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 #include "dnsmasq.h" 21 22 #include <netdb.h> 23 24 #ifdef HAVE_BROKEN_RTC 25 #include <sys/times.h> 26 #endif 27 28 #ifdef LOCALEDIR 29 #include <idna.h> 30 #endif 31 32 #ifdef HAVE_ARC4RANDOM 33 void rand_init(void) { 34 return; 35 } 36 37 unsigned short rand16(void) { 38 return (unsigned short) (arc4random() >> 15); 39 } 40 41 #else 42 43 /* SURF random number generator */ 44 45 typedef unsigned int uint32; 46 47 static uint32 seed[32]; 48 static uint32 in[12]; 49 static uint32 out[8]; 50 51 void rand_init() { 52 int fd = open(RANDFILE, O_RDONLY); 53 54 if (fd == -1 || !read_write(fd, (unsigned char*) &seed, sizeof(seed), 1) || 55 !read_write(fd, (unsigned char*) &in, sizeof(in), 1)) 56 die(_("failed to seed the random number generator: %s"), NULL, EC_MISC); 57 58 close(fd); 59 } 60 61 #define ROTATE(x, b) (((x) << (b)) | ((x) >> (32 - (b)))) 62 #define MUSH(i, b) x = t[i] += (((x ^ seed[i]) + sum) ^ ROTATE(x, b)); 63 64 static void surf(void) { 65 uint32 t[12]; 66 uint32 x; 67 uint32 sum = 0; 68 int r; 69 int i; 70 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) 79 MUSH(1, 7) MUSH(2, 9) MUSH(3, 13) 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 static int outleft = 0; 88 89 if (!outleft) { 90 if (!++in[0]) 91 if (!++in[1]) 92 if (!++in[2]) ++in[3]; 93 surf(); 94 outleft = 8; 95 } 96 97 return (unsigned short) out[--outleft]; 98 } 99 100 #endif 101 102 static int check_name(char* in) { 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 if (l == 1) return 0; 113 in[l - 1] = 0; 114 } 115 116 for (; (c = *in); in++) { 117 if (c == '.') 118 dotgap = 0; 119 else if (++dotgap > MAXLABEL) 120 return 0; 121 else if (isascii(c) && iscntrl(c)) 122 /* iscntrl only gives expected results for ascii */ 123 return 0; 124 #ifndef LOCALEDIR 125 else if (!isascii(c)) 126 return 0; 127 #endif 128 else if (c != ' ') 129 nowhite = 1; 130 } 131 132 if (!nowhite) return 0; 133 134 return 1; 135 } 136 137 /* Hostnames have a more limited valid charset than domain names 138 so check for legal char a-z A-Z 0-9 - _ 139 Note that this may receive a FQDN, so only check the first label 140 for the tighter criteria. */ 141 int legal_hostname(char* name) { 142 char c; 143 144 if (!check_name(name)) return 0; 145 146 for (; (c = *name); name++) 147 /* check for legal char a-z A-Z 0-9 - _ . */ 148 { 149 if ((c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z') || (c >= '0' && c <= '9') || 150 c == '-' || c == '_') 151 continue; 152 153 /* end of hostname part */ 154 if (c == '.') return 1; 155 156 return 0; 157 } 158 159 return 1; 160 } 161 162 char* canonicalise(char* in, int* nomem) { 163 char* ret = NULL; 164 #ifdef LOCALEDIR 165 int rc; 166 #endif 167 168 if (nomem) *nomem = 0; 169 170 if (!check_name(in)) return NULL; 171 172 #ifdef LOCALEDIR 173 if ((rc = idna_to_ascii_lz(in, &ret, 0)) != IDNA_SUCCESS) { 174 if (ret) free(ret); 175 176 if (nomem && (rc == IDNA_MALLOC_ERROR || rc == IDNA_DLOPEN_ERROR)) { 177 my_syslog(LOG_ERR, _("failed to allocate memory")); 178 *nomem = 1; 179 } 180 181 return NULL; 182 } 183 #else 184 if ((ret = whine_malloc(strlen(in) + 1))) 185 strcpy(ret, in); 186 else if (nomem) 187 *nomem = 1; 188 #endif 189 190 return ret; 191 } 192 193 unsigned char* do_rfc1035_name(unsigned char* p, char* sval) { 194 int j; 195 196 while (sval && *sval) { 197 unsigned char* cp = p++; 198 for (j = 0; *sval && (*sval != '.'); sval++, j++) *p++ = *sval; 199 *cp = j; 200 if (*sval) sval++; 201 } 202 return p; 203 } 204 205 /* for use during startup */ 206 void* safe_malloc(size_t size) { 207 void* ret = malloc(size); 208 209 if (!ret) die(_("could not get memory"), NULL, EC_NOMEM); 210 211 return ret; 212 } 213 214 void safe_pipe(int* fd, int read_noblock) { 215 if (pipe(fd) == -1 || !fix_fd(fd[1]) || (read_noblock && !fix_fd(fd[0]))) 216 die(_("cannot create pipe: %s"), NULL, EC_MISC); 217 } 218 219 void* whine_malloc(size_t size) { 220 void* ret = malloc(size); 221 222 if (!ret) my_syslog(LOG_ERR, _("failed to allocate %d bytes"), (int) size); 223 224 return ret; 225 } 226 227 int sockaddr_isequal(union mysockaddr* s1, union mysockaddr* s2) { 228 if (s1->sa.sa_family == s2->sa.sa_family) { 229 if (s1->sa.sa_family == AF_INET && s1->in.sin_port == s2->in.sin_port && 230 s1->in.sin_addr.s_addr == s2->in.sin_addr.s_addr) 231 return 1; 232 #ifdef HAVE_IPV6 233 if (s1->sa.sa_family == AF_INET6 && s1->in6.sin6_port == s2->in6.sin6_port && 234 IN6_ARE_ADDR_EQUAL(&s1->in6.sin6_addr, &s2->in6.sin6_addr) && 235 (!IN6_IS_ADDR_LINKLOCAL(&s1->in6.sin6_addr) || 236 (s1->in6.sin6_scope_id == s2->in6.sin6_scope_id))) 237 return 1; 238 #endif 239 } 240 return 0; 241 } 242 243 int sa_len(union mysockaddr* addr) { 244 if (addr->sa.sa_family == AF_INET6) 245 return sizeof(addr->in6); 246 else 247 return sizeof(addr->in); 248 } 249 250 /* don't use strcasecmp and friends here - they may be messed up by LOCALE */ 251 int hostname_isequal(char* a, char* b) { 252 unsigned int c1, c2; 253 254 do { 255 c1 = (unsigned char) *a++; 256 c2 = (unsigned char) *b++; 257 258 if (c1 >= 'A' && c1 <= 'Z') c1 += 'a' - 'A'; 259 if (c2 >= 'A' && c2 <= 'Z') c2 += 'a' - 'A'; 260 261 if (c1 != c2) return 0; 262 } while (c1); 263 264 return 1; 265 } 266 267 time_t dnsmasq_time(void) { 268 #ifdef HAVE_BROKEN_RTC 269 struct tms dummy; 270 static long tps = 0; 271 272 if (tps == 0) tps = sysconf(_SC_CLK_TCK); 273 274 return (time_t)(times(&dummy) / tps); 275 #else 276 return time(NULL); 277 #endif 278 } 279 280 int is_same_net(struct in_addr a, struct in_addr b, struct in_addr mask) { 281 return (a.s_addr & mask.s_addr) == (b.s_addr & mask.s_addr); 282 } 283 284 int parse_addr(int family, const char* addrstr, union mysockaddr* addr) { 285 struct addrinfo *res, hints = { 286 .ai_flags = AI_NUMERICHOST, 287 .ai_family = family, 288 .ai_socktype = SOCK_DGRAM, 289 }; 290 291 int ret = getaddrinfo(addrstr, NULL, &hints, &res); 292 if (ret) { 293 return ret; 294 } 295 296 switch (res->ai_family) { 297 case AF_INET: 298 addr->in = *((struct sockaddr_in*) res->ai_addr); 299 break; 300 #ifdef HAVE_IPV6 301 case AF_INET6: 302 addr->in6 = *((struct sockaddr_in6*) res->ai_addr); 303 break; 304 #endif 305 default: 306 errno = EAFNOSUPPORT; 307 ret = -1; 308 break; 309 } 310 freeaddrinfo(res); 311 return ret; 312 } 313 314 /* returns port number from address */ 315 int prettyprint_addr(const union mysockaddr* addr, char* buf) { 316 int port = 0; 317 318 #ifdef HAVE_IPV6 319 char portstr[strlen("65535")]; 320 getnameinfo((const struct sockaddr*) addr, sizeof(*addr), buf, ADDRSTRLEN, portstr, 321 sizeof(portstr), NI_NUMERICHOST | NI_NUMERICSERV); 322 port = atoi(portstr); 323 #else 324 strcpy(buf, inet_ntoa(addr->in.sin_addr)); 325 port = ntohs(addr->in.sin_port); 326 #endif 327 328 return port; 329 } 330 331 void prettyprint_time(char* buf, unsigned int t) { 332 if (t == 0xffffffff) 333 sprintf(buf, _("infinite")); 334 else { 335 unsigned int x, p = 0; 336 if ((x = t / 86400)) p += sprintf(&buf[p], "%dd", x); 337 if ((x = (t / 3600) % 24)) p += sprintf(&buf[p], "%dh", x); 338 if ((x = (t / 60) % 60)) p += sprintf(&buf[p], "%dm", x); 339 if ((x = t % 60)) p += sprintf(&buf[p], "%ds", x); 340 } 341 } 342 343 /* in may equal out, when maxlen may be -1 (No max len). */ 344 int parse_hex(char* in, unsigned char* out, int maxlen, unsigned int* wildcard_mask, int* mac_type) { 345 int mask = 0, i = 0; 346 char* r; 347 348 if (mac_type) *mac_type = 0; 349 350 while (maxlen == -1 || i < maxlen) { 351 for (r = in; *r != 0 && *r != ':' && *r != '-'; r++) 352 ; 353 if (*r == 0) maxlen = i; 354 355 if (r != in) { 356 if (*r == '-' && i == 0 && mac_type) { 357 *r = 0; 358 *mac_type = strtol(in, NULL, 16); 359 mac_type = NULL; 360 } else { 361 *r = 0; 362 mask = mask << 1; 363 if (strcmp(in, "*") == 0) 364 mask |= 1; 365 else 366 out[i] = strtol(in, NULL, 16); 367 i++; 368 } 369 } 370 in = r + 1; 371 } 372 373 if (wildcard_mask) *wildcard_mask = mask; 374 375 return i; 376 } 377 378 /* return 0 for no match, or (no matched octets) + 1 */ 379 int memcmp_masked(unsigned char* a, unsigned char* b, int len, unsigned int mask) { 380 int i, count; 381 for (count = 1, i = len - 1; i >= 0; i--, mask = mask >> 1) 382 if (!(mask & 1)) { 383 if (a[i] == b[i]) 384 count++; 385 else 386 return 0; 387 } 388 return count; 389 } 390 391 /* _note_ may copy buffer */ 392 int expand_buf(struct iovec* iov, size_t size) { 393 void* new; 394 395 if (size <= (size_t) iov->iov_len) return 1; 396 397 if (!(new = whine_malloc(size))) { 398 errno = ENOMEM; 399 return 0; 400 } 401 402 if (iov->iov_base) { 403 memcpy(new, iov->iov_base, iov->iov_len); 404 free(iov->iov_base); 405 } 406 407 iov->iov_base = new; 408 iov->iov_len = size; 409 410 return 1; 411 } 412 413 char* print_mac(char* buff, unsigned char* mac, int len) { 414 char* p = buff; 415 int i; 416 417 if (len == 0) 418 sprintf(p, "<null>"); 419 else 420 for (i = 0; i < len; i++) p += sprintf(p, "%.2x%s", mac[i], (i == len - 1) ? "" : ":"); 421 422 return buff; 423 } 424 425 void bump_maxfd(int fd, int* max) { 426 if (fd > *max) *max = fd; 427 } 428 429 int retry_send(void) { 430 struct timespec waiter; 431 if (errno == EAGAIN) { 432 waiter.tv_sec = 0; 433 waiter.tv_nsec = 10000; 434 nanosleep(&waiter, NULL); 435 return 1; 436 } 437 438 if (errno == EINTR) return 1; 439 440 return 0; 441 } 442 443 int read_write(int fd, unsigned char* packet, int size, int rw) { 444 ssize_t n, done; 445 446 for (done = 0; done < size; done += n) { 447 retry: 448 if (rw) 449 n = read(fd, &packet[done], (size_t)(size - done)); 450 else 451 n = write(fd, &packet[done], (size_t)(size - done)); 452 453 if (n == 0) 454 return 0; 455 else if (n == -1) { 456 if (retry_send() || errno == ENOMEM || errno == ENOBUFS) 457 goto retry; 458 else 459 return 0; 460 } 461 } 462 return 1; 463 } 464
