5628df75 |
1 | /* |
18d49d56 |
2 | * adns.h |
3 | * - adns user-visible API (single-threaded, without any locking) |
4 | */ |
5 | /* |
d942707d |
6 | * |
7 | * This file is |
8 | * Copyright (C) 1997-1999 Ian Jackson <ian@davenant.greenend.org.uk> |
9 | * |
10 | * It is part of adns, which is |
11 | * Copyright (C) 1997-1999 Ian Jackson <ian@davenant.greenend.org.uk> |
12 | * Copyright (C) 1999 Tony Finch <dot@dotat.at> |
e576be50 |
13 | * |
14 | * This program is free software; you can redistribute it and/or modify |
15 | * it under the terms of the GNU General Public License as published by |
16 | * the Free Software Foundation; either version 2, or (at your option) |
17 | * any later version. |
18 | * |
19 | * This program is distributed in the hope that it will be useful, |
20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
22 | * GNU General Public License for more details. |
d942707d |
23 | * |
24 | * |
25 | * For the benefit of certain LGPL'd `omnibus' software which provides |
26 | * a uniform interface to various things including adns, I make the |
27 | * following additional licence. I do this because the GPL would |
28 | * otherwise force either the omnibus software to be GPL'd or for the |
29 | * adns-using part to be distributed separately. |
30 | * |
31 | * So, you may also redistribute and/or modify adns.h (but only the |
32 | * public header file adns.h and not any other part of adns) under the |
33 | * terms of the GNU Library General Public License as published by the |
34 | * Free Software Foundation; either version 2 of the License, or (at |
35 | * your option) any later version. |
e576be50 |
36 | * |
d942707d |
37 | * Note that adns itself is GPL'd. Authors of adns-using applications |
38 | * with GPL-incompatible licences, and people who distribute adns with |
39 | * applications where the whole distribution is not GPL'd, are still |
40 | * likely to be in violation of the GPL. Anyone who wants to do this |
41 | * should contact Ian Jackson. Please note that to avoid encouraging |
42 | * people to infringe the GPL as it applies the body of adns, I think |
43 | * that if you take advantage of the special exception to redistribute |
44 | * just adns.h under the LGPL, you should retain this paragraph in its |
45 | * place in the appropriate copyright statements. |
46 | * |
47 | * |
48 | * You should have received a copy of the GNU General Public License, |
49 | * or the GNU Library General Public License, as appropriate, along |
50 | * with this program; if not, write to the Free Software Foundation, |
a719a4be |
51 | * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
52 | * |
d942707d |
53 | * |
a719a4be |
54 | * $Id$ |
e576be50 |
55 | */ |
a17d3a1d |
56 | |
57 | #ifndef ADNS_H_INCLUDED |
58 | #define ADNS_H_INCLUDED |
02b47faa |
59 | #ifdef __cplusplus |
60 | extern "C" { /* I really dislike this - iwj. */ |
61 | #endif |
a17d3a1d |
62 | |
4353a5c4 |
63 | #include <stdio.h> |
64 | |
964344fc |
65 | #include <sys/socket.h> |
66 | #include <netinet/in.h> |
636b69b1 |
67 | #include <sys/types.h> |
68 | #include <sys/time.h> |
69 | #include <unistd.h> |
964344fc |
70 | |
09957b1c |
71 | /* All struct in_addr anywhere in adns are in NETWORK byte order. */ |
72 | |
964344fc |
73 | typedef struct adns__state *adns_state; |
74 | typedef struct adns__query *adns_query; |
a17d3a1d |
75 | |
76 | typedef enum { |
37e28fde |
77 | adns_if_noenv= 0x0001, /* do not look at environment */ |
78 | adns_if_noerrprint= 0x0002, /* never print output to stderr (_debug overrides) */ |
79 | adns_if_noserverwarn= 0x0004, /* do not warn to stderr about duff nameservers etc */ |
ddfda861 |
80 | adns_if_debug= 0x0008, /* enable all output to stderr plus debug msgs */ |
37e28fde |
81 | adns_if_noautosys= 0x0010, /* do not make syscalls at every opportunity */ |
88372443 |
82 | adns_if_eintr= 0x0020, /* allow _wait and _synchronous to return EINTR */ |
ac868fa8 |
83 | adns_if_nosigpipe= 0x0040, /* applic has SIGPIPE set to SIG_IGN, do not protect */ |
3e2e5fab |
84 | adns_if_checkc_entex= 0x0100, /* do consistency checks on entry/exit to adns funcs */ |
0aa7cba0 |
85 | adns_if_checkc_freq= 0x0300 /* do consistency checks very frequently (slow!) */ |
a17d3a1d |
86 | } adns_initflags; |
87 | |
88 | typedef enum { |
b365d68a |
89 | adns_qf_search= 0x00000001, /* use the searchlist */ |
90 | adns_qf_usevc= 0x00000002, /* use a virtual circuit (TCP connection) */ |
91 | adns_qf_owner= 0x00000004, /* fill in the owner field in the answer */ |
92 | adns_qf_quoteok_query= 0x00000010, /* allow quote-requiring chars in query domain */ |
93 | adns_qf_quoteok_cname= 0x00000000, /* allow ... in CNAME we go via - now default */ |
94 | adns_qf_quoteok_anshost= 0x00000040, /* allow ... in things supposed to be hostnames */ |
95 | adns_qf_quotefail_cname= 0x00000080, /* refuse if quote-req chars in CNAME we go via */ |
96 | adns_qf_cname_loose= 0x00000100, /* allow refs to CNAMEs - without, get _s_cname */ |
97 | adns_qf_cname_forbid= 0x00000200, /* don't follow CNAMEs, instead give _s_cname */ |
98 | adns__qf_internalmask= 0x0ff00000 |
a17d3a1d |
99 | } adns_queryflags; |
100 | |
101 | typedef enum { |
350d37d9 |
102 | adns__rrt_typemask= 0x0ffff, |
ddfda861 |
103 | adns__qtf_deref= 0x10000, /* dereference domains and perhaps produce extra data */ |
104 | adns__qtf_mail822= 0x20000, /* make mailboxes be in RFC822 rcpt field format */ |
ddfda861 |
105 | |
350d37d9 |
106 | adns_r_none= 0, |
ddfda861 |
107 | |
350d37d9 |
108 | adns_r_a= 1, |
ddfda861 |
109 | |
350d37d9 |
110 | adns_r_ns_raw= 2, |
111 | adns_r_ns= adns_r_ns_raw|adns__qtf_deref, |
ddfda861 |
112 | |
350d37d9 |
113 | adns_r_cname= 5, |
ddfda861 |
114 | |
350d37d9 |
115 | adns_r_soa_raw= 6, |
ddfda861 |
116 | adns_r_soa= adns_r_soa_raw|adns__qtf_mail822, |
ddfda861 |
117 | |
350d37d9 |
118 | adns_r_ptr_raw= 12, |
119 | adns_r_ptr= adns_r_ptr_raw|adns__qtf_deref, |
ddfda861 |
120 | |
350d37d9 |
121 | adns_r_hinfo= 13, |
ddfda861 |
122 | |
350d37d9 |
123 | adns_r_mx_raw= 15, |
124 | adns_r_mx= adns_r_mx_raw|adns__qtf_deref, |
ddfda861 |
125 | |
350d37d9 |
126 | adns_r_txt= 16, |
ddfda861 |
127 | |
350d37d9 |
128 | adns_r_rp_raw= 17, |
4353a5c4 |
129 | adns_r_rp= adns_r_rp_raw|adns__qtf_mail822, |
828d89bd |
130 | |
131 | adns_r_addr= adns_r_a|adns__qtf_deref |
ddfda861 |
132 | |
a17d3a1d |
133 | } adns_rrtype; |
134 | |
b365d68a |
135 | /* |
136 | * In queries without qf_quoteok_*, all domains must have standard |
137 | * legal syntax, or you get adns_s_querydomainvalid (if the query |
138 | * domain contains bad characters) or adns_s_answerdomaininvalid (if |
139 | * the answer contains bad characters). |
140 | * |
141 | * In queries _with_ qf_quoteok_*, domains in the query or response |
142 | * may contain any characters, quoted according to RFC1035 5.1. On |
143 | * input to adns, the char* is a pointer to the interior of a " |
144 | * delimited string, except that " may appear in it, and on output, |
9da4a044 |
145 | * the char* is a pointer to a string which would be legal either |
146 | * inside or outside " delimiters, and any characters not usually |
147 | * legal in domain names will be quoted as \X (if the character is |
148 | * 33-126 except \ and ") or \DDD. |
964344fc |
149 | * |
b365d68a |
150 | * If the query goes via a CNAME then the canonical name (ie, the |
151 | * thing that the CNAME record refers to) is usually allowed to |
152 | * contain any characters, which will be quoted as above. With |
153 | * adns_qf_quotefail_cname you get adns_s_answerdomaininvalid when |
154 | * this happens. (This is a change from version 0.4 and earlier, in |
155 | * which failing the query was the default, and you had to say |
156 | * adns_qf_quoteok_cname to avoid this; that flag is now deprecated.) |
157 | * |
158 | * In version 0.4 and earlier, asking for _raw records containing |
159 | * mailboxes without specifying _qf_quoteok_anshost was silly. This |
160 | * is no longer the case. In this version only parts of responses |
161 | * that are actually supposed to be hostnames will be refused by |
162 | * default if quote-requiring characters are found. |
163 | */ |
164 | |
165 | /* |
166 | * If you ask for an RR which contains domains which are actually |
167 | * encoded mailboxes, and don't ask for the _raw version, then adns |
168 | * returns the mailbox formatted suitably for an RFC822 recipient |
169 | * header field. The particular format used is that if the mailbox |
170 | * requires quoting according to the rules in RFC822 then the |
171 | * local-part is quoted in double quotes, which end at the next |
172 | * unescaped double quote. (\ is the escape char, and is doubled, and |
173 | * is used to escape only \ and ".) Otherwise the local-part is |
174 | * presented as-is. In any case this is followed by an @ and the |
175 | * domain. The domain will not contain any characters not legal in |
176 | * hostnames. adns will protect the application from local parts |
177 | * containing control characters - these appear to be legal according |
178 | * to RFC822 but are clearly a bad idea. |
179 | * |
180 | * If you ask for the domain with _raw then _no_ checking is done |
181 | * (even on the host part, regardless of adns_qf_quoteok_anshost), and |
182 | * you just get the domain name in master file format. |
183 | * |
184 | * If no mailbox is supplied the returned string will be `.' in either |
185 | * caswe. |
964344fc |
186 | */ |
187 | |
a17d3a1d |
188 | typedef enum { |
189 | adns_s_ok, |
ea1e31e3 |
190 | |
191 | /* locally induced errors */ |
192 | adns_s_nomemory, |
193 | adns_s_unknownrrtype, |
620c146d |
194 | adns_s_systemfail, |
195 | |
196 | adns_s_max_localfail= 29, |
ea1e31e3 |
197 | |
198 | /* remotely induced errors, detected locally */ |
37e28fde |
199 | adns_s_timeout, |
4bec51a4 |
200 | adns_s_allservfail, |
ec477b9e |
201 | adns_s_norecurse, |
ea1e31e3 |
202 | adns_s_invalidresponse, |
203 | adns_s_unknownformat, |
620c146d |
204 | |
205 | adns_s_max_remotefail= 59, |
ea1e31e3 |
206 | |
207 | /* remotely induced errors, reported by remote server to us */ |
208 | adns_s_rcodeservfail, |
209 | adns_s_rcodeformaterror, |
210 | adns_s_rcodenotimplemented, |
211 | adns_s_rcoderefused, |
212 | adns_s_rcodeunknown, |
620c146d |
213 | |
b9de380c |
214 | adns_s_max_tempfail= 99, |
ea1e31e3 |
215 | |
216 | /* remote configuration errors */ |
217 | adns_s_inconsistent, /* PTR gives domain whose A does not exist and match */ |
218 | adns_s_prohibitedcname, /* CNAME found where eg A expected (not if _qf_loosecname) */ |
219 | adns_s_answerdomaininvalid, |
220 | adns_s_answerdomaintoolong, |
221 | adns_s_invaliddata, |
222 | |
223 | adns_s_max_misconfig= 199, |
224 | |
ea1e31e3 |
225 | /* permanent problems with the query */ |
226 | adns_s_querydomainwrong, |
227 | adns_s_querydomaininvalid, |
228 | adns_s_querydomaintoolong, |
229 | |
230 | adns_s_max_misquery= 299, |
231 | |
232 | /* permanent errors */ |
a17d3a1d |
233 | adns_s_nxdomain, |
0aa7cba0 |
234 | adns_s_nodata |
ea1e31e3 |
235 | |
a17d3a1d |
236 | } adns_status; |
237 | |
e8c505a5 |
238 | typedef struct { |
828d89bd |
239 | int len; |
240 | union { |
241 | struct sockaddr sa; |
242 | struct sockaddr_in inet; |
243 | } addr; |
551ff40f |
244 | } adns_rr_addr; |
828d89bd |
245 | |
246 | typedef struct { |
1dfe95d8 |
247 | char *host; |
84fe28db |
248 | adns_status astatus; |
249 | int naddrs; /* temp fail => -1, perm fail => 0, s_ok => >0 */ |
551ff40f |
250 | adns_rr_addr *addrs; |
c7836bc9 |
251 | } adns_rr_hostaddr; |
4353a5c4 |
252 | |
253 | typedef struct { |
9ec44266 |
254 | char *(array[2]); |
4353a5c4 |
255 | } adns_rr_strpair; |
256 | |
257 | typedef struct { |
258 | int i; |
1dfe95d8 |
259 | adns_rr_hostaddr ha; |
c7836bc9 |
260 | } adns_rr_inthostaddr; |
4353a5c4 |
261 | |
262 | typedef struct { |
e062dcae |
263 | /* Used both for mx_raw, in which case i is the preference and str the domain, |
264 | * and for txt, in which case each entry has i for the `text' length, |
265 | * and str for the data (which will have had an extra nul appended |
266 | * so that if it was plain text it is now a null-terminated string). |
267 | */ |
4353a5c4 |
268 | int i; |
269 | char *str; |
270 | } adns_rr_intstr; |
271 | |
272 | typedef struct { |
9ec44266 |
273 | adns_rr_intstr array[2]; |
274 | } adns_rr_intstrpair; |
275 | |
276 | typedef struct { |
277 | char *mname, *rname; |
4353a5c4 |
278 | unsigned long serial, refresh, retry, expire, minimum; |
279 | } adns_rr_soa; |
84fe28db |
280 | |
281 | typedef struct { |
a17d3a1d |
282 | adns_status status; |
283 | char *cname; /* always NULL if query was for CNAME records */ |
22181a31 |
284 | char *owner; /* only set if requested in query flags */ |
86e7b8d9 |
285 | adns_rrtype type; /* guaranteed to be same as in query */ |
73dba56e |
286 | time_t expires; /* expiry time, defined only if _s_ok, nxdomain or nodata. NOT TTL! */ |
b365d68a |
287 | int nrrs, rrsz; /* nrrs is 0 if an error occurs */ |
a17d3a1d |
288 | union { |
8e5b0abb |
289 | void *untyped; |
290 | unsigned char *bytes; |
c7836bc9 |
291 | char *(*str); /* ns_raw, cname, ptr, ptr_raw */ |
292 | adns_rr_intstr *(*manyistr); /* txt (list of strings ends with i=-1, str=0) */ |
551ff40f |
293 | adns_rr_addr *addr; /* addr */ |
c7836bc9 |
294 | struct in_addr *inaddr; /* a */ |
295 | adns_rr_hostaddr *hostaddr; /* ns */ |
9ec44266 |
296 | adns_rr_intstrpair *intstrpair; /* hinfo */ |
297 | adns_rr_strpair *strpair; /* rp, rp_raw */ |
c7836bc9 |
298 | adns_rr_inthostaddr *inthostaddr; /* mx */ |
299 | adns_rr_intstr *intstr; /* mx_raw */ |
300 | adns_rr_soa *soa; /* soa, soa_raw */ |
a17d3a1d |
301 | } rrs; |
e8c505a5 |
302 | } adns_answer; |
a17d3a1d |
303 | |
304 | /* Memory management: |
305 | * adns_state and adns_query are actually pointers to malloc'd state; |
306 | * On submission questions are copied, including the owner domain; |
4353a5c4 |
307 | * Answers are malloc'd as a single piece of memory; pointers in the |
308 | * answer struct point into further memory in the answer. |
a17d3a1d |
309 | * query_io: |
310 | * Must always be non-null pointer; |
311 | * If *query_io is 0 to start with then any query may be returned; |
312 | * If *query_io is !0 adns_query then only that query may be returned. |
d3eea642 |
313 | * If the call is successful, *query_io, *answer_r, and *context_r |
314 | * will all be set. |
a17d3a1d |
315 | * Errors: |
620c146d |
316 | * Return values are 0 or an errno value. |
317 | * |
318 | * For _init, _init_strcfg, _submit and _synchronous, system errors |
319 | * (eg, failure to create sockets, malloc failure, etc.) return errno |
320 | * values. |
321 | * |
322 | * For _wait and _check failures are reported in the answer |
323 | * structure, and only 0, ESRCH or (for _check) EWOULDBLOCK is |
324 | * returned: if no (appropriate) requests are done adns_check returns |
325 | * EWOULDBLOCK; if no (appropriate) requests are outstanding both |
326 | * adns_query and adns_wait return ESRCH. |
327 | * |
328 | * Additionally, _wait can return EINTR if you set adns_if_eintr. |
329 | * |
330 | * All other errors (nameserver failure, timed out connections, &c) |
331 | * are returned in the status field of the answer. After a |
332 | * successful _wait or _check, if status is nonzero then nrrs will be |
333 | * 0, otherwise it will be >0. type will always be the type |
334 | * requested. |
a17d3a1d |
335 | */ |
336 | |
36369543 |
337 | int adns_init(adns_state *newstate_r, adns_initflags flags, |
338 | FILE *diagfile /*0=>stderr*/); |
339 | |
340 | int adns_init_strcfg(adns_state *newstate_r, adns_initflags flags, |
341 | FILE *diagfile /*0=>discard*/, const char *configtext); |
c8c7c813 |
342 | |
343 | /* Configuration: |
344 | * adns_init reads /etc/resolv.conf, which is expected to be (broadly |
345 | * speaking) in the format expected by libresolv. adns_init_strcfg |
346 | * is instead passed a string which is interpreted as if it were the |
347 | * contents of resolv.conf. In general, configuration which is set |
348 | * later overrides any that is set earlier. |
349 | * |
350 | * Standard directives understood in resolv.conf: |
351 | * |
352 | * nameserver <address> |
353 | * Must be followed by the IP address of a nameserver. Several |
354 | * nameservers may be specified, and they will be tried in the order |
355 | * found. There is a compiled in limit, currently 5, on the number |
356 | * of nameservers. (libresolv supports only 3 nameservers.) |
357 | * |
358 | * search <domain> ... |
359 | * Specifies the search list for queries which specify |
360 | * adns_qf_search. This is a list of domains to append to the query |
361 | * domain. The query domain will be tried as-is either before all |
362 | * of these or after them, depending on the ndots option setting |
363 | * (see below). |
364 | * |
365 | * domain <domain> |
366 | * This is present only for backward compatibility with obsolete |
367 | * versions of libresolv. It should not be used, and is interpreted |
368 | * by adns as if it were `search' - note that this is subtly |
369 | * different to libresolv's interpretation of this directive. |
370 | * |
371 | * sortlist <addr>/<mask> ... |
372 | * Should be followed by a sequence of IP-address and netmask pairs, |
373 | * separated by spaces. They may be specified as |
374 | * eg. 172.30.206.0/24 or 172.30.206.0/255.255.255.0. Currently up |
375 | * to 15 pairs may be specified (but note that libresolv only |
376 | * supports up to 10). |
377 | * |
378 | * options |
379 | * Should followed by one or more options, separated by spaces. |
380 | * Each option consists of an option name, followed by optionally |
381 | * a colon and a value. Options are listed below. |
382 | * |
383 | * Non-standard directives understood in resolv.conf: |
384 | * |
385 | * clearnameservers |
386 | * Clears the list of nameservers, so that further nameserver lines |
387 | * start again from the beginning. |
388 | * |
389 | * include <filename> |
390 | * The specified file will be read. |
391 | * |
392 | * Additionally, adns will ignore lines in resolv.conf which start with a #. |
393 | * |
394 | * Standard options understood: |
395 | * |
396 | * debug |
397 | * Enables debugging output from the resolver, which will be written |
398 | * to stderr. |
399 | * |
400 | * ndots:<count> |
401 | * Affects whether queries with adns_qf_search will be tried first |
402 | * without adding domains from the searchlist, or whether the bare |
403 | * query domain will be tried last. Queries which contain at least |
404 | * <count> dots will be tried bare first. The default is 1. |
405 | * |
406 | * Non-standard options understood: |
407 | * |
408 | * adns_checkc:none |
409 | * adns_checkc:entex |
410 | * adns_checkc:freq |
411 | * Changes the consistency checking frequency; this overrides the |
412 | * setting of adns_if_check_entex, adns_if_check_freq, or neither, |
413 | * in the flags passed to adns_init. |
414 | * |
415 | * There are a number of environment variables which can modify the |
416 | * behaviour of adns. They take effect only if adns_init is used, and |
417 | * the caller of adns_init can disable them using adns_if_noenv. In |
418 | * each case there is both a FOO and an ADNS_FOO; the latter is |
419 | * interpreted later so that it can override the former. Unless |
420 | * otherwise stated, environment variables are interpreted after |
421 | * resolv.conf is read, in the order they are listed here. |
422 | * |
423 | * RES_CONF, ADNS_RES_CONF |
424 | * A filename, whose contets are in the format of resolv.conf. |
425 | * |
426 | * RES_CONF_TEXT, ADNS_RES_CONF_TEXT |
427 | * A string in the format of resolv.conf. |
428 | * |
429 | * RES_OPTIONS, ADNS_RES_OPTIONS |
430 | * These are parsed as if they appeared in the `options' line of a |
431 | * resolv.conf. In addition to being parsed at this point in the |
432 | * sequence, they are also parsed at the very beginning before |
433 | * resolv.conf or any other environment variables are read, so that |
434 | * any debug option can affect the processing of the configuration. |
435 | * |
436 | * LOCALDOMAIN, ADNS_LOCALDOMAIN |
437 | * These are interpreted as if their contents appeared in a `search' |
438 | * line in resolv.conf. |
439 | */ |
a17d3a1d |
440 | |
441 | int adns_synchronous(adns_state ads, |
442 | const char *owner, |
443 | adns_rrtype type, |
72934832 |
444 | adns_queryflags flags, |
9d95094c |
445 | adns_answer **answer_r); |
e8c505a5 |
446 | |
447 | /* NB: if you set adns_if_noautosys then _submit and _check do not |
620c146d |
448 | * make any system calls; you must use some of the asynch-io event |
449 | * processing functions to actually get things to happen. |
e8c505a5 |
450 | */ |
a17d3a1d |
451 | |
452 | int adns_submit(adns_state ads, |
453 | const char *owner, |
454 | adns_rrtype type, |
72934832 |
455 | adns_queryflags flags, |
a17d3a1d |
456 | void *context, |
964344fc |
457 | adns_query *query_r); |
a17d3a1d |
458 | |
964344fc |
459 | int adns_check(adns_state ads, |
a17d3a1d |
460 | adns_query *query_io, |
9d95094c |
461 | adns_answer **answer_r, |
462 | void **context_r); |
a17d3a1d |
463 | |
464 | int adns_wait(adns_state ads, |
465 | adns_query *query_io, |
9d95094c |
466 | adns_answer **answer_r, |
467 | void **context_r); |
a17d3a1d |
468 | |
940356bd |
469 | /* same as adns_wait but uses poll(2) internally */ |
470 | int adns_wait_poll(adns_state ads, |
471 | adns_query *query_io, |
472 | adns_answer **answer_r, |
473 | void **context_r); |
474 | |
3955725c |
475 | void adns_cancel(adns_query query); |
a17d3a1d |
476 | |
620c146d |
477 | /* The adns_query you get back from _submit is valid (ie, can be |
478 | * legitimately passed into adns functions) until it is returned by |
479 | * adns_check or adns_wait, or passed to adns_cancel. After that it |
480 | * must not be used. You can rely on it not being reused until the |
481 | * first adns_submit or _transact call using the same adns_state after |
482 | * it became invalid, so you may compare it for equality with other |
483 | * query handles until you next call _query or _transact. |
636b69b1 |
484 | * |
485 | * _submit and _synchronous return ENOSYS if they don't understand the |
486 | * query type. |
e576be50 |
487 | */ |
a17d3a1d |
488 | |
b365d68a |
489 | int adns_submit_reverse(adns_state ads, |
490 | const struct sockaddr *addr, |
491 | adns_rrtype type, |
492 | adns_queryflags flags, |
493 | void *context, |
494 | adns_query *query_r); |
495 | /* type must be _r_ptr or _r_ptr_raw. _qf_search is ignored. */ |
496 | |
620c146d |
497 | void adns_finish(adns_state ads); |
e576be50 |
498 | /* You may call this even if you have queries outstanding; |
499 | * they will be cancelled. |
500 | */ |
a17d3a1d |
501 | |
964344fc |
502 | |
958ad1f0 |
503 | void adns_forallqueries_begin(adns_state ads); |
8ce38e76 |
504 | adns_query adns_forallqueries_next(adns_state ads, void **context_r); |
620c146d |
505 | /* Iterator functions, which you can use to loop over the outstanding |
958ad1f0 |
506 | * (submitted but not yet successfuly checked/waited) queries. |
a8768e80 |
507 | * |
958ad1f0 |
508 | * You can only have one iteration going at once. You may call _begin |
509 | * at any time; after that, an iteration will be in progress. You may |
510 | * only call _next when an iteration is in progress - anything else |
511 | * may coredump. The iteration remains in progress until _next |
512 | * returns 0, indicating that all the queries have been walked over, |
513 | * or ANY other adns function is called with the same adns_state (or a |
514 | * query in the same adns_state). There is no need to explicitly |
515 | * finish an iteration. |
516 | * |
8ce38e76 |
517 | * context_r may be 0. *context_r may not be set when _next returns 0. |
964344fc |
518 | */ |
a17d3a1d |
519 | |
28de6442 |
520 | void adns_checkconsistency(adns_state ads, adns_query qu); |
3e2e5fab |
521 | /* Checks the consistency of adns's internal data structures. |
522 | * If any error is found, the program will abort(). |
28de6442 |
523 | * You may pass 0 for qu; if you pass non-null then additional checks |
524 | * are done to make sure that qu is a valid query. |
3e2e5fab |
525 | */ |
526 | |
620c146d |
527 | /* |
528 | * Example expected/legal calling sequence for submit/check/wait: |
a17d3a1d |
529 | * adns_init |
530 | * adns_submit 1 |
531 | * adns_submit 2 |
532 | * adns_submit 3 |
533 | * adns_wait 1 |
964344fc |
534 | * adns_check 3 -> EWOULDBLOCK |
a17d3a1d |
535 | * adns_wait 2 |
536 | * adns_wait 3 |
537 | * .... |
538 | * adns_finish |
620c146d |
539 | */ |
540 | |
541 | /* |
542 | * Entrypoints for generic asynch io: |
543 | * (these entrypoints are not very useful except in combination with * |
544 | * some of the other I/O model calls which can tell you which fds to |
545 | * be interested in): |
546 | * |
547 | * Note that any adns call may cause adns to open and close fds, so |
548 | * you must call beforeselect or beforepoll again just before |
549 | * blocking, or you may not have an up-to-date list of it's fds. |
550 | */ |
551 | |
552 | int adns_processany(adns_state ads); |
553 | /* Gives adns flow-of-control for a bit. This will never block, and |
554 | * can be used with any threading/asynch-io model. If some error |
555 | * occurred which might cause an event loop to spin then the errno |
556 | * value is returned. |
557 | */ |
558 | |
559 | int adns_processreadable(adns_state ads, int fd, const struct timeval *now); |
560 | int adns_processwriteable(adns_state ads, int fd, const struct timeval *now); |
561 | int adns_processexceptional(adns_state ads, int fd, const struct timeval *now); |
562 | /* Gives adns flow-of-control so that it can process incoming data |
563 | * from, or send outgoing data via, fd. Very like _processany. If it |
564 | * returns zero then fd will no longer be readable or writeable |
565 | * (unless of course more data has arrived since). adns will _only_ |
0a106d94 |
566 | * use that fd and only in the manner specified, regardless of whether |
620c146d |
567 | * adns_if_noautosys was specified. |
568 | * |
569 | * adns_processexceptional should be called when select(2) reports an |
570 | * exceptional condition, or poll(2) reports POLLPRI. |
571 | * |
572 | * It is fine to call _processreabable or _processwriteable when the |
573 | * fd is not ready, or with an fd that doesn't belong to adns; it will |
574 | * then just return 0. |
575 | * |
576 | * If some error occurred which might prevent an event loop to spin |
577 | * then the errno value is returned. |
578 | */ |
579 | |
580 | void adns_processtimeouts(adns_state ads, const struct timeval *now); |
581 | /* Gives adns flow-of-control so that it can process any timeouts |
582 | * which might have happened. Very like _processreadable/writeable. |
583 | * |
584 | * now may be 0; if it isn't, *now must be the current time, recently |
585 | * obtained from gettimeofday. |
586 | */ |
587 | |
588 | void adns_firsttimeout(adns_state ads, |
589 | struct timeval **tv_mod, struct timeval *tv_buf, |
590 | struct timeval now); |
591 | /* Asks adns when it would first like the opportunity to time |
592 | * something out. now must be the current time, from gettimeofday. |
593 | * |
594 | * If tv_mod points to 0 then tv_buf must be non-null, and |
595 | * _firsttimeout will fill in *tv_buf with the time until the first |
596 | * timeout, and make *tv_mod point to tv_buf. If adns doesn't have |
597 | * anything that might need timing out it will leave *tv_mod as 0. |
598 | * |
599 | * If *tv_mod is not 0 then tv_buf is not used. adns will update |
600 | * *tv_mod if it has any earlier timeout, and leave it alone if it |
601 | * doesn't. |
602 | * |
603 | * This call will not actually do any I/O, or change the fds that adns |
604 | * is using. It always succeeds and never blocks. |
605 | */ |
606 | |
607 | void adns_globalsystemfailure(adns_state ads); |
608 | /* If serious problem(s) happen which globally affect your ability to |
609 | * interact properly with adns, or adns's ability to function |
610 | * properly, you or adns can call this function. |
611 | * |
612 | * All currently outstanding queries will be made to fail with |
613 | * adns_s_systemfail, and adns will close any stream sockets it has |
614 | * open. |
615 | * |
616 | * This is used by adns, for example, if gettimeofday() fails. |
617 | * Without this the program's event loop might start to spin ! |
618 | * |
619 | * This call will never block. |
620 | */ |
621 | |
622 | /* |
623 | * Entrypoints for select-loop based asynch io: |
624 | */ |
625 | |
626 | void adns_beforeselect(adns_state ads, int *maxfd, fd_set *readfds, |
627 | fd_set *writefds, fd_set *exceptfds, |
628 | struct timeval **tv_mod, struct timeval *tv_buf, |
629 | const struct timeval *now); |
630 | /* Find out file descriptors adns is interested in, and when it would |
631 | * like the opportunity to time something out. If you do not plan to |
632 | * block then tv_mod may be 0. Otherwise, tv_mod and tv_buf are as |
633 | * for adns_firsttimeout. readfds, writefds, exceptfds and maxfd_io may |
634 | * not be 0. |
635 | * |
636 | * If *now is not 0 then this will never actually do any I/O, or |
637 | * change the fds that adns is using or the timeouts it wants. In any |
638 | * case it won't block. |
639 | */ |
640 | |
641 | void adns_afterselect(adns_state ads, int maxfd, const fd_set *readfds, |
642 | const fd_set *writefds, const fd_set *exceptfds, |
643 | const struct timeval *now); |
644 | /* Gives adns flow-of-control for a bit; intended for use after |
645 | * select. This is just a fancy way of calling adns_processreadable/ |
646 | * writeable/timeouts as appropriate, as if select had returned the |
647 | * data being passed. Always succeeds. |
648 | */ |
649 | |
650 | /* |
651 | * Example calling sequence: |
a17d3a1d |
652 | * |
e8c505a5 |
653 | * adns_init _noautosys |
a17d3a1d |
654 | * loop { |
620c146d |
655 | * adns_beforeselect |
a17d3a1d |
656 | * select |
620c146d |
657 | * adns_afterselect |
e8c505a5 |
658 | * ... |
659 | * adns_submit / adns_check |
660 | * ... |
a17d3a1d |
661 | * } |
662 | */ |
663 | |
620c146d |
664 | /* |
665 | * Entrypoints for poll-loop based asynch io: |
666 | */ |
667 | |
668 | struct pollfd; |
669 | /* In case your system doesn't have it or you forgot to include |
670 | * <sys/poll.h>, to stop the following declarations from causing |
671 | * problems. If your system doesn't have poll then the following |
672 | * entrypoints will not be defined in libadns. Sorry ! |
673 | */ |
674 | |
675 | int adns_beforepoll(adns_state ads, struct pollfd *fds, int *nfds_io, int *timeout_io, |
676 | const struct timeval *now); |
677 | /* Finds out which fd's adns is interested in, and when it would like |
678 | * to be able to time things out. This is in a form suitable for use |
679 | * with poll(2). |
680 | * |
681 | * On entry, usually fds should point to at least *nfds_io structs. |
682 | * adns will fill up to that many structs will information for poll, |
683 | * and record in *nfds_io how many structs it filled. If it wants to |
684 | * listen for more structs then *nfds_io will be set to the number |
685 | * required and _beforepoll will return ERANGE. |
686 | * |
620c146d |
687 | * You may call _beforepoll with fds==0 and *nfds_io 0, in which case |
688 | * adns will fill in the number of fds that it might be interested in |
fc6a52ae |
689 | * in *nfds_io, and always return either 0 (if it is not interested in |
690 | * any fds) or ERANGE (if it is). |
691 | * |
c912639e |
692 | * NOTE that (unless now is 0) adns may acquire additional fds |
fc6a52ae |
693 | * from one call to the next, so you must put adns_beforepoll in a |
694 | * loop, rather than assuming that the second call (with the buffer |
695 | * size requested by the first) will not return ERANGE. |
620c146d |
696 | * |
697 | * adns only ever sets POLLIN, POLLOUT and POLLPRI in its pollfd |
698 | * structs, and only ever looks at those bits. POLLPRI is required to |
fc6a52ae |
699 | * detect TCP Urgent Data (which should not be used by a DNS server) |
620c146d |
700 | * so that adns can know that the TCP stream is now useless. |
701 | * |
702 | * In any case, *timeout_io should be a timeout value as for poll(2), |
703 | * which adns will modify downwards as required. If the caller does |
fc6a52ae |
704 | * not plan to block then *timeout_io should be 0 on entry, or |
705 | * alternatively, timeout_io may be 0. (Alternatively, the caller may |
706 | * use _beforeselect with timeout_io==0 to find out about file |
707 | * descriptors, and use _firsttimeout is used to find out when adns |
708 | * might want to time something out.) |
620c146d |
709 | * |
710 | * adns_beforepoll will return 0 on success, and will not fail for any |
711 | * reason other than the fds buffer being too small (ERANGE). |
712 | * |
c912639e |
713 | * This call will never actually do any I/O. If you supply the |
714 | * current time it will not change the fds that adns is using or the |
715 | * timeouts it wants. |
716 | * |
717 | * In any case this call won't block. |
620c146d |
718 | */ |
719 | |
720 | #define ADNS_POLLFDS_RECOMMENDED 2 |
721 | /* If you allocate an fds buf with at least RECOMMENDED entries then |
722 | * you are unlikely to need to enlarge it. You are recommended to do |
723 | * so if it's convenient. However, you must be prepared for adns to |
724 | * require more space than this. |
725 | */ |
726 | |
727 | void adns_afterpoll(adns_state ads, const struct pollfd *fds, int nfds, |
728 | const struct timeval *now); |
729 | /* Gives adns flow-of-control for a bit; intended for use after |
730 | * poll(2). fds and nfds should be the results from poll(). pollfd |
731 | * structs mentioning fds not belonging to adns will be ignored. |
732 | */ |
733 | |
734 | |
86e7b8d9 |
735 | adns_status adns_rr_info(adns_rrtype type, |
736 | const char **rrtname_r, const char **fmtname_r, |
737 | int *len_r, |
738 | const void *datap, char **data_r); |
b365d68a |
739 | /* |
740 | |
741 | * Get information about a query type, or convert reply data to a |
742 | * textual form. type must be specified, and the official name of the |
743 | * corresponding RR type will be returned in *rrtname_r, and |
744 | * information about the processing style in *fmtname_r. The length |
745 | * of the table entry in an answer for that type will be returned in |
746 | * in *len_r. Any or all of rrtname_r, fmtname_r and len_r may be 0. |
747 | * If fmtname_r is non-null then *fmtname_r may be null on return, |
748 | * indicating that no special processing is involved. |
749 | * |
750 | * data_r be must be non-null iff datap is. In this case *data_r will |
751 | * be set to point to a string pointing to a representation of the RR |
752 | * data in master file format. (The owner name, timeout, class and |
753 | * type will not be present - only the data part of the RR.) The |
754 | * memory will have been obtained from malloc() and must be freed by |
755 | * the caller. |
86e7b8d9 |
756 | * |
757 | * Usually this routine will succeed. Possible errors include: |
758 | * adns_s_nomemory |
ea1e31e3 |
759 | * adns_s_rrtypeunknown |
86e7b8d9 |
760 | * adns_s_invaliddata (*datap contained garbage) |
761 | * If an error occurs then no memory has been allocated, |
762 | * and *rrtname_r, *fmtname_r, *len_r and *data_r are undefined. |
b365d68a |
763 | * |
764 | * There are some adns-invented data formats which are not official |
765 | * master file formats. These include: |
766 | * |
767 | * Mailboxes if __qtf_mail822: these are just included as-is. |
768 | * |
769 | * Addresses (adns_rr_addr): these may be of pretty much any type. |
770 | * The representation is in two parts: first, a word for the address |
771 | * family (ie, in AF_XXX, the XXX), and then one or more items for the |
772 | * address itself, depending on the format. For an IPv4 address the |
773 | * syntax is INET followed by the dotted quad (from inet_ntoa). |
774 | * Currently only IPv4 is supported. |
775 | * |
a6f1dc92 |
776 | * Text strings (as in adns_rr_txt) appear inside double quotes, and |
777 | * use \" and \\ to represent " and \, and \xHH to represent |
778 | * characters not in the range 32-126. |
779 | * |
b365d68a |
780 | * Hostname with addresses (adns_rr_hostaddr): this consists of the |
a6f1dc92 |
781 | * hostname, as usual, followed by the adns_status value, as an |
782 | * abbreviation, and then a descriptive string (encoded as if it were |
783 | * a piece of text), for the address lookup, followed by zero or more |
b365d68a |
784 | * addresses enclosed in ( and ). If the result was a permanent |
785 | * failure, then a single ? appears instead of the ( ). If the |
786 | * result was a temporary failure then an empty pair of parentheses |
787 | * appears (which a space in between). For example, one of the NS |
a6f1dc92 |
788 | * records for greenend.org.uk comes out like |
789 | * ns.chiark.greenend.org.uk ok "OK" ( INET 195.224.76.132 ) |
b365d68a |
790 | * an MX referring to a nonexistent host might come out like: |
a6f1dc92 |
791 | * 50 sun2.nsfnet-relay.ac.uk nxdomain "No such domain" ( ) |
b365d68a |
792 | * and if nameserver information is not available you might get: |
a6f1dc92 |
793 | * dns2.spong.dyn.ml.org timeout "DNS query timed out" ? |
86e7b8d9 |
794 | */ |
795 | |
31144a72 |
796 | const char *adns_strerror(adns_status st); |
9da4a044 |
797 | const char *adns_errabbrev(adns_status st); |
620c146d |
798 | /* Like strerror but for adns_status values. adns_errabbrev returns |
799 | * the abbreviation of the error - eg, for adns_s_timeout it returns |
800 | * "timeout". You MUST NOT call these functions with status values |
801 | * not returned by the same adns library. |
802 | */ |
31144a72 |
803 | |
02b47faa |
804 | #ifdef __cplusplus |
805 | } /* end of extern "C" */ |
806 | #endif |
a17d3a1d |
807 | #endif |