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.Dd March 27, 2020 .Dt CRYPTO_ASYM 9 .Os .Sh NAME .Nm crypto_asym .Nd asymmetric cryptographic operations .Sh SYNOPSIS n opencrypto/cryptodev.h .Ft int .Fn crypto_kdispatch "struct cryptkop *krp" .Ft void .Fn crypto_kdone "struct cryptkop *krp" .Ft int .Fn crypto_kregister "uint32_t driverid" "int kalg" "uint32_t flags" .Ft int .Fn CRYPTODEV_KPROCESS "device_t dev" "struct cryptop *krp" "int flags" .Sh DESCRIPTION The in-kernel cryptographic kernel framework supports asymmetric requests (keying requests) in addition to symmetric operations. There are currently no in-kernel users of these requests, but applications can make requests of hardware drivers via the
p Some APIs are shared with the framework's symmetric request support. This manual describes the APIs and data structures unique to asymmetric requests.
p .Ss Request Objects A request is described by a .Vt struct cryptkop containing the following fields: l -tag -width "krp_callback" t Fa krp_op Operation to perform. Available operations include .Dv CRK_MOD_EXP , .Dv CRK_MOD_EXP_CRT , .Dv CRK_DSA_SIGN , .Dv CRK_DSA_VERIFY , and .Dv CRK_DH_COMPUTE_KEY . t Fa krp_status Error status. Either zero on success, or an error if an operation fails. Set by drivers prior to completing a request via .Fn crypto_kdone . t Fa krp_iparams Count of input parameters. t Fa krp_oparams Count of output parameters. t Fa krp_crid Requested device. t Fa krp_hid Device used to complete the request. t Fa krp_param Array of parameters. The array contains the input parameters first followed by the output parameters. Each parameter is stored as a bignum. Each bignum is described by a .Vt struct crparam containing the following fields: l -tag -width "crp_nbits" t Fa crp_p Pointer to array of packed bytes. t Fa crp_nbits Size of bignum in bits. .El t Fa krp_callback Callback function. This must point to a callback function of type .Vt void (*)(struct cryptkop *) . The callback function should inspect .Fa krp_status to determine the status of the completed operation. .El
p New requests should be initialized to zero before setting fields to appropriate values. Once the request has been populated, it should be passed to .Fn crypto_kdispatch .
p .Fn crypto_kdispatch will choose a device driver to perform the operation described by .Fa krp and invoke that driver's .Fn CRYPTO_KPROCESS method. .Ss Driver API Drivers register support for asymmetric operations by calling .Fn crypto_kregister for each supported algorithm. .Fa driverid should be the value returned by an earlier call to .Fn crypto_get_driverid . .Fa kalg should list one of the operations that can be set in .Fa krp_op . .Fa flags is a bitmask of zero or more of the following values: l -tag -width "CRYPTO_ALG_FLAG_RNG_ENABLE" t Dv CRYPTO_ALG_FLAG_RNG_ENABLE Device has a hardware RNG for DH/DSA. t Dv CRYPTO_ALG_FLAG_DSA_SHA Device can compute a SHA digest of a message. .El
p Drivers unregister with the framework via .Fn crypto_unregister_all .
p Similar to .Fn CRYPTO_PROCESS , .Fn CRYPTO_KPROCESS should complete the request or schedule it for asynchronous completion. If this method is not able to complete a request due to insufficient resources, it can defer the request (and future asymmetric requests) by returning .Dv ERESTART . Once resources are available, the driver should invoke .Fn crypto_unblock with .Dv CRYPTO_ASYMQ to resume processing of asymmetric requests.
p Once a request is completed, the driver should set .Fa krp_status and then call .Fn crypto_kdone . .Sh RETURN VALUES .Fn crypto_kdispatch , .Fn crypto_kregister , and .Fn CRYPTODEV_KPROCESS return zero on success or an error on failure. .Sh SEE ALSO .Xr crypto 7 , .Xr crypto 9 , .Xr crypto_driver 9 , .Xr crypto_request 9 , .Xr crypto_session 9