int32_t
crypto_get_driverid(
u_int32_t
)
int
crypto_register(
u_int32_t
, int
, u_int16_t
, u_int32_t
, int (*)(void *, u_int32_t *, struct cryptoini *)
, int (*)(void *, u_int32_t *)
, int (*)(u_int64_t)
, int (*)(struct cryptop *)
, void *
)
int
crypto_kregister(
u_int32_t
, int
, u_int32_t
, int (*)(void *, struct cryptkop *, int)
, void *
)
int
crypto_unregister(
u_int32_t
, int
)
void
crypto_done(
struct cryptop *
)
void
crypto_kdone(
struct cryptkop *
)
int
crypto_newsession(
u_int64_t *
, struct cryptoini *
, int
)
int
crypto_freesession(
u_int64_t
)
int
crypto_dispatch(
struct cryptop *
)
int
crypto_kdispatch(
struct cryptkop *
)
struct
cryptop
*
crypto_getreq(
int
)
void
crypto_freereq(
struct cryptop *
)
#define EALG_MAX_BLOCK_LEN 16
struct cryptoini {
int cri_alg;
int cri_klen;
int cri_rnd;
void *cri_key;
u_int8_t cri_iv[EALG_MAX_BLOCK_LEN];
struct cryptoini *cri_next;
};
struct cryptodesc {
int crd_skip;
int crd_len;
int crd_inject;
int crd_flags;
struct cryptoini CRD_INI;
struct cryptodesc *crd_next;
};
struct cryptop {
TAILQ_ENTRY(cryptop) crp_next;
u_int64_t crp_sid;
int crp_ilen;
int crp_olen;
int crp_etype;
int crp_flags;
void *crp_buf;
void *crp_opaque;
struct cryptodesc *crp_desc;
int (*crp_callback)(struct cryptop *);
void *crp_mac;
};
struct crparam {
void *crp_p;
u_int crp_nbits;
};
#define CRK_MAXPARAM 8
struct cryptkop {
TAILQ_ENTRY(cryptkop) krp_next;
u_int krp_op; /* ie. CRK_MOD_EXP or other */
u_int krp_status; /* return status */
u_short krp_iparams; /* # of input parameters */
u_short krp_oparams; /* # of output parameters */
u_int32_t krp_hid;
struct crparam krp_param[CRK_MAXPARAM]; /* kvm */
int (*krp_callback)(struct cryptkop *);
};
Keying operations are supported as well. Unlike the symmetric operators described above, these sessionless commands perform mathematical operations using input and output parameters.
Since the consumers may not be associated with a process, drivers may
not use condition variables:
condvar(9).
The same holds for the framework.
Thus, a callback mechanism is used
to notify a consumer that a request has been completed (the
callback is specified by the consumer on an per-request basis).
The callback is invoked by the framework whether the request was
successfully completed or not.
An error indication is provided in the latter case.
A specific error code,
EAGAIN
,
is used to indicate that a session number has changed and that the
request may be re-submitted immediately with the new session number.
Errors are only returned to the invoking function if not
enough information to call the callback is available (meaning, there
was a fatal error in verifying the arguments).
No callback mechanism is used for session initialization and teardown.
The
crypto_newsession()
routine is called by consumers of cryptographic services (such as the
ipsec(4)
stack) that wish to establish a new session with the framework.
On success, the first argument will contain the Session Identifier (SID).
The second argument contains all the necessary information for
the driver to establish the session.
The third argument indicates whether a
hardware driver should be used (1) or not (0).
The various fields in the
cryptoini
structure are:
cri_alg
CRYPTO_DES_CBC
CRYPTO_3DES_CBC
CRYPTO_BLF_CBC
CRYPTO_CAST_CBC
CRYPTO_SKIPJACK_CBC
CRYPTO_MD5_HMAC
CRYPTO_SHA1_HMAC
CRYPTO_RIPEMD160_HMAC
CRYPTO_MD5_KPDK
CRYPTO_SHA1_KPDK
CRYPTO_AES_CBC
CRYPTO_ARC4
CRYPTO_MD5
CRYPTO_SHA1
cri_klen
cri_rnd
cri_key
cri_iv
cri_next
cryptoini
structure.
Multiple such structures may be linked to establish multi-algorithm sessions
(ipsec(4)
is an example consumer of such a feature).
The
cryptoini
structure and its contents will not be modified by the framework (or
the drivers used).
Subsequent requests for processing that use the
SID returned will avoid the cost of re-initializing the hardware (in
essence, SID acts as an index in the session cache of the driver).
crypto_freesession()
is called with the SID returned by
crypto_newsession(
)
to disestablish the session.
crypto_dispatch()
is called to process a request.
The various fields in the
cryptop
structure are:
crp_sid
crp_ilen
crp_olen
crd_skip
.
For symmetric crypto operations, this will be the same as the input length.
crp_alloctype
crp_callback
)
routine.
If the request was not successful, an error code is set in the
crp_etype
field.
It is the responsibility of the callback routine to set the appropriate
spl(9)
level.
crp_etype
EAGAIN
error code is returned, the SID has changed (and has been recorded in the
crp_sid
field).
The consumer should record the new SID and use it in all subsequent requests.
In this case, the request may be re-submitted immediately.
This mechanism is used by the framework to perform
session migration (move a session from one driver to another, because
of availability, performance, or other considerations).
Note that this field only makes sense when examined by
the callback routine specified in
crp_callback
.
Errors are returned to the invoker of
crypto_process()
only when enough information is not present to call the callback
routine (i.e., if the pointer passed is
NULL
or if no callback routine was specified).
crp_flags
CRYPTO_F_IMBUF
crp_buf
is an mbuf chain.
crp_buf
crp_alloctype
),
depending on
crp_flags
.
crp_opaque
crp_desc
crd_skip
crd_len
crd_skip
,
should be processed.
crd_inject
crd_flags
).
For MAC algorithms, this is where the result of the keyed hash will be
inserted.
crd_flags
CRD_F_ENCRYPT
CRD_F_IV_PRESENT
crd_inject
value will be ignored and no IV will be written in the buffer.
Otherwise, the IV used to encrypt the packet will be written
at the location pointed to by
crd_inject
.
The IV length is assumed to be equal to the blocksize of the
encryption algorithm.
Some applications that do special
``IV cooking'',
such as the half-IV mode in
ipsec(4),
can use this flag to indicate that the IV should not be written on the packet.
This flag is typically used in conjunction with the
CRD_F_IV_EXPLICIT
flag.
CRD_F_IV_EXPLICIT
crd_iv
fields.
Otherwise, for encryption operations the IV is provided for by
the driver used to perform the operation, whereas for decryption
operations it is pointed to by the
crd_inject
field.
This flag is typically used when the IV is calculated
``on the fly''
by the consumer, and does not precede the data (some
ipsec(4)
configurations, and the encrypted swap are two such examples).
CRD_F_COMP
CRD_INI
cryptoini
structure will not be modified by the framework or the device drivers.
Since this information accompanies every cryptographic
operation request, drivers may re-initialize state on-demand
(typically an expensive operation).
Furthermore, the cryptographic
framework may re-route requests as a result of full queues or hardware
failure, as described above.
crd_next
crypto_getreq()
allocates a
cryptop
structure with a linked list of as many
cryptodesc
structures as were specified in the argument passed to it.
crypto_freereq()
deallocates a structure
cryptop
and any
cryptodesc
structures linked to it.
Note that it is the responsibility of the
callback routine to do the necessary cleanups associated with the
opaque field in the
cryptop
structure.
crypto_kdispatch()
is called to perform a keying operation.
The various fields in the
crytokop
structure are:
krp_op
krp_status
krp_iparams
krp_oparams
krp_kvp
krp_hid
krp_callback
),
crypto_register(
),
crypto_kregister(
),
crypto_unregister(
),
and
crypto_done(
)
routines are used by drivers that provide support for cryptographic
primitives to register and unregister with the kernel crypto services
framework.
Drivers must first use the
crypto_get_driverid(
)
function to acquire a driver identifier, specifying the
flags
as an argument (normally 0, but software-only drivers should specify
CRYPTOCAP_F_SOFTWARE
).
For each algorithm the driver supports, it must then call
crypto_register(
).
The first argument is the driver identifier.
The second argument is an array of
CRYPTO_ALGORITHM_MAX
+
1
elements, indicating which algorithms are supported.
The last three arguments are pointers to three
driver-provided functions that the framework may call to establish new
cryptographic context with the driver, free already established
context, and ask for a request to be processed (encrypt, decrypt,
etc.)
crypto_unregister(
)
is called by drivers that wish to withdraw support for an algorithm.
The two arguments are the driver and algorithm identifiers, respectively.
Typically, drivers for
pcmcia(4)
crypto cards that are being ejected will invoke this routine for all
algorithms supported by the card.
If called with
CRYPTO_ALGORITHM_ALL
,
all algorithms registered for a driver will be unregistered in one go
and the driver will be disabled (no new sessions will be allocated on
that driver, and any existing sessions will be migrated to other
drivers).
The same will be done if all algorithms associated with a driver are
unregistered one by one.
The calling convention for the three driver-supplied routines is:
int (*newsession) (void *, u_int32_t *, struct cryptoini *);
int (*freesession) (void *, u_int64_t);
int (*process) (void *, struct cryptop *, int);
On invocation, the first argument to
newsession()
contains the driver identifier obtained via
crypto_get_driverid(
).
On successfully returning, it should contain a driver-specific session
identifier.
The second argument is identical to that of
crypto_newsession(
).
The
freesession()
routine takes as argument the SID (which is the concatenation of the
driver identifier and the driver-specific session identifier).
It should clear any context associated with the session (clear hardware
registers, memory, etc.).
The
process()
routine is invoked with a request to perform crypto processing.
This routine must not block, but should queue the request and return
immediately.
Upon processing the request, the callback routine should be invoked.
In case of error, the error indication must be placed in the
crp_etype
field of the
cryptop
structure.
The
hint
argument can be set to
CRYPTO_HINT_MORE
the there will be more request right after this request.
When the request is completed, or an error is detected, the
process()
routine should invoke
crypto_done(
).
Session migration may be performed, as mentioned previously.
The
kprocess()
routine is invoked with a request to perform crypto key processing.
This routine must not block, but should queue the request and return
immediately.
Upon processing the request, the callback routine should be invoked.
In case of error, the error indication must be placed in the
krp_status
field of the
cryptkop
structure.
When the request is completed, or an error is detected, the
kprocess()
routine should invoke
crypto_kdone(
).
),
crypto_kregister(
),
crypto_unregister(
),
crypto_newsession(
),
and
crypto_freesession(
)
return 0 on success, or an error code on failure.
crypto_get_driverid(
)
returns a non-negative value on error, and -1 on failure.
crypto_getreq(
)
returns a pointer to a
cryptop
structure and
NULL
on failure.
crypto_dispatch(
)
returns
EINVAL
if its argument or the callback function was
NULL
,
and 0 otherwise.
The callback is provided with an error code in case of failure, in the
crp_etype
field.
sys/crypto/crypto.c
Sam Leffler
ported the crypto framework to
FreeBSD
and made performance improvements.
Jonathan Stone <jonathan@NetBSD.org>
ported the cryptoframe from
FreeBSD
to
NetBSD.
opencrypto
first appeared in
NetBSD2.0.
)
operation must be available by the same driver.
If that's not the case, session initialization will fail.
The framework also needs a mechanism for determining which driver is best for a specific set of algorithms associated with a session. Some type of benchmarking is in order here.
Multiple instances of the same algorithm in the same session are not supported. Note that 3DES is considered one algorithm (and not three instances of DES). Thus, 3DES and DES could be mixed in the same request.
A queue for completed operations should be implemented and processed at some software spl(9) level, to avoid overall system latency issues, and potential kernel stack exhaustion while processing a callback.
When SMP time comes, we will support use of a second processor (or more) as a crypto device (this is actually AMP, but we need the same basic support).