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) 1997-2000,2003,2006,2014-2016  Ian Jackson
  10  *    Copyright (C) 2014  Mark Wooding
  11  *    Copyright (C) 1999-2000,2003,2006  Tony Finch
  12  *    Copyright (C) 1991 Massachusetts Institute of Technology
  13  *  (See the file INSTALL for full details.)
  14  *
  15  *  This program is free software; you can redistribute it and/or modify
  16  *  it under the terms of the GNU General Public License as published by
  17  *  the Free Software Foundation; either version 3, or (at your option)
  18  *  any later version.
  19  *
  20  *  This program is distributed in the hope that it will be useful,
  21  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  22  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  23  *  GNU General Public License for more details.
  24  *
  25  *  You should have received a copy of the GNU General Public License
  26  *  along with this program; if not, write to the Free Software Foundation.
  27  */
  28
  29 #include "internal.h"
  30
  31 #include <stdlib.h>
  32 #include <unistd.h>
  33 #include <errno.h>
  34
  35 #include <sys/time.h>
  36
  37 #include "internal.h"
  38
  39 static adns_query query_alloc(adns_state ads,
  40                               const typeinfo *typei, adns_rrtype type,
  41                               adns_queryflags flags, struct timeval now) {
  42   /* Allocate a virgin query and return it. */
  43   adns_query qu;
  44
  45   qu= malloc(sizeof(*qu));  if (!qu) return 0;
  46   qu->answer= malloc(sizeof(*qu->answer));
  47   if (!qu->answer) { free(qu); return 0; }
  48
  49   qu->ads= ads;
  50   qu->state= query_tosend;
  51   qu->back= qu->next= qu->parent= 0;
  52   LIST_INIT(qu->children);
  53   LINK_INIT(qu->siblings);
  54   LIST_INIT(qu->allocations);
  55   qu->interim_allocd= 0;
  56   qu->preserved_allocd= 0;
  57   qu->final_allocspace= 0;
  58
  59   qu->typei= typei;
  60   qu->query_dgram= 0;
  61   qu->query_dglen= 0;
  62   adns__vbuf_init(&qu->vb);
  63
  64   qu->cname_dgram= 0;
  65   qu->cname_dglen= qu->cname_begin= 0;
  66
  67   adns__vbuf_init(&qu->search_vb);
  68   qu->search_origlen= qu->search_pos= qu->search_doneabs= 0;
  69
  70   qu->id= -2; /* will be overwritten with real id before we leave adns */
  71   qu->flags= flags;
  72   qu->retries= 0;
  73   qu->udpnextserver= 0;
  74   qu->udpsent= 0;
  75   timerclear(&qu->timeout);
  76   qu->expires= now.tv_sec + MAXTTLBELIEVE;
  77
  78   memset(&qu->ctx,0,sizeof(qu->ctx));
  79
  80   qu->answer->status= adns_s_ok;
  81   qu->answer->cname= qu->answer->owner= 0;
  82   qu->answer->type= type;
  83   qu->answer->expires= -1;
  84   qu->answer->nrrs= 0;
  85   qu->answer->rrs.untyped= 0;
  86   qu->answer->rrsz= typei->getrrsz(typei,type);
  87
  88   return qu;
  89 }
  90
  91 static void query_submit(adns_state ads, adns_query qu,
  92                          const typeinfo *typei, vbuf *qumsg_vb, int id,
  93                          adns_queryflags flags, struct timeval now) {
  94   /* Fills in the query message in for a previously-allocated query,
  95    * and submits it.  Cannot fail.  Takes over the memory for qumsg_vb.
  96    */
  97
  98   qu->vb= *qumsg_vb;
  99   adns__vbuf_init(qumsg_vb);
 100
 101   qu->query_dgram= malloc(qu->vb.used);
 102   if (!qu->query_dgram) { adns__query_fail(qu,adns_s_nomemory); return; }
 103
 104   qu->id= id;
 105   qu->query_dglen= qu->vb.used;
 106   memcpy(qu->query_dgram,qu->vb.buf,qu->vb.used);
 107
 108   typei->query_send(qu,now);
 109 }
 110
 111 adns_status adns__ckl_hostname(adns_state ads, adns_queryflags flags,
 112                                union checklabel_state *cls,
 113                                qcontext *ctx, int labnum,
 114                                const char *dgram, int labstart, int lablen)
 115 {
 116   int i, c;
 117   const char *label = dgram+labstart;
 118
 119   if (flags & adns_qf_quoteok_query) return adns_s_ok;
 120   for (i=0; i<lablen; i++) {
 121     c= label[i];
 122     if (c == '-') {
 123       if (!i) return adns_s_querydomaininvalid;
 124     } else if (!ctype_alpha(c) && !ctype_digit(c)) {
 125       return adns_s_querydomaininvalid;
 126     }
 127   }
 128   return adns_s_ok;
 129 }
 130
 131 static adns_status check_domain_name(adns_state ads, adns_queryflags flags,
 132                                      qcontext *ctx, const typeinfo *typei,
 133                                      const byte *dgram, int dglen)
 134 {
 135   findlabel_state fls;
 136   adns_status st;
 137   int labnum= 0, labstart, lablen;
 138   union checklabel_state cls;
 139
 140   adns__findlabel_start(&fls,ads, -1,0, dgram,dglen,dglen, DNS_HDRSIZE,0);
 141   do {
 142     st= adns__findlabel_next(&fls, &lablen,&labstart);
 143     assert(!st); assert(lablen >= 0);
 144     st= typei->checklabel(ads,flags, &cls,ctx,
 145                            labnum++, dgram,labstart,lablen);
 146     if (st) return st;
 147   } while (lablen);
 148   return adns_s_ok;
 149 }
 150
 151 adns_status adns__internal_submit(adns_state ads, adns_query *query_r,
 152                                   adns_query parent,
 153                                   const typeinfo *typei, adns_rrtype type,
 154                                   vbuf *qumsg_vb, int id,
 155                                   adns_queryflags flags, struct timeval now,
 156                                   qcontext *ctx) {
 157   adns_query qu;
 158   adns_status st;
 159
 160   st= check_domain_name(ads, flags,ctx,typei, qumsg_vb->buf,qumsg_vb->used);
 161   if (st) goto x_err;
 162   qu= query_alloc(ads,typei,type,flags,now);
 163   if (!qu) { st = adns_s_nomemory; goto x_err; }
 164   *query_r= qu;
 165
 166   qu->parent= parent;
 167   LIST_LINK_TAIL_PART(parent->children,qu,siblings.);
 168   memcpy(&qu->ctx,ctx,sizeof(qu->ctx));
 169   query_submit(ads,qu, typei,qumsg_vb,id,flags,now);
 170
 171   return adns_s_ok;
 172
 173 x_err:
 174   adns__vbuf_free(qumsg_vb);
 175   return st;
 176 }
 177
 178 static void query_simple(adns_state ads, adns_query qu,
 179                          const char *owner, int ol,
 180                          const typeinfo *typei, adns_queryflags flags,
 181                          struct timeval now) {
 182   vbuf vb_new;
 183   int id;
 184   adns_status st;
 185
 186   st= adns__mkquery(ads,&qu->vb,&id, owner,ol,
 187                       typei,qu->answer->type, flags);
 188   if (st) {
 189     if (st == adns_s_querydomaintoolong && (flags & adns_qf_search)) {
 190       adns__search_next(ads,qu,now);
 191       return;
 192     } else {
 193       adns__query_fail(qu,st);
 194       return;
 195     }
 196   }
 197
 198   st= check_domain_name(ads, flags,&qu->ctx,typei, qu->vb.buf,qu->vb.used);
 199   if (st) { adns__query_fail(qu,st); return; }
 200
 201   vb_new= qu->vb;
 202   adns__vbuf_init(&qu->vb);
 203   query_submit(ads,qu, typei,&vb_new,id, flags,now);
 204 }
 205
 206 void adns__search_next(adns_state ads, adns_query qu, struct timeval now) {
 207   const char *nextentry;
 208   adns_status st;
 209
 210   if (qu->search_doneabs<0) {
 211     nextentry= 0;
 212     qu->search_doneabs= 1;
 213   } else {
 214     if (qu->search_pos >= ads->nsearchlist) {
 215       if (qu->search_doneabs) {
 216         qu->search_vb.used= qu->search_origlen;
 217         st= adns_s_nxdomain; goto x_fail;
 218       } else {
 219         nextentry= 0;
 220         qu->search_doneabs= 1;
 221       }
 222     } else {
 223       nextentry= ads->searchlist[qu->search_pos++];
 224     }
 225   }
 226
 227   qu->search_vb.used= qu->search_origlen;
 228   if (nextentry) {
 229     if (!adns__vbuf_append(&qu->search_vb,".",1) ||
 230         !adns__vbuf_appendstr(&qu->search_vb,nextentry))
 231       goto x_nomemory;
 232   }
 233
 234   free(qu->query_dgram);
 235   qu->query_dgram= 0; qu->query_dglen= 0;
 236
 237   query_simple(ads,qu, qu->search_vb.buf, qu->search_vb.used,
 238                qu->typei, qu->flags, now);
 239   return;
 240
 241 x_nomemory:
 242   st= adns_s_nomemory;
 243 x_fail:
 244   adns__query_fail(qu,st);
 245 }
 246
 247 static int save_owner(adns_query qu, const char *owner, int ol) {
 248   /* Returns 1 if OK, otherwise there was no memory. */
 249   adns_answer *ans;
 250
 251   if (!(qu->flags & adns_qf_owner)) return 1;
 252
 253   ans= qu->answer;
 254   assert(!ans->owner);
 255
 256   ans->owner= adns__alloc_preserved(qu,ol+1);  if (!ans->owner) return 0;
 257
 258   memcpy(ans->owner,owner,ol);
 259   ans->owner[ol]= 0;
 260   return 1;
 261 }
 262
 263 int adns_submit(adns_state ads,
 264                 const char *owner,
 265                 adns_rrtype type,
 266                 adns_queryflags flags,
 267                 void *context,
 268                 adns_query *query_r) {
 269   int r, ol, ndots;
 270   adns_status st;
 271   const typeinfo *typei;
 272   struct timeval now;
 273   adns_query qu;
 274   const char *p;
 275
 276   adns__consistency(ads,0,cc_entex);
 277
 278   if (flags & ~(adns_queryflags)0x4009ffff)
 279     /* 0x40080000 are reserved for `harmless' future expansion
 280      * 0x00000020 used to be adns_qf_quoteok_cname, now the default;
 281      * see also addrfam.c:textaddr_check_qf */
 282     return ENOSYS;
 283
 284   typei= adns__findtype(type);
 285   if (!typei) return ENOSYS;
 286
 287   r= gettimeofday(&now,0); if (r) goto x_errno;
 288   qu= query_alloc(ads,typei,type,flags,now); if (!qu) goto x_errno;
 289
 290   qu->ctx.ext= context;
 291   qu->ctx.callback= 0;
 292   memset(&qu->ctx.pinfo,0,sizeof(qu->ctx.pinfo));
 293   memset(&qu->ctx.tinfo,0,sizeof(qu->ctx.tinfo));
 294
 295   *query_r= qu;
 296
 297   ol= strlen(owner);
 298   if (!ol) { st= adns_s_querydomaininvalid; goto x_adnsfail; }
 299   if (ol>DNS_MAXDOMAIN+1) { st= adns_s_querydomaintoolong; goto x_adnsfail; }
 300
 301   if (ol>=1 && owner[ol-1]=='.' && (ol<2 || owner[ol-2]!='\\')) {
 302     flags &= ~adns_qf_search;
 303     qu->flags= flags;
 304     ol--;
 305   }
 306
 307   if (flags & adns_qf_search) {
 308     r= adns__vbuf_append(&qu->search_vb,owner,ol);
 309     if (!r) { st= adns_s_nomemory; goto x_adnsfail; }
 310
 311     for (ndots=0, p=owner; (p= strchr(p,'.')); p++, ndots++);
 312     qu->search_doneabs= (ndots >= ads->searchndots) ? -1 : 0;
 313     qu->search_origlen= ol;
 314     adns__search_next(ads,qu,now);
 315   } else {
 316     if (flags & adns_qf_owner) {
 317       if (!save_owner(qu,owner,ol)) { st= adns_s_nomemory; goto x_adnsfail; }
 318     }
 319     query_simple(ads,qu, owner,ol, typei,flags, now);
 320   }
 321   adns__autosys(ads,now);
 322   adns__returning(ads,qu);
 323   return 0;
 324
 325  x_adnsfail:
 326   adns__query_fail(qu,st);
 327   adns__returning(ads,qu);
 328   return 0;
 329
 330  x_errno:
 331   r= errno;
 332   assert(r);
 333   adns__returning(ads,0);
 334   return r;
 335 }
 336
 337 int adns_submit_reverse_any(adns_state ads,
 338                             const struct sockaddr *addr,
 339                             const char *zone,
 340                             adns_rrtype type,
 341                             adns_queryflags flags,
 342                             void *context,
 343                             adns_query *query_r) {
 344   char *buf, *buf_free = 0;
 345   char shortbuf[100];
 346   int r;
 347
 348   flags &= ~adns_qf_search;
 349
 350   buf = shortbuf;
 351   r= adns__make_reverse_domain(addr,zone, &buf,sizeof(shortbuf),&buf_free);
 352   if (r) return r;
 353   r= adns_submit(ads,buf,type,flags,context,query_r);
 354   free(buf_free);
 355   return r;
 356 }
 357
 358 int adns_submit_reverse(adns_state ads,
 359                         const struct sockaddr *addr,
 360                         adns_rrtype type,
 361                         adns_queryflags flags,
 362                         void *context,
 363                         adns_query *query_r) {
 364   if (((type^adns_r_ptr) & adns_rrt_reprmask) &&
 365       ((type^adns_r_ptr_raw) & adns_rrt_reprmask))
 366     return EINVAL;
 367   return adns_submit_reverse_any(ads,addr,0,type,flags,context,query_r);
 368 }
 369
 370 int adns_synchronous(adns_state ads,
 371                      const char *owner,
 372                      adns_rrtype type,
 373                      adns_queryflags flags,
 374                      adns_answer **answer_r) {
 375   adns_query qu;
 376   int r;
 377
 378   r= adns_submit(ads,owner,type,flags,0,&qu);
 379   if (r) return r;
 380
 381   r= adns_wait(ads,&qu,answer_r,0);
 382   if (r) adns_cancel(qu);
 383
 384   return r;
 385 }
 386
 387 static void *alloc_common(adns_query qu, size_t sz) {
 388   allocnode *an;
 389
 390   if (!sz) return qu; /* Any old pointer will do */
 391   assert(!qu->final_allocspace);
 392   an= malloc(MEM_ROUND(MEM_ROUND(sizeof(*an)) + sz));
 393   if (!an) return 0;
 394   LIST_LINK_TAIL(qu->allocations,an);
 395   an->sz= sz;
 396   return (byte*)an + MEM_ROUND(sizeof(*an));
 397 }
 398
 399 void *adns__alloc_interim(adns_query qu, size_t sz) {
 400   void *rv;
 401
 402   sz= MEM_ROUND(sz);
 403   rv= alloc_common(qu,sz);
 404   if (!rv) return 0;
 405   qu->interim_allocd += sz;
 406   return rv;
 407 }
 408
 409 void *adns__alloc_preserved(adns_query qu, size_t sz) {
 410   void *rv;
 411
 412   sz= MEM_ROUND(sz);
 413   rv= adns__alloc_interim(qu,sz);
 414   if (!rv) return 0;
 415   qu->preserved_allocd += sz;
 416   return rv;
 417 }
 418
 419 static allocnode *alloc__info(adns_query qu, void *p, size_t *sz_r) {
 420   allocnode *an;
 421
 422   if (!p || p == qu) { *sz_r= 0; return 0; }
 423   an= (allocnode *)((byte *)p - MEM_ROUND(sizeof(allocnode)));
 424   *sz_r= MEM_ROUND(an->sz);
 425   return an;
 426 }
 427
 428 void adns__free_interim(adns_query qu, void *p) {
 429   size_t sz;
 430   allocnode *an= alloc__info(qu, p, &sz);
 431
 432   if (!an) return;
 433   assert(!qu->final_allocspace);
 434   LIST_UNLINK(qu->allocations, an);
 435   free(an);
 436   qu->interim_allocd -= sz;
 437   assert(!qu->interim_allocd >= 0);
 438 }
 439
 440 void *adns__alloc_mine(adns_query qu, size_t sz) {
 441   return alloc_common(qu,MEM_ROUND(sz));
 442 }
 443
 444 void adns__transfer_interim(adns_query from, adns_query to, void *block) {
 445   size_t sz;
 446   allocnode *an= alloc__info(from, block, &sz);
 447
 448   if (!an) return;
 449
 450   assert(!to->final_allocspace);
 451   assert(!from->final_allocspace);
 452
 453   LIST_UNLINK(from->allocations,an);
 454   LIST_LINK_TAIL(to->allocations,an);
 455
 456   from->interim_allocd -= sz;
 457   to->interim_allocd += sz;
 458
 459   if (to->expires > from->expires) to->expires= from->expires;
 460 }
 461
 462 void *adns__alloc_final(adns_query qu, size_t sz) {
 463   /* When we're in the _final stage, we _subtract_ from interim_alloc'd
 464    * each allocation, and use final_allocspace to point to the next free
 465    * bit.
 466    */
 467   void *rp;
 468
 469   sz= MEM_ROUND(sz);
 470   rp= qu->final_allocspace;
 471   assert(rp);
 472   qu->interim_allocd -= sz;
 473   assert(qu->interim_allocd>=0);
 474   qu->final_allocspace= (byte*)rp + sz;
 475   return rp;
 476 }
 477
 478 void adns__cancel_children(adns_query qu) {
 479   adns_query cqu, ncqu;
 480
 481   for (cqu= qu->children.head; cqu; cqu= ncqu) {
 482     ncqu= cqu->siblings.next;
 483     adns__cancel(cqu);
 484   }
 485 }
 486
 487 void adns__reset_preserved(adns_query qu) {
 488   assert(!qu->final_allocspace);
 489   adns__cancel_children(qu);
 490   qu->answer->nrrs= 0;
 491   qu->answer->rrs.untyped= 0;
 492   qu->interim_allocd= qu->preserved_allocd;
 493 }
 494
 495 static void free_query_allocs(adns_query qu) {
 496   allocnode *an, *ann;
 497
 498   adns__cancel_children(qu);
 499   for (an= qu->allocations.head; an; an= ann) { ann= an->next; free(an); }
 500   LIST_INIT(qu->allocations);
 501   adns__vbuf_free(&qu->vb);
 502   adns__vbuf_free(&qu->search_vb);
 503   free(qu->query_dgram);
 504   qu->query_dgram= 0;
 505 }
 506
 507 void adns__returning(adns_state ads, adns_query qu_for_caller) {
 508   while (ads->intdone.head) {
 509     adns_query iq= ads->intdone.head;
 510     adns_query parent= iq->parent;
 511     LIST_UNLINK_PART(parent->children,iq,siblings.);
 512     LIST_UNLINK(iq->ads->childw,parent);
 513     LIST_UNLINK(ads->intdone,iq);
 514     iq->ctx.callback(parent,iq);
 515     free_query_allocs(iq);
 516     free(iq->answer);
 517     free(iq);
 518   }
 519   adns__consistency(ads,qu_for_caller,cc_entex);
 520 }
 521
 522 void adns__cancel(adns_query qu) {
 523   adns_state ads;
 524
 525   ads= qu->ads;
 526   adns__consistency(ads,qu,cc_freq);
 527   if (qu->parent) LIST_UNLINK_PART(qu->parent->children,qu,siblings.);
 528   switch (qu->state) {
 529   case query_tosend:
 530     LIST_UNLINK(ads->udpw,qu);
 531     break;
 532   case query_tcpw:
 533     LIST_UNLINK(ads->tcpw,qu);
 534     break;
 535   case query_childw:
 536     LIST_UNLINK(ads->childw,qu);
 537     break;
 538   case query_done:
 539     if (qu->parent)
 540       LIST_UNLINK(ads->intdone,qu);
 541     else
 542       LIST_UNLINK(ads->output,qu);
 543     break;
 544   default:
 545     abort();
 546   }
 547   free_query_allocs(qu);
 548   free(qu->answer);
 549   free(qu);
 550 }
 551
 552 void adns_cancel(adns_query qu) {
 553   adns_state ads;
 554
 555   assert(!qu->parent);
 556   ads= qu->ads;
 557   adns__consistency(ads,qu,cc_entex);
 558   adns__cancel(qu);
 559   adns__returning(ads,0);
 560 }
 561
 562 void adns__update_expires(adns_query qu, unsigned long ttl,
 563                           struct timeval now) {
 564   time_t max;
 565
 566   assert(ttl <= MAXTTLBELIEVE);
 567   max= now.tv_sec + ttl;
 568   if (qu->expires < max) return;
 569   qu->expires= max;
 570 }
 571
 572 static void makefinal_query(adns_query qu) {
 573   adns_answer *ans;
 574   int rrn;
 575
 576   ans= qu->answer;
 577
 578   if (qu->interim_allocd) {
 579     ans= realloc(qu->answer,
 580                  MEM_ROUND(MEM_ROUND(sizeof(*ans)) + qu->interim_allocd));
 581     if (!ans) goto x_nomem;
 582     qu->answer= ans;
 583   }
 584
 585   qu->final_allocspace= (byte*)ans + MEM_ROUND(sizeof(*ans));
 586   adns__makefinal_str(qu,&ans->cname);
 587   adns__makefinal_str(qu,&ans->owner);
 588
 589   if (ans->nrrs) {
 590     adns__makefinal_block(qu, &ans->rrs.untyped, ans->nrrs*ans->rrsz);
 591
 592     for (rrn=0; rrn<ans->nrrs; rrn++)
 593       qu->typei->makefinal(qu, ans->rrs.bytes + rrn*ans->rrsz);
 594   }
 595
 596   free_query_allocs(qu);
 597   return;
 598
 599  x_nomem:
 600   qu->preserved_allocd= 0;
 601   qu->answer->cname= 0;
 602   qu->answer->owner= 0;
 603   adns__reset_preserved(qu); /* (but we just threw away the preserved stuff) */
 604
 605   qu->answer->status= adns_s_nomemory;
 606   free_query_allocs(qu);
 607 }
 608
 609 void adns__query_done(adns_query qu) {
 610   adns_state ads=qu->ads;
 611   adns_answer *ans;
 612
 613   adns__cancel_children(qu);
 614
 615   qu->id= -1;
 616   ans= qu->answer;
 617
 618   if (qu->flags & adns_qf_search && ans->status != adns_s_nomemory) {
 619     if (!save_owner(qu, qu->search_vb.buf, qu->search_vb.used)) {
 620       adns__query_fail(qu,adns_s_nomemory);
 621       return;
 622     }
 623   }
 624
 625   if (ans->nrrs && qu->typei->diff_needswap) {
 626     if (!adns__vbuf_ensure(&qu->vb,qu->answer->rrsz)) {
 627       adns__query_fail(qu,adns_s_nomemory);
 628       return;
 629     }
 630     adns__isort(ans->rrs.bytes, ans->nrrs, ans->rrsz,
 631                 qu->vb.buf,
 632                 (int(*)(void*, const void*, const void*))
 633                   qu->typei->diff_needswap,
 634                 qu->ads);
 635   }
 636   if (ans->nrrs && qu->typei->postsort) {
 637     qu->typei->postsort(qu->ads, ans->rrs.bytes,
 638                         ans->nrrs,ans->rrsz, qu->typei);
 639   }
 640
 641   ans->expires= qu->expires;
 642   qu->state= query_done;
 643   if (qu->parent) {
 644     LIST_LINK_TAIL(ads->intdone,qu);
 645   } else {
 646     makefinal_query(qu);
 647     LIST_LINK_TAIL(qu->ads->output,qu);
 648   }
 649 }
 650
 651 void adns__query_fail(adns_query qu, adns_status st) {
 652   adns__reset_preserved(qu);
 653   qu->answer->status= st;
 654   adns__query_done(qu);
 655 }
 656
 657 void adns__makefinal_str(adns_query qu, char **strp) {
 658   int l;
 659   char *before, *after;
 660
 661   before= *strp;
 662   if (!before) return;
 663   l= strlen(before)+1;
 664   after= adns__alloc_final(qu,l);
 665   memcpy(after,before,l);
 666   *strp= after;
 667 }
 668
 669 void adns__makefinal_block(adns_query qu, void **blpp, size_t sz) {
 670   void *before, *after;
 671
 672   before= *blpp;
 673   if (!before) return;
 674   after= adns__alloc_final(qu,sz);
 675   memcpy(after,before,sz);
 676   *blpp= after;
 677 }