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