/* * adns.h * - adns user-visible API */ /* * * This file is * Copyright (C) 1997-2000,2003,2006 Ian Jackson * * It is part of adns, which is * Copyright (C) 1997-2000,2003,2006 Ian Jackson * Copyright (C) 1999-2000,2003,2006 Tony Finch * Copyright (C) 1991 Massachusetts Institute of Technology * * 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, 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. * * * For the benefit of certain LGPL'd `omnibus' software which * provides a uniform interface to various things including adns, I * make the following additional licence. I do this because the GPL * would otherwise force either the omnibus software to be GPL'd or * the adns-using part to be distributed separately. * * So: you may also redistribute and/or modify adns.h (but only the * public header file adns.h and not any other part of adns) under the * terms of the GNU Library General Public License as published by the * Free Software Foundation; either version 2 of the License, or (at * your option) any later version. * * Note that adns itself is GPL'd. Authors of adns-using applications * with GPL-incompatible licences, and people who distribute adns with * applications where the whole distribution is not GPL'd, are still * likely to be in violation of the GPL. Anyone who wants to do this * should contact Ian Jackson. Please note that to avoid encouraging * people to infringe the GPL as it applies to the body of adns, Ian * thinks that if you take advantage of the special exception to * redistribute just adns.h under the LGPL, you should retain this * paragraph in its place in the appropriate copyright statements. * * * You should have received a copy of the GNU General Public License, * or the GNU Library General Public License, as appropriate, along * with this program; if not, write to the Free Software Foundation, * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. * * * $Id: adns.h,v 1.96 2006/08/09 11:16:59 ian Exp $ */ #ifndef ADNS_H_INCLUDED #define ADNS_H_INCLUDED #include #include #include #ifdef _WIN32 # include #else # include # include #endif #include #include #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 { /* In general, or together the desired flags: */ adns_if_none= 0x0000,/* no flags. nicer than 0 for some compilers */ adns_if_noenv= 0x0001,/* do not look at environment */ adns_if_noerrprint= 0x0002,/* never print to stderr (_debug overrides) */ adns_if_noserverwarn=0x0004,/* do not warn to stderr about duff servers 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 ignored, do not protect */ adns_if_checkc_entex=0x0100,/* consistency checks on entry/exit to adns fns */ adns_if_checkc_freq= 0x0300,/* consistency checks very frequently (slow!) */ adns_if_tormode= 0x1000 /* route all trafic via TOR. */ } adns_initflags; typedef enum { /* In general, or together the desired flags: */ adns_qf_none= 0x00000000,/* no flags */ adns_qf_search= 0x00000001,/* use the searchlist */ adns_qf_usevc= 0x00000002,/* use a virtual circuit (TCP conn) */ 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,/* ... in CNAME we go via (now default) */ adns_qf_quoteok_anshost=0x00000040,/* ... in things supposedly 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; perhaps get extra data */ adns__qtf_mail822= 0x20000,/* return mailboxes in RFC822 rcpt field fmt */ adns_r_unknown= 0x40000, /* To use this, ask for records of type |adns_r_unknown. * adns will not process the RDATA - you'll get adns_rr_byteblocks, * where the int is the length and the unsigned char* points to the * data. String representation of the RR data (by adns_rrinfo) is as in * RFC3597. adns_rr_info will not return the type name in *rrtname_r * (due to memory management problems); *fmtname_r will be set to * "unknown". * * Do not specify adns_r_unknown along with a known RR type which * requires domain name uncompression (see RFC3597 s4); domain names * will not be uncompressed and the resulting data would be useless. * Asking for meta-RR types via adns_r_unknown will not work properly * either and may make adns complain about server misbehaviour, so don't * do that. * * Don't forget adns_qf_quoteok if that's what you want. */ 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, /* do not mind PTR with wrong or missing A */ 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_aaaa= 28, /* RFC3596 */ /* For SRV records, query domain without _qf_quoteok_query must look * as expected from SRV RFC with hostname-like Name. _With_ * _quoteok_query, any query domain is allowed. */ adns_r_srv_raw= 33, adns_r_srv= adns_r_srv_raw|adns__qtf_deref, 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, but 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 { int priority, weight, port; char *host; } adns_rr_srvraw; typedef struct { int priority, weight, port; adns_rr_hostaddr ha; } adns_rr_srvha; typedef struct { int len; unsigned char *data; } adns_rr_byteblock; typedef struct { adns_status status; char *cname; /* always NULL if query was for CNAME records */ char *owner; /* only set if req'd in query flags; maybe 0 on error anyway */ adns_rrtype type; /* guaranteed to be same as in query */ time_t expires;/*abs time. def 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 strs ends with i=-1, str=0)*/ adns_rr_addr *addr; /* addr */ struct in_addr *inaddr; /* a */ struct in6_addr *in6addr; /* aaaa */ 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 */ adns_rr_srvraw *srvraw; /* srv_raw */ adns_rr_srvha *srvha;/* srv */ adns_rr_byteblock *byteblock; /* ...|unknown */ } 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. EINVAL from _init et al means the configuration file * is erroneous and cannot be parsed. * * 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. */ /* Threads: * adns does not use any static modifiable state, so it * is safe to call adns_init several times and then use the * resulting adns_states concurrently. * However, it is NOT safe to make simultaneous calls into * adns using the same adns_state; a single adns_state must be used * only by one thread at a time. You can solve this problem by * having one adns_state per thread, or if that isn't feasible, you * could maintain a pool of adns_states. Unfortunately neither of * these approaches has optimal performance. */ int adns_init(adns_state *newstate_r, adns_initflags flags, FILE *diagfile /*0=>stderr*/); int adns_init_strcfg(adns_state *newstate_r, adns_initflags flags, FILE *diagfile /*0=>discard*/, const char *configtext); typedef void adns_logcallbackfn(adns_state ads, void *logfndata, const char *fmt, va_list al); /* Will be called perhaps several times for each message; when the * message is complete, the string implied by fmt and al will end in * a newline. Log messages start with `adns debug:' or `adns * warning:' or `adns:' (for errors), or `adns debug [PID]:' * etc. if adns_if_logpid is set. */ int adns_init_logfn(adns_state *newstate_r, adns_initflags flags, const char *configtext /*0=>use default config files*/, adns_logcallbackfn *logfn /*0=>logfndata is a FILE* */, void *logfndata /*0 with logfn==0 => discard*/); /* 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
* 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 ... * 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 * 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 / ... * 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 * 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: * 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 * 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. * * adns_tormode * Forces the use of virtual circuits over a SOCKS5 proxy running at * port 9050. No UDP based communication is done. * * adns_sockscred:username:password * Use username and password for SOCKS5 authentication. Default is * no authentication. * * 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. */ 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. */ 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. */ int adns_check(adns_state ads, adns_query *query_io, adns_answer **answer_r, void **context_r); 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 */ int adns_wait_poll(adns_state ads, adns_query *query_io, adns_answer **answer_r, void **context_r); 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. */ 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. */ 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 * . * Any type is allowed. _qf_search is ignored. * addr->sa_family must be AF_INET or you get ENOSYS. */ void adns_finish(adns_state ads); /* You may call this even if you have queries outstanding; * they will be cancelled. */ void adns_forallqueries_begin(adns_state ads); 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. */ 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. */ 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. */ int adns_processreadable(adns_state ads, int fd, const struct timeval *now); int adns_processwriteable(adns_state ads, int fd, const struct timeval *now); int adns_processexceptional(adns_state ads, int 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. */ 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. */ 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. */ 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: */ 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 tv_mod is 0 on entry 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. */ 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 * , 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 ! */ 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. */ 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. */ 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" ? */ const char *adns_strerror(adns_status st); const char *adns_errabbrev(adns_status st); 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. */ void adns_free(void *p); /* This is a wrapper around free(3); in general there is no need to * use it. However, when using the Windows DLL the use of this * wrapper is suggested to avoid problems with mixed C runtime * libraries. */ #ifdef __cplusplus } /* end of extern "C" */ #endif #endif