xref: /dragonfly/lib/libc/net/getnameinfo.c (revision b40e316c) 
1 /*	$FreeBSD: src/lib/libc/net/getnameinfo.c,v 1.4.2.5 2002/07/31 10:11:09 ume Exp $	*/
2 /*	$DragonFly: src/lib/libc/net/getnameinfo.c,v 1.3 2003/11/12 20:21:24 eirikn Exp $	*/
3 /*	$KAME: getnameinfo.c,v 1.61 2002/06/27 09:25:47 itojun Exp $	*/
4 
5 /*
6  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
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 <netinet/in.h>
52 #include <arpa/inet.h>
53 #include <arpa/nameser.h>
54 #include <netdb.h>
55 #include <resolv.h>
56 #include <string.h>
57 #include <stddef.h>
58 #include <errno.h>
59 
60 static const struct afd {
61 	int a_af;
62 	int a_addrlen;
63 	int a_socklen;
64 	int a_off;
65 } afdl [] = {
66 #ifdef INET6
67 	{PF_INET6, sizeof(struct in6_addr), sizeof(struct sockaddr_in6),
68 		offsetof(struct sockaddr_in6, sin6_addr)},
69 #endif
70 	{PF_INET, sizeof(struct in_addr), sizeof(struct sockaddr_in),
71 		offsetof(struct sockaddr_in, sin_addr)},
72 	{0, 0, 0},
73 };
74 
75 struct sockinet {
76 	u_char	si_len;
77 	u_char	si_family;
78 	u_short	si_port;
79 };
80 
81 #ifdef INET6
82 static int ip6_parsenumeric (const struct sockaddr *, const char *, char *,
83     size_t, int);
84 static int ip6_sa2str (const struct sockaddr_in6 *, char *, size_t, int);
85 #endif
86 
87 int
88 getnameinfo(sa, salen, host, hostlen, serv, servlen, flags)
89 	const struct sockaddr *sa;
90 	socklen_t salen;
91 	char *host;
92 	size_t hostlen;
93 	char *serv;
94 	size_t servlen;
95 	int flags;
96 {
97 	const struct afd *afd;
98 	struct servent *sp;
99 	struct hostent *hp;
100 	u_short port;
101 	int family, i;
102 	const char *addr;
103 	u_int32_t v4a;
104 	int h_error;
105 	char numserv[512];
106 	char numaddr[512];
107 
108 	if (sa == NULL)
109 		return EAI_FAIL;
110 
111 	if (sa->sa_len != salen)
112 		return EAI_FAIL;
113 
114 	family = sa->sa_family;
115 	for (i = 0; afdl[i].a_af; i++)
116 		if (afdl[i].a_af == family) {
117 			afd = &afdl[i];
118 			goto found;
119 		}
120 	return EAI_FAMILY;
121 
122  found:
123 	if (salen != afd->a_socklen)
124 		return EAI_FAIL;
125 
126 	/* network byte order */
127 	port = ((const struct sockinet *)sa)->si_port;
128 	addr = (const char *)sa + afd->a_off;
129 
130 	if (serv == NULL || servlen == 0) {
131 		/*
132 		 * do nothing in this case.
133 		 * in case you are wondering if "&&" is more correct than
134 		 * "||" here: rfc2553bis-03 says that serv == NULL OR
135 		 * servlen == 0 means that the caller does not want the result.
136 		 */
137 	} else {
138 		if (flags & NI_NUMERICSERV)
139 			sp = NULL;
140 		else {
141 			sp = getservbyport(port,
142 				(flags & NI_DGRAM) ? "udp" : "tcp");
143 		}
144 		if (sp) {
145 			if (strlen(sp->s_name) + 1 > servlen)
146 				return EAI_MEMORY;
147 			strlcpy(serv, sp->s_name, servlen);
148 		} else {
149 			snprintf(numserv, sizeof(numserv), "%u", ntohs(port));
150 			if (strlen(numserv) + 1 > servlen)
151 				return EAI_MEMORY;
152 			strlcpy(serv, numserv, servlen);
153 		}
154 	}
155 
156 	switch (sa->sa_family) {
157 	case AF_INET:
158 		v4a = (u_int32_t)
159 		    ntohl(((const struct sockaddr_in *)sa)->sin_addr.s_addr);
160 		if (IN_MULTICAST(v4a) || IN_EXPERIMENTAL(v4a))
161 			flags |= NI_NUMERICHOST;
162 		v4a >>= IN_CLASSA_NSHIFT;
163 		if (v4a == 0)
164 			flags |= NI_NUMERICHOST;
165 		break;
166 #ifdef INET6
167 	case AF_INET6:
168 	    {
169 		const struct sockaddr_in6 *sin6;
170 		sin6 = (const struct sockaddr_in6 *)sa;
171 		switch (sin6->sin6_addr.s6_addr[0]) {
172 		case 0x00:
173 			if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr))
174 				;
175 			else if (IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr))
176 				;
177 			else
178 				flags |= NI_NUMERICHOST;
179 			break;
180 		default:
181 			if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr)) {
182 				flags |= NI_NUMERICHOST;
183 			}
184 			else if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr))
185 				flags |= NI_NUMERICHOST;
186 			break;
187 		}
188 	    }
189 		break;
190 #endif
191 	}
192 	if (host == NULL || hostlen == 0) {
193 		/*
194 		 * do nothing in this case.
195 		 * in case you are wondering if "&&" is more correct than
196 		 * "||" here: rfc2553bis-03 says that host == NULL or
197 		 * hostlen == 0 means that the caller does not want the result.
198 		 */
199 	} else if (flags & NI_NUMERICHOST) {
200 		int numaddrlen;
201 
202 		/* NUMERICHOST and NAMEREQD conflicts with each other */
203 		if (flags & NI_NAMEREQD)
204 			return EAI_NONAME;
205 
206 		switch(afd->a_af) {
207 #ifdef INET6
208 		case AF_INET6:
209 		{
210 			int error;
211 
212 			if ((error = ip6_parsenumeric(sa, addr, host,
213 						      hostlen, flags)) != 0)
214 				return(error);
215 			break;
216 		}
217 #endif
218 		default:
219 			if (inet_ntop(afd->a_af, addr, numaddr, sizeof(numaddr))
220 			    == NULL)
221 				return EAI_SYSTEM;
222 			numaddrlen = strlen(numaddr);
223 			if (numaddrlen + 1 > hostlen) /* don't forget terminator */
224 				return EAI_MEMORY;
225 			strlcpy(host, numaddr, hostlen);
226 			break;
227 		}
228 	} else {
229 		hp = getipnodebyaddr(addr, afd->a_addrlen, afd->a_af, &h_error);
230 
231 		if (hp) {
232 #if 0
233 			/*
234 			 * commented out, since "for local host" is not
235 			 * implemented here - see RFC2553 p30
236 			 */
237 			if (flags & NI_NOFQDN) {
238 				char *p;
239 				p = strchr(hp->h_name, '.');
240 				if (p)
241 					*p = '\0';
242 			}
243 #endif
244 			if (strlen(hp->h_name) + 1 > hostlen) {
245 				freehostent(hp);
246 				return EAI_MEMORY;
247 			}
248 			strlcpy(host, hp->h_name, hostlen);
249 			freehostent(hp);
250 		} else {
251 			if (flags & NI_NAMEREQD)
252 				return EAI_NONAME;
253 			switch(afd->a_af) {
254 #ifdef INET6
255 			case AF_INET6:
256 			{
257 				int error;
258 
259 				if ((error = ip6_parsenumeric(sa, addr, host,
260 							      hostlen,
261 							      flags)) != 0)
262 					return(error);
263 				break;
264 			}
265 #endif
266 			default:
267 				if (inet_ntop(afd->a_af, addr, host,
268 				    hostlen) == NULL)
269 					return EAI_SYSTEM;
270 				break;
271 			}
272 		}
273 	}
274 	return(0);
275 }
276 
277 #ifdef INET6
278 static int
279 ip6_parsenumeric(sa, addr, host, hostlen, flags)
280 	const struct sockaddr *sa;
281 	const char *addr;
282 	char *host;
283 	size_t hostlen;
284 	int flags;
285 {
286 	int numaddrlen;
287 	char numaddr[512];
288 
289 	if (inet_ntop(AF_INET6, addr, numaddr, sizeof(numaddr)) == NULL)
290 		return EAI_SYSTEM;
291 
292 	numaddrlen = strlen(numaddr);
293 	if (numaddrlen + 1 > hostlen) /* don't forget terminator */
294 		return EAI_MEMORY;
295 	strlcpy(host, numaddr, hostlen);
296 
297 	if (((const struct sockaddr_in6 *)sa)->sin6_scope_id) {
298 		char zonebuf[MAXHOSTNAMELEN];
299 		int zonelen;
300 
301 		zonelen = ip6_sa2str(
302 		    (const struct sockaddr_in6 *)(const void *)sa,
303 		    zonebuf, sizeof(zonebuf), flags);
304 		if (zonelen < 0)
305 			return EAI_MEMORY;
306 		if (zonelen + 1 + numaddrlen + 1 > hostlen)
307 			return EAI_MEMORY;
308 
309 		/* construct <numeric-addr><delim><zoneid> */
310 		memcpy(host + numaddrlen + 1, zonebuf,
311 		    (size_t)zonelen);
312 		host[numaddrlen] = SCOPE_DELIMITER;
313 		host[numaddrlen + 1 + zonelen] = '\0';
314 	}
315 
316 	return 0;
317 }
318 
319 /* ARGSUSED */
320 static int
321 ip6_sa2str(sa6, buf, bufsiz, flags)
322 	const struct sockaddr_in6 *sa6;
323 	char *buf;
324 	size_t bufsiz;
325 	int flags;
326 {
327 	unsigned int ifindex;
328 	const struct in6_addr *a6;
329 	int n;
330 
331 	ifindex = (unsigned int)sa6->sin6_scope_id;
332 	a6 = &sa6->sin6_addr;
333 
334 #ifdef NI_NUMERICSCOPE
335 	if ((flags & NI_NUMERICSCOPE) != 0) {
336 		n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id);
337 		if (n < 0 || n >= bufsiz)
338 			return -1;
339 		else
340 			return n;
341 	}
342 #endif
343 
344 	/* if_indextoname() does not take buffer size.  not a good api... */
345 	if ((IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6) ||
346 	     IN6_IS_ADDR_MC_NODELOCAL(a6)) && bufsiz >= IF_NAMESIZE) {
347 		char *p = if_indextoname(ifindex, buf);
348 		if (p) {
349 			return(strlen(p));
350 		}
351 	}
352 
353 	/* last resort */
354 	n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id);
355 	if (n < 0 || n >= bufsiz)
356 		return -1;
357 	else
358 		return n;
359 }
360 #endif /* INET6 */
361