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
rand_init(void)34 void rand_init(void)
35 {
36 return;
37 }
38
rand16(void)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
rand_init()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
surf(void)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
rand16(void)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
check_name(char * in)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. */
legal_hostname(char * name)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
canonicalise(char * in,int * nomem)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
do_rfc1035_name(unsigned char * p,char * sval)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 */
safe_malloc(size_t size)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
safe_pipe(int * fd,int read_noblock)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
whine_malloc(size_t size)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
sockaddr_isequal(union mysockaddr * s1,union mysockaddr * s2)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
sa_len(union mysockaddr * addr)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 */
hostname_isequal(char * a,char * b)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
dnsmasq_time(void)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
is_same_net(struct in_addr a,struct in_addr b,struct in_addr mask)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
parse_addr(int family,const char * addrstr,union mysockaddr * addr)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 */
prettyprint_addr(const union mysockaddr * addr,char * buf)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
prettyprint_time(char * buf,unsigned int t)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). */
parse_hex(char * in,unsigned char * out,int maxlen,unsigned int * wildcard_mask,int * mac_type)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 */
memcmp_masked(unsigned char * a,unsigned char * b,int len,unsigned int mask)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 */
expand_buf(struct iovec * iov,size_t size)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
print_mac(char * buff,unsigned char * mac,int len)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
bump_maxfd(int fd,int * max)496 void bump_maxfd(int fd, int *max)
497 {
498 if (fd > *max)
499 *max = fd;
500 }
501
retry_send(void)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
read_write(int fd,unsigned char * packet,int size,int rw)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