| 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 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 2, 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 | * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
| 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 | } |