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
   9  *    Copyright (C) 1997-1999 Ian Jackson <ian@davenant.greenend.org.uk>
  10  *
  11  *  It is part of adns, which is
  12  *    Copyright (C) 1997-1999 Ian Jackson <ian@davenant.greenend.org.uk>
  13  *    Copyright (C) 1999 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 #include "internal.h"
  31
  32 #include <stdlib.h>
  33 #include <unistd.h>
  34 #include <errno.h>
  35
  36 #include <sys/time.h>
  37
  38 #include "internal.h"
  39
  40 static adns_query query_alloc(adns_state ads, const typeinfo *typei,
  41                               adns_queryflags flags, struct timeval now) {
  42   /* Allocate a virgin query and return it. */
  43   adns_query qu;
  44
  45   qu= malloc(sizeof(*qu));  if (!qu) return 0;
  46   qu->answer= malloc(sizeof(*qu->answer));  if (!qu->answer) { free(qu); return 0; }
  47
  48   qu->ads= ads;
  49   qu->state= query_tosend;
  50   qu->back= qu->next= qu->parent= 0;
  51   LIST_INIT(qu->children);
  52   LINK_INIT(qu->siblings);
  53   LIST_INIT(qu->allocations);
  54   qu->interim_allocd= 0;
  55   qu->preserved_allocd= 0;
  56   qu->final_allocspace= 0;
  57
  58   qu->typei= typei;
  59   qu->query_dgram= 0;
  60   qu->query_dglen= 0;
  61   adns__vbuf_init(&qu->vb);
  62
  63   qu->cname_dgram= 0;
  64   qu->cname_dglen= qu->cname_begin= 0;
  65
  66   adns__vbuf_init(&qu->search_vb);
  67   qu->search_origlen= qu->search_pos= qu->search_doneabs= 0;
  68
  69   qu->id= 0;
  70   qu->flags= flags;
  71   qu->udpretries= 0;
  72   qu->udpnextserver= 0;
  73   qu->udpsent= qu->tcpfailed= 0;
  74   timerclear(&qu->timeout);
  75   qu->expires= now.tv_sec + MAXTTLBELIEVE;
  76
  77   memset(&qu->ctx,0,sizeof(qu->ctx));
  78
  79   qu->answer->status= adns_s_ok;
  80   qu->answer->cname= qu->answer->owner= 0;
  81   qu->answer->type= typei->type;
  82   qu->answer->expires= -1;
  83   qu->answer->nrrs= 0;
  84   qu->answer->rrs.untyped= 0;
  85   qu->answer->rrsz= typei->rrsz;
  86
  87   return qu;
  88 }
  89
  90 static void query_submit(adns_state ads, adns_query qu,
  91                          const typeinfo *typei, vbuf *qumsg_vb, int id,
  92                          adns_queryflags flags, struct timeval now) {
  93   /* Fills in the query message in for a previously-allocated query,
  94    * and submits it.  Cannot fail.
  95    */
  96
  97   qu->vb= *qumsg_vb;
  98   adns__vbuf_init(qumsg_vb);
  99
 100   qu->query_dgram= malloc(qu->vb.used);
 101   if (!qu->query_dgram) { adns__query_fail(qu,adns_s_nomemory); return; }
 102
 103   qu->id= id;
 104   qu->query_dglen= qu->vb.used;
 105   memcpy(qu->query_dgram,qu->vb.buf,qu->vb.used);
 106
 107   adns__query_send(qu,now);
 108   adns__autosys(ads,now);
 109 }
 110
 111 adns_status adns__internal_submit(adns_state ads, adns_query *query_r,
 112                                   const typeinfo *typei, vbuf *qumsg_vb, int id,
 113                                   adns_queryflags flags, struct timeval now,
 114                                   const qcontext *ctx) {
 115   adns_query qu;
 116
 117   qu= query_alloc(ads,typei,flags,now);
 118   if (!qu) { adns__vbuf_free(qumsg_vb); return adns_s_nomemory; }
 119   *query_r= qu;
 120
 121   memcpy(&qu->ctx,ctx,sizeof(qu->ctx));
 122   query_submit(ads,qu, typei,qumsg_vb,id,flags,now);
 123
 124   return adns_s_ok;
 125 }
 126
 127 static void query_simple(adns_state ads, adns_query qu,
 128                          const char *owner, int ol,
 129                          const typeinfo *typei, adns_queryflags flags,
 130                          struct timeval now) {
 131   vbuf vb;
 132   int id;
 133   adns_status stat;
 134
 135   adns__vbuf_init(&vb);
 136
 137   stat= adns__mkquery(ads,&vb,&id, owner,ol, typei,flags);
 138   if (stat) { adns__query_fail(qu,stat); return; }
 139
 140   query_submit(ads,qu, typei,&vb,id, flags,now);
 141 }
 142
 143 void adns__search_next(adns_state ads, adns_query qu, struct timeval now) {
 144   const char *nextentry;
 145   adns_status stat;
 146
 147   if (qu->search_doneabs<0) {
 148     nextentry= 0;
 149     qu->search_doneabs= 1;
 150   } else {
 151     if (qu->search_pos >= ads->nsearchlist) {
 152       if (qu->search_doneabs) {
 153         stat= adns_s_nxdomain; goto x_fail;
 154         return;
 155       } else {
 156         nextentry= 0;
 157         qu->search_doneabs= 1;
 158       }
 159     } else {
 160       nextentry= ads->searchlist[qu->search_pos++];
 161     }
 162   }
 163
 164   qu->search_vb.used= qu->search_origlen;
 165   if (nextentry) {
 166     if (!adns__vbuf_append(&qu->search_vb,".",1) ||
 167         !adns__vbuf_appendstr(&qu->search_vb,nextentry)) {
 168       stat= adns_s_nomemory; goto x_fail;
 169     }
 170   }
 171
 172   free(qu->query_dgram);
 173   qu->query_dgram= 0; qu->query_dglen= 0;
 174
 175   query_simple(ads,qu, qu->search_vb.buf, qu->search_vb.used, qu->typei, qu->flags, now);
 176   return;
 177
 178 x_fail:
 179   adns__query_fail(qu,stat);
 180 }
 181
 182 static int save_owner(adns_query qu, const char *owner, int ol) {
 183   /* Returns 1 if OK, otherwise there was no memory. */
 184   adns_answer *ans;
 185
 186   ans= qu->answer;
 187   assert(!ans->owner);
 188
 189   ans->owner= adns__alloc_preserved(qu,ol+1);  if (!ans->owner) return 0;
 190
 191   memcpy(ans->owner,owner,ol);
 192   ans->owner[ol]= 0;
 193   return 1;
 194 }
 195
 196 int adns_submit(adns_state ads,
 197                 const char *owner,
 198                 adns_rrtype type,
 199                 adns_queryflags flags,
 200                 void *context,
 201                 adns_query *query_r) {
 202   int r, ol, ndots;
 203   adns_status stat;
 204   const typeinfo *typei;
 205   struct timeval now;
 206   adns_query qu;
 207   const char *p;
 208
 209   adns__consistency(ads,0,cc_entex);
 210
 211   typei= adns__findtype(type);
 212   if (!typei) return ENOSYS;
 213
 214   r= gettimeofday(&now,0); if (r) goto x_errno;
 215   qu= query_alloc(ads,typei,flags,now); if (!qu) goto x_errno;
 216
 217   qu->ctx.ext= context;
 218   qu->ctx.callback= 0;
 219   memset(&qu->ctx.info,0,sizeof(qu->ctx.info));
 220
 221   *query_r= qu;
 222
 223   ol= strlen(owner);
 224   if (!ol) { stat= adns_s_querydomaininvalid; goto x_adnsfail; }
 225   if (ol>DNS_MAXDOMAIN+1) { stat= adns_s_querydomaintoolong; goto x_adnsfail; }
 226
 227   if (ol>=1 && owner[ol-1]=='.' && (ol<2 || owner[ol-2]!='\\')) {
 228     flags &= ~adns_qf_search;
 229     ol--;
 230   }
 231
 232   if (flags & adns_qf_search) {
 233     r= adns__vbuf_append(&qu->search_vb,owner,ol);
 234     if (!r) { stat= adns_s_nomemory; goto x_adnsfail; }
 235
 236     for (ndots=0, p=owner; (p= strchr(p,'.')); p++, ndots++);
 237     qu->search_doneabs= (ndots >= ads->searchndots) ? -1 : 0;
 238     qu->search_origlen= ol;
 239     adns__search_next(ads,qu,now);
 240   } else {
 241     if (flags & adns_qf_owner) {
 242       if (!save_owner(qu,owner,ol)) { stat= adns_s_nomemory; goto x_adnsfail; }
 243     }
 244     query_simple(ads,qu, owner,ol, typei,flags, now);
 245   }
 246   adns__consistency(ads,qu,cc_entex);
 247   return 0;
 248
 249  x_adnsfail:
 250   adns__query_fail(qu,stat);
 251   adns__consistency(ads,qu,cc_entex);
 252   return 0;
 253
 254  x_errno:
 255   r= errno;
 256   assert(r);
 257   adns__consistency(ads,0,cc_entex);
 258   return r;
 259 }
 260
 261 int adns_synchronous(adns_state ads,
 262                      const char *owner,
 263                      adns_rrtype type,
 264                      adns_queryflags flags,
 265                      adns_answer **answer_r) {
 266   adns_query qu;
 267   int r;
 268
 269   r= adns_submit(ads,owner,type,flags,0,&qu);
 270   if (r) return r;
 271
 272   r= adns_wait(ads,&qu,answer_r,0);
 273   if (r) adns_cancel(qu);
 274
 275   return r;
 276 }
 277
 278 static void *alloc_common(adns_query qu, size_t sz) {
 279   allocnode *an;
 280
 281   if (!sz) return qu; /* Any old pointer will do */
 282   assert(!qu->final_allocspace);
 283   an= malloc(MEM_ROUND(MEM_ROUND(sizeof(*an)) + sz));
 284   if (!an) return 0;
 285   LIST_LINK_TAIL(qu->allocations,an);
 286   return (byte*)an + MEM_ROUND(sizeof(*an));
 287 }
 288
 289 void *adns__alloc_interim(adns_query qu, size_t sz) {
 290   void *rv;
 291
 292   sz= MEM_ROUND(sz);
 293   rv= alloc_common(qu,sz);
 294   if (!rv) return 0;
 295   qu->interim_allocd += sz;
 296   return rv;
 297 }
 298
 299 void *adns__alloc_preserved(adns_query qu, size_t sz) {
 300   void *rv;
 301
 302   sz= MEM_ROUND(sz);
 303   rv= adns__alloc_interim(qu,sz);
 304   if (!rv) return 0;
 305   qu->preserved_allocd += sz;
 306   return rv;
 307 }
 308
 309 void *adns__alloc_mine(adns_query qu, size_t sz) {
 310   return alloc_common(qu,MEM_ROUND(sz));
 311 }
 312
 313 void adns__transfer_interim(adns_query from, adns_query to, void *block, size_t sz) {
 314   allocnode *an;
 315
 316   if (!block) return;
 317   an= (void*)((byte*)block - MEM_ROUND(sizeof(*an)));
 318
 319   assert(!to->final_allocspace);
 320   assert(!from->final_allocspace);
 321
 322   LIST_UNLINK(from->allocations,an);
 323   LIST_LINK_TAIL(to->allocations,an);
 324
 325   from->interim_allocd -= sz;
 326   to->interim_allocd += sz;
 327
 328   if (to->expires > from->expires) to->expires= from->expires;
 329 }
 330
 331 void *adns__alloc_final(adns_query qu, size_t sz) {
 332   /* When we're in the _final stage, we _subtract_ from interim_alloc'd
 333    * each allocation, and use final_allocspace to point to the next free
 334    * bit.
 335    */
 336   void *rp;
 337
 338   sz= MEM_ROUND(sz);
 339   rp= qu->final_allocspace;
 340   assert(rp);
 341   qu->interim_allocd -= sz;
 342   assert(qu->interim_allocd>=0);
 343   qu->final_allocspace= (byte*)rp + sz;
 344   return rp;
 345 }
 346
 347 static void cancel_children(adns_query qu) {
 348   adns_query cqu, ncqu;
 349
 350   for (cqu= qu->children.head; cqu; cqu= ncqu) {
 351     ncqu= cqu->siblings.next;
 352     adns_cancel(cqu);
 353   }
 354 }
 355
 356 void adns__reset_preserved(adns_query qu) {
 357   assert(!qu->final_allocspace);
 358   cancel_children(qu);
 359   qu->answer->nrrs= 0;
 360   qu->answer->rrs.untyped= 0;
 361   qu->interim_allocd= qu->preserved_allocd;
 362 }
 363
 364 static void free_query_allocs(adns_query qu) {
 365   allocnode *an, *ann;
 366
 367   cancel_children(qu);
 368   for (an= qu->allocations.head; an; an= ann) { ann= an->next; free(an); }
 369   LIST_INIT(qu->allocations);
 370   adns__vbuf_free(&qu->vb);
 371 }
 372
 373 void adns_cancel(adns_query qu) {
 374   adns_state ads;
 375
 376   ads= qu->ads;
 377   adns__consistency(ads,qu,cc_entex);
 378   if (qu->parent) LIST_UNLINK_PART(qu->parent->children,qu,siblings.);
 379   switch (qu->state) {
 380   case query_tosend: case query_tcpwait: case query_tcpsent:
 381     LIST_UNLINK(ads->timew,qu);
 382     break;
 383   case query_child:
 384     LIST_UNLINK(ads->childw,qu);
 385     break;
 386   case query_done:
 387     LIST_UNLINK(ads->output,qu);
 388     break;
 389   default:
 390     abort();
 391   }
 392   free_query_allocs(qu);
 393   free(qu->answer);
 394   free(qu);
 395   adns__consistency(ads,0,cc_entex);
 396 }
 397
 398 void adns__update_expires(adns_query qu, unsigned long ttl, struct timeval now) {
 399   time_t max;
 400
 401   assert(ttl <= MAXTTLBELIEVE);
 402   max= now.tv_sec + ttl;
 403   if (qu->expires < max) return;
 404   qu->expires= max;
 405 }
 406
 407 static void makefinal_query(adns_query qu) {
 408   adns_answer *ans;
 409   int rrn;
 410
 411   ans= qu->answer;
 412
 413   if (qu->interim_allocd) {
 414     ans= realloc(qu->answer, MEM_ROUND(MEM_ROUND(sizeof(*ans)) + qu->interim_allocd));
 415     if (!ans) goto x_nomem;
 416     qu->answer= ans;
 417   }
 418
 419   qu->final_allocspace= (byte*)ans + MEM_ROUND(sizeof(*ans));
 420   adns__makefinal_str(qu,&ans->cname);
 421   adns__makefinal_str(qu,&ans->owner);
 422
 423   if (ans->nrrs) {
 424     adns__makefinal_block(qu, &ans->rrs.untyped, ans->nrrs*ans->rrsz);
 425
 426     for (rrn=0; rrn<ans->nrrs; rrn++)
 427       qu->typei->makefinal(qu, ans->rrs.bytes + rrn*ans->rrsz);
 428   }
 429
 430   free_query_allocs(qu);
 431   return;
 432
 433  x_nomem:
 434   qu->preserved_allocd= 0;
 435   qu->answer->cname= 0;
 436   qu->answer->owner= 0;
 437   adns__reset_preserved(qu); /* (but we just threw away the preserved stuff) */
 438
 439   qu->answer->status= adns_s_nomemory;
 440   free_query_allocs(qu);
 441 }
 442
 443 void adns__query_done(adns_query qu) {
 444   adns_answer *ans;
 445   adns_query parent;
 446
 447   cancel_children(qu);
 448
 449   qu->id= -1;
 450   ans= qu->answer;
 451
 452   if (qu->flags & adns_qf_owner && qu->flags & adns_qf_search &&
 453       ans->status != adns_s_nomemory) {
 454     if (!save_owner(qu, qu->search_vb.buf, qu->search_vb.used)) {
 455       adns__query_fail(qu,adns_s_nomemory);
 456       return;
 457     }
 458   }
 459
 460   if (ans->nrrs && qu->typei->diff_needswap) {
 461     if (!adns__vbuf_ensure(&qu->vb,qu->typei->rrsz)) {
 462       adns__query_fail(qu,adns_s_nomemory);
 463       return;
 464     }
 465     adns__isort(ans->rrs.bytes, ans->nrrs, ans->rrsz,
 466                 qu->vb.buf,
 467                 (int(*)(void*, const void*, const void*))qu->typei->diff_needswap,
 468                 qu->ads);
 469   }
 470
 471   ans->expires= qu->expires;
 472   parent= qu->parent;
 473   if (parent) {
 474     LIST_UNLINK_PART(parent->children,qu,siblings.);
 475     LIST_UNLINK(qu->ads->childw,parent);
 476     qu->ctx.callback(parent,qu);
 477     free_query_allocs(qu);
 478     free(qu);
 479   } else {
 480     makefinal_query(qu);
 481     LIST_LINK_TAIL(qu->ads->output,qu);
 482     qu->state= query_done;
 483   }
 484 }
 485
 486 void adns__query_fail(adns_query qu, adns_status stat) {
 487   adns__reset_preserved(qu);
 488   qu->answer->status= stat;
 489   adns__query_done(qu);
 490 }
 491
 492 void adns__makefinal_str(adns_query qu, char **strp) {
 493   int l;
 494   char *before, *after;
 495
 496   before= *strp;
 497   if (!before) return;
 498   l= strlen(before)+1;
 499   after= adns__alloc_final(qu,l);
 500   memcpy(after,before,l);
 501   *strp= after;
 502 }
 503
 504 void adns__makefinal_block(adns_query qu, void **blpp, size_t sz) {
 505   void *before, *after;
 506
 507   before= *blpp;
 508   if (!before) return;
 509   after= adns__alloc_final(qu,sz);
 510   memcpy(after,before,sz);
 511   *blpp= after;
 512 }