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 } typeinfo;
 112
 113 typedef struct allocnode {
 114   struct allocnode *next;
 115 } allocnode;
 116
 117 union maxalign {
 118   byte d[1];
 119   struct in_addr ia;
 120   long l;
 121   void *p;
 122   void (*fp)(void);
 123   union maxalign *up;
 124 } data;
 125
 126 struct adns__query {
 127   adns_state ads;
 128   enum { query_udp, query_tcpwait, query_tcpsent, query_child, query_done } state;
 129   adns_query back, next, parent;
 130   struct { adns_query head, tail; } children;
 131   struct { adns_query back, next; } siblings;
 132   struct allocnode *allocations;
 133   int interim_allocd;
 134   void *final_allocspace;
 135
 136   const typeinfo *typei;
 137   char *query_dgram;
 138   int query_dglen;
 139
 140   vbuf vb;
 141   /* General-purpose messing-about buffer.
 142    * Wherever a `big' interface is crossed, this may be corrupted/changed
 143    * unless otherwise specified.
 144    */
 145
 146   adns_answer *answer;
 147   /* This is allocated when a query is submitted, to avoid being unable
 148    * to relate errors to queries if we run out of memory.  During
 149    * query processing status, rrs is 0.  cname is set if
 150    * we found a cname (this corresponds to cname_dgram in the query
 151    * structure).  type is set from the word go.  nrrs and rrs
 152    * are set together, when we find how many rrs there are.
 153    */
 154
 155   byte *cname_dgram;
 156   int cname_dglen, cname_begin;
 157   /* If non-0, has been allocated using . */
 158
 159   int id, flags, udpretries;
 160   int udpnextserver;
 161   unsigned long udpsent, tcpfailed; /* bitmap indexed by server */
 162   struct timeval timeout;
 163   qcontext context;
 164
 165   /* Possible states:
 166    *
 167    *  state   Queue   child  id   nextudpserver  sentudp     failedtcp
 168    *
 169    *  udp     NONE    null   >=0  0              zero        zero
 170    *  udp     timew   null   >=0  any            nonzero     zero
 171    *  udp     NONE    null   >=0  any            nonzero     zero
 172    *
 173    *  tcpwait timew   null   >=0  irrelevant     zero        any
 174    *  tcpsent timew   null   >=0  irrelevant     zero        any
 175    *
 176    *  child   childw  set    >=0  irrelevant     irrelevant  irrelevant
 177    *  done    output  null   -1   irrelevant     irrelevant  irrelevant
 178    *
 179    *                          +------------------------+
 180    *             START -----> |      udp/NONE          |
 181    *                          +------------------------+
 182    *                         /                       |\  \
 183    *        too big for UDP /             UDP timeout  \  \ send via UDP
 184    *        do this ASAP!  /              more retries  \  \   do this ASAP!
 185    *                     |_                  desired     \  _|
 186    *              +---------------+                     +-----------+
 187    *              | tcpwait/timew | ____                | udp/timew |
 188    *              +---------------+     \               +-----------+
 189    *                    |  ^             |                 | |
 190    *     TCP conn'd;    |  | TCP died    |                 | |
 191    *     send via TCP   |  | more        |     UDP timeout | |
 192    *     do this ASAP!  |  | servers     |      no more    | |
 193    *                    v  | to try      |      retries    | |
 194    *              +---------------+      |      desired    | |
 195    *              | tcpsent/timew | ____ |                 | |
 196    *              +---------------+     \|                 | |
 197    *                  \   \ TCP died     | TCP             | |
 198    *                   \   \ no more     | timeout         / |
 199    *                    \   \ servers    |                /  |
 200    *                     \   \ to try    |               /   |
 201    *                  got \   \          v             |_    / got
 202    *                 reply \   _| +------------------+      / reply
 203    *                        \     | done/output FAIL |     /
 204    *                         \    +------------------+    /
 205    *                          \                          /
 206    *                           _|                      |_
 207    *                             (..... got reply ....)
 208    *                              /                   \
 209    *        need child query/ies /                     \ no child query
 210    *                            /                       \
 211    *                          |_                         _|
 212    *                +--------------+                   +----------------+
 213    *                | child/childw | ----------------> | done/output OK |
 214    *                +--------------+  children done    +----------------+
 215    */
 216 };
 217
 218 struct adns__state {
 219   adns_initflags iflags;
 220   FILE *diagfile;
 221   struct { adns_query head, tail; } timew, childw, output;
 222   int nextid, udpsocket, tcpsocket;
 223   vbuf tcpsend, tcprecv;
 224   int nservers, tcpserver;
 225   enum adns__tcpstate { server_disconnected, server_connecting, server_ok } tcpstate;
 226   struct timeval tcptimeout;
 227   struct server {
 228     struct in_addr addr;
 229   } servers[MAXSERVERS];
 230 };
 231
 232 /* From setup.c: */
 233
 234 int adns__setnonblock(adns_state ads, int fd); /* => errno value */
 235
 236 /* From general.c: */
 237
 238 void adns__vdiag(adns_state ads, const char *pfx, adns_initflags prevent,
 239                  int serv, adns_query qu, const char *fmt, va_list al);
 240
 241 void adns__debug(adns_state ads, int serv, adns_query qu,
 242                  const char *fmt, ...) PRINTFFORMAT(4,5);
 243 void adns__warn(adns_state ads, int serv, adns_query qu,
 244                 const char *fmt, ...) PRINTFFORMAT(4,5);
 245 void adns__diag(adns_state ads, int serv, adns_query qu,
 246                 const char *fmt, ...) PRINTFFORMAT(4,5);
 247
 248 int adns__vbuf_ensure(vbuf *vb, int want);
 249 int adns__vbuf_appendstr(vbuf *vb, const char *data); /* does not include nul */
 250 int adns__vbuf_append(vbuf *vb, const byte *data, int len);
 251 /* 1=>success, 0=>realloc failed */
 252 void adns__vbuf_appendq(vbuf *vb, const byte *data, int len);
 253 void adns__vbuf_init(vbuf *vb);
 254 void adns__vbuf_free(vbuf *vb);
 255
 256 const char *adns__diag_domain(adns_state ads, int serv, adns_query qu, vbuf *vb,
 257                               int flags, const byte *dgram, int dglen, int cbyte);
 258 /* Unpicks a domain in a datagram and returns a string suitable for
 259  * printing it as.  Never fails - if an error occurs, it will
 260  * return some kind of string describing the error.
 261  *
 262  * serv may be -1 and qu may be 0.  vb must have been initialised,
 263  * and will be left in an arbitrary consistent state.
 264  *
 265  * Returns either vb->buf, or a pointer to a string literal.  Do not modify
 266  * vb before using the return value.
 267  */
 268
 269 /* From transmit.c: */
 270
 271 adns_status adns__mkquery(adns_state ads, vbuf *vb, int *id_r,
 272                           const char *owner, int ol,
 273                           const typeinfo *typei, adns_queryflags flags);
 274 /* Assembles a query packet in vb, and returns id at *id_r. */
 275
 276 void adns__query_tcp(adns_query qu, struct timeval now);
 277 /* Query must be in state tcpwait/timew; it will be moved to a new state
 278  * if possible and no further processing can be done on it for now.
 279  * (Resulting state is one of tcpwait/timew (if server not connected),
 280  *  tcpsent/timew, child/childw or done/output.)
 281  *
 282  * adns__tcp_tryconnect should already have been called - _tcp
 283  * will only use an existing connection (if there is one), which it
 284  * may break.  If the conn list lost then the caller is responsible for any
 285  * reestablishment and retry.
 286  */
 287
 288 void adns__query_udp(adns_query qu, struct timeval now);
 289 /* Query must be in state udp/NONE; it will be moved to a new state,
 290  * and no further processing can be done on it for now.
 291  * (Resulting state is one of udp/timew, tcpwait/timew (if server not connected),
 292  *  tcpsent/timew, child/childw or done/output.)
 293  */
 294
 295 /* From query.c: */
 296
 297 int adns__internal_submit(adns_state ads, adns_query *query_r,
 298                           const typeinfo *typei, vbuf *qumsg_vb, int id,
 299                           adns_queryflags flags, struct timeval now,
 300                           adns_status failstat, const qcontext *ctx);
 301 /* Submits a query (for internal use, called during external submits).
 302  *
 303  * The new query is returned in *query_r, or we return adns_s_nomemory.
 304  *
 305  * The query datagram should already have been assembled in qumsg_vb;
 306  * the memory for it is _taken over_ by this routine whether it
 307  * succeeds or fails (if it succeeds, the vbuf is reused for qu->vb).
 308  *
 309  * If failstat is nonzero then if we are successful in creating the query
 310  * it is immediately failed with code failstat (but _submit still succeds).
 311  *
 312  * ctx is copied byte-for-byte into the query.
 313  */
 314
 315 void *adns__alloc_interim(adns_query qu, size_t sz);
 316 /* Allocates some memory, and records which query it came from
 317  * and how much there was.
 318  *
 319  * If an error occurs in the query, all its memory is simply freed.
 320  *
 321  * If the query succeeds, one large buffer will be made which is
 322  * big enough for all these allocations, and then adns__alloc_final
 323  * will get memory from this buffer.
 324  *
 325  * _alloc_interim can fail, in which case it will fail the query too,
 326  * so nothing more need be done with it.
 327  *
 328  * adns__alloc_interim(qu,0) will not return 0, but it will not
 329  * necessarily return a distinct pointer each time.
 330  */
 331
 332 void *adns__alloc_mine(adns_query qu, size_t sz);
 333 /* Like _interim, but does not record the length for later
 334  * copying into the answer.  This just ensures that the memory
 335  * will be freed when we're done with the query.
 336  */
 337
 338 void *adns__alloc_final(adns_query qu, size_t sz);
 339 /* Cannot fail, and cannot return 0.
 340  */
 341
 342 void adns__makefinal_block(adns_query qu, void **blpp, size_t sz);
 343 void adns__makefinal_str(adns_query qu, char **strp);
 344
 345 void adns__reset_cnameonly(adns_query qu);
 346 /* Resets all of the memory management stuff etc. to
 347  * take account of only the CNAME.  Used when we find an error somewhere
 348  * and want to just report the error (with perhaps CNAME info), and also
 349  * when we're halfway through RRs in a datagram and discover that we
 350  * need to retry the query.
 351  */
 352
 353 void adns__query_done(adns_query qu);
 354 void adns__query_fail(adns_query qu, adns_status stat);
 355
 356 /* From reply.c: */
 357
 358 void adns__procdgram(adns_state ads, const byte *dgram, int len,
 359                      int serv, struct timeval now);
 360
 361 /* From types.c: */
 362
 363 const typeinfo *adns__findtype(adns_rrtype type);
 364
 365 /* From parse.c: */
 366
 367 typedef struct {
 368   adns_state ads;
 369   adns_query qu;
 370   int serv;
 371   const byte *dgram;
 372   int dglen, max, cbyte, namelen;
 373   int *dmend_r;
 374 } findlabel_state;
 375
 376 void adns__findlabel_start(findlabel_state *fls, adns_state ads,
 377                            int serv, adns_query qu,
 378                            const byte *dgram, int dglen, int max,
 379                            int dmbegin, int *dmend_rlater);
 380 /* Finds labels in a domain in a datagram.
 381  *
 382  * Call this routine first.
 383  * dmend_rlater may be null.  ads (and of course fls) may not be.
 384  * serv may be -1, qu may be null - they are for error reporting.
 385  */
 386
 387 adns_status adns__findlabel_next(findlabel_state *fls, int *lablen_r, int *labstart_r);
 388 /* Then, call this one repeatedly.
 389  *
 390  * It will return adns_s_ok if all is well, and tell you the length
 391  * and start of successive labels.  labstart_r may be null, but
 392  * lablen_r must not be.
 393  *
 394  * After the last label, it will return with *lablen_r zero.
 395  * Do not then call it again; instead, just throw away the findlabel_state.
 396  *
 397  * *dmend_rlater will have been set to point to the next part of
 398  * the datagram after the label (or after the uncompressed part,
 399  * if compression was used).  *namelen_rlater will have been set
 400  * to the length of the domain name (total length of labels plus
 401  * 1 for each intervening dot).
 402  *
 403  * If the datagram appears to be truncated, *lablen_r will be -1.
 404  * *dmend_rlater, *labstart_r and *namelen_r may contain garbage.
 405  * Do not call _next again.
 406  *
 407  * There may also be errors, in which case *dmend_rlater,
 408  * *namelen_rlater, *lablen_r and *labstart_r may contain garbage.
 409  * Do not then call findlabel_next again.
 410  */
 411
 412 adns_status adns__parse_domain(adns_state ads, int serv, adns_query qu,
 413                                vbuf *vb, int flags,
 414                                const byte *dgram, int dglen, int *cbyte_io, int max);
 415 /* vb must already have been initialised; it will be reset if necessary.
 416  * If there is truncation, vb->used will be set to 0; otherwise
 417  * (if there is no error) vb will be null-terminated.
 418  * If there is an error vb and *cbyte_io may be left indeterminate.
 419  *
 420  * serv may be -1 and qu may be 0 - they are used for error reporting only.
 421  */
 422
 423 adns_status adns__findrr(adns_query qu, int serv,
 424                          const byte *dgram, int dglen, int *cbyte_io,
 425                          int *type_r, int *class_r, int *rdlen_r, int *rdstart_r,
 426                          int *ownermatchedquery_r);
 427   /* Finds the extent and some of the contents of an RR in a datagram
 428    * and does some checks.  The datagram is *dgram, length dglen, and
 429    * the RR starts at *cbyte_io (which is updated afterwards to point
 430    * to the end of the RR).
 431    *
 432    * The type, class and RRdata length and start are returned iff
 433    * the corresponding pointer variables are not null.  type_r and
 434    * class_r may not be null.
 435    *
 436    * If ownermatchedquery_r != 0 then the owner domain of this
 437    * RR will be compared with that in the query (or, if the query
 438    * has gone to a CNAME lookup, with the canonical name).
 439    * In this case, *ownermatchedquery_r will be set to 0 or 1.
 440    * The query datagram (or CNAME datagram) MUST be valid and not truncated.
 441    *
 442    * If there is truncation then *type_r will be set to -1 and
 443    * *cbyte_io, *class_r, *rdlen_r, *rdstart_r and *eo_matched_r will be
 444    * undefined.
 445    *
 446    * qu must obviously be non-null.
 447    *
 448    * If an error is returned then *type_r will be undefined too.
 449    */
 450
 451 int vbuf__append_quoted1035(vbuf *vb, const byte *buf, int len);
 452
 453 /* From event.c: */
 454
 455 void adns__tcp_broken(adns_state ads, const char *what, const char *why);
 456 void adns__tcp_tryconnect(adns_state ads, struct timeval now);
 457
 458 void adns__autosys(adns_state ads, struct timeval now);
 459 /* Make all the system calls we want to if the application wants us to. */
 460
 461 /* Useful static inline functions: */
 462
 463 static inline void timevaladd(struct timeval *tv_io, long ms) {
 464   struct timeval tmp;
 465   assert(ms>=0);
 466   tmp= *tv_io;
 467   tmp.tv_usec += (ms%1000)*1000000;
 468   tmp.tv_sec += ms/1000;
 469   if (tmp.tv_usec >= 1000000) { tmp.tv_sec++; tmp.tv_usec -= 1000; }
 470   *tv_io= tmp;
 471 }
 472
 473 static inline int ctype_whitespace(int c) { return c==' ' || c=='\n' || c=='\t'; }
 474 static inline int ctype_digit(int c) { return c>='0' && c<='9'; }
 475 static inline int ctype_alpha(int c) {
 476   return (c >= 'a' && c <= 'z') || (c >= 'A' || c <= 'Z');
 477 }
 478
 479 /* Useful macros */
 480
 481 #define MEM_ROUND(sz) \
 482   (( ((sz)+sizeof(union maxalign)-1) / sizeof(union maxalign) ) \
 483    * sizeof(union maxalign) )
 484
 485 #define LIST_INIT(list) ((list).head= (list).tail= 0)
 486
 487 #define LIST_UNLINK_PART(list,node,part) \
 488   do { \
 489     if ((node)->back) (node)->back->part next= (node)->part next; \
 490       else                        (list).head= (node)->part next; \
 491     if ((node)->next) (node)->next->part back= (node)->part back; \
 492       else                        (list).tail= (node)->part back; \
 493   } while(0)
 494
 495 #define LIST_LINK_TAIL_PART(list,node,part) \
 496   do { \
 497     (node)->part next= 0; \
 498     (node)->part back= (list).tail; \
 499     if ((list).tail) (list).tail->part next= (node); else (list).part head= (node); \
 500     (list).tail= (node); \
 501   } while(0)
 502
 503 #define LIST_UNLINK(list,node) LIST_UNLINK_PART(list,node,)
 504 #define LIST_LINK_TAIL(list,node) LIST_LINK_TAIL_PART(list,node,)
 505
 506 #define GETIL_B(cb) (((dgram)[(cb)++]) & 0x0ff)
 507 #define GET_B(cb,tv) ((tv)= GETIL_B((cb)))
 508 #define GET_W(cb,tv) ((tv)=0, (tv)|=(GETIL_B((cb))<<8), (tv)|=GETIL_B(cb), (tv))
 509
 510 #endif