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 part of adns, which is
   7  *    Copyright (C) 1997-2000,2003,2006,2014  Ian Jackson
   8  *    Copyright (C) 1999-2000,2003,2006  Tony Finch
   9  *    Copyright (C) 1991 Massachusetts Institute of Technology
  10  *  (See the file INSTALL for full details.)
  11  *
  12  *  This program is free software; you can redistribute it and/or modify
  13  *  it under the terms of the GNU General Public License as published by
  14  *  the Free Software Foundation; either version 3, or (at your option)
  15  *  any later version.
  16  *
  17  *  This program is distributed in the hope that it will be useful,
  18  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  *  GNU General Public License for more details.
  21  *
  22  *  You should have received a copy of the GNU General Public License
  23  *  along with this program; if not, write to the Free Software Foundation.
  24  */
  25
  26 #include <stdio.h>
  27 #include <stdlib.h>
  28 #include <string.h>
  29 #include <errno.h>
  30 #include <search.h>
  31 #include <assert.h>
  32 #include <ctype.h>
  33
  34 #include <sys/types.h>
  35 #include <unistd.h>
  36 #include <fcntl.h>
  37
  38 #include "config.h"
  39 #include "adns.h"
  40 #include "dlist.h"
  41 #include "tvarith.h"
  42 #include "client.h"
  43
  44 #ifdef ADNS_REGRESS_TEST
  45 # include "hredirect.h"
  46 #endif
  47
  48 struct outqueuenode {
  49   struct outqueuenode *next, *back;
  50   char *buffer, *textp;
  51   int textlen;
  52   struct timeval printbefore;
  53   struct treething *addr;
  54 };
  55
  56 static int bracket, forever, address;
  57 static unsigned long timeout= 1000;
  58 static adns_rrtype rrt= adns_r_ptr;
  59 static adns_initflags initflags= 0;
  60 static const char *config_text;
  61
  62 static int outblocked, inputeof;
  63 static struct { struct outqueuenode *head, *tail; } outqueue;
  64 static int peroutqueuenode, outqueuelen;
  65
  66 static struct sockaddr_in sa;
  67 static adns_state ads;
  68
  69 static char addrtextbuf[14];
  70 static int cbyte, inbyte, inbuf;
  71 static unsigned char bytes[4];
  72 static struct timeval printbefore;
  73
  74 struct treething {
  75   unsigned char bytes[4];
  76   adns_query qu;
  77   adns_answer *ans;
  78 };
  79
  80 static struct treething *newthing;
  81 static void *treeroot;
  82
  83 static int nonblock(int fd, int isnonblock) {
  84   int r;
  85
  86   r= fcntl(fd,F_GETFL);
  87   if (r==-1) return -1;
  88   r= fcntl(fd,F_SETFL, isnonblock ? r|O_NONBLOCK : r&~O_NONBLOCK);
  89   if (r==-1) return -1;
  90   return 0;
  91 }
  92
  93 void quitnow(int exitstatus) {
  94   nonblock(0,0);
  95   nonblock(1,0);
  96   exit(exitstatus);
  97 }
  98
  99 static void sysfail(const char *what) NONRETURNING;
 100 static void sysfail(const char *what) {
 101   fprintf(stderr,"adnsresfilter: system call failed: %s: %s\n",what,strerror(errno));
 102   quitnow(2);
 103 }
 104
 105 static void *xmalloc(size_t sz) {
 106   void *r;
 107   r= malloc(sz);  if (r) return r;
 108   sysfail("malloc");
 109 }
 110
 111 static void outputerr(void) NONRETURNING;
 112 static void outputerr(void) { sysfail("write to stdout"); }
 113
 114 static void usage(void) {
 115   if (printf("usage: adnsresfilter [<options ...>]\n"
 116              "       adnsresfilter  -h|--help | --version\n"
 117              "options: -t<milliseconds>|--timeout <milliseconds>\n"
 118              "         -w|--wait        (always wait for queries to time out or fail)\n"
 119              "         -b|--brackets    (require [...] around IP addresses)\n"
 120              "         -a|--address     (always include [address] in output)\n"
 121              "         -u|--unchecked   (do not forward map for checking)\n"
 122              "         --config <text>  (use this instead of resolv.conf)\n"
 123              "         --debug          (turn on adns resolver debugging)\n"
 124              "Timeout is the maximum amount to delay any particular bit of output for.\n"
 125              "Lookups will go on in the background.  Default timeout = 1000 (ms).\n")
 126       == EOF) outputerr();
 127   if (fflush(stdout)) sysfail("flush stdout");
 128 }
 129
 130 static void usageerr(const char *why) NONRETURNING;
 131 static void usageerr(const char *why) {
 132   fprintf(stderr,"adnsresfilter: bad usage: %s\n",why);
 133   usage();
 134   quitnow(1);
 135 }
 136
 137 static void adnsfail(const char *what, int e) NONRETURNING;
 138 static void adnsfail(const char *what, int e) {
 139   fprintf(stderr,"adnsresfilter: adns call failed: %s: %s\n",what,strerror(e));
 140   quitnow(2);
 141 }
 142
 143 static void settimeout(const char *arg) {
 144   char *ep;
 145   timeout= strtoul(arg,&ep,0);
 146   if (*ep) usageerr("invalid timeout");
 147 }
 148
 149 static void parseargs(const char *const *argv) {
 150   const char *arg;
 151   int c;
 152
 153   while ((arg= *++argv)) {
 154     if (arg[0] != '-') usageerr("no non-option arguments are allowed");
 155     if (arg[1] == '-') {
 156       if (!strcmp(arg,"--timeout")) {
 157         if (!(arg= *++argv)) usageerr("--timeout needs a value");
 158         settimeout(arg);
 159         forever= 0;
 160       } else if (!strcmp(arg,"--wait")) {
 161         forever= 1;
 162       } else if (!strcmp(arg,"--brackets")) {
 163         bracket= 1;
 164       } else if (!strcmp(arg,"--address")) {
 165         address= 1;
 166       } else if (!strcmp(arg,"--unchecked")) {
 167         rrt= adns_r_ptr_raw;
 168       } else if (!strcmp(arg,"--config")) {
 169         if (!(arg= *++argv)) usageerr("--config needs a value");
 170         config_text= arg;
 171       } else if (!strcmp(arg,"--debug")) {
 172         initflags |= adns_if_debug;
 173       } else if (!strcmp(arg,"--help")) {
 174         usage(); quitnow(0);
 175       } else if (!strcmp(arg,"--version")) {
 176         VERSION_PRINT_QUIT("adnsresfilter"); quitnow(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           quitnow(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 ||
 218       entry->textlen >= peroutqueuenode - (entry->textp - entry->buffer)) {
 219     peroutqueuenode= !peroutqueuenode || !entry || entry->addr ? 128 :
 220       peroutqueuenode >= 1024 ? 4096 : peroutqueuenode<<2;
 221     entry= xmalloc(sizeof(*entry));
 222     entry->buffer= xmalloc(peroutqueuenode);
 223     entry->textp= entry->buffer;
 224     entry->textlen= 0;
 225     entry->addr= 0;
 226     LIST_LINK_TAIL(outqueue,entry);
 227     outqueuelen++;
 228   }
 229   entry->textp[entry->textlen++]= c;
 230 }
 231
 232 static void queueoutstr(const char *str, int len) {
 233   while (len-- > 0) queueoutchar(*str++);
 234 }
 235
 236 static void writestdout(struct outqueuenode *entry) {
 237   int r;
 238
 239   while (entry->textlen) {
 240     r= write(1, entry->textp, entry->textlen);
 241     if (r < 0) {
 242       if (errno == EINTR) continue;
 243       if (errno == EAGAIN) { outblocked= 1; break; }
 244       sysfail("write stdout");
 245     }
 246     assert(r <= entry->textlen);
 247     entry->textp += r;
 248     entry->textlen -= r;
 249   }
 250   if (!entry->textlen) {
 251     LIST_UNLINK(outqueue,entry);
 252     free(entry->buffer);
 253     free(entry);
 254     outqueuelen--;
 255   }
 256 }
 257
 258 static void replacetextwithname(struct outqueuenode *entry) {
 259   char *name, *newbuf;
 260   int namelen, newlen;
 261
 262   name= entry->addr->ans->rrs.str[0];
 263   namelen= strlen(name);
 264   if (!address) {
 265     free(entry->buffer);
 266     entry->buffer= 0;
 267     entry->textp= name;
 268     entry->textlen= namelen;
 269   } else {
 270     newlen= entry->textlen + namelen + (bracket ? 0 : 2);
 271     newbuf= xmalloc(newlen + 1);
 272     sprintf(newbuf, bracket ? "%s%.*s" : "%s[%.*s]", name, entry->textlen, entry->textp);
 273     free(entry->buffer);
 274     entry->buffer= entry->textp= newbuf;
 275     entry->textlen= newlen;
 276   }
 277 }
 278
 279 static void checkadnsqueries(void) {
 280   adns_query qu;
 281   adns_answer *ans;
 282   void *context;
 283   struct treething *foundthing;
 284   int r;
 285
 286   for (;;) {
 287     qu= 0; context= 0; ans= 0;
 288     r= adns_check(ads,&qu,&ans,&context);
 289     if (r == ESRCH || r == EAGAIN) break;
 290     assert(!r);
 291     foundthing= context;
 292     foundthing->ans= ans;
 293     foundthing->qu= 0;
 294   }
 295 }
 296
 297 static void restartbuf(void) {
 298   if (inbuf>0) queueoutstr(addrtextbuf,inbuf);
 299   inbuf= 0;
 300 }
 301
 302 static int comparer(const void *a, const void *b) {
 303   return memcmp(a,b,4);
 304 }
 305
 306 static void procaddr(void) {
 307   struct treething *foundthing;
 308   void **searchfound;
 309   struct outqueuenode *entry;
 310   int r;
 311
 312   if (!newthing) {
 313     newthing= xmalloc(sizeof(struct treething));
 314     newthing->qu= 0;
 315     newthing->ans= 0;
 316   }
 317
 318   memcpy(newthing->bytes,bytes,4);
 319   searchfound= tsearch(newthing,&treeroot,comparer);
 320   if (!searchfound) sysfail("tsearch");
 321   foundthing= *searchfound;
 322
 323   if (foundthing == newthing) {
 324     newthing= 0;
 325     memcpy(&sa.sin_addr,bytes,4);
 326     r= adns_submit_reverse(ads, (const struct sockaddr*)&sa,
 327                            rrt,0,foundthing,&foundthing->qu);
 328     if (r) adnsfail("submit",r);
 329   }
 330   entry= xmalloc(sizeof(*entry));
 331   entry->buffer= xmalloc(inbuf);
 332   entry->textp= entry->buffer;
 333   memcpy(entry->textp,addrtextbuf,inbuf);
 334   entry->textlen= inbuf;
 335   entry->addr= foundthing;
 336   entry->printbefore= printbefore;
 337   LIST_LINK_TAIL(outqueue,entry);
 338   outqueuelen++;
 339   inbuf= 0;
 340   cbyte= -1;
 341 }
 342
 343 static void startaddr(void) {
 344   bytes[cbyte=0]= 0;
 345   inbyte= 0;
 346 }
 347
 348 static void readstdin(void) {
 349   char readbuf[512], *p;
 350   int r, c, nbyte;
 351
 352   while ((r= read(0,readbuf,sizeof(readbuf))) <= 0) {
 353     if (r == 0) { inputeof= 1; return; }
 354     if (r == EAGAIN) return;
 355     if (r != EINTR) sysfail("read stdin");
 356   }
 357   for (p=readbuf; r>0; r--,p++) {
 358     c= *p;
 359     if (cbyte==-1 && bracket && c=='[') {
 360       addrtextbuf[inbuf++]= c;
 361       startaddr();
 362     } else if (cbyte==-1 && !bracket && !isalnum(c)) {
 363       queueoutchar(c);
 364       startaddr();
 365     } else if (cbyte>=0 && inbyte<3 && c>='0' && c<='9' &&
 366                (nbyte= bytes[cbyte]*10 + (c-'0')) <= 255) {
 367       bytes[cbyte]= nbyte;
 368       addrtextbuf[inbuf++]= c;
 369       inbyte++;
 370     } else if (cbyte>=0 && cbyte<3 && inbyte>0 && c=='.') {
 371       bytes[++cbyte]= 0;
 372       addrtextbuf[inbuf++]= c;
 373       inbyte= 0;
 374     } else if (cbyte==3 && inbyte>0 && bracket && c==']') {
 375       addrtextbuf[inbuf++]= c;
 376       procaddr();
 377     } else if (cbyte==3 && inbyte>0 && !bracket && !isalnum(c)) {
 378       procaddr();
 379       queueoutchar(c);
 380       startaddr();
 381     } else {
 382       restartbuf();
 383       queueoutchar(c);
 384       cbyte= -1;
 385       if (!bracket && !isalnum(c)) startaddr();
 386     }
 387   }
 388 }
 389
 390 static void startup(void) {
 391   int r;
 392
 393   if (nonblock(0,1)) sysfail("set stdin to nonblocking mode");
 394   if (nonblock(1,1)) sysfail("set stdout to nonblocking mode");
 395   memset(&sa,0,sizeof(sa));
 396   sa.sin_family= AF_INET;
 397   if (config_text) {
 398     r= adns_init_strcfg(&ads,initflags,stderr,config_text);
 399   } else {
 400     r= adns_init(&ads,initflags,0);
 401   }
 402   if (r) adnsfail("init",r);
 403   cbyte= -1;
 404   inbyte= -1;
 405   inbuf= 0;
 406   if (!bracket) startaddr();
 407 }
 408
 409 int main(int argc, const char *const *argv) {
 410   int r, maxfd;
 411   fd_set readfds, writefds, exceptfds;
 412   struct outqueuenode *entry;
 413   struct timeval *tv, tvbuf, now;
 414
 415   parseargs(argv);
 416   startup();
 417
 418   while (!inputeof || outqueue.head) {
 419     maxfd= 2;
 420     tv= 0;
 421     FD_ZERO(&readfds); FD_ZERO(&writefds); FD_ZERO(&exceptfds);
 422     if ((entry= outqueue.head) && !outblocked) {
 423       if (!entry->addr) {
 424         writestdout(entry);
 425         continue;
 426       }
 427       if (entry->addr->ans) {
 428         if (entry->addr->ans->nrrs)
 429           replacetextwithname(entry);
 430         entry->addr= 0;
 431         continue;
 432       }
 433       r= gettimeofday(&now,0);  if (r) sysfail("gettimeofday");
 434       if (forever) {
 435         tv= 0;
 436       } else if (!timercmp(&now,&entry->printbefore,<)) {
 437         entry->addr= 0;
 438         continue;
 439       } else {
 440         tvbuf.tv_sec= entry->printbefore.tv_sec - now.tv_sec - 1;
 441         tvbuf.tv_usec= entry->printbefore.tv_usec - now.tv_usec + 1000000;
 442         tvbuf.tv_sec += tvbuf.tv_usec / 1000000;
 443         tvbuf.tv_usec %= 1000000;
 444         tv= &tvbuf;
 445       }
 446       adns_beforeselect(ads,&maxfd,&readfds,&writefds,&exceptfds,
 447                         &tv,&tvbuf,&now);
 448     }
 449     if (outblocked) FD_SET(1,&writefds);
 450     if (!inputeof && outqueuelen<1024) FD_SET(0,&readfds);
 451
 452     r= select(maxfd,&readfds,&writefds,&exceptfds,tv);
 453     if (r < 0) { if (r == EINTR) continue; else sysfail("select"); }
 454
 455     r= gettimeofday(&now,0);  if (r) sysfail("gettimeofday");
 456     adns_afterselect(ads,maxfd,&readfds,&writefds,&exceptfds,&now);
 457     checkadnsqueries();
 458
 459     if (FD_ISSET(0,&readfds)) {
 460       if (!forever) {
 461         printbefore= now;
 462         timevaladd(&printbefore,timeout);
 463       }
 464       readstdin();
 465     } else if (FD_ISSET(1,&writefds)) {
 466       outblocked= 0;
 467     }
 468   }
 469   if (nonblock(0,0)) sysfail("un-nonblock stdin");
 470   if (nonblock(1,0)) sysfail("un-nonblock stdout");
 471   adns_finish(ads);
 472   exit(0);
 473 }