Commit | Line | Data |
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f3efc943 | 1 | /* |
2 | * adns.h | |
5448fc9f | 3 | * - adns user-visible API |
f3efc943 | 4 | */ |
5bb95567 | 5 | /* |
a79ac5ba | 6 | * |
7 | * This file is | |
39f45e7e | 8 | * Copyright (C) 1997-2000,2003,2006 Ian Jackson |
a79ac5ba | 9 | * |
10 | * It is part of adns, which is | |
39f45e7e | 11 | * Copyright (C) 1997-2000,2003,2006 Ian Jackson |
12 | * Copyright (C) 1999-2000,2003,2006 Tony Finch | |
13 | * Copyright (C) 1991 Massachusetts Institute of Technology | |
14 | * | |
98db6da3 | 15 | * This program is free software; you can redistribute it and/or modify |
16 | * it under the terms of the GNU General Public License as published by | |
17 | * the Free Software Foundation; either version 2, or (at your option) | |
18 | * any later version. | |
19 | * | |
20 | * This program is distributed in the hope that it will be useful, | |
21 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
22 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
23 | * GNU General Public License for more details. | |
a79ac5ba | 24 | * |
25 | * | |
c6826df6 | 26 | * For the benefit of certain LGPL'd `omnibus' software which |
27 | * provides a uniform interface to various things including adns, I | |
28 | * make the following additional licence. I do this because the GPL | |
29 | * would otherwise force either the omnibus software to be GPL'd or | |
30 | * the adns-using part to be distributed separately. | |
a79ac5ba | 31 | * |
c6826df6 | 32 | * So: you may also redistribute and/or modify adns.h (but only the |
a79ac5ba | 33 | * public header file adns.h and not any other part of adns) under the |
34 | * terms of the GNU Library General Public License as published by the | |
35 | * Free Software Foundation; either version 2 of the License, or (at | |
36 | * your option) any later version. | |
98db6da3 | 37 | * |
a79ac5ba | 38 | * Note that adns itself is GPL'd. Authors of adns-using applications |
39 | * with GPL-incompatible licences, and people who distribute adns with | |
40 | * applications where the whole distribution is not GPL'd, are still | |
41 | * likely to be in violation of the GPL. Anyone who wants to do this | |
42 | * should contact Ian Jackson. Please note that to avoid encouraging | |
c6826df6 | 43 | * people to infringe the GPL as it applies to the body of adns, Ian |
44 | * thinks that if you take advantage of the special exception to | |
45 | * redistribute just adns.h under the LGPL, you should retain this | |
46 | * paragraph in its place in the appropriate copyright statements. | |
a79ac5ba | 47 | * |
48 | * | |
49 | * You should have received a copy of the GNU General Public License, | |
50 | * or the GNU Library General Public License, as appropriate, along | |
51 | * with this program; if not, write to the Free Software Foundation, | |
3ff64957 | 52 | * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
53 | * | |
a79ac5ba | 54 | * |
5448fc9f | 55 | * $Id: adns.h,v 1.96 2006/08/09 11:16:59 ian Exp $ |
5bb95567 | 56 | */ |
5db99a2e | 57 | |
58 | #ifndef ADNS_H_INCLUDED | |
59 | #define ADNS_H_INCLUDED | |
60 | ||
d05cc330 | 61 | #include <stdio.h> |
86ea5e62 | 62 | #include <stdarg.h> |
d05cc330 | 63 | |
62ef4703 | 64 | #include <sys/types.h> |
e7afa27f | 65 | #include <sys/socket.h> |
66 | #include <netinet/in.h> | |
125de2a9 | 67 | #include <sys/time.h> |
68 | #include <unistd.h> | |
e7afa27f | 69 | |
368c83e4 | 70 | #ifdef __cplusplus |
71 | extern "C" { /* I really dislike this - iwj. */ | |
72 | #endif | |
73 | ||
8c3aa944 | 74 | /* All struct in_addr anywhere in adns are in NETWORK byte order. */ |
75 | ||
e7afa27f | 76 | typedef struct adns__state *adns_state; |
77 | typedef struct adns__query *adns_query; | |
5db99a2e | 78 | |
7a1f00f7 | 79 | typedef enum { /* In general, or together the desired flags: */ |
80 | adns_if_none= 0x0000,/* no flags. nicer than 0 for some compilers */ | |
7aac35cd | 81 | adns_if_noenv= 0x0001,/* do not look at environment */ |
82 | adns_if_noerrprint= 0x0002,/* never print to stderr (_debug overrides) */ | |
83 | adns_if_noserverwarn=0x0004,/* do not warn to stderr about duff servers etc */ | |
84 | adns_if_debug= 0x0008,/* enable all output to stderr plus debug msgs */ | |
85 | adns_if_logpid= 0x0080,/* include pid in diagnostic output */ | |
86 | adns_if_noautosys= 0x0010,/* do not make syscalls at every opportunity */ | |
87 | adns_if_eintr= 0x0020,/* allow _wait and _synchronous to return EINTR */ | |
88 | adns_if_nosigpipe= 0x0040,/* applic has SIGPIPE ignored, do not protect */ | |
89 | adns_if_checkc_entex=0x0100,/* consistency checks on entry/exit to adns fns */ | |
90 | adns_if_checkc_freq= 0x0300 /* consistency checks very frequently (slow!) */ | |
5db99a2e | 91 | } adns_initflags; |
92 | ||
7a1f00f7 | 93 | typedef enum { /* In general, or together the desired flags: */ |
94 | adns_qf_none= 0x00000000,/* no flags */ | |
7aac35cd | 95 | adns_qf_search= 0x00000001,/* use the searchlist */ |
96 | adns_qf_usevc= 0x00000002,/* use a virtual circuit (TCP conn) */ | |
97 | adns_qf_owner= 0x00000004,/* fill in the owner field in the answer */ | |
98 | adns_qf_quoteok_query= 0x00000010,/* allow special chars in query domain */ | |
99 | adns_qf_quoteok_cname= 0x00000000,/* ... in CNAME we go via (now default) */ | |
100 | adns_qf_quoteok_anshost=0x00000040,/* ... in things supposedly hostnames */ | |
101 | adns_qf_quotefail_cname=0x00000080,/* refuse if quote-req chars in CNAME we go via */ | |
102 | adns_qf_cname_loose= 0x00000100,/* allow refs to CNAMEs - without, get _s_cname */ | |
103 | adns_qf_cname_forbid= 0x00000200,/* don't follow CNAMEs, instead give _s_cname */ | |
104 | adns__qf_internalmask= 0x0ff00000 | |
5db99a2e | 105 | } adns_queryflags; |
106 | ||
107 | typedef enum { | |
7d0aaee4 | 108 | adns_rrt_typemask= 0x0ffff, |
3db6be73 | 109 | adns__qtf_deref= 0x10000,/* dereference domains; perhaps get extra data */ |
110 | adns__qtf_mail822= 0x20000,/* return mailboxes in RFC822 rcpt field fmt */ | |
ba2dbede | 111 | |
112 | adns_r_unknown= 0x40000, | |
113 | /* To use this, ask for records of type <rr-type-code>|adns_r_unknown. | |
7d0aaee4 | 114 | * adns will not process the RDATA - you'll get adns_rr_byteblocks, |
115 | * where the int is the length and the unsigned char* points to the | |
116 | * data. String representation of the RR data (by adns_rrinfo) is as in | |
117 | * RFC3597. adns_rr_info will not return the type name in *rrtname_r | |
118 | * (due to memory management problems); *fmtname_r will be set to | |
119 | * "unknown". | |
ba2dbede | 120 | * |
121 | * Do not specify adns_r_unknown along with a known RR type which | |
7d0aaee4 | 122 | * requires domain name uncompression (see RFC3597 s4); domain names |
123 | * will not be uncompressed and the resulting data would be useless. | |
124 | * Asking for meta-RR types via adns_r_unknown will not work properly | |
125 | * either and may make adns complain about server misbehaviour, so don't | |
126 | * do that. | |
127 | * | |
128 | * Don't forget adns_qf_quoteok if that's what you want. */ | |
129 | ||
7aac35cd | 130 | adns_r_none= 0, |
131 | ||
132 | adns_r_a= 1, | |
133 | ||
134 | adns_r_ns_raw= 2, | |
135 | adns_r_ns= adns_r_ns_raw|adns__qtf_deref, | |
136 | ||
137 | adns_r_cname= 5, | |
138 | ||
139 | adns_r_soa_raw= 6, | |
140 | adns_r_soa= adns_r_soa_raw|adns__qtf_mail822, | |
141 | ||
4f6dbe69 | 142 | adns_r_ptr_raw= 12, /* do not mind PTR with wrong or missing A */ |
7aac35cd | 143 | adns_r_ptr= adns_r_ptr_raw|adns__qtf_deref, |
144 | ||
145 | adns_r_hinfo= 13, | |
146 | ||
147 | adns_r_mx_raw= 15, | |
148 | adns_r_mx= adns_r_mx_raw|adns__qtf_deref, | |
149 | ||
150 | adns_r_txt= 16, | |
151 | ||
152 | adns_r_rp_raw= 17, | |
153 | adns_r_rp= adns_r_rp_raw|adns__qtf_mail822, | |
3db6be73 | 154 | |
9136cf0c MW |
155 | adns_r_aaaa= 28, |
156 | ||
3db6be73 | 157 | /* For SRV records, query domain without _qf_quoteok_query must look |
158 | * as expected from SRV RFC with hostname-like Name. _With_ | |
159 | * _quoteok_query, any query domain is allowed. */ | |
160 | adns_r_srv_raw= 33, | |
161 | adns_r_srv= adns_r_srv_raw|adns__qtf_deref, | |
7aac35cd | 162 | |
163 | adns_r_addr= adns_r_a|adns__qtf_deref | |
164 | ||
5db99a2e | 165 | } adns_rrtype; |
166 | ||
0872e289 | 167 | /* |
168 | * In queries without qf_quoteok_*, all domains must have standard | |
169 | * legal syntax, or you get adns_s_querydomainvalid (if the query | |
170 | * domain contains bad characters) or adns_s_answerdomaininvalid (if | |
171 | * the answer contains bad characters). | |
172 | * | |
173 | * In queries _with_ qf_quoteok_*, domains in the query or response | |
174 | * may contain any characters, quoted according to RFC1035 5.1. On | |
175 | * input to adns, the char* is a pointer to the interior of a " | |
996e3b68 | 176 | * delimited string, except that " may appear in it unquoted. On |
177 | * output, the char* is a pointer to a string which would be legal | |
178 | * either inside or outside " delimiters; any character which isn't | |
179 | * legal in a hostname (ie alphanumeric or hyphen) or one of _ / + | |
180 | * (the three other punctuation characters commonly abused in domain | |
181 | * names) will be quoted, as \X if it is a printing ASCII character or | |
182 | * \DDD otherwise. | |
183 | * | |
0872e289 | 184 | * If the query goes via a CNAME then the canonical name (ie, the |
185 | * thing that the CNAME record refers to) is usually allowed to | |
186 | * contain any characters, which will be quoted as above. With | |
187 | * adns_qf_quotefail_cname you get adns_s_answerdomaininvalid when | |
188 | * this happens. (This is a change from version 0.4 and earlier, in | |
189 | * which failing the query was the default, and you had to say | |
190 | * adns_qf_quoteok_cname to avoid this; that flag is now deprecated.) | |
191 | * | |
192 | * In version 0.4 and earlier, asking for _raw records containing | |
193 | * mailboxes without specifying _qf_quoteok_anshost was silly. This | |
194 | * is no longer the case. In this version only parts of responses | |
195 | * that are actually supposed to be hostnames will be refused by | |
196 | * default if quote-requiring characters are found. | |
197 | */ | |
198 | ||
199 | /* | |
200 | * If you ask for an RR which contains domains which are actually | |
201 | * encoded mailboxes, and don't ask for the _raw version, then adns | |
202 | * returns the mailbox formatted suitably for an RFC822 recipient | |
203 | * header field. The particular format used is that if the mailbox | |
204 | * requires quoting according to the rules in RFC822 then the | |
205 | * local-part is quoted in double quotes, which end at the next | |
67ca39c8 | 206 | * unescaped double quote (\ is the escape char, and is doubled, and |
207 | * is used to escape only \ and "). If the local-part is legal | |
208 | * without quoting according to RFC822, it is presented as-is. In any | |
209 | * case the local-part is followed by an @ and the domain. The domain | |
210 | * will not contain any characters not legal in hostnames. | |
211 | * | |
212 | * Unquoted local-parts may contain any printing 7-bit ASCII | |
213 | * except the punctuation characters ( ) < > @ , ; : \ " [ ] | |
214 | * I.e. they may contain alphanumerics, and the following | |
215 | * punctuation characters: ! # % ^ & * - _ = + { } . | |
216 | * | |
217 | * adns will reject local parts containing control characters (byte | |
218 | * values 0-31, 127-159, and 255) - these appear to be legal according | |
abf5f52c | 219 | * to RFC822 (at least 0-127) but are clearly a bad idea. RFC1035 |
220 | * syntax does not make any distinction between a single RFC822 | |
221 | * quoted-string containing full stops, and a series of quoted-strings | |
222 | * separated by full stops; adns will return anything that isn't all | |
223 | * valid atoms as a single quoted-string. RFC822 does not allow | |
224 | * high-bit-set characters at all, but adns does allow them in | |
225 | * local-parts, treating them as needing quoting. | |
0872e289 | 226 | * |
227 | * If you ask for the domain with _raw then _no_ checking is done | |
228 | * (even on the host part, regardless of adns_qf_quoteok_anshost), and | |
229 | * you just get the domain name in master file format. | |
230 | * | |
231 | * If no mailbox is supplied the returned string will be `.' in either | |
abf5f52c | 232 | * case. |
e7afa27f | 233 | */ |
234 | ||
5db99a2e | 235 | typedef enum { |
7aac35cd | 236 | adns_s_ok, |
237 | ||
238 | /* locally induced errors */ | |
239 | adns_s_nomemory, | |
240 | adns_s_unknownrrtype, | |
241 | adns_s_systemfail, | |
242 | ||
243 | adns_s_max_localfail= 29, | |
244 | ||
245 | /* remotely induced errors, detected locally */ | |
246 | adns_s_timeout, | |
247 | adns_s_allservfail, | |
248 | adns_s_norecurse, | |
249 | adns_s_invalidresponse, | |
250 | adns_s_unknownformat, | |
251 | ||
252 | adns_s_max_remotefail= 59, | |
253 | ||
254 | /* remotely induced errors, reported by remote server to us */ | |
255 | adns_s_rcodeservfail, | |
256 | adns_s_rcodeformaterror, | |
257 | adns_s_rcodenotimplemented, | |
258 | adns_s_rcoderefused, | |
259 | adns_s_rcodeunknown, | |
260 | ||
261 | adns_s_max_tempfail= 99, | |
262 | ||
263 | /* remote configuration errors */ | |
264 | adns_s_inconsistent, /* PTR gives domain whose A does not exist and match */ | |
265 | adns_s_prohibitedcname, /* CNAME, but eg A expected (not if _qf_loosecname) */ | |
266 | adns_s_answerdomaininvalid, | |
267 | adns_s_answerdomaintoolong, | |
268 | adns_s_invaliddata, | |
269 | ||
270 | adns_s_max_misconfig= 199, | |
271 | ||
272 | /* permanent problems with the query */ | |
273 | adns_s_querydomainwrong, | |
274 | adns_s_querydomaininvalid, | |
275 | adns_s_querydomaintoolong, | |
276 | ||
277 | adns_s_max_misquery= 299, | |
278 | ||
279 | /* permanent errors */ | |
280 | adns_s_nxdomain, | |
281 | adns_s_nodata, | |
282 | ||
283 | adns_s_max_permfail= 499 | |
284 | ||
5db99a2e | 285 | } adns_status; |
286 | ||
cd363ffd | 287 | typedef struct { |
288 | int len; | |
289 | union { | |
290 | struct sockaddr sa; | |
291 | struct sockaddr_in inet; | |
292 | } addr; | |
bc01473e | 293 | } adns_rr_addr; |
cd363ffd | 294 | |
6927715a | 295 | typedef struct { |
26eb6bdc | 296 | char *host; |
6927715a | 297 | adns_status astatus; |
298 | int naddrs; /* temp fail => -1, perm fail => 0, s_ok => >0 */ | |
bc01473e | 299 | adns_rr_addr *addrs; |
a1d2d0ed | 300 | } adns_rr_hostaddr; |
d05cc330 | 301 | |
302 | typedef struct { | |
61093792 | 303 | char *(array[2]); |
d05cc330 | 304 | } adns_rr_strpair; |
305 | ||
306 | typedef struct { | |
307 | int i; | |
26eb6bdc | 308 | adns_rr_hostaddr ha; |
a1d2d0ed | 309 | } adns_rr_inthostaddr; |
d05cc330 | 310 | |
311 | typedef struct { | |
7aac35cd | 312 | /* Used both for mx_raw, in which case i is the preference and str |
313 | * the domain, and for txt, in which case each entry has i for the | |
314 | * `text' length, and str for the data (which will have had an extra | |
315 | * nul appended so that if it was plain text it is now a | |
316 | * null-terminated string). | |
f2ad23ee | 317 | */ |
d05cc330 | 318 | int i; |
319 | char *str; | |
320 | } adns_rr_intstr; | |
321 | ||
322 | typedef struct { | |
61093792 | 323 | adns_rr_intstr array[2]; |
324 | } adns_rr_intstrpair; | |
325 | ||
326 | typedef struct { | |
327 | char *mname, *rname; | |
d05cc330 | 328 | unsigned long serial, refresh, retry, expire, minimum; |
329 | } adns_rr_soa; | |
6927715a | 330 | |
3db6be73 | 331 | typedef struct { |
332 | int priority, weight, port; | |
333 | char *host; | |
334 | } adns_rr_srvraw; | |
335 | ||
336 | typedef struct { | |
337 | int priority, weight, port; | |
338 | adns_rr_hostaddr ha; | |
2248cdf4 | 339 | } adns_rr_srvha; |
3db6be73 | 340 | |
7d0aaee4 | 341 | typedef struct { |
342 | int len; | |
343 | unsigned char *data; | |
344 | } adns_rr_byteblock; | |
345 | ||
5617a135 | 346 | typedef struct { |
5db99a2e | 347 | adns_status status; |
348 | char *cname; /* always NULL if query was for CNAME records */ | |
7aac35cd | 349 | char *owner; /* only set if req'd in query flags; maybe 0 on error anyway */ |
1e9efa71 | 350 | adns_rrtype type; /* guaranteed to be same as in query */ |
7aac35cd | 351 | time_t expires;/*abs time. def only if _s_ok, nxdomain or nodata. NOT TTL!*/ |
0872e289 | 352 | int nrrs, rrsz; /* nrrs is 0 if an error occurs */ |
5db99a2e | 353 | union { |
965c9782 | 354 | void *untyped; |
355 | unsigned char *bytes; | |
7aac35cd | 356 | char *(*str); /* ns_raw, cname, ptr, ptr_raw */ |
357 | adns_rr_intstr *(*manyistr); /* txt (list strs ends with i=-1, str=0)*/ | |
358 | adns_rr_addr *addr; /* addr */ | |
359 | struct in_addr *inaddr; /* a */ | |
9136cf0c | 360 | struct in6_addr *in6addr; /* aaaa */ |
7aac35cd | 361 | adns_rr_hostaddr *hostaddr; /* ns */ |
362 | adns_rr_intstrpair *intstrpair; /* hinfo */ | |
363 | adns_rr_strpair *strpair; /* rp, rp_raw */ | |
364 | adns_rr_inthostaddr *inthostaddr;/* mx */ | |
7d0aaee4 | 365 | adns_rr_intstr *intstr; /* mx_raw */ |
7aac35cd | 366 | adns_rr_soa *soa; /* soa, soa_raw */ |
3db6be73 | 367 | adns_rr_srvraw *srvraw; /* srv_raw */ |
2248cdf4 | 368 | adns_rr_srvha *srvha;/* srv */ |
7d0aaee4 | 369 | adns_rr_byteblock *byteblock; /* ...|unknown */ |
5db99a2e | 370 | } rrs; |
5617a135 | 371 | } adns_answer; |
5db99a2e | 372 | |
373 | /* Memory management: | |
374 | * adns_state and adns_query are actually pointers to malloc'd state; | |
375 | * On submission questions are copied, including the owner domain; | |
d05cc330 | 376 | * Answers are malloc'd as a single piece of memory; pointers in the |
377 | * answer struct point into further memory in the answer. | |
5db99a2e | 378 | * query_io: |
379 | * Must always be non-null pointer; | |
380 | * If *query_io is 0 to start with then any query may be returned; | |
381 | * If *query_io is !0 adns_query then only that query may be returned. | |
9be46d86 | 382 | * If the call is successful, *query_io, *answer_r, and *context_r |
383 | * will all be set. | |
5db99a2e | 384 | * Errors: |
74c94831 | 385 | * Return values are 0 or an errno value. |
386 | * | |
387 | * For _init, _init_strcfg, _submit and _synchronous, system errors | |
388 | * (eg, failure to create sockets, malloc failure, etc.) return errno | |
032b6358 | 389 | * values. EINVAL from _init et al means the configuration file |
390 | * is erroneous and cannot be parsed. | |
74c94831 | 391 | * |
392 | * For _wait and _check failures are reported in the answer | |
c6f9dc7b | 393 | * structure, and only 0, ESRCH or (for _check) EAGAIN is |
74c94831 | 394 | * returned: if no (appropriate) requests are done adns_check returns |
c6f9dc7b | 395 | * EAGAIN; if no (appropriate) requests are outstanding both |
74c94831 | 396 | * adns_query and adns_wait return ESRCH. |
397 | * | |
398 | * Additionally, _wait can return EINTR if you set adns_if_eintr. | |
399 | * | |
400 | * All other errors (nameserver failure, timed out connections, &c) | |
401 | * are returned in the status field of the answer. After a | |
402 | * successful _wait or _check, if status is nonzero then nrrs will be | |
403 | * 0, otherwise it will be >0. type will always be the type | |
404 | * requested. | |
5db99a2e | 405 | */ |
406 | ||
5448fc9f | 407 | /* Threads: |
408 | * adns does not use any static modifiable state, so it | |
409 | * is safe to call adns_init several times and then use the | |
410 | * resulting adns_states concurrently. | |
411 | * However, it is NOT safe to make simultaneous calls into | |
412 | * adns using the same adns_state; a single adns_state must be used | |
413 | * only by one thread at a time. You can solve this problem by | |
414 | * having one adns_state per thread, or if that isn't feasible, you | |
415 | * could maintain a pool of adns_states. Unfortunately neither of | |
416 | * these approaches has optimal performance. | |
417 | */ | |
418 | ||
edb95764 | 419 | int adns_init(adns_state *newstate_r, adns_initflags flags, |
d6b271ae | 420 | FILE *diagfile /*0=>stderr*/); |
421 | ||
edb95764 | 422 | int adns_init_strcfg(adns_state *newstate_r, adns_initflags flags, |
d6b271ae | 423 | FILE *diagfile /*0=>discard*/, const char *configtext); |
38fcb64a | 424 | |
86ea5e62 | 425 | typedef void adns_logcallbackfn(adns_state ads, void *logfndata, |
426 | const char *fmt, va_list al); | |
427 | /* Will be called perhaps several times for each message; when the | |
428 | * message is complete, the string implied by fmt and al will end in | |
429 | * a newline. Log messages start with `adns debug:' or `adns | |
430 | * warning:' or `adns:' (for errors), or `adns debug [PID]:' | |
431 | * etc. if adns_if_logpid is set. */ | |
432 | ||
433 | int adns_init_logfn(adns_state *newstate_r, adns_initflags flags, | |
434 | const char *configtext /*0=>use default config files*/, | |
435 | adns_logcallbackfn *logfn /*0=>logfndata is a FILE* */, | |
436 | void *logfndata /*0 with logfn==0 => discard*/); | |
437 | ||
38fcb64a | 438 | /* Configuration: |
439 | * adns_init reads /etc/resolv.conf, which is expected to be (broadly | |
45efc92a | 440 | * speaking) in the format expected by libresolv, and then |
441 | * /etc/resolv-adns.conf if it exists. adns_init_strcfg is instead | |
442 | * passed a string which is interpreted as if it were the contents of | |
443 | * resolv.conf or resolv-adns.conf. In general, configuration which | |
444 | * is set later overrides any that is set earlier. | |
38fcb64a | 445 | * |
45efc92a | 446 | * Standard directives understood in resolv[-adns].conf: |
38fcb64a | 447 | * |
448 | * nameserver <address> | |
449 | * Must be followed by the IP address of a nameserver. Several | |
450 | * nameservers may be specified, and they will be tried in the order | |
451 | * found. There is a compiled in limit, currently 5, on the number | |
452 | * of nameservers. (libresolv supports only 3 nameservers.) | |
453 | * | |
454 | * search <domain> ... | |
455 | * Specifies the search list for queries which specify | |
456 | * adns_qf_search. This is a list of domains to append to the query | |
457 | * domain. The query domain will be tried as-is either before all | |
458 | * of these or after them, depending on the ndots option setting | |
459 | * (see below). | |
460 | * | |
461 | * domain <domain> | |
462 | * This is present only for backward compatibility with obsolete | |
463 | * versions of libresolv. It should not be used, and is interpreted | |
464 | * by adns as if it were `search' - note that this is subtly | |
465 | * different to libresolv's interpretation of this directive. | |
466 | * | |
467 | * sortlist <addr>/<mask> ... | |
468 | * Should be followed by a sequence of IP-address and netmask pairs, | |
469 | * separated by spaces. They may be specified as | |
470 | * eg. 172.30.206.0/24 or 172.30.206.0/255.255.255.0. Currently up | |
471 | * to 15 pairs may be specified (but note that libresolv only | |
472 | * supports up to 10). | |
473 | * | |
474 | * options | |
475 | * Should followed by one or more options, separated by spaces. | |
476 | * Each option consists of an option name, followed by optionally | |
477 | * a colon and a value. Options are listed below. | |
478 | * | |
45efc92a | 479 | * Non-standard directives understood in resolv[-adns].conf: |
38fcb64a | 480 | * |
481 | * clearnameservers | |
482 | * Clears the list of nameservers, so that further nameserver lines | |
483 | * start again from the beginning. | |
484 | * | |
485 | * include <filename> | |
486 | * The specified file will be read. | |
487 | * | |
45efc92a | 488 | * Additionally, adns will ignore lines in resolv[-adns].conf which |
489 | * start with a #. | |
38fcb64a | 490 | * |
491 | * Standard options understood: | |
492 | * | |
493 | * debug | |
494 | * Enables debugging output from the resolver, which will be written | |
495 | * to stderr. | |
496 | * | |
497 | * ndots:<count> | |
498 | * Affects whether queries with adns_qf_search will be tried first | |
499 | * without adding domains from the searchlist, or whether the bare | |
500 | * query domain will be tried last. Queries which contain at least | |
501 | * <count> dots will be tried bare first. The default is 1. | |
502 | * | |
503 | * Non-standard options understood: | |
504 | * | |
505 | * adns_checkc:none | |
506 | * adns_checkc:entex | |
507 | * adns_checkc:freq | |
508 | * Changes the consistency checking frequency; this overrides the | |
509 | * setting of adns_if_check_entex, adns_if_check_freq, or neither, | |
510 | * in the flags passed to adns_init. | |
511 | * | |
512 | * There are a number of environment variables which can modify the | |
513 | * behaviour of adns. They take effect only if adns_init is used, and | |
514 | * the caller of adns_init can disable them using adns_if_noenv. In | |
515 | * each case there is both a FOO and an ADNS_FOO; the latter is | |
516 | * interpreted later so that it can override the former. Unless | |
517 | * otherwise stated, environment variables are interpreted after | |
45efc92a | 518 | * resolv[-adns].conf are read, in the order they are listed here. |
38fcb64a | 519 | * |
520 | * RES_CONF, ADNS_RES_CONF | |
521 | * A filename, whose contets are in the format of resolv.conf. | |
522 | * | |
523 | * RES_CONF_TEXT, ADNS_RES_CONF_TEXT | |
524 | * A string in the format of resolv.conf. | |
525 | * | |
526 | * RES_OPTIONS, ADNS_RES_OPTIONS | |
527 | * These are parsed as if they appeared in the `options' line of a | |
528 | * resolv.conf. In addition to being parsed at this point in the | |
529 | * sequence, they are also parsed at the very beginning before | |
530 | * resolv.conf or any other environment variables are read, so that | |
531 | * any debug option can affect the processing of the configuration. | |
532 | * | |
533 | * LOCALDOMAIN, ADNS_LOCALDOMAIN | |
534 | * These are interpreted as if their contents appeared in a `search' | |
535 | * line in resolv.conf. | |
536 | */ | |
5db99a2e | 537 | |
538 | int adns_synchronous(adns_state ads, | |
539 | const char *owner, | |
540 | adns_rrtype type, | |
edb95764 | 541 | adns_queryflags flags, |
9ab4dfce | 542 | adns_answer **answer_r); |
5617a135 | 543 | |
544 | /* NB: if you set adns_if_noautosys then _submit and _check do not | |
74c94831 | 545 | * make any system calls; you must use some of the asynch-io event |
546 | * processing functions to actually get things to happen. | |
5617a135 | 547 | */ |
5db99a2e | 548 | |
549 | int adns_submit(adns_state ads, | |
550 | const char *owner, | |
551 | adns_rrtype type, | |
edb95764 | 552 | adns_queryflags flags, |
5db99a2e | 553 | void *context, |
e7afa27f | 554 | adns_query *query_r); |
5db99a2e | 555 | |
bcf33879 | 556 | /* The owner should be quoted in master file format. */ |
557 | ||
e7afa27f | 558 | int adns_check(adns_state ads, |
5db99a2e | 559 | adns_query *query_io, |
9ab4dfce | 560 | adns_answer **answer_r, |
561 | void **context_r); | |
5db99a2e | 562 | |
563 | int adns_wait(adns_state ads, | |
564 | adns_query *query_io, | |
9ab4dfce | 565 | adns_answer **answer_r, |
566 | void **context_r); | |
5db99a2e | 567 | |
ef20fccf | 568 | /* same as adns_wait but uses poll(2) internally */ |
569 | int adns_wait_poll(adns_state ads, | |
570 | adns_query *query_io, | |
571 | adns_answer **answer_r, | |
572 | void **context_r); | |
573 | ||
11c8bf9b | 574 | void adns_cancel(adns_query query); |
5db99a2e | 575 | |
74c94831 | 576 | /* The adns_query you get back from _submit is valid (ie, can be |
577 | * legitimately passed into adns functions) until it is returned by | |
578 | * adns_check or adns_wait, or passed to adns_cancel. After that it | |
579 | * must not be used. You can rely on it not being reused until the | |
580 | * first adns_submit or _transact call using the same adns_state after | |
581 | * it became invalid, so you may compare it for equality with other | |
582 | * query handles until you next call _query or _transact. | |
125de2a9 | 583 | * |
584 | * _submit and _synchronous return ENOSYS if they don't understand the | |
585 | * query type. | |
74c94831 | 586 | */ |
587 | ||
0872e289 | 588 | int adns_submit_reverse(adns_state ads, |
589 | const struct sockaddr *addr, | |
590 | adns_rrtype type, | |
edb95764 | 591 | adns_queryflags flags, |
0872e289 | 592 | void *context, |
593 | adns_query *query_r); | |
5e6342f0 | 594 | /* type must be _r_ptr or _r_ptr_raw. _qf_search is ignored. |
595 | * addr->sa_family must be AF_INET or you get ENOSYS. | |
596 | */ | |
0872e289 | 597 | |
d2f6d877 | 598 | int adns_submit_reverse_any(adns_state ads, |
599 | const struct sockaddr *addr, | |
600 | const char *rzone, | |
601 | adns_rrtype type, | |
602 | adns_queryflags flags, | |
603 | void *context, | |
604 | adns_query *query_r); | |
605 | /* For RBL-style reverse `zone's; look up | |
606 | * <reversed-address>.<zone> | |
607 | * Any type is allowed. _qf_search is ignored. | |
608 | * addr->sa_family must be AF_INET or you get ENOSYS. | |
609 | */ | |
610 | ||
74c94831 | 611 | void adns_finish(adns_state ads); |
98db6da3 | 612 | /* You may call this even if you have queries outstanding; |
613 | * they will be cancelled. | |
614 | */ | |
5db99a2e | 615 | |
e7afa27f | 616 | |
23dca174 | 617 | void adns_forallqueries_begin(adns_state ads); |
8f2aa812 | 618 | adns_query adns_forallqueries_next(adns_state ads, void **context_r); |
74c94831 | 619 | /* Iterator functions, which you can use to loop over the outstanding |
23dca174 | 620 | * (submitted but not yet successfuly checked/waited) queries. |
74c94831 | 621 | * |
23dca174 | 622 | * You can only have one iteration going at once. You may call _begin |
623 | * at any time; after that, an iteration will be in progress. You may | |
624 | * only call _next when an iteration is in progress - anything else | |
625 | * may coredump. The iteration remains in progress until _next | |
626 | * returns 0, indicating that all the queries have been walked over, | |
627 | * or ANY other adns function is called with the same adns_state (or a | |
628 | * query in the same adns_state). There is no need to explicitly | |
629 | * finish an iteration. | |
630 | * | |
8f2aa812 | 631 | * context_r may be 0. *context_r may not be set when _next returns 0. |
e7afa27f | 632 | */ |
5db99a2e | 633 | |
2ac463bf | 634 | void adns_checkconsistency(adns_state ads, adns_query qu); |
1389dc72 | 635 | /* Checks the consistency of adns's internal data structures. |
636 | * If any error is found, the program will abort(). | |
2ac463bf | 637 | * You may pass 0 for qu; if you pass non-null then additional checks |
638 | * are done to make sure that qu is a valid query. | |
1389dc72 | 639 | */ |
640 | ||
74c94831 | 641 | /* |
642 | * Example expected/legal calling sequence for submit/check/wait: | |
5db99a2e | 643 | * adns_init |
644 | * adns_submit 1 | |
645 | * adns_submit 2 | |
646 | * adns_submit 3 | |
647 | * adns_wait 1 | |
c6f9dc7b | 648 | * adns_check 3 -> EAGAIN |
5db99a2e | 649 | * adns_wait 2 |
650 | * adns_wait 3 | |
651 | * .... | |
652 | * adns_finish | |
74c94831 | 653 | */ |
654 | ||
655 | /* | |
656 | * Entrypoints for generic asynch io: | |
657 | * (these entrypoints are not very useful except in combination with * | |
658 | * some of the other I/O model calls which can tell you which fds to | |
659 | * be interested in): | |
660 | * | |
661 | * Note that any adns call may cause adns to open and close fds, so | |
662 | * you must call beforeselect or beforepoll again just before | |
663 | * blocking, or you may not have an up-to-date list of it's fds. | |
664 | */ | |
665 | ||
666 | int adns_processany(adns_state ads); | |
667 | /* Gives adns flow-of-control for a bit. This will never block, and | |
668 | * can be used with any threading/asynch-io model. If some error | |
669 | * occurred which might cause an event loop to spin then the errno | |
670 | * value is returned. | |
671 | */ | |
672 | ||
673 | int adns_processreadable(adns_state ads, int fd, const struct timeval *now); | |
674 | int adns_processwriteable(adns_state ads, int fd, const struct timeval *now); | |
675 | int adns_processexceptional(adns_state ads, int fd, const struct timeval *now); | |
676 | /* Gives adns flow-of-control so that it can process incoming data | |
677 | * from, or send outgoing data via, fd. Very like _processany. If it | |
678 | * returns zero then fd will no longer be readable or writeable | |
679 | * (unless of course more data has arrived since). adns will _only_ | |
7a1ae5ac | 680 | * use that fd and only in the manner specified, regardless of whether |
74c94831 | 681 | * adns_if_noautosys was specified. |
682 | * | |
683 | * adns_processexceptional should be called when select(2) reports an | |
684 | * exceptional condition, or poll(2) reports POLLPRI. | |
685 | * | |
686 | * It is fine to call _processreabable or _processwriteable when the | |
687 | * fd is not ready, or with an fd that doesn't belong to adns; it will | |
688 | * then just return 0. | |
689 | * | |
690 | * If some error occurred which might prevent an event loop to spin | |
691 | * then the errno value is returned. | |
692 | */ | |
693 | ||
694 | void adns_processtimeouts(adns_state ads, const struct timeval *now); | |
695 | /* Gives adns flow-of-control so that it can process any timeouts | |
696 | * which might have happened. Very like _processreadable/writeable. | |
697 | * | |
698 | * now may be 0; if it isn't, *now must be the current time, recently | |
699 | * obtained from gettimeofday. | |
700 | */ | |
701 | ||
702 | void adns_firsttimeout(adns_state ads, | |
703 | struct timeval **tv_mod, struct timeval *tv_buf, | |
704 | struct timeval now); | |
705 | /* Asks adns when it would first like the opportunity to time | |
706 | * something out. now must be the current time, from gettimeofday. | |
707 | * | |
708 | * If tv_mod points to 0 then tv_buf must be non-null, and | |
709 | * _firsttimeout will fill in *tv_buf with the time until the first | |
710 | * timeout, and make *tv_mod point to tv_buf. If adns doesn't have | |
711 | * anything that might need timing out it will leave *tv_mod as 0. | |
712 | * | |
713 | * If *tv_mod is not 0 then tv_buf is not used. adns will update | |
714 | * *tv_mod if it has any earlier timeout, and leave it alone if it | |
715 | * doesn't. | |
716 | * | |
717 | * This call will not actually do any I/O, or change the fds that adns | |
718 | * is using. It always succeeds and never blocks. | |
719 | */ | |
720 | ||
721 | void adns_globalsystemfailure(adns_state ads); | |
722 | /* If serious problem(s) happen which globally affect your ability to | |
723 | * interact properly with adns, or adns's ability to function | |
724 | * properly, you or adns can call this function. | |
725 | * | |
726 | * All currently outstanding queries will be made to fail with | |
727 | * adns_s_systemfail, and adns will close any stream sockets it has | |
728 | * open. | |
729 | * | |
730 | * This is used by adns, for example, if gettimeofday() fails. | |
731 | * Without this the program's event loop might start to spin ! | |
732 | * | |
733 | * This call will never block. | |
734 | */ | |
735 | ||
736 | /* | |
737 | * Entrypoints for select-loop based asynch io: | |
738 | */ | |
739 | ||
740 | void adns_beforeselect(adns_state ads, int *maxfd, fd_set *readfds, | |
741 | fd_set *writefds, fd_set *exceptfds, | |
742 | struct timeval **tv_mod, struct timeval *tv_buf, | |
743 | const struct timeval *now); | |
744 | /* Find out file descriptors adns is interested in, and when it would | |
745 | * like the opportunity to time something out. If you do not plan to | |
746 | * block then tv_mod may be 0. Otherwise, tv_mod and tv_buf are as | |
747 | * for adns_firsttimeout. readfds, writefds, exceptfds and maxfd_io may | |
748 | * not be 0. | |
749 | * | |
86ea5e62 | 750 | * If tv_mod is 0 on entry then this will never actually do any I/O, |
751 | * or change the fds that adns is using or the timeouts it wants. In | |
752 | * any case it won't block, and it will set the timeout to zero if a | |
753 | * query finishes in _beforeselect. | |
74c94831 | 754 | */ |
755 | ||
756 | void adns_afterselect(adns_state ads, int maxfd, const fd_set *readfds, | |
757 | const fd_set *writefds, const fd_set *exceptfds, | |
758 | const struct timeval *now); | |
759 | /* Gives adns flow-of-control for a bit; intended for use after | |
760 | * select. This is just a fancy way of calling adns_processreadable/ | |
761 | * writeable/timeouts as appropriate, as if select had returned the | |
762 | * data being passed. Always succeeds. | |
763 | */ | |
764 | ||
765 | /* | |
766 | * Example calling sequence: | |
5db99a2e | 767 | * |
5617a135 | 768 | * adns_init _noautosys |
5db99a2e | 769 | * loop { |
74c94831 | 770 | * adns_beforeselect |
5db99a2e | 771 | * select |
74c94831 | 772 | * adns_afterselect |
5617a135 | 773 | * ... |
774 | * adns_submit / adns_check | |
775 | * ... | |
5db99a2e | 776 | * } |
777 | */ | |
778 | ||
74c94831 | 779 | /* |
780 | * Entrypoints for poll-loop based asynch io: | |
781 | */ | |
782 | ||
783 | struct pollfd; | |
784 | /* In case your system doesn't have it or you forgot to include | |
785 | * <sys/poll.h>, to stop the following declarations from causing | |
786 | * problems. If your system doesn't have poll then the following | |
787 | * entrypoints will not be defined in libadns. Sorry ! | |
788 | */ | |
789 | ||
7aac35cd | 790 | int adns_beforepoll(adns_state ads, struct pollfd *fds, |
791 | int *nfds_io, int *timeout_io, | |
74c94831 | 792 | const struct timeval *now); |
793 | /* Finds out which fd's adns is interested in, and when it would like | |
794 | * to be able to time things out. This is in a form suitable for use | |
795 | * with poll(2). | |
796 | * | |
797 | * On entry, usually fds should point to at least *nfds_io structs. | |
798 | * adns will fill up to that many structs will information for poll, | |
799 | * and record in *nfds_io how many structs it filled. If it wants to | |
800 | * listen for more structs then *nfds_io will be set to the number | |
801 | * required and _beforepoll will return ERANGE. | |
802 | * | |
74c94831 | 803 | * You may call _beforepoll with fds==0 and *nfds_io 0, in which case |
804 | * adns will fill in the number of fds that it might be interested in | |
4f973eb5 | 805 | * in *nfds_io, and always return either 0 (if it is not interested in |
806 | * any fds) or ERANGE (if it is). | |
807 | * | |
dd9cf93b | 808 | * NOTE that (unless now is 0) adns may acquire additional fds |
4f973eb5 | 809 | * from one call to the next, so you must put adns_beforepoll in a |
810 | * loop, rather than assuming that the second call (with the buffer | |
811 | * size requested by the first) will not return ERANGE. | |
74c94831 | 812 | * |
813 | * adns only ever sets POLLIN, POLLOUT and POLLPRI in its pollfd | |
814 | * structs, and only ever looks at those bits. POLLPRI is required to | |
4f973eb5 | 815 | * detect TCP Urgent Data (which should not be used by a DNS server) |
74c94831 | 816 | * so that adns can know that the TCP stream is now useless. |
817 | * | |
818 | * In any case, *timeout_io should be a timeout value as for poll(2), | |
819 | * which adns will modify downwards as required. If the caller does | |
4f973eb5 | 820 | * not plan to block then *timeout_io should be 0 on entry, or |
821 | * alternatively, timeout_io may be 0. (Alternatively, the caller may | |
822 | * use _beforeselect with timeout_io==0 to find out about file | |
823 | * descriptors, and use _firsttimeout is used to find out when adns | |
824 | * might want to time something out.) | |
74c94831 | 825 | * |
826 | * adns_beforepoll will return 0 on success, and will not fail for any | |
827 | * reason other than the fds buffer being too small (ERANGE). | |
828 | * | |
dd9cf93b | 829 | * This call will never actually do any I/O. If you supply the |
830 | * current time it will not change the fds that adns is using or the | |
831 | * timeouts it wants. | |
832 | * | |
833 | * In any case this call won't block. | |
74c94831 | 834 | */ |
835 | ||
836 | #define ADNS_POLLFDS_RECOMMENDED 2 | |
837 | /* If you allocate an fds buf with at least RECOMMENDED entries then | |
838 | * you are unlikely to need to enlarge it. You are recommended to do | |
839 | * so if it's convenient. However, you must be prepared for adns to | |
840 | * require more space than this. | |
841 | */ | |
842 | ||
843 | void adns_afterpoll(adns_state ads, const struct pollfd *fds, int nfds, | |
844 | const struct timeval *now); | |
845 | /* Gives adns flow-of-control for a bit; intended for use after | |
846 | * poll(2). fds and nfds should be the results from poll(). pollfd | |
847 | * structs mentioning fds not belonging to adns will be ignored. | |
848 | */ | |
849 | ||
850 | ||
1e9efa71 | 851 | adns_status adns_rr_info(adns_rrtype type, |
852 | const char **rrtname_r, const char **fmtname_r, | |
853 | int *len_r, | |
854 | const void *datap, char **data_r); | |
0872e289 | 855 | /* |
0872e289 | 856 | * Get information about a query type, or convert reply data to a |
857 | * textual form. type must be specified, and the official name of the | |
858 | * corresponding RR type will be returned in *rrtname_r, and | |
859 | * information about the processing style in *fmtname_r. The length | |
860 | * of the table entry in an answer for that type will be returned in | |
861 | * in *len_r. Any or all of rrtname_r, fmtname_r and len_r may be 0. | |
862 | * If fmtname_r is non-null then *fmtname_r may be null on return, | |
863 | * indicating that no special processing is involved. | |
864 | * | |
865 | * data_r be must be non-null iff datap is. In this case *data_r will | |
866 | * be set to point to a string pointing to a representation of the RR | |
867 | * data in master file format. (The owner name, timeout, class and | |
868 | * type will not be present - only the data part of the RR.) The | |
869 | * memory will have been obtained from malloc() and must be freed by | |
870 | * the caller. | |
1e9efa71 | 871 | * |
872 | * Usually this routine will succeed. Possible errors include: | |
873 | * adns_s_nomemory | |
9b86645c | 874 | * adns_s_rrtypeunknown |
1e9efa71 | 875 | * adns_s_invaliddata (*datap contained garbage) |
876 | * If an error occurs then no memory has been allocated, | |
877 | * and *rrtname_r, *fmtname_r, *len_r and *data_r are undefined. | |
0872e289 | 878 | * |
879 | * There are some adns-invented data formats which are not official | |
880 | * master file formats. These include: | |
881 | * | |
882 | * Mailboxes if __qtf_mail822: these are just included as-is. | |
883 | * | |
884 | * Addresses (adns_rr_addr): these may be of pretty much any type. | |
885 | * The representation is in two parts: first, a word for the address | |
886 | * family (ie, in AF_XXX, the XXX), and then one or more items for the | |
887 | * address itself, depending on the format. For an IPv4 address the | |
888 | * syntax is INET followed by the dotted quad (from inet_ntoa). | |
889 | * Currently only IPv4 is supported. | |
890 | * | |
0fb18816 | 891 | * Text strings (as in adns_rr_txt) appear inside double quotes, and |
892 | * use \" and \\ to represent " and \, and \xHH to represent | |
893 | * characters not in the range 32-126. | |
894 | * | |
0872e289 | 895 | * Hostname with addresses (adns_rr_hostaddr): this consists of the |
0fb18816 | 896 | * hostname, as usual, followed by the adns_status value, as an |
897 | * abbreviation, and then a descriptive string (encoded as if it were | |
898 | * a piece of text), for the address lookup, followed by zero or more | |
eaf858ea | 899 | * addresses enclosed in ( and ). If the result was a temporary |
0872e289 | 900 | * failure, then a single ? appears instead of the ( ). If the |
eaf858ea | 901 | * result was a permanent failure then an empty pair of parentheses |
0872e289 | 902 | * appears (which a space in between). For example, one of the NS |
0fb18816 | 903 | * records for greenend.org.uk comes out like |
904 | * ns.chiark.greenend.org.uk ok "OK" ( INET 195.224.76.132 ) | |
0872e289 | 905 | * an MX referring to a nonexistent host might come out like: |
0fb18816 | 906 | * 50 sun2.nsfnet-relay.ac.uk nxdomain "No such domain" ( ) |
0872e289 | 907 | * and if nameserver information is not available you might get: |
0fb18816 | 908 | * dns2.spong.dyn.ml.org timeout "DNS query timed out" ? |
1e9efa71 | 909 | */ |
910 | ||
7f702335 | 911 | const char *adns_strerror(adns_status st); |
c2875680 | 912 | const char *adns_errabbrev(adns_status st); |
9e50e3ac | 913 | const char *adns_errtypeabbrev(adns_status st); |
74c94831 | 914 | /* Like strerror but for adns_status values. adns_errabbrev returns |
915 | * the abbreviation of the error - eg, for adns_s_timeout it returns | |
9e50e3ac | 916 | * "timeout". adns_errtypeabbrev returns the abbreviation of the |
917 | * error class: ie, for values up to adns_s_max_XXX it will return the | |
918 | * string XXX. You MUST NOT call these functions with status values | |
74c94831 | 919 | * not returned by the same adns library. |
920 | */ | |
7f702335 | 921 | |
62049492 | 922 | #ifdef __cplusplus |
923 | } /* end of extern "C" */ | |
924 | #endif | |
5db99a2e | 925 | #endif |