mirror of
https://github.com/pi-hole/dnsmasq.git
synced 2025-12-19 10:18:25 +00:00
660 lines
13 KiB
C
660 lines
13 KiB
C
/* dnsmasq is Copyright (c) 2000-2014 Simon Kelley
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; version 2 dated June, 1991, or
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(at your option) version 3 dated 29 June, 2007.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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/* The SURF random number generator was taken from djbdns-1.05, by
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Daniel J Bernstein, which is public domain. */
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#include "dnsmasq.h"
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#ifdef HAVE_BROKEN_RTC
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#include <sys/times.h>
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#endif
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#if defined(LOCALEDIR) || defined(HAVE_IDN)
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#include <idna.h>
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#endif
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/* SURF random number generator */
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static u32 seed[32];
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static u32 in[12];
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static u32 out[8];
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static int outleft = 0;
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void rand_init()
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{
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int fd = open(RANDFILE, O_RDONLY);
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if (fd == -1 ||
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!read_write(fd, (unsigned char *)&seed, sizeof(seed), 1) ||
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!read_write(fd, (unsigned char *)&in, sizeof(in), 1))
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die(_("failed to seed the random number generator: %s"), NULL, EC_MISC);
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close(fd);
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}
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#define ROTATE(x,b) (((x) << (b)) | ((x) >> (32 - (b))))
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#define MUSH(i,b) x = t[i] += (((x ^ seed[i]) + sum) ^ ROTATE(x,b));
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static void surf(void)
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{
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u32 t[12]; u32 x; u32 sum = 0;
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int r; int i; int loop;
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for (i = 0;i < 12;++i) t[i] = in[i] ^ seed[12 + i];
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for (i = 0;i < 8;++i) out[i] = seed[24 + i];
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x = t[11];
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for (loop = 0;loop < 2;++loop) {
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for (r = 0;r < 16;++r) {
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sum += 0x9e3779b9;
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MUSH(0,5) MUSH(1,7) MUSH(2,9) MUSH(3,13)
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MUSH(4,5) MUSH(5,7) MUSH(6,9) MUSH(7,13)
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MUSH(8,5) MUSH(9,7) MUSH(10,9) MUSH(11,13)
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}
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for (i = 0;i < 8;++i) out[i] ^= t[i + 4];
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}
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}
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unsigned short rand16(void)
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{
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if (!outleft)
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{
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if (!++in[0]) if (!++in[1]) if (!++in[2]) ++in[3];
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surf();
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outleft = 8;
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}
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return (unsigned short) out[--outleft];
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}
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u32 rand32(void)
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{
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if (!outleft)
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{
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if (!++in[0]) if (!++in[1]) if (!++in[2]) ++in[3];
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surf();
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outleft = 8;
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}
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return out[--outleft];
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}
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u64 rand64(void)
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{
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static int outleft = 0;
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if (outleft < 2)
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{
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if (!++in[0]) if (!++in[1]) if (!++in[2]) ++in[3];
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surf();
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outleft = 8;
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}
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outleft -= 2;
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return (u64)out[outleft+1] + (((u64)out[outleft]) << 32);
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}
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static int check_name(char *in)
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{
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/* remove trailing .
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also fail empty string and label > 63 chars */
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size_t dotgap = 0, l = strlen(in);
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char c;
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int nowhite = 0;
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if (l == 0 || l > MAXDNAME) return 0;
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if (in[l-1] == '.')
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{
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in[l-1] = 0;
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nowhite = 1;
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}
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for (; (c = *in); in++)
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{
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if (c == '.')
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dotgap = 0;
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else if (++dotgap > MAXLABEL)
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return 0;
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else if (isascii((unsigned char)c) && iscntrl((unsigned char)c))
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/* iscntrl only gives expected results for ascii */
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return 0;
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#if !defined(LOCALEDIR) && !defined(HAVE_IDN)
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else if (!isascii((unsigned char)c))
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return 0;
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#endif
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else if (c != ' ')
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nowhite = 1;
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}
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if (!nowhite)
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return 0;
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return 1;
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}
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/* Hostnames have a more limited valid charset than domain names
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so check for legal char a-z A-Z 0-9 - _
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Note that this may receive a FQDN, so only check the first label
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for the tighter criteria. */
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int legal_hostname(char *name)
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{
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char c;
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int first;
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if (!check_name(name))
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return 0;
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for (first = 1; (c = *name); name++, first = 0)
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/* check for legal char a-z A-Z 0-9 - _ . */
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{
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if ((c >= 'A' && c <= 'Z') ||
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(c >= 'a' && c <= 'z') ||
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(c >= '0' && c <= '9'))
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continue;
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if (!first && (c == '-' || c == '_'))
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continue;
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/* end of hostname part */
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if (c == '.')
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return 1;
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return 0;
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}
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return 1;
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}
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char *canonicalise(char *in, int *nomem)
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{
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char *ret = NULL;
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#if defined(LOCALEDIR) || defined(HAVE_IDN)
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int rc;
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#endif
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if (nomem)
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*nomem = 0;
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if (!check_name(in))
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return NULL;
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#if defined(LOCALEDIR) || defined(HAVE_IDN)
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if ((rc = idna_to_ascii_lz(in, &ret, 0)) != IDNA_SUCCESS)
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{
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if (ret)
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free(ret);
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if (nomem && (rc == IDNA_MALLOC_ERROR || rc == IDNA_DLOPEN_ERROR))
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{
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my_syslog(LOG_ERR, _("failed to allocate memory"));
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*nomem = 1;
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}
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return NULL;
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}
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#else
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if ((ret = whine_malloc(strlen(in)+1)))
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strcpy(ret, in);
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else if (nomem)
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*nomem = 1;
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#endif
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return ret;
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}
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unsigned char *do_rfc1035_name(unsigned char *p, char *sval)
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{
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int j;
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while (sval && *sval)
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{
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unsigned char *cp = p++;
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for (j = 0; *sval && (*sval != '.'); sval++, j++)
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*p++ = *sval;
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*cp = j;
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if (*sval)
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sval++;
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}
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return p;
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}
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/* for use during startup */
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void *safe_malloc(size_t size)
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{
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void *ret = malloc(size);
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if (!ret)
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die(_("could not get memory"), NULL, EC_NOMEM);
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return ret;
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}
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void safe_pipe(int *fd, int read_noblock)
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{
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if (pipe(fd) == -1 ||
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!fix_fd(fd[1]) ||
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(read_noblock && !fix_fd(fd[0])))
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die(_("cannot create pipe: %s"), NULL, EC_MISC);
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}
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void *whine_malloc(size_t size)
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{
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void *ret = malloc(size);
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if (!ret)
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my_syslog(LOG_ERR, _("failed to allocate %d bytes"), (int) size);
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return ret;
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}
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int sockaddr_isequal(union mysockaddr *s1, union mysockaddr *s2)
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{
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if (s1->sa.sa_family == s2->sa.sa_family)
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{
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if (s1->sa.sa_family == AF_INET &&
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s1->in.sin_port == s2->in.sin_port &&
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s1->in.sin_addr.s_addr == s2->in.sin_addr.s_addr)
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return 1;
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#ifdef HAVE_IPV6
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if (s1->sa.sa_family == AF_INET6 &&
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s1->in6.sin6_port == s2->in6.sin6_port &&
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s1->in6.sin6_scope_id == s2->in6.sin6_scope_id &&
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IN6_ARE_ADDR_EQUAL(&s1->in6.sin6_addr, &s2->in6.sin6_addr))
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return 1;
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#endif
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}
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return 0;
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}
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int sa_len(union mysockaddr *addr)
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{
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#ifdef HAVE_SOCKADDR_SA_LEN
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return addr->sa.sa_len;
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#else
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#ifdef HAVE_IPV6
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if (addr->sa.sa_family == AF_INET6)
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return sizeof(addr->in6);
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else
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#endif
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return sizeof(addr->in);
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#endif
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}
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/* don't use strcasecmp and friends here - they may be messed up by LOCALE */
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int hostname_isequal(const char *a, const char *b)
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{
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unsigned int c1, c2;
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do {
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c1 = (unsigned char) *a++;
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c2 = (unsigned char) *b++;
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if (c1 >= 'A' && c1 <= 'Z')
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c1 += 'a' - 'A';
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if (c2 >= 'A' && c2 <= 'Z')
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c2 += 'a' - 'A';
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if (c1 != c2)
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return 0;
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} while (c1);
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return 1;
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}
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time_t dnsmasq_time(void)
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{
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#ifdef HAVE_BROKEN_RTC
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struct tms dummy;
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static long tps = 0;
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if (tps == 0)
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tps = sysconf(_SC_CLK_TCK);
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return (time_t)(times(&dummy)/tps);
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#else
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return time(NULL);
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#endif
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}
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int netmask_length(struct in_addr mask)
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{
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int zero_count = 0;
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while (0x0 == (mask.s_addr & 0x1) && zero_count < 32)
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{
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mask.s_addr >>= 1;
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zero_count++;
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}
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return 32 - zero_count;
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}
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int is_same_net(struct in_addr a, struct in_addr b, struct in_addr mask)
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{
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return (a.s_addr & mask.s_addr) == (b.s_addr & mask.s_addr);
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}
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#ifdef HAVE_IPV6
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int is_same_net6(struct in6_addr *a, struct in6_addr *b, int prefixlen)
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{
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int pfbytes = prefixlen >> 3;
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int pfbits = prefixlen & 7;
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if (memcmp(&a->s6_addr, &b->s6_addr, pfbytes) != 0)
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return 0;
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if (pfbits == 0 ||
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(a->s6_addr[pfbytes] >> (8 - pfbits) == b->s6_addr[pfbytes] >> (8 - pfbits)))
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return 1;
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return 0;
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}
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/* return least signigicant 64 bits if IPv6 address */
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u64 addr6part(struct in6_addr *addr)
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{
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int i;
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u64 ret = 0;
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for (i = 8; i < 16; i++)
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ret = (ret << 8) + addr->s6_addr[i];
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return ret;
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}
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void setaddr6part(struct in6_addr *addr, u64 host)
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{
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int i;
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for (i = 15; i >= 8; i--)
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{
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addr->s6_addr[i] = host;
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host = host >> 8;
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}
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}
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#endif
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/* returns port number from address */
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int prettyprint_addr(union mysockaddr *addr, char *buf)
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{
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int port = 0;
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#ifdef HAVE_IPV6
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if (addr->sa.sa_family == AF_INET)
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{
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inet_ntop(AF_INET, &addr->in.sin_addr, buf, ADDRSTRLEN);
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port = ntohs(addr->in.sin_port);
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}
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else if (addr->sa.sa_family == AF_INET6)
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{
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char name[IF_NAMESIZE];
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inet_ntop(AF_INET6, &addr->in6.sin6_addr, buf, ADDRSTRLEN);
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if (addr->in6.sin6_scope_id != 0 &&
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if_indextoname(addr->in6.sin6_scope_id, name) &&
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strlen(buf) + strlen(name) + 2 <= ADDRSTRLEN)
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{
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strcat(buf, "%");
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strcat(buf, name);
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}
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port = ntohs(addr->in6.sin6_port);
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}
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#else
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strcpy(buf, inet_ntoa(addr->in.sin_addr));
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port = ntohs(addr->in.sin_port);
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#endif
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return port;
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}
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void prettyprint_time(char *buf, unsigned int t)
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{
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if (t == 0xffffffff)
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sprintf(buf, _("infinite"));
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else
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{
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unsigned int x, p = 0;
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if ((x = t/86400))
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p += sprintf(&buf[p], "%dd", x);
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if ((x = (t/3600)%24))
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p += sprintf(&buf[p], "%dh", x);
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if ((x = (t/60)%60))
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p += sprintf(&buf[p], "%dm", x);
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if ((x = t%60))
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p += sprintf(&buf[p], "%ds", x);
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}
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}
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/* in may equal out, when maxlen may be -1 (No max len).
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Return -1 for extraneous no-hex chars found. */
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int parse_hex(char *in, unsigned char *out, int maxlen,
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unsigned int *wildcard_mask, int *mac_type)
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{
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int mask = 0, i = 0;
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char *r;
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if (mac_type)
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*mac_type = 0;
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while (maxlen == -1 || i < maxlen)
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{
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for (r = in; *r != 0 && *r != ':' && *r != '-' && *r != ' '; r++)
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if (*r != '*' && !isxdigit((unsigned char)*r))
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return -1;
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if (*r == 0)
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maxlen = i;
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if (r != in )
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{
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if (*r == '-' && i == 0 && mac_type)
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{
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*r = 0;
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*mac_type = strtol(in, NULL, 16);
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mac_type = NULL;
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}
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else
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{
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*r = 0;
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if (strcmp(in, "*") == 0)
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{
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mask = (mask << 1) | 1;
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i++;
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}
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else
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{
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int j, bytes = (1 + (r - in))/2;
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for (j = 0; j < bytes; j++)
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{
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char sav = sav;
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if (j < bytes - 1)
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{
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sav = in[(j+1)*2];
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in[(j+1)*2] = 0;
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}
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out[i] = strtol(&in[j*2], NULL, 16);
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mask = mask << 1;
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i++;
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if (j < bytes - 1)
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in[(j+1)*2] = sav;
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}
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}
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}
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}
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in = r+1;
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}
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if (wildcard_mask)
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*wildcard_mask = mask;
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return i;
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}
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/* return 0 for no match, or (no matched octets) + 1 */
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int memcmp_masked(unsigned char *a, unsigned char *b, int len, unsigned int mask)
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{
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int i, count;
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for (count = 1, i = len - 1; i >= 0; i--, mask = mask >> 1)
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if (!(mask & 1))
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{
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if (a[i] == b[i])
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count++;
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else
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return 0;
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}
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return count;
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}
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/* _note_ may copy buffer */
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int expand_buf(struct iovec *iov, size_t size)
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{
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void *new;
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if (size <= (size_t)iov->iov_len)
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return 1;
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if (!(new = whine_malloc(size)))
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{
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errno = ENOMEM;
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return 0;
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}
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if (iov->iov_base)
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{
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memcpy(new, iov->iov_base, iov->iov_len);
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free(iov->iov_base);
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}
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iov->iov_base = new;
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iov->iov_len = size;
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return 1;
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}
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char *print_mac(char *buff, unsigned char *mac, int len)
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{
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char *p = buff;
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int i;
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if (len == 0)
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sprintf(p, "<null>");
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else
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for (i = 0; i < len; i++)
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p += sprintf(p, "%.2x%s", mac[i], (i == len - 1) ? "" : ":");
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return buff;
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|
}
|
|
|
|
void bump_maxfd(int fd, int *max)
|
|
{
|
|
if (fd > *max)
|
|
*max = fd;
|
|
}
|
|
|
|
int retry_send(void)
|
|
{
|
|
/* Linux kernels can return EAGAIN in perpetuity when calling
|
|
sendmsg() and the relevant interface has gone. Here we loop
|
|
retrying in EAGAIN for 1 second max, to avoid this hanging
|
|
dnsmasq. */
|
|
|
|
static int retries = 0;
|
|
struct timespec waiter;
|
|
|
|
if (errno == EAGAIN || errno == EWOULDBLOCK)
|
|
{
|
|
waiter.tv_sec = 0;
|
|
waiter.tv_nsec = 10000;
|
|
nanosleep(&waiter, NULL);
|
|
if (retries++ < 1000)
|
|
return 1;
|
|
}
|
|
|
|
retries = 0;
|
|
|
|
if (errno == EINTR)
|
|
return 1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
int read_write(int fd, unsigned char *packet, int size, int rw)
|
|
{
|
|
ssize_t n, done;
|
|
|
|
for (done = 0; done < size; done += n)
|
|
{
|
|
retry:
|
|
if (rw)
|
|
n = read(fd, &packet[done], (size_t)(size - done));
|
|
else
|
|
n = write(fd, &packet[done], (size_t)(size - done));
|
|
|
|
if (n == 0)
|
|
return 0;
|
|
else if (n == -1)
|
|
{
|
|
if (retry_send() || errno == ENOMEM || errno == ENOBUFS)
|
|
goto retry;
|
|
else
|
|
return 0;
|
|
}
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
/* Basically match a string value against a wildcard pattern. */
|
|
int wildcard_match(const char* wildcard, const char* match)
|
|
{
|
|
while (*wildcard && *match)
|
|
{
|
|
if (*wildcard == '*')
|
|
return 1;
|
|
|
|
if (*wildcard != *match)
|
|
return 0;
|
|
|
|
++wildcard;
|
|
++match;
|
|
}
|
|
|
|
return *wildcard == *match;
|
|
}
|
|
|
|
/* The same but comparing a maximum of NUM characters, like strncmp. */
|
|
int wildcard_matchn(const char* wildcard, const char* match, int num)
|
|
{
|
|
while (*wildcard && *match && num)
|
|
{
|
|
if (*wildcard == '*')
|
|
return 1;
|
|
|
|
if (*wildcard != *match)
|
|
return 0;
|
|
|
|
++wildcard;
|
|
++match;
|
|
--num;
|
|
}
|
|
|
|
return (!num) || (*wildcard == *match);
|
|
}
|