net: macsec: hardware offloading infrastructure
This patch introduces the MACsec hardware offloading infrastructure. The main idea here is to re-use the logic and data structures of the software MACsec implementation. This allows not to duplicate definitions and structure storing the same kind of information. It also allows to use a unified genlink interface for both MACsec implementations (so that the same userspace tool, `ip macsec`, is used with the same arguments). The MACsec offloading support cannot be disabled if an interface supports it at the moment. The MACsec configuration is passed to device drivers supporting it through macsec_ops which are called from the MACsec genl helpers. Those functions call the macsec ops of PHY and Ethernet drivers in two steps: a preparation one, and a commit one. The first step is allowed to fail and should be used to check if a provided configuration is compatible with the features provided by a MACsec engine, while the second step is not allowed to fail and should only be used to enable a given MACsec configuration. Two extra calls are made: when a virtual MACsec interface is created and when it is deleted, so that the hardware driver can stay in sync. The Rx and TX handlers are modified to take in account the special case were the MACsec transformation happens in the hardware, whether in a PHY or in a MAC, as the packets seen by the networking stack on both the physical and MACsec virtual interface are exactly the same. This leads to some limitations: the hardware and software implementations can't be used on the same physical interface, as the policies would be impossible to fulfill (such as strict validation of the frames). Also only a single virtual MACsec interface can be offloaded to a physical port supporting hardware offloading as it would be impossible to guess onto which interface a given packet should go (for ingress traffic). Another limitation as of now is that the counters and statistics are not reported back from the hardware to the software MACsec implementation. This isn't an issue when using offloaded MACsec transformations, but it should be added in the future so that the MACsec state can be reported to the user (which would also improve the debug). Signed-off-by:Antoine Tenart <antoine.tenart@bootlin.com> Signed-off-by:
David S. Miller <davem@davemloft.net>
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2e181358