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