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   adns__query_send(qu,now);
 109 }
 110
 111 adns_status adns__internal_submit(adns_state ads, adns_query *query_r,
 112                                   const typeinfo *typei, vbuf *qumsg_vb,
 113                                   int id,
 114                                   adns_queryflags flags, struct timeval now,
 115                                   const qcontext *ctx) {
 116   adns_query qu;
 117
 118   qu= query_alloc(ads,typei,typei->typekey,flags,now);
 119   if (!qu) { adns__vbuf_free(qumsg_vb); return adns_s_nomemory; }
 120   *query_r= qu;
 121
 122   memcpy(&qu->ctx,ctx,sizeof(qu->ctx));
 123   query_submit(ads,qu, typei,qumsg_vb,id,flags,now);
 124
 125   return adns_s_ok;
 126 }
 127
 128 static void query_simple(adns_state ads, adns_query qu,
 129                          const char *owner, int ol,
 130                          const typeinfo *typei, adns_queryflags flags,
 131                          struct timeval now) {
 132   vbuf vb_new;
 133   int id;
 134   adns_status stat;
 135
 136   stat= adns__mkquery(ads,&qu->vb,&id, owner,ol,
 137                       typei,qu->answer->type, flags);
 138   if (stat) {
 139     if (stat == adns_s_querydomaintoolong && (flags & adns_qf_search)) {
 140       adns__search_next(ads,qu,now);
 141       return;
 142     } else {
 143       adns__query_fail(qu,stat);
 144       return;
 145     }
 146   }
 147
 148   vb_new= qu->vb;
 149   adns__vbuf_init(&qu->vb);
 150   query_submit(ads,qu, typei,&vb_new,id, flags,now);
 151 }
 152
 153 void adns__search_next(adns_state ads, adns_query qu, struct timeval now) {
 154   const char *nextentry;
 155   adns_status stat;
 156
 157   if (qu->search_doneabs<0) {
 158     nextentry= 0;
 159     qu->search_doneabs= 1;
 160   } else {
 161     if (qu->search_pos >= ads->nsearchlist) {
 162       if (qu->search_doneabs) {
 163         qu->search_vb.used= qu->search_origlen;
 164         stat= adns_s_nxdomain; goto x_fail;
 165       } else {
 166         nextentry= 0;
 167         qu->search_doneabs= 1;
 168       }
 169     } else {
 170       nextentry= ads->searchlist[qu->search_pos++];
 171     }
 172   }
 173
 174   qu->search_vb.used= qu->search_origlen;
 175   if (nextentry) {
 176     if (!adns__vbuf_append(&qu->search_vb,".",1) ||
 177         !adns__vbuf_appendstr(&qu->search_vb,nextentry))
 178       goto x_nomemory;
 179   }
 180
 181   free(qu->query_dgram);
 182   qu->query_dgram= 0; qu->query_dglen= 0;
 183
 184   query_simple(ads,qu, qu->search_vb.buf, qu->search_vb.used,
 185                qu->typei, qu->flags, now);
 186   return;
 187
 188 x_nomemory:
 189   stat= adns_s_nomemory;
 190 x_fail:
 191   adns__query_fail(qu,stat);
 192 }
 193
 194 static int save_owner(adns_query qu, const char *owner, int ol) {
 195   /* Returns 1 if OK, otherwise there was no memory. */
 196   adns_answer *ans;
 197
 198   if (!(qu->flags & adns_qf_owner)) return 1;
 199
 200   ans= qu->answer;
 201   assert(!ans->owner);
 202
 203   ans->owner= adns__alloc_preserved(qu,ol+1);  if (!ans->owner) return 0;
 204
 205   memcpy(ans->owner,owner,ol);
 206   ans->owner[ol]= 0;
 207   return 1;
 208 }
 209
 210 int adns_submit(adns_state ads,
 211                 const char *owner,
 212                 adns_rrtype type,
 213                 adns_queryflags flags,
 214                 void *context,
 215                 adns_query *query_r) {
 216   int r, ol, ndots;
 217   adns_status stat;
 218   const typeinfo *typei;
 219   struct timeval now;
 220   adns_query qu;
 221   const char *p;
 222
 223   adns__consistency(ads,0,cc_entex);
 224
 225   typei= adns__findtype(type);
 226   if (!typei) return ENOSYS;
 227
 228   r= gettimeofday(&now,0); if (r) goto x_errno;
 229   qu= query_alloc(ads,typei,type,flags,now); if (!qu) goto x_errno;
 230
 231   qu->ctx.ext= context;
 232   qu->ctx.callback= 0;
 233   memset(&qu->ctx.info,0,sizeof(qu->ctx.info));
 234
 235   *query_r= qu;
 236
 237   ol= strlen(owner);
 238   if (!ol) { stat= adns_s_querydomaininvalid; goto x_adnsfail; }
 239   if (ol>DNS_MAXDOMAIN+1) { stat= adns_s_querydomaintoolong; goto x_adnsfail; }
 240
 241   if (ol>=1 && owner[ol-1]=='.' && (ol<2 || owner[ol-2]!='\\')) {
 242     flags &= ~adns_qf_search;
 243     qu->flags= flags;
 244     ol--;
 245   }
 246
 247   if (flags & adns_qf_search) {
 248     r= adns__vbuf_append(&qu->search_vb,owner,ol);
 249     if (!r) { stat= adns_s_nomemory; goto x_adnsfail; }
 250
 251     for (ndots=0, p=owner; (p= strchr(p,'.')); p++, ndots++);
 252     qu->search_doneabs= (ndots >= ads->searchndots) ? -1 : 0;
 253     qu->search_origlen= ol;
 254     adns__search_next(ads,qu,now);
 255   } else {
 256     if (flags & adns_qf_owner) {
 257       if (!save_owner(qu,owner,ol)) { stat= adns_s_nomemory; goto x_adnsfail; }
 258     }
 259     query_simple(ads,qu, owner,ol, typei,flags, now);
 260   }
 261   adns__autosys(ads,now);
 262   adns__consistency(ads,qu,cc_entex);
 263   return 0;
 264
 265  x_adnsfail:
 266   adns__query_fail(qu,stat);
 267   adns__consistency(ads,qu,cc_entex);
 268   return 0;
 269
 270  x_errno:
 271   r= errno;
 272   assert(r);
 273   adns__consistency(ads,0,cc_entex);
 274   return r;
 275 }
 276
 277 int adns_submit_reverse_any(adns_state ads,
 278                             const struct sockaddr *addr,
 279                             const char *zone,
 280                             adns_rrtype type,
 281                             adns_queryflags flags,
 282                             void *context,
 283                             adns_query *query_r) {
 284   const unsigned char *iaddr;
 285   char *buf, *buf_free;
 286   char shortbuf[100];
 287   int r, lreq;
 288
 289   flags &= ~adns_qf_search;
 290
 291   if (addr->sa_family != AF_INET) return ENOSYS;
 292   iaddr= (const unsigned char*)
 293     &(((const struct sockaddr_in*)addr) -> sin_addr);
 294
 295   lreq= strlen(zone) + 4*4 + 1;
 296   if (lreq > sizeof(shortbuf)) {
 297     buf= malloc(strlen(zone) + 4*4 + 1);
 298     if (!buf) return errno;
 299     buf_free= buf;
 300   } else {
 301     buf= shortbuf;
 302     buf_free= 0;
 303   }
 304   sprintf(buf, "%d.%d.%d.%d.%s", iaddr[3], iaddr[2], iaddr[1], iaddr[0], zone);
 305
 306   r= adns_submit(ads,buf,type,flags,context,query_r);
 307   free(buf_free);
 308   return r;
 309 }
 310
 311 int adns_submit_reverse(adns_state ads,
 312                         const struct sockaddr *addr,
 313                         adns_rrtype type,
 314                         adns_queryflags flags,
 315                         void *context,
 316                         adns_query *query_r) {
 317   if (type != adns_r_ptr && type != adns_r_ptr_raw) return EINVAL;
 318   return adns_submit_reverse_any(ads,addr,"in-addr.arpa",
 319                                  type,flags,context,query_r);
 320 }
 321
 322 int adns_synchronous(adns_state ads,
 323                      const char *owner,
 324                      adns_rrtype type,
 325                      adns_queryflags flags,
 326                      adns_answer **answer_r) {
 327   adns_query qu;
 328   int r;
 329
 330   r= adns_submit(ads,owner,type,flags,0,&qu);
 331   if (r) return r;
 332
 333   r= adns_wait(ads,&qu,answer_r,0);
 334   if (r) adns_cancel(qu);
 335
 336   return r;
 337 }
 338
 339 static void *alloc_common(adns_query qu, size_t sz) {
 340   allocnode *an;
 341
 342   if (!sz) return qu; /* Any old pointer will do */
 343   assert(!qu->final_allocspace);
 344   an= malloc(MEM_ROUND(MEM_ROUND(sizeof(*an)) + sz));
 345   if (!an) return 0;
 346   LIST_LINK_TAIL(qu->allocations,an);
 347   return (byte*)an + MEM_ROUND(sizeof(*an));
 348 }
 349
 350 void *adns__alloc_interim(adns_query qu, size_t sz) {
 351   void *rv;
 352
 353   sz= MEM_ROUND(sz);
 354   rv= alloc_common(qu,sz);
 355   if (!rv) return 0;
 356   qu->interim_allocd += sz;
 357   return rv;
 358 }
 359
 360 void *adns__alloc_preserved(adns_query qu, size_t sz) {
 361   void *rv;
 362
 363   sz= MEM_ROUND(sz);
 364   rv= adns__alloc_interim(qu,sz);
 365   if (!rv) return 0;
 366   qu->preserved_allocd += sz;
 367   return rv;
 368 }
 369
 370 void *adns__alloc_mine(adns_query qu, size_t sz) {
 371   return alloc_common(qu,MEM_ROUND(sz));
 372 }
 373
 374 void adns__transfer_interim(adns_query from, adns_query to,
 375                             void *block, size_t sz) {
 376   allocnode *an;
 377
 378   if (!block) return;
 379   an= (void*)((byte*)block - MEM_ROUND(sizeof(*an)));
 380
 381   assert(!to->final_allocspace);
 382   assert(!from->final_allocspace);
 383
 384   LIST_UNLINK(from->allocations,an);
 385   LIST_LINK_TAIL(to->allocations,an);
 386
 387   sz= MEM_ROUND(sz);
 388   from->interim_allocd -= sz;
 389   to->interim_allocd += sz;
 390
 391   if (to->expires > from->expires) to->expires= from->expires;
 392 }
 393
 394 void *adns__alloc_final(adns_query qu, size_t sz) {
 395   /* When we're in the _final stage, we _subtract_ from interim_alloc'd
 396    * each allocation, and use final_allocspace to point to the next free
 397    * bit.
 398    */
 399   void *rp;
 400
 401   sz= MEM_ROUND(sz);
 402   rp= qu->final_allocspace;
 403   assert(rp);
 404   qu->interim_allocd -= sz;
 405   assert(qu->interim_allocd>=0);
 406   qu->final_allocspace= (byte*)rp + sz;
 407   return rp;
 408 }
 409
 410 static void cancel_children(adns_query qu) {
 411   adns_query cqu, ncqu;
 412
 413   for (cqu= qu->children.head; cqu; cqu= ncqu) {
 414     ncqu= cqu->siblings.next;
 415     adns_cancel(cqu);
 416   }
 417 }
 418
 419 void adns__reset_preserved(adns_query qu) {
 420   assert(!qu->final_allocspace);
 421   cancel_children(qu);
 422   qu->answer->nrrs= 0;
 423   qu->answer->rrs.untyped= 0;
 424   qu->interim_allocd= qu->preserved_allocd;
 425 }
 426
 427 static void free_query_allocs(adns_query qu) {
 428   allocnode *an, *ann;
 429
 430   cancel_children(qu);
 431   for (an= qu->allocations.head; an; an= ann) { ann= an->next; free(an); }
 432   LIST_INIT(qu->allocations);
 433   adns__vbuf_free(&qu->vb);
 434   adns__vbuf_free(&qu->search_vb);
 435   free(qu->query_dgram);
 436   qu->query_dgram= 0;
 437 }
 438
 439 void adns_cancel(adns_query qu) {
 440   adns_state ads;
 441
 442   ads= qu->ads;
 443   adns__consistency(ads,qu,cc_entex);
 444   if (qu->parent) LIST_UNLINK_PART(qu->parent->children,qu,siblings.);
 445   switch (qu->state) {
 446   case query_tosend:
 447     LIST_UNLINK(ads->udpw,qu);
 448     break;
 449   case query_tcpw:
 450     LIST_UNLINK(ads->tcpw,qu);
 451     break;
 452   case query_childw:
 453     LIST_UNLINK(ads->childw,qu);
 454     break;
 455   case query_done:
 456     LIST_UNLINK(ads->output,qu);
 457     break;
 458   default:
 459     abort();
 460   }
 461   free_query_allocs(qu);
 462   free(qu->answer);
 463   free(qu);
 464   adns__consistency(ads,0,cc_entex);
 465 }
 466
 467 void adns__update_expires(adns_query qu, unsigned long ttl,
 468                           struct timeval now) {
 469   time_t max;
 470
 471   assert(ttl <= MAXTTLBELIEVE);
 472   max= now.tv_sec + ttl;
 473   if (qu->expires < max) return;
 474   qu->expires= max;
 475 }
 476
 477 static void makefinal_query(adns_query qu) {
 478   adns_answer *ans;
 479   int rrn;
 480
 481   ans= qu->answer;
 482
 483   if (qu->interim_allocd) {
 484     ans= realloc(qu->answer,
 485                  MEM_ROUND(MEM_ROUND(sizeof(*ans)) + qu->interim_allocd));
 486     if (!ans) goto x_nomem;
 487     qu->answer= ans;
 488   }
 489
 490   qu->final_allocspace= (byte*)ans + MEM_ROUND(sizeof(*ans));
 491   adns__makefinal_str(qu,&ans->cname);
 492   adns__makefinal_str(qu,&ans->owner);
 493
 494   if (ans->nrrs) {
 495     adns__makefinal_block(qu, &ans->rrs.untyped, ans->nrrs*ans->rrsz);
 496
 497     for (rrn=0; rrn<ans->nrrs; rrn++)
 498       qu->typei->makefinal(qu, ans->rrs.bytes + rrn*ans->rrsz);
 499   }
 500
 501   free_query_allocs(qu);
 502   return;
 503
 504  x_nomem:
 505   qu->preserved_allocd= 0;
 506   qu->answer->cname= 0;
 507   qu->answer->owner= 0;
 508   adns__reset_preserved(qu); /* (but we just threw away the preserved stuff) */
 509
 510   qu->answer->status= adns_s_nomemory;
 511   free_query_allocs(qu);
 512 }
 513
 514 void adns__query_done(adns_query qu) {
 515   adns_answer *ans;
 516   adns_query parent;
 517
 518   cancel_children(qu);
 519
 520   qu->id= -1;
 521   ans= qu->answer;
 522
 523   if (qu->flags & adns_qf_search && ans->status != adns_s_nomemory) {
 524     if (!save_owner(qu, qu->search_vb.buf, qu->search_vb.used)) {
 525       adns__query_fail(qu,adns_s_nomemory);
 526       return;
 527     }
 528   }
 529
 530   if (ans->nrrs && qu->typei->diff_needswap) {
 531     if (!adns__vbuf_ensure(&qu->vb,qu->typei->rrsz)) {
 532       adns__query_fail(qu,adns_s_nomemory);
 533       return;
 534     }
 535     adns__isort(ans->rrs.bytes, ans->nrrs, ans->rrsz,
 536                 qu->vb.buf,
 537                 (int(*)(void*, const void*, const void*))
 538                   qu->typei->diff_needswap,
 539                 qu->ads);
 540   }
 541   if (ans->nrrs && qu->typei->postsort) {
 542     qu->typei->postsort(qu->ads, ans->rrs.bytes, ans->nrrs, qu->typei);
 543   }
 544
 545   ans->expires= qu->expires;
 546   parent= qu->parent;
 547   if (parent) {
 548     LIST_UNLINK_PART(parent->children,qu,siblings.);
 549     LIST_UNLINK(qu->ads->childw,parent);
 550     qu->ctx.callback(parent,qu);
 551     free_query_allocs(qu);
 552     free(qu->answer);
 553     free(qu);
 554   } else {
 555     makefinal_query(qu);
 556     LIST_LINK_TAIL(qu->ads->output,qu);
 557     qu->state= query_done;
 558   }
 559 }
 560
 561 void adns__query_fail(adns_query qu, adns_status stat) {
 562   adns__reset_preserved(qu);
 563   qu->answer->status= stat;
 564   adns__query_done(qu);
 565 }
 566
 567 void adns__makefinal_str(adns_query qu, char **strp) {
 568   int l;
 569   char *before, *after;
 570
 571   before= *strp;
 572   if (!before) return;
 573   l= strlen(before)+1;
 574   after= adns__alloc_final(qu,l);
 575   memcpy(after,before,l);
 576   *strp= after;
 577 }
 578
 579 void adns__makefinal_block(adns_query qu, void **blpp, size_t sz) {
 580   void *before, *after;
 581
 582   before= *blpp;
 583   if (!before) return;
 584   after= adns__alloc_final(qu,sz);
 585   memcpy(after,before,sz);
 586   *blpp= after;
 587 }