* - adns user-visible API (single-threaded, without any locking)
*/
/*
- * This file is part of adns, which is Copyright (C) 1997-1999 Ian Jackson
+ *
+ * This file is
+ * Copyright (C) 1997-1999 Ian Jackson <ian@davenant.greenend.org.uk>
+ *
+ * It is part of adns, which is
+ * Copyright (C) 1997-1999 Ian Jackson <ian@davenant.greenend.org.uk>
+ * Copyright (C) 1999 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
* 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 for the
+ * adns-using part to be distributed separately.
*
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software Foundation,
+ * 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 the body of adns, I think
+ * 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.
*
+ *
* $Id$
*/
#ifndef ADNS_H_INCLUDED
#define ADNS_H_INCLUDED
+#ifdef __cplusplus
+extern "C" { /* I really dislike this - iwj. */
+#endif
#include <stdio.h>
#include <sys/socket.h>
#include <netinet/in.h>
+#include <sys/types.h>
+#include <sys/time.h>
+#include <unistd.h>
/* All struct in_addr anywhere in adns are in NETWORK byte order. */
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= 0x000001, /* use the searchlist */
- adns_qf_usevc= 0x000002, /* use a virtual circuit (TCP connection) */
- adns_qf_owner= 0x000004, /* fill in the owner field in the answer */
- adns_qf_quoteok_query= 0x000010, /* allow quote-requiring chars in query domain */
- adns_qf_quoteok_cname= 0x000020, /* allow ... in CNAME we go via */
- adns_qf_quoteok_anshost= 0x000040, /* allow ... in answers expected to be hostnames */
- adns_qf_cname_loose= 0x000100, /* allow refs to CNAMEs - without, get _s_cname */
- adns_qf_cname_forbid= 0x000200, /* don't follow CNAMEs, instead give _s_cname */
- adns__qf_internalmask= 0x0ff000
+ 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 quote-requiring 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_rrtype;
-/* In queries without qf_quoteok_*, all domains must have standard
- * legal syntax. 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, and on output,
+/*
+ * 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, and on output,
* the char* is a pointer to a string which would be legal either
* inside or outside " delimiters, and any characters not usually
* legal in domain names will be quoted as \X (if the character is
* 33-126 except \ and ") or \DDD.
*
- * Do not ask for _raw records containing mailboxes without
- * specifying _qf_anyquote.
+ * 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 ".) Otherwise the local-part is
+ * presented as-is. In any case this is followed by an @ and the
+ * domain. The domain will not contain any characters not legal in
+ * hostnames. adns will protect the application from local parts
+ * containing control characters - these appear to be legal according
+ * to RFC822 but are clearly a bad idea.
+ *
+ * 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
+ * caswe.
*/
typedef enum {
/* permanent errors */
adns_s_nxdomain,
- adns_s_nodata,
+ adns_s_nodata
} adns_status;
char *owner; /* only set if requested in query flags */
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;
+ int nrrs, rrsz; /* nrrs is 0 if an error occurs */
union {
void *untyped;
unsigned char *bytes;
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. adns_init_strcfg
+ * is instead passed a string which is interpreted as if it were the
+ * contents of resolv.conf. In general, configuration which is set
+ * later overrides any that is set earlier.
+ *
+ * Standard directives understood in resolv.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.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.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.conf is 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,
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,
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
* 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. */
+
void adns_finish(adns_state ads);
/* You may call this even if you have queries outstanding;
* they will be cancelled.
*/
-struct adns_query adns_forallqueries_begin(adns_state ads, void **context_r);
-struct adns_query adns_forallqueries_next(adns_state ads, adns_query, void **context_r);
+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. Each
- * function returns a query handle and a corresponding context pointer,
- * or returns 0 setting *context_r to 0 if there are no (more) queries.
- * There is no need to explicitly finish an iteration. context_r may be 0.
- *
- * IMPORTANT: you MUST NOT call ANY other adns function with the same
- * adns_state, or with a query in the same adns_state, while you are
- * doing one of these iterations. After such a call the iterator
- * value has undefined meaning and must not be used.
+ * (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.
*/
/*
* 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_
- * that fd and only in the manner specified, regardless of whether
+ * 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
* listen for more structs then *nfds_io will be set to the number
* required and _beforepoll will return ERANGE.
*
- * NOTE that if 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.
- *
* 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 0.
+ * 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,
+ * 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.
+ * 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).
*
- * If *now is not 0 then this call 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.
+ * 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
const char **rrtname_r, const char **fmtname_r,
int *len_r,
const void *datap, char **data_r);
-/* Gets information in human-readable (but non-i18n) form
- * for eg debugging purposes. 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 human-readable text
- * string representing the RR data. The text will have
- * been obtained from malloc() and must be freed by the caller.
+/*
+ * 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_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 permanent
+ * failure, then a single ? appears instead of the ( ). If the
+ * result was a temporary 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);
* not returned by the same adns library.
*/
+#ifdef __cplusplus
+} /* end of extern "C" */
+#endif
#endif
~ianmdlvl / adns.git / blobdiff