1 /* $NetBSD: getnameinfo.c,v 1.53 2012/09/26 23:13:00 christos 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 1.53 2012/09/26 23:13:00 christos Exp $");
51 #endif /* LIBC_SCCS and not lint */
52
53 #include <sys/types.h>
54 #include <sys/socket.h>
55 #include <sys/un.h>
56 #include <net/if.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 <assert.h>
62 #include <limits.h>
63 #include <netdb.h>
64 #include "arpa_nameser.h"
65 #include "resolv_private.h"
66 #include <sys/system_properties.h>
67 #include <stdlib.h>
68 #include <unistd.h>
69 #include <errno.h>
70 #define MIN(x,y) ((x) < (y) ? (x) : (y))
71 #include <stddef.h>
72 #include <string.h>
73
74 static const struct afd {
75 int a_af;
76 socklen_t a_addrlen;
77 socklen_t a_socklen;
78 int a_off;
79 } afdl [] = {
80 #ifdef INET6
81 {PF_INET6, sizeof(struct in6_addr), sizeof(struct sockaddr_in6),
82 offsetof(struct sockaddr_in6, sin6_addr)},
83 #endif
84 {PF_INET, sizeof(struct in_addr), sizeof(struct sockaddr_in),
85 offsetof(struct sockaddr_in, sin_addr)},
86 {0, 0, 0, 0},
87 };
88
89 struct sockinet {
90 u_char si_len;
91 u_char si_family;
92 u_short si_port;
93 };
94
95 static int getnameinfo_inet(const struct sockaddr *, socklen_t, char *,
96 socklen_t, char *, socklen_t, int, const char*, int);
97 #ifdef INET6
98 static int ip6_parsenumeric(const struct sockaddr *, const char *, char *,
99 socklen_t, int);
100 static int ip6_sa2str(const struct sockaddr_in6 *, char *, size_t, int);
101 #endif
102 static int getnameinfo_local(const struct sockaddr *, socklen_t, char *,
103 socklen_t, char *, socklen_t, int);
104
105 /*
106 * Top-level getnameinfo() code. Look at the address family, and pick an
107 * appropriate function to call.
108 */
getnameinfo(const struct sockaddr * sa,socklen_t salen,char * host,size_t hostlen,char * serv,size_t servlen,int flags)109 int getnameinfo(const struct sockaddr* sa, socklen_t salen, char* host, size_t hostlen, char* serv, size_t servlen, int flags)
110 {
111 return android_getnameinfoforiface(sa, salen, host, hostlen, serv, servlen, flags, NULL, 0);
112 }
113
android_getnameinfoforiface(const struct sockaddr * sa,socklen_t salen,char * host,size_t hostlen,char * serv,size_t servlen,int flags,const char * iface,int mark)114 int android_getnameinfoforiface(const struct sockaddr* sa, socklen_t salen, char* host, size_t hostlen, char* serv, size_t servlen, int flags, const char* iface, int mark)
115 {
116 switch (sa->sa_family) {
117 case AF_INET:
118 case AF_INET6:
119 return getnameinfo_inet(sa, salen, host, hostlen,
120 serv, servlen, flags, iface, mark);
121 case AF_LOCAL:
122 return getnameinfo_local(sa, salen, host, hostlen,
123 serv, servlen, flags);
124 default:
125 return EAI_FAMILY;
126 }
127 }
128
129 /*
130 * getnameinfo_local():
131 * Format an local address into a printable format.
132 */
133 /* ARGSUSED */
134 static int
getnameinfo_local(const struct sockaddr * sa,socklen_t salen,char * host,socklen_t hostlen,char * serv,socklen_t servlen,int flags)135 getnameinfo_local(const struct sockaddr *sa, socklen_t salen,
136 char *host, socklen_t hostlen, char *serv, socklen_t servlen,
137 int flags __attribute__((unused)))
138 {
139 const struct sockaddr_un *sun =
140 (const struct sockaddr_un *)(const void *)sa;
141
142 if (salen < (socklen_t) offsetof(struct sockaddr_un, sun_path)) {
143 return EAI_FAMILY;
144 }
145
146 if (serv != NULL && servlen > 0)
147 serv[0] = '\0';
148
149 if (host && hostlen > 0)
150 strlcpy(host, sun->sun_path,
151 MIN((socklen_t) sizeof(sun->sun_path) + 1, hostlen));
152
153 return 0;
154 }
155
156 /* On success length of the host name is returned. A return
157 * value of 0 means there's no host name associated with
158 * the address. On failure -1 is returned in which case
159 * normal execution flow shall continue. */
160 static int
android_gethostbyaddr_proxy(char * nameBuf,size_t nameBufLen,const void * addr,socklen_t addrLen,int addrFamily,const char * iface,int mark)161 android_gethostbyaddr_proxy(char* nameBuf, size_t nameBufLen, const void *addr, socklen_t addrLen, int addrFamily, const char* iface, int mark)
162 {
163 struct hostent *hostResult =
164 android_gethostbyaddrforiface_proxy(addr, addrLen, addrFamily, iface, mark);
165
166 if (hostResult == NULL) return 0;
167
168 int lengthResult = strlen(hostResult->h_name);
169
170 if (nameBuf) strncpy(nameBuf, hostResult->h_name, nameBufLen);
171 return lengthResult;
172 }
173
174 /*
175 * getnameinfo_inet():
176 * Format an IPv4 or IPv6 sockaddr into a printable string.
177 */
178 static int
getnameinfo_inet(const struct sockaddr * sa,socklen_t salen,char * host,socklen_t hostlen,char * serv,socklen_t servlen,int flags,const char * iface,int mark)179 getnameinfo_inet(const struct sockaddr* sa, socklen_t salen,
180 char *host, socklen_t hostlen,
181 char *serv, socklen_t servlen,
182 int flags, const char* iface, int mark)
183 {
184 const struct afd *afd;
185 struct servent *sp;
186 struct hostent *hp;
187 u_short port;
188 int family, i;
189 const char *addr;
190 uint32_t v4a;
191 char numserv[512];
192 char numaddr[512];
193
194 /* sa is checked below */
195 /* host may be NULL */
196 /* serv may be NULL */
197
198 if (sa == NULL)
199 return EAI_FAIL;
200
201 family = sa->sa_family;
202 for (i = 0; afdl[i].a_af; i++)
203 if (afdl[i].a_af == family) {
204 afd = &afdl[i];
205 goto found;
206 }
207 return EAI_FAMILY;
208
209 found:
210 // http://b/1889275: callers should be allowed to provide too much
211 // space, but not too little.
212 if (salen < afd->a_socklen) {
213 return EAI_FAMILY;
214 }
215
216 /* network byte order */
217 port = ((const struct sockinet *)(const void *)sa)->si_port;
218 addr = (const char *)(const void *)sa + afd->a_off;
219
220 if (serv == NULL || servlen == 0) {
221 /*
222 * do nothing in this case.
223 * in case you are wondering if "&&" is more correct than
224 * "||" here: rfc2553bis-03 says that serv == NULL OR
225 * servlen == 0 means that the caller does not want the result.
226 */
227 } else {
228 if (flags & NI_NUMERICSERV)
229 sp = NULL;
230 else {
231 sp = getservbyport(port,
232 (flags & NI_DGRAM) ? "udp" : "tcp");
233 }
234 if (sp) {
235 if (strlen(sp->s_name) + 1 > (size_t)servlen)
236 return EAI_MEMORY;
237 strlcpy(serv, sp->s_name, servlen);
238 } else {
239 snprintf(numserv, sizeof(numserv), "%u", ntohs(port));
240 if (strlen(numserv) + 1 > (size_t)servlen)
241 return EAI_MEMORY;
242 strlcpy(serv, numserv, servlen);
243 }
244 }
245
246 switch (sa->sa_family) {
247 case AF_INET:
248 v4a = (uint32_t)
249 ntohl(((const struct sockaddr_in *)
250 (const void *)sa)->sin_addr.s_addr);
251 if (IN_MULTICAST(v4a) || IN_EXPERIMENTAL(v4a))
252 flags |= NI_NUMERICHOST;
253 v4a >>= IN_CLASSA_NSHIFT;
254 if (v4a == 0)
255 flags |= NI_NUMERICHOST;
256 break;
257 #ifdef INET6
258 case AF_INET6:
259 {
260 const struct sockaddr_in6 *sin6;
261 sin6 = (const struct sockaddr_in6 *)(const void *)sa;
262 switch (sin6->sin6_addr.s6_addr[0]) {
263 case 0x00:
264 if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr))
265 ;
266 else if (IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr))
267 ;
268 else
269 flags |= NI_NUMERICHOST;
270 break;
271 default:
272 if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr)) {
273 flags |= NI_NUMERICHOST;
274 }
275 else if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr))
276 flags |= NI_NUMERICHOST;
277 break;
278 }
279 }
280 break;
281 #endif
282 }
283 if (host == NULL || hostlen == 0) {
284 /*
285 * do nothing in this case.
286 * in case you are wondering if "&&" is more correct than
287 * "||" here: rfc2553bis-03 says that host == NULL or
288 * hostlen == 0 means that the caller does not want the result.
289 */
290 } else if (flags & NI_NUMERICHOST) {
291 size_t numaddrlen;
292
293 /* NUMERICHOST and NAMEREQD conflicts with each other */
294 if (flags & NI_NAMEREQD)
295 return EAI_NONAME;
296
297 switch(afd->a_af) {
298 #ifdef INET6
299 case AF_INET6:
300 {
301 int error;
302
303 if ((error = ip6_parsenumeric(sa, addr, host,
304 hostlen, flags)) != 0)
305 return(error);
306 break;
307 }
308 #endif
309 default:
310 if (inet_ntop(afd->a_af, addr, numaddr, sizeof(numaddr))
311 == NULL)
312 return EAI_SYSTEM;
313 numaddrlen = strlen(numaddr);
314 if (numaddrlen + 1 > (size_t)hostlen) /* don't forget terminator */
315 return EAI_MEMORY;
316 strlcpy(host, numaddr, hostlen);
317 break;
318 }
319 } else {
320 struct hostent android_proxy_hostent;
321 char android_proxy_buf[MAXDNAME];
322
323 int hostnamelen = android_gethostbyaddr_proxy(android_proxy_buf,
324 MAXDNAME, addr, afd->a_addrlen, afd->a_af, iface, mark);
325 if (hostnamelen > 0) {
326 hp = &android_proxy_hostent;
327 hp->h_name = android_proxy_buf;
328 } else if (!hostnamelen) {
329 hp = NULL;
330 } else {
331 hp = android_gethostbyaddrforiface(addr, afd->a_addrlen, afd->a_af,
332 iface, mark);
333 }
334
335 if (hp) {
336 #if 0
337 /*
338 * commented out, since "for local host" is not
339 * implemented here - see RFC2553 p30
340 */
341 if (flags & NI_NOFQDN) {
342 char *p;
343 p = strchr(hp->h_name, '.');
344 if (p)
345 *p = '\0';
346 }
347 #endif
348 if (strlen(hp->h_name) + 1 > (size_t)hostlen) {
349 return EAI_MEMORY;
350 }
351 strlcpy(host, hp->h_name, hostlen);
352 } else {
353 if (flags & NI_NAMEREQD)
354 return EAI_NONAME;
355 switch(afd->a_af) {
356 #ifdef INET6
357 case AF_INET6:
358 {
359 int error;
360
361 if ((error = ip6_parsenumeric(sa, addr, host,
362 hostlen,
363 flags)) != 0)
364 return(error);
365 break;
366 }
367 #endif
368 default:
369 if (inet_ntop(afd->a_af, addr, host,
370 hostlen) == NULL)
371 return EAI_SYSTEM;
372 break;
373 }
374 }
375 }
376 return(0);
377 }
378
379 #ifdef INET6
380 static int
ip6_parsenumeric(const struct sockaddr * sa,const char * addr,char * host,socklen_t hostlen,int flags)381 ip6_parsenumeric(const struct sockaddr *sa, const char *addr, char *host,
382 socklen_t hostlen, int flags)
383 {
384 size_t numaddrlen;
385 char numaddr[512];
386
387 assert(sa != NULL);
388 assert(addr != NULL);
389 assert(host != NULL);
390
391 if (inet_ntop(AF_INET6, addr, numaddr, sizeof(numaddr)) == NULL)
392 return EAI_SYSTEM;
393
394 numaddrlen = strlen(numaddr);
395 if (numaddrlen + 1 > (size_t)hostlen) /* don't forget terminator */
396 return EAI_OVERFLOW;
397 strlcpy(host, numaddr, hostlen);
398
399 if (((const struct sockaddr_in6 *)(const void *)sa)->sin6_scope_id) {
400 char zonebuf[MAXHOSTNAMELEN];
401 int zonelen;
402
403 zonelen = ip6_sa2str(
404 (const struct sockaddr_in6 *)(const void *)sa,
405 zonebuf, sizeof(zonebuf), flags);
406 if (zonelen < 0)
407 return EAI_OVERFLOW;
408 if ((size_t) zonelen + 1 + numaddrlen + 1 > (size_t)hostlen)
409 return EAI_OVERFLOW;
410 /* construct <numeric-addr><delim><zoneid> */
411 memcpy(host + numaddrlen + 1, zonebuf,
412 (size_t)zonelen);
413 host[numaddrlen] = SCOPE_DELIMITER;
414 host[numaddrlen + 1 + zonelen] = '\0';
415 }
416
417 return 0;
418 }
419
420 /* ARGSUSED */
421 static int
ip6_sa2str(const struct sockaddr_in6 * sa6,char * buf,size_t bufsiz,int flags)422 ip6_sa2str(const struct sockaddr_in6 *sa6, char *buf, size_t bufsiz, int flags)
423 {
424 unsigned int ifindex;
425 const struct in6_addr *a6;
426 int n;
427
428 assert(sa6 != NULL);
429 assert(buf != NULL);
430
431 ifindex = (unsigned int)sa6->sin6_scope_id;
432 a6 = &sa6->sin6_addr;
433
434 #ifdef NI_NUMERICSCOPE
435 if ((flags & NI_NUMERICSCOPE) != 0) {
436 n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id);
437 if (n < 0 || n >= bufsiz)
438 return -1;
439 else
440 return n;
441 }
442 #endif
443
444 /* if_indextoname() does not take buffer size. not a good api... */
445 if ((IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6)) &&
446 bufsiz >= IF_NAMESIZE) {
447 char *p = if_indextoname(ifindex, buf);
448 if (p) {
449 return(strlen(p));
450 }
451 }
452
453 /* last resort */
454 n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id);
455 if (n < 0 || (size_t) n >= bufsiz)
456 return -1;
457 else
458 return n;
459 }
460 #endif /* INET6 */
461