The purpose of the Lowest Acceptable PN (lpn) parameters in the MACsec
SAK Use parameter set is to enforce delay protection. Per IEEE Std
802.1X-2010, Clause 9, "Each SecY uses MKA to communicate the lowest PN
used for transmission with the SAK within the last two seconds, allowing
receivers to bound transmission delays."
When encoding the SAK Use parameter set the KaY should set llpn and olpn
to the lowest PN transmitted by the latest SAK and oldest SAK (if
active) within the last two seconds. Because MKPDUs are transmitted
every 2 seconds (MKA_HELLO_TIME), the solution implemented here
calculates lpn based on the txsc->next_pn read during the previous MKPDU
transmit.
Upon receiving and decoding a SAK Use parameter set with delay
protection enabled, the KaY will update the SecY's lpn if the delay
protect lpn is greater than the SecY's current lpn (which is a product
of last PN received and replay protection and window size).
Signed-off-by: Michael Siedzik <msiedzik@extremenetworks.com>
This is specific to the macsec_qca driver. The core implementation
shouldn't care about this, and only deal with the complete secure
channel, and pass this down to the driver.
Drivers that have such limitations should take care of these in their
->create functions and throw an error.
Since the core MKA no longer saves the channel number, the macsec_qca
driver must be able to recover it. Add a map (which is just an array
since it's quite short) to match SCIs to channel numbers, and lookup
functions that will be called in every place where functions would get
the channel from the core code. Getting an available channel should be
part of channel creation, instead of being a preparation step.
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
This also implements the macsec_get_capability for the macsec_qca
driver to maintain the existing behavior.
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
These structs will be passed down to macsec drivers in a coming patch to
make the driver interface cleaner, so they need to be shared between the
core MKA implementation and the drivers.
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
This is a known constant value (CS_ID_LEN, i.e., the length of the EUI64
identifier) and does not need to be provided separately in these
function calls.
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
