mdw@git.distorted.org.uk Git - adns/blob - src/query.c

   1 /*
   2  * query.c
   3  * - overall query management (allocation, completion)
   4  * - per-query memory management
   5  * - query submission and cancellation (user-visible and internal)
   6  */
   7 /*
   8  *  This file is part of adns, which is Copyright (C) 1997-1999 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 #include "internal.h"
  26
  27 #include <stdlib.h>
  28 #include <unistd.h>
  29 #include <errno.h>
  30
  31 #include <sys/time.h>
  32
  33 #include "internal.h"
  34
  35 static adns_query query_alloc(adns_state ads, const typeinfo *typei,
  36                               adns_queryflags flags, struct timeval now) {
  37   /* Allocate a virgin query and return it. */
  38   adns_query qu;
  39
  40   qu= malloc(sizeof(*qu));  if (!qu) return 0;
  41   qu->answer= malloc(sizeof(*qu->answer));  if (!qu->answer) { free(qu); return 0; }
  42
  43   qu->ads= ads;
  44   qu->state= query_tosend;
  45   qu->back= qu->next= qu->parent= 0;
  46   LIST_INIT(qu->children);
  47   LINK_INIT(qu->siblings);
  48   LIST_INIT(qu->allocations);
  49   qu->interim_allocd= 0;
  50   qu->preserved_allocd= 0;
  51   qu->final_allocspace= 0;
  52
  53   qu->typei= typei;
  54   qu->query_dgram= 0;
  55   qu->query_dglen= 0;
  56   adns__vbuf_init(&qu->vb);
  57
  58   qu->cname_dgram= 0;
  59   qu->cname_dglen= qu->cname_begin= 0;
  60
  61   adns__vbuf_init(&qu->search_vb);
  62   qu->search_origlen= qu->search_pos= qu->search_doneabs= 0;
  63
  64   qu->id= 0;
  65   qu->flags= flags;
  66   qu->udpretries= 0;
  67   qu->udpnextserver= 0;
  68   qu->udpsent= qu->tcpfailed= 0;
  69   timerclear(&qu->timeout);
  70   qu->expires= now.tv_sec + MAXTTLBELIEVE;
  71
  72   memset(&qu->ctx,0,sizeof(qu->ctx));
  73
  74   qu->answer->status= adns_s_ok;
  75   qu->answer->cname= qu->answer->owner= 0;
  76   qu->answer->type= typei->type;
  77   qu->answer->expires= -1;
  78   qu->answer->nrrs= 0;
  79   qu->answer->rrs.untyped= 0;
  80   qu->answer->rrsz= typei->rrsz;
  81
  82   return qu;
  83 }
  84
  85 static void query_submit(adns_state ads, adns_query qu,
  86                          const typeinfo *typei, vbuf *qumsg_vb, int id,
  87                          adns_queryflags flags, struct timeval now) {
  88   /* Fills in the query message in for a previously-allocated query,
  89    * and submits it.  Cannot fail.
  90    */
  91
  92   qu->vb= *qumsg_vb;
  93   adns__vbuf_init(qumsg_vb);
  94
  95   qu->query_dgram= malloc(qu->vb.used);
  96   if (!qu->query_dgram) { adns__query_fail(qu,adns_s_nomemory); return; }
  97
  98   qu->id= id;
  99   qu->query_dglen= qu->vb.used;
 100   memcpy(qu->query_dgram,qu->vb.buf,qu->vb.used);
 101
 102   adns__query_send(qu,now);
 103   adns__autosys(ads,now);
 104 }
 105
 106 adns_status adns__internal_submit(adns_state ads, adns_query *query_r,
 107                                   const typeinfo *typei, vbuf *qumsg_vb, int id,
 108                                   adns_queryflags flags, struct timeval now,
 109                                   const qcontext *ctx) {
 110   adns_query qu;
 111
 112   qu= query_alloc(ads,typei,flags,now);
 113   if (!qu) { adns__vbuf_free(qumsg_vb); return adns_s_nomemory; }
 114   *query_r= qu;
 115
 116   memcpy(&qu->ctx,ctx,sizeof(qu->ctx));
 117   query_submit(ads,qu, typei,qumsg_vb,id,flags,now);
 118
 119   return adns_s_ok;
 120 }
 121
 122 static void query_simple(adns_state ads, adns_query qu,
 123                          const char *owner, int ol,
 124                          const typeinfo *typei, adns_queryflags flags,
 125                          struct timeval now) {
 126   vbuf vb;
 127   int id;
 128   adns_status stat;
 129
 130   adns__vbuf_init(&vb);
 131
 132   stat= adns__mkquery(ads,&vb,&id, owner,ol, typei,flags);
 133   if (stat) { adns__query_fail(qu,stat); return; }
 134
 135   query_submit(ads,qu, typei,&vb,id, flags,now);
 136 }
 137
 138 void adns__search_next(adns_state ads, adns_query qu, struct timeval now) {
 139   const char *nextentry;
 140   adns_status stat;
 141
 142   if (qu->search_doneabs<0) {
 143     nextentry= 0;
 144     qu->search_doneabs= 1;
 145   } else {
 146     if (qu->search_pos >= ads->nsearchlist) {
 147       if (qu->search_doneabs) {
 148         stat= adns_s_nxdomain; goto x_fail;
 149         return;
 150       } else {
 151         nextentry= 0;
 152         qu->search_doneabs= 1;
 153       }
 154     } else {
 155       nextentry= ads->searchlist[qu->search_pos++];
 156     }
 157   }
 158
 159   qu->search_vb.used= qu->search_origlen;
 160   if (nextentry) {
 161     if (!adns__vbuf_append(&qu->search_vb,".",1) ||
 162         !adns__vbuf_appendstr(&qu->search_vb,nextentry)) {
 163       stat= adns_s_nomemory; goto x_fail;
 164     }
 165   }
 166
 167   free(qu->query_dgram);
 168   qu->query_dgram= 0; qu->query_dglen= 0;
 169
 170   query_simple(ads,qu, qu->search_vb.buf, qu->search_vb.used, qu->typei, qu->flags, now);
 171   return;
 172
 173 x_fail:
 174   adns__query_fail(qu,stat);
 175 }
 176
 177 static int save_owner(adns_query qu, const char *owner, int ol) {
 178   /* Returns 1 if OK, otherwise there was no memory. */
 179   adns_answer *ans;
 180
 181   ans= qu->answer;
 182   assert(!ans->owner);
 183
 184   ans->owner= adns__alloc_preserved(qu,ol+1);  if (!ans->owner) return 0;
 185
 186   memcpy(ans->owner,owner,ol);
 187   ans->owner[ol]= 0;
 188   return 1;
 189 }
 190
 191 int adns_submit(adns_state ads,
 192                 const char *owner,
 193                 adns_rrtype type,
 194                 adns_queryflags flags,
 195                 void *context,
 196                 adns_query *query_r) {
 197   int r, ol, ndots;
 198   adns_status stat;
 199   const typeinfo *typei;
 200   struct timeval now;
 201   adns_query qu;
 202   const char *p;
 203
 204   adns__consistency(ads,0,cc_entex);
 205
 206   typei= adns__findtype(type);
 207   if (!typei) return ENOSYS;
 208
 209   r= gettimeofday(&now,0); if (r) goto x_errno;
 210   qu= query_alloc(ads,typei,flags,now); if (!qu) goto x_errno;
 211
 212   qu->ctx.ext= context;
 213   qu->ctx.callback= 0;
 214   memset(&qu->ctx.info,0,sizeof(qu->ctx.info));
 215
 216   *query_r= qu;
 217
 218   ol= strlen(owner);
 219   if (!ol) { stat= adns_s_querydomaininvalid; goto x_adnsfail; }
 220   if (ol>DNS_MAXDOMAIN+1) { stat= adns_s_querydomaintoolong; goto x_adnsfail; }
 221
 222   if (ol>=1 && owner[ol-1]=='.' && (ol<2 || owner[ol-2]!='\\')) {
 223     flags &= ~adns_qf_search;
 224     ol--;
 225   }
 226
 227   if (flags & adns_qf_search) {
 228     r= adns__vbuf_append(&qu->search_vb,owner,ol);
 229     if (!r) { stat= adns_s_nomemory; goto x_adnsfail; }
 230
 231     for (ndots=0, p=owner; (p= strchr(p,'.')); p++, ndots++);
 232     qu->search_doneabs= (ndots >= ads->searchndots) ? -1 : 0;
 233     qu->search_origlen= ol;
 234     adns__search_next(ads,qu,now);
 235   } else {
 236     if (flags & adns_qf_owner) {
 237       if (!save_owner(qu,owner,ol)) { stat= adns_s_nomemory; goto x_adnsfail; }
 238     }
 239     query_simple(ads,qu, owner,ol, typei,flags, now);
 240   }
 241   adns__consistency(ads,qu,cc_entex);
 242   return 0;
 243
 244  x_adnsfail:
 245   adns__query_fail(qu,stat);
 246   adns__consistency(ads,qu,cc_entex);
 247   return 0;
 248
 249  x_errno:
 250   r= errno;
 251   assert(r);
 252   adns__consistency(ads,0,cc_entex);
 253   return r;
 254 }
 255
 256 int adns_synchronous(adns_state ads,
 257                      const char *owner,
 258                      adns_rrtype type,
 259                      adns_queryflags flags,
 260                      adns_answer **answer_r) {
 261   adns_query qu;
 262   int r;
 263
 264   r= adns_submit(ads,owner,type,flags,0,&qu);
 265   if (r) return r;
 266
 267   r= adns_wait(ads,&qu,answer_r,0);
 268   if (r) adns_cancel(qu);
 269
 270   return r;
 271 }
 272
 273 static void *alloc_common(adns_query qu, size_t sz) {
 274   allocnode *an;
 275
 276   if (!sz) return qu; /* Any old pointer will do */
 277   assert(!qu->final_allocspace);
 278   an= malloc(MEM_ROUND(MEM_ROUND(sizeof(*an)) + sz));
 279   if (!an) return 0;
 280   LIST_LINK_TAIL(qu->allocations,an);
 281   return (byte*)an + MEM_ROUND(sizeof(*an));
 282 }
 283
 284 void *adns__alloc_interim(adns_query qu, size_t sz) {
 285   void *rv;
 286
 287   sz= MEM_ROUND(sz);
 288   rv= alloc_common(qu,sz);
 289   if (!rv) return 0;
 290   qu->interim_allocd += sz;
 291   return rv;
 292 }
 293
 294 void *adns__alloc_preserved(adns_query qu, size_t sz) {
 295   void *rv;
 296
 297   sz= MEM_ROUND(sz);
 298   rv= adns__alloc_interim(qu,sz);
 299   if (!rv) return 0;
 300   qu->preserved_allocd += sz;
 301   return rv;
 302 }
 303
 304 void *adns__alloc_mine(adns_query qu, size_t sz) {
 305   return alloc_common(qu,MEM_ROUND(sz));
 306 }
 307
 308 void adns__transfer_interim(adns_query from, adns_query to, void *block, size_t sz) {
 309   allocnode *an;
 310
 311   if (!block) return;
 312   an= (void*)((byte*)block - MEM_ROUND(sizeof(*an)));
 313
 314   assert(!to->final_allocspace);
 315   assert(!from->final_allocspace);
 316
 317   LIST_UNLINK(from->allocations,an);
 318   LIST_LINK_TAIL(to->allocations,an);
 319
 320   from->interim_allocd -= sz;
 321   to->interim_allocd += sz;
 322
 323   if (to->expires > from->expires) to->expires= from->expires;
 324 }
 325
 326 void *adns__alloc_final(adns_query qu, size_t sz) {
 327   /* When we're in the _final stage, we _subtract_ from interim_alloc'd
 328    * each allocation, and use final_allocspace to point to the next free
 329    * bit.
 330    */
 331   void *rp;
 332
 333   sz= MEM_ROUND(sz);
 334   rp= qu->final_allocspace;
 335   assert(rp);
 336   qu->interim_allocd -= sz;
 337   assert(qu->interim_allocd>=0);
 338   qu->final_allocspace= (byte*)rp + sz;
 339   return rp;
 340 }
 341
 342 static void cancel_children(adns_query qu) {
 343   adns_query cqu, ncqu;
 344
 345   for (cqu= qu->children.head; cqu; cqu= ncqu) {
 346     ncqu= cqu->siblings.next;
 347     adns_cancel(cqu);
 348   }
 349   LIST_INIT(qu->children);
 350 }
 351
 352 void adns__reset_preserved(adns_query qu) {
 353   assert(!qu->final_allocspace);
 354   cancel_children(qu);
 355   qu->answer->nrrs= 0;
 356   qu->answer->rrs.untyped= 0;
 357   qu->interim_allocd= qu->preserved_allocd;
 358 }
 359
 360 static void free_query_allocs(adns_query qu) {
 361   allocnode *an, *ann;
 362
 363   cancel_children(qu);
 364   for (an= qu->allocations.head; an; an= ann) { ann= an->next; free(an); }
 365   adns__vbuf_free(&qu->vb);
 366 }
 367
 368 void adns_cancel(adns_query qu) {
 369   adns_state ads;
 370
 371   ads= qu->ads;
 372   adns__consistency(ads,qu,cc_entex);
 373   switch (qu->state) {
 374   case query_tosend: case query_tcpwait: case query_tcpsent:
 375     LIST_UNLINK(ads->timew,qu);
 376     break;
 377   case query_child:
 378     LIST_UNLINK(ads->childw,qu);
 379     break;
 380   case query_done:
 381     LIST_UNLINK(ads->output,qu);
 382     break;
 383   default:
 384     abort();
 385   }
 386   free_query_allocs(qu);
 387   free(qu->answer);
 388   free(qu);
 389   adns__consistency(ads,0,cc_entex);
 390 }
 391
 392 void adns__update_expires(adns_query qu, unsigned long ttl, struct timeval now) {
 393   time_t max;
 394
 395   assert(ttl <= MAXTTLBELIEVE);
 396   max= now.tv_sec + ttl;
 397   if (qu->expires < max) return;
 398   qu->expires= max;
 399 }
 400
 401 static void makefinal_query(adns_query qu) {
 402   adns_answer *ans;
 403   int rrn;
 404
 405   ans= qu->answer;
 406
 407   if (qu->interim_allocd) {
 408     ans= realloc(qu->answer, MEM_ROUND(MEM_ROUND(sizeof(*ans)) + qu->interim_allocd));
 409     if (!ans) goto x_nomem;
 410     qu->answer= ans;
 411   }
 412
 413   qu->final_allocspace= (byte*)ans + MEM_ROUND(sizeof(*ans));
 414   adns__makefinal_str(qu,&ans->cname);
 415   adns__makefinal_str(qu,&ans->owner);
 416
 417   if (ans->nrrs) {
 418     adns__makefinal_block(qu, &ans->rrs.untyped, ans->nrrs*ans->rrsz);
 419
 420     for (rrn=0; rrn<ans->nrrs; rrn++)
 421       qu->typei->makefinal(qu, ans->rrs.bytes + rrn*ans->rrsz);
 422   }
 423
 424   free_query_allocs(qu);
 425   return;
 426
 427  x_nomem:
 428   qu->preserved_allocd= 0;
 429   qu->answer->cname= 0;
 430   qu->answer->owner= 0;
 431   adns__reset_preserved(qu); /* (but we just threw away the preserved stuff) */
 432
 433   qu->answer->status= adns_s_nomemory;
 434   free_query_allocs(qu);
 435 }
 436
 437 void adns__query_done(adns_query qu) {
 438   adns_answer *ans;
 439   adns_query parent;
 440
 441   cancel_children(qu);
 442
 443   qu->id= -1;
 444   ans= qu->answer;
 445
 446   if (qu->flags & adns_qf_owner && qu->flags & adns_qf_search &&
 447       ans->status != adns_s_nomemory) {
 448     if (!save_owner(qu, qu->search_vb.buf, qu->search_vb.used)) {
 449       adns__query_fail(qu,adns_s_nomemory);
 450       return;
 451     }
 452   }
 453
 454   if (ans->nrrs && qu->typei->diff_needswap) {
 455     if (!adns__vbuf_ensure(&qu->vb,qu->typei->rrsz)) {
 456       adns__query_fail(qu,adns_s_nomemory);
 457       return;
 458     }
 459     adns__isort(ans->rrs.bytes, ans->nrrs, ans->rrsz,
 460                 qu->vb.buf,
 461                 (int(*)(void*, const void*, const void*))qu->typei->diff_needswap,
 462                 qu->ads);
 463   }
 464
 465   ans->expires= qu->expires;
 466   parent= qu->parent;
 467   if (parent) {
 468     LIST_UNLINK_PART(parent->children,qu,siblings.);
 469     LIST_UNLINK(qu->ads->childw,parent);
 470     qu->ctx.callback(parent,qu);
 471     free_query_allocs(qu);
 472     free(qu);
 473   } else {
 474     makefinal_query(qu);
 475     LIST_LINK_TAIL(qu->ads->output,qu);
 476   }
 477   qu->state= query_done;
 478 }
 479
 480 void adns__query_fail(adns_query qu, adns_status stat) {
 481   adns__reset_preserved(qu);
 482   qu->answer->status= stat;
 483   adns__query_done(qu);
 484 }
 485
 486 void adns__makefinal_str(adns_query qu, char **strp) {
 487   int l;
 488   char *before, *after;
 489
 490   before= *strp;
 491   if (!before) return;
 492   l= strlen(before)+1;
 493   after= adns__alloc_final(qu,l);
 494   memcpy(after,before,l);
 495   *strp= after;
 496 }
 497
 498 void adns__makefinal_block(adns_query qu, void **blpp, size_t sz) {
 499   void *before, *after;
 500
 501   before= *blpp;
 502   if (!before) return;
 503   after= adns__alloc_final(qu,sz);
 504   memcpy(after,before,sz);
 505   *blpp= after;
 506 }