tun.c

tun虚拟网卡设备源码

      for (tr1 = tap_reg; tr1 != NULL; tr1 = tr1->next)
	{
	  if (tr != tr1 && !strcmp (tr->guid, tr1->guid))
	    warn_tap_dup = true;
	}
    }

  /* warn on registry inconsistencies */
  if (warn_tap_dup)
    msg (warnlev, "WARNING: Some TAP-Win32 adapters have duplicate GUIDs");

  if (warn_panel_dup)
    msg (warnlev, "WARNING: Some TAP-Win32 adapters have duplicate links from the Network Connections control panel");

  if (warn_panel_null)
    msg (warnlev, "WARNING: Some TAP-Win32 adapters have no link from the Network Connections control panel");

  gc_free (&gc);
}

/*
 * Confirm that GUID is a TAP-Win32 adapter.
 */
static bool
is_tap_win32 (const char *guid, const struct tap_reg *tap_reg)
{
  const struct tap_reg *tr;

  for (tr = tap_reg; tr != NULL; tr = tr->next)
    {
      if (guid && !strcmp (tr->guid, guid))
	return true;
    }

  return false;
}

static const char *
guid_to_name (const char *guid, const struct panel_reg *panel_reg)
{
  const struct panel_reg *pr;

  for (pr = panel_reg; pr != NULL; pr = pr->next)
    {
      if (guid && !strcmp (pr->guid, guid))
	return pr->name;
    }

  return NULL;
}

static const char *
name_to_guid (const char *name, const struct tap_reg *tap_reg, const struct panel_reg *panel_reg)
{
  const struct panel_reg *pr;

  for (pr = panel_reg; pr != NULL; pr = pr->next)
    {
      if (name && !strcmp (pr->name, name) && is_tap_win32 (pr->guid, tap_reg))
	return pr->guid;
    }

  return NULL;
}

static void
at_least_one_tap_win32 (const struct tap_reg *tap_reg)
{
  if (!tap_reg)
    msg (M_FATAL, "There are no TAP-Win32 adapters on this system.  You should be able to create a TAP-Win32 adapter by going to Start -> All Programs -> " PACKAGE_NAME " -> Add a new TAP-Win32 virtual ethernet adapter.");
}

/*
 * Get an adapter GUID and optional actual_name from the 
 * registry for the TAP device # = device_number.
 */
static const char *
get_unspecified_device_guid (const int device_number,
		             char *actual_name,
		             int actual_name_size,
			     const struct tap_reg *tap_reg_src,
			     const struct panel_reg *panel_reg_src,
		             struct gc_arena *gc)
{
  const struct tap_reg *tap_reg = tap_reg_src;
  struct buffer ret = clear_buf ();
  struct buffer actual = clear_buf ();
  int i;

  ASSERT (device_number >= 0);

  /* Make sure we have at least one TAP adapter */
  if (!tap_reg)
    return NULL;

  /* The actual_name output buffer may be NULL */
  if (actual_name)
    {
      ASSERT (actual_name_size > 0);
      buf_set_write (&actual, actual_name, actual_name_size);
    }

  /* Move on to specified device number */
  for (i = 0; i < device_number; i++)
    {
      tap_reg = tap_reg->next;
      if (!tap_reg)
	return NULL;
    }

  /* Save Network Panel name (if exists) in actual_name */
  if (actual_name)
    {
      const char *act = guid_to_name (tap_reg->guid, panel_reg_src);
      if (act)
	buf_printf (&actual, "%s", act);
      else
	buf_printf (&actual, "NULL");
    }

  /* Save GUID for return value */
  ret = alloc_buf_gc (256, gc);
  buf_printf (&ret, "%s", tap_reg->guid);
  return BSTR (&ret);
}

/*
 * Lookup a --dev-node adapter name in the registry
 * returning the GUID and optional actual_name.
 */
static const char *
get_device_guid (const char *name,
		 char *actual_name,
		 int actual_name_size,
		 const struct tap_reg *tap_reg,
		 const struct panel_reg *panel_reg,
		 struct gc_arena *gc)
{
  struct buffer ret = alloc_buf_gc (256, gc);
  struct buffer actual = clear_buf ();

  /* Make sure we have at least one TAP adapter */
  if (!tap_reg)
    return NULL;

  /* The actual_name output buffer may be NULL */
  if (actual_name)
    {
      ASSERT (actual_name_size > 0);
      buf_set_write (&actual, actual_name, actual_name_size);
    }

  /* Check if GUID was explicitly specified as --dev-node parameter */
  if (is_tap_win32 (name, tap_reg))
    {
      const char *act = guid_to_name (name, panel_reg);
      buf_printf (&ret, "%s", name);
      if (act)
	buf_printf (&actual, "%s", act);
      else
	buf_printf (&actual, "NULL");
      return BSTR (&ret);
    }

  /* Lookup TAP adapter in network connections list */
  {
    const char *guid = name_to_guid (name, tap_reg, panel_reg);
    if (guid)
      {
	buf_printf (&actual, "%s", name);
	buf_printf (&ret, "%s", guid);
	return BSTR (&ret);
      }
  }

  return NULL;
}

/*
 * Return a TAP name for netsh commands.
 */
const char *
get_netsh_id (const char *dev_node, struct gc_arena *gc)
{
  const struct tap_reg *tap_reg = get_tap_reg (gc);
  const struct panel_reg *panel_reg = get_panel_reg (gc);
  struct buffer actual = alloc_buf_gc (256, gc);
  const char *guid;

  at_least_one_tap_win32 (tap_reg);

  if (dev_node)
    {
      guid = get_device_guid (dev_node, BPTR (&actual), BCAP (&actual), tap_reg, panel_reg, gc);
    }
  else
    {
      guid = get_unspecified_device_guid (0, BPTR (&actual), BCAP (&actual), tap_reg, panel_reg, gc);

      if (get_unspecified_device_guid (1, NULL, 0, tap_reg, panel_reg, gc)) /* ambiguous if more than one TAP-Win32 adapter */
	guid = NULL;
    }

  if (!guid)
    return "NULL";         /* not found */
  else if (strcmp (BPTR (&actual), "NULL"))
    return BPTR (&actual); /* control panel name */
  else
    return guid;           /* no control panel name, return GUID instead */
}

/*
 * Get adapter info list
 */
const IP_ADAPTER_INFO *
get_adapter_info_list (struct gc_arena *gc)
{
  ULONG size = 0;
  IP_ADAPTER_INFO *pi = NULL;
  DWORD status;

  if ((status = GetAdaptersInfo (NULL, &size)) != ERROR_BUFFER_OVERFLOW)
    {
      msg (M_INFO, "GetAdaptersInfo #1 failed (status=%u) : %s",
	   (unsigned int)status,
	   strerror_win32 (status, gc));
    }
  else
    {
      pi = (PIP_ADAPTER_INFO) gc_malloc (size, false, gc);
      if ((status = GetAdaptersInfo (pi, &size)) == NO_ERROR)
	return pi;
      else
	{
	  msg (M_INFO, "GetAdaptersInfo #2 failed (status=%u) : %s",
	       (unsigned int)status,
	       strerror_win32 (status, gc));
	}
    }
  return pi;
}

static const IP_INTERFACE_INFO *
get_interface_info_list (struct gc_arena *gc)
{
  ULONG size = 0;
  IP_INTERFACE_INFO *ii = NULL;
  DWORD status;

  if ((status = GetInterfaceInfo (NULL, &size)) != ERROR_INSUFFICIENT_BUFFER)
    {
      msg (M_INFO, "GetInterfaceInfo #1 failed (status=%u) : %s",
	   (unsigned int)status,
	   strerror_win32 (status, gc));
    }
  else
    {
      ii = (PIP_INTERFACE_INFO) gc_malloc (size, false, gc);
      if ((status = GetInterfaceInfo (ii, &size)) == NO_ERROR)
	return ii;
      else
	{
	  msg (M_INFO, "GetInterfaceInfo #2 failed (status=%u) : %s",
	       (unsigned int)status,
	       strerror_win32 (status, gc));
	}
    }
  return ii;
}

static const IP_ADAPTER_INDEX_MAP *
get_interface_info (DWORD index, struct gc_arena *gc)
{
  const IP_INTERFACE_INFO *list = get_interface_info_list (gc);
  if (list)
    {
      int i;
      for (i = 0; i < list->NumAdapters; ++i)
	{
	  const IP_ADAPTER_INDEX_MAP *inter = &list->Adapter[i];
	  if (index == inter->Index)
	    return inter;
	}
    }
  return NULL;
}

/*
 * Given an adapter index, return a pointer to the
 * IP_ADAPTER_INFO structure for that adapter.
 */

static const IP_ADAPTER_INFO *
get_adapter (const IP_ADAPTER_INFO *ai, DWORD index)
{
  if (ai && index != (DWORD)~0)
    {
      const IP_ADAPTER_INFO *a;

      /* find index in the linked list */
      for (a = ai; a != NULL; a = a->Next)
	{
	  if (a->Index == index)
	    return a;
	}
    }
  return NULL;
}

static const IP_ADAPTER_INFO *
get_adapter_info (DWORD index, struct gc_arena *gc)
{
  return get_adapter (get_adapter_info_list (gc), index);
}

static int
get_adapter_n_ip_netmask (const IP_ADAPTER_INFO *ai)
{
  if (ai)
    {
      int n = 0;
      const IP_ADDR_STRING *ip = &ai->IpAddressList;

      while (ip)
	{
	  ++n;
	  ip = ip->Next;
	}
      return n;
    }
  else
    return 0;
}

static bool
get_adapter_ip_netmask (const IP_ADAPTER_INFO *ai, const int n, in_addr_t *ip, in_addr_t *netmask)
{
  bool ret = false;
  *ip = 0;
  *netmask = 0;

  if (ai)
    {
      const IP_ADDR_STRING *iplist = &ai->IpAddressList;
      int i = 0;

      while (iplist)
	{
	  if (i == n)
	    break;
	  ++i;
	  iplist = iplist->Next;
	}

      if (iplist)
	{
	  const unsigned int getaddr_flags = GETADDR_HOST_ORDER;
	  const char *ip_str = iplist->IpAddress.String;
	  const char *netmask_str = iplist->IpMask.String;
	  bool succeed1 = false;
	  bool succeed2 = false;

	  if (ip_str && netmask_str && strlen (ip_str) && strlen (netmask_str))
	    {
	      *ip = getaddr (getaddr_flags, ip_str, 0, &succeed1, NULL);
	      *netmask = getaddr (getaddr_flags, netmask_str, 0, &succeed2, NULL);
	      ret = (succeed1 == true && succeed2 == true);
	    }
	}
    }

  return ret;
}

const IP_ADAPTER_INFO *
get_tun_adapter (const struct tuntap *tt, const IP_ADAPTER_INFO *list)
{
  if (list && tt)
    return get_adapter (list, tt->adapter_index);
  else
    return NULL;
}

bool
is_adapter_up (const struct tuntap *tt, const IP_ADAPTER_INFO *list)
{
  int i;
  bool ret = false;

  const IP_ADAPTER_INFO *ai = get_tun_adapter (tt, list);

  if (ai)
    {
      const int n = get_adapter_n_ip_netmask (ai);

      /* loop once for every IP/netmask assigned to adapter */
      for (i = 0; i < n; ++i)
	{
	  in_addr_t ip, netmask;
	  if (get_adapter_ip_netmask (ai, i, &ip, &netmask))
	    {
	      if (tt->local && tt->adapter_netmask)
		{
		  /* wait for our --ifconfig parms to match the actual adapter parms */
		  if (tt->local == ip && tt->adapter_netmask == netmask)
		    ret = true;
		}
	      else
		{
		  /* --ifconfig was not defined, maybe using a real DHCP server */
		  if (ip && netmask)
		    ret = true;
		}
	    }
	}
    }
  else
    ret = true; /* this can occur when TAP adapter is bridged */

  return ret;
}

bool
is_ip_in_adapter_subnet (const IP_ADAPTER_INFO *ai, const in_addr_t ip, in_addr_t *highest_netmask)
{
  int i;
  bool ret = false;

  if (highest_netmask)
    *highest_netmask = 0;

  if (ai)
    {
      const int n = get_adapter_n_ip_netmask (ai);
      for (i = 0; i < n; ++i)
	{
	  in_addr_t adapter_ip, adapter_netmask;
	  if (get_adapter_ip_netmask (ai, i, &adapter_ip, &adapter_netmask))
	    {
	      if (adapter_ip && adapter_netmask && (ip & adapter_netmask) == (adapter_ip & adapter_netmask))
		{
		  if (highest_netmask && adapter_netmask > *highest_netmask)
		    *highest_netmask = adapter_netmask;
		  ret = true;
		}
	    }
	}
    }
  return ret;
}

DWORD
adapter_index_of_ip (const IP_ADAPTER_INFO *list, const in_addr_t ip, int *count)
{
  struct gc_arena gc = gc_new ();
  DWORD ret = ~0;
  in_addr_t highest_netmask = 0;
  bool first = true;

  if (count)
    *count = 0;

  while (list)
    {
      in_addr_t hn;

      if (is_ip_in_adapter_subnet (list, ip, &hn))
	{
	  if (first || hn > highest_netmask)
	    {
	      highest_netmask = hn;
	      if (count)
		*count = 1;
	      ret = list->Index;
	      first = false;
	    }
	  else if (hn == highest_netmask)
	    {
	      if (count)
		++*count;
	    }
	}
      list = list->Next;
    }

  dmsg (D_ROUTE_DEBUG, "DEBUG: IP Locate: ip=%s nm=%s index=%d count=%d",
       print_in_addr_t (ip, 0, &gc),
       print_in_addr_t (highest_netmask, 0, &gc),
       (int)ret,
       count ? *count : -1);

  if (ret == ~0 && count)
    *count = 0;

  gc_free (&gc);
  return ret;
}

/*
 * Given an adapter index, return true if the adapter
 * is DHCP disabled.
 */
static bool
dhcp_disabled (DWORD index)
{
  struct gc_arena gc = gc_new ();
  const IP_ADAPTER_INFO *ai = get_adapter_info (index, &gc);
  bool ret = false;

  if (ai && !ai->DhcpEnabled)
    ret = true;

  gc_free (&gc);
  return ret;
}

/*
 * Delete all temporary address/netmask pairs which were added
 * to adapter (given by index) by previous calls to AddIPAddress.
 */
static void
delete_temp_addresses (DWORD index)
{
  struct gc_arena gc = gc_new ();
  const IP_ADAPTER_INFO *a = get_adapter_info (index, &gc);

  if (a)
    {
      const IP_ADDR_STRING *ip = &a->IpAddressList;
      while (ip)
	{
	  DWORD status;
	  const DWORD c