tun.c

tun虚拟网卡设备源码

}

#elif defined(WIN32)

int
tun_read_queue (struct tuntap *tt, int maxsize)
{
  if (tt->reads.iostate == IOSTATE_INITIAL)
    {
      DWORD len;
      BOOL status;
      int err;

      /* reset buf to its initial state */
      tt->reads.buf = tt->reads.buf_init;

      len = maxsize ? maxsize : BLEN (&tt->reads.buf);
      ASSERT (len <= BLEN (&tt->reads.buf));

      /* the overlapped read will signal this event on I/O completion */
      ASSERT (ResetEvent (tt->reads.overlapped.hEvent));

      status = ReadFile(
		      tt->hand,
		      BPTR (&tt->reads.buf),
		      len,
		      &tt->reads.size,
		      &tt->reads.overlapped
		      );

      if (status) /* operation completed immediately? */
	{
	  /* since we got an immediate return, we must signal the event object ourselves */
	  ASSERT (SetEvent (tt->reads.overlapped.hEvent));

	  tt->reads.iostate = IOSTATE_IMMEDIATE_RETURN;
	  tt->reads.status = 0;

	  dmsg (D_WIN32_IO, "WIN32 I/O: TAP Read immediate return [%d,%d]",
	       (int) len,
	       (int) tt->reads.size);	       
	}
      else
	{
	  err = GetLastError (); 
	  if (err == ERROR_IO_PENDING) /* operation queued? */
	    {
	      tt->reads.iostate = IOSTATE_QUEUED;
	      tt->reads.status = err;
	      dmsg (D_WIN32_IO, "WIN32 I/O: TAP Read queued [%d]",
		   (int) len);
	    }
	  else /* error occurred */
	    {
	      struct gc_arena gc = gc_new ();
	      ASSERT (SetEvent (tt->reads.overlapped.hEvent));
	      tt->reads.iostate = IOSTATE_IMMEDIATE_RETURN;
	      tt->reads.status = err;
	      dmsg (D_WIN32_IO, "WIN32 I/O: TAP Read error [%d] : %s",
		   (int) len,
		   strerror_win32 (status, &gc));
	      gc_free (&gc);
	    }
	}
    }
  return tt->reads.iostate;
}

int
tun_write_queue (struct tuntap *tt, struct buffer *buf)
{
  if (tt->writes.iostate == IOSTATE_INITIAL)
    {
      BOOL status;
      int err;
 
      /* make a private copy of buf */
      tt->writes.buf = tt->writes.buf_init;
      tt->writes.buf.len = 0;
      ASSERT (buf_copy (&tt->writes.buf, buf));

      /* the overlapped write will signal this event on I/O completion */
      ASSERT (ResetEvent (tt->writes.overlapped.hEvent));

      status = WriteFile(
			tt->hand,
			BPTR (&tt->writes.buf),
			BLEN (&tt->writes.buf),
			&tt->writes.size,
			&tt->writes.overlapped
			);

      if (status) /* operation completed immediately? */
	{
	  tt->writes.iostate = IOSTATE_IMMEDIATE_RETURN;

	  /* since we got an immediate return, we must signal the event object ourselves */
	  ASSERT (SetEvent (tt->writes.overlapped.hEvent));

	  tt->writes.status = 0;

	  dmsg (D_WIN32_IO, "WIN32 I/O: TAP Write immediate return [%d,%d]",
	       BLEN (&tt->writes.buf),
	       (int) tt->writes.size);	       
	}
      else
	{
	  err = GetLastError (); 
	  if (err == ERROR_IO_PENDING) /* operation queued? */
	    {
	      tt->writes.iostate = IOSTATE_QUEUED;
	      tt->writes.status = err;
	      dmsg (D_WIN32_IO, "WIN32 I/O: TAP Write queued [%d]",
		   BLEN (&tt->writes.buf));
	    }
	  else /* error occurred */
	    {
	      struct gc_arena gc = gc_new ();
	      ASSERT (SetEvent (tt->writes.overlapped.hEvent));
	      tt->writes.iostate = IOSTATE_IMMEDIATE_RETURN;
	      tt->writes.status = err;
	      dmsg (D_WIN32_IO, "WIN32 I/O: TAP Write error [%d] : %s",
		   BLEN (&tt->writes.buf),
		   strerror_win32 (err, &gc));
	      gc_free (&gc);
	    }
	}
    }
  return tt->writes.iostate;
}

int
tun_finalize (
	      HANDLE h,
	      struct overlapped_io *io,
	      struct buffer *buf)
{
  int ret = -1;
  BOOL status;

  switch (io->iostate)
    {
    case IOSTATE_QUEUED:
      status = GetOverlappedResult(
				   h,
				   &io->overlapped,
				   &io->size,
				   FALSE
				   );
      if (status)
	{
	  /* successful return for a queued operation */
	  if (buf)
	    *buf = io->buf;
	  ret = io->size;
	  io->iostate = IOSTATE_INITIAL;
	  ASSERT (ResetEvent (io->overlapped.hEvent));
	  dmsg (D_WIN32_IO, "WIN32 I/O: TAP Completion success [%d]", ret);
	}
      else
	{
	  /* error during a queued operation */
	  ret = -1;
	  if (GetLastError() != ERROR_IO_INCOMPLETE)
	    {
	      /* if no error (i.e. just not finished yet),
		 then DON'T execute this code */
	      io->iostate = IOSTATE_INITIAL;
	      ASSERT (ResetEvent (io->overlapped.hEvent));
	      msg (D_WIN32_IO | M_ERRNO, "WIN32 I/O: TAP Completion error");
	    }
	}
      break;

    case IOSTATE_IMMEDIATE_RETURN:
      io->iostate = IOSTATE_INITIAL;
      ASSERT (ResetEvent (io->overlapped.hEvent));
      if (io->status)
	{
	  /* error return for a non-queued operation */
	  SetLastError (io->status);
	  ret = -1;
	  msg (D_WIN32_IO | M_ERRNO, "WIN32 I/O: TAP Completion non-queued error");
	}
      else
	{
	  /* successful return for a non-queued operation */
	  if (buf)
	    *buf = io->buf;
	  ret = io->size;
	  dmsg (D_WIN32_IO, "WIN32 I/O: TAP Completion non-queued success [%d]", ret);
	}
      break;

    case IOSTATE_INITIAL: /* were we called without proper queueing? */
      SetLastError (ERROR_INVALID_FUNCTION);
      ret = -1;
      dmsg (D_WIN32_IO, "WIN32 I/O: TAP Completion BAD STATE");
      break;

    default:
      ASSERT (0);
    }

  if (buf)
    buf->len = ret;
  return ret;
}

const struct tap_reg *
get_tap_reg (struct gc_arena *gc)
{
  HKEY adapter_key;
  LONG status;
  DWORD len;
  struct tap_reg *first = NULL;
  struct tap_reg *last = NULL;
  int i = 0;

  status = RegOpenKeyEx(
			HKEY_LOCAL_MACHINE,
			ADAPTER_KEY,
			0,
			KEY_READ,
			&adapter_key);

  if (status != ERROR_SUCCESS)
    msg (M_FATAL, "Error opening registry key: %s", ADAPTER_KEY);

  while (true)
    {
      char enum_name[256];
      char unit_string[256];
      HKEY unit_key;
      char component_id_string[] = "ComponentId";
      char component_id[256];
      char net_cfg_instance_id_string[] = "NetCfgInstanceId";
      char net_cfg_instance_id[256];
      DWORD data_type;

      len = sizeof (enum_name);
      status = RegEnumKeyEx(
			    adapter_key,
			    i,
			    enum_name,
			    &len,
			    NULL,
			    NULL,
			    NULL,
			    NULL);
      if (status == ERROR_NO_MORE_ITEMS)
	break;
      else if (status != ERROR_SUCCESS)
	msg (M_FATAL, "Error enumerating registry subkeys of key: %s",
	     ADAPTER_KEY);

      openvpn_snprintf (unit_string, sizeof(unit_string), "%s\\%s",
			ADAPTER_KEY, enum_name);

      status = RegOpenKeyEx(
			    HKEY_LOCAL_MACHINE,
			    unit_string,
			    0,
			    KEY_READ,
			    &unit_key);

      if (status != ERROR_SUCCESS)
	dmsg (D_REGISTRY, "Error opening registry key: %s", unit_string);
      else
	{
	  len = sizeof (component_id);
	  status = RegQueryValueEx(
				   unit_key,
				   component_id_string,
				   NULL,
				   &data_type,
				   component_id,
				   &len);

	  if (status != ERROR_SUCCESS || data_type != REG_SZ)
	    dmsg (D_REGISTRY, "Error opening registry key: %s\\%s",
		 unit_string, component_id_string);
	  else
	    {	      
	      len = sizeof (net_cfg_instance_id);
	      status = RegQueryValueEx(
				       unit_key,
				       net_cfg_instance_id_string,
				       NULL,
				       &data_type,
				       net_cfg_instance_id,
				       &len);

	      if (status == ERROR_SUCCESS && data_type == REG_SZ)
		{
		  if (!strcmp (component_id, TAP_COMPONENT_ID))
		    {
		      struct tap_reg *reg;
		      ALLOC_OBJ_CLEAR_GC (reg, struct tap_reg, gc);
		      reg->guid = string_alloc (net_cfg_instance_id, gc);
		      
		      /* link into return list */
		      if (!first)
			first = reg;
		      if (last)
			last->next = reg;
		      last = reg;
		    }
		}
	    }
	  RegCloseKey (unit_key);
	}
      ++i;
    }

  RegCloseKey (adapter_key);
  return first;
}

const struct panel_reg *
get_panel_reg (struct gc_arena *gc)
{
  LONG status;
  HKEY network_connections_key;
  DWORD len;
  struct panel_reg *first = NULL;
  struct panel_reg *last = NULL;
  int i = 0;

  status = RegOpenKeyEx(
			HKEY_LOCAL_MACHINE,
			NETWORK_CONNECTIONS_KEY,
			0,
			KEY_READ,
			&network_connections_key);

  if (status != ERROR_SUCCESS)
    msg (M_FATAL, "Error opening registry key: %s", NETWORK_CONNECTIONS_KEY);

  while (true)
    {
      char enum_name[256];
      char connection_string[256];
      HKEY connection_key;
      char name_data[256];
      DWORD name_type;
      const char name_string[] = "Name";

      len = sizeof (enum_name);
      status = RegEnumKeyEx(
			    network_connections_key,
			    i,
			    enum_name,
			    &len,
			    NULL,
			    NULL,
			    NULL,
			    NULL);
      if (status == ERROR_NO_MORE_ITEMS)
	break;
      else if (status != ERROR_SUCCESS)
	msg (M_FATAL, "Error enumerating registry subkeys of key: %s",
	     NETWORK_CONNECTIONS_KEY);

      openvpn_snprintf (connection_string, sizeof(connection_string),
			"%s\\%s\\Connection",
			NETWORK_CONNECTIONS_KEY, enum_name);

      status = RegOpenKeyEx(
			    HKEY_LOCAL_MACHINE,
			    connection_string,
			    0,
			    KEY_READ,
			    &connection_key);

      if (status != ERROR_SUCCESS)
	dmsg (D_REGISTRY, "Error opening registry key: %s", connection_string);
      else
	{
	  len = sizeof (name_data);
	  status = RegQueryValueEx(
				   connection_key,
				   name_string,
				   NULL,
				   &name_type,
				   name_data,
				   &len);

	  if (status != ERROR_SUCCESS || name_type != REG_SZ)
	    dmsg (D_REGISTRY, "Error opening registry key: %s\\%s\\%s",
		 NETWORK_CONNECTIONS_KEY, connection_string, name_string);
	  else
	    {
	      struct panel_reg *reg;

	      ALLOC_OBJ_CLEAR_GC (reg, struct panel_reg, gc);
	      reg->name = string_alloc (name_data, gc);
	      reg->guid = string_alloc (enum_name, gc);
		      
	      /* link into return list */
	      if (!first)
		first = reg;
	      if (last)
		last->next = reg;
	      last = reg;
	    }
	  RegCloseKey (connection_key);
	}
      ++i;
    }

  RegCloseKey (network_connections_key);

  return first;
}

/*
 * Check that two addresses are part of the same 255.255.255.252 subnet.
 */
void
verify_255_255_255_252 (in_addr_t local, in_addr_t remote)
{
  struct gc_arena gc = gc_new ();
  const unsigned int mask = 3;
  const char *err = NULL;

  if (local == remote)
    {
      err = "must be different";
      goto error;
    }
  if ((local & (~mask)) != (remote & (~mask)))
    {
      err = "must exist within the same 255.255.255.252 subnet.  This is a limitation of --dev tun when used with the TAP-WIN32 driver";
      goto error;
    }
  if ((local & mask) == 0
      || (local & mask) == 3
      || (remote & mask) == 0
      || (remote & mask) == 3)
    {
      err = "cannot use the first or last address within a given 255.255.255.252 subnet.  This is a limitation of --dev tun when used with the TAP-WIN32 driver";
      goto error;
    }

  gc_free (&gc);
  return;

 error:
  msg (M_FATAL, "There is a problem in your selection of --ifconfig endpoints [local=%s, remote=%s].  The local and remote VPN endpoints %s.  Try '" PACKAGE " --show-valid-subnets' option for more info.",
       print_in_addr_t (local, 0, &gc),
       print_in_addr_t (remote, 0, &gc),
       err);
  gc_free (&gc);
}

void show_valid_win32_tun_subnets (void)
{
  int i;
  int col = 0;

  printf ("On Windows, point-to-point IP support (i.e. --dev tun)\n");
  printf ("is emulated by the TAP-Win32 driver.  The major limitation\n");
  printf ("imposed by this approach is that the --ifconfig local and\n");
  printf ("remote endpoints must be part of the same 255.255.255.252\n");
  printf ("subnet.  The following list shows examples of endpoint\n");
  printf ("pairs which satisfy this requirement.  Only the final\n");
  printf ("component of the IP address pairs is at issue.\n\n");
  printf ("As an example, the following option would be correct:\n");
  printf ("    --ifconfig 10.7.0.5 10.7.0.6 (on host A)\n");
  printf ("    --ifconfig 10.7.0.6 10.7.0.5 (on host B)\n");
  printf ("because [5,6] is part of the below list.\n\n");

  for (i = 0; i < 256; i += 4)
    {
      printf("[%3d,%3d] ", i+1, i+2);
      if (++col > 4)
	{
	  col = 0;
	  printf ("\n");
	}
    }
  if (col)
    printf ("\n");
}

void
show_tap_win32_adapters (int msglev, int warnlev)
{
  struct gc_arena gc = gc_new ();

  bool warn_panel_null = false;
  bool warn_panel_dup = false;
  bool warn_tap_dup = false;

  int links;

  const struct tap_reg *tr;
  const struct tap_reg *tr1;
  const struct panel_reg *pr;

  const struct tap_reg *tap_reg = get_tap_reg (&gc);
  const struct panel_reg *panel_reg = get_panel_reg (&gc);

  msg (msglev, "Available TAP-WIN32 adapters [name, GUID]:");

  /* loop through each TAP-Win32 adapter registry entry */
  for (tr = tap_reg; tr != NULL; tr = tr->next)
    {
      links = 0;

      /* loop through each network connections entry in the control panel */
      for (pr = panel_reg; pr != NULL; pr = pr->next)
	{
	  if (!strcmp (tr->guid, pr->guid))
	    {
	      msg (msglev, "'%s' %s", pr->name, tr->guid);
	      ++links;
	    }
	}

      if (links > 1)
	{
	  warn_panel_dup = true;
	}
      else if (links == 0)
	{
	  /* a TAP adapter exists without a link from the network
	     connections control panel */
	  warn_panel_null = true;
	  msg (msglev, "[NULL] %s", tr->guid);
	}
    }

  /* check for TAP-Win32 adapter duplicated GUIDs */
  for (tr = tap_reg; tr != NULL; tr = tr->next)
    {