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 Copyright (C) 1997-1999 Ian Jackson
   9  *
  10  *  This program is free software; you can redistribute it and/or modify
  11  *  it under the terms of the GNU General Public License as published by
  12  *  the Free Software Foundation; either version 2, or (at your option)
  13  *  any later version.
  14  *
  15  *  This program is distributed in the hope that it will be useful,
  16  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  *  GNU General Public License for more details.
  19  *
  20  *  You should have received a copy of the GNU General Public License
  21  *  along with this program; if not, write to the Free Software Foundation,
  22  *  Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  23  */
  24
  25 #include "internal.h"
  26
  27 #include <stdlib.h>
  28 #include <unistd.h>
  29 #include <errno.h>
  30 #include <string.h>
  31
  32 #include <sys/time.h>
  33
  34 #include "internal.h"
  35
  36 static adns_query query_alloc(adns_state ads, const typeinfo *typei,
  37                               adns_queryflags flags, struct timeval now) {
  38   /* Allocate a virgin query and return it. */
  39   adns_query qu;
  40
  41   qu= malloc(sizeof(*qu));  if (!qu) return 0;
  42   qu->answer= malloc(sizeof(*qu->answer));  if (!qu->answer) { free(qu); return 0; }
  43
  44   qu->ads= ads;
  45   qu->state= query_tosend;
  46   qu->back= qu->next= qu->parent= 0;
  47   LIST_INIT(qu->children);
  48   LINK_INIT(qu->siblings);
  49   LIST_INIT(qu->allocations);
  50   qu->interim_allocd= 0;
  51   qu->preserved_allocd= 0;
  52   qu->final_allocspace= 0;
  53
  54   qu->typei= typei;
  55   qu->query_dgram= 0;
  56   qu->query_dglen= 0;
  57   adns__vbuf_init(&qu->vb);
  58
  59   qu->cname_dgram= 0;
  60   qu->cname_dglen= qu->cname_begin= 0;
  61
  62   adns__vbuf_init(&qu->search_vb);
  63   qu->search_origlen= qu->search_pos= qu->search_doneabs= 0;
  64
  65   qu->id= 0;
  66   qu->flags= flags;
  67   qu->udpretries= 0;
  68   qu->udpnextserver= 0;
  69   qu->udpsent= qu->tcpfailed= 0;
  70   timerclear(&qu->timeout);
  71   qu->expires= now.tv_sec + MAXTTLBELIEVE;
  72
  73   memset(&qu->ctx,0,sizeof(qu->ctx));
  74
  75   qu->answer->status= adns_s_ok;
  76   qu->answer->cname= qu->answer->owner= 0;
  77   qu->answer->type= typei->type;
  78   qu->answer->expires= -1;
  79   qu->answer->nrrs= 0;
  80   qu->answer->rrs.untyped= 0;
  81   qu->answer->rrsz= typei->rrsz;
  82
  83   return qu;
  84 }
  85
  86 static void query_submit(adns_state ads, adns_query qu,
  87                          const typeinfo *typei, vbuf *qumsg_vb, int id,
  88                          adns_queryflags flags, struct timeval now) {
  89   /* Fills in the query message in for a previously-allocated query,
  90    * and submits it.  Cannot fail.
  91    */
  92
  93   qu->vb= *qumsg_vb;
  94   adns__vbuf_init(qumsg_vb);
  95
  96   qu->query_dgram= malloc(qu->vb.used);
  97   if (!qu->query_dgram) { adns__query_fail(qu,adns_s_nomemory); return; }
  98
  99   qu->id= id;
 100   qu->query_dglen= qu->vb.used;
 101   memcpy(qu->query_dgram,qu->vb.buf,qu->vb.used);
 102
 103   adns__query_send(qu,now);
 104   adns__autosys(ads,now);
 105 }
 106
 107 adns_status adns__internal_submit(adns_state ads, adns_query *query_r,
 108                                   const typeinfo *typei, vbuf *qumsg_vb, int id,
 109                                   adns_queryflags flags, struct timeval now,
 110                                   const qcontext *ctx) {
 111   adns_query qu;
 112
 113   qu= query_alloc(ads,typei,flags,now);
 114   if (!qu) { adns__vbuf_free(qumsg_vb); return adns_s_nomemory; }
 115   *query_r= qu;
 116
 117   memcpy(&qu->ctx,ctx,sizeof(qu->ctx));
 118   query_submit(ads,qu, typei,qumsg_vb,id,flags,now);
 119
 120   return adns_s_ok;
 121 }
 122
 123 static void query_simple(adns_state ads, adns_query qu,
 124                          const char *owner, int ol,
 125                          const typeinfo *typei, adns_queryflags flags,
 126                          struct timeval now) {
 127   vbuf vb;
 128   int id;
 129   adns_status stat;
 130
 131   adns__vbuf_init(&vb);
 132
 133   stat= adns__mkquery(ads,&vb,&id, owner,ol, typei,flags);
 134   if (stat) { adns__query_fail(qu,stat); return; }
 135
 136   query_submit(ads,qu, typei,&vb,id, flags,now);
 137 }
 138
 139 void adns__search_next(adns_state ads, adns_query qu, struct timeval now) {
 140   const char *nextentry;
 141   adns_status stat;
 142
 143   if (qu->search_doneabs<0) {
 144     nextentry= 0;
 145     qu->search_doneabs= 1;
 146   } else {
 147     if (qu->search_pos >= ads->nsearchlist) {
 148       if (qu->search_doneabs) {
 149         stat= adns_s_nxdomain; goto x_fail;
 150         return;
 151       } else {
 152         nextentry= 0;
 153         qu->search_doneabs= 1;
 154       }
 155     } else {
 156       nextentry= ads->searchlist[qu->search_pos++];
 157     }
 158   }
 159
 160   qu->search_vb.used= qu->search_origlen;
 161   if (nextentry) {
 162     if (!adns__vbuf_append(&qu->search_vb,".",1) ||
 163         !adns__vbuf_appendstr(&qu->search_vb,nextentry)) {
 164       stat= adns_s_nomemory; goto x_fail;
 165     }
 166   }
 167
 168   free(qu->query_dgram);
 169   qu->query_dgram= 0; qu->query_dglen= 0;
 170
 171   query_simple(ads,qu, qu->search_vb.buf, qu->search_vb.used, qu->typei, qu->flags, now);
 172   return;
 173
 174 x_fail:
 175   adns__query_fail(qu,stat);
 176 }
 177
 178 static int save_owner(adns_query qu, const char *owner, int ol) {
 179   /* Returns 1 if OK, otherwise there was no memory. */
 180   adns_answer *ans;
 181
 182   ans= qu->answer;
 183   assert(!ans->owner);
 184
 185   ans->owner= adns__alloc_preserved(qu,ol+1);  if (!ans->owner) return 0;
 186
 187   memcpy(ans->owner,owner,ol);
 188   ans->owner[ol]= 0;
 189   return 1;
 190 }
 191
 192 int adns_submit(adns_state ads,
 193                 const char *owner,
 194                 adns_rrtype type,
 195                 adns_queryflags flags,
 196                 void *context,
 197                 adns_query *query_r) {
 198   int r, ol, ndots;
 199   adns_status stat;
 200   const typeinfo *typei;
 201   struct timeval now;
 202   adns_query qu;
 203   const char *p;
 204
 205   typei= adns__findtype(type);
 206   if (!typei) return adns_s_unknownrrtype;
 207
 208   r= gettimeofday(&now,0); if (r) goto x_errno;
 209   qu= query_alloc(ads,typei,flags,now); if (!qu) goto x_errno;
 210
 211   qu->ctx.ext= context;
 212   qu->ctx.callback= 0;
 213   memset(&qu->ctx.info,0,sizeof(qu->ctx.info));
 214
 215   *query_r= qu;
 216
 217   ol= strlen(owner);
 218   if (!ol) { stat= adns_s_querydomaininvalid; goto x_adnsfail; }
 219   if (ol>DNS_MAXDOMAIN+1) { stat= adns_s_querydomaintoolong; goto x_adnsfail; }
 220
 221   if (ol>=1 && owner[ol-1]=='.' && (ol<2 || owner[ol-2]!='\\')) {
 222     flags &= ~adns_qf_search;
 223     ol--;
 224   }
 225
 226   if (flags & adns_qf_search) {
 227     r= adns__vbuf_append(&qu->search_vb,owner,ol);
 228     if (!r) { stat= adns_s_nomemory; goto x_adnsfail; }
 229
 230     for (ndots=0, p=owner; (p= strchr(p,'.')); p++, ndots++);
 231     qu->search_doneabs= (ndots >= ads->searchndots) ? -1 : 0;
 232     qu->search_origlen= ol;
 233     adns__search_next(ads,qu,now);
 234   } else {
 235     if (flags & adns_qf_owner) {
 236       if (!save_owner(qu,owner,ol)) { stat= adns_s_nomemory; goto x_adnsfail; }
 237     }
 238     query_simple(ads,qu, owner,ol, typei,flags, now);
 239   }
 240   return 0;
 241
 242  x_adnsfail:
 243   adns__query_fail(qu,stat);
 244   return 0;
 245
 246  x_errno:
 247   r= errno;
 248   assert(r);
 249   return r;
 250 }
 251
 252 int adns_synchronous(adns_state ads,
 253                      const char *owner,
 254                      adns_rrtype type,
 255                      adns_queryflags flags,
 256                      adns_answer **answer_r) {
 257   adns_query qu;
 258   int r;
 259
 260   r= adns_submit(ads,owner,type,flags,0,&qu);
 261   if (r) return r;
 262
 263   r= adns_wait(ads,&qu,answer_r,0);
 264   if (r) adns_cancel(qu);
 265
 266   return r;
 267 }
 268
 269 static void *alloc_common(adns_query qu, size_t sz) {
 270   allocnode *an;
 271
 272   if (!sz) return qu; /* Any old pointer will do */
 273   assert(!qu->final_allocspace);
 274   an= malloc(MEM_ROUND(MEM_ROUND(sizeof(*an)) + sz));
 275   if (!an) return 0;
 276   LIST_LINK_TAIL(qu->allocations,an);
 277   return (byte*)an + MEM_ROUND(sizeof(*an));
 278 }
 279
 280 void *adns__alloc_interim(adns_query qu, size_t sz) {
 281   void *rv;
 282
 283   sz= MEM_ROUND(sz);
 284   rv= alloc_common(qu,sz);
 285   if (!rv) return 0;
 286   qu->interim_allocd += sz;
 287   return rv;
 288 }
 289
 290 void *adns__alloc_preserved(adns_query qu, size_t sz) {
 291   void *rv;
 292
 293   sz= MEM_ROUND(sz);
 294   rv= adns__alloc_interim(qu,sz);
 295   if (!rv) return 0;
 296   qu->preserved_allocd += sz;
 297   return rv;
 298 }
 299
 300 void *adns__alloc_mine(adns_query qu, size_t sz) {
 301   return alloc_common(qu,MEM_ROUND(sz));
 302 }
 303
 304 void adns__transfer_interim(adns_query from, adns_query to, void *block, size_t sz) {
 305   allocnode *an;
 306
 307   if (!block) return;
 308   an= (void*)((byte*)block - MEM_ROUND(sizeof(*an)));
 309
 310   assert(!to->final_allocspace);
 311   assert(!from->final_allocspace);
 312
 313   LIST_UNLINK(from->allocations,an);
 314   LIST_LINK_TAIL(to->allocations,an);
 315
 316   from->interim_allocd -= sz;
 317   to->interim_allocd += sz;
 318
 319   if (to->expires > from->expires) to->expires= from->expires;
 320 }
 321
 322 void *adns__alloc_final(adns_query qu, size_t sz) {
 323   /* When we're in the _final stage, we _subtract_ from interim_alloc'd
 324    * each allocation, and use final_allocspace to point to the next free
 325    * bit.
 326    */
 327   void *rp;
 328
 329   sz= MEM_ROUND(sz);
 330   rp= qu->final_allocspace;
 331   assert(rp);
 332   qu->interim_allocd -= sz;
 333   assert(qu->interim_allocd>=0);
 334   qu->final_allocspace= (byte*)rp + sz;
 335   return rp;
 336 }
 337
 338 static void cancel_children(adns_query qu) {
 339   adns_query cqu, ncqu;
 340
 341   for (cqu= qu->children.head; cqu; cqu= ncqu) {
 342     ncqu= cqu->siblings.next;
 343     adns_cancel(cqu);
 344   }
 345   LIST_INIT(qu->children);
 346 }
 347
 348 void adns__reset_preserved(adns_query qu) {
 349   assert(!qu->final_allocspace);
 350   cancel_children(qu);
 351   qu->answer->nrrs= 0;
 352   qu->answer->rrs.untyped= 0;
 353   qu->interim_allocd= qu->preserved_allocd;
 354 }
 355
 356 static void free_query_allocs(adns_query qu) {
 357   allocnode *an, *ann;
 358
 359   cancel_children(qu);
 360   for (an= qu->allocations.head; an; an= ann) { ann= an->next; free(an); }
 361   adns__vbuf_free(&qu->vb);
 362 }
 363
 364 void adns_cancel(adns_query qu) {
 365   switch (qu->state) {
 366   case query_tosend: case query_tcpwait: case query_tcpsent:
 367     LIST_UNLINK(qu->ads->timew,qu);
 368     break;
 369   case query_child:
 370     LIST_UNLINK(qu->ads->childw,qu);
 371     break;
 372   case query_done:
 373     LIST_UNLINK(qu->ads->output,qu);
 374     break;
 375   default:
 376     abort();
 377   }
 378   free_query_allocs(qu);
 379   free(qu->answer);
 380   free(qu);
 381 }
 382
 383 void adns__update_expires(adns_query qu, unsigned long ttl, struct timeval now) {
 384   time_t max;
 385
 386   assert(ttl <= MAXTTLBELIEVE);
 387   max= now.tv_sec + ttl;
 388   if (qu->expires < max) return;
 389   qu->expires= max;
 390 }
 391
 392 static void makefinal_query(adns_query qu) {
 393   adns_answer *ans;
 394   int rrn;
 395
 396   ans= qu->answer;
 397
 398   if (qu->interim_allocd) {
 399     ans= realloc(qu->answer, MEM_ROUND(MEM_ROUND(sizeof(*ans)) + qu->interim_allocd));
 400     if (!ans) goto x_nomem;
 401     qu->answer= ans;
 402   }
 403
 404   qu->final_allocspace= (byte*)ans + MEM_ROUND(sizeof(*ans));
 405   adns__makefinal_str(qu,&ans->cname);
 406   adns__makefinal_str(qu,&ans->owner);
 407
 408   if (ans->nrrs) {
 409     adns__makefinal_block(qu, &ans->rrs.untyped, ans->nrrs*ans->rrsz);
 410
 411     for (rrn=0; rrn<ans->nrrs; rrn++)
 412       qu->typei->makefinal(qu, ans->rrs.bytes + rrn*ans->rrsz);
 413   }
 414
 415   free_query_allocs(qu);
 416   return;
 417
 418  x_nomem:
 419   qu->preserved_allocd= 0;
 420   qu->answer->cname= 0;
 421   qu->answer->owner= 0;
 422   adns__reset_preserved(qu); /* (but we just threw away the preserved stuff) */
 423
 424   qu->answer->status= adns_s_nomemory;
 425   free_query_allocs(qu);
 426 }
 427
 428 void adns__query_done(adns_query qu) {
 429   adns_answer *ans;
 430   adns_query parent;
 431
 432   cancel_children(qu);
 433
 434   qu->id= -1;
 435   ans= qu->answer;
 436
 437   if (qu->flags & adns_qf_owner && qu->flags & adns_qf_search &&
 438       ans->status != adns_s_nomemory) {
 439     if (!save_owner(qu, qu->search_vb.buf, qu->search_vb.used)) {
 440       adns__query_fail(qu,adns_s_nomemory);
 441       return;
 442     }
 443   }
 444
 445   if (ans->nrrs && qu->typei->diff_needswap) {
 446     if (!adns__vbuf_ensure(&qu->vb,qu->typei->rrsz)) {
 447       adns__query_fail(qu,adns_s_nomemory);
 448       return;
 449     }
 450     adns__isort(ans->rrs.bytes, ans->nrrs, ans->rrsz,
 451                 qu->vb.buf,
 452                 (int(*)(void*, const void*, const void*))qu->typei->diff_needswap,
 453                 qu->ads);
 454   }
 455
 456   ans->expires= qu->expires;
 457   parent= qu->parent;
 458   if (parent) {
 459     LIST_UNLINK_PART(parent->children,qu,siblings.);
 460     LIST_UNLINK(qu->ads->childw,parent);
 461     qu->ctx.callback(parent,qu);
 462     free_query_allocs(qu);
 463     free(qu);
 464   } else {
 465     makefinal_query(qu);
 466     LIST_LINK_TAIL(qu->ads->output,qu);
 467   }
 468 }
 469
 470 void adns__query_fail(adns_query qu, adns_status stat) {
 471   adns__reset_preserved(qu);
 472   qu->answer->status= stat;
 473   adns__query_done(qu);
 474 }
 475
 476 void adns__makefinal_str(adns_query qu, char **strp) {
 477   int l;
 478   char *before, *after;
 479
 480   before= *strp;
 481   if (!before) return;
 482   l= strlen(before)+1;
 483   after= adns__alloc_final(qu,l);
 484   memcpy(after,before,l);
 485   *strp= after;
 486 }
 487
 488 void adns__makefinal_block(adns_query qu, void **blpp, size_t sz) {
 489   void *before, *after;
 490
 491   before= *blpp;
 492   if (!before) return;
 493   after= adns__alloc_final(qu,sz);
 494   memcpy(after,before,sz);
 495   *blpp= after;
 496 }