Merge branch 'nfp-flower-vxlan-tunnel-offload'

Simon Horman says:

====================
nfp: flower vxlan tunnel offload

John says:

This patch set allows offloading of TC flower match and set tunnel fields
to the NFP. The initial focus is on VXLAN traffic. Due to the current
state of the NFP firmware, only VXLAN traffic on well known port 4789 is
handled. The match and action fields must explicity set this value to be
supported. Tunnel end point information is also offloaded to the NFP for
both encapsulation and decapsulation. The NFP expects 3 separate data sets
to be supplied.

For decapsulation, 2 separate lists exist; a list of MAC addresses
referenced by an index comprised of the port number, and a list of IP
addresses. These IP addresses are not connected to a MAC or port. The MAC
addresses can be written as a block or one at a time (because they have an
index, previous values can be overwritten) while the IP addresses are
always written as a list of all the available IPs. Because the MAC address
used as a tunnel end point may be associated with a physical port or may
be a virtual netdev like an OVS bridge, we do not know which addresses
should be offloaded. For this reason, all MAC addresses of active netdevs
are offloaded to the NFP. A notifier checks for changes to any currently
offloaded MACs or any new netdevs that may occur. For IP addresses, the
tunnel end point used in the rules is known as the destination IP address
must be specified in the flower classifier rule. When a new IP address
appears in a rule, the IP address is offloaded. The IP is removed from the
offloaded list when all rules matching on that IP are deleted.

For encapsulation, a next hop table is updated on the NFP that contains
the source/dest IPs, MACs and egress port. These are written individually
when requested. If the NFP tries to encapsulate a packet but does not know
the next hop, then is sends a request to the host. The host carries out a
route lookup and populates the given entry on the NFP table. A notifier
also exists to check for any links changing or going down in the kernel
next hop table. If an offloaded next hop entry is removed from the kernel
then it is also removed on the NFP.

The NFP periodically sends a message to the host telling it which tunnel
ports have packets egressing the system. The host uses this information to
update the used value in the neighbour entry. This means that, rather than
expire when it times out, the kernel will send an ARP to check if the link
is still live. From an NFP perspective, this means that valid entries will
not be removed from its next hop table.
====================

Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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