xref: /freebsd/include/resolv.h (revision 58cf91d3b72a01777bacf72d66a648a744ae3143)
1 /*-
2  * SPDX-License-Identifier: (ISC AND BSD-3-Clause)
3  *
4  * Portions Copyright (C) 2004, 2005, 2008, 2009  Internet Systems Consortium, Inc. ("ISC")
5  * Portions Copyright (C) 1995-2003  Internet Software Consortium.
6  *
7  * Permission to use, copy, modify, and/or distribute this software for any
8  * purpose with or without fee is hereby granted, provided that the above
9  * copyright notice and this permission notice appear in all copies.
10  *
11  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
12  * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
13  * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
14  * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
15  * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
16  * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
17  * PERFORMANCE OF THIS SOFTWARE.
18  */
19 
20 /*
21  * Copyright (c) 1983, 1987, 1989
22  *    The Regents of the University of California.  All rights reserved.
23  *
24  * Redistribution and use in source and binary forms, with or without
25  * modification, are permitted provided that the following conditions
26  * are met:
27  * 1. Redistributions of source code must retain the above copyright
28  *    notice, this list of conditions and the following disclaimer.
29  * 2. Redistributions in binary form must reproduce the above copyright
30  *    notice, this list of conditions and the following disclaimer in the
31  *    documentation and/or other materials provided with the distribution.
32  * 3. Neither the name of the University nor the names of its contributors
33  *    may be used to endorse or promote products derived from this software
34  *    without specific prior written permission.
35  *
36  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
37  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
38  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
39  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
40  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
41  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
42  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
43  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
44  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
45  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
46  * SUCH DAMAGE.
47  */
48 
49 /*%
50  *	$Id: resolv.h,v 1.30 2009/03/03 01:52:48 each Exp $
51  */
52 
53 #ifndef _RESOLV_H_
54 #define	_RESOLV_H_
55 
56 #include <sys/param.h>
57 #include <sys/types.h>
58 #include <sys/cdefs.h>
59 #include <sys/socket.h>
60 #include <stdio.h>
61 #include <netinet/in.h>
62 #include <arpa/nameser.h>
63 
64 /*%
65  * Revision information.  This is the release date in YYYYMMDD format.
66  * It can change every day so the right thing to do with it is use it
67  * in preprocessor commands such as "#if (__RES > 19931104)".  Do not
68  * compare for equality; rather, use it to determine whether your resolver
69  * is new enough to contain a certain feature.
70  */
71 
72 #define	__RES	20090302
73 
74 /*%
75  * This used to be defined in res_query.c, now it's in herror.c.
76  * [XXX no it's not.  It's in irs/irs_data.c]
77  * It was
78  * never extern'd by any *.h file before it was placed here.  For thread
79  * aware programs, the last h_errno value set is stored in res->h_errno.
80  *
81  * XXX:	There doesn't seem to be a good reason for exposing RES_SET_H_ERRNO
82  *	(and __h_errno_set) to the public via <resolv.h>.
83  * XXX:	__h_errno_set is really part of IRS, not part of the resolver.
84  *	If somebody wants to build and use a resolver that doesn't use IRS,
85  *	what do they do?  Perhaps something like
86  *		#ifdef WANT_IRS
87  *		# define RES_SET_H_ERRNO(r,x) __h_errno_set(r,x)
88  *		#else
89  *		# define RES_SET_H_ERRNO(r,x) (h_errno = (r)->res_h_errno = (x))
90  *		#endif
91  */
92 
93 #define RES_SET_H_ERRNO(r,x) __h_errno_set(r,x)
94 struct __res_state; /*%< forward */
95 __BEGIN_DECLS
96 void __h_errno_set(struct __res_state *, int);
97 __END_DECLS
98 
99 /*%
100  * Resolver configuration file.
101  * Normally not present, but may contain the address of the
102  * initial name server(s) to query and the domain search list.
103  */
104 
105 #ifndef _PATH_RESCONF
106 #define	_PATH_RESCONF        "/etc/resolv.conf"
107 #endif
108 
109 typedef enum { res_goahead, res_nextns, res_modified, res_done, res_error }
110 	res_sendhookact;
111 
112 typedef res_sendhookact (*res_send_qhook)(struct sockaddr * const *,
113 					  const u_char **, int *,
114 					  u_char *, int, int *);
115 
116 typedef res_sendhookact (*res_send_rhook)(const struct sockaddr *,
117 					  const u_char *, int, u_char *,
118 					  int, int *);
119 
120 struct res_sym {
121 	int		number;	   /*%< Identifying number, like T_MX */
122 	const char *	name;	   /*%< Its symbolic name, like "MX" */
123 	const char *	humanname; /*%< Its fun name, like "mail exchanger" */
124 };
125 
126 /*%
127  * Global defines and variables for resolver stub.
128  */
129 #define	MAXNS			3	/*%< max # name servers we'll track */
130 #define	MAXDFLSRCH		3	/*%< # default domain levels to try */
131 #define	MAXDNSRCH		6	/*%< max # domains in search path */
132 #define	LOCALDOMAINPARTS	2	/*%< min levels in name that is "local" */
133 #define	RES_TIMEOUT		5	/*%< min. seconds between retries */
134 #define	MAXRESOLVSORT		10	/*%< number of net to sort on */
135 #define	RES_MAXNDOTS		15	/*%< should reflect bit field size */
136 #define	RES_MAXRETRANS		30	/*%< only for resolv.conf/RES_OPTIONS */
137 #define	RES_MAXRETRY		5	/*%< only for resolv.conf/RES_OPTIONS */
138 #define	RES_DFLRETRY		2	/*%< Default #/tries. */
139 #define	RES_MAXTIME		65535	/*%< Infinity, in milliseconds. */
140 struct __res_state_ext;
141 
142 struct __res_state {
143 	int	retrans;	 	/*%< retransmission time interval */
144 	int	retry;			/*%< number of times to retransmit */
145 	/*
146 	 * XXX: If `sun' is defined, `options' and `pfcode' are
147 	 * defined as u_int in original BIND9 distribution.  However,
148 	 * it breaks binary backward compatibility against FreeBSD's
149 	 * resolver.  So, we changed not to see `sun'.
150 	 */
151 #if defined(sun) && 0
152 	u_int	options;		/*%< option flags - see below. */
153 #else
154 	u_long	options;		/*%< option flags - see below. */
155 #endif
156 	int	nscount;		/*%< number of name servers */
157 	struct sockaddr_in
158 		nsaddr_list[MAXNS];	/*%< address of name server */
159 #define	nsaddr	nsaddr_list[0]		/*%< for backward compatibility */
160 	u_short	id;			/*%< current message id */
161 	char	*dnsrch[MAXDNSRCH+1];	/*%< components of domain to search */
162 	char	defdname[256];		/*%< default domain (deprecated) */
163 #if defined(sun) && 0
164 	u_int	pfcode;			/*%< RES_PRF_ flags - see below. */
165 #else
166 	u_long	pfcode;			/*%< RES_PRF_ flags - see below. */
167 #endif
168 	unsigned ndots:4;		/*%< threshold for initial abs. query */
169 	unsigned nsort:4;		/*%< number of elements in sort_list[] */
170 	char	unused[3];
171 	struct {
172 		struct in_addr	addr;
173 		u_int32_t	mask;
174 	} sort_list[MAXRESOLVSORT];
175 	res_send_qhook qhook;		/*%< query hook */
176 	res_send_rhook rhook;		/*%< response hook */
177 	int	res_h_errno;		/*%< last one set for this context */
178 	int	_vcsock;		/*%< PRIVATE: for res_send VC i/o */
179 	u_int	_flags;			/*%< PRIVATE: see below */
180 	u_int	_pad;			/*%< make _u 64 bit aligned */
181 	union {
182 		/* On an 32-bit arch this means 512b total. */
183 		char	pad[72 - 4*sizeof (int) - 3*sizeof (void *)];
184 		struct {
185 			u_int16_t		nscount;
186 			u_int16_t		nstimes[MAXNS];	/*%< ms. */
187 			int			nssocks[MAXNS];
188 			struct __res_state_ext *ext;	/*%< extension for IPv6 */
189 		} _ext;
190 	} _u;
191 	u_char	*_rnd;			/*%< PRIVATE: random state */
192 };
193 
194 typedef struct __res_state *res_state;
195 
196 union res_sockaddr_union {
197 	struct sockaddr_in	sin;
198 #ifdef IN6ADDR_ANY_INIT
199 	struct sockaddr_in6	sin6;
200 #endif
201 #ifdef ISC_ALIGN64
202 	int64_t			__align64;	/*%< 64bit alignment */
203 #else
204 	int32_t			__align32;	/*%< 32bit alignment */
205 #endif
206 	char			__space[128];   /*%< max size */
207 };
208 
209 /*%
210  * Resolver flags (used to be discrete per-module statics ints).
211  */
212 #define	RES_F_VC	0x00000001	/*%< socket is TCP */
213 #define	RES_F_CONN	0x00000002	/*%< socket is connected */
214 #define	RES_F_EDNS0ERR	0x00000004	/*%< EDNS0 caused errors */
215 #define	RES_F__UNUSED	0x00000008	/*%< (unused) */
216 #define	RES_F_LASTMASK	0x000000F0	/*%< ordinal server of last res_nsend */
217 #define	RES_F_LASTSHIFT	4		/*%< bit position of LASTMASK "flag" */
218 #define	RES_GETLAST(res) (((res)._flags & RES_F_LASTMASK) >> RES_F_LASTSHIFT)
219 
220 /* res_findzonecut2() options */
221 #define	RES_EXHAUSTIVE	0x00000001	/*%< always do all queries */
222 #define	RES_IPV4ONLY	0x00000002	/*%< IPv4 only */
223 #define	RES_IPV6ONLY	0x00000004	/*%< IPv6 only */
224 
225 /*%
226  * Resolver options (keep these in synch with res_debug.c, please)
227  */
228 #define RES_INIT	0x00000001	/*%< address initialized */
229 #define RES_DEBUG	0x00000002	/*%< print debug messages */
230 #define RES_AAONLY	0x00000004	/*%< authoritative answers only (!IMPL)*/
231 #define RES_USEVC	0x00000008	/*%< use virtual circuit */
232 #define RES_PRIMARY	0x00000010	/*%< query primary server only (!IMPL) */
233 #define RES_IGNTC	0x00000020	/*%< ignore truncation errors */
234 #define RES_RECURSE	0x00000040	/*%< recursion desired */
235 #define RES_DEFNAMES	0x00000080	/*%< use default domain name */
236 #define RES_STAYOPEN	0x00000100	/*%< Keep TCP socket open */
237 #define RES_DNSRCH	0x00000200	/*%< search up local domain tree */
238 #define	RES_INSECURE1	0x00000400	/*%< type 1 security disabled */
239 #define	RES_INSECURE2	0x00000800	/*%< type 2 security disabled */
240 #define	RES_NOALIASES	0x00001000	/*%< shuts off HOSTALIASES feature */
241 #define	RES_USE_INET6	0x00002000	/*%< use/map IPv6 in gethostbyname() */
242 #define RES_ROTATE	0x00004000	/*%< rotate ns list after each query */
243 #define	RES_NOCHECKNAME	0x00008000	/*%< do not check names for sanity. */
244 #define	RES_KEEPTSIG	0x00010000	/*%< do not strip TSIG records */
245 #define	RES_BLAST	0x00020000	/*%< blast all recursive servers */
246 #define RES_NSID	0x00040000      /*%< request name server ID */
247 #define RES_NOTLDQUERY	0x00100000	/*%< don't unqualified name as a tld */
248 #define RES_USE_DNSSEC	0x00200000	/*%< use DNSSEC using OK bit in OPT */
249 /* #define RES_DEBUG2	0x00400000 */	/* nslookup internal */
250 /* KAME extensions: use higher bit to avoid conflict with ISC use */
251 #define RES_USE_DNAME	0x10000000	/*%< use DNAME */
252 #define RES_USE_EDNS0	0x40000000	/*%< use EDNS0 if configured */
253 #define RES_NO_NIBBLE2	0x80000000	/*%< disable alternate nibble lookup */
254 
255 #define RES_DEFAULT	(RES_RECURSE | RES_DEFNAMES | \
256 			 RES_DNSRCH | RES_NO_NIBBLE2)
257 
258 /*%
259  * Resolver "pfcode" values.  Used by dig.
260  */
261 #define	RES_PRF_STATS	0x00000001
262 #define	RES_PRF_UPDATE	0x00000002
263 #define	RES_PRF_CLASS   0x00000004
264 #define	RES_PRF_CMD	0x00000008
265 #define	RES_PRF_QUES	0x00000010
266 #define	RES_PRF_ANS	0x00000020
267 #define	RES_PRF_AUTH	0x00000040
268 #define	RES_PRF_ADD	0x00000080
269 #define	RES_PRF_HEAD1	0x00000100
270 #define	RES_PRF_HEAD2	0x00000200
271 #define	RES_PRF_TTLID	0x00000400
272 #define	RES_PRF_HEADX	0x00000800
273 #define	RES_PRF_QUERY	0x00001000
274 #define	RES_PRF_REPLY	0x00002000
275 #define	RES_PRF_INIT	0x00004000
276 #define	RES_PRF_TRUNC	0x00008000
277 /*			0x00010000	*/
278 
279 /* Things involving an internal (static) resolver context. */
280 __BEGIN_DECLS
281 extern struct __res_state *__res_state(void);
282 __END_DECLS
283 #define _res (*__res_state())
284 
285 #ifndef __BIND_NOSTATIC
286 #define fp_nquery		__fp_nquery
287 #define fp_query		__fp_query
288 #define hostalias		__hostalias
289 #define p_query			__p_query
290 #define res_close		__res_close
291 #define res_init		__res_init
292 #define res_isourserver		__res_isourserver
293 #define res_mkquery		__res_mkquery
294 #define res_opt			__res_opt
295 #define res_query		__res_query
296 #define res_querydomain		__res_querydomain
297 #define res_search		__res_search
298 #define res_send		__res_send
299 #define res_sendsigned		__res_sendsigned
300 
301 __BEGIN_DECLS
302 void		fp_nquery(const u_char *, int, FILE *);
303 void		fp_query(const u_char *, FILE *);
304 const char *	hostalias(const char *);
305 void		p_query(const u_char *);
306 void		res_close(void);
307 int		res_init(void);
308 int		res_isourserver(const struct sockaddr_in *);
309 int		res_mkquery(int, const char *, int, int, const u_char *,
310 				 int, const u_char *, u_char *, int);
311 int		res_opt(int, u_char *, int, int);
312 int		res_query(const char *, int, int, u_char *, int);
313 int		res_querydomain(const char *, const char *, int, int,
314 				     u_char *, int);
315 int		res_search(const char *, int, int, u_char *, int);
316 int		res_send(const u_char *, int, u_char *, int);
317 int		res_sendsigned(const u_char *, int, ns_tsig_key *,
318 				    u_char *, int);
319 __END_DECLS
320 #endif
321 
322 #if !defined(SHARED_LIBBIND) || defined(LIB)
323 /*
324  * If libbind is a shared object (well, DLL anyway)
325  * these externs break the linker when resolv.h is
326  * included by a lib client (like named)
327  * Make them go away if a client is including this
328  *
329  */
330 extern const struct res_sym __p_key_syms[];
331 extern const struct res_sym __p_cert_syms[];
332 extern const struct res_sym __p_class_syms[];
333 extern const struct res_sym __p_type_syms[];
334 extern const struct res_sym __p_rcode_syms[];
335 #endif /* SHARED_LIBBIND */
336 
337 #define b64_ntop		__b64_ntop
338 #define b64_pton		__b64_pton
339 #define dn_comp			__dn_comp
340 #define dn_count_labels		__dn_count_labels
341 #define dn_expand		__dn_expand
342 #define dn_skipname		__dn_skipname
343 #define fp_resstat		__fp_resstat
344 #define loc_aton		__loc_aton
345 #define loc_ntoa		__loc_ntoa
346 #define p_cdname		__p_cdname
347 #define p_cdnname		__p_cdnname
348 #define p_class			__p_class
349 #define p_fqname		__p_fqname
350 #define p_fqnname		__p_fqnname
351 #define p_option		__p_option
352 #define p_secstodate		__p_secstodate
353 #define p_section		__p_section
354 #define p_time			__p_time
355 #define p_type			__p_type
356 #define p_rcode			__p_rcode
357 #define p_sockun		__p_sockun
358 #define putlong			__putlong
359 #define putshort		__putshort
360 #define res_dnok		__res_dnok
361 #if 0
362 #define res_findzonecut		__res_findzonecut
363 #endif
364 #define res_findzonecut2	__res_findzonecut2
365 #define res_hnok		__res_hnok
366 #define res_hostalias		__res_hostalias
367 #define res_mailok		__res_mailok
368 #define res_nameinquery		__res_nameinquery
369 #define res_nclose		__res_nclose
370 #define res_ninit		__res_ninit
371 #define res_nmkquery		__res_nmkquery
372 #define res_pquery		__res_pquery
373 #define res_nquery		__res_nquery
374 #define res_nquerydomain	__res_nquerydomain
375 #define res_nsearch		__res_nsearch
376 #define res_nsend		__res_nsend
377 #if 0
378 #define res_nsendsigned		__res_nsendsigned
379 #endif
380 #define res_nisourserver	__res_nisourserver
381 #define res_ownok		__res_ownok
382 #define res_queriesmatch	__res_queriesmatch
383 #define res_rndinit		__res_rndinit
384 #define res_randomid		__res_randomid
385 #define res_nrandomid		__res_nrandomid
386 #define sym_ntop		__sym_ntop
387 #define sym_ntos		__sym_ntos
388 #define sym_ston		__sym_ston
389 #define res_nopt		__res_nopt
390 #define res_nopt_rdata       	__res_nopt_rdata
391 #define res_ndestroy		__res_ndestroy
392 #define	res_nametoclass		__res_nametoclass
393 #define	res_nametotype		__res_nametotype
394 #define	res_setservers		__res_setservers
395 #define	res_getservers		__res_getservers
396 #if 0
397 #define	res_buildprotolist	__res_buildprotolist
398 #define	res_destroyprotolist	__res_destroyprotolist
399 #define	res_destroyservicelist	__res_destroyservicelist
400 #define	res_get_nibblesuffix	__res_get_nibblesuffix
401 #define	res_get_nibblesuffix2	__res_get_nibblesuffix2
402 #endif
403 #define	res_ourserver_p		__res_ourserver_p
404 #if 0
405 #define	res_protocolname	__res_protocolname
406 #define	res_protocolnumber	__res_protocolnumber
407 #endif
408 #define	res_send_setqhook	__res_send_setqhook
409 #define	res_send_setrhook	__res_send_setrhook
410 #if 0
411 #define	res_servicename		__res_servicename
412 #define	res_servicenumber	__res_servicenumber
413 #endif
414 __BEGIN_DECLS
415 int		res_hnok(const char *);
416 int		res_ownok(const char *);
417 int		res_mailok(const char *);
418 int		res_dnok(const char *);
419 int		sym_ston(const struct res_sym *, const char *, int *);
420 const char *	sym_ntos(const struct res_sym *, int, int *);
421 const char *	sym_ntop(const struct res_sym *, int, int *);
422 int		b64_ntop(u_char const *, size_t, char *, size_t);
423 int		b64_pton(char const *, u_char *, size_t);
424 int		loc_aton(const char *, u_char *);
425 const char *	loc_ntoa(const u_char *, char *);
426 int		dn_skipname(const u_char *, const u_char *);
427 void		putlong(u_int32_t, u_char *);
428 void		putshort(u_int16_t, u_char *);
429 #ifndef __ultrix__
430 u_int16_t	_getshort(const u_char *);
431 u_int32_t	_getlong(const u_char *);
432 #endif
433 const char *	p_class(int);
434 const char *	p_time(u_int32_t);
435 const char *	p_type(int);
436 const char *	p_rcode(int);
437 const char *	p_sockun(union res_sockaddr_union, char *, size_t);
438 const u_char *	p_cdnname(const u_char *, const u_char *, int, FILE *);
439 const u_char *	p_cdname(const u_char *, const u_char *, FILE *);
440 const u_char *	p_fqnname(const u_char *, const u_char *, int, char *, int);
441 const u_char *	p_fqname(const u_char *, const u_char *, FILE *);
442 const char *	p_option(u_long);
443 char *		p_secstodate(u_long);
444 int		dn_count_labels(const char *);
445 int		dn_comp(const char *, u_char *, int, u_char **, u_char **);
446 int		dn_expand(const u_char *, const u_char *, const u_char *,
447 			  char *, int);
448 void		res_rndinit(res_state);
449 u_int		res_randomid(void);
450 u_int		res_nrandomid(res_state);
451 int		res_nameinquery(const char *, int, int, const u_char *,
452 				const u_char *);
453 int		res_queriesmatch(const u_char *, const u_char *,
454 				 const u_char *, const u_char *);
455 const char *	p_section(int, int);
456 /* Things involving a resolver context. */
457 int		res_ninit(res_state);
458 int		res_nisourserver(const res_state, const struct sockaddr_in *);
459 void		fp_resstat(const res_state, FILE *);
460 void		res_pquery(const res_state, const u_char *, int, FILE *);
461 const char *	res_hostalias(const res_state, const char *, char *, size_t);
462 int		res_nquery(res_state, const char *, int, int, u_char *, int);
463 int		res_nsearch(res_state, const char *, int, int, u_char *, int);
464 int		res_nquerydomain(res_state, const char *, const char *,
465 				 int, int, u_char *, int);
466 int		res_nmkquery(res_state, int, const char *, int, int,
467 			     const u_char *, int, const u_char *,
468 			     u_char *, int);
469 int		res_nsend(res_state, const u_char *, int, u_char *, int);
470 #if 0
471 int		res_nsendsigned(res_state, const u_char *, int,
472 				ns_tsig_key *, u_char *, int);
473 int		res_findzonecut(res_state, const char *, ns_class, int,
474 				char *, size_t, struct in_addr *, int);
475 #endif
476 int		res_findzonecut2(res_state, const char *, ns_class, int,
477 				 char *, size_t,
478 				 union res_sockaddr_union *, int);
479 void		res_nclose(res_state);
480 int		res_nopt(res_state, int, u_char *, int, int);
481 int		res_nopt_rdata(res_state, int, u_char *, int, u_char *,
482 			       u_short, u_short, u_char *);
483 void		res_send_setqhook(res_send_qhook);
484 void		res_send_setrhook(res_send_rhook);
485 int		__res_vinit(res_state, int);
486 #if 0
487 void		res_destroyservicelist(void);
488 const char *	res_servicename(u_int16_t, const char *);
489 const char *	res_protocolname(int);
490 void		res_destroyprotolist(void);
491 void		res_buildprotolist(void);
492 const char *	res_get_nibblesuffix(res_state);
493 const char *	res_get_nibblesuffix2(res_state);
494 #endif
495 void		res_ndestroy(res_state);
496 u_int16_t	res_nametoclass(const char *, int *);
497 u_int16_t	res_nametotype(const char *, int *);
498 void		res_setservers(res_state, const union res_sockaddr_union *,
499 			       int);
500 int		res_getservers(res_state, union res_sockaddr_union *, int);
501 __END_DECLS
502 
503 #endif /* !_RESOLV_H_ */
504 /*! \file */
505