util.c

   1 /*
   2  * Copyright (C) 2014 John Crispin <blogic@openwrt.org>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU Lesser General Public License version 2.1
   6  * as published by the Free Software Foundation
   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
  14 #include <sys/socket.h>
  15 #include <sys/ioctl.h>
  16 #include <sys/types.h>
  17 #include <sys/stat.h>
  18 #include <sys/utsname.h>
  19 #include <linux/if.h>
  20 #include <linux/sockios.h>
  21 #include <arpa/inet.h>
  22
  23 #include <unistd.h>
  24 #include <stdio.h>
  25 #include <string.h>
  26 #include <errno.h>
  27 #include <fcntl.h>
  28 #include <stdlib.h>
  29 #include <signal.h>
  30
  31 #include <libubox/uloop.h>
  32
  33 #include "dns.h"
  34 #include "util.h"
  35
  36 uint8_t mdns_buf[MDNS_BUF_LEN];
  37 int debug = 0;
  38
  39 char mdns_hostname[HOSTNAME_LEN];
  40 char mdns_hostname_local[HOSTNAME_LEN + 6];
  41
  42 static void
  43 signal_shutdown(int signal)
  44 {
  45         uloop_end();
  46 }
  47
  48 void
  49 signal_setup(void)
  50 {
  51         signal(SIGPIPE, SIG_IGN);
  52         signal(SIGTERM, signal_shutdown);
  53         signal(SIGKILL, signal_shutdown);
  54 }
  55
  56 uint32_t
  57 rand_time_delta(uint32_t t)
  58 {
  59         uint32_t val;
  60         int fd = open("/dev/urandom", O_RDONLY);
  61
  62         if (!fd)
  63                 return t;
  64
  65         if (read(fd, &val, sizeof(val)) == sizeof(val)) {
  66                 int range = t / 30;
  67
  68                 srand(val);
  69                 val = t + (rand() % range) - (range / 2);
  70         } else {
  71                 val = t;
  72         }
  73
  74         close(fd);
  75
  76         return val;
  77 }
  78
  79 void get_hostname(void)
  80 {
  81         struct utsname utsname;
  82
  83         mdns_hostname[0] = 0;
  84         mdns_hostname_local[0] = 0;
  85
  86         if (uname(&utsname) < 0)
  87                 return;
  88
  89         snprintf(mdns_hostname, sizeof(mdns_hostname), "%s", utsname.nodename);
  90         snprintf(mdns_hostname_local, sizeof(mdns_hostname_local), "%s.local", utsname.nodename);
  91 }
  92
  93 void*
  94 memdup(const void *d, int l)
  95 {
  96         void *r = malloc(l);
  97         if (!r)
  98                 return NULL;
  99         memcpy(r, d, l);
 100         return r;
 101 }
 102