819 lines
31 KiB
C
819 lines
31 KiB
C
/* NeoStats - IRC Statistical Services
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** Copyright (c) 1999-2008 Adam Rutter, Justin Hammond, Mark Hetherington
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** http://www.neostats.net/
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**
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** Based on adns, which is
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** Copyright (C) 1997-2008 Ian Jackson <ian@davenant.greenend.org.uk>
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** Copyright (C) 1999-2008 Tony Finch <dot@dotat.at>
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**
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** This program is free software; you can redistribute it and/or modify
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** it under the terms of the GNU General Public License as published by
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** the Free Software Foundation; either version 2 of the License, or
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** (at your option) any later version.
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**
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** This program is distributed in the hope that it will be useful,
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** but WITHOUT ANY WARRANTY; without even the implied warranty of
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** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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** GNU General Public License for more details.
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**
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** You should have received a copy of the GNU General Public License
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** along with this program; if not, write to the Free Software
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** Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
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** USA
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**
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** NeoStats CVS Identification
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** $Id$
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*/
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/*
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* adns.h
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* - adns user-visible API (single-threaded, without any locking)
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*/
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#ifndef ADNS_H_INCLUDED
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#define ADNS_H_INCLUDED
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#ifdef WIN32
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#if defined (_MSC_VER)
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#pragma warning(disable:4003)
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#endif /* _MSC_VER */
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#include <winsock2.h>
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#include <windows.h>
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#ifdef HAVE_LIMITS_H
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#include <limits.h>
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#endif /* HAVE_LIMITS_H */
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#ifdef HAVE_MALLOC_H
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#include <malloc.h>
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#endif /* HAVE_MALLOC_H */
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#define ENOPROTOOPT WSAENOPROTOOPT
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#endif
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#ifdef __cplusplus
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extern "C" { /* I really dislike this - iwj. */
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#endif
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/* All struct in_addr anywhere in adns are in NETWORK byte order. */
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typedef struct adns__state *adns_state;
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typedef struct adns__query *adns_query;
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typedef enum {
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adns_if_noenv = 0x0001, /* do not look at environment */
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adns_if_noerrprint = 0x0002, /* never print output to stderr (_debug overrides) */
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adns_if_noserverwarn = 0x0004, /* do not warn to stderr about duff nameservers etc */
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adns_if_debug = 0x0008, /* enable all output to stderr plus debug msgs */
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adns_if_logpid = 0x0080, /* include pid in diagnostic output */
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adns_if_noautosys = 0x0010, /* do not make syscalls at every opportunity */
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adns_if_eintr = 0x0020, /* allow _wait and _synchronous to return EINTR */
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adns_if_nosigpipe = 0x0040, /* applic has SIGPIPE set to SIG_IGN, do not protect */
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adns_if_checkc_entex = 0x0100, /* do consistency checks on entry/exit to adns funcs */
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adns_if_checkc_freq = 0x0300 /* do consistency checks very frequently (slow!) */
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} adns_initflags;
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typedef enum {
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adns_qf_search = 0x00000001, /* use the searchlist */
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adns_qf_usevc = 0x00000002, /* use a virtual circuit (TCP connection) */
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adns_qf_owner = 0x00000004, /* fill in the owner field in the answer */
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adns_qf_quoteok_query = 0x00000010, /* allow special chars in query domain */
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adns_qf_quoteok_cname = 0x00000000, /* allow ... in CNAME we go via - now default */
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adns_qf_quoteok_anshost = 0x00000040, /* allow ... in things supposed to be hostnames */
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adns_qf_quotefail_cname = 0x00000080, /* refuse if quote-req chars in CNAME we go via */
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adns_qf_cname_loose = 0x00000100, /* allow refs to CNAMEs - without, get _s_cname */
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adns_qf_cname_forbid = 0x00000200, /* don't follow CNAMEs, instead give _s_cname */
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adns__qf_internalmask = 0x0ff00000
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} adns_queryflags;
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typedef enum {
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adns__rrt_typemask = 0x0ffff,
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adns__qtf_deref = 0x10000, /* dereference domains and perhaps produce extra data */
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adns__qtf_mail822 = 0x20000, /* make mailboxes be in RFC822 rcpt field format */
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adns_r_none = 0,
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adns_r_a = 1,
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adns_r_ns_raw = 2,
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adns_r_ns = adns_r_ns_raw | adns__qtf_deref,
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adns_r_cname = 5,
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adns_r_soa_raw = 6,
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adns_r_soa = adns_r_soa_raw | adns__qtf_mail822,
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adns_r_ptr_raw = 12,
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adns_r_ptr = adns_r_ptr_raw | adns__qtf_deref,
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adns_r_hinfo = 13,
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adns_r_mx_raw = 15,
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adns_r_mx = adns_r_mx_raw | adns__qtf_deref,
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adns_r_txt = 16,
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adns_r_rp_raw = 17,
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adns_r_rp = adns_r_rp_raw | adns__qtf_mail822,
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adns_r_addr = adns_r_a | adns__qtf_deref
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} adns_rrtype;
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/*
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* In queries without qf_quoteok_*, all domains must have standard
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* legal syntax, or you get adns_s_querydomainvalid (if the query
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* domain contains bad characters) or adns_s_answerdomaininvalid (if
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* the answer contains bad characters).
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*
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* In queries _with_ qf_quoteok_*, domains in the query or response
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* may contain any characters, quoted according to RFC1035 5.1. On
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* input to adns, the char* is a pointer to the interior of a "
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* delimited string, except that " may appear in it unquoted. On
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* output, the char* is a pointer to a string which would be legal
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* either inside or outside " delimiters; any character which isn't
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* legal in a hostname (ie alphanumeric or hyphen) or one of _ / +
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* (the three other punctuation characters commonly abused in domain
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* names) will be quoted, as \X if it is a printing ASCII character or
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* \DDD otherwise.
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*
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* If the query goes via a CNAME then the canonical name (ie, the
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* thing that the CNAME record refers to) is usually allowed to
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* contain any characters, which will be quoted as above. With
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* adns_qf_quotefail_cname you get adns_s_answerdomaininvalid when
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* this happens. (This is a change from version 0.4 and earlier, in
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* which failing the query was the default, and you had to say
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* adns_qf_quoteok_cname to avoid this; that flag is now deprecated.)
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*
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* In version 0.4 and earlier, asking for _raw records containing
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* mailboxes without specifying _qf_quoteok_anshost was silly. This
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* is no longer the case. In this version only parts of responses
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* that are actually supposed to be hostnames will be refused by
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* default if quote-requiring characters are found.
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*/
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/*
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* If you ask for an RR which contains domains which are actually
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* encoded mailboxes, and don't ask for the _raw version, then adns
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* returns the mailbox formatted suitably for an RFC822 recipient
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* header field. The particular format used is that if the mailbox
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* requires quoting according to the rules in RFC822 then the
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* local-part is quoted in double quotes, which end at the next
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* unescaped double quote (\ is the escape char, and is doubled, and
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* is used to escape only \ and "). If the local-part is legal
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* without quoting according to RFC822, it is presented as-is. In any
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* case the local-part is followed by an @ and the domain. The domain
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* will not contain any characters not legal in hostnames.
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*
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* Unquoted local-parts may contain any printing 7-bit ASCII
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* except the punctuation characters ( ) < > @ , ; : \ " [ ]
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* I.e. they may contain alphanumerics, and the following
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* punctuation characters: ! # % ^ & * - _ = + { } .
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*
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* adns will reject local parts containing control characters (byte
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* values 0-31, 127-159, and 255) - these appear to be legal according
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* to RFC822 (at least 0-127) but are clearly a bad idea. RFC1035
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* syntax does not make any distinction between a single RFC822
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* quoted-string containing full stops, and a series of quoted-strings
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* separated by full stops; adns will return anything that isn't all
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* valid atoms as a single quoted-string. RFC822 does not allow
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* high-bit-set characters at all, but adns does allow them in
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* local-parts, treating them as needing quoting.
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*
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* If you ask for the domain with _raw then _no_ checking is done
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* (even on the host part, regardless of adns_qf_quoteok_anshost), and
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* you just get the domain name in master file format.
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*
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* If no mailbox is supplied the returned string will be `.' in either
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* case.
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*/
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typedef enum {
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adns_s_ok,
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/* locally induced errors */
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adns_s_nomemory,
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adns_s_unknownrrtype,
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adns_s_systemfail,
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adns_s_max_localfail = 29,
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/* remotely induced errors, detected locally */
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adns_s_timeout,
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adns_s_allservfail,
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adns_s_norecurse,
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adns_s_invalidresponse,
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adns_s_unknownformat,
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adns_s_max_remotefail = 59,
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/* remotely induced errors, reported by remote server to us */
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adns_s_rcodeservfail,
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adns_s_rcodeformaterror,
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adns_s_rcodenotimplemented,
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adns_s_rcoderefused,
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adns_s_rcodeunknown,
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adns_s_max_tempfail = 99,
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/* remote configuration errors */
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adns_s_inconsistent, /* PTR gives domain whose A does not exist and match */
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adns_s_prohibitedcname, /* CNAME found where eg A expected (not if _qf_loosecname) */
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adns_s_answerdomaininvalid,
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adns_s_answerdomaintoolong,
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adns_s_invaliddata,
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adns_s_max_misconfig = 199,
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/* permanent problems with the query */
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adns_s_querydomainwrong,
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adns_s_querydomaininvalid,
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adns_s_querydomaintoolong,
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adns_s_max_misquery = 299,
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/* permanent errors */
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adns_s_nxdomain,
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adns_s_nodata,
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adns_s_max_permfail = 499
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} adns_status;
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typedef struct {
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int len;
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union {
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struct sockaddr sa;
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struct sockaddr_in inet;
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} addr;
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} adns_rr_addr;
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typedef struct {
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char *host;
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adns_status astatus;
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int naddrs; /* temp fail => -1, perm fail => 0, s_ok => >0 */
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adns_rr_addr *addrs;
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} adns_rr_hostaddr;
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typedef struct {
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char *(array[2]);
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} adns_rr_strpair;
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typedef struct {
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int i;
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adns_rr_hostaddr ha;
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} adns_rr_inthostaddr;
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typedef struct {
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/* Used both for mx_raw, in which case i is the preference and str the domain,
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* and for txt, in which case each entry has i for the `text' length,
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* and str for the data (which will have had an extra nul appended
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* so that if it was plain text it is now a null-terminated string).
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*/
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int i;
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char *str;
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} adns_rr_intstr;
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typedef struct {
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adns_rr_intstr array[2];
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} adns_rr_intstrpair;
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typedef struct {
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char *mname, *rname;
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unsigned long serial, refresh, retry, expire, minimum;
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} adns_rr_soa;
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typedef struct {
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adns_status status;
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char *cname; /* always NULL if query was for CNAME records */
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char *owner; /* only set if requested in query flags, and may be 0 on error anyway */
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adns_rrtype type; /* guaranteed to be same as in query */
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time_t expires; /* expiry time, defined only if _s_ok, nxdomain or nodata. NOT TTL! */
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int nrrs, rrsz; /* nrrs is 0 if an error occurs */
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union {
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void *untyped;
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unsigned char *bytes;
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char *(*str); /* ns_raw, cname, ptr, ptr_raw */
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adns_rr_intstr *(*manyistr); /* txt (list of strings ends with i=-1, str=0) */
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adns_rr_addr *addr; /* addr */
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struct in_addr *inaddr; /* a */
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adns_rr_hostaddr *hostaddr; /* ns */
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adns_rr_intstrpair *intstrpair; /* hinfo */
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adns_rr_strpair *strpair; /* rp, rp_raw */
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adns_rr_inthostaddr *inthostaddr; /* mx */
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adns_rr_intstr *intstr; /* mx_raw */
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adns_rr_soa *soa; /* soa, soa_raw */
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} rrs;
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} adns_answer;
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/* Memory management:
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* adns_state and adns_query are actually pointers to malloc'd state;
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* On submission questions are copied, including the owner domain;
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* Answers are malloc'd as a single piece of memory; pointers in the
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* answer struct point into further memory in the answer.
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* query_io:
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* Must always be non-null pointer;
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* If *query_io is 0 to start with then any query may be returned;
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* If *query_io is !0 adns_query then only that query may be returned.
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* If the call is successful, *query_io, *answer_r, and *context_r
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* will all be set.
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* Errors:
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* Return values are 0 or an errno value.
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*
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* For _init, _init_strcfg, _submit and _synchronous, system errors
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* (eg, failure to create sockets, malloc failure, etc.) return errno
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* values.
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*
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* For _wait and _check failures are reported in the answer
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* structure, and only 0, ESRCH or (for _check) EAGAIN is
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* returned: if no (appropriate) requests are done adns_check returns
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* EAGAIN; if no (appropriate) requests are outstanding both
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* adns_query and adns_wait return ESRCH.
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*
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* Additionally, _wait can return EINTR if you set adns_if_eintr.
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*
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* All other errors (nameserver failure, timed out connections, &c)
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* are returned in the status field of the answer. After a
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* successful _wait or _check, if status is nonzero then nrrs will be
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* 0, otherwise it will be >0. type will always be the type
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* requested.
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*/
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/* this is called when there is a update for a socket */
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typedef void (*fd_update) (int fd, short what);
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EXPORTFUNC int adns_init(adns_state *newstate_r, adns_initflags flags,
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FILE * diagfile /*0=>stderr */, fd_update func );
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EXPORTFUNC int adns_init_strcfg(adns_state *newstate_r, adns_initflags flags,
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FILE *diagfile /*0=>discard*/, const char *configtext);
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/* Configuration:
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* adns_init reads /etc/resolv.conf, which is expected to be (broadly
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* speaking) in the format expected by libresolv, and then
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* /etc/resolv-adns.conf if it exists. adns_init_strcfg is instead
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* passed a string which is interpreted as if it were the contents of
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* resolv.conf or resolv-adns.conf. In general, configuration which
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* is set later overrides any that is set earlier.
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*
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* Standard directives understood in resolv[-adns].conf:
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*
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* nameserver <address>
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* Must be followed by the IP address of a nameserver. Several
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* nameservers may be specified, and they will be tried in the order
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* found. There is a compiled in limit, currently 5, on the number
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* of nameservers. (libresolv supports only 3 nameservers.)
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*
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* search <domain> ...
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* Specifies the search list for queries which specify
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* adns_qf_search. This is a list of domains to append to the query
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* domain. The query domain will be tried as-is either before all
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* of these or after them, depending on the ndots option setting
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* (see below).
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*
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* domain <domain>
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* This is present only for backward compatibility with obsolete
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* versions of libresolv. It should not be used, and is interpreted
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* by adns as if it were `search' - note that this is subtly
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* different to libresolv's interpretation of this directive.
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*
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* sortlist <addr>/<mask> ...
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* Should be followed by a sequence of IP-address and netmask pairs,
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* separated by spaces. They may be specified as
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* eg. 172.30.206.0/24 or 172.30.206.0/255.255.255.0. Currently up
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* to 15 pairs may be specified (but note that libresolv only
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* supports up to 10).
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*
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* options
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* Should followed by one or more options, separated by spaces.
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* Each option consists of an option name, followed by optionally
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* a colon and a value. Options are listed below.
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*
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* Non-standard directives understood in resolv[-adns].conf:
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*
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* clearnameservers
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* Clears the list of nameservers, so that further nameserver lines
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* start again from the beginning.
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*
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* include <filename>
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* The specified file will be read.
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*
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* Additionally, adns will ignore lines in resolv[-adns].conf which
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* start with a #.
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*
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* Standard options understood:
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*
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* debug
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* Enables debugging output from the resolver, which will be written
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* to stderr.
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*
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* ndots:<count>
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* Affects whether queries with adns_qf_search will be tried first
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* without adding domains from the searchlist, or whether the bare
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* query domain will be tried last. Queries which contain at least
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* <count> dots will be tried bare first. The default is 1.
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*
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* Non-standard options understood:
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*
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* adns_checkc:none
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* adns_checkc:entex
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* adns_checkc:freq
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* Changes the consistency checking frequency; this overrides the
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* setting of adns_if_check_entex, adns_if_check_freq, or neither,
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* in the flags passed to adns_init.
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*
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* There are a number of environment variables which can modify the
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* behaviour of adns. They take effect only if adns_init is used, and
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* the caller of adns_init can disable them using adns_if_noenv. In
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* each case there is both a FOO and an ADNS_FOO; the latter is
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* interpreted later so that it can override the former. Unless
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* otherwise stated, environment variables are interpreted after
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* resolv[-adns].conf are read, in the order they are listed here.
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*
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* RES_CONF, ADNS_RES_CONF
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* A filename, whose contets are in the format of resolv.conf.
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*
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* RES_CONF_TEXT, ADNS_RES_CONF_TEXT
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* A string in the format of resolv.conf.
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*
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* RES_OPTIONS, ADNS_RES_OPTIONS
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* These are parsed as if they appeared in the `options' line of a
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* resolv.conf. In addition to being parsed at this point in the
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* sequence, they are also parsed at the very beginning before
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* resolv.conf or any other environment variables are read, so that
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* any debug option can affect the processing of the configuration.
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*
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* LOCALDOMAIN, ADNS_LOCALDOMAIN
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* These are interpreted as if their contents appeared in a `search'
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* line in resolv.conf.
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*/
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EXPORTFUNC int adns_synchronous(adns_state ads,
|
|
const char *owner, adns_rrtype type,
|
|
adns_queryflags flags, adns_answer ** answer_r);
|
|
|
|
/* NB: if you set adns_if_noautosys then _submit and _check do not
|
|
* make any system calls; you must use some of the asynch-io event
|
|
* processing functions to actually get things to happen.
|
|
*/
|
|
|
|
EXPORTFUNC int adns_submit(adns_state ads,
|
|
const char *owner, adns_rrtype type,
|
|
adns_queryflags flags, void *context,
|
|
adns_query *query_r);
|
|
|
|
/* The owner should be quoted in master file format. */
|
|
|
|
EXPORTFUNC int adns_check(adns_state ads,
|
|
adns_query * query_io, adns_answer **answer_r,
|
|
void **context_r);
|
|
|
|
EXPORTFUNC int adns_wait(adns_state ads,
|
|
adns_query * query_io, adns_answer **answer_r,
|
|
void **context_r);
|
|
|
|
/* same as adns_wait but uses poll(2) internally */
|
|
EXPORTFUNC int adns_wait_poll(adns_state ads,
|
|
adns_query * query_io, adns_answer **answer_r,
|
|
void **context_r);
|
|
|
|
EXPORTFUNC void adns_cancel(adns_query query);
|
|
|
|
/* The adns_query you get back from _submit is valid (ie, can be
|
|
* legitimately passed into adns functions) until it is returned by
|
|
* adns_check or adns_wait, or passed to adns_cancel. After that it
|
|
* must not be used. You can rely on it not being reused until the
|
|
* first adns_submit or _transact call using the same adns_state after
|
|
* it became invalid, so you may compare it for equality with other
|
|
* query handles until you next call _query or _transact.
|
|
*
|
|
* _submit and _synchronous return ENOSYS if they don't understand the
|
|
* query type.
|
|
*/
|
|
|
|
EXPORTFUNC int adns_submit_reverse(adns_state ads,
|
|
const struct sockaddr *addr, adns_rrtype type,
|
|
adns_queryflags flags, void *context,
|
|
adns_query *query_r);
|
|
/* type must be _r_ptr or _r_ptr_raw. _qf_search is ignored.
|
|
* addr->sa_family must be AF_INET or you get ENOSYS.
|
|
*/
|
|
|
|
EXPORTFUNC int adns_submit_reverse_any(adns_state ads,
|
|
const struct sockaddr *addr, const char *rzone,
|
|
adns_rrtype type, adns_queryflags flags,
|
|
void *context, adns_query *query_r);
|
|
/* For RBL-style reverse `zone's; look up
|
|
* <reversed-address>.<zone>
|
|
* Any type is allowed. _qf_search is ignored.
|
|
* addr->sa_family must be AF_INET or you get ENOSYS.
|
|
*/
|
|
|
|
EXPORTFUNC void adns_finish(adns_state ads);
|
|
/* You may call this even if you have queries outstanding;
|
|
* they will be cancelled.
|
|
*/
|
|
|
|
|
|
EXPORTFUNC void adns_forallqueries_begin(adns_state ads);
|
|
EXPORTFUNC adns_query adns_forallqueries_next(adns_state ads, void **context_r);
|
|
/* Iterator functions, which you can use to loop over the outstanding
|
|
* (submitted but not yet successfuly checked/waited) queries.
|
|
*
|
|
* You can only have one iteration going at once. You may call _begin
|
|
* at any time; after that, an iteration will be in progress. You may
|
|
* only call _next when an iteration is in progress - anything else
|
|
* may coredump. The iteration remains in progress until _next
|
|
* returns 0, indicating that all the queries have been walked over,
|
|
* or ANY other adns function is called with the same adns_state (or a
|
|
* query in the same adns_state). There is no need to explicitly
|
|
* finish an iteration.
|
|
*
|
|
* context_r may be 0. *context_r may not be set when _next returns 0.
|
|
*/
|
|
|
|
EXPORTFUNC void adns_checkconsistency(adns_state ads, adns_query qu);
|
|
/* Checks the consistency of adns's internal data structures.
|
|
* If any error is found, the program will abort().
|
|
* You may pass 0 for qu; if you pass non-null then additional checks
|
|
* are done to make sure that qu is a valid query.
|
|
*/
|
|
|
|
/*
|
|
* Example expected/legal calling sequence for submit/check/wait:
|
|
* adns_init
|
|
* adns_submit 1
|
|
* adns_submit 2
|
|
* adns_submit 3
|
|
* adns_wait 1
|
|
* adns_check 3 -> EAGAIN
|
|
* adns_wait 2
|
|
* adns_wait 3
|
|
* ....
|
|
* adns_finish
|
|
*/
|
|
|
|
/*
|
|
* Entrypoints for generic asynch io:
|
|
* (these entrypoints are not very useful except in combination with *
|
|
* some of the other I/O model calls which can tell you which fds to
|
|
* be interested in):
|
|
*
|
|
* Note that any adns call may cause adns to open and close fds, so
|
|
* you must call beforeselect or beforepoll again just before
|
|
* blocking, or you may not have an up-to-date list of it's fds.
|
|
*/
|
|
|
|
EXPORTFUNC int adns_processany(adns_state ads);
|
|
/* Gives adns flow-of-control for a bit. This will never block, and
|
|
* can be used with any threading/asynch-io model. If some error
|
|
* occurred which might cause an event loop to spin then the errno
|
|
* value is returned.
|
|
*/
|
|
|
|
EXPORTFUNC int adns_processreadable(adns_state ads, OS_SOCKET fd, const struct timeval *now);
|
|
EXPORTFUNC int adns_processwriteable(adns_state ads, OS_SOCKET fd, const struct timeval *now);
|
|
EXPORTFUNC int adns_processexceptional(adns_state ads, OS_SOCKET fd, const struct timeval *now);
|
|
/* Gives adns flow-of-control so that it can process incoming data
|
|
* from, or send outgoing data via, fd. Very like _processany. If it
|
|
* returns zero then fd will no longer be readable or writeable
|
|
* (unless of course more data has arrived since). adns will _only_
|
|
* use that fd and only in the manner specified, regardless of whether
|
|
* adns_if_noautosys was specified.
|
|
*
|
|
* adns_processexceptional should be called when select(2) reports an
|
|
* exceptional condition, or poll(2) reports POLLPRI.
|
|
*
|
|
* It is fine to call _processreabable or _processwriteable when the
|
|
* fd is not ready, or with an fd that doesn't belong to adns; it will
|
|
* then just return 0.
|
|
*
|
|
* If some error occurred which might prevent an event loop to spin
|
|
* then the errno value is returned.
|
|
*/
|
|
|
|
EXPORTFUNC void adns_processtimeouts(adns_state ads, const struct timeval *now);
|
|
/* Gives adns flow-of-control so that it can process any timeouts
|
|
* which might have happened. Very like _processreadable/writeable.
|
|
*
|
|
* now may be 0; if it isn't, *now must be the current time, recently
|
|
* obtained from gettimeofday.
|
|
*/
|
|
|
|
EXPORTFUNC void adns_firsttimeout(adns_state ads,
|
|
struct timeval **tv_mod, struct timeval *tv_buf,
|
|
struct timeval now);
|
|
/* Asks adns when it would first like the opportunity to time
|
|
* something out. now must be the current time, from gettimeofday.
|
|
*
|
|
* If tv_mod points to 0 then tv_buf must be non-null, and
|
|
* _firsttimeout will fill in *tv_buf with the time until the first
|
|
* timeout, and make *tv_mod point to tv_buf. If adns doesn't have
|
|
* anything that might need timing out it will leave *tv_mod as 0.
|
|
*
|
|
* If *tv_mod is not 0 then tv_buf is not used. adns will update
|
|
* *tv_mod if it has any earlier timeout, and leave it alone if it
|
|
* doesn't.
|
|
*
|
|
* This call will not actually do any I/O, or change the fds that adns
|
|
* is using. It always succeeds and never blocks.
|
|
*/
|
|
|
|
EXPORTFUNC void adns_globalsystemfailure(adns_state ads);
|
|
/* If serious problem(s) happen which globally affect your ability to
|
|
* interact properly with adns, or adns's ability to function
|
|
* properly, you or adns can call this function.
|
|
*
|
|
* All currently outstanding queries will be made to fail with
|
|
* adns_s_systemfail, and adns will close any stream sockets it has
|
|
* open.
|
|
*
|
|
* This is used by adns, for example, if gettimeofday() fails.
|
|
* Without this the program's event loop might start to spin !
|
|
*
|
|
* This call will never block.
|
|
*/
|
|
|
|
/*
|
|
* Entrypoints for select-loop based asynch io:
|
|
*/
|
|
|
|
EXPORTFUNC void adns_beforeselect(adns_state ads, int *maxfd, fd_set *readfds,
|
|
fd_set *writefds, fd_set *exceptfds,
|
|
struct timeval **tv_mod, struct timeval *tv_buf,
|
|
const struct timeval *now);
|
|
/* Find out file descriptors adns is interested in, and when it would
|
|
* like the opportunity to time something out. If you do not plan to
|
|
* block then tv_mod may be 0. Otherwise, tv_mod and tv_buf are as
|
|
* for adns_firsttimeout. readfds, writefds, exceptfds and maxfd_io may
|
|
* not be 0.
|
|
*
|
|
* If now is not 0 then this will never actually do any I/O, or change
|
|
* the fds that adns is using or the timeouts it wants. In any case
|
|
* it won't block, and it will set the timeout to zero if a query
|
|
* finishes in _beforeselect.
|
|
*/
|
|
|
|
EXPORTFUNC void adns_afterselect(adns_state ads, int maxfd, const fd_set *readfds,
|
|
const fd_set *writefds, const fd_set *exceptfds, const struct timeval *now);
|
|
/* Gives adns flow-of-control for a bit; intended for use after
|
|
* select. This is just a fancy way of calling adns_processreadable/
|
|
* writeable/timeouts as appropriate, as if select had returned the
|
|
* data being passed. Always succeeds.
|
|
*/
|
|
|
|
/*
|
|
* Example calling sequence:
|
|
*
|
|
* adns_init _noautosys
|
|
* loop {
|
|
* adns_beforeselect
|
|
* select
|
|
* adns_afterselect
|
|
* ...
|
|
* adns_submit / adns_check
|
|
* ...
|
|
* }
|
|
*/
|
|
|
|
/*
|
|
* Entrypoints for poll-loop based asynch io:
|
|
*/
|
|
|
|
struct pollfd;
|
|
/* In case your system doesn't have it or you forgot to include
|
|
* <sys/poll.h>, to stop the following declarations from causing
|
|
* problems. If your system doesn't have poll then the following
|
|
* entrypoints will not be defined in libadns. Sorry !
|
|
*/
|
|
|
|
EXPORTFUNC int adns_beforepoll(adns_state ads, struct pollfd *fds, int *nfds_io, int *timeout_io,
|
|
const struct timeval *now);
|
|
/* Finds out which fd's adns is interested in, and when it would like
|
|
* to be able to time things out. This is in a form suitable for use
|
|
* with poll(2).
|
|
*
|
|
* On entry, usually fds should point to at least *nfds_io structs.
|
|
* adns will fill up to that many structs will information for poll,
|
|
* and record in *nfds_io how many structs it filled. If it wants to
|
|
* listen for more structs then *nfds_io will be set to the number
|
|
* required and _beforepoll will return ERANGE.
|
|
*
|
|
* You may call _beforepoll with fds==0 and *nfds_io 0, in which case
|
|
* adns will fill in the number of fds that it might be interested in
|
|
* in *nfds_io, and always return either 0 (if it is not interested in
|
|
* any fds) or ERANGE (if it is).
|
|
*
|
|
* NOTE that (unless now is 0) adns may acquire additional fds
|
|
* from one call to the next, so you must put adns_beforepoll in a
|
|
* loop, rather than assuming that the second call (with the buffer
|
|
* size requested by the first) will not return ERANGE.
|
|
*
|
|
* adns only ever sets POLLIN, POLLOUT and POLLPRI in its pollfd
|
|
* structs, and only ever looks at those bits. POLLPRI is required to
|
|
* detect TCP Urgent Data (which should not be used by a DNS server)
|
|
* so that adns can know that the TCP stream is now useless.
|
|
*
|
|
* In any case, *timeout_io should be a timeout value as for poll(2),
|
|
* which adns will modify downwards as required. If the caller does
|
|
* not plan to block then *timeout_io should be 0 on entry, or
|
|
* alternatively, timeout_io may be 0. (Alternatively, the caller may
|
|
* use _beforeselect with timeout_io==0 to find out about file
|
|
* descriptors, and use _firsttimeout is used to find out when adns
|
|
* might want to time something out.)
|
|
*
|
|
* adns_beforepoll will return 0 on success, and will not fail for any
|
|
* reason other than the fds buffer being too small (ERANGE).
|
|
*
|
|
* This call will never actually do any I/O. If you supply the
|
|
* current time it will not change the fds that adns is using or the
|
|
* timeouts it wants.
|
|
*
|
|
* In any case this call won't block.
|
|
*/
|
|
|
|
#define ADNS_POLLFDS_RECOMMENDED 2
|
|
/* If you allocate an fds buf with at least RECOMMENDED entries then
|
|
* you are unlikely to need to enlarge it. You are recommended to do
|
|
* so if it's convenient. However, you must be prepared for adns to
|
|
* require more space than this.
|
|
*/
|
|
|
|
EXPORTFUNC void adns_afterpoll(adns_state ads, const struct pollfd *fds, int nfds,
|
|
const struct timeval *now);
|
|
/* Gives adns flow-of-control for a bit; intended for use after
|
|
* poll(2). fds and nfds should be the results from poll(). pollfd
|
|
* structs mentioning fds not belonging to adns will be ignored.
|
|
*/
|
|
|
|
|
|
EXPORTFUNC adns_status adns_rr_info(adns_rrtype type,
|
|
const char **rrtname_r, const char **fmtname_r,
|
|
int *len_r, const void *datap, char **data_r);
|
|
/*
|
|
* Get information about a query type, or convert reply data to a
|
|
* textual form. type must be specified, and the official name of the
|
|
* corresponding RR type will be returned in *rrtname_r, and
|
|
* information about the processing style in *fmtname_r. The length
|
|
* of the table entry in an answer for that type will be returned in
|
|
* in *len_r. Any or all of rrtname_r, fmtname_r and len_r may be 0.
|
|
* If fmtname_r is non-null then *fmtname_r may be null on return,
|
|
* indicating that no special processing is involved.
|
|
*
|
|
* data_r be must be non-null iff datap is. In this case *data_r will
|
|
* be set to point to a string pointing to a representation of the RR
|
|
* data in master file format. (The owner name, timeout, class and
|
|
* type will not be present - only the data part of the RR.) The
|
|
* memory will have been obtained from malloc() and must be freed by
|
|
* the caller.
|
|
*
|
|
* Usually this routine will succeed. Possible errors include:
|
|
* adns_s_nomemory
|
|
* adns_s_rrtypeunknown
|
|
* adns_s_invaliddata (*datap contained garbage)
|
|
* If an error occurs then no memory has been allocated,
|
|
* and *rrtname_r, *fmtname_r, *len_r and *data_r are undefined.
|
|
*
|
|
* There are some adns-invented data formats which are not official
|
|
* master file formats. These include:
|
|
*
|
|
* Mailboxes if __qtf_mail822: these are just included as-is.
|
|
*
|
|
* Addresses (adns_rr_addr): these may be of pretty much any type.
|
|
* The representation is in two parts: first, a word for the address
|
|
* family (ie, in AF_XXX, the XXX), and then one or more items for the
|
|
* address itself, depending on the format. For an IPv4 address the
|
|
* syntax is INET followed by the dotted quad (from inet_ntoa).
|
|
* Currently only IPv4 is supported.
|
|
*
|
|
* Text strings (as in adns_rr_txt) appear inside double quotes, and
|
|
* use \" and \\ to represent " and \, and \xHH to represent
|
|
* characters not in the range 32-126.
|
|
*
|
|
* Hostname with addresses (adns_rr_hostaddr): this consists of the
|
|
* hostname, as usual, followed by the adns_status value, as an
|
|
* abbreviation, and then a descriptive string (encoded as if it were
|
|
* a piece of text), for the address lookup, followed by zero or more
|
|
* addresses enclosed in ( and ). If the result was a temporary
|
|
* failure, then a single ? appears instead of the ( ). If the
|
|
* result was a permanent failure then an empty pair of parentheses
|
|
* appears (which a space in between). For example, one of the NS
|
|
* records for greenend.org.uk comes out like
|
|
* ns.chiark.greenend.org.uk ok "OK" ( INET 195.224.76.132 )
|
|
* an MX referring to a nonexistent host might come out like:
|
|
* 50 sun2.nsfnet-relay.ac.uk nxdomain "No such domain" ( )
|
|
* and if nameserver information is not available you might get:
|
|
* dns2.spong.dyn.ml.org timeout "DNS query timed out" ?
|
|
*/
|
|
|
|
EXPORTFUNC const char *adns_strerror(adns_status st);
|
|
EXPORTFUNC const char *adns_errabbrev(adns_status st);
|
|
EXPORTFUNC const char *adns_errtypeabbrev(adns_status st);
|
|
/* Like strerror but for adns_status values. adns_errabbrev returns
|
|
* the abbreviation of the error - eg, for adns_s_timeout it returns
|
|
* "timeout". adns_errtypeabbrev returns the abbreviation of the
|
|
* error class: ie, for values up to adns_s_max_XXX it will return the
|
|
* string XXX. You MUST NOT call these functions with status values
|
|
* not returned by the same adns library.
|
|
*/
|
|
|
|
#ifdef __cplusplus
|
|
} /* end of extern "C" */
|
|
#endif
|
|
#endif
|