mdw@git.distorted.org.uk Git - adns/blob - src/setup.c

   1 /*
   2  * setup.c
   3  * - configuration file parsing
   4  * - management of global state
   5  */
   6 /*
   7  *  This file is
   8  *    Copyright (C) 1997-1999 Ian Jackson <ian@davenant.greenend.org.uk>
   9  *
  10  *  It is part of adns, which is
  11  *    Copyright (C) 1997-2000 Ian Jackson <ian@davenant.greenend.org.uk>
  12  *    Copyright (C) 1999-2000 Tony Finch <dot@dotat.at>
  13  *
  14  *  This program is free software; you can redistribute it and/or modify
  15  *  it under the terms of the GNU General Public License as published by
  16  *  the Free Software Foundation; either version 2, or (at your option)
  17  *  any later version.
  18  *
  19  *  This program is distributed in the hope that it will be useful,
  20  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  *  GNU General Public License for more details.
  23  *
  24  *  You should have received a copy of the GNU General Public License
  25  *  along with this program; if not, write to the Free Software Foundation,
  26  *  Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  27  */
  28
  29 #include <stdlib.h>
  30 #include <errno.h>
  31 #include <limits.h>
  32 #include <unistd.h>
  33 #include <fcntl.h>
  34
  35 #include <sys/types.h>
  36 #include <netdb.h>
  37 #include <sys/socket.h>
  38 #include <netinet/in.h>
  39 #include <arpa/inet.h>
  40
  41 #include "internal.h"
  42
  43 static void readconfig(adns_state ads, const char *filename, int warnmissing);
  44
  45 static void addserver(adns_state ads, struct in_addr addr) {
  46   int i;
  47   struct server *ss;
  48
  49   for (i=0; i<ads->nservers; i++) {
  50     if (ads->servers[i].addr.s_addr == addr.s_addr) {
  51       adns__debug(ads,-1,0,"duplicate nameserver %s ignored",inet_ntoa(addr));
  52       return;
  53     }
  54   }
  55
  56   if (ads->nservers>=MAXSERVERS) {
  57     adns__diag(ads,-1,0,"too many nameservers, ignoring %s",inet_ntoa(addr));
  58     return;
  59   }
  60
  61   ss= ads->servers+ads->nservers;
  62   ss->addr= addr;
  63   ads->nservers++;
  64 }
  65
  66 static void freesearchlist(adns_state ads) {
  67   if (ads->nsearchlist) free(*ads->searchlist);
  68   free(ads->searchlist);
  69 }
  70
  71 static void saveerr(adns_state ads, int en) {
  72   if (!ads->configerrno) ads->configerrno= en;
  73 }
  74
  75 static void configparseerr(adns_state ads, const char *fn, int lno,
  76                            const char *fmt, ...) {
  77   va_list al;
  78
  79   saveerr(ads,EINVAL);
  80   if (!ads->diagfile || (ads->iflags & adns_if_noerrprint)) return;
  81
  82   if (lno==-1) fprintf(ads->diagfile,"adns: %s: ",fn);
  83   else fprintf(ads->diagfile,"adns: %s:%d: ",fn,lno);
  84   va_start(al,fmt);
  85   vfprintf(ads->diagfile,fmt,al);
  86   va_end(al);
  87   fputc('\n',ads->diagfile);
  88 }
  89
  90 static int nextword(const char **bufp_io, const char **word_r, int *l_r) {
  91   const char *p, *q;
  92
  93   p= *bufp_io;
  94   while (ctype_whitespace(*p)) p++;
  95   if (!*p) return 0;
  96
  97   q= p;
  98   while (*q && !ctype_whitespace(*q)) q++;
  99
 100   *l_r= q-p;
 101   *word_r= p;
 102   *bufp_io= q;
 103
 104   return 1;
 105 }
 106
 107 static void ccf_nameserver(adns_state ads, const char *fn, int lno, const char *buf) {
 108   struct in_addr ia;
 109
 110   if (!inet_aton(buf,&ia)) {
 111     configparseerr(ads,fn,lno,"invalid nameserver address `%s'",buf);
 112     return;
 113   }
 114   adns__debug(ads,-1,0,"using nameserver %s",inet_ntoa(ia));
 115   addserver(ads,ia);
 116 }
 117
 118 static void ccf_search(adns_state ads, const char *fn, int lno, const char *buf) {
 119   const char *bufp, *word;
 120   char *newchars, **newptrs, **pp;
 121   int count, tl, l;
 122
 123   if (!buf) return;
 124
 125   bufp= buf;
 126   count= 0;
 127   tl= 0;
 128   while (nextword(&bufp,&word,&l)) { count++; tl += l+1; }
 129
 130   newptrs= malloc(sizeof(char*)*count);  if (!newptrs) { saveerr(ads,errno); return; }
 131   newchars= malloc(tl);  if (!newchars) { saveerr(ads,errno); free(newptrs); return; }
 132
 133   bufp= buf;
 134   pp= newptrs;
 135   while (nextword(&bufp,&word,&l)) {
 136     *pp++= newchars;
 137     memcpy(newchars,word,l);
 138     newchars += l;
 139     *newchars++ = 0;
 140   }
 141
 142   freesearchlist(ads);
 143   ads->nsearchlist= count;
 144   ads->searchlist= newptrs;
 145 }
 146
 147 static void ccf_sortlist(adns_state ads, const char *fn, int lno, const char *buf) {
 148   const char *word;
 149   char tbuf[200], *slash, *ep;
 150   struct in_addr base, mask;
 151   int l;
 152   unsigned long initial, baselocal;
 153
 154   if (!buf) return;
 155
 156   ads->nsortlist= 0;
 157   while (nextword(&buf,&word,&l)) {
 158     if (ads->nsortlist >= MAXSORTLIST) {
 159       adns__diag(ads,-1,0,"too many sortlist entries, ignoring %.*s onwards",l,word);
 160       return;
 161     }
 162
 163     if (l >= sizeof(tbuf)) {
 164       configparseerr(ads,fn,lno,"sortlist entry `%.*s' too long",l,word);
 165       continue;
 166     }
 167
 168     memcpy(tbuf,word,l); tbuf[l]= 0;
 169     slash= strchr(tbuf,'/');
 170     if (slash) *slash++= 0;
 171
 172     if (!inet_aton(tbuf,&base)) {
 173       configparseerr(ads,fn,lno,"invalid address `%s' in sortlist",tbuf);
 174       continue;
 175     }
 176
 177     if (slash) {
 178       if (strchr(slash,'.')) {
 179         if (!inet_aton(slash,&mask)) {
 180           configparseerr(ads,fn,lno,"invalid mask `%s' in sortlist",slash);
 181           continue;
 182         }
 183         if (base.s_addr & ~mask.s_addr) {
 184           configparseerr(ads,fn,lno,
 185                          "mask `%s' in sortlist overlaps address `%s'",slash,tbuf);
 186           continue;
 187         }
 188       } else {
 189         initial= strtoul(slash,&ep,10);
 190         if (*ep || initial>32) {
 191           configparseerr(ads,fn,lno,"mask length `%s' invalid",slash);
 192           continue;
 193         }
 194         mask.s_addr= htonl((0x0ffffffffUL) << (32-initial));
 195       }
 196     } else {
 197       baselocal= ntohl(base.s_addr);
 198       if (!baselocal & 0x080000000UL) /* class A */
 199         mask.s_addr= htonl(0x0ff000000UL);
 200       else if ((baselocal & 0x0c0000000UL) == 0x080000000UL)
 201         mask.s_addr= htonl(0x0ffff0000UL); /* class B */
 202       else if ((baselocal & 0x0f0000000UL) == 0x0e0000000UL)
 203         mask.s_addr= htonl(0x0ff000000UL); /* class C */
 204       else {
 205         configparseerr(ads,fn,lno,
 206                        "network address `%s' in sortlist is not in classed ranges,"
 207                        " must specify mask explicitly", tbuf);
 208         continue;
 209       }
 210     }
 211
 212     ads->sortlist[ads->nsortlist].base= base;
 213     ads->sortlist[ads->nsortlist].mask= mask;
 214     ads->nsortlist++;
 215   }
 216 }
 217
 218 static void ccf_options(adns_state ads, const char *fn, int lno, const char *buf) {
 219   const char *word;
 220   char *ep;
 221   unsigned long v;
 222   int l;
 223
 224   if (!buf) return;
 225
 226   while (nextword(&buf,&word,&l)) {
 227     if (l==5 && !memcmp(word,"debug",5)) {
 228       ads->iflags |= adns_if_debug;
 229       continue;
 230     }
 231     if (l>=6 && !memcmp(word,"ndots:",6)) {
 232       v= strtoul(word+6,&ep,10);
 233       if (l==6 || ep != word+l || v > INT_MAX) {
 234         configparseerr(ads,fn,lno,"option `%.*s' malformed or has bad value",l,word);
 235         continue;
 236       }
 237       ads->searchndots= v;
 238       continue;
 239     }
 240     if (l>=12 && !memcmp(word,"adns_checkc:",12)) {
 241       if (!strcmp(word+12,"none")) {
 242         ads->iflags &= ~adns_if_checkc_freq;
 243         ads->iflags |= adns_if_checkc_entex;
 244       } else if (!strcmp(word+12,"entex")) {
 245         ads->iflags &= ~adns_if_checkc_freq;
 246         ads->iflags |= adns_if_checkc_entex;
 247       } else if (!strcmp(word+12,"freq")) {
 248         ads->iflags |= adns_if_checkc_freq;
 249       } else {
 250         configparseerr(ads,fn,lno, "option adns_checkc has bad value `%s' "
 251                        "(must be none, entex or freq", word+12);
 252       }
 253       continue;
 254     }
 255     adns__diag(ads,-1,0,"%s:%d: unknown option `%.*s'", fn,lno, l,word);
 256   }
 257 }
 258
 259 static void ccf_clearnss(adns_state ads, const char *fn, int lno, const char *buf) {
 260   ads->nservers= 0;
 261 }
 262
 263 static void ccf_include(adns_state ads, const char *fn, int lno, const char *buf) {
 264   if (!*buf) {
 265     configparseerr(ads,fn,lno,"`include' directive with no filename");
 266     return;
 267   }
 268   readconfig(ads,buf,1);
 269 }
 270
 271 static void ccf_lookup(adns_state ads, const char *fn, int lno,
 272                        const char *buf) {
 273   int found_bind=0;
 274   const char *word;
 275   int l;
 276
 277   if (!*buf) {
 278     configparseerr(ads,fn,lno,"`lookup' directive with no databases");
 279     return;
 280   }
 281
 282   while (nextword(&buf,&word,&l)) {
 283     if (l==4 && !memcmp(word,"bind",4)) {
 284       found_bind=1;
 285     } else if (l==4 && !memcmp(word,"file",4)) {
 286       /* ignore this and hope /etc/hosts is not essential */
 287     } else if (l==2 && !memcmp(word,"yp",2)) {
 288       adns__diag(ads,-1,0,"%s:%d: yp lookups not supported by adns", fn,lno);
 289       found_bind=-1;
 290     } else {
 291       adns__diag(ads,-1,0,"%s:%d: unknown `lookup' database `%.*s'",
 292                  fn,lno, l,word);
 293       found_bind=-1;
 294     }
 295   }
 296   if (!found_bind)
 297     adns__diag(ads,-1,0,"%s:%d: `lookup' specified, but not `bind'", fn,lno);
 298 }
 299
 300 static const struct configcommandinfo {
 301   const char *name;
 302   void (*fn)(adns_state ads, const char *fn, int lno, const char *buf);
 303 } configcommandinfos[]= {
 304   { "nameserver",        ccf_nameserver  },
 305   { "domain",            ccf_search      },
 306   { "search",            ccf_search      },
 307   { "sortlist",          ccf_sortlist    },
 308   { "options",           ccf_options     },
 309   { "clearnameservers",  ccf_clearnss    },
 310   { "include",           ccf_include     },
 311   { "lookup",            ccf_lookup      }, /* OpenBSD */
 312   {  0                                   }
 313 };
 314
 315 typedef union {
 316   FILE *file;
 317   const char *text;
 318 } getline_ctx;
 319
 320 static int gl_file(adns_state ads, getline_ctx *src_io, const char *filename,
 321                    int lno, char *buf, int buflen) {
 322   FILE *file= src_io->file;
 323   int c, i;
 324   char *p;
 325
 326   p= buf;
 327   buflen--;
 328   i= 0;
 329
 330   for (;;) { /* loop over chars */
 331     if (i == buflen) {
 332       adns__diag(ads,-1,0,"%s:%d: line too long, ignored",filename,lno);
 333       goto x_badline;
 334     }
 335     c= getc(file);
 336     if (!c) {
 337       adns__diag(ads,-1,0,"%s:%d: line contains nul, ignored",filename,lno);
 338       goto x_badline;
 339     } else if (c == '\n') {
 340       break;
 341     } else if (c == EOF) {
 342       if (ferror(file)) {
 343         saveerr(ads,errno);
 344         adns__diag(ads,-1,0,"%s:%d: read error: %s",filename,lno,strerror(errno));
 345         return -1;
 346       }
 347       if (!i) return -1;
 348       break;
 349     } else {
 350       *p++= c;
 351       i++;
 352     }
 353   }
 354
 355   *p++= 0;
 356   return i;
 357
 358  x_badline:
 359   saveerr(ads,EINVAL);
 360   while ((c= getc(file)) != EOF && c != '\n');
 361   return -2;
 362 }
 363
 364 static int gl_text(adns_state ads, getline_ctx *src_io, const char *filename,
 365                    int lno, char *buf, int buflen) {
 366   const char *cp= src_io->text;
 367   int l;
 368
 369   if (!cp || !*cp) return -1;
 370
 371   if (*cp == ';' || *cp == '\n') cp++;
 372   l= strcspn(cp,";\n");
 373   src_io->text = cp+l;
 374
 375   if (l >= buflen) {
 376     adns__diag(ads,-1,0,"%s:%d: line too long, ignored",filename,lno);
 377     saveerr(ads,EINVAL);
 378     return -2;
 379   }
 380
 381   memcpy(buf,cp,l);
 382   buf[l]= 0;
 383   return l;
 384 }
 385
 386 static void readconfiggeneric(adns_state ads, const char *filename,
 387                               int (*getline)(adns_state ads, getline_ctx*,
 388                                              const char *filename, int lno,
 389                                              char *buf, int buflen),
 390                               /* Returns >=0 for success, -1 for EOF or error
 391                                * (error will have been reported), or -2 for
 392                                * bad line was encountered, try again.
 393                                */
 394                               getline_ctx gl_ctx) {
 395   char linebuf[2000], *p, *q;
 396   int lno, l, dirl;
 397   const struct configcommandinfo *ccip;
 398
 399   for (lno=1;
 400        (l= getline(ads,&gl_ctx, filename,lno, linebuf,sizeof(linebuf))) != -1;
 401        lno++) {
 402     if (l == -2) continue;
 403     while (l>0 && ctype_whitespace(linebuf[l-1])) l--;
 404     linebuf[l]= 0;
 405     p= linebuf;
 406     while (ctype_whitespace(*p)) p++;
 407     if (*p == '#' || !*p) continue;
 408     q= p;
 409     while (*q && !ctype_whitespace(*q)) q++;
 410     dirl= q-p;
 411     for (ccip=configcommandinfos;
 412          ccip->name && !(strlen(ccip->name)==dirl && !memcmp(ccip->name,p,q-p));
 413          ccip++);
 414     if (!ccip->name) {
 415       adns__diag(ads,-1,0,"%s:%d: unknown configuration directive `%.*s'",
 416                  filename,lno,q-p,p);
 417       continue;
 418     }
 419     while (ctype_whitespace(*q)) q++;
 420     ccip->fn(ads,filename,lno,q);
 421   }
 422 }
 423
 424 static const char *instrum_getenv(adns_state ads, const char *envvar) {
 425   const char *value;
 426
 427   value= getenv(envvar);
 428   if (!value) adns__debug(ads,-1,0,"environment variable %s not set",envvar);
 429   else adns__debug(ads,-1,0,"environment variable %s set to `%s'",envvar,value);
 430   return value;
 431 }
 432
 433 static void readconfig(adns_state ads, const char *filename, int warnmissing) {
 434   getline_ctx gl_ctx;
 435
 436   gl_ctx.file= fopen(filename,"r");
 437   if (!gl_ctx.file) {
 438     if (errno == ENOENT) {
 439       if (warnmissing)
 440         adns__debug(ads,-1,0,"configuration file `%s' does not exist",filename);
 441       return;
 442     }
 443     saveerr(ads,errno);
 444     adns__diag(ads,-1,0,"cannot open configuration file `%s': %s",
 445                filename,strerror(errno));
 446     return;
 447   }
 448
 449   readconfiggeneric(ads,filename,gl_file,gl_ctx);
 450
 451   fclose(gl_ctx.file);
 452 }
 453
 454 static void readconfigtext(adns_state ads, const char *text, const char *showname) {
 455   getline_ctx gl_ctx;
 456
 457   gl_ctx.text= text;
 458   readconfiggeneric(ads,showname,gl_text,gl_ctx);
 459 }
 460
 461 static void readconfigenv(adns_state ads, const char *envvar) {
 462   const char *filename;
 463
 464   if (ads->iflags & adns_if_noenv) {
 465     adns__debug(ads,-1,0,"not checking environment variable `%s'",envvar);
 466     return;
 467   }
 468   filename= instrum_getenv(ads,envvar);
 469   if (filename) readconfig(ads,filename,1);
 470 }
 471
 472 static void readconfigenvtext(adns_state ads, const char *envvar) {
 473   const char *textdata;
 474
 475   if (ads->iflags & adns_if_noenv) {
 476     adns__debug(ads,-1,0,"not checking environment variable `%s'",envvar);
 477     return;
 478   }
 479   textdata= instrum_getenv(ads,envvar);
 480   if (textdata) readconfigtext(ads,textdata,envvar);
 481 }
 482
 483
 484 int adns__setnonblock(adns_state ads, int fd) {
 485   int r;
 486
 487   r= fcntl(fd,F_GETFL,0); if (r<0) return errno;
 488   r |= O_NONBLOCK;
 489   r= fcntl(fd,F_SETFL,r); if (r<0) return errno;
 490   return 0;
 491 }
 492
 493 static int init_begin(adns_state *ads_r, adns_initflags flags, FILE *diagfile) {
 494   adns_state ads;
 495
 496   ads= malloc(sizeof(*ads)); if (!ads) return errno;
 497
 498   ads->iflags= flags;
 499   ads->diagfile= diagfile;
 500   ads->configerrno= 0;
 501   LIST_INIT(ads->udpw);
 502   LIST_INIT(ads->tcpw);
 503   LIST_INIT(ads->childw);
 504   LIST_INIT(ads->output);
 505   ads->forallnext= 0;
 506   ads->nextid= 0x311f;
 507   ads->udpsocket= ads->tcpsocket= -1;
 508   adns__vbuf_init(&ads->tcpsend);
 509   adns__vbuf_init(&ads->tcprecv);
 510   ads->tcprecv_skip= 0;
 511   ads->nservers= ads->nsortlist= ads->nsearchlist= ads->tcpserver= 0;
 512   ads->searchndots= 1;
 513   ads->tcpstate= server_disconnected;
 514   timerclear(&ads->tcptimeout);
 515   ads->searchlist= 0;
 516
 517   *ads_r= ads;
 518   return 0;
 519 }
 520
 521 static int init_finish(adns_state ads) {
 522   struct in_addr ia;
 523   struct protoent *proto;
 524   int r;
 525
 526   if (!ads->nservers) {
 527     if (ads->diagfile && ads->iflags & adns_if_debug)
 528       fprintf(ads->diagfile,"adns: no nameservers, using localhost\n");
 529     ia.s_addr= htonl(INADDR_LOOPBACK);
 530     addserver(ads,ia);
 531   }
 532
 533   proto= getprotobyname("udp"); if (!proto) { r= ENOPROTOOPT; goto x_free; }
 534   ads->udpsocket= socket(AF_INET,SOCK_DGRAM,proto->p_proto);
 535   if (ads->udpsocket<0) { r= errno; goto x_free; }
 536
 537   r= adns__setnonblock(ads,ads->udpsocket);
 538   if (r) { r= errno; goto x_closeudp; }
 539
 540   return 0;
 541
 542  x_closeudp:
 543   close(ads->udpsocket);
 544  x_free:
 545   free(ads);
 546   return r;
 547 }
 548
 549 static void init_abort(adns_state ads) {
 550   if (ads->nsearchlist) {
 551     free(ads->searchlist[0]);
 552     free(ads->searchlist);
 553   }
 554   free(ads);
 555 }
 556
 557 int adns_init(adns_state *ads_r, adns_initflags flags, FILE *diagfile) {
 558   adns_state ads;
 559   const char *res_options, *adns_res_options;
 560   int r;
 561
 562   r= init_begin(&ads, flags, diagfile ? diagfile : stderr);
 563   if (r) return r;
 564
 565   res_options= instrum_getenv(ads,"RES_OPTIONS");
 566   adns_res_options= instrum_getenv(ads,"ADNS_RES_OPTIONS");
 567   ccf_options(ads,"RES_OPTIONS",-1,res_options);
 568   ccf_options(ads,"ADNS_RES_OPTIONS",-1,adns_res_options);
 569
 570   readconfig(ads,"/etc/resolv.conf",1);
 571   readconfig(ads,"/etc/resolv-adns.conf",0);
 572   readconfigenv(ads,"RES_CONF");
 573   readconfigenv(ads,"ADNS_RES_CONF");
 574
 575   readconfigenvtext(ads,"RES_CONF_TEXT");
 576   readconfigenvtext(ads,"ADNS_RES_CONF_TEXT");
 577
 578   ccf_options(ads,"RES_OPTIONS",-1,res_options);
 579   ccf_options(ads,"ADNS_RES_OPTIONS",-1,adns_res_options);
 580
 581   ccf_search(ads,"LOCALDOMAIN",-1,instrum_getenv(ads,"LOCALDOMAIN"));
 582   ccf_search(ads,"ADNS_LOCALDOMAIN",-1,instrum_getenv(ads,"ADNS_LOCALDOMAIN"));
 583
 584   if (ads->configerrno && ads->configerrno != EINVAL) {
 585     r= ads->configerrno;
 586     init_abort(ads);
 587     return r;
 588   }
 589
 590   r= init_finish(ads);
 591   if (r) return r;
 592
 593   adns__consistency(ads,0,cc_entex);
 594   *ads_r= ads;
 595   return 0;
 596 }
 597
 598 int adns_init_strcfg(adns_state *ads_r, adns_initflags flags,
 599                      FILE *diagfile, const char *configtext) {
 600   adns_state ads;
 601   int r;
 602
 603   r= init_begin(&ads, flags, diagfile);  if (r) return r;
 604
 605   readconfigtext(ads,configtext,"<supplied configuration text>");
 606   if (ads->configerrno) {
 607     r= ads->configerrno;
 608     init_abort(ads);
 609     return r;
 610   }
 611
 612   r= init_finish(ads);  if (r) return r;
 613   adns__consistency(ads,0,cc_entex);
 614   *ads_r= ads;
 615   return 0;
 616 }
 617
 618
 619 void adns_finish(adns_state ads) {
 620   adns__consistency(ads,0,cc_entex);
 621   for (;;) {
 622     if (ads->udpw.head) adns_cancel(ads->udpw.head);
 623     else if (ads->tcpw.head) adns_cancel(ads->tcpw.head);
 624     else if (ads->childw.head) adns_cancel(ads->childw.head);
 625     else if (ads->output.head) adns_cancel(ads->output.head);
 626     else break;
 627   }
 628   close(ads->udpsocket);
 629   if (ads->tcpsocket >= 0) close(ads->tcpsocket);
 630   adns__vbuf_free(&ads->tcpsend);
 631   adns__vbuf_free(&ads->tcprecv);
 632   freesearchlist(ads);
 633   free(ads);
 634 }
 635
 636 void adns_forallqueries_begin(adns_state ads) {
 637   adns__consistency(ads,0,cc_entex);
 638   ads->forallnext=
 639     ads->udpw.head ? ads->udpw.head :
 640     ads->tcpw.head ? ads->tcpw.head :
 641     ads->childw.head ? ads->childw.head :
 642     ads->output.head;
 643 }
 644
 645 adns_query adns_forallqueries_next(adns_state ads, void **context_r) {
 646   adns_query qu, nqu;
 647
 648   adns__consistency(ads,0,cc_entex);
 649   nqu= ads->forallnext;
 650   for (;;) {
 651     qu= nqu;
 652     if (!qu) return 0;
 653     if (qu->next) {
 654       nqu= qu->next;
 655     } else if (qu == ads->udpw.tail) {
 656       nqu=
 657         ads->tcpw.head ? ads->tcpw.head :
 658         ads->childw.head ? ads->childw.head :
 659         ads->output.head;
 660     } else if (qu == ads->tcpw.tail) {
 661       nqu=
 662         ads->childw.head ? ads->childw.head :
 663         ads->output.head;
 664     } else if (qu == ads->childw.tail) {
 665       nqu= ads->output.head;
 666     } else {
 667       nqu= 0;
 668     }
 669     if (!qu->parent) break;
 670   }
 671   ads->forallnext= nqu;
 672   if (context_r) *context_r= qu->ctx.ext;
 673   return qu;
 674 }