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, timeout=10;
  53 static adns_rrtype rrt= adns_r_ptr;
  54
  55 static int outblocked, inputeof;
  56 static struct { struct outqueuenode *head, *tail; } outqueue;
  57 static int peroutqueuenode, outqueuelen;
  58
  59 static struct sockaddr_in sa;
  60 static adns_state ads;
  61
  62 static char addrtextbuf[14];
  63 static int cbyte, inbyte, inbuf;
  64 static unsigned char bytes[4];
  65 static struct timeval printbefore;
  66
  67 struct treething {
  68   unsigned char bytes[4];
  69   adns_query qu;
  70   adns_answer *ans;
  71 };
  72
  73 static struct treething *newthing;
  74 static void *treeroot;
  75
  76 static int nonblock(int fd, int isnonblock) {
  77   int r;
  78
  79   r= fcntl(fd,F_GETFL);
  80   if (r==-1) return -1;
  81   r= fcntl(fd,F_SETFL, isnonblock ? r|O_NONBLOCK : r&~O_NONBLOCK);
  82   if (r==-1) return -1;
  83   return 0;
  84 }
  85
  86 static void quit(int exitstatus) NONRETURNING;
  87 static void quit(int exitstatus) {
  88   nonblock(0,0);
  89   nonblock(1,0);
  90   exit(exitstatus);
  91 }
  92
  93 static void sysfail(const char *what) NONRETURNING;
  94 static void sysfail(const char *what) {
  95   fprintf(stderr,"adnsresfilter: system call failed: %s: %s\n",what,strerror(errno));
  96   quit(2);
  97 }
  98
  99 static void *xmalloc(size_t sz) {
 100   void *r;
 101   r= malloc(sz);  if (r) return r;
 102   sysfail("malloc");
 103 }
 104
 105 static void outputerr(void) NONRETURNING;
 106 static void outputerr(void) { sysfail("write to stdout"); }
 107
 108 static void usage(void) {
 109   if (printf("usage: adnsresfilter [<options ...>]\n"
 110              "       adnsresfilter  -h|--help\n"
 111              "options: -b|--brackets\n"
 112              "         -w|--wait\n"
 113              "         -t<timeout>|--timeout <timeout>\n"
 114              "         -u|--unchecked\n")
 115       == EOF) outputerr();
 116 }
 117
 118 static void usageerr(const char *why) NONRETURNING;
 119 static void usageerr(const char *why) {
 120   fprintf(stderr,"adnsresfilter: bad usage: %s\n",why);
 121   usage();
 122   quit(1);
 123 }
 124
 125 static void adnsfail(const char *what, int e) NONRETURNING;
 126 static void adnsfail(const char *what, int e) {
 127   fprintf(stderr,"adnsresfilter: adns call failed: %s: %s\n",what,strerror(e));
 128   quit(2);
 129 }
 130
 131 static int comparer(const void *a, const void *b) {
 132   return memcmp(a,b,4);
 133 }
 134
 135 static void parseargs(const char *const *argv) {
 136   const char *arg;
 137   int c;
 138
 139   while ((arg= *++argv)) {
 140     if (arg[0] != '-') usageerr("no non-option arguments are allowed");
 141     if (arg[1] == '-') {
 142       if (!strcmp(arg,"--brackets")) {
 143         bracket= 1;
 144       } else if (!strcmp(arg,"--unchecked")) {
 145         rrt= adns_r_ptr_raw;
 146       } else if (!strcmp(arg,"--wait")) {
 147         forever= 1;
 148       } else if (!strcmp(arg,"--help")) {
 149         usage(); quit(0);
 150       } else {
 151         usageerr("unknown long option");
 152       }
 153     } else {
 154       while ((c= *++arg)) {
 155         switch (c) {
 156         case 'b':
 157           bracket= 1;
 158           break;
 159         case 'u':
 160           rrt= adns_r_ptr_raw;
 161           break;
 162         case 'w':
 163           forever= 1;
 164           break;
 165         case 'h':
 166           usage(); quit(0);
 167         default:
 168           usageerr("unknown short option");
 169         }
 170       }
 171     }
 172   }
 173 }
 174
 175 static void queueoutchar(int c) {
 176   struct outqueuenode *entry;
 177
 178   entry= outqueue.tail;
 179   if (!entry->back || entry->addr || entry->textlen >= peroutqueuenode) {
 180     entry= xmalloc(sizeof(*entry));
 181     peroutqueuenode= !entry->back || entry->addr ? 32 :
 182       peroutqueuenode >= 1024 ? 2048 : peroutqueuenode<<1;
 183     entry->buffer= xmalloc(peroutqueuenode);
 184     entry->textp= entry->buffer;
 185     entry->textlen= 0;
 186     entry->addr= 0;
 187     LIST_LINK_TAIL(outqueue,entry);
 188     outqueuelen++;
 189   }
 190   *entry->textp++= c;
 191   entry->textlen++;
 192 }
 193
 194 static void queueoutstr(const char *str, int len) {
 195   while (len > 0) queueoutchar(*str++);
 196 }
 197
 198 static void writestdout(struct outqueuenode *entry) {
 199   int r;
 200
 201   while (entry->textlen) {
 202     r= write(1, entry->textp, entry->textlen);
 203     if (r < 0) {
 204       if (errno == EINTR) continue;
 205       if (errno == EAGAIN) { outblocked= 1; break; }
 206       sysfail("write stdout");
 207     }
 208     assert(r < entry->textlen);
 209     entry->textp += r;
 210     entry->textlen -= r;
 211   }
 212   if (!entry->textlen) {
 213     LIST_UNLINK(outqueue,entry);
 214     free(entry->buffer);
 215     free(entry);
 216     outqueuelen--;
 217   }
 218 }
 219
 220 static void replacetextwithname(struct outqueuenode *entry) {
 221   free(entry->buffer);
 222   entry->buffer= 0;
 223   entry->textp= entry->addr->ans->rrs.str[0];
 224   entry->textlen= strlen(entry->textp);
 225 }
 226
 227 static void checkadnsqueries(void) {
 228   adns_query qu;
 229   adns_answer *ans;
 230   void *context;
 231   struct treething *foundthing;
 232   int r;
 233
 234   for (;;) {
 235     qu= 0; context= 0; ans= 0;
 236     r= adns_check(ads,&qu,&ans,&context);
 237     if (r == ESRCH || r == EAGAIN) break;
 238     assert(!r);
 239     foundthing= context;
 240     foundthing->ans= ans;
 241     foundthing->qu= 0;
 242   }
 243 }
 244
 245 static void restartbuf(void) {
 246   if (inbuf>0) queueoutstr(addrtextbuf,inbuf);
 247   inbuf= 0;
 248 }
 249
 250 static void procaddr(void) {
 251   struct treething *foundthing;
 252   void **searchfound;
 253   struct outqueuenode *entry;
 254   int r;
 255
 256   if (!newthing) {
 257     newthing= xmalloc(sizeof(struct treething));
 258     newthing->qu= 0;
 259     newthing->ans= 0;
 260   }
 261
 262   memcpy(newthing->bytes,bytes,4);
 263   searchfound= tsearch(newthing,&treeroot,comparer);
 264   if (!searchfound) sysfail("tsearch");
 265   foundthing= *searchfound;
 266
 267   if (foundthing == newthing) {
 268     memcpy(&sa.sin_addr,bytes,4);
 269     r= adns_submit_reverse(ads, (const struct sockaddr*)&sa,
 270                            rrt,0,foundthing,&foundthing->qu);
 271     if (r) adnsfail("submit",r);
 272   }
 273   entry= xmalloc(sizeof(*entry));
 274   entry->buffer= xmalloc(inbuf);
 275   entry->textp= entry->buffer;
 276   memcpy(entry->textp,addrtextbuf,inbuf);
 277   entry->textlen= inbuf;
 278   entry->addr= foundthing;
 279   LIST_LINK_TAIL(outqueue,entry);
 280   outqueuelen++;
 281   inbuf= 0;
 282   cbyte= -1;
 283 }
 284
 285 static void startaddr(void) {
 286   bytes[cbyte=0]= 0;
 287   inbyte= 0;
 288 }
 289
 290 static void readstdin(void) {
 291   char readbuf[512], *p;
 292   int r, c, nbyte;
 293
 294   while ((r= read(0,readbuf,sizeof(readbuf))) <= 0) {
 295     if (r == 0) { inputeof= 1; return; }
 296     if (r == EAGAIN) return;
 297     if (r != EINTR) sysfail("read stdin");
 298   }
 299   for (p=readbuf; r>0; r--,p++) {
 300     c= *p++;
 301     if (cbyte==-1 && bracket && c=='[') {
 302       addrtextbuf[inbuf++]= c;
 303       startaddr();
 304     } else if (cbyte==-1 && !bracket && !isalnum(c)) {
 305       queueoutchar(c);
 306       startaddr();
 307     } else if (cbyte>=0 && inbyte<3 && c>='0' && c<='9' &&
 308                (nbyte= bytes[cbyte]*10 + (c-'0')) <= 255) {
 309       bytes[cbyte]= nbyte;
 310       addrtextbuf[inbuf++]= c;
 311       inbyte++;
 312     } else if (cbyte>=0 && cbyte<3 && inbyte>0 && c=='.') {
 313       bytes[++cbyte]= 0;
 314       addrtextbuf[inbuf++]= c;
 315       inbyte= 0;
 316     } else if (cbyte==3 && inbyte>0 && bracket && c==']') {
 317       addrtextbuf[inbuf++]= c;
 318       procaddr();
 319     } else if (cbyte==3 && inbyte>0 && !bracket && !isalnum(c)) {
 320       procaddr();
 321       queueoutchar(c);
 322       startaddr();
 323     } else {
 324       restartbuf();
 325       queueoutchar(c);
 326       cbyte= -1;
 327       if (!bracket && !isalnum(c)) startaddr();
 328     }
 329   }
 330   if (cbyte==3 && inbyte>0 && !bracket) procaddr();
 331 }
 332
 333 static void startup(void) {
 334   int r;
 335
 336   if (setvbuf(stdout,0,_IOLBF,0)) sysfail("setvbuf stdout");
 337   if (nonblock(0,1)) sysfail("set stdin to nonblocking mode");
 338   if (nonblock(1,1)) sysfail("set stdout to nonblocking mode");
 339   memset(&sa,0,sizeof(sa));
 340   sa.sin_family= AF_INET;
 341   r= adns_init(&ads,0,0);  if (r) adnsfail("init",r);
 342   cbyte= -1;
 343   inbyte= -1;
 344   inbuf= 0;
 345   if (!bracket) startaddr();
 346 }
 347
 348 int main(int argc, const char *const *argv) {
 349   int r, maxfd;
 350   fd_set readfds, writefds, exceptfds;
 351   struct outqueuenode *entry;
 352   struct timeval *tv, tvbuf, now;
 353
 354   parseargs(argv);
 355   startup();
 356
 357   while (!inputeof || outqueue.head) {
 358     maxfd= 2;
 359     tv= 0;
 360     FD_ZERO(&readfds); FD_ZERO(&writefds); FD_ZERO(&exceptfds);
 361     if ((entry= outqueue.head) && !outblocked) {
 362       if (!entry->addr) {
 363         writestdout(entry);
 364         continue;
 365       } else if (entry->addr->ans) {
 366         if (entry->addr->ans->nrrs)
 367           replacetextwithname(entry);
 368         entry->addr= 0;
 369         continue;
 370       }
 371       r= gettimeofday(&now,0);  if (r) sysfail("gettimeofday");
 372       if (forever) {
 373         tv= 0;
 374       } else if (!timercmp(&now,&entry->printbefore,<)) {
 375         entry->addr= 0;
 376         continue;
 377       } else {
 378         tvbuf.tv_sec= printbefore.tv_sec - now.tv_sec - 1;
 379         tvbuf.tv_usec= printbefore.tv_usec - now.tv_usec + 1000000;
 380         tvbuf.tv_sec += tvbuf.tv_usec / 1000000;
 381         tvbuf.tv_usec %= 1000000;
 382         tv= &tvbuf;
 383       }
 384       adns_beforeselect(ads,&maxfd,&readfds,&writefds,&exceptfds,
 385                         &tv,&tvbuf,&now);
 386     }
 387     if (outblocked) FD_SET(1,&writefds);
 388     if (!inputeof && outqueuelen<1000) FD_SET(0,&readfds);
 389
 390     r= select(maxfd,&readfds,&writefds,&exceptfds,tv);
 391     if (r < 0) { if (r == EINTR) continue; else sysfail("select"); }
 392
 393     r= gettimeofday(&now,0);  if (r) sysfail("gettimeofday");
 394     adns_afterselect(ads,maxfd,&readfds,&writefds,&exceptfds,&now);
 395     checkadnsqueries();
 396
 397     if (FD_ISSET(0,&readfds)) {
 398       if (!forever) {
 399         printbefore= now;
 400         timevaladd(&printbefore,timeout);
 401       }
 402       readstdin();
 403     } else if (FD_ISSET(1,&writefds)) {
 404       outblocked= 0;
 405     }
 406   }
 407   if (ferror(stdin) || fclose(stdin)) sysfail("read stdin");
 408   if (fclose(stdout)) sysfail("close stdout");
 409   if (nonblock(0,0)) sysfail("un-nonblock stdin");
 410   if (nonblock(1,0)) sysfail("un-nonblock stdout");
 411   exit(0);
 412 }