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 #include <netdb.h> 24 25 #ifdef HAVE_BROKEN_RTC 26 #include <sys/times.h> 27 #endif 28 29 #ifdef LOCALEDIR 30 #include <idna.h> 31 #endif 32 33 #ifdef HAVE_ARC4RANDOM 34 void rand_init(void) 35 { 36 return; 37 } 38 39 unsigned short rand16(void) 40 { 41 return (unsigned short) (arc4random() >> 15); 42 } 43 44 #else 45 46 /* SURF random number generator */ 47 48 typedef unsigned int uint32; 49 50 static uint32 seed[32]; 51 static uint32 in[12]; 52 static uint32 out[8]; 53 54 void rand_init() 55 { 56 int fd = open(RANDFILE, O_RDONLY); 57 58 if (fd == -1 || 59 !read_write(fd, (unsigned char *)&seed, sizeof(seed), 1) || 60 !read_write(fd, (unsigned char *)&in, sizeof(in), 1)) 61 die(_("failed to seed the random number generator: %s"), NULL, EC_MISC); 62 63 close(fd); 64 } 65 66 #define ROTATE(x,b) (((x) << (b)) | ((x) >> (32 - (b)))) 67 #define MUSH(i,b) x = t[i] += (((x ^ seed[i]) + sum) ^ ROTATE(x,b)); 68 69 static void surf(void) 70 { 71 uint32 t[12]; uint32 x; uint32 sum = 0; 72 int r; int i; int loop; 73 74 for (i = 0;i < 12;++i) t[i] = in[i] ^ seed[12 + i]; 75 for (i = 0;i < 8;++i) out[i] = seed[24 + i]; 76 x = t[11]; 77 for (loop = 0;loop < 2;++loop) { 78 for (r = 0;r < 16;++r) { 79 sum += 0x9e3779b9; 80 MUSH(0,5) MUSH(1,7) MUSH(2,9) MUSH(3,13) 81 MUSH(4,5) MUSH(5,7) MUSH(6,9) MUSH(7,13) 82 MUSH(8,5) MUSH(9,7) MUSH(10,9) MUSH(11,13) 83 } 84 for (i = 0;i < 8;++i) out[i] ^= t[i + 4]; 85 } 86 } 87 88 unsigned short rand16(void) 89 { 90 static int outleft = 0; 91 92 if (!outleft) { 93 if (!++in[0]) if (!++in[1]) if (!++in[2]) ++in[3]; 94 surf(); 95 outleft = 8; 96 } 97 98 return (unsigned short) out[--outleft]; 99 } 100 101 #endif 102 103 static int check_name(char *in) 104 { 105 /* remove trailing . 106 also fail empty string and label > 63 chars */ 107 size_t dotgap = 0, l = strlen(in); 108 char c; 109 int nowhite = 0; 110 111 if (l == 0 || l > MAXDNAME) return 0; 112 113 if (in[l-1] == '.') 114 { 115 if (l == 1) return 0; 116 in[l-1] = 0; 117 } 118 119 for (; (c = *in); in++) 120 { 121 if (c == '.') 122 dotgap = 0; 123 else if (++dotgap > MAXLABEL) 124 return 0; 125 else if (isascii(c) && iscntrl(c)) 126 /* iscntrl only gives expected results for ascii */ 127 return 0; 128 #ifndef LOCALEDIR 129 else if (!isascii(c)) 130 return 0; 131 #endif 132 else if (c != ' ') 133 nowhite = 1; 134 } 135 136 if (!nowhite) 137 return 0; 138 139 return 1; 140 } 141 142 /* Hostnames have a more limited valid charset than domain names 143 so check for legal char a-z A-Z 0-9 - _ 144 Note that this may receive a FQDN, so only check the first label 145 for the tighter criteria. */ 146 int legal_hostname(char *name) 147 { 148 char c; 149 150 if (!check_name(name)) 151 return 0; 152 153 for (; (c = *name); name++) 154 /* check for legal char a-z A-Z 0-9 - _ . */ 155 { 156 if ((c >= 'A' && c <= 'Z') || 157 (c >= 'a' && c <= 'z') || 158 (c >= '0' && c <= '9') || 159 c == '-' || c == '_') 160 continue; 161 162 /* end of hostname part */ 163 if (c == '.') 164 return 1; 165 166 return 0; 167 } 168 169 return 1; 170 } 171 172 char *canonicalise(char *in, int *nomem) 173 { 174 char *ret = NULL; 175 #ifdef LOCALEDIR 176 int rc; 177 #endif 178 179 if (nomem) 180 *nomem = 0; 181 182 if (!check_name(in)) 183 return NULL; 184 185 #ifdef LOCALEDIR 186 if ((rc = idna_to_ascii_lz(in, &ret, 0)) != IDNA_SUCCESS) 187 { 188 if (ret) 189 free(ret); 190 191 if (nomem && (rc == IDNA_MALLOC_ERROR || rc == IDNA_DLOPEN_ERROR)) 192 { 193 my_syslog(LOG_ERR, _("failed to allocate memory")); 194 *nomem = 1; 195 } 196 197 return NULL; 198 } 199 #else 200 if ((ret = whine_malloc(strlen(in)+1))) 201 strcpy(ret, in); 202 else if (nomem) 203 *nomem = 1; 204 #endif 205 206 return ret; 207 } 208 209 unsigned char *do_rfc1035_name(unsigned char *p, char *sval) 210 { 211 int j; 212 213 while (sval && *sval) 214 { 215 unsigned char *cp = p++; 216 for (j = 0; *sval && (*sval != '.'); sval++, j++) 217 *p++ = *sval; 218 *cp = j; 219 if (*sval) 220 sval++; 221 } 222 return p; 223 } 224 225 /* for use during startup */ 226 void *safe_malloc(size_t size) 227 { 228 void *ret = malloc(size); 229 230 if (!ret) 231 die(_("could not get memory"), NULL, EC_NOMEM); 232 233 return ret; 234 } 235 236 void safe_pipe(int *fd, int read_noblock) 237 { 238 if (pipe(fd) == -1 || 239 !fix_fd(fd[1]) || 240 (read_noblock && !fix_fd(fd[0]))) 241 die(_("cannot create pipe: %s"), NULL, EC_MISC); 242 } 243 244 void *whine_malloc(size_t size) 245 { 246 void *ret = malloc(size); 247 248 if (!ret) 249 my_syslog(LOG_ERR, _("failed to allocate %d bytes"), (int) size); 250 251 return ret; 252 } 253 254 int sockaddr_isequal(union mysockaddr *s1, union mysockaddr *s2) 255 { 256 if (s1->sa.sa_family == s2->sa.sa_family) 257 { 258 if (s1->sa.sa_family == AF_INET && 259 s1->in.sin_port == s2->in.sin_port && 260 s1->in.sin_addr.s_addr == s2->in.sin_addr.s_addr) 261 return 1; 262 #ifdef HAVE_IPV6 263 if (s1->sa.sa_family == AF_INET6 && 264 s1->in6.sin6_port == s2->in6.sin6_port && 265 IN6_ARE_ADDR_EQUAL(&s1->in6.sin6_addr, &s2->in6.sin6_addr) && 266 (!IN6_IS_ADDR_LINKLOCAL(&s1->in6.sin6_addr) || 267 (s1->in6.sin6_scope_id == s2->in6.sin6_scope_id))) 268 return 1; 269 #endif 270 } 271 return 0; 272 } 273 274 int sa_len(union mysockaddr *addr) 275 { 276 #ifdef HAVE_SOCKADDR_SA_LEN 277 return addr->sa.sa_len; 278 #else 279 #ifdef HAVE_IPV6 280 if (addr->sa.sa_family == AF_INET6) 281 return sizeof(addr->in6); 282 else 283 #endif 284 return sizeof(addr->in); 285 #endif 286 } 287 288 /* don't use strcasecmp and friends here - they may be messed up by LOCALE */ 289 int hostname_isequal(char *a, char *b) 290 { 291 unsigned int c1, c2; 292 293 do { 294 c1 = (unsigned char) *a++; 295 c2 = (unsigned char) *b++; 296 297 if (c1 >= 'A' && c1 <= 'Z') 298 c1 += 'a' - 'A'; 299 if (c2 >= 'A' && c2 <= 'Z') 300 c2 += 'a' - 'A'; 301 302 if (c1 != c2) 303 return 0; 304 } while (c1); 305 306 return 1; 307 } 308 309 time_t dnsmasq_time(void) 310 { 311 #ifdef HAVE_BROKEN_RTC 312 struct tms dummy; 313 static long tps = 0; 314 315 if (tps == 0) 316 tps = sysconf(_SC_CLK_TCK); 317 318 return (time_t)(times(&dummy)/tps); 319 #else 320 return time(NULL); 321 #endif 322 } 323 324 int is_same_net(struct in_addr a, struct in_addr b, struct in_addr mask) 325 { 326 return (a.s_addr & mask.s_addr) == (b.s_addr & mask.s_addr); 327 } 328 329 int parse_addr(int family, const char *addrstr, union mysockaddr *addr) 330 { 331 struct addrinfo *res, hints = { 332 .ai_flags = AI_NUMERICHOST, 333 .ai_family = family, 334 .ai_socktype = SOCK_DGRAM, 335 }; 336 337 int ret = getaddrinfo(addrstr, NULL, &hints, &res); 338 if (ret) { 339 return ret; 340 } 341 342 switch (res->ai_family) { 343 case AF_INET: 344 addr->in = *((struct sockaddr_in *) res->ai_addr); 345 break; 346 #ifdef HAVE_IPV6 347 case AF_INET6: 348 addr->in6 = *((struct sockaddr_in6 *) res->ai_addr); 349 break; 350 #endif 351 default: 352 errno = EAFNOSUPPORT; 353 ret = -1; 354 break; 355 } 356 freeaddrinfo(res); 357 return ret; 358 } 359 360 /* returns port number from address */ 361 int prettyprint_addr(const union mysockaddr *addr, char *buf) 362 { 363 int port = 0; 364 365 #ifdef HAVE_IPV6 366 char portstr[strlen("65535")]; 367 getnameinfo((const struct sockaddr *) addr, sizeof(*addr), buf, ADDRSTRLEN, 368 portstr, sizeof(portstr), NI_NUMERICHOST | NI_NUMERICSERV); 369 port = atoi(portstr); 370 #else 371 strcpy(buf, inet_ntoa(addr->in.sin_addr)); 372 port = ntohs(addr->in.sin_port); 373 #endif 374 375 return port; 376 } 377 378 void prettyprint_time(char *buf, unsigned int t) 379 { 380 if (t == 0xffffffff) 381 sprintf(buf, _("infinite")); 382 else 383 { 384 unsigned int x, p = 0; 385 if ((x = t/86400)) 386 p += sprintf(&buf[p], "%dd", x); 387 if ((x = (t/3600)%24)) 388 p += sprintf(&buf[p], "%dh", x); 389 if ((x = (t/60)%60)) 390 p += sprintf(&buf[p], "%dm", x); 391 if ((x = t%60)) 392 p += sprintf(&buf[p], "%ds", x); 393 } 394 } 395 396 397 /* in may equal out, when maxlen may be -1 (No max len). */ 398 int parse_hex(char *in, unsigned char *out, int maxlen, 399 unsigned int *wildcard_mask, int *mac_type) 400 { 401 int mask = 0, i = 0; 402 char *r; 403 404 if (mac_type) 405 *mac_type = 0; 406 407 while (maxlen == -1 || i < maxlen) 408 { 409 for (r = in; *r != 0 && *r != ':' && *r != '-'; r++); 410 if (*r == 0) 411 maxlen = i; 412 413 if (r != in ) 414 { 415 if (*r == '-' && i == 0 && mac_type) 416 { 417 *r = 0; 418 *mac_type = strtol(in, NULL, 16); 419 mac_type = NULL; 420 } 421 else 422 { 423 *r = 0; 424 mask = mask << 1; 425 if (strcmp(in, "*") == 0) 426 mask |= 1; 427 else 428 out[i] = strtol(in, NULL, 16); 429 i++; 430 } 431 } 432 in = r+1; 433 } 434 435 if (wildcard_mask) 436 *wildcard_mask = mask; 437 438 return i; 439 } 440 441 /* return 0 for no match, or (no matched octets) + 1 */ 442 int memcmp_masked(unsigned char *a, unsigned char *b, int len, unsigned int mask) 443 { 444 int i, count; 445 for (count = 1, i = len - 1; i >= 0; i--, mask = mask >> 1) 446 if (!(mask & 1)) 447 { 448 if (a[i] == b[i]) 449 count++; 450 else 451 return 0; 452 } 453 return count; 454 } 455 456 /* _note_ may copy buffer */ 457 int expand_buf(struct iovec *iov, size_t size) 458 { 459 void *new; 460 461 if (size <= (size_t)iov->iov_len) 462 return 1; 463 464 if (!(new = whine_malloc(size))) 465 { 466 errno = ENOMEM; 467 return 0; 468 } 469 470 if (iov->iov_base) 471 { 472 memcpy(new, iov->iov_base, iov->iov_len); 473 free(iov->iov_base); 474 } 475 476 iov->iov_base = new; 477 iov->iov_len = size; 478 479 return 1; 480 } 481 482 char *print_mac(char *buff, unsigned char *mac, int len) 483 { 484 char *p = buff; 485 int i; 486 487 if (len == 0) 488 sprintf(p, "<null>"); 489 else 490 for (i = 0; i < len; i++) 491 p += sprintf(p, "%.2x%s", mac[i], (i == len - 1) ? "" : ":"); 492 493 return buff; 494 } 495 496 void bump_maxfd(int fd, int *max) 497 { 498 if (fd > *max) 499 *max = fd; 500 } 501 502 int retry_send(void) 503 { 504 struct timespec waiter; 505 if (errno == EAGAIN) 506 { 507 waiter.tv_sec = 0; 508 waiter.tv_nsec = 10000; 509 nanosleep(&waiter, NULL); 510 return 1; 511 } 512 513 if (errno == EINTR) 514 return 1; 515 516 return 0; 517 } 518 519 int read_write(int fd, unsigned char *packet, int size, int rw) 520 { 521 ssize_t n, done; 522 523 for (done = 0; done < size; done += n) 524 { 525 retry: 526 if (rw) 527 n = read(fd, &packet[done], (size_t)(size - done)); 528 else 529 n = write(fd, &packet[done], (size_t)(size - done)); 530 531 if (n == 0) 532 return 0; 533 else if (n == -1) 534 { 535 if (retry_send() || errno == ENOMEM || errno == ENOBUFS) 536 goto retry; 537 else 538 return 0; 539 } 540 } 541 return 1; 542 } 543 544
