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