linux.git/net/core/rtnetlink.c, branch v6.4-rc2

bridge: Allow setting per-{Port, VLAN} neighbor suppression state

2023-04-21T07:25:50+00:00

Add a new bridge port attribute that allows user space to enable
per-{Port, VLAN} neighbor suppression. Example:

 # bridge -d -j -p link show dev swp1 | jq '.[]["neigh_vlan_suppress"]'
 false
 # bridge link set dev swp1 neigh_vlan_suppress on
 # bridge -d -j -p link show dev swp1 | jq '.[]["neigh_vlan_suppress"]'
 true
 # bridge link set dev swp1 neigh_vlan_suppress off
 # bridge -d -j -p link show dev swp1 | jq '.[]["neigh_vlan_suppress"]'
 false

Signed-off-by: Ido Schimmel 
Acked-by: Nikolay Aleksandrov 
Signed-off-by: David S. Miller

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

2023-04-13T23:04:28+00:00

Conflicts:

tools/testing/selftests/net/config
  62199e3f1658 ("selftests: net: Add VXLAN MDB test")
  3a0385be133e ("selftests: add the missing CONFIG_IP_SCTP in net config")

Signed-off-by: Jakub Kicinski

rtnetlink: Restore RTM_NEW/DELLINK notification behavior

2023-04-13T03:47:58+00:00

The commits referenced below allows userspace to use the NLM_F_ECHO flag
for RTM_NEW/DELLINK operations to receive unicast notifications for the
affected link. Prior to these changes, applications may have relied on
multicast notifications to learn the same information without specifying
the NLM_F_ECHO flag.

For such applications, the mentioned commits changed the behavior for
requests not using NLM_F_ECHO. Multicast notifications are still received,
but now use the portid of the requester and the sequence number of the
request instead of zero values used previously. For the application, this
message may be unexpected and likely handled as a response to the
NLM_F_ACKed request, especially if it uses the same socket to handle
requests and notifications.

To fix existing applications relying on the old notification behavior,
set the portid and sequence number in the notification only if the
request included the NLM_F_ECHO flag. This restores the old behavior
for applications not using it, but allows unicasted notifications for
others.

Fixes: f3a63cce1b4f ("rtnetlink: Honour NLM_F_ECHO flag in rtnl_delete_link")
Fixes: d88e136cab37 ("rtnetlink: Honour NLM_F_ECHO flag in rtnl_newlink_create")
Signed-off-by: Martin Willi 
Acked-by: Guillaume Nault 
Acked-by: Hangbin Liu 
Link: https://lore.kernel.org/r/20230411074319.24133-1-martin@strongswan.org
Signed-off-by: Jakub Kicinski

net: dst: Switch to rcuref_t reference counting

2023-03-29T01:52:28+00:00

Under high contention dst_entry::__refcnt becomes a significant bottleneck.

atomic_inc_not_zero() is implemented with a cmpxchg() loop, which goes into
high retry rates on contention.

Switch the reference count to rcuref_t which results in a significant
performance gain. Rename the reference count member to __rcuref to reflect
the change.

The gain depends on the micro-architecture and the number of concurrent
operations and has been measured in the range of +25% to +130% with a
localhost memtier/memcached benchmark which amplifies the problem
massively.

Running the memtier/memcached benchmark over a real (1Gb) network
connection the conversion on top of the false sharing fix for struct
dst_entry::__refcnt results in a total gain in the 2%-5% range over the
upstream baseline.

Reported-by: Wangyang Guo 
Reported-by: Arjan Van De Ven 
Signed-off-by: Thomas Gleixner 
Link: https://lore.kernel.org/r/20230307125538.989175656@linutronix.de
Link: https://lore.kernel.org/r/20230323102800.215027837@linutronix.de
Signed-off-by: Jakub Kicinski

rtnetlink: bridge: mcast: Relax group address validation in common code

2023-03-17T08:05:49+00:00

In the upcoming VXLAN MDB implementation, the 0.0.0.0 and :: MDB entries
will act as catchall entries for unregistered IP multicast traffic in a
similar fashion to the 00:00:00:00:00:00 VXLAN FDB entry that is used to
transmit BUM traffic.

In deployments where inter-subnet multicast forwarding is used, not all
the VTEPs in a tenant domain are members in all the broadcast domains.
It is therefore advantageous to transmit BULL (broadcast, unknown
unicast and link-local multicast) and unregistered IP multicast traffic
on different tunnels. If the same tunnel was used, a VTEP only
interested in IP multicast traffic would also pull all the BULL traffic
and drop it as it is not a member in the originating broadcast domain
[1].

Prepare for this change by allowing the 0.0.0.0 group address in the
common rtnetlink MDB code and forbid it in the bridge driver. A similar
change is not needed for IPv6 because the common code only validates
that the group address is not the all-nodes address.

[1] https://datatracker.ietf.org/doc/html/draft-ietf-bess-evpn-irb-mcast#section-2.6

Signed-off-by: Ido Schimmel 
Reviewed-by: Nikolay Aleksandrov 
Signed-off-by: David S. Miller

rtnetlink: bridge: mcast: Move MDB handlers out of bridge driver

2023-03-17T08:05:48+00:00

Currently, the bridge driver registers handlers for MDB netlink
messages, making it impossible for other drivers to implement MDB
support.

As a preparation for VXLAN MDB support, move the MDB handlers out of the
bridge driver to the core rtnetlink code. The rtnetlink code will call
into individual drivers by invoking their previously added MDB net
device operations.

Note that while the diffstat is large, the change is mechanical. It
moves code out of the bridge driver to rtnetlink code. Also note that a
similar change was made in 2012 with commit 77162022ab26 ("net: add
generic PF_BRIDGE:RTM_ FDB hooks") that moved FDB handlers out of the
bridge driver to the core rtnetlink code.

Signed-off-by: Ido Schimmel 
Reviewed-by: Nikolay Aleksandrov 
Signed-off-by: David S. Miller

net: bridge: Add netlink knobs for number / maximum MDB entries

2023-02-06T08:48:26+00:00

The previous patch added accounting for number of MDB entries per port and
per port-VLAN, and the logic to verify that these values stay within
configured bounds. However it didn't provide means to actually configure
those bounds or read the occupancy. This patch does that.

Two new netlink attributes are added for the MDB occupancy:
IFLA_BRPORT_MCAST_N_GROUPS for the per-port occupancy and
BRIDGE_VLANDB_ENTRY_MCAST_N_GROUPS for the per-port-VLAN occupancy.
And another two for the maximum number of MDB entries:
IFLA_BRPORT_MCAST_MAX_GROUPS for the per-port maximum, and
BRIDGE_VLANDB_ENTRY_MCAST_MAX_GROUPS for the per-port-VLAN one.

Note that the two new IFLA_BRPORT_ attributes prompt bumping of
RTNL_SLAVE_MAX_TYPE to size the slave attribute tables large enough.

The new attributes are used like this:

 # ip link add name br up type bridge vlan_filtering 1 mcast_snooping 1 \
                                      mcast_vlan_snooping 1 mcast_querier 1
 # ip link set dev v1 master br
 # bridge vlan add dev v1 vid 2

 # bridge vlan set dev v1 vid 1 mcast_max_groups 1
 # bridge mdb add dev br port v1 grp 230.1.2.3 temp vid 1
 # bridge mdb add dev br port v1 grp 230.1.2.4 temp vid 1
 Error: bridge: Port-VLAN is already in 1 groups, and mcast_max_groups=1.

 # bridge link set dev v1 mcast_max_groups 1
 # bridge mdb add dev br port v1 grp 230.1.2.3 temp vid 2
 Error: bridge: Port is already in 1 groups, and mcast_max_groups=1.

 # bridge -d link show
 5: v1@v2:  mtu 1500 master br [...]
     [...] mcast_n_groups 1 mcast_max_groups 1

 # bridge -d vlan show
 port              vlan-id
 br                1 PVID Egress Untagged
                     state forwarding mcast_router 1
 v1                1 PVID Egress Untagged
                     [...] mcast_n_groups 1 mcast_max_groups 1
                   2
                     [...] mcast_n_groups 0 mcast_max_groups 0

Signed-off-by: Petr Machata 
Acked-by: Nikolay Aleksandrov 
Reviewed-by: Ido Schimmel 
Signed-off-by: David S. Miller

net: add gso_ipv4_max_size and gro_ipv4_max_size per device

2023-02-02T04:54:27+00:00

This patch introduces gso_ipv4_max_size and gro_ipv4_max_size
per device and adds netlink attributes for them, so that IPV4
BIG TCP can be guarded by a separate tunable in the next patch.

To not break the old application using "gso/gro_max_size" for
IPv4 GSO packets, this patch updates "gso/gro_ipv4_max_size"
in netif_set_gso/gro_max_size() if the new size isn't greater
than GSO_LEGACY_MAX_SIZE, so that nothing will change even if
userspace doesn't realize the new netlink attributes.

Signed-off-by: Xin Long 
Reviewed-by: David Ahern 
Reviewed-by: Eric Dumazet 
Signed-off-by: Jakub Kicinski

net: expose devlink port over rtnetlink

2022-11-04T03:48:37+00:00

Expose devlink port handle related to netdev over rtnetlink. Introduce a
new nested IFLA attribute to carry the info. Call into devlink code to
fill-up the nest with existing devlink attributes that are used over
devlink netlink.

Signed-off-by: Jiri Pirko 
Signed-off-by: Jakub Kicinski

bridge: Add MAC Authentication Bypass (MAB) support

2022-11-04T03:46:32+00:00

Hosts that support 802.1X authentication are able to authenticate
themselves by exchanging EAPOL frames with an authenticator (Ethernet
bridge, in this case) and an authentication server. Access to the
network is only granted by the authenticator to successfully
authenticated hosts.

The above is implemented in the bridge using the "locked" bridge port
option. When enabled, link-local frames (e.g., EAPOL) can be locally
received by the bridge, but all other frames are dropped unless the host
is authenticated. That is, unless the user space control plane installed
an FDB entry according to which the source address of the frame is
located behind the locked ingress port. The entry can be dynamic, in
which case learning needs to be enabled so that the entry will be
refreshed by incoming traffic.

There are deployments in which not all the devices connected to the
authenticator (the bridge) support 802.1X. Such devices can include
printers and cameras. One option to support such deployments is to
unlock the bridge ports connecting these devices, but a slightly more
secure option is to use MAB. When MAB is enabled, the MAC address of the
connected device is used as the user name and password for the
authentication.

For MAB to work, the user space control plane needs to be notified about
MAC addresses that are trying to gain access so that they will be
compared against an allow list. This can be implemented via the regular
learning process with the sole difference that learned FDB entries are
installed with a new "locked" flag indicating that the entry cannot be
used to authenticate the device. The flag cannot be set by user space,
but user space can clear the flag by replacing the entry, thereby
authenticating the device.

Locked FDB entries implement the following semantics with regards to
roaming, aging and forwarding:

1. Roaming: Locked FDB entries can roam to unlocked (authorized) ports,
   in which case the "locked" flag is cleared. FDB entries cannot roam
   to locked ports regardless of MAB being enabled or not. Therefore,
   locked FDB entries are only created if an FDB entry with the given {MAC,
   VID} does not already exist. This behavior prevents unauthenticated
   devices from disrupting traffic destined to already authenticated
   devices.

2. Aging: Locked FDB entries age and refresh by incoming traffic like
   regular entries.

3. Forwarding: Locked FDB entries forward traffic like regular entries.
   If user space detects an unauthorized MAC behind a locked port and
   wishes to prevent traffic with this MAC DA from reaching the host, it
   can do so using tc or a different mechanism.

Enable the above behavior using a new bridge port option called "mab".
It can only be enabled on a bridge port that is both locked and has
learning enabled. Locked FDB entries are flushed from the port once MAB
is disabled. A new option is added because there are pure 802.1X
deployments that are not interested in notifications about locked FDB
entries.

Signed-off-by: Hans J. Schultz 
Signed-off-by: Ido Schimmel 
Acked-by: Nikolay Aleksandrov 
Reviewed-by: Vladimir Oltean 
Signed-off-by: Jakub Kicinski