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

/*      $FreeBSD: src/sys/opencrypto/crypto.c,v 1.4.2.7 2003/06/03 00:09:02 sam Exp $   */
/*      $DragonFly: src/sys/opencrypto/crypto.c,v 1.7 2005/02/01 22:41:27 dillon Exp $  */
/*      $OpenBSD: crypto.c,v 1.38 2002/06/11 11:14:29 beck Exp $        */
/*
 * 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 cryptop timing stuff */

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

#include <sys/interrupt.h>
#include <machine/ipl.h>

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

#define SESID2HID(sid)  (((sid) >> 32) & 0xffffffff)

/*
 * 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 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.
 */
static  TAILQ_HEAD(,cryptop) crp_q;             /* request queues */
static  TAILQ_HEAD(,cryptkop) crp_kq;

/*
 * 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).  See below
 * for how synchronization is handled.
 */
static  TAILQ_HEAD(,cryptop) crp_ret_q;         /* callback queues */
static  TAILQ_HEAD(,cryptkop) 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_usercrypto = 1;          /* userland may open /dev/crypto */
SYSCTL_INT(_kern, OID_AUTO, usercrypto, CTLFLAG_RW,
           &crypto_usercrypto, 0,
           "Enable/disable user-mode access to crypto support");
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");

/*
 * Synchronization: read carefully, this is non-trivial.
 *
 * Crypto requests are submitted via crypto_dispatch.  Typically
 * these come in from network protocols at spl0 (output path) or
 * splnet (input path).
 *
 * Requests are typically passed on the driver directly, but they
 * may also be queued for processing by a software interrupt thread,
 * cryptointr, that runs at splsoftcrypto.  This thread dispatches 
 * the requests to crypto drivers (h/w or s/w) who call crypto_done
 * when a request is complete.  Hardware crypto drivers are assumed
 * to register their IRQ's as network devices so their interrupt handlers
 * and subsequent "done callbacks" happen at splimp.
 *
 * Completed crypto ops are queued for a separate kernel thread that
 * handles the callbacks at spl0.  This decoupling insures the crypto
 * driver interrupt service routine is not delayed while the callback
 * takes place and that callbacks are delivered after a context switch
 * (as opposed to a software interrupt that clients must block).
 *
 * This scheme is not intended for SMP machines.
 */ 
static  void cryptointr(void *dummy);   /* swi thread to dispatch ops */
static  void cryptoret(void);           /* kernel thread for callbacks*/
static  struct thread *cryptothread;
static  void crypto_destroy(void);
static  int crypto_invoke(struct cryptop *crp, int hint);
static  int crypto_kinvoke(struct cryptkop *krp, int hint);

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;

        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) {
                printf("crypto_init: cannot setup crypto zones\n");
                return ENOMEM;
        }

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

        TAILQ_INIT(&crp_q);
        TAILQ_INIT(&crp_kq);

        TAILQ_INIT(&crp_ret_q);
        TAILQ_INIT(&crp_ret_kq);

        register_swi(SWI_CRYPTO, cryptointr, NULL, "swi_crypto", NULL);
        error = kthread_create((void (*)(void *)) cryptoret, NULL,
                    &cryptothread, "cryptoret");
        if (error) {
                printf("crypto_init: cannot start cryptoret thread; error %d",
                        error);
                crypto_destroy();
        }
        return error;
}

static void
crypto_destroy(void)
{
        /* XXX no wait to reclaim zones */
        if (crypto_drivers != NULL)
                free(crypto_drivers, M_CRYPTO_DATA);
        unregister_swi(SWI_CRYPTO, cryptointr);
}

/*
 * Initialization code, both for static and dynamic loading.
 */
static 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)
                        printf("crypto: <crypto core>\n");
                break;
        case MOD_UNLOAD:
                /*XXX disallow if active sessions */
                error = 0;
                crypto_destroy();
                break;
        }
        return error;
}

static moduledata_t crypto_mod = {
        "crypto",
        crypto_modevent,
        0
};
MODULE_VERSION(crypto, 1);
DECLARE_MODULE(crypto, crypto_mod, SI_SUB_DRIVERS, SI_ORDER_FIRST);

/*
 * Create a new session.
 */
int
crypto_newsession(u_int64_t *sid, struct cryptoini *cri, int hard)
{
        struct cryptoini *cr;
        u_int32_t hid, lid;
        int err = EINVAL;
        int s;

        s = splcrypto();

        if (crypto_drivers == NULL)
                goto done;

        /*
         * The algorithm we use here is pretty stupid; just use the
         * first driver that supports all the algorithms we need.
         *
         * XXX We need more smarts here (in real life too, but that's
         * XXX another story altogether).
         */

        for (hid = 0; hid < crypto_drivers_num; hid++) {
                /*
                 * If it's not initialized or has remaining sessions
                 * referencing it, skip.
                 */
                if (crypto_drivers[hid].cc_newsession == NULL ||
                    (crypto_drivers[hid].cc_flags & CRYPTOCAP_F_CLEANUP))
                        continue;

                /* Hardware required -- ignore software drivers. */
                if (hard > 0 &&
                    (crypto_drivers[hid].cc_flags & CRYPTOCAP_F_SOFTWARE))
                        continue;
                /* Software required -- ignore hardware drivers. */
                if (hard < 0 &&
                    (crypto_drivers[hid].cc_flags & CRYPTOCAP_F_SOFTWARE) == 0)
                        continue;

                /* See if all the algorithms are supported. */
                for (cr = cri; cr; cr = cr->cri_next)
                        if (crypto_drivers[hid].cc_alg[cr->cri_alg] == 0)
                                break;

                if (cr == NULL) {
                        /* Ok, all algorithms are supported. */

                        /*
                         * Can't do everything in one session.
                         *
                         * XXX Fix this. We need to inject a "virtual" session layer right
                         * XXX about here.
                         */

                        /* Call the driver initialization routine. */
                        lid = hid;              /* Pass the driver ID. */
                        err = crypto_drivers[hid].cc_newsession(
                                        crypto_drivers[hid].cc_arg, &lid, cri);
                        if (err == 0) {
                                (*sid) = hid;
                                (*sid) <<= 32;
                                (*sid) |= (lid & 0xffffffff);
                                crypto_drivers[hid].cc_sessions++;
                        }
                        break;
                }
        }
done:
        splx(s);
        return err;
}

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

        s = splcrypto();

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

        /* Determine two IDs. */
        hid = SESID2HID(sid);

        if (hid >= crypto_drivers_num) {
                err = ENOENT;
                goto done;
        }

        if (crypto_drivers[hid].cc_sessions)
                crypto_drivers[hid].cc_sessions--;

        /* Call the driver cleanup routine, if available. */
        if (crypto_drivers[hid].cc_freesession)
                err = crypto_drivers[hid].cc_freesession(
                                crypto_drivers[hid].cc_arg, sid);
        else
                err = 0;

        /*
         * If this was the last session of a driver marked as invalid,
         * make the entry available for reuse.
         */
        if ((crypto_drivers[hid].cc_flags & CRYPTOCAP_F_CLEANUP) &&
            crypto_drivers[hid].cc_sessions == 0)
                bzero(&crypto_drivers[hid], sizeof(struct cryptocap));

done:
        splx(s);
        return err;
}

/*
 * Return an unused driver id.  Used by drivers prior to registering
 * support for the algorithms they handle.
 */
int32_t
crypto_get_driverid(u_int32_t flags)
{
        struct cryptocap *newdrv;
        int i, s;

        s = splcrypto();
        for (i = 0; i < crypto_drivers_num; i++)
                if (crypto_drivers[i].cc_process == NULL &&
                    (crypto_drivers[i].cc_flags & CRYPTOCAP_F_CLEANUP) == 0 &&
                    crypto_drivers[i].cc_sessions == 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) {
                        splx(s);
                        printf("crypto: driver count wraparound!\n");
                        return -1;
                }

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

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

                crypto_drivers_num *= 2;

                free(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_flags = flags;
        if (bootverbose)
                printf("crypto: assign driver %u, flags %u\n", i, flags);

        splx(s);

        return i;
}

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

/*
 * 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,
    int (*kprocess)(void*, struct cryptkop *, int),
    void *karg)
{
        int s;
        struct cryptocap *cap;
        int err;

        s = splcrypto();

        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)
                        printf("crypto: driver %u registers key alg %u flags %u\n"
                                , driverid
                                , kalg
                                , flags
                        );

                if (cap->cc_kprocess == NULL) {
                        cap->cc_karg = karg;
                        cap->cc_kprocess = kprocess;
                }
                err = 0;
        } else
                err = EINVAL;

        splx(s);
        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,
    int (*newses)(void*, u_int32_t*, struct cryptoini*),
    int (*freeses)(void*, u_int64_t),
    int (*process)(void*, struct cryptop *, int),
    void *arg)
{
        struct cryptocap *cap;
        int s, err;

        s = splcrypto();

        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)
                        printf("crypto: driver %u registers alg %u flags %u maxoplen %u\n"
                                , driverid
                                , alg
                                , flags
                                , maxoplen
                        );

                if (cap->cc_process == NULL) {
                        cap->cc_arg = arg;
                        cap->cc_newsession = newses;
                        cap->cc_process = process;
                        cap->cc_freesession = freeses;
                        cap->cc_sessions = 0;           /* Unmark */
                }
                err = 0;
        } else
                err = EINVAL;

        splx(s);
        return err;
}

/*
 * 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)
{
        int i, err, s = splcrypto();
        u_int32_t ses;
        struct cryptocap *cap;

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

        splx(s);
        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)
{
        int i, err, s = splcrypto();
        u_int32_t ses;
        struct cryptocap *cap;

        cap = crypto_checkdriver(driverid);
        if (cap != NULL) {
                for (i = CRYPTO_ALGORITHM_MIN; i <= CRYPTO_ALGORITHM_MAX; i++) {
                        cap->cc_alg[i] = 0;
                        cap->cc_max_op_len[i] = 0;
                }
                ses = cap->cc_sessions;
                bzero(cap, sizeof(struct cryptocap));
                if (ses != 0) {
                        /*
                         * If there are pending sessions, just mark as invalid.
                         */
                        cap->cc_flags |= CRYPTOCAP_F_CLEANUP;
                        cap->cc_sessions = ses;
                }
                err = 0;
        } else
                err = EINVAL;

        splx(s);
        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 needwakeup, err, s;

        s = splcrypto();
        cap = crypto_checkdriver(driverid);
        if (cap != NULL) {
                needwakeup = 0;
                if (what & CRYPTO_SYMQ) {
                        needwakeup |= cap->cc_qblocked;
                        cap->cc_qblocked = 0;
                }
                if (what & CRYPTO_ASYMQ) {
                        needwakeup |= cap->cc_kqblocked;
                        cap->cc_kqblocked = 0;
                }
                if (needwakeup)
                        setsoftcrypto();
                err = 0;
        } else
                err = EINVAL;
        splx(s);

        return err;
}

/*
 * Dispatch a crypto request to a driver or queue
 * it, to be processed by the kernel thread.
 */
int
crypto_dispatch(struct cryptop *crp)
{
        u_int32_t hid = SESID2HID(crp->crp_sid);
        int s, result;

        cryptostats.cs_ops++;

#ifdef CRYPTO_TIMING
        if (crypto_timing)
                nanouptime(&crp->crp_tstamp);
#endif
        s = splcrypto();
        if ((crp->crp_flags & CRYPTO_F_BATCH) == 0) {
                struct cryptocap *cap;
                /*
                 * Caller marked the request to be processed
                 * immediately; dispatch it directly to the
                 * driver unless the driver is currently blocked.
                 */
                cap = crypto_checkdriver(hid);
                if (cap && !cap->cc_qblocked) {
                        result = crypto_invoke(crp, 0);
                        if (result == ERESTART) {
                                /*
                                 * The driver ran out of resources, mark the
                                 * driver ``blocked'' for cryptop's and put
                                 * the op on the queue.
                                 */
                                crypto_drivers[hid].cc_qblocked = 1;
                                TAILQ_INSERT_HEAD(&crp_q, crp, crp_next);
                                cryptostats.cs_blocks++;
                                result = 0;
                        }
                } else {
                        /*
                         * The driver is blocked, just queue the op until
                         * it unblocks and the swi thread gets kicked.
                         */
                        TAILQ_INSERT_TAIL(&crp_q, crp, crp_next);
                        result = 0;
                }
        } else {
                int wasempty = TAILQ_EMPTY(&crp_q);
                /*
                 * Caller marked the request as ``ok to delay'';
                 * queue it for the swi thread.  This is desirable
                 * when the operation is low priority and/or suitable
                 * for batching.
                 */
                TAILQ_INSERT_TAIL(&crp_q, crp, crp_next);
                if (wasempty)
                        setsoftcrypto();
                result = 0;
        }
        splx(s);

        return result;
}

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

        cryptostats.cs_kops++;

        s = splcrypto();
        cap = crypto_checkdriver(krp->krp_hid);
        if (cap && !cap->cc_kqblocked) {
                result = crypto_kinvoke(krp, 0);
                if (result == ERESTART) {
                        /*
                         * The driver ran out of resources, mark the
                         * driver ``blocked'' for cryptop's and put
                         * the op on the queue.
                         */
                        crypto_drivers[krp->krp_hid].cc_kqblocked = 1;
                        TAILQ_INSERT_HEAD(&crp_kq, krp, krp_next);
                        cryptostats.cs_kblocks++;
                }
        } else {
                /*
                 * The driver is blocked, just queue the op until
                 * it unblocks and the swi thread gets kicked.
                 */
                TAILQ_INSERT_TAIL(&crp_kq, krp, krp_next);
                result = 0;
        }
        splx(s);

        return result;
}

/*
 * Dispatch an assymetric crypto request to the appropriate crypto devices.
 */
static int
crypto_kinvoke(struct cryptkop *krp, int hint)
{
        u_int32_t hid;
        int error;

        /* Sanity checks. */
        if (krp == NULL)
                return EINVAL;
        if (krp->krp_callback == NULL) {
                free(krp, M_XDATA);             /* XXX allocated in cryptodev */
                return EINVAL;
        }

        for (hid = 0; hid < crypto_drivers_num; hid++) {
                if ((crypto_drivers[hid].cc_flags & CRYPTOCAP_F_SOFTWARE) &&
                    !crypto_devallowsoft)
                        continue;
                if (crypto_drivers[hid].cc_kprocess == NULL)
                        continue;
                if ((crypto_drivers[hid].cc_kalg[krp->krp_op] &
                    CRYPTO_ALG_FLAG_SUPPORTED) == 0)
                        continue;
                break;
        }
        if (hid < crypto_drivers_num) {
                krp->krp_hid = hid;
                error = crypto_drivers[hid].cc_kprocess(
                                crypto_drivers[hid].cc_karg, krp, hint);
        } else
                error = ENODEV;

        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 cryptop *crp, int hint)
{
        u_int32_t hid;
        int (*process)(void*, struct cryptop *, int);

#ifdef CRYPTO_TIMING
        if (crypto_timing)
                crypto_tstat(&cryptostats.cs_invoke, &crp->crp_tstamp);
#endif
        /* Sanity checks. */
        if (crp == NULL)
                return EINVAL;
        if (crp->crp_callback == NULL) {
                crypto_freereq(crp);
                return EINVAL;
        }
        if (crp->crp_desc == NULL) {
                crp->crp_etype = EINVAL;
                crypto_done(crp);
                return 0;
        }

        hid = SESID2HID(crp->crp_sid);
        if (hid < crypto_drivers_num) {
                if (crypto_drivers[hid].cc_flags & CRYPTOCAP_F_CLEANUP)
                        crypto_freesession(crp->crp_sid);
                process = crypto_drivers[hid].cc_process;
        } else {
                process = NULL;
        }

        if (process == NULL) {
                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.
                 */
                for (crd = crp->crp_desc; crd->crd_next; crd = crd->crd_next)
                        crd->CRD_INI.cri_next = &(crd->crd_next->CRD_INI);

                if (crypto_newsession(&nid, &(crp->crp_desc->CRD_INI), 0) == 0)
                        crp->crp_sid = nid;

                crp->crp_etype = EAGAIN;
                crypto_done(crp);
                return 0;
        } else {
                /*
                 * Invoke the driver to process the request.
                 */
                return (*process)(crypto_drivers[hid].cc_arg, crp, hint);
        }
}

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

        if (crp) {
                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.  The descriptors are self contained
 * so no special spl protection is necessary.
 */
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);
                                crp = NULL;
                                break;
                        }
                        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
        if (crp->crp_flags & CRYPTO_F_CBIMM) {
                /*
                 * 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 {
                int s, wasempty;
                /*
                 * Normal case; queue the callback for the thread.
                 *
                 * The return queue is manipulated by the swi thread
                 * and, potentially, by crypto device drivers calling
                 * back to mark operations completed.  Thus we need
                 * to mask both while manipulating the return queue.
                 */
                s = splcrypto();
                wasempty = TAILQ_EMPTY(&crp_ret_q);
                TAILQ_INSERT_TAIL(&crp_ret_q, crp, crp_next);
                if (wasempty)
                        wakeup_one(&crp_ret_q);
                splx(s);
        }
}

/*
 * Invoke the callback on behalf of the driver.
 */
void
crypto_kdone(struct cryptkop *krp)
{
        int s, wasempty;

        if (krp->krp_status != 0)
                cryptostats.cs_kerrs++;
        /*
         * The return queue is manipulated by the swi thread
         * and, potentially, by crypto device drivers calling
         * back to mark operations completed.  Thus we need
         * to mask both while manipulating the return queue.
         */
        s = splcrypto();
        wasempty = TAILQ_EMPTY(&crp_ret_kq);
        TAILQ_INSERT_TAIL(&crp_ret_kq, krp, krp_next);
        if (wasempty)
                wakeup_one(&crp_ret_q);
        splx(s);
}

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

        if (!crypto_userasymcrypto)
                goto out;         

        for (hid = 0; hid < crypto_drivers_num; hid++) {
                if ((crypto_drivers[hid].cc_flags & CRYPTOCAP_F_SOFTWARE) &&
                    !crypto_devallowsoft) {
                        continue;
                }
                if (crypto_drivers[hid].cc_kprocess == NULL)
                        continue;
                for (kalg = 0; kalg < CRK_ALGORITHM_MAX; kalg++)
                        if ((crypto_drivers[hid].cc_kalg[kalg] &
                            CRYPTO_ALG_FLAG_SUPPORTED) != 0)
                                feat |=  1 << kalg;
        }
out:
        splx(s);
        *featp = feat;
        return (0);
}

/*
 * Software interrupt thread to dispatch crypto requests.
 */
static void
cryptointr(void *dummy)
{
        struct cryptop *crp, *submit;
        struct cryptkop *krp;
        struct cryptocap *cap;
        int result, hint, s;

        cryptostats.cs_intrs++;
        s = splcrypto();
        do {
                /*
                 * 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) {
                        u_int32_t hid = SESID2HID(crp->crp_sid);
                        cap = crypto_checkdriver(hid);
                        if (cap == NULL || cap->cc_process == 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 (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);
                        result = crypto_invoke(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[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_kprocess == NULL) {
                                /* Op needs to be migrated, process it. */
                                break;
                        }
                        if (!cap->cc_kqblocked)
                                break;
                }
                if (krp != NULL) {
                        TAILQ_REMOVE(&crp_kq, krp, krp_next);
                        result = crypto_kinvoke(krp, 0);
                        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++;
                        }
                }
        } while (submit != NULL || krp != NULL);
        splx(s);
}

/*
 * Kernel thread to do callbacks.
 */
static void
cryptoret(void)
{
        struct cryptop *crp;
        struct cryptkop *krp;
        int s;

        s = splcrypto();
        for (;;) {
                crp = TAILQ_FIRST(&crp_ret_q);
                if (crp != NULL)
                        TAILQ_REMOVE(&crp_ret_q, crp, crp_next);
                krp = TAILQ_FIRST(&crp_ret_kq);
                if (krp != NULL)
                        TAILQ_REMOVE(&crp_ret_kq, krp, krp_next);

                if (crp != NULL || krp != NULL) {
                        splx(s);                /* lower ipl for callbacks */
                        if (crp != 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 = 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);
                        }
                        if (krp != NULL)
                                krp->krp_callback(krp);
                        s  = splcrypto();
                } else {
                        (void) tsleep(&crp_ret_q, 0, "crypto_wait", 0);
                        cryptostats.cs_rets++;
                }
        }
}