1/*	$KAME: getnameinfo.c,v 1.61 2002/06/27 09:25:47 itojun Exp $	*/
2
3/*
4 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
5 * Copyright (c) 2000 Ben Harris.
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the project nor the names of its contributors
17 *    may be used to endorse or promote products derived from this software
18 *    without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33/*
34 * Issues to be discussed:
35 * - Thread safe-ness must be checked
36 * - RFC2553 says that we should raise error on short buffer.  X/Open says
37 *   we need to truncate the result.  We obey RFC2553 (and X/Open should be
38 *   modified).  ipngwg rough consensus seems to follow RFC2553.
39 * - What is "local" in NI_FQDN?
40 * - NI_NAMEREQD and NI_NUMERICHOST conflict with each other.
41 * - (KAME extension) always attach textual scopeid (fe80::1%lo0), if
42 *   sin6_scope_id is filled - standardization status?
43 *   XXX breaks backward compat for code that expects no scopeid.
44 *   beware on merge.
45 */
46
47#include <sys/cdefs.h>
48__FBSDID("$FreeBSD: releng/10.3/lib/libc/net/getnameinfo.c 287736 2015-09-13 03:15:37Z hrs $");
49
50#include <sys/types.h>
51#include <sys/socket.h>
52#include <net/if.h>
53#include <net/if_dl.h>
54#include <net/if_types.h>
55#include <net/firewire.h>
56#include <netinet/in.h>
57#include <arpa/inet.h>
58#include <arpa/nameser.h>
59#include <netdb.h>
60#include <resolv.h>
61#include <string.h>
62#include <stddef.h>
63#include <errno.h>
64
65static int	getnameinfo_inet(const struct sockaddr *, socklen_t, char *,
66    size_t, char *, size_t, int);
67#ifdef INET6
68static int ip6_parsenumeric(const struct sockaddr *, const char *, char *,
69    size_t, int);
70static int ip6_sa2str(const struct sockaddr_in6 *, char *, size_t, int);
71#endif
72static int	getnameinfo_link(const struct sockaddr *, socklen_t, char *,
73    size_t, char *, size_t, int);
74static int	hexname(const u_int8_t *, size_t, char *, size_t);
75
76int
77getnameinfo(const struct sockaddr *sa, socklen_t salen,
78    char *host, size_t hostlen, char *serv, size_t servlen,
79    int flags)
80{
81	if (sa == NULL)
82		return (EAI_FAIL);
83
84	switch (sa->sa_family) {
85	case AF_INET:
86#ifdef INET6
87	case AF_INET6:
88#endif
89		return getnameinfo_inet(sa, salen, host, hostlen, serv,
90		    servlen, flags);
91	case AF_LINK:
92		return getnameinfo_link(sa, salen, host, hostlen, serv,
93		    servlen, flags);
94	default:
95		return EAI_FAMILY;
96	}
97}
98
99static const struct afd {
100	int a_af;
101	size_t a_addrlen;
102	socklen_t a_socklen;
103	int a_off;
104} afdl [] = {
105#ifdef INET6
106	{PF_INET6, sizeof(struct in6_addr), sizeof(struct sockaddr_in6),
107		offsetof(struct sockaddr_in6, sin6_addr)},
108#endif
109	{PF_INET, sizeof(struct in_addr), sizeof(struct sockaddr_in),
110		offsetof(struct sockaddr_in, sin_addr)},
111	{0, 0, 0},
112};
113
114struct sockinet {
115	u_char	si_len;
116	u_char	si_family;
117	u_short	si_port;
118};
119
120static int
121getnameinfo_inet(const struct sockaddr *sa, socklen_t salen,
122    char *host, size_t hostlen, char *serv, size_t servlen,
123    int flags)
124{
125	const struct afd *afd;
126	struct servent *sp;
127	struct hostent *hp;
128	u_short port;
129	const char *addr;
130	u_int32_t v4a;
131	int h_error;
132	char numserv[512];
133	char numaddr[512];
134
135	for (afd = &afdl[0]; afd->a_af > 0; afd++) {
136		if (afd->a_af == sa->sa_family)
137			break;
138	}
139	if (afd->a_af == 0)
140		return (EAI_FAMILY);
141
142	if (salen != afd->a_socklen)
143		return EAI_FAIL;
144
145	/* network byte order */
146	port = ((const struct sockinet *)sa)->si_port;
147	addr = (const char *)sa + afd->a_off;
148
149	if (serv == NULL || servlen == 0) {
150		/*
151		 * do nothing in this case.
152		 * in case you are wondering if "&&" is more correct than
153		 * "||" here: rfc2553bis-03 says that serv == NULL OR
154		 * servlen == 0 means that the caller does not want the result.
155		 */
156	} else {
157		if (flags & NI_NUMERICSERV)
158			sp = NULL;
159		else {
160			sp = getservbyport(port,
161				(flags & NI_DGRAM) ? "udp" : "tcp");
162		}
163		if (sp) {
164			if (strlen(sp->s_name) + 1 > servlen)
165				return EAI_MEMORY;
166			strlcpy(serv, sp->s_name, servlen);
167		} else {
168			snprintf(numserv, sizeof(numserv), "%u", ntohs(port));
169			if (strlen(numserv) + 1 > servlen)
170				return EAI_MEMORY;
171			strlcpy(serv, numserv, servlen);
172		}
173	}
174
175	switch (sa->sa_family) {
176	case AF_INET:
177		v4a = (u_int32_t)
178		    ntohl(((const struct sockaddr_in *)sa)->sin_addr.s_addr);
179		if (IN_MULTICAST(v4a) || IN_EXPERIMENTAL(v4a))
180			flags |= NI_NUMERICHOST;
181		v4a >>= IN_CLASSA_NSHIFT;
182		if (v4a == 0)
183			flags |= NI_NUMERICHOST;
184		break;
185#ifdef INET6
186	case AF_INET6:
187	    {
188		const struct sockaddr_in6 *sin6;
189		sin6 = (const struct sockaddr_in6 *)sa;
190		switch (sin6->sin6_addr.s6_addr[0]) {
191		case 0x00:
192			if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr))
193				;
194			else if (IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr))
195				;
196			else
197				flags |= NI_NUMERICHOST;
198			break;
199		default:
200			if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr)) {
201				flags |= NI_NUMERICHOST;
202			}
203			else if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr))
204				flags |= NI_NUMERICHOST;
205			break;
206		}
207	    }
208		break;
209#endif
210	}
211	if (host == NULL || hostlen == 0) {
212		/*
213		 * do nothing in this case.
214		 * in case you are wondering if "&&" is more correct than
215		 * "||" here: rfc2553bis-03 says that host == NULL or
216		 * hostlen == 0 means that the caller does not want the result.
217		 */
218	} else if (flags & NI_NUMERICHOST) {
219		size_t numaddrlen;
220
221		/* NUMERICHOST and NAMEREQD conflicts with each other */
222		if (flags & NI_NAMEREQD)
223			return EAI_NONAME;
224
225		switch(afd->a_af) {
226#ifdef INET6
227		case AF_INET6:
228		{
229			int error;
230
231			if ((error = ip6_parsenumeric(sa, addr, host,
232						      hostlen, flags)) != 0)
233				return(error);
234			break;
235		}
236#endif
237		default:
238			if (inet_ntop(afd->a_af, addr, numaddr, sizeof(numaddr))
239			    == NULL)
240				return EAI_SYSTEM;
241			numaddrlen = strlen(numaddr);
242			if (numaddrlen + 1 > hostlen) /* don't forget terminator */
243				return EAI_MEMORY;
244			strlcpy(host, numaddr, hostlen);
245			break;
246		}
247	} else {
248		hp = getipnodebyaddr(addr, afd->a_addrlen, afd->a_af, &h_error);
249
250		if (hp) {
251#if 0
252			/*
253			 * commented out, since "for local host" is not
254			 * implemented here - see RFC2553 p30
255			 */
256			if (flags & NI_NOFQDN) {
257				char *p;
258				p = strchr(hp->h_name, '.');
259				if (p)
260					*p = '\0';
261			}
262#endif
263			if (strlen(hp->h_name) + 1 > hostlen) {
264				freehostent(hp);
265				return EAI_MEMORY;
266			}
267			strlcpy(host, hp->h_name, hostlen);
268			freehostent(hp);
269		} else {
270			if (flags & NI_NAMEREQD)
271				return EAI_NONAME;
272			switch(afd->a_af) {
273#ifdef INET6
274			case AF_INET6:
275			{
276				int error;
277
278				if ((error = ip6_parsenumeric(sa, addr, host,
279							      hostlen,
280							      flags)) != 0)
281					return(error);
282				break;
283			}
284#endif
285			default:
286				if (inet_ntop(afd->a_af, addr, host,
287				    hostlen) == NULL)
288					return EAI_SYSTEM;
289				break;
290			}
291		}
292	}
293	return(0);
294}
295
296#ifdef INET6
297static int
298ip6_parsenumeric(const struct sockaddr *sa, const char *addr,
299    char *host, size_t hostlen, int flags)
300{
301	size_t numaddrlen;
302	char numaddr[512];
303
304	if (inet_ntop(AF_INET6, addr, numaddr, sizeof(numaddr)) == NULL)
305		return EAI_SYSTEM;
306
307	numaddrlen = strlen(numaddr);
308	if (numaddrlen + 1 > hostlen) /* don't forget terminator */
309		return EAI_OVERFLOW;
310	strlcpy(host, numaddr, hostlen);
311
312	if (((const struct sockaddr_in6 *)sa)->sin6_scope_id) {
313		char zonebuf[MAXHOSTNAMELEN];
314		int zonelen;
315
316		zonelen = ip6_sa2str(
317		    (const struct sockaddr_in6 *)(const void *)sa,
318		    zonebuf, sizeof(zonebuf), flags);
319		if (zonelen < 0)
320			return EAI_OVERFLOW;
321		if (zonelen + 1 + numaddrlen + 1 > hostlen)
322			return EAI_OVERFLOW;
323
324		/* construct <numeric-addr><delim><zoneid> */
325		memcpy(host + numaddrlen + 1, zonebuf,
326		    (size_t)zonelen);
327		host[numaddrlen] = SCOPE_DELIMITER;
328		host[numaddrlen + 1 + zonelen] = '\0';
329	}
330
331	return 0;
332}
333
334/* ARGSUSED */
335static int
336ip6_sa2str(const struct sockaddr_in6 *sa6, char *buf, size_t bufsiz, int flags)
337{
338	unsigned int ifindex;
339	const struct in6_addr *a6;
340	int n;
341
342	ifindex = (unsigned int)sa6->sin6_scope_id;
343	a6 = &sa6->sin6_addr;
344
345#ifdef NI_NUMERICSCOPE
346	if ((flags & NI_NUMERICSCOPE) != 0) {
347		n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id);
348		if (n < 0 || n >= bufsiz)
349			return -1;
350		else
351			return n;
352	}
353#endif
354
355	/* if_indextoname() does not take buffer size.  not a good api... */
356	if ((IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6) ||
357	     IN6_IS_ADDR_MC_NODELOCAL(a6)) && bufsiz >= IF_NAMESIZE) {
358		char *p = if_indextoname(ifindex, buf);
359		if (p) {
360			return(strlen(p));
361		}
362	}
363
364	/* last resort */
365	n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id);
366	if (n < 0 || (size_t)n >= bufsiz)
367		return -1;
368	else
369		return n;
370}
371#endif /* INET6 */
372
373/*
374 * getnameinfo_link():
375 * Format a link-layer address into a printable format, paying attention to
376 * the interface type.
377 */
378/* ARGSUSED */
379static int
380getnameinfo_link(const struct sockaddr *sa, socklen_t salen,
381    char *host, size_t hostlen, char *serv, size_t servlen, int flags)
382{
383	const struct sockaddr_dl *sdl =
384	    (const struct sockaddr_dl *)(const void *)sa;
385	const struct fw_hwaddr *iha;
386	int n;
387
388	if (serv != NULL && servlen > 0)
389		*serv = '\0';
390
391	if (sdl->sdl_nlen == 0 && sdl->sdl_alen == 0 && sdl->sdl_slen == 0) {
392		n = snprintf(host, hostlen, "link#%d", sdl->sdl_index);
393		if (n >= hostlen) {
394			*host = '\0';
395			return (EAI_MEMORY);
396		}
397		return (0);
398	}
399
400	if (sdl->sdl_nlen > 0 && sdl->sdl_alen == 0) {
401		n = sdl->sdl_nlen;
402		if (n >= hostlen) {
403			*host = '\0';
404			return (EAI_MEMORY);
405		}
406		memcpy(host, sdl->sdl_data, sdl->sdl_nlen);
407		host[n] = '\0';
408		return (0);
409	}
410
411	switch (sdl->sdl_type) {
412	case IFT_IEEE1394:
413		if (sdl->sdl_alen < sizeof(iha->sender_unique_ID_hi) +
414		    sizeof(iha->sender_unique_ID_lo))
415			return EAI_FAMILY;
416		iha = (const struct fw_hwaddr *)(const void *)LLADDR(sdl);
417		return hexname((const u_int8_t *)&iha->sender_unique_ID_hi,
418		    sizeof(iha->sender_unique_ID_hi) +
419		    sizeof(iha->sender_unique_ID_lo),
420		    host, hostlen);
421	/*
422	 * The following have zero-length addresses.
423	 * IFT_ATM	(net/if_atmsubr.c)
424	 * IFT_FAITH	(net/if_faith.c)
425	 * IFT_GIF	(net/if_gif.c)
426	 * IFT_LOOP	(net/if_loop.c)
427	 * IFT_PPP	(net/if_ppp.c, net/if_spppsubr.c)
428	 * IFT_SLIP	(net/if_sl.c, net/if_strip.c)
429	 * IFT_STF	(net/if_stf.c)
430	 * IFT_L2VLAN	(net/if_vlan.c)
431	 * IFT_BRIDGE (net/if_bridge.h>
432	 */
433	/*
434	 * The following use IPv4 addresses as link-layer addresses:
435	 * IFT_OTHER	(net/if_gre.c)
436	 * IFT_OTHER	(netinet/ip_ipip.c)
437	 */
438	/* default below is believed correct for all these. */
439	case IFT_ARCNET:
440	case IFT_ETHER:
441	case IFT_FDDI:
442	case IFT_HIPPI:
443	case IFT_ISO88025:
444	default:
445		return hexname((u_int8_t *)LLADDR(sdl), (size_t)sdl->sdl_alen,
446		    host, hostlen);
447	}
448}
449
450static int
451hexname(const u_int8_t *cp, size_t len, char *host, size_t hostlen)
452{
453	int i, n;
454	char *outp = host;
455
456	*outp = '\0';
457	for (i = 0; i < len; i++) {
458		n = snprintf(outp, hostlen, "%s%02x",
459		    i ? ":" : "", cp[i]);
460		if (n < 0 || n >= hostlen) {
461			*host = '\0';
462			return EAI_MEMORY;
463		}
464		outp += n;
465		hostlen -= n;
466	}
467	return 0;
468}
469