3 * - adns user-visible API
7 * This file is part of adns, which is
8 * Copyright (C) 1997-2000,2003,2006,2014-2016 Ian Jackson
9 * Copyright (C) 1999-2000,2003,2006 Tony Finch
10 * Copyright (C) 1991 Massachusetts Institute of Technology
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License as published by
14 * the Free Software Foundation; either version 3, or (at your option)
17 * This program is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 * GNU General Public License for more details.
23 * For the benefit of certain LGPL'd `omnibus' software which
24 * provides a uniform interface to various things including adns, I
25 * make the following additional licence. I do this because the GPL
26 * would otherwise force either the omnibus software to be GPL'd or
27 * the adns-using part to be distributed separately.
29 * So: you may also redistribute and/or modify adns.h (but only the
30 * public header file adns.h and not any other part of adns) under the
31 * terms of the GNU Library General Public License as published by the
32 * Free Software Foundation; either version 2 of the License, or (at
33 * your option) any later version.
35 * Note that adns itself is GPL'd. Authors of adns-using applications
36 * with GPL-incompatible licences, and people who distribute adns with
37 * applications where the whole distribution is not GPL'd, are still
38 * likely to be in violation of the GPL. Anyone who wants to do this
39 * should contact Ian Jackson. Please note that to avoid encouraging
40 * people to infringe the GPL as it applies to the body of adns, Ian
41 * thinks that if you take advantage of the special exception to
42 * redistribute just adns.h under the LGPL, you should retain this
43 * paragraph in its place in the appropriate copyright statements.
46 * You should have received a copy of the GNU General Public License,
47 * or the GNU Library General Public License, as appropriate, along
48 * with this program; if not, write to the Free Software Foundation.
52 #ifndef ADNS_H_INCLUDED
53 #define ADNS_H_INCLUDED
58 #include <sys/types.h>
59 #include <sys/socket.h>
60 #include <netinet/in.h>
66 extern "C" { /* I really dislike this - iwj. */
69 /* Whether to support address families other than IPv4 in responses which use
70 * the `adns_rr_addr' structure. This is a source-compatibility issue: old
71 * clients may not expect to find address families other than AF_INET in
72 * their query results. There's a separate binary compatibility issue to do
73 * with the size of the `adns_rr_addr' structure, but we'll assume you can
74 * cope with that because you have this header file. Define
75 * `ADNS_FEATURE_IPV4ONLY' if you only want to see AF_INET addresses by
76 * default, or `ADNS_FEATURE_MANYAF' to allow multiple address families; the
77 * default is currently to stick with AF_INET only, but this is likely to
78 * change in a later release of ADNS. Note that any adns_qf_want_... flags
79 * in your query are observed: this setting affects only the default address
82 #if !defined(ADNS_FEATURE_IPV4ONLY) && !defined(ADNS_FEATURE_MANYAF)
83 # define ADNS_FEATURE_IPV4ONLY
84 #elif defined(ADNS_FEATURE_IPV4ONLY) && defined(ADNS_FEATURE_MANYAF)
85 # error "Feature flags ADNS_FEATURE_IPV4ONLY and ..._MANYAF are incompatible"
88 /* All struct in_addr anywhere in adns are in NETWORK byte order. */
90 typedef struct adns__state *adns_state;
91 typedef struct adns__query *adns_query;
93 typedef enum { /* In general, or together the desired flags: */
94 adns_if_none= 0x0000,/* no flags. nicer than 0 for some compilers */
95 adns_if_noenv= 0x0001,/* do not look at environment */
96 adns_if_noerrprint= 0x0002,/* never print to stderr (_debug overrides) */
97 adns_if_noserverwarn=0x0004,/* do not warn to stderr about duff servers etc */
98 adns_if_debug= 0x0008,/* enable all output to stderr plus debug msgs */
99 adns_if_logpid= 0x0080,/* include pid in diagnostic output */
100 adns_if_noautosys= 0x0010,/* do not make syscalls at every opportunity */
101 adns_if_eintr= 0x0020,/* allow _wait and _synchronous to return EINTR */
102 adns_if_nosigpipe= 0x0040,/* applic has SIGPIPE ignored, do not protect */
103 adns_if_checkc_entex=0x0100,/* consistency checks on entry/exit to adns fns */
104 adns_if_checkc_freq= 0x0300,/* consistency checks very frequently (slow!) */
106 adns_if_permit_ipv4= 0x0400,/* allow _addr queries to return IPv4 addresses */
107 adns_if_permit_ipv6= 0x0800,/* allow _addr queries to return IPv6 addresses */
108 adns_if_afmask= 0x0c00,
109 /* These are policy flags, and overridden by the adns_af:... option in
110 * resolv.conf. If the adns_qf_want_... query flags are incompatible with
111 * these settings (in the sense that no address families are permitted at
112 * all) then the query flags take precedence; otherwise only records which
113 * satisfy all of the stated requirements are allowed.
115 adns__if_sizeforce= 0x7fff,
118 typedef enum { /* In general, or together the desired flags: */
119 adns_qf_none= 0x00000000,/* no flags */
120 adns_qf_search= 0x00000001,/* use the searchlist */
121 adns_qf_usevc= 0x00000002,/* use a virtual circuit (TCP conn) */
122 adns_qf_owner= 0x00000004,/* fill in the owner field in the answer */
123 adns_qf_quoteok_query= 0x00000010,/* allow special chars in query domain */
124 adns_qf_quoteok_cname= 0x00000000,/* ... in CNAME we go via (now default) */
125 adns_qf_quoteok_anshost=0x00000040,/* ... in things supposedly hostnames */
126 adns_qf_quotefail_cname=0x00000080,/* refuse if quote-req chars in CNAME we go via */
127 adns_qf_cname_loose= 0x00000100,/* allow refs to CNAMEs - without, get _s_cname */
128 adns_qf_cname_strict= 0x00010000,/* forbid CNAME refs (default, currently) */
129 adns_qf_cname_forbid= 0x00000200,/* don't follow CNAMEs, instead give _s_cname */
131 adns_qf_want_ipv4= 0x00000400,/* try to return IPv4 addresses */
132 adns_qf_want_ipv6= 0x00000800,/* try to return IPv6 addresses */
133 adns_qf_want_allaf= 0x00000c00,/* all the above flag bits */
134 /* Without any of the _qf_want_... flags, _qtf_deref queries try to return
135 * all address families permitted by _if_permit_... (as overridden by the
136 * `adns_af:...' configuration option). Set flags to restrict the
137 * returned address families to the ones selected.
139 adns_qf_ipv6_mapv4= 0x00001000,/* ... return IPv4 addresses as v6-mapped */
141 adns_qf_addrlit_scope_forbid=0x00002000,/* forbid %<scope> in IPv6 literals */
142 adns_qf_addrlit_scope_numeric=0x00004000,/* %<scope> may only be numeric */
143 adns_qf_addrlit_ipv4_quadonly=0x00008000,/* reject non-dotted-quad ipv4 */
145 adns__qf_internalmask= 0x0ff00000,
146 adns__qf_sizeforce= 0x7fffffff
150 adns_rrt_typemask= 0x0ffff,
151 adns_rrt_reprmask= 0xffffff,
152 adns__qtf_deref_bit=0x10000,/* internal version of ..._deref below */
153 adns__qtf_mail822= 0x20000,/* return mailboxes in RFC822 rcpt field fmt */
155 adns__qtf_bigaddr=0x1000000,/* use the new larger sockaddr union */
156 adns__qtf_manyaf= 0x2000000,/* permitted to return multiple address families */
158 adns__qtf_deref= adns__qtf_deref_bit|adns__qtf_bigaddr
159 #ifdef ADNS_FEATURE_MANYAF
162 ,/* dereference domains; perhaps get extra data */
164 adns_r_unknown= 0x40000,
165 /* To use this, ask for records of type <rr-type-code>|adns_r_unknown.
166 * adns will not process the RDATA - you'll get adns_rr_byteblocks,
167 * where the int is the length and the unsigned char* points to the
168 * data. String representation of the RR data (by adns_rrinfo) is as in
169 * RFC3597. adns_rr_info will not return the type name in *rrtname_r
170 * (due to memory management problems); *fmtname_r will be set to
173 * Do not specify adns_r_unknown along with a known RR type which
174 * requires domain name uncompression (see RFC3597 s4); domain names
175 * will not be uncompressed and the resulting data would be useless.
176 * Asking for meta-RR types via adns_r_unknown will not work properly
177 * either and may make adns complain about server misbehaviour, so don't
180 * Don't forget adns_qf_quoteok if that's what you want. */
187 adns_r_ns= adns_r_ns_raw|adns__qtf_deref,
192 adns_r_soa= adns_r_soa_raw|adns__qtf_mail822,
194 adns_r_ptr_raw= 12, /* do not mind PTR with wrong or missing addr */
195 adns_r_ptr= adns_r_ptr_raw|adns__qtf_deref,
200 adns_r_mx= adns_r_mx_raw|adns__qtf_deref,
205 adns_r_rp= adns_r_rp_raw|adns__qtf_mail822,
209 /* For SRV records, query domain without _qf_quoteok_query must look
210 * as expected from SRV RFC with hostname-like Name. _With_
211 * _quoteok_query, any query domain is allowed. */
213 adns_r_srv= adns_r_srv_raw|adns__qtf_deref,
215 adns_r_addr= adns_r_a|adns__qtf_deref,
217 adns__rrt_sizeforce= 0x7fffffff,
222 * In queries without qf_quoteok_*, all domains must have standard
223 * legal syntax, or you get adns_s_querydomainvalid (if the query
224 * domain contains bad characters) or adns_s_answerdomaininvalid (if
225 * the answer contains bad characters).
227 * In queries _with_ qf_quoteok_*, domains in the query or response
228 * may contain any characters, quoted according to RFC1035 5.1. On
229 * input to adns, the char* is a pointer to the interior of a "
230 * delimited string, except that " may appear in it unquoted. On
231 * output, the char* is a pointer to a string which would be legal
232 * either inside or outside " delimiters; any character which isn't
233 * legal in a hostname (ie alphanumeric or hyphen) or one of _ / +
234 * (the three other punctuation characters commonly abused in domain
235 * names) will be quoted, as \X if it is a printing ASCII character or
238 * If the query goes via a CNAME then the canonical name (ie, the
239 * thing that the CNAME record refers to) is usually allowed to
240 * contain any characters, which will be quoted as above. With
241 * adns_qf_quotefail_cname you get adns_s_answerdomaininvalid when
242 * this happens. (This is a change from version 0.4 and earlier, in
243 * which failing the query was the default, and you had to say
244 * adns_qf_quoteok_cname to avoid this; that flag is now deprecated.)
246 * In version 0.4 and earlier, asking for _raw records containing
247 * mailboxes without specifying _qf_quoteok_anshost was silly. This
248 * is no longer the case. In this version only parts of responses
249 * that are actually supposed to be hostnames will be refused by
250 * default if quote-requiring characters are found.
254 * If you ask for an RR which contains domains which are actually
255 * encoded mailboxes, and don't ask for the _raw version, then adns
256 * returns the mailbox formatted suitably for an RFC822 recipient
257 * header field. The particular format used is that if the mailbox
258 * requires quoting according to the rules in RFC822 then the
259 * local-part is quoted in double quotes, which end at the next
260 * unescaped double quote (\ is the escape char, and is doubled, and
261 * is used to escape only \ and "). If the local-part is legal
262 * without quoting according to RFC822, it is presented as-is. In any
263 * case the local-part is followed by an @ and the domain. The domain
264 * will not contain any characters not legal in hostnames.
266 * Unquoted local-parts may contain any printing 7-bit ASCII
267 * except the punctuation characters ( ) < > @ , ; : \ " [ ]
268 * I.e. they may contain alphanumerics, and the following
269 * punctuation characters: ! # % ^ & * - _ = + { } .
271 * adns will reject local parts containing control characters (byte
272 * values 0-31, 127-159, and 255) - these appear to be legal according
273 * to RFC822 (at least 0-127) but are clearly a bad idea. RFC1035
274 * syntax does not make any distinction between a single RFC822
275 * quoted-string containing full stops, and a series of quoted-strings
276 * separated by full stops; adns will return anything that isn't all
277 * valid atoms as a single quoted-string. RFC822 does not allow
278 * high-bit-set characters at all, but adns does allow them in
279 * local-parts, treating them as needing quoting.
281 * If you ask for the domain with _raw then _no_ checking is done
282 * (even on the host part, regardless of adns_qf_quoteok_anshost), and
283 * you just get the domain name in master file format.
285 * If no mailbox is supplied the returned string will be `.' in either
292 /* locally induced errors */
294 adns_s_unknownrrtype,
297 adns_s_max_localfail= 29,
299 /* remotely induced errors, detected locally */
303 adns_s_invalidresponse,
304 adns_s_unknownformat,
306 adns_s_max_remotefail= 59,
308 /* remotely induced errors, reported by remote server to us */
309 adns_s_rcodeservfail,
310 adns_s_rcodeformaterror,
311 adns_s_rcodenotimplemented,
315 adns_s_max_tempfail= 99,
317 /* remote configuration errors */
318 adns_s_inconsistent, /* PTR gives domain whose addr is missing or mismatch */
319 adns_s_prohibitedcname, /* CNAME, but eg A expected (not if _qf_cname_loose) */
320 adns_s_answerdomaininvalid,
321 adns_s_answerdomaintoolong,
324 adns_s_max_misconfig= 199,
326 /* permanent problems with the query */
327 adns_s_querydomainwrong,
328 adns_s_querydomaininvalid,
329 adns_s_querydomaintoolong,
331 adns_s_max_misquery= 299,
333 /* permanent errors */
337 adns_s_max_permfail= 499
343 struct sockaddr_in inet;
344 } adns_sockaddr_v4only;
348 struct sockaddr_in inet;
349 struct sockaddr_in6 inet6;
358 /* the old v4-only structure; handy if you have complicated binary
359 * compatibility problems. */
361 adns_sockaddr_v4only addr;
362 } adns_rr_addr_v4only;
367 int naddrs; /* temp fail => -1, perm fail => 0, s_ok => >0 */
378 } adns_rr_inthostaddr;
381 /* Used both for mx_raw, in which case i is the preference and str
382 * the domain, and for txt, in which case each entry has i for the
383 * `text' length, and str for the data (which will have had an extra
384 * nul appended so that if it was plain text it is now a
385 * null-terminated string).
392 adns_rr_intstr array[2];
393 } adns_rr_intstrpair;
397 unsigned long serial, refresh, retry, expire, minimum;
401 int priority, weight, port;
406 int priority, weight, port;
417 char *cname; /* always NULL if query was for CNAME records */
418 char *owner; /* only set if req'd in query flags; maybe 0 on error anyway */
419 adns_rrtype type; /* guaranteed to be same as in query */
420 time_t expires;/*abs time. def only if _s_ok, nxdomain or nodata. NOT TTL!*/
421 int nrrs, rrsz; /* nrrs is 0 if an error occurs */
424 unsigned char *bytes;
425 char *(*str); /* ns_raw, cname, ptr, ptr_raw */
426 adns_rr_intstr *(*manyistr); /* txt (list strs ends with i=-1, str=0)*/
427 adns_rr_addr *addr; /* addr */
428 struct in_addr *inaddr; /* a */
429 struct in6_addr *in6addr; /* aaaa */
430 adns_rr_hostaddr *hostaddr; /* ns */
431 adns_rr_intstrpair *intstrpair; /* hinfo */
432 adns_rr_strpair *strpair; /* rp, rp_raw */
433 adns_rr_inthostaddr *inthostaddr;/* mx */
434 adns_rr_intstr *intstr; /* mx_raw */
435 adns_rr_soa *soa; /* soa, soa_raw */
436 adns_rr_srvraw *srvraw; /* srv_raw */
437 adns_rr_srvha *srvha;/* srv */
438 adns_rr_byteblock *byteblock; /* ...|unknown */
442 /* Memory management:
443 * adns_state and adns_query are actually pointers to malloc'd state;
444 * On submission questions are copied, including the owner domain;
445 * Answers are malloc'd as a single piece of memory; pointers in the
446 * answer struct point into further memory in the answer.
448 * Must always be non-null pointer;
449 * If *query_io is 0 to start with then any query may be returned;
450 * If *query_io is !0 adns_query then only that query may be returned.
451 * If the call is successful, *query_io, *answer_r, and *context_r
454 * Return values are 0 or an errno value.
456 * For _init, _init_strcfg, _submit and _synchronous, system errors
457 * (eg, failure to create sockets, malloc failure, etc.) return errno
458 * values. EINVAL from _init et al means the configuration file
459 * is erroneous and cannot be parsed.
461 * For _wait and _check failures are reported in the answer
462 * structure, and only 0, ESRCH or (for _check) EAGAIN is
463 * returned: if no (appropriate) requests are done adns_check returns
464 * EAGAIN; if no (appropriate) requests are outstanding both
465 * adns_query and adns_wait return ESRCH.
467 * Additionally, _wait can return EINTR if you set adns_if_eintr.
469 * All other errors (nameserver failure, timed out connections, &c)
470 * are returned in the status field of the answer. After a
471 * successful _wait or _check, if status is nonzero then nrrs will be
472 * 0, otherwise it will be >0. type will always be the type
477 * adns does not use any static modifiable state, so it
478 * is safe to call adns_init several times and then use the
479 * resulting adns_states concurrently.
480 * However, it is NOT safe to make simultaneous calls into
481 * adns using the same adns_state; a single adns_state must be used
482 * only by one thread at a time. You can solve this problem by
483 * having one adns_state per thread, or if that isn't feasible, you
484 * could maintain a pool of adns_states. Unfortunately neither of
485 * these approaches has optimal performance.
488 int adns_init(adns_state *newstate_r, adns_initflags flags,
489 FILE *diagfile /*0=>stderr*/);
491 int adns_init_strcfg(adns_state *newstate_r, adns_initflags flags,
492 FILE *diagfile /*0=>discard*/, const char *configtext);
494 typedef void adns_logcallbackfn(adns_state ads, void *logfndata,
495 const char *fmt, va_list al);
496 /* Will be called perhaps several times for each message; when the
497 * message is complete, the string implied by fmt and al will end in
498 * a newline. Log messages start with `adns debug:' or `adns
499 * warning:' or `adns:' (for errors), or `adns debug [PID]:'
500 * etc. if adns_if_logpid is set. */
502 int adns_init_logfn(adns_state *newstate_r, adns_initflags flags,
503 const char *configtext /*0=>use default config files*/,
504 adns_logcallbackfn *logfn /*0=>logfndata is a FILE* */,
505 void *logfndata /*0 with logfn==0 => discard*/);
508 * adns_init reads /etc/resolv.conf, which is expected to be (broadly
509 * speaking) in the format expected by libresolv, and then
510 * /etc/resolv-adns.conf if it exists. adns_init_strcfg is instead
511 * passed a string which is interpreted as if it were the contents of
512 * resolv.conf or resolv-adns.conf. In general, configuration which
513 * is set later overrides any that is set earlier.
515 * Standard directives understood in resolv[-adns].conf:
517 * nameserver <address>
518 * Must be followed by the IP address of a nameserver. Several
519 * nameservers may be specified, and they will be tried in the order
520 * found. There is a compiled in limit, currently 5, on the number
521 * of nameservers. (libresolv supports only 3 nameservers.)
523 * search <domain> ...
524 * Specifies the search list for queries which specify
525 * adns_qf_search. This is a list of domains to append to the query
526 * domain. The query domain will be tried as-is either before all
527 * of these or after them, depending on the ndots option setting
531 * This is present only for backward compatibility with obsolete
532 * versions of libresolv. It should not be used, and is interpreted
533 * by adns as if it were `search' - note that this is subtly
534 * different to libresolv's interpretation of this directive.
536 * sortlist <addr>/<mask> ...
537 * Should be followed by a sequence of IP-address and netmask pairs,
538 * separated by spaces. They may be specified as
539 * eg. 172.30.206.0/24 or 172.30.206.0/255.255.255.0. Currently up
540 * to 15 pairs may be specified (but note that libresolv only
541 * supports up to 10).
544 * Should followed by one or more options, separated by spaces.
545 * Each option consists of an option name, followed by optionally
546 * a colon and a value. Options are listed below.
548 * Non-standard directives understood in resolv[-adns].conf:
551 * Clears the list of nameservers, so that further nameserver lines
552 * start again from the beginning.
555 * The specified file will be read.
557 * Additionally, adns will ignore lines in resolv[-adns].conf which
560 * Standard options understood:
563 * Enables debugging output from the resolver, which will be written
567 * Affects whether queries with adns_qf_search will be tried first
568 * without adding domains from the searchlist, or whether the bare
569 * query domain will be tried last. Queries which contain at least
570 * <count> dots will be tried bare first. The default is 1.
572 * Non-standard options understood:
577 * Changes the consistency checking frequency; this overrides the
578 * setting of adns_if_check_entex, adns_if_check_freq, or neither,
579 * in the flags passed to adns_init.
581 * adns_af:{ipv4,ipv6},... adns_af:any
582 * Determines which address families ADNS looks up (either as an
583 * adns_r_addr query, or when dereferencing an answer yielding hostnames
584 * (e.g., adns_r_mx). The argument is a comma-separated list: only the
585 * address families listed will be looked up. The default is `any'.
586 * Lookups occur (logically) concurrently; use the `sortlist' directive to
587 * control the relative order of addresses in answers. This option
588 * overrides the corresponding init flags (covered by adns_if_afmask).
591 * Ignore unknown options and configuration directives, rather than
592 * logging them. To be effective, appear in the configuration
593 * before the unknown options. ADNS_RES_OPTIONS is generally early
596 * There are a number of environment variables which can modify the
597 * behaviour of adns. They take effect only if adns_init is used, and
598 * the caller of adns_init can disable them using adns_if_noenv. In
599 * each case there is both a FOO and an ADNS_FOO; the latter is
600 * interpreted later so that it can override the former. Unless
601 * otherwise stated, environment variables are interpreted after
602 * resolv[-adns].conf are read, in the order they are listed here.
604 * RES_CONF, ADNS_RES_CONF
605 * A filename, whose contets are in the format of resolv.conf.
607 * RES_CONF_TEXT, ADNS_RES_CONF_TEXT
608 * A string in the format of resolv.conf.
610 * RES_OPTIONS, ADNS_RES_OPTIONS
611 * These are parsed as if they appeared in the `options' line of a
612 * resolv.conf. In addition to being parsed at this point in the
613 * sequence, they are also parsed at the very beginning before
614 * resolv.conf or any other environment variables are read, so that
615 * any debug option can affect the processing of the configuration.
617 * LOCALDOMAIN, ADNS_LOCALDOMAIN
618 * These are interpreted as if their contents appeared in a `search'
619 * line in resolv.conf.
622 int adns_synchronous(adns_state ads,
625 adns_queryflags flags,
626 adns_answer **answer_r);
628 /* NB: if you set adns_if_noautosys then _submit and _check do not
629 * make any system calls; you must use some of the asynch-io event
630 * processing functions to actually get things to happen.
633 int adns_submit(adns_state ads,
636 adns_queryflags flags,
638 adns_query *query_r);
640 /* The owner should be quoted in master file format. */
642 int adns_check(adns_state ads,
643 adns_query *query_io,
644 adns_answer **answer_r,
647 int adns_wait(adns_state ads,
648 adns_query *query_io,
649 adns_answer **answer_r,
652 /* same as adns_wait but uses poll(2) internally */
653 int adns_wait_poll(adns_state ads,
654 adns_query *query_io,
655 adns_answer **answer_r,
658 void adns_cancel(adns_query query);
660 /* The adns_query you get back from _submit is valid (ie, can be
661 * legitimately passed into adns functions) until it is returned by
662 * adns_check or adns_wait, or passed to adns_cancel. After that it
663 * must not be used. You can rely on it not being reused until the
664 * first adns_submit or _transact call using the same adns_state after
665 * it became invalid, so you may compare it for equality with other
666 * query handles until you next call _query or _transact.
668 * _submit and _synchronous return ENOSYS if they don't understand the
672 int adns_submit_reverse(adns_state ads,
673 const struct sockaddr *addr,
675 adns_queryflags flags,
677 adns_query *query_r);
678 /* type must be _r_ptr or _r_ptr_raw. _qf_search is ignored.
679 * addr->sa_family must be AF_INET or you get ENOSYS.
682 int adns_submit_reverse_any(adns_state ads,
683 const struct sockaddr *addr,
686 adns_queryflags flags,
688 adns_query *query_r);
689 /* For RBL-style reverse `zone's; look up
690 * <reversed-address>.<zone>
691 * Any type is allowed. _qf_search is ignored.
692 * addr->sa_family must be AF_INET or you get ENOSYS.
695 void adns_finish(adns_state ads);
696 /* You may call this even if you have queries outstanding;
697 * they will be cancelled.
700 #define ADNS_ADDR2TEXT_BUFLEN \
701 (INET6_ADDRSTRLEN + 1/*%*/ \
702 + ((IF_NAMESIZE-1) > 9 ? (IF_NAMESIZE-1) : 9/*uint32*/) \
703 + 1/* nul; included in IF_NAMESIZE */)
705 int adns_text2addr(const char *text, uint16_t port, adns_queryflags flags,
706 struct sockaddr *sa_r,
707 socklen_t *salen_io /* updated iff OK or ENOSPC */);
708 int adns_addr2text(const struct sockaddr *sa, adns_queryflags flags,
709 char *buffer, int *buflen_io /* updated ONLY on ENOSPC */,
710 int *port_r /* may be 0 */);
712 * port is always in host byte order and is simply copied to and
713 * from the appropriate sockaddr field (byteswapped as necessary).
715 * The only flags supported are adns_qf_addrlit_...
717 * Error return values are:
719 * ENOSPC Output buffer is too small. Can only happen if
720 * *buflen_io < ADNS_ADDR2TEXT_BUFLEN or
721 * *salen_io < sizeof(adns_sockaddr). On return,
722 * *buflen_io or *salen_io has been updated by adns.
724 * EINVAL text has invalid syntax.
726 * text represents an address family not supported by
727 * this version of adns.
729 * Scoped address supplied (text contained "%" or
730 * sin6_scope_id nonzero) but caller specified
731 * adns_qf_addrlit_scope_forbid.
733 * Scope name (rather than number) supplied in text but
734 * caller specified adns_qf_addrlit_scope_numeric.
736 * EAFNOSUPPORT sa->sa_family is not supported (addr2text only).
738 * ENOSYS Unsupported flags set.
740 * Only if neither adns_qf_addrlit_scope_forbid nor
741 * adns_qf_addrlit_scope_numeric are set:
743 * ENOSYS Scope name supplied in text but IPv6 address part of
744 * sockaddr is not a link local address.
746 * ENXIO Scope name supplied in text but if_nametoindex
747 * said it wasn't a valid local interface name.
749 * EIO Scoped address supplied but if_nametoindex failed
750 * in an unexpected way; adns has printed a message to
753 * any other if_nametoindex failed in a more-or-less expected way.
756 void adns_forallqueries_begin(adns_state ads);
757 adns_query adns_forallqueries_next(adns_state ads, void **context_r);
758 /* Iterator functions, which you can use to loop over the outstanding
759 * (submitted but not yet successfuly checked/waited) queries.
761 * You can only have one iteration going at once. You may call _begin
762 * at any time; after that, an iteration will be in progress. You may
763 * only call _next when an iteration is in progress - anything else
764 * may coredump. The iteration remains in progress until _next
765 * returns 0, indicating that all the queries have been walked over,
766 * or ANY other adns function is called with the same adns_state (or a
767 * query in the same adns_state). There is no need to explicitly
768 * finish an iteration.
770 * context_r may be 0. *context_r may not be set when _next returns 0.
773 void adns_checkconsistency(adns_state ads, adns_query qu);
774 /* Checks the consistency of adns's internal data structures.
775 * If any error is found, the program will abort().
776 * You may pass 0 for qu; if you pass non-null then additional checks
777 * are done to make sure that qu is a valid query.
781 * Example expected/legal calling sequence for submit/check/wait:
787 * adns_check 3 -> EAGAIN
795 * Entrypoints for generic asynch io:
796 * (these entrypoints are not very useful except in combination with *
797 * some of the other I/O model calls which can tell you which fds to
800 * Note that any adns call may cause adns to open and close fds, so
801 * you must call beforeselect or beforepoll again just before
802 * blocking, or you may not have an up-to-date list of it's fds.
805 int adns_processany(adns_state ads);
806 /* Gives adns flow-of-control for a bit. This will never block, and
807 * can be used with any threading/asynch-io model. If some error
808 * occurred which might cause an event loop to spin then the errno
812 int adns_processreadable(adns_state ads, int fd, const struct timeval *now);
813 int adns_processwriteable(adns_state ads, int fd, const struct timeval *now);
814 int adns_processexceptional(adns_state ads, int fd, const struct timeval *now);
815 /* Gives adns flow-of-control so that it can process incoming data
816 * from, or send outgoing data via, fd. Very like _processany. If it
817 * returns zero then fd will no longer be readable or writeable
818 * (unless of course more data has arrived since). adns will _only_
819 * use that fd and only in the manner specified, regardless of whether
820 * adns_if_noautosys was specified.
822 * adns_processexceptional should be called when select(2) reports an
823 * exceptional condition, or poll(2) reports POLLPRI.
825 * It is fine to call _processreabable or _processwriteable when the
826 * fd is not ready, or with an fd that doesn't belong to adns; it will
827 * then just return 0.
829 * If some error occurred which might prevent an event loop to spin
830 * then the errno value is returned.
833 void adns_processtimeouts(adns_state ads, const struct timeval *now);
834 /* Gives adns flow-of-control so that it can process any timeouts
835 * which might have happened. Very like _processreadable/writeable.
837 * now may be 0; if it isn't, *now must be the current time, recently
838 * obtained from gettimeofday.
841 void adns_firsttimeout(adns_state ads,
842 struct timeval **tv_mod, struct timeval *tv_buf,
844 /* Asks adns when it would first like the opportunity to time
845 * something out. now must be the current time, from gettimeofday.
847 * If tv_mod points to 0 then tv_buf must be non-null, and
848 * _firsttimeout will fill in *tv_buf with the time until the first
849 * timeout, and make *tv_mod point to tv_buf. If adns doesn't have
850 * anything that might need timing out it will leave *tv_mod as 0.
852 * If *tv_mod is not 0 then tv_buf is not used. adns will update
853 * *tv_mod if it has any earlier timeout, and leave it alone if it
856 * This call will not actually do any I/O, or change the fds that adns
857 * is using. It always succeeds and never blocks.
860 void adns_globalsystemfailure(adns_state ads);
861 /* If serious problem(s) happen which globally affect your ability to
862 * interact properly with adns, or adns's ability to function
863 * properly, you or adns can call this function.
865 * All currently outstanding queries will be made to fail with
866 * adns_s_systemfail, and adns will close any stream sockets it has
869 * This is used by adns, for example, if gettimeofday() fails.
870 * Without this the program's event loop might start to spin !
872 * This call will never block.
876 * Entrypoints for select-loop based asynch io:
879 void adns_beforeselect(adns_state ads, int *maxfd, fd_set *readfds,
880 fd_set *writefds, fd_set *exceptfds,
881 struct timeval **tv_mod, struct timeval *tv_buf,
882 const struct timeval *now);
883 /* Find out file descriptors adns is interested in, and when it would
884 * like the opportunity to time something out. If you do not plan to
885 * block then tv_mod may be 0. Otherwise, tv_mod and tv_buf are as
886 * for adns_firsttimeout. readfds, writefds, exceptfds and maxfd_io may
889 * If tv_mod is 0 on entry then this will never actually do any I/O,
890 * or change the fds that adns is using or the timeouts it wants. In
891 * any case it won't block, and it will set the timeout to zero if a
892 * query finishes in _beforeselect.
895 void adns_afterselect(adns_state ads, int maxfd, const fd_set *readfds,
896 const fd_set *writefds, const fd_set *exceptfds,
897 const struct timeval *now);
898 /* Gives adns flow-of-control for a bit; intended for use after
899 * select. This is just a fancy way of calling adns_processreadable/
900 * writeable/timeouts as appropriate, as if select had returned the
901 * data being passed. Always succeeds.
905 * Example calling sequence:
907 * adns_init _noautosys
913 * adns_submit / adns_check
919 * Entrypoints for poll-loop based asynch io:
923 /* In case your system doesn't have it or you forgot to include
924 * <sys/poll.h>, to stop the following declarations from causing
925 * problems. If your system doesn't have poll then the following
926 * entrypoints will not be defined in libadns. Sorry !
929 int adns_beforepoll(adns_state ads, struct pollfd *fds,
930 int *nfds_io, int *timeout_io,
931 const struct timeval *now);
932 /* Finds out which fd's adns is interested in, and when it would like
933 * to be able to time things out. This is in a form suitable for use
936 * On entry, usually fds should point to at least *nfds_io structs.
937 * adns will fill up to that many structs will information for poll,
938 * and record in *nfds_io how many structs it filled. If it wants to
939 * listen for more structs then *nfds_io will be set to the number
940 * required and _beforepoll will return ERANGE.
942 * You may call _beforepoll with fds==0 and *nfds_io 0, in which case
943 * adns will fill in the number of fds that it might be interested in
944 * in *nfds_io, and always return either 0 (if it is not interested in
945 * any fds) or ERANGE (if it is).
947 * NOTE that (unless now is 0) adns may acquire additional fds
948 * from one call to the next, so you must put adns_beforepoll in a
949 * loop, rather than assuming that the second call (with the buffer
950 * size requested by the first) will not return ERANGE.
952 * adns only ever sets POLLIN, POLLOUT and POLLPRI in its pollfd
953 * structs, and only ever looks at those bits. POLLPRI is required to
954 * detect TCP Urgent Data (which should not be used by a DNS server)
955 * so that adns can know that the TCP stream is now useless.
957 * In any case, *timeout_io should be a timeout value as for poll(2),
958 * which adns will modify downwards as required. If the caller does
959 * not plan to block then *timeout_io should be 0 on entry, or
960 * alternatively, timeout_io may be 0. (Alternatively, the caller may
961 * use _beforeselect with timeout_io==0 to find out about file
962 * descriptors, and use _firsttimeout is used to find out when adns
963 * might want to time something out.)
965 * adns_beforepoll will return 0 on success, and will not fail for any
966 * reason other than the fds buffer being too small (ERANGE).
968 * This call will never actually do any I/O. If you supply the
969 * current time it will not change the fds that adns is using or the
972 * In any case this call won't block.
975 #define ADNS_POLLFDS_RECOMMENDED 3
976 /* If you allocate an fds buf with at least RECOMMENDED entries then
977 * you are unlikely to need to enlarge it. You are recommended to do
978 * so if it's convenient. However, you must be prepared for adns to
979 * require more space than this.
982 void adns_afterpoll(adns_state ads, const struct pollfd *fds, int nfds,
983 const struct timeval *now);
984 /* Gives adns flow-of-control for a bit; intended for use after
985 * poll(2). fds and nfds should be the results from poll(). pollfd
986 * structs mentioning fds not belonging to adns will be ignored.
990 adns_status adns_rr_info(adns_rrtype type,
991 const char **rrtname_r, const char **fmtname_r,
993 const void *datap, char **data_r);
995 * Get information about a query type, or convert reply data to a
996 * textual form. type must be specified, and the official name of the
997 * corresponding RR type will be returned in *rrtname_r, and
998 * information about the processing style in *fmtname_r. The length
999 * of the table entry in an answer for that type will be returned in
1000 * in *len_r. Any or all of rrtname_r, fmtname_r and len_r may be 0.
1001 * If fmtname_r is non-null then *fmtname_r may be null on return,
1002 * indicating that no special processing is involved.
1004 * data_r be must be non-null iff datap is. In this case *data_r will
1005 * be set to point to a string pointing to a representation of the RR
1006 * data in master file format. (The owner name, timeout, class and
1007 * type will not be present - only the data part of the RR.) The
1008 * memory will have been obtained from malloc() and must be freed by
1011 * Usually this routine will succeed. Possible errors include:
1013 * adns_s_rrtypeunknown
1014 * adns_s_invaliddata (*datap contained garbage)
1015 * If an error occurs then no memory has been allocated,
1016 * and *rrtname_r, *fmtname_r, *len_r and *data_r are undefined.
1018 * There are some adns-invented data formats which are not official
1019 * master file formats. These include:
1021 * Mailboxes if __qtf_mail822: these are just included as-is.
1023 * Addresses (adns_rr_addr): these may be of pretty much any type.
1024 * The representation is in two parts: first, a word for the address
1025 * family (ie, in AF_XXX, the XXX), and then one or more items for the
1026 * address itself, depending on the format. For an IPv4 address the
1027 * syntax is INET followed by the dotted quad (from inet_ntoa).
1028 * Currently only IPv4 is supported.
1030 * Text strings (as in adns_rr_txt) appear inside double quotes, and
1031 * use \" and \\ to represent " and \, and \xHH to represent
1032 * characters not in the range 32-126.
1034 * Hostname with addresses (adns_rr_hostaddr): this consists of the
1035 * hostname, as usual, followed by the adns_status value, as an
1036 * abbreviation, and then a descriptive string (encoded as if it were
1037 * a piece of text), for the address lookup, followed by zero or more
1038 * addresses enclosed in ( and ). If the result was a temporary
1039 * failure, then a single ? appears instead of the ( ). If the
1040 * result was a permanent failure then an empty pair of parentheses
1041 * appears (which a space in between). For example, one of the NS
1042 * records for greenend.org.uk comes out like
1043 * ns.chiark.greenend.org.uk ok "OK" ( INET 195.224.76.132 )
1044 * an MX referring to a nonexistent host might come out like:
1045 * 50 sun2.nsfnet-relay.ac.uk nxdomain "No such domain" ( )
1046 * and if nameserver information is not available you might get:
1047 * dns2.spong.dyn.ml.org timeout "DNS query timed out" ?
1050 const char *adns_strerror(adns_status st);
1051 const char *adns_errabbrev(adns_status st);
1052 const char *adns_errtypeabbrev(adns_status st);
1053 /* Like strerror but for adns_status values. adns_errabbrev returns
1054 * the abbreviation of the error - eg, for adns_s_timeout it returns
1055 * "timeout". adns_errtypeabbrev returns the abbreviation of the
1056 * error class: ie, for values up to adns_s_max_XXX it will return the
1057 * string XXX. You MUST NOT call these functions with status values
1058 * not returned by the same adns library.
1062 } /* end of extern "C" */