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 <netinet/in.h>
58 #include <arpa/inet.h>
59 #include <assert.h>
60 #include <limits.h>
61 #include <netdb.h>
62 #include <arpa/nameser.h>
63 #include "resolv_netid.h"
64 #include "resolv_private.h"
65 #include <stdlib.h>
66 #include <unistd.h>
67 #include <errno.h>
68 #include <stddef.h>
69 #include <string.h>
70
71 #include "private/bionic_defs.h"
72
73 /* This macro is modelled after the ones in <netinet/in6.h>. */
74 /* RFC 6052, section 2.1 */
75 #define IN6_IS_ADDR_WKP(a) \
76 ((((a)->s6_addr32[0]) == ntohl(0x0064ff9b)) && \
77 (((a)->s6_addr32[1]) == 0) && \
78 (((a)->s6_addr32[2]) == 0))
79
80 static const struct afd {
81 int a_af;
82 socklen_t a_addrlen;
83 socklen_t a_socklen;
84 int a_off;
85 } afdl [] = {
86 #ifdef INET6
87 {PF_INET6, sizeof(struct in6_addr), sizeof(struct sockaddr_in6),
88 offsetof(struct sockaddr_in6, sin6_addr)},
89 #endif
90 {PF_INET, sizeof(struct in_addr), sizeof(struct sockaddr_in),
91 offsetof(struct sockaddr_in, sin_addr)},
92 {0, 0, 0, 0},
93 };
94
95 struct sockinet {
96 u_char si_len;
97 u_char si_family;
98 u_short si_port;
99 };
100
101 static int getnameinfo_inet(const struct sockaddr *, socklen_t, char *,
102 socklen_t, char *, socklen_t, int, unsigned, unsigned);
103 #ifdef INET6
104 static int ip6_parsenumeric(const struct sockaddr *, const char *, char *,
105 socklen_t, int);
106 static int ip6_sa2str(const struct sockaddr_in6 *, char *, size_t, int);
107 #endif
108 static int getnameinfo_local(const struct sockaddr *, socklen_t, char *,
109 socklen_t, char *, socklen_t, int);
110
111 /*
112 * Top-level getnameinfo() code. Look at the address family, and pick an
113 * appropriate function to call.
114 */
115 __BIONIC_WEAK_FOR_NATIVE_BRIDGE
getnameinfo(const struct sockaddr * sa,socklen_t salen,char * host,size_t hostlen,char * serv,size_t servlen,int flags)116 int getnameinfo(const struct sockaddr* sa, socklen_t salen, char* host, size_t hostlen,
117 char* serv, size_t servlen, int flags)
118 {
119 return android_getnameinfofornet(sa, salen, host, hostlen, serv, servlen, flags,
120 NETID_UNSET, MARK_UNSET);
121 }
122
android_getnameinfofornet(const struct sockaddr * sa,socklen_t salen,char * host,size_t hostlen,char * serv,size_t servlen,int flags,unsigned netid,unsigned mark)123 int android_getnameinfofornet(const struct sockaddr* sa, socklen_t salen, char* host,
124 size_t hostlen, char* serv, size_t servlen, int flags, unsigned netid,
125 unsigned mark)
126 {
127 switch (sa->sa_family) {
128 case AF_INET:
129 case AF_INET6:
130 return getnameinfo_inet(sa, salen, host, hostlen,
131 serv, servlen, flags, netid, mark);
132 case AF_LOCAL:
133 return getnameinfo_local(sa, salen, host, hostlen,
134 serv, servlen, flags);
135 default:
136 return EAI_FAMILY;
137 }
138 }
139
140 /*
141 * getnameinfo_local():
142 * Format an local address into a printable format.
143 */
144 /* ARGSUSED */
145 static int
getnameinfo_local(const struct sockaddr * sa,socklen_t salen,char * host,socklen_t hostlen,char * serv,socklen_t servlen,int flags)146 getnameinfo_local(const struct sockaddr *sa, socklen_t salen,
147 char *host, socklen_t hostlen, char *serv, socklen_t servlen,
148 int flags __attribute__((unused)))
149 {
150 const struct sockaddr_un *sun =
151 (const struct sockaddr_un *)(const void *)sa;
152
153 if (salen < (socklen_t) offsetof(struct sockaddr_un, sun_path)) {
154 return EAI_FAMILY;
155 }
156
157 if (serv != NULL && servlen > 0)
158 serv[0] = '\0';
159
160 if (host && hostlen > 0)
161 strlcpy(host, sun->sun_path,
162 MIN((socklen_t) sizeof(sun->sun_path) + 1, hostlen));
163
164 return 0;
165 }
166
167 /*
168 * getnameinfo_inet():
169 * Format an IPv4 or IPv6 sockaddr into a printable string.
170 */
171 static int
getnameinfo_inet(const struct sockaddr * sa,socklen_t salen,char * host,socklen_t hostlen,char * serv,socklen_t servlen,int flags,unsigned netid,unsigned mark)172 getnameinfo_inet(const struct sockaddr* sa, socklen_t salen,
173 char *host, socklen_t hostlen,
174 char *serv, socklen_t servlen,
175 int flags, unsigned netid, unsigned mark)
176 {
177 const struct afd *afd;
178 struct servent *sp;
179 struct hostent *hp;
180 u_short port;
181 int family, i;
182 const char *addr;
183 uint32_t v4a;
184 char numserv[512];
185 char numaddr[512];
186
187 /* sa is checked below */
188 /* host may be NULL */
189 /* serv may be NULL */
190
191 if (sa == NULL)
192 return EAI_FAIL;
193
194 family = sa->sa_family;
195 for (i = 0; afdl[i].a_af; i++)
196 if (afdl[i].a_af == family) {
197 afd = &afdl[i];
198 goto found;
199 }
200 return EAI_FAMILY;
201
202 found:
203 // http://b/1889275: callers should be allowed to provide too much
204 // space, but not too little.
205 if (salen < afd->a_socklen) {
206 return EAI_FAMILY;
207 }
208
209 /* network byte order */
210 port = ((const struct sockinet *)(const void *)sa)->si_port;
211 addr = (const char *)(const void *)sa + afd->a_off;
212
213 if (serv == NULL || servlen == 0) {
214 /*
215 * do nothing in this case.
216 * in case you are wondering if "&&" is more correct than
217 * "||" here: rfc2553bis-03 says that serv == NULL OR
218 * servlen == 0 means that the caller does not want the result.
219 */
220 } else {
221 if (flags & NI_NUMERICSERV)
222 sp = NULL;
223 else {
224 sp = getservbyport(port,
225 (flags & NI_DGRAM) ? "udp" : "tcp");
226 }
227 if (sp) {
228 if (strlen(sp->s_name) + 1 > (size_t)servlen)
229 return EAI_MEMORY;
230 strlcpy(serv, sp->s_name, servlen);
231 } else {
232 snprintf(numserv, sizeof(numserv), "%u", ntohs(port));
233 if (strlen(numserv) + 1 > (size_t)servlen)
234 return EAI_MEMORY;
235 strlcpy(serv, numserv, servlen);
236 }
237 }
238
239 switch (sa->sa_family) {
240 case AF_INET:
241 v4a = (uint32_t)
242 ntohl(((const struct sockaddr_in *)
243 (const void *)sa)->sin_addr.s_addr);
244 if (IN_MULTICAST(v4a) || IN_EXPERIMENTAL(v4a))
245 flags |= NI_NUMERICHOST;
246 v4a >>= IN_CLASSA_NSHIFT;
247 if (v4a == 0)
248 flags |= NI_NUMERICHOST;
249 break;
250 #ifdef INET6
251 case AF_INET6:
252 {
253 const struct sockaddr_in6 *sin6;
254 sin6 = (const struct sockaddr_in6 *)(const void *)sa;
255 switch (sin6->sin6_addr.s6_addr[0]) {
256 case 0x00:
257 if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr))
258 ;
259 else if (IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr))
260 ;
261 else if (IN6_IS_ADDR_WKP(&sin6->sin6_addr))
262 ;
263 else
264 flags |= NI_NUMERICHOST;
265 break;
266 default:
267 if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr)) {
268 flags |= NI_NUMERICHOST;
269 }
270 else if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr))
271 flags |= NI_NUMERICHOST;
272 break;
273 }
274 }
275 break;
276 #endif
277 }
278 if (host == NULL || hostlen == 0) {
279 /*
280 * do nothing in this case.
281 * in case you are wondering if "&&" is more correct than
282 * "||" here: rfc2553bis-03 says that host == NULL or
283 * hostlen == 0 means that the caller does not want the result.
284 */
285 } else if (flags & NI_NUMERICHOST) {
286 size_t numaddrlen;
287
288 /* NUMERICHOST and NAMEREQD conflicts with each other */
289 if (flags & NI_NAMEREQD)
290 return EAI_NONAME;
291
292 switch(afd->a_af) {
293 #ifdef INET6
294 case AF_INET6:
295 {
296 int error;
297
298 if ((error = ip6_parsenumeric(sa, addr, host,
299 hostlen, flags)) != 0)
300 return(error);
301 break;
302 }
303 #endif
304 default:
305 if (inet_ntop(afd->a_af, addr, numaddr, sizeof(numaddr))
306 == NULL)
307 return EAI_SYSTEM;
308 numaddrlen = strlen(numaddr);
309 if (numaddrlen + 1 > (size_t)hostlen) /* don't forget terminator */
310 return EAI_MEMORY;
311 strlcpy(host, numaddr, hostlen);
312 break;
313 }
314 } else {
315 // This code should only run in the app context, not inside netd, so netid is
316 // the app's netid. netd doesn't use getnameinfo for network requests.
317 const struct android_net_context netcontext = { .app_netid = netid, .app_mark = mark };
318 hp = android_gethostbyaddrfornetcontext_proxy(addr, afd->a_addrlen, afd->a_af, &netcontext);
319 if (hp) {
320 #if 0
321 /*
322 * commented out, since "for local host" is not
323 * implemented here - see RFC2553 p30
324 */
325 if (flags & NI_NOFQDN) {
326 char *p;
327 p = strchr(hp->h_name, '.');
328 if (p)
329 TODO: Before uncommenting rewrite to avoid modifying hp.
330 *p = '\0';
331 }
332 #endif
333 if (strlen(hp->h_name) + 1 > (size_t)hostlen) {
334 return EAI_MEMORY;
335 }
336 strlcpy(host, hp->h_name, hostlen);
337 } else {
338 if (flags & NI_NAMEREQD)
339 return EAI_NONAME;
340 switch(afd->a_af) {
341 #ifdef INET6
342 case AF_INET6:
343 {
344 int error;
345
346 if ((error = ip6_parsenumeric(sa, addr, host,
347 hostlen,
348 flags)) != 0)
349 return(error);
350 break;
351 }
352 #endif
353 default:
354 if (inet_ntop(afd->a_af, addr, host,
355 hostlen) == NULL)
356 return EAI_SYSTEM;
357 break;
358 }
359 }
360 }
361 return(0);
362 }
363
364 #ifdef INET6
365 static int
ip6_parsenumeric(const struct sockaddr * sa,const char * addr,char * host,socklen_t hostlen,int flags)366 ip6_parsenumeric(const struct sockaddr *sa, const char *addr, char *host,
367 socklen_t hostlen, int flags)
368 {
369 size_t numaddrlen;
370 char numaddr[512];
371
372 assert(sa != NULL);
373 assert(addr != NULL);
374 assert(host != NULL);
375
376 if (inet_ntop(AF_INET6, addr, numaddr, sizeof(numaddr)) == NULL)
377 return EAI_SYSTEM;
378
379 numaddrlen = strlen(numaddr);
380 if (numaddrlen + 1 > (size_t)hostlen) /* don't forget terminator */
381 return EAI_OVERFLOW;
382 strlcpy(host, numaddr, hostlen);
383
384 if (((const struct sockaddr_in6 *)(const void *)sa)->sin6_scope_id) {
385 char zonebuf[MAXHOSTNAMELEN];
386 int zonelen;
387
388 zonelen = ip6_sa2str(
389 (const struct sockaddr_in6 *)(const void *)sa,
390 zonebuf, sizeof(zonebuf), flags);
391 if (zonelen < 0)
392 return EAI_OVERFLOW;
393 if ((size_t) zonelen + 1 + numaddrlen + 1 > (size_t)hostlen)
394 return EAI_OVERFLOW;
395 /* construct <numeric-addr><delim><zoneid> */
396 memcpy(host + numaddrlen + 1, zonebuf,
397 (size_t)zonelen);
398 host[numaddrlen] = SCOPE_DELIMITER;
399 host[numaddrlen + 1 + zonelen] = '\0';
400 }
401
402 return 0;
403 }
404
405 /* ARGSUSED */
406 static int
ip6_sa2str(const struct sockaddr_in6 * sa6,char * buf,size_t bufsiz,int flags)407 ip6_sa2str(const struct sockaddr_in6 *sa6, char *buf, size_t bufsiz, int flags)
408 {
409 unsigned int ifindex;
410 const struct in6_addr *a6;
411 int n;
412
413 assert(sa6 != NULL);
414 assert(buf != NULL);
415
416 ifindex = (unsigned int)sa6->sin6_scope_id;
417 a6 = &sa6->sin6_addr;
418
419 #ifdef NI_NUMERICSCOPE
420 if ((flags & NI_NUMERICSCOPE) != 0) {
421 n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id);
422 if (n < 0 || n >= bufsiz)
423 return -1;
424 else
425 return n;
426 }
427 #endif
428
429 /* if_indextoname() does not take buffer size. not a good api... */
430 if ((IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6)) &&
431 bufsiz >= IF_NAMESIZE) {
432 char *p = if_indextoname(ifindex, buf);
433 if (p) {
434 return(strlen(p));
435 }
436 }
437
438 /* last resort */
439 n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id);
440 if (n < 0 || (size_t) n >= bufsiz)
441 return -1;
442 else
443 return n;
444 }
445 #endif /* INET6 */
446