mdw@git.distorted.org.uk Git - adns/blob - 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 part of adns, which is Copyright (C) 1997, 1998 Ian Jackson
   9  *
  10  *  This program is free software; you can redistribute it and/or modify
  11  *  it under the terms of the GNU General Public License as published by
  12  *  the Free Software Foundation; either version 2, or (at your option)
  13  *  any later version.
  14  *
  15  *  This program is distributed in the hope that it will be useful,
  16  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  *  GNU General Public License for more details.
  19  *
  20  *  You should have received a copy of the GNU General Public License
  21  *  along with this program; if not, write to the Free Software Foundation,
  22  *  Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  23  */
  24
  25 #ifndef ADNS_INTERNAL_H_INCLUDED
  26 #define ADNS_INTERNAL_H_INCLUDED
  27
  28 #define PRINTFFORMAT(a,b) __attribute__((format(printf,a,b)))
  29 typedef unsigned char byte;
  30
  31 #include <stdarg.h>
  32 #include <assert.h>
  33 #include <unistd.h>
  34
  35 #include <sys/time.h>
  36
  37 #include "adns.h"
  38
  39 /* Configuration and constants */
  40
  41 #define MAXSERVERS 5
  42 #define UDPMAXRETRIES /*15*/5
  43 #define UDPRETRYMS 2000
  44 #define TCPMS 30000
  45 #define LOCALRESOURCEMS 20
  46
  47 #define DNS_PORT 53
  48 #define DNS_MAXUDP 512
  49 #define DNS_MAXDOMAIN 255
  50 #define DNS_HDRSIZE 12
  51 #define DNS_CLASS_IN 1
  52
  53 typedef enum {
  54   rcode_noerror,
  55   rcode_formaterror,
  56   rcode_servfail,
  57   rcode_nxdomain,
  58   rcode_notimp,
  59   rcode_refused
  60 } dns_rcode;
  61
  62 /* Shared data structures */
  63
  64 typedef union {
  65   adns_status status;
  66   char *cp;
  67   adns_rrtype type;
  68   int i;
  69   struct in_addr ia;
  70   unsigned long ul;
  71 } rr_align;
  72
  73 typedef struct {
  74   int used, avail;
  75   byte *buf;
  76 } vbuf;
  77
  78 typedef union {
  79   void *ext;
  80   int dmaddr_index;
  81 } qcontext;
  82
  83 typedef struct {
  84   adns_rrtype type;
  85   const char *rrtname;
  86   const char *fmtname;
  87   int rrsz;
  88
  89   void (*makefinal)(adns_query qu, void *data);
  90   /* Change memory management of *data.
  91    * Previously, used alloc_interim, now use alloc_final.
  92    */
  93
  94   adns_status (*convstring)(vbuf *vb, const void *data);
  95   /* Converts the RR data to a string representation in vbuf.
  96    * vbuf will be appended to (it must have been initialised),
  97    * and will not be null-terminated by convstring.
  98    */
  99
 100   adns_status (*parse)(adns_query qu, int serv,
 101                        const byte *dgram, int dglen, int cbyte, int max,
 102                        void *store_r);
 103   /* Parse one RR, in dgram of length dglen, starting at cbyte and
 104    * extending until at most max.
 105    *
 106    * The RR should be stored at *store_r, of length qu->typei->rrsz.
 107    *
 108    * If there is an overrun which might indicate truncation, it should set
 109    * *rdstart to -1; otherwise it may set it to anything else positive.
 110    */
 111
 112   int (*diff_needswap)(const void *datap_a, const void *datap_b);
 113   /* Returns >0 if RR a should be strictly after RR b in the sort order,
 114    * 0 otherwise.  Must not fail.
 115    */
 116 } typeinfo;
 117
 118 typedef struct allocnode {
 119   struct allocnode *next;
 120 } allocnode;
 121
 122 union maxalign {
 123   byte d[1];
 124   struct in_addr ia;
 125   long l;
 126   void *p;
 127   void (*fp)(void);
 128   union maxalign *up;
 129 } data;
 130
 131 struct adns__query {
 132   adns_state ads;
 133   enum { query_udp, query_tcpwait, query_tcpsent, query_child, query_done } state;
 134   adns_query back, next, parent;
 135   struct { adns_query head, tail; } children;
 136   struct { adns_query back, next; } siblings;
 137   struct allocnode *allocations;
 138   int interim_allocd;
 139   void *final_allocspace;
 140
 141   const typeinfo *typei;
 142   byte *query_dgram;
 143   int query_dglen;
 144
 145   vbuf vb;
 146   /* General-purpose messing-about buffer.
 147    * Wherever a `big' interface is crossed, this may be corrupted/changed
 148    * unless otherwise specified.
 149    */
 150
 151   adns_answer *answer;
 152   /* This is allocated when a query is submitted, to avoid being unable
 153    * to relate errors to queries if we run out of memory.  During
 154    * query processing status, rrs is 0.  cname is set if
 155    * we found a cname (this corresponds to cname_dgram in the query
 156    * structure).  type is set from the word go.  nrrs and rrs
 157    * are set together, when we find how many rrs there are.
 158    */
 159
 160   byte *cname_dgram;
 161   int cname_dglen, cname_begin;
 162   /* If non-0, has been allocated using . */
 163
 164   int id, flags, udpretries;
 165   int udpnextserver;
 166   unsigned long udpsent, tcpfailed; /* bitmap indexed by server */
 167   struct timeval timeout;
 168   qcontext context;
 169
 170   /* Possible states:
 171    *
 172    *  state   Queue   child  id   nextudpserver  sentudp     failedtcp
 173    *
 174    *  udp     NONE    null   >=0  0              zero        zero
 175    *  udp     timew   null   >=0  any            nonzero     zero
 176    *  udp     NONE    null   >=0  any            nonzero     zero
 177    *
 178    *  tcpwait timew   null   >=0  irrelevant     zero        any
 179    *  tcpsent timew   null   >=0  irrelevant     zero        any
 180    *
 181    *  child   childw  set    >=0  irrelevant     irrelevant  irrelevant
 182    *  done    output  null   -1   irrelevant     irrelevant  irrelevant
 183    *
 184    *                          +------------------------+
 185    *             START -----> |      udp/NONE          |
 186    *                          +------------------------+
 187    *                         /                       |\  \
 188    *        too big for UDP /             UDP timeout  \  \ send via UDP
 189    *        do this ASAP!  /              more retries  \  \   do this ASAP!
 190    *                     |_                  desired     \  _|
 191    *              +---------------+                     +-----------+
 192    *              | tcpwait/timew | ____                | udp/timew |
 193    *              +---------------+     \               +-----------+
 194    *                    |  ^             |                 | |
 195    *     TCP conn'd;    |  | TCP died    |                 | |
 196    *     send via TCP   |  | more        |     UDP timeout | |
 197    *     do this ASAP!  |  | servers     |      no more    | |
 198    *                    v  | to try      |      retries    | |
 199    *              +---------------+      |      desired    | |
 200    *              | tcpsent/timew | ____ |                 | |
 201    *              +---------------+     \|                 | |
 202    *                  \   \ TCP died     | TCP             | |
 203    *                   \   \ no more     | timeout         / |
 204    *                    \   \ servers    |                /  |
 205    *                     \   \ to try    |               /   |
 206    *                  got \   \          v             |_    / got
 207    *                 reply \   _| +------------------+      / reply
 208    *                        \     | done/output FAIL |     /
 209    *                         \    +------------------+    /
 210    *                          \                          /
 211    *                           _|                      |_
 212    *                             (..... got reply ....)
 213    *                              /                   \
 214    *        need child query/ies /                     \ no child query
 215    *                            /                       \
 216    *                          |_                         _|
 217    *                +--------------+                   +----------------+
 218    *                | child/childw | ----------------> | done/output OK |
 219    *                +--------------+  children done    +----------------+
 220    */
 221 };
 222
 223 struct adns__state {
 224   adns_initflags iflags;
 225   FILE *diagfile;
 226   struct { adns_query head, tail; } timew, childw, output;
 227   int nextid, udpsocket, tcpsocket;
 228   vbuf tcpsend, tcprecv;
 229   int nservers, tcpserver;
 230   enum adns__tcpstate { server_disconnected, server_connecting, server_ok } tcpstate;
 231   struct timeval tcptimeout;
 232   struct server {
 233     struct in_addr addr;
 234   } servers[MAXSERVERS];
 235 };
 236
 237 /* From setup.c: */
 238
 239 int adns__setnonblock(adns_state ads, int fd); /* => errno value */
 240
 241 /* From general.c: */
 242
 243 void adns__vdiag(adns_state ads, const char *pfx, adns_initflags prevent,
 244                  int serv, adns_query qu, const char *fmt, va_list al);
 245
 246 void adns__debug(adns_state ads, int serv, adns_query qu,
 247                  const char *fmt, ...) PRINTFFORMAT(4,5);
 248 void adns__warn(adns_state ads, int serv, adns_query qu,
 249                 const char *fmt, ...) PRINTFFORMAT(4,5);
 250 void adns__diag(adns_state ads, int serv, adns_query qu,
 251                 const char *fmt, ...) PRINTFFORMAT(4,5);
 252
 253 int adns__vbuf_ensure(vbuf *vb, int want);
 254 int adns__vbuf_appendstr(vbuf *vb, const char *data); /* does not include nul */
 255 int adns__vbuf_append(vbuf *vb, const byte *data, int len);
 256 /* 1=>success, 0=>realloc failed */
 257 void adns__vbuf_appendq(vbuf *vb, const byte *data, int len);
 258 void adns__vbuf_init(vbuf *vb);
 259 void adns__vbuf_free(vbuf *vb);
 260
 261 const char *adns__diag_domain(adns_state ads, int serv, adns_query qu, vbuf *vb,
 262                               int flags, const byte *dgram, int dglen, int cbyte);
 263 /* Unpicks a domain in a datagram and returns a string suitable for
 264  * printing it as.  Never fails - if an error occurs, it will
 265  * return some kind of string describing the error.
 266  *
 267  * serv may be -1 and qu may be 0.  vb must have been initialised,
 268  * and will be left in an arbitrary consistent state.
 269  *
 270  * Returns either vb->buf, or a pointer to a string literal.  Do not modify
 271  * vb before using the return value.
 272  */
 273
 274 /* From transmit.c: */
 275
 276 adns_status adns__mkquery(adns_state ads, vbuf *vb, int *id_r,
 277                           const char *owner, int ol,
 278                           const typeinfo *typei, adns_queryflags flags);
 279 /* Assembles a query packet in vb, and returns id at *id_r. */
 280
 281 adns_status adns__mkquery_frdgram(adns_state ads, vbuf *vb, int *id_r,
 282                                   const byte *qd_dgram, int qd_dglen, int qd_begin,
 283                                   adns_rrtype type, adns_queryflags flags);
 284 /* Same as adns__mkquery, but takes the owner domain from an existing datagram.
 285  * That domain must be correct and untruncated.
 286  */
 287
 288 void adns__query_tcp(adns_query qu, struct timeval now);
 289 /* Query must be in state tcpwait/timew; it will be moved to a new state
 290  * if possible and no further processing can be done on it for now.
 291  * (Resulting state is one of tcpwait/timew (if server not connected),
 292  *  tcpsent/timew, child/childw or done/output.)
 293  *
 294  * adns__tcp_tryconnect should already have been called - _tcp
 295  * will only use an existing connection (if there is one), which it
 296  * may break.  If the conn list lost then the caller is responsible for any
 297  * reestablishment and retry.
 298  */
 299
 300 void adns__query_udp(adns_query qu, struct timeval now);
 301 /* Query must be in state udp/NONE; it will be moved to a new state,
 302  * and no further processing can be done on it for now.
 303  * (Resulting state is one of udp/timew, tcpwait/timew (if server not connected),
 304  *  tcpsent/timew, child/childw or done/output.)
 305  */
 306
 307 /* From query.c: */
 308
 309 int adns__internal_submit(adns_state ads, adns_query *query_r,
 310                           const typeinfo *typei, vbuf *qumsg_vb, int id,
 311                           adns_queryflags flags, struct timeval now,
 312                           adns_status failstat, const qcontext *ctx);
 313 /* Submits a query (for internal use, called during external submits).
 314  *
 315  * The new query is returned in *query_r, or we return adns_s_nomemory.
 316  *
 317  * The query datagram should already have been assembled in qumsg_vb;
 318  * the memory for it is _taken over_ by this routine whether it
 319  * succeeds or fails (if it succeeds, the vbuf is reused for qu->vb).
 320  *
 321  * If failstat is nonzero then if we are successful in creating the query
 322  * it is immediately failed with code failstat (but _submit still succeds).
 323  *
 324  * ctx is copied byte-for-byte into the query.
 325  */
 326
 327 void *adns__alloc_interim(adns_query qu, size_t sz);
 328 /* Allocates some memory, and records which query it came from
 329  * and how much there was.
 330  *
 331  * If an error occurs in the query, all its memory is simply freed.
 332  *
 333  * If the query succeeds, one large buffer will be made which is
 334  * big enough for all these allocations, and then adns__alloc_final
 335  * will get memory from this buffer.
 336  *
 337  * _alloc_interim can fail (and return 0).
 338  * The caller must ensure that the query is failed.
 339  *
 340  * adns__alloc_interim_{only,fail}(qu,0) will not return 0,
 341  * but it will not necessarily return a distinct pointer each time.
 342  */
 343
 344 void *adns__alloc_mine(adns_query qu, size_t sz);
 345 /* Like _interim, but does not record the length for later
 346  * copying into the answer.  This just ensures that the memory
 347  * will be freed when we're done with the query.
 348  */
 349
 350 void *adns__alloc_final(adns_query qu, size_t sz);
 351 /* Cannot fail, and cannot return 0.
 352  */
 353
 354 void adns__makefinal_block(adns_query qu, void **blpp, size_t sz);
 355 void adns__makefinal_str(adns_query qu, char **strp);
 356
 357 void adns__reset_cnameonly(adns_query qu);
 358 /* Resets all of the memory management stuff etc. to
 359  * take account of only the CNAME.  Used when we find an error somewhere
 360  * and want to just report the error (with perhaps CNAME info), and also
 361  * when we're halfway through RRs in a datagram and discover that we
 362  * need to retry the query.
 363  */
 364
 365 void adns__query_done(adns_query qu);
 366 void adns__query_fail(adns_query qu, adns_status stat);
 367
 368 /* From reply.c: */
 369
 370 void adns__procdgram(adns_state ads, const byte *dgram, int len,
 371                      int serv, struct timeval now);
 372
 373 /* From types.c: */
 374
 375 const typeinfo *adns__findtype(adns_rrtype type);
 376
 377 /* From parse.c: */
 378
 379 typedef struct {
 380   adns_state ads;
 381   adns_query qu;
 382   int serv;
 383   const byte *dgram;
 384   int dglen, max, cbyte, namelen;
 385   int *dmend_r;
 386 } findlabel_state;
 387
 388 void adns__findlabel_start(findlabel_state *fls, adns_state ads,
 389                            int serv, adns_query qu,
 390                            const byte *dgram, int dglen, int max,
 391                            int dmbegin, int *dmend_rlater);
 392 /* Finds labels in a domain in a datagram.
 393  *
 394  * Call this routine first.
 395  * dmend_rlater may be null.  ads (and of course fls) may not be.
 396  * serv may be -1, qu may be null - they are for error reporting.
 397  */
 398
 399 adns_status adns__findlabel_next(findlabel_state *fls, int *lablen_r, int *labstart_r);
 400 /* Then, call this one repeatedly.
 401  *
 402  * It will return adns_s_ok if all is well, and tell you the length
 403  * and start of successive labels.  labstart_r may be null, but
 404  * lablen_r must not be.
 405  *
 406  * After the last label, it will return with *lablen_r zero.
 407  * Do not then call it again; instead, just throw away the findlabel_state.
 408  *
 409  * *dmend_rlater will have been set to point to the next part of
 410  * the datagram after the label (or after the uncompressed part,
 411  * if compression was used).  *namelen_rlater will have been set
 412  * to the length of the domain name (total length of labels plus
 413  * 1 for each intervening dot).
 414  *
 415  * If the datagram appears to be truncated, *lablen_r will be -1.
 416  * *dmend_rlater, *labstart_r and *namelen_r may contain garbage.
 417  * Do not call _next again.
 418  *
 419  * There may also be errors, in which case *dmend_rlater,
 420  * *namelen_rlater, *lablen_r and *labstart_r may contain garbage.
 421  * Do not then call findlabel_next again.
 422  */
 423
 424 adns_status adns__parse_domain(adns_state ads, int serv, adns_query qu,
 425                                vbuf *vb, int flags,
 426                                const byte *dgram, int dglen, int *cbyte_io, int max);
 427 /* vb must already have been initialised; it will be reset if necessary.
 428  * If there is truncation, vb->used will be set to 0; otherwise
 429  * (if there is no error) vb will be null-terminated.
 430  * If there is an error vb and *cbyte_io may be left indeterminate.
 431  *
 432  * serv may be -1 and qu may be 0 - they are used for error reporting only.
 433  */
 434
 435 adns_status adns__findrr(adns_query qu, int serv,
 436                          const byte *dgram, int dglen, int *cbyte_io,
 437                          int *type_r, int *class_r, int *rdlen_r, int *rdstart_r,
 438                          int *ownermatchedquery_r);
 439   /* Finds the extent and some of the contents of an RR in a datagram
 440    * and does some checks.  The datagram is *dgram, length dglen, and
 441    * the RR starts at *cbyte_io (which is updated afterwards to point
 442    * to the end of the RR).
 443    *
 444    * The type, class and RRdata length and start are returned iff
 445    * the corresponding pointer variables are not null.  type_r and
 446    * class_r may not be null.
 447    *
 448    * If ownermatchedquery_r != 0 then the owner domain of this
 449    * RR will be compared with that in the query (or, if the query
 450    * has gone to a CNAME lookup, with the canonical name).
 451    * In this case, *ownermatchedquery_r will be set to 0 or 1.
 452    * The query datagram (or CNAME datagram) MUST be valid and not truncated.
 453    *
 454    * If there is truncation then *type_r will be set to -1 and
 455    * *cbyte_io, *class_r, *rdlen_r, *rdstart_r and *eo_matched_r will be
 456    * undefined.
 457    *
 458    * qu must obviously be non-null.
 459    *
 460    * If an error is returned then *type_r will be undefined too.
 461    */
 462
 463 int vbuf__append_quoted1035(vbuf *vb, const byte *buf, int len);
 464
 465 /* From event.c: */
 466
 467 void adns__tcp_broken(adns_state ads, const char *what, const char *why);
 468 void adns__tcp_tryconnect(adns_state ads, struct timeval now);
 469
 470 void adns__autosys(adns_state ads, struct timeval now);
 471 /* Make all the system calls we want to if the application wants us to. */
 472
 473 /* Useful static inline functions: */
 474
 475 static inline void timevaladd(struct timeval *tv_io, long ms) {
 476   struct timeval tmp;
 477   assert(ms>=0);
 478   tmp= *tv_io;
 479   tmp.tv_usec += (ms%1000)*1000000;
 480   tmp.tv_sec += ms/1000;
 481   if (tmp.tv_usec >= 1000000) { tmp.tv_sec++; tmp.tv_usec -= 1000; }
 482   *tv_io= tmp;
 483 }
 484
 485 static inline int ctype_whitespace(int c) { return c==' ' || c=='\n' || c=='\t'; }
 486 static inline int ctype_digit(int c) { return c>='0' && c<='9'; }
 487 static inline int ctype_alpha(int c) {
 488   return (c >= 'a' && c <= 'z') || (c >= 'A' || c <= 'Z');
 489 }
 490
 491 /* Useful macros */
 492
 493 #define MEM_ROUND(sz) \
 494   (( ((sz)+sizeof(union maxalign)-1) / sizeof(union maxalign) ) \
 495    * sizeof(union maxalign) )
 496
 497 #define LIST_INIT(list) ((list).head= (list).tail= 0)
 498
 499 #define LIST_UNLINK_PART(list,node,part) \
 500   do { \
 501     if ((node)->back) (node)->back->part next= (node)->part next; \
 502       else                        (list).head= (node)->part next; \
 503     if ((node)->next) (node)->next->part back= (node)->part back; \
 504       else                        (list).tail= (node)->part back; \
 505   } while(0)
 506
 507 #define LIST_LINK_TAIL_PART(list,node,part) \
 508   do { \
 509     (node)->part next= 0; \
 510     (node)->part back= (list).tail; \
 511     if ((list).tail) (list).tail->part next= (node); else (list).part head= (node); \
 512     (list).tail= (node); \
 513   } while(0)
 514
 515 #define LIST_UNLINK(list,node) LIST_UNLINK_PART(list,node,)
 516 #define LIST_LINK_TAIL(list,node) LIST_LINK_TAIL_PART(list,node,)
 517
 518 #define GETIL_B(cb) (((dgram)[(cb)++]) & 0x0ff)
 519 #define GET_B(cb,tv) ((tv)= GETIL_B((cb)))
 520 #define GET_W(cb,tv) ((tv)=0, (tv)|=(GETIL_B((cb))<<8), (tv)|=GETIL_B(cb), (tv))
 521
 522 #endif