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. Neither the name of the University nor the names of its contributors
46 * may be used to endorse or promote products derived from this software
47 * without specific prior written permission.
48 *
49 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
50 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
51 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
52 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
53 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
54 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
55 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
56 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
57 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
58 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
59 * SUCH DAMAGE.
60 * -
61 * Portions Copyright (c) 1993 by Digital Equipment Corporation.
62 *
63 * Permission to use, copy, modify, and distribute this software for any
64 * purpose with or without fee is hereby granted, provided that the above
65 * copyright notice and this permission notice appear in all copies, and that
66 * the name of Digital Equipment Corporation not be used in advertising or
67 * publicity pertaining to distribution of the document or software without
68 * specific, written prior permission.
69 *
70 * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
71 * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
72 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT
73 * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
74 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
75 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
76 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
77 * SOFTWARE.
78 * -
79 * --Copyright--
80 *
81 * $FreeBSD: src/lib/libc/net/name6.c,v 1.62 2007/07/31 16:09:41 bushman Exp $
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 <net/if_var.h>
97 #include <sys/sysctl.h>
98 #include <sys/ioctl.h>
99 #include <netinet6/in6_var.h> /* XXX */
100 #endif
101
102 #include <arpa/inet.h>
103 #include <arpa/nameser.h>
104
105 #include <errno.h>
106 #include <netdb.h>
107 #include <resolv.h>
108 #include <stdio.h>
109 #include <stdlib.h>
110 #include <string.h>
111 #include <stdarg.h>
112 #include <nsswitch.h>
113 #include <unistd.h>
114 #include "un-namespace.h"
115 #include "netdb_private.h"
116 #include "res_private.h"
117
118 #ifndef MAXALIASES
119 #define MAXALIASES 10
120 #endif
121 #ifndef MAXADDRS
122 #define MAXADDRS 20
123 #endif
124 #ifndef MAXDNAME
125 #define MAXDNAME 1025
126 #endif
127
128 #ifdef INET6
129 #define ADDRLEN(af) ((af) == AF_INET6 ? sizeof(struct in6_addr) : \
130 sizeof(struct in_addr))
131 #else
132 #define ADDRLEN(af) sizeof(struct in_addr)
133 #endif
134
135 #define MAPADDR(ab, ina) \
136 do { \
137 memcpy(&(ab)->map_inaddr, ina, sizeof(struct in_addr)); \
138 memset((ab)->map_zero, 0, sizeof((ab)->map_zero)); \
139 memset((ab)->map_one, 0xff, sizeof((ab)->map_one)); \
140 } while (0)
141 #define MAPADDRENABLED(flags) \
142 (((flags) & AI_V4MAPPED) || \
143 (((flags) & AI_V4MAPPED_CFG)))
144
145 union inx_addr {
146 struct in_addr in_addr;
147 #ifdef INET6
148 struct in6_addr in6_addr;
149 #endif
150 struct {
151 u_char mau_zero[10];
152 u_char mau_one[2];
153 struct in_addr mau_inaddr;
154 } map_addr_un;
155 #define map_zero map_addr_un.mau_zero
156 #define map_one map_addr_un.mau_one
157 #define map_inaddr map_addr_un.mau_inaddr
158 };
159
160 struct policyqueue {
161 TAILQ_ENTRY(policyqueue) pc_entry;
162 #ifdef INET6
163 struct in6_addrpolicy pc_policy;
164 #endif
165 };
166 TAILQ_HEAD(policyhead, policyqueue);
167
168 #define AIO_SRCFLAG_DEPRECATED 0x1
169
170 struct hp_order {
171 union {
172 struct sockaddr_storage aiou_ss;
173 struct sockaddr aiou_sa;
174 } aio_src_un;
175 #define aio_srcsa aio_src_un.aiou_sa
176 u_int32_t aio_srcflag;
177 int aio_srcscope;
178 int aio_dstscope;
179 struct policyqueue *aio_srcpolicy;
180 struct policyqueue *aio_dstpolicy;
181 union {
182 struct sockaddr_storage aiou_ss;
183 struct sockaddr aiou_sa;
184 } aio_un;
185 #define aio_sa aio_un.aiou_sa
186 int aio_matchlen;
187 char *aio_h_addr;
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 static struct hostent *_hpreorder(struct hostent *);
199 static int get_addrselectpolicy(struct policyhead *);
200 static void free_addrselectpolicy(struct policyhead *);
201 static struct policyqueue *match_addrselectpolicy(struct sockaddr *,
202 struct policyhead *);
203 static void set_source(struct hp_order *, struct policyhead *);
204 static int matchlen(struct sockaddr *, struct sockaddr *);
205 static int comp_dst(const void *, const void *);
206 static int gai_addr2scopetype(struct sockaddr *);
207
208 /*
209 * Functions defined in RFC2553
210 * getipnodebyname, getipnodebyaddr, freehostent
211 */
212
213 struct hostent *
getipnodebyname(const char * name,int af,int flags,int * errp)214 getipnodebyname(const char *name, int af, int flags, int *errp)
215 {
216 struct hostent *hp;
217 union inx_addr addrbuf;
218 res_state statp;
219 u_long options;
220
221 switch (af) {
222 case AF_INET:
223 #ifdef INET6
224 case AF_INET6:
225 #endif
226 break;
227 default:
228 *errp = NO_RECOVERY;
229 return NULL;
230 }
231
232 if (flags & AI_ADDRCONFIG) {
233 int s;
234
235 if ((s = _socket(af, SOCK_DGRAM, 0)) < 0)
236 return NULL;
237 /*
238 * TODO:
239 * Note that implementation dependent test for address
240 * configuration should be done everytime called
241 * (or apropriate interval),
242 * because addresses will be dynamically assigned or deleted.
243 */
244 _close(s);
245 }
246
247 #ifdef INET6
248 /* special case for literal address */
249 if (inet_pton(AF_INET6, name, &addrbuf) == 1) {
250 if (af != AF_INET6) {
251 *errp = HOST_NOT_FOUND;
252 return NULL;
253 }
254 return _hpaddr(af, name, &addrbuf, errp);
255 }
256 #endif
257 if (inet_aton(name, (struct in_addr *)&addrbuf) == 1) {
258 if (af != AF_INET) {
259 if (MAPADDRENABLED(flags)) {
260 MAPADDR(&addrbuf, &addrbuf.in_addr);
261 } else {
262 *errp = HOST_NOT_FOUND;
263 return NULL;
264 }
265 }
266 return _hpaddr(af, name, &addrbuf, errp);
267 }
268
269
270 statp = __res_state();
271 if ((statp->options & RES_INIT) == 0) {
272 if (res_ninit(statp) < 0) {
273 *errp = NETDB_INTERNAL;
274 return NULL;
275 }
276 }
277
278 options = statp->options;
279 statp->options &= ~RES_USE_INET6;
280
281 hp = gethostbyname2(name, af);
282 hp = _hpcopy(hp, errp);
283
284 #ifdef INET6
285 if (af == AF_INET6 && ((flags & AI_ALL) || hp == NULL) &&
286 MAPADDRENABLED(flags)) {
287 struct hostent *hp2 = gethostbyname2(name, AF_INET);
288 if (hp == NULL)
289 if (hp2 == NULL)
290 *errp = statp->res_h_errno;
291 else
292 hp = _hpmapv6(hp2, errp);
293 else {
294 if (hp2 && strcmp(hp->h_name, hp2->h_name) == 0) {
295 struct hostent *hpb = hp;
296 hp = _hpmerge(hpb, hp2, errp);
297 freehostent(hpb);
298 }
299 }
300 }
301 #endif
302
303 if (hp == NULL)
304 *errp = statp->res_h_errno;
305
306 statp->options = options;
307 return _hpreorder(_hpsort(hp, statp));
308 }
309
310 struct hostent *
getipnodebyaddr(const void * src,size_t len,int af,int * errp)311 getipnodebyaddr(const void *src, size_t len, int af, int *errp)
312 {
313 struct hostent *hp;
314 res_state statp;
315 u_long options;
316
317 #ifdef INET6
318 struct in6_addr addrbuf;
319 #else
320 struct in_addr addrbuf;
321 #endif
322
323 switch (af) {
324 case AF_INET:
325 if (len != sizeof(struct in_addr)) {
326 *errp = NO_RECOVERY;
327 return NULL;
328 }
329 if (rounddown2((long)src, sizeof(struct in_addr))) {
330 memcpy(&addrbuf, src, len);
331 src = &addrbuf;
332 }
333 if (((struct in_addr *)src)->s_addr == 0)
334 return NULL;
335 break;
336 #ifdef INET6
337 case AF_INET6:
338 if (len != sizeof(struct in6_addr)) {
339 *errp = NO_RECOVERY;
340 return NULL;
341 }
342 if (rounddown2((long)src, sizeof(struct in6_addr) / 2)) { /*XXX*/
343 memcpy(&addrbuf, src, len);
344 src = &addrbuf;
345 }
346 if (IN6_IS_ADDR_UNSPECIFIED((struct in6_addr *)src))
347 return NULL;
348 if (IN6_IS_ADDR_V4MAPPED((struct in6_addr *)src)
349 || IN6_IS_ADDR_V4COMPAT((struct in6_addr *)src)) {
350 src = (char *)src +
351 (sizeof(struct in6_addr) - sizeof(struct in_addr));
352 af = AF_INET;
353 len = sizeof(struct in_addr);
354 }
355 break;
356 #endif
357 default:
358 *errp = NO_RECOVERY;
359 return NULL;
360 }
361
362 statp = __res_state();
363 if ((statp->options & RES_INIT) == 0) {
364 if (res_ninit(statp) < 0) {
365 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
366 return NULL;
367 }
368 }
369
370 options = statp->options;
371 statp->options &= ~RES_USE_INET6;
372
373 hp = gethostbyaddr(src, len, af);
374 if (hp == NULL)
375 *errp = statp->res_h_errno;
376
377 statp->options = options;
378 return (_hpcopy(hp, errp));
379 }
380
381 void
freehostent(struct hostent * ptr)382 freehostent(struct hostent *ptr)
383 {
384 free(ptr);
385 }
386
387 /*
388 * Private utility functions
389 */
390
391 /*
392 * _hpcopy: allocate and copy hostent structure
393 */
394 static struct hostent *
_hpcopy(struct hostent * hp,int * errp)395 _hpcopy(struct hostent *hp, int *errp)
396 {
397 struct hostent *nhp;
398 char *cp, **pp;
399 int size, addrsize;
400 int nalias = 0, naddr = 0;
401 int al_off;
402 int i;
403
404 if (hp == NULL)
405 return hp;
406
407 /* count size to be allocated */
408 size = sizeof(struct hostent);
409 if (hp->h_name != NULL)
410 size += strlen(hp->h_name) + 1;
411 if ((pp = hp->h_aliases) != NULL) {
412 for (i = 0; *pp != NULL; i++, pp++) {
413 if (**pp != '\0') {
414 size += strlen(*pp) + 1;
415 nalias++;
416 }
417 }
418 }
419 /* adjust alignment */
420 size = ALIGN(size);
421 al_off = size;
422 size += sizeof(char *) * (nalias + 1);
423 addrsize = ALIGN(hp->h_length);
424 if ((pp = hp->h_addr_list) != NULL) {
425 while (*pp++ != NULL)
426 naddr++;
427 }
428 size += addrsize * naddr;
429 size += sizeof(char *) * (naddr + 1);
430
431 /* copy */
432 if ((nhp = (struct hostent *)malloc(size)) == NULL) {
433 *errp = TRY_AGAIN;
434 return NULL;
435 }
436 cp = (char *)&nhp[1];
437 if (hp->h_name != NULL) {
438 nhp->h_name = cp;
439 strcpy(cp, hp->h_name);
440 cp += strlen(cp) + 1;
441 } else
442 nhp->h_name = NULL;
443 nhp->h_aliases = (char **)((char *)nhp + al_off);
444 if ((pp = hp->h_aliases) != NULL) {
445 for (i = 0; *pp != NULL; pp++) {
446 if (**pp != '\0') {
447 nhp->h_aliases[i++] = cp;
448 strcpy(cp, *pp);
449 cp += strlen(cp) + 1;
450 }
451 }
452 }
453 nhp->h_aliases[nalias] = NULL;
454 cp = (char *)&nhp->h_aliases[nalias + 1];
455 nhp->h_addrtype = hp->h_addrtype;
456 nhp->h_length = hp->h_length;
457 nhp->h_addr_list = (char **)cp;
458 if ((pp = hp->h_addr_list) != NULL) {
459 cp = (char *)&nhp->h_addr_list[naddr + 1];
460 for (i = 0; *pp != NULL; pp++) {
461 nhp->h_addr_list[i++] = cp;
462 memcpy(cp, *pp, hp->h_length);
463 cp += addrsize;
464 }
465 }
466 nhp->h_addr_list[naddr] = NULL;
467 return nhp;
468 }
469
470 /*
471 * _hpaddr: construct hostent structure with one address
472 */
473 static struct hostent *
_hpaddr(int af,const char * name,void * addr,int * errp)474 _hpaddr(int af, const char *name, void *addr, int *errp)
475 {
476 struct hostent *hp, hpbuf;
477 char *addrs[2];
478
479 hp = &hpbuf;
480 hp->h_name = (char *)name;
481 hp->h_aliases = NULL;
482 hp->h_addrtype = af;
483 hp->h_length = ADDRLEN(af);
484 hp->h_addr_list = addrs;
485 addrs[0] = (char *)addr;
486 addrs[1] = NULL;
487 return (_hpcopy(hp, errp));
488 }
489
490 #ifdef INET6
491 /*
492 * _hpmerge: merge 2 hostent structure, arguments will be freed
493 */
494 static struct hostent *
_hpmerge(struct hostent * hp1,struct hostent * hp2,int * errp)495 _hpmerge(struct hostent *hp1, struct hostent *hp2, int *errp)
496 {
497 int i, j;
498 int naddr, nalias;
499 char **pp;
500 struct hostent *hp, hpbuf;
501 char *aliases[MAXALIASES + 1], *addrs[MAXADDRS + 1];
502 union inx_addr addrbuf[MAXADDRS];
503
504 if (hp1 == NULL)
505 return _hpcopy(hp2, errp);
506 if (hp2 == NULL)
507 return _hpcopy(hp1, errp);
508
509 #define HP(i) (i == 1 ? hp1 : hp2)
510 hp = &hpbuf;
511 hp->h_name = (hp1->h_name != NULL ? hp1->h_name : hp2->h_name);
512 hp->h_aliases = aliases;
513 nalias = 0;
514 for (i = 1; i <= 2; i++) {
515 if ((pp = HP(i)->h_aliases) == NULL)
516 continue;
517 for (; nalias < MAXALIASES && *pp != NULL; pp++) {
518 /* check duplicates */
519 for (j = 0; j < nalias; j++)
520 if (strcasecmp(*pp, aliases[j]) == 0)
521 break;
522 if (j == nalias)
523 aliases[nalias++] = *pp;
524 }
525 }
526 aliases[nalias] = NULL;
527 if (hp1->h_length != hp2->h_length) {
528 hp->h_addrtype = AF_INET6;
529 hp->h_length = sizeof(struct in6_addr);
530 } else {
531 hp->h_addrtype = hp1->h_addrtype;
532 hp->h_length = hp1->h_length;
533 }
534
535 hp->h_addr_list = addrs;
536 naddr = 0;
537 for (i = 1; i <= 2; i++) {
538 if ((pp = HP(i)->h_addr_list) == NULL)
539 continue;
540 if (HP(i)->h_length == hp->h_length) {
541 while (naddr < MAXADDRS && *pp != NULL)
542 addrs[naddr++] = *pp++;
543 } else {
544 /* copy IPv4 addr as mapped IPv6 addr */
545 while (naddr < MAXADDRS && *pp != NULL) {
546 MAPADDR(&addrbuf[naddr], *pp++);
547 addrs[naddr] = (char *)&addrbuf[naddr];
548 naddr++;
549 }
550 }
551 }
552 addrs[naddr] = NULL;
553 return (_hpcopy(hp, errp));
554 }
555 #endif
556
557 /*
558 * _hpmapv6: convert IPv4 hostent into IPv4-mapped IPv6 addresses
559 */
560 #ifdef INET6
561 static struct hostent *
_hpmapv6(struct hostent * hp,int * errp)562 _hpmapv6(struct hostent *hp, int *errp)
563 {
564 struct hostent hp6;
565
566 if (hp == NULL)
567 return NULL;
568 if (hp->h_addrtype == AF_INET6)
569 return _hpcopy(hp, errp);
570
571 memset(&hp6, 0, sizeof(struct hostent));
572 hp6.h_addrtype = AF_INET6;
573 hp6.h_length = sizeof(struct in6_addr);
574 return _hpmerge(&hp6, hp, errp);
575 }
576 #endif
577
578 /*
579 * _hpsort: sort address by sortlist
580 */
581 static struct hostent *
_hpsort(struct hostent * hp,res_state statp)582 _hpsort(struct hostent *hp, res_state statp)
583 {
584 int i, j, n;
585 u_char *ap, *sp, *mp, **pp;
586 char t;
587 char order[MAXADDRS];
588 int nsort = statp->nsort;
589
590 if (hp == NULL || hp->h_addr_list[1] == NULL || nsort == 0)
591 return hp;
592 for (i = 0; (ap = (u_char *)hp->h_addr_list[i]); i++) {
593 for (j = 0; j < nsort; j++) {
594 #ifdef INET6
595 if (statp->_u._ext.ext->sort_list[j].af !=
596 hp->h_addrtype)
597 continue;
598 sp = (u_char *)&statp->_u._ext.ext->sort_list[j].addr;
599 mp = (u_char *)&statp->_u._ext.ext->sort_list[j].mask;
600 #else
601 sp = (u_char *)&statp->sort_list[j].addr;
602 mp = (u_char *)&statp->sort_list[j].mask;
603 #endif
604 for (n = 0; n < hp->h_length; n++) {
605 if ((ap[n] & mp[n]) != sp[n])
606 break;
607 }
608 if (n == hp->h_length)
609 break;
610 }
611 order[i] = j;
612 }
613 n = i;
614 pp = (u_char **)hp->h_addr_list;
615 for (i = 0; i < n - 1; i++) {
616 for (j = i + 1; j < n; j++) {
617 if (order[i] > order[j]) {
618 ap = pp[i];
619 pp[i] = pp[j];
620 pp[j] = ap;
621 t = order[i];
622 order[i] = order[j];
623 order[j] = t;
624 }
625 }
626 }
627 return hp;
628 }
629
630 /*
631 * _hpreorder: sort address by default address selection
632 */
633 static struct hostent *
_hpreorder(struct hostent * hp)634 _hpreorder(struct hostent *hp)
635 {
636 struct hp_order *aio;
637 int i, n;
638 char *ap;
639 struct sockaddr *sa;
640 struct policyhead policyhead;
641
642 if (hp == NULL)
643 return hp;
644
645 switch (hp->h_addrtype) {
646 case AF_INET:
647 #ifdef INET6
648 case AF_INET6:
649 #endif
650 break;
651 default:
652 free_addrselectpolicy(&policyhead);
653 return hp;
654 }
655
656 /* count the number of addrinfo elements for sorting. */
657 for (n = 0; hp->h_addr_list[n] != NULL; n++)
658 ;
659
660 /*
661 * If the number is small enough, we can skip the reordering process.
662 */
663 if (n <= 1)
664 return hp;
665
666 /* allocate a temporary array for sort and initialization of it. */
667 if ((aio = malloc(sizeof(*aio) * n)) == NULL)
668 return hp; /* give up reordering */
669 memset(aio, 0, sizeof(*aio) * n);
670
671 /* retrieve address selection policy from the kernel */
672 TAILQ_INIT(&policyhead);
673 if (!get_addrselectpolicy(&policyhead)) {
674 /* no policy is installed into kernel, we don't sort. */
675 free(aio);
676 return hp;
677 }
678
679 for (i = 0; i < n; i++) {
680 ap = hp->h_addr_list[i];
681 aio[i].aio_h_addr = ap;
682 sa = &aio[i].aio_sa;
683 switch (hp->h_addrtype) {
684 case AF_INET:
685 sa->sa_family = AF_INET;
686 sa->sa_len = sizeof(struct sockaddr_in);
687 memcpy(&((struct sockaddr_in *)sa)->sin_addr, ap,
688 sizeof(struct in_addr));
689 break;
690 #ifdef INET6
691 case AF_INET6:
692 if (IN6_IS_ADDR_V4MAPPED((struct in6_addr *)ap)) {
693 sa->sa_family = AF_INET;
694 sa->sa_len = sizeof(struct sockaddr_in);
695 memcpy(&((struct sockaddr_in *)sa)->sin_addr,
696 &ap[12], sizeof(struct in_addr));
697 } else {
698 sa->sa_family = AF_INET6;
699 sa->sa_len = sizeof(struct sockaddr_in6);
700 memcpy(&((struct sockaddr_in6 *)sa)->sin6_addr,
701 ap, sizeof(struct in6_addr));
702 }
703 break;
704 #endif
705 }
706 aio[i].aio_dstscope = gai_addr2scopetype(sa);
707 aio[i].aio_dstpolicy = match_addrselectpolicy(sa, &policyhead);
708 set_source(&aio[i], &policyhead);
709 }
710
711 /* perform sorting. */
712 qsort(aio, n, sizeof(*aio), comp_dst);
713
714 /* reorder the h_addr_list. */
715 for (i = 0; i < n; i++)
716 hp->h_addr_list[i] = aio[i].aio_h_addr;
717
718 /* cleanup and return */
719 free(aio);
720 free_addrselectpolicy(&policyhead);
721 return hp;
722 }
723
724 static int
get_addrselectpolicy(struct policyhead * head)725 get_addrselectpolicy(struct policyhead *head)
726 {
727 #ifdef INET6
728 int mib[] = { CTL_NET, PF_INET6, IPPROTO_IPV6, IPV6CTL_ADDRCTLPOLICY };
729 size_t l;
730 char *buf;
731 struct in6_addrpolicy *pol, *ep;
732
733 if (sysctl(mib, NELEM(mib), NULL, &l, NULL, 0) < 0)
734 return (0);
735 if ((buf = malloc(l)) == NULL)
736 return (0);
737 if (sysctl(mib, NELEM(mib), buf, &l, NULL, 0) < 0) {
738 free(buf);
739 return (0);
740 }
741
742 ep = (struct in6_addrpolicy *)(buf + l);
743 for (pol = (struct in6_addrpolicy *)buf; pol + 1 <= ep; pol++) {
744 struct policyqueue *new;
745
746 if ((new = malloc(sizeof(*new))) == NULL) {
747 free_addrselectpolicy(head); /* make the list empty */
748 break;
749 }
750 new->pc_policy = *pol;
751 TAILQ_INSERT_TAIL(head, new, pc_entry);
752 }
753
754 free(buf);
755 return (1);
756 #else
757 return (0);
758 #endif
759 }
760
761 static void
free_addrselectpolicy(struct policyhead * head)762 free_addrselectpolicy(struct policyhead *head)
763 {
764 struct policyqueue *ent, *nent;
765
766 for (ent = TAILQ_FIRST(head); ent; ent = nent) {
767 nent = TAILQ_NEXT(ent, pc_entry);
768 TAILQ_REMOVE(head, ent, pc_entry);
769 free(ent);
770 }
771 }
772
773 static struct policyqueue *
match_addrselectpolicy(struct sockaddr * addr,struct policyhead * head)774 match_addrselectpolicy(struct sockaddr *addr, struct policyhead *head)
775 {
776 #ifdef INET6
777 struct policyqueue *ent, *bestent = NULL;
778 struct in6_addrpolicy *pol;
779 int matchlen, bestmatchlen = -1;
780 u_char *mp, *ep, *k, *p, m;
781 struct sockaddr_in6 key;
782
783 switch(addr->sa_family) {
784 case AF_INET6:
785 key = *(struct sockaddr_in6 *)addr;
786 break;
787 case AF_INET:
788 /* convert the address into IPv4-mapped IPv6 address. */
789 memset(&key, 0, sizeof(key));
790 key.sin6_family = AF_INET6;
791 key.sin6_len = sizeof(key);
792 key.sin6_addr.s6_addr[10] = 0xff;
793 key.sin6_addr.s6_addr[11] = 0xff;
794 memcpy(&key.sin6_addr.s6_addr[12],
795 &((struct sockaddr_in *)addr)->sin_addr, 4);
796 break;
797 default:
798 return(NULL);
799 }
800
801 for (ent = TAILQ_FIRST(head); ent; ent = TAILQ_NEXT(ent, pc_entry)) {
802 pol = &ent->pc_policy;
803 matchlen = 0;
804
805 mp = (u_char *)&pol->addrmask.sin6_addr;
806 ep = mp + 16; /* XXX: scope field? */
807 k = (u_char *)&key.sin6_addr;
808 p = (u_char *)&pol->addr.sin6_addr;
809 for (; mp < ep && *mp; mp++, k++, p++) {
810 m = *mp;
811 if ((*k & m) != *p)
812 goto next; /* not match */
813 if (m == 0xff) /* short cut for a typical case */
814 matchlen += 8;
815 else {
816 while (m >= 0x80) {
817 matchlen++;
818 m <<= 1;
819 }
820 }
821 }
822
823 /* matched. check if this is better than the current best. */
824 if (matchlen > bestmatchlen) {
825 bestent = ent;
826 bestmatchlen = matchlen;
827 }
828
829 next:
830 continue;
831 }
832
833 return(bestent);
834 #else
835 return(NULL);
836 #endif
837
838 }
839
840 static void
set_source(struct hp_order * aio,struct policyhead * ph)841 set_source(struct hp_order *aio, struct policyhead *ph)
842 {
843 struct sockaddr_storage ss = aio->aio_un.aiou_ss;
844 socklen_t srclen;
845 int s;
846
847 /* set unspec ("no source is available"), just in case */
848 aio->aio_srcsa.sa_family = AF_UNSPEC;
849 aio->aio_srcscope = -1;
850
851 switch(ss.ss_family) {
852 case AF_INET:
853 ((struct sockaddr_in *)&ss)->sin_port = htons(1);
854 break;
855 #ifdef INET6
856 case AF_INET6:
857 ((struct sockaddr_in6 *)&ss)->sin6_port = htons(1);
858 break;
859 #endif
860 default: /* ignore unsupported AFs explicitly */
861 return;
862 }
863
864 /* open a socket to get the source address for the given dst */
865 if ((s = _socket(ss.ss_family, SOCK_DGRAM, IPPROTO_UDP)) < 0)
866 return; /* give up */
867 if (_connect(s, (struct sockaddr *)&ss, ss.ss_len) < 0)
868 goto cleanup;
869 srclen = ss.ss_len;
870 if (_getsockname(s, &aio->aio_srcsa, &srclen) < 0) {
871 aio->aio_srcsa.sa_family = AF_UNSPEC;
872 goto cleanup;
873 }
874 aio->aio_srcscope = gai_addr2scopetype(&aio->aio_srcsa);
875 aio->aio_srcpolicy = match_addrselectpolicy(&aio->aio_srcsa, ph);
876 aio->aio_matchlen = matchlen(&aio->aio_srcsa, (struct sockaddr *)&ss);
877 #ifdef INET6
878 if (ss.ss_family == AF_INET6) {
879 struct in6_ifreq ifr6;
880 u_int32_t flags6;
881
882 /* XXX: interface name should not be hardcoded */
883 strncpy(ifr6.ifr_name, "lo0", sizeof(ifr6.ifr_name));
884 memset(&ifr6, 0, sizeof(ifr6));
885 memcpy(&ifr6.ifr_addr, &ss, ss.ss_len);
886 if (_ioctl(s, SIOCGIFAFLAG_IN6, &ifr6) == 0) {
887 flags6 = ifr6.ifr_ifru.ifru_flags6;
888 if ((flags6 & IN6_IFF_DEPRECATED))
889 aio->aio_srcflag |= AIO_SRCFLAG_DEPRECATED;
890 }
891 }
892 #endif
893
894 cleanup:
895 _close(s);
896 return;
897 }
898
899 static int
matchlen(struct sockaddr * src,struct sockaddr * dst)900 matchlen(struct sockaddr *src, struct sockaddr *dst)
901 {
902 int match = 0;
903 u_char *s, *d;
904 u_char *lim, r;
905 int addrlen;
906
907 switch (src->sa_family) {
908 #ifdef INET6
909 case AF_INET6:
910 s = (u_char *)&((struct sockaddr_in6 *)src)->sin6_addr;
911 d = (u_char *)&((struct sockaddr_in6 *)dst)->sin6_addr;
912 addrlen = sizeof(struct in6_addr);
913 lim = s + addrlen;
914 break;
915 #endif
916 case AF_INET:
917 s = (u_char *)&((struct sockaddr_in *)src)->sin_addr;
918 d = (u_char *)&((struct sockaddr_in *)dst)->sin_addr;
919 addrlen = sizeof(struct in_addr);
920 lim = s + addrlen;
921 break;
922 default:
923 return(0);
924 }
925
926 while (s < lim)
927 if ((r = (*d++ ^ *s++)) != 0) {
928 while (r < addrlen * 8) {
929 match++;
930 r <<= 1;
931 }
932 break;
933 } else
934 match += 8;
935 return(match);
936 }
937
938 static int
comp_dst(const void * arg1,const void * arg2)939 comp_dst(const void *arg1, const void *arg2)
940 {
941 const struct hp_order *dst1 = arg1, *dst2 = arg2;
942
943 /*
944 * Rule 1: Avoid unusable destinations.
945 * XXX: we currently do not consider if an appropriate route exists.
946 */
947 if (dst1->aio_srcsa.sa_family != AF_UNSPEC &&
948 dst2->aio_srcsa.sa_family == AF_UNSPEC) {
949 return(-1);
950 }
951 if (dst1->aio_srcsa.sa_family == AF_UNSPEC &&
952 dst2->aio_srcsa.sa_family != AF_UNSPEC) {
953 return(1);
954 }
955
956 /* Rule 2: Prefer matching scope. */
957 if (dst1->aio_dstscope == dst1->aio_srcscope &&
958 dst2->aio_dstscope != dst2->aio_srcscope) {
959 return(-1);
960 }
961 if (dst1->aio_dstscope != dst1->aio_srcscope &&
962 dst2->aio_dstscope == dst2->aio_srcscope) {
963 return(1);
964 }
965
966 /* Rule 3: Avoid deprecated addresses. */
967 if (dst1->aio_srcsa.sa_family != AF_UNSPEC &&
968 dst2->aio_srcsa.sa_family != AF_UNSPEC) {
969 if (!(dst1->aio_srcflag & AIO_SRCFLAG_DEPRECATED) &&
970 (dst2->aio_srcflag & AIO_SRCFLAG_DEPRECATED)) {
971 return(-1);
972 }
973 if ((dst1->aio_srcflag & AIO_SRCFLAG_DEPRECATED) &&
974 !(dst2->aio_srcflag & AIO_SRCFLAG_DEPRECATED)) {
975 return(1);
976 }
977 }
978
979 /* Rule 4: Prefer home addresses. */
980 /* XXX: not implemented yet */
981
982 /* Rule 5: Prefer matching label. */
983 #ifdef INET6
984 if (dst1->aio_srcpolicy && dst1->aio_dstpolicy &&
985 dst1->aio_srcpolicy->pc_policy.label ==
986 dst1->aio_dstpolicy->pc_policy.label &&
987 (dst2->aio_srcpolicy == NULL || dst2->aio_dstpolicy == NULL ||
988 dst2->aio_srcpolicy->pc_policy.label !=
989 dst2->aio_dstpolicy->pc_policy.label)) {
990 return(-1);
991 }
992 if (dst2->aio_srcpolicy && dst2->aio_dstpolicy &&
993 dst2->aio_srcpolicy->pc_policy.label ==
994 dst2->aio_dstpolicy->pc_policy.label &&
995 (dst1->aio_srcpolicy == NULL || dst1->aio_dstpolicy == NULL ||
996 dst1->aio_srcpolicy->pc_policy.label !=
997 dst1->aio_dstpolicy->pc_policy.label)) {
998 return(1);
999 }
1000 #endif
1001
1002 /* Rule 6: Prefer higher precedence. */
1003 #ifdef INET6
1004 if (dst1->aio_dstpolicy &&
1005 (dst2->aio_dstpolicy == NULL ||
1006 dst1->aio_dstpolicy->pc_policy.preced >
1007 dst2->aio_dstpolicy->pc_policy.preced)) {
1008 return(-1);
1009 }
1010 if (dst2->aio_dstpolicy &&
1011 (dst1->aio_dstpolicy == NULL ||
1012 dst2->aio_dstpolicy->pc_policy.preced >
1013 dst1->aio_dstpolicy->pc_policy.preced)) {
1014 return(1);
1015 }
1016 #endif
1017
1018 /* Rule 7: Prefer native transport. */
1019 /* XXX: not implemented yet */
1020
1021 /* Rule 8: Prefer smaller scope. */
1022 if (dst1->aio_dstscope >= 0 &&
1023 dst1->aio_dstscope < dst2->aio_dstscope) {
1024 return(-1);
1025 }
1026 if (dst2->aio_dstscope >= 0 &&
1027 dst2->aio_dstscope < dst1->aio_dstscope) {
1028 return(1);
1029 }
1030
1031 /*
1032 * Rule 9: Use longest matching prefix.
1033 * We compare the match length in a same AF only.
1034 */
1035 if (dst1->aio_sa.sa_family == dst2->aio_sa.sa_family) {
1036 if (dst1->aio_matchlen > dst2->aio_matchlen) {
1037 return(-1);
1038 }
1039 if (dst1->aio_matchlen < dst2->aio_matchlen) {
1040 return(1);
1041 }
1042 }
1043
1044 /* Rule 10: Otherwise, leave the order unchanged. */
1045 return(-1);
1046 }
1047
1048 /*
1049 * Copy from scope.c.
1050 * XXX: we should standardize the functions and link them as standard
1051 * library.
1052 */
1053 static int
gai_addr2scopetype(struct sockaddr * sa)1054 gai_addr2scopetype(struct sockaddr *sa)
1055 {
1056 #ifdef INET6
1057 struct sockaddr_in6 *sa6;
1058 #endif
1059 struct sockaddr_in *sa4;
1060
1061 switch(sa->sa_family) {
1062 #ifdef INET6
1063 case AF_INET6:
1064 sa6 = (struct sockaddr_in6 *)sa;
1065 if (IN6_IS_ADDR_MULTICAST(&sa6->sin6_addr)) {
1066 /* just use the scope field of the multicast address */
1067 return(sa6->sin6_addr.s6_addr[2] & 0x0f);
1068 }
1069 /*
1070 * Unicast addresses: map scope type to corresponding scope
1071 * value defined for multcast addresses.
1072 * XXX: hardcoded scope type values are bad...
1073 */
1074 if (IN6_IS_ADDR_LOOPBACK(&sa6->sin6_addr))
1075 return(1); /* node local scope */
1076 if (IN6_IS_ADDR_LINKLOCAL(&sa6->sin6_addr))
1077 return(2); /* link-local scope */
1078 if (IN6_IS_ADDR_SITELOCAL(&sa6->sin6_addr))
1079 return(5); /* site-local scope */
1080 return(14); /* global scope */
1081 break;
1082 #endif
1083 case AF_INET:
1084 /*
1085 * IPv4 pseudo scoping according to RFC 3484.
1086 */
1087 sa4 = (struct sockaddr_in *)sa;
1088 /* IPv4 autoconfiguration addresses have link-local scope. */
1089 if (((u_char *)&sa4->sin_addr)[0] == 169 &&
1090 ((u_char *)&sa4->sin_addr)[1] == 254)
1091 return(2);
1092 /* Private addresses have site-local scope. */
1093 if (((u_char *)&sa4->sin_addr)[0] == 10 ||
1094 (((u_char *)&sa4->sin_addr)[0] == 172 &&
1095 (((u_char *)&sa4->sin_addr)[1] & 0xf0) == 16) ||
1096 (((u_char *)&sa4->sin_addr)[0] == 192 &&
1097 ((u_char *)&sa4->sin_addr)[1] == 168))
1098 return(14); /* XXX: It should be 5 unless NAT */
1099 /* Loopback addresses have link-local scope. */
1100 if (((u_char *)&sa4->sin_addr)[0] == 127)
1101 return(2);
1102 return(14);
1103 break;
1104 default:
1105 errno = EAFNOSUPPORT; /* is this a good error? */
1106 return(-1);
1107 }
1108 }
1109