1 /* $NetBSD: getnameinfo.c,v 1.43 2006/02/17 15:58:26 ginsbach Exp $ */
2 /* $KAME: getnameinfo.c,v 1.45 2000/09/25 22:43:56 itojun Exp $ */
3
4 /*
5 * Copyright (c) 2000 Ben Harris.
6 * Copyright (C) 1995, 1996, 1997, and 1998 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 /*
35 * Issues to be discussed:
36 * - Thread safe-ness must be checked
37 * - RFC2553 says that we should raise error on short buffer. X/Open says
38 * we need to truncate the result. We obey RFC2553 (and X/Open should be
39 * modified). ipngwg rough consensus seems to follow RFC2553.
40 * - What is "local" in NI_FQDN?
41 * - NI_NAMEREQD and NI_NUMERICHOST conflict with each other.
42 * - (KAME extension) always attach textual scopeid (fe80::1%lo0), if
43 * sin6_scope_id is filled - standardization status?
44 * XXX breaks backward compat for code that expects no scopeid.
45 * beware on merge.
46 */
47
48 #include <sys/cdefs.h>
49 #if defined(LIBC_SCCS) && !defined(lint)
50 __RCSID("$NetBSD: getnameinfo.c,v 1.43 2006/02/17 15:58:26 ginsbach Exp $");
51 #endif /* LIBC_SCCS and not lint */
52
53 #include <sys/types.h>
54 #include <sys/socket.h>
55 #include <net/if.h>
56 #include <net/if_dl.h>
57 #include <net/if_ieee1394.h>
58 #include <net/if_types.h>
59 #include <netinet/in.h>
60 #include <arpa/inet.h>
61 #include "arpa_nameser.h"
62 #include <assert.h>
63 #include <limits.h>
64 #include <netdb.h>
65 #ifdef ANDROID_CHANGES
66 #include "resolv_private.h"
67 #include <sys/system_properties.h>
68 #include <stdlib.h>
69 #include <unistd.h>
70 #include <sys/un.h>
71 #include <errno.h>
72 #else
73 #include <resolv.h>
74 #endif
75 #include <stddef.h>
76 #include <string.h>
77
78 static const struct afd {
79 int a_af;
80 socklen_t a_addrlen;
81 socklen_t a_socklen;
82 int a_off;
83 } afdl [] = {
84 #ifdef INET6
85 {PF_INET6, sizeof(struct in6_addr), sizeof(struct sockaddr_in6),
86 offsetof(struct sockaddr_in6, sin6_addr)},
87 #endif
88 {PF_INET, sizeof(struct in_addr), sizeof(struct sockaddr_in),
89 offsetof(struct sockaddr_in, sin_addr)},
90 {0, 0, 0, 0},
91 };
92
93 struct sockinet {
94 u_char si_len;
95 u_char si_family;
96 u_short si_port;
97 };
98
99 static int getnameinfo_inet __P((const struct sockaddr *, socklen_t, char *,
100 socklen_t, char *, socklen_t, int));
101 #ifdef INET6
102 static int ip6_parsenumeric __P((const struct sockaddr *, const char *, char *,
103 socklen_t, int));
104 static int ip6_sa2str __P((const struct sockaddr_in6 *, char *, size_t,
105 int));
106 #endif
107 static int getnameinfo_link __P((const struct sockaddr *, socklen_t, char *,
108 socklen_t, char *, socklen_t, int));
109 static int hexname __P((const u_int8_t *, size_t, char *, socklen_t));
110
111 /*
112 * Top-level getnameinfo() code. Look at the address family, and pick an
113 * appropriate function to call.
114 */
getnameinfo(const struct sockaddr * sa,socklen_t salen,char * host,size_t hostlen,char * serv,size_t servlen,int flags)115 int getnameinfo(const struct sockaddr* sa, socklen_t salen, char* host, size_t hostlen, char* serv, size_t servlen, int flags)
116 {
117 switch (sa->sa_family) {
118 case AF_INET:
119 case AF_INET6:
120 return getnameinfo_inet(sa, salen, host, hostlen,
121 serv, servlen, flags);
122 #if 0
123 case AF_LINK:
124 return getnameinfo_link(sa, salen, host, hostlen,
125 serv, servlen, flags);
126 #endif
127 default:
128 return EAI_FAMILY;
129 }
130 }
131
132 #ifdef ANDROID_CHANGES
133 /* On success length of the host name is returned. A return
134 * value of 0 means there's no host name associated with
135 * the address. On failure -1 is returned in which case
136 * normal execution flow shall continue. */
137 static int
android_gethostbyaddr_proxy(struct hostent * hp,const void * addr,socklen_t addrLen,int addrFamily)138 android_gethostbyaddr_proxy(struct hostent* hp, const void *addr, socklen_t addrLen, int addrFamily) {
139
140 int sock;
141 const int one = 1;
142 struct sockaddr_un proxy_addr;
143 const char* cache_mode = getenv("ANDROID_DNS_MODE");
144 FILE* proxy = NULL;
145 int result = -1;
146
147 if (cache_mode != NULL && strcmp(cache_mode, "local") == 0) {
148 // Don't use the proxy in local mode. This is used by the
149 // proxy itself.
150 return -1;
151 }
152
153 // Temporary cautious hack to disable the DNS proxy for processes
154 // requesting special treatment. Ideally the DNS proxy should
155 // accomodate these apps, though.
156 char propname[PROP_NAME_MAX];
157 char propvalue[PROP_VALUE_MAX];
158 snprintf(propname, sizeof(propname), "net.dns1.%d", getpid());
159 if (__system_property_get(propname, propvalue) > 0) {
160 return -1;
161 }
162 // create socket
163 sock = socket(AF_UNIX, SOCK_STREAM, 0);
164 if (sock < 0) {
165 return -1;
166 }
167
168 setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
169 memset(&proxy_addr, 0, sizeof(proxy_addr));
170 proxy_addr.sun_family = AF_UNIX;
171 strlcpy(proxy_addr.sun_path, "/dev/socket/dnsproxyd",
172 sizeof(proxy_addr.sun_path));
173 if (TEMP_FAILURE_RETRY(connect(sock, (const struct sockaddr*) (void*) &proxy_addr,
174 sizeof(proxy_addr))) != 0) {
175 close(sock);
176 return -1;
177 }
178
179 // send request to DnsProxyListener
180 proxy = fdopen(sock,"r+");
181 if (proxy == NULL) {
182 goto exit;
183 }
184
185 char buf[INET6_ADDRSTRLEN]; // big enough for IPv4 and IPv6
186 const char* addrStr = inet_ntop(addrFamily, addr, &buf, sizeof(buf));
187 if (addrStr == NULL) {
188 goto exit;
189 }
190 if (fprintf(proxy, "gethostbyaddr %s %d %d", addrStr, addrLen, addrFamily) < 0) {
191 goto exit;
192 }
193
194 // literal NULL byte at end, required by FrameworkListener
195 if (fputc(0, proxy) == EOF || fflush(proxy) != 0) {
196 goto exit;
197 }
198
199 result = 0;
200 uint32_t name_len;
201 if (fread(&name_len, sizeof(name_len), 1, proxy) != 1) {
202 goto exit;
203 }
204
205 name_len = ntohl(name_len);
206 if (name_len <= 0) {
207 goto exit;
208 }
209
210 if (fread(hp->h_name, name_len, 1, proxy) != 1) {
211 goto exit;
212 }
213
214 result = name_len;
215
216 exit:
217 if (proxy != NULL) {
218 fclose(proxy);
219 }
220
221 return result;
222 }
223 #endif
224 /*
225 * getnameinfo_inet():
226 * Format an IPv4 or IPv6 sockaddr into a printable string.
227 */
228 static int
getnameinfo_inet(sa,salen,host,hostlen,serv,servlen,flags)229 getnameinfo_inet(sa, salen, host, hostlen, serv, servlen, flags)
230 const struct sockaddr *sa;
231 socklen_t salen;
232 char *host;
233 socklen_t hostlen;
234 char *serv;
235 socklen_t servlen;
236 int flags;
237 {
238 const struct afd *afd;
239 struct servent *sp;
240 struct hostent *hp;
241 u_short port;
242 int family, i;
243 const char *addr;
244 u_int32_t v4a;
245 char numserv[512];
246 char numaddr[512];
247
248 /* sa is checked below */
249 /* host may be NULL */
250 /* serv may be NULL */
251
252 if (sa == NULL)
253 return EAI_FAIL;
254
255 #ifdef BSD4_4
256 if (sa->sa_len != salen)
257 return EAI_FAIL;
258 #endif
259
260 family = sa->sa_family;
261 for (i = 0; afdl[i].a_af; i++)
262 if (afdl[i].a_af == family) {
263 afd = &afdl[i];
264 goto found;
265 }
266 return EAI_FAMILY;
267
268 found:
269 if (salen != afd->a_socklen)
270 return EAI_FAIL;
271
272 /* network byte order */
273 port = ((const struct sockinet *)(const void *)sa)->si_port;
274 addr = (const char *)(const void *)sa + afd->a_off;
275
276 if (serv == NULL || servlen == 0) {
277 /*
278 * do nothing in this case.
279 * in case you are wondering if "&&" is more correct than
280 * "||" here: rfc2553bis-03 says that serv == NULL OR
281 * servlen == 0 means that the caller does not want the result.
282 */
283 } else {
284 if (flags & NI_NUMERICSERV)
285 sp = NULL;
286 else {
287 sp = getservbyport(port,
288 (flags & NI_DGRAM) ? "udp" : "tcp");
289 }
290 if (sp) {
291 if (strlen(sp->s_name) + 1 > (size_t)servlen)
292 return EAI_MEMORY;
293 strlcpy(serv, sp->s_name, servlen);
294 } else {
295 snprintf(numserv, sizeof(numserv), "%u", ntohs(port));
296 if (strlen(numserv) + 1 > (size_t)servlen)
297 return EAI_MEMORY;
298 strlcpy(serv, numserv, servlen);
299 }
300 }
301
302 switch (sa->sa_family) {
303 case AF_INET:
304 v4a = (u_int32_t)
305 ntohl(((const struct sockaddr_in *)
306 (const void *)sa)->sin_addr.s_addr);
307 if (IN_MULTICAST(v4a) || IN_EXPERIMENTAL(v4a))
308 flags |= NI_NUMERICHOST;
309 v4a >>= IN_CLASSA_NSHIFT;
310 if (v4a == 0)
311 flags |= NI_NUMERICHOST;
312 break;
313 #ifdef INET6
314 case AF_INET6:
315 {
316 const struct sockaddr_in6 *sin6;
317 sin6 = (const struct sockaddr_in6 *)(const void *)sa;
318 switch (sin6->sin6_addr.s6_addr[0]) {
319 case 0x00:
320 if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr))
321 ;
322 else if (IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr))
323 ;
324 else
325 flags |= NI_NUMERICHOST;
326 break;
327 default:
328 if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr)) {
329 flags |= NI_NUMERICHOST;
330 }
331 else if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr))
332 flags |= NI_NUMERICHOST;
333 break;
334 }
335 }
336 break;
337 #endif
338 }
339 if (host == NULL || hostlen == 0) {
340 /*
341 * do nothing in this case.
342 * in case you are wondering if "&&" is more correct than
343 * "||" here: rfc2553bis-03 says that host == NULL or
344 * hostlen == 0 means that the caller does not want the result.
345 */
346 } else if (flags & NI_NUMERICHOST) {
347 size_t numaddrlen;
348
349 /* NUMERICHOST and NAMEREQD conflicts with each other */
350 if (flags & NI_NAMEREQD)
351 return EAI_NONAME;
352
353 switch(afd->a_af) {
354 #ifdef INET6
355 case AF_INET6:
356 {
357 int error;
358
359 if ((error = ip6_parsenumeric(sa, addr, host,
360 hostlen, flags)) != 0)
361 return(error);
362 break;
363 }
364 #endif
365 default:
366 if (inet_ntop(afd->a_af, addr, numaddr, sizeof(numaddr))
367 == NULL)
368 return EAI_SYSTEM;
369 numaddrlen = strlen(numaddr);
370 if (numaddrlen + 1 > (size_t)hostlen) /* don't forget terminator */
371 return EAI_MEMORY;
372 strlcpy(host, numaddr, hostlen);
373 break;
374 }
375 } else {
376 #ifdef ANDROID_CHANGES
377 struct hostent android_proxy_hostent;
378 char android_proxy_buf[MAXDNAME];
379 android_proxy_hostent.h_name = android_proxy_buf;
380
381 int hostnamelen = android_gethostbyaddr_proxy(&android_proxy_hostent,
382 addr, afd->a_addrlen, afd->a_af);
383 if (hostnamelen >= 0) {
384 hp = (hostnamelen > 0) ? &android_proxy_hostent : NULL;
385 } else {
386 hp = gethostbyaddr(addr, afd->a_addrlen, afd->a_af);
387 }
388 #else
389 hp = gethostbyaddr(addr, afd->a_addrlen, afd->a_af);
390 #endif
391
392 if (hp) {
393 #if 0
394 /*
395 * commented out, since "for local host" is not
396 * implemented here - see RFC2553 p30
397 */
398 if (flags & NI_NOFQDN) {
399 char *p;
400 p = strchr(hp->h_name, '.');
401 if (p)
402 *p = '\0';
403 }
404 #endif
405 if (strlen(hp->h_name) + 1 > (size_t)hostlen) {
406 return EAI_MEMORY;
407 }
408 strlcpy(host, hp->h_name, hostlen);
409 } else {
410 if (flags & NI_NAMEREQD)
411 return EAI_NONAME;
412 switch(afd->a_af) {
413 #ifdef INET6
414 case AF_INET6:
415 {
416 int error;
417
418 if ((error = ip6_parsenumeric(sa, addr, host,
419 hostlen,
420 flags)) != 0)
421 return(error);
422 break;
423 }
424 #endif
425 default:
426 if (inet_ntop(afd->a_af, addr, host,
427 hostlen) == NULL)
428 return EAI_SYSTEM;
429 break;
430 }
431 }
432 }
433 return(0);
434 }
435
436 #ifdef INET6
437 static int
ip6_parsenumeric(sa,addr,host,hostlen,flags)438 ip6_parsenumeric(sa, addr, host, hostlen, flags)
439 const struct sockaddr *sa;
440 const char *addr;
441 char *host;
442 socklen_t hostlen;
443 int flags;
444 {
445 size_t numaddrlen;
446 char numaddr[512];
447
448 assert(sa != NULL);
449 assert(addr != NULL);
450 assert(host != NULL);
451
452 if (hostlen < 0)
453 return EAI_OVERFLOW;
454
455 if (inet_ntop(AF_INET6, addr, numaddr, sizeof(numaddr)) == NULL)
456 return EAI_SYSTEM;
457
458 numaddrlen = strlen(numaddr);
459 if (numaddrlen + 1 > (size_t)hostlen) /* don't forget terminator */
460 return EAI_OVERFLOW;
461 strlcpy(host, numaddr, hostlen);
462
463 if (((const struct sockaddr_in6 *)(const void *)sa)->sin6_scope_id) {
464 char zonebuf[MAXHOSTNAMELEN];
465 int zonelen;
466
467 zonelen = ip6_sa2str(
468 (const struct sockaddr_in6 *)(const void *)sa,
469 zonebuf, sizeof(zonebuf), flags);
470 if (zonelen < 0)
471 return EAI_OVERFLOW;
472 if ((size_t) zonelen + 1 + numaddrlen + 1 > (size_t)hostlen)
473 return EAI_OVERFLOW;
474 /* construct <numeric-addr><delim><zoneid> */
475 memcpy(host + numaddrlen + 1, zonebuf,
476 (size_t)zonelen);
477 host[numaddrlen] = SCOPE_DELIMITER;
478 host[numaddrlen + 1 + zonelen] = '\0';
479 }
480
481 return 0;
482 }
483
484 /* ARGSUSED */
485 static int
ip6_sa2str(sa6,buf,bufsiz,flags)486 ip6_sa2str(sa6, buf, bufsiz, flags)
487 const struct sockaddr_in6 *sa6;
488 char *buf;
489 size_t bufsiz;
490 int flags;
491 {
492 unsigned int ifindex;
493 const struct in6_addr *a6;
494 int n;
495
496 assert(sa6 != NULL);
497 assert(buf != NULL);
498
499 ifindex = (unsigned int)sa6->sin6_scope_id;
500 a6 = &sa6->sin6_addr;
501
502 #ifdef NI_NUMERICSCOPE
503 if ((flags & NI_NUMERICSCOPE) != 0) {
504 n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id);
505 if (n < 0 || n >= bufsiz)
506 return -1;
507 else
508 return n;
509 }
510 #endif
511
512 /* if_indextoname() does not take buffer size. not a good api... */
513 if ((IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6)) &&
514 bufsiz >= IF_NAMESIZE) {
515 char *p = if_indextoname(ifindex, buf);
516 if (p) {
517 return(strlen(p));
518 }
519 }
520
521 /* last resort */
522 n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id);
523 if (n < 0 || (size_t) n >= bufsiz)
524 return -1;
525 else
526 return n;
527 }
528 #endif /* INET6 */
529
530
531 /*
532 * getnameinfo_link():
533 * Format a link-layer address into a printable format, paying attention to
534 * the interface type.
535 */
536 /* ARGSUSED */
537 static int
getnameinfo_link(const struct sockaddr * sa,socklen_t salen,char * host,socklen_t hostlen,char * serv,socklen_t servlen,int flags)538 getnameinfo_link(const struct sockaddr *sa, socklen_t salen,
539 char *host, socklen_t hostlen, char *serv, socklen_t servlen,
540 int flags)
541 {
542 const struct sockaddr_dl *sdl =
543 (const struct sockaddr_dl *)(const void *)sa;
544 const struct ieee1394_hwaddr *iha;
545 int n;
546
547 if (serv != NULL && servlen > 0)
548 *serv = '\0';
549
550 if (sdl->sdl_nlen == 0 && sdl->sdl_alen == 0 && sdl->sdl_slen == 0) {
551 n = snprintf(host, hostlen, "link#%u", sdl->sdl_index);
552 if (n < 0 || (socklen_t) n > hostlen) {
553 *host = '\0';
554 return EAI_MEMORY;
555 }
556 return 0;
557 }
558
559 switch (sdl->sdl_type) {
560 #ifdef IFT_ECONET
561 case IFT_ECONET:
562 if (sdl->sdl_alen < 2)
563 return EAI_FAMILY;
564 if (CLLADDR(sdl)[1] == 0)
565 n = snprintf(host, hostlen, "%u", CLLADDR(sdl)[0]);
566 else
567 n = snprintf(host, hostlen, "%u.%u",
568 CLLADDR(sdl)[1], CLLADDR(sdl)[0]);
569 if (n < 0 || (socklen_t) n >= hostlen) {
570 *host = '\0';
571 return EAI_MEMORY;
572 } else
573 return 0;
574 #endif
575 case IFT_IEEE1394:
576 if (sdl->sdl_alen < sizeof(iha->iha_uid))
577 return EAI_FAMILY;
578 iha =
579 (const struct ieee1394_hwaddr *)(const void *)CLLADDR(sdl);
580 return hexname(iha->iha_uid, sizeof(iha->iha_uid),
581 host, hostlen);
582 /*
583 * The following have zero-length addresses.
584 * IFT_ATM (net/if_atmsubr.c)
585 * IFT_FAITH (net/if_faith.c)
586 * IFT_GIF (net/if_gif.c)
587 * IFT_LOOP (net/if_loop.c)
588 * IFT_PPP (net/if_ppp.c, net/if_spppsubr.c)
589 * IFT_SLIP (net/if_sl.c, net/if_strip.c)
590 * IFT_STF (net/if_stf.c)
591 * IFT_L2VLAN (net/if_vlan.c)
592 * IFT_PROPVIRTUAL (net/if_bridge.h>
593 */
594 /*
595 * The following use IPv4 addresses as link-layer addresses:
596 * IFT_OTHER (net/if_gre.c)
597 */
598 case IFT_ARCNET: /* default below is believed correct for all these. */
599 case IFT_ETHER:
600 case IFT_FDDI:
601 case IFT_HIPPI:
602 case IFT_ISO88025:
603 default:
604 return hexname((const u_int8_t *)CLLADDR(sdl),
605 (size_t)sdl->sdl_alen, host, hostlen);
606 }
607 }
608
609 static int
hexname(cp,len,host,hostlen)610 hexname(cp, len, host, hostlen)
611 const u_int8_t *cp;
612 char *host;
613 size_t len;
614 socklen_t hostlen;
615 {
616 int n;
617 size_t i;
618 char *outp = host;
619
620 *outp = '\0';
621 for (i = 0; i < len; i++) {
622 n = snprintf(outp, hostlen, "%s%02x",
623 i ? ":" : "", cp[i]);
624 if (n < 0 || (socklen_t) n >= hostlen) {
625 *host = '\0';
626 return EAI_MEMORY;
627 }
628 outp += n;
629 hostlen -= n;
630 }
631 return 0;
632 }
633