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 |
27 | |
4353a5c4 |
28 | #include <stdio.h> |
29 | |
964344fc |
30 | #include <sys/socket.h> |
31 | #include <netinet/in.h> |
32 | |
09957b1c |
33 | /* All struct in_addr anywhere in adns are in NETWORK byte order. */ |
34 | |
964344fc |
35 | typedef struct adns__state *adns_state; |
36 | typedef struct adns__query *adns_query; |
a17d3a1d |
37 | |
38 | typedef enum { |
37e28fde |
39 | adns_if_noenv= 0x0001, /* do not look at environment */ |
40 | adns_if_noerrprint= 0x0002, /* never print output to stderr (_debug overrides) */ |
41 | adns_if_noserverwarn= 0x0004, /* do not warn to stderr about duff nameservers etc */ |
ddfda861 |
42 | adns_if_debug= 0x0008, /* enable all output to stderr plus debug msgs */ |
37e28fde |
43 | adns_if_noautosys= 0x0010, /* do not make syscalls at every opportunity */ |
88372443 |
44 | adns_if_eintr= 0x0020, /* allow _wait and _synchronous to return EINTR */ |
ac868fa8 |
45 | adns_if_nosigpipe= 0x0040, /* applic has SIGPIPE set to SIG_IGN, do not protect */ |
a17d3a1d |
46 | } adns_initflags; |
47 | |
48 | typedef enum { |
828d89bd |
49 | adns_qf_search= 0x000001, /* use the searchlist */ |
50 | adns_qf_usevc= 0x000002, /* use a virtual circuit (TCP connection) */ |
22181a31 |
51 | adns_qf_owner= 0x000004, /* fill in the owner field in the answer */ |
828d89bd |
52 | adns_qf_quoteok_query= 0x000010, /* allow quote-requiring chars in query domain */ |
53 | adns_qf_quoteok_cname= 0x000020, /* allow ... in CNAME we go via */ |
54 | adns_qf_quoteok_anshost= 0x000040, /* allow ... in answers expected to be hostnames */ |
55 | adns_qf_cname_loose= 0x000100, /* allow refs to CNAMEs - without, get _s_cname */ |
56 | adns_qf_cname_forbid= 0x000200, /* don't follow CNAMEs, instead give _s_cname */ |
57 | adns__qf_internalmask= 0x0ff000 |
a17d3a1d |
58 | } adns_queryflags; |
59 | |
60 | typedef enum { |
350d37d9 |
61 | adns__rrt_typemask= 0x0ffff, |
ddfda861 |
62 | adns__qtf_deref= 0x10000, /* dereference domains and perhaps produce extra data */ |
63 | adns__qtf_mail822= 0x20000, /* make mailboxes be in RFC822 rcpt field format */ |
ddfda861 |
64 | |
350d37d9 |
65 | adns_r_none= 0, |
ddfda861 |
66 | |
350d37d9 |
67 | adns_r_a= 1, |
ddfda861 |
68 | |
350d37d9 |
69 | adns_r_ns_raw= 2, |
70 | adns_r_ns= adns_r_ns_raw|adns__qtf_deref, |
ddfda861 |
71 | |
350d37d9 |
72 | adns_r_cname= 5, |
ddfda861 |
73 | |
350d37d9 |
74 | adns_r_soa_raw= 6, |
ddfda861 |
75 | adns_r_soa= adns_r_soa_raw|adns__qtf_mail822, |
ddfda861 |
76 | |
350d37d9 |
77 | adns_r_ptr_raw= 12, |
78 | adns_r_ptr= adns_r_ptr_raw|adns__qtf_deref, |
ddfda861 |
79 | |
350d37d9 |
80 | adns_r_hinfo= 13, |
ddfda861 |
81 | |
350d37d9 |
82 | adns_r_mx_raw= 15, |
83 | adns_r_mx= adns_r_mx_raw|adns__qtf_deref, |
ddfda861 |
84 | |
350d37d9 |
85 | adns_r_txt= 16, |
ddfda861 |
86 | |
350d37d9 |
87 | adns_r_rp_raw= 17, |
4353a5c4 |
88 | adns_r_rp= adns_r_rp_raw|adns__qtf_mail822, |
828d89bd |
89 | |
90 | adns_r_addr= adns_r_a|adns__qtf_deref |
ddfda861 |
91 | |
a17d3a1d |
92 | } adns_rrtype; |
93 | |
9da4a044 |
94 | /* In queries without qf_quoteok_*, all domains must have standard |
95 | * legal syntax. In queries _with_ qf_quoteok_*, domains in the query |
96 | * or response may contain any characters, quoted according to RFC1035 |
97 | * 5.1. On input to adns, the char* is a pointer to the interior of a |
98 | * " delimited string, except that " may appear in it, and on output, |
99 | * the char* is a pointer to a string which would be legal either |
100 | * inside or outside " delimiters, and any characters not usually |
101 | * legal in domain names will be quoted as \X (if the character is |
102 | * 33-126 except \ and ") or \DDD. |
964344fc |
103 | * |
ddfda861 |
104 | * Do not ask for _raw records containing mailboxes without |
105 | * specifying _qf_anyquote. |
964344fc |
106 | */ |
107 | |
a17d3a1d |
108 | typedef enum { |
109 | adns_s_ok, |
ea1e31e3 |
110 | |
111 | /* locally induced errors */ |
112 | adns_s_nomemory, |
113 | adns_s_unknownrrtype, |
620c146d |
114 | adns_s_systemfail, |
115 | |
116 | adns_s_max_localfail= 29, |
ea1e31e3 |
117 | |
118 | /* remotely induced errors, detected locally */ |
37e28fde |
119 | adns_s_timeout, |
4bec51a4 |
120 | adns_s_allservfail, |
ec477b9e |
121 | adns_s_norecurse, |
ea1e31e3 |
122 | adns_s_invalidresponse, |
123 | adns_s_unknownformat, |
620c146d |
124 | |
125 | adns_s_max_remotefail= 59, |
ea1e31e3 |
126 | |
127 | /* remotely induced errors, reported by remote server to us */ |
128 | adns_s_rcodeservfail, |
129 | adns_s_rcodeformaterror, |
130 | adns_s_rcodenotimplemented, |
131 | adns_s_rcoderefused, |
132 | adns_s_rcodeunknown, |
620c146d |
133 | |
b9de380c |
134 | adns_s_max_tempfail= 99, |
ea1e31e3 |
135 | |
136 | /* remote configuration errors */ |
137 | adns_s_inconsistent, /* PTR gives domain whose A does not exist and match */ |
138 | adns_s_prohibitedcname, /* CNAME found where eg A expected (not if _qf_loosecname) */ |
139 | adns_s_answerdomaininvalid, |
140 | adns_s_answerdomaintoolong, |
141 | adns_s_invaliddata, |
142 | |
143 | adns_s_max_misconfig= 199, |
144 | |
ea1e31e3 |
145 | /* permanent problems with the query */ |
146 | adns_s_querydomainwrong, |
147 | adns_s_querydomaininvalid, |
148 | adns_s_querydomaintoolong, |
149 | |
150 | adns_s_max_misquery= 299, |
151 | |
152 | /* permanent errors */ |
a17d3a1d |
153 | adns_s_nxdomain, |
0ba0614a |
154 | adns_s_nodata, |
ea1e31e3 |
155 | |
a17d3a1d |
156 | } adns_status; |
157 | |
e8c505a5 |
158 | typedef struct { |
828d89bd |
159 | int len; |
160 | union { |
161 | struct sockaddr sa; |
162 | struct sockaddr_in inet; |
163 | } addr; |
551ff40f |
164 | } adns_rr_addr; |
828d89bd |
165 | |
166 | typedef struct { |
1dfe95d8 |
167 | char *host; |
84fe28db |
168 | adns_status astatus; |
169 | int naddrs; /* temp fail => -1, perm fail => 0, s_ok => >0 */ |
551ff40f |
170 | adns_rr_addr *addrs; |
c7836bc9 |
171 | } adns_rr_hostaddr; |
4353a5c4 |
172 | |
173 | typedef struct { |
9ec44266 |
174 | char *(array[2]); |
4353a5c4 |
175 | } adns_rr_strpair; |
176 | |
177 | typedef struct { |
178 | int i; |
1dfe95d8 |
179 | adns_rr_hostaddr ha; |
c7836bc9 |
180 | } adns_rr_inthostaddr; |
4353a5c4 |
181 | |
182 | typedef struct { |
e062dcae |
183 | /* Used both for mx_raw, in which case i is the preference and str the domain, |
184 | * and for txt, in which case each entry has i for the `text' length, |
185 | * and str for the data (which will have had an extra nul appended |
186 | * so that if it was plain text it is now a null-terminated string). |
187 | */ |
4353a5c4 |
188 | int i; |
189 | char *str; |
190 | } adns_rr_intstr; |
191 | |
192 | typedef struct { |
9ec44266 |
193 | adns_rr_intstr array[2]; |
194 | } adns_rr_intstrpair; |
195 | |
196 | typedef struct { |
197 | char *mname, *rname; |
4353a5c4 |
198 | unsigned long serial, refresh, retry, expire, minimum; |
199 | } adns_rr_soa; |
84fe28db |
200 | |
201 | typedef struct { |
a17d3a1d |
202 | adns_status status; |
203 | char *cname; /* always NULL if query was for CNAME records */ |
22181a31 |
204 | char *owner; /* only set if requested in query flags */ |
86e7b8d9 |
205 | adns_rrtype type; /* guaranteed to be same as in query */ |
73dba56e |
206 | time_t expires; /* expiry time, defined only if _s_ok, nxdomain or nodata. NOT TTL! */ |
8e5b0abb |
207 | int nrrs, rrsz; |
a17d3a1d |
208 | union { |
8e5b0abb |
209 | void *untyped; |
210 | unsigned char *bytes; |
c7836bc9 |
211 | char *(*str); /* ns_raw, cname, ptr, ptr_raw */ |
212 | adns_rr_intstr *(*manyistr); /* txt (list of strings ends with i=-1, str=0) */ |
551ff40f |
213 | adns_rr_addr *addr; /* addr */ |
c7836bc9 |
214 | struct in_addr *inaddr; /* a */ |
215 | adns_rr_hostaddr *hostaddr; /* ns */ |
9ec44266 |
216 | adns_rr_intstrpair *intstrpair; /* hinfo */ |
217 | adns_rr_strpair *strpair; /* rp, rp_raw */ |
c7836bc9 |
218 | adns_rr_inthostaddr *inthostaddr; /* mx */ |
219 | adns_rr_intstr *intstr; /* mx_raw */ |
220 | adns_rr_soa *soa; /* soa, soa_raw */ |
a17d3a1d |
221 | } rrs; |
e8c505a5 |
222 | } adns_answer; |
a17d3a1d |
223 | |
224 | /* Memory management: |
225 | * adns_state and adns_query are actually pointers to malloc'd state; |
226 | * On submission questions are copied, including the owner domain; |
4353a5c4 |
227 | * Answers are malloc'd as a single piece of memory; pointers in the |
228 | * answer struct point into further memory in the answer. |
a17d3a1d |
229 | * query_io: |
230 | * Must always be non-null pointer; |
231 | * If *query_io is 0 to start with then any query may be returned; |
232 | * If *query_io is !0 adns_query then only that query may be returned. |
d3eea642 |
233 | * If the call is successful, *query_io, *answer_r, and *context_r |
234 | * will all be set. |
a17d3a1d |
235 | * Errors: |
620c146d |
236 | * Return values are 0 or an errno value. |
237 | * |
238 | * For _init, _init_strcfg, _submit and _synchronous, system errors |
239 | * (eg, failure to create sockets, malloc failure, etc.) return errno |
240 | * values. |
241 | * |
242 | * For _wait and _check failures are reported in the answer |
243 | * structure, and only 0, ESRCH or (for _check) EWOULDBLOCK is |
244 | * returned: if no (appropriate) requests are done adns_check returns |
245 | * EWOULDBLOCK; if no (appropriate) requests are outstanding both |
246 | * adns_query and adns_wait return ESRCH. |
247 | * |
248 | * Additionally, _wait can return EINTR if you set adns_if_eintr. |
249 | * |
250 | * All other errors (nameserver failure, timed out connections, &c) |
251 | * are returned in the status field of the answer. After a |
252 | * successful _wait or _check, if status is nonzero then nrrs will be |
253 | * 0, otherwise it will be >0. type will always be the type |
254 | * requested. |
a17d3a1d |
255 | */ |
256 | |
36369543 |
257 | int adns_init(adns_state *newstate_r, adns_initflags flags, |
258 | FILE *diagfile /*0=>stderr*/); |
259 | |
260 | int adns_init_strcfg(adns_state *newstate_r, adns_initflags flags, |
261 | FILE *diagfile /*0=>discard*/, const char *configtext); |
a17d3a1d |
262 | |
263 | int adns_synchronous(adns_state ads, |
264 | const char *owner, |
265 | adns_rrtype type, |
72934832 |
266 | adns_queryflags flags, |
9d95094c |
267 | adns_answer **answer_r); |
e8c505a5 |
268 | |
269 | /* NB: if you set adns_if_noautosys then _submit and _check do not |
620c146d |
270 | * make any system calls; you must use some of the asynch-io event |
271 | * processing functions to actually get things to happen. |
e8c505a5 |
272 | */ |
a17d3a1d |
273 | |
274 | int adns_submit(adns_state ads, |
275 | const char *owner, |
276 | adns_rrtype type, |
72934832 |
277 | adns_queryflags flags, |
a17d3a1d |
278 | void *context, |
964344fc |
279 | adns_query *query_r); |
a17d3a1d |
280 | |
964344fc |
281 | int adns_check(adns_state ads, |
a17d3a1d |
282 | adns_query *query_io, |
9d95094c |
283 | adns_answer **answer_r, |
284 | void **context_r); |
a17d3a1d |
285 | |
286 | int adns_wait(adns_state ads, |
287 | adns_query *query_io, |
9d95094c |
288 | adns_answer **answer_r, |
289 | void **context_r); |
a17d3a1d |
290 | |
3955725c |
291 | void adns_cancel(adns_query query); |
a17d3a1d |
292 | |
620c146d |
293 | /* The adns_query you get back from _submit is valid (ie, can be |
294 | * legitimately passed into adns functions) until it is returned by |
295 | * adns_check or adns_wait, or passed to adns_cancel. After that it |
296 | * must not be used. You can rely on it not being reused until the |
297 | * first adns_submit or _transact call using the same adns_state after |
298 | * it became invalid, so you may compare it for equality with other |
299 | * query handles until you next call _query or _transact. |
e576be50 |
300 | */ |
a17d3a1d |
301 | |
620c146d |
302 | void adns_finish(adns_state ads); |
e576be50 |
303 | /* You may call this even if you have queries outstanding; |
304 | * they will be cancelled. |
305 | */ |
a17d3a1d |
306 | |
964344fc |
307 | |
958ad1f0 |
308 | void adns_forallqueries_begin(adns_state ads); |
309 | struct adns_query adns_forallqueries_next(adns_state ads, void **context_r); |
620c146d |
310 | /* Iterator functions, which you can use to loop over the outstanding |
958ad1f0 |
311 | * (submitted but not yet successfuly checked/waited) queries. |
a8768e80 |
312 | * |
958ad1f0 |
313 | * You can only have one iteration going at once. You may call _begin |
314 | * at any time; after that, an iteration will be in progress. You may |
315 | * only call _next when an iteration is in progress - anything else |
316 | * may coredump. The iteration remains in progress until _next |
317 | * returns 0, indicating that all the queries have been walked over, |
318 | * or ANY other adns function is called with the same adns_state (or a |
319 | * query in the same adns_state). There is no need to explicitly |
320 | * finish an iteration. |
321 | * |
322 | * context_r may be 0. |
964344fc |
323 | */ |
a17d3a1d |
324 | |
620c146d |
325 | /* |
326 | * Example expected/legal calling sequence for submit/check/wait: |
a17d3a1d |
327 | * adns_init |
328 | * adns_submit 1 |
329 | * adns_submit 2 |
330 | * adns_submit 3 |
331 | * adns_wait 1 |
964344fc |
332 | * adns_check 3 -> EWOULDBLOCK |
a17d3a1d |
333 | * adns_wait 2 |
334 | * adns_wait 3 |
335 | * .... |
336 | * adns_finish |
620c146d |
337 | */ |
338 | |
339 | /* |
340 | * Entrypoints for generic asynch io: |
341 | * (these entrypoints are not very useful except in combination with * |
342 | * some of the other I/O model calls which can tell you which fds to |
343 | * be interested in): |
344 | * |
345 | * Note that any adns call may cause adns to open and close fds, so |
346 | * you must call beforeselect or beforepoll again just before |
347 | * blocking, or you may not have an up-to-date list of it's fds. |
348 | */ |
349 | |
350 | int adns_processany(adns_state ads); |
351 | /* Gives adns flow-of-control for a bit. This will never block, and |
352 | * can be used with any threading/asynch-io model. If some error |
353 | * occurred which might cause an event loop to spin then the errno |
354 | * value is returned. |
355 | */ |
356 | |
357 | int adns_processreadable(adns_state ads, int fd, const struct timeval *now); |
358 | int adns_processwriteable(adns_state ads, int fd, const struct timeval *now); |
359 | int adns_processexceptional(adns_state ads, int fd, const struct timeval *now); |
360 | /* Gives adns flow-of-control so that it can process incoming data |
361 | * from, or send outgoing data via, fd. Very like _processany. If it |
362 | * returns zero then fd will no longer be readable or writeable |
363 | * (unless of course more data has arrived since). adns will _only_ |
364 | * that fd and only in the manner specified, regardless of whether |
365 | * adns_if_noautosys was specified. |
366 | * |
367 | * adns_processexceptional should be called when select(2) reports an |
368 | * exceptional condition, or poll(2) reports POLLPRI. |
369 | * |
370 | * It is fine to call _processreabable or _processwriteable when the |
371 | * fd is not ready, or with an fd that doesn't belong to adns; it will |
372 | * then just return 0. |
373 | * |
374 | * If some error occurred which might prevent an event loop to spin |
375 | * then the errno value is returned. |
376 | */ |
377 | |
378 | void adns_processtimeouts(adns_state ads, const struct timeval *now); |
379 | /* Gives adns flow-of-control so that it can process any timeouts |
380 | * which might have happened. Very like _processreadable/writeable. |
381 | * |
382 | * now may be 0; if it isn't, *now must be the current time, recently |
383 | * obtained from gettimeofday. |
384 | */ |
385 | |
386 | void adns_firsttimeout(adns_state ads, |
387 | struct timeval **tv_mod, struct timeval *tv_buf, |
388 | struct timeval now); |
389 | /* Asks adns when it would first like the opportunity to time |
390 | * something out. now must be the current time, from gettimeofday. |
391 | * |
392 | * If tv_mod points to 0 then tv_buf must be non-null, and |
393 | * _firsttimeout will fill in *tv_buf with the time until the first |
394 | * timeout, and make *tv_mod point to tv_buf. If adns doesn't have |
395 | * anything that might need timing out it will leave *tv_mod as 0. |
396 | * |
397 | * If *tv_mod is not 0 then tv_buf is not used. adns will update |
398 | * *tv_mod if it has any earlier timeout, and leave it alone if it |
399 | * doesn't. |
400 | * |
401 | * This call will not actually do any I/O, or change the fds that adns |
402 | * is using. It always succeeds and never blocks. |
403 | */ |
404 | |
405 | void adns_globalsystemfailure(adns_state ads); |
406 | /* If serious problem(s) happen which globally affect your ability to |
407 | * interact properly with adns, or adns's ability to function |
408 | * properly, you or adns can call this function. |
409 | * |
410 | * All currently outstanding queries will be made to fail with |
411 | * adns_s_systemfail, and adns will close any stream sockets it has |
412 | * open. |
413 | * |
414 | * This is used by adns, for example, if gettimeofday() fails. |
415 | * Without this the program's event loop might start to spin ! |
416 | * |
417 | * This call will never block. |
418 | */ |
419 | |
420 | /* |
421 | * Entrypoints for select-loop based asynch io: |
422 | */ |
423 | |
424 | void adns_beforeselect(adns_state ads, int *maxfd, fd_set *readfds, |
425 | fd_set *writefds, fd_set *exceptfds, |
426 | struct timeval **tv_mod, struct timeval *tv_buf, |
427 | const struct timeval *now); |
428 | /* Find out file descriptors adns is interested in, and when it would |
429 | * like the opportunity to time something out. If you do not plan to |
430 | * block then tv_mod may be 0. Otherwise, tv_mod and tv_buf are as |
431 | * for adns_firsttimeout. readfds, writefds, exceptfds and maxfd_io may |
432 | * not be 0. |
433 | * |
434 | * If *now is not 0 then this will never actually do any I/O, or |
435 | * change the fds that adns is using or the timeouts it wants. In any |
436 | * case it won't block. |
437 | */ |
438 | |
439 | void adns_afterselect(adns_state ads, int maxfd, const fd_set *readfds, |
440 | const fd_set *writefds, const fd_set *exceptfds, |
441 | const struct timeval *now); |
442 | /* Gives adns flow-of-control for a bit; intended for use after |
443 | * select. This is just a fancy way of calling adns_processreadable/ |
444 | * writeable/timeouts as appropriate, as if select had returned the |
445 | * data being passed. Always succeeds. |
446 | */ |
447 | |
448 | /* |
449 | * Example calling sequence: |
a17d3a1d |
450 | * |
e8c505a5 |
451 | * adns_init _noautosys |
a17d3a1d |
452 | * loop { |
620c146d |
453 | * adns_beforeselect |
a17d3a1d |
454 | * select |
620c146d |
455 | * adns_afterselect |
e8c505a5 |
456 | * ... |
457 | * adns_submit / adns_check |
458 | * ... |
a17d3a1d |
459 | * } |
460 | */ |
461 | |
620c146d |
462 | /* |
463 | * Entrypoints for poll-loop based asynch io: |
464 | */ |
465 | |
466 | struct pollfd; |
467 | /* In case your system doesn't have it or you forgot to include |
468 | * <sys/poll.h>, to stop the following declarations from causing |
469 | * problems. If your system doesn't have poll then the following |
470 | * entrypoints will not be defined in libadns. Sorry ! |
471 | */ |
472 | |
473 | int adns_beforepoll(adns_state ads, struct pollfd *fds, int *nfds_io, int *timeout_io, |
474 | const struct timeval *now); |
475 | /* Finds out which fd's adns is interested in, and when it would like |
476 | * to be able to time things out. This is in a form suitable for use |
477 | * with poll(2). |
478 | * |
479 | * On entry, usually fds should point to at least *nfds_io structs. |
480 | * adns will fill up to that many structs will information for poll, |
481 | * and record in *nfds_io how many structs it filled. If it wants to |
482 | * listen for more structs then *nfds_io will be set to the number |
483 | * required and _beforepoll will return ERANGE. |
484 | * |
620c146d |
485 | * You may call _beforepoll with fds==0 and *nfds_io 0, in which case |
486 | * adns will fill in the number of fds that it might be interested in |
fc6a52ae |
487 | * in *nfds_io, and always return either 0 (if it is not interested in |
488 | * any fds) or ERANGE (if it is). |
489 | * |
490 | * NOTE that (unless timeout_io is 0) adns may acquire additional fds |
491 | * from one call to the next, so you must put adns_beforepoll in a |
492 | * loop, rather than assuming that the second call (with the buffer |
493 | * size requested by the first) will not return ERANGE. |
620c146d |
494 | * |
495 | * adns only ever sets POLLIN, POLLOUT and POLLPRI in its pollfd |
496 | * structs, and only ever looks at those bits. POLLPRI is required to |
fc6a52ae |
497 | * detect TCP Urgent Data (which should not be used by a DNS server) |
620c146d |
498 | * so that adns can know that the TCP stream is now useless. |
499 | * |
500 | * In any case, *timeout_io should be a timeout value as for poll(2), |
501 | * which adns will modify downwards as required. If the caller does |
fc6a52ae |
502 | * not plan to block then *timeout_io should be 0 on entry, or |
503 | * alternatively, timeout_io may be 0. (Alternatively, the caller may |
504 | * use _beforeselect with timeout_io==0 to find out about file |
505 | * descriptors, and use _firsttimeout is used to find out when adns |
506 | * might want to time something out.) |
620c146d |
507 | * |
508 | * adns_beforepoll will return 0 on success, and will not fail for any |
509 | * reason other than the fds buffer being too small (ERANGE). |
510 | * |
fc6a52ae |
511 | * This call will never actually do any I/O, or change the fds that |
512 | * adns is using or the timeouts it wants; and in any case it won't |
513 | * block. |
620c146d |
514 | */ |
515 | |
516 | #define ADNS_POLLFDS_RECOMMENDED 2 |
517 | /* If you allocate an fds buf with at least RECOMMENDED entries then |
518 | * you are unlikely to need to enlarge it. You are recommended to do |
519 | * so if it's convenient. However, you must be prepared for adns to |
520 | * require more space than this. |
521 | */ |
522 | |
523 | void adns_afterpoll(adns_state ads, const struct pollfd *fds, int nfds, |
524 | const struct timeval *now); |
525 | /* Gives adns flow-of-control for a bit; intended for use after |
526 | * poll(2). fds and nfds should be the results from poll(). pollfd |
527 | * structs mentioning fds not belonging to adns will be ignored. |
528 | */ |
529 | |
530 | |
86e7b8d9 |
531 | adns_status adns_rr_info(adns_rrtype type, |
532 | const char **rrtname_r, const char **fmtname_r, |
533 | int *len_r, |
534 | const void *datap, char **data_r); |
535 | /* Gets information in human-readable (but non-i18n) form |
536 | * for eg debugging purposes. type must be specified, |
537 | * and the official name of the corresponding RR type will |
538 | * be returned in *rrtname_r, and information about the processing |
539 | * style in *fmtname_r. The length of the table entry in an answer |
540 | * for that type will be returned in in *len_r. |
541 | * Any or all of rrtname_r, fmtname_r and len_r may be 0. |
542 | * If fmtname_r is non-null then *fmtname_r may be |
543 | * null on return, indicating that no special processing is |
544 | * involved. |
545 | * |
546 | * data_r be must be non-null iff datap is. In this case |
547 | * *data_r will be set to point to a human-readable text |
548 | * string representing the RR data. The text will have |
549 | * been obtained from malloc() and must be freed by the caller. |
550 | * |
551 | * Usually this routine will succeed. Possible errors include: |
552 | * adns_s_nomemory |
ea1e31e3 |
553 | * adns_s_rrtypeunknown |
86e7b8d9 |
554 | * adns_s_invaliddata (*datap contained garbage) |
555 | * If an error occurs then no memory has been allocated, |
556 | * and *rrtname_r, *fmtname_r, *len_r and *data_r are undefined. |
557 | */ |
558 | |
31144a72 |
559 | const char *adns_strerror(adns_status st); |
9da4a044 |
560 | const char *adns_errabbrev(adns_status st); |
620c146d |
561 | /* Like strerror but for adns_status values. adns_errabbrev returns |
562 | * the abbreviation of the error - eg, for adns_s_timeout it returns |
563 | * "timeout". You MUST NOT call these functions with status values |
564 | * not returned by the same adns library. |
565 | */ |
31144a72 |
566 | |
a17d3a1d |
567 | #endif |