add route

kernel_add_route (struct prefix_ipv4 *dest, struct in_addr *gate,
                  int index, int flags)
{
  int ret;
  int sock;
  struct rtentry rtentry;
  struct sockaddr_in sin_dest, sin_mask, sin_gate;

  memset (&rtentry, 0, sizeof (struct rtentry));

  /* Make destination. */
  memset (&sin_dest, 0, sizeof (struct sockaddr_in));
  sin_dest.sin_family = AF_INET;
#ifdef HAVE_SIN_LEN
  sin_dest.sin_len = sizeof (struct sockaddr_in);
#endif /* HAVE_SIN_LEN */
  sin_dest.sin_addr = dest->prefix;

  /* Make gateway. */
  if (gate)
    {
      memset (&sin_gate, 0, sizeof (struct sockaddr_in));
      sin_gate.sin_family = AF_INET;
#ifdef HAVE_SIN_LEN
      sin_gate.sin_len = sizeof (struct sockaddr_in);
#endif /* HAVE_SIN_LEN */
      sin_gate.sin_addr = *gate;
    }

  memset (&sin_mask, 0, sizeof (struct sockaddr_in));
  sin_mask.sin_family = AF_INET;
#ifdef HAVE_SIN_LEN
      sin_gate.sin_len = sizeof (struct sockaddr_in);
#endif /* HAVE_SIN_LEN */
  masklen2ip (dest->prefixlen, &sin_mask.sin_addr);

  /* Set destination address, mask and gateway.*/
  memcpy (&rtentry.rt_dst, &sin_dest, sizeof (struct sockaddr_in));
  if (gate)
    memcpy (&rtentry.rt_gateway, &sin_gate, sizeof (struct sockaddr_in));
#ifndef SUNOS_5
  memcpy (&rtentry.rt_genmask, &sin_mask, sizeof (struct sockaddr_in));
#endif /* SUNOS_5 */

  /* Routing entry flag set. */
  if (dest->prefixlen == 32)
    rtentry.rt_flags |= RTF_HOST;

  if (gate && gate->s_addr != INADDR_ANY)
    rtentry.rt_flags |= RTF_GATEWAY;

  rtentry.rt_flags |= RTF_UP;

  /* Additional flags */
  rtentry.rt_flags |= flags;

  /* For tagging route. */
  /* rtentry.rt_flags |= RTF_DYNAMIC; */

  /* Open socket for ioctl. */
  sock = socket (AF_INET, SOCK_DGRAM, 0);
  if (sock < 0)
    {
      zlog_warn ("can't make socket/n");
      return -1;
    }

  /* Send message by ioctl(). */
  ret = ioctl (sock, SIOCADDRT, &rtentry);
  if (ret < 0)
    {
      switch (errno)
        {
        case EEXIST:
          close (sock);
          return ZEBRA_ERR_RTEXIST;
          break;
        case ENETUNREACH:
          close (sock);
          return ZEBRA_ERR_RTUNREACH;
          break;
        case EPERM:
          close (sock);
          return ZEBRA_ERR_EPERM;
          break;
        }

      close (sock);
      zlog_warn ("write : %s (%d)", strerror (errno), errno);
      return 1;
    }
  close (sock);

  return ret;
}