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

   1 /**/
   2
   3 #include <stdarg.h>
   4 #include <stdio.h>
   5 #include <errno.h>
   6 #include <string.h>
   7 #include <stdlib.h>
   8 #include <assert.h>
   9 #include <unistd.h>
  10
  11 #include <netdb.h>
  12 #include <arpa/nameser.h>
  13 #include <sys/socket.h>
  14 #include <netinet/in.h>
  15 #include <arpa/inet.h>
  16
  17 #include "adns-internal.h"
  18
  19 #define LIST_UNLINK_PART(list,node,part) \
  20   do { \
  21     if ((node)->back) (node)->back->part next= (node)->part next; \
  22       else                        (list).head= (node)->part next; \
  23     if ((node)->next) (node)->next->part back= (node)->part back; \
  24       else                        (list).tail= (node)->part back; \
  25   } while(0)
  26
  27 #define LIST_LINK_TAIL_PART(list,node,part) \
  28   do { \
  29     (node)->part back= 0; \
  30     (node)->part next= (list).tail; \
  31     if ((list).tail) (list).tail->part back= (node); else (list).part head= (node); \
  32     (list).tail= (node); \
  33   } while(0)
  34
  35 #define LIST_UNLINK(list,node) LIST_UNLINK_PART(list,node,)
  36 #define LIST_LINK_TAIL_PART(list,node) LIST_LINK_TAIL(list,node,)
  37
  38 static void vdebug(adns_state ads, const char *fmt, va_list al) {
  39   if (!(ads->iflags & adns_if_debug)) return;
  40   fputs("adns debug: ",stderr);
  41   vfprintf(stderr,fmt,al);
  42   fputc('\n',stderr);
  43 }
  44
  45 static void debug(adns_state ads, const char *fmt, ...) {
  46   va_list al;
  47
  48   va_start(al,fmt);
  49   vdebug(ads,fmt,al);
  50   va_end(al);
  51 }
  52
  53 static void vdiag(adns_state ads, const char *fmt, va_list al) {
  54   if (ads->iflags & adns_if_noerrprint) return;
  55   fputs("adns: ",stderr);
  56   vfprintf(stderr,fmt,al);
  57   fputc('\n',stderr);
  58 }
  59
  60 static void diag(adns_state ads, const char *fmt, ...) {
  61   va_list al;
  62
  63   va_start(al,fmt);
  64   vdiag(ads,fmt,al);
  65   va_end(al);
  66 }
  67
  68 static void addserver(adns_state ads, struct in_addr addr) {
  69   int i;
  70   struct server *ss;
  71
  72   for (i=0; i<ads->nservers; i++) {
  73     if (ads->servers[i].addr.s_addr == addr.s_addr) {
  74       debug(ads,"duplicate nameserver %s ignored",inet_ntoa(addr));
  75       return;
  76     }
  77   }
  78
  79   if (ads->nservers>=MAXSERVERS) {
  80     diag(ads,"too many nameservers, ignoring %s",inet_ntoa(addr));
  81     return;
  82   }
  83
  84   ss= ads->servers+ads->nservers;
  85   ss->addr= addr;
  86   ss->state= server_disc;
  87   ss->connw.head= ss->connw.tail= 0;
  88   ads->nservers++;
  89 }
  90
  91 static void configparseerr(adns_state ads, const char *fn, int lno,
  92                            const char *fmt, ...) {
  93   va_list al;
  94
  95   if (ads->iflags & adns_if_noerrprint) return;
  96   if (lno==-1) fprintf(stderr,"adns: %s: ",fn);
  97   else fprintf(stderr,"adns: %s:%d: ",fn,lno);
  98   va_start(al,fmt);
  99   vfprintf(stderr,fmt,al);
 100   va_end(al);
 101   fputc('\n',stderr);
 102 }
 103
 104 static void ccf_nameserver(adns_state ads, const char *fn, int lno, const char *buf) {
 105   struct in_addr ia;
 106
 107   if (!inet_aton(buf,&ia)) {
 108     configparseerr(ads,fn,lno,"invalid nameserver address `%s'",buf);
 109     return;
 110   }
 111   debug(ads,"using nameserver %s",inet_ntoa(ia));
 112   addserver(ads,ia);
 113 }
 114
 115 static void ccf_search(adns_state ads, const char *fn, int lno, const char *buf) {
 116   if (!buf) return;
 117   diag(ads,"warning - `search' ignored FIXME");
 118 }
 119
 120 static void ccf_sortlist(adns_state ads, const char *fn, int lno, const char *buf) {
 121   diag(ads,"warning - `sortlist' ignored FIXME");
 122 }
 123
 124 static void ccf_options(adns_state ads, const char *fn, int lno, const char *buf) {
 125   if (!buf) return;
 126   diag(ads,"warning - `options' ignored FIXME");
 127 }
 128
 129 static void ccf_clearnss(adns_state ads, const char *fn, int lno, const char *buf) {
 130   ads->nservers= 0;
 131 }
 132
 133 static const struct configcommandinfo {
 134   const char *name;
 135   void (*fn)(adns_state ads, const char *fn, int lno, const char *buf);
 136 } configcommandinfos[]= {
 137   { "nameserver",        ccf_nameserver  },
 138   { "domain",            ccf_search      },
 139   { "search",            ccf_search      },
 140   { "sortlist",          ccf_sortlist    },
 141   { "options",           ccf_options     },
 142   { "clearnameservers",  ccf_clearnss    },
 143   {  0                                   }
 144 };
 145
 146 static int ctype_whitespace(int c) { return c==' ' || c=='\n' || c=='\t'; }
 147 static int ctype_digit(int c) { return c>='0' && c<='9'; }
 148
 149 static void readconfig(adns_state ads, const char *filename) {
 150   char linebuf[2000], *p, *q;
 151   FILE *file;
 152   int lno, l, c;
 153   const struct configcommandinfo *ccip;
 154
 155   file= fopen(filename,"r");
 156   if (!file) {
 157     if (errno == ENOENT) {
 158       debug(ads,"configuration file `%s' does not exist",filename);
 159       return;
 160     }
 161     diag(ads,"cannot open configuration file `%s': %s",filename,strerror(errno));
 162     return;
 163   }
 164
 165   for (lno=1; fgets(linebuf,sizeof(linebuf),file); lno++) {
 166     l= strlen(linebuf);
 167     if (!l) continue;
 168     if (linebuf[l-1] != '\n' && !feof(file)) {
 169       diag(ads,"%s:%d: line too long",filename,lno);
 170       while ((c= getc(file)) != EOF && c != '\n') { }
 171       if (c == EOF) break;
 172       continue;
 173     }
 174     while (l>0 && ctype_whitespace(linebuf[l-1])) l--;
 175     linebuf[l]= 0;
 176     p= linebuf;
 177     while (ctype_whitespace(*p)) p++;
 178     if (*p == '#' || *p == '\n') continue;
 179     q= p;
 180     while (*q && !ctype_whitespace(*q)) q++;
 181     for (ccip=configcommandinfos;
 182          ccip->name && strncmp(ccip->name,p,q-p);
 183          ccip++);
 184     if (!ccip->name) {
 185       diag(ads,"%s:%d: unknown configuration directive `%.*s'",filename,lno,q-p,p);
 186       continue;
 187     }
 188     while (ctype_whitespace(*q)) q++;
 189     ccip->fn(ads,filename,lno,q);
 190   }
 191   if (ferror(file)) {
 192     diag(ads,"%s:%d: read error: %s",filename,lno,strerror(errno));
 193   }
 194   fclose(file);
 195 }
 196
 197 static const char *instrum_getenv(adns_state ads, const char *envvar) {
 198   const char *value;
 199
 200   value= getenv(envvar);
 201   if (!value) debug(ads,"environment variable %s not set",envvar);
 202   else debug(ads,"environment variable %s set to `%s'",envvar,value);
 203   return value;
 204 }
 205
 206 static void readconfigenv(adns_state ads, const char *envvar) {
 207   const char *filename;
 208
 209   if (ads->iflags & adns_if_noenv) {
 210     debug(ads,"not checking environment variable `%s'",envvar);
 211     return;
 212   }
 213   filename= instrum_getenv(ads,envvar);
 214   if (filename) readconfig(ads,filename);
 215 }
 216
 217 int adns_init(adns_state *ads_r, adns_initflags flags) {
 218   adns_state ads;
 219   const char *res_options, *adns_res_options;
 220   struct protoent *proto;
 221   int r;
 222
 223   ads= malloc(sizeof(*ads)); if (!ads) return errno;
 224   ads->tosend.head= ads->tosend.tail= 0;
 225   ads->timew.head= ads->timew.tail= 0;
 226   ads->childw.head= ads->childw.tail= 0;
 227   ads->output.head= ads->output.tail= 0;
 228   ads->nextid= 0x311f;
 229   ads->udpsocket= -1;
 230   ads->qbufavail= 0;
 231   ads->qbuf= 0;
 232   ads->tcpbufavail= ads->tcpbufused= ads->tcpbufdone= 0;
 233   ads->tcpbuf= 0;
 234   ads->iflags= flags;
 235   ads->nservers= 0;
 236   ads->iflags= flags;
 237
 238   res_options= instrum_getenv(ads,"RES_OPTIONS");
 239   adns_res_options= instrum_getenv(ads,"ADNS_RES_OPTIONS");
 240   ccf_options(ads,"RES_OPTIONS",-1,res_options);
 241   ccf_options(ads,"ADNS_RES_OPTIONS",-1,adns_res_options);
 242
 243   readconfig(ads,"/etc/resolv.conf");
 244   readconfigenv(ads,"RES_CONF");
 245   readconfigenv(ads,"ADNS_RES_CONF");
 246
 247   ccf_options(ads,"RES_OPTIONS",-1,res_options);
 248   ccf_options(ads,"ADNS_RES_OPTIONS",-1,adns_res_options);
 249
 250   ccf_search(ads,"LOCALDOMAIN",-1,instrum_getenv(ads,"LOCALDOMAIN"));
 251   ccf_search(ads,"ADNS_LOCALDOMAIN",-1,instrum_getenv(ads,"ADNS_LOCALDOMAIN"));
 252
 253   if (!ads->nservers) {
 254     struct in_addr ia;
 255     if (ads->iflags & adns_if_debug)
 256       fprintf(stderr,"adns: no nameservers, using localhost\n");
 257     ia.s_addr= INADDR_LOOPBACK;
 258     addserver(ads,ia);
 259   }
 260
 261   proto= getprotobyname("udp"); if (!proto) { r= ENOPROTOOPT; goto x_free; }
 262   ads->udpsocket= socket(AF_INET,SOCK_DGRAM,proto->p_proto);
 263   if (!ads->udpsocket) { r= errno; goto x_closeudp; }
 264
 265   *ads_r= ads;
 266   return 0;
 267
 268  x_closeudp:
 269   close(ads->udpsocket);
 270  x_free:
 271   free(ads);
 272   return r;
 273 }
 274
 275 static void query_fail(adns_state ads, adns_query qu, adns_status stat) {
 276   adns_answer *ans;
 277
 278   ans= qu->answer;
 279   if (!ans) ans= malloc(sizeof(*qu->answer));
 280   if (ans) {
 281     ans->status= stat;
 282     ans->cname= 0;
 283     ans->type= qu->type;
 284     ans->nrrs= 0;
 285   }
 286   qu->answer= ans;
 287   qu->id= -1;
 288   LIST_LINK_TAIL(ads->output,qu);
 289 }
 290
 291 int adns_finish(adns_state ads) {
 292   abort(); /* FIXME */
 293 }
 294
 295 static void autosys(adns_state ads, struct timeval now) {
 296   if (ads->iflags & adns_if_noautosys) return;
 297   adns_callback(ads,-1,0,0,0);
 298 }
 299
 300 void adns_cancel(adns_state ads, adns_query query) {
 301   abort(); /* FIXME */
 302 }
 303
 304 static int callb_checkfd(int maxfd, const fd_set *fds, int fd) {
 305   return maxfd<0 || !fds ? 1 :
 306          fd<maxfd && FD_ISSET(fd,fds);
 307 }
 308
 309 int adns_callback(adns_state ads, int maxfd,
 310                   const fd_set *readfds, const fd_set *writefds,
 311                   const fd_set *exceptfds) {
 312   int skip, dgramlen, count;
 313   enum adns__tcpstate oldtcpstate;
 314
 315   count= 0;
 316   oldtcpstate= ads->tcpstate;
 317
 318   if (ads->tcpstate == server_connecting) {
 319     if (callb_checkfd(maxfd,writefds,ads->tcpsocket)) {
 320       count++;
 321       assert(ads->tcprecv.used==0);
 322       vbuf_ensure(&ads->tcprecv,1);
 323       if (ads->tcprecv.buf) {
 324         r= read(ads->tcpsocket,&ads->tcprecv.buf,1);
 325         if (r==0 || (r<0 && (errno==EAGAIN || errno==EWOULDBLOCK))) {
 326           diag("nameserver %s TCP connection made",
 327                inet_ntoa(ads->servers[ads->tcpserver].addr));
 328           ads->tcpstate= server_connected;
 329         } else if (r>0) {
 330           tcpserver_broken(ads,"connect/read","sent data before first request");
 331         } else if (errno!=EINTR) {
 332           tcpserver_broken(ads,"connect",strerror(errno));
 333         }
 334       }
 335     }
 336   }
 337   if (ads->tcpstate == server_connected) {
 338     if (oldtcpstate == server_connected)
 339       count+= callb_checkfd(maxfd,readfds,ads->tcpsocket) +
 340               callb_checkfd(maxfd,exceptfds,ads->tcpsocket) +
 341         (ads->tcpsend.used && callb_checkfd(maxfd,writefds,ads->tcpsocket));
 342     if (oldtcpstate != server_connected || callb_checkfd(maxfd,readfds,ads->tcpsocket)) {
 343       skip= 0;
 344       for (;;) {
 345         if (ads->tcprecv.used<skip+2) {
 346           want= 2;
 347         } else {
 348           dgramlen= (ads->tcprecv.buf[skip]<<8) | ads->tcprecv.buf[skip+1];
 349           if (ads->tcprecv.used<skip+2+dgramlen) {
 350             want= 2+dgramlen;
 351           } else {
 352             procdgram(ads,ads->tcprecv.buf+skip+2,dgramlen,-1);
 353             skip+= 2+dgramlen; continue;
 354           }
 355         }
 356         Ads->tcprecv.used -= skip;
 357         memmove(ads->tcprecv.buf,ads->tcprecv.buf+skip,ads->tcprecv.used);
 358         vbuf_ensure(&ads->tcprecv,want);
 359         if (ads->tcprecv.used >= ads->tcprecv.avail) break;
 360         r= read(ads->tcpsocket,
 361                 ads->tcprecv.buf+ads->tcprecv.used,
 362                 ads->tcprecv.avail-ads->tcprecv.used);
 363         if (r>0) {
 364           ads->tcprecv.used+= r;
 365         } else {
 366           if (r<0) {
 367             if (errno==EAGAIN || errno==EWOULDBLOCK || errno==ENOMEM) break;
 368             if (errno==EINTR) continue;
 369           }
 370           tcpserver_broken(ads->tcpserver,"read",r?strerror(errno):"closed");
 371           break;
 372         }
 373       }
 374     } else if (callb_checkfd(maxfd,exceptfds,ads->tcpsocket)) {
 375       tcpserver_broken(ads->tcpserver,"select","exceptional condition detected");
 376     } else if (ads->tcpsend.used && callb_checkfd(maxfd,writefds,ads->tcpsocket)) {
 377       r= write(ads->tcpsocket,ads->tcpsend.buf,ads->tcpsend.used);
 378       if (r<0) {
 379         if (errno!=EAGAIN && errno!=EWOULDBLOCK && errno!=ENOMEM && errno!=EINTR) {
 380           tcpserver_broken(ads->tcpserver,"write",strerror(errno));
 381         }
 382       } else if (r>0) {
 383         ads->tcpsend.used -= r;
 384         memmove(ads->tcpsend.buf,ads->tcpsend.buf+r,ads->tcpsend.used);
 385       }
 386     }
 387   }
 388
 389   if (
 390     break;
 391
 392
 393         }
 394
 395   tcpserver_broken(
 396
 397             if (ads-
 398           used= 0;
 399           for (;;) {
 400           vbuf_ensure(&ads->tcprecv,2);
 401           vbuf_ensure(&ads->tcprecv,
 402           if (ads->tcprecv.avail<2) break;
 403       if (ads->tcprecv.used
 404
 405       if (ads->tcprecv.used<2 && ads->tcprecv.avail
 406       if (ads->tcprecv.used<2 && ads->tcprecv.avail
 407       r= read(ads->tcpsocket,
 408       if (adns->tcprecv.used<2) {
 409         if (
 410
 411   if (ads->tcpstate != server_disc) {
 412
 413
 414     }
 415   if (maxfd<0 || !readfds || (FD_ISSET
 416       ads->
 417
 418   abort(); /* FIXME */
 419 }
 420           diag("nameserver #%d (%s) TCP connection died: %s",
 421                inet_ntoa(ads->servers[tcpserver].addr),
 422
 423 static void inter_maxto(struct timeval **tv_io, struct timeval *tvbuf,
 424                         struct timeval maxto) {
 425   struct timeval rbuf;
 426
 427   rbuf= *tv_io;
 428   if (!rbuf) { *tvbuf= maxto; *tv_io= tvbuf; return; }
 429   if (timercmp(rbuf,&maxto,>)) *rbuf= maxto;
 430 }
 431
 432 static void inter_maxtoabs(struct timeval **tv_io, struct timeval *tvbuf,
 433                            struct timeval now, struct timeval maxtime) {
 434   ldiv_t dr;
 435
 436   maxtime.tv_sec -= (now.tv_sec-1);
 437   maxtime.tv_usec += (1000-now.tv_usec);
 438   dr= ldiv(maxtime.tv_usec,1000);
 439   maxtime.tv_sec += dr.quot;
 440   maxtime.tv_usec -= dr.rem;
 441   inter_maxto(tv_io,tvbuf,maxtime);
 442 }
 443
 444 static void localresourcerr(struct timeval **tv_io, struct timeval *tvbuf,
 445                             const char *syscall) {
 446   struct timeval tvto_lr;
 447
 448   diag(ads,"local system resources scarce (during %s): %s",syscall,strerror(errno));
 449   timerclear(&tvto_lr); timevaladd(&tvto_lr,LOCALRESOURCEMS);
 450   inter_maxto(tv_io, tvbuf, tvto_lr);
 451   return;
 452 }
 453
 454 static inline void timevaladd(struct timeval *tv_io, long ms) {
 455   struct timeval tmp;
 456   assert(ms>=0);
 457   tmp= *tv_io;
 458   tmp.tv_usec += (ms%1000)*1000;
 459   tmp.tv_sec += ms/1000;
 460   if (tmp.tv_usec >= 1000) { tmp.tv_sec++; tmp.tv_usec -= 1000; }
 461   *tv_io= tmp;
 462 }
 463
 464 static void inter_addfd(int *maxfd, fd_set *fds, int fd) {
 465   if (fd>=*maxfd) *maxfd= fd+1;
 466   FD_SET(fd,fds);
 467 }
 468
 469 void adns_interest(adns_state ads, int *maxfd,
 470                    fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
 471                    struct timeval **tv_io, struct timeval *tvbuf) {
 472   struct timeval now;
 473   adns_query qu;
 474   int r;
 475
 476   r= gettimeofday(&now,0);
 477   if (r) { localresourcerr(tv_io,tvbuf,"gettimeofday"); return; }
 478
 479   for (qu= ads->timew; qu; qu= nqu) {
 480     nqu= qu->next;
 481     if (timercmp(&now,qu->timeout,>)) {
 482       DLIST_UNLINK(ads->timew,qu);
 483       if (qu->nextudpserver == -1) {
 484         query_fail(ads,qu,adns_s_notresponding);
 485       } else {
 486         DLIST_LINKTAIL(ads->tosend,qu);
 487       }
 488     } else {
 489       inter_maxtoabs(tv_io,tvbuf,now,qu->timeout);
 490     }
 491   }
 492
 493   for (qu= ads->tosend; qu; qu= nqu) {
 494     nqu= qu->next;
 495     quproc_tosend(ads,qu,now);
 496   }
 497
 498   inter_addfd(maxfd,readfds,ads->udpsocket);
 499   switch (ads->tcpstate) {
 500   case server_disc:
 501     break;
 502   case server_connecting:
 503     inter_addfd(maxfd,writefds,ads->tcpsocket);
 504     break;
 505   case server_connected:
 506     inter_addfd(maxfd,readfds,ads->tcpsocket);
 507     inter_addfd(maxfd,exceptfds,ads->tcpsocket);
 508     if (ads->opbufused) inter_addfd(maxfd,writefds,ads->tcpsocket);
 509   default:
 510     abort();
 511   }
 512
 513 }
 514
 515 static int internal_check(adns_state ads,
 516                           adns_query *query_io,
 517                           adns_answer **answer,
 518                           void **context_r) {
 519   adns_query qu;
 520
 521   qu= *query_io;
 522   if (!qu) {
 523     if (!ads->output.head) return EWOULDBLOCK;
 524     qu= ads->output.head;
 525   } else {
 526     if (qu->id>=0) return EWOULDBLOCK;
 527   }
 528   LIST_UNLINK(ads->output,qu);
 529   *answer= qu->answer;
 530   if (context_r) *context_r= qu->context;
 531   free(qu);
 532   return 0;
 533 }
 534
 535 int adns_wait(adns_state ads,
 536               adns_query *query_io,
 537               adns_answer **answer_r,
 538               void **context_r) {
 539   int r, maxfd, rsel, rcb;
 540   fd_set readfds, writefds, exceptfds;
 541   struct timeval tvbuf, *tvp;
 542
 543   for (;;) {
 544     r= internal_check(ads,query_io,answer_r,context_r);
 545     if (r && r != EWOULDBLOCK) return r;
 546     FD_ZERO(&readfds); FD_ZERO(&writefds); FD_ZERO(&exceptfds);
 547     maxfd= 0; tvp= 0;
 548     adns_interest(ads,&maxfd,&readfds,&writefds,&exceptfds,&tvp,&tvbuf);
 549     rsel= select(maxfd,&readfds,&writefds,&exceptfds,tvp);
 550     if (rsel==-1) return r;
 551     rcb= adns_callback(ads,maxfd,&readfds,&writefds,&exceptfds);
 552     assert(rcb==rsel);
 553   }
 554 }
 555
 556 int adns_check(adns_state ads,
 557                adns_query *query_io,
 558                adns_answer **answer_r,
 559                void **context_r) {
 560   autosys(ads);
 561   return internal_check(ads,query_io,answer_r,context_r);
 562 }
 563
 564 int adns_synchronous(adns_state ads,
 565                      const char *owner,
 566                      adns_rrtype type,
 567                      adns_queryflags flags,
 568                      adns_answer **answer_r) {
 569   adns_query qu;
 570   int r;
 571
 572   r= adns_submit(ads,owner,type,flags,0,&qu);
 573   if (r) return r;
 574
 575   do {
 576     r= adns_wait(ads,&qu,answer_r,0);
 577   } while (r==EINTR);
 578   if (r) adns_cancel(ads,qu);
 579   return r;
 580 }
 581
 582 static adns_status mkquery(adns_state ads, const char *owner, int ol, int id,
 583                            adns_rrtype type, adns_queryflags flags, int *qml_r) {
 584   int ll, c, nlabs, qbufreq;
 585   unsigned char label[255], *nqbuf;
 586   const char *p, *pe;
 587
 588 #define MKQUERY_ADDB(b) *nqbuf++= (b)
 589 #define MKQUERY_ADDW(w) (MKQUERY_ADDB(((w)>>8)&0x0ff), MKQUERY_ADDB((w)&0x0ff))
 590
 591   qbufreq= 12+strlen(owner)+3;
 592   if (ads->qbufavail < qbufreq) {
 593     nqbuf= realloc(ads->qbuf,qbufreq);
 594     if (!nqbuf) return adns_s_nolocalmem;
 595     ads->qbuf= nqbuf; ads->qbufavail= qbufreq;
 596   }
 597   nqbuf= ads->qbuf;
 598
 599   MKQUERY_ADDW(id);
 600   MKQUERY_ADDB(0x01); /* QR=Q(0), OPCODE=QUERY(0000), !AA, !TC, RD */
 601   MKQUERY_ADDB(0x00); /* !RA, Z=000, RCODE=NOERROR(0000) */
 602   MKQUERY_ADDW(1); /* QDCOUNT=1 */
 603   MKQUERY_ADDW(0); /* ANCOUNT=0 */
 604   MKQUERY_ADDW(0); /* NSCOUNT=0 */
 605   MKQUERY_ADDW(0); /* ARCOUNT=0 */
 606   p= owner; pe= owner+ol;
 607   nlabs= 0;
 608   if (!*p) return adns_s_invaliddomain;
 609   do {
 610     ll= 0;
 611     while (p!=pe && (c= *p++)!='.') {
 612       if (c=='\\') {
 613         if (!(flags & adns_f_anyquote)) return adns_s_invaliddomain;
 614         if (ctype_digit(p[0])) {
 615           if (ctype_digit(p[1]) && ctype_digit(p[2])) {
 616             c= (*p++ - '0')*100 + (*p++ - '0')*10 + (*p++ - '0');
 617             if (c >= 256) return adns_s_invaliddomain;
 618           } else {
 619             return adns_s_invaliddomain;
 620           }
 621         } else if (!(c= *p++)) {
 622           return adns_s_invaliddomain;
 623         }
 624       }
 625       if (!(flags & adns_f_anyquote)) {
 626         if ((c >= '0' && c <= '9') || c == '-') {
 627           if (!ll) return adns_s_invaliddomain;
 628         } else if ((c < 'a' || c > 'z') && (c < 'A' && c > 'Z')) {
 629           return adns_s_invaliddomain;
 630         }
 631       }
 632       if (ll == sizeof(label)) return adns_s_invaliddomain;
 633       label[ll++]= c;
 634     }
 635     if (!ll) return adns_s_invaliddomain;
 636     if (nlabs++ > 63) return adns_s_invaliddomain;
 637     MKQUERY_ADDB(ll);
 638     memcpy(nqbuf,label,ll); nqbuf+= ll;
 639   } while (p!=pe);
 640
 641   MKQUERY_ADDB(0);
 642   MKQUERY_ADDW(type & adns__rrt_typemask); /* QTYPE */
 643   MKQUERY_ADDW(1); /* QCLASS=IN */
 644
 645   *qml_r= nqbuf - ads->qbuf;
 646
 647   return adns_s_ok;
 648 }
 649
 650 static adns_query allocquery(adns_state ads, const char *owner, int ol,
 651                              int qml, int id, adns_rrtype type,
 652                              adns_queryflags flags, void *context) {
 653   adns_query qu;
 654   unsigned char *qm;
 655
 656   qu= malloc(sizeof(*qu)+ol+1+qml); if (!qu) return 0;
 657   qu->next= qu->back= qu->parent= 0;
 658   qu->children.head= qu->children.tail= 0;
 659   qu->siblings.next= qu->siblings.back= 0;
 660   qu->id= id;
 661   qu->type= type;
 662   qu->answer= 0;
 663   qu->flags= flags;
 664   qu->context= context;
 665   qu->udpretries= 0;
 666   qu->sentudp= qu->senttcp= 0;
 667   qu->nextserver= 0;
 668   memcpy(qu->owner,owner,ol); qu->owner[ol]= 0;
 669   qu->querymsg= qm= qu->owner+ol+1;
 670   memcpy(qm,ads->qbuf,qml);
 671   qu->querylen= qml;
 672   return qu;
 673 }
 674
 675 static int failsubmit(adns_state ads, void *context, adns_query *query_r,
 676                       adns_rrtype type, adns_queryflags flags,
 677                       int id, adns_status stat) {
 678   adns_query qu;
 679
 680   qu= allocquery(ads,0,0,0,id,type,flags,context); if (!qu) return errno;
 681   query_fail(ads,qu,stat);
 682   *query_r= qu;
 683   return 0;
 684 }
 685
 686 static void quproc_tosend(adns_state ads, adns_query qu, struct timeval now) {
 687   /* Query must be on the `tosend' queue, and guarantees to remove it. */
 688   struct sockaddr_in servaddr;
 689   int serv;
 690
 691   if (qu->nextudpserver != -1) {
 692     if (qu->udpretries >= UDPMAXRETRIES) {
 693       DLIST_UNLINK(ads->tosend,qu);
 694       query_fail(ads,qu,adns_s_notresponding);
 695       return;
 696     }
 697     serv= qu->nextudpserver;
 698     memset(&servaddr,0,sizeof(servaddr));
 699     servaddr.sin_family= AF_INET;
 700     servaddr.sin_addr= ads->servers[serv].addr;
 701     servaddr.sin_port= htons(53);
 702     r= sendto(ads->udpsocket,qu->querymsg,qu->querylen,0,&servaddr,sizeof(servaddr));
 703     if (r<0 && errno == EMSGSIZE) {
 704       qu->nextudpserver= -1;
 705     } else {
 706       if (r<0) {
 707         diag("sendto %s failed: %s",inet_ntoa(servaddr.sin_addr),strerror(errno));
 708       }
 709       DLIST_UNLINK(ads->tosend,qu);
 710       timevaladd(&now,UDPRETRYMS);
 711       qu->timeout= now;
 712       qu->sentudp |= (1<<serv);
 713       qu->nextudpserver= (serv+1)%ads->nservers;
 714       qu->udpretries++;
 715       DLIST_LINKTAIL(ads->timew,qu);
 716       return;
 717     }
 718   }
 719
 720   for (;;) {
 721     serv= tcpserver_get(ads);
 722     if (serv<0) { r=0; break; }
 723     if (ads->opbufused) { r=0; break; }
 724     r= write(ads->tcpsocket,qu->querymsg,qu->querylen);
 725     if (r >= 0) break;
 726     if (errno == EAGAIN || errno == EINTR || errno == ENOSPC ||
 727         errno == ENOBUFS || errno == ENOMEM) {
 728       r= 0; break;
 729     }
 730     tcpserver_broken(serv);
 731   }
 732   if (r < qu->querylen) {
 733     newopbufused= qu->opbufused + (qu->querylen-r);
 734     if (newopbufused > ads->opbufavail) {
 735       newopbufavail= ads->newopbufused<<1;
 736       newopbuf= realloc(newopbufavail);
 737       if (!newopbuf) {
 738         DLIST_UNLINK(ads->tosend,qu);
 739         query_fail(ads,qu,adns_s_nolocalmem);
 740         return;
 741       }
 742       ads->opbuf= newopbuf;
 743       ads->opbufavail= newopbufavail;
 744     }
 745     memcpy(ads->opbuf+ads->opbufused,qu->querymsg+r,qu->querylen-r);
 746     ads->opbufused= newopbufused;
 747   }
 748   DLIST_UNLINK(ads->tosend,qu);
 749   timevaladd(&now,TCPMS);
 750   qu->timeout= now;
 751   qu->senttcp |= (1<<qu->nextserver);
 752   DLIST_LINKTAIL(ads->timew,qu);
 753 }
 754
 755 int adns_submit(adns_state ads,
 756                 const char *owner,
 757                 adns_rrtype type,
 758                 adns_queryflags flags,
 759                 void *context,
 760                 adns_query *query_r) {
 761   adns_query qu;
 762   adns_status stat;
 763   int ol, id, qml;
 764
 765   id= ads->nextid++;
 766
 767   ol= strlen(owner);
 768   if (ol<=1 || ol>MAXDNAME+1)
 769     return failsubmit(ads,context,query_r,type,flags,id,adns_s_invaliddomain);
 770   if (owner[ol-1]=='.' && owner[ol-2]!='\\') { flags &= ~adns_f_search; ol--; }
 771
 772   stat= mkquery(ads,owner,ol,id,type,flags,&qml);
 773   if (stat) return failsubmit(ads,context,query_r,type,flags,id,stat);
 774
 775   qu= allocquery(ads,owner,ol,qml,id,type,flags,context); if (!qu) return errno;
 776   if (qu->flags & adns_f_usevc) qu->udpretries= -1;
 777   LIST_LINK_TAIL(ads->tosend,qu);
 778
 779   r= gettimeofday(&now,0); if (r) return;
 780   quproc_tosend(ads,qu,now);
 781   autosys(ads,now);
 782
 783   *query_r= qu;
 784   return 0;
 785 }