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,type);
  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   typei->query_send(qu,now);
 109 }
 110
 111 adns_status adns__ckl_hostname(adns_state ads, adns_queryflags flags,
 112                                union checklabel_state *cls,
 113                                qcontext *ctx, int labnum,
 114                                const char *dgram, int labstart, int lablen)
 115 {
 116   int i, c;
 117   const char *label = dgram+labstart;
 118
 119   if (flags & adns_qf_quoteok_query) return adns_s_ok;
 120   for (i=0; i<lablen; i++) {
 121     c= label[i];
 122     if (c == '-') {
 123       if (!i) return adns_s_querydomaininvalid;
 124     } else if (!ctype_alpha(c) && !ctype_digit(c)) {
 125       return adns_s_querydomaininvalid;
 126     }
 127   }
 128   return adns_s_ok;
 129 }
 130
 131 static adns_status check_domain_name(adns_state ads, adns_queryflags flags,
 132                                      qcontext *ctx, const typeinfo *typei,
 133                                      const byte *dgram, int dglen)
 134 {
 135   findlabel_state fls;
 136   adns_status err;
 137   int labnum= 0, labstart, lablen;
 138   union checklabel_state cls;
 139
 140   adns__findlabel_start(&fls,ads, -1,0, dgram,dglen,dglen, DNS_HDRSIZE,0);
 141   do {
 142     err= adns__findlabel_next(&fls, &lablen,&labstart);
 143     assert(!err); assert(lablen >= 0);
 144     err= typei->checklabel(ads,flags, &cls,ctx,
 145                            labnum++, dgram,labstart,lablen);
 146     if (err) return err;
 147   } while (lablen);
 148   return adns_s_ok;
 149 }
 150
 151 adns_status adns__internal_submit(adns_state ads, adns_query *query_r,
 152                                   const typeinfo *typei, adns_rrtype type,
 153                                   vbuf *qumsg_vb, int id,
 154                                   adns_queryflags flags, struct timeval now,
 155                                   qcontext *ctx) {
 156   adns_query qu;
 157   adns_status err;
 158
 159   err= check_domain_name(ads, flags,ctx,typei, qumsg_vb->buf,qumsg_vb->used);
 160   if (err) goto x_err;
 161   qu= query_alloc(ads,typei,type,flags,now);
 162   if (!qu) { err = adns_s_nomemory; goto x_err; }
 163   *query_r= qu;
 164
 165   memcpy(&qu->ctx,ctx,sizeof(qu->ctx));
 166   query_submit(ads,qu, typei,qumsg_vb,id,flags,now);
 167
 168   return adns_s_ok;
 169
 170 x_err:
 171   adns__vbuf_free(qumsg_vb);
 172   return err;
 173 }
 174
 175 static void query_simple(adns_state ads, adns_query qu,
 176                          const char *owner, int ol,
 177                          const typeinfo *typei, adns_queryflags flags,
 178                          struct timeval now) {
 179   vbuf vb_new;
 180   int id;
 181   adns_status stat;
 182
 183   stat= adns__mkquery(ads,&qu->vb,&id, owner,ol,
 184                       typei,qu->answer->type, flags);
 185   if (stat) {
 186     if (stat == adns_s_querydomaintoolong && (flags & adns_qf_search)) {
 187       adns__search_next(ads,qu,now);
 188       return;
 189     } else {
 190       adns__query_fail(qu,stat);
 191       return;
 192     }
 193   }
 194
 195   stat= check_domain_name(ads, flags,&qu->ctx,typei, qu->vb.buf,qu->vb.used);
 196   if (stat) { adns__query_fail(qu,stat); return; }
 197
 198   vb_new= qu->vb;
 199   adns__vbuf_init(&qu->vb);
 200   query_submit(ads,qu, typei,&vb_new,id, flags,now);
 201 }
 202
 203 void adns__search_next(adns_state ads, adns_query qu, struct timeval now) {
 204   const char *nextentry;
 205   adns_status stat;
 206
 207   if (qu->search_doneabs<0) {
 208     nextentry= 0;
 209     qu->search_doneabs= 1;
 210   } else {
 211     if (qu->search_pos >= ads->nsearchlist) {
 212       if (qu->search_doneabs) {
 213         qu->search_vb.used= qu->search_origlen;
 214         stat= adns_s_nxdomain; goto x_fail;
 215       } else {
 216         nextentry= 0;
 217         qu->search_doneabs= 1;
 218       }
 219     } else {
 220       nextentry= ads->searchlist[qu->search_pos++];
 221     }
 222   }
 223
 224   qu->search_vb.used= qu->search_origlen;
 225   if (nextentry) {
 226     if (!adns__vbuf_append(&qu->search_vb,".",1) ||
 227         !adns__vbuf_appendstr(&qu->search_vb,nextentry))
 228       goto x_nomemory;
 229   }
 230
 231   free(qu->query_dgram);
 232   qu->query_dgram= 0; qu->query_dglen= 0;
 233
 234   query_simple(ads,qu, qu->search_vb.buf, qu->search_vb.used,
 235                qu->typei, qu->flags, now);
 236   return;
 237
 238 x_nomemory:
 239   stat= adns_s_nomemory;
 240 x_fail:
 241   adns__query_fail(qu,stat);
 242 }
 243
 244 static int save_owner(adns_query qu, const char *owner, int ol) {
 245   /* Returns 1 if OK, otherwise there was no memory. */
 246   adns_answer *ans;
 247
 248   if (!(qu->flags & adns_qf_owner)) return 1;
 249
 250   ans= qu->answer;
 251   assert(!ans->owner);
 252
 253   ans->owner= adns__alloc_preserved(qu,ol+1);  if (!ans->owner) return 0;
 254
 255   memcpy(ans->owner,owner,ol);
 256   ans->owner[ol]= 0;
 257   return 1;
 258 }
 259
 260 int adns_submit(adns_state ads,
 261                 const char *owner,
 262                 adns_rrtype type,
 263                 adns_queryflags flags,
 264                 void *context,
 265                 adns_query *query_r) {
 266   int r, ol, ndots;
 267   adns_status stat;
 268   const typeinfo *typei;
 269   struct timeval now;
 270   adns_query qu;
 271   const char *p;
 272
 273   adns__consistency(ads,0,cc_entex);
 274
 275   typei= adns__findtype(type);
 276   if (!typei) return ENOSYS;
 277
 278   r= gettimeofday(&now,0); if (r) goto x_errno;
 279   qu= query_alloc(ads,typei,type,flags,now); if (!qu) goto x_errno;
 280
 281   qu->ctx.ext= context;
 282   qu->ctx.callback= 0;
 283   memset(&qu->ctx.pinfo,0,sizeof(qu->ctx.pinfo));
 284   memset(&qu->ctx.tinfo,0,sizeof(qu->ctx.tinfo));
 285
 286   *query_r= qu;
 287
 288   ol= strlen(owner);
 289   if (!ol) { stat= adns_s_querydomaininvalid; goto x_adnsfail; }
 290   if (ol>DNS_MAXDOMAIN+1) { stat= adns_s_querydomaintoolong; goto x_adnsfail; }
 291
 292   if (ol>=1 && owner[ol-1]=='.' && (ol<2 || owner[ol-2]!='\\')) {
 293     flags &= ~adns_qf_search;
 294     qu->flags= flags;
 295     ol--;
 296   }
 297
 298   if (flags & adns_qf_search) {
 299     r= adns__vbuf_append(&qu->search_vb,owner,ol);
 300     if (!r) { stat= adns_s_nomemory; goto x_adnsfail; }
 301
 302     for (ndots=0, p=owner; (p= strchr(p,'.')); p++, ndots++);
 303     qu->search_doneabs= (ndots >= ads->searchndots) ? -1 : 0;
 304     qu->search_origlen= ol;
 305     adns__search_next(ads,qu,now);
 306   } else {
 307     if (flags & adns_qf_owner) {
 308       if (!save_owner(qu,owner,ol)) { stat= adns_s_nomemory; goto x_adnsfail; }
 309     }
 310     query_simple(ads,qu, owner,ol, typei,flags, now);
 311   }
 312   adns__autosys(ads,now);
 313   adns__consistency(ads,qu,cc_entex);
 314   return 0;
 315
 316  x_adnsfail:
 317   adns__query_fail(qu,stat);
 318   adns__consistency(ads,qu,cc_entex);
 319   return 0;
 320
 321  x_errno:
 322   r= errno;
 323   assert(r);
 324   adns__consistency(ads,0,cc_entex);
 325   return r;
 326 }
 327
 328 int adns_submit_reverse_any(adns_state ads,
 329                             const struct sockaddr *addr,
 330                             const char *zone,
 331                             adns_rrtype type,
 332                             adns_queryflags flags,
 333                             void *context,
 334                             adns_query *query_r) {
 335   char *buf, *buf_free = 0;
 336   char shortbuf[100];
 337   int r;
 338
 339   flags &= ~adns_qf_search;
 340
 341   buf = shortbuf;
 342   r= adns__make_reverse_domain(addr,zone, &buf,sizeof(shortbuf),&buf_free);
 343   if (r) return r;
 344   r= adns_submit(ads,buf,type,flags,context,query_r);
 345   free(buf_free);
 346   return r;
 347 }
 348
 349 int adns_submit_reverse(adns_state ads,
 350                         const struct sockaddr *addr,
 351                         adns_rrtype type,
 352                         adns_queryflags flags,
 353                         void *context,
 354                         adns_query *query_r) {
 355   if (((type^adns_r_ptr) & adns_rrt_reprmask) &&
 356       ((type^adns_r_ptr_raw) & adns_rrt_reprmask))
 357     return EINVAL;
 358   return adns_submit_reverse_any(ads,addr,0,type,flags,context,query_r);
 359 }
 360
 361 int adns_synchronous(adns_state ads,
 362                      const char *owner,
 363                      adns_rrtype type,
 364                      adns_queryflags flags,
 365                      adns_answer **answer_r) {
 366   adns_query qu;
 367   int r;
 368
 369   r= adns_submit(ads,owner,type,flags,0,&qu);
 370   if (r) return r;
 371
 372   r= adns_wait(ads,&qu,answer_r,0);
 373   if (r) adns_cancel(qu);
 374
 375   return r;
 376 }
 377
 378 static void *alloc_common(adns_query qu, size_t sz) {
 379   allocnode *an;
 380
 381   if (!sz) return qu; /* Any old pointer will do */
 382   assert(!qu->final_allocspace);
 383   an= malloc(MEM_ROUND(MEM_ROUND(sizeof(*an)) + sz));
 384   if (!an) return 0;
 385   LIST_LINK_TAIL(qu->allocations,an);
 386   an->sz= sz;
 387   return (byte*)an + MEM_ROUND(sizeof(*an));
 388 }
 389
 390 void *adns__alloc_interim(adns_query qu, size_t sz) {
 391   void *rv;
 392
 393   sz= MEM_ROUND(sz);
 394   rv= alloc_common(qu,sz);
 395   if (!rv) return 0;
 396   qu->interim_allocd += sz;
 397   return rv;
 398 }
 399
 400 void *adns__alloc_preserved(adns_query qu, size_t sz) {
 401   void *rv;
 402
 403   sz= MEM_ROUND(sz);
 404   rv= adns__alloc_interim(qu,sz);
 405   if (!rv) return 0;
 406   qu->preserved_allocd += sz;
 407   return rv;
 408 }
 409
 410 static allocnode *alloc_info(adns_query qu, void *p, size_t *sz_r) {
 411   allocnode *an;
 412
 413   if (!p || p == qu) { *sz_r= 0; return 0; }
 414   an= (allocnode *)((byte *)p - MEM_ROUND(sizeof(allocnode)));
 415   *sz_r= MEM_ROUND(an->sz);
 416   return an;
 417 }
 418
 419 void adns__free_interim(adns_query qu, void *p) {
 420   size_t sz;
 421   allocnode *an= alloc_info(qu, p, &sz);
 422
 423   if (!an) return;
 424   assert(!qu->final_allocspace);
 425   LIST_UNLINK(qu->allocations, an);
 426   free(an);
 427   qu->interim_allocd -= sz;
 428 }
 429
 430 void *adns__alloc_mine(adns_query qu, size_t sz) {
 431   return alloc_common(qu,MEM_ROUND(sz));
 432 }
 433
 434 void adns__transfer_interim(adns_query from, adns_query to, void *block) {
 435   size_t sz;
 436   allocnode *an= alloc_info(from, block, &sz);
 437
 438   if (!an) return;
 439
 440   assert(!to->final_allocspace);
 441   assert(!from->final_allocspace);
 442
 443   LIST_UNLINK(from->allocations,an);
 444   LIST_LINK_TAIL(to->allocations,an);
 445
 446   from->interim_allocd -= sz;
 447   to->interim_allocd += sz;
 448
 449   if (to->expires > from->expires) to->expires= from->expires;
 450 }
 451
 452 void *adns__alloc_final(adns_query qu, size_t sz) {
 453   /* When we're in the _final stage, we _subtract_ from interim_alloc'd
 454    * each allocation, and use final_allocspace to point to the next free
 455    * bit.
 456    */
 457   void *rp;
 458
 459   sz= MEM_ROUND(sz);
 460   rp= qu->final_allocspace;
 461   assert(rp);
 462   qu->interim_allocd -= sz;
 463   assert(qu->interim_allocd>=0);
 464   qu->final_allocspace= (byte*)rp + sz;
 465   return rp;
 466 }
 467
 468 void adns__cancel_children(adns_query qu) {
 469   adns_query cqu, ncqu;
 470
 471   for (cqu= qu->children.head; cqu; cqu= ncqu) {
 472     ncqu= cqu->siblings.next;
 473     adns_cancel(cqu);
 474   }
 475 }
 476
 477 void adns__reset_preserved(adns_query qu) {
 478   assert(!qu->final_allocspace);
 479   adns__cancel_children(qu);
 480   qu->answer->nrrs= 0;
 481   qu->answer->rrs.untyped= 0;
 482   qu->interim_allocd= qu->preserved_allocd;
 483 }
 484
 485 static void free_query_allocs(adns_query qu) {
 486   allocnode *an, *ann;
 487
 488   adns__cancel_children(qu);
 489   for (an= qu->allocations.head; an; an= ann) { ann= an->next; free(an); }
 490   LIST_INIT(qu->allocations);
 491   adns__vbuf_free(&qu->vb);
 492   adns__vbuf_free(&qu->search_vb);
 493   free(qu->query_dgram);
 494   qu->query_dgram= 0;
 495 }
 496
 497 void adns_cancel(adns_query qu) {
 498   adns_state ads;
 499
 500   ads= qu->ads;
 501   adns__consistency(ads,qu,cc_entex);
 502   if (qu->parent) LIST_UNLINK_PART(qu->parent->children,qu,siblings.);
 503   switch (qu->state) {
 504   case query_tosend:
 505     LIST_UNLINK(ads->udpw,qu);
 506     break;
 507   case query_tcpw:
 508     LIST_UNLINK(ads->tcpw,qu);
 509     break;
 510   case query_childw:
 511     LIST_UNLINK(ads->childw,qu);
 512     break;
 513   case query_done:
 514     LIST_UNLINK(ads->output,qu);
 515     break;
 516   default:
 517     abort();
 518   }
 519   free_query_allocs(qu);
 520   free(qu->answer);
 521   free(qu);
 522   adns__consistency(ads,0,cc_entex);
 523 }
 524
 525 void adns__update_expires(adns_query qu, unsigned long ttl,
 526                           struct timeval now) {
 527   time_t max;
 528
 529   assert(ttl <= MAXTTLBELIEVE);
 530   max= now.tv_sec + ttl;
 531   if (qu->expires < max) return;
 532   qu->expires= max;
 533 }
 534
 535 static void makefinal_query(adns_query qu) {
 536   adns_answer *ans;
 537   int rrn;
 538
 539   ans= qu->answer;
 540
 541   if (qu->interim_allocd) {
 542     ans= realloc(qu->answer,
 543                  MEM_ROUND(MEM_ROUND(sizeof(*ans)) + qu->interim_allocd));
 544     if (!ans) goto x_nomem;
 545     qu->answer= ans;
 546   }
 547
 548   qu->final_allocspace= (byte*)ans + MEM_ROUND(sizeof(*ans));
 549   adns__makefinal_str(qu,&ans->cname);
 550   adns__makefinal_str(qu,&ans->owner);
 551
 552   if (ans->nrrs) {
 553     adns__makefinal_block(qu, &ans->rrs.untyped, ans->nrrs*ans->rrsz);
 554
 555     for (rrn=0; rrn<ans->nrrs; rrn++)
 556       qu->typei->makefinal(qu, ans->rrs.bytes + rrn*ans->rrsz);
 557   }
 558
 559   free_query_allocs(qu);
 560   return;
 561
 562  x_nomem:
 563   qu->preserved_allocd= 0;
 564   qu->answer->cname= 0;
 565   qu->answer->owner= 0;
 566   adns__reset_preserved(qu); /* (but we just threw away the preserved stuff) */
 567
 568   qu->answer->status= adns_s_nomemory;
 569   free_query_allocs(qu);
 570 }
 571
 572 void adns__query_done(adns_query qu) {
 573   adns_answer *ans;
 574   adns_query parent;
 575
 576   adns__cancel_children(qu);
 577
 578   qu->id= -1;
 579   ans= qu->answer;
 580
 581   if (qu->flags & adns_qf_search && ans->status != adns_s_nomemory) {
 582     if (!save_owner(qu, qu->search_vb.buf, qu->search_vb.used)) {
 583       adns__query_fail(qu,adns_s_nomemory);
 584       return;
 585     }
 586   }
 587
 588   if (ans->nrrs && qu->typei->diff_needswap) {
 589     if (!adns__vbuf_ensure(&qu->vb,qu->answer->rrsz)) {
 590       adns__query_fail(qu,adns_s_nomemory);
 591       return;
 592     }
 593     adns__isort(ans->rrs.bytes, ans->nrrs, ans->rrsz,
 594                 qu->vb.buf,
 595                 (int(*)(void*, const void*, const void*))
 596                   qu->typei->diff_needswap,
 597                 qu->ads);
 598   }
 599   if (ans->nrrs && qu->typei->postsort) {
 600     qu->typei->postsort(qu->ads, ans->rrs.bytes,
 601                         ans->nrrs,ans->rrsz, qu->typei);
 602   }
 603
 604   ans->expires= qu->expires;
 605   parent= qu->parent;
 606   if (parent) {
 607     LIST_UNLINK_PART(parent->children,qu,siblings.);
 608     LIST_UNLINK(qu->ads->childw,parent);
 609     qu->ctx.callback(parent,qu);
 610     free_query_allocs(qu);
 611     free(qu->answer);
 612     free(qu);
 613   } else {
 614     makefinal_query(qu);
 615     LIST_LINK_TAIL(qu->ads->output,qu);
 616     qu->state= query_done;
 617   }
 618 }
 619
 620 void adns__query_fail(adns_query qu, adns_status stat) {
 621   adns__reset_preserved(qu);
 622   qu->answer->status= stat;
 623   adns__query_done(qu);
 624 }
 625
 626 void adns__makefinal_str(adns_query qu, char **strp) {
 627   int l;
 628   char *before, *after;
 629
 630   before= *strp;
 631   if (!before) return;
 632   l= strlen(before)+1;
 633   after= adns__alloc_final(qu,l);
 634   memcpy(after,before,l);
 635   *strp= after;
 636 }
 637
 638 void adns__makefinal_block(adns_query qu, void **blpp, size_t sz) {
 639   void *before, *after;
 640
 641   before= *blpp;
 642   if (!before) return;
 643   after= adns__alloc_final(qu,sz);
 644   memcpy(after,before,sz);
 645   *blpp= after;
 646 }