udp_tunnel: Use flex array to simplify code

'n_tables' is small, UDP_TUNNEL_NIC_MAX_TABLES = 4 as a maximum. So there
is no real point to allocate the 'entries' pointers array with a dedicate
memory allocation.

Using a flexible array for struct udp_tunnel_nic->entries avoids the
overhead of an additional memory allocation.

This also saves an indirection when the array is accessed.

Finally, __counted_by() can be used for run-time bounds checking if
configured and supported by the compiler.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://lore.kernel.org/r/4a096ba9cf981a588aa87235bb91e933ee162b3d.1695542544.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

udp_tunnel: Add checks for nla_nest_start() in __udp_tunnel_nic_dump_write()

As the nla_nest_start() may fail with NULL returned, the return value
should be checked.

Note that this is not a real bug, nothing will break here.
The next nla_put() will fail as well and we'll bail (and
nla_nest_cancel() can handle NULL). But we keep getting
those "fixes" so whatever.

Signed-off-by: Yuan Can <yuancan@huawei.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20221129013934.55184-1-yuancan@huawei.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

udp_tunnel: Fix end of loop test in udp_tunnel_nic_unregister()

This test is checking if we exited the list via break or not. However
if it did not exit via a break then "node" does not point to a valid
udp_tunnel_nic_shared_node struct. It will work because of the way
the structs are laid out it's the equivalent of
"if (info->shared->udp_tunnel_nic_info != dev)" which will always be
true, but it's not the right way to test.

Fixes: 74cc6d182d03 ("udp_tunnel: add the ability to share port tables")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

udp_tunnel: Fix udp_tunnel_nic work-queue type

Turn udp_tunnel_nic work-queue to an ordered work-queue. This queue
holds the UDP-tunnel configuration commands of the different netdevs.
When the netdevs are functions of the same NIC the order of
execution may be crucial.

Problem example:
NIC with 2 PFs, both PFs declare offload quota of up to 3 UDP-ports.
$ifconfig eth2 1.1.1.1/16 up

$ip link add eth2_19503 type vxlan id 5049 remote 1.1.1.2 dev eth2 dstport 19053
$ip link set dev eth2_19503 up

$ip link add eth2_19504 type vxlan id 5049 remote 1.1.1.3 dev eth2 dstport 19054
$ip link set dev eth2_19504 up

$ip link add eth2_19505 type vxlan id 5049 remote 1.1.1.4 dev eth2 dstport 19055
$ip link set dev eth2_19505 up

$ip link add eth2_19506 type vxlan id 5049 remote 1.1.1.5 dev eth2 dstport 19056
$ip link set dev eth2_19506 up

NIC RX port offload infrastructure offloads the first 3 UDP-ports (on
all devices which sets NETIF_F_RX_UDP_TUNNEL_PORT feature) and not
UDP-port 19056. So both PFs gets this offload configuration.

$ip link set dev eth2_19504 down

This triggers udp-tunnel-core to remove the UDP-port 19504 from
offload-ports-list and offload UDP-port 19056 instead.

In this scenario it is important that the UDP-port of 19504 will be
removed from both PFs before trying to add UDP-port 19056. The NIC can
stop offloading a UDP-port only when all references are removed.
Otherwise the NIC may report exceeding of the offload quota.

Fixes: cc4e3835eff4 ("udp_tunnel: add central NIC RX port offload infrastructure")
Signed-off-by: Aya Levin <ayal@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

udp_tunnel: add the ability to share port tables

Unfortunately recent Intel NIC designs share the UDP port table
across netdevs. So far the UDP tunnel port state was maintained
per netdev, we need to extend that to cater to Intel NICs.

Expect NICs to allocate the info structure dynamically and link
to the state from there. All the shared NICs will record port
offload information in the one instance of the table so we need
to make sure that the use count can accommodate larger numbers.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

udp_tunnel: add the ability to hard-code IANA VXLAN

mlx5 has the IANA VXLAN port (4789) hard coded by the device,
instead of being added dynamically when tunnels are created.

To support this add a workaround flag to struct udp_tunnel_nic_info.
Skipping updates for the port is fairly trivial, dumping the hard
coded port via ethtool requires some code duplication. The port
is not a part of any real table, we dump it in a special table
which has no tunnel types supported and only one entry.

This is the last known workaround / hack needed to convert
all drivers to the new infra.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

ethtool: add tunnel info interface

Add an interface to report offloaded UDP ports via ethtool netlink.

Now that core takes care of tracking which UDP tunnel ports the NICs
are aware of we can quite easily export this information out to
user space.

The responsibility of writing the netlink dumps is split between
ethtool code and udp_tunnel_nic.c - since udp_tunnel module may
not always be loaded, yet we should always report the capabilities
of the NIC.

$ ethtool --show-tunnels eth0
Tunnel information for eth0:
UDP port table 0:
Size: 4
Types: vxlan
No entries
UDP port table 1:
Size: 4
Types: geneve, vxlan-gpe
Entries (1):
port 1230, vxlan-gpe

v4:
- back to v2, build fix is now directly in udp_tunnel.h
v3:
- don't compile ETHTOOL_MSG_TUNNEL_INFO_GET in if CONFIG_INET
not set.
v2:
- fix string set count,
- reorder enums in the uAPI,
- fix type of ETHTOOL_A_TUNNEL_UDP_TABLE_TYPES to bitset
in docs and comments.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

udp_tunnel: add central NIC RX port offload infrastructure

Cater to devices which:
(a) may want to sleep in the callbacks;
(b) only have IPv4 support;
(c) need all the programming to happen while the netdev is up.

Drivers attach UDP tunnel offload info struct to their netdevs,
where they declare how many UDP ports of various tunnel types
they support. Core takes care of tracking which ports to offload.

Use a fixed-size array since this matches what almost all drivers
do, and avoids a complexity and uncertainty around memory allocations
in an atomic context.

Make sure that tunnel drivers don't try to replay the ports when
new NIC netdev is registered. Automatic replays would mess up
reference counting, and will be removed completely once all drivers
are converted.

v4:
- use a #define NULL to avoid build issues with CONFIG_INET=n.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>