1 /* $KAME: getnameinfo.c,v 1.61 2002/06/27 09:25:47 itojun Exp $ */
2
3 /*-
4 * SPDX-License-Identifier: BSD-3-Clause
5 *
6 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
7 * Copyright (c) 2000 Ben Harris.
8 * All rights reserved.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the project nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35 /*
36 * Issues to be discussed:
37 * - Thread safe-ness must be checked
38 * - RFC2553 says that we should raise error on short buffer. X/Open says
39 * we need to truncate the result. We obey RFC2553 (and X/Open should be
40 * modified). ipngwg rough consensus seems to follow RFC2553.
41 * - What is "local" in NI_FQDN?
42 * - NI_NAMEREQD and NI_NUMERICHOST conflict with each other.
43 * - (KAME extension) always attach textual scopeid (fe80::1%lo0), if
44 * sin6_scope_id is filled - standardization status?
45 * XXX breaks backward compat for code that expects no scopeid.
46 * beware on merge.
47 */
48
49 #include <sys/types.h>
50 #include <sys/socket.h>
51 #include <sys/un.h>
52 #include <net/if.h>
53 #include <net/if_dl.h>
54 #include <net/if_types.h>
55 #include <net/firewire.h>
56 #include <netinet/in.h>
57 #include <arpa/inet.h>
58 #include <arpa/nameser.h>
59 #include <netdb.h>
60 #include <resolv.h>
61 #include <string.h>
62 #include <stddef.h>
63 #include <errno.h>
64
65 static const struct afd *find_afd(int);
66 static int getnameinfo_inet(const struct afd *,
67 const struct sockaddr *, socklen_t, char *,
68 size_t, char *, size_t, int);
69 #ifdef INET6
70 static int ip6_parsenumeric(const struct sockaddr *, const char *, char *,
71 size_t, int);
72 static int ip6_sa2str(const struct sockaddr_in6 *, char *, size_t, int);
73 #endif
74 static int getnameinfo_link(const struct afd *,
75 const struct sockaddr *, socklen_t, char *,
76 size_t, char *, size_t, int);
77 static int hexname(const u_int8_t *, size_t, char *, size_t);
78 static int getnameinfo_un(const struct afd *,
79 const struct sockaddr *, socklen_t, char *,
80 size_t, char *, size_t, int);
81
82 static const struct afd {
83 int a_af;
84 size_t a_addrlen;
85 socklen_t a_socklen;
86 int a_off;
87 int (*a_func)(const struct afd *,
88 const struct sockaddr *, socklen_t, char *,
89 size_t, char *, size_t, int);
90 } afdl [] = {
91 #ifdef INET6
92 {PF_INET6, sizeof(struct in6_addr), sizeof(struct sockaddr_in6),
93 offsetof(struct sockaddr_in6, sin6_addr),
94 getnameinfo_inet},
95 #endif
96 {PF_INET, sizeof(struct in_addr), sizeof(struct sockaddr_in),
97 offsetof(struct sockaddr_in, sin_addr),
98 getnameinfo_inet},
99 #define sizeofmember(type, member) (sizeof(((type *)0)->member))
100 {PF_LOCAL, sizeofmember(struct sockaddr_un, sun_path),
101 sizeof(struct sockaddr_un),
102 offsetof(struct sockaddr_un, sun_path),
103 getnameinfo_un},
104 {PF_LINK, sizeofmember(struct sockaddr_dl, sdl_data),
105 sizeof(struct sockaddr_dl),
106 offsetof(struct sockaddr_dl, sdl_data),
107 getnameinfo_link},
108 {0, 0, 0},
109 };
110
111 int
getnameinfo(const struct sockaddr * sa,socklen_t salen,char * host,size_t hostlen,char * serv,size_t servlen,int flags)112 getnameinfo(const struct sockaddr *sa, socklen_t salen,
113 char *host, size_t hostlen, char *serv, size_t servlen,
114 int flags)
115 {
116 const struct afd *afd;
117
118 if (sa == NULL)
119 return (EAI_FAIL);
120
121 afd = find_afd(sa->sa_family);
122 if (afd == NULL)
123 return (EAI_FAMILY);
124 /*
125 * getnameinfo() accepts an salen of sizeof(struct sockaddr_storage)
126 * at maximum as shown in RFC 4038 Sec.6.2.3.
127 */
128 if (salen > sizeof(struct sockaddr_storage))
129 return (EAI_FAMILY);
130
131 switch (sa->sa_family) {
132 case PF_LOCAL:
133 /*
134 * PF_LOCAL uses variable salen depending on the
135 * content length of sun_path. Require 1 byte in
136 * sun_path at least.
137 */
138 if (salen <= afd->a_socklen -
139 sizeofmember(struct sockaddr_un, sun_path))
140 return (EAI_FAMILY);
141 else if (salen > afd->a_socklen)
142 salen = afd->a_socklen;
143 break;
144 case PF_LINK:
145 if (salen <= afd->a_socklen -
146 sizeofmember(struct sockaddr_dl, sdl_data))
147 return (EAI_FAMILY);
148 break;
149 default:
150 if (salen < afd->a_socklen)
151 return (EAI_FAMILY);
152 else
153 salen = afd->a_socklen;
154 break;
155 }
156
157 return ((*afd->a_func)(afd, sa, salen, host, hostlen,
158 serv, servlen, flags));
159 }
160
161 static const struct afd *
find_afd(int af)162 find_afd(int af)
163 {
164 const struct afd *afd;
165
166 if (af == PF_UNSPEC)
167 return (NULL);
168 for (afd = &afdl[0]; afd->a_af > 0; afd++) {
169 if (afd->a_af == af)
170 return (afd);
171 }
172 return (NULL);
173 }
174
175 static int
getnameinfo_inet(const struct afd * afd,const struct sockaddr * sa,socklen_t salen,char * host,size_t hostlen,char * serv,size_t servlen,int flags)176 getnameinfo_inet(const struct afd *afd,
177 const struct sockaddr *sa, socklen_t salen,
178 char *host, size_t hostlen, char *serv, size_t servlen,
179 int flags)
180 {
181 struct servent *sp;
182 struct hostent *hp;
183 u_short port;
184 const char *addr;
185 u_int32_t v4a;
186 int h_error;
187 char numserv[512];
188 char numaddr[512];
189
190 /* network byte order */
191 port = ((const struct sockaddr_in *)sa)->sin_port;
192 addr = (const char *)sa + afd->a_off;
193
194 if (serv == NULL || servlen == 0) {
195 /*
196 * do nothing in this case.
197 * in case you are wondering if "&&" is more correct than
198 * "||" here: rfc2553bis-03 says that serv == NULL OR
199 * servlen == 0 means that the caller does not want the result.
200 */
201 } else {
202 if (flags & NI_NUMERICSERV)
203 sp = NULL;
204 else {
205 sp = getservbyport(port,
206 (flags & NI_DGRAM) ? "udp" : "tcp");
207 }
208 if (sp) {
209 if (strlen(sp->s_name) + 1 > servlen)
210 return EAI_MEMORY;
211 strlcpy(serv, sp->s_name, servlen);
212 } else {
213 snprintf(numserv, sizeof(numserv), "%u", ntohs(port));
214 if (strlen(numserv) + 1 > servlen)
215 return EAI_MEMORY;
216 strlcpy(serv, numserv, servlen);
217 }
218 }
219
220 switch (sa->sa_family) {
221 case AF_INET:
222 v4a = (u_int32_t)
223 ntohl(((const struct sockaddr_in *)sa)->sin_addr.s_addr);
224 if (IN_MULTICAST(v4a) || IN_EXPERIMENTAL(v4a) ||
225 IN_ZERONET(v4a))
226 flags |= NI_NUMERICHOST;
227 break;
228 #ifdef INET6
229 case AF_INET6:
230 {
231 const struct sockaddr_in6 *sin6;
232
233 sin6 = (const struct sockaddr_in6 *)sa;
234
235 /*
236 * https://pubs.opengroup.org/onlinepubs/9699919799/functions/getnameinfo.html
237 * "[IP6] [Option Start] If the socket address structure
238 * contains an IPv4-mapped IPv6 address or an IPv4-compatible
239 * IPv6 address, the implementation shall extract the embedded
240 * IPv4 address and lookup the node name for that IPv4 address.
241 * [Option End]"
242 * => getipnodebyaddr() handles this case for us.
243 * => in case of NI_NUMERICHOST being set, inet_ntop[6] will
244 * handle it too.
245 *
246 * "If the address is the IPv6 unspecified address ( "::" ),
247 * a lookup shall not be performed and the behavior shall be
248 * the same as when the node's name cannot be located."
249 * => getipnodebyaddr() handles this case for us.
250 * => in case of NI_NUMERICHOST being set,
251 * ip6_parsenumeric() -> inet_ntop[6] will handle it too.
252 */
253
254 /*
255 * We used to exclude link-local from lookups.
256 * Even though calles in the resolver chain may not (yet)
257 * properly deal with them, we no longer do as for link-local
258 * there is a path to resolve these. See:
259 * RFC 6303 4.5. IPv6 Link-Local Addresses
260 * RFC 6762 4. Reverse Address Mapping
261 *
262 * XXX For IPv6 MC the only reference found was
263 * https://www.ietf.org/archive/id/draft-michaelson-as112-ipv6-02.html
264 * but there are also no "empty zone"s for x.0.f.f.ip6.arpa
265 * in DNS servers. Keep catching it here for now and
266 * do not attempt name resolution but return the address string.
267 */
268 if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr))
269 flags |= NI_NUMERICHOST;
270 }
271 break;
272 #endif
273 }
274 if (host == NULL || hostlen == 0) {
275 /*
276 * do nothing in this case.
277 * in case you are wondering if "&&" is more correct than
278 * "||" here: rfc2553bis-03 says that host == NULL or
279 * hostlen == 0 means that the caller does not want the result.
280 */
281 } else if (flags & NI_NUMERICHOST) {
282 size_t numaddrlen;
283
284 /* NUMERICHOST and NAMEREQD conflicts with each other */
285 if (flags & NI_NAMEREQD)
286 return EAI_NONAME;
287
288 switch(afd->a_af) {
289 #ifdef INET6
290 case AF_INET6:
291 {
292 int error;
293
294 if ((error = ip6_parsenumeric(sa, addr, host,
295 hostlen, flags)) != 0)
296 return(error);
297 break;
298 }
299 #endif
300 default:
301 if (inet_ntop(afd->a_af, addr, numaddr, sizeof(numaddr))
302 == NULL)
303 return EAI_SYSTEM;
304 numaddrlen = strlen(numaddr);
305 if (numaddrlen + 1 > hostlen) /* don't forget terminator */
306 return EAI_MEMORY;
307 strlcpy(host, numaddr, hostlen);
308 break;
309 }
310 } else {
311 hp = getipnodebyaddr(addr, afd->a_addrlen, afd->a_af, &h_error);
312
313 if (hp) {
314 #if 0
315 /*
316 * commented out, since "for local host" is not
317 * implemented here - see RFC2553 p30
318 */
319 if (flags & NI_NOFQDN) {
320 char *p;
321 p = strchr(hp->h_name, '.');
322 if (p)
323 *p = '\0';
324 }
325 #endif
326 if (strlen(hp->h_name) + 1 > hostlen) {
327 freehostent(hp);
328 return EAI_MEMORY;
329 }
330 strlcpy(host, hp->h_name, hostlen);
331 freehostent(hp);
332 } else {
333 if (flags & NI_NAMEREQD)
334 return EAI_NONAME;
335 switch(afd->a_af) {
336 #ifdef INET6
337 case AF_INET6:
338 {
339 int error;
340
341 if ((error = ip6_parsenumeric(sa, addr, host,
342 hostlen,
343 flags)) != 0)
344 return(error);
345 break;
346 }
347 #endif
348 default:
349 if (inet_ntop(afd->a_af, addr, host,
350 hostlen) == NULL)
351 return EAI_SYSTEM;
352 break;
353 }
354 }
355 }
356 return(0);
357 }
358
359 #ifdef INET6
360 static int
ip6_parsenumeric(const struct sockaddr * sa,const char * addr,char * host,size_t hostlen,int flags)361 ip6_parsenumeric(const struct sockaddr *sa, const char *addr,
362 char *host, size_t hostlen, int flags)
363 {
364 size_t numaddrlen;
365 char numaddr[512];
366
367 if (inet_ntop(AF_INET6, addr, numaddr, sizeof(numaddr)) == NULL)
368 return EAI_SYSTEM;
369
370 numaddrlen = strlen(numaddr);
371 if (numaddrlen + 1 > hostlen) /* don't forget terminator */
372 return EAI_OVERFLOW;
373 strlcpy(host, numaddr, hostlen);
374
375 if (((const struct sockaddr_in6 *)sa)->sin6_scope_id) {
376 char zonebuf[MAXHOSTNAMELEN];
377 int zonelen;
378
379 zonelen = ip6_sa2str(
380 (const struct sockaddr_in6 *)(const void *)sa,
381 zonebuf, sizeof(zonebuf), flags);
382 if (zonelen < 0)
383 return EAI_OVERFLOW;
384 if (zonelen + 1 + numaddrlen + 1 > hostlen)
385 return EAI_OVERFLOW;
386
387 /* construct <numeric-addr><delim><zoneid> */
388 memcpy(host + numaddrlen + 1, zonebuf,
389 (size_t)zonelen);
390 host[numaddrlen] = SCOPE_DELIMITER;
391 host[numaddrlen + 1 + zonelen] = '\0';
392 }
393
394 return 0;
395 }
396
397 /* ARGSUSED */
398 static int
ip6_sa2str(const struct sockaddr_in6 * sa6,char * buf,size_t bufsiz,int flags)399 ip6_sa2str(const struct sockaddr_in6 *sa6, char *buf, size_t bufsiz, int flags)
400 {
401 unsigned int ifindex;
402 const struct in6_addr *a6;
403 int n;
404
405 ifindex = (unsigned int)sa6->sin6_scope_id;
406 a6 = &sa6->sin6_addr;
407
408 if ((flags & NI_NUMERICSCOPE) != 0) {
409 n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id);
410 if (n < 0 || n >= bufsiz)
411 return -1;
412 else
413 return n;
414 }
415
416 /* if_indextoname() does not take buffer size. not a good api... */
417 if ((IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6) ||
418 IN6_IS_ADDR_MC_NODELOCAL(a6)) && bufsiz >= IF_NAMESIZE) {
419 char *p = if_indextoname(ifindex, buf);
420 if (p) {
421 return(strlen(p));
422 }
423 }
424
425 /* last resort */
426 n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id);
427 if (n < 0 || (size_t)n >= bufsiz)
428 return -1;
429 else
430 return n;
431 }
432 #endif /* INET6 */
433
434 /*
435 * getnameinfo_link():
436 * Format a link-layer address into a printable format, paying attention to
437 * the interface type.
438 */
439 /* ARGSUSED */
440 static int
getnameinfo_link(const struct afd * afd,const struct sockaddr * sa,socklen_t salen,char * host,size_t hostlen,char * serv,size_t servlen,int flags)441 getnameinfo_link(const struct afd *afd,
442 const struct sockaddr *sa, socklen_t salen,
443 char *host, size_t hostlen, char *serv, size_t servlen, int flags)
444 {
445 const struct sockaddr_dl *sdl =
446 (const struct sockaddr_dl *)(const void *)sa;
447 const struct fw_hwaddr *iha;
448 int n;
449
450 if (serv != NULL && servlen > 0)
451 *serv = '\0';
452
453 if (sdl->sdl_nlen == 0 && sdl->sdl_alen == 0 && sdl->sdl_slen == 0) {
454 n = snprintf(host, hostlen, "link#%d", sdl->sdl_index);
455 if (n >= hostlen) {
456 *host = '\0';
457 return (EAI_MEMORY);
458 }
459 return (0);
460 }
461
462 if (sdl->sdl_nlen > 0 && sdl->sdl_alen == 0) {
463 n = sdl->sdl_nlen;
464 if (n >= hostlen) {
465 *host = '\0';
466 return (EAI_MEMORY);
467 }
468 memcpy(host, sdl->sdl_data, sdl->sdl_nlen);
469 host[n] = '\0';
470 return (0);
471 }
472
473 switch (sdl->sdl_type) {
474 case IFT_IEEE1394:
475 if (sdl->sdl_alen < sizeof(iha->sender_unique_ID_hi) +
476 sizeof(iha->sender_unique_ID_lo))
477 return EAI_FAMILY;
478 iha = (const struct fw_hwaddr *)(const void *)LLADDR(sdl);
479 return hexname((const u_int8_t *)&iha->sender_unique_ID_hi,
480 sizeof(iha->sender_unique_ID_hi) +
481 sizeof(iha->sender_unique_ID_lo),
482 host, hostlen);
483 /*
484 * The following have zero-length addresses.
485 * IFT_GIF (net/if_gif.c)
486 * IFT_LOOP (net/if_loop.c)
487 * IFT_PPP (net/if_tuntap.c)
488 * IFT_SLIP (net/if_sl.c, net/if_strip.c)
489 * IFT_STF (net/if_stf.c)
490 * IFT_L2VLAN (net/if_vlan.c)
491 * IFT_BRIDGE (net/if_bridge.h>
492 */
493 /*
494 * The following use IPv4 addresses as link-layer addresses:
495 * IFT_OTHER (net/if_gre.c)
496 * IFT_OTHER (netinet/ip_ipip.c)
497 */
498 /* default below is believed correct for all these. */
499 case IFT_ETHER:
500 case IFT_FDDI:
501 case IFT_HIPPI:
502 case IFT_ISO88025:
503 default:
504 return hexname((u_int8_t *)LLADDR(sdl), (size_t)sdl->sdl_alen,
505 host, hostlen);
506 }
507 }
508
509 static int
hexname(const u_int8_t * cp,size_t len,char * host,size_t hostlen)510 hexname(const u_int8_t *cp, size_t len, char *host, size_t hostlen)
511 {
512 int i, n;
513 char *outp = host;
514
515 *outp = '\0';
516 for (i = 0; i < len; i++) {
517 n = snprintf(outp, hostlen, "%s%02x",
518 i ? ":" : "", cp[i]);
519 if (n < 0 || n >= hostlen) {
520 *host = '\0';
521 return EAI_MEMORY;
522 }
523 outp += n;
524 hostlen -= n;
525 }
526 return 0;
527 }
528
529 /*
530 * getnameinfo_un():
531 * Format a UNIX IPC domain address (pathname).
532 */
533 /* ARGSUSED */
534 static int
getnameinfo_un(const struct afd * afd,const struct sockaddr * sa,socklen_t salen,char * host,size_t hostlen,char * serv,size_t servlen,int flags)535 getnameinfo_un(const struct afd *afd,
536 const struct sockaddr *sa, socklen_t salen,
537 char *host, size_t hostlen, char *serv, size_t servlen, int flags)
538 {
539 size_t pathlen;
540
541 if (serv != NULL && servlen > 0)
542 *serv = '\0';
543 if (host != NULL && hostlen > 0) {
544 pathlen = salen - afd->a_off;
545
546 if (pathlen + 1 > hostlen) {
547 *host = '\0';
548 return (EAI_MEMORY);
549 }
550 strlcpy(host, (const char *)sa + afd->a_off, pathlen + 1);
551 }
552
553 return (0);
554 }
555