xref: /titanic_41/usr/src/lib/libresolv2/common/irs/getnameinfo.c (revision c5024742c2f7d10880eae26cc592353b20a58f4a)
1 /*
2  * Copyright 2003 Sun Microsystems, Inc.  All rights reserved.
3  * Use is subject to license terms.
4  */
5 
6 /*
7  * Issues to be discussed:
8  * - Thread safe-ness must be checked
9  */
10 
11 /*
12  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
13  * All rights reserved.
14  *
15  * Redistribution and use in source and binary forms, with or without
16  * modification, are permitted provided that the following conditions
17  * are met:
18  * 1. Redistributions of source code must retain the above copyright
19  *    notice, this list of conditions and the following disclaimer.
20  * 2. Redistributions in binary form must reproduce the above copyright
21  *    notice, this list of conditions and the following disclaimer in the
22  *    documentation and/or other materials provided with the distribution.
23  * 3. All advertising materials mentioning features or use of this software
24  *    must display the following acknowledgement:
25  *    This product includes software developed by WIDE Project and
26  *    its contributors.
27  * 4. Neither the name of the project nor the names of its contributors
28  *    may be used to endorse or promote products derived from this software
29  *    without specific prior written permission.
30  *
31  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
32  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
33  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
34  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
35  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
36  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
37  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
38  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
39  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
40  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
41  * SUCH DAMAGE.
42  */
43 
44 #pragma ident	"%Z%%M%	%I%	%E% SMI"
45 
46 #include <port_before.h>
47 
48 #include <sys/types.h>
49 #include <sys/socket.h>
50 
51 #include <netinet/in.h>
52 #include <arpa/nameser.h>
53 #include <arpa/inet.h>
54 #include <net/if.h>
55 
56 #include <netdb.h>
57 #include <resolv.h>
58 #include <string.h>
59 #include <stddef.h>
60 
61 #include <port_after.h>
62 
63 /*
64  * Note that a_off will be dynamically adjusted so that to be consistent
65  * with the definition of sockaddr_in{,6}.
66  * The value presented below is just a guess.
67  */
68 static struct afd {
69 	int a_af;
70 	int a_addrlen;
71 	size_t a_socklen;
72 	int a_off;
73 } afdl [] = {
74 	/* first entry is linked last... */
75 	{PF_INET, sizeof(struct in_addr), sizeof(struct sockaddr_in),
76 	 offsetof(struct sockaddr_in, sin_addr)},
77 	{PF_INET6, sizeof(struct in6_addr), sizeof(struct sockaddr_in6),
78 	 offsetof(struct sockaddr_in6, sin6_addr)},
79 	{0, 0, 0, 0},
80 };
81 
82 struct sockinet {
83 #ifdef HAVE_SA_LEN
84 	u_char	si_len;
85 #endif
86 	u_char	si_family;
87 	u_short	si_port;
88 };
89 
90 static int ip6_parsenumeric __P((const struct sockaddr *, const char *, char *,
91 				 size_t, int));
92 #ifdef HAVE_SIN6_SCOPE_ID
93 static int ip6_sa2str __P((const struct sockaddr_in6 *, char *, size_t, int));
94 #endif
95 
96 int
97 getnameinfo(sa, salen, host, hostlen, serv, servlen, flags)
98 	const struct sockaddr *sa;
99 #ifdef	ORIGINAL_ISC_CODE
100 	size_t salen;
101 #else
102 	socklen_t salen;
103 #endif
104 	char *host;
105 #ifdef	ORIGINAL_ISC_CODE
106 	size_t hostlen;
107 #else
108 	socklen_t hostlen;
109 #endif
110 	char *serv;
111 #ifdef	ORIGINAL_ISC_CODE
112 	size_t servlen;
113 #else
114 	socklen_t servlen;
115 #endif
116 	int flags;
117 {
118 	struct afd *afd;
119 	struct servent *sp;
120 	struct hostent *hp;
121 	u_short port;
122 #ifdef HAVE_SA_LEN
123 	size_t len;
124 #endif
125 	int family, i;
126 	const char *addr;
127 	char *p;
128 	char numserv[512];
129 	char numaddr[512];
130 	const struct sockaddr_in6 *sin6;
131 
132 	if (sa == NULL)
133 		return EAI_FAIL;
134 
135 #ifdef HAVE_SA_LEN
136 	len = sa->sa_len;
137 	if (len != salen) return EAI_FAIL;
138 #endif
139 
140 	family = sa->sa_family;
141 	for (i = 0; afdl[i].a_af; i++)
142 		if (afdl[i].a_af == family) {
143 			afd = &afdl[i];
144 			goto found;
145 		}
146 	return EAI_FAMILY;
147 
148  found:
149 	if (salen != afd->a_socklen) return EAI_FAIL;
150 
151 	port = ((const struct sockinet *)sa)->si_port; /* network byte order */
152 	addr = (const char *)sa + afd->a_off;
153 
154 	if (serv == NULL || servlen == 0) {
155 		/*
156 		 * rfc2553bis says that serv == NULL or servlen == 0 means that
157 		 * the caller does not want the result.
158 		 */
159 	} else if (flags & NI_NUMERICSERV) {
160 		sprintf(numserv, "%d", ntohs(port));
161 		if (strlen(numserv) > servlen)
162 			return EAI_MEMORY;
163 		strcpy(serv, numserv);
164 	} else {
165 		sp = getservbyport(port, (flags & NI_DGRAM) ? "udp" : "tcp");
166 		if (sp) {
167 			if (strlen(sp->s_name) + 1 > servlen)
168 				return EAI_MEMORY;
169 			strcpy(serv, sp->s_name);
170 		} else
171 			return EAI_NONAME;
172 	}
173 
174 	switch (sa->sa_family) {
175 	case AF_INET:
176 		if (ntohl(*(const u_long *)addr) >> IN_CLASSA_NSHIFT == 0)
177 			flags |= NI_NUMERICHOST;
178 		break;
179 	case AF_INET6:
180 		sin6 = (const struct sockaddr_in6 *)sa;
181 		switch (sin6->sin6_addr.s6_addr[0]) {
182 		case 0x00:
183 			if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr))
184 				;
185 			else if (IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr))
186 				;
187 			else
188 				flags |= NI_NUMERICHOST;
189 			break;
190 		default:
191 			if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr))
192 				flags |= NI_NUMERICHOST;
193 			else if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr))
194 				flags |= NI_NUMERICHOST;
195 			break;
196 		}
197 		break;
198 	}
199 	if (host == NULL || hostlen == 0) {
200 		/*
201 		 * rfc2553bis says that host == NULL or hostlen == 0 means that
202 		 * the caller does not want the result.
203 		 */
204 	} else if (flags & NI_NUMERICHOST) {
205 		goto numeric;
206 	} else {
207 		hp = gethostbyaddr(addr, afd->a_addrlen, afd->a_af);
208 
209 		if (hp) {
210 			if (flags & NI_NOFQDN) {
211 				p = strchr(hp->h_name, '.');
212 				if (p) *p = '\0';
213 			}
214 			if (strlen(hp->h_name) + 1 > hostlen)
215 				return EAI_MEMORY;
216 			strcpy(host, hp->h_name);
217 		} else {
218 			if (flags & NI_NAMEREQD)
219 				return EAI_NONAME;
220 		  numeric:
221 			switch(afd->a_af) {
222 			case AF_INET6:
223 			{
224 				int error;
225 
226 				if ((error = ip6_parsenumeric(sa, addr, host,
227 							      hostlen,
228 							      flags)) != 0)
229 					return(error);
230 				break;
231 			}
232 
233 			default:
234 				if (inet_ntop(afd->a_af, addr, numaddr,
235 					      sizeof(numaddr)) == NULL)
236 					return EAI_NONAME;
237 				if (strlen(numaddr) + 1 > hostlen)
238 					return EAI_MEMORY;
239 				strcpy(host, numaddr);
240 			}
241 		}
242 	}
243 	return(0);
244 }
245 
246 static int
247 ip6_parsenumeric(const struct sockaddr *sa, const char *addr, char *host,
248 		 size_t hostlen, int flags)
249 {
250 	size_t numaddrlen;
251 	char numaddr[512];
252 
253 #ifndef HAVE_SIN6_SCOPE_ID
254 	UNUSED(sa);
255 	UNUSED(flags);
256 #endif
257 
258 	if (inet_ntop(AF_INET6, addr, numaddr, sizeof(numaddr))
259 	    == NULL)
260 		return EAI_SYSTEM;
261 
262 	numaddrlen = strlen(numaddr);
263 	if (numaddrlen + 1 > hostlen) /* don't forget terminator */
264 		return EAI_MEMORY;
265 	strcpy(host, numaddr);
266 
267 #ifdef HAVE_SIN6_SCOPE_ID
268 	if (((const struct sockaddr_in6 *)sa)->sin6_scope_id) {
269 		char scopebuf[MAXHOSTNAMELEN]; /* XXX */
270 		int scopelen;
271 
272 		/* ip6_sa2str never fails */
273 		scopelen = ip6_sa2str((const struct sockaddr_in6 *)sa,
274 				      scopebuf, sizeof(scopebuf), flags);
275 
276 		if (scopelen + 1 + numaddrlen + 1 > hostlen)
277 			return EAI_MEMORY;
278 
279 		/* construct <numeric-addr><delim><scopeid> */
280 		memcpy(host + numaddrlen + 1, scopebuf,
281 		       scopelen);
282 		host[numaddrlen] = SCOPE_DELIMITER;
283 		host[numaddrlen + 1 + scopelen] = '\0';
284 	}
285 #endif
286 
287 	return 0;
288 }
289 
290 #ifdef HAVE_SIN6_SCOPE_ID
291 /* ARGSUSED */
292 static int
293 ip6_sa2str(const struct sockaddr_in6 *sa6, char *buf,
294 	   size_t bufsiz, int flags)
295 {
296 #ifdef USE_IFNAMELINKID
297 	unsigned int ifindex = (unsigned int)sa6->sin6_scope_id;
298 	const struct in6_addr *a6 = &sa6->sin6_addr;
299 #endif
300 	char tmp[64];
301 
302 #ifdef NI_NUMERICSCOPE
303 	if (flags & NI_NUMERICSCOPE) {
304 		sprintf(tmp, "%u", sa6->sin6_scope_id);
305 		if (bufsiz != 0) {
306 			strncpy(buf, tmp, bufsiz - 1);
307 			buf[bufsiz - 1] = '\0';
308 		}
309 		return(strlen(tmp));
310 	}
311 #endif
312 
313 #ifdef USE_IFNAMELINKID
314 	/*
315 	 * For a link-local address, convert the index to an interface
316 	 * name, assuming a one-to-one mapping between links and interfaces.
317 	 * Note, however, that this assumption is stronger than the
318 	 * specification of the scoped address architecture;  the
319 	 * specficication says that more than one interfaces can belong to
320 	 * a single link.
321 	 */
322 
323 	/* if_indextoname() does not take buffer size.  not a good api... */
324 	if ((IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6)) &&
325 	    bufsiz >= IF_NAMESIZE) {
326 		char *p = if_indextoname(ifindex, buf);
327 		if (p) {
328 			return(strlen(p));
329 		}
330 	}
331 #endif
332 
333 	/* last resort */
334 	sprintf(tmp, "%u", sa6->sin6_scope_id);
335 	if (bufsiz != 0) {
336 		strncpy(buf, tmp, bufsiz - 1);
337 		buf[bufsiz - 1] = '\0';
338 	}
339 	return(strlen(tmp));
340 }
341 #endif
342