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
   9  *    Copyright (C) 1997-2000,2003,2006  Ian Jackson
  10  *    Copyright (C) 1999-2000,2003,2006  Tony Finch
  11  *    Copyright (C) 1991 Massachusetts Institute of Technology
  12  *  (See the file INSTALL for full details.)
  13  *
  14  *  This program is free software; you can redistribute it and/or modify
  15  *  it under the terms of the GNU General Public License as published by
  16  *  the Free Software Foundation; either version 2, or (at your option)
  17  *  any later version.
  18  *
  19  *  This program is distributed in the hope that it will be useful,
  20  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  *  GNU General Public License for more details.
  23  *
  24  *  You should have received a copy of the GNU General Public License
  25  *  along with this program; if not, write to the Free Software Foundation,
  26  *  Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  27  */
  28
  29 #include "internal.h"
  30
  31 #include <stdlib.h>
  32 #include <unistd.h>
  33 #include <errno.h>
  34
  35 #include <sys/time.h>
  36
  37 #include "internal.h"
  38
  39 static adns_query query_alloc(adns_state ads,
  40                               const typeinfo *typei, adns_rrtype type,
  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));
  47   if (!qu->answer) { free(qu); return 0; }
  48
  49   qu->ads= ads;
  50   qu->state= query_tosend;
  51   qu->back= qu->next= qu->parent= 0;
  52   LIST_INIT(qu->children);
  53   LINK_INIT(qu->siblings);
  54   LIST_INIT(qu->allocations);
  55   qu->interim_allocd= 0;
  56   qu->preserved_allocd= 0;
  57   qu->final_allocspace= 0;
  58
  59   qu->typei= typei;
  60   qu->query_dgram= 0;
  61   qu->query_dglen= 0;
  62   adns__vbuf_init(&qu->vb);
  63
  64   qu->cname_dgram= 0;
  65   qu->cname_dglen= qu->cname_begin= 0;
  66
  67   adns__vbuf_init(&qu->search_vb);
  68   qu->search_origlen= qu->search_pos= qu->search_doneabs= 0;
  69
  70   qu->id= -2; /* will be overwritten with real id before we leave adns */
  71   qu->flags= flags;
  72   qu->retries= 0;
  73   qu->udpnextserver= 0;
  74   qu->udpsent= 0;
  75   timerclear(&qu->timeout);
  76   qu->expires= now.tv_sec + MAXTTLBELIEVE;
  77
  78   memset(&qu->ctx,0,sizeof(qu->ctx));
  79
  80   qu->answer->status= adns_s_ok;
  81   qu->answer->cname= qu->answer->owner= 0;
  82   qu->answer->type= type;
  83   qu->answer->expires= -1;
  84   qu->answer->nrrs= 0;
  85   qu->answer->rrs.untyped= 0;
  86   qu->answer->rrsz= typei->rrsz;
  87
  88   return qu;
  89 }
  90
  91 static void query_submit(adns_state ads, adns_query qu,
  92                          const typeinfo *typei, vbuf *qumsg_vb, int id,
  93                          adns_queryflags flags, struct timeval now) {
  94   /* Fills in the query message in for a previously-allocated query,
  95    * and submits it.  Cannot fail.  Takes over the memory for qumsg_vb.
  96    */
  97
  98   qu->vb= *qumsg_vb;
  99   adns__vbuf_init(qumsg_vb);
 100
 101   qu->query_dgram= malloc(qu->vb.used);
 102   if (!qu->query_dgram) { adns__query_fail(qu,adns_s_nomemory); return; }
 103
 104   qu->id= id;
 105   qu->query_dglen= qu->vb.used;
 106   memcpy(qu->query_dgram,qu->vb.buf,qu->vb.used);
 107
 108   adns__query_send(qu,now);
 109 }
 110
 111 adns_status adns__internal_submit(adns_state ads, adns_query *query_r,
 112                                   const typeinfo *typei, vbuf *qumsg_vb,
 113                                   int id,
 114                                   adns_queryflags flags, struct timeval now,
 115                                   const qcontext *ctx) {
 116   adns_query qu;
 117
 118   qu= query_alloc(ads,typei,typei->typekey,flags,now);
 119   if (!qu) { adns__vbuf_free(qumsg_vb); return adns_s_nomemory; }
 120   *query_r= qu;
 121
 122   memcpy(&qu->ctx,ctx,sizeof(qu->ctx));
 123   query_submit(ads,qu, typei,qumsg_vb,id,flags,now);
 124
 125   return adns_s_ok;
 126 }
 127
 128 static void query_simple(adns_state ads, adns_query qu,
 129                          const char *owner, int ol,
 130                          const typeinfo *typei, adns_queryflags flags,
 131                          struct timeval now) {
 132   vbuf vb_new;
 133   int id;
 134   adns_status stat;
 135
 136   stat= adns__mkquery(ads,&qu->vb,&id, owner,ol,
 137                       typei,qu->answer->type, flags);
 138   if (stat) {
 139     if (stat == adns_s_querydomaintoolong && (flags & adns_qf_search)) {
 140       adns__search_next(ads,qu,now);
 141       return;
 142     } else {
 143       adns__query_fail(qu,stat);
 144       return;
 145     }
 146   }
 147
 148   vb_new= qu->vb;
 149   adns__vbuf_init(&qu->vb);
 150   query_submit(ads,qu, typei,&vb_new,id, flags,now);
 151 }
 152
 153 void adns__search_next(adns_state ads, adns_query qu, struct timeval now) {
 154   const char *nextentry;
 155   adns_status stat;
 156
 157   if (qu->search_doneabs<0) {
 158     nextentry= 0;
 159     qu->search_doneabs= 1;
 160   } else {
 161     if (qu->search_pos >= ads->nsearchlist) {
 162       if (qu->search_doneabs) {
 163         qu->search_vb.used= qu->search_origlen;
 164         stat= adns_s_nxdomain; goto x_fail;
 165       } else {
 166         nextentry= 0;
 167         qu->search_doneabs= 1;
 168       }
 169     } else {
 170       nextentry= ads->searchlist[qu->search_pos++];
 171     }
 172   }
 173
 174   qu->search_vb.used= qu->search_origlen;
 175   if (nextentry) {
 176     if (!adns__vbuf_append(&qu->search_vb,".",1) ||
 177         !adns__vbuf_appendstr(&qu->search_vb,nextentry))
 178       goto x_nomemory;
 179   }
 180
 181   free(qu->query_dgram);
 182   qu->query_dgram= 0; qu->query_dglen= 0;
 183
 184   query_simple(ads,qu, qu->search_vb.buf, qu->search_vb.used,
 185                qu->typei, qu->flags, now);
 186   return;
 187
 188 x_nomemory:
 189   stat= adns_s_nomemory;
 190 x_fail:
 191   adns__query_fail(qu,stat);
 192 }
 193
 194 static int save_owner(adns_query qu, const char *owner, int ol) {
 195   /* Returns 1 if OK, otherwise there was no memory. */
 196   adns_answer *ans;
 197
 198   if (!(qu->flags & adns_qf_owner)) return 1;
 199
 200   ans= qu->answer;
 201   assert(!ans->owner);
 202
 203   ans->owner= adns__alloc_preserved(qu,ol+1);  if (!ans->owner) return 0;
 204
 205   memcpy(ans->owner,owner,ol);
 206   ans->owner[ol]= 0;
 207   return 1;
 208 }
 209
 210 int adns_submit(adns_state ads,
 211                 const char *owner,
 212                 adns_rrtype type,
 213                 adns_queryflags flags,
 214                 void *context,
 215                 adns_query *query_r) {
 216   int r, ol, ndots;
 217   adns_status stat;
 218   const typeinfo *typei;
 219   struct timeval now;
 220   adns_query qu;
 221   const char *p;
 222
 223   adns__consistency(ads,0,cc_entex);
 224
 225   typei= adns__findtype(type);
 226   if (!typei) return ENOSYS;
 227
 228   r= gettimeofday(&now,0); if (r) goto x_errno;
 229   qu= query_alloc(ads,typei,type,flags,now); if (!qu) goto x_errno;
 230
 231   qu->ctx.ext= context;
 232   qu->ctx.callback= 0;
 233   memset(&qu->ctx.info,0,sizeof(qu->ctx.info));
 234
 235   *query_r= qu;
 236
 237   ol= strlen(owner);
 238   if (!ol) { stat= adns_s_querydomaininvalid; goto x_adnsfail; }
 239   if (ol>DNS_MAXDOMAIN+1) { stat= adns_s_querydomaintoolong; goto x_adnsfail; }
 240
 241   if (ol>=1 && owner[ol-1]=='.' && (ol<2 || owner[ol-2]!='\\')) {
 242     flags &= ~adns_qf_search;
 243     qu->flags= flags;
 244     ol--;
 245   }
 246
 247   if (flags & adns_qf_search) {
 248     r= adns__vbuf_append(&qu->search_vb,owner,ol);
 249     if (!r) { stat= adns_s_nomemory; goto x_adnsfail; }
 250
 251     for (ndots=0, p=owner; (p= strchr(p,'.')); p++, ndots++);
 252     qu->search_doneabs= (ndots >= ads->searchndots) ? -1 : 0;
 253     qu->search_origlen= ol;
 254     adns__search_next(ads,qu,now);
 255   } else {
 256     if (flags & adns_qf_owner) {
 257       if (!save_owner(qu,owner,ol)) { stat= adns_s_nomemory; goto x_adnsfail; }
 258     }
 259     query_simple(ads,qu, owner,ol, typei,flags, now);
 260   }
 261   adns__autosys(ads,now);
 262   adns__consistency(ads,qu,cc_entex);
 263   return 0;
 264
 265  x_adnsfail:
 266   adns__query_fail(qu,stat);
 267   adns__consistency(ads,qu,cc_entex);
 268   return 0;
 269
 270  x_errno:
 271   r= errno;
 272   assert(r);
 273   adns__consistency(ads,0,cc_entex);
 274   return r;
 275 }
 276
 277 static const char *default_zone = "<magic>";
 278
 279 int adns_submit_reverse_any(adns_state ads,
 280                             const struct sockaddr *addr,
 281                             const char *zone,
 282                             adns_rrtype type,
 283                             adns_queryflags flags,
 284                             void *context,
 285                             adns_query *query_r) {
 286   char *buf, *buf_free, *p;
 287   char shortbuf[100];
 288   const afinfo *ai;
 289   int r, lreq;
 290
 291   flags &= ~adns_qf_search;
 292
 293   switch (addr->sa_family) {
 294     case AF_INET:
 295       ai = &adns__inet_afinfo;
 296       if (zone == default_zone) zone = "in-addr.arpa";
 297       break;
 298     case AF_INET6:
 299       ai = &adns__inet6_afinfo;
 300       if (zone == default_zone) zone = "ip6.arpa";
 301       break;
 302     default:
 303       return ENOSYS;
 304   }
 305
 306   lreq= strlen(zone) + ai->nrevcomp*(ai->revcompwd + 1) + 1;
 307   if (lreq > sizeof(shortbuf)) {
 308     buf= malloc(lreq);
 309     if (!buf) return errno;
 310     buf_free= buf;
 311   } else {
 312     buf= shortbuf;
 313     buf_free= 0;
 314   }
 315
 316   p = ai->rev_mkname(addr, buf);
 317   *p++ = '.';
 318   strcpy(p, zone);
 319
 320   r= adns_submit(ads,buf,type,flags,context,query_r);
 321   free(buf_free);
 322   return r;
 323 }
 324
 325 int adns_submit_reverse(adns_state ads,
 326                         const struct sockaddr *addr,
 327                         adns_rrtype type,
 328                         adns_queryflags flags,
 329                         void *context,
 330                         adns_query *query_r) {
 331   if (type != adns_r_ptr && type != adns_r_ptr_raw) return EINVAL;
 332   return adns_submit_reverse_any(ads,addr,default_zone,
 333                                  type,flags,context,query_r);
 334 }
 335
 336 int adns_synchronous(adns_state ads,
 337                      const char *owner,
 338                      adns_rrtype type,
 339                      adns_queryflags flags,
 340                      adns_answer **answer_r) {
 341   adns_query qu;
 342   int r;
 343
 344   r= adns_submit(ads,owner,type,flags,0,&qu);
 345   if (r) return r;
 346
 347   r= adns_wait(ads,&qu,answer_r,0);
 348   if (r) adns_cancel(qu);
 349
 350   return r;
 351 }
 352
 353 static void *alloc_common(adns_query qu, size_t sz) {
 354   allocnode *an;
 355
 356   if (!sz) return qu; /* Any old pointer will do */
 357   assert(!qu->final_allocspace);
 358   an= malloc(MEM_ROUND(MEM_ROUND(sizeof(*an)) + sz));
 359   if (!an) return 0;
 360   LIST_LINK_TAIL(qu->allocations,an);
 361   return (byte*)an + MEM_ROUND(sizeof(*an));
 362 }
 363
 364 void *adns__alloc_interim(adns_query qu, size_t sz) {
 365   void *rv;
 366
 367   sz= MEM_ROUND(sz);
 368   rv= alloc_common(qu,sz);
 369   if (!rv) return 0;
 370   qu->interim_allocd += sz;
 371   return rv;
 372 }
 373
 374 void *adns__alloc_preserved(adns_query qu, size_t sz) {
 375   void *rv;
 376
 377   sz= MEM_ROUND(sz);
 378   rv= adns__alloc_interim(qu,sz);
 379   if (!rv) return 0;
 380   qu->preserved_allocd += sz;
 381   return rv;
 382 }
 383
 384 void *adns__alloc_mine(adns_query qu, size_t sz) {
 385   return alloc_common(qu,MEM_ROUND(sz));
 386 }
 387
 388 void adns__transfer_interim(adns_query from, adns_query to,
 389                             void *block, size_t sz) {
 390   allocnode *an;
 391
 392   if (!block) return;
 393   an= (void*)((byte*)block - MEM_ROUND(sizeof(*an)));
 394
 395   assert(!to->final_allocspace);
 396   assert(!from->final_allocspace);
 397
 398   LIST_UNLINK(from->allocations,an);
 399   LIST_LINK_TAIL(to->allocations,an);
 400
 401   sz= MEM_ROUND(sz);
 402   from->interim_allocd -= sz;
 403   to->interim_allocd += sz;
 404
 405   if (to->expires > from->expires) to->expires= from->expires;
 406 }
 407
 408 void *adns__alloc_final(adns_query qu, size_t sz) {
 409   /* When we're in the _final stage, we _subtract_ from interim_alloc'd
 410    * each allocation, and use final_allocspace to point to the next free
 411    * bit.
 412    */
 413   void *rp;
 414
 415   sz= MEM_ROUND(sz);
 416   rp= qu->final_allocspace;
 417   assert(rp);
 418   qu->interim_allocd -= sz;
 419   assert(qu->interim_allocd>=0);
 420   qu->final_allocspace= (byte*)rp + sz;
 421   return rp;
 422 }
 423
 424 static void cancel_children(adns_query qu) {
 425   adns_query cqu, ncqu;
 426
 427   for (cqu= qu->children.head; cqu; cqu= ncqu) {
 428     ncqu= cqu->siblings.next;
 429     adns_cancel(cqu);
 430   }
 431 }
 432
 433 void adns__reset_preserved(adns_query qu) {
 434   assert(!qu->final_allocspace);
 435   cancel_children(qu);
 436   qu->answer->nrrs= 0;
 437   qu->answer->rrs.untyped= 0;
 438   qu->interim_allocd= qu->preserved_allocd;
 439 }
 440
 441 static void free_query_allocs(adns_query qu) {
 442   allocnode *an, *ann;
 443
 444   cancel_children(qu);
 445   for (an= qu->allocations.head; an; an= ann) { ann= an->next; free(an); }
 446   LIST_INIT(qu->allocations);
 447   adns__vbuf_free(&qu->vb);
 448   adns__vbuf_free(&qu->search_vb);
 449   free(qu->query_dgram);
 450   qu->query_dgram= 0;
 451 }
 452
 453 void adns_cancel(adns_query qu) {
 454   adns_state ads;
 455
 456   ads= qu->ads;
 457   adns__consistency(ads,qu,cc_entex);
 458   if (qu->parent) LIST_UNLINK_PART(qu->parent->children,qu,siblings.);
 459   switch (qu->state) {
 460   case query_tosend:
 461     LIST_UNLINK(ads->udpw,qu);
 462     break;
 463   case query_tcpw:
 464     LIST_UNLINK(ads->tcpw,qu);
 465     break;
 466   case query_childw:
 467     LIST_UNLINK(ads->childw,qu);
 468     break;
 469   case query_done:
 470     LIST_UNLINK(ads->output,qu);
 471     break;
 472   default:
 473     abort();
 474   }
 475   free_query_allocs(qu);
 476   free(qu->answer);
 477   free(qu);
 478   adns__consistency(ads,0,cc_entex);
 479 }
 480
 481 void adns__update_expires(adns_query qu, unsigned long ttl,
 482                           struct timeval now) {
 483   time_t max;
 484
 485   assert(ttl <= MAXTTLBELIEVE);
 486   max= now.tv_sec + ttl;
 487   if (qu->expires < max) return;
 488   qu->expires= max;
 489 }
 490
 491 static void makefinal_query(adns_query qu) {
 492   adns_answer *ans;
 493   int rrn;
 494
 495   ans= qu->answer;
 496
 497   if (qu->interim_allocd) {
 498     ans= realloc(qu->answer,
 499                  MEM_ROUND(MEM_ROUND(sizeof(*ans)) + qu->interim_allocd));
 500     if (!ans) goto x_nomem;
 501     qu->answer= ans;
 502   }
 503
 504   qu->final_allocspace= (byte*)ans + MEM_ROUND(sizeof(*ans));
 505   adns__makefinal_str(qu,&ans->cname);
 506   adns__makefinal_str(qu,&ans->owner);
 507
 508   if (ans->nrrs) {
 509     adns__makefinal_block(qu, &ans->rrs.untyped, ans->nrrs*ans->rrsz);
 510
 511     for (rrn=0; rrn<ans->nrrs; rrn++)
 512       qu->typei->makefinal(qu, ans->rrs.bytes + rrn*ans->rrsz);
 513   }
 514
 515   free_query_allocs(qu);
 516   return;
 517
 518  x_nomem:
 519   qu->preserved_allocd= 0;
 520   qu->answer->cname= 0;
 521   qu->answer->owner= 0;
 522   adns__reset_preserved(qu); /* (but we just threw away the preserved stuff) */
 523
 524   qu->answer->status= adns_s_nomemory;
 525   free_query_allocs(qu);
 526 }
 527
 528 void adns__query_done(adns_query qu) {
 529   adns_answer *ans;
 530   adns_query parent;
 531
 532   cancel_children(qu);
 533
 534   qu->id= -1;
 535   ans= qu->answer;
 536
 537   if (qu->flags & adns_qf_search && ans->status != adns_s_nomemory) {
 538     if (!save_owner(qu, qu->search_vb.buf, qu->search_vb.used)) {
 539       adns__query_fail(qu,adns_s_nomemory);
 540       return;
 541     }
 542   }
 543
 544   if (ans->nrrs && qu->typei->diff_needswap) {
 545     if (!adns__vbuf_ensure(&qu->vb,qu->typei->rrsz)) {
 546       adns__query_fail(qu,adns_s_nomemory);
 547       return;
 548     }
 549     adns__isort(ans->rrs.bytes, ans->nrrs, ans->rrsz,
 550                 qu->vb.buf,
 551                 (int(*)(void*, const void*, const void*))
 552                   qu->typei->diff_needswap,
 553                 qu->ads);
 554   }
 555   if (ans->nrrs && qu->typei->postsort) {
 556     qu->typei->postsort(qu->ads, ans->rrs.bytes, ans->nrrs, qu->typei);
 557   }
 558
 559   ans->expires= qu->expires;
 560   parent= qu->parent;
 561   if (parent) {
 562     LIST_UNLINK_PART(parent->children,qu,siblings.);
 563     LIST_UNLINK(qu->ads->childw,parent);
 564     qu->ctx.callback(parent,qu);
 565     free_query_allocs(qu);
 566     free(qu->answer);
 567     free(qu);
 568   } else {
 569     makefinal_query(qu);
 570     LIST_LINK_TAIL(qu->ads->output,qu);
 571     qu->state= query_done;
 572   }
 573 }
 574
 575 void adns__query_fail(adns_query qu, adns_status stat) {
 576   adns__reset_preserved(qu);
 577   qu->answer->status= stat;
 578   adns__query_done(qu);
 579 }
 580
 581 void adns__makefinal_str(adns_query qu, char **strp) {
 582   int l;
 583   char *before, *after;
 584
 585   before= *strp;
 586   if (!before) return;
 587   l= strlen(before)+1;
 588   after= adns__alloc_final(qu,l);
 589   memcpy(after,before,l);
 590   *strp= after;
 591 }
 592
 593 void adns__makefinal_block(adns_query qu, void **blpp, size_t sz) {
 594   void *before, *after;
 595
 596   before= *blpp;
 597   if (!before) return;
 598   after= adns__alloc_final(qu,sz);
 599   memcpy(after,before,sz);
 600   *blpp= after;
 601 }