Sync acpiconf with FreeBSD 7.2.

[dragonfly.git] / sys / opencrypto / crypto.c

/*      $FreeBSD: src/sys/opencrypto/crypto.c,v 1.28 2007/10/20 23:23:22 julian Exp $   */
/*-
 * Copyright (c) 2002-2006 Sam Leffler.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * Cryptographic Subsystem.
 *
 * This code is derived from the Openbsd Cryptographic Framework (OCF)
 * that has the copyright shown below.  Very little of the original
 * code remains.
 */

/*-
 * The author of this code is Angelos D. Keromytis (angelos@cis.upenn.edu)
 *
 * This code was written by Angelos D. Keromytis in Athens, Greece, in
 * February 2000. Network Security Technologies Inc. (NSTI) kindly
 * supported the development of this code.
 *
 * Copyright (c) 2000, 2001 Angelos D. Keromytis
 *
 * Permission to use, copy, and modify this software with or without fee
 * is hereby granted, provided that this entire notice is included in
 * all source code copies of any software which is or includes a copy or
 * modification of this software.
 *
 * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY
 * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE
 * MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR
 * PURPOSE.
 */

#define CRYPTO_TIMING                           /* enable timing support */

#include "opt_ddb.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/eventhandler.h>
#include <sys/kernel.h>
#include <sys/kthread.h>
#include <sys/lock.h>
#include <sys/module.h>
#include <sys/malloc.h>
#include <sys/proc.h>
#include <sys/sysctl.h>
#include <sys/thread2.h>

#include <vm/vm_zone.h>

#include <ddb/ddb.h>

#include <opencrypto/cryptodev.h>
#include <opencrypto/xform.h>                   /* XXX for M_XDATA */

#include <sys/kobj.h>
#include <sys/bus.h>
#include "cryptodev_if.h"

/*
 * Crypto drivers register themselves by allocating a slot in the
 * crypto_drivers table with crypto_get_driverid() and then registering
 * each algorithm they support with crypto_register() and crypto_kregister().
 */
static  struct lock crypto_drivers_lock;        /* lock on driver table */
#define CRYPTO_DRIVER_LOCK()    lockmgr(&crypto_drivers_lock, LK_EXCLUSIVE)
#define CRYPTO_DRIVER_UNLOCK()  lockmgr(&crypto_drivers_lock, LK_RELEASE)
#define CRYPTO_DRIVER_ASSERT()  KKASSERT(lockstatus(&crypto_drivers_lock, curthread) != 0)

/*
 * Crypto device/driver capabilities structure.
 *
 * Synchronization:
 * (d) - protected by CRYPTO_DRIVER_LOCK()
 * (q) - protected by CRYPTO_Q_LOCK()
 * Not tagged fields are read-only.
 */
struct cryptocap {
        device_t        cc_dev;                 /* (d) device/driver */
        u_int32_t       cc_sessions;            /* (d) # of sessions */
        u_int32_t       cc_koperations;         /* (d) # os asym operations */
        /*
         * Largest possible operator length (in bits) for each type of
         * encryption algorithm. XXX not used
         */
        u_int16_t       cc_max_op_len[CRYPTO_ALGORITHM_MAX + 1];
        u_int8_t        cc_alg[CRYPTO_ALGORITHM_MAX + 1];
        u_int8_t        cc_kalg[CRK_ALGORITHM_MAX + 1];

        int             cc_flags;               /* (d) flags */
#define CRYPTOCAP_F_CLEANUP     0x80000000      /* needs resource cleanup */
        int             cc_qblocked;            /* (q) symmetric q blocked */
        int             cc_kqblocked;           /* (q) asymmetric q blocked */
};
static  struct cryptocap *crypto_drivers = NULL;
static  int crypto_drivers_num = 0;

/*
 * There are two queues for crypto requests; one for symmetric (e.g.
 * cipher) operations and one for asymmetric (e.g. MOD) operations.
 * See below for how synchronization is handled.
 * A single lock is used to lock access to both queues.  We could
 * have one per-queue but having one simplifies handling of block/unblock
 * operations.
 */
static  int crp_sleep = 0;
static  TAILQ_HEAD(,cryptop) crp_q;             /* request queues */
static  TAILQ_HEAD(,cryptkop) crp_kq;
static  struct lock crypto_q_lock;
#define CRYPTO_Q_LOCK()         lockmgr(&crypto_q_lock, LK_EXCLUSIVE)
#define CRYPTO_Q_UNLOCK()       lockmgr(&crypto_q_lock, LK_RELEASE)

/*
 * There are two queues for processing completed crypto requests; one
 * for the symmetric and one for the asymmetric ops.  We only need one
 * but have two to avoid type futzing (cryptop vs. cryptkop).  A single
 * lock is used to lock access to both queues.  Note that this lock
 * must be separate from the lock on request queues to insure driver
 * callbacks don't generate lock order reversals.
 */
static  TAILQ_HEAD(,cryptop) crp_ret_q;         /* callback queues */
static  TAILQ_HEAD(,cryptkop) crp_ret_kq;
static  struct lock crypto_ret_q_lock;
#define CRYPTO_RETQ_LOCK()      lockmgr(&crypto_ret_q_lock, LK_EXCLUSIVE)
#define CRYPTO_RETQ_UNLOCK()    lockmgr(&crypto_ret_q_lock, LK_RELEASE)
#define CRYPTO_RETQ_EMPTY()     (TAILQ_EMPTY(&crp_ret_q) && TAILQ_EMPTY(&crp_ret_kq))

/*
 * Crypto op and desciptor data structures are allocated
 * from separate private zones.
 */
static  vm_zone_t cryptop_zone;
static  vm_zone_t cryptodesc_zone;

int     crypto_userasymcrypto = 1;      /* userland may do asym crypto reqs */
SYSCTL_INT(_kern, OID_AUTO, userasymcrypto, CTLFLAG_RW,
           &crypto_userasymcrypto, 0,
           "Enable/disable user-mode access to asymmetric crypto support");
int     crypto_devallowsoft = 0;        /* only use hardware crypto for asym */
SYSCTL_INT(_kern, OID_AUTO, cryptodevallowsoft, CTLFLAG_RW,
           &crypto_devallowsoft, 0,
           "Enable/disable use of software asym crypto support");

MALLOC_DEFINE(M_CRYPTO_DATA, "crypto", "crypto session records");

static  void crypto_proc(void);
static  struct thread *cryptothread;
static  void crypto_ret_proc(void);
static  struct thread *cryptoretthread;
static  void crypto_destroy(void);
static  int crypto_invoke(struct cryptocap *cap, struct cryptop *crp, int hint);
static  int crypto_kinvoke(struct cryptkop *krp, int flags);

static struct cryptostats cryptostats;
SYSCTL_STRUCT(_kern, OID_AUTO, crypto_stats, CTLFLAG_RW, &cryptostats,
            cryptostats, "Crypto system statistics");

#ifdef CRYPTO_TIMING
static  int crypto_timing = 0;
SYSCTL_INT(_debug, OID_AUTO, crypto_timing, CTLFLAG_RW,
           &crypto_timing, 0, "Enable/disable crypto timing support");
#endif

static int
crypto_init(void)
{
        int error;

        lockinit(&crypto_drivers_lock, "crypto driver table", 0, LK_CANRECURSE);

        TAILQ_INIT(&crp_q);
        TAILQ_INIT(&crp_kq);
        lockinit(&crypto_q_lock, "crypto op queues", 0, LK_CANRECURSE);

        TAILQ_INIT(&crp_ret_q);
        TAILQ_INIT(&crp_ret_kq);
        lockinit(&crypto_ret_q_lock, "crypto return queues", 0, LK_CANRECURSE);

        cryptop_zone = zinit("cryptop", sizeof (struct cryptop), 0, 0, 1);
        cryptodesc_zone = zinit("cryptodesc", sizeof (struct cryptodesc),
                                0, 0, 1);
        if (cryptodesc_zone == NULL || cryptop_zone == NULL) {
                kprintf("crypto_init: cannot setup crypto zones\n");
                error = ENOMEM;
                goto bad;
        }

        crypto_drivers_num = CRYPTO_DRIVERS_INITIAL;
        crypto_drivers = kmalloc(crypto_drivers_num *
            sizeof(struct cryptocap), M_CRYPTO_DATA, M_NOWAIT | M_ZERO);
        if (crypto_drivers == NULL) {
                kprintf("crypto_init: cannot malloc driver table\n");
                error = ENOMEM;
                goto bad;
        }

        error = kthread_create((void (*)(void *)) crypto_proc, NULL,
                    &cryptothread, "crypto");
        if (error) {
                kprintf("crypto_init: cannot start crypto thread; error %d",
                        error);
                goto bad;
        }

        error = kthread_create((void (*)(void *)) crypto_ret_proc, NULL,
                    &cryptoretthread, "crypto returns");
        if (error) {
                kprintf("crypto_init: cannot start cryptoret thread; error %d",
                        error);
                goto bad;
        }
        return 0;
bad:
        crypto_destroy();
        return error;
}

/*
 * Signal a crypto thread to terminate.  We use the driver
 * table lock to synchronize the sleep/wakeups so that we
 * are sure the threads have terminated before we release
 * the data structures they use.  See crypto_finis below
 * for the other half of this song-and-dance.
 */
static void
crypto_terminate(struct thread **tp, void *q)
{
        struct thread *t;

        KKASSERT(lockstatus(&crypto_drivers_lock, curthread) != 0);
        t = *tp;
        *tp = NULL;
        if (t) {
                kprintf("crypto_terminate: start\n");
                wakeup_one(q);
                crit_enter();
                tsleep_interlock(t, 0);
                CRYPTO_DRIVER_UNLOCK(); /* let crypto_finis progress */
                crit_exit();
                tsleep(t, PINTERLOCKED, "crypto_destroy", 0);
                CRYPTO_DRIVER_LOCK();
                kprintf("crypto_terminate: end\n");
        }
}

static void
crypto_destroy(void)
{
        /*
         * Terminate any crypto threads.
         */
        CRYPTO_DRIVER_LOCK();
        crypto_terminate(&cryptothread, &crp_q);
        crypto_terminate(&cryptoretthread, &crp_ret_q);
        CRYPTO_DRIVER_UNLOCK();

        /* XXX flush queues??? */

        /*
         * Reclaim dynamically allocated resources.
         */
        if (crypto_drivers != NULL)
                kfree(crypto_drivers, M_CRYPTO_DATA);

        if (cryptodesc_zone != NULL)
                zdestroy(cryptodesc_zone);
        if (cryptop_zone != NULL)
                zdestroy(cryptop_zone);
        lockuninit(&crypto_q_lock);
        lockuninit(&crypto_ret_q_lock);
        lockuninit(&crypto_drivers_lock);
}

static struct cryptocap *
crypto_checkdriver(u_int32_t hid)
{
        if (crypto_drivers == NULL)
                return NULL;
        return (hid >= crypto_drivers_num ? NULL : &crypto_drivers[hid]);
}

/*
 * Compare a driver's list of supported algorithms against another
 * list; return non-zero if all algorithms are supported.
 */
static int
driver_suitable(const struct cryptocap *cap, const struct cryptoini *cri)
{
        const struct cryptoini *cr;

        /* See if all the algorithms are supported. */
        for (cr = cri; cr; cr = cr->cri_next)
                if (cap->cc_alg[cr->cri_alg] == 0)
                        return 0;
        return 1;
}

/*
 * Select a driver for a new session that supports the specified
 * algorithms and, optionally, is constrained according to the flags.
 * The algorithm we use here is pretty stupid; just use the
 * first driver that supports all the algorithms we need. If there
 * are multiple drivers we choose the driver with the fewest active
 * sessions.  We prefer hardware-backed drivers to software ones.
 *
 * XXX We need more smarts here (in real life too, but that's
 * XXX another story altogether).
 */
static struct cryptocap *
crypto_select_driver(const struct cryptoini *cri, int flags)
{
        struct cryptocap *cap, *best;
        int match, hid;

        CRYPTO_DRIVER_ASSERT();

        /*
         * Look first for hardware crypto devices if permitted.
         */
        if (flags & CRYPTOCAP_F_HARDWARE)
                match = CRYPTOCAP_F_HARDWARE;
        else
                match = CRYPTOCAP_F_SOFTWARE;
        best = NULL;
again:
        for (hid = 0; hid < crypto_drivers_num; hid++) {
                cap = &crypto_drivers[hid];
                /*
                 * If it's not initialized, is in the process of
                 * going away, or is not appropriate (hardware
                 * or software based on match), then skip.
                 */
                if (cap->cc_dev == NULL ||
                    (cap->cc_flags & CRYPTOCAP_F_CLEANUP) ||
                    (cap->cc_flags & match) == 0)
                        continue;

                /* verify all the algorithms are supported. */
                if (driver_suitable(cap, cri)) {
                        if (best == NULL ||
                            cap->cc_sessions < best->cc_sessions)
                                best = cap;
                }
        }
        if (best != NULL)
                return best;
        if (match == CRYPTOCAP_F_HARDWARE && (flags & CRYPTOCAP_F_SOFTWARE)) {
                /* sort of an Algol 68-style for loop */
                match = CRYPTOCAP_F_SOFTWARE;
                goto again;
        }
        return best;
}

/*
 * Create a new session.  The crid argument specifies a crypto
 * driver to use or constraints on a driver to select (hardware
 * only, software only, either).  Whatever driver is selected
 * must be capable of the requested crypto algorithms.
 */
int
crypto_newsession(u_int64_t *sid, struct cryptoini *cri, int crid)
{
        struct cryptocap *cap;
        u_int32_t hid, lid;
        int err;

        CRYPTO_DRIVER_LOCK();
        if ((crid & (CRYPTOCAP_F_HARDWARE | CRYPTOCAP_F_SOFTWARE)) == 0) {
                /*
                 * Use specified driver; verify it is capable.
                 */
                cap = crypto_checkdriver(crid);
                if (cap != NULL && !driver_suitable(cap, cri))
                        cap = NULL;
        } else {
                /*
                 * No requested driver; select based on crid flags.
                 */
                cap = crypto_select_driver(cri, crid);
                /*
                 * if NULL then can't do everything in one session.
                 * XXX Fix this. We need to inject a "virtual" session
                 * XXX layer right about here.
                 */
        }
        if (cap != NULL) {
                /* Call the driver initialization routine. */
                hid = cap - crypto_drivers;
                lid = hid;              /* Pass the driver ID. */
                err = CRYPTODEV_NEWSESSION(cap->cc_dev, &lid, cri);
                if (err == 0) {
                        (*sid) = (cap->cc_flags & 0xff000000)
                               | (hid & 0x00ffffff);
                        (*sid) <<= 32;
                        (*sid) |= (lid & 0xffffffff);
                        cap->cc_sessions++;
                }
        } else
                err = EINVAL;
        CRYPTO_DRIVER_UNLOCK();
        return err;
}

static void
crypto_remove(struct cryptocap *cap)
{

        KKASSERT(lockstatus(&crypto_drivers_lock, curthread) != 0);
        if (cap->cc_sessions == 0 && cap->cc_koperations == 0)
                bzero(cap, sizeof(*cap));
}

/*
 * Delete an existing session (or a reserved session on an unregistered
 * driver).
 */
int
crypto_freesession(u_int64_t sid)
{
        struct cryptocap *cap;
        u_int32_t hid;
        int err;

        CRYPTO_DRIVER_LOCK();

        if (crypto_drivers == NULL) {
                err = EINVAL;
                goto done;
        }

        /* Determine two IDs. */
        hid = CRYPTO_SESID2HID(sid);

        if (hid >= crypto_drivers_num) {
                err = ENOENT;
                goto done;
        }
        cap = &crypto_drivers[hid];

        if (cap->cc_sessions)
                cap->cc_sessions--;

        /* Call the driver cleanup routine, if available. */
        err = CRYPTODEV_FREESESSION(cap->cc_dev, sid);

        if (cap->cc_flags & CRYPTOCAP_F_CLEANUP)
                crypto_remove(cap);

done:
        CRYPTO_DRIVER_UNLOCK();
        return err;
}

/*
 * Return an unused driver id.  Used by drivers prior to registering
 * support for the algorithms they handle.
 */
int32_t
crypto_get_driverid(device_t dev, int flags)
{
        struct cryptocap *newdrv;
        int i;

        if ((flags & (CRYPTOCAP_F_HARDWARE | CRYPTOCAP_F_SOFTWARE)) == 0) {
                kprintf("%s: no flags specified when registering driver\n",
                    device_get_nameunit(dev));
                return -1;
        }

        CRYPTO_DRIVER_LOCK();

        for (i = 0; i < crypto_drivers_num; i++) {
                if (crypto_drivers[i].cc_dev == NULL &&
                    (crypto_drivers[i].cc_flags & CRYPTOCAP_F_CLEANUP) == 0) {
                        break;
                }
        }

        /* Out of entries, allocate some more. */
        if (i == crypto_drivers_num) {
                /* Be careful about wrap-around. */
                if (2 * crypto_drivers_num <= crypto_drivers_num) {
                        CRYPTO_DRIVER_UNLOCK();
                        kprintf("crypto: driver count wraparound!\n");
                        return -1;
                }

                newdrv = kmalloc(2 * crypto_drivers_num *
                    sizeof(struct cryptocap), M_CRYPTO_DATA, M_NOWAIT|M_ZERO);
                if (newdrv == NULL) {
                        CRYPTO_DRIVER_UNLOCK();
                        kprintf("crypto: no space to expand driver table!\n");
                        return -1;
                }

                bcopy(crypto_drivers, newdrv,
                    crypto_drivers_num * sizeof(struct cryptocap));

                crypto_drivers_num *= 2;

                kfree(crypto_drivers, M_CRYPTO_DATA);
                crypto_drivers = newdrv;
        }

        /* NB: state is zero'd on free */
        crypto_drivers[i].cc_sessions = 1;      /* Mark */
        crypto_drivers[i].cc_dev = dev;
        crypto_drivers[i].cc_flags = flags;
        if (bootverbose)
                kprintf("crypto: assign %s driver id %u, flags %u\n",
                    device_get_nameunit(dev), i, flags);

        CRYPTO_DRIVER_UNLOCK();

        return i;
}

/*
 * Lookup a driver by name.  We match against the full device
 * name and unit, and against just the name.  The latter gives
 * us a simple widlcarding by device name.  On success return the
 * driver/hardware identifier; otherwise return -1.
 */
int
crypto_find_driver(const char *match)
{
        int i, len = strlen(match);

        CRYPTO_DRIVER_LOCK();
        for (i = 0; i < crypto_drivers_num; i++) {
                device_t dev = crypto_drivers[i].cc_dev;
                if (dev == NULL ||
                    (crypto_drivers[i].cc_flags & CRYPTOCAP_F_CLEANUP))
                        continue;
                if (strncmp(match, device_get_nameunit(dev), len) == 0 ||
                    strncmp(match, device_get_name(dev), len) == 0)
                        break;
        }
        CRYPTO_DRIVER_UNLOCK();
        return i < crypto_drivers_num ? i : -1;
}

/*
 * Return the device_t for the specified driver or NULL
 * if the driver identifier is invalid.
 */
device_t
crypto_find_device_byhid(int hid)
{
        struct cryptocap *cap = crypto_checkdriver(hid);
        return cap != NULL ? cap->cc_dev : NULL;
}

/*
 * Return the device/driver capabilities.
 */
int
crypto_getcaps(int hid)
{
        struct cryptocap *cap = crypto_checkdriver(hid);
        return cap != NULL ? cap->cc_flags : 0;
}

/*
 * Register support for a key-related algorithm.  This routine
 * is called once for each algorithm supported a driver.
 */
int
crypto_kregister(u_int32_t driverid, int kalg, u_int32_t flags)
{
        struct cryptocap *cap;
        int err;

        CRYPTO_DRIVER_LOCK();

        cap = crypto_checkdriver(driverid);
        if (cap != NULL &&
            (CRK_ALGORITM_MIN <= kalg && kalg <= CRK_ALGORITHM_MAX)) {
                /*
                 * XXX Do some performance testing to determine placing.
                 * XXX We probably need an auxiliary data structure that
                 * XXX describes relative performances.
                 */

                cap->cc_kalg[kalg] = flags | CRYPTO_ALG_FLAG_SUPPORTED;
                if (bootverbose)
                        kprintf("crypto: %s registers key alg %u flags %u\n"
                                , device_get_nameunit(cap->cc_dev)
                                , kalg
                                , flags
                        );

                err = 0;
        } else
                err = EINVAL;

        CRYPTO_DRIVER_UNLOCK();
        return err;
}

/*
 * Register support for a non-key-related algorithm.  This routine
 * is called once for each such algorithm supported by a driver.
 */
int
crypto_register(u_int32_t driverid, int alg, u_int16_t maxoplen,
    u_int32_t flags)
{
        struct cryptocap *cap;
        int err;

        CRYPTO_DRIVER_LOCK();

        cap = crypto_checkdriver(driverid);
        /* NB: algorithms are in the range [1..max] */
        if (cap != NULL &&
            (CRYPTO_ALGORITHM_MIN <= alg && alg <= CRYPTO_ALGORITHM_MAX)) {
                /*
                 * XXX Do some performance testing to determine placing.
                 * XXX We probably need an auxiliary data structure that
                 * XXX describes relative performances.
                 */

                cap->cc_alg[alg] = flags | CRYPTO_ALG_FLAG_SUPPORTED;
                cap->cc_max_op_len[alg] = maxoplen;
                if (bootverbose)
                        kprintf("crypto: %s registers alg %u flags %u maxoplen %u\n"
                                , device_get_nameunit(cap->cc_dev)
                                , alg
                                , flags
                                , maxoplen
                        );
                cap->cc_sessions = 0;           /* Unmark */
                err = 0;
        } else
                err = EINVAL;

        CRYPTO_DRIVER_UNLOCK();
        return err;
}

static void
driver_finis(struct cryptocap *cap)
{
        u_int32_t ses, kops;

        CRYPTO_DRIVER_ASSERT();

        ses = cap->cc_sessions;
        kops = cap->cc_koperations;
        bzero(cap, sizeof(*cap));
        if (ses != 0 || kops != 0) {
                /*
                 * If there are pending sessions,
                 * just mark as invalid.
                 */
                cap->cc_flags |= CRYPTOCAP_F_CLEANUP;
                cap->cc_sessions = ses;
                cap->cc_koperations = kops;
        }
}

/*
 * Unregister a crypto driver. If there are pending sessions using it,
 * leave enough information around so that subsequent calls using those
 * sessions will correctly detect the driver has been unregistered and
 * reroute requests.
 */
int
crypto_unregister(u_int32_t driverid, int alg)
{
        struct cryptocap *cap;
        int i, err;

        CRYPTO_DRIVER_LOCK();
        cap = crypto_checkdriver(driverid);
        if (cap != NULL &&
            (CRYPTO_ALGORITHM_MIN <= alg && alg <= CRYPTO_ALGORITHM_MAX) &&
            cap->cc_alg[alg] != 0) {
                cap->cc_alg[alg] = 0;
                cap->cc_max_op_len[alg] = 0;

                /* Was this the last algorithm ? */
                for (i = 1; i <= CRYPTO_ALGORITHM_MAX; i++)
                        if (cap->cc_alg[i] != 0)
                                break;

                if (i == CRYPTO_ALGORITHM_MAX + 1)
                        driver_finis(cap);
                err = 0;
        } else
                err = EINVAL;
        CRYPTO_DRIVER_UNLOCK();

        return err;
}

/*
 * Unregister all algorithms associated with a crypto driver.
 * If there are pending sessions using it, leave enough information
 * around so that subsequent calls using those sessions will
 * correctly detect the driver has been unregistered and reroute
 * requests.
 */
int
crypto_unregister_all(u_int32_t driverid)
{
        struct cryptocap *cap;
        int err;

        CRYPTO_DRIVER_LOCK();
        cap = crypto_checkdriver(driverid);
        if (cap != NULL) {
                driver_finis(cap);
                err = 0;
        } else
                err = EINVAL;
        CRYPTO_DRIVER_UNLOCK();

        return err;
}

/*
 * Clear blockage on a driver.  The what parameter indicates whether
 * the driver is now ready for cryptop's and/or cryptokop's.
 */
int
crypto_unblock(u_int32_t driverid, int what)
{
        struct cryptocap *cap;
        int err;

        CRYPTO_Q_LOCK();
        cap = crypto_checkdriver(driverid);
        if (cap != NULL) {
                if (what & CRYPTO_SYMQ)
                        cap->cc_qblocked = 0;
                if (what & CRYPTO_ASYMQ)
                        cap->cc_kqblocked = 0;
                if (crp_sleep)
                        wakeup_one(&crp_q);
                err = 0;
        } else
                err = EINVAL;
        CRYPTO_Q_UNLOCK();

        return err;
}

/*
 * Add a crypto request to a queue, to be processed by the kernel thread.
 */
int
crypto_dispatch(struct cryptop *crp)
{
        struct cryptocap *cap;
        u_int32_t hid;
        int result;

        cryptostats.cs_ops++;

#ifdef CRYPTO_TIMING
        if (crypto_timing)
                nanouptime(&crp->crp_tstamp);
#endif

        hid = CRYPTO_SESID2HID(crp->crp_sid);

        if ((crp->crp_flags & CRYPTO_F_BATCH) == 0) {
                /*
                 * Caller marked the request to be processed
                 * immediately; dispatch it directly to the
                 * driver unless the driver is currently blocked.
                 */
                cap = crypto_checkdriver(hid);
                /* Driver cannot disappeared when there is an active session. */
                KASSERT(cap != NULL, ("%s: Driver disappeared.", __func__));
                if (!cap->cc_qblocked) {
                        result = crypto_invoke(cap, crp, 0);
                        if (result != ERESTART)
                                return (result);
                        /*
                         * The driver ran out of resources, put the request on
                         * the queue.
                         */
                }
        }
        CRYPTO_Q_LOCK();
        TAILQ_INSERT_TAIL(&crp_q, crp, crp_next);
        if (crp_sleep)
                wakeup_one(&crp_q);
        CRYPTO_Q_UNLOCK();
        return 0;
}

/*
 * Add an asymetric crypto request to a queue,
 * to be processed by the kernel thread.
 */
int
crypto_kdispatch(struct cryptkop *krp)
{
        int error;

        cryptostats.cs_kops++;

        error = crypto_kinvoke(krp, krp->krp_crid);
        if (error == ERESTART) {
                CRYPTO_Q_LOCK();
                TAILQ_INSERT_TAIL(&crp_kq, krp, krp_next);
                if (crp_sleep)
                        wakeup_one(&crp_q);
                CRYPTO_Q_UNLOCK();
                error = 0;
        }
        return error;
}

/*
 * Verify a driver is suitable for the specified operation.
 */
static __inline int
kdriver_suitable(const struct cryptocap *cap, const struct cryptkop *krp)
{
        return (cap->cc_kalg[krp->krp_op] & CRYPTO_ALG_FLAG_SUPPORTED) != 0;
}

/*
 * Select a driver for an asym operation.  The driver must
 * support the necessary algorithm.  The caller can constrain
 * which device is selected with the flags parameter.  The
 * algorithm we use here is pretty stupid; just use the first
 * driver that supports the algorithms we need. If there are
 * multiple suitable drivers we choose the driver with the
 * fewest active operations.  We prefer hardware-backed
 * drivers to software ones when either may be used.
 */
static struct cryptocap *
crypto_select_kdriver(const struct cryptkop *krp, int flags)
{
        struct cryptocap *cap, *best, *blocked;
        int match, hid;

        CRYPTO_DRIVER_ASSERT();

        /*
         * Look first for hardware crypto devices if permitted.
         */
        if (flags & CRYPTOCAP_F_HARDWARE)
                match = CRYPTOCAP_F_HARDWARE;
        else
                match = CRYPTOCAP_F_SOFTWARE;
        best = NULL;
        blocked = NULL;
again:
        for (hid = 0; hid < crypto_drivers_num; hid++) {
                cap = &crypto_drivers[hid];
                /*
                 * If it's not initialized, is in the process of
                 * going away, or is not appropriate (hardware
                 * or software based on match), then skip.
                 */
                if (cap->cc_dev == NULL ||
                    (cap->cc_flags & CRYPTOCAP_F_CLEANUP) ||
                    (cap->cc_flags & match) == 0)
                        continue;

                /* verify all the algorithms are supported. */
                if (kdriver_suitable(cap, krp)) {
                        if (best == NULL ||
                            cap->cc_koperations < best->cc_koperations)
                                best = cap;
                }
        }
        if (best != NULL)
                return best;
        if (match == CRYPTOCAP_F_HARDWARE && (flags & CRYPTOCAP_F_SOFTWARE)) {
                /* sort of an Algol 68-style for loop */
                match = CRYPTOCAP_F_SOFTWARE;
                goto again;
        }
        return best;
}

/*
 * Dispatch an assymetric crypto request.
 */
static int
crypto_kinvoke(struct cryptkop *krp, int crid)
{
        struct cryptocap *cap = NULL;
        int error;

        KASSERT(krp != NULL, ("%s: krp == NULL", __func__));
        KASSERT(krp->krp_callback != NULL,
            ("%s: krp->crp_callback == NULL", __func__));

        CRYPTO_DRIVER_LOCK();
        if ((crid & (CRYPTOCAP_F_HARDWARE | CRYPTOCAP_F_SOFTWARE)) == 0) {
                cap = crypto_checkdriver(crid);
                if (cap != NULL) {
                        /*
                         * Driver present, it must support the necessary
                         * algorithm and, if s/w drivers are excluded,
                         * it must be registered as hardware-backed.
                         */
                        if (!kdriver_suitable(cap, krp) ||
                            (!crypto_devallowsoft &&
                             (cap->cc_flags & CRYPTOCAP_F_HARDWARE) == 0))
                                cap = NULL;
                }
        } else {
                /*
                 * No requested driver; select based on crid flags.
                 */
                if (!crypto_devallowsoft)       /* NB: disallow s/w drivers */
                        crid &= ~CRYPTOCAP_F_SOFTWARE;
                cap = crypto_select_kdriver(krp, crid);
        }
        if (cap != NULL && !cap->cc_kqblocked) {
                krp->krp_hid = cap - crypto_drivers;
                cap->cc_koperations++;
                CRYPTO_DRIVER_UNLOCK();
                error = CRYPTODEV_KPROCESS(cap->cc_dev, krp, 0);
                CRYPTO_DRIVER_LOCK();
                if (error == ERESTART) {
                        cap->cc_koperations--;
                        CRYPTO_DRIVER_UNLOCK();
                        return (error);
                }
        } else {
                /*
                 * NB: cap is !NULL if device is blocked; in
                 *     that case return ERESTART so the operation
                 *     is resubmitted if possible.
                 */
                error = (cap == NULL) ? ENODEV : ERESTART;
        }
        CRYPTO_DRIVER_UNLOCK();

        if (error) {
                krp->krp_status = error;
                crypto_kdone(krp);
        }
        return 0;
}

#ifdef CRYPTO_TIMING
static void
crypto_tstat(struct cryptotstat *ts, struct timespec *tv)
{
        struct timespec now, t;

        nanouptime(&now);
        t.tv_sec = now.tv_sec - tv->tv_sec;
        t.tv_nsec = now.tv_nsec - tv->tv_nsec;
        if (t.tv_nsec < 0) {
                t.tv_sec--;
                t.tv_nsec += 1000000000;
        }
        timespecadd(&ts->acc, &t);
        if (timespeccmp(&t, &ts->min, <))
                ts->min = t;
        if (timespeccmp(&t, &ts->max, >))
                ts->max = t;
        ts->count++;

        *tv = now;
}
#endif

/*
 * Dispatch a crypto request to the appropriate crypto devices.
 */
static int
crypto_invoke(struct cryptocap *cap, struct cryptop *crp, int hint)
{

        KASSERT(crp != NULL, ("%s: crp == NULL", __func__));
        KASSERT(crp->crp_callback != NULL,
            ("%s: crp->crp_callback == NULL", __func__));
        KASSERT(crp->crp_desc != NULL, ("%s: crp->crp_desc == NULL", __func__));

#ifdef CRYPTO_TIMING
        if (crypto_timing)
                crypto_tstat(&cryptostats.cs_invoke, &crp->crp_tstamp);
#endif
        if (cap->cc_flags & CRYPTOCAP_F_CLEANUP) {
                struct cryptodesc *crd;
                u_int64_t nid;

                /*
                 * Driver has unregistered; migrate the session and return
                 * an error to the caller so they'll resubmit the op.
                 *
                 * XXX: What if there are more already queued requests for this
                 *      session?
                 */
                crypto_freesession(crp->crp_sid);

                for (crd = crp->crp_desc; crd->crd_next; crd = crd->crd_next)
                        crd->CRD_INI.cri_next = &(crd->crd_next->CRD_INI);

                /* XXX propagate flags from initial session? */
                if (crypto_newsession(&nid, &(crp->crp_desc->CRD_INI),
                    CRYPTOCAP_F_HARDWARE | CRYPTOCAP_F_SOFTWARE) == 0)
                        crp->crp_sid = nid;

                crp->crp_etype = EAGAIN;
                crypto_done(crp);
                return 0;
        } else {
                /*
                 * Invoke the driver to process the request.
                 */
                return CRYPTODEV_PROCESS(cap->cc_dev, crp, hint);
        }
}

/*
 * Release a set of crypto descriptors.
 */
void
crypto_freereq(struct cryptop *crp)
{
        struct cryptodesc *crd;

        if (crp == NULL)
                return;

#ifdef DIAGNOSTIC
        {
                struct cryptop *crp2;

                CRYPTO_Q_LOCK();
                TAILQ_FOREACH(crp2, &crp_q, crp_next) {
                        KASSERT(crp2 != crp,
                            ("Freeing cryptop from the crypto queue (%p).",
                            crp));
                }
                CRYPTO_Q_UNLOCK();
                CRYPTO_RETQ_LOCK();
                TAILQ_FOREACH(crp2, &crp_ret_q, crp_next) {
                        KASSERT(crp2 != crp,
                            ("Freeing cryptop from the return queue (%p).",
                            crp));
                }
                CRYPTO_RETQ_UNLOCK();
        }
#endif

        while ((crd = crp->crp_desc) != NULL) {
                crp->crp_desc = crd->crd_next;
                zfree(cryptodesc_zone, crd);
        }
        zfree(cryptop_zone, crp);
}

/*
 * Acquire a set of crypto descriptors.
 */
struct cryptop *
crypto_getreq(int num)
{
        struct cryptodesc *crd;
        struct cryptop *crp;

        crp = zalloc(cryptop_zone);
        if (crp != NULL) {
                bzero(crp, sizeof (*crp));
                while (num--) {
                        crd = zalloc(cryptodesc_zone);
                        if (crd == NULL) {
                                crypto_freereq(crp);
                                return NULL;
                        }
                        bzero(crd, sizeof (*crd));

                        crd->crd_next = crp->crp_desc;
                        crp->crp_desc = crd;
                }
        }
        return crp;
}

/*
 * Invoke the callback on behalf of the driver.
 */
void
crypto_done(struct cryptop *crp)
{
        KASSERT((crp->crp_flags & CRYPTO_F_DONE) == 0,
                ("crypto_done: op already done, flags 0x%x", crp->crp_flags));
        crp->crp_flags |= CRYPTO_F_DONE;
        if (crp->crp_etype != 0)
                cryptostats.cs_errs++;
#ifdef CRYPTO_TIMING
        if (crypto_timing)
                crypto_tstat(&cryptostats.cs_done, &crp->crp_tstamp);
#endif
        /*
         * CBIMM means unconditionally do the callback immediately;
         * CBIFSYNC means do the callback immediately only if the
         * operation was done synchronously.  Both are used to avoid
         * doing extraneous context switches; the latter is mostly
         * used with the software crypto driver.
         */
        if ((crp->crp_flags & CRYPTO_F_CBIMM) ||
            ((crp->crp_flags & CRYPTO_F_CBIFSYNC) &&
             (CRYPTO_SESID2CAPS(crp->crp_sid) & CRYPTOCAP_F_SYNC))) {
                /*
                 * Do the callback directly.  This is ok when the
                 * callback routine does very little (e.g. the
                 * /dev/crypto callback method just does a wakeup).
                 */
#ifdef CRYPTO_TIMING
                if (crypto_timing) {
                        /*
                         * NB: We must copy the timestamp before
                         * doing the callback as the cryptop is
                         * likely to be reclaimed.
                         */
                        struct timespec t = crp->crp_tstamp;
                        crypto_tstat(&cryptostats.cs_cb, &t);
                        crp->crp_callback(crp);
                        crypto_tstat(&cryptostats.cs_finis, &t);
                } else
#endif
                        crp->crp_callback(crp);
        } else {
                /*
                 * Normal case; queue the callback for the thread.
                 */
                CRYPTO_RETQ_LOCK();
                if (CRYPTO_RETQ_EMPTY())
                        wakeup_one(&crp_ret_q); /* shared wait channel */
                TAILQ_INSERT_TAIL(&crp_ret_q, crp, crp_next);
                CRYPTO_RETQ_UNLOCK();
        }
}

/*
 * Invoke the callback on behalf of the driver.
 */
void
crypto_kdone(struct cryptkop *krp)
{
        struct cryptocap *cap;

        if (krp->krp_status != 0)
                cryptostats.cs_kerrs++;
        CRYPTO_DRIVER_LOCK();
        /* XXX: What if driver is loaded in the meantime? */
        if (krp->krp_hid < crypto_drivers_num) {
                cap = &crypto_drivers[krp->krp_hid];
                cap->cc_koperations--;
                KASSERT(cap->cc_koperations >= 0, ("cc_koperations < 0"));
                if (cap->cc_flags & CRYPTOCAP_F_CLEANUP)
                        crypto_remove(cap);
        }
        CRYPTO_DRIVER_UNLOCK();
        CRYPTO_RETQ_LOCK();
        if (CRYPTO_RETQ_EMPTY())
                wakeup_one(&crp_ret_q);         /* shared wait channel */
        TAILQ_INSERT_TAIL(&crp_ret_kq, krp, krp_next);
        CRYPTO_RETQ_UNLOCK();
}

int
crypto_getfeat(int *featp)
{
        int hid, kalg, feat = 0;

        CRYPTO_DRIVER_LOCK();
        for (hid = 0; hid < crypto_drivers_num; hid++) {
                const struct cryptocap *cap = &crypto_drivers[hid];

                if ((cap->cc_flags & CRYPTOCAP_F_SOFTWARE) &&
                    !crypto_devallowsoft) {
                        continue;
                }
                for (kalg = 0; kalg < CRK_ALGORITHM_MAX; kalg++)
                        if (cap->cc_kalg[kalg] & CRYPTO_ALG_FLAG_SUPPORTED)
                                feat |=  1 << kalg;
        }
        CRYPTO_DRIVER_UNLOCK();
        *featp = feat;
        return (0);
}

/*
 * Terminate a thread at module unload.  The process that
 * initiated this is waiting for us to signal that we're gone;
 * wake it up and exit.  We use the driver table lock to insure
 * we don't do the wakeup before they're waiting.  There is no
 * race here because the waiter sleeps on the proc lock for the
 * thread so it gets notified at the right time because of an
 * extra wakeup that's done in exit1().
 */
static void
crypto_finis(void *chan)
{
        CRYPTO_DRIVER_LOCK();
        wakeup_one(chan);
        CRYPTO_DRIVER_UNLOCK();
        kthread_exit();
}

/*
 * Crypto thread, dispatches crypto requests.
 */
static void
crypto_proc(void)
{
        struct cryptop *crp, *submit;
        struct cryptkop *krp;
        struct cryptocap *cap;
        u_int32_t hid;
        int result, hint;

        CRYPTO_Q_LOCK();
        for (;;) {
                /*
                 * Find the first element in the queue that can be
                 * processed and look-ahead to see if multiple ops
                 * are ready for the same driver.
                 */
                submit = NULL;
                hint = 0;
                TAILQ_FOREACH(crp, &crp_q, crp_next) {
                        hid = CRYPTO_SESID2HID(crp->crp_sid);
                        cap = crypto_checkdriver(hid);
                        /*
                         * Driver cannot disappeared when there is an active
                         * session.
                         */
                        KASSERT(cap != NULL, ("%s:%u Driver disappeared.",
                            __func__, __LINE__));
                        if (cap == NULL || cap->cc_dev == NULL) {
                                /* Op needs to be migrated, process it. */
                                if (submit == NULL)
                                        submit = crp;
                                break;
                        }
                        if (!cap->cc_qblocked) {
                                if (submit != NULL) {
                                        /*
                                         * We stop on finding another op,
                                         * regardless whether its for the same
                                         * driver or not.  We could keep
                                         * searching the queue but it might be
                                         * better to just use a per-driver
                                         * queue instead.
                                         */
                                        if (CRYPTO_SESID2HID(submit->crp_sid) == hid)
                                                hint = CRYPTO_HINT_MORE;
                                        break;
                                } else {
                                        submit = crp;
                                        if ((submit->crp_flags & CRYPTO_F_BATCH) == 0)
                                                break;
                                        /* keep scanning for more are q'd */
                                }
                        }
                }
                if (submit != NULL) {
                        TAILQ_REMOVE(&crp_q, submit, crp_next);
                        hid = CRYPTO_SESID2HID(submit->crp_sid);
                        cap = crypto_checkdriver(hid);
                        KASSERT(cap != NULL, ("%s:%u Driver disappeared.",
                            __func__, __LINE__));
                        result = crypto_invoke(cap, submit, hint);
                        if (result == ERESTART) {
                                /*
                                 * The driver ran out of resources, mark the
                                 * driver ``blocked'' for cryptop's and put
                                 * the request back in the queue.  It would
                                 * best to put the request back where we got
                                 * it but that's hard so for now we put it
                                 * at the front.  This should be ok; putting
                                 * it at the end does not work.
                                 */
                                /* XXX validate sid again? */
                                crypto_drivers[CRYPTO_SESID2HID(submit->crp_sid)].cc_qblocked = 1;
                                TAILQ_INSERT_HEAD(&crp_q, submit, crp_next);
                                cryptostats.cs_blocks++;
                        }
                }

                /* As above, but for key ops */
                TAILQ_FOREACH(krp, &crp_kq, krp_next) {
                        cap = crypto_checkdriver(krp->krp_hid);
                        if (cap == NULL || cap->cc_dev == NULL) {
                                /*
                                 * Operation needs to be migrated, invalidate
                                 * the assigned device so it will reselect a
                                 * new one below.  Propagate the original
                                 * crid selection flags if supplied.
                                 */
                                krp->krp_hid = krp->krp_crid &
                                    (CRYPTOCAP_F_SOFTWARE|CRYPTOCAP_F_HARDWARE);
                                if (krp->krp_hid == 0)
                                        krp->krp_hid =
                                    CRYPTOCAP_F_SOFTWARE|CRYPTOCAP_F_HARDWARE;
                                break;
                        }
                        if (!cap->cc_kqblocked)
                                break;
                }
                if (krp != NULL) {
                        TAILQ_REMOVE(&crp_kq, krp, krp_next);
                        result = crypto_kinvoke(krp, krp->krp_hid);
                        if (result == ERESTART) {
                                /*
                                 * The driver ran out of resources, mark the
                                 * driver ``blocked'' for cryptkop's and put
                                 * the request back in the queue.  It would
                                 * best to put the request back where we got
                                 * it but that's hard so for now we put it
                                 * at the front.  This should be ok; putting
                                 * it at the end does not work.
                                 */
                                /* XXX validate sid again? */
                                crypto_drivers[krp->krp_hid].cc_kqblocked = 1;
                                TAILQ_INSERT_HEAD(&crp_kq, krp, krp_next);
                                cryptostats.cs_kblocks++;
                        }
                }

                if (submit == NULL && krp == NULL) {
                        /*
                         * Nothing more to be processed.  Sleep until we're
                         * woken because there are more ops to process.
                         * This happens either by submission or by a driver
                         * becoming unblocked and notifying us through
                         * crypto_unblock.  Note that when we wakeup we
                         * start processing each queue again from the
                         * front. It's not clear that it's important to
                         * preserve this ordering since ops may finish
                         * out of order if dispatched to different devices
                         * and some become blocked while others do not.
                         */
                        crp_sleep = 1;
                        lksleep (&crp_q, &crypto_q_lock, 0, "crypto_wait", 0);
                        crp_sleep = 0;
                        if (cryptothread == NULL)
                                break;
                        cryptostats.cs_intrs++;
                }
        }
        CRYPTO_Q_UNLOCK();

        crypto_finis(&crp_q);
}

/*
 * Crypto returns thread, does callbacks for processed crypto requests.
 * Callbacks are done here, rather than in the crypto drivers, because
 * callbacks typically are expensive and would slow interrupt handling.
 */
static void
crypto_ret_proc(void)
{
        struct cryptop *crpt;
        struct cryptkop *krpt;

        CRYPTO_RETQ_LOCK();
        for (;;) {
                /* Harvest return q's for completed ops */
                crpt = TAILQ_FIRST(&crp_ret_q);
                if (crpt != NULL)
                        TAILQ_REMOVE(&crp_ret_q, crpt, crp_next);

                krpt = TAILQ_FIRST(&crp_ret_kq);
                if (krpt != NULL)
                        TAILQ_REMOVE(&crp_ret_kq, krpt, krp_next);

                if (crpt != NULL || krpt != NULL) {
                        CRYPTO_RETQ_UNLOCK();
                        /*
                         * Run callbacks unlocked.
                         */
                        if (crpt != NULL) {
#ifdef CRYPTO_TIMING
                                if (crypto_timing) {
                                        /*
                                         * NB: We must copy the timestamp before
                                         * doing the callback as the cryptop is
                                         * likely to be reclaimed.
                                         */
                                        struct timespec t = crpt->crp_tstamp;
                                        crypto_tstat(&cryptostats.cs_cb, &t);
                                        crpt->crp_callback(crpt);
                                        crypto_tstat(&cryptostats.cs_finis, &t);
                                } else
#endif
                                        crpt->crp_callback(crpt);
                        }
                        if (krpt != NULL)
                                krpt->krp_callback(krpt);
                        CRYPTO_RETQ_LOCK();
                } else {
                        /*
                         * Nothing more to be processed.  Sleep until we're
                         * woken because there are more returns to process.
                         */
                        lksleep (&crp_ret_q, &crypto_ret_q_lock, 0, "crypto_ret_wait", 0);
                        if (cryptoretthread == NULL) {
                                break;
                        }
                        cryptostats.cs_rets++;
                }
        }
        CRYPTO_RETQ_UNLOCK();

        crypto_finis(&crp_ret_q);
}

#ifdef DDB
static void
db_show_drivers(void)
{
        int hid;

        db_printf("%12s %4s %4s %8s %2s %2s\n"
                , "Device"
                , "Ses"
                , "Kops"
                , "Flags"
                , "QB"
                , "KB"
        );
        for (hid = 0; hid < crypto_drivers_num; hid++) {
                const struct cryptocap *cap = &crypto_drivers[hid];
                if (cap->cc_dev == NULL)
                        continue;
                db_printf("%-12s %4u %4u %08x %2u %2u\n"
                    , device_get_nameunit(cap->cc_dev)
                    , cap->cc_sessions
                    , cap->cc_koperations
                    , cap->cc_flags
                    , cap->cc_qblocked
                    , cap->cc_kqblocked
                );
        }
}

DB_SHOW_COMMAND(crypto, db_show_crypto)
{
        struct cryptop *crp;

        db_show_drivers();
        db_printf("\n");

        db_printf("%4s %8s %4s %4s %4s %4s %8s %8s\n",
            "HID", "Caps", "Ilen", "Olen", "Etype", "Flags",
            "Desc", "Callback");
        TAILQ_FOREACH(crp, &crp_q, crp_next) {
                db_printf("%4u %08x %4u %4u %4u %04x %8p %8p\n"
                    , (int) CRYPTO_SESID2HID(crp->crp_sid)
                    , (int) CRYPTO_SESID2CAPS(crp->crp_sid)
                    , crp->crp_ilen, crp->crp_olen
                    , crp->crp_etype
                    , crp->crp_flags
                    , crp->crp_desc
                    , crp->crp_callback
                );
        }
        if (!TAILQ_EMPTY(&crp_ret_q)) {
                db_printf("\n%4s %4s %4s %8s\n",
                    "HID", "Etype", "Flags", "Callback");
                TAILQ_FOREACH(crp, &crp_ret_q, crp_next) {
                        db_printf("%4u %4u %04x %8p\n"
                            , (int) CRYPTO_SESID2HID(crp->crp_sid)
                            , crp->crp_etype
                            , crp->crp_flags
                            , crp->crp_callback
                        );
                }
        }
}

DB_SHOW_COMMAND(kcrypto, db_show_kcrypto)
{
        struct cryptkop *krp;

        db_show_drivers();
        db_printf("\n");

        db_printf("%4s %5s %4s %4s %8s %4s %8s\n",
            "Op", "Status", "#IP", "#OP", "CRID", "HID", "Callback");
        TAILQ_FOREACH(krp, &crp_kq, krp_next) {
                db_printf("%4u %5u %4u %4u %08x %4u %8p\n"
                    , krp->krp_op
                    , krp->krp_status
                    , krp->krp_iparams, krp->krp_oparams
                    , krp->krp_crid, krp->krp_hid
                    , krp->krp_callback
                );
        }
        if (!TAILQ_EMPTY(&crp_ret_q)) {
                db_printf("%4s %5s %8s %4s %8s\n",
                    "Op", "Status", "CRID", "HID", "Callback");
                TAILQ_FOREACH(krp, &crp_ret_kq, krp_next) {
                        db_printf("%4u %5u %08x %4u %8p\n"
                            , krp->krp_op
                            , krp->krp_status
                            , krp->krp_crid, krp->krp_hid
                            , krp->krp_callback
                        );
                }
        }
}
#endif

int crypto_modevent(module_t mod, int type, void *unused);

/*
 * Initialization code, both for static and dynamic loading.
 * Note this is not invoked with the usual MODULE_DECLARE
 * mechanism but instead is listed as a dependency by the
 * cryptosoft driver.  This guarantees proper ordering of
 * calls on module load/unload.
 */
int
crypto_modevent(module_t mod, int type, void *unused)
{
        int error = EINVAL;

        switch (type) {
        case MOD_LOAD:
                error = crypto_init();
                if (error == 0 && bootverbose)
                        kprintf("crypto: <crypto core>\n");
                break;
        case MOD_UNLOAD:
                /*XXX disallow if active sessions */
                error = 0;
                crypto_destroy();
                return 0;
        }
        return error;
}
MODULE_VERSION(crypto, 1);
MODULE_DEPEND(crypto, zlib, 1, 1, 1);