1 /*
2 * 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 * getnameinfo() returns the hostname for the struct sockaddr sa which is
45 * salen bytes long. The hostname is of length hostlen and is returned via
46 * *host. The maximum length of the hostname is 1025 bytes: #NI_MAXHOST.
47 *
48 * The name of the service associated with the port number in sa is
49 * returned in *serv. It is servlen bytes long. The maximum length of the
50 * service name is #NI_MAXSERV - 32 bytes.
51 *
52 * The flags argument sets the following bits:
53 *
54 * \li #NI_NOFQDN:
55 * A fully qualified domain name is not required for local hosts.
56 * The local part of the fully qualified domain name is returned
57 * instead.
58 *
59 * \li #NI_NUMERICHOST
60 * Return the address in numeric form, as if calling inet_ntop(),
61 * instead of a host name.
62 *
63 * \li #NI_NAMEREQD
64 * A name is required. If the hostname cannot be found in the DNS
65 * and this flag is set, a non-zero error code is returned. If the
66 * hostname is not found and the flag is not set, the address is
67 * returned in numeric form.
68 *
69 * \li #NI_NUMERICSERV
70 * The service name is returned as a digit string representing the
71 * port number.
72 *
73 * \li #NI_DGRAM
74 * Specifies that the service being looked up is a datagram
75 * service, and causes getservbyport() to be called with a second
76 * argument of "udp" instead of its default of "tcp". This is
77 * required for the few ports (512-514) that have different
78 * services for UDP and TCP.
79 *
80 * \section getnameinfo_return Return Values
81 *
82 * getnameinfo() returns 0 on success or a non-zero error code if
83 * an error occurs.
84 *
85 * \section getname_see See Also
86 *
87 * RFC3493, getservbyport(),
88 * getnamebyaddr(). inet_ntop().
89 */
90
91 #include <config.h>
92
93 #include <stdbool.h>
94 #include <stdio.h>
95 #include <string.h>
96
97 #include <isc/netaddr.h>
98 #include <isc/print.h>
99 #include <isc/sockaddr.h>
100 #include <isc/string.h>
101 #include <isc/util.h>
102
103 #include <dns/byaddr.h>
104 #include <dns/client.h>
105 #include <dns/fixedname.h>
106 #include <dns/name.h>
107 #include <dns/rdata.h>
108 #include <dns/rdataset.h>
109 #include <dns/rdatastruct.h>
110 #include <dns/result.h>
111
112 #include <irs/context.h>
113 #include <irs/netdb.h>
114
115 #define SUCCESS 0
116
117 /*% afd structure definition */
118 static struct afd {
119 int a_af;
120 size_t a_addrlen;
121 size_t a_socklen;
122 } afdl [] = {
123 /*!
124 * First entry is linked last...
125 */
126 { AF_INET, sizeof(struct in_addr), sizeof(struct sockaddr_in) },
127 { AF_INET6, sizeof(struct in6_addr), sizeof(struct sockaddr_in6) },
128 {0, 0, 0},
129 };
130
131 /*!
132 * The test against 0 is there to keep the Solaris compiler
133 * from complaining about "end-of-loop code not reached".
134 */
135 #define ERR(code) \
136 do { result = (code); \
137 if (result != 0) goto cleanup; \
138 } while (0)
139
140 int
getnameinfo(const struct sockaddr * sa,IRS_GETNAMEINFO_SOCKLEN_T salen,char * host,IRS_GETNAMEINFO_BUFLEN_T hostlen,char * serv,IRS_GETNAMEINFO_BUFLEN_T servlen,IRS_GETNAMEINFO_FLAGS_T flags)141 getnameinfo(const struct sockaddr *sa, IRS_GETNAMEINFO_SOCKLEN_T salen,
142 char *host, IRS_GETNAMEINFO_BUFLEN_T hostlen,
143 char *serv, IRS_GETNAMEINFO_BUFLEN_T servlen,
144 IRS_GETNAMEINFO_FLAGS_T flags)
145 {
146 struct afd *afd = NULL;
147 struct servent *sp;
148 unsigned short port = 0;
149 #ifdef IRS_PLATFORM_HAVESALEN
150 size_t len;
151 #endif
152 int family, i;
153 const void *addr = NULL;
154 char *p;
155 #if 0
156 unsigned long v4a;
157 unsigned char pfx;
158 #endif
159 char numserv[sizeof("65000")];
160 char numaddr[sizeof("abcd:abcd:abcd:abcd:abcd:abcd:255.255.255.255")
161 + 1 + sizeof("4294967295")];
162 const char *proto;
163 int result = SUCCESS;
164
165 if (sa == NULL)
166 ERR(EAI_FAIL);
167
168 #ifdef IRS_PLATFORM_HAVESALEN
169 len = sa->sa_len;
170 if (len != salen)
171 ERR(EAI_FAIL);
172 #endif
173
174 family = sa->sa_family;
175 for (i = 0; afdl[i].a_af; i++)
176 if (afdl[i].a_af == family) {
177 afd = &afdl[i];
178 goto found;
179 }
180 ERR(EAI_FAMILY);
181
182 found:
183 if (salen != afd->a_socklen)
184 ERR(EAI_FAIL);
185
186 switch (family) {
187 case AF_INET:
188 port = ((const struct sockaddr_in *)sa)->sin_port;
189 addr = &((const struct sockaddr_in *)sa)->sin_addr.s_addr;
190 break;
191
192 case AF_INET6:
193 port = ((const struct sockaddr_in6 *)sa)->sin6_port;
194 addr = ((const struct sockaddr_in6 *)sa)->sin6_addr.s6_addr;
195 break;
196
197 default:
198 INSIST(0);
199 ISC_UNREACHABLE();
200 }
201 proto = ((flags & NI_DGRAM) != 0) ? "udp" : "tcp";
202
203 if (serv == NULL || servlen == 0U) {
204 /*
205 * Caller does not want service.
206 */
207 } else if ((flags & NI_NUMERICSERV) != 0 ||
208 (sp = getservbyport(port, proto)) == NULL) {
209 snprintf(numserv, sizeof(numserv), "%d", ntohs(port));
210 if ((strlen(numserv) + 1) > servlen)
211 ERR(EAI_OVERFLOW);
212 strlcpy(serv, numserv, servlen);
213 } else {
214 if ((strlen(sp->s_name) + 1) > servlen)
215 ERR(EAI_OVERFLOW);
216 strlcpy(serv, sp->s_name, servlen);
217 }
218
219 #if 0
220 switch (sa->sa_family) {
221 case AF_INET:
222 v4a = ((struct sockaddr_in *)sa)->sin_addr.s_addr;
223 if (IN_MULTICAST(v4a) || IN_EXPERIMENTAL(v4a))
224 flags |= NI_NUMERICHOST;
225 v4a >>= IN_CLASSA_NSHIFT;
226 if (v4a == 0 || v4a == IN_LOOPBACKNET)
227 flags |= NI_NUMERICHOST;
228 break;
229
230 case AF_INET6:
231 pfx = ((struct sockaddr_in6 *)sa)->sin6_addr.s6_addr[0];
232 if (pfx == 0 || pfx == 0xfe || pfx == 0xff)
233 flags |= NI_NUMERICHOST;
234 break;
235 }
236 #endif
237
238 if (host == NULL || hostlen == 0U) {
239 /*
240 * do nothing in this case.
241 * in case you are wondering if "&&" is more correct than
242 * "||" here: RFC3493 says that host == NULL or hostlen == 0
243 * means that the caller does not want the result.
244 */
245 } else if ((flags & NI_NUMERICHOST) != 0) {
246 if (inet_ntop(afd->a_af, addr, numaddr, sizeof(numaddr))
247 == NULL)
248 ERR(EAI_SYSTEM);
249 #if defined(IRS_HAVE_SIN6_SCOPE_ID)
250 if (afd->a_af == AF_INET6 &&
251 ((const struct sockaddr_in6 *)sa)->sin6_scope_id) {
252 char *p = numaddr + strlen(numaddr);
253 const char *stringscope = NULL;
254 #ifdef VENDOR_SPECIFIC
255 /*
256 * Vendors may want to add support for
257 * non-numeric scope identifier.
258 */
259 stringscope = foo;
260 #endif
261 if (stringscope == NULL) {
262 snprintf(p, sizeof(numaddr) - (p - numaddr),
263 "%%%u",
264 ((const struct sockaddr_in6 *)sa)->sin6_scope_id);
265 } else {
266 snprintf(p, sizeof(numaddr) - (p - numaddr),
267 "%%%s", stringscope);
268 }
269 }
270 #endif
271 if (strlen(numaddr) + 1 > hostlen)
272 ERR(EAI_OVERFLOW);
273 strlcpy(host, numaddr, hostlen);
274 } else {
275 isc_netaddr_t netaddr;
276 dns_fixedname_t ptrfname;
277 dns_name_t *ptrname;
278 irs_context_t *irsctx = NULL;
279 dns_client_t *client;
280 bool found = false;
281 dns_namelist_t answerlist;
282 dns_rdataset_t *rdataset;
283 isc_region_t hostregion;
284 char hoststr[1024]; /* is this enough? */
285 isc_result_t iresult;
286
287 /* Get IRS context and the associated DNS client object */
288 iresult = irs_context_get(&irsctx);
289 if (iresult != ISC_R_SUCCESS)
290 ERR(EAI_FAIL);
291 client = irs_context_getdnsclient(irsctx);
292
293 /* Make query name */
294 isc_netaddr_fromsockaddr(&netaddr, (const isc_sockaddr_t *)sa);
295 ptrname = dns_fixedname_initname(&ptrfname);
296 iresult = dns_byaddr_createptrname2(&netaddr, 0, ptrname);
297 if (iresult != ISC_R_SUCCESS)
298 ERR(EAI_FAIL);
299
300 /* Get the PTR RRset */
301 ISC_LIST_INIT(answerlist);
302 iresult = dns_client_resolve(client, ptrname,
303 dns_rdataclass_in,
304 dns_rdatatype_ptr,
305 DNS_CLIENTRESOPT_ALLOWRUN,
306 &answerlist);
307 switch (iresult) {
308 case ISC_R_SUCCESS:
309 /*
310 * a 'non-existent' error is not necessarily fatal for
311 * getnameinfo().
312 */
313 case DNS_R_NCACHENXDOMAIN:
314 case DNS_R_NCACHENXRRSET:
315 break;
316 case DNS_R_SIGINVALID:
317 case DNS_R_SIGEXPIRED:
318 case DNS_R_SIGFUTURE:
319 case DNS_R_KEYUNAUTHORIZED:
320 case DNS_R_MUSTBESECURE:
321 case DNS_R_COVERINGNSEC:
322 case DNS_R_NOTAUTHORITATIVE:
323 case DNS_R_NOVALIDKEY:
324 case DNS_R_NOVALIDDS:
325 case DNS_R_NOVALIDSIG:
326 /*
327 * Don't use ERR as GCC 7 wants to raise a
328 * warning with ERR about possible falling
329 * through which is impossible.
330 */
331 result = EAI_INSECUREDATA;
332 goto cleanup;
333 default:
334 ERR(EAI_FAIL);
335 }
336
337 /* Parse the answer for the hostname */
338 for (ptrname = ISC_LIST_HEAD(answerlist); ptrname != NULL;
339 ptrname = ISC_LIST_NEXT(ptrname, link)) {
340 for (rdataset = ISC_LIST_HEAD(ptrname->list);
341 rdataset != NULL;
342 rdataset = ISC_LIST_NEXT(rdataset, link)) {
343 if (!dns_rdataset_isassociated(rdataset))
344 continue;
345 if (rdataset->type != dns_rdatatype_ptr)
346 continue;
347
348 for (iresult = dns_rdataset_first(rdataset);
349 iresult == ISC_R_SUCCESS;
350 iresult = dns_rdataset_next(rdataset)) {
351 dns_rdata_t rdata;
352 dns_rdata_ptr_t rdata_ptr;
353 isc_buffer_t b;
354
355 dns_rdata_init(&rdata);
356 dns_rdataset_current(rdataset, &rdata);
357 dns_rdata_tostruct(&rdata, &rdata_ptr,
358 NULL);
359
360 isc_buffer_init(&b, hoststr,
361 sizeof(hoststr));
362 iresult =
363 dns_name_totext(&rdata_ptr.ptr,
364 true, &b);
365 dns_rdata_freestruct(&rdata_ptr);
366 if (iresult == ISC_R_SUCCESS) {
367 /*
368 * We ignore the rest of the
369 * answer. After all,
370 * getnameinfo() can return
371 * at most one hostname.
372 */
373 found = true;
374 isc_buffer_usedregion(
375 &b, &hostregion);
376 goto ptrfound;
377 }
378
379 }
380 }
381 }
382 ptrfound:
383 dns_client_freeresanswer(client, &answerlist);
384 if (found) {
385 if ((flags & NI_NOFQDN) != 0) {
386 p = strchr(hoststr, '.');
387 if (p)
388 *p = '\0';
389 }
390 if (hostregion.length + 1 > hostlen)
391 ERR(EAI_OVERFLOW);
392 snprintf(host, hostlen, "%.*s",
393 (int)hostregion.length,
394 (char *)hostregion.base);
395 } else {
396 if ((flags & NI_NAMEREQD) != 0)
397 ERR(EAI_NONAME);
398 if (inet_ntop(afd->a_af, addr, numaddr,
399 sizeof(numaddr)) == NULL)
400 ERR(EAI_SYSTEM);
401 if ((strlen(numaddr) + 1) > hostlen)
402 ERR(EAI_OVERFLOW);
403 strlcpy(host, numaddr, hostlen);
404 }
405 }
406 result = SUCCESS;
407
408 cleanup:
409 return (result);
410 }
411