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   if (flags & adns__qf_nosend)
 109     ;
 110   else if (typei->query_send && !(flags & adns__qf_senddirect))
 111     typei->query_send(qu,now);
 112   else
 113     adns__query_send(qu, now);
 114 }
 115
 116 adns_status adns__internal_submit(adns_state ads, adns_query *query_r,
 117                                   const typeinfo *typei, adns_rrtype type,
 118                                   vbuf *qumsg_vb, int id,
 119                                   adns_queryflags flags, struct timeval now,
 120                                   const qcontext *ctx) {
 121   adns_query qu;
 122
 123   qu= query_alloc(ads,typei,type,flags & ~adns__qf_nosend,now);
 124   if (!qu) { adns__vbuf_free(qumsg_vb); return adns_s_nomemory; }
 125   *query_r= qu;
 126
 127   memcpy(&qu->ctx,ctx,sizeof(qu->ctx));
 128   query_submit(ads,qu, typei,qumsg_vb,id,flags,now);
 129
 130   return adns_s_ok;
 131 }
 132
 133 static void query_simple(adns_state ads, adns_query qu,
 134                          const char *owner, int ol,
 135                          const typeinfo *typei, adns_queryflags flags,
 136                          struct timeval now) {
 137   vbuf vb_new;
 138   int id;
 139   adns_status stat;
 140
 141   stat= adns__mkquery(ads,&qu->vb,&id, owner,ol,
 142                       typei,qu->answer->type, flags);
 143   if (stat) {
 144     if (stat == adns_s_querydomaintoolong && (flags & adns_qf_search)) {
 145       adns__search_next(ads,qu,now);
 146       return;
 147     } else {
 148       adns__query_fail(qu,stat);
 149       return;
 150     }
 151   }
 152
 153   vb_new= qu->vb;
 154   adns__vbuf_init(&qu->vb);
 155   query_submit(ads,qu, typei,&vb_new,id, flags,now);
 156 }
 157
 158 void adns__search_next(adns_state ads, adns_query qu, struct timeval now) {
 159   const char *nextentry;
 160   adns_status stat;
 161
 162   if (qu->search_doneabs<0) {
 163     nextentry= 0;
 164     qu->search_doneabs= 1;
 165   } else {
 166     if (qu->search_pos >= ads->nsearchlist) {
 167       if (qu->search_doneabs) {
 168         qu->search_vb.used= qu->search_origlen;
 169         stat= adns_s_nxdomain; goto x_fail;
 170       } else {
 171         nextentry= 0;
 172         qu->search_doneabs= 1;
 173       }
 174     } else {
 175       nextentry= ads->searchlist[qu->search_pos++];
 176     }
 177   }
 178
 179   qu->search_vb.used= qu->search_origlen;
 180   if (nextentry) {
 181     if (!adns__vbuf_append(&qu->search_vb,".",1) ||
 182         !adns__vbuf_appendstr(&qu->search_vb,nextentry))
 183       goto x_nomemory;
 184   }
 185
 186   free(qu->query_dgram);
 187   qu->query_dgram= 0; qu->query_dglen= 0;
 188
 189   query_simple(ads,qu, qu->search_vb.buf, qu->search_vb.used,
 190                qu->typei, qu->flags, now);
 191   return;
 192
 193 x_nomemory:
 194   stat= adns_s_nomemory;
 195 x_fail:
 196   adns__query_fail(qu,stat);
 197 }
 198
 199 static int save_owner(adns_query qu, const char *owner, int ol) {
 200   /* Returns 1 if OK, otherwise there was no memory. */
 201   adns_answer *ans;
 202
 203   if (!(qu->flags & adns_qf_owner)) return 1;
 204
 205   ans= qu->answer;
 206   assert(!ans->owner);
 207
 208   ans->owner= adns__alloc_preserved(qu,ol+1);  if (!ans->owner) return 0;
 209
 210   memcpy(ans->owner,owner,ol);
 211   ans->owner[ol]= 0;
 212   return 1;
 213 }
 214
 215 int adns_submit(adns_state ads,
 216                 const char *owner,
 217                 adns_rrtype type,
 218                 adns_queryflags flags,
 219                 void *context,
 220                 adns_query *query_r) {
 221   int r, ol, ndots;
 222   adns_status stat;
 223   const typeinfo *typei;
 224   struct timeval now;
 225   adns_query qu;
 226   const char *p;
 227
 228   adns__consistency(ads,0,cc_entex);
 229
 230   if (!(type & adns__qtf_bigaddr) || !(type & adns__qtf_manyaf))
 231     flags = (flags & ~adns__qf_afmask) | adns_qf_ipv4_only;
 232
 233   typei= adns__findtype(type);
 234   if (!typei) return ENOSYS;
 235
 236   r= gettimeofday(&now,0); if (r) goto x_errno;
 237   qu= query_alloc(ads,typei,type,flags,now); if (!qu) goto x_errno;
 238
 239   qu->ctx.ext= context;
 240   qu->ctx.callback= 0;
 241   memset(&qu->ctx.info,0,sizeof(qu->ctx.info));
 242
 243   *query_r= qu;
 244
 245   ol= strlen(owner);
 246   if (!ol) { stat= adns_s_querydomaininvalid; goto x_adnsfail; }
 247   if (ol>DNS_MAXDOMAIN+1) { stat= adns_s_querydomaintoolong; goto x_adnsfail; }
 248
 249   if (ol>=1 && owner[ol-1]=='.' && (ol<2 || owner[ol-2]!='\\')) {
 250     flags &= ~adns_qf_search;
 251     qu->flags= flags;
 252     ol--;
 253   }
 254
 255   if (flags & adns_qf_search) {
 256     r= adns__vbuf_append(&qu->search_vb,owner,ol);
 257     if (!r) { stat= adns_s_nomemory; goto x_adnsfail; }
 258
 259     for (ndots=0, p=owner; (p= strchr(p,'.')); p++, ndots++);
 260     qu->search_doneabs= (ndots >= ads->searchndots) ? -1 : 0;
 261     qu->search_origlen= ol;
 262     adns__search_next(ads,qu,now);
 263   } else {
 264     if (flags & adns_qf_owner) {
 265       if (!save_owner(qu,owner,ol)) { stat= adns_s_nomemory; goto x_adnsfail; }
 266     }
 267     query_simple(ads,qu, owner,ol, typei,flags, now);
 268   }
 269   adns__autosys(ads,now);
 270   adns__consistency(ads,qu,cc_entex);
 271   return 0;
 272
 273  x_adnsfail:
 274   adns__query_fail(qu,stat);
 275   adns__consistency(ads,qu,cc_entex);
 276   return 0;
 277
 278  x_errno:
 279   r= errno;
 280   assert(r);
 281   adns__consistency(ads,0,cc_entex);
 282   return r;
 283 }
 284
 285 static const char *default_zone = "<magic>";
 286
 287 int adns_submit_reverse_any(adns_state ads,
 288                             const struct sockaddr *addr,
 289                             const char *zone,
 290                             adns_rrtype type,
 291                             adns_queryflags flags,
 292                             void *context,
 293                             adns_query *query_r) {
 294   char *buf, *buf_free, *p;
 295   char shortbuf[100];
 296   const afinfo *ai;
 297   int r, lreq;
 298
 299   flags &= ~adns_qf_search;
 300
 301   switch (addr->sa_family) {
 302     case AF_INET:
 303       ai = &adns__inet_afinfo;
 304       if (zone == default_zone) zone = "in-addr.arpa";
 305       break;
 306     case AF_INET6:
 307       ai = &adns__inet6_afinfo;
 308       if (zone == default_zone) zone = "ip6.arpa";
 309       break;
 310     default:
 311       return ENOSYS;
 312   }
 313
 314   lreq= strlen(zone) + ai->nrevcomp*(ai->revcompwd + 1) + 1;
 315   if (lreq > sizeof(shortbuf)) {
 316     buf= malloc(lreq);
 317     if (!buf) return errno;
 318     buf_free= buf;
 319   } else {
 320     buf= shortbuf;
 321     buf_free= 0;
 322   }
 323
 324   p = ai->rev_mkname(addr, buf);
 325   *p++ = '.';
 326   strcpy(p, zone);
 327
 328   r= adns_submit(ads,buf,type,flags,context,query_r);
 329   free(buf_free);
 330   return r;
 331 }
 332
 333 int adns_submit_reverse(adns_state ads,
 334                         const struct sockaddr *addr,
 335                         adns_rrtype type,
 336                         adns_queryflags flags,
 337                         void *context,
 338                         adns_query *query_r) {
 339   if (type != adns_r_ptr && type != adns_r_ptr_raw) return EINVAL;
 340   return adns_submit_reverse_any(ads,addr,default_zone,
 341                                  type,flags,context,query_r);
 342 }
 343
 344 int adns_synchronous(adns_state ads,
 345                      const char *owner,
 346                      adns_rrtype type,
 347                      adns_queryflags flags,
 348                      adns_answer **answer_r) {
 349   adns_query qu;
 350   int r;
 351
 352   r= adns_submit(ads,owner,type,flags,0,&qu);
 353   if (r) return r;
 354
 355   r= adns_wait(ads,&qu,answer_r,0);
 356   if (r) adns_cancel(qu);
 357
 358   return r;
 359 }
 360
 361 static void *alloc_common(adns_query qu, size_t sz) {
 362   allocnode *an;
 363
 364   if (!sz) return qu; /* Any old pointer will do */
 365   assert(!qu->final_allocspace);
 366   an= malloc(MEM_ROUND(MEM_ROUND(sizeof(*an)) + sz));
 367   if (!an) return 0;
 368   LIST_LINK_TAIL(qu->allocations,an);
 369   an->sz = sz;
 370   return (byte*)an + MEM_ROUND(sizeof(*an));
 371 }
 372
 373 void *adns__alloc_interim(adns_query qu, size_t sz) {
 374   void *rv;
 375
 376   sz= MEM_ROUND(sz);
 377   rv= alloc_common(qu,sz);
 378   if (!rv) return 0;
 379   qu->interim_allocd += sz;
 380   return rv;
 381 }
 382
 383 void *adns__alloc_preserved(adns_query qu, size_t sz) {
 384   void *rv;
 385
 386   sz= MEM_ROUND(sz);
 387   rv= adns__alloc_interim(qu,sz);
 388   if (!rv) return 0;
 389   qu->preserved_allocd += sz;
 390   return rv;
 391 }
 392
 393 void adns__free_interim(adns_query qu, void *p) {
 394   allocnode *an;
 395   size_t sz;
 396
 397   if (!p) return;
 398   an = (allocnode *)((byte *)p - MEM_ROUND(sizeof(allocnode)));
 399   sz = MEM_ROUND(an->sz);
 400   LIST_UNLINK(qu->allocations, an);
 401   free(an);
 402   qu->interim_allocd -= sz;
 403 }
 404
 405 void *adns__alloc_mine(adns_query qu, size_t sz) {
 406   return alloc_common(qu,MEM_ROUND(sz));
 407 }
 408
 409 void adns__transfer_interim(adns_query from, adns_query to,
 410                             void *block, size_t sz) {
 411   allocnode *an;
 412
 413   if (!block) return;
 414   an= (void*)((byte*)block - MEM_ROUND(sizeof(*an)));
 415
 416   assert(!to->final_allocspace);
 417   assert(!from->final_allocspace);
 418
 419   LIST_UNLINK(from->allocations,an);
 420   LIST_LINK_TAIL(to->allocations,an);
 421
 422   sz= MEM_ROUND(sz);
 423   from->interim_allocd -= sz;
 424   to->interim_allocd += sz;
 425
 426   if (to->expires > from->expires) to->expires= from->expires;
 427 }
 428
 429 void *adns__alloc_final(adns_query qu, size_t sz) {
 430   /* When we're in the _final stage, we _subtract_ from interim_alloc'd
 431    * each allocation, and use final_allocspace to point to the next free
 432    * bit.
 433    */
 434   void *rp;
 435
 436   sz= MEM_ROUND(sz);
 437   rp= qu->final_allocspace;
 438   assert(rp);
 439   qu->interim_allocd -= sz;
 440   assert(qu->interim_allocd>=0);
 441   qu->final_allocspace= (byte*)rp + sz;
 442   return rp;
 443 }
 444
 445 void adns__cancel_children(adns_query qu) {
 446   adns_query cqu, ncqu;
 447
 448   for (cqu= qu->children.head; cqu; cqu= ncqu) {
 449     ncqu= cqu->siblings.next;
 450     adns_cancel(cqu);
 451   }
 452 }
 453
 454 void adns__reset_preserved(adns_query qu) {
 455   assert(!qu->final_allocspace);
 456   adns__cancel_children(qu);
 457   qu->answer->nrrs= 0;
 458   qu->answer->rrs.untyped= 0;
 459   qu->interim_allocd= qu->preserved_allocd;
 460 }
 461
 462 static void free_query_allocs(adns_query qu) {
 463   allocnode *an, *ann;
 464
 465   adns__cancel_children(qu);
 466   for (an= qu->allocations.head; an; an= ann) { ann= an->next; free(an); }
 467   LIST_INIT(qu->allocations);
 468   adns__vbuf_free(&qu->vb);
 469   adns__vbuf_free(&qu->search_vb);
 470   free(qu->query_dgram);
 471   qu->query_dgram= 0;
 472 }
 473
 474 void adns_cancel(adns_query qu) {
 475   adns_state ads;
 476
 477   ads= qu->ads;
 478   adns__consistency(ads,qu,cc_entex);
 479   if (qu->parent) LIST_UNLINK_PART(qu->parent->children,qu,siblings.);
 480   switch (qu->state) {
 481   case query_tosend:
 482     LIST_UNLINK(ads->udpw,qu);
 483     break;
 484   case query_tcpw:
 485     LIST_UNLINK(ads->tcpw,qu);
 486     break;
 487   case query_childw:
 488     LIST_UNLINK(ads->childw,qu);
 489     break;
 490   case query_done:
 491     LIST_UNLINK(ads->output,qu);
 492     break;
 493   default:
 494     abort();
 495   }
 496   free_query_allocs(qu);
 497   free(qu->answer);
 498   free(qu);
 499   adns__consistency(ads,0,cc_entex);
 500 }
 501
 502 void adns__update_expires(adns_query qu, unsigned long ttl,
 503                           struct timeval now) {
 504   time_t max;
 505
 506   assert(ttl <= MAXTTLBELIEVE);
 507   max= now.tv_sec + ttl;
 508   if (qu->expires < max) return;
 509   qu->expires= max;
 510 }
 511
 512 static void makefinal_query(adns_query qu) {
 513   adns_answer *ans;
 514   int rrn;
 515
 516   ans= qu->answer;
 517
 518   if (qu->interim_allocd) {
 519     ans= realloc(qu->answer,
 520                  MEM_ROUND(MEM_ROUND(sizeof(*ans)) + qu->interim_allocd));
 521     if (!ans) goto x_nomem;
 522     qu->answer= ans;
 523   }
 524
 525   qu->final_allocspace= (byte*)ans + MEM_ROUND(sizeof(*ans));
 526   adns__makefinal_str(qu,&ans->cname);
 527   adns__makefinal_str(qu,&ans->owner);
 528
 529   if (ans->nrrs) {
 530     adns__makefinal_block(qu, &ans->rrs.untyped, ans->nrrs*ans->rrsz);
 531
 532     for (rrn=0; rrn<ans->nrrs; rrn++)
 533       qu->typei->makefinal(qu, ans->rrs.bytes + rrn*ans->rrsz);
 534   }
 535
 536   free_query_allocs(qu);
 537   return;
 538
 539  x_nomem:
 540   qu->preserved_allocd= 0;
 541   qu->answer->cname= 0;
 542   qu->answer->owner= 0;
 543   adns__reset_preserved(qu); /* (but we just threw away the preserved stuff) */
 544
 545   qu->answer->status= adns_s_nomemory;
 546   free_query_allocs(qu);
 547 }
 548
 549 void adns__query_done(adns_query qu) {
 550   adns_answer *ans;
 551   adns_query parent;
 552
 553   adns__cancel_children(qu);
 554
 555   qu->id= -1;
 556   ans= qu->answer;
 557
 558   if (qu->flags & adns_qf_search && ans->status != adns_s_nomemory) {
 559     if (!save_owner(qu, qu->search_vb.buf, qu->search_vb.used)) {
 560       adns__query_fail(qu,adns_s_nomemory);
 561       return;
 562     }
 563   }
 564
 565   if (ans->nrrs && qu->typei->diff_needswap) {
 566     if (!adns__vbuf_ensure(&qu->vb,ans->rrsz)) {
 567       adns__query_fail(qu,adns_s_nomemory);
 568       return;
 569     }
 570     adns__isort(ans->rrs.bytes, ans->nrrs, ans->rrsz,
 571                 qu->vb.buf,
 572                 (int(*)(void*, const void*, const void*))
 573                   qu->typei->diff_needswap,
 574                 qu->ads);
 575   }
 576   if (ans->nrrs && qu->typei->postsort) {
 577     qu->typei->postsort(qu->ads, ans->rrs.bytes, ans->nrrs, qu->typei);
 578   }
 579
 580   ans->expires= qu->expires;
 581   parent= qu->parent;
 582   if (parent) {
 583     LIST_UNLINK_PART(parent->children,qu,siblings.);
 584     LIST_UNLINK(qu->ads->childw,parent);
 585     qu->ctx.callback(parent,qu);
 586     free_query_allocs(qu);
 587     free(qu->answer);
 588     free(qu);
 589   } else {
 590     makefinal_query(qu);
 591     LIST_LINK_TAIL(qu->ads->output,qu);
 592     qu->state= query_done;
 593   }
 594 }
 595
 596 void adns__query_fail(adns_query qu, adns_status stat) {
 597   adns__reset_preserved(qu);
 598   qu->answer->status= stat;
 599   adns__query_done(qu);
 600 }
 601
 602 void adns__makefinal_str(adns_query qu, char **strp) {
 603   int l;
 604   char *before, *after;
 605
 606   before= *strp;
 607   if (!before) return;
 608   l= strlen(before)+1;
 609   after= adns__alloc_final(qu,l);
 610   memcpy(after,before,l);
 611   *strp= after;
 612 }
 613
 614 void adns__makefinal_block(adns_query qu, void **blpp, size_t sz) {
 615   void *before, *after;
 616
 617   before= *blpp;
 618   if (!before) return;
 619   after= adns__alloc_final(qu,sz);
 620   memcpy(after,before,sz);
 621   *blpp= after;
 622 }