NetworkManager/src/nm-netns.c
Thomas Haller 15b1304477 policy-routing: take ownership of externally configured rules
IP addresses, routes, TC and QDiscs are all tied to a certain interface.
So when NetworkManager manages an interface, it can be confident that
all related entires should be managed, deleted and modified by NetworkManager.

Routing policy rules are global. For that we have NMPRulesManager which
keeps track of whether NetworkManager owns a rule. This allows multiple
connection profiles to specify the same rule, and NMPRulesManager can
consolidate this information to know whether to add or remove the rule.

NMPRulesManager would also support to explicitly block a rule by
tracking it with negative priority. However that is still unused at
the moment. All that devices do is to add rules (track with positive
priority) and remove them (untrack) once the profile gets deactivated.

As rules are not exclusively owned by NetworkManager, NetworkManager
tries not to interfere with rules that it knows nothing about. That
means in particular, when NetworkManager starts it will "weakly track"
all rules that are present. "weakly track" is mostly interesting for two
cases:

  - when NMPRulesManager had the same rule explicitly tracked (added) by a
    device, then deactivating the device will leave the rule in place.

  - when NMPRulesManager had the same rule explicitly blocked (tracked
    with negative priority), then it would restore the rule when that
    block gets removed (as said, currently nobody actually does this).

Note that when restarting NetworkManager, then the device may stay and
the rules kept. However after restart, NetworkManager no longer knows
that it previously added this route, so it would weakly track it and
never remove them again.

That is a problem. Avoid that, by whenever explicitly tracking a rule we
also make sure to no longer weakly track it. Most likely this rule was
indeed previously managed by NetworkManager. If this was really a rule
added by externally, then the user really should choose distinct
rule priorities to avoid such conflicts altogether.
2019-07-16 10:16:07 +02:00

193 lines
5.5 KiB
C

/* NetworkManager -- Network link manager
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Copyright (C) 2017 Red Hat, Inc.
*/
#include "nm-default.h"
#include "nm-netns.h"
#include "nm-glib-aux/nm-dedup-multi.h"
#include "NetworkManagerUtils.h"
#include "nm-core-internal.h"
#include "platform/nm-platform.h"
#include "platform/nmp-netns.h"
#include "platform/nmp-rules-manager.h"
/*****************************************************************************/
NM_GOBJECT_PROPERTIES_DEFINE_BASE (
PROP_PLATFORM,
);
typedef struct {
NMPlatform *platform;
NMPNetns *platform_netns;
NMPRulesManager *rules_manager;
} NMNetnsPrivate;
struct _NMNetns {
GObject parent;
NMNetnsPrivate _priv;
};
struct _NMNetnsClass {
GObjectClass parent;
};
G_DEFINE_TYPE (NMNetns, nm_netns, G_TYPE_OBJECT);
#define NM_NETNS_GET_PRIVATE(self) _NM_GET_PRIVATE (self, NMNetns, NM_IS_NETNS)
/*****************************************************************************/
NM_DEFINE_SINGLETON_GETTER (NMNetns, nm_netns_get, NM_TYPE_NETNS);
/*****************************************************************************/
NMPNetns *
nm_netns_get_platform_netns (NMNetns *self)
{
return NM_NETNS_GET_PRIVATE (self)->platform_netns;
}
NMPlatform *
nm_netns_get_platform (NMNetns *self)
{
return NM_NETNS_GET_PRIVATE (self)->platform;
}
NMPRulesManager *
nm_netns_get_rules_manager (NMNetns *self)
{
return NM_NETNS_GET_PRIVATE (self)->rules_manager;
}
NMDedupMultiIndex *
nm_netns_get_multi_idx (NMNetns *self)
{
return nm_platform_get_multi_idx (NM_NETNS_GET_PRIVATE (self)->platform);
}
/*****************************************************************************/
static void
set_property (GObject *object, guint prop_id,
const GValue *value, GParamSpec *pspec)
{
NMNetns *self = NM_NETNS (object);
NMNetnsPrivate *priv = NM_NETNS_GET_PRIVATE (self);
switch (prop_id) {
case PROP_PLATFORM:
/* construct-only */
priv->platform = g_value_get_object (value) ?: NM_PLATFORM_GET;
if (!priv->platform)
g_return_if_reached ();
g_object_ref (priv->platform);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
/*****************************************************************************/
static void
nm_netns_init (NMNetns *self)
{
}
static void
constructed (GObject *object)
{
NMNetns *self = NM_NETNS (object);
NMNetnsPrivate *priv = NM_NETNS_GET_PRIVATE (self);
if (!priv->platform)
g_return_if_reached ();
priv->platform_netns = nm_platform_netns_get (priv->platform);
priv->rules_manager = nmp_rules_manager_new (priv->platform);
/* Weakly track the default rules with a dummy user-tag. These
* rules are always weekly tracked... */
nmp_rules_manager_track_default (priv->rules_manager,
AF_UNSPEC,
0,
nm_netns_parent_class /* static dummy user-tag */);
/* Also weakly track all existing rules. These were added before NetworkManager
* starts, so they are probably none of NetworkManager's business.
*
* However note that during service restart, devices may stay up and rules kept.
* That means, after restart such rules may have been added by a previous run
* of NetworkManager, we just don't know.
*
* For that reason, whenever we will touch such rules later one, we make them
* fully owned and no longer weekly tracked. See %NMP_RULES_MANAGER_EXTERN_WEAKLY_TRACKED_USER_TAG. */
nmp_rules_manager_track_from_platform (priv->rules_manager,
NULL,
AF_UNSPEC,
0,
NMP_RULES_MANAGER_EXTERN_WEAKLY_TRACKED_USER_TAG);
G_OBJECT_CLASS (nm_netns_parent_class)->constructed (object);
}
NMNetns *
nm_netns_new (NMPlatform *platform)
{
return g_object_new (NM_TYPE_NETNS,
NM_NETNS_PLATFORM, platform,
NULL);
}
static void
dispose (GObject *object)
{
NMNetns *self = NM_NETNS (object);
NMNetnsPrivate *priv = NM_NETNS_GET_PRIVATE (self);
g_clear_object (&priv->platform);
nm_clear_pointer (&priv->rules_manager, nmp_rules_manager_unref);
G_OBJECT_CLASS (nm_netns_parent_class)->dispose (object);
}
static void
nm_netns_class_init (NMNetnsClass *klass)
{
GObjectClass *object_class = G_OBJECT_CLASS (klass);
object_class->constructed = constructed;
object_class->set_property = set_property;
object_class->dispose = dispose;
obj_properties[PROP_PLATFORM] =
g_param_spec_object (NM_NETNS_PLATFORM, "", "",
NM_TYPE_PLATFORM,
G_PARAM_WRITABLE |
G_PARAM_CONSTRUCT_ONLY |
G_PARAM_STATIC_STRINGS);
g_object_class_install_properties (object_class, _PROPERTY_ENUMS_LAST, obj_properties);
}