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