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= 0;
  76   qu->answer->type= typei->type;
  77   qu->answer->expires= -1;
  78   qu->answer->nrrs= 0;
  79   qu->answer->rrs= 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   if (nextentry) {
 160     if (!adns__vbuf_append(&qu->search_vb,".",1) ||
 161         !adns__vbuf_appendstr(&qu->search_vb,nextentry)) {
 162       stat= adns_s_nomemory; goto x_fail;
 163     } else {
 164       qu->search_vb.used= qu->search_origlen;
 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 int adns_submit(adns_state ads,
 179                 const char *owner,
 180                 adns_rrtype type,
 181                 adns_queryflags flags,
 182                 void *context,
 183                 adns_query *query_r) {
 184   int r, ol, ndots;
 185   adns_status stat;
 186   const typeinfo *typei;
 187   struct timeval now;
 188   adns_query qu;
 189   const char *p;
 190
 191   typei= adns__findtype(type);
 192   if (!typei) return adns_s_unknownrrtype;
 193
 194   r= gettimeofday(&now,0); if (r) goto x_errno;
 195   qu= query_alloc(ads,typei,flags,now); if (!qu) goto x_errno;
 196
 197   qu->ctx.ext= context;
 198   qu->ctx.callback= 0;
 199   memset(&qu->ctx.info,0,sizeof(qu->ctx.info));
 200
 201   ol= strlen(owner);
 202   if (!ol) { stat= adns_s_querydomaininvalid; goto x_adnsfail; }
 203   if (ol>DNS_MAXDOMAIN+1) { stat= adns_s_querydomaintoolong; goto x_adnsfail; }
 204
 205   if (ol>=2 && owner[ol-1]=='.' && owner[ol-2]!='\\') { flags &= ~adns_qf_search; ol--; }
 206
 207   if (flags & adns_qf_search) {
 208     r= adns__vbuf_append(&qu->search_vb,owner,ol);
 209     if (!r) { stat= adns_s_nomemory; goto x_adnsfail; }
 210
 211     for (ndots=0, p=owner; (p= strchr(p,'.')); p++, ndots++);
 212     qu->search_doneabs= (ndots >= ads->searchndots) ? -1 : 0;
 213
 214     qu->search_origlen= ol;
 215
 216     adns__search_next(ads,qu,now);
 217     return 0;
 218   }
 219
 220   query_simple(ads,qu, owner,ol, typei,flags, now);
 221   return 0;
 222
 223  x_adnsfail:
 224   adns__query_fail(qu,stat);
 225   return 0;
 226
 227  x_errno:
 228   r= errno;
 229   assert(r);
 230   return r;
 231 }
 232
 233 int adns_synchronous(adns_state ads,
 234                      const char *owner,
 235                      adns_rrtype type,
 236                      adns_queryflags flags,
 237                      adns_answer **answer_r) {
 238   adns_query qu;
 239   int r;
 240
 241   r= adns_submit(ads,owner,type,flags,0,&qu);
 242   if (r) return r;
 243
 244   r= adns_wait(ads,&qu,answer_r,0);
 245   if (r) adns_cancel(qu);
 246
 247   return r;
 248 }
 249
 250 static void *alloc_common(adns_query qu, size_t sz) {
 251   allocnode *an;
 252
 253   if (!sz) return qu; /* Any old pointer will do */
 254   assert(!qu->final_allocspace);
 255   an= malloc(MEM_ROUND(MEM_ROUND(sizeof(*an)) + sz));
 256   if (!an) return 0;
 257   LIST_LINK_TAIL(qu->allocations,an);
 258   return (byte*)an + MEM_ROUND(sizeof(*an));
 259 }
 260
 261 void *adns__alloc_interim(adns_query qu, size_t sz) {
 262   sz= MEM_ROUND(sz);
 263   qu->interim_allocd += sz;
 264   return alloc_common(qu,sz);
 265 }
 266
 267 void *adns__alloc_mine(adns_query qu, size_t sz) {
 268   return alloc_common(qu,MEM_ROUND(sz));
 269 }
 270
 271 void adns__transfer_interim(adns_query from, adns_query to, void *block, size_t sz) {
 272   allocnode *an;
 273
 274   if (!block) return;
 275   an= (void*)((byte*)block - MEM_ROUND(sizeof(*an)));
 276
 277   assert(!to->final_allocspace);
 278   assert(!from->final_allocspace);
 279
 280   LIST_UNLINK(from->allocations,an);
 281   LIST_LINK_TAIL(to->allocations,an);
 282
 283   from->interim_allocd -= sz;
 284   to->interim_allocd += sz;
 285
 286   if (to->expires > from->expires) to->expires= from->expires;
 287 }
 288
 289 void *adns__alloc_final(adns_query qu, size_t sz) {
 290   /* When we're in the _final stage, we _subtract_ from interim_alloc'd
 291    * each allocation, and use final_allocspace to point to the next free
 292    * bit.
 293    */
 294   void *rp;
 295
 296   sz= MEM_ROUND(sz);
 297   rp= qu->final_allocspace;
 298   assert(rp);
 299   qu->interim_allocd -= sz;
 300   assert(qu->interim_allocd>=0);
 301   qu->final_allocspace= (byte*)rp + sz;
 302   return rp;
 303 }
 304
 305 static void cancel_children(adns_query qu) {
 306   adns_query cqu, ncqu;
 307
 308   for (cqu= qu->children.head; cqu; cqu= ncqu) {
 309     ncqu= cqu->siblings.next;
 310     adns_cancel(cqu);
 311   }
 312   LIST_INIT(qu->children);
 313 }
 314
 315 void adns__reset_cnameonly(adns_query qu) {
 316   assert(!qu->final_allocspace);
 317   cancel_children(qu);
 318   qu->answer->nrrs= 0;
 319   qu->answer->rrs= 0;
 320   qu->interim_allocd= qu->answer->cname ? MEM_ROUND(strlen(qu->answer->cname)+1) : 0;
 321 }
 322
 323 static void free_query_allocs(adns_query qu) {
 324   allocnode *an, *ann;
 325
 326   cancel_children(qu);
 327   for (an= qu->allocations.head; an; an= ann) { ann= an->next; free(an); }
 328   adns__vbuf_free(&qu->vb);
 329 }
 330
 331 void adns_cancel(adns_query qu) {
 332   switch (qu->state) {
 333   case query_udp: case query_tcpwait: case query_tcpsent:
 334     LIST_UNLINK(qu->ads->timew,qu);
 335     break;
 336   case query_child:
 337     LIST_UNLINK(qu->ads->childw,qu);
 338     break;
 339   case query_done:
 340     LIST_UNLINK(qu->ads->output,qu);
 341     break;
 342   default:
 343     abort();
 344   }
 345   free_query_allocs(qu);
 346   free(qu->answer);
 347   free(qu);
 348 }
 349
 350 void adns__update_expires(adns_query qu, unsigned long ttl, struct timeval now) {
 351   time_t max;
 352
 353   assert(ttl <= MAXTTLBELIEVE);
 354   max= now.tv_sec + ttl;
 355   if (qu->expires < max) return;
 356   qu->expires= max;
 357 }
 358
 359 static void makefinal_query(adns_query qu) {
 360   adns_answer *ans;
 361   int rrn;
 362
 363   ans= qu->answer;
 364
 365   if (qu->interim_allocd) {
 366     ans= realloc(qu->answer, MEM_ROUND(MEM_ROUND(sizeof(*ans)) + qu->interim_allocd));
 367     if (!ans) goto x_nomem;
 368     qu->answer= ans;
 369   }
 370
 371   qu->final_allocspace= (byte*)ans + MEM_ROUND(sizeof(*ans));
 372   adns__makefinal_str(qu,&ans->cname);
 373
 374   if (ans->nrrs) {
 375     adns__makefinal_block(qu, &ans->rrs.untyped, ans->nrrs*ans->rrsz);
 376
 377     for (rrn=0; rrn<ans->nrrs; rrn++)
 378       qu->typei->makefinal(qu, ans->rrs.bytes + rrn*ans->rrsz);
 379   }
 380
 381   free_query_allocs(qu);
 382   return;
 383
 384  x_nomem:
 385   qu->answer->status= adns_s_nomemory;
 386   qu->answer->cname= 0;
 387   adns__reset_cnameonly(qu);
 388   free_query_allocs(qu);
 389 }
 390
 391 void adns__query_done(adns_query qu) {
 392   adns_answer *ans;
 393   adns_query parent;
 394
 395   qu->id= -1;
 396   ans= qu->answer;
 397
 398   if (ans->nrrs && qu->typei->diff_needswap) {
 399     if (!adns__vbuf_ensure(&qu->vb,qu->typei->rrsz)) {
 400       adns__query_fail(qu,adns_s_nomemory);
 401       return;
 402     }
 403     adns__isort(ans->rrs.bytes, ans->nrrs, ans->rrsz,
 404                 qu->vb.buf,
 405                 (int(*)(void*, const void*, const void*))qu->typei->diff_needswap,
 406                 qu->ads);
 407   }
 408
 409   ans->expires= qu->expires;
 410   parent= qu->parent;
 411   if (parent) {
 412     LIST_UNLINK_PART(parent->children,qu,siblings.);
 413     qu->ctx.callback(parent,qu);
 414     free_query_allocs(qu);
 415     free(qu);
 416   } else {
 417     makefinal_query(qu);
 418     LIST_LINK_TAIL(qu->ads->output,qu);
 419   }
 420 }
 421
 422 void adns__query_fail(adns_query qu, adns_status stat) {
 423   adns__reset_cnameonly(qu);
 424   qu->answer->status= stat;
 425   adns__query_done(qu);
 426 }
 427
 428 void adns__makefinal_str(adns_query qu, char **strp) {
 429   int l;
 430   char *before, *after;
 431
 432   before= *strp;
 433   if (!before) return;
 434   l= strlen(before)+1;
 435   after= adns__alloc_final(qu,l);
 436   memcpy(after,before,l);
 437   *strp= after;
 438 }
 439
 440 void adns__makefinal_block(adns_query qu, void **blpp, size_t sz) {
 441   void *before, *after;
 442
 443   before= *blpp;
 444   if (!before) return;
 445   after= adns__alloc_final(qu,sz);
 446   memcpy(after,before,sz);
 447   *blpp= after;
 448 }