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) 2014  Mark Wooding
   9  *    Copyright (C) 1999-2000,2003,2006  Tony Finch
  10  *    Copyright (C) 1991 Massachusetts Institute of Technology
  11  *  (See the file INSTALL for full details.)
  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 3, 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  */
  26
  27 #include <stdio.h>
  28 #include <stdlib.h>
  29 #include <string.h>
  30 #include <errno.h>
  31 #include <search.h>
  32 #include <assert.h>
  33 #include <ctype.h>
  34
  35 #include <sys/types.h>
  36 #include <unistd.h>
  37 #include <fcntl.h>
  38
  39 #include "config.h"
  40 #include "adns.h"
  41 #include "dlist.h"
  42 #include "tvarith.h"
  43 #include "client.h"
  44
  45 #ifdef ADNS_REGRESS_TEST
  46 # include "hredirect.h"
  47 #endif
  48
  49 struct outqueuenode {
  50   struct outqueuenode *next, *back;
  51   char *buffer, *textp;
  52   int textlen;
  53   struct timeval printbefore;
  54   struct treething *addr;
  55 };
  56
  57 static int bracket, forever, address;
  58 static unsigned long timeout= 1000;
  59 static adns_rrtype rrt= adns_r_ptr;
  60 static adns_initflags initflags= 0;
  61 static const char *config_text;
  62
  63 static int outblocked, inputeof;
  64 static struct { struct outqueuenode *head, *tail; } outqueue;
  65 static int peroutqueuenode, outqueuelen;
  66
  67 static struct sockaddr_in sa;
  68 static adns_state ads;
  69
  70 static char addrtextbuf[14];
  71 static int cbyte, inbyte, inbuf;
  72 static unsigned char bytes[4];
  73 static struct timeval printbefore;
  74
  75 struct treething {
  76   unsigned char bytes[4];
  77   adns_query qu;
  78   adns_answer *ans;
  79 };
  80
  81 static struct treething *newthing;
  82 static void *treeroot;
  83
  84 static int nonblock(int fd, int isnonblock) {
  85   int r;
  86
  87   r= fcntl(fd,F_GETFL);
  88   if (r==-1) return -1;
  89   r= fcntl(fd,F_SETFL, isnonblock ? r|O_NONBLOCK : r&~O_NONBLOCK);
  90   if (r==-1) return -1;
  91   return 0;
  92 }
  93
  94 void quitnow(int exitstatus) {
  95   nonblock(0,0);
  96   nonblock(1,0);
  97   exit(exitstatus);
  98 }
  99
 100 static void sysfail(const char *what) NONRETURNING;
 101 static void sysfail(const char *what) {
 102   fprintf(stderr,"adnsresfilter: system call failed: %s: %s\n",what,strerror(errno));
 103   quitnow(2);
 104 }
 105
 106 static void *xmalloc(size_t sz) {
 107   void *r;
 108   r= malloc(sz);  if (r) return r;
 109   sysfail("malloc");
 110 }
 111
 112 static void outputerr(void) NONRETURNING;
 113 static void outputerr(void) { sysfail("write to stdout"); }
 114
 115 static void usage(void) {
 116   if (printf("usage: adnsresfilter [<options ...>]\n"
 117              "       adnsresfilter  -h|--help | --version\n"
 118              "options: -t<milliseconds>|--timeout <milliseconds>\n"
 119              "         -w|--wait        (always wait for queries to time out or fail)\n"
 120              "         -b|--brackets    (require [...] around IP addresses)\n"
 121              "         -a|--address     (always include [address] in output)\n"
 122              "         -u|--unchecked   (do not forward map for checking)\n"
 123              "         --config <text>  (use this instead of resolv.conf)\n"
 124              "         --debug          (turn on adns resolver debugging)\n"
 125              "Timeout is the maximum amount to delay any particular bit of output for.\n"
 126              "Lookups will go on in the background.  Default timeout = 1000 (ms).\n")
 127       == EOF) outputerr();
 128   if (fflush(stdout)) sysfail("flush stdout");
 129 }
 130
 131 static void usageerr(const char *why) NONRETURNING;
 132 static void usageerr(const char *why) {
 133   fprintf(stderr,"adnsresfilter: bad usage: %s\n",why);
 134   usage();
 135   quitnow(1);
 136 }
 137
 138 static void adnsfail(const char *what, int e) NONRETURNING;
 139 static void adnsfail(const char *what, int e) {
 140   fprintf(stderr,"adnsresfilter: adns call failed: %s: %s\n",what,strerror(e));
 141   quitnow(2);
 142 }
 143
 144 static void settimeout(const char *arg) {
 145   char *ep;
 146   timeout= strtoul(arg,&ep,0);
 147   if (*ep) usageerr("invalid timeout");
 148 }
 149
 150 static void parseargs(const char *const *argv) {
 151   const char *arg;
 152   int c;
 153
 154   while ((arg= *++argv)) {
 155     if (arg[0] != '-') usageerr("no non-option arguments are allowed");
 156     if (arg[1] == '-') {
 157       if (!strcmp(arg,"--timeout")) {
 158         if (!(arg= *++argv)) usageerr("--timeout needs a value");
 159         settimeout(arg);
 160         forever= 0;
 161       } else if (!strcmp(arg,"--wait")) {
 162         forever= 1;
 163       } else if (!strcmp(arg,"--brackets")) {
 164         bracket= 1;
 165       } else if (!strcmp(arg,"--address")) {
 166         address= 1;
 167       } else if (!strcmp(arg,"--unchecked")) {
 168         rrt= adns_r_ptr_raw;
 169       } else if (!strcmp(arg,"--config")) {
 170         if (!(arg= *++argv)) usageerr("--config needs a value");
 171         config_text= arg;
 172       } else if (!strcmp(arg,"--debug")) {
 173         initflags |= adns_if_debug;
 174       } else if (!strcmp(arg,"--help")) {
 175         usage(); quitnow(0);
 176       } else if (!strcmp(arg,"--version")) {
 177         VERSION_PRINT_QUIT("adnsresfilter"); quitnow(0);
 178       } else {
 179         usageerr("unknown long option");
 180       }
 181     } else {
 182       while ((c= *++arg)) {
 183         switch (c) {
 184         case 't':
 185           if (*++arg) settimeout(arg);
 186           else if ((arg= *++argv)) settimeout(arg);
 187           else usageerr("-t needs a value");
 188           forever= 0;
 189           arg= "\0";
 190           break;
 191         case 'w':
 192           forever= 1;
 193           break;
 194         case 'b':
 195           bracket= 1;
 196           break;
 197         case 'a':
 198           address= 1;
 199           break;
 200         case 'u':
 201           rrt= adns_r_ptr_raw;
 202           break;
 203         case 'h':
 204           usage();
 205           quitnow(0);
 206         default:
 207           usageerr("unknown short option");
 208         }
 209       }
 210     }
 211   }
 212 }
 213
 214 static void queueoutchar(int c) {
 215   struct outqueuenode *entry;
 216
 217   entry= outqueue.tail;
 218   if (!entry || entry->addr ||
 219       entry->textlen >= peroutqueuenode - (entry->textp - entry->buffer)) {
 220     peroutqueuenode= !peroutqueuenode || !entry || entry->addr ? 128 :
 221       peroutqueuenode >= 1024 ? 4096 : peroutqueuenode<<2;
 222     entry= xmalloc(sizeof(*entry));
 223     entry->buffer= xmalloc(peroutqueuenode);
 224     entry->textp= entry->buffer;
 225     entry->textlen= 0;
 226     entry->addr= 0;
 227     LIST_LINK_TAIL(outqueue,entry);
 228     outqueuelen++;
 229   }
 230   entry->textp[entry->textlen++]= c;
 231 }
 232
 233 static void queueoutstr(const char *str, int len) {
 234   while (len-- > 0) queueoutchar(*str++);
 235 }
 236
 237 static void writestdout(struct outqueuenode *entry) {
 238   int r;
 239
 240   while (entry->textlen) {
 241     r= write(1, entry->textp, entry->textlen);
 242     if (r < 0) {
 243       if (errno == EINTR) continue;
 244       if (errno == EAGAIN) { outblocked= 1; break; }
 245       sysfail("write stdout");
 246     }
 247     assert(r <= entry->textlen);
 248     entry->textp += r;
 249     entry->textlen -= r;
 250   }
 251   if (!entry->textlen) {
 252     LIST_UNLINK(outqueue,entry);
 253     free(entry->buffer);
 254     free(entry);
 255     outqueuelen--;
 256   }
 257 }
 258
 259 static void replacetextwithname(struct outqueuenode *entry) {
 260   char *name, *newbuf;
 261   int namelen, newlen;
 262
 263   name= entry->addr->ans->rrs.str[0];
 264   namelen= strlen(name);
 265   if (!address) {
 266     free(entry->buffer);
 267     entry->buffer= 0;
 268     entry->textp= name;
 269     entry->textlen= namelen;
 270   } else {
 271     newlen= entry->textlen + namelen + (bracket ? 0 : 2);
 272     newbuf= xmalloc(newlen + 1);
 273     sprintf(newbuf, bracket ? "%s%.*s" : "%s[%.*s]", name, entry->textlen, entry->textp);
 274     free(entry->buffer);
 275     entry->buffer= entry->textp= newbuf;
 276     entry->textlen= newlen;
 277   }
 278 }
 279
 280 static void checkadnsqueries(void) {
 281   adns_query qu;
 282   adns_answer *ans;
 283   void *context;
 284   struct treething *foundthing;
 285   int r;
 286
 287   for (;;) {
 288     qu= 0; context= 0; ans= 0;
 289     r= adns_check(ads,&qu,&ans,&context);
 290     if (r == ESRCH || r == EAGAIN) break;
 291     assert(!r);
 292     foundthing= context;
 293     foundthing->ans= ans;
 294     foundthing->qu= 0;
 295   }
 296 }
 297
 298 static void restartbuf(void) {
 299   if (inbuf>0) queueoutstr(addrtextbuf,inbuf);
 300   inbuf= 0;
 301 }
 302
 303 static int comparer(const void *a, const void *b) {
 304   return memcmp(a,b,4);
 305 }
 306
 307 static void procaddr(void) {
 308   struct treething *foundthing;
 309   void **searchfound;
 310   struct outqueuenode *entry;
 311   int r;
 312
 313   if (!newthing) {
 314     newthing= xmalloc(sizeof(struct treething));
 315     newthing->qu= 0;
 316     newthing->ans= 0;
 317   }
 318
 319   memcpy(newthing->bytes,bytes,4);
 320   searchfound= tsearch(newthing,&treeroot,comparer);
 321   if (!searchfound) sysfail("tsearch");
 322   foundthing= *searchfound;
 323
 324   if (foundthing == newthing) {
 325     newthing= 0;
 326     memcpy(&sa.sin_addr,bytes,4);
 327     r= adns_submit_reverse(ads, (const struct sockaddr*)&sa,
 328                            rrt,0,foundthing,&foundthing->qu);
 329     if (r) adnsfail("submit",r);
 330   }
 331   entry= xmalloc(sizeof(*entry));
 332   entry->buffer= xmalloc(inbuf);
 333   entry->textp= entry->buffer;
 334   memcpy(entry->textp,addrtextbuf,inbuf);
 335   entry->textlen= inbuf;
 336   entry->addr= foundthing;
 337   entry->printbefore= printbefore;
 338   LIST_LINK_TAIL(outqueue,entry);
 339   outqueuelen++;
 340   inbuf= 0;
 341   cbyte= -1;
 342 }
 343
 344 static void startaddr(void) {
 345   bytes[cbyte=0]= 0;
 346   inbyte= 0;
 347 }
 348
 349 static void readstdin(void) {
 350   char readbuf[512], *p;
 351   int r, c, nbyte;
 352
 353   while ((r= read(0,readbuf,sizeof(readbuf))) <= 0) {
 354     if (r == 0) { inputeof= 1; return; }
 355     if (r == EAGAIN) return;
 356     if (r != EINTR) sysfail("read stdin");
 357   }
 358   for (p=readbuf; r>0; r--,p++) {
 359     c= *p;
 360     if (cbyte==-1 && bracket && c=='[') {
 361       addrtextbuf[inbuf++]= c;
 362       startaddr();
 363     } else if (cbyte==-1 && !bracket && !isalnum(c)) {
 364       queueoutchar(c);
 365       startaddr();
 366     } else if (cbyte>=0 && inbyte<3 && c>='0' && c<='9' &&
 367                (nbyte= bytes[cbyte]*10 + (c-'0')) <= 255) {
 368       bytes[cbyte]= nbyte;
 369       addrtextbuf[inbuf++]= c;
 370       inbyte++;
 371     } else if (cbyte>=0 && cbyte<3 && inbyte>0 && c=='.') {
 372       bytes[++cbyte]= 0;
 373       addrtextbuf[inbuf++]= c;
 374       inbyte= 0;
 375     } else if (cbyte==3 && inbyte>0 && bracket && c==']') {
 376       addrtextbuf[inbuf++]= c;
 377       procaddr();
 378     } else if (cbyte==3 && inbyte>0 && !bracket && !isalnum(c)) {
 379       procaddr();
 380       queueoutchar(c);
 381       startaddr();
 382     } else {
 383       restartbuf();
 384       queueoutchar(c);
 385       cbyte= -1;
 386       if (!bracket && !isalnum(c)) startaddr();
 387     }
 388   }
 389 }
 390
 391 static void startup(void) {
 392   int r;
 393
 394   if (nonblock(0,1)) sysfail("set stdin to nonblocking mode");
 395   if (nonblock(1,1)) sysfail("set stdout to nonblocking mode");
 396   memset(&sa,0,sizeof(sa));
 397   sa.sin_family= AF_INET;
 398   if (config_text) {
 399     r= adns_init_strcfg(&ads,initflags,stderr,config_text);
 400   } else {
 401     r= adns_init(&ads,initflags,0);
 402   }
 403   if (r) adnsfail("init",r);
 404   cbyte= -1;
 405   inbyte= -1;
 406   inbuf= 0;
 407   if (!bracket) startaddr();
 408 }
 409
 410 int main(int argc, const char *const *argv) {
 411   int r, maxfd;
 412   fd_set readfds, writefds, exceptfds;
 413   struct outqueuenode *entry;
 414   struct timeval *tv, tvbuf, now;
 415
 416   parseargs(argv);
 417   startup();
 418
 419   while (!inputeof || outqueue.head) {
 420     maxfd= 2;
 421     tv= 0;
 422     FD_ZERO(&readfds); FD_ZERO(&writefds); FD_ZERO(&exceptfds);
 423     if ((entry= outqueue.head) && !outblocked) {
 424       if (!entry->addr) {
 425         writestdout(entry);
 426         continue;
 427       }
 428       if (entry->addr->ans) {
 429         if (entry->addr->ans->nrrs)
 430           replacetextwithname(entry);
 431         entry->addr= 0;
 432         continue;
 433       }
 434       r= gettimeofday(&now,0);  if (r) sysfail("gettimeofday");
 435       if (forever) {
 436         tv= 0;
 437       } else if (!timercmp(&now,&entry->printbefore,<)) {
 438         entry->addr= 0;
 439         continue;
 440       } else {
 441         tvbuf.tv_sec= entry->printbefore.tv_sec - now.tv_sec - 1;
 442         tvbuf.tv_usec= entry->printbefore.tv_usec - now.tv_usec + 1000000;
 443         tvbuf.tv_sec += tvbuf.tv_usec / 1000000;
 444         tvbuf.tv_usec %= 1000000;
 445         tv= &tvbuf;
 446       }
 447       adns_beforeselect(ads,&maxfd,&readfds,&writefds,&exceptfds,
 448                         &tv,&tvbuf,&now);
 449     }
 450     if (outblocked) FD_SET(1,&writefds);
 451     if (!inputeof && outqueuelen<1024) FD_SET(0,&readfds);
 452
 453     r= select(maxfd,&readfds,&writefds,&exceptfds,tv);
 454     if (r < 0) { if (r == EINTR) continue; else sysfail("select"); }
 455
 456     r= gettimeofday(&now,0);  if (r) sysfail("gettimeofday");
 457     adns_afterselect(ads,maxfd,&readfds,&writefds,&exceptfds,&now);
 458     checkadnsqueries();
 459
 460     if (FD_ISSET(0,&readfds)) {
 461       if (!forever) {
 462         printbefore= now;
 463         timevaladd(&printbefore,timeout);
 464       }
 465       readstdin();
 466     } else if (FD_ISSET(1,&writefds)) {
 467       outblocked= 0;
 468     }
 469   }
 470   if (nonblock(0,0)) sysfail("un-nonblock stdin");
 471   if (nonblock(1,0)) sysfail("un-nonblock stdout");
 472   adns_finish(ads);
 473   exit(0);
 474 }