1/*	$NetBSD: getnameinfo.c,v 1.53 2012/09/26 23:13:00 christos Exp $	*/
2/*	$KAME: getnameinfo.c,v 1.45 2000/09/25 22:43:56 itojun Exp $	*/
3
4/*
5 * Copyright (c) 2000 Ben Harris.
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/cdefs.h>
49#if defined(LIBC_SCCS) && !defined(lint)
50__RCSID("$NetBSD: getnameinfo.c,v 1.53 2012/09/26 23:13:00 christos Exp $");
51#endif /* LIBC_SCCS and not lint */
52
53#include <sys/types.h>
54#include <sys/socket.h>
55#include <sys/un.h>
56#include <net/if.h>
57#include <net/if_ieee1394.h>
58#include <net/if_types.h>
59#include <netinet/in.h>
60#include <arpa/inet.h>
61#include <assert.h>
62#include <limits.h>
63#include <netdb.h>
64#include <arpa/nameser.h>
65#include "resolv_netid.h"
66#include "resolv_private.h"
67#include <sys/system_properties.h>
68#include <stdlib.h>
69#include <unistd.h>
70#include <errno.h>
71#include <stddef.h>
72#include <string.h>
73
74static const struct afd {
75	int		a_af;
76	socklen_t	a_addrlen;
77	socklen_t	a_socklen;
78	int		a_off;
79} afdl [] = {
80#ifdef INET6
81	{PF_INET6, sizeof(struct in6_addr), sizeof(struct sockaddr_in6),
82		offsetof(struct sockaddr_in6, sin6_addr)},
83#endif
84	{PF_INET, sizeof(struct in_addr), sizeof(struct sockaddr_in),
85		offsetof(struct sockaddr_in, sin_addr)},
86	{0, 0, 0, 0},
87};
88
89struct sockinet {
90	u_char	si_len;
91	u_char	si_family;
92	u_short	si_port;
93};
94
95static int getnameinfo_inet(const struct sockaddr *, socklen_t, char *,
96    socklen_t, char *, socklen_t, int, unsigned, unsigned);
97#ifdef INET6
98static int ip6_parsenumeric(const struct sockaddr *, const char *, char *,
99				 socklen_t, int);
100static int ip6_sa2str(const struct sockaddr_in6 *, char *, size_t, int);
101#endif
102static int getnameinfo_local(const struct sockaddr *, socklen_t, char *,
103    socklen_t, char *, socklen_t, int);
104
105/*
106 * Top-level getnameinfo() code.  Look at the address family, and pick an
107 * appropriate function to call.
108 */
109int getnameinfo(const struct sockaddr* sa, socklen_t salen, char* host, size_t hostlen,
110		char* serv, size_t servlen, int flags)
111{
112	return android_getnameinfofornet(sa, salen, host, hostlen, serv, servlen, flags,
113			NETID_UNSET, MARK_UNSET);
114}
115
116int android_getnameinfofornet(const struct sockaddr* sa, socklen_t salen, char* host,
117		size_t hostlen, char* serv, size_t servlen, int flags, unsigned netid,
118		unsigned mark)
119{
120	switch (sa->sa_family) {
121	case AF_INET:
122	case AF_INET6:
123		return getnameinfo_inet(sa, salen, host, hostlen,
124				serv, servlen, flags, netid, mark);
125	case AF_LOCAL:
126		return getnameinfo_local(sa, salen, host, hostlen,
127		    serv, servlen, flags);
128	default:
129		return EAI_FAMILY;
130	}
131}
132
133/*
134 * getnameinfo_local():
135 * Format an local address into a printable format.
136 */
137/* ARGSUSED */
138static int
139getnameinfo_local(const struct sockaddr *sa, socklen_t salen,
140    char *host, socklen_t hostlen, char *serv, socklen_t servlen,
141    int flags __attribute__((unused)))
142{
143       const struct sockaddr_un *sun =
144           (const struct sockaddr_un *)(const void *)sa;
145
146       if (salen < (socklen_t) offsetof(struct sockaddr_un, sun_path)) {
147           return EAI_FAMILY;
148       }
149
150       if (serv != NULL && servlen > 0)
151               serv[0] = '\0';
152
153       if (host && hostlen > 0)
154               strlcpy(host, sun->sun_path,
155                   MIN((socklen_t) sizeof(sun->sun_path) + 1, hostlen));
156
157       return 0;
158}
159
160/*
161 * getnameinfo_inet():
162 * Format an IPv4 or IPv6 sockaddr into a printable string.
163 */
164static int
165getnameinfo_inet(const struct sockaddr* sa, socklen_t salen,
166       char *host, socklen_t hostlen,
167       char *serv, socklen_t servlen,
168       int flags, unsigned netid, unsigned mark)
169{
170	const struct afd *afd;
171	struct servent *sp;
172	struct hostent *hp;
173	u_short port;
174	int family, i;
175	const char *addr;
176	uint32_t v4a;
177	char numserv[512];
178	char numaddr[512];
179
180	/* sa is checked below */
181	/* host may be NULL */
182	/* serv may be NULL */
183
184	if (sa == NULL)
185		return EAI_FAIL;
186
187	family = sa->sa_family;
188	for (i = 0; afdl[i].a_af; i++)
189		if (afdl[i].a_af == family) {
190			afd = &afdl[i];
191			goto found;
192		}
193	return EAI_FAMILY;
194
195 found:
196	// http://b/1889275: callers should be allowed to provide too much
197	// space, but not too little.
198	if (salen < afd->a_socklen) {
199		return EAI_FAMILY;
200	}
201
202	/* network byte order */
203	port = ((const struct sockinet *)(const void *)sa)->si_port;
204	addr = (const char *)(const void *)sa + afd->a_off;
205
206	if (serv == NULL || servlen == 0) {
207		/*
208		 * do nothing in this case.
209		 * in case you are wondering if "&&" is more correct than
210		 * "||" here: rfc2553bis-03 says that serv == NULL OR
211		 * servlen == 0 means that the caller does not want the result.
212		 */
213	} else {
214		if (flags & NI_NUMERICSERV)
215			sp = NULL;
216		else {
217			sp = getservbyport(port,
218				(flags & NI_DGRAM) ? "udp" : "tcp");
219		}
220		if (sp) {
221			if (strlen(sp->s_name) + 1 > (size_t)servlen)
222				return EAI_MEMORY;
223			strlcpy(serv, sp->s_name, servlen);
224		} else {
225			snprintf(numserv, sizeof(numserv), "%u", ntohs(port));
226			if (strlen(numserv) + 1 > (size_t)servlen)
227				return EAI_MEMORY;
228			strlcpy(serv, numserv, servlen);
229		}
230	}
231
232	switch (sa->sa_family) {
233	case AF_INET:
234		v4a = (uint32_t)
235		    ntohl(((const struct sockaddr_in *)
236		    (const void *)sa)->sin_addr.s_addr);
237		if (IN_MULTICAST(v4a) || IN_EXPERIMENTAL(v4a))
238			flags |= NI_NUMERICHOST;
239		v4a >>= IN_CLASSA_NSHIFT;
240		if (v4a == 0)
241			flags |= NI_NUMERICHOST;
242		break;
243#ifdef INET6
244	case AF_INET6:
245	    {
246		const struct sockaddr_in6 *sin6;
247		sin6 = (const struct sockaddr_in6 *)(const void *)sa;
248		switch (sin6->sin6_addr.s6_addr[0]) {
249		case 0x00:
250			if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr))
251				;
252			else if (IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr))
253				;
254			else
255				flags |= NI_NUMERICHOST;
256			break;
257		default:
258			if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr)) {
259				flags |= NI_NUMERICHOST;
260			}
261			else if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr))
262				flags |= NI_NUMERICHOST;
263			break;
264		}
265	    }
266		break;
267#endif
268	}
269	if (host == NULL || hostlen == 0) {
270		/*
271		 * do nothing in this case.
272		 * in case you are wondering if "&&" is more correct than
273		 * "||" here: rfc2553bis-03 says that host == NULL or
274		 * hostlen == 0 means that the caller does not want the result.
275		 */
276	} else if (flags & NI_NUMERICHOST) {
277		size_t numaddrlen;
278
279		/* NUMERICHOST and NAMEREQD conflicts with each other */
280		if (flags & NI_NAMEREQD)
281			return EAI_NONAME;
282
283		switch(afd->a_af) {
284#ifdef INET6
285		case AF_INET6:
286		{
287			int error;
288
289			if ((error = ip6_parsenumeric(sa, addr, host,
290						      hostlen, flags)) != 0)
291				return(error);
292			break;
293		}
294#endif
295		default:
296			if (inet_ntop(afd->a_af, addr, numaddr, sizeof(numaddr))
297			    == NULL)
298				return EAI_SYSTEM;
299			numaddrlen = strlen(numaddr);
300			if (numaddrlen + 1 > (size_t)hostlen) /* don't forget terminator */
301				return EAI_MEMORY;
302			strlcpy(host, numaddr, hostlen);
303			break;
304		}
305	} else {
306		hp = android_gethostbyaddrfornet_proxy(addr, afd->a_addrlen, afd->a_af, netid);
307		if (hp) {
308#if 0
309			/*
310			 * commented out, since "for local host" is not
311			 * implemented here - see RFC2553 p30
312			 */
313			if (flags & NI_NOFQDN) {
314				char *p;
315				p = strchr(hp->h_name, '.');
316				if (p)
317					TODO: Before uncommenting rewrite to avoid modifying hp.
318					*p = '\0';
319			}
320#endif
321			if (strlen(hp->h_name) + 1 > (size_t)hostlen) {
322				return EAI_MEMORY;
323			}
324			strlcpy(host, hp->h_name, hostlen);
325		} else {
326			if (flags & NI_NAMEREQD)
327				return EAI_NONAME;
328			switch(afd->a_af) {
329#ifdef INET6
330			case AF_INET6:
331			{
332				int error;
333
334				if ((error = ip6_parsenumeric(sa, addr, host,
335							      hostlen,
336							      flags)) != 0)
337					return(error);
338				break;
339			}
340#endif
341			default:
342				if (inet_ntop(afd->a_af, addr, host,
343				    hostlen) == NULL)
344					return EAI_SYSTEM;
345				break;
346			}
347		}
348	}
349	return(0);
350}
351
352#ifdef INET6
353static int
354ip6_parsenumeric(const struct sockaddr *sa, const char *addr, char *host,
355       socklen_t hostlen, int flags)
356{
357	size_t numaddrlen;
358	char numaddr[512];
359
360	assert(sa != NULL);
361	assert(addr != NULL);
362	assert(host != NULL);
363
364	if (inet_ntop(AF_INET6, addr, numaddr, sizeof(numaddr)) == NULL)
365		return EAI_SYSTEM;
366
367	numaddrlen = strlen(numaddr);
368	if (numaddrlen + 1 > (size_t)hostlen) /* don't forget terminator */
369		return EAI_OVERFLOW;
370	strlcpy(host, numaddr, hostlen);
371
372	if (((const struct sockaddr_in6 *)(const void *)sa)->sin6_scope_id) {
373		char zonebuf[MAXHOSTNAMELEN];
374		int zonelen;
375
376		zonelen = ip6_sa2str(
377		    (const struct sockaddr_in6 *)(const void *)sa,
378		    zonebuf, sizeof(zonebuf), flags);
379		if (zonelen < 0)
380			return EAI_OVERFLOW;
381		if ((size_t) zonelen + 1 + numaddrlen + 1 > (size_t)hostlen)
382			return EAI_OVERFLOW;
383		/* construct <numeric-addr><delim><zoneid> */
384		memcpy(host + numaddrlen + 1, zonebuf,
385		    (size_t)zonelen);
386		host[numaddrlen] = SCOPE_DELIMITER;
387		host[numaddrlen + 1 + zonelen] = '\0';
388	}
389
390	return 0;
391}
392
393/* ARGSUSED */
394static int
395ip6_sa2str(const struct sockaddr_in6 *sa6, char *buf, size_t bufsiz, int flags)
396{
397	unsigned int ifindex;
398	const struct in6_addr *a6;
399	int n;
400
401	assert(sa6 != NULL);
402	assert(buf != NULL);
403
404	ifindex = (unsigned int)sa6->sin6_scope_id;
405	a6 = &sa6->sin6_addr;
406
407#ifdef NI_NUMERICSCOPE
408	if ((flags & NI_NUMERICSCOPE) != 0) {
409		n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id);
410		if (n < 0 || n >= bufsiz)
411			return -1;
412		else
413			return n;
414	}
415#endif
416
417	/* if_indextoname() does not take buffer size.  not a good api... */
418	if ((IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6)) &&
419	    bufsiz >= IF_NAMESIZE) {
420		char *p = if_indextoname(ifindex, buf);
421		if (p) {
422			return(strlen(p));
423		}
424	}
425
426	/* last resort */
427	n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id);
428	if (n < 0 || (size_t) n >= bufsiz)
429		return -1;
430	else
431		return n;
432}
433#endif /* INET6 */
434