Files
NetworkManager/libnm-core/nm-setting-tun.c
Thomas Haller 39ab38a04d core/platform: add support for TUN/TAP netlink support and various cleanup
Kernel recently got support for exposing TUN/TAP information on netlink
[1], [2], [3]. Add support for it to the platform cache.

The advantage of using netlink is that querying sysctl bypasses the
order of events of the netlink socket. It is out of sync and racy. For
example, platform cache might still think that a tun device exists, but
a subsequent lookup at sysfs might fail because the device was deleted
in the meantime. Another point is, that we don't get change
notifications via sysctl and that it requires various extra syscalls
to read the device information. If the tun information is present on
netlink, put it into the cache. This bypasses checking sysctl while
we keep looking at sysctl for backward compatibility until we require
support from kernel.

Notes:

- we had two link types NM_LINK_TYPE_TAP and NM_LINK_TYPE_TUN. This
  deviates from the model of how kernel treats TUN/TAP devices, which
  makes it more complicated. The link type of a NMPlatformLink instance
  should match what kernel thinks about the device. Point in case,
  when parsing RTM_NETLINK messages, we very early need to determine
  the link type (_linktype_get_type()). However, to determine the
  type of a TUN/TAP at that point, we need to look into nested
  netlink attributes which in turn depend on the type (IFLA_INFO_KIND
  and IFLA_INFO_DATA), or even worse, we would need to look into
  sysctl for older kernel vesions. Now, the TUN/TAP type is a property
  of the link type NM_LINK_TYPE_TUN, instead of determining two
  different link types.

- various parts of the API (both kernel's sysctl vs. netlink) and
  NMDeviceTun vs. NMSettingTun disagree whether the PI is positive
  (NM_SETTING_TUN_PI, IFLA_TUN_PI, NMPlatformLnkTun.pi) or inverted
  (NM_DEVICE_TUN_NO_PI, IFF_NO_PI). There is no consistent way,
  but prefer the positive form for internal API at NMPlatformLnkTun.pi.

- previously NMDeviceTun.mode could not change after initializing
  the object. Allow for that to happen, because forcing some properties
  that are reported by kernel to not change is wrong, in case they
  might change. Of course, in practice kernel doesn't allow the device
  to ever change its type, but the type property of the NMDeviceTun
  should not make that assumption, because, if it actually changes, what
  would it mean?

- note that as of now, new netlink API is not yet merged to mainline Linus
  tree. Shortcut _parse_lnk_tun() to not accidentally use unstable API
  for now.

[1] https://bugzilla.redhat.com/show_bug.cgi?id=1277457
[2] https://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git/commit/?id=1ec010e705934c8acbe7dbf31afc81e60e3d828b
[3] https://git.kernel.org/pub/scm/network/iproute2/iproute2-next.git/commit/?id=118eda77d6602616bc523a17ee45171e879d1818

https://bugzilla.redhat.com/show_bug.cgi?id=1547213
https://github.com/NetworkManager/NetworkManager/pull/77
2018-03-20 11:59:52 +01:00

410 lines
11 KiB
C

/* -*- Mode: C; tab-width: 4; indent-tabs-mode: t; c-basic-offset: 4 -*- */
/*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301 USA.
*
* Copyright 2015 Red Hat, Inc.
*/
#include "nm-default.h"
#include <stdlib.h>
#include <string.h>
#include "nm-setting-tun.h"
#include "nm-utils.h"
#include "nm-setting-connection.h"
#include "nm-setting-private.h"
#include "nm-connection-private.h"
/**
* SECTION:nm-setting-tun
* @short_description: Describes connection properties for TUN/TAP interfaces
*
* The #NMSettingTun object is a #NMSetting subclass that describes properties
* necessary for connection to TUN/TAP interfaces.
**/
G_DEFINE_TYPE_WITH_CODE (NMSettingTun, nm_setting_tun, NM_TYPE_SETTING,
_nm_register_setting (TUN, NM_SETTING_PRIORITY_HW_BASE))
NM_SETTING_REGISTER_TYPE (NM_TYPE_SETTING_TUN)
#define NM_SETTING_TUN_GET_PRIVATE(o) (G_TYPE_INSTANCE_GET_PRIVATE ((o), NM_TYPE_SETTING_TUN, NMSettingTunPrivate))
typedef struct {
NMSettingTunMode mode;
char *owner;
char *group;
gboolean pi;
gboolean vnet_hdr;
gboolean multi_queue;
} NMSettingTunPrivate;
enum {
PROP_0,
PROP_MODE,
PROP_OWNER,
PROP_GROUP,
PROP_PI,
PROP_VNET_HDR,
PROP_MULTI_QUEUE,
LAST_PROP
};
/**
* nm_setting_tun_new:
*
* Creates a new #NMSettingTun object with default values.
*
* Returns: (transfer full): the new empty #NMSettingTun object
*
* Since: 1.2
**/
NMSetting *
nm_setting_tun_new (void)
{
return (NMSetting *) g_object_new (NM_TYPE_SETTING_TUN, NULL);
}
/**
* nm_setting_tun_get_mode:
* @setting: the #NMSettingTun
*
* Returns: the #NMSettingTun:mode property of the setting
*
* Since: 1.2
**/
NMSettingTunMode
nm_setting_tun_get_mode (NMSettingTun *setting)
{
g_return_val_if_fail (NM_IS_SETTING_TUN (setting), NM_SETTING_TUN_MODE_TUN);
return NM_SETTING_TUN_GET_PRIVATE (setting)->mode;
}
/**
* nm_setting_tun_get_owner:
* @setting: the #NMSettingTun
*
* Returns: the #NMSettingTun:owner property of the setting
*
* Since: 1.2
**/
const char *
nm_setting_tun_get_owner (NMSettingTun *setting)
{
g_return_val_if_fail (NM_IS_SETTING_TUN (setting), NULL);
return NM_SETTING_TUN_GET_PRIVATE (setting)->owner;
}
/**
* nm_setting_tun_get_group:
* @setting: the #NMSettingTun
*
* Returns: the #NMSettingTun:group property of the setting
*
* Since: 1.2
**/
const char *
nm_setting_tun_get_group (NMSettingTun *setting)
{
g_return_val_if_fail (NM_IS_SETTING_TUN (setting), NULL);
return NM_SETTING_TUN_GET_PRIVATE (setting)->group;
}
/**
* nm_setting_tun_get_pi:
* @setting: the #NMSettingTun
*
* Returns: the #NMSettingTun:pi property of the setting
*
* Since: 1.2
**/
gboolean
nm_setting_tun_get_pi (NMSettingTun *setting)
{
g_return_val_if_fail (NM_IS_SETTING_TUN (setting), FALSE);
return NM_SETTING_TUN_GET_PRIVATE (setting)->pi;
}
/**
* nm_setting_tun_get_vnet_hdr:
* @setting: the #NMSettingTun
*
* Returns: the #NMSettingTun:vnet_hdr property of the setting
*
* Since: 1.2
**/
gboolean
nm_setting_tun_get_vnet_hdr (NMSettingTun *setting)
{
g_return_val_if_fail (NM_IS_SETTING_TUN (setting), FALSE);
return NM_SETTING_TUN_GET_PRIVATE (setting)->vnet_hdr;
}
/**
* nm_setting_tun_get_multi_queue:
* @setting: the #NMSettingTun
*
* Returns: the #NMSettingTun:multi-queue property of the setting
*
* Since: 1.2
**/
gboolean
nm_setting_tun_get_multi_queue (NMSettingTun *setting)
{
g_return_val_if_fail (NM_IS_SETTING_TUN (setting), FALSE);
return NM_SETTING_TUN_GET_PRIVATE (setting)->multi_queue;
}
static void
nm_setting_tun_init (NMSettingTun *setting)
{
}
static gboolean
verify (NMSetting *setting, NMConnection *connection, GError **error)
{
NMSettingTunPrivate *priv = NM_SETTING_TUN_GET_PRIVATE (setting);
if (!NM_IN_SET (priv->mode, NM_SETTING_TUN_MODE_TUN,
NM_SETTING_TUN_MODE_TAP)) {
g_set_error (error,
NM_CONNECTION_ERROR,
NM_CONNECTION_ERROR_INVALID_PROPERTY,
_("'%u': invalid mode"), (unsigned) priv->mode);
g_prefix_error (error, "%s.%s: ", NM_SETTING_TUN_SETTING_NAME, NM_SETTING_TUN_MODE);
return FALSE;
}
if (priv->owner) {
if (_nm_utils_ascii_str_to_int64 (priv->owner, 10, 0, G_MAXINT32, -1) == -1) {
g_set_error (error,
NM_CONNECTION_ERROR,
NM_CONNECTION_ERROR_INVALID_PROPERTY,
_("'%s': invalid user ID"), priv->owner);
g_prefix_error (error, "%s.%s: ", NM_SETTING_TUN_SETTING_NAME, NM_SETTING_TUN_OWNER);
return FALSE;
}
}
if (priv->group) {
if (_nm_utils_ascii_str_to_int64 (priv->group, 10, 0, G_MAXINT32, -1) == -1) {
g_set_error (error,
NM_CONNECTION_ERROR,
NM_CONNECTION_ERROR_INVALID_PROPERTY,
_("'%s': invalid group ID"), priv->group);
g_prefix_error (error, "%s.%s: ", NM_SETTING_TUN_SETTING_NAME, NM_SETTING_TUN_GROUP);
return FALSE;
}
}
return TRUE;
}
static void
set_property (GObject *object, guint prop_id,
const GValue *value, GParamSpec *pspec)
{
NMSettingTun *setting = NM_SETTING_TUN (object);
NMSettingTunPrivate *priv = NM_SETTING_TUN_GET_PRIVATE (setting);
switch (prop_id) {
case PROP_MODE:
priv->mode = g_value_get_uint (value);
break;
case PROP_OWNER:
g_free (priv->owner);
priv->owner = g_value_dup_string (value);
break;
case PROP_GROUP:
g_free (priv->group);
priv->group = g_value_dup_string (value);
break;
case PROP_PI:
priv->pi = g_value_get_boolean (value);
break;
case PROP_VNET_HDR:
priv->vnet_hdr = g_value_get_boolean (value);
break;
case PROP_MULTI_QUEUE:
priv->multi_queue = g_value_get_boolean (value);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static void
get_property (GObject *object, guint prop_id,
GValue *value, GParamSpec *pspec)
{
NMSettingTun *setting = NM_SETTING_TUN (object);
NMSettingTunPrivate *priv = NM_SETTING_TUN_GET_PRIVATE (setting);
switch (prop_id) {
case PROP_MODE:
g_value_set_uint (value, priv->mode);
break;
case PROP_OWNER:
g_value_set_string (value, priv->owner);
break;
case PROP_GROUP:
g_value_set_string (value, priv->group);
break;
case PROP_PI:
g_value_set_boolean (value, priv->pi);
break;
case PROP_VNET_HDR:
g_value_set_boolean (value, priv->vnet_hdr);
break;
case PROP_MULTI_QUEUE:
g_value_set_boolean (value, priv->multi_queue);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static void
finalize (GObject *object)
{
NMSettingTun *setting = NM_SETTING_TUN (object);
NMSettingTunPrivate *priv = NM_SETTING_TUN_GET_PRIVATE (setting);
g_free (priv->owner);
g_free (priv->group);
G_OBJECT_CLASS (nm_setting_tun_parent_class)->finalize (object);
}
static void
nm_setting_tun_class_init (NMSettingTunClass *setting_class)
{
GObjectClass *object_class = G_OBJECT_CLASS (setting_class);
NMSettingClass *parent_class = NM_SETTING_CLASS (setting_class);
g_type_class_add_private (setting_class, sizeof (NMSettingTunPrivate));
/* virtual methods */
object_class->set_property = set_property;
object_class->get_property = get_property;
object_class->finalize = finalize;
parent_class->verify = verify;
/* Properties */
/**
* NMSettingTun:mode:
*
* The operating mode of the virtual device. Allowed values are
* %NM_SETTING_TUN_MODE_TUN to create a layer 3 device and
* %NM_SETTING_TUN_MODE_TAP to create an Ethernet-like layer 2
* one.
*
* Since: 1.2
*/
g_object_class_install_property
(object_class, PROP_MODE,
g_param_spec_uint (NM_SETTING_TUN_MODE, "", "",
0, G_MAXUINT, NM_SETTING_TUN_MODE_TUN,
G_PARAM_READWRITE |
G_PARAM_CONSTRUCT |
NM_SETTING_PARAM_INFERRABLE |
G_PARAM_STATIC_STRINGS));
/**
* NMSettingTun:owner:
*
* The user ID which will own the device. If set to %NULL everyone
* will be able to use the device.
*
* Since: 1.2
*/
g_object_class_install_property
(object_class, PROP_OWNER,
g_param_spec_string (NM_SETTING_TUN_OWNER, "", "",
NULL,
G_PARAM_READWRITE |
NM_SETTING_PARAM_INFERRABLE |
G_PARAM_STATIC_STRINGS));
/**
* NMSettingTun:group:
*
* The group ID which will own the device. If set to %NULL everyone
* will be able to use the device.
*
* Since: 1.2
*/
g_object_class_install_property
(object_class, PROP_GROUP,
g_param_spec_string (NM_SETTING_TUN_GROUP, "", "",
NULL,
G_PARAM_READWRITE |
NM_SETTING_PARAM_INFERRABLE |
G_PARAM_STATIC_STRINGS));
/**
* NMSettingTun:pi:
*
* If %TRUE the interface will prepend a 4 byte header describing the
* physical interface to the packets.
*
* Since: 1.2
*/
g_object_class_install_property
(object_class, PROP_PI,
g_param_spec_boolean (NM_SETTING_TUN_PI, "", "",
FALSE,
G_PARAM_READWRITE |
NM_SETTING_PARAM_INFERRABLE |
G_PARAM_STATIC_STRINGS));
/**
* NMSettingTun:vnet-hdr:
*
* If %TRUE the IFF_VNET_HDR the tunnel packets will include a virtio
* network header.
*
* Since: 1.2
*/
g_object_class_install_property
(object_class, PROP_VNET_HDR,
g_param_spec_boolean (NM_SETTING_TUN_VNET_HDR, "", "",
FALSE,
G_PARAM_READWRITE |
NM_SETTING_PARAM_INFERRABLE |
G_PARAM_STATIC_STRINGS));
/**
* NMSettingTun:multi-queue:
*
* If the property is set to %TRUE, the interface will support
* multiple file descriptors (queues) to parallelize packet
* sending or receiving. Otherwise, the interface will only
* support a single queue.
*
* Since: 1.2
*/
g_object_class_install_property
(object_class, PROP_MULTI_QUEUE,
g_param_spec_boolean (NM_SETTING_TUN_MULTI_QUEUE, "", "",
FALSE,
G_PARAM_READWRITE |
NM_SETTING_PARAM_INFERRABLE |
G_PARAM_STATIC_STRINGS));
}