linux-stable.git/drivers/net/vxlan.c, branch v4.20

vxlan: changelink: Fix handling of default remotes

2018-12-19T05:18:26+00:00

Default remotes are stored as FDB entries with an Ethernet address of
00:00:00:00:00:00. When a request is made to change a remote address of
a VXLAN device, vxlan_changelink() first deletes the existing default
remote, and then creates a new FDB entry.

This works well as long as the list of default remotes matches exactly
the configuration of a VXLAN remote address. Thus when the VXLAN device
has a remote of X, there should be exactly one default remote FDB entry
X. If the VXLAN device has no remote address, there should be no such
entry.

Besides using "ip link set", it is possible to manipulate the list of
default remotes by using the "bridge fdb". It is therefore easy to break
the above condition. Under such circumstances, the __vxlan_fdb_delete()
call doesn't delete the FDB entry itself, but just one remote. The
following vxlan_fdb_create() then creates a new FDB entry, leading to a
situation where two entries exist for the address 00:00:00:00:00:00,
each with a different subset of default remotes.

An even more obvious breakage rooted in the same cause can be observed
when a remote address is configured for a VXLAN device that did not have
one before. In that case vxlan_changelink() doesn't remove any remote,
and just creates a new FDB entry for the new address:

$ ip link add name vx up type vxlan id 2000 dstport 4789
$ bridge fdb ap dev vx 00:00:00:00:00:00 dst 192.0.2.20 self permanent
$ bridge fdb ap dev vx 00:00:00:00:00:00 dst 192.0.2.30 self permanent
$ ip link set dev vx type vxlan remote 192.0.2.30
$ bridge fdb sh dev vx | grep 00:00:00:00:00:00
00:00:00:00:00:00 dst 192.0.2.30 self permanent <- new entry, 1 rdst
00:00:00:00:00:00 dst 192.0.2.20 self permanent <- orig. entry, 2 rdsts
00:00:00:00:00:00 dst 192.0.2.30 self permanent

To fix this, instead of calling vxlan_fdb_create() directly, defer to
vxlan_fdb_update(). That has logic to handle the duplicates properly.
Additionally, it also handles notifications, so drop that call from
changelink as well.

Fixes: 0241b836732f ("vxlan: fix default fdb entry netlink notify ordering during netdev create")
Signed-off-by: Petr Machata
Acked-by: Roopa Prabhu
Signed-off-by: David S. Miller

vxlan: Fix error path in __vxlan_dev_create()

2018-12-19T05:18:25+00:00

When a failure occurs in rtnl_configure_link(), the current code
calls unregister_netdevice() to roll back the earlier call to
register_netdevice(), and jumps to errout, which calls
vxlan_fdb_destroy().

However unregister_netdevice() calls transitively ndo_uninit, which is
vxlan_uninit(), and that already takes care of deleting the default FDB
entry by calling vxlan_fdb_delete_default(). Since the entry added
earlier in __vxlan_dev_create() is exactly the default entry, the
cleanup code in the errout block always leads to double free and thus a
panic.

Besides, since vxlan_fdb_delete_default() always destroys the FDB entry
with notification enabled, the deletion of the default entry is notified
even before the addition was notified.

Instead, move the unregister_netdevice() call after the manual destroy,
which solves both problems.

Fixes: 0241b836732f ("vxlan: fix default fdb entry netlink notify ordering during netdev create")
Signed-off-by: Petr Machata 
Signed-off-by: David S. Miller

vxlan: Unmark offloaded bit on replaced FDB entries

2018-12-19T05:18:25+00:00

When rdst of an offloaded FDB entry is replaced, it certainly isn't
offloaded anymore. Drivers are notified about such replacements, and can
re-mark the entry as offloaded again if they so wish. However until a
driver does so explicitly, assume a replaced FDB entry is not offloaded.

Note that replaces coming via vxlan_fdb_external_learn_add() are always
immediately followed by an explicit offload marking.

Fixes: 0efe11733356 ("vxlan: Support marking RDSTs as offloaded")
Signed-off-by: Petr Machata 
Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

2018-10-19T18:03:06+00:00

net/sched/cls_api.c has overlapping changes to a call to
nlmsg_parse(), one (from 'net') added rtm_tca_policy instead of NULL
to the 5th argument, and another (from 'net-next') added cb->extack
instead of NULL to the 6th argument.

net/ipv4/ipmr_base.c is a case of a bug fix in 'net' being done to
code which moved (to mr_table_dump)) in 'net-next'.  Thanks to David
Ahern for the heads up.

Signed-off-by: David S. Miller

geneve, vxlan: Don't set exceptions if skb->len < mtu

2018-10-18T04:51:13+00:00

We shouldn't abuse exceptions: if the destination MTU is already higher
than what we're transmitting, no exception should be created.

Fixes: 52a589d51f10 ("geneve: update skb dst pmtu on tx path")
Fixes: a93bf0ff4490 ("vxlan: update skb dst pmtu on tx path")
Signed-off-by: Stefano Brivio 
Reviewed-by: Sabrina Dubroca 
Signed-off-by: David S. Miller

geneve, vxlan: Don't check skb_dst() twice

2018-10-18T04:51:13+00:00

Commit f15ca723c1eb ("net: don't call update_pmtu unconditionally") avoids
that we try updating PMTU for a non-existent destination, but didn't clean
up cases where the check was already explicit. Drop those redundant checks.

Signed-off-by: Stefano Brivio 
Reviewed-by: Sabrina Dubroca 
Signed-off-by: David S. Miller

vxlan: Notify for each remote of a removed FDB entry

2018-10-18T00:45:08+00:00

When notifications are sent about FDB activity, and an FDB entry with
several remotes is removed, the notification is sent only for the first
destination. That makes it impossible to distinguish between the case
where only this first remote is removed, and the one where the FDB entry
is removed as a whole.

Therefore send one notification for each remote of a removed FDB entry.

Signed-off-by: Petr Machata 
Signed-off-by: Ido Schimmel 
Signed-off-by: David S. Miller

vxlan: Support marking RDSTs as offloaded

2018-10-18T00:45:08+00:00

Offloaded bridge FDB entries are marked with NTF_OFFLOADED. Implement a
similar mechanism for VXLAN, where a given remote destination can be
marked as offloaded.

To that end, introduce a new event, SWITCHDEV_VXLAN_FDB_OFFLOADED,
through which the marking is communicated to the vxlan driver. To
identify which RDST should be marked as offloaded, an
switchdev_notifier_vxlan_fdb_info is passed to the listeners. The
"offloaded" flag in that object determines whether the offloaded mark
should be set or cleared.

When sending offloaded FDB entries over netlink, mark them with
NTF_OFFLOADED.

Signed-off-by: Petr Machata 
Signed-off-by: Ido Schimmel 
Signed-off-by: David S. Miller

vxlan: Add vxlan_fdb_find_uc() for FDB querying

2018-10-18T00:45:08+00:00

A switchdev-capable driver that is aware of VXLAN may need to query
VXLAN FDB. In the particular case of mlxsw, this functionality is
limited to querying UC FDBs. Those being easier to deal with than the
general case of RDST chain traversal, introduce an interface to query
specifically UC FDBs: vxlan_fdb_find_uc().

Signed-off-by: Petr Machata 
Signed-off-by: Ido Schimmel 
Signed-off-by: David S. Miller

vxlan: Add switchdev notifications

2018-10-18T00:45:08+00:00

When offloading VXLAN devices, drivers need to know about events in
VXLAN FDB database. Since VXLAN models a bridge, it is natural to
distribute the VXLAN FDB notifications using the pre-existing switchdev
notification mechanism.

To that end, introduce two new notification types:
SWITCHDEV_VXLAN_FDB_ADD_TO_DEVICE and SWITCHDEV_VXLAN_FDB_DEL_TO_DEVICE.
Introduce a new function, vxlan_fdb_switchdev_call_notifiers() to send
the new notifier types, and a struct switchdev_notifier_vxlan_fdb_info
to communicate the details of the FDB entry under consideration.

Invoke the new function from vxlan_fdb_notify().

Signed-off-by: Petr Machata 
Signed-off-by: Ido Schimmel 
Signed-off-by: David S. Miller