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) 1999-2000 Ian Jackson <ian@davenant.greenend.org.uk>
   8  *
   9  *  It is part of adns, which is
  10  *    Copyright (C) 1997-2000 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/types.h>
  37 #include <unistd.h>
  38 #include <fcntl.h>
  39
  40 #include "config.h"
  41 #include "adns.h"
  42 #include "dlist.h"
  43 #include "tvarith.h"
  44
  45 #ifdef ADNS_REGRESS_TEST
  46 # include "hredirect.h"
  47 #endif
  48
  49 struct outqueuenode {
  50   struct outqueuenode *next, *back;
  51   void *buffer;
  52   char *textp;
  53   int textlen;
  54   struct timeval printbefore;
  55   struct treething *addr;
  56 };
  57
  58 static int bracket, forever, address;
  59 static unsigned long timeout= 1000;
  60 static adns_rrtype rrt= adns_r_ptr;
  61 static adns_initflags initflags= 0;
  62 static const char *config_text;
  63
  64 static int outblocked, inputeof;
  65 static struct { struct outqueuenode *head, *tail; } outqueue;
  66 static int peroutqueuenode, outqueuelen;
  67
  68 static struct sockaddr_in sa;
  69 static adns_state ads;
  70
  71 static char addrtextbuf[14];
  72 static int cbyte, inbyte, inbuf;
  73 static unsigned char bytes[4];
  74 static struct timeval printbefore;
  75
  76 struct treething {
  77   unsigned char bytes[4];
  78   adns_query qu;
  79   adns_answer *ans;
  80 };
  81
  82 static struct treething *newthing;
  83 static void *treeroot;
  84
  85 static int nonblock(int fd, int isnonblock) {
  86   int r;
  87
  88   r= fcntl(fd,F_GETFL);
  89   if (r==-1) return -1;
  90   r= fcntl(fd,F_SETFL, isnonblock ? r|O_NONBLOCK : r&~O_NONBLOCK);
  91   if (r==-1) return -1;
  92   return 0;
  93 }
  94
  95 static void quit(int exitstatus) NONRETURNING;
  96 static void quit(int exitstatus) {
  97   nonblock(0,0);
  98   nonblock(1,0);
  99   exit(exitstatus);
 100 }
 101
 102 static void sysfail(const char *what) NONRETURNING;
 103 static void sysfail(const char *what) {
 104   fprintf(stderr,"adnsresfilter: system call failed: %s: %s\n",what,strerror(errno));
 105   quit(2);
 106 }
 107
 108 static void *xmalloc(size_t sz) {
 109   void *r;
 110   r= malloc(sz);  if (r) return r;
 111   sysfail("malloc");
 112 }
 113
 114 static void outputerr(void) NONRETURNING;
 115 static void outputerr(void) { sysfail("write to stdout"); }
 116
 117 static void usage(void) {
 118   if (printf("usage: adnsresfilter [<options ...>]\n"
 119              "       adnsresfilter  -h|--help\n"
 120              "options: -t<milliseconds>|--timeout <milliseconds>\n"
 121              "         -w|--wait        (always wait for queries to time out or fail)\n"
 122              "         -b|--brackets    (require [...] around IP addresses)\n"
 123              "         -a|--address     (always include [address] in output)\n"
 124              "         -u|--unchecked   (do not forward map for checking)\n"
 125              "         --config <text>  (use this instead of resolv.conf)\n"
 126              "         --debug          (turn on adns resolver debugging)\n"
 127              "Timeout is the maximum amount to delay any particular bit of output for.\n"
 128              "Lookups will go on in the background.  Default timeout = 1000 (ms).\n")
 129       == EOF) outputerr();
 130 }
 131
 132 static void usageerr(const char *why) NONRETURNING;
 133 static void usageerr(const char *why) {
 134   fprintf(stderr,"adnsresfilter: bad usage: %s\n",why);
 135   usage();
 136   quit(1);
 137 }
 138
 139 static void adnsfail(const char *what, int e) NONRETURNING;
 140 static void adnsfail(const char *what, int e) {
 141   fprintf(stderr,"adnsresfilter: adns call failed: %s: %s\n",what,strerror(e));
 142   quit(2);
 143 }
 144
 145 static void settimeout(const char *arg) {
 146   char *ep;
 147   timeout= strtoul(arg,&ep,0);
 148   if (*ep) usageerr("invalid timeout");
 149 }
 150
 151 static void parseargs(const char *const *argv) {
 152   const char *arg;
 153   int c;
 154
 155   while ((arg= *++argv)) {
 156     if (arg[0] != '-') usageerr("no non-option arguments are allowed");
 157     if (arg[1] == '-') {
 158       if (!strcmp(arg,"--timeout")) {
 159         if (!(arg= *++argv)) usageerr("--timeout needs a value");
 160         settimeout(arg);
 161         forever= 0;
 162       } else if (!strcmp(arg,"--wait")) {
 163         forever= 1;
 164       } else if (!strcmp(arg,"--brackets")) {
 165         bracket= 1;
 166       } else if (!strcmp(arg,"--address")) {
 167         address= 1;
 168       } else if (!strcmp(arg,"--unchecked")) {
 169         rrt= adns_r_ptr_raw;
 170       } else if (!strcmp(arg,"--config")) {
 171         if (!(arg= *++argv)) usageerr("--config needs a value");
 172         config_text= arg;
 173       } else if (!strcmp(arg,"--debug")) {
 174         initflags |= adns_if_debug;
 175       } else if (!strcmp(arg,"--help")) {
 176         usage(); quit(0);
 177       } else {
 178         usageerr("unknown long option");
 179       }
 180     } else {
 181       while ((c= *++arg)) {
 182         switch (c) {
 183         case 't':
 184           if (*++arg) settimeout(arg);
 185           else if ((arg= *++argv)) settimeout(arg);
 186           else usageerr("-t needs a value");
 187           forever= 0;
 188           arg= "\0";
 189           break;
 190         case 'w':
 191           forever= 1;
 192           break;
 193         case 'b':
 194           bracket= 1;
 195           break;
 196         case 'a':
 197           address= 1;
 198           break;
 199         case 'u':
 200           rrt= adns_r_ptr_raw;
 201           break;
 202         case 'h':
 203           usage();
 204           quit(0);
 205         default:
 206           usageerr("unknown short option");
 207         }
 208       }
 209     }
 210   }
 211 }
 212
 213 static void queueoutchar(int c) {
 214   struct outqueuenode *entry;
 215
 216   entry= outqueue.tail;
 217   if (!entry || entry->addr || entry->textlen >= peroutqueuenode) {
 218     peroutqueuenode= !peroutqueuenode || !entry || entry->addr ? 128 :
 219       peroutqueuenode >= 1024 ? 4096 : peroutqueuenode<<2;
 220     entry= xmalloc(sizeof(*entry));
 221     entry->buffer= xmalloc(peroutqueuenode);
 222     entry->textp= entry->buffer;
 223     entry->textlen= 0;
 224     entry->addr= 0;
 225     LIST_LINK_TAIL(outqueue,entry);
 226     outqueuelen++;
 227   }
 228   entry->textp[entry->textlen++]= c;
 229 }
 230
 231 static void queueoutstr(const char *str, int len) {
 232   while (len-- > 0) queueoutchar(*str++);
 233 }
 234
 235 static void writestdout(struct outqueuenode *entry) {
 236   int r;
 237
 238   while (entry->textlen) {
 239     r= write(1, entry->textp, entry->textlen);
 240     if (r < 0) {
 241       if (errno == EINTR) continue;
 242       if (errno == EAGAIN) { outblocked= 1; break; }
 243       sysfail("write stdout");
 244     }
 245     assert(r <= entry->textlen);
 246     entry->textp += r;
 247     entry->textlen -= r;
 248   }
 249   if (!entry->textlen) {
 250     LIST_UNLINK(outqueue,entry);
 251     free(entry->buffer);
 252     free(entry);
 253     outqueuelen--;
 254   }
 255 }
 256
 257 static void replacetextwithname(struct outqueuenode *entry) {
 258   char *name, *newbuf;
 259   int namelen, newlen;
 260
 261   name= entry->addr->ans->rrs.str[0];
 262   namelen= strlen(name);
 263   if (!address) {
 264     free(entry->buffer);
 265     entry->buffer= 0;
 266     entry->textp= name;
 267     entry->textlen= namelen;
 268   } else {
 269     newlen= entry->textlen + namelen + (bracket ? 0 : 2);
 270     newbuf= xmalloc(newlen + 1);
 271     sprintf(newbuf, bracket ? "%s%.*s" : "%s[%.*s]", name, entry->textlen, entry->textp);
 272     free(entry->buffer);
 273     entry->buffer= entry->textp= newbuf;
 274     entry->textlen= newlen;
 275   }
 276 }
 277
 278 static void checkadnsqueries(void) {
 279   adns_query qu;
 280   adns_answer *ans;
 281   void *context;
 282   struct treething *foundthing;
 283   int r;
 284
 285   for (;;) {
 286     qu= 0; context= 0; ans= 0;
 287     r= adns_check(ads,&qu,&ans,&context);
 288     if (r == ESRCH || r == EAGAIN) break;
 289     assert(!r);
 290     foundthing= context;
 291     foundthing->ans= ans;
 292     foundthing->qu= 0;
 293   }
 294 }
 295
 296 static void restartbuf(void) {
 297   if (inbuf>0) queueoutstr(addrtextbuf,inbuf);
 298   inbuf= 0;
 299 }
 300
 301 static int comparer(const void *a, const void *b) {
 302   return memcmp(a,b,4);
 303 }
 304
 305 static void procaddr(void) {
 306   struct treething *foundthing;
 307   void **searchfound;
 308   struct outqueuenode *entry;
 309   int r;
 310
 311   if (!newthing) {
 312     newthing= xmalloc(sizeof(struct treething));
 313     newthing->qu= 0;
 314     newthing->ans= 0;
 315   }
 316
 317   memcpy(newthing->bytes,bytes,4);
 318   searchfound= tsearch(newthing,&treeroot,comparer);
 319   if (!searchfound) sysfail("tsearch");
 320   foundthing= *searchfound;
 321
 322   if (foundthing == newthing) {
 323     newthing= 0;
 324     memcpy(&sa.sin_addr,bytes,4);
 325     r= adns_submit_reverse(ads, (const struct sockaddr*)&sa,
 326                            rrt,0,foundthing,&foundthing->qu);
 327     if (r) adnsfail("submit",r);
 328   }
 329   entry= xmalloc(sizeof(*entry));
 330   entry->buffer= xmalloc(inbuf);
 331   entry->textp= entry->buffer;
 332   memcpy(entry->textp,addrtextbuf,inbuf);
 333   entry->textlen= inbuf;
 334   entry->addr= foundthing;
 335   entry->printbefore= printbefore;
 336   LIST_LINK_TAIL(outqueue,entry);
 337   outqueuelen++;
 338   inbuf= 0;
 339   cbyte= -1;
 340 }
 341
 342 static void startaddr(void) {
 343   bytes[cbyte=0]= 0;
 344   inbyte= 0;
 345 }
 346
 347 static void readstdin(void) {
 348   char readbuf[512], *p;
 349   int r, c, nbyte;
 350
 351   while ((r= read(0,readbuf,sizeof(readbuf))) <= 0) {
 352     if (r == 0) { inputeof= 1; return; }
 353     if (r == EAGAIN) return;
 354     if (r != EINTR) sysfail("read stdin");
 355   }
 356   for (p=readbuf; r>0; r--,p++) {
 357     c= *p;
 358     if (cbyte==-1 && bracket && c=='[') {
 359       addrtextbuf[inbuf++]= c;
 360       startaddr();
 361     } else if (cbyte==-1 && !bracket && !isalnum(c)) {
 362       queueoutchar(c);
 363       startaddr();
 364     } else if (cbyte>=0 && inbyte<3 && c>='0' && c<='9' &&
 365                (nbyte= bytes[cbyte]*10 + (c-'0')) <= 255) {
 366       bytes[cbyte]= nbyte;
 367       addrtextbuf[inbuf++]= c;
 368       inbyte++;
 369     } else if (cbyte>=0 && cbyte<3 && inbyte>0 && c=='.') {
 370       bytes[++cbyte]= 0;
 371       addrtextbuf[inbuf++]= c;
 372       inbyte= 0;
 373     } else if (cbyte==3 && inbyte>0 && bracket && c==']') {
 374       addrtextbuf[inbuf++]= c;
 375       procaddr();
 376     } else if (cbyte==3 && inbyte>0 && !bracket && !isalnum(c)) {
 377       procaddr();
 378       queueoutchar(c);
 379       startaddr();
 380     } else {
 381       restartbuf();
 382       queueoutchar(c);
 383       cbyte= -1;
 384       if (!bracket && !isalnum(c)) startaddr();
 385     }
 386   }
 387 }
 388
 389 static void startup(void) {
 390   int r;
 391
 392   if (nonblock(0,1)) sysfail("set stdin to nonblocking mode");
 393   if (nonblock(1,1)) sysfail("set stdout to nonblocking mode");
 394   memset(&sa,0,sizeof(sa));
 395   sa.sin_family= AF_INET;
 396   if (config_text) {
 397     r= adns_init_strcfg(&ads,initflags,stderr,config_text);
 398   } else {
 399     r= adns_init(&ads,initflags,0);
 400   }
 401   if (r) adnsfail("init",r);
 402   cbyte= -1;
 403   inbyte= -1;
 404   inbuf= 0;
 405   if (!bracket) startaddr();
 406 }
 407
 408 int main(int argc, const char *const *argv) {
 409   int r, maxfd;
 410   fd_set readfds, writefds, exceptfds;
 411   struct outqueuenode *entry;
 412   struct timeval *tv, tvbuf, now;
 413
 414   parseargs(argv);
 415   startup();
 416
 417   while (!inputeof || outqueue.head) {
 418     maxfd= 2;
 419     tv= 0;
 420     FD_ZERO(&readfds); FD_ZERO(&writefds); FD_ZERO(&exceptfds);
 421     if ((entry= outqueue.head) && !outblocked) {
 422       if (!entry->addr) {
 423         writestdout(entry);
 424         continue;
 425       }
 426       if (entry->addr->ans) {
 427         if (entry->addr->ans->nrrs)
 428           replacetextwithname(entry);
 429         entry->addr= 0;
 430         continue;
 431       }
 432       r= gettimeofday(&now,0);  if (r) sysfail("gettimeofday");
 433       if (forever) {
 434         tv= 0;
 435       } else if (!timercmp(&now,&entry->printbefore,<)) {
 436         entry->addr= 0;
 437         continue;
 438       } else {
 439         tvbuf.tv_sec= entry->printbefore.tv_sec - now.tv_sec - 1;
 440         tvbuf.tv_usec= entry->printbefore.tv_usec - now.tv_usec + 1000000;
 441         tvbuf.tv_sec += tvbuf.tv_usec / 1000000;
 442         tvbuf.tv_usec %= 1000000;
 443         tv= &tvbuf;
 444       }
 445       adns_beforeselect(ads,&maxfd,&readfds,&writefds,&exceptfds,
 446                         &tv,&tvbuf,&now);
 447     }
 448     if (outblocked) FD_SET(1,&writefds);
 449     if (!inputeof && outqueuelen<1024) FD_SET(0,&readfds);
 450
 451     r= select(maxfd,&readfds,&writefds,&exceptfds,tv);
 452     if (r < 0) { if (r == EINTR) continue; else sysfail("select"); }
 453
 454     r= gettimeofday(&now,0);  if (r) sysfail("gettimeofday");
 455     adns_afterselect(ads,maxfd,&readfds,&writefds,&exceptfds,&now);
 456     checkadnsqueries();
 457
 458     if (FD_ISSET(0,&readfds)) {
 459       if (!forever) {
 460         printbefore= now;
 461         timevaladd(&printbefore,timeout);
 462       }
 463       readstdin();
 464     } else if (FD_ISSET(1,&writefds)) {
 465       outblocked= 0;
 466     }
 467   }
 468   if (nonblock(0,0)) sysfail("un-nonblock stdin");
 469   if (nonblock(1,0)) sysfail("un-nonblock stdout");
 470   if (ferror(stdin) || fclose(stdin)) sysfail("read stdin");
 471   if (fclose(stdout)) sysfail("close stdout");
 472   exit(0);
 473 }