| 1 | /* |
| 2 | * adns.h |
| 3 | * - adns user-visible API (single-threaded, without any locking) |
| 4 | */ |
| 5 | /* |
| 6 | * |
| 7 | * This file is |
| 8 | * Copyright (C) 1997-1999 Ian Jackson <ian@davenant.greenend.org.uk> |
| 9 | * |
| 10 | * It is part of adns, which is |
| 11 | * Copyright (C) 1997-1999 Ian Jackson <ian@davenant.greenend.org.uk> |
| 12 | * Copyright (C) 1999 Tony Finch <dot@dotat.at> |
| 13 | * |
| 14 | * This program is free software; you can redistribute it and/or modify |
| 15 | * it under the terms of the GNU General Public License as published by |
| 16 | * the Free Software Foundation; either version 2, or (at your option) |
| 17 | * any later version. |
| 18 | * |
| 19 | * This program is distributed in the hope that it will be useful, |
| 20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 22 | * GNU General Public License for more details. |
| 23 | * |
| 24 | * |
| 25 | * For the benefit of certain LGPL'd `omnibus' software which provides |
| 26 | * a uniform interface to various things including adns, I make the |
| 27 | * following additional licence. I do this because the GPL would |
| 28 | * otherwise force either the omnibus software to be GPL'd or for the |
| 29 | * adns-using part to be distributed separately. |
| 30 | * |
| 31 | * So, you may also redistribute and/or modify adns.h (but only the |
| 32 | * public header file adns.h and not any other part of adns) under the |
| 33 | * terms of the GNU Library General Public License as published by the |
| 34 | * Free Software Foundation; either version 2 of the License, or (at |
| 35 | * your option) any later version. |
| 36 | * |
| 37 | * Note that adns itself is GPL'd. Authors of adns-using applications |
| 38 | * with GPL-incompatible licences, and people who distribute adns with |
| 39 | * applications where the whole distribution is not GPL'd, are still |
| 40 | * likely to be in violation of the GPL. Anyone who wants to do this |
| 41 | * should contact Ian Jackson. Please note that to avoid encouraging |
| 42 | * people to infringe the GPL as it applies the body of adns, I think |
| 43 | * that if you take advantage of the special exception to redistribute |
| 44 | * just adns.h under the LGPL, you should retain this paragraph in its |
| 45 | * place in the appropriate copyright statements. |
| 46 | * |
| 47 | * |
| 48 | * You should have received a copy of the GNU General Public License, |
| 49 | * or the GNU Library General Public License, as appropriate, along |
| 50 | * with this program; if not, write to the Free Software Foundation, |
| 51 | * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
| 52 | * |
| 53 | * |
| 54 | * $Id: adns.h,v 1.72 1999/11/02 21:02:39 ian Exp $ |
| 55 | */ |
| 56 | |
| 57 | #ifndef ADNS_H_INCLUDED |
| 58 | #define ADNS_H_INCLUDED |
| 59 | #ifdef __cplusplus |
| 60 | extern "C" { /* I really dislike this - iwj. */ |
| 61 | #endif |
| 62 | |
| 63 | #include <stdio.h> |
| 64 | |
| 65 | #include <sys/socket.h> |
| 66 | #include <netinet/in.h> |
| 67 | #include <sys/types.h> |
| 68 | #include <sys/time.h> |
| 69 | #include <unistd.h> |
| 70 | |
| 71 | /* All struct in_addr anywhere in adns are in NETWORK byte order. */ |
| 72 | |
| 73 | typedef struct adns__state *adns_state; |
| 74 | typedef struct adns__query *adns_query; |
| 75 | |
| 76 | typedef enum { |
| 77 | adns_if_noenv= 0x0001, /* do not look at environment */ |
| 78 | adns_if_noerrprint= 0x0002, /* never print output to stderr (_debug overrides) */ |
| 79 | adns_if_noserverwarn= 0x0004, /* do not warn to stderr about duff nameservers etc */ |
| 80 | adns_if_debug= 0x0008, /* enable all output to stderr plus debug msgs */ |
| 81 | adns_if_logpid= 0x0080, /* include pid in diagnostic output */ |
| 82 | adns_if_noautosys= 0x0010, /* do not make syscalls at every opportunity */ |
| 83 | adns_if_eintr= 0x0020, /* allow _wait and _synchronous to return EINTR */ |
| 84 | adns_if_nosigpipe= 0x0040, /* applic has SIGPIPE set to SIG_IGN, do not protect */ |
| 85 | adns_if_checkc_entex= 0x0100, /* do consistency checks on entry/exit to adns funcs */ |
| 86 | adns_if_checkc_freq= 0x0300 /* do consistency checks very frequently (slow!) */ |
| 87 | } adns_initflags; |
| 88 | |
| 89 | typedef enum { |
| 90 | adns_qf_search= 0x00000001, /* use the searchlist */ |
| 91 | adns_qf_usevc= 0x00000002, /* use a virtual circuit (TCP connection) */ |
| 92 | adns_qf_owner= 0x00000004, /* fill in the owner field in the answer */ |
| 93 | adns_qf_quoteok_query= 0x00000010, /* allow quote-requiring chars in query domain */ |
| 94 | adns_qf_quoteok_cname= 0x00000000, /* allow ... in CNAME we go via - now default */ |
| 95 | adns_qf_quoteok_anshost= 0x00000040, /* allow ... in things supposed to be hostnames */ |
| 96 | adns_qf_quotefail_cname= 0x00000080, /* refuse if quote-req chars in CNAME we go via */ |
| 97 | adns_qf_cname_loose= 0x00000100, /* allow refs to CNAMEs - without, get _s_cname */ |
| 98 | adns_qf_cname_forbid= 0x00000200, /* don't follow CNAMEs, instead give _s_cname */ |
| 99 | adns__qf_internalmask= 0x0ff00000 |
| 100 | } adns_queryflags; |
| 101 | |
| 102 | typedef enum { |
| 103 | adns__rrt_typemask= 0x0ffff, |
| 104 | adns__qtf_deref= 0x10000, /* dereference domains and perhaps produce extra data */ |
| 105 | adns__qtf_mail822= 0x20000, /* make mailboxes be in RFC822 rcpt field format */ |
| 106 | |
| 107 | adns_r_none= 0, |
| 108 | |
| 109 | adns_r_a= 1, |
| 110 | |
| 111 | adns_r_ns_raw= 2, |
| 112 | adns_r_ns= adns_r_ns_raw|adns__qtf_deref, |
| 113 | |
| 114 | adns_r_cname= 5, |
| 115 | |
| 116 | adns_r_soa_raw= 6, |
| 117 | adns_r_soa= adns_r_soa_raw|adns__qtf_mail822, |
| 118 | |
| 119 | adns_r_ptr_raw= 12, |
| 120 | adns_r_ptr= adns_r_ptr_raw|adns__qtf_deref, |
| 121 | |
| 122 | adns_r_hinfo= 13, |
| 123 | |
| 124 | adns_r_mx_raw= 15, |
| 125 | adns_r_mx= adns_r_mx_raw|adns__qtf_deref, |
| 126 | |
| 127 | adns_r_txt= 16, |
| 128 | |
| 129 | adns_r_rp_raw= 17, |
| 130 | adns_r_rp= adns_r_rp_raw|adns__qtf_mail822, |
| 131 | |
| 132 | adns_r_addr= adns_r_a|adns__qtf_deref |
| 133 | |
| 134 | } adns_rrtype; |
| 135 | |
| 136 | /* |
| 137 | * In queries without qf_quoteok_*, all domains must have standard |
| 138 | * legal syntax, or you get adns_s_querydomainvalid (if the query |
| 139 | * domain contains bad characters) or adns_s_answerdomaininvalid (if |
| 140 | * the answer contains bad characters). |
| 141 | * |
| 142 | * In queries _with_ qf_quoteok_*, domains in the query or response |
| 143 | * may contain any characters, quoted according to RFC1035 5.1. On |
| 144 | * input to adns, the char* is a pointer to the interior of a " |
| 145 | * delimited string, except that " may appear in it, and on output, |
| 146 | * the char* is a pointer to a string which would be legal either |
| 147 | * inside or outside " delimiters, and any characters not usually |
| 148 | * legal in domain names will be quoted as \X (if the character is |
| 149 | * 33-126 except \ and ") or \DDD. |
| 150 | * |
| 151 | * If the query goes via a CNAME then the canonical name (ie, the |
| 152 | * thing that the CNAME record refers to) is usually allowed to |
| 153 | * contain any characters, which will be quoted as above. With |
| 154 | * adns_qf_quotefail_cname you get adns_s_answerdomaininvalid when |
| 155 | * this happens. (This is a change from version 0.4 and earlier, in |
| 156 | * which failing the query was the default, and you had to say |
| 157 | * adns_qf_quoteok_cname to avoid this; that flag is now deprecated.) |
| 158 | * |
| 159 | * In version 0.4 and earlier, asking for _raw records containing |
| 160 | * mailboxes without specifying _qf_quoteok_anshost was silly. This |
| 161 | * is no longer the case. In this version only parts of responses |
| 162 | * that are actually supposed to be hostnames will be refused by |
| 163 | * default if quote-requiring characters are found. |
| 164 | */ |
| 165 | |
| 166 | /* |
| 167 | * If you ask for an RR which contains domains which are actually |
| 168 | * encoded mailboxes, and don't ask for the _raw version, then adns |
| 169 | * returns the mailbox formatted suitably for an RFC822 recipient |
| 170 | * header field. The particular format used is that if the mailbox |
| 171 | * requires quoting according to the rules in RFC822 then the |
| 172 | * local-part is quoted in double quotes, which end at the next |
| 173 | * unescaped double quote. (\ is the escape char, and is doubled, and |
| 174 | * is used to escape only \ and ".) Otherwise the local-part is |
| 175 | * presented as-is. In any case this is followed by an @ and the |
| 176 | * domain. The domain will not contain any characters not legal in |
| 177 | * hostnames. adns will protect the application from local parts |
| 178 | * containing control characters - these appear to be legal according |
| 179 | * to RFC822 but are clearly a bad idea. |
| 180 | * |
| 181 | * If you ask for the domain with _raw then _no_ checking is done |
| 182 | * (even on the host part, regardless of adns_qf_quoteok_anshost), and |
| 183 | * you just get the domain name in master file format. |
| 184 | * |
| 185 | * If no mailbox is supplied the returned string will be `.' in either |
| 186 | * caswe. |
| 187 | */ |
| 188 | |
| 189 | typedef enum { |
| 190 | adns_s_ok, |
| 191 | |
| 192 | /* locally induced errors */ |
| 193 | adns_s_nomemory, |
| 194 | adns_s_unknownrrtype, |
| 195 | adns_s_systemfail, |
| 196 | |
| 197 | adns_s_max_localfail= 29, |
| 198 | |
| 199 | /* remotely induced errors, detected locally */ |
| 200 | adns_s_timeout, |
| 201 | adns_s_allservfail, |
| 202 | adns_s_norecurse, |
| 203 | adns_s_invalidresponse, |
| 204 | adns_s_unknownformat, |
| 205 | |
| 206 | adns_s_max_remotefail= 59, |
| 207 | |
| 208 | /* remotely induced errors, reported by remote server to us */ |
| 209 | adns_s_rcodeservfail, |
| 210 | adns_s_rcodeformaterror, |
| 211 | adns_s_rcodenotimplemented, |
| 212 | adns_s_rcoderefused, |
| 213 | adns_s_rcodeunknown, |
| 214 | |
| 215 | adns_s_max_tempfail= 99, |
| 216 | |
| 217 | /* remote configuration errors */ |
| 218 | adns_s_inconsistent, /* PTR gives domain whose A does not exist and match */ |
| 219 | adns_s_prohibitedcname, /* CNAME found where eg A expected (not if _qf_loosecname) */ |
| 220 | adns_s_answerdomaininvalid, |
| 221 | adns_s_answerdomaintoolong, |
| 222 | adns_s_invaliddata, |
| 223 | |
| 224 | adns_s_max_misconfig= 199, |
| 225 | |
| 226 | /* permanent problems with the query */ |
| 227 | adns_s_querydomainwrong, |
| 228 | adns_s_querydomaininvalid, |
| 229 | adns_s_querydomaintoolong, |
| 230 | |
| 231 | adns_s_max_misquery= 299, |
| 232 | |
| 233 | /* permanent errors */ |
| 234 | adns_s_nxdomain, |
| 235 | adns_s_nodata, |
| 236 | |
| 237 | adns_s_max_permfail= 499 |
| 238 | |
| 239 | } adns_status; |
| 240 | |
| 241 | typedef struct { |
| 242 | int len; |
| 243 | union { |
| 244 | struct sockaddr sa; |
| 245 | struct sockaddr_in inet; |
| 246 | } addr; |
| 247 | } adns_rr_addr; |
| 248 | |
| 249 | typedef struct { |
| 250 | char *host; |
| 251 | adns_status astatus; |
| 252 | int naddrs; /* temp fail => -1, perm fail => 0, s_ok => >0 */ |
| 253 | adns_rr_addr *addrs; |
| 254 | } adns_rr_hostaddr; |
| 255 | |
| 256 | typedef struct { |
| 257 | char *(array[2]); |
| 258 | } adns_rr_strpair; |
| 259 | |
| 260 | typedef struct { |
| 261 | int i; |
| 262 | adns_rr_hostaddr ha; |
| 263 | } adns_rr_inthostaddr; |
| 264 | |
| 265 | typedef struct { |
| 266 | /* Used both for mx_raw, in which case i is the preference and str the domain, |
| 267 | * and for txt, in which case each entry has i for the `text' length, |
| 268 | * and str for the data (which will have had an extra nul appended |
| 269 | * so that if it was plain text it is now a null-terminated string). |
| 270 | */ |
| 271 | int i; |
| 272 | char *str; |
| 273 | } adns_rr_intstr; |
| 274 | |
| 275 | typedef struct { |
| 276 | adns_rr_intstr array[2]; |
| 277 | } adns_rr_intstrpair; |
| 278 | |
| 279 | typedef struct { |
| 280 | char *mname, *rname; |
| 281 | unsigned long serial, refresh, retry, expire, minimum; |
| 282 | } adns_rr_soa; |
| 283 | |
| 284 | typedef struct { |
| 285 | adns_status status; |
| 286 | char *cname; /* always NULL if query was for CNAME records */ |
| 287 | char *owner; /* only set if requested in query flags */ |
| 288 | adns_rrtype type; /* guaranteed to be same as in query */ |
| 289 | time_t expires; /* expiry time, defined only if _s_ok, nxdomain or nodata. NOT TTL! */ |
| 290 | int nrrs, rrsz; /* nrrs is 0 if an error occurs */ |
| 291 | union { |
| 292 | void *untyped; |
| 293 | unsigned char *bytes; |
| 294 | char *(*str); /* ns_raw, cname, ptr, ptr_raw */ |
| 295 | adns_rr_intstr *(*manyistr); /* txt (list of strings ends with i=-1, str=0) */ |
| 296 | adns_rr_addr *addr; /* addr */ |
| 297 | struct in_addr *inaddr; /* a */ |
| 298 | adns_rr_hostaddr *hostaddr; /* ns */ |
| 299 | adns_rr_intstrpair *intstrpair; /* hinfo */ |
| 300 | adns_rr_strpair *strpair; /* rp, rp_raw */ |
| 301 | adns_rr_inthostaddr *inthostaddr; /* mx */ |
| 302 | adns_rr_intstr *intstr; /* mx_raw */ |
| 303 | adns_rr_soa *soa; /* soa, soa_raw */ |
| 304 | } rrs; |
| 305 | } adns_answer; |
| 306 | |
| 307 | /* Memory management: |
| 308 | * adns_state and adns_query are actually pointers to malloc'd state; |
| 309 | * On submission questions are copied, including the owner domain; |
| 310 | * Answers are malloc'd as a single piece of memory; pointers in the |
| 311 | * answer struct point into further memory in the answer. |
| 312 | * query_io: |
| 313 | * Must always be non-null pointer; |
| 314 | * If *query_io is 0 to start with then any query may be returned; |
| 315 | * If *query_io is !0 adns_query then only that query may be returned. |
| 316 | * If the call is successful, *query_io, *answer_r, and *context_r |
| 317 | * will all be set. |
| 318 | * Errors: |
| 319 | * Return values are 0 or an errno value. |
| 320 | * |
| 321 | * For _init, _init_strcfg, _submit and _synchronous, system errors |
| 322 | * (eg, failure to create sockets, malloc failure, etc.) return errno |
| 323 | * values. |
| 324 | * |
| 325 | * For _wait and _check failures are reported in the answer |
| 326 | * structure, and only 0, ESRCH or (for _check) EAGAIN is |
| 327 | * returned: if no (appropriate) requests are done adns_check returns |
| 328 | * EAGAIN; if no (appropriate) requests are outstanding both |
| 329 | * adns_query and adns_wait return ESRCH. |
| 330 | * |
| 331 | * Additionally, _wait can return EINTR if you set adns_if_eintr. |
| 332 | * |
| 333 | * All other errors (nameserver failure, timed out connections, &c) |
| 334 | * are returned in the status field of the answer. After a |
| 335 | * successful _wait or _check, if status is nonzero then nrrs will be |
| 336 | * 0, otherwise it will be >0. type will always be the type |
| 337 | * requested. |
| 338 | */ |
| 339 | |
| 340 | int adns_init(adns_state *newstate_r, adns_initflags flags, |
| 341 | FILE *diagfile /*0=>stderr*/); |
| 342 | |
| 343 | int adns_init_strcfg(adns_state *newstate_r, adns_initflags flags, |
| 344 | FILE *diagfile /*0=>discard*/, const char *configtext); |
| 345 | |
| 346 | /* Configuration: |
| 347 | * adns_init reads /etc/resolv.conf, which is expected to be (broadly |
| 348 | * speaking) in the format expected by libresolv. adns_init_strcfg |
| 349 | * is instead passed a string which is interpreted as if it were the |
| 350 | * contents of resolv.conf. In general, configuration which is set |
| 351 | * later overrides any that is set earlier. |
| 352 | * |
| 353 | * Standard directives understood in resolv.conf: |
| 354 | * |
| 355 | * nameserver <address> |
| 356 | * Must be followed by the IP address of a nameserver. Several |
| 357 | * nameservers may be specified, and they will be tried in the order |
| 358 | * found. There is a compiled in limit, currently 5, on the number |
| 359 | * of nameservers. (libresolv supports only 3 nameservers.) |
| 360 | * |
| 361 | * search <domain> ... |
| 362 | * Specifies the search list for queries which specify |
| 363 | * adns_qf_search. This is a list of domains to append to the query |
| 364 | * domain. The query domain will be tried as-is either before all |
| 365 | * of these or after them, depending on the ndots option setting |
| 366 | * (see below). |
| 367 | * |
| 368 | * domain <domain> |
| 369 | * This is present only for backward compatibility with obsolete |
| 370 | * versions of libresolv. It should not be used, and is interpreted |
| 371 | * by adns as if it were `search' - note that this is subtly |
| 372 | * different to libresolv's interpretation of this directive. |
| 373 | * |
| 374 | * sortlist <addr>/<mask> ... |
| 375 | * Should be followed by a sequence of IP-address and netmask pairs, |
| 376 | * separated by spaces. They may be specified as |
| 377 | * eg. 172.30.206.0/24 or 172.30.206.0/255.255.255.0. Currently up |
| 378 | * to 15 pairs may be specified (but note that libresolv only |
| 379 | * supports up to 10). |
| 380 | * |
| 381 | * options |
| 382 | * Should followed by one or more options, separated by spaces. |
| 383 | * Each option consists of an option name, followed by optionally |
| 384 | * a colon and a value. Options are listed below. |
| 385 | * |
| 386 | * Non-standard directives understood in resolv.conf: |
| 387 | * |
| 388 | * clearnameservers |
| 389 | * Clears the list of nameservers, so that further nameserver lines |
| 390 | * start again from the beginning. |
| 391 | * |
| 392 | * include <filename> |
| 393 | * The specified file will be read. |
| 394 | * |
| 395 | * Additionally, adns will ignore lines in resolv.conf which start with a #. |
| 396 | * |
| 397 | * Standard options understood: |
| 398 | * |
| 399 | * debug |
| 400 | * Enables debugging output from the resolver, which will be written |
| 401 | * to stderr. |
| 402 | * |
| 403 | * ndots:<count> |
| 404 | * Affects whether queries with adns_qf_search will be tried first |
| 405 | * without adding domains from the searchlist, or whether the bare |
| 406 | * query domain will be tried last. Queries which contain at least |
| 407 | * <count> dots will be tried bare first. The default is 1. |
| 408 | * |
| 409 | * Non-standard options understood: |
| 410 | * |
| 411 | * adns_checkc:none |
| 412 | * adns_checkc:entex |
| 413 | * adns_checkc:freq |
| 414 | * Changes the consistency checking frequency; this overrides the |
| 415 | * setting of adns_if_check_entex, adns_if_check_freq, or neither, |
| 416 | * in the flags passed to adns_init. |
| 417 | * |
| 418 | * There are a number of environment variables which can modify the |
| 419 | * behaviour of adns. They take effect only if adns_init is used, and |
| 420 | * the caller of adns_init can disable them using adns_if_noenv. In |
| 421 | * each case there is both a FOO and an ADNS_FOO; the latter is |
| 422 | * interpreted later so that it can override the former. Unless |
| 423 | * otherwise stated, environment variables are interpreted after |
| 424 | * resolv.conf is read, in the order they are listed here. |
| 425 | * |
| 426 | * RES_CONF, ADNS_RES_CONF |
| 427 | * A filename, whose contets are in the format of resolv.conf. |
| 428 | * |
| 429 | * RES_CONF_TEXT, ADNS_RES_CONF_TEXT |
| 430 | * A string in the format of resolv.conf. |
| 431 | * |
| 432 | * RES_OPTIONS, ADNS_RES_OPTIONS |
| 433 | * These are parsed as if they appeared in the `options' line of a |
| 434 | * resolv.conf. In addition to being parsed at this point in the |
| 435 | * sequence, they are also parsed at the very beginning before |
| 436 | * resolv.conf or any other environment variables are read, so that |
| 437 | * any debug option can affect the processing of the configuration. |
| 438 | * |
| 439 | * LOCALDOMAIN, ADNS_LOCALDOMAIN |
| 440 | * These are interpreted as if their contents appeared in a `search' |
| 441 | * line in resolv.conf. |
| 442 | */ |
| 443 | |
| 444 | int adns_synchronous(adns_state ads, |
| 445 | const char *owner, |
| 446 | adns_rrtype type, |
| 447 | adns_queryflags flags, |
| 448 | adns_answer **answer_r); |
| 449 | |
| 450 | /* NB: if you set adns_if_noautosys then _submit and _check do not |
| 451 | * make any system calls; you must use some of the asynch-io event |
| 452 | * processing functions to actually get things to happen. |
| 453 | */ |
| 454 | |
| 455 | int adns_submit(adns_state ads, |
| 456 | const char *owner, |
| 457 | adns_rrtype type, |
| 458 | adns_queryflags flags, |
| 459 | void *context, |
| 460 | adns_query *query_r); |
| 461 | |
| 462 | /* The owner should be quoted in master file format. */ |
| 463 | |
| 464 | int adns_check(adns_state ads, |
| 465 | adns_query *query_io, |
| 466 | adns_answer **answer_r, |
| 467 | void **context_r); |
| 468 | |
| 469 | int adns_wait(adns_state ads, |
| 470 | adns_query *query_io, |
| 471 | adns_answer **answer_r, |
| 472 | void **context_r); |
| 473 | |
| 474 | /* same as adns_wait but uses poll(2) internally */ |
| 475 | int adns_wait_poll(adns_state ads, |
| 476 | adns_query *query_io, |
| 477 | adns_answer **answer_r, |
| 478 | void **context_r); |
| 479 | |
| 480 | void adns_cancel(adns_query query); |
| 481 | |
| 482 | /* The adns_query you get back from _submit is valid (ie, can be |
| 483 | * legitimately passed into adns functions) until it is returned by |
| 484 | * adns_check or adns_wait, or passed to adns_cancel. After that it |
| 485 | * must not be used. You can rely on it not being reused until the |
| 486 | * first adns_submit or _transact call using the same adns_state after |
| 487 | * it became invalid, so you may compare it for equality with other |
| 488 | * query handles until you next call _query or _transact. |
| 489 | * |
| 490 | * _submit and _synchronous return ENOSYS if they don't understand the |
| 491 | * query type. |
| 492 | */ |
| 493 | |
| 494 | int adns_submit_reverse(adns_state ads, |
| 495 | const struct sockaddr *addr, |
| 496 | adns_rrtype type, |
| 497 | adns_queryflags flags, |
| 498 | void *context, |
| 499 | adns_query *query_r); |
| 500 | /* type must be _r_ptr or _r_ptr_raw. _qf_search is ignored. |
| 501 | * addr->sa_family must be AF_INET or you get ENOSYS. |
| 502 | */ |
| 503 | |
| 504 | void adns_finish(adns_state ads); |
| 505 | /* You may call this even if you have queries outstanding; |
| 506 | * they will be cancelled. |
| 507 | */ |
| 508 | |
| 509 | |
| 510 | void adns_forallqueries_begin(adns_state ads); |
| 511 | adns_query adns_forallqueries_next(adns_state ads, void **context_r); |
| 512 | /* Iterator functions, which you can use to loop over the outstanding |
| 513 | * (submitted but not yet successfuly checked/waited) queries. |
| 514 | * |
| 515 | * You can only have one iteration going at once. You may call _begin |
| 516 | * at any time; after that, an iteration will be in progress. You may |
| 517 | * only call _next when an iteration is in progress - anything else |
| 518 | * may coredump. The iteration remains in progress until _next |
| 519 | * returns 0, indicating that all the queries have been walked over, |
| 520 | * or ANY other adns function is called with the same adns_state (or a |
| 521 | * query in the same adns_state). There is no need to explicitly |
| 522 | * finish an iteration. |
| 523 | * |
| 524 | * context_r may be 0. *context_r may not be set when _next returns 0. |
| 525 | */ |
| 526 | |
| 527 | void adns_checkconsistency(adns_state ads, adns_query qu); |
| 528 | /* Checks the consistency of adns's internal data structures. |
| 529 | * If any error is found, the program will abort(). |
| 530 | * You may pass 0 for qu; if you pass non-null then additional checks |
| 531 | * are done to make sure that qu is a valid query. |
| 532 | */ |
| 533 | |
| 534 | /* |
| 535 | * Example expected/legal calling sequence for submit/check/wait: |
| 536 | * adns_init |
| 537 | * adns_submit 1 |
| 538 | * adns_submit 2 |
| 539 | * adns_submit 3 |
| 540 | * adns_wait 1 |
| 541 | * adns_check 3 -> EAGAIN |
| 542 | * adns_wait 2 |
| 543 | * adns_wait 3 |
| 544 | * .... |
| 545 | * adns_finish |
| 546 | */ |
| 547 | |
| 548 | /* |
| 549 | * Entrypoints for generic asynch io: |
| 550 | * (these entrypoints are not very useful except in combination with * |
| 551 | * some of the other I/O model calls which can tell you which fds to |
| 552 | * be interested in): |
| 553 | * |
| 554 | * Note that any adns call may cause adns to open and close fds, so |
| 555 | * you must call beforeselect or beforepoll again just before |
| 556 | * blocking, or you may not have an up-to-date list of it's fds. |
| 557 | */ |
| 558 | |
| 559 | int adns_processany(adns_state ads); |
| 560 | /* Gives adns flow-of-control for a bit. This will never block, and |
| 561 | * can be used with any threading/asynch-io model. If some error |
| 562 | * occurred which might cause an event loop to spin then the errno |
| 563 | * value is returned. |
| 564 | */ |
| 565 | |
| 566 | int adns_processreadable(adns_state ads, int fd, const struct timeval *now); |
| 567 | int adns_processwriteable(adns_state ads, int fd, const struct timeval *now); |
| 568 | int adns_processexceptional(adns_state ads, int fd, const struct timeval *now); |
| 569 | /* Gives adns flow-of-control so that it can process incoming data |
| 570 | * from, or send outgoing data via, fd. Very like _processany. If it |
| 571 | * returns zero then fd will no longer be readable or writeable |
| 572 | * (unless of course more data has arrived since). adns will _only_ |
| 573 | * use that fd and only in the manner specified, regardless of whether |
| 574 | * adns_if_noautosys was specified. |
| 575 | * |
| 576 | * adns_processexceptional should be called when select(2) reports an |
| 577 | * exceptional condition, or poll(2) reports POLLPRI. |
| 578 | * |
| 579 | * It is fine to call _processreabable or _processwriteable when the |
| 580 | * fd is not ready, or with an fd that doesn't belong to adns; it will |
| 581 | * then just return 0. |
| 582 | * |
| 583 | * If some error occurred which might prevent an event loop to spin |
| 584 | * then the errno value is returned. |
| 585 | */ |
| 586 | |
| 587 | void adns_processtimeouts(adns_state ads, const struct timeval *now); |
| 588 | /* Gives adns flow-of-control so that it can process any timeouts |
| 589 | * which might have happened. Very like _processreadable/writeable. |
| 590 | * |
| 591 | * now may be 0; if it isn't, *now must be the current time, recently |
| 592 | * obtained from gettimeofday. |
| 593 | */ |
| 594 | |
| 595 | void adns_firsttimeout(adns_state ads, |
| 596 | struct timeval **tv_mod, struct timeval *tv_buf, |
| 597 | struct timeval now); |
| 598 | /* Asks adns when it would first like the opportunity to time |
| 599 | * something out. now must be the current time, from gettimeofday. |
| 600 | * |
| 601 | * If tv_mod points to 0 then tv_buf must be non-null, and |
| 602 | * _firsttimeout will fill in *tv_buf with the time until the first |
| 603 | * timeout, and make *tv_mod point to tv_buf. If adns doesn't have |
| 604 | * anything that might need timing out it will leave *tv_mod as 0. |
| 605 | * |
| 606 | * If *tv_mod is not 0 then tv_buf is not used. adns will update |
| 607 | * *tv_mod if it has any earlier timeout, and leave it alone if it |
| 608 | * doesn't. |
| 609 | * |
| 610 | * This call will not actually do any I/O, or change the fds that adns |
| 611 | * is using. It always succeeds and never blocks. |
| 612 | */ |
| 613 | |
| 614 | void adns_globalsystemfailure(adns_state ads); |
| 615 | /* If serious problem(s) happen which globally affect your ability to |
| 616 | * interact properly with adns, or adns's ability to function |
| 617 | * properly, you or adns can call this function. |
| 618 | * |
| 619 | * All currently outstanding queries will be made to fail with |
| 620 | * adns_s_systemfail, and adns will close any stream sockets it has |
| 621 | * open. |
| 622 | * |
| 623 | * This is used by adns, for example, if gettimeofday() fails. |
| 624 | * Without this the program's event loop might start to spin ! |
| 625 | * |
| 626 | * This call will never block. |
| 627 | */ |
| 628 | |
| 629 | /* |
| 630 | * Entrypoints for select-loop based asynch io: |
| 631 | */ |
| 632 | |
| 633 | void adns_beforeselect(adns_state ads, int *maxfd, fd_set *readfds, |
| 634 | fd_set *writefds, fd_set *exceptfds, |
| 635 | struct timeval **tv_mod, struct timeval *tv_buf, |
| 636 | const struct timeval *now); |
| 637 | /* Find out file descriptors adns is interested in, and when it would |
| 638 | * like the opportunity to time something out. If you do not plan to |
| 639 | * block then tv_mod may be 0. Otherwise, tv_mod and tv_buf are as |
| 640 | * for adns_firsttimeout. readfds, writefds, exceptfds and maxfd_io may |
| 641 | * not be 0. |
| 642 | * |
| 643 | * If *now is not 0 then this will never actually do any I/O, or |
| 644 | * change the fds that adns is using or the timeouts it wants. In any |
| 645 | * case it won't block. |
| 646 | */ |
| 647 | |
| 648 | void adns_afterselect(adns_state ads, int maxfd, const fd_set *readfds, |
| 649 | const fd_set *writefds, const fd_set *exceptfds, |
| 650 | const struct timeval *now); |
| 651 | /* Gives adns flow-of-control for a bit; intended for use after |
| 652 | * select. This is just a fancy way of calling adns_processreadable/ |
| 653 | * writeable/timeouts as appropriate, as if select had returned the |
| 654 | * data being passed. Always succeeds. |
| 655 | */ |
| 656 | |
| 657 | /* |
| 658 | * Example calling sequence: |
| 659 | * |
| 660 | * adns_init _noautosys |
| 661 | * loop { |
| 662 | * adns_beforeselect |
| 663 | * select |
| 664 | * adns_afterselect |
| 665 | * ... |
| 666 | * adns_submit / adns_check |
| 667 | * ... |
| 668 | * } |
| 669 | */ |
| 670 | |
| 671 | /* |
| 672 | * Entrypoints for poll-loop based asynch io: |
| 673 | */ |
| 674 | |
| 675 | struct pollfd; |
| 676 | /* In case your system doesn't have it or you forgot to include |
| 677 | * <sys/poll.h>, to stop the following declarations from causing |
| 678 | * problems. If your system doesn't have poll then the following |
| 679 | * entrypoints will not be defined in libadns. Sorry ! |
| 680 | */ |
| 681 | |
| 682 | int adns_beforepoll(adns_state ads, struct pollfd *fds, int *nfds_io, int *timeout_io, |
| 683 | const struct timeval *now); |
| 684 | /* Finds out which fd's adns is interested in, and when it would like |
| 685 | * to be able to time things out. This is in a form suitable for use |
| 686 | * with poll(2). |
| 687 | * |
| 688 | * On entry, usually fds should point to at least *nfds_io structs. |
| 689 | * adns will fill up to that many structs will information for poll, |
| 690 | * and record in *nfds_io how many structs it filled. If it wants to |
| 691 | * listen for more structs then *nfds_io will be set to the number |
| 692 | * required and _beforepoll will return ERANGE. |
| 693 | * |
| 694 | * You may call _beforepoll with fds==0 and *nfds_io 0, in which case |
| 695 | * adns will fill in the number of fds that it might be interested in |
| 696 | * in *nfds_io, and always return either 0 (if it is not interested in |
| 697 | * any fds) or ERANGE (if it is). |
| 698 | * |
| 699 | * NOTE that (unless now is 0) adns may acquire additional fds |
| 700 | * from one call to the next, so you must put adns_beforepoll in a |
| 701 | * loop, rather than assuming that the second call (with the buffer |
| 702 | * size requested by the first) will not return ERANGE. |
| 703 | * |
| 704 | * adns only ever sets POLLIN, POLLOUT and POLLPRI in its pollfd |
| 705 | * structs, and only ever looks at those bits. POLLPRI is required to |
| 706 | * detect TCP Urgent Data (which should not be used by a DNS server) |
| 707 | * so that adns can know that the TCP stream is now useless. |
| 708 | * |
| 709 | * In any case, *timeout_io should be a timeout value as for poll(2), |
| 710 | * which adns will modify downwards as required. If the caller does |
| 711 | * not plan to block then *timeout_io should be 0 on entry, or |
| 712 | * alternatively, timeout_io may be 0. (Alternatively, the caller may |
| 713 | * use _beforeselect with timeout_io==0 to find out about file |
| 714 | * descriptors, and use _firsttimeout is used to find out when adns |
| 715 | * might want to time something out.) |
| 716 | * |
| 717 | * adns_beforepoll will return 0 on success, and will not fail for any |
| 718 | * reason other than the fds buffer being too small (ERANGE). |
| 719 | * |
| 720 | * This call will never actually do any I/O. If you supply the |
| 721 | * current time it will not change the fds that adns is using or the |
| 722 | * timeouts it wants. |
| 723 | * |
| 724 | * In any case this call won't block. |
| 725 | */ |
| 726 | |
| 727 | #define ADNS_POLLFDS_RECOMMENDED 2 |
| 728 | /* If you allocate an fds buf with at least RECOMMENDED entries then |
| 729 | * you are unlikely to need to enlarge it. You are recommended to do |
| 730 | * so if it's convenient. However, you must be prepared for adns to |
| 731 | * require more space than this. |
| 732 | */ |
| 733 | |
| 734 | void adns_afterpoll(adns_state ads, const struct pollfd *fds, int nfds, |
| 735 | const struct timeval *now); |
| 736 | /* Gives adns flow-of-control for a bit; intended for use after |
| 737 | * poll(2). fds and nfds should be the results from poll(). pollfd |
| 738 | * structs mentioning fds not belonging to adns will be ignored. |
| 739 | */ |
| 740 | |
| 741 | |
| 742 | adns_status adns_rr_info(adns_rrtype type, |
| 743 | const char **rrtname_r, const char **fmtname_r, |
| 744 | int *len_r, |
| 745 | const void *datap, char **data_r); |
| 746 | /* |
| 747 | * Get information about a query type, or convert reply data to a |
| 748 | * textual form. type must be specified, and the official name of the |
| 749 | * corresponding RR type will be returned in *rrtname_r, and |
| 750 | * information about the processing style in *fmtname_r. The length |
| 751 | * of the table entry in an answer for that type will be returned in |
| 752 | * in *len_r. Any or all of rrtname_r, fmtname_r and len_r may be 0. |
| 753 | * If fmtname_r is non-null then *fmtname_r may be null on return, |
| 754 | * indicating that no special processing is involved. |
| 755 | * |
| 756 | * data_r be must be non-null iff datap is. In this case *data_r will |
| 757 | * be set to point to a string pointing to a representation of the RR |
| 758 | * data in master file format. (The owner name, timeout, class and |
| 759 | * type will not be present - only the data part of the RR.) The |
| 760 | * memory will have been obtained from malloc() and must be freed by |
| 761 | * the caller. |
| 762 | * |
| 763 | * Usually this routine will succeed. Possible errors include: |
| 764 | * adns_s_nomemory |
| 765 | * adns_s_rrtypeunknown |
| 766 | * adns_s_invaliddata (*datap contained garbage) |
| 767 | * If an error occurs then no memory has been allocated, |
| 768 | * and *rrtname_r, *fmtname_r, *len_r and *data_r are undefined. |
| 769 | * |
| 770 | * There are some adns-invented data formats which are not official |
| 771 | * master file formats. These include: |
| 772 | * |
| 773 | * Mailboxes if __qtf_mail822: these are just included as-is. |
| 774 | * |
| 775 | * Addresses (adns_rr_addr): these may be of pretty much any type. |
| 776 | * The representation is in two parts: first, a word for the address |
| 777 | * family (ie, in AF_XXX, the XXX), and then one or more items for the |
| 778 | * address itself, depending on the format. For an IPv4 address the |
| 779 | * syntax is INET followed by the dotted quad (from inet_ntoa). |
| 780 | * Currently only IPv4 is supported. |
| 781 | * |
| 782 | * Text strings (as in adns_rr_txt) appear inside double quotes, and |
| 783 | * use \" and \\ to represent " and \, and \xHH to represent |
| 784 | * characters not in the range 32-126. |
| 785 | * |
| 786 | * Hostname with addresses (adns_rr_hostaddr): this consists of the |
| 787 | * hostname, as usual, followed by the adns_status value, as an |
| 788 | * abbreviation, and then a descriptive string (encoded as if it were |
| 789 | * a piece of text), for the address lookup, followed by zero or more |
| 790 | * addresses enclosed in ( and ). If the result was a permanent |
| 791 | * failure, then a single ? appears instead of the ( ). If the |
| 792 | * result was a temporary failure then an empty pair of parentheses |
| 793 | * appears (which a space in between). For example, one of the NS |
| 794 | * records for greenend.org.uk comes out like |
| 795 | * ns.chiark.greenend.org.uk ok "OK" ( INET 195.224.76.132 ) |
| 796 | * an MX referring to a nonexistent host might come out like: |
| 797 | * 50 sun2.nsfnet-relay.ac.uk nxdomain "No such domain" ( ) |
| 798 | * and if nameserver information is not available you might get: |
| 799 | * dns2.spong.dyn.ml.org timeout "DNS query timed out" ? |
| 800 | */ |
| 801 | |
| 802 | const char *adns_strerror(adns_status st); |
| 803 | const char *adns_errabbrev(adns_status st); |
| 804 | const char *adns_errtypeabbrev(adns_status st); |
| 805 | /* Like strerror but for adns_status values. adns_errabbrev returns |
| 806 | * the abbreviation of the error - eg, for adns_s_timeout it returns |
| 807 | * "timeout". adns_errtypeabbrev returns the abbreviation of the |
| 808 | * error class: ie, for values up to adns_s_max_XXX it will return the |
| 809 | * string XXX. You MUST NOT call these functions with status values |
| 810 | * not returned by the same adns library. |
| 811 | */ |
| 812 | |
| 813 | #ifdef __cplusplus |
| 814 | } /* end of extern "C" */ |
| 815 | #endif |
| 816 | #endif |