1 /* $FreeBSD: src/lib/libc/net/getnameinfo.c,v 1.20 2007/02/28 21:18:38 bms Exp $ */
2 /* $KAME: getnameinfo.c,v 1.61 2002/06/27 09:25:47 itojun Exp $ */
3
4 /*
5 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
6 * Copyright (c) 2000 Ben Harris.
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/types.h>
49 #include <sys/socket.h>
50 #include <net/if.h>
51 #include <net/if_dl.h>
52 #include <net/if_types.h>
53 #include <netinet/in.h>
54 #include <arpa/inet.h>
55 #include <arpa/nameser.h>
56 #include <netdb.h>
57 #include <resolv.h>
58 #include <string.h>
59 #include <stddef.h>
60 #include <errno.h>
61
62 static int getnameinfo_inet(const struct sockaddr *, socklen_t, char *,
63 size_t, char *, size_t, int);
64 #ifdef INET6
65 static int ip6_parsenumeric(const struct sockaddr *, const char *, char *,
66 size_t, int);
67 static int ip6_sa2str(const struct sockaddr_in6 *, char *, size_t, int);
68 #endif
69 static int getnameinfo_link(const struct sockaddr *, socklen_t, char *,
70 size_t, char *, size_t, int);
71 static int hexname(const u_int8_t *, size_t, char *, size_t);
72
73 int
getnameinfo(const struct sockaddr * __restrict sa,socklen_t salen,char * __restrict host,size_t hostlen,char * __restrict serv,size_t servlen,int flags)74 getnameinfo(const struct sockaddr * __restrict sa, socklen_t salen,
75 char * __restrict host, size_t hostlen, char * __restrict serv,
76 size_t servlen, int flags)
77 {
78
79 switch (sa->sa_family) {
80 case AF_INET:
81 #ifdef INET6
82 case AF_INET6:
83 #endif
84 return getnameinfo_inet(sa, salen, host, hostlen, serv,
85 servlen, flags);
86 case AF_LINK:
87 return getnameinfo_link(sa, salen, host, hostlen, serv,
88 servlen, flags);
89 default:
90 return EAI_FAMILY;
91 }
92 }
93
94 static const struct afd {
95 int a_af;
96 size_t a_addrlen;
97 socklen_t a_socklen;
98 int a_off;
99 } afdl [] = {
100 #ifdef INET6
101 {PF_INET6, sizeof(struct in6_addr), sizeof(struct sockaddr_in6),
102 offsetof(struct sockaddr_in6, sin6_addr)},
103 #endif
104 {PF_INET, sizeof(struct in_addr), sizeof(struct sockaddr_in),
105 offsetof(struct sockaddr_in, sin_addr)},
106 { .a_af = 0 },
107 };
108
109 struct sockinet {
110 u_char si_len;
111 u_char si_family;
112 u_short si_port;
113 };
114
115 static int
getnameinfo_inet(const struct sockaddr * sa,socklen_t salen,char * host,size_t hostlen,char * serv,size_t servlen,int flags)116 getnameinfo_inet(const struct sockaddr *sa, socklen_t salen, char *host,
117 size_t hostlen, char *serv, size_t servlen, int flags)
118 {
119 const struct afd *afd;
120 struct servent *sp;
121 struct hostent *hp;
122 u_short port;
123 int family, i;
124 const char *addr;
125 u_int32_t v4a;
126 int h_error;
127 char numserv[512];
128 char numaddr[512];
129
130 if (sa == NULL)
131 return EAI_FAIL;
132
133 family = sa->sa_family;
134 for (i = 0; afdl[i].a_af; i++)
135 if (afdl[i].a_af == family) {
136 afd = &afdl[i];
137 goto found;
138 }
139 return EAI_FAMILY;
140
141 found:
142 if (salen != afd->a_socklen)
143 return EAI_FAIL;
144
145 /* network byte order */
146 port = ((const struct sockinet *)sa)->si_port;
147 addr = (const char *)sa + afd->a_off;
148
149 if (serv == NULL || servlen == 0) {
150 /*
151 * do nothing in this case.
152 * in case you are wondering if "&&" is more correct than
153 * "||" here: rfc2553bis-03 says that serv == NULL OR
154 * servlen == 0 means that the caller does not want the result.
155 */
156 } else {
157 if (flags & NI_NUMERICSERV)
158 sp = NULL;
159 else {
160 sp = getservbyport(port,
161 (flags & NI_DGRAM) ? "udp" : "tcp");
162 }
163 if (sp) {
164 if (strlen(sp->s_name) + 1 > servlen)
165 return EAI_MEMORY;
166 strlcpy(serv, sp->s_name, servlen);
167 } else {
168 snprintf(numserv, sizeof(numserv), "%u", ntohs(port));
169 if (strlen(numserv) + 1 > servlen)
170 return EAI_MEMORY;
171 strlcpy(serv, numserv, servlen);
172 }
173 }
174
175 switch (sa->sa_family) {
176 case AF_INET:
177 v4a = (u_int32_t)
178 ntohl(((const struct sockaddr_in *)sa)->sin_addr.s_addr);
179 if (IN_MULTICAST(v4a) || IN_EXPERIMENTAL(v4a))
180 flags |= NI_NUMERICHOST;
181 v4a >>= IN_CLASSA_NSHIFT;
182 if (v4a == 0)
183 flags |= NI_NUMERICHOST;
184 break;
185 #ifdef INET6
186 case AF_INET6:
187 {
188 const struct sockaddr_in6 *sin6;
189 sin6 = (const struct sockaddr_in6 *)sa;
190 switch (sin6->sin6_addr.s6_addr[0]) {
191 case 0x00:
192 if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr))
193 ;
194 else if (IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr))
195 ;
196 else
197 flags |= NI_NUMERICHOST;
198 break;
199 default:
200 if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr)) {
201 flags |= NI_NUMERICHOST;
202 }
203 else if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr))
204 flags |= NI_NUMERICHOST;
205 break;
206 }
207 }
208 break;
209 #endif
210 }
211 if (host == NULL || hostlen == 0) {
212 /*
213 * do nothing in this case.
214 * in case you are wondering if "&&" is more correct than
215 * "||" here: rfc2553bis-03 says that host == NULL or
216 * hostlen == 0 means that the caller does not want the result.
217 */
218 } else if (flags & NI_NUMERICHOST) {
219 size_t numaddrlen;
220
221 /* NUMERICHOST and NAMEREQD conflicts with each other */
222 if (flags & NI_NAMEREQD)
223 return EAI_NONAME;
224
225 switch(afd->a_af) {
226 #ifdef INET6
227 case AF_INET6:
228 {
229 int error;
230
231 if ((error = ip6_parsenumeric(sa, addr, host,
232 hostlen, flags)) != 0)
233 return(error);
234 break;
235 }
236 #endif
237 default:
238 if (inet_ntop(afd->a_af, addr, numaddr, sizeof(numaddr))
239 == NULL)
240 return EAI_SYSTEM;
241 numaddrlen = strlen(numaddr);
242 if (numaddrlen + 1 > hostlen) /* don't forget terminator */
243 return EAI_MEMORY;
244 strlcpy(host, numaddr, hostlen);
245 break;
246 }
247 } else {
248 hp = getipnodebyaddr(addr, afd->a_addrlen, afd->a_af, &h_error);
249
250 if (hp) {
251 #if 0
252 /*
253 * commented out, since "for local host" is not
254 * implemented here - see RFC2553 p30
255 */
256 if (flags & NI_NOFQDN) {
257 char *p;
258 p = strchr(hp->h_name, '.');
259 if (p)
260 *p = '\0';
261 }
262 #endif
263 if (strlen(hp->h_name) + 1 > hostlen) {
264 freehostent(hp);
265 return EAI_MEMORY;
266 }
267 strlcpy(host, hp->h_name, hostlen);
268 freehostent(hp);
269 } else {
270 if (flags & NI_NAMEREQD)
271 return EAI_NONAME;
272 switch(afd->a_af) {
273 #ifdef INET6
274 case AF_INET6:
275 {
276 int error;
277
278 if ((error = ip6_parsenumeric(sa, addr, host,
279 hostlen,
280 flags)) != 0)
281 return(error);
282 break;
283 }
284 #endif
285 default:
286 if (inet_ntop(afd->a_af, addr, host,
287 hostlen) == NULL)
288 return EAI_SYSTEM;
289 break;
290 }
291 }
292 }
293 return(0);
294 }
295
296 #ifdef INET6
297 static int
ip6_parsenumeric(const struct sockaddr * sa,const char * addr,char * host,size_t hostlen,int flags)298 ip6_parsenumeric(const struct sockaddr *sa, const char *addr, char *host,
299 size_t hostlen, int flags)
300 {
301 size_t numaddrlen;
302 char numaddr[512];
303
304 if (inet_ntop(AF_INET6, addr, numaddr, sizeof(numaddr)) == NULL)
305 return EAI_SYSTEM;
306
307 numaddrlen = strlen(numaddr);
308 if (numaddrlen + 1 > hostlen) /* don't forget terminator */
309 return EAI_OVERFLOW;
310 strlcpy(host, numaddr, hostlen);
311
312 if (((const struct sockaddr_in6 *)sa)->sin6_scope_id) {
313 char zonebuf[MAXHOSTNAMELEN];
314 int zonelen;
315
316 zonelen = ip6_sa2str(
317 (const struct sockaddr_in6 *)(const void *)sa,
318 zonebuf, sizeof(zonebuf), flags);
319 if (zonelen < 0)
320 return EAI_OVERFLOW;
321 if (zonelen + 1 + numaddrlen + 1 > hostlen)
322 return EAI_OVERFLOW;
323
324 /* construct <numeric-addr><delim><zoneid> */
325 memcpy(host + numaddrlen + 1, zonebuf,
326 (size_t)zonelen);
327 host[numaddrlen] = SCOPE_DELIMITER;
328 host[numaddrlen + 1 + zonelen] = '\0';
329 }
330
331 return 0;
332 }
333
334 /* ARGSUSED */
335 static int
ip6_sa2str(const struct sockaddr_in6 * sa6,char * buf,size_t bufsiz,int flags __unused)336 ip6_sa2str(const struct sockaddr_in6 *sa6, char *buf, size_t bufsiz,
337 int flags __unused)
338 {
339 unsigned int ifindex;
340 const struct in6_addr *a6;
341 int n;
342
343 ifindex = (unsigned int)sa6->sin6_scope_id;
344 a6 = &sa6->sin6_addr;
345
346 if ((flags & NI_NUMERICSCOPE) != 0) {
347 n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id);
348 if (n < 0 || n >= bufsiz)
349 return -1;
350 else
351 return n;
352 }
353
354 /* if_indextoname() does not take buffer size. not a good api... */
355 if ((IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6) ||
356 IN6_IS_ADDR_MC_NODELOCAL(a6)) && bufsiz >= IF_NAMESIZE) {
357 char *p = if_indextoname(ifindex, buf);
358 if (p) {
359 return(strlen(p));
360 }
361 }
362
363 /* last resort */
364 n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id);
365 if (n < 0 || (size_t)n >= bufsiz)
366 return -1;
367 else
368 return n;
369 }
370 #endif /* INET6 */
371
372 /*
373 * getnameinfo_link():
374 * Format a link-layer address into a printable format, paying attention to
375 * the interface type.
376 */
377 /* ARGSUSED */
378 static int
getnameinfo_link(const struct sockaddr * sa,socklen_t salen __unused,char * host,size_t hostlen,char * serv,size_t servlen,int flags __unused)379 getnameinfo_link(const struct sockaddr *sa, socklen_t salen __unused,
380 char *host, size_t hostlen, char *serv, size_t servlen,
381 int flags __unused)
382 {
383 const struct sockaddr_dl *sdl =
384 (const struct sockaddr_dl *)(const void *)sa;
385 int n;
386
387 if (serv != NULL && servlen > 0)
388 *serv = '\0';
389
390 if (sdl->sdl_nlen == 0 && sdl->sdl_alen == 0 && sdl->sdl_slen == 0) {
391 n = snprintf(host, hostlen, "link#%d", sdl->sdl_index);
392 if (n > hostlen) {
393 *host = '\0';
394 return EAI_MEMORY;
395 }
396 return 0;
397 }
398
399 switch (sdl->sdl_type) {
400 /*
401 * The following have zero-length addresses.
402 * IFT_GIF (net/gif/if_gif.c)
403 * IFT_LOOP (net/if_loop.c, net/disc/if_disc.c)
404 * IFT_PPP (net/sppp/if_spppsubr.c)
405 * IFT_SLIP (net/sl/if_sl.c)
406 * IFT_STF (net/stf/if_stf.c)
407 * IFT_L2VLAN (net/vlan/if_vlan.c)
408 * IFT_BRIDGE (net/bridge/if_bridge.c)
409 */
410 /*
411 * The following use IPv4 addresses as link-layer addresses:
412 * IFT_OTHER (net/gre/if_gre.c)
413 */
414 /* default below is believed correct for all these. */
415 case IFT_ARCNET:
416 case IFT_ETHER:
417 case IFT_FDDI:
418 case IFT_HIPPI:
419 case IFT_ISO88025:
420 default:
421 return hexname((u_int8_t *)LLADDR(sdl), (size_t)sdl->sdl_alen,
422 host, hostlen);
423 }
424 }
425
426 static int
hexname(const u_int8_t * cp,size_t len,char * host,size_t hostlen)427 hexname(const u_int8_t *cp, size_t len, char *host, size_t hostlen)
428 {
429 int i, n;
430 char *outp = host;
431
432 *outp = '\0';
433 for (i = 0; i < len; i++) {
434 n = snprintf(outp, hostlen, "%s%02x",
435 i ? ":" : "", cp[i]);
436 if (n < 0 || n >= hostlen) {
437 *host = '\0';
438 return EAI_MEMORY;
439 }
440 outp += n;
441 hostlen -= n;
442 }
443 return 0;
444 }
445