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__ckl_hostname(adns_state ads, adns_queryflags flags,
 113                                union checklabel_state *css,
 114                                qcontext *ctx, int labnum,
 115                                const char *label, int lablen)
 116 {
 117   int i, c;
 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 css;
 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, &css,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 static const char *default_zone = "<magic>";
 329
 330 int adns_submit_reverse_any(adns_state ads,
 331                             const struct sockaddr *addr,
 332                             const char *zone,
 333                             adns_rrtype type,
 334                             adns_queryflags flags,
 335                             void *context,
 336                             adns_query *query_r) {
 337   char *buf, *buf_free, *p;
 338   char shortbuf[100];
 339   const afinfo *ai;
 340   int r, lreq;
 341
 342   flags &= ~adns_qf_search;
 343
 344   switch (addr->sa_family) {
 345     case AF_INET:
 346       ai = &adns__inet_afinfo;
 347       if (zone == default_zone) zone = "in-addr.arpa";
 348       break;
 349     case AF_INET6:
 350       ai = &adns__inet6_afinfo;
 351       if (zone == default_zone) zone = "ip6.arpa";
 352       break;
 353     default:
 354       return ENOSYS;
 355   }
 356
 357   lreq= strlen(zone) + ai->nrevcomp*(ai->revcompwd + 1) + 1;
 358   if (lreq > sizeof(shortbuf)) {
 359     buf= malloc(lreq);
 360     if (!buf) return errno;
 361     buf_free= buf;
 362   } else {
 363     buf= shortbuf;
 364     buf_free= 0;
 365   }
 366
 367   p = ai->rev_mkname(addr, buf);
 368   *p++ = '.';
 369   strcpy(p, zone);
 370
 371   r= adns_submit(ads,buf,type,flags,context,query_r);
 372   free(buf_free);
 373   return r;
 374 }
 375
 376 int adns_submit_reverse(adns_state ads,
 377                         const struct sockaddr *addr,
 378                         adns_rrtype type,
 379                         adns_queryflags flags,
 380                         void *context,
 381                         adns_query *query_r) {
 382   if (type != adns_r_ptr && type != adns_r_ptr_raw) return EINVAL;
 383   return adns_submit_reverse_any(ads,addr,default_zone,
 384                                  type,flags,context,query_r);
 385 }
 386
 387 int adns_synchronous(adns_state ads,
 388                      const char *owner,
 389                      adns_rrtype type,
 390                      adns_queryflags flags,
 391                      adns_answer **answer_r) {
 392   adns_query qu;
 393   int r;
 394
 395   r= adns_submit(ads,owner,type,flags,0,&qu);
 396   if (r) return r;
 397
 398   r= adns_wait(ads,&qu,answer_r,0);
 399   if (r) adns_cancel(qu);
 400
 401   return r;
 402 }
 403
 404 static void *alloc_common(adns_query qu, size_t sz) {
 405   allocnode *an;
 406
 407   if (!sz) return qu; /* Any old pointer will do */
 408   assert(!qu->final_allocspace);
 409   an= malloc(MEM_ROUND(MEM_ROUND(sizeof(*an)) + sz));
 410   if (!an) return 0;
 411   LIST_LINK_TAIL(qu->allocations,an);
 412   an->sz = sz;
 413   return (byte*)an + MEM_ROUND(sizeof(*an));
 414 }
 415
 416 void *adns__alloc_interim(adns_query qu, size_t sz) {
 417   void *rv;
 418
 419   sz= MEM_ROUND(sz);
 420   rv= alloc_common(qu,sz);
 421   if (!rv) return 0;
 422   qu->interim_allocd += sz;
 423   return rv;
 424 }
 425
 426 void *adns__alloc_preserved(adns_query qu, size_t sz) {
 427   void *rv;
 428
 429   sz= MEM_ROUND(sz);
 430   rv= adns__alloc_interim(qu,sz);
 431   if (!rv) return 0;
 432   qu->preserved_allocd += sz;
 433   return rv;
 434 }
 435
 436 static allocnode *alloc_info(adns_query qu, void *p, size_t *sz_r)
 437 {
 438   allocnode *an;
 439
 440   if (!p || p == qu) { *sz_r = 0; return 0; }
 441   an = (allocnode *)((byte *)p - MEM_ROUND(sizeof(allocnode)));
 442   *sz_r = MEM_ROUND(an->sz);
 443   return an;
 444 }
 445
 446 void adns__free_interim(adns_query qu, void *p) {
 447   size_t sz;
 448   allocnode *an = alloc_info(qu, p, &sz);
 449
 450   if (!an) return;
 451   assert(!qu->final_allocspace);
 452   LIST_UNLINK(qu->allocations, an);
 453   free(an);
 454   qu->interim_allocd -= sz;
 455 }
 456
 457 void *adns__alloc_mine(adns_query qu, size_t sz) {
 458   return alloc_common(qu,MEM_ROUND(sz));
 459 }
 460
 461 void adns__transfer_interim(adns_query from, adns_query to, void *block) {
 462   size_t sz;
 463   allocnode *an = alloc_info(from, block, &sz);
 464
 465   if (!an) return;
 466
 467   assert(!to->final_allocspace);
 468   assert(!from->final_allocspace);
 469
 470   LIST_UNLINK(from->allocations,an);
 471   LIST_LINK_TAIL(to->allocations,an);
 472
 473   from->interim_allocd -= sz;
 474   to->interim_allocd += sz;
 475
 476   if (to->expires > from->expires) to->expires= from->expires;
 477 }
 478
 479 void *adns__alloc_final(adns_query qu, size_t sz) {
 480   /* When we're in the _final stage, we _subtract_ from interim_alloc'd
 481    * each allocation, and use final_allocspace to point to the next free
 482    * bit.
 483    */
 484   void *rp;
 485
 486   sz= MEM_ROUND(sz);
 487   rp= qu->final_allocspace;
 488   assert(rp);
 489   qu->interim_allocd -= sz;
 490   assert(qu->interim_allocd>=0);
 491   qu->final_allocspace= (byte*)rp + sz;
 492   return rp;
 493 }
 494
 495 void adns__cancel_children(adns_query qu) {
 496   adns_query cqu, ncqu;
 497
 498   for (cqu= qu->children.head; cqu; cqu= ncqu) {
 499     ncqu= cqu->siblings.next;
 500     adns_cancel(cqu);
 501   }
 502 }
 503
 504 void adns__reset_preserved(adns_query qu) {
 505   assert(!qu->final_allocspace);
 506   adns__cancel_children(qu);
 507   qu->answer->nrrs= 0;
 508   qu->answer->rrs.untyped= 0;
 509   qu->interim_allocd= qu->preserved_allocd;
 510 }
 511
 512 static void free_query_allocs(adns_query qu) {
 513   allocnode *an, *ann;
 514
 515   adns__cancel_children(qu);
 516   for (an= qu->allocations.head; an; an= ann) { ann= an->next; free(an); }
 517   LIST_INIT(qu->allocations);
 518   adns__vbuf_free(&qu->vb);
 519   adns__vbuf_free(&qu->search_vb);
 520   free(qu->query_dgram);
 521   qu->query_dgram= 0;
 522 }
 523
 524 void adns_cancel(adns_query qu) {
 525   adns_state ads;
 526
 527   ads= qu->ads;
 528   adns__consistency(ads,qu,cc_entex);
 529   if (qu->parent) LIST_UNLINK_PART(qu->parent->children,qu,siblings.);
 530   switch (qu->state) {
 531   case query_tosend:
 532     LIST_UNLINK(ads->udpw,qu);
 533     break;
 534   case query_tcpw:
 535     LIST_UNLINK(ads->tcpw,qu);
 536     break;
 537   case query_childw:
 538     LIST_UNLINK(ads->childw,qu);
 539     break;
 540   case query_done:
 541     LIST_UNLINK(ads->output,qu);
 542     break;
 543   default:
 544     abort();
 545   }
 546   free_query_allocs(qu);
 547   free(qu->answer);
 548   free(qu);
 549   adns__consistency(ads,0,cc_entex);
 550 }
 551
 552 void adns__update_expires(adns_query qu, unsigned long ttl,
 553                           struct timeval now) {
 554   time_t max;
 555
 556   assert(ttl <= MAXTTLBELIEVE);
 557   max= now.tv_sec + ttl;
 558   if (qu->expires < max) return;
 559   qu->expires= max;
 560 }
 561
 562 static void makefinal_query(adns_query qu) {
 563   adns_answer *ans;
 564   int rrn;
 565
 566   ans= qu->answer;
 567
 568   if (qu->interim_allocd) {
 569     ans= realloc(qu->answer,
 570                  MEM_ROUND(MEM_ROUND(sizeof(*ans)) + qu->interim_allocd));
 571     if (!ans) goto x_nomem;
 572     qu->answer= ans;
 573   }
 574
 575   qu->final_allocspace= (byte*)ans + MEM_ROUND(sizeof(*ans));
 576   adns__makefinal_str(qu,&ans->cname);
 577   adns__makefinal_str(qu,&ans->owner);
 578
 579   if (ans->nrrs) {
 580     adns__makefinal_block(qu, &ans->rrs.untyped, ans->nrrs*ans->rrsz);
 581
 582     for (rrn=0; rrn<ans->nrrs; rrn++)
 583       qu->typei->makefinal(qu, ans->rrs.bytes + rrn*ans->rrsz);
 584   }
 585
 586   free_query_allocs(qu);
 587   return;
 588
 589  x_nomem:
 590   qu->preserved_allocd= 0;
 591   qu->answer->cname= 0;
 592   qu->answer->owner= 0;
 593   adns__reset_preserved(qu); /* (but we just threw away the preserved stuff) */
 594
 595   qu->answer->status= adns_s_nomemory;
 596   free_query_allocs(qu);
 597 }
 598
 599 void adns__query_done(adns_query qu) {
 600   adns_answer *ans;
 601   adns_query parent;
 602
 603   adns__cancel_children(qu);
 604
 605   qu->id= -1;
 606   ans= qu->answer;
 607
 608   if (qu->flags & adns_qf_search && ans->status != adns_s_nomemory) {
 609     if (!save_owner(qu, qu->search_vb.buf, qu->search_vb.used)) {
 610       adns__query_fail(qu,adns_s_nomemory);
 611       return;
 612     }
 613   }
 614
 615   if (ans->nrrs && qu->typei->diff_needswap) {
 616     if (!adns__vbuf_ensure(&qu->vb,ans->rrsz)) {
 617       adns__query_fail(qu,adns_s_nomemory);
 618       return;
 619     }
 620     adns__isort(ans->rrs.bytes, ans->nrrs, ans->rrsz,
 621                 qu->vb.buf,
 622                 (int(*)(void*, const void*, const void*))
 623                   qu->typei->diff_needswap,
 624                 qu->ads);
 625   }
 626   if (ans->nrrs && qu->typei->postsort) {
 627     qu->typei->postsort(qu->ads, ans->rrs.bytes, ans->nrrs, qu->typei);
 628   }
 629
 630   ans->expires= qu->expires;
 631   parent= qu->parent;
 632   if (parent) {
 633     LIST_UNLINK_PART(parent->children,qu,siblings.);
 634     LIST_UNLINK(qu->ads->childw,parent);
 635     qu->ctx.callback(parent,qu);
 636     free_query_allocs(qu);
 637     free(qu->answer);
 638     free(qu);
 639   } else {
 640     makefinal_query(qu);
 641     LIST_LINK_TAIL(qu->ads->output,qu);
 642     qu->state= query_done;
 643   }
 644 }
 645
 646 void adns__query_fail(adns_query qu, adns_status stat) {
 647   adns__reset_preserved(qu);
 648   qu->answer->status= stat;
 649   adns__query_done(qu);
 650 }
 651
 652 void adns__makefinal_str(adns_query qu, char **strp) {
 653   int l;
 654   char *before, *after;
 655
 656   before= *strp;
 657   if (!before) return;
 658   l= strlen(before)+1;
 659   after= adns__alloc_final(qu,l);
 660   memcpy(after,before,l);
 661   *strp= after;
 662 }
 663
 664 void adns__makefinal_block(adns_query qu, void **blpp, size_t sz) {
 665   void *before, *after;
 666
 667   before= *blpp;
 668   if (!before) return;
 669   after= adns__alloc_final(qu,sz);
 670   memcpy(after,before,sz);
 671   *blpp= after;
 672 }