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NeoStats/include/adns.h

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/* NeoStats - IRC Statistical Services
** Copyright (c) 1999-2008 Adam Rutter, Justin Hammond, Mark Hetherington
** http://www.neostats.net/
**
** Based on adns, which is
** Copyright (C) 1997-2008 Ian Jackson <ian@davenant.greenend.org.uk>
** Copyright (C) 1999-2008 Tony Finch <dot@dotat.at>
**
** This program is free software; you can redistribute it and/or modify
** it under the terms of the GNU General Public License as published by
** the Free Software Foundation; either version 2 of the License, or
** (at your option) any later version.
**
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
** GNU General Public License for more details.
**
** You should have received a copy of the GNU General Public License
** along with this program; if not, write to the Free Software
** Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
** USA
**
** NeoStats CVS Identification
** $Id$
*/
/*
* adns.h
* - adns user-visible API (single-threaded, without any locking)
*/
#ifndef ADNS_H_INCLUDED
#define ADNS_H_INCLUDED
#ifdef WIN32
#if defined (_MSC_VER)
#pragma warning(disable:4003)
#endif /* _MSC_VER */
#include <winsock2.h>
#include <windows.h>
#ifdef HAVE_LIMITS_H
#include <limits.h>
#endif /* HAVE_LIMITS_H */
#ifdef HAVE_MALLOC_H
#include <malloc.h>
#endif /* HAVE_MALLOC_H */
#define ENOPROTOOPT WSAENOPROTOOPT
#endif
#ifdef __cplusplus
extern "C" { /* I really dislike this - iwj. */
#endif
/* All struct in_addr anywhere in adns are in NETWORK byte order. */
typedef struct adns__state *adns_state;
typedef struct adns__query *adns_query;
typedef enum {
adns_if_noenv = 0x0001, /* do not look at environment */
adns_if_noerrprint = 0x0002, /* never print output to stderr (_debug overrides) */
adns_if_noserverwarn = 0x0004, /* do not warn to stderr about duff nameservers etc */
adns_if_debug = 0x0008, /* enable all output to stderr plus debug msgs */
adns_if_logpid = 0x0080, /* include pid in diagnostic output */
adns_if_noautosys = 0x0010, /* do not make syscalls at every opportunity */
adns_if_eintr = 0x0020, /* allow _wait and _synchronous to return EINTR */
adns_if_nosigpipe = 0x0040, /* applic has SIGPIPE set to SIG_IGN, do not protect */
adns_if_checkc_entex = 0x0100, /* do consistency checks on entry/exit to adns funcs */
adns_if_checkc_freq = 0x0300 /* do consistency checks very frequently (slow!) */
} adns_initflags;
typedef enum {
adns_qf_search = 0x00000001, /* use the searchlist */
adns_qf_usevc = 0x00000002, /* use a virtual circuit (TCP connection) */
adns_qf_owner = 0x00000004, /* fill in the owner field in the answer */
adns_qf_quoteok_query = 0x00000010, /* allow special chars in query domain */
adns_qf_quoteok_cname = 0x00000000, /* allow ... in CNAME we go via - now default */
adns_qf_quoteok_anshost = 0x00000040, /* allow ... in things supposed to be hostnames */
adns_qf_quotefail_cname = 0x00000080, /* refuse if quote-req chars in CNAME we go via */
adns_qf_cname_loose = 0x00000100, /* allow refs to CNAMEs - without, get _s_cname */
adns_qf_cname_forbid = 0x00000200, /* don't follow CNAMEs, instead give _s_cname */
adns__qf_internalmask = 0x0ff00000
} adns_queryflags;
typedef enum {
adns__rrt_typemask = 0x0ffff,
adns__qtf_deref = 0x10000, /* dereference domains and perhaps produce extra data */
adns__qtf_mail822 = 0x20000, /* make mailboxes be in RFC822 rcpt field format */
adns_r_none = 0,
adns_r_a = 1,
adns_r_ns_raw = 2,
adns_r_ns = adns_r_ns_raw | adns__qtf_deref,
adns_r_cname = 5,
adns_r_soa_raw = 6,
adns_r_soa = adns_r_soa_raw | adns__qtf_mail822,
adns_r_ptr_raw = 12,
adns_r_ptr = adns_r_ptr_raw | adns__qtf_deref,
adns_r_hinfo = 13,
adns_r_mx_raw = 15,
adns_r_mx = adns_r_mx_raw | adns__qtf_deref,
adns_r_txt = 16,
adns_r_rp_raw = 17,
adns_r_rp = adns_r_rp_raw | adns__qtf_mail822,
adns_r_addr = adns_r_a | adns__qtf_deref
} adns_rrtype;
/*
* In queries without qf_quoteok_*, all domains must have standard
* legal syntax, or you get adns_s_querydomainvalid (if the query
* domain contains bad characters) or adns_s_answerdomaininvalid (if
* the answer contains bad characters).
*
* In queries _with_ qf_quoteok_*, domains in the query or response
* may contain any characters, quoted according to RFC1035 5.1. On
* input to adns, the char* is a pointer to the interior of a "
* delimited string, except that " may appear in it unquoted. On
* output, the char* is a pointer to a string which would be legal
* either inside or outside " delimiters; any character which isn't
* legal in a hostname (ie alphanumeric or hyphen) or one of _ / +
* (the three other punctuation characters commonly abused in domain
* names) will be quoted, as \X if it is a printing ASCII character or
* \DDD otherwise.
*
* If the query goes via a CNAME then the canonical name (ie, the
* thing that the CNAME record refers to) is usually allowed to
* contain any characters, which will be quoted as above. With
* adns_qf_quotefail_cname you get adns_s_answerdomaininvalid when
* this happens. (This is a change from version 0.4 and earlier, in
* which failing the query was the default, and you had to say
* adns_qf_quoteok_cname to avoid this; that flag is now deprecated.)
*
* In version 0.4 and earlier, asking for _raw records containing
* mailboxes without specifying _qf_quoteok_anshost was silly. This
* is no longer the case. In this version only parts of responses
* that are actually supposed to be hostnames will be refused by
* default if quote-requiring characters are found.
*/
/*
* If you ask for an RR which contains domains which are actually
* encoded mailboxes, and don't ask for the _raw version, then adns
* returns the mailbox formatted suitably for an RFC822 recipient
* header field. The particular format used is that if the mailbox
* requires quoting according to the rules in RFC822 then the
* local-part is quoted in double quotes, which end at the next
* unescaped double quote (\ is the escape char, and is doubled, and
* is used to escape only \ and "). If the local-part is legal
* without quoting according to RFC822, it is presented as-is. In any
* case the local-part is followed by an @ and the domain. The domain
* will not contain any characters not legal in hostnames.
*
* Unquoted local-parts may contain any printing 7-bit ASCII
* except the punctuation characters ( ) < > @ , ; : \ " [ ]
* I.e. they may contain alphanumerics, and the following
* punctuation characters: ! # % ^ & * - _ = + { } .
*
* adns will reject local parts containing control characters (byte
* values 0-31, 127-159, and 255) - these appear to be legal according
* to RFC822 (at least 0-127) but are clearly a bad idea. RFC1035
* syntax does not make any distinction between a single RFC822
* quoted-string containing full stops, and a series of quoted-strings
* separated by full stops; adns will return anything that isn't all
* valid atoms as a single quoted-string. RFC822 does not allow
* high-bit-set characters at all, but adns does allow them in
* local-parts, treating them as needing quoting.
*
* If you ask for the domain with _raw then _no_ checking is done
* (even on the host part, regardless of adns_qf_quoteok_anshost), and
* you just get the domain name in master file format.
*
* If no mailbox is supplied the returned string will be `.' in either
* case.
*/
typedef enum {
adns_s_ok,
/* locally induced errors */
adns_s_nomemory,
adns_s_unknownrrtype,
adns_s_systemfail,
adns_s_max_localfail = 29,
/* remotely induced errors, detected locally */
adns_s_timeout,
adns_s_allservfail,
adns_s_norecurse,
adns_s_invalidresponse,
adns_s_unknownformat,
adns_s_max_remotefail = 59,
/* remotely induced errors, reported by remote server to us */
adns_s_rcodeservfail,
adns_s_rcodeformaterror,
adns_s_rcodenotimplemented,
adns_s_rcoderefused,
adns_s_rcodeunknown,
adns_s_max_tempfail = 99,
/* remote configuration errors */
adns_s_inconsistent, /* PTR gives domain whose A does not exist and match */
adns_s_prohibitedcname, /* CNAME found where eg A expected (not if _qf_loosecname) */
adns_s_answerdomaininvalid,
adns_s_answerdomaintoolong,
adns_s_invaliddata,
adns_s_max_misconfig = 199,
/* permanent problems with the query */
adns_s_querydomainwrong,
adns_s_querydomaininvalid,
adns_s_querydomaintoolong,
adns_s_max_misquery = 299,
/* permanent errors */
adns_s_nxdomain,
adns_s_nodata,
adns_s_max_permfail = 499
} adns_status;
typedef struct {
int len;
union {
struct sockaddr sa;
struct sockaddr_in inet;
} addr;
} adns_rr_addr;
typedef struct {
char *host;
adns_status astatus;
int naddrs; /* temp fail => -1, perm fail => 0, s_ok => >0 */
adns_rr_addr *addrs;
} adns_rr_hostaddr;
typedef struct {
char *(array[2]);
} adns_rr_strpair;
typedef struct {
int i;
adns_rr_hostaddr ha;
} adns_rr_inthostaddr;
typedef struct {
/* Used both for mx_raw, in which case i is the preference and str the domain,
* and for txt, in which case each entry has i for the `text' length,
* and str for the data (which will have had an extra nul appended
* so that if it was plain text it is now a null-terminated string).
*/
int i;
char *str;
} adns_rr_intstr;
typedef struct {
adns_rr_intstr array[2];
} adns_rr_intstrpair;
typedef struct {
char *mname, *rname;
unsigned long serial, refresh, retry, expire, minimum;
} adns_rr_soa;
typedef struct {
adns_status status;
char *cname; /* always NULL if query was for CNAME records */
char *owner; /* only set if requested in query flags, and may be 0 on error anyway */
adns_rrtype type; /* guaranteed to be same as in query */
time_t expires; /* expiry time, defined only if _s_ok, nxdomain or nodata. NOT TTL! */
int nrrs, rrsz; /* nrrs is 0 if an error occurs */
union {
void *untyped;
unsigned char *bytes;
char *(*str); /* ns_raw, cname, ptr, ptr_raw */
adns_rr_intstr *(*manyistr); /* txt (list of strings ends with i=-1, str=0) */
adns_rr_addr *addr; /* addr */
struct in_addr *inaddr; /* a */
adns_rr_hostaddr *hostaddr; /* ns */
adns_rr_intstrpair *intstrpair; /* hinfo */
adns_rr_strpair *strpair; /* rp, rp_raw */
adns_rr_inthostaddr *inthostaddr; /* mx */
adns_rr_intstr *intstr; /* mx_raw */
adns_rr_soa *soa; /* soa, soa_raw */
} rrs;
} adns_answer;
/* Memory management:
* adns_state and adns_query are actually pointers to malloc'd state;
* On submission questions are copied, including the owner domain;
* Answers are malloc'd as a single piece of memory; pointers in the
* answer struct point into further memory in the answer.
* query_io:
* Must always be non-null pointer;
* If *query_io is 0 to start with then any query may be returned;
* If *query_io is !0 adns_query then only that query may be returned.
* If the call is successful, *query_io, *answer_r, and *context_r
* will all be set.
* Errors:
* Return values are 0 or an errno value.
*
* For _init, _init_strcfg, _submit and _synchronous, system errors
* (eg, failure to create sockets, malloc failure, etc.) return errno
* values.
*
* For _wait and _check failures are reported in the answer
* structure, and only 0, ESRCH or (for _check) EAGAIN is
* returned: if no (appropriate) requests are done adns_check returns
* EAGAIN; if no (appropriate) requests are outstanding both
* adns_query and adns_wait return ESRCH.
*
* Additionally, _wait can return EINTR if you set adns_if_eintr.
*
* All other errors (nameserver failure, timed out connections, &c)
* are returned in the status field of the answer. After a
* successful _wait or _check, if status is nonzero then nrrs will be
* 0, otherwise it will be >0. type will always be the type
* requested.
*/
/* this is called when there is a update for a socket */
typedef void (*fd_update) (int fd, short what);
EXPORTFUNC int adns_init(adns_state *newstate_r, adns_initflags flags,
FILE * diagfile /*0=>stderr */, fd_update func );
EXPORTFUNC int adns_init_strcfg(adns_state *newstate_r, adns_initflags flags,
FILE *diagfile /*0=>discard*/, const char *configtext);
/* Configuration:
* adns_init reads /etc/resolv.conf, which is expected to be (broadly
* speaking) in the format expected by libresolv, and then
* /etc/resolv-adns.conf if it exists. adns_init_strcfg is instead
* passed a string which is interpreted as if it were the contents of
* resolv.conf or resolv-adns.conf. In general, configuration which
* is set later overrides any that is set earlier.
*
* Standard directives understood in resolv[-adns].conf:
*
* nameserver <address>
* Must be followed by the IP address of a nameserver. Several
* nameservers may be specified, and they will be tried in the order
* found. There is a compiled in limit, currently 5, on the number
* of nameservers. (libresolv supports only 3 nameservers.)
*
* search <domain> ...
* Specifies the search list for queries which specify
* adns_qf_search. This is a list of domains to append to the query
* domain. The query domain will be tried as-is either before all
* of these or after them, depending on the ndots option setting
* (see below).
*
* domain <domain>
* This is present only for backward compatibility with obsolete
* versions of libresolv. It should not be used, and is interpreted
* by adns as if it were `search' - note that this is subtly
* different to libresolv's interpretation of this directive.
*
* sortlist <addr>/<mask> ...
* Should be followed by a sequence of IP-address and netmask pairs,
* separated by spaces. They may be specified as
* eg. 172.30.206.0/24 or 172.30.206.0/255.255.255.0. Currently up
* to 15 pairs may be specified (but note that libresolv only
* supports up to 10).
*
* options
* Should followed by one or more options, separated by spaces.
* Each option consists of an option name, followed by optionally
* a colon and a value. Options are listed below.
*
* Non-standard directives understood in resolv[-adns].conf:
*
* clearnameservers
* Clears the list of nameservers, so that further nameserver lines
* start again from the beginning.
*
* include <filename>
* The specified file will be read.
*
* Additionally, adns will ignore lines in resolv[-adns].conf which
* start with a #.
*
* Standard options understood:
*
* debug
* Enables debugging output from the resolver, which will be written
* to stderr.
*
* ndots:<count>
* Affects whether queries with adns_qf_search will be tried first
* without adding domains from the searchlist, or whether the bare
* query domain will be tried last. Queries which contain at least
* <count> dots will be tried bare first. The default is 1.
*
* Non-standard options understood:
*
* adns_checkc:none
* adns_checkc:entex
* adns_checkc:freq
* Changes the consistency checking frequency; this overrides the
* setting of adns_if_check_entex, adns_if_check_freq, or neither,
* in the flags passed to adns_init.
*
* There are a number of environment variables which can modify the
* behaviour of adns. They take effect only if adns_init is used, and
* the caller of adns_init can disable them using adns_if_noenv. In
* each case there is both a FOO and an ADNS_FOO; the latter is
* interpreted later so that it can override the former. Unless
* otherwise stated, environment variables are interpreted after
* resolv[-adns].conf are read, in the order they are listed here.
*
* RES_CONF, ADNS_RES_CONF
* A filename, whose contets are in the format of resolv.conf.
*
* RES_CONF_TEXT, ADNS_RES_CONF_TEXT
* A string in the format of resolv.conf.
*
* RES_OPTIONS, ADNS_RES_OPTIONS
* These are parsed as if they appeared in the `options' line of a
* resolv.conf. In addition to being parsed at this point in the
* sequence, they are also parsed at the very beginning before
* resolv.conf or any other environment variables are read, so that
* any debug option can affect the processing of the configuration.
*
* LOCALDOMAIN, ADNS_LOCALDOMAIN
* These are interpreted as if their contents appeared in a `search'
* line in resolv.conf.
*/
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
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