3 * - declarations of private objects with external linkage (adns__*)
4 * - definitons of internal macros
5 * - comments regarding library data structures
9 * Copyright (C) 1997-1999 Ian Jackson <ian@davenant.greenend.org.uk>
11 * It is part of adns, which is
12 * Copyright (C) 1997-1999 Ian Jackson <ian@davenant.greenend.org.uk>
13 * Copyright (C) 1999 Tony Finch <dot@dotat.at>
15 * This program is free software; you can redistribute it and/or modify
16 * it under the terms of the GNU General Public License as published by
17 * the Free Software Foundation; either version 2, or (at your option)
20 * This program is distributed in the hope that it will be useful,
21 * but WITHOUT ANY WARRANTY; without even the implied warranty of
22 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
23 * GNU General Public License for more details.
25 * You should have received a copy of the GNU General Public License
26 * along with this program; if not, write to the Free Software Foundation,
27 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
30 #ifndef ADNS_INTERNAL_H_INCLUDED
31 #define ADNS_INTERNAL_H_INCLUDED
34 typedef unsigned char byte;
48 /* Configuration and constants */
51 #define MAXSORTLIST 15
52 #define UDPMAXRETRIES 15
53 #define UDPRETRYMS 2000
54 #define TCPWAITMS 30000
55 #define TCPCONNMS 14000
56 #define TCPIDLEMS 30000
57 #define MAXTTLBELIEVE (7*86400) /* any TTL > 7 days is capped */
60 #define DNS_MAXUDP 512
61 #define DNS_MAXDOMAIN 255
62 #define DNS_HDRSIZE 12
63 #define DNS_IDOFFSET 0
64 #define DNS_CLASS_IN 1
66 #define DNS_INADDR_ARPA "in-addr", "arpa"
68 #define MAX_POLLFDS ADNS_POLLFDS_RECOMMENDED
85 /* Shared data structures */
106 int dglen, nsstart, nscount, arcount;
116 void (*makefinal)(adns_query qu, void *data);
117 /* Change memory management of *data.
118 * Previously, used alloc_interim, now use alloc_final.
121 adns_status (*convstring)(vbuf *vb, const void *data);
122 /* Converts the RR data to a string representation in vbuf.
123 * vbuf will be appended to (it must have been initialised),
124 * and will not be null-terminated by convstring.
127 adns_status (*parse)(const parseinfo *pai, int cbyte, int max, void *store_r);
128 /* Parse one RR, in dgram of length dglen, starting at cbyte and
129 * extending until at most max.
131 * The RR should be stored at *store_r, of length qu->typei->rrsz.
133 * If there is an overrun which might indicate truncation, it should set
134 * *rdstart to -1; otherwise it may set it to anything else positive.
136 * nsstart is the offset of the authority section.
139 int (*diff_needswap)(adns_state ads, const void *datap_a, const void *datap_b);
140 /* Returns !0 if RR a should be strictly after RR b in the sort order,
141 * 0 otherwise. Must not fail.
145 typedef struct allocnode {
146 struct allocnode *next, *back;
160 void (*callback)(adns_query parent, adns_query child);
162 adns_rr_addr ptr_parent_addr;
163 adns_rr_hostaddr *hostaddr;
169 enum { query_tosend, query_tcpw, query_childw, query_done } state;
170 adns_query back, next, parent;
171 struct { adns_query head, tail; } children;
172 struct { adns_query back, next; } siblings;
173 struct { allocnode *head, *tail; } allocations;
174 int interim_allocd, preserved_allocd;
175 void *final_allocspace;
177 const typeinfo *typei;
182 /* General-purpose messing-about buffer.
183 * Wherever a `big' interface is crossed, this may be corrupted/changed
184 * unless otherwise specified.
188 /* This is allocated when a query is submitted, to avoid being unable
189 * to relate errors to queries if we run out of memory. During
190 * query processing status, rrs is 0. cname is set if
191 * we found a cname (this corresponds to cname_dgram in the query
192 * structure). type is set from the word go. nrrs and rrs
193 * are set together, when we find how many rrs there are.
194 * owner is set during querying unless we're doing searchlist,
195 * in which case it is set only when we find an answer.
199 int cname_dglen, cname_begin;
200 /* If non-0, has been allocated using . */
203 int search_origlen, search_pos, search_doneabs;
204 /* Used by the searching algorithm. The query domain in textual form
205 * is copied into the vbuf, and _origlen set to its length. Then
206 * we walk the searchlist, if we want to. _pos says where we are
207 * (next entry to try), and _doneabs says whether we've done the
208 * absolute query yet (0=not yet, 1=done, -1=must do straight away,
209 * but not done yet). If flags doesn't have adns_qf_search then
210 * the vbuf is initialised but empty and everything else is zero.
213 int id, flags, retries;
215 unsigned long udpsent; /* bitmap indexed by server */
216 struct timeval timeout;
217 time_t expires; /* Earliest expiry time of any record we used. */
223 * state Queue child id nextudpserver udpsent tcpfailed
225 * tosend NONE null >=0 0 zero zero
226 * tosend udpw null >=0 any nonzero zero
227 * tosend NONE null >=0 any nonzero zero
229 * tcpw tcpw null >=0 irrelevant any any
231 * child childw set >=0 irrelevant irrelevant irrelevant
232 * child NONE null >=0 irrelevant irrelevant irrelevant
233 * done output null -1 irrelevant irrelevant irrelevant
235 * Queries are only not on a queue when they are actually being processed.
236 * Queries in state tcpw/tcpw have been sent (or are in the to-send buffer)
237 * iff the tcp connection is in state server_ok.
239 * +------------------------+
240 * START -----> | tosend/NONE |
241 * +------------------------+
243 * too big for UDP / UDP timeout \ \ send via UDP
244 * send via TCP / more retries \ \
245 * when conn'd / desired \ \
248 * +-----------+ +-------------+
249 * | tcpw/tcpw | ________ | tosend/udpw |
250 * +-----------+ \ +-------------+
251 * | | | UDP timeout | |
254 * \ | TCP died | desired | |
256 * \ \ servers | TCP / |
257 * \ \ to try | timeout / |
259 * reply \ _| +------------------+ / reply
260 * \ | done/output FAIL | /
261 * \ +------------------+ /
264 * (..... got reply ....)
266 * need child query/ies / \ no child query
269 * +---------------+ +----------------+
270 * | childw/childw | ----------------> | done/output OK |
271 * +---------------+ children done +----------------+
275 struct query_queue { adns_query head, tail; };
278 adns_initflags iflags;
281 struct query_queue udpw, tcpw, childw, output;
282 adns_query forallnext;
283 int nextid, udpsocket, tcpsocket;
284 vbuf tcpsend, tcprecv;
285 int nservers, nsortlist, nsearchlist, searchndots, tcpserver, tcprecv_skip;
286 enum adns__tcpstate {
287 server_disconnected, server_connecting,
288 server_ok, server_broken
290 struct timeval tcptimeout;
291 /* This will have tv_sec==0 if it is not valid.
292 * It will always be valid if tcpstate _connecting.
293 * When _ok, it will be nonzero if we are idle
294 * (ie, tcpw queue is empty) and counting down.
296 struct sigaction stdsigpipe;
298 struct pollfd pollfds_buf[MAX_POLLFDS];
301 } servers[MAXSERVERS];
303 struct in_addr base, mask;
304 } sortlist[MAXSORTLIST];
310 int adns__setnonblock(adns_state ads, int fd); /* => errno value */
312 /* From general.c: */
314 void adns__vdiag(adns_state ads, const char *pfx, adns_initflags prevent,
315 int serv, adns_query qu, const char *fmt, va_list al);
317 void adns__debug(adns_state ads, int serv, adns_query qu,
318 const char *fmt, ...) PRINTFFORMAT(4,5);
319 void adns__warn(adns_state ads, int serv, adns_query qu,
320 const char *fmt, ...) PRINTFFORMAT(4,5);
321 void adns__diag(adns_state ads, int serv, adns_query qu,
322 const char *fmt, ...) PRINTFFORMAT(4,5);
324 int adns__vbuf_ensure(vbuf *vb, int want);
325 int adns__vbuf_appendstr(vbuf *vb, const char *data); /* does not include nul */
326 int adns__vbuf_append(vbuf *vb, const byte *data, int len);
327 /* 1=>success, 0=>realloc failed */
328 void adns__vbuf_appendq(vbuf *vb, const byte *data, int len);
329 void adns__vbuf_init(vbuf *vb);
330 void adns__vbuf_free(vbuf *vb);
332 const char *adns__diag_domain(adns_state ads, int serv, adns_query qu,
333 vbuf *vb, const byte *dgram, int dglen, int cbyte);
334 /* Unpicks a domain in a datagram and returns a string suitable for
335 * printing it as. Never fails - if an error occurs, it will
336 * return some kind of string describing the error.
338 * serv may be -1 and qu may be 0. vb must have been initialised,
339 * and will be left in an arbitrary consistent state.
341 * Returns either vb->buf, or a pointer to a string literal. Do not modify
342 * vb before using the return value.
345 void adns__isort(void *array, int nobjs, int sz, void *tempbuf,
346 int (*needswap)(void *context, const void *a, const void *b),
348 /* Does an insertion sort of array which must contain nobjs objects
349 * each sz bytes long. tempbuf must point to a buffer at least
350 * sz bytes long. needswap should return !0 if a>b (strictly, ie
351 * wrong order) 0 if a<=b (ie, order is fine).
354 void adns__sigpipe_protect(adns_state);
355 void adns__sigpipe_unprotect(adns_state);
356 /* If SIGPIPE protection is not disabled, will block all signals except
357 * SIGPIPE, and set SIGPIPE's disposition to SIG_IGN. (And then restore.)
358 * Each call to _protect must be followed by a call to _unprotect before
359 * any significant amount of code gets to run, since the old signal mask
360 * is stored in the adns structure.
363 /* From transmit.c: */
365 adns_status adns__mkquery(adns_state ads, vbuf *vb, int *id_r,
366 const char *owner, int ol,
367 const typeinfo *typei, adns_queryflags flags);
368 /* Assembles a query packet in vb. A new id is allocated and returned.
371 adns_status adns__mkquery_frdgram(adns_state ads, vbuf *vb, int *id_r,
372 const byte *qd_dgram, int qd_dglen, int qd_begin,
373 adns_rrtype type, adns_queryflags flags);
374 /* Same as adns__mkquery, but takes the owner domain from an existing datagram.
375 * That domain must be correct and untruncated.
378 void adns__querysend_tcp(adns_query qu, struct timeval now);
379 /* Query must be in state tcpw/tcpw; it will be sent if possible and
380 * no further processing can be done on it for now. The connection
381 * might be broken, but no reconnect will be attempted.
384 void adns__query_send(adns_query qu, struct timeval now);
385 /* Query must be in state tosend/NONE; it will be moved to a new state,
386 * and no further processing can be done on it for now.
387 * (Resulting state is one of udp/timew, tcpwait/timew (if server not connected),
388 * tcpsent/timew, child/childw or done/output.)
389 * __query_send may decide to use either UDP or TCP depending whether
390 * _qf_usevc is set (or has become set) and whether the query is too
396 adns_status adns__internal_submit(adns_state ads, adns_query *query_r,
397 const typeinfo *typei, vbuf *qumsg_vb, int id,
398 adns_queryflags flags, struct timeval now,
399 const qcontext *ctx);
400 /* Submits a query (for internal use, called during external submits).
402 * The new query is returned in *query_r, or we return adns_s_nomemory.
404 * The query datagram should already have been assembled in qumsg_vb;
405 * the memory for it is _taken over_ by this routine whether it
406 * succeeds or fails (if it succeeds, the vbuf is reused for qu->vb).
408 * *ctx is copied byte-for-byte into the query.
410 * When the child query is done, ctx->callback will be called. The
411 * child will already have been taken off both the global list of
412 * queries in ads and the list of children in the parent. The child
413 * will be freed when the callback returns. The parent will have been
414 * taken off the global childw queue.
416 * The callback should either call adns__query_done, if it is
417 * complete, or adns__query_fail, if an error has occurred, in which
418 * case the other children (if any) will be cancelled. If the parent
419 * has more unfinished children (or has just submitted more) then the
420 * callback may choose to wait for them - it must then put the parent
421 * back on the childw queue.
424 void adns__search_next(adns_state ads, adns_query qu, struct timeval now);
425 /* Walks down the searchlist for a query with adns_qf_search.
426 * The query should have just had a negative response, or not had
427 * any queries sent yet, and should not be on any queue.
428 * The query_dgram if any will be freed and forgotten and a new
429 * one constructed from the search_* members of the query.
431 * Cannot fail (in case of error, calls adns__query_fail).
434 void *adns__alloc_interim(adns_query qu, size_t sz);
435 void *adns__alloc_preserved(adns_query qu, size_t sz);
436 /* Allocates some memory, and records which query it came from
437 * and how much there was.
439 * If an error occurs in the query, all the memory from _interim is
440 * simply freed. If the query succeeds, one large buffer will be made
441 * which is big enough for all these allocations, and then
442 * adns__alloc_final will get memory from this buffer.
444 * _alloc_interim can fail (and return 0).
445 * The caller must ensure that the query is failed.
447 * The memory from _preserved is is kept and transferred into the
448 * larger buffer - unless we run out of memory, in which case it too
449 * is freed. When you use _preserved you have to add code to the
450 * x_nomem error exit case in adns__makefinal_query to clear out the
451 * pointers you made to those allocations, because that's when they're
452 * thrown away; you should also make a note in the declaration of
453 * those pointer variables, to note that they are _preserved rather
454 * than _interim. If they're in the answer, note it here:
455 * answer->cname and answer->owner are _preserved.
458 void adns__transfer_interim(adns_query from, adns_query to, void *block, size_t sz);
459 /* Transfers an interim allocation from one query to another, so that
460 * the `to' query will have room for the data when we get to makefinal
461 * and so that the free will happen when the `to' query is freed
462 * rather than the `from' query.
464 * It is legal to call adns__transfer_interim with a null pointer; this
467 * _transfer_interim also ensures that the expiry time of the `to' query
468 * is no later than that of the `from' query, so that child queries'
469 * TTLs get inherited by their parents.
472 void *adns__alloc_mine(adns_query qu, size_t sz);
473 /* Like _interim, but does not record the length for later
474 * copying into the answer. This just ensures that the memory
475 * will be freed when we're done with the query.
478 void *adns__alloc_final(adns_query qu, size_t sz);
479 /* Cannot fail, and cannot return 0.
482 void adns__makefinal_block(adns_query qu, void **blpp, size_t sz);
483 void adns__makefinal_str(adns_query qu, char **strp);
485 void adns__reset_preserved(adns_query qu);
486 /* Resets all of the memory management stuff etc. to take account of
487 * only the _preserved stuff from _alloc_preserved. Used when we find
488 * an error somewhere and want to just report the error (with perhaps
489 * CNAME, owner, etc. info), and also when we're halfway through RRs
490 * in a datagram and discover that we need to retry the query.
493 void adns__query_done(adns_query qu);
494 void adns__query_fail(adns_query qu, adns_status stat);
498 void adns__procdgram(adns_state ads, const byte *dgram, int len,
499 int serv, int viatcp, struct timeval now);
500 /* This function is allowed to cause new datagrams to be constructed
501 * and sent, or even new queries to be started. However,
502 * query-sending functions are not allowed to call any general event
503 * loop functions in case they accidentally call this.
505 * Ie, receiving functions may call sending functions.
506 * Sending functions may NOT call receiving functions.
511 const typeinfo *adns__findtype(adns_rrtype type);
520 int dglen, max, cbyte, namelen;
524 void adns__findlabel_start(findlabel_state *fls, adns_state ads,
525 int serv, adns_query qu,
526 const byte *dgram, int dglen, int max,
527 int dmbegin, int *dmend_rlater);
528 /* Finds labels in a domain in a datagram.
530 * Call this routine first.
531 * dmend_rlater may be null. ads (and of course fls) may not be.
532 * serv may be -1, qu may be null - they are for error reporting.
535 adns_status adns__findlabel_next(findlabel_state *fls, int *lablen_r, int *labstart_r);
536 /* Then, call this one repeatedly.
538 * It will return adns_s_ok if all is well, and tell you the length
539 * and start of successive labels. labstart_r may be null, but
540 * lablen_r must not be.
542 * After the last label, it will return with *lablen_r zero.
543 * Do not then call it again; instead, just throw away the findlabel_state.
545 * *dmend_rlater will have been set to point to the next part of
546 * the datagram after the label (or after the uncompressed part,
547 * if compression was used). *namelen_rlater will have been set
548 * to the length of the domain name (total length of labels plus
549 * 1 for each intervening dot).
551 * If the datagram appears to be truncated, *lablen_r will be -1.
552 * *dmend_rlater, *labstart_r and *namelen_r may contain garbage.
553 * Do not call _next again.
555 * There may also be errors, in which case *dmend_rlater,
556 * *namelen_rlater, *lablen_r and *labstart_r may contain garbage.
557 * Do not then call findlabel_next again.
564 adns_status adns__parse_domain(adns_state ads, int serv, adns_query qu,
565 vbuf *vb, parsedomain_flags flags,
566 const byte *dgram, int dglen, int *cbyte_io, int max);
567 /* vb must already have been initialised; it will be reset if necessary.
568 * If there is truncation, vb->used will be set to 0; otherwise
569 * (if there is no error) vb will be null-terminated.
570 * If there is an error vb and *cbyte_io may be left indeterminate.
572 * serv may be -1 and qu may be 0 - they are used for error reporting only.
575 adns_status adns__parse_domain_more(findlabel_state *fls, adns_state ads,
576 adns_query qu, vbuf *vb, parsedomain_flags flags,
578 /* Like adns__parse_domain, but you pass it a pre-initialised findlabel_state,
579 * for continuing an existing domain or some such of some kind. Also, unlike
580 * _parse_domain, the domain data will be appended to vb, rather than replacing
581 * the existing contents.
584 adns_status adns__findrr(adns_query qu, int serv,
585 const byte *dgram, int dglen, int *cbyte_io,
586 int *type_r, int *class_r, unsigned long *ttl_r,
587 int *rdlen_r, int *rdstart_r,
588 int *ownermatchedquery_r);
589 /* Finds the extent and some of the contents of an RR in a datagram
590 * and does some checks. The datagram is *dgram, length dglen, and
591 * the RR starts at *cbyte_io (which is updated afterwards to point
592 * to the end of the RR).
594 * The type, class, TTL and RRdata length and start are returned iff
595 * the corresponding pointer variables are not null. type_r, class_r
596 * and ttl_r may not be null. The TTL will be capped.
598 * If ownermatchedquery_r != 0 then the owner domain of this
599 * RR will be compared with that in the query (or, if the query
600 * has gone to a CNAME lookup, with the canonical name).
601 * In this case, *ownermatchedquery_r will be set to 0 or 1.
602 * The query datagram (or CNAME datagram) MUST be valid and not truncated.
604 * If there is truncation then *type_r will be set to -1 and
605 * *cbyte_io, *class_r, *rdlen_r, *rdstart_r and *eo_matched_r will be
608 * qu must obviously be non-null.
610 * If an error is returned then *type_r will be undefined too.
613 adns_status adns__findrr_anychk(adns_query qu, int serv,
614 const byte *dgram, int dglen, int *cbyte_io,
615 int *type_r, int *class_r, unsigned long *ttl_r,
616 int *rdlen_r, int *rdstart_r,
617 const byte *eo_dgram, int eo_dglen, int eo_cbyte,
619 /* Like adns__findrr_checked, except that the datagram and
620 * owner to compare with can be specified explicitly.
622 * If the caller thinks they know what the owner of the RR ought to
623 * be they can pass in details in eo_*: this is another (or perhaps
624 * the same datagram), and a pointer to where the putative owner
625 * starts in that datagram. In this case *eo_matched_r will be set
626 * to 1 if the datagram matched or 0 if it did not. Either
627 * both eo_dgram and eo_matched_r must both be non-null, or they
628 * must both be null (in which case eo_dglen and eo_cbyte will be ignored).
629 * The eo datagram and contained owner domain MUST be valid and
633 void adns__update_expires(adns_query qu, unsigned long ttl, struct timeval now);
634 /* Updates the `expires' field in the query, so that it doesn't exceed
638 int vbuf__append_quoted1035(vbuf *vb, const byte *buf, int len);
642 void adns__tcp_broken(adns_state ads, const char *what, const char *why);
643 /* what and why may be both 0, or both non-0. */
645 void adns__tcp_tryconnect(adns_state ads, struct timeval now);
647 void adns__autosys(adns_state ads, struct timeval now);
648 /* Make all the system calls we want to if the application wants us to.
649 * Must not be called from within adns internal processing functions,
650 * lest we end up in recursive descent !
653 void adns__must_gettimeofday(adns_state ads, const struct timeval **now_io,
654 struct timeval *tv_buf);
656 int adns__pollfds(adns_state ads, struct pollfd pollfds_buf[MAX_POLLFDS]);
657 void adns__fdevents(adns_state ads,
658 const struct pollfd *pollfds, int npollfds,
659 int maxfd, const fd_set *readfds,
660 const fd_set *writefds, const fd_set *exceptfds,
661 struct timeval now, int *r_r);
662 int adns__internal_check(adns_state ads,
663 adns_query *query_io,
664 adns_answer **answer,
667 void adns__timeouts(adns_state ads, int act,
668 struct timeval **tv_io, struct timeval *tvbuf,
670 /* If act is !0, then this will also deal with the TCP connection
671 * if previous events broke it or require it to be connected.
676 void adns__consistency(adns_state ads, adns_query qu, consistency_checks cc);
678 /* Useful static inline functions: */
680 static inline int ctype_whitespace(int c) { return c==' ' || c=='\n' || c=='\t'; }
681 static inline int ctype_digit(int c) { return c>='0' && c<='9'; }
682 static inline int ctype_alpha(int c) {
683 return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z');
685 static inline int ctype_822special(int c) { return strchr("()<>@,;:\\\".[]",c) != 0; }
686 static inline int ctype_domainunquoted(int c) {
687 return ctype_alpha(c) || ctype_digit(c) || (strchr("-_/+",c) != 0);
690 static inline int errno_resources(int e) { return e==ENOMEM || e==ENOBUFS; }
694 #define MEM_ROUND(sz) \
695 (( ((sz)+sizeof(union maxalign)-1) / sizeof(union maxalign) ) \
696 * sizeof(union maxalign) )
698 #define GETIL_B(cb) (((dgram)[(cb)++]) & 0x0ff)
699 #define GET_B(cb,tv) ((tv)= GETIL_B((cb)))
700 #define GET_W(cb,tv) ((tv)=0, (tv)|=(GETIL_B((cb))<<8), (tv)|=GETIL_B(cb), (tv))
701 #define GET_L(cb,tv) ( (tv)=0, \
702 (tv)|=(GETIL_B((cb))<<24), \
703 (tv)|=(GETIL_B((cb))<<16), \
704 (tv)|=(GETIL_B((cb))<<8), \