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FTL/src/dnsmasq/util.c

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/* dnsmasq is Copyright (c) 2000-2024 Simon Kelley
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 dated June, 1991, or
(at your option) version 3 dated 29 June, 2007.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/* The SURF random number generator was taken from djbdns-1.05, by
Daniel J Bernstein, which is public domain. */
#include "dnsmasq.h"
#ifdef HAVE_BROKEN_RTC
#include <sys/times.h>
#endif
#if defined(HAVE_LIBIDN2)
#include <idn2.h>
#elif defined(HAVE_IDN)
#include <idna.h>
#endif
#ifdef HAVE_LINUX_NETWORK
#include <sys/utsname.h>
#endif
/* SURF random number generator */
static u32 seed[32];
static u32 in[12];
static u32 out[8];
static int outleft = 0;
void rand_init()
{
int fd = open(RANDFILE, O_RDONLY);
if (fd == -1 ||
!read_write(fd, (unsigned char *)&seed, sizeof(seed), 1) ||
!read_write(fd, (unsigned char *)&in, sizeof(in), 1))
die(_("failed to seed the random number generator: %s"), NULL, EC_MISC);
close(fd);
}
#define ROTATE(x,b) (((x) << (b)) | ((x) >> (32 - (b))))
#define MUSH(i,b) x = t[i] += (((x ^ seed[i]) + sum) ^ ROTATE(x,b));
static void surf(void)
{
u32 t[12]; u32 x; u32 sum = 0;
int r; int i; int loop;
for (i = 0;i < 12;++i) t[i] = in[i] ^ seed[12 + i];
for (i = 0;i < 8;++i) out[i] = seed[24 + i];
x = t[11];
for (loop = 0;loop < 2;++loop) {
for (r = 0;r < 16;++r) {
sum += 0x9e3779b9;
MUSH(0,5) MUSH(1,7) MUSH(2,9) MUSH(3,13)
MUSH(4,5) MUSH(5,7) MUSH(6,9) MUSH(7,13)
MUSH(8,5) MUSH(9,7) MUSH(10,9) MUSH(11,13)
}
for (i = 0;i < 8;++i) out[i] ^= t[i + 4];
}
}
unsigned short rand16(void)
{
if (!outleft)
{
if (!++in[0]) if (!++in[1]) if (!++in[2]) ++in[3];
surf();
outleft = 8;
}
return (unsigned short) out[--outleft];
}
u32 rand32(void)
{
if (!outleft)
{
if (!++in[0]) if (!++in[1]) if (!++in[2]) ++in[3];
surf();
outleft = 8;
}
return out[--outleft];
}
u64 rand64(void)
{
static int outleft = 0;
if (outleft < 2)
{
if (!++in[0]) if (!++in[1]) if (!++in[2]) ++in[3];
surf();
outleft = 8;
}
outleft -= 2;
return (u64)out[outleft+1] + (((u64)out[outleft]) << 32);
}
int rr_on_list(struct rrlist *list, unsigned short rr)
{
while (list)
{
if (list->rr == rr || list->rr == T_ANY)
return 1;
list = list->next;
}
return 0;
}
/* returns 1 if name is OK and ascii printable
* returns 2 if name should be processed by IDN */
static int check_name(char *in)
{
/* remove trailing .
also fail empty string and label > 63 chars */
size_t dotgap = 0, l = strlen(in);
char c;
int nowhite = 0;
int idn_encode = 0;
int hasuscore = 0;
int hasucase = 0;
if (l == 0 || l > MAXDNAME) return 0;
if (in[l-1] == '.')
{
in[l-1] = 0;
nowhite = 1;
}
for (; (c = *in); in++)
{
if (c == '.')
dotgap = 0;
else if (++dotgap > MAXLABEL)
return 0;
else if (isascii((unsigned char)c) && iscntrl((unsigned char)c))
/* iscntrl only gives expected results for ascii */
return 0;
else if (!isascii((unsigned char)c))
#if !defined(HAVE_IDN) && !defined(HAVE_LIBIDN2)
return 0;
#else
idn_encode = 1;
#endif
else if (c != ' ')
{
nowhite = 1;
#if defined(HAVE_LIBIDN2) && (!defined(IDN2_VERSION_NUMBER) || IDN2_VERSION_NUMBER < 0x02000003)
if (c == '_')
hasuscore = 1;
#else
(void)hasuscore;
#endif
#if defined(HAVE_IDN) || defined(HAVE_LIBIDN2)
if (c >= 'A' && c <= 'Z')
hasucase = 1;
#else
(void)hasucase;
#endif
}
}
if (!nowhite)
return 0;
#if defined(HAVE_LIBIDN2) && (!defined(IDN2_VERSION_NUMBER) || IDN2_VERSION_NUMBER < 0x02000003)
/* Older libidn2 strips underscores, so don't do IDN processing
if the name has an underscore unless it also has non-ascii characters. */
idn_encode = idn_encode || (hasucase && !hasuscore);
#else
idn_encode = idn_encode || hasucase;
#endif
return (idn_encode) ? 2 : 1;
}
/* Hostnames have a more limited valid charset than domain names
so check for legal char a-z A-Z 0-9 - _
Note that this may receive a FQDN, so only check the first label
for the tighter criteria. */
int legal_hostname(char *name)
{
char c;
int first;
if (!check_name(name))
return 0;
for (first = 1; (c = *name); name++, first = 0)
/* check for legal char a-z A-Z 0-9 - _ . */
{
if ((c >= 'A' && c <= 'Z') ||
(c >= 'a' && c <= 'z') ||
(c >= '0' && c <= '9'))
continue;
if (!first && (c == '-' || c == '_'))
continue;
/* end of hostname part */
if (c == '.')
return 1;
return 0;
}
return 1;
}
char *canonicalise(char *in, int *nomem)
{
char *ret = NULL;
int rc;
if (nomem)
*nomem = 0;
if (!(rc = check_name(in)))
return NULL;
#if defined(HAVE_IDN) || defined(HAVE_LIBIDN2)
if (rc == 2)
{
# ifdef HAVE_LIBIDN2
rc = idn2_to_ascii_lz(in, &ret, IDN2_NONTRANSITIONAL);
# else
rc = idna_to_ascii_lz(in, &ret, 0);
# endif
if (rc != IDNA_SUCCESS)
{
if (ret)
free(ret);
if (nomem && (rc == IDNA_MALLOC_ERROR || rc == IDNA_DLOPEN_ERROR))
{
my_syslog(LOG_ERR, _("failed to allocate memory"));
*nomem = 1;
}
return NULL;
}
return ret;
}
#else
(void)rc;
#endif
if ((ret = whine_malloc(strlen(in)+1)))
strcpy(ret, in);
else if (nomem)
*nomem = 1;
return ret;
}
unsigned char *do_rfc1035_name(unsigned char *p, char *sval, char *limit)
{
int j;
while (sval && *sval)
{
unsigned char *cp = p++;
if (limit && p > (unsigned char*)limit)
return NULL;
for (j = 0; *sval && (*sval != '.'); sval++, j++)
{
if (limit && p + 1 > (unsigned char*)limit)
return NULL;
if (*sval == NAME_ESCAPE)
*p++ = (*(++sval))-1;
else
*p++ = *sval;
}
*cp = j;
if (*sval)
sval++;
}
return p;
}
/* for use during startup */
void *safe_malloc(size_t size)
{
void *ret = calloc(1, size);
if (!ret)
die(_("could not get memory"), NULL, EC_NOMEM);
return ret;
}
/* Ensure limited size string is always terminated.
* Can be replaced by (void)strlcpy() on some platforms */
void safe_strncpy(char *dest, const char *src, size_t size)
{
if (size != 0)
{
dest[size-1] = '\0';
strncpy(dest, src, size-1);
}
}
void safe_pipe(int *fd, int read_noblock)
{
if (pipe(fd) == -1 ||
!fix_fd(fd[1]) ||
(read_noblock && !fix_fd(fd[0])))
die(_("cannot create pipe: %s"), NULL, EC_MISC);
}
void *whine_malloc(size_t size)
{
void *ret = calloc(1, size);
if (!ret)
my_syslog(LOG_ERR, _("failed to allocate %d bytes"), (int) size);
return ret;
}
void *whine_realloc(void *ptr, size_t size)
{
void *ret = realloc(ptr, size);
if (!ret)
my_syslog(LOG_ERR, _("failed to reallocate %d bytes"), (int) size);
return ret;
}
int sockaddr_isequal(const union mysockaddr *s1, const union mysockaddr *s2)
{
if (s1->sa.sa_family == s2->sa.sa_family)
{
if (s1->sa.sa_family == AF_INET &&
s1->in.sin_port == s2->in.sin_port &&
s1->in.sin_addr.s_addr == s2->in.sin_addr.s_addr)
return 1;
if (s1->sa.sa_family == AF_INET6 &&
s1->in6.sin6_port == s2->in6.sin6_port &&
s1->in6.sin6_scope_id == s2->in6.sin6_scope_id &&
IN6_ARE_ADDR_EQUAL(&s1->in6.sin6_addr, &s2->in6.sin6_addr))
return 1;
}
return 0;
}
int sockaddr_isnull(const union mysockaddr *s)
{
if (s->sa.sa_family == AF_INET &&
s->in.sin_addr.s_addr == 0)
return 1;
if (s->sa.sa_family == AF_INET6 &&
IN6_IS_ADDR_UNSPECIFIED(&s->in6.sin6_addr))
return 1;
return 0;
}
int sa_len(union mysockaddr *addr)
{
#ifdef HAVE_SOCKADDR_SA_LEN
return addr->sa.sa_len;
#else
if (addr->sa.sa_family == AF_INET6)
return sizeof(addr->in6);
else
return sizeof(addr->in);
#endif
}
/* don't use strcasecmp and friends here - they may be messed up by LOCALE */
int hostname_order(const char *a, const char *b)
{
unsigned int c1, c2;
do {
c1 = (unsigned char) *a++;
c2 = (unsigned char) *b++;
if (c1 >= 'A' && c1 <= 'Z')
c1 += 'a' - 'A';
if (c2 >= 'A' && c2 <= 'Z')
c2 += 'a' - 'A';
if (c1 < c2)
return -1;
else if (c1 > c2)
return 1;
} while (c1);
return 0;
}
int hostname_isequal(const char *a, const char *b)
{
return hostname_order(a, b) == 0;
}
/* is b equal to or a subdomain of a return 2 for equal, 1 for subdomain */
int hostname_issubdomain(char *a, char *b)
{
char *ap, *bp;
unsigned int c1, c2;
/* move to the end */
for (ap = a; *ap; ap++);
for (bp = b; *bp; bp++);
/* a shorter than b or a empty. */
if ((bp - b) < (ap - a) || ap == a)
return 0;
do
{
c1 = (unsigned char) *(--ap);
c2 = (unsigned char) *(--bp);
if (c1 >= 'A' && c1 <= 'Z')
c1 += 'a' - 'A';
if (c2 >= 'A' && c2 <= 'Z')
c2 += 'a' - 'A';
if (c1 != c2)
return 0;
} while (ap != a);
if (bp == b)
return 2;
if (*(--bp) == '.')
return 1;
return 0;
}
time_t dnsmasq_time(void)
{
#ifdef HAVE_BROKEN_RTC
struct timespec ts;
if (clock_gettime(CLOCK_MONOTONIC, &ts) < 0)
die(_("cannot read monotonic clock: %s"), NULL, EC_MISC);
return ts.tv_sec;
#else
return time(NULL);
#endif
}
u32 dnsmasq_milliseconds(void)
{
struct timeval tv;
gettimeofday(&tv, NULL);
return (tv.tv_sec) * 1000 + (tv.tv_usec / 1000);
}
int netmask_length(struct in_addr mask)
{
int zero_count = 0;
while (0x0 == (mask.s_addr & 0x1) && zero_count < 32)
{
mask.s_addr >>= 1;
zero_count++;
}
return 32 - zero_count;
}
int is_same_net(struct in_addr a, struct in_addr b, struct in_addr mask)
{
return (a.s_addr & mask.s_addr) == (b.s_addr & mask.s_addr);
}
int is_same_net_prefix(struct in_addr a, struct in_addr b, int prefix)
{
struct in_addr mask;
mask.s_addr = htonl(~((1 << (32 - prefix)) - 1));
return is_same_net(a, b, mask);
}
int is_same_net6(struct in6_addr *a, struct in6_addr *b, int prefixlen)
{
int pfbytes = prefixlen >> 3;
int pfbits = prefixlen & 7;
if (memcmp(&a->s6_addr, &b->s6_addr, pfbytes) != 0)
return 0;
if (pfbits == 0 ||
(a->s6_addr[pfbytes] >> (8 - pfbits) == b->s6_addr[pfbytes] >> (8 - pfbits)))
return 1;
return 0;
}
/* return least significant 64 bits if IPv6 address */
u64 addr6part(struct in6_addr *addr)
{
int i;
u64 ret = 0;
for (i = 8; i < 16; i++)
ret = (ret << 8) + addr->s6_addr[i];
return ret;
}
void setaddr6part(struct in6_addr *addr, u64 host)
{
int i;
for (i = 15; i >= 8; i--)
{
addr->s6_addr[i] = host;
host = host >> 8;
}
}
/* returns port number from address */
int prettyprint_addr(union mysockaddr *addr, char *buf)
{
int port = 0;
if (addr->sa.sa_family == AF_INET)
{
inet_ntop(AF_INET, &addr->in.sin_addr, buf, ADDRSTRLEN);
port = ntohs(addr->in.sin_port);
}
else if (addr->sa.sa_family == AF_INET6)
{
char name[IF_NAMESIZE];
inet_ntop(AF_INET6, &addr->in6.sin6_addr, buf, ADDRSTRLEN);
if (addr->in6.sin6_scope_id != 0 &&
if_indextoname(addr->in6.sin6_scope_id, name) &&
strlen(buf) + strlen(name) + 2 <= ADDRSTRLEN)
{
strcat(buf, "%");
strcat(buf, name);
}
port = ntohs(addr->in6.sin6_port);
}
return port;
}
void prettyprint_time(char *buf, unsigned int t)
{
if (t == 0xffffffff)
sprintf(buf, _("infinite"));
else
{
unsigned int x, p = 0;
if ((x = t/86400))
p += sprintf(&buf[p], "%ud", x);
if ((x = (t/3600)%24))
p += sprintf(&buf[p], "%uh", x);
if ((x = (t/60)%60))
p += sprintf(&buf[p], "%um", x);
if ((x = t%60))
sprintf(&buf[p], "%us", x);
}
}
/* in may equal out, when maxlen may be -1 (No max len).
Return -1 for extraneous no-hex chars found. */
int parse_hex(char *in, unsigned char *out, int maxlen,
unsigned int *wildcard_mask, int *mac_type)
{
int done = 0, mask = 0, i = 0;
char *r;
if (mac_type)
*mac_type = 0;
while (!done && (maxlen == -1 || i < maxlen))
{
for (r = in; *r != 0 && *r != ':' && *r != '-' && *r != ' '; r++)
if (*r != '*' && !isxdigit((unsigned char)*r))
return -1;
if (*r == 0)
done = 1;
if (r != in )
{
if (*r == '-' && i == 0 && mac_type)
{
*r = 0;
*mac_type = strtol(in, NULL, 16);
mac_type = NULL;
}
else
{
*r = 0;
if (strcmp(in, "*") == 0)
{
mask = (mask << 1) | 1;
i++;
}
else
{
int j, bytes = (1 + (r - in))/2;
for (j = 0; j < bytes; j++)
{
char sav;
if (j < bytes - 1)
{
sav = in[(j+1)*2];
in[(j+1)*2] = 0;
}
/* checks above allow mix of hexdigit and *, which
is illegal. */
if (strchr(&in[j*2], '*'))
return -1;
out[i] = strtol(&in[j*2], NULL, 16);
mask = mask << 1;
if (++i == maxlen)
break;
if (j < bytes - 1)
in[(j+1)*2] = sav;
}
}
}
}
in = r+1;
}
if (wildcard_mask)
*wildcard_mask = mask;
return i;
}
/* return 0 for no match, or (no matched octets) + 1 */
int memcmp_masked(unsigned char *a, unsigned char *b, int len, unsigned int mask)
{
int i, count;
for (count = 1, i = len - 1; i >= 0; i--, mask = mask >> 1)
if (!(mask & 1))
{
if (a[i] == b[i])
count++;
else
return 0;
}
return count;
}
/* _note_ may copy buffer */
int expand_buf(struct iovec *iov, size_t size)
{
void *new;
if (size <= (size_t)iov->iov_len)
return 1;
if (!(new = whine_malloc(size)))
{
errno = ENOMEM;
return 0;
}
if (iov->iov_base)
{
memcpy(new, iov->iov_base, iov->iov_len);
free(iov->iov_base);
}
iov->iov_base = new;
iov->iov_len = size;
return 1;
}
char *print_mac(char *buff, unsigned char *mac, int len)
{
char *p = buff;
int i;
if (len == 0)
sprintf(p, "<null>");
else
for (i = 0; i < len; i++)
p += sprintf(p, "%.2x%s", mac[i], (i == len - 1) ? "" : ":");
return buff;
}
/* rc is return from sendto and friends.
Return 1 if we should retry.
Set errno to zero if we succeeded. */
int retry_send(ssize_t rc)
{
static int retries = 0;
struct timespec waiter;
if (rc != -1)
{
retries = 0;
errno = 0;
return 0;
}
/* 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. */
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)
{
do {
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;
} while (retry_send(n) || errno == ENOMEM || errno == ENOBUFS);
if (errno != 0)
return 0;
}
return 1;
}
/* close all fds except STDIN, STDOUT and STDERR, spare1, spare2 and spare3 */
void close_fds(long max_fd, int spare1, int spare2, int spare3)
{
/* On Linux, use the /proc/ filesystem to find which files
are actually open, rather than iterate over the whole space,
for efficiency reasons. If this fails we drop back to the dumb code. */
#ifdef HAVE_LINUX_NETWORK
DIR *d;
if ((d = opendir("/proc/self/fd")))
{
struct dirent *de;
while ((de = readdir(d)))
{
long fd;
char *e = NULL;
errno = 0;
fd = strtol(de->d_name, &e, 10);
if (errno != 0 || !e || *e || fd == dirfd(d) ||
fd == STDOUT_FILENO || fd == STDERR_FILENO || fd == STDIN_FILENO ||
fd == spare1 || fd == spare2 || fd == spare3)
continue;
close(fd);
}
closedir(d);
return;
}
#endif
/* fallback, dumb code. */
for (max_fd--; max_fd >= 0; max_fd--)
if (max_fd != STDOUT_FILENO && max_fd != STDERR_FILENO && max_fd != STDIN_FILENO &&
max_fd != spare1 && max_fd != spare2 && max_fd != spare3)
close(max_fd);
}
/* 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);
}
#ifdef HAVE_LINUX_NETWORK
int kernel_version(void)
{
struct utsname utsname;
int version;
char *split;
if (uname(&utsname) < 0)
die(_("failed to find kernel version: %s"), NULL, EC_MISC);
split = strtok(utsname.release, ".");
version = (split ? atoi(split) : 0);
split = strtok(NULL, ".");
version = version * 256 + (split ? atoi(split) : 0);
split = strtok(NULL, ".");
return version * 256 + (split ? atoi(split) : 0);
}
#endif
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