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) 1997-2000,2003,2006,2014  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 3, 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  */
  27
  28 #include "internal.h"
  29
  30 #include <stdlib.h>
  31 #include <unistd.h>
  32 #include <errno.h>
  33
  34 #include <sys/time.h>
  35
  36 #include "internal.h"
  37
  38 static adns_query query_alloc(adns_state ads,
  39                               const typeinfo *typei, adns_rrtype type,
  40                               adns_queryflags flags, struct timeval now) {
  41   /* Allocate a virgin query and return it. */
  42   adns_query qu;
  43
  44   qu= malloc(sizeof(*qu));  if (!qu) return 0;
  45   qu->answer= malloc(sizeof(*qu->answer));
  46   if (!qu->answer) { free(qu); return 0; }
  47
  48   qu->ads= ads;
  49   qu->state= query_tosend;
  50   qu->back= qu->next= qu->parent= 0;
  51   LIST_INIT(qu->children);
  52   LINK_INIT(qu->siblings);
  53   LIST_INIT(qu->allocations);
  54   qu->interim_allocd= 0;
  55   qu->preserved_allocd= 0;
  56   qu->final_allocspace= 0;
  57
  58   qu->typei= typei;
  59   qu->query_dgram= 0;
  60   qu->query_dglen= 0;
  61   adns__vbuf_init(&qu->vb);
  62
  63   qu->cname_dgram= 0;
  64   qu->cname_dglen= qu->cname_begin= 0;
  65
  66   adns__vbuf_init(&qu->search_vb);
  67   qu->search_origlen= qu->search_pos= qu->search_doneabs= 0;
  68
  69   qu->id= -2; /* will be overwritten with real id before we leave adns */
  70   qu->flags= flags;
  71   qu->retries= 0;
  72   qu->udpnextserver= 0;
  73   qu->udpsent= 0;
  74   timerclear(&qu->timeout);
  75   qu->expires= now.tv_sec + MAXTTLBELIEVE;
  76
  77   memset(&qu->ctx,0,sizeof(qu->ctx));
  78
  79   qu->answer->status= adns_s_ok;
  80   qu->answer->cname= qu->answer->owner= 0;
  81   qu->answer->type= type;
  82   qu->answer->expires= -1;
  83   qu->answer->nrrs= 0;
  84   qu->answer->rrs.untyped= 0;
  85   qu->answer->rrsz= typei->getrrsz(typei,type);
  86
  87   return qu;
  88 }
  89
  90 static void query_submit(adns_state ads, adns_query qu,
  91                          const typeinfo *typei, vbuf *qumsg_vb, int id,
  92                          adns_queryflags flags, struct timeval now) {
  93   /* Fills in the query message in for a previously-allocated query,
  94    * and submits it.  Cannot fail.  Takes over the memory for qumsg_vb.
  95    */
  96
  97   qu->vb= *qumsg_vb;
  98   adns__vbuf_init(qumsg_vb);
  99
 100   qu->query_dgram= malloc(qu->vb.used);
 101   if (!qu->query_dgram) { adns__query_fail(qu,adns_s_nomemory); return; }
 102
 103   qu->id= id;
 104   qu->query_dglen= qu->vb.used;
 105   memcpy(qu->query_dgram,qu->vb.buf,qu->vb.used);
 106
 107   typei->query_send(qu,now);
 108 }
 109
 110 adns_status adns__ckl_hostname(adns_state ads, adns_queryflags flags,
 111                                union checklabel_state *cls,
 112                                qcontext *ctx, int labnum,
 113                                const char *dgram, int labstart, int lablen)
 114 {
 115   int i, c;
 116   const char *label = dgram+labstart;
 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 st;
 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     st= adns__findlabel_next(&fls, &lablen,&labstart);
 142     assert(!st); assert(lablen >= 0);
 143     st= typei->checklabel(ads,flags, &cls,ctx,
 144                            labnum++, dgram,labstart,lablen);
 145     if (st) return st;
 146   } while (lablen);
 147   return adns_s_ok;
 148 }
 149
 150 adns_status adns__internal_submit(adns_state ads, adns_query *query_r,
 151                                   adns_query parent,
 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 st;
 158
 159   st= check_domain_name(ads, flags,ctx,typei, qumsg_vb->buf,qumsg_vb->used);
 160   if (st) goto x_err;
 161   qu= query_alloc(ads,typei,type,flags,now);
 162   if (!qu) { st = adns_s_nomemory; goto x_err; }
 163   *query_r= qu;
 164
 165   qu->parent= parent;
 166   LIST_LINK_TAIL_PART(parent->children,qu,siblings.);
 167   memcpy(&qu->ctx,ctx,sizeof(qu->ctx));
 168   query_submit(ads,qu, typei,qumsg_vb,id,flags,now);
 169
 170   return adns_s_ok;
 171
 172 x_err:
 173   adns__vbuf_free(qumsg_vb);
 174   return st;
 175 }
 176
 177 static void query_simple(adns_state ads, adns_query qu,
 178                          const char *owner, int ol,
 179                          const typeinfo *typei, adns_queryflags flags,
 180                          struct timeval now) {
 181   vbuf vb_new;
 182   int id;
 183   adns_status st;
 184
 185   st= adns__mkquery(ads,&qu->vb,&id, owner,ol,
 186                       typei,qu->answer->type, flags);
 187   if (st) {
 188     if (st == adns_s_querydomaintoolong && (flags & adns_qf_search)) {
 189       adns__search_next(ads,qu,now);
 190       return;
 191     } else {
 192       adns__query_fail(qu,st);
 193       return;
 194     }
 195   }
 196
 197   st= check_domain_name(ads, flags,&qu->ctx,typei, qu->vb.buf,qu->vb.used);
 198   if (st) { adns__query_fail(qu,st); return; }
 199
 200   vb_new= qu->vb;
 201   adns__vbuf_init(&qu->vb);
 202   query_submit(ads,qu, typei,&vb_new,id, flags,now);
 203 }
 204
 205 void adns__search_next(adns_state ads, adns_query qu, struct timeval now) {
 206   const char *nextentry;
 207   adns_status st;
 208
 209   if (qu->search_doneabs<0) {
 210     nextentry= 0;
 211     qu->search_doneabs= 1;
 212   } else {
 213     if (qu->search_pos >= ads->nsearchlist) {
 214       if (qu->search_doneabs) {
 215         qu->search_vb.used= qu->search_origlen;
 216         st= adns_s_nxdomain; goto x_fail;
 217       } else {
 218         nextentry= 0;
 219         qu->search_doneabs= 1;
 220       }
 221     } else {
 222       nextentry= ads->searchlist[qu->search_pos++];
 223     }
 224   }
 225
 226   qu->search_vb.used= qu->search_origlen;
 227   if (nextentry) {
 228     if (!adns__vbuf_append(&qu->search_vb,".",1) ||
 229         !adns__vbuf_appendstr(&qu->search_vb,nextentry))
 230       goto x_nomemory;
 231   }
 232
 233   free(qu->query_dgram);
 234   qu->query_dgram= 0; qu->query_dglen= 0;
 235
 236   query_simple(ads,qu, qu->search_vb.buf, qu->search_vb.used,
 237                qu->typei, qu->flags, now);
 238   return;
 239
 240 x_nomemory:
 241   st= adns_s_nomemory;
 242 x_fail:
 243   adns__query_fail(qu,st);
 244 }
 245
 246 static int save_owner(adns_query qu, const char *owner, int ol) {
 247   /* Returns 1 if OK, otherwise there was no memory. */
 248   adns_answer *ans;
 249
 250   if (!(qu->flags & adns_qf_owner)) return 1;
 251
 252   ans= qu->answer;
 253   assert(!ans->owner);
 254
 255   ans->owner= adns__alloc_preserved(qu,ol+1);  if (!ans->owner) return 0;
 256
 257   memcpy(ans->owner,owner,ol);
 258   ans->owner[ol]= 0;
 259   return 1;
 260 }
 261
 262 int adns_submit(adns_state ads,
 263                 const char *owner,
 264                 adns_rrtype type,
 265                 adns_queryflags flags,
 266                 void *context,
 267                 adns_query *query_r) {
 268   int r, ol, ndots;
 269   adns_status st;
 270   const typeinfo *typei;
 271   struct timeval now;
 272   adns_query qu;
 273   const char *p;
 274
 275   adns__consistency(ads,0,cc_entex);
 276
 277   typei= adns__findtype(type);
 278   if (!typei) return ENOSYS;
 279
 280   r= gettimeofday(&now,0); if (r) goto x_errno;
 281   qu= query_alloc(ads,typei,type,flags,now); if (!qu) goto x_errno;
 282
 283   qu->ctx.ext= context;
 284   qu->ctx.callback= 0;
 285   memset(&qu->ctx.pinfo,0,sizeof(qu->ctx.pinfo));
 286   memset(&qu->ctx.tinfo,0,sizeof(qu->ctx.tinfo));
 287
 288   *query_r= qu;
 289
 290   ol= strlen(owner);
 291   if (!ol) { st= adns_s_querydomaininvalid; goto x_adnsfail; }
 292   if (ol>DNS_MAXDOMAIN+1) { st= adns_s_querydomaintoolong; goto x_adnsfail; }
 293
 294   if (ol>=1 && owner[ol-1]=='.' && (ol<2 || owner[ol-2]!='\\')) {
 295     flags &= ~adns_qf_search;
 296     qu->flags= flags;
 297     ol--;
 298   }
 299
 300   if (flags & adns_qf_search) {
 301     r= adns__vbuf_append(&qu->search_vb,owner,ol);
 302     if (!r) { st= adns_s_nomemory; goto x_adnsfail; }
 303
 304     for (ndots=0, p=owner; (p= strchr(p,'.')); p++, ndots++);
 305     qu->search_doneabs= (ndots >= ads->searchndots) ? -1 : 0;
 306     qu->search_origlen= ol;
 307     adns__search_next(ads,qu,now);
 308   } else {
 309     if (flags & adns_qf_owner) {
 310       if (!save_owner(qu,owner,ol)) { st= adns_s_nomemory; goto x_adnsfail; }
 311     }
 312     query_simple(ads,qu, owner,ol, typei,flags, now);
 313   }
 314   adns__autosys(ads,now);
 315   adns__returning(ads,qu);
 316   return 0;
 317
 318  x_adnsfail:
 319   adns__query_fail(qu,st);
 320   adns__returning(ads,qu);
 321   return 0;
 322
 323  x_errno:
 324   r= errno;
 325   assert(r);
 326   adns__returning(ads,0);
 327   return r;
 328 }
 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 = 0;
 338   char shortbuf[100];
 339   int r;
 340
 341   flags &= ~adns_qf_search;
 342
 343   buf = shortbuf;
 344   r= adns__make_reverse_domain(addr,zone, &buf,sizeof(shortbuf),&buf_free);
 345   if (r) return r;
 346   r= adns_submit(ads,buf,type,flags,context,query_r);
 347   free(buf_free);
 348   return r;
 349 }
 350
 351 int adns_submit_reverse(adns_state ads,
 352                         const struct sockaddr *addr,
 353                         adns_rrtype type,
 354                         adns_queryflags flags,
 355                         void *context,
 356                         adns_query *query_r) {
 357   if (((type^adns_r_ptr) & adns_rrt_reprmask) &&
 358       ((type^adns_r_ptr_raw) & adns_rrt_reprmask))
 359     return EINVAL;
 360   return adns_submit_reverse_any(ads,addr,0,type,flags,context,query_r);
 361 }
 362
 363 int adns_synchronous(adns_state ads,
 364                      const char *owner,
 365                      adns_rrtype type,
 366                      adns_queryflags flags,
 367                      adns_answer **answer_r) {
 368   adns_query qu;
 369   int r;
 370
 371   r= adns_submit(ads,owner,type,flags,0,&qu);
 372   if (r) return r;
 373
 374   r= adns_wait(ads,&qu,answer_r,0);
 375   if (r) adns_cancel(qu);
 376
 377   return r;
 378 }
 379
 380 static void *alloc_common(adns_query qu, size_t sz) {
 381   allocnode *an;
 382
 383   if (!sz) return qu; /* Any old pointer will do */
 384   assert(!qu->final_allocspace);
 385   an= malloc(MEM_ROUND(MEM_ROUND(sizeof(*an)) + sz));
 386   if (!an) return 0;
 387   LIST_LINK_TAIL(qu->allocations,an);
 388   an->sz= sz;
 389   return (byte*)an + MEM_ROUND(sizeof(*an));
 390 }
 391
 392 void *adns__alloc_interim(adns_query qu, size_t sz) {
 393   void *rv;
 394
 395   sz= MEM_ROUND(sz);
 396   rv= alloc_common(qu,sz);
 397   if (!rv) return 0;
 398   qu->interim_allocd += sz;
 399   return rv;
 400 }
 401
 402 void *adns__alloc_preserved(adns_query qu, size_t sz) {
 403   void *rv;
 404
 405   sz= MEM_ROUND(sz);
 406   rv= adns__alloc_interim(qu,sz);
 407   if (!rv) return 0;
 408   qu->preserved_allocd += sz;
 409   return rv;
 410 }
 411
 412 static allocnode *alloc__info(adns_query qu, void *p, size_t *sz_r) {
 413   allocnode *an;
 414
 415   if (!p || p == qu) { *sz_r= 0; return 0; }
 416   an= (allocnode *)((byte *)p - MEM_ROUND(sizeof(allocnode)));
 417   *sz_r= MEM_ROUND(an->sz);
 418   return an;
 419 }
 420
 421 void adns__free_interim(adns_query qu, void *p) {
 422   size_t sz;
 423   allocnode *an= alloc__info(qu, p, &sz);
 424
 425   if (!an) return;
 426   assert(!qu->final_allocspace);
 427   LIST_UNLINK(qu->allocations, an);
 428   free(an);
 429   qu->interim_allocd -= sz;
 430   assert(!qu->interim_allocd >= 0);
 431 }
 432
 433 void *adns__alloc_mine(adns_query qu, size_t sz) {
 434   return alloc_common(qu,MEM_ROUND(sz));
 435 }
 436
 437 void adns__transfer_interim(adns_query from, adns_query to, void *block) {
 438   size_t sz;
 439   allocnode *an= alloc__info(from, block, &sz);
 440
 441   if (!an) return;
 442
 443   assert(!to->final_allocspace);
 444   assert(!from->final_allocspace);
 445
 446   LIST_UNLINK(from->allocations,an);
 447   LIST_LINK_TAIL(to->allocations,an);
 448
 449   from->interim_allocd -= sz;
 450   to->interim_allocd += sz;
 451
 452   if (to->expires > from->expires) to->expires= from->expires;
 453 }
 454
 455 void *adns__alloc_final(adns_query qu, size_t sz) {
 456   /* When we're in the _final stage, we _subtract_ from interim_alloc'd
 457    * each allocation, and use final_allocspace to point to the next free
 458    * bit.
 459    */
 460   void *rp;
 461
 462   sz= MEM_ROUND(sz);
 463   rp= qu->final_allocspace;
 464   assert(rp);
 465   qu->interim_allocd -= sz;
 466   assert(qu->interim_allocd>=0);
 467   qu->final_allocspace= (byte*)rp + sz;
 468   return rp;
 469 }
 470
 471 void adns__cancel_children(adns_query qu) {
 472   adns_query cqu, ncqu;
 473
 474   for (cqu= qu->children.head; cqu; cqu= ncqu) {
 475     ncqu= cqu->siblings.next;
 476     adns__cancel(cqu);
 477   }
 478 }
 479
 480 void adns__reset_preserved(adns_query qu) {
 481   assert(!qu->final_allocspace);
 482   adns__cancel_children(qu);
 483   qu->answer->nrrs= 0;
 484   qu->answer->rrs.untyped= 0;
 485   qu->interim_allocd= qu->preserved_allocd;
 486 }
 487
 488 static void free_query_allocs(adns_query qu) {
 489   allocnode *an, *ann;
 490
 491   adns__cancel_children(qu);
 492   for (an= qu->allocations.head; an; an= ann) { ann= an->next; free(an); }
 493   LIST_INIT(qu->allocations);
 494   adns__vbuf_free(&qu->vb);
 495   adns__vbuf_free(&qu->search_vb);
 496   free(qu->query_dgram);
 497   qu->query_dgram= 0;
 498 }
 499
 500 void adns__returning(adns_state ads, adns_query qu_for_caller) {
 501   while (ads->intdone.head) {
 502     adns_query iq= ads->intdone.head;
 503     adns_query parent= iq->parent;
 504     LIST_UNLINK_PART(parent->children,iq,siblings.);
 505     LIST_UNLINK(iq->ads->childw,parent);
 506     LIST_UNLINK(ads->intdone,iq);
 507     iq->ctx.callback(parent,iq);
 508     free_query_allocs(iq);
 509     free(iq->answer);
 510     free(iq);
 511   }
 512   adns__consistency(ads,qu_for_caller,cc_entex);
 513 }
 514
 515 void adns__cancel(adns_query qu) {
 516   adns_state ads;
 517
 518   ads= qu->ads;
 519   adns__consistency(ads,qu,cc_freq);
 520   if (qu->parent) LIST_UNLINK_PART(qu->parent->children,qu,siblings.);
 521   switch (qu->state) {
 522   case query_tosend:
 523     LIST_UNLINK(ads->udpw,qu);
 524     break;
 525   case query_tcpw:
 526     LIST_UNLINK(ads->tcpw,qu);
 527     break;
 528   case query_childw:
 529     LIST_UNLINK(ads->childw,qu);
 530     break;
 531   case query_done:
 532     if (qu->parent)
 533       LIST_UNLINK(ads->intdone,qu);
 534     else
 535       LIST_UNLINK(ads->output,qu);
 536     break;
 537   default:
 538     abort();
 539   }
 540   free_query_allocs(qu);
 541   free(qu->answer);
 542   free(qu);
 543 }
 544
 545 void adns_cancel(adns_query qu) {
 546   adns_state ads;
 547
 548   assert(!qu->parent);
 549   ads= qu->ads;
 550   adns__consistency(ads,qu,cc_entex);
 551   adns__cancel(qu);
 552   adns__returning(ads,0);
 553 }
 554
 555 void adns__update_expires(adns_query qu, unsigned long ttl,
 556                           struct timeval now) {
 557   time_t max;
 558
 559   assert(ttl <= MAXTTLBELIEVE);
 560   max= now.tv_sec + ttl;
 561   if (qu->expires < max) return;
 562   qu->expires= max;
 563 }
 564
 565 static void makefinal_query(adns_query qu) {
 566   adns_answer *ans;
 567   int rrn;
 568
 569   ans= qu->answer;
 570
 571   if (qu->interim_allocd) {
 572     ans= realloc(qu->answer,
 573                  MEM_ROUND(MEM_ROUND(sizeof(*ans)) + qu->interim_allocd));
 574     if (!ans) goto x_nomem;
 575     qu->answer= ans;
 576   }
 577
 578   qu->final_allocspace= (byte*)ans + MEM_ROUND(sizeof(*ans));
 579   adns__makefinal_str(qu,&ans->cname);
 580   adns__makefinal_str(qu,&ans->owner);
 581
 582   if (ans->nrrs) {
 583     adns__makefinal_block(qu, &ans->rrs.untyped, ans->nrrs*ans->rrsz);
 584
 585     for (rrn=0; rrn<ans->nrrs; rrn++)
 586       qu->typei->makefinal(qu, ans->rrs.bytes + rrn*ans->rrsz);
 587   }
 588
 589   free_query_allocs(qu);
 590   return;
 591
 592  x_nomem:
 593   qu->preserved_allocd= 0;
 594   qu->answer->cname= 0;
 595   qu->answer->owner= 0;
 596   adns__reset_preserved(qu); /* (but we just threw away the preserved stuff) */
 597
 598   qu->answer->status= adns_s_nomemory;
 599   free_query_allocs(qu);
 600 }
 601
 602 void adns__query_done(adns_query qu) {
 603   adns_state ads=qu->ads;
 604   adns_answer *ans;
 605
 606   adns__cancel_children(qu);
 607
 608   qu->id= -1;
 609   ans= qu->answer;
 610
 611   if (qu->flags & adns_qf_search && ans->status != adns_s_nomemory) {
 612     if (!save_owner(qu, qu->search_vb.buf, qu->search_vb.used)) {
 613       adns__query_fail(qu,adns_s_nomemory);
 614       return;
 615     }
 616   }
 617
 618   if (ans->nrrs && qu->typei->diff_needswap) {
 619     if (!adns__vbuf_ensure(&qu->vb,qu->answer->rrsz)) {
 620       adns__query_fail(qu,adns_s_nomemory);
 621       return;
 622     }
 623     adns__isort(ans->rrs.bytes, ans->nrrs, ans->rrsz,
 624                 qu->vb.buf,
 625                 (int(*)(void*, const void*, const void*))
 626                   qu->typei->diff_needswap,
 627                 qu->ads);
 628   }
 629   if (ans->nrrs && qu->typei->postsort) {
 630     qu->typei->postsort(qu->ads, ans->rrs.bytes,
 631                         ans->nrrs,ans->rrsz, qu->typei);
 632   }
 633
 634   ans->expires= qu->expires;
 635   qu->state= query_done;
 636   if (qu->parent) {
 637     LIST_LINK_TAIL(ads->intdone,qu);
 638   } else {
 639     makefinal_query(qu);
 640     LIST_LINK_TAIL(qu->ads->output,qu);
 641   }
 642 }
 643
 644 void adns__query_fail(adns_query qu, adns_status st) {
 645   adns__reset_preserved(qu);
 646   qu->answer->status= st;
 647   adns__query_done(qu);
 648 }
 649
 650 void adns__makefinal_str(adns_query qu, char **strp) {
 651   int l;
 652   char *before, *after;
 653
 654   before= *strp;
 655   if (!before) return;
 656   l= strlen(before)+1;
 657   after= adns__alloc_final(qu,l);
 658   memcpy(after,before,l);
 659   *strp= after;
 660 }
 661
 662 void adns__makefinal_block(adns_query qu, void **blpp, size_t sz) {
 663   void *before, *after;
 664
 665   before= *blpp;
 666   if (!before) return;
 667   after= adns__alloc_final(qu,sz);
 668   memcpy(after,before,sz);
 669   *blpp= after;
 670 }