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

   1 /*
   2  * adnsresfilter.c
   3  * - filter which does resolving, not part of the library
   4  */
   5 /*
   6  *  This file is
   7  *    Copyright (C) 1999 Ian Jackson <ian@davenant.greenend.org.uk>
   8  *
   9  *  It is part of adns, which is
  10  *    Copyright (C) 1997-1999 Ian Jackson <ian@davenant.greenend.org.uk>
  11  *    Copyright (C) 1999 Tony Finch <dot@dotat.at>
  12  *
  13  *  This program is free software; you can redistribute it and/or modify
  14  *  it under the terms of the GNU General Public License as published by
  15  *  the Free Software Foundation; either version 2, or (at your option)
  16  *  any later version.
  17  *
  18  *  This program is distributed in the hope that it will be useful,
  19  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  20  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21  *  GNU General Public License for more details.
  22  *
  23  *  You should have received a copy of the GNU General Public License
  24  *  along with this program; if not, write to the Free Software Foundation,
  25  *  Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  26  */
  27
  28 #include <stdio.h>
  29 #include <stdlib.h>
  30 #include <string.h>
  31 #include <errno.h>
  32 #include <search.h>
  33 #include <assert.h>
  34 #include <ctype.h>
  35
  36 #include <sys/fcntl.h>
  37
  38 #include "adns.h"
  39 #include "config.h"
  40 #include "dlist.h"
  41 #include "tvarith.h"
  42
  43 struct outqueuenode {
  44   struct outqueuenode *next, *back;
  45   void *buffer;
  46   char *textp;
  47   int textlen;
  48   struct timeval printbefore;
  49   struct treething *addr;
  50 };
  51
  52 static int bracket, forever;
  53 static unsigned long timeout=100;
  54 static adns_rrtype rrt= adns_r_ptr;
  55
  56 static int outblocked, inputeof;
  57 static struct { struct outqueuenode *head, *tail; } outqueue;
  58 static int peroutqueuenode, outqueuelen;
  59
  60 static struct sockaddr_in sa;
  61 static adns_state ads;
  62
  63 static char addrtextbuf[14];
  64 static int cbyte, inbyte, inbuf;
  65 static unsigned char bytes[4];
  66 static struct timeval printbefore;
  67
  68 struct treething {
  69   unsigned char bytes[4];
  70   adns_query qu;
  71   adns_answer *ans;
  72 };
  73
  74 static struct treething *newthing;
  75 static void *treeroot;
  76
  77 static int nonblock(int fd, int isnonblock) {
  78   int r;
  79
  80   r= fcntl(fd,F_GETFL);
  81   if (r==-1) return -1;
  82   r= fcntl(fd,F_SETFL, isnonblock ? r|O_NONBLOCK : r&~O_NONBLOCK);
  83   if (r==-1) return -1;
  84   return 0;
  85 }
  86
  87 static void quit(int exitstatus) NONRETURNING;
  88 static void quit(int exitstatus) {
  89   nonblock(0,0);
  90   nonblock(1,0);
  91   exit(exitstatus);
  92 }
  93
  94 static void sysfail(const char *what) NONRETURNING;
  95 static void sysfail(const char *what) {
  96   fprintf(stderr,"adnsresfilter: system call failed: %s: %s\n",what,strerror(errno));
  97   quit(2);
  98 }
  99
 100 static void *xmalloc(size_t sz) {
 101   void *r;
 102   r= malloc(sz);  if (r) return r;
 103   sysfail("malloc");
 104 }
 105
 106 static void outputerr(void) NONRETURNING;
 107 static void outputerr(void) { sysfail("write to stdout"); }
 108
 109 static void usage(void) {
 110   if (printf("usage: adnsresfilter [<options ...>]\n"
 111              "       adnsresfilter  -h|--help\n"
 112              "options: -b|--brackets\n"
 113              "         -w|--wait\n"
 114              "         -t<timeout>|--timeout <milliseconds>\n"
 115              "         -u|--unchecked\n")
 116       == EOF) outputerr();
 117 }
 118
 119 static void usageerr(const char *why) NONRETURNING;
 120 static void usageerr(const char *why) {
 121   fprintf(stderr,"adnsresfilter: bad usage: %s\n",why);
 122   usage();
 123   quit(1);
 124 }
 125
 126 static void adnsfail(const char *what, int e) NONRETURNING;
 127 static void adnsfail(const char *what, int e) {
 128   fprintf(stderr,"adnsresfilter: adns call failed: %s: %s\n",what,strerror(e));
 129   quit(2);
 130 }
 131
 132 static void settimeout(const char *arg) {
 133   char *ep;
 134   timeout= strtoul(arg,&ep,0);
 135   if (*ep) usageerr("invalid timeout");
 136 }
 137
 138 static void parseargs(const char *const *argv) {
 139   const char *arg;
 140   int c;
 141
 142   while ((arg= *++argv)) {
 143     if (arg[0] != '-') usageerr("no non-option arguments are allowed");
 144     if (arg[1] == '-') {
 145       if (!strcmp(arg,"--brackets")) {
 146         bracket= 1;
 147       } else if (!strcmp(arg,"--unchecked")) {
 148         rrt= adns_r_ptr_raw;
 149       } else if (!strcmp(arg,"--wait")) {
 150         forever= 1;
 151       } else if (!strcmp(arg,"--help")) {
 152         usage(); quit(0);
 153       } else if (!strcmp(arg,"--timeout")) {
 154         if (!(arg= *++argv)) usageerr("--timeout needs a value");
 155         settimeout(arg);
 156         forever= 0;
 157       } else {
 158         usageerr("unknown long option");
 159       }
 160     } else {
 161       while ((c= *++arg)) {
 162         switch (c) {
 163         case 'b':
 164           bracket= 1;
 165           break;
 166         case 'u':
 167           rrt= adns_r_ptr_raw;
 168           break;
 169         case 'w':
 170           forever= 1;
 171           break;
 172         case 'h':
 173           usage();
 174           quit(0);
 175         case 't':
 176           if (*++arg) settimeout(arg);
 177           else if ((arg= *++argv)) settimeout(arg);
 178           else usageerr("-t needs a value");
 179           forever= 0;
 180           arg= "\0";
 181           break;
 182         default:
 183           usageerr("unknown short option");
 184         }
 185       }
 186     }
 187   }
 188 }
 189
 190 static void queueoutchar(int c) {
 191   struct outqueuenode *entry;
 192
 193   entry= outqueue.tail;
 194   if (!entry || entry->addr || entry->textlen >= peroutqueuenode) {
 195     peroutqueuenode= !peroutqueuenode || !entry || entry->addr ? 128 :
 196       peroutqueuenode >= 1024 ? 4096 : peroutqueuenode<<2;
 197     entry= xmalloc(sizeof(*entry));
 198     entry->buffer= xmalloc(peroutqueuenode);
 199     entry->textp= entry->buffer;
 200     entry->textlen= 0;
 201     entry->addr= 0;
 202     LIST_LINK_TAIL(outqueue,entry);
 203     outqueuelen++;
 204   }
 205   entry->textp[entry->textlen++]= c;
 206 }
 207
 208 static void queueoutstr(const char *str, int len) {
 209   while (len-- > 0) queueoutchar(*str++);
 210 }
 211
 212 static void writestdout(struct outqueuenode *entry) {
 213   int r;
 214
 215   while (entry->textlen) {
 216     r= write(1, entry->textp, entry->textlen);
 217     if (r < 0) {
 218       if (errno == EINTR) continue;
 219       if (errno == EAGAIN) { outblocked= 1; break; }
 220       sysfail("write stdout");
 221     }
 222     assert(r <= entry->textlen);
 223     entry->textp += r;
 224     entry->textlen -= r;
 225   }
 226   if (!entry->textlen) {
 227     LIST_UNLINK(outqueue,entry);
 228     free(entry->buffer);
 229     free(entry);
 230     outqueuelen--;
 231   }
 232 }
 233
 234 static void replacetextwithname(struct outqueuenode *entry) {
 235   free(entry->buffer);
 236   entry->buffer= 0;
 237   entry->textp= entry->addr->ans->rrs.str[0];
 238   entry->textlen= strlen(entry->textp);
 239 }
 240
 241 static void checkadnsqueries(void) {
 242   adns_query qu;
 243   adns_answer *ans;
 244   void *context;
 245   struct treething *foundthing;
 246   int r;
 247
 248   for (;;) {
 249     qu= 0; context= 0; ans= 0;
 250     r= adns_check(ads,&qu,&ans,&context);
 251     if (r == ESRCH || r == EAGAIN) break;
 252     assert(!r);
 253     foundthing= context;
 254     foundthing->ans= ans;
 255     foundthing->qu= 0;
 256   }
 257 }
 258
 259 static void restartbuf(void) {
 260   if (inbuf>0) queueoutstr(addrtextbuf,inbuf);
 261   inbuf= 0;
 262 }
 263
 264 static int comparer(const void *a, const void *b) {
 265   return memcmp(a,b,4);
 266 }
 267
 268 static void procaddr(void) {
 269   struct treething *foundthing;
 270   void **searchfound;
 271   struct outqueuenode *entry;
 272   int r;
 273
 274   if (!newthing) {
 275     newthing= xmalloc(sizeof(struct treething));
 276     newthing->qu= 0;
 277     newthing->ans= 0;
 278   }
 279
 280   memcpy(newthing->bytes,bytes,4);
 281   searchfound= tsearch(newthing,&treeroot,comparer);
 282   if (!searchfound) sysfail("tsearch");
 283   foundthing= *searchfound;
 284
 285   if (foundthing == newthing) {
 286     newthing= 0;
 287     memcpy(&sa.sin_addr,bytes,4);
 288     r= adns_submit_reverse(ads, (const struct sockaddr*)&sa,
 289                            rrt,0,foundthing,&foundthing->qu);
 290     if (r) adnsfail("submit",r);
 291   }
 292   entry= xmalloc(sizeof(*entry));
 293   entry->buffer= xmalloc(inbuf);
 294   entry->textp= entry->buffer;
 295   memcpy(entry->textp,addrtextbuf,inbuf);
 296   entry->textlen= inbuf;
 297   entry->addr= foundthing;
 298   entry->printbefore= printbefore;
 299   LIST_LINK_TAIL(outqueue,entry);
 300   outqueuelen++;
 301   inbuf= 0;
 302   cbyte= -1;
 303 }
 304
 305 static void startaddr(void) {
 306   bytes[cbyte=0]= 0;
 307   inbyte= 0;
 308 }
 309
 310 static void readstdin(void) {
 311   char readbuf[512], *p;
 312   int r, c, nbyte;
 313
 314   while ((r= read(0,readbuf,sizeof(readbuf))) <= 0) {
 315     if (r == 0) { inputeof= 1; return; }
 316     if (r == EAGAIN) return;
 317     if (r != EINTR) sysfail("read stdin");
 318   }
 319   for (p=readbuf; r>0; r--,p++) {
 320     c= *p;
 321     if (cbyte==-1 && bracket && c=='[') {
 322       addrtextbuf[inbuf++]= c;
 323       startaddr();
 324     } else if (cbyte==-1 && !bracket && !isalnum(c)) {
 325       queueoutchar(c);
 326       startaddr();
 327     } else if (cbyte>=0 && inbyte<3 && c>='0' && c<='9' &&
 328                (nbyte= bytes[cbyte]*10 + (c-'0')) <= 255) {
 329       bytes[cbyte]= nbyte;
 330       addrtextbuf[inbuf++]= c;
 331       inbyte++;
 332     } else if (cbyte>=0 && cbyte<3 && inbyte>0 && c=='.') {
 333       bytes[++cbyte]= 0;
 334       addrtextbuf[inbuf++]= c;
 335       inbyte= 0;
 336     } else if (cbyte==3 && inbyte>0 && bracket && c==']') {
 337       addrtextbuf[inbuf++]= c;
 338       procaddr();
 339     } else if (cbyte==3 && inbyte>0 && !bracket && !isalnum(c)) {
 340       procaddr();
 341       queueoutchar(c);
 342       startaddr();
 343     } else {
 344       restartbuf();
 345       queueoutchar(c);
 346       cbyte= -1;
 347       if (!bracket && !isalnum(c)) startaddr();
 348     }
 349   }
 350   if (cbyte==3 && inbyte>0 && !bracket) procaddr();
 351 }
 352
 353 static void startup(void) {
 354   int r;
 355
 356   if (nonblock(0,1)) sysfail("set stdin to nonblocking mode");
 357   if (nonblock(1,1)) sysfail("set stdout to nonblocking mode");
 358   memset(&sa,0,sizeof(sa));
 359   sa.sin_family= AF_INET;
 360   r= adns_init(&ads,0,0);  if (r) adnsfail("init",r);
 361   cbyte= -1;
 362   inbyte= -1;
 363   inbuf= 0;
 364   if (!bracket) startaddr();
 365 }
 366
 367 int main(int argc, const char *const *argv) {
 368   int r, maxfd;
 369   fd_set readfds, writefds, exceptfds;
 370   struct outqueuenode *entry;
 371   struct timeval *tv, tvbuf, now;
 372
 373   parseargs(argv);
 374   startup();
 375
 376   while (!inputeof || outqueue.head) {
 377     maxfd= 2;
 378     tv= 0;
 379     FD_ZERO(&readfds); FD_ZERO(&writefds); FD_ZERO(&exceptfds);
 380     if ((entry= outqueue.head) && !outblocked) {
 381       if (!entry->addr) {
 382         writestdout(entry);
 383         continue;
 384       }
 385       if (entry->addr->ans) {
 386         if (entry->addr->ans->nrrs)
 387           replacetextwithname(entry);
 388         entry->addr= 0;
 389         continue;
 390       }
 391       r= gettimeofday(&now,0);  if (r) sysfail("gettimeofday");
 392       if (forever) {
 393         tv= 0;
 394       } else if (!timercmp(&now,&entry->printbefore,<)) {
 395         entry->addr= 0;
 396         continue;
 397       } else {
 398         tvbuf.tv_sec= entry->printbefore.tv_sec - now.tv_sec - 1;
 399         tvbuf.tv_usec= entry->printbefore.tv_usec - now.tv_usec + 1000000;
 400         tvbuf.tv_sec += tvbuf.tv_usec / 1000000;
 401         tvbuf.tv_usec %= 1000000;
 402         tv= &tvbuf;
 403       }
 404       adns_beforeselect(ads,&maxfd,&readfds,&writefds,&exceptfds,
 405                         &tv,&tvbuf,&now);
 406     }
 407     if (outblocked) FD_SET(1,&writefds);
 408     if (!inputeof && outqueuelen<1024) FD_SET(0,&readfds);
 409
 410     r= select(maxfd,&readfds,&writefds,&exceptfds,tv);
 411     if (r < 0) { if (r == EINTR) continue; else sysfail("select"); }
 412
 413     r= gettimeofday(&now,0);  if (r) sysfail("gettimeofday");
 414     adns_afterselect(ads,maxfd,&readfds,&writefds,&exceptfds,&now);
 415     checkadnsqueries();
 416
 417     if (FD_ISSET(0,&readfds)) {
 418       if (!forever) {
 419         printbefore= now;
 420         timevaladd(&printbefore,timeout);
 421       }
 422       readstdin();
 423     } else if (FD_ISSET(1,&writefds)) {
 424       outblocked= 0;
 425     }
 426   }
 427   if (nonblock(0,0)) sysfail("un-nonblock stdin");
 428   if (nonblock(1,0)) sysfail("un-nonblock stdout");
 429   if (ferror(stdin) || fclose(stdin)) sysfail("read stdin");
 430   if (fclose(stdout)) sysfail("close stdout");
 431   exit(0);
 432 }