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->getrrsz ? typei->getrrsz(type) : 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   if (typei->query_send) typei->query_send(qu,now);
 109   else adns__query_send(qu, now);
 110 }
 111
 112 adns_status adns__internal_submit(adns_state ads, adns_query *query_r,
 113                                   const typeinfo *typei, adns_rrtype type,
 114                                   vbuf *qumsg_vb, int id,
 115                                   adns_queryflags flags, struct timeval now,
 116                                   const qcontext *ctx) {
 117   adns_query qu;
 118
 119   qu= query_alloc(ads,typei,type,flags,now);
 120   if (!qu) { adns__vbuf_free(qumsg_vb); return adns_s_nomemory; }
 121   *query_r= qu;
 122
 123   memcpy(&qu->ctx,ctx,sizeof(qu->ctx));
 124   query_submit(ads,qu, typei,qumsg_vb,id,flags,now);
 125
 126   return adns_s_ok;
 127 }
 128
 129 static void query_simple(adns_state ads, adns_query qu,
 130                          const char *owner, int ol,
 131                          const typeinfo *typei, adns_queryflags flags,
 132                          struct timeval now) {
 133   vbuf vb_new;
 134   int id;
 135   adns_status stat;
 136
 137   stat= adns__mkquery(ads,&qu->vb,&id, owner,ol,
 138                       typei,qu->answer->type, flags);
 139   if (stat) {
 140     if (stat == adns_s_querydomaintoolong && (flags & adns_qf_search)) {
 141       adns__search_next(ads,qu,now);
 142       return;
 143     } else {
 144       adns__query_fail(qu,stat);
 145       return;
 146     }
 147   }
 148
 149   vb_new= qu->vb;
 150   adns__vbuf_init(&qu->vb);
 151   query_submit(ads,qu, typei,&vb_new,id, flags,now);
 152 }
 153
 154 void adns__search_next(adns_state ads, adns_query qu, struct timeval now) {
 155   const char *nextentry;
 156   adns_status stat;
 157
 158   if (qu->search_doneabs<0) {
 159     nextentry= 0;
 160     qu->search_doneabs= 1;
 161   } else {
 162     if (qu->search_pos >= ads->nsearchlist) {
 163       if (qu->search_doneabs) {
 164         qu->search_vb.used= qu->search_origlen;
 165         stat= adns_s_nxdomain; goto x_fail;
 166       } else {
 167         nextentry= 0;
 168         qu->search_doneabs= 1;
 169       }
 170     } else {
 171       nextentry= ads->searchlist[qu->search_pos++];
 172     }
 173   }
 174
 175   qu->search_vb.used= qu->search_origlen;
 176   if (nextentry) {
 177     if (!adns__vbuf_append(&qu->search_vb,".",1) ||
 178         !adns__vbuf_appendstr(&qu->search_vb,nextentry))
 179       goto x_nomemory;
 180   }
 181
 182   free(qu->query_dgram);
 183   qu->query_dgram= 0; qu->query_dglen= 0;
 184
 185   query_simple(ads,qu, qu->search_vb.buf, qu->search_vb.used,
 186                qu->typei, qu->flags, now);
 187   return;
 188
 189 x_nomemory:
 190   stat= adns_s_nomemory;
 191 x_fail:
 192   adns__query_fail(qu,stat);
 193 }
 194
 195 static int save_owner(adns_query qu, const char *owner, int ol) {
 196   /* Returns 1 if OK, otherwise there was no memory. */
 197   adns_answer *ans;
 198
 199   if (!(qu->flags & adns_qf_owner)) return 1;
 200
 201   ans= qu->answer;
 202   assert(!ans->owner);
 203
 204   ans->owner= adns__alloc_preserved(qu,ol+1);  if (!ans->owner) return 0;
 205
 206   memcpy(ans->owner,owner,ol);
 207   ans->owner[ol]= 0;
 208   return 1;
 209 }
 210
 211 int adns_submit(adns_state ads,
 212                 const char *owner,
 213                 adns_rrtype type,
 214                 adns_queryflags flags,
 215                 void *context,
 216                 adns_query *query_r) {
 217   int r, ol, ndots;
 218   adns_status stat;
 219   const typeinfo *typei;
 220   struct timeval now;
 221   adns_query qu;
 222   const char *p;
 223
 224   adns__consistency(ads,0,cc_entex);
 225
 226   typei= adns__findtype(type);
 227   if (!typei) return ENOSYS;
 228
 229   r= gettimeofday(&now,0); if (r) goto x_errno;
 230   qu= query_alloc(ads,typei,type,flags,now); if (!qu) goto x_errno;
 231
 232   qu->ctx.ext= context;
 233   qu->ctx.callback= 0;
 234   memset(&qu->ctx.pinfo,0,sizeof(qu->ctx.pinfo));
 235   memset(&qu->ctx.tinfo,0,sizeof(qu->ctx.tinfo));
 236
 237   *query_r= qu;
 238
 239   ol= strlen(owner);
 240   if (!ol) { stat= adns_s_querydomaininvalid; goto x_adnsfail; }
 241   if (ol>DNS_MAXDOMAIN+1) { stat= adns_s_querydomaintoolong; goto x_adnsfail; }
 242
 243   if (ol>=1 && owner[ol-1]=='.' && (ol<2 || owner[ol-2]!='\\')) {
 244     flags &= ~adns_qf_search;
 245     qu->flags= flags;
 246     ol--;
 247   }
 248
 249   if (flags & adns_qf_search) {
 250     r= adns__vbuf_append(&qu->search_vb,owner,ol);
 251     if (!r) { stat= adns_s_nomemory; goto x_adnsfail; }
 252
 253     for (ndots=0, p=owner; (p= strchr(p,'.')); p++, ndots++);
 254     qu->search_doneabs= (ndots >= ads->searchndots) ? -1 : 0;
 255     qu->search_origlen= ol;
 256     adns__search_next(ads,qu,now);
 257   } else {
 258     if (flags & adns_qf_owner) {
 259       if (!save_owner(qu,owner,ol)) { stat= adns_s_nomemory; goto x_adnsfail; }
 260     }
 261     query_simple(ads,qu, owner,ol, typei,flags, now);
 262   }
 263   adns__autosys(ads,now);
 264   adns__consistency(ads,qu,cc_entex);
 265   return 0;
 266
 267  x_adnsfail:
 268   adns__query_fail(qu,stat);
 269   adns__consistency(ads,qu,cc_entex);
 270   return 0;
 271
 272  x_errno:
 273   r= errno;
 274   assert(r);
 275   adns__consistency(ads,0,cc_entex);
 276   return r;
 277 }
 278
 279 static const char *default_zone = "<magic>";
 280
 281 int adns_submit_reverse_any(adns_state ads,
 282                             const struct sockaddr *addr,
 283                             const char *zone,
 284                             adns_rrtype type,
 285                             adns_queryflags flags,
 286                             void *context,
 287                             adns_query *query_r) {
 288   char *buf, *buf_free, *p;
 289   char shortbuf[100];
 290   const afinfo *ai;
 291   int r, lreq;
 292
 293   flags &= ~adns_qf_search;
 294
 295   switch (addr->sa_family) {
 296     case AF_INET:
 297       ai = &adns__inet_afinfo;
 298       if (zone == default_zone) zone = "in-addr.arpa";
 299       break;
 300     case AF_INET6:
 301       ai = &adns__inet6_afinfo;
 302       if (zone == default_zone) zone = "ip6.arpa";
 303       break;
 304     default:
 305       return ENOSYS;
 306   }
 307
 308   lreq= strlen(zone) + ai->nrevcomp*(ai->revcompwd + 1) + 1;
 309   if (lreq > sizeof(shortbuf)) {
 310     buf= malloc(lreq);
 311     if (!buf) return errno;
 312     buf_free= buf;
 313   } else {
 314     buf= shortbuf;
 315     buf_free= 0;
 316   }
 317
 318   p = ai->rev_mkname(addr, buf);
 319   *p++ = '.';
 320   strcpy(p, zone);
 321
 322   r= adns_submit(ads,buf,type,flags,context,query_r);
 323   free(buf_free);
 324   return r;
 325 }
 326
 327 int adns_submit_reverse(adns_state ads,
 328                         const struct sockaddr *addr,
 329                         adns_rrtype type,
 330                         adns_queryflags flags,
 331                         void *context,
 332                         adns_query *query_r) {
 333   if (type != adns_r_ptr && type != adns_r_ptr_raw) return EINVAL;
 334   return adns_submit_reverse_any(ads,addr,default_zone,
 335                                  type,flags,context,query_r);
 336 }
 337
 338 int adns_synchronous(adns_state ads,
 339                      const char *owner,
 340                      adns_rrtype type,
 341                      adns_queryflags flags,
 342                      adns_answer **answer_r) {
 343   adns_query qu;
 344   int r;
 345
 346   r= adns_submit(ads,owner,type,flags,0,&qu);
 347   if (r) return r;
 348
 349   r= adns_wait(ads,&qu,answer_r,0);
 350   if (r) adns_cancel(qu);
 351
 352   return r;
 353 }
 354
 355 static void *alloc_common(adns_query qu, size_t sz) {
 356   allocnode *an;
 357
 358   if (!sz) return qu; /* Any old pointer will do */
 359   assert(!qu->final_allocspace);
 360   an= malloc(MEM_ROUND(MEM_ROUND(sizeof(*an)) + sz));
 361   if (!an) return 0;
 362   LIST_LINK_TAIL(qu->allocations,an);
 363   an->sz = sz;
 364   return (byte*)an + MEM_ROUND(sizeof(*an));
 365 }
 366
 367 void *adns__alloc_interim(adns_query qu, size_t sz) {
 368   void *rv;
 369
 370   sz= MEM_ROUND(sz);
 371   rv= alloc_common(qu,sz);
 372   if (!rv) return 0;
 373   qu->interim_allocd += sz;
 374   return rv;
 375 }
 376
 377 void *adns__alloc_preserved(adns_query qu, size_t sz) {
 378   void *rv;
 379
 380   sz= MEM_ROUND(sz);
 381   rv= adns__alloc_interim(qu,sz);
 382   if (!rv) return 0;
 383   qu->preserved_allocd += sz;
 384   return rv;
 385 }
 386
 387 static allocnode *alloc_info(adns_query qu, void *p, size_t *sz_r)
 388 {
 389   allocnode *an;
 390
 391   if (!p || p == qu) { *sz_r = 0; return 0; }
 392   an = (allocnode *)((byte *)p - MEM_ROUND(sizeof(allocnode)));
 393   *sz_r = MEM_ROUND(an->sz);
 394   return an;
 395 }
 396
 397 void adns__free_interim(adns_query qu, void *p) {
 398   size_t sz;
 399   allocnode *an = alloc_info(qu, p, &sz);
 400
 401   if (!an) return;
 402   assert(!qu->final_allocspace);
 403   LIST_UNLINK(qu->allocations, an);
 404   free(an);
 405   qu->interim_allocd -= sz;
 406 }
 407
 408 void *adns__alloc_mine(adns_query qu, size_t sz) {
 409   return alloc_common(qu,MEM_ROUND(sz));
 410 }
 411
 412 void adns__transfer_interim(adns_query from, adns_query to, void *block) {
 413   size_t sz;
 414   allocnode *an = alloc_info(from, block, &sz);
 415
 416   if (!an) return;
 417
 418   assert(!to->final_allocspace);
 419   assert(!from->final_allocspace);
 420
 421   LIST_UNLINK(from->allocations,an);
 422   LIST_LINK_TAIL(to->allocations,an);
 423
 424   from->interim_allocd -= sz;
 425   to->interim_allocd += sz;
 426
 427   if (to->expires > from->expires) to->expires= from->expires;
 428 }
 429
 430 void *adns__alloc_final(adns_query qu, size_t sz) {
 431   /* When we're in the _final stage, we _subtract_ from interim_alloc'd
 432    * each allocation, and use final_allocspace to point to the next free
 433    * bit.
 434    */
 435   void *rp;
 436
 437   sz= MEM_ROUND(sz);
 438   rp= qu->final_allocspace;
 439   assert(rp);
 440   qu->interim_allocd -= sz;
 441   assert(qu->interim_allocd>=0);
 442   qu->final_allocspace= (byte*)rp + sz;
 443   return rp;
 444 }
 445
 446 void adns__cancel_children(adns_query qu) {
 447   adns_query cqu, ncqu;
 448
 449   for (cqu= qu->children.head; cqu; cqu= ncqu) {
 450     ncqu= cqu->siblings.next;
 451     adns_cancel(cqu);
 452   }
 453 }
 454
 455 void adns__reset_preserved(adns_query qu) {
 456   assert(!qu->final_allocspace);
 457   adns__cancel_children(qu);
 458   qu->answer->nrrs= 0;
 459   qu->answer->rrs.untyped= 0;
 460   qu->interim_allocd= qu->preserved_allocd;
 461 }
 462
 463 static void free_query_allocs(adns_query qu) {
 464   allocnode *an, *ann;
 465
 466   adns__cancel_children(qu);
 467   for (an= qu->allocations.head; an; an= ann) { ann= an->next; free(an); }
 468   LIST_INIT(qu->allocations);
 469   adns__vbuf_free(&qu->vb);
 470   adns__vbuf_free(&qu->search_vb);
 471   free(qu->query_dgram);
 472   qu->query_dgram= 0;
 473 }
 474
 475 void adns_cancel(adns_query qu) {
 476   adns_state ads;
 477
 478   ads= qu->ads;
 479   adns__consistency(ads,qu,cc_entex);
 480   if (qu->parent) LIST_UNLINK_PART(qu->parent->children,qu,siblings.);
 481   switch (qu->state) {
 482   case query_tosend:
 483     LIST_UNLINK(ads->udpw,qu);
 484     break;
 485   case query_tcpw:
 486     LIST_UNLINK(ads->tcpw,qu);
 487     break;
 488   case query_childw:
 489     LIST_UNLINK(ads->childw,qu);
 490     break;
 491   case query_done:
 492     LIST_UNLINK(ads->output,qu);
 493     break;
 494   default:
 495     abort();
 496   }
 497   free_query_allocs(qu);
 498   free(qu->answer);
 499   free(qu);
 500   adns__consistency(ads,0,cc_entex);
 501 }
 502
 503 void adns__update_expires(adns_query qu, unsigned long ttl,
 504                           struct timeval now) {
 505   time_t max;
 506
 507   assert(ttl <= MAXTTLBELIEVE);
 508   max= now.tv_sec + ttl;
 509   if (qu->expires < max) return;
 510   qu->expires= max;
 511 }
 512
 513 static void makefinal_query(adns_query qu) {
 514   adns_answer *ans;
 515   int rrn;
 516
 517   ans= qu->answer;
 518
 519   if (qu->interim_allocd) {
 520     ans= realloc(qu->answer,
 521                  MEM_ROUND(MEM_ROUND(sizeof(*ans)) + qu->interim_allocd));
 522     if (!ans) goto x_nomem;
 523     qu->answer= ans;
 524   }
 525
 526   qu->final_allocspace= (byte*)ans + MEM_ROUND(sizeof(*ans));
 527   adns__makefinal_str(qu,&ans->cname);
 528   adns__makefinal_str(qu,&ans->owner);
 529
 530   if (ans->nrrs) {
 531     adns__makefinal_block(qu, &ans->rrs.untyped, ans->nrrs*ans->rrsz);
 532
 533     for (rrn=0; rrn<ans->nrrs; rrn++)
 534       qu->typei->makefinal(qu, ans->rrs.bytes + rrn*ans->rrsz);
 535   }
 536
 537   free_query_allocs(qu);
 538   return;
 539
 540  x_nomem:
 541   qu->preserved_allocd= 0;
 542   qu->answer->cname= 0;
 543   qu->answer->owner= 0;
 544   adns__reset_preserved(qu); /* (but we just threw away the preserved stuff) */
 545
 546   qu->answer->status= adns_s_nomemory;
 547   free_query_allocs(qu);
 548 }
 549
 550 void adns__query_done(adns_query qu) {
 551   adns_answer *ans;
 552   adns_query parent;
 553
 554   adns__cancel_children(qu);
 555
 556   qu->id= -1;
 557   ans= qu->answer;
 558
 559   if (qu->flags & adns_qf_search && ans->status != adns_s_nomemory) {
 560     if (!save_owner(qu, qu->search_vb.buf, qu->search_vb.used)) {
 561       adns__query_fail(qu,adns_s_nomemory);
 562       return;
 563     }
 564   }
 565
 566   if (ans->nrrs && qu->typei->diff_needswap) {
 567     if (!adns__vbuf_ensure(&qu->vb,ans->rrsz)) {
 568       adns__query_fail(qu,adns_s_nomemory);
 569       return;
 570     }
 571     adns__isort(ans->rrs.bytes, ans->nrrs, ans->rrsz,
 572                 qu->vb.buf,
 573                 (int(*)(void*, const void*, const void*))
 574                   qu->typei->diff_needswap,
 575                 qu->ads);
 576   }
 577   if (ans->nrrs && qu->typei->postsort) {
 578     qu->typei->postsort(qu->ads, ans->rrs.bytes, ans->nrrs, qu->typei);
 579   }
 580
 581   ans->expires= qu->expires;
 582   parent= qu->parent;
 583   if (parent) {
 584     LIST_UNLINK_PART(parent->children,qu,siblings.);
 585     LIST_UNLINK(qu->ads->childw,parent);
 586     qu->ctx.callback(parent,qu);
 587     free_query_allocs(qu);
 588     free(qu->answer);
 589     free(qu);
 590   } else {
 591     makefinal_query(qu);
 592     LIST_LINK_TAIL(qu->ads->output,qu);
 593     qu->state= query_done;
 594   }
 595 }
 596
 597 void adns__query_fail(adns_query qu, adns_status stat) {
 598   adns__reset_preserved(qu);
 599   qu->answer->status= stat;
 600   adns__query_done(qu);
 601 }
 602
 603 void adns__makefinal_str(adns_query qu, char **strp) {
 604   int l;
 605   char *before, *after;
 606
 607   before= *strp;
 608   if (!before) return;
 609   l= strlen(before)+1;
 610   after= adns__alloc_final(qu,l);
 611   memcpy(after,before,l);
 612   *strp= after;
 613 }
 614
 615 void adns__makefinal_block(adns_query qu, void **blpp, size_t sz) {
 616   void *before, *after;
 617
 618   before= *blpp;
 619   if (!before) return;
 620   after= adns__alloc_final(qu,sz);
 621   memcpy(after,before,sz);
 622   *blpp= after;
 623 }