1 /*
2 * Portions Copyright (C) Internet Systems Consortium, Inc. ("ISC")
3 *
4 * This Source Code Form is subject to the terms of the Mozilla Public
5 * License, v. 2.0. If a copy of the MPL was not distributed with this
6 * file, you can obtain one at https://mozilla.org/MPL/2.0/.
7 *
8 * See the COPYRIGHT file distributed with this work for additional
9 * information regarding copyright ownership.
10 */
11
12 /*! \file */
13
14 /*
15 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
16 * All rights reserved.
17 *
18 * Redistribution and use in source and binary forms, with or without
19 * modification, are permitted provided that the following conditions
20 * are met:
21 * 1. Redistributions of source code must retain the above copyright
22 * notice, this list of conditions and the following disclaimer.
23 * 2. Redistributions in binary form must reproduce the above copyright
24 * notice, this list of conditions and the following disclaimer in the
25 * documentation and/or other materials provided with the distribution.
26 * 3. Neither the name of the project nor the names of its contributors
27 * may be used to endorse or promote products derived from this software
28 * without specific prior written permission.
29 *
30 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
31 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
32 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
33 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
34 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
35 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
36 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
37 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
38 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
39 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
40 * SUCH DAMAGE.
41 */
42
43 /*
44 * XXX
45 * Issues to be discussed:
46 * - Return values. There seems to be no standard for return value (RFC2553)
47 * but INRIA implementation returns EAI_xxx defined for getaddrinfo().
48 */
49
50
51 /**
52 * This function is equivalent to the getnameinfo(3) function defined in
53 * RFC2133. lwres_getnameinfo() returns the hostname for the struct
54 * sockaddr sa which is salen bytes long. The hostname is of length
55 * hostlen and is returned via *host. The maximum length of the hostname
56 * is 1025 bytes: #NI_MAXHOST.
57 *
58 * The name of the service associated with the port number in sa is
59 * returned in *serv. It is servlen bytes long. The maximum length of the
60 * service name is #NI_MAXSERV - 32 bytes.
61 *
62 * The flags argument sets the following bits:
63 *
64 * \li #NI_NOFQDN:
65 * A fully qualified domain name is not required for local hosts.
66 * The local part of the fully qualified domain name is returned
67 * instead.
68 *
69 * \li #NI_NUMERICHOST
70 * Return the address in numeric form, as if calling inet_ntop(),
71 * instead of a host name.
72 *
73 * \li #NI_NAMEREQD
74 * A name is required. If the hostname cannot be found in the DNS
75 * and this flag is set, a non-zero error code is returned. If the
76 * hostname is not found and the flag is not set, the address is
77 * returned in numeric form.
78 *
79 * \li #NI_NUMERICSERV
80 * The service name is returned as a digit string representing the
81 * port number.
82 *
83 * \li #NI_DGRAM
84 * Specifies that the service being looked up is a datagram
85 * service, and causes getservbyport() to be called with a second
86 * argument of "udp" instead of its default of "tcp". This is
87 * required for the few ports (512-514) that have different
88 * services for UDP and TCP.
89 *
90 * \section getnameinfo_return Return Values
91 *
92 * lwres_getnameinfo() returns 0 on success or a non-zero error code if
93 * an error occurs.
94 *
95 * \section getname_see See Also
96 *
97 * RFC2133, getservbyport(),
98 * lwres_getnamebyaddr(). lwres_net_ntop().
99 *
100 * \section getnameinfo_bugs Bugs
101 *
102 * RFC2133 fails to define what the nonzero return values of
103 * getnameinfo() are.
104 */
105
106 #include <config.h>
107
108 #include <inttypes.h>
109 #include <stdio.h>
110 #include <string.h>
111
112 #include <lwres/lwres.h>
113 #include <lwres/net.h>
114 #include <lwres/netdb.h>
115 #include "print_p.h"
116
117 #include "assert_p.h"
118 #include "unreachable_p.h"
119
120 #define SUCCESS 0
121
122 /*% afd structure definition */
123 static struct afd {
124 int a_af;
125 size_t a_addrlen;
126 size_t a_socklen;
127 } afdl [] = {
128 /*!
129 * First entry is linked last...
130 */
131 { AF_INET, sizeof(struct in_addr), sizeof(struct sockaddr_in) },
132 { AF_INET6, sizeof(struct in6_addr), sizeof(struct sockaddr_in6) },
133 {0, 0, 0},
134 };
135
136 #define ENI_NOSERVNAME 1
137 #define ENI_NOHOSTNAME 2
138 #define ENI_MEMORY 3
139 #define ENI_SYSTEM 4
140 #define ENI_FAMILY 5
141 #define ENI_SALEN 6
142 #define ENI_NOSOCKET 7
143
144 /*!
145 * The test against 0 is there to keep the Solaris compiler
146 * from complaining about "end-of-loop code not reached".
147 */
148 #define ERR(code) \
149 do { result = (code); \
150 if (result != 0) goto cleanup; \
151 } while (0)
152
153 /*% lightweight resolver socket address structure to hostname and service name */
154 int
lwres_getnameinfo(const struct sockaddr * sa,size_t salen,char * host,size_t hostlen,char * serv,size_t servlen,int flags)155 lwres_getnameinfo(const struct sockaddr *sa, size_t salen, char *host,
156 size_t hostlen, char *serv, size_t servlen, int flags)
157 {
158 struct afd *afd = NULL;
159 struct servent *sp;
160 unsigned short port;
161 #ifdef LWRES_PLATFORM_HAVESALEN
162 size_t len;
163 #endif
164 int family, i;
165 const void *addr;
166 #if 0
167 unsigned long v4a;
168 unsigned char pfx;
169 #endif
170 char numserv[sizeof("65000")];
171 char numaddr[sizeof("abcd:abcd:abcd:abcd:abcd:abcd:255.255.255.255")
172 + 1 + sizeof("4294967295")];
173 const char *proto;
174 uint32_t lwf = 0;
175 lwres_context_t *lwrctx = NULL;
176 lwres_gnbaresponse_t *by = NULL;
177 int result = SUCCESS;
178 int n;
179
180 if (sa == NULL)
181 ERR(ENI_NOSOCKET);
182
183 #ifdef LWRES_PLATFORM_HAVESALEN
184 len = sa->sa_len;
185 if (len != salen)
186 ERR(ENI_SALEN);
187 #endif
188
189 family = sa->sa_family;
190 for (i = 0; afdl[i].a_af; i++)
191 if (afdl[i].a_af == family) {
192 afd = &afdl[i];
193 goto found;
194 }
195 ERR(ENI_FAMILY);
196
197 found:
198 if (salen != afd->a_socklen)
199 ERR(ENI_SALEN);
200
201 switch (family) {
202 case AF_INET:
203 port = ((const struct sockaddr_in *)sa)->sin_port;
204 addr = &((const struct sockaddr_in *)sa)->sin_addr.s_addr;
205 break;
206
207 case AF_INET6:
208 port = ((const struct sockaddr_in6 *)sa)->sin6_port;
209 addr = ((const struct sockaddr_in6 *)sa)->sin6_addr.s6_addr;
210 break;
211
212 default:
213 port = 0;
214 addr = NULL;
215 POST(port); POST(addr);
216 INSIST(0);
217 }
218 proto = (flags & NI_DGRAM) ? "udp" : "tcp";
219
220 if (serv == NULL || servlen == 0U) {
221 /*
222 * Caller does not want service.
223 */
224 } else if ((flags & NI_NUMERICSERV) != 0 ||
225 (sp = getservbyport(port, proto)) == NULL) {
226 snprintf(numserv, sizeof(numserv), "%d", ntohs(port));
227 if ((strlen(numserv) + 1) > servlen)
228 ERR(ENI_MEMORY);
229 strcpy(serv, numserv);
230 } else {
231 if ((strlen(sp->s_name) + 1) > servlen)
232 ERR(ENI_MEMORY);
233 strcpy(serv, sp->s_name);
234 }
235
236 #if 0
237 switch (sa->sa_family) {
238 case AF_INET:
239 v4a = ((struct sockaddr_in *)sa)->sin_addr.s_addr;
240 if (IN_MULTICAST(v4a) || IN_EXPERIMENTAL(v4a))
241 flags |= NI_NUMERICHOST;
242 v4a >>= IN_CLASSA_NSHIFT;
243 if (v4a == 0 || v4a == IN_LOOPBACKNET)
244 flags |= NI_NUMERICHOST;
245 break;
246
247 case AF_INET6:
248 pfx = ((struct sockaddr_in6 *)sa)->sin6_addr.s6_addr[0];
249 if (pfx == 0 || pfx == 0xfe || pfx == 0xff)
250 flags |= NI_NUMERICHOST;
251 break;
252 }
253 #endif
254
255 if (host == NULL || hostlen == 0U) {
256 /*
257 * What should we do?
258 */
259 } else if (flags & NI_NUMERICHOST) {
260 if (lwres_net_ntop(afd->a_af, addr, numaddr, sizeof(numaddr))
261 == NULL)
262 ERR(ENI_SYSTEM);
263 #if defined(LWRES_HAVE_SIN6_SCOPE_ID)
264 if (afd->a_af == AF_INET6 &&
265 ((const struct sockaddr_in6 *)sa)->sin6_scope_id) {
266 char *p = numaddr + strlen(numaddr);
267 const char *stringscope = NULL;
268 #if 0
269 if ((flags & NI_NUMERICSCOPE) == 0) {
270 /*
271 * Vendors may want to add support for
272 * non-numeric scope identifier.
273 */
274 stringscope = foo;
275 }
276 #endif
277 if (stringscope == NULL) {
278 snprintf(p, sizeof(numaddr) - (p - numaddr),
279 "%%%u",
280 ((const struct sockaddr_in6 *)sa)->sin6_scope_id);
281 } else {
282 snprintf(p, sizeof(numaddr) - (p - numaddr),
283 "%%%s", stringscope);
284 }
285 }
286 #endif
287 if (strlen(numaddr) + 1 > hostlen)
288 ERR(ENI_MEMORY);
289 strcpy(host, numaddr);
290 } else {
291 switch (family) {
292 case AF_INET:
293 lwf = LWRES_ADDRTYPE_V4;
294 break;
295 case AF_INET6:
296 lwf = LWRES_ADDRTYPE_V6;
297 break;
298 default:
299 INSIST(0);
300 ISC_UNREACHABLE();
301 }
302
303 n = lwres_context_create(&lwrctx, NULL, NULL, NULL, 0);
304 if (n == 0) {
305 (void) lwres_conf_parse(lwrctx, lwres_resolv_conf);
306
307 n = lwres_getnamebyaddr(lwrctx, lwf,
308 (uint16_t)afd->a_addrlen,
309 addr, &by);
310 }
311 if (n == 0) {
312 if (flags & NI_NOFQDN) {
313 char *p = strchr(by->realname, '.');
314 if (p)
315 *p = '\0';
316 }
317 if ((strlen(by->realname) + 1) > hostlen)
318 ERR(ENI_MEMORY);
319 strcpy(host, by->realname);
320 } else {
321 if (flags & NI_NAMEREQD)
322 ERR(ENI_NOHOSTNAME);
323 if (lwres_net_ntop(afd->a_af, addr, numaddr,
324 sizeof(numaddr))
325 == NULL)
326 ERR(ENI_NOHOSTNAME);
327 if ((strlen(numaddr) + 1) > hostlen)
328 ERR(ENI_MEMORY);
329 strcpy(host, numaddr);
330 }
331 }
332 result = SUCCESS;
333 cleanup:
334 if (by != NULL)
335 lwres_gnbaresponse_free(lwrctx, &by);
336 if (lwrctx != NULL) {
337 lwres_conf_clear(lwrctx);
338 lwres_context_destroy(&lwrctx);
339 }
340 return (result);
341 }
342