1 /* dnsmasq is Copyright (c) 2000-2009 Simon Kelley 2 3 This program is free software; you can redistribute it and/or modify 4 it under the terms of the GNU General Public License as published by 5 the Free Software Foundation; version 2 dated June, 1991, or 6 (at your option) version 3 dated 29 June, 2007. 7 8 This program is distributed in the hope that it will be useful, 9 but WITHOUT ANY WARRANTY; without even the implied warranty of 10 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 11 GNU General Public License for more details. 12 13 You should have received a copy of the GNU General Public License 14 along with this program. If not, see <http://www.gnu.org/licenses/>. 15 */ 16 17 /* The SURF random number generator was taken from djbdns-1.05, by 18 Daniel J Bernstein, which is public domain. */ 19 20 21 #include "dnsmasq.h" 22 23 #ifdef HAVE_BROKEN_RTC 24 #include <sys/times.h> 25 #endif 26 27 #ifdef LOCALEDIR 28 #include <idna.h> 29 #endif 30 31 #ifdef HAVE_ARC4RANDOM 32 void rand_init(void) 33 { 34 return; 35 } 36 37 unsigned short rand16(void) 38 { 39 return (unsigned short) (arc4random() >> 15); 40 } 41 42 #else 43 44 /* SURF random number generator */ 45 46 typedef unsigned int uint32; 47 48 static uint32 seed[32]; 49 static uint32 in[12]; 50 static uint32 out[8]; 51 52 void rand_init() 53 { 54 int fd = open(RANDFILE, O_RDONLY); 55 56 if (fd == -1 || 57 !read_write(fd, (unsigned char *)&seed, sizeof(seed), 1) || 58 !read_write(fd, (unsigned char *)&in, sizeof(in), 1)) 59 die(_("failed to seed the random number generator: %s"), NULL, EC_MISC); 60 61 close(fd); 62 } 63 64 #define ROTATE(x,b) (((x) << (b)) | ((x) >> (32 - (b)))) 65 #define MUSH(i,b) x = t[i] += (((x ^ seed[i]) + sum) ^ ROTATE(x,b)); 66 67 static void surf(void) 68 { 69 uint32 t[12]; uint32 x; uint32 sum = 0; 70 int r; int i; int loop; 71 72 for (i = 0;i < 12;++i) t[i] = in[i] ^ seed[12 + i]; 73 for (i = 0;i < 8;++i) out[i] = seed[24 + i]; 74 x = t[11]; 75 for (loop = 0;loop < 2;++loop) { 76 for (r = 0;r < 16;++r) { 77 sum += 0x9e3779b9; 78 MUSH(0,5) MUSH(1,7) MUSH(2,9) MUSH(3,13) 79 MUSH(4,5) MUSH(5,7) MUSH(6,9) MUSH(7,13) 80 MUSH(8,5) MUSH(9,7) MUSH(10,9) MUSH(11,13) 81 } 82 for (i = 0;i < 8;++i) out[i] ^= t[i + 4]; 83 } 84 } 85 86 unsigned short rand16(void) 87 { 88 static int outleft = 0; 89 90 if (!outleft) { 91 if (!++in[0]) if (!++in[1]) if (!++in[2]) ++in[3]; 92 surf(); 93 outleft = 8; 94 } 95 96 return (unsigned short) out[--outleft]; 97 } 98 99 #endif 100 101 static int check_name(char *in) 102 { 103 /* remove trailing . 104 also fail empty string and label > 63 chars */ 105 size_t dotgap = 0, l = strlen(in); 106 char c; 107 int nowhite = 0; 108 109 if (l == 0 || l > MAXDNAME) return 0; 110 111 if (in[l-1] == '.') 112 { 113 if (l == 1) return 0; 114 in[l-1] = 0; 115 } 116 117 for (; (c = *in); in++) 118 { 119 if (c == '.') 120 dotgap = 0; 121 else if (++dotgap > MAXLABEL) 122 return 0; 123 else if (isascii(c) && iscntrl(c)) 124 /* iscntrl only gives expected results for ascii */ 125 return 0; 126 #ifndef LOCALEDIR 127 else if (!isascii(c)) 128 return 0; 129 #endif 130 else if (c != ' ') 131 nowhite = 1; 132 } 133 134 if (!nowhite) 135 return 0; 136 137 return 1; 138 } 139 140 /* Hostnames have a more limited valid charset than domain names 141 so check for legal char a-z A-Z 0-9 - _ 142 Note that this may receive a FQDN, so only check the first label 143 for the tighter criteria. */ 144 int legal_hostname(char *name) 145 { 146 char c; 147 148 if (!check_name(name)) 149 return 0; 150 151 for (; (c = *name); name++) 152 /* check for legal char a-z A-Z 0-9 - _ . */ 153 { 154 if ((c >= 'A' && c <= 'Z') || 155 (c >= 'a' && c <= 'z') || 156 (c >= '0' && c <= '9') || 157 c == '-' || c == '_') 158 continue; 159 160 /* end of hostname part */ 161 if (c == '.') 162 return 1; 163 164 return 0; 165 } 166 167 return 1; 168 } 169 170 char *canonicalise(char *in, int *nomem) 171 { 172 char *ret = NULL; 173 #ifdef LOCALEDIR 174 int rc; 175 #endif 176 177 if (nomem) 178 *nomem = 0; 179 180 if (!check_name(in)) 181 return NULL; 182 183 #ifdef LOCALEDIR 184 if ((rc = idna_to_ascii_lz(in, &ret, 0)) != IDNA_SUCCESS) 185 { 186 if (ret) 187 free(ret); 188 189 if (nomem && (rc == IDNA_MALLOC_ERROR || rc == IDNA_DLOPEN_ERROR)) 190 { 191 my_syslog(LOG_ERR, _("failed to allocate memory")); 192 *nomem = 1; 193 } 194 195 return NULL; 196 } 197 #else 198 if ((ret = whine_malloc(strlen(in)+1))) 199 strcpy(ret, in); 200 else if (nomem) 201 *nomem = 1; 202 #endif 203 204 return ret; 205 } 206 207 unsigned char *do_rfc1035_name(unsigned char *p, char *sval) 208 { 209 int j; 210 211 while (sval && *sval) 212 { 213 unsigned char *cp = p++; 214 for (j = 0; *sval && (*sval != '.'); sval++, j++) 215 *p++ = *sval; 216 *cp = j; 217 if (*sval) 218 sval++; 219 } 220 return p; 221 } 222 223 /* for use during startup */ 224 void *safe_malloc(size_t size) 225 { 226 void *ret = malloc(size); 227 228 if (!ret) 229 die(_("could not get memory"), NULL, EC_NOMEM); 230 231 return ret; 232 } 233 234 void safe_pipe(int *fd, int read_noblock) 235 { 236 if (pipe(fd) == -1 || 237 !fix_fd(fd[1]) || 238 (read_noblock && !fix_fd(fd[0]))) 239 die(_("cannot create pipe: %s"), NULL, EC_MISC); 240 } 241 242 void *whine_malloc(size_t size) 243 { 244 void *ret = malloc(size); 245 246 if (!ret) 247 my_syslog(LOG_ERR, _("failed to allocate %d bytes"), (int) size); 248 249 return ret; 250 } 251 252 int sockaddr_isequal(union mysockaddr *s1, union mysockaddr *s2) 253 { 254 if (s1->sa.sa_family == s2->sa.sa_family) 255 { 256 if (s1->sa.sa_family == AF_INET && 257 s1->in.sin_port == s2->in.sin_port && 258 s1->in.sin_addr.s_addr == s2->in.sin_addr.s_addr) 259 return 1; 260 #ifdef HAVE_IPV6 261 if (s1->sa.sa_family == AF_INET6 && 262 s1->in6.sin6_port == s2->in6.sin6_port && 263 IN6_ARE_ADDR_EQUAL(&s1->in6.sin6_addr, &s2->in6.sin6_addr)) 264 return 1; 265 #endif 266 } 267 return 0; 268 } 269 270 int sa_len(union mysockaddr *addr) 271 { 272 #ifdef HAVE_SOCKADDR_SA_LEN 273 return addr->sa.sa_len; 274 #else 275 #ifdef HAVE_IPV6 276 if (addr->sa.sa_family == AF_INET6) 277 return sizeof(addr->in6); 278 else 279 #endif 280 return sizeof(addr->in); 281 #endif 282 } 283 284 /* don't use strcasecmp and friends here - they may be messed up by LOCALE */ 285 int hostname_isequal(char *a, char *b) 286 { 287 unsigned int c1, c2; 288 289 do { 290 c1 = (unsigned char) *a++; 291 c2 = (unsigned char) *b++; 292 293 if (c1 >= 'A' && c1 <= 'Z') 294 c1 += 'a' - 'A'; 295 if (c2 >= 'A' && c2 <= 'Z') 296 c2 += 'a' - 'A'; 297 298 if (c1 != c2) 299 return 0; 300 } while (c1); 301 302 return 1; 303 } 304 305 time_t dnsmasq_time(void) 306 { 307 #ifdef HAVE_BROKEN_RTC 308 struct tms dummy; 309 static long tps = 0; 310 311 if (tps == 0) 312 tps = sysconf(_SC_CLK_TCK); 313 314 return (time_t)(times(&dummy)/tps); 315 #else 316 return time(NULL); 317 #endif 318 } 319 320 int is_same_net(struct in_addr a, struct in_addr b, struct in_addr mask) 321 { 322 return (a.s_addr & mask.s_addr) == (b.s_addr & mask.s_addr); 323 } 324 325 /* returns port number from address */ 326 int prettyprint_addr(union mysockaddr *addr, char *buf) 327 { 328 int port = 0; 329 330 #ifdef HAVE_IPV6 331 if (addr->sa.sa_family == AF_INET) 332 { 333 inet_ntop(AF_INET, &addr->in.sin_addr, buf, ADDRSTRLEN); 334 port = ntohs(addr->in.sin_port); 335 } 336 else if (addr->sa.sa_family == AF_INET6) 337 { 338 inet_ntop(AF_INET6, &addr->in6.sin6_addr, buf, ADDRSTRLEN); 339 port = ntohs(addr->in6.sin6_port); 340 } 341 #else 342 strcpy(buf, inet_ntoa(addr->in.sin_addr)); 343 port = ntohs(addr->in.sin_port); 344 #endif 345 346 return port; 347 } 348 349 void prettyprint_time(char *buf, unsigned int t) 350 { 351 if (t == 0xffffffff) 352 sprintf(buf, _("infinite")); 353 else 354 { 355 unsigned int x, p = 0; 356 if ((x = t/86400)) 357 p += sprintf(&buf[p], "%dd", x); 358 if ((x = (t/3600)%24)) 359 p += sprintf(&buf[p], "%dh", x); 360 if ((x = (t/60)%60)) 361 p += sprintf(&buf[p], "%dm", x); 362 if ((x = t%60)) 363 p += sprintf(&buf[p], "%ds", x); 364 } 365 } 366 367 368 /* in may equal out, when maxlen may be -1 (No max len). */ 369 int parse_hex(char *in, unsigned char *out, int maxlen, 370 unsigned int *wildcard_mask, int *mac_type) 371 { 372 int mask = 0, i = 0; 373 char *r; 374 375 if (mac_type) 376 *mac_type = 0; 377 378 while (maxlen == -1 || i < maxlen) 379 { 380 for (r = in; *r != 0 && *r != ':' && *r != '-'; r++); 381 if (*r == 0) 382 maxlen = i; 383 384 if (r != in ) 385 { 386 if (*r == '-' && i == 0 && mac_type) 387 { 388 *r = 0; 389 *mac_type = strtol(in, NULL, 16); 390 mac_type = NULL; 391 } 392 else 393 { 394 *r = 0; 395 mask = mask << 1; 396 if (strcmp(in, "*") == 0) 397 mask |= 1; 398 else 399 out[i] = strtol(in, NULL, 16); 400 i++; 401 } 402 } 403 in = r+1; 404 } 405 406 if (wildcard_mask) 407 *wildcard_mask = mask; 408 409 return i; 410 } 411 412 /* return 0 for no match, or (no matched octets) + 1 */ 413 int memcmp_masked(unsigned char *a, unsigned char *b, int len, unsigned int mask) 414 { 415 int i, count; 416 for (count = 1, i = len - 1; i >= 0; i--, mask = mask >> 1) 417 if (!(mask & 1)) 418 { 419 if (a[i] == b[i]) 420 count++; 421 else 422 return 0; 423 } 424 return count; 425 } 426 427 /* _note_ may copy buffer */ 428 int expand_buf(struct iovec *iov, size_t size) 429 { 430 void *new; 431 432 if (size <= (size_t)iov->iov_len) 433 return 1; 434 435 if (!(new = whine_malloc(size))) 436 { 437 errno = ENOMEM; 438 return 0; 439 } 440 441 if (iov->iov_base) 442 { 443 memcpy(new, iov->iov_base, iov->iov_len); 444 free(iov->iov_base); 445 } 446 447 iov->iov_base = new; 448 iov->iov_len = size; 449 450 return 1; 451 } 452 453 char *print_mac(char *buff, unsigned char *mac, int len) 454 { 455 char *p = buff; 456 int i; 457 458 if (len == 0) 459 sprintf(p, "<null>"); 460 else 461 for (i = 0; i < len; i++) 462 p += sprintf(p, "%.2x%s", mac[i], (i == len - 1) ? "" : ":"); 463 464 return buff; 465 } 466 467 void bump_maxfd(int fd, int *max) 468 { 469 if (fd > *max) 470 *max = fd; 471 } 472 473 int retry_send(void) 474 { 475 struct timespec waiter; 476 if (errno == EAGAIN) 477 { 478 waiter.tv_sec = 0; 479 waiter.tv_nsec = 10000; 480 nanosleep(&waiter, NULL); 481 return 1; 482 } 483 484 if (errno == EINTR) 485 return 1; 486 487 return 0; 488 } 489 490 int read_write(int fd, unsigned char *packet, int size, int rw) 491 { 492 ssize_t n, done; 493 494 for (done = 0; done < size; done += n) 495 { 496 retry: 497 if (rw) 498 n = read(fd, &packet[done], (size_t)(size - done)); 499 else 500 n = write(fd, &packet[done], (size_t)(size - done)); 501 502 if (n == 0) 503 return 0; 504 else if (n == -1) 505 { 506 if (retry_send() || errno == ENOMEM || errno == ENOBUFS) 507 goto retry; 508 else 509 return 0; 510 } 511 } 512 return 1; 513 } 514 515
