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