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) 1999-2000 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 #include "client.h"
  45
  46 #ifdef ADNS_REGRESS_TEST
  47 # include "hredirect.h"
  48 #endif
  49
  50 struct outqueuenode {
  51   struct outqueuenode *next, *back;
  52   void *buffer;
  53   char *textp;
  54   int textlen;
  55   struct timeval printbefore;
  56   struct treething *addr;
  57 };
  58
  59 static int bracket, forever, address;
  60 static unsigned long timeout= 1000;
  61 static adns_rrtype rrt= adns_r_ptr;
  62 static adns_initflags initflags= 0;
  63 static const char *config_text;
  64
  65 static int outblocked, inputeof;
  66 static struct { struct outqueuenode *head, *tail; } outqueue;
  67 static int peroutqueuenode, outqueuelen;
  68
  69 static struct sockaddr_in sa;
  70 static adns_state ads;
  71
  72 static char addrtextbuf[14];
  73 static int cbyte, inbyte, inbuf;
  74 static unsigned char bytes[4];
  75 static struct timeval printbefore;
  76
  77 struct treething {
  78   unsigned char bytes[4];
  79   adns_query qu;
  80   adns_answer *ans;
  81 };
  82
  83 static struct treething *newthing;
  84 static void *treeroot;
  85
  86 static int nonblock(int fd, int isnonblock) {
  87   int r;
  88
  89   r= fcntl(fd,F_GETFL);
  90   if (r==-1) return -1;
  91   r= fcntl(fd,F_SETFL, isnonblock ? r|O_NONBLOCK : r&~O_NONBLOCK);
  92   if (r==-1) return -1;
  93   return 0;
  94 }
  95
  96 void quitnow(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   quitnow(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 | --version\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   if (fflush(stdout)) sysfail("flush stdout");
 131 }
 132
 133 static void usageerr(const char *why) NONRETURNING;
 134 static void usageerr(const char *why) {
 135   fprintf(stderr,"adnsresfilter: bad usage: %s\n",why);
 136   usage();
 137   quitnow(1);
 138 }
 139
 140 static void adnsfail(const char *what, int e) NONRETURNING;
 141 static void adnsfail(const char *what, int e) {
 142   fprintf(stderr,"adnsresfilter: adns call failed: %s: %s\n",what,strerror(e));
 143   quitnow(2);
 144 }
 145
 146 static void settimeout(const char *arg) {
 147   char *ep;
 148   timeout= strtoul(arg,&ep,0);
 149   if (*ep) usageerr("invalid timeout");
 150 }
 151
 152 static void parseargs(const char *const *argv) {
 153   const char *arg;
 154   int c;
 155
 156   while ((arg= *++argv)) {
 157     if (arg[0] != '-') usageerr("no non-option arguments are allowed");
 158     if (arg[1] == '-') {
 159       if (!strcmp(arg,"--timeout")) {
 160         if (!(arg= *++argv)) usageerr("--timeout needs a value");
 161         settimeout(arg);
 162         forever= 0;
 163       } else if (!strcmp(arg,"--wait")) {
 164         forever= 1;
 165       } else if (!strcmp(arg,"--brackets")) {
 166         bracket= 1;
 167       } else if (!strcmp(arg,"--address")) {
 168         address= 1;
 169       } else if (!strcmp(arg,"--unchecked")) {
 170         rrt= adns_r_ptr_raw;
 171       } else if (!strcmp(arg,"--config")) {
 172         if (!(arg= *++argv)) usageerr("--config needs a value");
 173         config_text= arg;
 174       } else if (!strcmp(arg,"--debug")) {
 175         initflags |= adns_if_debug;
 176       } else if (!strcmp(arg,"--help")) {
 177         usage(); quitnow(0);
 178       } else if (!strcmp(arg,"--version")) {
 179         VERSION_PRINT_QUIT("adnsresfilter"); quitnow(0);
 180       } else {
 181         usageerr("unknown long option");
 182       }
 183     } else {
 184       while ((c= *++arg)) {
 185         switch (c) {
 186         case 't':
 187           if (*++arg) settimeout(arg);
 188           else if ((arg= *++argv)) settimeout(arg);
 189           else usageerr("-t needs a value");
 190           forever= 0;
 191           arg= "\0";
 192           break;
 193         case 'w':
 194           forever= 1;
 195           break;
 196         case 'b':
 197           bracket= 1;
 198           break;
 199         case 'a':
 200           address= 1;
 201           break;
 202         case 'u':
 203           rrt= adns_r_ptr_raw;
 204           break;
 205         case 'h':
 206           usage();
 207           quitnow(0);
 208         default:
 209           usageerr("unknown short option");
 210         }
 211       }
 212     }
 213   }
 214 }
 215
 216 static void queueoutchar(int c) {
 217   struct outqueuenode *entry;
 218
 219   entry= outqueue.tail;
 220   if (!entry || entry->addr || entry->textlen >= peroutqueuenode) {
 221     peroutqueuenode= !peroutqueuenode || !entry || entry->addr ? 128 :
 222       peroutqueuenode >= 1024 ? 4096 : peroutqueuenode<<2;
 223     entry= xmalloc(sizeof(*entry));
 224     entry->buffer= xmalloc(peroutqueuenode);
 225     entry->textp= entry->buffer;
 226     entry->textlen= 0;
 227     entry->addr= 0;
 228     LIST_LINK_TAIL(outqueue,entry);
 229     outqueuelen++;
 230   }
 231   entry->textp[entry->textlen++]= c;
 232 }
 233
 234 static void queueoutstr(const char *str, int len) {
 235   while (len-- > 0) queueoutchar(*str++);
 236 }
 237
 238 static void writestdout(struct outqueuenode *entry) {
 239   int r;
 240
 241   while (entry->textlen) {
 242     r= write(1, entry->textp, entry->textlen);
 243     if (r < 0) {
 244       if (errno == EINTR) continue;
 245       if (errno == EAGAIN) { outblocked= 1; break; }
 246       sysfail("write stdout");
 247     }
 248     assert(r <= entry->textlen);
 249     entry->textp += r;
 250     entry->textlen -= r;
 251   }
 252   if (!entry->textlen) {
 253     LIST_UNLINK(outqueue,entry);
 254     free(entry->buffer);
 255     free(entry);
 256     outqueuelen--;
 257   }
 258 }
 259
 260 static void replacetextwithname(struct outqueuenode *entry) {
 261   char *name, *newbuf;
 262   int namelen, newlen;
 263
 264   name= entry->addr->ans->rrs.str[0];
 265   namelen= strlen(name);
 266   if (!address) {
 267     free(entry->buffer);
 268     entry->buffer= 0;
 269     entry->textp= name;
 270     entry->textlen= namelen;
 271   } else {
 272     newlen= entry->textlen + namelen + (bracket ? 0 : 2);
 273     newbuf= xmalloc(newlen + 1);
 274     sprintf(newbuf, bracket ? "%s%.*s" : "%s[%.*s]", name, entry->textlen, entry->textp);
 275     free(entry->buffer);
 276     entry->buffer= entry->textp= newbuf;
 277     entry->textlen= newlen;
 278   }
 279 }
 280
 281 static void checkadnsqueries(void) {
 282   adns_query qu;
 283   adns_answer *ans;
 284   void *context;
 285   struct treething *foundthing;
 286   int r;
 287
 288   for (;;) {
 289     qu= 0; context= 0; ans= 0;
 290     r= adns_check(ads,&qu,&ans,&context);
 291     if (r == ESRCH || r == EAGAIN) break;
 292     assert(!r);
 293     foundthing= context;
 294     foundthing->ans= ans;
 295     foundthing->qu= 0;
 296   }
 297 }
 298
 299 static void restartbuf(void) {
 300   if (inbuf>0) queueoutstr(addrtextbuf,inbuf);
 301   inbuf= 0;
 302 }
 303
 304 static int comparer(const void *a, const void *b) {
 305   return memcmp(a,b,4);
 306 }
 307
 308 static void procaddr(void) {
 309   struct treething *foundthing;
 310   void **searchfound;
 311   struct outqueuenode *entry;
 312   int r;
 313
 314   if (!newthing) {
 315     newthing= xmalloc(sizeof(struct treething));
 316     newthing->qu= 0;
 317     newthing->ans= 0;
 318   }
 319
 320   memcpy(newthing->bytes,bytes,4);
 321   searchfound= tsearch(newthing,&treeroot,comparer);
 322   if (!searchfound) sysfail("tsearch");
 323   foundthing= *searchfound;
 324
 325   if (foundthing == newthing) {
 326     newthing= 0;
 327     memcpy(&sa.sin_addr,bytes,4);
 328     r= adns_submit_reverse(ads, (const struct sockaddr*)&sa,
 329                            rrt,0,foundthing,&foundthing->qu);
 330     if (r) adnsfail("submit",r);
 331   }
 332   entry= xmalloc(sizeof(*entry));
 333   entry->buffer= xmalloc(inbuf);
 334   entry->textp= entry->buffer;
 335   memcpy(entry->textp,addrtextbuf,inbuf);
 336   entry->textlen= inbuf;
 337   entry->addr= foundthing;
 338   entry->printbefore= printbefore;
 339   LIST_LINK_TAIL(outqueue,entry);
 340   outqueuelen++;
 341   inbuf= 0;
 342   cbyte= -1;
 343 }
 344
 345 static void startaddr(void) {
 346   bytes[cbyte=0]= 0;
 347   inbyte= 0;
 348 }
 349
 350 static void readstdin(void) {
 351   char readbuf[512], *p;
 352   int r, c, nbyte;
 353
 354   while ((r= read(0,readbuf,sizeof(readbuf))) <= 0) {
 355     if (r == 0) { inputeof= 1; return; }
 356     if (r == EAGAIN) return;
 357     if (r != EINTR) sysfail("read stdin");
 358   }
 359   for (p=readbuf; r>0; r--,p++) {
 360     c= *p;
 361     if (cbyte==-1 && bracket && c=='[') {
 362       addrtextbuf[inbuf++]= c;
 363       startaddr();
 364     } else if (cbyte==-1 && !bracket && !isalnum(c)) {
 365       queueoutchar(c);
 366       startaddr();
 367     } else if (cbyte>=0 && inbyte<3 && c>='0' && c<='9' &&
 368                (nbyte= bytes[cbyte]*10 + (c-'0')) <= 255) {
 369       bytes[cbyte]= nbyte;
 370       addrtextbuf[inbuf++]= c;
 371       inbyte++;
 372     } else if (cbyte>=0 && cbyte<3 && inbyte>0 && c=='.') {
 373       bytes[++cbyte]= 0;
 374       addrtextbuf[inbuf++]= c;
 375       inbyte= 0;
 376     } else if (cbyte==3 && inbyte>0 && bracket && c==']') {
 377       addrtextbuf[inbuf++]= c;
 378       procaddr();
 379     } else if (cbyte==3 && inbyte>0 && !bracket && !isalnum(c)) {
 380       procaddr();
 381       queueoutchar(c);
 382       startaddr();
 383     } else {
 384       restartbuf();
 385       queueoutchar(c);
 386       cbyte= -1;
 387       if (!bracket && !isalnum(c)) startaddr();
 388     }
 389   }
 390 }
 391
 392 static void startup(void) {
 393   int r;
 394
 395   if (nonblock(0,1)) sysfail("set stdin to nonblocking mode");
 396   if (nonblock(1,1)) sysfail("set stdout to nonblocking mode");
 397   memset(&sa,0,sizeof(sa));
 398   sa.sin_family= AF_INET;
 399   if (config_text) {
 400     r= adns_init_strcfg(&ads,initflags,stderr,config_text);
 401   } else {
 402     r= adns_init(&ads,initflags,0);
 403   }
 404   if (r) adnsfail("init",r);
 405   cbyte= -1;
 406   inbyte= -1;
 407   inbuf= 0;
 408   if (!bracket) startaddr();
 409 }
 410
 411 int main(int argc, const char *const *argv) {
 412   int r, maxfd;
 413   fd_set readfds, writefds, exceptfds;
 414   struct outqueuenode *entry;
 415   struct timeval *tv, tvbuf, now;
 416
 417   parseargs(argv);
 418   startup();
 419
 420   while (!inputeof || outqueue.head) {
 421     maxfd= 2;
 422     tv= 0;
 423     FD_ZERO(&readfds); FD_ZERO(&writefds); FD_ZERO(&exceptfds);
 424     if ((entry= outqueue.head) && !outblocked) {
 425       if (!entry->addr) {
 426         writestdout(entry);
 427         continue;
 428       }
 429       if (entry->addr->ans) {
 430         if (entry->addr->ans->nrrs)
 431           replacetextwithname(entry);
 432         entry->addr= 0;
 433         continue;
 434       }
 435       r= gettimeofday(&now,0);  if (r) sysfail("gettimeofday");
 436       if (forever) {
 437         tv= 0;
 438       } else if (!timercmp(&now,&entry->printbefore,<)) {
 439         entry->addr= 0;
 440         continue;
 441       } else {
 442         tvbuf.tv_sec= entry->printbefore.tv_sec - now.tv_sec - 1;
 443         tvbuf.tv_usec= entry->printbefore.tv_usec - now.tv_usec + 1000000;
 444         tvbuf.tv_sec += tvbuf.tv_usec / 1000000;
 445         tvbuf.tv_usec %= 1000000;
 446         tv= &tvbuf;
 447       }
 448       adns_beforeselect(ads,&maxfd,&readfds,&writefds,&exceptfds,
 449                         &tv,&tvbuf,&now);
 450     }
 451     if (outblocked) FD_SET(1,&writefds);
 452     if (!inputeof && outqueuelen<1024) FD_SET(0,&readfds);
 453
 454     r= select(maxfd,&readfds,&writefds,&exceptfds,tv);
 455     if (r < 0) { if (r == EINTR) continue; else sysfail("select"); }
 456
 457     r= gettimeofday(&now,0);  if (r) sysfail("gettimeofday");
 458     adns_afterselect(ads,maxfd,&readfds,&writefds,&exceptfds,&now);
 459     checkadnsqueries();
 460
 461     if (FD_ISSET(0,&readfds)) {
 462       if (!forever) {
 463         printbefore= now;
 464         timevaladd(&printbefore,timeout);
 465       }
 466       readstdin();
 467     } else if (FD_ISSET(1,&writefds)) {
 468       outblocked= 0;
 469     }
 470   }
 471   if (nonblock(0,0)) sysfail("un-nonblock stdin");
 472   if (nonblock(1,0)) sysfail("un-nonblock stdout");
 473   adns_finish(ads);
 474   exit(0);
 475 }