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 int adns__internal_submit(adns_state ads, adns_query *query_r,
  37                           const typeinfo *typei, vbuf *qumsg_vb, int id,
  38                           adns_queryflags flags, struct timeval now,
  39                           adns_status failstat, const qcontext *ctx) {
  40   adns_query qu;
  41
  42   qu= malloc(sizeof(*qu)); if (!qu) goto x_nomemory;
  43   qu->answer= malloc(sizeof(*qu->answer)); if (!qu->answer) goto x_freequ_nomemory;
  44
  45   qu->ads= ads;
  46   qu->state= query_udp;
  47   qu->back= qu->next= qu->parent= 0;
  48   LIST_INIT(qu->children);
  49   qu->siblings.next= qu->siblings.back= 0;
  50   LIST_INIT(qu->allocations);
  51   qu->interim_allocd= 0;
  52   qu->final_allocspace= 0;
  53
  54   qu->typei= typei;
  55   adns__vbuf_init(&qu->vb);
  56
  57   qu->cname_dgram= 0;
  58   qu->cname_dglen= qu->cname_begin= 0;
  59
  60   qu->id= id;
  61   qu->flags= flags;
  62   qu->udpretries= 0;
  63   qu->udpnextserver= 0;
  64   qu->udpsent= qu->tcpfailed= 0;
  65   timerclear(&qu->timeout);
  66   memcpy(&qu->ctx,ctx,sizeof(qu->ctx));
  67   qu->expires= now.tv_sec + MAXTTLBELIEVE;
  68
  69   qu->answer->status= adns_s_ok;
  70   qu->answer->cname= 0;
  71   qu->answer->type= typei->type;
  72   qu->answer->nrrs= 0;
  73   qu->answer->rrs= 0;
  74   qu->answer->rrsz= typei->rrsz;
  75
  76   *query_r= qu;
  77
  78   qu->query_dglen= qumsg_vb->used;
  79   if (qumsg_vb->used) {
  80     qu->query_dgram= malloc(qumsg_vb->used);
  81     if (!qu->query_dgram) {
  82       adns__query_fail(qu,adns_s_nomemory);
  83       return adns_s_ok;
  84     }
  85     memcpy(qu->query_dgram,qumsg_vb->buf,qumsg_vb->used);
  86   } else {
  87     qu->query_dgram= 0;
  88   }
  89   qu->vb= *qumsg_vb;
  90   adns__vbuf_init(qumsg_vb);
  91
  92   if (failstat) {
  93     adns__query_fail(qu,failstat);
  94     return adns_s_ok;
  95   }
  96   adns__query_udp(qu,now);
  97   adns__autosys(ads,now);
  98
  99   return adns_s_ok;
 100
 101  x_freequ_nomemory:
 102   free(qu);
 103  x_nomemory:
 104   adns__vbuf_free(qumsg_vb);
 105   return adns_s_nomemory;
 106 }
 107
 108 int adns_submit(adns_state ads,
 109                 const char *owner,
 110                 adns_rrtype type,
 111                 adns_queryflags flags,
 112                 void *context,
 113                 adns_query *query_r) {
 114   qcontext ctx;
 115   int id, r, ol;
 116   vbuf vb, search_vb;
 117   adns_status stat;
 118   const typeinfo *typei;
 119   struct timeval now;
 120
 121   typei= adns__findtype(type);
 122   if (!typei) return adns_s_unknownrrtype;
 123
 124   ctx.ext= context;
 125   ctx.callback= 0;
 126   memset(&ctx.info,0,sizeof(ctx.info));
 127
 128   r= gettimeofday(&now,0); if (r) return errno;
 129   id= 0;
 130
 131   adns__vbuf_init(&vb);
 132
 133   ol= strlen(owner);
 134   if (ol>DNS_MAXDOMAIN+1) { stat= adns_s_querydomaintoolong; goto xit; }
 135
 136   if (ol>=2 && owner[ol-1]=='.' && owner[ol-2]!='\\') { flags &= ~adns_qf_search; ol--; }
 137
 138   stat= adns__mkquery(ads,&vb,&id, owner,ol, typei,flags);
 139
 140  xit:
 141   return adns__internal_submit(ads,query_r, typei,&vb,id, flags,now, stat,&ctx);
 142 }
 143
 144 int adns_synchronous(adns_state ads,
 145                      const char *owner,
 146                      adns_rrtype type,
 147                      adns_queryflags flags,
 148                      adns_answer **answer_r) {
 149   adns_query qu;
 150   int r;
 151
 152   r= adns_submit(ads,owner,type,flags,0,&qu);
 153   if (r) return r;
 154
 155   r= adns_wait(ads,&qu,answer_r,0);
 156   if (r) adns_cancel(qu);
 157
 158   return r;
 159 }
 160
 161 static void *alloc_common(adns_query qu, size_t sz) {
 162   allocnode *an;
 163
 164   if (!sz) return qu; /* Any old pointer will do */
 165   assert(!qu->final_allocspace);
 166   an= malloc(MEM_ROUND(MEM_ROUND(sizeof(*an)) + sz));
 167   if (!an) return 0;
 168   LIST_LINK_TAIL(qu->allocations,an);
 169   return (byte*)an + MEM_ROUND(sizeof(*an));
 170 }
 171
 172 void *adns__alloc_interim(adns_query qu, size_t sz) {
 173   sz= MEM_ROUND(sz);
 174   qu->interim_allocd += sz;
 175   return alloc_common(qu,sz);
 176 }
 177
 178 void *adns__alloc_mine(adns_query qu, size_t sz) {
 179   return alloc_common(qu,MEM_ROUND(sz));
 180 }
 181
 182 void adns__transfer_interim(adns_query from, adns_query to, void *block, size_t sz) {
 183   allocnode *an;
 184
 185   if (!block) return;
 186   an= (void*)((byte*)block - MEM_ROUND(sizeof(*an)));
 187
 188   assert(!to->final_allocspace);
 189   assert(!from->final_allocspace);
 190
 191   LIST_UNLINK(from->allocations,an);
 192   LIST_LINK_TAIL(to->allocations,an);
 193
 194   from->interim_allocd -= sz;
 195   to->interim_allocd += sz;
 196
 197   if (to->expires > from->expires) to->expires= from->expires;
 198 }
 199
 200 void *adns__alloc_final(adns_query qu, size_t sz) {
 201   /* When we're in the _final stage, we _subtract_ from interim_alloc'd
 202    * each allocation, and use final_allocspace to point to the next free
 203    * bit.
 204    */
 205   void *rp;
 206
 207   sz= MEM_ROUND(sz);
 208   rp= qu->final_allocspace;
 209   assert(rp);
 210   qu->interim_allocd -= sz;
 211   assert(qu->interim_allocd>=0);
 212   qu->final_allocspace= (byte*)rp + sz;
 213   return rp;
 214 }
 215
 216 static void cancel_children(adns_query qu) {
 217   adns_query cqu, ncqu;
 218
 219   for (cqu= qu->children.head; cqu; cqu= ncqu) {
 220     ncqu= cqu->siblings.next;
 221     adns_cancel(cqu);
 222   }
 223   LIST_INIT(qu->children);
 224 }
 225
 226 void adns__reset_cnameonly(adns_query qu) {
 227   assert(!qu->final_allocspace);
 228   cancel_children(qu);
 229   qu->answer->nrrs= 0;
 230   qu->answer->rrs= 0;
 231   qu->interim_allocd= qu->answer->cname ? MEM_ROUND(strlen(qu->answer->cname)+1) : 0;
 232 }
 233
 234 static void free_query_allocs(adns_query qu) {
 235   allocnode *an, *ann;
 236
 237   cancel_children(qu);
 238   for (an= qu->allocations.head; an; an= ann) { ann= an->next; free(an); }
 239   adns__vbuf_free(&qu->vb);
 240 }
 241
 242 void adns_cancel(adns_query qu) {
 243   switch (qu->state) {
 244   case query_udp: case query_tcpwait: case query_tcpsent:
 245     LIST_UNLINK(qu->ads->timew,qu);
 246     break;
 247   case query_child:
 248     LIST_UNLINK(qu->ads->childw,qu);
 249     break;
 250   case query_done:
 251     LIST_UNLINK(qu->ads->output,qu);
 252     break;
 253   default:
 254     abort();
 255   }
 256   free_query_allocs(qu);
 257   free(qu->answer);
 258   free(qu);
 259 }
 260
 261 void adns__update_expires(adns_query qu, unsigned long ttl, struct timeval now) {
 262   time_t max;
 263
 264   assert(ttl <= MAXTTLBELIEVE);
 265   max= now.tv_sec + ttl;
 266   if (qu->expires < max) return;
 267   qu->expires= max;
 268 }
 269
 270 static void makefinal_query(adns_query qu) {
 271   adns_answer *ans;
 272   int rrn;
 273
 274   ans= qu->answer;
 275
 276   if (qu->interim_allocd) {
 277     ans= realloc(qu->answer, MEM_ROUND(MEM_ROUND(sizeof(*ans)) + qu->interim_allocd));
 278     if (!ans) goto x_nomem;
 279     qu->answer= ans;
 280   }
 281
 282   qu->final_allocspace= (byte*)ans + MEM_ROUND(sizeof(*ans));
 283   adns__makefinal_str(qu,&ans->cname);
 284
 285   if (ans->nrrs) {
 286     adns__makefinal_block(qu, &ans->rrs.untyped, ans->nrrs*ans->rrsz);
 287
 288     for (rrn=0; rrn<ans->nrrs; rrn++)
 289       qu->typei->makefinal(qu, ans->rrs.bytes + rrn*ans->rrsz);
 290   }
 291
 292   free_query_allocs(qu);
 293   return;
 294
 295  x_nomem:
 296   qu->answer->status= adns_s_nomemory;
 297   qu->answer->cname= 0;
 298   adns__reset_cnameonly(qu);
 299   free_query_allocs(qu);
 300 }
 301
 302 void adns__query_done(adns_query qu) {
 303   adns_answer *ans;
 304   adns_query parent;
 305
 306   qu->id= -1;
 307   ans= qu->answer;
 308
 309   if (ans->nrrs && qu->typei->diff_needswap) {
 310     if (!adns__vbuf_ensure(&qu->vb,qu->typei->rrsz)) {
 311       adns__query_fail(qu,adns_s_nomemory);
 312       return;
 313     }
 314     adns__isort(ans->rrs.bytes, ans->nrrs, ans->rrsz,
 315                 qu->vb.buf,
 316                 (int(*)(void*, const void*, const void*))qu->typei->diff_needswap,
 317                 qu->ads);
 318   }
 319
 320   ans->expires= qu->expires;
 321   parent= qu->parent;
 322   if (parent) {
 323     LIST_UNLINK_PART(parent->children,qu,siblings.);
 324     qu->ctx.callback(parent,qu);
 325     free_query_allocs(qu);
 326     free(qu);
 327   } else {
 328     makefinal_query(qu);
 329     LIST_LINK_TAIL(qu->ads->output,qu);
 330   }
 331 }
 332
 333 void adns__query_fail(adns_query qu, adns_status stat) {
 334   adns__reset_cnameonly(qu);
 335   qu->answer->status= stat;
 336   adns__query_done(qu);
 337 }
 338
 339 void adns__makefinal_str(adns_query qu, char **strp) {
 340   int l;
 341   char *before, *after;
 342
 343   before= *strp;
 344   if (!before) return;
 345   l= strlen(before)+1;
 346   after= adns__alloc_final(qu,l);
 347   memcpy(after,before,l);
 348   *strp= after;
 349 }
 350
 351 void adns__makefinal_block(adns_query qu, void **blpp, size_t sz) {
 352   void *before, *after;
 353
 354   before= *blpp;
 355   if (!before) return;
 356   after= adns__alloc_final(qu,sz);
 357   memcpy(after,before,sz);
 358   *blpp= after;
 359 }