tun.c

一个开源的VPN原码

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 */

#else

void
open_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 */

void
close_tun (struct tuntap *tt)
{
  close_tun_generic (tt);
}

int
write_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);
}

int
read_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)

void
open_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. 
 */
void
close_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);
}

int
write_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;
}

int
read_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)

void
open_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);
}

void
close_tun (struct tuntap* tt)
{
  close_tun_generic (tt);
}

static inline int
openbsd_modify_read_write_return (int len)
{
 if (len > 0)
    return len > sizeof (u_int32_t) ? len - sizeof (u_int32_t) : 0;
  else
    return len;
}

int
write_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));
}

int
read_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)

void
open_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);
    }
}

void
close_tun (struct tuntap* tt)
{
  close_tun_generic (tt);
}

int
write_tun (struct tuntap* tt, uint8_t *buf, int len)
{
  return write (tt->fd, buf, len);
}

int
read_tun (struct tuntap* tt, uint8_t *buf, int len)
{
  return read (tt->fd, buf, len);
}

#else /* generic */

void
open_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);
}

void
close_tun (struct tuntap* tt)
{
  close_tun_generic (tt);
}

int
write_tun (struct tuntap* tt, uint8_t *buf, int len)
{
  return write (tt->fd, buf, len);
}

int
read_tun (struct tuntap* tt, uint8_t *buf, int len)
{
  return read (tt->fd, buf, len);
}

#endif