1 /* $NetBSD: getnameinfo.c,v 1.7 2014/12/10 04:38:02 christos Exp $ */
2
3 /*
4 * Portions Copyright (C) 2004, 2005, 2007, 2011-2013 Internet Systems Consortium, Inc. ("ISC")
5 * Portions Copyright (C) 1999-2001, 2003 Internet Software Consortium.
6 *
7 * Permission to use, copy, modify, and/or distribute this software for any
8 * purpose with or without fee is hereby granted, provided that the above
9 * copyright notice and this permission notice appear in all copies.
10 *
11 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
12 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
13 * AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
14 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
15 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
16 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
17 * PERFORMANCE OF THIS SOFTWARE.
18 */
19
20 /* Id */
21
22 /*! \file */
23
24 /*
25 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
26 * All rights reserved.
27 *
28 * Redistribution and use in source and binary forms, with or without
29 * modification, are permitted provided that the following conditions
30 * are met:
31 * 1. Redistributions of source code must retain the above copyright
32 * notice, this list of conditions and the following disclaimer.
33 * 2. Redistributions in binary form must reproduce the above copyright
34 * notice, this list of conditions and the following disclaimer in the
35 * documentation and/or other materials provided with the distribution.
36 * 3. Neither the name of the project nor the names of its contributors
37 * may be used to endorse or promote products derived from this software
38 * without specific prior written permission.
39 *
40 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
41 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
42 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
43 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
44 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
45 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
46 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
48 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
49 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
50 * SUCH DAMAGE.
51 */
52
53 /*
54 * XXX
55 * Issues to be discussed:
56 * - Return values. There seems to be no standard for return value (RFC2553)
57 * but INRIA implementation returns EAI_xxx defined for getaddrinfo().
58 */
59
60
61 /**
62 * This function is equivalent to the getnameinfo(3) function defined in
63 * RFC2133. lwres_getnameinfo() returns the hostname for the struct
64 * sockaddr sa which is salen bytes long. The hostname is of length
65 * hostlen and is returned via *host. The maximum length of the hostname
66 * is 1025 bytes: #NI_MAXHOST.
67 *
68 * The name of the service associated with the port number in sa is
69 * returned in *serv. It is servlen bytes long. The maximum length of the
70 * service name is #NI_MAXSERV - 32 bytes.
71 *
72 * The flags argument sets the following bits:
73 *
74 * \li #NI_NOFQDN:
75 * A fully qualified domain name is not required for local hosts.
76 * The local part of the fully qualified domain name is returned
77 * instead.
78 *
79 * \li #NI_NUMERICHOST
80 * Return the address in numeric form, as if calling inet_ntop(),
81 * instead of a host name.
82 *
83 * \li #NI_NAMEREQD
84 * A name is required. If the hostname cannot be found in the DNS
85 * and this flag is set, a non-zero error code is returned. If the
86 * hostname is not found and the flag is not set, the address is
87 * returned in numeric form.
88 *
89 * \li #NI_NUMERICSERV
90 * The service name is returned as a digit string representing the
91 * port number.
92 *
93 * \li #NI_DGRAM
94 * Specifies that the service being looked up is a datagram
95 * service, and causes getservbyport() to be called with a second
96 * argument of "udp" instead of its default of "tcp". This is
97 * required for the few ports (512-514) that have different
98 * services for UDP and TCP.
99 *
100 * \section getnameinfo_return Return Values
101 *
102 * lwres_getnameinfo() returns 0 on success or a non-zero error code if
103 * an error occurs.
104 *
105 * \section getname_see See Also
106 *
107 * RFC2133, getservbyport(),
108 * lwres_getnamebyaddr(). lwres_net_ntop().
109 *
110 * \section getnameinfo_bugs Bugs
111 *
112 * RFC2133 fails to define what the nonzero return values of
113 * getnameinfo() are.
114 */
115
116 #include <config.h>
117
118 #include <stdio.h>
119 #include <string.h>
120
121 #include <lwres/lwres.h>
122 #include <lwres/net.h>
123 #include <lwres/netdb.h>
124 #include "print_p.h"
125
126 #include "assert_p.h"
127
128 #define SUCCESS 0
129
130 /*% afd structure definition */
131 static struct afd {
132 int a_af;
133 size_t a_addrlen;
134 size_t a_socklen;
135 } afdl [] = {
136 /*!
137 * First entry is linked last...
138 */
139 { AF_INET, sizeof(struct in_addr), sizeof(struct sockaddr_in) },
140 { AF_INET6, sizeof(struct in6_addr), sizeof(struct sockaddr_in6) },
141 {0, 0, 0},
142 };
143
144 #define ENI_NOSERVNAME 1
145 #define ENI_NOHOSTNAME 2
146 #define ENI_MEMORY 3
147 #define ENI_SYSTEM 4
148 #define ENI_FAMILY 5
149 #define ENI_SALEN 6
150 #define ENI_NOSOCKET 7
151
152 /*!
153 * The test against 0 is there to keep the Solaris compiler
154 * from complaining about "end-of-loop code not reached".
155 */
156 #define ERR(code) \
157 do { result = (code); \
158 goto cleanup; \
159 } while (/*CONSTCOND*/0)
160
161 /*% lightweight resolver socket address structure to hostname and service name */
162 int
lwres_getnameinfo(const struct sockaddr * sa,size_t salen,char * host,size_t hostlen,char * serv,size_t servlen,int flags)163 lwres_getnameinfo(const struct sockaddr *sa, size_t salen, char *host,
164 size_t hostlen, char *serv, size_t servlen, int flags)
165 {
166 struct afd *afd = NULL;
167 struct servent *sp;
168 unsigned short port;
169 #ifdef LWRES_PLATFORM_HAVESALEN
170 size_t len;
171 #endif
172 int family, i;
173 const void *addr;
174 char *p;
175 #if 0
176 unsigned long v4a;
177 unsigned char pfx;
178 #endif
179 char numserv[sizeof("65000")];
180 char numaddr[sizeof("abcd:abcd:abcd:abcd:abcd:abcd:255.255.255.255")
181 + 1 + sizeof("4294967295")];
182 const char *proto;
183 lwres_uint32_t lwf = 0;
184 lwres_context_t *lwrctx = NULL;
185 lwres_gnbaresponse_t *by = NULL;
186 int result = SUCCESS;
187 int n;
188
189 if (sa == NULL)
190 ERR(ENI_NOSOCKET);
191
192 #ifdef LWRES_PLATFORM_HAVESALEN
193 len = sa->sa_len;
194 if (len != salen)
195 ERR(ENI_SALEN);
196 #endif
197
198 family = sa->sa_family;
199 for (i = 0; afdl[i].a_af; i++)
200 if (afdl[i].a_af == family) {
201 afd = &afdl[i];
202 goto found;
203 }
204 ERR(ENI_FAMILY);
205
206 found:
207 if (salen != afd->a_socklen)
208 ERR(ENI_SALEN);
209
210 switch (family) {
211 case AF_INET:
212 port = ((const struct sockaddr_in *)sa)->sin_port;
213 addr = &((const struct sockaddr_in *)sa)->sin_addr.s_addr;
214 break;
215
216 case AF_INET6:
217 port = ((const struct sockaddr_in6 *)sa)->sin6_port;
218 addr = ((const struct sockaddr_in6 *)sa)->sin6_addr.s6_addr;
219 break;
220
221 default:
222 port = 0;
223 addr = NULL;
224 POST(port); POST(addr);
225 INSIST(0);
226 }
227 proto = (flags & NI_DGRAM) ? "udp" : "tcp";
228
229 if (serv == NULL || servlen == 0U) {
230 /*
231 * Caller does not want service.
232 */
233 } else if ((flags & NI_NUMERICSERV) != 0 ||
234 (sp = getservbyport(port, proto)) == NULL) {
235 snprintf(numserv, sizeof(numserv), "%d", ntohs(port));
236 if ((strlen(numserv) + 1) > servlen)
237 ERR(ENI_MEMORY);
238 strcpy(serv, numserv);
239 } else {
240 if ((strlen(sp->s_name) + 1) > servlen)
241 ERR(ENI_MEMORY);
242 strcpy(serv, sp->s_name);
243 }
244
245 #if 0
246 switch (sa->sa_family) {
247 case AF_INET:
248 v4a = ((struct sockaddr_in *)sa)->sin_addr.s_addr;
249 if (IN_MULTICAST(v4a) || IN_EXPERIMENTAL(v4a))
250 flags |= NI_NUMERICHOST;
251 v4a >>= IN_CLASSA_NSHIFT;
252 if (v4a == 0 || v4a == IN_LOOPBACKNET)
253 flags |= NI_NUMERICHOST;
254 break;
255
256 case AF_INET6:
257 pfx = ((struct sockaddr_in6 *)sa)->sin6_addr.s6_addr[0];
258 if (pfx == 0 || pfx == 0xfe || pfx == 0xff)
259 flags |= NI_NUMERICHOST;
260 break;
261 }
262 #endif
263
264 if (host == NULL || hostlen == 0U) {
265 /*
266 * What should we do?
267 */
268 } else if (flags & NI_NUMERICHOST) {
269 if (lwres_net_ntop(afd->a_af, addr, numaddr, sizeof(numaddr))
270 == NULL)
271 ERR(ENI_SYSTEM);
272 #if defined(LWRES_HAVE_SIN6_SCOPE_ID)
273 if (afd->a_af == AF_INET6 &&
274 ((const struct sockaddr_in6 *)sa)->sin6_scope_id) {
275 char *p = numaddr + strlen(numaddr);
276 const char *stringscope = NULL;
277 #if 0
278 if ((flags & NI_NUMERICSCOPE) == 0) {
279 /*
280 * Vendors may want to add support for
281 * non-numeric scope identifier.
282 */
283 stringscope = foo;
284 }
285 #endif
286 if (stringscope == NULL) {
287 snprintf(p, sizeof(numaddr) - (p - numaddr),
288 "%%%u",
289 ((const struct sockaddr_in6 *)sa)->sin6_scope_id);
290 } else {
291 snprintf(p, sizeof(numaddr) - (p - numaddr),
292 "%%%s", stringscope);
293 }
294 }
295 #endif
296 if (strlen(numaddr) + 1 > hostlen)
297 ERR(ENI_MEMORY);
298 strcpy(host, numaddr);
299 } else {
300 switch (family) {
301 case AF_INET:
302 lwf = LWRES_ADDRTYPE_V4;
303 break;
304 case AF_INET6:
305 lwf = LWRES_ADDRTYPE_V6;
306 break;
307 default:
308 INSIST(0);
309 }
310
311 n = lwres_context_create(&lwrctx, NULL, NULL, NULL, 0);
312 if (n == 0)
313 (void) lwres_conf_parse(lwrctx, lwres_resolv_conf);
314
315 if (n == 0)
316 n = lwres_getnamebyaddr(lwrctx, lwf,
317 (lwres_uint16_t)afd->a_addrlen,
318 addr, &by);
319 if (n == 0) {
320 if (flags & NI_NOFQDN) {
321 p = strchr(by->realname, '.');
322 if (p)
323 *p = '\0';
324 }
325 if ((strlen(by->realname) + 1) > hostlen)
326 ERR(ENI_MEMORY);
327 strcpy(host, by->realname);
328 } else {
329 if (flags & NI_NAMEREQD)
330 ERR(ENI_NOHOSTNAME);
331 if (lwres_net_ntop(afd->a_af, addr, numaddr,
332 sizeof(numaddr))
333 == NULL)
334 ERR(ENI_NOHOSTNAME);
335 if ((strlen(numaddr) + 1) > hostlen)
336 ERR(ENI_MEMORY);
337 strcpy(host, numaddr);
338 }
339 }
340 result = SUCCESS;
341 cleanup:
342 if (by != NULL)
343 lwres_gnbaresponse_free(lwrctx, &by);
344 if (lwrctx != NULL) {
345 lwres_conf_clear(lwrctx);
346 lwres_context_destroy(&lwrctx);
347 }
348 return (result);
349 }
350