f3efc943 |
1 | /* |
2 | * adns.h |
3 | * - adns user-visible API (single-threaded, without any locking) |
4 | */ |
5bb95567 |
5 | /* |
3ff64957 |
6 | * This file is part of adns, which is Copyright (C) 1997-1999 Ian Jackson |
98db6da3 |
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, |
3ff64957 |
20 | * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
21 | * |
125de2a9 |
22 | * $Id: adns.h,v 1.55 1999/08/05 00:03:24 ian Exp $ |
5bb95567 |
23 | */ |
5db99a2e |
24 | |
25 | #ifndef ADNS_H_INCLUDED |
26 | #define ADNS_H_INCLUDED |
62049492 |
27 | #ifdef __cplusplus |
28 | extern "C" { /* I really dislike this - iwj. */ |
29 | #endif |
5db99a2e |
30 | |
d05cc330 |
31 | #include <stdio.h> |
32 | |
e7afa27f |
33 | #include <sys/socket.h> |
34 | #include <netinet/in.h> |
125de2a9 |
35 | #include <sys/types.h> |
36 | #include <sys/time.h> |
37 | #include <unistd.h> |
e7afa27f |
38 | |
8c3aa944 |
39 | /* All struct in_addr anywhere in adns are in NETWORK byte order. */ |
40 | |
e7afa27f |
41 | typedef struct adns__state *adns_state; |
42 | typedef struct adns__query *adns_query; |
5db99a2e |
43 | |
44 | typedef enum { |
dfdbb32c |
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 */ |
96e79df5 |
48 | adns_if_debug= 0x0008, /* enable all output to stderr plus debug msgs */ |
dfdbb32c |
49 | adns_if_noautosys= 0x0010, /* do not make syscalls at every opportunity */ |
f318f883 |
50 | adns_if_eintr= 0x0020, /* allow _wait and _synchronous to return EINTR */ |
87e46054 |
51 | adns_if_nosigpipe= 0x0040, /* applic has SIGPIPE set to SIG_IGN, do not protect */ |
5db99a2e |
52 | } adns_initflags; |
53 | |
54 | typedef enum { |
cd363ffd |
55 | adns_qf_search= 0x000001, /* use the searchlist */ |
56 | adns_qf_usevc= 0x000002, /* use a virtual circuit (TCP connection) */ |
b2988d3e |
57 | adns_qf_owner= 0x000004, /* fill in the owner field in the answer */ |
cd363ffd |
58 | adns_qf_quoteok_query= 0x000010, /* allow quote-requiring chars in query domain */ |
59 | adns_qf_quoteok_cname= 0x000020, /* allow ... in CNAME we go via */ |
60 | adns_qf_quoteok_anshost= 0x000040, /* allow ... in answers expected to be hostnames */ |
61 | adns_qf_cname_loose= 0x000100, /* allow refs to CNAMEs - without, get _s_cname */ |
62 | adns_qf_cname_forbid= 0x000200, /* don't follow CNAMEs, instead give _s_cname */ |
63 | adns__qf_internalmask= 0x0ff000 |
5db99a2e |
64 | } adns_queryflags; |
65 | |
66 | typedef enum { |
31d3a9d0 |
67 | adns__rrt_typemask= 0x0ffff, |
96e79df5 |
68 | adns__qtf_deref= 0x10000, /* dereference domains and perhaps produce extra data */ |
69 | adns__qtf_mail822= 0x20000, /* make mailboxes be in RFC822 rcpt field format */ |
96e79df5 |
70 | |
31d3a9d0 |
71 | adns_r_none= 0, |
96e79df5 |
72 | |
31d3a9d0 |
73 | adns_r_a= 1, |
96e79df5 |
74 | |
31d3a9d0 |
75 | adns_r_ns_raw= 2, |
76 | adns_r_ns= adns_r_ns_raw|adns__qtf_deref, |
96e79df5 |
77 | |
31d3a9d0 |
78 | adns_r_cname= 5, |
96e79df5 |
79 | |
31d3a9d0 |
80 | adns_r_soa_raw= 6, |
96e79df5 |
81 | adns_r_soa= adns_r_soa_raw|adns__qtf_mail822, |
96e79df5 |
82 | |
31d3a9d0 |
83 | adns_r_ptr_raw= 12, |
84 | adns_r_ptr= adns_r_ptr_raw|adns__qtf_deref, |
96e79df5 |
85 | |
31d3a9d0 |
86 | adns_r_hinfo= 13, |
96e79df5 |
87 | |
31d3a9d0 |
88 | adns_r_mx_raw= 15, |
89 | adns_r_mx= adns_r_mx_raw|adns__qtf_deref, |
96e79df5 |
90 | |
31d3a9d0 |
91 | adns_r_txt= 16, |
96e79df5 |
92 | |
31d3a9d0 |
93 | adns_r_rp_raw= 17, |
d05cc330 |
94 | adns_r_rp= adns_r_rp_raw|adns__qtf_mail822, |
cd363ffd |
95 | |
96 | adns_r_addr= adns_r_a|adns__qtf_deref |
96e79df5 |
97 | |
5db99a2e |
98 | } adns_rrtype; |
99 | |
c2875680 |
100 | /* In queries without qf_quoteok_*, all domains must have standard |
101 | * legal syntax. In queries _with_ qf_quoteok_*, domains in the query |
102 | * or response may contain any characters, quoted according to RFC1035 |
103 | * 5.1. On input to adns, the char* is a pointer to the interior of a |
104 | * " delimited string, except that " may appear in it, and on output, |
105 | * the char* is a pointer to a string which would be legal either |
106 | * inside or outside " delimiters, and any characters not usually |
107 | * legal in domain names will be quoted as \X (if the character is |
108 | * 33-126 except \ and ") or \DDD. |
e7afa27f |
109 | * |
96e79df5 |
110 | * Do not ask for _raw records containing mailboxes without |
111 | * specifying _qf_anyquote. |
e7afa27f |
112 | */ |
113 | |
5db99a2e |
114 | typedef enum { |
115 | adns_s_ok, |
9b86645c |
116 | |
117 | /* locally induced errors */ |
118 | adns_s_nomemory, |
119 | adns_s_unknownrrtype, |
74c94831 |
120 | adns_s_systemfail, |
121 | |
122 | adns_s_max_localfail= 29, |
9b86645c |
123 | |
124 | /* remotely induced errors, detected locally */ |
dfdbb32c |
125 | adns_s_timeout, |
48cb0b4b |
126 | adns_s_allservfail, |
168e26fe |
127 | adns_s_norecurse, |
9b86645c |
128 | adns_s_invalidresponse, |
129 | adns_s_unknownformat, |
74c94831 |
130 | |
131 | adns_s_max_remotefail= 59, |
9b86645c |
132 | |
133 | /* remotely induced errors, reported by remote server to us */ |
134 | adns_s_rcodeservfail, |
135 | adns_s_rcodeformaterror, |
136 | adns_s_rcodenotimplemented, |
137 | adns_s_rcoderefused, |
138 | adns_s_rcodeunknown, |
74c94831 |
139 | |
54ed1d64 |
140 | adns_s_max_tempfail= 99, |
9b86645c |
141 | |
142 | /* remote configuration errors */ |
143 | adns_s_inconsistent, /* PTR gives domain whose A does not exist and match */ |
144 | adns_s_prohibitedcname, /* CNAME found where eg A expected (not if _qf_loosecname) */ |
145 | adns_s_answerdomaininvalid, |
146 | adns_s_answerdomaintoolong, |
147 | adns_s_invaliddata, |
148 | |
149 | adns_s_max_misconfig= 199, |
150 | |
9b86645c |
151 | /* permanent problems with the query */ |
152 | adns_s_querydomainwrong, |
153 | adns_s_querydomaininvalid, |
154 | adns_s_querydomaintoolong, |
155 | |
156 | adns_s_max_misquery= 299, |
157 | |
158 | /* permanent errors */ |
5db99a2e |
159 | adns_s_nxdomain, |
8312a1c2 |
160 | adns_s_nodata, |
9b86645c |
161 | |
5db99a2e |
162 | } adns_status; |
163 | |
cd363ffd |
164 | typedef struct { |
165 | int len; |
166 | union { |
167 | struct sockaddr sa; |
168 | struct sockaddr_in inet; |
169 | } addr; |
bc01473e |
170 | } adns_rr_addr; |
cd363ffd |
171 | |
6927715a |
172 | typedef struct { |
26eb6bdc |
173 | char *host; |
6927715a |
174 | adns_status astatus; |
175 | int naddrs; /* temp fail => -1, perm fail => 0, s_ok => >0 */ |
bc01473e |
176 | adns_rr_addr *addrs; |
a1d2d0ed |
177 | } adns_rr_hostaddr; |
d05cc330 |
178 | |
179 | typedef struct { |
61093792 |
180 | char *(array[2]); |
d05cc330 |
181 | } adns_rr_strpair; |
182 | |
183 | typedef struct { |
184 | int i; |
26eb6bdc |
185 | adns_rr_hostaddr ha; |
a1d2d0ed |
186 | } adns_rr_inthostaddr; |
d05cc330 |
187 | |
188 | typedef struct { |
f2ad23ee |
189 | /* Used both for mx_raw, in which case i is the preference and str the domain, |
190 | * and for txt, in which case each entry has i for the `text' length, |
191 | * and str for the data (which will have had an extra nul appended |
192 | * so that if it was plain text it is now a null-terminated string). |
193 | */ |
d05cc330 |
194 | int i; |
195 | char *str; |
196 | } adns_rr_intstr; |
197 | |
198 | typedef struct { |
61093792 |
199 | adns_rr_intstr array[2]; |
200 | } adns_rr_intstrpair; |
201 | |
202 | typedef struct { |
203 | char *mname, *rname; |
d05cc330 |
204 | unsigned long serial, refresh, retry, expire, minimum; |
205 | } adns_rr_soa; |
6927715a |
206 | |
5617a135 |
207 | typedef struct { |
5db99a2e |
208 | adns_status status; |
209 | char *cname; /* always NULL if query was for CNAME records */ |
b2988d3e |
210 | char *owner; /* only set if requested in query flags */ |
1e9efa71 |
211 | adns_rrtype type; /* guaranteed to be same as in query */ |
2c7b101b |
212 | time_t expires; /* expiry time, defined only if _s_ok, nxdomain or nodata. NOT TTL! */ |
965c9782 |
213 | int nrrs, rrsz; |
5db99a2e |
214 | union { |
965c9782 |
215 | void *untyped; |
216 | unsigned char *bytes; |
a1d2d0ed |
217 | char *(*str); /* ns_raw, cname, ptr, ptr_raw */ |
218 | adns_rr_intstr *(*manyistr); /* txt (list of strings ends with i=-1, str=0) */ |
bc01473e |
219 | adns_rr_addr *addr; /* addr */ |
a1d2d0ed |
220 | struct in_addr *inaddr; /* a */ |
221 | adns_rr_hostaddr *hostaddr; /* ns */ |
61093792 |
222 | adns_rr_intstrpair *intstrpair; /* hinfo */ |
223 | adns_rr_strpair *strpair; /* rp, rp_raw */ |
a1d2d0ed |
224 | adns_rr_inthostaddr *inthostaddr; /* mx */ |
225 | adns_rr_intstr *intstr; /* mx_raw */ |
226 | adns_rr_soa *soa; /* soa, soa_raw */ |
5db99a2e |
227 | } rrs; |
5617a135 |
228 | } adns_answer; |
5db99a2e |
229 | |
230 | /* Memory management: |
231 | * adns_state and adns_query are actually pointers to malloc'd state; |
232 | * On submission questions are copied, including the owner domain; |
d05cc330 |
233 | * Answers are malloc'd as a single piece of memory; pointers in the |
234 | * answer struct point into further memory in the answer. |
5db99a2e |
235 | * query_io: |
236 | * Must always be non-null pointer; |
237 | * If *query_io is 0 to start with then any query may be returned; |
238 | * If *query_io is !0 adns_query then only that query may be returned. |
9be46d86 |
239 | * If the call is successful, *query_io, *answer_r, and *context_r |
240 | * will all be set. |
5db99a2e |
241 | * Errors: |
74c94831 |
242 | * Return values are 0 or an errno value. |
243 | * |
244 | * For _init, _init_strcfg, _submit and _synchronous, system errors |
245 | * (eg, failure to create sockets, malloc failure, etc.) return errno |
246 | * values. |
247 | * |
248 | * For _wait and _check failures are reported in the answer |
249 | * structure, and only 0, ESRCH or (for _check) EWOULDBLOCK is |
250 | * returned: if no (appropriate) requests are done adns_check returns |
251 | * EWOULDBLOCK; if no (appropriate) requests are outstanding both |
252 | * adns_query and adns_wait return ESRCH. |
253 | * |
254 | * Additionally, _wait can return EINTR if you set adns_if_eintr. |
255 | * |
256 | * All other errors (nameserver failure, timed out connections, &c) |
257 | * are returned in the status field of the answer. After a |
258 | * successful _wait or _check, if status is nonzero then nrrs will be |
259 | * 0, otherwise it will be >0. type will always be the type |
260 | * requested. |
5db99a2e |
261 | */ |
262 | |
d6b271ae |
263 | int adns_init(adns_state *newstate_r, adns_initflags flags, |
264 | FILE *diagfile /*0=>stderr*/); |
265 | |
266 | int adns_init_strcfg(adns_state *newstate_r, adns_initflags flags, |
267 | FILE *diagfile /*0=>discard*/, const char *configtext); |
5db99a2e |
268 | |
269 | int adns_synchronous(adns_state ads, |
270 | const char *owner, |
271 | adns_rrtype type, |
ebd44fbe |
272 | adns_queryflags flags, |
9ab4dfce |
273 | adns_answer **answer_r); |
5617a135 |
274 | |
275 | /* NB: if you set adns_if_noautosys then _submit and _check do not |
74c94831 |
276 | * make any system calls; you must use some of the asynch-io event |
277 | * processing functions to actually get things to happen. |
5617a135 |
278 | */ |
5db99a2e |
279 | |
280 | int adns_submit(adns_state ads, |
281 | const char *owner, |
282 | adns_rrtype type, |
ebd44fbe |
283 | adns_queryflags flags, |
5db99a2e |
284 | void *context, |
e7afa27f |
285 | adns_query *query_r); |
5db99a2e |
286 | |
e7afa27f |
287 | int adns_check(adns_state ads, |
5db99a2e |
288 | adns_query *query_io, |
9ab4dfce |
289 | adns_answer **answer_r, |
290 | void **context_r); |
5db99a2e |
291 | |
292 | int adns_wait(adns_state ads, |
293 | adns_query *query_io, |
9ab4dfce |
294 | adns_answer **answer_r, |
295 | void **context_r); |
5db99a2e |
296 | |
11c8bf9b |
297 | void adns_cancel(adns_query query); |
5db99a2e |
298 | |
74c94831 |
299 | /* The adns_query you get back from _submit is valid (ie, can be |
300 | * legitimately passed into adns functions) until it is returned by |
301 | * adns_check or adns_wait, or passed to adns_cancel. After that it |
302 | * must not be used. You can rely on it not being reused until the |
303 | * first adns_submit or _transact call using the same adns_state after |
304 | * it became invalid, so you may compare it for equality with other |
305 | * query handles until you next call _query or _transact. |
125de2a9 |
306 | * |
307 | * _submit and _synchronous return ENOSYS if they don't understand the |
308 | * query type. |
74c94831 |
309 | */ |
310 | |
311 | void adns_finish(adns_state ads); |
98db6da3 |
312 | /* You may call this even if you have queries outstanding; |
313 | * they will be cancelled. |
314 | */ |
5db99a2e |
315 | |
e7afa27f |
316 | |
23dca174 |
317 | void adns_forallqueries_begin(adns_state ads); |
8f2aa812 |
318 | adns_query adns_forallqueries_next(adns_state ads, void **context_r); |
74c94831 |
319 | /* Iterator functions, which you can use to loop over the outstanding |
23dca174 |
320 | * (submitted but not yet successfuly checked/waited) queries. |
74c94831 |
321 | * |
23dca174 |
322 | * You can only have one iteration going at once. You may call _begin |
323 | * at any time; after that, an iteration will be in progress. You may |
324 | * only call _next when an iteration is in progress - anything else |
325 | * may coredump. The iteration remains in progress until _next |
326 | * returns 0, indicating that all the queries have been walked over, |
327 | * or ANY other adns function is called with the same adns_state (or a |
328 | * query in the same adns_state). There is no need to explicitly |
329 | * finish an iteration. |
330 | * |
8f2aa812 |
331 | * context_r may be 0. *context_r may not be set when _next returns 0. |
e7afa27f |
332 | */ |
5db99a2e |
333 | |
74c94831 |
334 | /* |
335 | * Example expected/legal calling sequence for submit/check/wait: |
5db99a2e |
336 | * adns_init |
337 | * adns_submit 1 |
338 | * adns_submit 2 |
339 | * adns_submit 3 |
340 | * adns_wait 1 |
e7afa27f |
341 | * adns_check 3 -> EWOULDBLOCK |
5db99a2e |
342 | * adns_wait 2 |
343 | * adns_wait 3 |
344 | * .... |
345 | * adns_finish |
74c94831 |
346 | */ |
347 | |
348 | /* |
349 | * Entrypoints for generic asynch io: |
350 | * (these entrypoints are not very useful except in combination with * |
351 | * some of the other I/O model calls which can tell you which fds to |
352 | * be interested in): |
353 | * |
354 | * Note that any adns call may cause adns to open and close fds, so |
355 | * you must call beforeselect or beforepoll again just before |
356 | * blocking, or you may not have an up-to-date list of it's fds. |
357 | */ |
358 | |
359 | int adns_processany(adns_state ads); |
360 | /* Gives adns flow-of-control for a bit. This will never block, and |
361 | * can be used with any threading/asynch-io model. If some error |
362 | * occurred which might cause an event loop to spin then the errno |
363 | * value is returned. |
364 | */ |
365 | |
366 | int adns_processreadable(adns_state ads, int fd, const struct timeval *now); |
367 | int adns_processwriteable(adns_state ads, int fd, const struct timeval *now); |
368 | int adns_processexceptional(adns_state ads, int fd, const struct timeval *now); |
369 | /* Gives adns flow-of-control so that it can process incoming data |
370 | * from, or send outgoing data via, fd. Very like _processany. If it |
371 | * returns zero then fd will no longer be readable or writeable |
372 | * (unless of course more data has arrived since). adns will _only_ |
373 | * that fd and only in the manner specified, regardless of whether |
374 | * adns_if_noautosys was specified. |
375 | * |
376 | * adns_processexceptional should be called when select(2) reports an |
377 | * exceptional condition, or poll(2) reports POLLPRI. |
378 | * |
379 | * It is fine to call _processreabable or _processwriteable when the |
380 | * fd is not ready, or with an fd that doesn't belong to adns; it will |
381 | * then just return 0. |
382 | * |
383 | * If some error occurred which might prevent an event loop to spin |
384 | * then the errno value is returned. |
385 | */ |
386 | |
387 | void adns_processtimeouts(adns_state ads, const struct timeval *now); |
388 | /* Gives adns flow-of-control so that it can process any timeouts |
389 | * which might have happened. Very like _processreadable/writeable. |
390 | * |
391 | * now may be 0; if it isn't, *now must be the current time, recently |
392 | * obtained from gettimeofday. |
393 | */ |
394 | |
395 | void adns_firsttimeout(adns_state ads, |
396 | struct timeval **tv_mod, struct timeval *tv_buf, |
397 | struct timeval now); |
398 | /* Asks adns when it would first like the opportunity to time |
399 | * something out. now must be the current time, from gettimeofday. |
400 | * |
401 | * If tv_mod points to 0 then tv_buf must be non-null, and |
402 | * _firsttimeout will fill in *tv_buf with the time until the first |
403 | * timeout, and make *tv_mod point to tv_buf. If adns doesn't have |
404 | * anything that might need timing out it will leave *tv_mod as 0. |
405 | * |
406 | * If *tv_mod is not 0 then tv_buf is not used. adns will update |
407 | * *tv_mod if it has any earlier timeout, and leave it alone if it |
408 | * doesn't. |
409 | * |
410 | * This call will not actually do any I/O, or change the fds that adns |
411 | * is using. It always succeeds and never blocks. |
412 | */ |
413 | |
414 | void adns_globalsystemfailure(adns_state ads); |
415 | /* If serious problem(s) happen which globally affect your ability to |
416 | * interact properly with adns, or adns's ability to function |
417 | * properly, you or adns can call this function. |
418 | * |
419 | * All currently outstanding queries will be made to fail with |
420 | * adns_s_systemfail, and adns will close any stream sockets it has |
421 | * open. |
422 | * |
423 | * This is used by adns, for example, if gettimeofday() fails. |
424 | * Without this the program's event loop might start to spin ! |
425 | * |
426 | * This call will never block. |
427 | */ |
428 | |
429 | /* |
430 | * Entrypoints for select-loop based asynch io: |
431 | */ |
432 | |
433 | void adns_beforeselect(adns_state ads, int *maxfd, fd_set *readfds, |
434 | fd_set *writefds, fd_set *exceptfds, |
435 | struct timeval **tv_mod, struct timeval *tv_buf, |
436 | const struct timeval *now); |
437 | /* Find out file descriptors adns is interested in, and when it would |
438 | * like the opportunity to time something out. If you do not plan to |
439 | * block then tv_mod may be 0. Otherwise, tv_mod and tv_buf are as |
440 | * for adns_firsttimeout. readfds, writefds, exceptfds and maxfd_io may |
441 | * not be 0. |
442 | * |
443 | * If *now is not 0 then this will never actually do any I/O, or |
444 | * change the fds that adns is using or the timeouts it wants. In any |
445 | * case it won't block. |
446 | */ |
447 | |
448 | void adns_afterselect(adns_state ads, int maxfd, const fd_set *readfds, |
449 | const fd_set *writefds, const fd_set *exceptfds, |
450 | const struct timeval *now); |
451 | /* Gives adns flow-of-control for a bit; intended for use after |
452 | * select. This is just a fancy way of calling adns_processreadable/ |
453 | * writeable/timeouts as appropriate, as if select had returned the |
454 | * data being passed. Always succeeds. |
455 | */ |
456 | |
457 | /* |
458 | * Example calling sequence: |
5db99a2e |
459 | * |
5617a135 |
460 | * adns_init _noautosys |
5db99a2e |
461 | * loop { |
74c94831 |
462 | * adns_beforeselect |
5db99a2e |
463 | * select |
74c94831 |
464 | * adns_afterselect |
5617a135 |
465 | * ... |
466 | * adns_submit / adns_check |
467 | * ... |
5db99a2e |
468 | * } |
469 | */ |
470 | |
74c94831 |
471 | /* |
472 | * Entrypoints for poll-loop based asynch io: |
473 | */ |
474 | |
475 | struct pollfd; |
476 | /* In case your system doesn't have it or you forgot to include |
477 | * <sys/poll.h>, to stop the following declarations from causing |
478 | * problems. If your system doesn't have poll then the following |
479 | * entrypoints will not be defined in libadns. Sorry ! |
480 | */ |
481 | |
482 | int adns_beforepoll(adns_state ads, struct pollfd *fds, int *nfds_io, int *timeout_io, |
483 | const struct timeval *now); |
484 | /* Finds out which fd's adns is interested in, and when it would like |
485 | * to be able to time things out. This is in a form suitable for use |
486 | * with poll(2). |
487 | * |
488 | * On entry, usually fds should point to at least *nfds_io structs. |
489 | * adns will fill up to that many structs will information for poll, |
490 | * and record in *nfds_io how many structs it filled. If it wants to |
491 | * listen for more structs then *nfds_io will be set to the number |
492 | * required and _beforepoll will return ERANGE. |
493 | * |
74c94831 |
494 | * You may call _beforepoll with fds==0 and *nfds_io 0, in which case |
495 | * adns will fill in the number of fds that it might be interested in |
4f973eb5 |
496 | * in *nfds_io, and always return either 0 (if it is not interested in |
497 | * any fds) or ERANGE (if it is). |
498 | * |
499 | * NOTE that (unless timeout_io is 0) adns may acquire additional fds |
500 | * from one call to the next, so you must put adns_beforepoll in a |
501 | * loop, rather than assuming that the second call (with the buffer |
502 | * size requested by the first) will not return ERANGE. |
74c94831 |
503 | * |
504 | * adns only ever sets POLLIN, POLLOUT and POLLPRI in its pollfd |
505 | * structs, and only ever looks at those bits. POLLPRI is required to |
4f973eb5 |
506 | * detect TCP Urgent Data (which should not be used by a DNS server) |
74c94831 |
507 | * so that adns can know that the TCP stream is now useless. |
508 | * |
509 | * In any case, *timeout_io should be a timeout value as for poll(2), |
510 | * which adns will modify downwards as required. If the caller does |
4f973eb5 |
511 | * not plan to block then *timeout_io should be 0 on entry, or |
512 | * alternatively, timeout_io may be 0. (Alternatively, the caller may |
513 | * use _beforeselect with timeout_io==0 to find out about file |
514 | * descriptors, and use _firsttimeout is used to find out when adns |
515 | * might want to time something out.) |
74c94831 |
516 | * |
517 | * adns_beforepoll will return 0 on success, and will not fail for any |
518 | * reason other than the fds buffer being too small (ERANGE). |
519 | * |
4f973eb5 |
520 | * This call will never actually do any I/O, or change the fds that |
521 | * adns is using or the timeouts it wants; and in any case it won't |
522 | * block. |
74c94831 |
523 | */ |
524 | |
525 | #define ADNS_POLLFDS_RECOMMENDED 2 |
526 | /* If you allocate an fds buf with at least RECOMMENDED entries then |
527 | * you are unlikely to need to enlarge it. You are recommended to do |
528 | * so if it's convenient. However, you must be prepared for adns to |
529 | * require more space than this. |
530 | */ |
531 | |
532 | void adns_afterpoll(adns_state ads, const struct pollfd *fds, int nfds, |
533 | const struct timeval *now); |
534 | /* Gives adns flow-of-control for a bit; intended for use after |
535 | * poll(2). fds and nfds should be the results from poll(). pollfd |
536 | * structs mentioning fds not belonging to adns will be ignored. |
537 | */ |
538 | |
539 | |
1e9efa71 |
540 | adns_status adns_rr_info(adns_rrtype type, |
541 | const char **rrtname_r, const char **fmtname_r, |
542 | int *len_r, |
543 | const void *datap, char **data_r); |
544 | /* Gets information in human-readable (but non-i18n) form |
545 | * for eg debugging purposes. type must be specified, |
546 | * and the official name of the corresponding RR type will |
547 | * be returned in *rrtname_r, and information about the processing |
548 | * style in *fmtname_r. The length of the table entry in an answer |
549 | * for that type will be returned in in *len_r. |
550 | * Any or all of rrtname_r, fmtname_r and len_r may be 0. |
551 | * If fmtname_r is non-null then *fmtname_r may be |
552 | * null on return, indicating that no special processing is |
553 | * involved. |
554 | * |
555 | * data_r be must be non-null iff datap is. In this case |
556 | * *data_r will be set to point to a human-readable text |
557 | * string representing the RR data. The text will have |
558 | * been obtained from malloc() and must be freed by the caller. |
559 | * |
560 | * Usually this routine will succeed. Possible errors include: |
561 | * adns_s_nomemory |
9b86645c |
562 | * adns_s_rrtypeunknown |
1e9efa71 |
563 | * adns_s_invaliddata (*datap contained garbage) |
564 | * If an error occurs then no memory has been allocated, |
565 | * and *rrtname_r, *fmtname_r, *len_r and *data_r are undefined. |
566 | */ |
567 | |
7f702335 |
568 | const char *adns_strerror(adns_status st); |
c2875680 |
569 | const char *adns_errabbrev(adns_status st); |
74c94831 |
570 | /* Like strerror but for adns_status values. adns_errabbrev returns |
571 | * the abbreviation of the error - eg, for adns_s_timeout it returns |
572 | * "timeout". You MUST NOT call these functions with status values |
573 | * not returned by the same adns library. |
574 | */ |
7f702335 |
575 | |
62049492 |
576 | #ifdef __cplusplus |
577 | } /* end of extern "C" */ |
578 | #endif |
5db99a2e |
579 | #endif |