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