) == NULL)
544 continue;
545 if (HP(i)->h_length == hp->h_length) {
546 while (naddr < MAXADDRS && *pp != NULL)
547 addrs[naddr++] = *pp++;
548 } else {
549 /* copy IPv4 addr as mapped IPv6 addr */
550 while (naddr < MAXADDRS && *pp != NULL) {
551 MAPADDR(&addrbuf[naddr], *pp++);
552 addrs[naddr] = (char *)&addrbuf[naddr];
553 naddr++;
554 }
555 }
556 }
557 addrs[naddr] = NULL;
558 return (_hpcopy(hp, errp));
559 }
560 #endif
561
562 /*
563 * _hpmapv6: convert IPv4 hostent into IPv4-mapped IPv6 addresses
564 */
565 #ifdef INET6
566 static struct hostent *
_hpmapv6(struct hostent * hp,int * errp)567 _hpmapv6(struct hostent *hp, int *errp)
568 {
569 struct hostent hp6;
570
571 if (hp == NULL)
572 return NULL;
573 if (hp->h_addrtype == AF_INET6)
574 return _hpcopy(hp, errp);
575
576 memset(&hp6, 0, sizeof(struct hostent));
577 hp6.h_addrtype = AF_INET6;
578 hp6.h_length = sizeof(struct in6_addr);
579 return _hpmerge(&hp6, hp, errp);
580 }
581 #endif
582
583 /*
584 * _hpsort: sort address by sortlist
585 */
586 static struct hostent *
_hpsort(struct hostent * hp,res_state statp)587 _hpsort(struct hostent *hp, res_state statp)
588 {
589 int i, j, n;
590 u_char *ap, *sp, *mp, **pp;
591 char t;
592 char order[MAXADDRS];
593 int nsort = statp->nsort;
594
595 if (hp == NULL || hp->h_addr_list[1] == NULL || nsort == 0)
596 return hp;
597 for (i = 0; (ap = (u_char *)hp->h_addr_list[i]); i++) {
598 for (j = 0; j < nsort; j++) {
599 #ifdef INET6
600 if (statp->_u._ext.ext->sort_list[j].af !=
601 hp->h_addrtype)
602 continue;
603 sp = (u_char *)&statp->_u._ext.ext->sort_list[j].addr;
604 mp = (u_char *)&statp->_u._ext.ext->sort_list[j].mask;
605 #else
606 sp = (u_char *)&statp->sort_list[j].addr;
607 mp = (u_char *)&statp->sort_list[j].mask;
608 #endif
609 for (n = 0; n < hp->h_length; n++) {
610 if ((ap[n] & mp[n]) != sp[n])
611 break;
612 }
613 if (n == hp->h_length)
614 break;
615 }
616 order[i] = j;
617 }
618 n = i;
619 pp = (u_char **)hp->h_addr_list;
620 for (i = 0; i < n - 1; i++) {
621 for (j = i + 1; j < n; j++) {
622 if (order[i] > order[j]) {
623 ap = pp[i];
624 pp[i] = pp[j];
625 pp[j] = ap;
626 t = order[i];
627 order[i] = order[j];
628 order[j] = t;
629 }
630 }
631 }
632 return hp;
633 }
634
635 #ifdef INET6
636 /*
637 * _hpreorder: sort address by default address selection
638 */
639 static struct hostent *
_hpreorder(struct hostent * hp)640 _hpreorder(struct hostent *hp)
641 {
642 struct hp_order *aio;
643 int i, n;
644 char *ap;
645 struct sockaddr *sa;
646 struct policyhead policyhead;
647
648 if (hp == NULL)
649 return hp;
650
651 switch (hp->h_addrtype) {
652 case AF_INET:
653 #ifdef INET6
654 case AF_INET6:
655 #endif
656 break;
657 default:
658 return hp;
659 }
660
661 /* count the number of addrinfo elements for sorting. */
662 for (n = 0; hp->h_addr_list[n] != NULL; n++)
663 ;
664
665 /*
666 * If the number is small enough, we can skip the reordering process.
667 */
668 if (n <= 1)
669 return hp;
670
671 /* allocate a temporary array for sort and initialization of it. */
672 if ((aio = malloc(sizeof(*aio) * n)) == NULL)
673 return hp; /* give up reordering */
674 memset(aio, 0, sizeof(*aio) * n);
675
676 /* retrieve address selection policy from the kernel */
677 TAILQ_INIT(&policyhead);
678 if (!get_addrselectpolicy(&policyhead)) {
679 /* no policy is installed into kernel, we don't sort. */
680 free(aio);
681 return hp;
682 }
683
684 for (i = 0; i < n; i++) {
685 ap = hp->h_addr_list[i];
686 aio[i].aio_h_addr = ap;
687 sa = &aio[i].aio_sa;
688 switch (hp->h_addrtype) {
689 case AF_INET:
690 sa->sa_family = AF_INET;
691 sa->sa_len = sizeof(struct sockaddr_in);
692 memcpy(&((struct sockaddr_in *)sa)->sin_addr, ap,
693 sizeof(struct in_addr));
694 break;
695 #ifdef INET6
696 case AF_INET6:
697 if (IN6_IS_ADDR_V4MAPPED((struct in6_addr *)ap)) {
698 sa->sa_family = AF_INET;
699 sa->sa_len = sizeof(struct sockaddr_in);
700 memcpy(&((struct sockaddr_in *)sa)->sin_addr,
701 &ap[12], sizeof(struct in_addr));
702 } else {
703 sa->sa_family = AF_INET6;
704 sa->sa_len = sizeof(struct sockaddr_in6);
705 memcpy(&((struct sockaddr_in6 *)sa)->sin6_addr,
706 ap, sizeof(struct in6_addr));
707 }
708 break;
709 #endif
710 }
711 aio[i].aio_dstscope = gai_addr2scopetype(sa);
712 aio[i].aio_dstpolicy = match_addrselectpolicy(sa, &policyhead);
713 set_source(&aio[i], &policyhead);
714 aio[i].aio_initial_sequence = i;
715 }
716
717 /* perform sorting. */
718 qsort(aio, n, sizeof(*aio), comp_dst);
719
720 /* reorder the h_addr_list. */
721 for (i = 0; i < n; i++)
722 hp->h_addr_list[i] = aio[i].aio_h_addr;
723
724 /* cleanup and return */
725 free(aio);
726 free_addrselectpolicy(&policyhead);
727 return hp;
728 }
729
730 static int
get_addrselectpolicy(struct policyhead * head)731 get_addrselectpolicy(struct policyhead *head)
732 {
733 #ifdef INET6
734 int mib[] = { CTL_NET, PF_INET6, IPPROTO_IPV6, IPV6CTL_ADDRCTLPOLICY };
735 size_t l;
736 char *buf;
737 struct in6_addrpolicy *pol, *ep;
738
739 if (sysctl(mib, nitems(mib), NULL, &l, NULL, 0) < 0)
740 return (0);
741 if ((buf = malloc(l)) == NULL)
742 return (0);
743 if (sysctl(mib, nitems(mib), buf, &l, NULL, 0) < 0) {
744 free(buf);
745 return (0);
746 }
747
748 ep = (struct in6_addrpolicy *)(buf + l);
749 for (pol = (struct in6_addrpolicy *)buf; pol + 1 <= ep; pol++) {
750 struct policyqueue *new;
751
752 if ((new = malloc(sizeof(*new))) == NULL) {
753 free_addrselectpolicy(head); /* make the list empty */
754 break;
755 }
756 new->pc_policy = *pol;
757 TAILQ_INSERT_TAIL(head, new, pc_entry);
758 }
759
760 free(buf);
761 return (1);
762 #else
763 return (0);
764 #endif
765 }
766
767 static void
free_addrselectpolicy(struct policyhead * head)768 free_addrselectpolicy(struct policyhead *head)
769 {
770 struct policyqueue *ent, *nent;
771
772 for (ent = TAILQ_FIRST(head); ent; ent = nent) {
773 nent = TAILQ_NEXT(ent, pc_entry);
774 TAILQ_REMOVE(head, ent, pc_entry);
775 free(ent);
776 }
777 }
778
779 static struct policyqueue *
match_addrselectpolicy(struct sockaddr * addr,struct policyhead * head)780 match_addrselectpolicy(struct sockaddr *addr, struct policyhead *head)
781 {
782 #ifdef INET6
783 struct policyqueue *ent, *bestent = NULL;
784 struct in6_addrpolicy *pol;
785 int matchlen, bestmatchlen = -1;
786 u_char *mp, *ep, *k, *p, m;
787 struct sockaddr_in6 key;
788
789 switch(addr->sa_family) {
790 case AF_INET6:
791 key = *(struct sockaddr_in6 *)addr;
792 break;
793 case AF_INET:
794 /* convert the address into IPv4-mapped IPv6 address. */
795 memset(&key, 0, sizeof(key));
796 key.sin6_family = AF_INET6;
797 key.sin6_len = sizeof(key);
798 _map_v4v6_address(
799 (char *)&((struct sockaddr_in *)addr)->sin_addr,
800 (char *)&key.sin6_addr);
801 break;
802 default:
803 return(NULL);
804 }
805
806 for (ent = TAILQ_FIRST(head); ent; ent = TAILQ_NEXT(ent, pc_entry)) {
807 pol = &ent->pc_policy;
808 matchlen = 0;
809
810 mp = (u_char *)&pol->addrmask.sin6_addr;
811 ep = mp + 16; /* XXX: scope field? */
812 k = (u_char *)&key.sin6_addr;
813 p = (u_char *)&pol->addr.sin6_addr;
814 for (; mp < ep && *mp; mp++, k++, p++) {
815 m = *mp;
816 if ((*k & m) != *p)
817 goto next; /* not match */
818 if (m == 0xff) /* short cut for a typical case */
819 matchlen += 8;
820 else {
821 while (m >= 0x80) {
822 matchlen++;
823 m <<= 1;
824 }
825 }
826 }
827
828 /* matched. check if this is better than the current best. */
829 if (matchlen > bestmatchlen) {
830 bestent = ent;
831 bestmatchlen = matchlen;
832 }
833
834 next:
835 continue;
836 }
837
838 return(bestent);
839 #else
840 return(NULL);
841 #endif
842
843 }
844
845 static void
set_source(struct hp_order * aio,struct policyhead * ph)846 set_source(struct hp_order *aio, struct policyhead *ph)
847 {
848 struct sockaddr_storage ss = aio->aio_un.aiou_ss;
849 socklen_t srclen;
850 int s;
851
852 /* set unspec ("no source is available"), just in case */
853 aio->aio_srcsa.sa_family = AF_UNSPEC;
854 aio->aio_srcscope = -1;
855
856 switch(ss.ss_family) {
857 case AF_INET:
858 ((struct sockaddr_in *)&ss)->sin_port = htons(1);
859 break;
860 #ifdef INET6
861 case AF_INET6:
862 ((struct sockaddr_in6 *)&ss)->sin6_port = htons(1);
863 break;
864 #endif
865 default: /* ignore unsupported AFs explicitly */
866 return;
867 }
868
869 /* open a socket to get the source address for the given dst */
870 if ((s = _socket(ss.ss_family, SOCK_DGRAM | SOCK_CLOEXEC,
871 IPPROTO_UDP)) < 0)
872 return; /* give up */
873 if (_connect(s, (struct sockaddr *)&ss, ss.ss_len) < 0)
874 goto cleanup;
875 srclen = ss.ss_len;
876 if (_getsockname(s, &aio->aio_srcsa, &srclen) < 0) {
877 aio->aio_srcsa.sa_family = AF_UNSPEC;
878 goto cleanup;
879 }
880 aio->aio_srcscope = gai_addr2scopetype(&aio->aio_srcsa);
881 aio->aio_srcpolicy = match_addrselectpolicy(&aio->aio_srcsa, ph);
882 aio->aio_matchlen = matchlen(&aio->aio_srcsa, (struct sockaddr *)&ss);
883 #ifdef INET6
884 if (ss.ss_family == AF_INET6) {
885 struct in6_ifreq ifr6;
886 u_int32_t flags6;
887
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
matchlen(struct sockaddr * src,struct sockaddr * dst)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 & 0x80) == 0) {
933 match++;
934 r <<= 1;
935 }
936 break;
937 } else
938 match += 8;
939 return(match);
940 }
941
942 static int
comp_dst(const void * arg1,const void * arg2)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
1050 /*
1051 * Note that qsort is unstable; so, we can't return zero and
1052 * expect the order to be unchanged.
1053 * That also means we can't depend on the current position of
1054 * dst2 being after dst1. We must enforce the initial order
1055 * with an explicit compare on the original position.
1056 * The qsort specification requires that "When the same objects
1057 * (consisting of width bytes, irrespective of their current
1058 * positions in the array) are passed more than once to the
1059 * comparison function, the results shall be consistent with one
1060 * another."
1061 * In other words, If A < B, then we must also return B > A.
1062 */
1063 if (dst2->aio_initial_sequence < dst1->aio_initial_sequence)
1064 return(1);
1065
1066 return(-1);
1067 }
1068
1069 /*
1070 * Copy from scope.c.
1071 * XXX: we should standardize the functions and link them as standard
1072 * library.
1073 */
1074 static int
gai_addr2scopetype(struct sockaddr * sa)1075 gai_addr2scopetype(struct sockaddr *sa)
1076 {
1077 #ifdef INET6
1078 struct sockaddr_in6 *sa6;
1079 #endif
1080 struct sockaddr_in *sa4;
1081
1082 switch(sa->sa_family) {
1083 #ifdef INET6
1084 case AF_INET6:
1085 sa6 = (struct sockaddr_in6 *)sa;
1086 if (IN6_IS_ADDR_MULTICAST(&sa6->sin6_addr)) {
1087 /* just use the scope field of the multicast address */
1088 return(sa6->sin6_addr.s6_addr[2] & 0x0f);
1089 }
1090 /*
1091 * Unicast addresses: map scope type to corresponding scope
1092 * value defined for multcast addresses.
1093 * XXX: hardcoded scope type values are bad...
1094 */
1095 if (IN6_IS_ADDR_LOOPBACK(&sa6->sin6_addr))
1096 return(1); /* node local scope */
1097 if (IN6_IS_ADDR_LINKLOCAL(&sa6->sin6_addr))
1098 return(2); /* link-local scope */
1099 if (IN6_IS_ADDR_SITELOCAL(&sa6->sin6_addr))
1100 return(5); /* site-local scope */
1101 return(14); /* global scope */
1102 break;
1103 #endif
1104 case AF_INET:
1105 /*
1106 * IPv4 pseudo scoping according to RFC 3484.
1107 */
1108 sa4 = (struct sockaddr_in *)sa;
1109 /* IPv4 autoconfiguration addresses have link-local scope. */
1110 if (((u_char *)&sa4->sin_addr)[0] == 169 &&
1111 ((u_char *)&sa4->sin_addr)[1] == 254)
1112 return(2);
1113 /* Private addresses have site-local scope. */
1114 if (((u_char *)&sa4->sin_addr)[0] == 10 ||
1115 (((u_char *)&sa4->sin_addr)[0] == 172 &&
1116 (((u_char *)&sa4->sin_addr)[1] & 0xf0) == 16) ||
1117 (((u_char *)&sa4->sin_addr)[0] == 192 &&
1118 ((u_char *)&sa4->sin_addr)[1] == 168))
1119 return(14); /* XXX: It should be 5 unless NAT */
1120 /* Loopback addresses have link-local scope. */
1121 if (((u_char *)&sa4->sin_addr)[0] == 127)
1122 return(2);
1123 return(14);
1124 break;
1125 default:
1126 errno = EAFNOSUPPORT; /* is this a good error? */
1127 return(-1);
1128 }
1129 }
1130 #endif
1131