5628df75 |
1 | /* |
18d49d56 |
2 | * adns.h |
3 | * - adns user-visible API (single-threaded, without any locking) |
4 | */ |
5 | /* |
a719a4be |
6 | * This file is part of adns, which is Copyright (C) 1997-1999 Ian Jackson |
e576be50 |
7 | * |
8 | * This program is free software; you can redistribute it and/or modify |
9 | * it under the terms of the GNU General Public License as published by |
10 | * the Free Software Foundation; either version 2, or (at your option) |
11 | * any later version. |
12 | * |
13 | * This program is distributed in the hope that it will be useful, |
14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
16 | * GNU General Public License for more details. |
17 | * |
18 | * You should have received a copy of the GNU General Public License |
19 | * along with this program; if not, write to the Free Software Foundation, |
a719a4be |
20 | * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
21 | * |
22 | * $Id$ |
e576be50 |
23 | */ |
a17d3a1d |
24 | |
25 | #ifndef ADNS_H_INCLUDED |
26 | #define ADNS_H_INCLUDED |
02b47faa |
27 | #ifdef __cplusplus |
28 | extern "C" { /* I really dislike this - iwj. */ |
29 | #endif |
a17d3a1d |
30 | |
4353a5c4 |
31 | #include <stdio.h> |
32 | |
964344fc |
33 | #include <sys/socket.h> |
34 | #include <netinet/in.h> |
636b69b1 |
35 | #include <sys/types.h> |
36 | #include <sys/time.h> |
37 | #include <unistd.h> |
964344fc |
38 | |
09957b1c |
39 | /* All struct in_addr anywhere in adns are in NETWORK byte order. */ |
40 | |
964344fc |
41 | typedef struct adns__state *adns_state; |
42 | typedef struct adns__query *adns_query; |
a17d3a1d |
43 | |
44 | typedef enum { |
37e28fde |
45 | adns_if_noenv= 0x0001, /* do not look at environment */ |
46 | adns_if_noerrprint= 0x0002, /* never print output to stderr (_debug overrides) */ |
47 | adns_if_noserverwarn= 0x0004, /* do not warn to stderr about duff nameservers etc */ |
ddfda861 |
48 | adns_if_debug= 0x0008, /* enable all output to stderr plus debug msgs */ |
37e28fde |
49 | adns_if_noautosys= 0x0010, /* do not make syscalls at every opportunity */ |
88372443 |
50 | adns_if_eintr= 0x0020, /* allow _wait and _synchronous to return EINTR */ |
ac868fa8 |
51 | adns_if_nosigpipe= 0x0040, /* applic has SIGPIPE set to SIG_IGN, do not protect */ |
a17d3a1d |
52 | } adns_initflags; |
53 | |
54 | typedef enum { |
b365d68a |
55 | adns_qf_search= 0x00000001, /* use the searchlist */ |
56 | adns_qf_usevc= 0x00000002, /* use a virtual circuit (TCP connection) */ |
57 | adns_qf_owner= 0x00000004, /* fill in the owner field in the answer */ |
58 | adns_qf_quoteok_query= 0x00000010, /* allow quote-requiring chars in query domain */ |
59 | adns_qf_quoteok_cname= 0x00000000, /* allow ... in CNAME we go via - now default */ |
60 | adns_qf_quoteok_anshost= 0x00000040, /* allow ... in things supposed to be hostnames */ |
61 | adns_qf_quotefail_cname= 0x00000080, /* refuse if quote-req chars in CNAME we go via */ |
62 | adns_qf_cname_loose= 0x00000100, /* allow refs to CNAMEs - without, get _s_cname */ |
63 | adns_qf_cname_forbid= 0x00000200, /* don't follow CNAMEs, instead give _s_cname */ |
64 | adns__qf_internalmask= 0x0ff00000 |
a17d3a1d |
65 | } adns_queryflags; |
66 | |
67 | typedef enum { |
350d37d9 |
68 | adns__rrt_typemask= 0x0ffff, |
ddfda861 |
69 | adns__qtf_deref= 0x10000, /* dereference domains and perhaps produce extra data */ |
70 | adns__qtf_mail822= 0x20000, /* make mailboxes be in RFC822 rcpt field format */ |
ddfda861 |
71 | |
350d37d9 |
72 | adns_r_none= 0, |
ddfda861 |
73 | |
350d37d9 |
74 | adns_r_a= 1, |
ddfda861 |
75 | |
350d37d9 |
76 | adns_r_ns_raw= 2, |
77 | adns_r_ns= adns_r_ns_raw|adns__qtf_deref, |
ddfda861 |
78 | |
350d37d9 |
79 | adns_r_cname= 5, |
ddfda861 |
80 | |
350d37d9 |
81 | adns_r_soa_raw= 6, |
ddfda861 |
82 | adns_r_soa= adns_r_soa_raw|adns__qtf_mail822, |
ddfda861 |
83 | |
350d37d9 |
84 | adns_r_ptr_raw= 12, |
85 | adns_r_ptr= adns_r_ptr_raw|adns__qtf_deref, |
ddfda861 |
86 | |
350d37d9 |
87 | adns_r_hinfo= 13, |
ddfda861 |
88 | |
350d37d9 |
89 | adns_r_mx_raw= 15, |
90 | adns_r_mx= adns_r_mx_raw|adns__qtf_deref, |
ddfda861 |
91 | |
350d37d9 |
92 | adns_r_txt= 16, |
ddfda861 |
93 | |
350d37d9 |
94 | adns_r_rp_raw= 17, |
4353a5c4 |
95 | adns_r_rp= adns_r_rp_raw|adns__qtf_mail822, |
828d89bd |
96 | |
97 | adns_r_addr= adns_r_a|adns__qtf_deref |
ddfda861 |
98 | |
a17d3a1d |
99 | } adns_rrtype; |
100 | |
b365d68a |
101 | /* |
102 | * In queries without qf_quoteok_*, all domains must have standard |
103 | * legal syntax, or you get adns_s_querydomainvalid (if the query |
104 | * domain contains bad characters) or adns_s_answerdomaininvalid (if |
105 | * the answer contains bad characters). |
106 | * |
107 | * In queries _with_ qf_quoteok_*, domains in the query or response |
108 | * may contain any characters, quoted according to RFC1035 5.1. On |
109 | * input to adns, the char* is a pointer to the interior of a " |
110 | * delimited string, except that " may appear in it, and on output, |
9da4a044 |
111 | * the char* is a pointer to a string which would be legal either |
112 | * inside or outside " delimiters, and any characters not usually |
113 | * legal in domain names will be quoted as \X (if the character is |
114 | * 33-126 except \ and ") or \DDD. |
964344fc |
115 | * |
b365d68a |
116 | * If the query goes via a CNAME then the canonical name (ie, the |
117 | * thing that the CNAME record refers to) is usually allowed to |
118 | * contain any characters, which will be quoted as above. With |
119 | * adns_qf_quotefail_cname you get adns_s_answerdomaininvalid when |
120 | * this happens. (This is a change from version 0.4 and earlier, in |
121 | * which failing the query was the default, and you had to say |
122 | * adns_qf_quoteok_cname to avoid this; that flag is now deprecated.) |
123 | * |
124 | * In version 0.4 and earlier, asking for _raw records containing |
125 | * mailboxes without specifying _qf_quoteok_anshost was silly. This |
126 | * is no longer the case. In this version only parts of responses |
127 | * that are actually supposed to be hostnames will be refused by |
128 | * default if quote-requiring characters are found. |
129 | */ |
130 | |
131 | /* |
132 | * If you ask for an RR which contains domains which are actually |
133 | * encoded mailboxes, and don't ask for the _raw version, then adns |
134 | * returns the mailbox formatted suitably for an RFC822 recipient |
135 | * header field. The particular format used is that if the mailbox |
136 | * requires quoting according to the rules in RFC822 then the |
137 | * local-part is quoted in double quotes, which end at the next |
138 | * unescaped double quote. (\ is the escape char, and is doubled, and |
139 | * is used to escape only \ and ".) Otherwise the local-part is |
140 | * presented as-is. In any case this is followed by an @ and the |
141 | * domain. The domain will not contain any characters not legal in |
142 | * hostnames. adns will protect the application from local parts |
143 | * containing control characters - these appear to be legal according |
144 | * to RFC822 but are clearly a bad idea. |
145 | * |
146 | * If you ask for the domain with _raw then _no_ checking is done |
147 | * (even on the host part, regardless of adns_qf_quoteok_anshost), and |
148 | * you just get the domain name in master file format. |
149 | * |
150 | * If no mailbox is supplied the returned string will be `.' in either |
151 | * caswe. |
964344fc |
152 | */ |
153 | |
a17d3a1d |
154 | typedef enum { |
155 | adns_s_ok, |
ea1e31e3 |
156 | |
157 | /* locally induced errors */ |
158 | adns_s_nomemory, |
159 | adns_s_unknownrrtype, |
620c146d |
160 | adns_s_systemfail, |
161 | |
162 | adns_s_max_localfail= 29, |
ea1e31e3 |
163 | |
164 | /* remotely induced errors, detected locally */ |
37e28fde |
165 | adns_s_timeout, |
4bec51a4 |
166 | adns_s_allservfail, |
ec477b9e |
167 | adns_s_norecurse, |
ea1e31e3 |
168 | adns_s_invalidresponse, |
169 | adns_s_unknownformat, |
620c146d |
170 | |
171 | adns_s_max_remotefail= 59, |
ea1e31e3 |
172 | |
173 | /* remotely induced errors, reported by remote server to us */ |
174 | adns_s_rcodeservfail, |
175 | adns_s_rcodeformaterror, |
176 | adns_s_rcodenotimplemented, |
177 | adns_s_rcoderefused, |
178 | adns_s_rcodeunknown, |
620c146d |
179 | |
b9de380c |
180 | adns_s_max_tempfail= 99, |
ea1e31e3 |
181 | |
182 | /* remote configuration errors */ |
183 | adns_s_inconsistent, /* PTR gives domain whose A does not exist and match */ |
184 | adns_s_prohibitedcname, /* CNAME found where eg A expected (not if _qf_loosecname) */ |
185 | adns_s_answerdomaininvalid, |
186 | adns_s_answerdomaintoolong, |
187 | adns_s_invaliddata, |
188 | |
189 | adns_s_max_misconfig= 199, |
190 | |
ea1e31e3 |
191 | /* permanent problems with the query */ |
192 | adns_s_querydomainwrong, |
193 | adns_s_querydomaininvalid, |
194 | adns_s_querydomaintoolong, |
195 | |
196 | adns_s_max_misquery= 299, |
197 | |
198 | /* permanent errors */ |
a17d3a1d |
199 | adns_s_nxdomain, |
0ba0614a |
200 | adns_s_nodata, |
ea1e31e3 |
201 | |
a17d3a1d |
202 | } adns_status; |
203 | |
e8c505a5 |
204 | typedef struct { |
828d89bd |
205 | int len; |
206 | union { |
207 | struct sockaddr sa; |
208 | struct sockaddr_in inet; |
209 | } addr; |
551ff40f |
210 | } adns_rr_addr; |
828d89bd |
211 | |
212 | typedef struct { |
1dfe95d8 |
213 | char *host; |
84fe28db |
214 | adns_status astatus; |
215 | int naddrs; /* temp fail => -1, perm fail => 0, s_ok => >0 */ |
551ff40f |
216 | adns_rr_addr *addrs; |
c7836bc9 |
217 | } adns_rr_hostaddr; |
4353a5c4 |
218 | |
219 | typedef struct { |
9ec44266 |
220 | char *(array[2]); |
4353a5c4 |
221 | } adns_rr_strpair; |
222 | |
223 | typedef struct { |
224 | int i; |
1dfe95d8 |
225 | adns_rr_hostaddr ha; |
c7836bc9 |
226 | } adns_rr_inthostaddr; |
4353a5c4 |
227 | |
228 | typedef struct { |
e062dcae |
229 | /* Used both for mx_raw, in which case i is the preference and str the domain, |
230 | * and for txt, in which case each entry has i for the `text' length, |
231 | * and str for the data (which will have had an extra nul appended |
232 | * so that if it was plain text it is now a null-terminated string). |
233 | */ |
4353a5c4 |
234 | int i; |
235 | char *str; |
236 | } adns_rr_intstr; |
237 | |
238 | typedef struct { |
9ec44266 |
239 | adns_rr_intstr array[2]; |
240 | } adns_rr_intstrpair; |
241 | |
242 | typedef struct { |
243 | char *mname, *rname; |
4353a5c4 |
244 | unsigned long serial, refresh, retry, expire, minimum; |
245 | } adns_rr_soa; |
84fe28db |
246 | |
247 | typedef struct { |
a17d3a1d |
248 | adns_status status; |
249 | char *cname; /* always NULL if query was for CNAME records */ |
22181a31 |
250 | char *owner; /* only set if requested in query flags */ |
86e7b8d9 |
251 | adns_rrtype type; /* guaranteed to be same as in query */ |
73dba56e |
252 | time_t expires; /* expiry time, defined only if _s_ok, nxdomain or nodata. NOT TTL! */ |
b365d68a |
253 | int nrrs, rrsz; /* nrrs is 0 if an error occurs */ |
a17d3a1d |
254 | union { |
8e5b0abb |
255 | void *untyped; |
256 | unsigned char *bytes; |
c7836bc9 |
257 | char *(*str); /* ns_raw, cname, ptr, ptr_raw */ |
258 | adns_rr_intstr *(*manyistr); /* txt (list of strings ends with i=-1, str=0) */ |
551ff40f |
259 | adns_rr_addr *addr; /* addr */ |
c7836bc9 |
260 | struct in_addr *inaddr; /* a */ |
261 | adns_rr_hostaddr *hostaddr; /* ns */ |
9ec44266 |
262 | adns_rr_intstrpair *intstrpair; /* hinfo */ |
263 | adns_rr_strpair *strpair; /* rp, rp_raw */ |
c7836bc9 |
264 | adns_rr_inthostaddr *inthostaddr; /* mx */ |
265 | adns_rr_intstr *intstr; /* mx_raw */ |
266 | adns_rr_soa *soa; /* soa, soa_raw */ |
a17d3a1d |
267 | } rrs; |
e8c505a5 |
268 | } adns_answer; |
a17d3a1d |
269 | |
270 | /* Memory management: |
271 | * adns_state and adns_query are actually pointers to malloc'd state; |
272 | * On submission questions are copied, including the owner domain; |
4353a5c4 |
273 | * Answers are malloc'd as a single piece of memory; pointers in the |
274 | * answer struct point into further memory in the answer. |
a17d3a1d |
275 | * query_io: |
276 | * Must always be non-null pointer; |
277 | * If *query_io is 0 to start with then any query may be returned; |
278 | * If *query_io is !0 adns_query then only that query may be returned. |
d3eea642 |
279 | * If the call is successful, *query_io, *answer_r, and *context_r |
280 | * will all be set. |
a17d3a1d |
281 | * Errors: |
620c146d |
282 | * Return values are 0 or an errno value. |
283 | * |
284 | * For _init, _init_strcfg, _submit and _synchronous, system errors |
285 | * (eg, failure to create sockets, malloc failure, etc.) return errno |
286 | * values. |
287 | * |
288 | * For _wait and _check failures are reported in the answer |
289 | * structure, and only 0, ESRCH or (for _check) EWOULDBLOCK is |
290 | * returned: if no (appropriate) requests are done adns_check returns |
291 | * EWOULDBLOCK; if no (appropriate) requests are outstanding both |
292 | * adns_query and adns_wait return ESRCH. |
293 | * |
294 | * Additionally, _wait can return EINTR if you set adns_if_eintr. |
295 | * |
296 | * All other errors (nameserver failure, timed out connections, &c) |
297 | * are returned in the status field of the answer. After a |
298 | * successful _wait or _check, if status is nonzero then nrrs will be |
299 | * 0, otherwise it will be >0. type will always be the type |
300 | * requested. |
a17d3a1d |
301 | */ |
302 | |
36369543 |
303 | int adns_init(adns_state *newstate_r, adns_initflags flags, |
304 | FILE *diagfile /*0=>stderr*/); |
305 | |
306 | int adns_init_strcfg(adns_state *newstate_r, adns_initflags flags, |
307 | FILE *diagfile /*0=>discard*/, const char *configtext); |
a17d3a1d |
308 | |
309 | int adns_synchronous(adns_state ads, |
310 | const char *owner, |
311 | adns_rrtype type, |
72934832 |
312 | adns_queryflags flags, |
9d95094c |
313 | adns_answer **answer_r); |
e8c505a5 |
314 | |
315 | /* NB: if you set adns_if_noautosys then _submit and _check do not |
620c146d |
316 | * make any system calls; you must use some of the asynch-io event |
317 | * processing functions to actually get things to happen. |
e8c505a5 |
318 | */ |
a17d3a1d |
319 | |
320 | int adns_submit(adns_state ads, |
321 | const char *owner, |
322 | adns_rrtype type, |
72934832 |
323 | adns_queryflags flags, |
a17d3a1d |
324 | void *context, |
964344fc |
325 | adns_query *query_r); |
a17d3a1d |
326 | |
964344fc |
327 | int adns_check(adns_state ads, |
a17d3a1d |
328 | adns_query *query_io, |
9d95094c |
329 | adns_answer **answer_r, |
330 | void **context_r); |
a17d3a1d |
331 | |
332 | int adns_wait(adns_state ads, |
333 | adns_query *query_io, |
9d95094c |
334 | adns_answer **answer_r, |
335 | void **context_r); |
a17d3a1d |
336 | |
3955725c |
337 | void adns_cancel(adns_query query); |
a17d3a1d |
338 | |
620c146d |
339 | /* The adns_query you get back from _submit is valid (ie, can be |
340 | * legitimately passed into adns functions) until it is returned by |
341 | * adns_check or adns_wait, or passed to adns_cancel. After that it |
342 | * must not be used. You can rely on it not being reused until the |
343 | * first adns_submit or _transact call using the same adns_state after |
344 | * it became invalid, so you may compare it for equality with other |
345 | * query handles until you next call _query or _transact. |
636b69b1 |
346 | * |
347 | * _submit and _synchronous return ENOSYS if they don't understand the |
348 | * query type. |
e576be50 |
349 | */ |
a17d3a1d |
350 | |
b365d68a |
351 | int adns_submit_reverse(adns_state ads, |
352 | const struct sockaddr *addr, |
353 | adns_rrtype type, |
354 | adns_queryflags flags, |
355 | void *context, |
356 | adns_query *query_r); |
357 | /* type must be _r_ptr or _r_ptr_raw. _qf_search is ignored. */ |
358 | |
620c146d |
359 | void adns_finish(adns_state ads); |
e576be50 |
360 | /* You may call this even if you have queries outstanding; |
361 | * they will be cancelled. |
362 | */ |
a17d3a1d |
363 | |
964344fc |
364 | |
958ad1f0 |
365 | void adns_forallqueries_begin(adns_state ads); |
8ce38e76 |
366 | adns_query adns_forallqueries_next(adns_state ads, void **context_r); |
620c146d |
367 | /* Iterator functions, which you can use to loop over the outstanding |
958ad1f0 |
368 | * (submitted but not yet successfuly checked/waited) queries. |
a8768e80 |
369 | * |
958ad1f0 |
370 | * You can only have one iteration going at once. You may call _begin |
371 | * at any time; after that, an iteration will be in progress. You may |
372 | * only call _next when an iteration is in progress - anything else |
373 | * may coredump. The iteration remains in progress until _next |
374 | * returns 0, indicating that all the queries have been walked over, |
375 | * or ANY other adns function is called with the same adns_state (or a |
376 | * query in the same adns_state). There is no need to explicitly |
377 | * finish an iteration. |
378 | * |
8ce38e76 |
379 | * context_r may be 0. *context_r may not be set when _next returns 0. |
964344fc |
380 | */ |
a17d3a1d |
381 | |
620c146d |
382 | /* |
383 | * Example expected/legal calling sequence for submit/check/wait: |
a17d3a1d |
384 | * adns_init |
385 | * adns_submit 1 |
386 | * adns_submit 2 |
387 | * adns_submit 3 |
388 | * adns_wait 1 |
964344fc |
389 | * adns_check 3 -> EWOULDBLOCK |
a17d3a1d |
390 | * adns_wait 2 |
391 | * adns_wait 3 |
392 | * .... |
393 | * adns_finish |
620c146d |
394 | */ |
395 | |
396 | /* |
397 | * Entrypoints for generic asynch io: |
398 | * (these entrypoints are not very useful except in combination with * |
399 | * some of the other I/O model calls which can tell you which fds to |
400 | * be interested in): |
401 | * |
402 | * Note that any adns call may cause adns to open and close fds, so |
403 | * you must call beforeselect or beforepoll again just before |
404 | * blocking, or you may not have an up-to-date list of it's fds. |
405 | */ |
406 | |
407 | int adns_processany(adns_state ads); |
408 | /* Gives adns flow-of-control for a bit. This will never block, and |
409 | * can be used with any threading/asynch-io model. If some error |
410 | * occurred which might cause an event loop to spin then the errno |
411 | * value is returned. |
412 | */ |
413 | |
414 | int adns_processreadable(adns_state ads, int fd, const struct timeval *now); |
415 | int adns_processwriteable(adns_state ads, int fd, const struct timeval *now); |
416 | int adns_processexceptional(adns_state ads, int fd, const struct timeval *now); |
417 | /* Gives adns flow-of-control so that it can process incoming data |
418 | * from, or send outgoing data via, fd. Very like _processany. If it |
419 | * returns zero then fd will no longer be readable or writeable |
420 | * (unless of course more data has arrived since). adns will _only_ |
421 | * that fd and only in the manner specified, regardless of whether |
422 | * adns_if_noautosys was specified. |
423 | * |
424 | * adns_processexceptional should be called when select(2) reports an |
425 | * exceptional condition, or poll(2) reports POLLPRI. |
426 | * |
427 | * It is fine to call _processreabable or _processwriteable when the |
428 | * fd is not ready, or with an fd that doesn't belong to adns; it will |
429 | * then just return 0. |
430 | * |
431 | * If some error occurred which might prevent an event loop to spin |
432 | * then the errno value is returned. |
433 | */ |
434 | |
435 | void adns_processtimeouts(adns_state ads, const struct timeval *now); |
436 | /* Gives adns flow-of-control so that it can process any timeouts |
437 | * which might have happened. Very like _processreadable/writeable. |
438 | * |
439 | * now may be 0; if it isn't, *now must be the current time, recently |
440 | * obtained from gettimeofday. |
441 | */ |
442 | |
443 | void adns_firsttimeout(adns_state ads, |
444 | struct timeval **tv_mod, struct timeval *tv_buf, |
445 | struct timeval now); |
446 | /* Asks adns when it would first like the opportunity to time |
447 | * something out. now must be the current time, from gettimeofday. |
448 | * |
449 | * If tv_mod points to 0 then tv_buf must be non-null, and |
450 | * _firsttimeout will fill in *tv_buf with the time until the first |
451 | * timeout, and make *tv_mod point to tv_buf. If adns doesn't have |
452 | * anything that might need timing out it will leave *tv_mod as 0. |
453 | * |
454 | * If *tv_mod is not 0 then tv_buf is not used. adns will update |
455 | * *tv_mod if it has any earlier timeout, and leave it alone if it |
456 | * doesn't. |
457 | * |
458 | * This call will not actually do any I/O, or change the fds that adns |
459 | * is using. It always succeeds and never blocks. |
460 | */ |
461 | |
462 | void adns_globalsystemfailure(adns_state ads); |
463 | /* If serious problem(s) happen which globally affect your ability to |
464 | * interact properly with adns, or adns's ability to function |
465 | * properly, you or adns can call this function. |
466 | * |
467 | * All currently outstanding queries will be made to fail with |
468 | * adns_s_systemfail, and adns will close any stream sockets it has |
469 | * open. |
470 | * |
471 | * This is used by adns, for example, if gettimeofday() fails. |
472 | * Without this the program's event loop might start to spin ! |
473 | * |
474 | * This call will never block. |
475 | */ |
476 | |
477 | /* |
478 | * Entrypoints for select-loop based asynch io: |
479 | */ |
480 | |
481 | void adns_beforeselect(adns_state ads, int *maxfd, fd_set *readfds, |
482 | fd_set *writefds, fd_set *exceptfds, |
483 | struct timeval **tv_mod, struct timeval *tv_buf, |
484 | const struct timeval *now); |
485 | /* Find out file descriptors adns is interested in, and when it would |
486 | * like the opportunity to time something out. If you do not plan to |
487 | * block then tv_mod may be 0. Otherwise, tv_mod and tv_buf are as |
488 | * for adns_firsttimeout. readfds, writefds, exceptfds and maxfd_io may |
489 | * not be 0. |
490 | * |
491 | * If *now is not 0 then this will never actually do any I/O, or |
492 | * change the fds that adns is using or the timeouts it wants. In any |
493 | * case it won't block. |
494 | */ |
495 | |
496 | void adns_afterselect(adns_state ads, int maxfd, const fd_set *readfds, |
497 | const fd_set *writefds, const fd_set *exceptfds, |
498 | const struct timeval *now); |
499 | /* Gives adns flow-of-control for a bit; intended for use after |
500 | * select. This is just a fancy way of calling adns_processreadable/ |
501 | * writeable/timeouts as appropriate, as if select had returned the |
502 | * data being passed. Always succeeds. |
503 | */ |
504 | |
505 | /* |
506 | * Example calling sequence: |
a17d3a1d |
507 | * |
e8c505a5 |
508 | * adns_init _noautosys |
a17d3a1d |
509 | * loop { |
620c146d |
510 | * adns_beforeselect |
a17d3a1d |
511 | * select |
620c146d |
512 | * adns_afterselect |
e8c505a5 |
513 | * ... |
514 | * adns_submit / adns_check |
515 | * ... |
a17d3a1d |
516 | * } |
517 | */ |
518 | |
620c146d |
519 | /* |
520 | * Entrypoints for poll-loop based asynch io: |
521 | */ |
522 | |
523 | struct pollfd; |
524 | /* In case your system doesn't have it or you forgot to include |
525 | * <sys/poll.h>, to stop the following declarations from causing |
526 | * problems. If your system doesn't have poll then the following |
527 | * entrypoints will not be defined in libadns. Sorry ! |
528 | */ |
529 | |
530 | int adns_beforepoll(adns_state ads, struct pollfd *fds, int *nfds_io, int *timeout_io, |
531 | const struct timeval *now); |
532 | /* Finds out which fd's adns is interested in, and when it would like |
533 | * to be able to time things out. This is in a form suitable for use |
534 | * with poll(2). |
535 | * |
536 | * On entry, usually fds should point to at least *nfds_io structs. |
537 | * adns will fill up to that many structs will information for poll, |
538 | * and record in *nfds_io how many structs it filled. If it wants to |
539 | * listen for more structs then *nfds_io will be set to the number |
540 | * required and _beforepoll will return ERANGE. |
541 | * |
620c146d |
542 | * You may call _beforepoll with fds==0 and *nfds_io 0, in which case |
543 | * adns will fill in the number of fds that it might be interested in |
fc6a52ae |
544 | * in *nfds_io, and always return either 0 (if it is not interested in |
545 | * any fds) or ERANGE (if it is). |
546 | * |
547 | * NOTE that (unless timeout_io is 0) adns may acquire additional fds |
548 | * from one call to the next, so you must put adns_beforepoll in a |
549 | * loop, rather than assuming that the second call (with the buffer |
550 | * size requested by the first) will not return ERANGE. |
620c146d |
551 | * |
552 | * adns only ever sets POLLIN, POLLOUT and POLLPRI in its pollfd |
553 | * structs, and only ever looks at those bits. POLLPRI is required to |
fc6a52ae |
554 | * detect TCP Urgent Data (which should not be used by a DNS server) |
620c146d |
555 | * so that adns can know that the TCP stream is now useless. |
556 | * |
557 | * In any case, *timeout_io should be a timeout value as for poll(2), |
558 | * which adns will modify downwards as required. If the caller does |
fc6a52ae |
559 | * not plan to block then *timeout_io should be 0 on entry, or |
560 | * alternatively, timeout_io may be 0. (Alternatively, the caller may |
561 | * use _beforeselect with timeout_io==0 to find out about file |
562 | * descriptors, and use _firsttimeout is used to find out when adns |
563 | * might want to time something out.) |
620c146d |
564 | * |
565 | * adns_beforepoll will return 0 on success, and will not fail for any |
566 | * reason other than the fds buffer being too small (ERANGE). |
567 | * |
fc6a52ae |
568 | * This call will never actually do any I/O, or change the fds that |
569 | * adns is using or the timeouts it wants; and in any case it won't |
570 | * block. |
620c146d |
571 | */ |
572 | |
573 | #define ADNS_POLLFDS_RECOMMENDED 2 |
574 | /* If you allocate an fds buf with at least RECOMMENDED entries then |
575 | * you are unlikely to need to enlarge it. You are recommended to do |
576 | * so if it's convenient. However, you must be prepared for adns to |
577 | * require more space than this. |
578 | */ |
579 | |
580 | void adns_afterpoll(adns_state ads, const struct pollfd *fds, int nfds, |
581 | const struct timeval *now); |
582 | /* Gives adns flow-of-control for a bit; intended for use after |
583 | * poll(2). fds and nfds should be the results from poll(). pollfd |
584 | * structs mentioning fds not belonging to adns will be ignored. |
585 | */ |
586 | |
587 | |
86e7b8d9 |
588 | adns_status adns_rr_info(adns_rrtype type, |
589 | const char **rrtname_r, const char **fmtname_r, |
590 | int *len_r, |
591 | const void *datap, char **data_r); |
b365d68a |
592 | /* |
593 | |
594 | * Get information about a query type, or convert reply data to a |
595 | * textual form. type must be specified, and the official name of the |
596 | * corresponding RR type will be returned in *rrtname_r, and |
597 | * information about the processing style in *fmtname_r. The length |
598 | * of the table entry in an answer for that type will be returned in |
599 | * in *len_r. Any or all of rrtname_r, fmtname_r and len_r may be 0. |
600 | * If fmtname_r is non-null then *fmtname_r may be null on return, |
601 | * indicating that no special processing is involved. |
602 | * |
603 | * data_r be must be non-null iff datap is. In this case *data_r will |
604 | * be set to point to a string pointing to a representation of the RR |
605 | * data in master file format. (The owner name, timeout, class and |
606 | * type will not be present - only the data part of the RR.) The |
607 | * memory will have been obtained from malloc() and must be freed by |
608 | * the caller. |
86e7b8d9 |
609 | * |
610 | * Usually this routine will succeed. Possible errors include: |
611 | * adns_s_nomemory |
ea1e31e3 |
612 | * adns_s_rrtypeunknown |
86e7b8d9 |
613 | * adns_s_invaliddata (*datap contained garbage) |
614 | * If an error occurs then no memory has been allocated, |
615 | * and *rrtname_r, *fmtname_r, *len_r and *data_r are undefined. |
b365d68a |
616 | * |
617 | * There are some adns-invented data formats which are not official |
618 | * master file formats. These include: |
619 | * |
620 | * Mailboxes if __qtf_mail822: these are just included as-is. |
621 | * |
622 | * Addresses (adns_rr_addr): these may be of pretty much any type. |
623 | * The representation is in two parts: first, a word for the address |
624 | * family (ie, in AF_XXX, the XXX), and then one or more items for the |
625 | * address itself, depending on the format. For an IPv4 address the |
626 | * syntax is INET followed by the dotted quad (from inet_ntoa). |
627 | * Currently only IPv4 is supported. |
628 | * |
a6f1dc92 |
629 | * Text strings (as in adns_rr_txt) appear inside double quotes, and |
630 | * use \" and \\ to represent " and \, and \xHH to represent |
631 | * characters not in the range 32-126. |
632 | * |
b365d68a |
633 | * Hostname with addresses (adns_rr_hostaddr): this consists of the |
a6f1dc92 |
634 | * hostname, as usual, followed by the adns_status value, as an |
635 | * abbreviation, and then a descriptive string (encoded as if it were |
636 | * a piece of text), for the address lookup, followed by zero or more |
b365d68a |
637 | * addresses enclosed in ( and ). If the result was a permanent |
638 | * failure, then a single ? appears instead of the ( ). If the |
639 | * result was a temporary failure then an empty pair of parentheses |
640 | * appears (which a space in between). For example, one of the NS |
a6f1dc92 |
641 | * records for greenend.org.uk comes out like |
642 | * ns.chiark.greenend.org.uk ok "OK" ( INET 195.224.76.132 ) |
b365d68a |
643 | * an MX referring to a nonexistent host might come out like: |
a6f1dc92 |
644 | * 50 sun2.nsfnet-relay.ac.uk nxdomain "No such domain" ( ) |
b365d68a |
645 | * and if nameserver information is not available you might get: |
a6f1dc92 |
646 | * dns2.spong.dyn.ml.org timeout "DNS query timed out" ? |
86e7b8d9 |
647 | */ |
648 | |
31144a72 |
649 | const char *adns_strerror(adns_status st); |
9da4a044 |
650 | const char *adns_errabbrev(adns_status st); |
620c146d |
651 | /* Like strerror but for adns_status values. adns_errabbrev returns |
652 | * the abbreviation of the error - eg, for adns_s_timeout it returns |
653 | * "timeout". You MUST NOT call these functions with status values |
654 | * not returned by the same adns library. |
655 | */ |
31144a72 |
656 | |
02b47faa |
657 | #ifdef __cplusplus |
658 | } /* end of extern "C" */ |
659 | #endif |
a17d3a1d |
660 | #endif |