tuncfg (const char *dev, const char *dev_type, const char *dev_node, bool ipv6, int persist_mode){  struct tuntap tt;  open_tun (dev, dev_type, dev_node, ipv6, &tt);  if (ioctl (tt.fd, TUNSETPERSIST, persist_mode) < 0)    msg (M_ERR, "Cannot ioctl TUNSETPERSIST(%d) %s", persist_mode, dev);  close_tun (&tt);  msg (M_INFO, "Persist state set to: %s", (persist_mode ? "ON" : "OFF"));}#endif /* TUNSETPERSIST */#elsevoidopen_tun (const char *dev, const char *dev_type, const char *dev_node, bool ipv6,	  struct tuntap *tt){  open_tun_generic (dev, dev_node, ipv6, false, tt);}#endif /* HAVE_LINUX_IF_TUN_H */voidclose_tun (struct tuntap *tt){  close_tun_generic (tt);}intwrite_tun (struct tuntap* tt, uint8_t *buf, int len){#if LINUX_IPV6  if (tt->ipv6)    {      struct tun_pi pi;      struct iphdr *iph;      struct iovec vect[2];      int ret;      iph = (struct iphdr *)buf;      pi.flags = 0;      if(iph->version == 6)	pi.proto = htons(ETH_P_IPV6);      else	pi.proto = htons(ETH_P_IP);      vect[0].iov_len = sizeof(pi);      vect[0].iov_base = &pi;      vect[1].iov_len = len;      vect[1].iov_base = buf;      ret = writev(tt->fd, vect, 2);      return(ret - sizeof(pi));    }  else#endif    return write (tt->fd, buf, len);}intread_tun (struct tuntap* tt, uint8_t *buf, int len){#if LINUX_IPV6  if (tt->ipv6)    {      struct iovec vect[2];      struct tun_pi pi;      int ret;      vect[0].iov_len = sizeof(pi);      vect[0].iov_base = &pi;      vect[1].iov_len = len;      vect[1].iov_base = buf;      ret = readv(tt->fd, vect, 2);      return(ret - sizeof(pi));    }  else#endif    return read (tt->fd, buf, len);}#elif defined(TARGET_SOLARIS)voidopen_tun (const char *dev, const char *dev_type, const char *dev_node, bool ipv6,	  struct tuntap *tt){  int if_fd, muxid, ppa = -1;  struct ifreq ifr;  const char *ptr;  const char *ip_node;  const char *dev_tuntap_type;  int link_type;  bool is_tun;  clear_tuntap (tt);  ipv6_support (ipv6, false, tt);  if (!strcmp(dev, "null"))    {      open_null (tt);      return;    }  if (is_dev_type (dev, dev_type, "tun"))    {      ip_node = "/dev/udp";      if (!dev_node)	dev_node = "/dev/tun";      dev_tuntap_type = "tun";      link_type = I_PLINK;      is_tun = true;    }  else if (is_dev_type (dev, dev_type, "tap"))    {      ip_node = "/dev/ip";      if (!dev_node)	dev_node = "/dev/tap";      dev_tuntap_type = "tap";      link_type = I_PLINK; /* was: I_LINK */      is_tun = false;    }  else    {      msg (M_FATAL, "I don't recognize device %s as a tun or tap device",	   dev);    }    /* get unit number */  if (*dev)    {      ptr = dev;      while (*ptr && !isdigit ((int) *ptr))	ptr++;      ppa = atoi (ptr);    }  if ((tt->ip_fd = open (ip_node, O_RDWR, 0)) < 0)    msg (M_ERR, "Can't open %s", ip_node);  if ((tt->fd = open (dev_node, O_RDWR, 0)) < 0)    msg (M_ERR, "Can't open %s", dev_node);  /* Assign a new PPA and get its unit number. */  if ((ppa = ioctl (tt->fd, TUNNEWPPA, ppa)) < 0)    msg (M_ERR, "Can't assign new interface");  if ((if_fd = open (dev_node, O_RDWR, 0)) < 0)    msg (M_ERR, "Can't open %s (2)", dev_node);  if (ioctl (if_fd, I_PUSH, "ip") < 0)    msg (M_ERR, "Can't push IP module");  /* Assign ppa according to the unit number returned by tun device */  if (ioctl (if_fd, IF_UNITSEL, (char *) &ppa) < 0)    msg (M_ERR, "Can't set PPA %d", ppa);  if ((muxid = ioctl (tt->ip_fd, link_type, if_fd)) < 0)    msg (M_ERR, "Can't link %s device to IP", dev_tuntap_type);  close (if_fd);  snprintf (tt->actual, sizeof (tt->actual), "%s%d", dev_tuntap_type, ppa);  CLEAR (ifr);  strncpynt (ifr.ifr_name, tt->actual, sizeof (ifr.ifr_name));  ifr.ifr_ip_muxid = muxid;  if (ioctl (tt->ip_fd, SIOCSIFMUXID, &ifr) < 0)    {      ioctl (tt->ip_fd, I_PUNLINK, muxid);      msg (M_ERR, "Can't set multiplexor id");    }  set_nonblock (tt->fd);}/* * Close TUN device.  */voidclose_tun (struct tuntap* tt){  if (tt->fd >= 0)    {      struct ifreq ifr;      CLEAR (ifr);      strncpynt (ifr.ifr_name, tt->actual, sizeof (ifr.ifr_name));     if (ioctl (tt->ip_fd, SIOCGIFFLAGS, &ifr) < 0)	msg (M_ERR, "Can't get iface flags");      if (ioctl (tt->ip_fd, SIOCGIFMUXID, &ifr) < 0)	msg (M_ERR, "Can't get multiplexor id");      if (ioctl (tt->ip_fd, I_PUNLINK, ifr.ifr_ip_muxid) < 0)	msg (M_ERR, "Can't unlink interface");      close (tt->ip_fd);      close (tt->fd);    }  clear_tuntap (tt);}intwrite_tun (struct tuntap* tt, uint8_t *buf, int len){  struct strbuf sbuf;  sbuf.len = len;  sbuf.buf = buf;  return putmsg (tt->fd, NULL, &sbuf, 0) >= 0 ? sbuf.len : -1;}intread_tun (struct tuntap* tt, uint8_t *buf, int len){  struct strbuf sbuf;  int f = 0;  sbuf.maxlen = len;  sbuf.buf = buf;  return getmsg (tt->fd, NULL, &sbuf, &f) >= 0 ? sbuf.len : -1;}#elif defined(TARGET_OPENBSD)voidopen_tun (const char *dev, const char *dev_type, const char *dev_node, bool ipv6,	  struct tuntap *tt){  open_tun_generic (dev, dev_node, ipv6, false, tt);}voidclose_tun (struct tuntap* tt){  close_tun_generic (tt);}static inline intopenbsd_modify_read_write_return (int len){ if (len > 0)    return len > sizeof (u_int32_t) ? len - sizeof (u_int32_t) : 0;  else    return len;}intwrite_tun (struct tuntap* tt, uint8_t *buf, int len){  u_int32_t type = htonl (AF_INET);  struct iovec iv[2];  iv[0].iov_base = &type;  iv[0].iov_len = sizeof (type);  iv[1].iov_base = buf;  iv[1].iov_len = len;  return openbsd_modify_read_write_return (writev (tt->fd, iv, 2));}intread_tun (struct tuntap* tt, uint8_t *buf, int len){  u_int32_t type;  struct iovec iv[2];  iv[0].iov_base = &type;  iv[0].iov_len = sizeof (type);  iv[1].iov_base = buf;  iv[1].iov_len = len;  return openbsd_modify_read_write_return (readv (tt->fd, iv, 2));}#elif defined(TARGET_FREEBSD)voidopen_tun (const char *dev, const char *dev_type, const char *dev_node, bool ipv6,	  struct tuntap *tt){  open_tun_generic (dev, dev_node, ipv6, false, tt);  if (tt->fd >= 0)    {      int i = 0;      /* Disable extended modes */      ioctl (tt->fd, TUNSLMODE, &i);      ioctl (tt->fd, TUNSIFHEAD, &i);    }}voidclose_tun (struct tuntap* tt){  close_tun_generic (tt);}intwrite_tun (struct tuntap* tt, uint8_t *buf, int len){  return write (tt->fd, buf, len);}intread_tun (struct tuntap* tt, uint8_t *buf, int len){  return read (tt->fd, buf, len);}#else /* generic */voidopen_tun (const char *dev, const char *dev_type, const char *dev_node, bool ipv6,	  struct tuntap *tt){  open_tun_generic (dev, dev_node, ipv6, false, tt);}voidclose_tun (struct tuntap* tt){  close_tun_generic (tt);}intwrite_tun (struct tuntap* tt, uint8_t *buf, int len){  return write (tt->fd, buf, len);}intread_tun (struct tuntap* tt, uint8_t *buf, int len){  return read (tt->fd, buf, len);}#endif