reactos/sdk/lib/3rdparty/adns/src/internal.h

   1 /*
   2  * internal.h
   3  * - declarations of private objects with external linkage (adns__*)
   4  * - definitons of internal macros
   5  * - comments regarding library data structures
   6  */
   7 /*
   8  *  This file is
   9  *    Copyright (C) 1997-2000 Ian Jackson <ian@davenant.greenend.org.uk>
  10  *
  11  *  It is part of adns, which is
  12  *    Copyright (C) 1997-2000 Ian Jackson <ian@davenant.greenend.org.uk>
  13  *    Copyright (C) 1999-2000 Tony Finch <dot@dotat.at>
  14  *
  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)
  18  *  any later version.
  19  *
  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.
  24  *
  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.
  28  */
  29
  30 #ifndef ADNS_INTERNAL_H_INCLUDED
  31 #define ADNS_INTERNAL_H_INCLUDED
  32
  33 #include "config.h"
  34
  35 #ifndef ADNS_JGAA_WIN32
  36 typedef unsigned char byte;
  37 #endif
  38
  39
  40 #include <stdarg.h>
  41 #include <assert.h>
  42
  43 #ifndef ADNS_JGAA_WIN32
  44 # include <unistd.h>
  45 #endif
  46 #include <signal.h>
  47 #include <errno.h>
  48 #include <string.h>
  49
  50 #ifndef ADNS_JGAA_WIN32
  51 #  include <sys/time.h>
  52 #endif
  53
  54 #include "adns.h"
  55 #include "dlist.h"
  56
  57 #ifdef ADNS_REGRESS_TEST
  58 # include "hredirect.h"
  59 #endif
  60
  61 /* Configuration and constants */
  62
  63 #define MAXSERVERS 5
  64 #define MAXSORTLIST 15
  65 #define UDPMAXRETRIES 15
  66 #define UDPRETRYMS 2000
  67 #define TCPWAITMS 30000
  68 #define TCPCONNMS 14000
  69 #define TCPIDLEMS 30000
  70 #define MAXTTLBELIEVE (7*86400) /* any TTL > 7 days is capped */
  71
  72 #define DNS_PORT 53
  73 #define DNS_MAXUDP 512
  74 #define DNS_MAXLABEL 63
  75 #define DNS_MAXDOMAIN 255
  76 #define DNS_HDRSIZE 12
  77 #define DNS_IDOFFSET 0
  78 #define DNS_CLASS_IN 1
  79
  80 #define DNS_INADDR_ARPA "in-addr", "arpa"
  81
  82 #define MAX_POLLFDS  ADNS_POLLFDS_RECOMMENDED
  83
  84 typedef enum {
  85   cc_user,
  86   cc_entex,
  87   cc_freq
  88 } consistency_checks;
  89
  90 typedef enum {
  91   rcode_noerror,
  92   rcode_formaterror,
  93   rcode_servfail,
  94   rcode_nxdomain,
  95   rcode_notimp,
  96   rcode_refused
  97 } dns_rcode;
  98
  99 /* Shared data structures */
 100
 101 typedef union {
 102   adns_status status;
 103   char *cp;
 104   adns_rrtype type;
 105   int i;
 106   struct in_addr ia;
 107   unsigned long ul;
 108 } rr_align;
 109
 110 typedef struct {
 111   int used, avail;
 112   byte *buf;
 113 } vbuf;
 114
 115 typedef struct {
 116   adns_state ads;
 117   adns_query qu;
 118   int serv;
 119   const byte *dgram;
 120   int dglen, nsstart, nscount, arcount;
 121   struct timeval now;
 122 } parseinfo;
 123
 124 typedef struct {
 125   adns_rrtype type;
 126   const char *rrtname;
 127   const char *fmtname;
 128   int rrsz;
 129
 130   void (*makefinal)(adns_query qu, void *data);
 131   /* Change memory management of *data.
 132    * Previously, used alloc_interim, now use alloc_final.
 133    */
 134
 135   adns_status (*convstring)(vbuf *vb, const void *data);
 136   /* Converts the RR data to a string representation in vbuf.
 137    * vbuf will be appended to (it must have been initialised),
 138    * and will not be null-terminated by convstring.
 139    */
 140
 141   adns_status (*parse)(const parseinfo *pai, int cbyte, int max, void *store_r);
 142   /* Parse one RR, in dgram of length dglen, starting at cbyte and
 143    * extending until at most max.
 144    *
 145    * The RR should be stored at *store_r, of length qu->typei->rrsz.
 146    *
 147    * If there is an overrun which might indicate truncation, it should set
 148    * *rdstart to -1; otherwise it may set it to anything else positive.
 149    *
 150    * nsstart is the offset of the authority section.
 151    */
 152
 153   int (*diff_needswap)(adns_state ads, const void *datap_a, const void *datap_b);
 154   /* Returns !0 if RR a should be strictly after RR b in the sort order,
 155    * 0 otherwise.  Must not fail.
 156    */
 157 } typeinfo;
 158
 159 typedef struct allocnode {
 160   struct allocnode *next, *back;
 161 } allocnode;
 162
 163 union maxalign {
 164   byte d[1];
 165   struct in_addr ia;
 166   long l;
 167   void *p;
 168   void (*fp)(void);
 169   union maxalign *up;
 170 };
 171
 172 typedef struct {
 173   void *ext;
 174   void (*callback)(adns_query parent, adns_query child);
 175   union {
 176     adns_rr_addr ptr_parent_addr;
 177     adns_rr_hostaddr *hostaddr;
 178   } info;
 179 } qcontext;
 180
 181 struct adns__query {
 182   adns_state ads;
 183   enum { query_tosend, query_tcpw, query_childw, query_done } state;
 184   adns_query back, next, parent;
 185   struct { adns_query head, tail; } children;
 186   struct { adns_query back, next; } siblings;
 187   struct { allocnode *head, *tail; } allocations;
 188   int interim_allocd, preserved_allocd;
 189   void *final_allocspace;
 190
 191   const typeinfo *typei;
 192   byte *query_dgram;
 193   int query_dglen;
 194
 195   vbuf vb;
 196   /* General-purpose messing-about buffer.
 197    * Wherever a `big' interface is crossed, this may be corrupted/changed
 198    * unless otherwise specified.
 199    */
 200
 201   adns_answer *answer;
 202   /* This is allocated when a query is submitted, to avoid being unable
 203    * to relate errors to queries if we run out of memory.  During
 204    * query processing status, rrs is 0.  cname is set if
 205    * we found a cname (this corresponds to cname_dgram in the query
 206    * structure).  type is set from the word go.  nrrs and rrs
 207    * are set together, when we find how many rrs there are.
 208    * owner is set during querying unless we're doing searchlist,
 209    * in which case it is set only when we find an answer.
 210    */
 211
 212   byte *cname_dgram;
 213   int cname_dglen, cname_begin;
 214   /* If non-0, has been allocated using . */
 215
 216   vbuf search_vb;
 217   int search_origlen, search_pos, search_doneabs;
 218   /* Used by the searching algorithm.  The query domain in textual form
 219    * is copied into the vbuf, and _origlen set to its length.  Then
 220    * we walk the searchlist, if we want to.  _pos says where we are
 221    * (next entry to try), and _doneabs says whether we've done the
 222    * absolute query yet (0=not yet, 1=done, -1=must do straight away,
 223    * but not done yet).  If flags doesn't have adns_qf_search then
 224    * the vbuf is initialised but empty and everything else is zero.
 225    */
 226
 227   int id, flags, retries;
 228   int udpnextserver;
 229   unsigned long udpsent; /* bitmap indexed by server */
 230   struct timeval timeout;
 231   time_t expires; /* Earliest expiry time of any record we used. */
 232
 233   qcontext ctx;
 234
 235   /* Possible states:
 236    *
 237    *  state   Queue   child  id   nextudpserver  udpsent     tcpfailed
 238    *
 239    *  tosend  NONE    null   >=0  0              zero        zero
 240    *  tosend  udpw    null   >=0  any            nonzero     zero
 241    *  tosend  NONE    null   >=0  any            nonzero     zero
 242    *
 243    *  tcpw    tcpw    null   >=0  irrelevant     any         any
 244    *
 245    *  child   childw  set    >=0  irrelevant     irrelevant  irrelevant
 246    *  child   NONE    null   >=0  irrelevant     irrelevant  irrelevant
 247    *  done    output  null   -1   irrelevant     irrelevant  irrelevant
 248    *
 249    * Queries are only not on a queue when they are actually being processed.
 250    * Queries in state tcpw/tcpw have been sent (or are in the to-send buffer)
 251    * iff the tcp connection is in state server_ok.
 252    *
 253    *                          +------------------------+
 254    *             START -----> |      tosend/NONE       |
 255    *                          +------------------------+
 256    *                         /                       |\  \
 257    *        too big for UDP /             UDP timeout  \  \ send via UDP
 258    *        send via TCP   /              more retries  \  \
 259    *        when conn'd   /                  desired     \  \
 260    *                     |                                |  |
 261    *                     v                                |  v
 262    *              +-----------+                         +-------------+
 263    *              | tcpw/tcpw | ________                | tosend/udpw |
 264    *              +-----------+         \               +-------------+
 265    *                 |    |              |     UDP timeout | |
 266    *                 |    |              |      no more    | |
 267    *                 |    |              |      retries    | |
 268    *                  \   | TCP died     |      desired    | |
 269    *                   \   \ no more     |                 | |
 270    *                    \   \ servers    | TCP            /  |
 271    *                     \   \ to try    | timeout       /   |
 272    *                  got \   \          v             |_    | got
 273    *                 reply \   _| +------------------+      / reply
 274    *                        \     | done/output FAIL |     /
 275    *                         \    +------------------+    /
 276    *                          \                          /
 277    *                           _|                      |_
 278    *                             (..... got reply ....)
 279    *                              /                   \
 280    *        need child query/ies /                     \ no child query
 281    *                            /                       \
 282    *                          |_                         _|
 283    *               +---------------+                   +----------------+
 284    *               | childw/childw | ----------------> | done/output OK |
 285    *               +---------------+  children done    +----------------+
 286    */
 287 };
 288
 289 struct query_queue { adns_query head, tail; };
 290
 291 struct adns__state {
 292   adns_initflags iflags;
 293   FILE *diagfile;
 294   int configerrno;
 295   struct query_queue udpw, tcpw, childw, output;
 296   adns_query forallnext;
 297   int nextid;
 298   ADNS_SOCKET udpsocket, tcpsocket;
 299   vbuf tcpsend, tcprecv;
 300   int nservers, nsortlist, nsearchlist, searchndots, tcpserver, tcprecv_skip;
 301   enum adns__tcpstate {
 302     server_disconnected, server_connecting,
 303     server_ok, server_broken
 304   } tcpstate;
 305   struct timeval tcptimeout;
 306   /* This will have tv_sec==0 if it is not valid.  It will always be
 307    * valid if tcpstate _connecting.  When _ok, it will be nonzero if
 308    * we are idle (ie, tcpw queue is empty), in which case it is the
 309    * absolute time when we will close the connection.
 310    */
 311 #ifndef ADNS_JGAA_WIN32
 312   struct sigaction stdsigpipe;
 313   sigset_t stdsigmask;
 314 #endif
 315   struct pollfd pollfds_buf[MAX_POLLFDS];
 316   struct server {
 317     struct in_addr addr;
 318   } servers[MAXSERVERS];
 319   struct sortlist {
 320     struct in_addr base, mask;
 321   } sortlist[MAXSORTLIST];
 322   char **searchlist;
 323 };
 324
 325 /* From setup.c: */
 326
 327 int adns__setnonblock(adns_state ads, ADNS_SOCKET fd); /* => errno value */
 328
 329 /* From general.c: */
 330
 331 void adns__vdiag(adns_state ads, const char *pfx, adns_initflags prevent,
 332                  int serv, adns_query qu, const char *fmt, va_list al);
 333
 334 void adns__debug(adns_state ads, int serv, adns_query qu,
 335                  const char *fmt, ...) PRINTFFORMAT(4,5);
 336 void adns__warn(adns_state ads, int serv, adns_query qu,
 337                 const char *fmt, ...) PRINTFFORMAT(4,5);
 338 void adns__diag(adns_state ads, int serv, adns_query qu,
 339                 const char *fmt, ...) PRINTFFORMAT(4,5);
 340
 341 int adns__vbuf_ensure(vbuf *vb, int want);
 342 int adns__vbuf_appendstr(vbuf *vb, const char *data); /* does not include nul */
 343 int adns__vbuf_append(vbuf *vb, const byte *data, int len);
 344 /* 1=>success, 0=>realloc failed */
 345 void adns__vbuf_appendq(vbuf *vb, const byte *data, int len);
 346 void adns__vbuf_init(vbuf *vb);
 347 void adns__vbuf_free(vbuf *vb);
 348
 349 const char *adns__diag_domain(adns_state ads, int serv, adns_query qu,
 350                               vbuf *vb, const byte *dgram, int dglen, int cbyte);
 351 /* Unpicks a domain in a datagram and returns a string suitable for
 352  * printing it as.  Never fails - if an error occurs, it will
 353  * return some kind of string describing the error.
 354  *
 355  * serv may be -1 and qu may be 0.  vb must have been initialised,
 356  * and will be left in an arbitrary consistent state.
 357  *
 358  * Returns either vb->buf, or a pointer to a string literal.  Do not modify
 359  * vb before using the return value.
 360  */
 361
 362 void adns__isort(void *array, int nobjs, int sz, void *tempbuf,
 363                  int (*needswap)(void *context, const void *a, const void *b),
 364                  void *context);
 365 /* Does an insertion sort of array which must contain nobjs objects
 366  * each sz bytes long.  tempbuf must point to a buffer at least
 367  * sz bytes long.  needswap should return !0 if a>b (strictly, ie
 368  * wrong order) 0 if a<=b (ie, order is fine).
 369  */
 370
 371 void adns__sigpipe_protect(adns_state);
 372 void adns__sigpipe_unprotect(adns_state);
 373 /* If SIGPIPE protection is not disabled, will block all signals except
 374  * SIGPIPE, and set SIGPIPE's disposition to SIG_IGN.  (And then restore.)
 375  * Each call to _protect must be followed by a call to _unprotect before
 376  * any significant amount of code gets to run, since the old signal mask
 377  * is stored in the adns structure.
 378  */
 379
 380 /* From transmit.c: */
 381
 382 adns_status adns__mkquery(adns_state ads, vbuf *vb, int *id_r,
 383                           const char *owner, int ol,
 384                           const typeinfo *typei, adns_queryflags flags);
 385 /* Assembles a query packet in vb.  A new id is allocated and returned.
 386  */
 387
 388 adns_status adns__mkquery_frdgram(adns_state ads, vbuf *vb, int *id_r,
 389                                   const byte *qd_dgram, int qd_dglen, int qd_begin,
 390                                   adns_rrtype type, adns_queryflags flags);
 391 /* Same as adns__mkquery, but takes the owner domain from an existing datagram.
 392  * That domain must be correct and untruncated.
 393  */
 394
 395 void adns__querysend_tcp(adns_query qu, struct timeval now);
 396 /* Query must be in state tcpw/tcpw; it will be sent if possible and
 397  * no further processing can be done on it for now.  The connection
 398  * might be broken, but no reconnect will be attempted.
 399  */
 400
 401 void adns__query_send(adns_query qu, struct timeval now);
 402 /* Query must be in state tosend/NONE; it will be moved to a new state,
 403  * and no further processing can be done on it for now.
 404  * (Resulting state is one of udp/timew, tcpwait/timew (if server not connected),
 405  *  tcpsent/timew, child/childw or done/output.)
 406  * __query_send may decide to use either UDP or TCP depending whether
 407  * _qf_usevc is set (or has become set) and whether the query is too
 408  * large.
 409  */
 410
 411 /* From query.c: */
 412
 413 adns_status adns__internal_submit(adns_state ads, adns_query *query_r,
 414                                   const typeinfo *typei, vbuf *qumsg_vb, int id,
 415                                   adns_queryflags flags, struct timeval now,
 416                                   const qcontext *ctx);
 417 /* Submits a query (for internal use, called during external submits).
 418  *
 419  * The new query is returned in *query_r, or we return adns_s_nomemory.
 420  *
 421  * The query datagram should already have been assembled in qumsg_vb;
 422  * the memory for it is _taken over_ by this routine whether it
 423  * succeeds or fails (if it succeeds, the vbuf is reused for qu->vb).
 424  *
 425  * *ctx is copied byte-for-byte into the query.
 426  *
 427  * When the child query is done, ctx->callback will be called.  The
 428  * child will already have been taken off both the global list of
 429  * queries in ads and the list of children in the parent.  The child
 430  * will be freed when the callback returns.  The parent will have been
 431  * taken off the global childw queue.
 432  *
 433  * The callback should either call adns__query_done, if it is
 434  * complete, or adns__query_fail, if an error has occurred, in which
 435  * case the other children (if any) will be cancelled.  If the parent
 436  * has more unfinished children (or has just submitted more) then the
 437  * callback may choose to wait for them - it must then put the parent
 438  * back on the childw queue.
 439  */
 440
 441 void adns__search_next(adns_state ads, adns_query qu, struct timeval now);
 442 /* Walks down the searchlist for a query with adns_qf_search.
 443  * The query should have just had a negative response, or not had
 444  * any queries sent yet, and should not be on any queue.
 445  * The query_dgram if any will be freed and forgotten and a new
 446  * one constructed from the search_* members of the query.
 447  *
 448  * Cannot fail (in case of error, calls adns__query_fail).
 449  */
 450
 451 void *adns__alloc_interim(adns_query qu, size_t sz);
 452 void *adns__alloc_preserved(adns_query qu, size_t sz);
 453 /* Allocates some memory, and records which query it came from
 454  * and how much there was.
 455  *
 456  * If an error occurs in the query, all the memory from _interim is
 457  * simply freed.  If the query succeeds, one large buffer will be made
 458  * which is big enough for all these allocations, and then
 459  * adns__alloc_final will get memory from this buffer.
 460  *
 461  * _alloc_interim can fail (and return 0).
 462  * The caller must ensure that the query is failed.
 463  *
 464  * The memory from _preserved is is kept and transferred into the
 465  * larger buffer - unless we run out of memory, in which case it too
 466  * is freed.  When you use _preserved you have to add code to the
 467  * x_nomem error exit case in adns__makefinal_query to clear out the
 468  * pointers you made to those allocations, because that's when they're
 469  * thrown away; you should also make a note in the declaration of
 470  * those pointer variables, to note that they are _preserved rather
 471  * than _interim.  If they're in the answer, note it here:
 472  *  answer->cname and answer->owner are _preserved.
 473  */
 474
 475 void adns__transfer_interim(adns_query from, adns_query to, void *block, size_t sz);
 476 /* Transfers an interim allocation from one query to another, so that
 477  * the `to' query will have room for the data when we get to makefinal
 478  * and so that the free will happen when the `to' query is freed
 479  * rather than the `from' query.
 480  *
 481  * It is legal to call adns__transfer_interim with a null pointer; this
 482  * has no effect.
 483  *
 484  * _transfer_interim also ensures that the expiry time of the `to' query
 485  * is no later than that of the `from' query, so that child queries'
 486  * TTLs get inherited by their parents.
 487  */
 488
 489 void *adns__alloc_mine(adns_query qu, size_t sz);
 490 /* Like _interim, but does not record the length for later
 491  * copying into the answer.  This just ensures that the memory
 492  * will be freed when we're done with the query.
 493  */
 494
 495 void *adns__alloc_final(adns_query qu, size_t sz);
 496 /* Cannot fail, and cannot return 0.
 497  */
 498
 499 void adns__makefinal_block(adns_query qu, void **blpp, size_t sz);
 500 void adns__makefinal_str(adns_query qu, char **strp);
 501
 502 void adns__reset_preserved(adns_query qu);
 503 /* Resets all of the memory management stuff etc. to take account of
 504  * only the _preserved stuff from _alloc_preserved.  Used when we find
 505  * an error somewhere and want to just report the error (with perhaps
 506  * CNAME, owner, etc. info), and also when we're halfway through RRs
 507  * in a datagram and discover that we need to retry the query.
 508  */
 509
 510 void adns__query_done(adns_query qu);
 511 void adns__query_fail(adns_query qu, adns_status stat);
 512
 513 /* From reply.c: */
 514
 515 void adns__procdgram(adns_state ads, const byte *dgram, int len,
 516                      int serv, int viatcp, struct timeval now);
 517 /* This function is allowed to cause new datagrams to be constructed
 518  * and sent, or even new queries to be started.  However,
 519  * query-sending functions are not allowed to call any general event
 520  * loop functions in case they accidentally call this.
 521  *
 522  * Ie, receiving functions may call sending functions.
 523  * Sending functions may NOT call receiving functions.
 524  */
 525
 526 /* From types.c: */
 527
 528 const typeinfo *adns__findtype(adns_rrtype type);
 529
 530 /* From parse.c: */
 531
 532 typedef struct {
 533   adns_state ads;
 534   adns_query qu;
 535   int serv;
 536   const byte *dgram;
 537   int dglen, max, cbyte, namelen;
 538   int *dmend_r;
 539 } findlabel_state;
 540
 541 void adns__findlabel_start(findlabel_state *fls, adns_state ads,
 542                            int serv, adns_query qu,
 543                            const byte *dgram, int dglen, int max,
 544                            int dmbegin, int *dmend_rlater);
 545 /* Finds labels in a domain in a datagram.
 546  *
 547  * Call this routine first.
 548  * dmend_rlater may be null.  ads (and of course fls) may not be.
 549  * serv may be -1, qu may be null - they are for error reporting.
 550  */
 551
 552 adns_status adns__findlabel_next(findlabel_state *fls, int *lablen_r, int *labstart_r);
 553 /* Then, call this one repeatedly.
 554  *
 555  * It will return adns_s_ok if all is well, and tell you the length
 556  * and start of successive labels.  labstart_r may be null, but
 557  * lablen_r must not be.
 558  *
 559  * After the last label, it will return with *lablen_r zero.
 560  * Do not then call it again; instead, just throw away the findlabel_state.
 561  *
 562  * *dmend_rlater will have been set to point to the next part of
 563  * the datagram after the label (or after the uncompressed part,
 564  * if compression was used).  *namelen_rlater will have been set
 565  * to the length of the domain name (total length of labels plus
 566  * 1 for each intervening dot).
 567  *
 568  * If the datagram appears to be truncated, *lablen_r will be -1.
 569  * *dmend_rlater, *labstart_r and *namelen_r may contain garbage.
 570  * Do not call _next again.
 571  *
 572  * There may also be errors, in which case *dmend_rlater,
 573  * *namelen_rlater, *lablen_r and *labstart_r may contain garbage.
 574  * Do not then call findlabel_next again.
 575  */
 576
 577 typedef enum {
 578   pdf_quoteok= 0x001
 579 } parsedomain_flags;
 580
 581 adns_status adns__parse_domain(adns_state ads, int serv, adns_query qu,
 582                                vbuf *vb, adns_queryflags flags,
 583                                const byte *dgram, int dglen, int *cbyte_io, int max);
 584 /* vb must already have been initialised; it will be reset if necessary.
 585  * If there is truncation, vb->used will be set to 0; otherwise
 586  * (if there is no error) vb will be null-terminated.
 587  * If there is an error vb and *cbyte_io may be left indeterminate.
 588  *
 589  * serv may be -1 and qu may be 0 - they are used for error reporting only.
 590  */
 591
 592 adns_status adns__parse_domain_more(findlabel_state *fls, adns_state ads,
 593                                     adns_query qu, vbuf *vb, parsedomain_flags flags,
 594                                     const byte *dgram);
 595 /* Like adns__parse_domain, but you pass it a pre-initialised findlabel_state,
 596  * for continuing an existing domain or some such of some kind.  Also, unlike
 597  * _parse_domain, the domain data will be appended to vb, rather than replacing
 598  * the existing contents.
 599  */
 600
 601 adns_status adns__findrr(adns_query qu, int serv,
 602                          const byte *dgram, int dglen, int *cbyte_io,
 603                          int *type_r, int *class_r, unsigned long *ttl_r,
 604                          int *rdlen_r, int *rdstart_r,
 605                          int *ownermatchedquery_r);
 606 /* Finds the extent and some of the contents of an RR in a datagram
 607  * and does some checks.  The datagram is *dgram, length dglen, and
 608  * the RR starts at *cbyte_io (which is updated afterwards to point
 609  * to the end of the RR).
 610  *
 611  * The type, class, TTL and RRdata length and start are returned iff
 612  * the corresponding pointer variables are not null.  type_r, class_r
 613  * and ttl_r may not be null.  The TTL will be capped.
 614  *
 615  * If ownermatchedquery_r != 0 then the owner domain of this
 616  * RR will be compared with that in the query (or, if the query
 617  * has gone to a CNAME lookup, with the canonical name).
 618  * In this case, *ownermatchedquery_r will be set to 0 or 1.
 619  * The query datagram (or CNAME datagram) MUST be valid and not truncated.
 620  *
 621  * If there is truncation then *type_r will be set to -1 and
 622  * *cbyte_io, *class_r, *rdlen_r, *rdstart_r and *eo_matched_r will be
 623  * undefined.
 624  *
 625  * qu must obviously be non-null.
 626  *
 627  * If an error is returned then *type_r will be undefined too.
 628  */
 629
 630 adns_status adns__findrr_anychk(adns_query qu, int serv,
 631                                 const byte *dgram, int dglen, int *cbyte_io,
 632                                 int *type_r, int *class_r, unsigned long *ttl_r,
 633                                 int *rdlen_r, int *rdstart_r,
 634                                 const byte *eo_dgram, int eo_dglen, int eo_cbyte,
 635                                 int *eo_matched_r);
 636 /* Like adns__findrr_checked, except that the datagram and
 637  * owner to compare with can be specified explicitly.
 638  *
 639  * If the caller thinks they know what the owner of the RR ought to
 640  * be they can pass in details in eo_*: this is another (or perhaps
 641  * the same datagram), and a pointer to where the putative owner
 642  * starts in that datagram.  In this case *eo_matched_r will be set
 643  * to 1 if the datagram matched or 0 if it did not.  Either
 644  * both eo_dgram and eo_matched_r must both be non-null, or they
 645  * must both be null (in which case eo_dglen and eo_cbyte will be ignored).
 646  * The eo datagram and contained owner domain MUST be valid and
 647  * untruncated.
 648  */
 649
 650 void adns__update_expires(adns_query qu, unsigned long ttl, struct timeval now);
 651 /* Updates the `expires' field in the query, so that it doesn't exceed
 652  * now + ttl.
 653  */
 654
 655 int vbuf__append_quoted1035(vbuf *vb, const byte *buf, int len);
 656
 657 /* From event.c: */
 658
 659 void adns__tcp_broken(adns_state ads, const char *what, const char *why);
 660 /* what and why may be both 0, or both non-0. */
 661
 662 void adns__tcp_tryconnect(adns_state ads, struct timeval now);
 663
 664 void adns__autosys(adns_state ads, struct timeval now);
 665 /* Make all the system calls we want to if the application wants us to.
 666  * Must not be called from within adns internal processing functions,
 667  * lest we end up in recursive descent !
 668  */
 669
 670 void adns__must_gettimeofday(adns_state ads, const struct timeval **now_io,
 671                              struct timeval *tv_buf);
 672
 673 int adns__pollfds(adns_state ads, struct pollfd pollfds_buf[MAX_POLLFDS]);
 674 void adns__fdevents(adns_state ads,
 675                     const struct pollfd *pollfds, int npollfds,
 676                     int maxfd, const fd_set *readfds,
 677                     const fd_set *writefds, const fd_set *exceptfds,
 678                     struct timeval now, int *r_r);
 679 int adns__internal_check(adns_state ads,
 680                          adns_query *query_io,
 681                          adns_answer **answer,
 682                          void **context_r);
 683
 684 void adns__timeouts(adns_state ads, int act,
 685                     struct timeval **tv_io, struct timeval *tvbuf,
 686                     struct timeval now);
 687 /* If act is !0, then this will also deal with the TCP connection
 688  * if previous events broke it or require it to be connected.
 689  */
 690
 691 /* From check.c: */
 692
 693 void adns__consistency(adns_state ads, adns_query qu, consistency_checks cc);
 694
 695 /* Useful static inline functions: */
 696
 697 static inline int ctype_whitespace(int c) { return c==' ' || c=='\n' || c=='\t'; }
 698 static inline int ctype_digit(int c) { return c>='0' && c<='9'; }
 699 static inline int ctype_alpha(int c) {
 700   return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z');
 701 }
 702 static inline int ctype_822special(int c) { return strchr("()<>@,;:\\\".[]",c) != 0; }
 703 static inline int ctype_domainunquoted(int c) {
 704   return ctype_alpha(c) || ctype_digit(c) || (strchr("-_/+",c) != 0);
 705 }
 706
 707 static inline int errno_resources(int e) { return e==ENOMEM || e==ENOBUFS; }
 708
 709 /* Useful macros */
 710
 711 #define MEM_ROUND(sz) \
 712   (( ((sz)+sizeof(union maxalign)-1) / sizeof(union maxalign) ) \
 713    * sizeof(union maxalign) )
 714
 715 #define GETIL_B(cb) (((dgram)[(cb)++]) & 0x0ff)
 716 #define GET_B(cb,tv) ((tv)= GETIL_B((cb)))
 717 #define GET_W(cb,tv) ((tv)=0, (tv)|=(GETIL_B((cb))<<8), (tv)|=GETIL_B(cb), (tv))
 718 #define GET_L(cb,tv) ( (tv)=0, \
 719                        (tv)|=(GETIL_B((cb))<<24), \
 720                        (tv)|=(GETIL_B((cb))<<16), \
 721                        (tv)|=(GETIL_B((cb))<<8), \
 722                        (tv)|=GETIL_B(cb), \
 723                        (tv) )
 724
 725 #endif