crypto: Don't assert for empty output buffers.

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

/*-
 * Copyright (c) 2002-2006 Sam Leffler.  All rights reserved.
 * Copyright (c) 2021 The FreeBSD Foundation
 *
 * Portions of this software were developed by Ararat River
 * Consulting, LLC under sponsorship of the FreeBSD Foundation.
 *
 * 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.
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");

/*
 * 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.
 */

#include "opt_compat.h"
#include "opt_ddb.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/counter.h>
#include <sys/kernel.h>
#include <sys/kthread.h>
#include <sys/linker.h>
#include <sys/lock.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/proc.h>
#include <sys/refcount.h>
#include <sys/sdt.h>
#include <sys/smp.h>
#include <sys/sysctl.h>
#include <sys/taskqueue.h>
#include <sys/uio.h>

#include <ddb/ddb.h>

#include <machine/vmparam.h>
#include <vm/uma.h>

#include <crypto/intake.h>
#include <opencrypto/cryptodev.h>
#include <opencrypto/xform_auth.h>
#include <opencrypto/xform_enc.h>

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

#if defined(__i386__) || defined(__amd64__) || defined(__aarch64__)
#include <machine/pcb.h>
#endif

SDT_PROVIDER_DEFINE(opencrypto);

/*
 * Crypto drivers register themselves by allocating a slot in the
 * crypto_drivers table with crypto_get_driverid() and then registering
 * each asym algorithm they support with crypto_kregister().
 */
static  struct mtx crypto_drivers_mtx;          /* lock on driver table */
#define CRYPTO_DRIVER_LOCK()    mtx_lock(&crypto_drivers_mtx)
#define CRYPTO_DRIVER_UNLOCK()  mtx_unlock(&crypto_drivers_mtx)
#define CRYPTO_DRIVER_ASSERT()  mtx_assert(&crypto_drivers_mtx, MA_OWNED)

/*
 * 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;
        uint32_t        cc_hid;
        uint32_t        cc_sessions;            /* (d) # of sessions */
        uint32_t        cc_koperations;         /* (d) # os asym operations */
        uint8_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 */
        size_t          cc_session_size;
        volatile int    cc_refs;
};

static  struct cryptocap **crypto_drivers = NULL;
static  int crypto_drivers_size = 0;

struct crypto_session {
        struct cryptocap *cap;
        struct crypto_session_params csp;
        uint64_t id;
        /* Driver softc follows. */
};

/*
 * There are two queues for crypto requests; one for symmetric (e.g.
 * cipher) operations and one for asymmetric (e.g. MOD)operations.
 * A single mutex 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_q ,cryptop) crp_q;           /* request queues */
static  TAILQ_HEAD(,cryptkop) crp_kq;
static  struct mtx crypto_q_mtx;
#define CRYPTO_Q_LOCK()         mtx_lock(&crypto_q_mtx)
#define CRYPTO_Q_UNLOCK()       mtx_unlock(&crypto_q_mtx)

SYSCTL_NODE(_kern, OID_AUTO, crypto, CTLFLAG_RW, 0,
    "In-kernel cryptography");

/*
 * Taskqueue used to dispatch the crypto requests
 * that have the CRYPTO_F_ASYNC flag
 */
static struct taskqueue *crypto_tq;

/*
 * Crypto seq numbers are operated on with modular arithmetic
 */
#define CRYPTO_SEQ_GT(a,b)      ((int)((a)-(b)) > 0)

struct crypto_ret_worker {
        struct mtx crypto_ret_mtx;

        TAILQ_HEAD(,cryptop) crp_ordered_ret_q; /* ordered callback queue for symetric jobs */
        TAILQ_HEAD(,cryptop) crp_ret_q;         /* callback queue for symetric jobs */
        TAILQ_HEAD(,cryptkop) crp_ret_kq;       /* callback queue for asym jobs */

        uint32_t reorder_ops;           /* total ordered sym jobs received */
        uint32_t reorder_cur_seq;       /* current sym job dispatched */

        struct thread *td;
};
static struct crypto_ret_worker *crypto_ret_workers = NULL;

#define CRYPTO_RETW(i)          (&crypto_ret_workers[i])
#define CRYPTO_RETW_ID(w)       ((w) - crypto_ret_workers)
#define FOREACH_CRYPTO_RETW(w) \
        for (w = crypto_ret_workers; w < crypto_ret_workers + crypto_workers_num; ++w)

#define CRYPTO_RETW_LOCK(w)     mtx_lock(&w->crypto_ret_mtx)
#define CRYPTO_RETW_UNLOCK(w)   mtx_unlock(&w->crypto_ret_mtx)
#define CRYPTO_RETW_EMPTY(w) \
        (TAILQ_EMPTY(&w->crp_ret_q) && TAILQ_EMPTY(&w->crp_ret_kq) && TAILQ_EMPTY(&w->crp_ordered_ret_q))

static int crypto_workers_num = 0;
SYSCTL_INT(_kern_crypto, OID_AUTO, num_workers, CTLFLAG_RDTUN,
           &crypto_workers_num, 0,
           "Number of crypto workers used to dispatch crypto jobs");
#ifdef COMPAT_FREEBSD12
SYSCTL_INT(_kern, OID_AUTO, crypto_workers_num, CTLFLAG_RDTUN,
           &crypto_workers_num, 0,
           "Number of crypto workers used to dispatch crypto jobs");
#endif

static  uma_zone_t cryptop_zone;

int     crypto_userasymcrypto = 1;
SYSCTL_INT(_kern_crypto, OID_AUTO, asym_enable, CTLFLAG_RW,
           &crypto_userasymcrypto, 0,
           "Enable user-mode access to asymmetric crypto support");
#ifdef COMPAT_FREEBSD12
SYSCTL_INT(_kern, OID_AUTO, userasymcrypto, CTLFLAG_RW,
           &crypto_userasymcrypto, 0,
           "Enable/disable user-mode access to asymmetric crypto support");
#endif

int     crypto_devallowsoft = 0;
SYSCTL_INT(_kern_crypto, OID_AUTO, allow_soft, CTLFLAG_RWTUN,
           &crypto_devallowsoft, 0,
           "Enable use of software crypto by /dev/crypto");
#ifdef COMPAT_FREEBSD12
SYSCTL_INT(_kern, OID_AUTO, cryptodevallowsoft, CTLFLAG_RWTUN,
           &crypto_devallowsoft, 0,
           "Enable/disable use of software crypto by /dev/crypto");
#endif

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

static  void crypto_dispatch_thread(void *arg);
static  struct thread *cryptotd;
static  void crypto_ret_thread(void *arg);
static  void crypto_destroy(void);
static  int crypto_invoke(struct cryptocap *cap, struct cryptop *crp, int hint);
static  int crypto_kinvoke(struct cryptkop *krp);
static  void crypto_task_invoke(void *ctx, int pending);
static void crypto_batch_enqueue(struct cryptop *crp);

static counter_u64_t cryptostats[sizeof(struct cryptostats) / sizeof(uint64_t)];
SYSCTL_COUNTER_U64_ARRAY(_kern_crypto, OID_AUTO, stats, CTLFLAG_RW,
    cryptostats, nitems(cryptostats),
    "Crypto system statistics");

#define CRYPTOSTAT_INC(stat) do {                                       \
        counter_u64_add(                                                \
            cryptostats[offsetof(struct cryptostats, stat) / sizeof(uint64_t)],\
            1);                                                         \
} while (0)

static void
cryptostats_init(void *arg __unused)
{
        COUNTER_ARRAY_ALLOC(cryptostats, nitems(cryptostats), M_WAITOK);
}
SYSINIT(cryptostats_init, SI_SUB_COUNTER, SI_ORDER_ANY, cryptostats_init, NULL);

static void
cryptostats_fini(void *arg __unused)
{
        COUNTER_ARRAY_FREE(cryptostats, nitems(cryptostats));
}
SYSUNINIT(cryptostats_fini, SI_SUB_COUNTER, SI_ORDER_ANY, cryptostats_fini,
    NULL);

/* Try to avoid directly exposing the key buffer as a symbol */
static struct keybuf *keybuf;

static struct keybuf empty_keybuf = {
        .kb_nents = 0
};

/* Obtain the key buffer from boot metadata */
static void
keybuf_init(void)
{
        caddr_t kmdp;

        kmdp = preload_search_by_type("elf kernel");

        if (kmdp == NULL)
                kmdp = preload_search_by_type("elf64 kernel");

        keybuf = (struct keybuf *)preload_search_info(kmdp,
            MODINFO_METADATA | MODINFOMD_KEYBUF);

        if (keybuf == NULL)
                keybuf = &empty_keybuf;
}

/* It'd be nice if we could store these in some kind of secure memory... */
struct keybuf *
get_keybuf(void)
{

        return (keybuf);
}

static struct cryptocap *
cap_ref(struct cryptocap *cap)
{

        refcount_acquire(&cap->cc_refs);
        return (cap);
}

static void
cap_rele(struct cryptocap *cap)
{

        if (refcount_release(&cap->cc_refs) == 0)
                return;

        KASSERT(cap->cc_sessions == 0,
            ("freeing crypto driver with active sessions"));
        KASSERT(cap->cc_koperations == 0,
            ("freeing crypto driver with active key operations"));

        free(cap, M_CRYPTO_DATA);
}

static int
crypto_init(void)
{
        struct crypto_ret_worker *ret_worker;
        struct proc *p;
        int error;

        mtx_init(&crypto_drivers_mtx, "crypto driver table", NULL, MTX_DEF);

        TAILQ_INIT(&crp_q);
        TAILQ_INIT(&crp_kq);
        mtx_init(&crypto_q_mtx, "crypto op queues", NULL, MTX_DEF);

        cryptop_zone = uma_zcreate("cryptop",
            sizeof(struct cryptop), NULL, NULL, NULL, NULL,
            UMA_ALIGN_PTR, UMA_ZONE_ZINIT);

        crypto_drivers_size = CRYPTO_DRIVERS_INITIAL;
        crypto_drivers = malloc(crypto_drivers_size *
            sizeof(struct cryptocap), M_CRYPTO_DATA, M_WAITOK | M_ZERO);

        if (crypto_workers_num < 1 || crypto_workers_num > mp_ncpus)
                crypto_workers_num = mp_ncpus;

        crypto_tq = taskqueue_create("crypto", M_WAITOK | M_ZERO,
            taskqueue_thread_enqueue, &crypto_tq);

        taskqueue_start_threads(&crypto_tq, crypto_workers_num, PRI_MIN_KERN,
            "crypto");

        p = NULL;
        error = kproc_kthread_add(crypto_dispatch_thread, NULL, &p, &cryptotd,
            0, 0, "crypto", "crypto");
        if (error) {
                printf("crypto_init: cannot start crypto thread; error %d",
                        error);
                goto bad;
        }

        crypto_ret_workers = mallocarray(crypto_workers_num,
            sizeof(struct crypto_ret_worker), M_CRYPTO_DATA, M_WAITOK | M_ZERO);

        FOREACH_CRYPTO_RETW(ret_worker) {
                TAILQ_INIT(&ret_worker->crp_ordered_ret_q);
                TAILQ_INIT(&ret_worker->crp_ret_q);
                TAILQ_INIT(&ret_worker->crp_ret_kq);

                ret_worker->reorder_ops = 0;
                ret_worker->reorder_cur_seq = 0;

                mtx_init(&ret_worker->crypto_ret_mtx, "crypto return queues",
                    NULL, MTX_DEF);

                error = kthread_add(crypto_ret_thread, ret_worker, p,
                    &ret_worker->td, 0, 0, "crypto returns %td",
                    CRYPTO_RETW_ID(ret_worker));
                if (error) {
                        printf("crypto_init: cannot start cryptoret thread; error %d",
                                error);
                        goto bad;
                }
        }

        keybuf_init();

        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 **tdp, void *q)
{
        struct thread *td;

        mtx_assert(&crypto_drivers_mtx, MA_OWNED);
        td = *tdp;
        *tdp = NULL;
        if (td != NULL) {
                wakeup_one(q);
                mtx_sleep(td, &crypto_drivers_mtx, PWAIT, "crypto_destroy", 0);
        }
}

static void
hmac_init_pad(const struct auth_hash *axf, const char *key, int klen,
    void *auth_ctx, uint8_t padval)
{
        uint8_t hmac_key[HMAC_MAX_BLOCK_LEN];
        u_int i;

        KASSERT(axf->blocksize <= sizeof(hmac_key),
            ("Invalid HMAC block size %d", axf->blocksize));

        /*
         * If the key is larger than the block size, use the digest of
         * the key as the key instead.
         */
        memset(hmac_key, 0, sizeof(hmac_key));
        if (klen > axf->blocksize) {
                axf->Init(auth_ctx);
                axf->Update(auth_ctx, key, klen);
                axf->Final(hmac_key, auth_ctx);
                klen = axf->hashsize;
        } else
                memcpy(hmac_key, key, klen);

        for (i = 0; i < axf->blocksize; i++)
                hmac_key[i] ^= padval;

        axf->Init(auth_ctx);
        axf->Update(auth_ctx, hmac_key, axf->blocksize);
        explicit_bzero(hmac_key, sizeof(hmac_key));
}

void
hmac_init_ipad(const struct auth_hash *axf, const char *key, int klen,
    void *auth_ctx)
{

        hmac_init_pad(axf, key, klen, auth_ctx, HMAC_IPAD_VAL);
}

void
hmac_init_opad(const struct auth_hash *axf, const char *key, int klen,
    void *auth_ctx)
{

        hmac_init_pad(axf, key, klen, auth_ctx, HMAC_OPAD_VAL);
}

static void
crypto_destroy(void)
{
        struct crypto_ret_worker *ret_worker;
        int i;

        /*
         * Terminate any crypto threads.
         */
        if (crypto_tq != NULL)
                taskqueue_drain_all(crypto_tq);
        CRYPTO_DRIVER_LOCK();
        crypto_terminate(&cryptotd, &crp_q);
        FOREACH_CRYPTO_RETW(ret_worker)
                crypto_terminate(&ret_worker->td, &ret_worker->crp_ret_q);
        CRYPTO_DRIVER_UNLOCK();

        /* XXX flush queues??? */

        /*
         * Reclaim dynamically allocated resources.
         */
        for (i = 0; i < crypto_drivers_size; i++) {
                if (crypto_drivers[i] != NULL)
                        cap_rele(crypto_drivers[i]);
        }
        free(crypto_drivers, M_CRYPTO_DATA);

        if (cryptop_zone != NULL)
                uma_zdestroy(cryptop_zone);
        mtx_destroy(&crypto_q_mtx);
        FOREACH_CRYPTO_RETW(ret_worker)
                mtx_destroy(&ret_worker->crypto_ret_mtx);
        free(crypto_ret_workers, M_CRYPTO_DATA);
        if (crypto_tq != NULL)
                taskqueue_free(crypto_tq);
        mtx_destroy(&crypto_drivers_mtx);
}

uint32_t
crypto_ses2hid(crypto_session_t crypto_session)
{
        return (crypto_session->cap->cc_hid);
}

uint32_t
crypto_ses2caps(crypto_session_t crypto_session)
{
        return (crypto_session->cap->cc_flags & 0xff000000);
}

void *
crypto_get_driver_session(crypto_session_t crypto_session)
{
        return (crypto_session + 1);
}

const struct crypto_session_params *
crypto_get_params(crypto_session_t crypto_session)
{
        return (&crypto_session->csp);
}

struct auth_hash *
crypto_auth_hash(const struct crypto_session_params *csp)
{

        switch (csp->csp_auth_alg) {
        case CRYPTO_SHA1_HMAC:
                return (&auth_hash_hmac_sha1);
        case CRYPTO_SHA2_224_HMAC:
                return (&auth_hash_hmac_sha2_224);
        case CRYPTO_SHA2_256_HMAC:
                return (&auth_hash_hmac_sha2_256);
        case CRYPTO_SHA2_384_HMAC:
                return (&auth_hash_hmac_sha2_384);
        case CRYPTO_SHA2_512_HMAC:
                return (&auth_hash_hmac_sha2_512);
        case CRYPTO_NULL_HMAC:
                return (&auth_hash_null);
        case CRYPTO_RIPEMD160_HMAC:
                return (&auth_hash_hmac_ripemd_160);
        case CRYPTO_SHA1:
                return (&auth_hash_sha1);
        case CRYPTO_SHA2_224:
                return (&auth_hash_sha2_224);
        case CRYPTO_SHA2_256:
                return (&auth_hash_sha2_256);
        case CRYPTO_SHA2_384:
                return (&auth_hash_sha2_384);
        case CRYPTO_SHA2_512:
                return (&auth_hash_sha2_512);
        case CRYPTO_AES_NIST_GMAC:
                switch (csp->csp_auth_klen) {
                case 128 / 8:
                        return (&auth_hash_nist_gmac_aes_128);
                case 192 / 8:
                        return (&auth_hash_nist_gmac_aes_192);
                case 256 / 8:
                        return (&auth_hash_nist_gmac_aes_256);
                default:
                        return (NULL);
                }
        case CRYPTO_BLAKE2B:
                return (&auth_hash_blake2b);
        case CRYPTO_BLAKE2S:
                return (&auth_hash_blake2s);
        case CRYPTO_POLY1305:
                return (&auth_hash_poly1305);
        case CRYPTO_AES_CCM_CBC_MAC:
                switch (csp->csp_auth_klen) {
                case 128 / 8:
                        return (&auth_hash_ccm_cbc_mac_128);
                case 192 / 8:
                        return (&auth_hash_ccm_cbc_mac_192);
                case 256 / 8:
                        return (&auth_hash_ccm_cbc_mac_256);
                default:
                        return (NULL);
                }
        default:
                return (NULL);
        }
}

struct enc_xform *
crypto_cipher(const struct crypto_session_params *csp)
{

        switch (csp->csp_cipher_alg) {
        case CRYPTO_RIJNDAEL128_CBC:
                return (&enc_xform_rijndael128);
        case CRYPTO_AES_XTS:
                return (&enc_xform_aes_xts);
        case CRYPTO_AES_ICM:
                return (&enc_xform_aes_icm);
        case CRYPTO_AES_NIST_GCM_16:
                return (&enc_xform_aes_nist_gcm);
        case CRYPTO_CAMELLIA_CBC:
                return (&enc_xform_camellia);
        case CRYPTO_NULL_CBC:
                return (&enc_xform_null);
        case CRYPTO_CHACHA20:
                return (&enc_xform_chacha20);
        case CRYPTO_AES_CCM_16:
                return (&enc_xform_ccm);
        case CRYPTO_CHACHA20_POLY1305:
                return (&enc_xform_chacha20_poly1305);
        default:
                return (NULL);
        }
}

static struct cryptocap *
crypto_checkdriver(uint32_t hid)
{

        return (hid >= crypto_drivers_size ? NULL : crypto_drivers[hid]);
}

/*
 * Select a driver for a new session that supports the specified
 * algorithms and, optionally, is constrained according to the flags.
 */
static struct cryptocap *
crypto_select_driver(const struct crypto_session_params *csp, int flags)
{
        struct cryptocap *cap, *best;
        int best_match, error, hid;

        CRYPTO_DRIVER_ASSERT();

        best = NULL;
        for (hid = 0; hid < crypto_drivers_size; hid++) {
                /*
                 * If there is no driver for this slot, or the driver
                 * is not appropriate (hardware or software based on
                 * match), then skip.
                 */
                cap = crypto_drivers[hid];
                if (cap == NULL ||
                    (cap->cc_flags & flags) == 0)
                        continue;

                error = CRYPTODEV_PROBESESSION(cap->cc_dev, csp);
                if (error >= 0)
                        continue;

                /*
                 * Use the driver with the highest probe value.
                 * Hardware drivers use a higher probe value than
                 * software.  In case of a tie, prefer the driver with
                 * the fewest active sessions.
                 */
                if (best == NULL || error > best_match ||
                    (error == best_match &&
                    cap->cc_sessions < best->cc_sessions)) {
                        best = cap;
                        best_match = error;
                }
        }
        return best;
}

static enum alg_type {
        ALG_NONE = 0,
        ALG_CIPHER,
        ALG_DIGEST,
        ALG_KEYED_DIGEST,
        ALG_COMPRESSION,
        ALG_AEAD
} alg_types[] = {
        [CRYPTO_SHA1_HMAC] = ALG_KEYED_DIGEST,
        [CRYPTO_RIPEMD160_HMAC] = ALG_KEYED_DIGEST,
        [CRYPTO_AES_CBC] = ALG_CIPHER,
        [CRYPTO_SHA1] = ALG_DIGEST,
        [CRYPTO_NULL_HMAC] = ALG_DIGEST,
        [CRYPTO_NULL_CBC] = ALG_CIPHER,
        [CRYPTO_DEFLATE_COMP] = ALG_COMPRESSION,
        [CRYPTO_SHA2_256_HMAC] = ALG_KEYED_DIGEST,
        [CRYPTO_SHA2_384_HMAC] = ALG_KEYED_DIGEST,
        [CRYPTO_SHA2_512_HMAC] = ALG_KEYED_DIGEST,
        [CRYPTO_CAMELLIA_CBC] = ALG_CIPHER,
        [CRYPTO_AES_XTS] = ALG_CIPHER,
        [CRYPTO_AES_ICM] = ALG_CIPHER,
        [CRYPTO_AES_NIST_GMAC] = ALG_KEYED_DIGEST,
        [CRYPTO_AES_NIST_GCM_16] = ALG_AEAD,
        [CRYPTO_BLAKE2B] = ALG_KEYED_DIGEST,
        [CRYPTO_BLAKE2S] = ALG_KEYED_DIGEST,
        [CRYPTO_CHACHA20] = ALG_CIPHER,
        [CRYPTO_SHA2_224_HMAC] = ALG_KEYED_DIGEST,
        [CRYPTO_RIPEMD160] = ALG_DIGEST,
        [CRYPTO_SHA2_224] = ALG_DIGEST,
        [CRYPTO_SHA2_256] = ALG_DIGEST,
        [CRYPTO_SHA2_384] = ALG_DIGEST,
        [CRYPTO_SHA2_512] = ALG_DIGEST,
        [CRYPTO_POLY1305] = ALG_KEYED_DIGEST,
        [CRYPTO_AES_CCM_CBC_MAC] = ALG_KEYED_DIGEST,
        [CRYPTO_AES_CCM_16] = ALG_AEAD,
        [CRYPTO_CHACHA20_POLY1305] = ALG_AEAD,
};

static enum alg_type
alg_type(int alg)
{

        if (alg < nitems(alg_types))
                return (alg_types[alg]);
        return (ALG_NONE);
}

static bool
alg_is_compression(int alg)
{

        return (alg_type(alg) == ALG_COMPRESSION);
}

static bool
alg_is_cipher(int alg)
{

        return (alg_type(alg) == ALG_CIPHER);
}

static bool
alg_is_digest(int alg)
{

        return (alg_type(alg) == ALG_DIGEST ||
            alg_type(alg) == ALG_KEYED_DIGEST);
}

static bool
alg_is_keyed_digest(int alg)
{

        return (alg_type(alg) == ALG_KEYED_DIGEST);
}

static bool
alg_is_aead(int alg)
{

        return (alg_type(alg) == ALG_AEAD);
}

static bool
ccm_tag_length_valid(int len)
{
        /* RFC 3610 */
        switch (len) {
        case 4:
        case 6:
        case 8:
        case 10:
        case 12:
        case 14:
        case 16:
                return (true);
        default:
                return (false);
        }
}

#define SUPPORTED_SES (CSP_F_SEPARATE_OUTPUT | CSP_F_SEPARATE_AAD | CSP_F_ESN)

/* Various sanity checks on crypto session parameters. */
static bool
check_csp(const struct crypto_session_params *csp)
{
        struct auth_hash *axf;

        /* Mode-independent checks. */
        if ((csp->csp_flags & ~(SUPPORTED_SES)) != 0)
                return (false);
        if (csp->csp_ivlen < 0 || csp->csp_cipher_klen < 0 ||
            csp->csp_auth_klen < 0 || csp->csp_auth_mlen < 0)
                return (false);
        if (csp->csp_auth_key != NULL && csp->csp_auth_klen == 0)
                return (false);
        if (csp->csp_cipher_key != NULL && csp->csp_cipher_klen == 0)
                return (false);

        switch (csp->csp_mode) {
        case CSP_MODE_COMPRESS:
                if (!alg_is_compression(csp->csp_cipher_alg))
                        return (false);
                if (csp->csp_flags & CSP_F_SEPARATE_OUTPUT)
                        return (false);
                if (csp->csp_flags & CSP_F_SEPARATE_AAD)
                        return (false);
                if (csp->csp_cipher_klen != 0 || csp->csp_ivlen != 0 ||
                    csp->csp_auth_alg != 0 || csp->csp_auth_klen != 0 ||
                    csp->csp_auth_mlen != 0)
                        return (false);
                break;
        case CSP_MODE_CIPHER:
                if (!alg_is_cipher(csp->csp_cipher_alg))
                        return (false);
                if (csp->csp_flags & CSP_F_SEPARATE_AAD)
                        return (false);
                if (csp->csp_cipher_alg != CRYPTO_NULL_CBC) {
                        if (csp->csp_cipher_klen == 0)
                                return (false);
                        if (csp->csp_ivlen == 0)
                                return (false);
                }
                if (csp->csp_ivlen >= EALG_MAX_BLOCK_LEN)
                        return (false);
                if (csp->csp_auth_alg != 0 || csp->csp_auth_klen != 0 ||
                    csp->csp_auth_mlen != 0)
                        return (false);
                break;
        case CSP_MODE_DIGEST:
                if (csp->csp_cipher_alg != 0 || csp->csp_cipher_klen != 0)
                        return (false);

                if (csp->csp_flags & CSP_F_SEPARATE_AAD)
                        return (false);

                /* IV is optional for digests (e.g. GMAC). */
                switch (csp->csp_auth_alg) {
                case CRYPTO_AES_CCM_CBC_MAC:
                        if (csp->csp_ivlen < 7 || csp->csp_ivlen > 13)
                                return (false);
                        break;
                case CRYPTO_AES_NIST_GMAC:
                        if (csp->csp_ivlen != AES_GCM_IV_LEN)
                                return (false);
                        break;
                default:
                        if (csp->csp_ivlen != 0)
                                return (false);
                        break;
                }

                if (!alg_is_digest(csp->csp_auth_alg))
                        return (false);

                /* Key is optional for BLAKE2 digests. */
                if (csp->csp_auth_alg == CRYPTO_BLAKE2B ||
                    csp->csp_auth_alg == CRYPTO_BLAKE2S)
                        ;
                else if (alg_is_keyed_digest(csp->csp_auth_alg)) {
                        if (csp->csp_auth_klen == 0)
                                return (false);
                } else {
                        if (csp->csp_auth_klen != 0)
                                return (false);
                }
                if (csp->csp_auth_mlen != 0) {
                        axf = crypto_auth_hash(csp);
                        if (axf == NULL || csp->csp_auth_mlen > axf->hashsize)
                                return (false);

                        if (csp->csp_auth_alg == CRYPTO_AES_CCM_CBC_MAC &&
                            !ccm_tag_length_valid(csp->csp_auth_mlen))
                                return (false);
                }
                break;
        case CSP_MODE_AEAD:
                if (!alg_is_aead(csp->csp_cipher_alg))
                        return (false);
                if (csp->csp_cipher_klen == 0)
                        return (false);
                if (csp->csp_ivlen == 0 ||
                    csp->csp_ivlen >= EALG_MAX_BLOCK_LEN)
                        return (false);
                if (csp->csp_auth_alg != 0 || csp->csp_auth_klen != 0)
                        return (false);

                switch (csp->csp_cipher_alg) {
                case CRYPTO_AES_CCM_16:
                        if (csp->csp_auth_mlen != 0 &&
                            !ccm_tag_length_valid(csp->csp_auth_mlen))
                                return (false);

                        if (csp->csp_ivlen < 7 || csp->csp_ivlen > 13)
                                return (false);
                        break;
                case CRYPTO_AES_NIST_GCM_16:
                        if (csp->csp_auth_mlen > AES_GMAC_HASH_LEN)
                                return (false);

                        if (csp->csp_ivlen != AES_GCM_IV_LEN)
                                return (false);
                        break;
                case CRYPTO_CHACHA20_POLY1305:
                        if (csp->csp_ivlen != 8 && csp->csp_ivlen != 12)
                                return (false);
                        if (csp->csp_auth_mlen > POLY1305_HASH_LEN)
                                return (false);
                        break;
                }
                break;
        case CSP_MODE_ETA:
                if (!alg_is_cipher(csp->csp_cipher_alg))
                        return (false);
                if (csp->csp_cipher_alg != CRYPTO_NULL_CBC) {
                        if (csp->csp_cipher_klen == 0)
                                return (false);
                        if (csp->csp_ivlen == 0)
                                return (false);
                }
                if (csp->csp_ivlen >= EALG_MAX_BLOCK_LEN)
                        return (false);
                if (!alg_is_digest(csp->csp_auth_alg))
                        return (false);

                /* Key is optional for BLAKE2 digests. */
                if (csp->csp_auth_alg == CRYPTO_BLAKE2B ||
                    csp->csp_auth_alg == CRYPTO_BLAKE2S)
                        ;
                else if (alg_is_keyed_digest(csp->csp_auth_alg)) {
                        if (csp->csp_auth_klen == 0)
                                return (false);
                } else {
                        if (csp->csp_auth_klen != 0)
                                return (false);
                }
                if (csp->csp_auth_mlen != 0) {
                        axf = crypto_auth_hash(csp);
                        if (axf == NULL || csp->csp_auth_mlen > axf->hashsize)
                                return (false);
                }
                break;
        default:
                return (false);
        }

        return (true);
}

/*
 * Delete a session after it has been detached from its driver.
 */
static void
crypto_deletesession(crypto_session_t cses)
{
        struct cryptocap *cap;

        cap = cses->cap;

        zfree(cses, M_CRYPTO_DATA);

        CRYPTO_DRIVER_LOCK();
        cap->cc_sessions--;
        if (cap->cc_sessions == 0 && cap->cc_flags & CRYPTOCAP_F_CLEANUP)
                wakeup(cap);
        CRYPTO_DRIVER_UNLOCK();
        cap_rele(cap);
}

/*
 * 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(crypto_session_t *cses,
    const struct crypto_session_params *csp, int crid)
{
        static uint64_t sessid = 0;
        crypto_session_t res;
        struct cryptocap *cap;
        int err;

        if (!check_csp(csp))
                return (EINVAL);

        res = NULL;

        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 && CRYPTODEV_PROBESESSION(cap->cc_dev, csp) > 0)
                        cap = NULL;
        } else {
                /*
                 * No requested driver; select based on crid flags.
                 */
                cap = crypto_select_driver(csp, crid);
        }
        if (cap == NULL) {
                CRYPTO_DRIVER_UNLOCK();
                CRYPTDEB("no driver");
                return (EOPNOTSUPP);
        }
        cap_ref(cap);
        cap->cc_sessions++;
        CRYPTO_DRIVER_UNLOCK();

        /* Allocate a single block for the generic session and driver softc. */
        res = malloc(sizeof(*res) + cap->cc_session_size, M_CRYPTO_DATA,
            M_WAITOK | M_ZERO);
        res->cap = cap;
        res->csp = *csp;
        res->id = atomic_fetchadd_64(&sessid, 1);

        /* Call the driver initialization routine. */
        err = CRYPTODEV_NEWSESSION(cap->cc_dev, res, csp);
        if (err != 0) {
                CRYPTDEB("dev newsession failed: %d", err);
                crypto_deletesession(res);
                return (err);
        }

        *cses = res;
        return (0);
}

/*
 * Delete an existing session (or a reserved session on an unregistered
 * driver).
 */
void
crypto_freesession(crypto_session_t cses)
{
        struct cryptocap *cap;

        if (cses == NULL)
                return;

        cap = cses->cap;

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

        crypto_deletesession(cses);
}

/*
 * Return a new driver id.  Registers a driver with the system so that
 * it can be probed by subsequent sessions.
 */
int32_t
crypto_get_driverid(device_t dev, size_t sessionsize, int flags)
{
        struct cryptocap *cap, **newdrv;
        int i;

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

        cap = malloc(sizeof(*cap), M_CRYPTO_DATA, M_WAITOK | M_ZERO);
        cap->cc_dev = dev;
        cap->cc_session_size = sessionsize;
        cap->cc_flags = flags;
        refcount_init(&cap->cc_refs, 1);

        CRYPTO_DRIVER_LOCK();
        for (;;) {
                for (i = 0; i < crypto_drivers_size; i++) {
                        if (crypto_drivers[i] == NULL)
                                break;
                }

                if (i < crypto_drivers_size)
                        break;

                /* Out of entries, allocate some more. */

                if (2 * crypto_drivers_size <= crypto_drivers_size) {
                        CRYPTO_DRIVER_UNLOCK();
                        printf("crypto: driver count wraparound!\n");
                        cap_rele(cap);
                        return (-1);
                }
                CRYPTO_DRIVER_UNLOCK();

                newdrv = malloc(2 * crypto_drivers_size *
                    sizeof(*crypto_drivers), M_CRYPTO_DATA, M_WAITOK | M_ZERO);

                CRYPTO_DRIVER_LOCK();
                memcpy(newdrv, crypto_drivers,
                    crypto_drivers_size * sizeof(*crypto_drivers));

                crypto_drivers_size *= 2;

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

        cap->cc_hid = i;
        crypto_drivers[i] = cap;
        CRYPTO_DRIVER_UNLOCK();

        if (bootverbose)
                printf("crypto: assign %s driver id %u, flags 0x%x\n",
                    device_get_nameunit(dev), i, flags);

        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)
{
        struct cryptocap *cap;
        int i, len = strlen(match);

        CRYPTO_DRIVER_LOCK();
        for (i = 0; i < crypto_drivers_size; i++) {
                if (crypto_drivers[i] == NULL)
                        continue;
                cap = crypto_drivers[i];
                if (strncmp(match, device_get_nameunit(cap->cc_dev), len) == 0 ||
                    strncmp(match, device_get_name(cap->cc_dev), len) == 0) {
                        CRYPTO_DRIVER_UNLOCK();
                        return (i);
                }
        }
        CRYPTO_DRIVER_UNLOCK();
        return (-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;
        device_t dev;

        dev = NULL;
        CRYPTO_DRIVER_LOCK();
        cap = crypto_checkdriver(hid);
        if (cap != NULL)
                dev = cap->cc_dev;
        CRYPTO_DRIVER_UNLOCK();
        return (dev);
}

/*
 * Return the device/driver capabilities.
 */
int
crypto_getcaps(int hid)
{
        struct cryptocap *cap;
        int flags;

        flags = 0;
        CRYPTO_DRIVER_LOCK();
        cap = crypto_checkdriver(hid);
        if (cap != NULL)
                flags = cap->cc_flags;
        CRYPTO_DRIVER_UNLOCK();
        return (flags);
}

/*
 * Register support for a key-related algorithm.  This routine
 * is called once for each algorithm supported a driver.
 */
int
crypto_kregister(uint32_t driverid, int kalg, uint32_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)
                        printf("crypto: %s registers key alg %u flags %u\n"
                                , device_get_nameunit(cap->cc_dev)
                                , kalg
                                , flags
                        );
                gone_in_dev(cap->cc_dev, 14, "asymmetric crypto");
                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(uint32_t driverid)
{
        struct cryptocap *cap;

        CRYPTO_DRIVER_LOCK();
        cap = crypto_checkdriver(driverid);
        if (cap == NULL) {
                CRYPTO_DRIVER_UNLOCK();
                return (EINVAL);
        }

        cap->cc_flags |= CRYPTOCAP_F_CLEANUP;
        crypto_drivers[driverid] = NULL;

        /*
         * XXX: This doesn't do anything to kick sessions that
         * have no pending operations.
         */
        while (cap->cc_sessions != 0 || cap->cc_koperations != 0)
                mtx_sleep(cap, &crypto_drivers_mtx, 0, "cryunreg", 0);
        CRYPTO_DRIVER_UNLOCK();
        cap_rele(cap);

        return (0);
}

/*
 * 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(uint32_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;
}

size_t
crypto_buffer_len(struct crypto_buffer *cb)
{
        switch (cb->cb_type) {
        case CRYPTO_BUF_CONTIG:
                return (cb->cb_buf_len);
        case CRYPTO_BUF_MBUF:
                if (cb->cb_mbuf->m_flags & M_PKTHDR)
                        return (cb->cb_mbuf->m_pkthdr.len);
                return (m_length(cb->cb_mbuf, NULL));
        case CRYPTO_BUF_SINGLE_MBUF:
                return (cb->cb_mbuf->m_len);
        case CRYPTO_BUF_VMPAGE:
                return (cb->cb_vm_page_len);
        case CRYPTO_BUF_UIO:
                return (cb->cb_uio->uio_resid);
        default:
                return (0);
        }
}

#ifdef INVARIANTS
/* Various sanity checks on crypto requests. */
static void
cb_sanity(struct crypto_buffer *cb, const char *name)
{
        KASSERT(cb->cb_type > CRYPTO_BUF_NONE && cb->cb_type <= CRYPTO_BUF_LAST,
            ("incoming crp with invalid %s buffer type", name));
        switch (cb->cb_type) {
        case CRYPTO_BUF_CONTIG:
                KASSERT(cb->cb_buf_len >= 0,
                    ("incoming crp with -ve %s buffer length", name));
                break;
        case CRYPTO_BUF_VMPAGE:
                KASSERT(CRYPTO_HAS_VMPAGE,
                    ("incoming crp uses dmap on supported arch"));
                KASSERT(cb->cb_vm_page_len >= 0,
                    ("incoming crp with -ve %s buffer length", name));
                KASSERT(cb->cb_vm_page_offset >= 0,
                    ("incoming crp with -ve %s buffer offset", name));
                KASSERT(cb->cb_vm_page_offset < PAGE_SIZE,
                    ("incoming crp with %s buffer offset greater than page size"
                     , name));
                break;
        default:
                break;
        }
}

static void
crp_sanity(struct cryptop *crp)
{
        struct crypto_session_params *csp;
        struct crypto_buffer *out;
        size_t ilen, len, olen;

        KASSERT(crp->crp_session != NULL, ("incoming crp without a session"));
        KASSERT(crp->crp_obuf.cb_type >= CRYPTO_BUF_NONE &&
            crp->crp_obuf.cb_type <= CRYPTO_BUF_LAST,
            ("incoming crp with invalid output buffer type"));
        KASSERT(crp->crp_etype == 0, ("incoming crp with error"));
        KASSERT(!(crp->crp_flags & CRYPTO_F_DONE),
            ("incoming crp already done"));

        csp = &crp->crp_session->csp;
        cb_sanity(&crp->crp_buf, "input");
        ilen = crypto_buffer_len(&crp->crp_buf);
        olen = ilen;
        out = NULL;
        if (csp->csp_flags & CSP_F_SEPARATE_OUTPUT) {
                if (crp->crp_obuf.cb_type != CRYPTO_BUF_NONE) {
                        cb_sanity(&crp->crp_obuf, "output");
                        out = &crp->crp_obuf;
                        olen = crypto_buffer_len(out);
                }
        } else
                KASSERT(crp->crp_obuf.cb_type == CRYPTO_BUF_NONE,
                    ("incoming crp with separate output buffer "
                    "but no session support"));

        switch (csp->csp_mode) {
        case CSP_MODE_COMPRESS:
                KASSERT(crp->crp_op == CRYPTO_OP_COMPRESS ||
                    crp->crp_op == CRYPTO_OP_DECOMPRESS,
                    ("invalid compression op %x", crp->crp_op));
                break;
        case CSP_MODE_CIPHER:
                KASSERT(crp->crp_op == CRYPTO_OP_ENCRYPT ||
                    crp->crp_op == CRYPTO_OP_DECRYPT,
                    ("invalid cipher op %x", crp->crp_op));
                break;
        case CSP_MODE_DIGEST:
                KASSERT(crp->crp_op == CRYPTO_OP_COMPUTE_DIGEST ||
                    crp->crp_op == CRYPTO_OP_VERIFY_DIGEST,
                    ("invalid digest op %x", crp->crp_op));
                break;
        case CSP_MODE_AEAD:
                KASSERT(crp->crp_op ==
                    (CRYPTO_OP_ENCRYPT | CRYPTO_OP_COMPUTE_DIGEST) ||
                    crp->crp_op ==
                    (CRYPTO_OP_DECRYPT | CRYPTO_OP_VERIFY_DIGEST),
                    ("invalid AEAD op %x", crp->crp_op));
                KASSERT(crp->crp_flags & CRYPTO_F_IV_SEPARATE,
                    ("AEAD without a separate IV"));
                break;
        case CSP_MODE_ETA:
                KASSERT(crp->crp_op ==
                    (CRYPTO_OP_ENCRYPT | CRYPTO_OP_COMPUTE_DIGEST) ||
                    crp->crp_op ==
                    (CRYPTO_OP_DECRYPT | CRYPTO_OP_VERIFY_DIGEST),
                    ("invalid ETA op %x", crp->crp_op));
                break;
        }
        if (csp->csp_mode == CSP_MODE_AEAD || csp->csp_mode == CSP_MODE_ETA) {
                if (crp->crp_aad == NULL) {
                        KASSERT(crp->crp_aad_start == 0 ||
                            crp->crp_aad_start < ilen,
                            ("invalid AAD start"));
                        KASSERT(crp->crp_aad_length != 0 ||
                            crp->crp_aad_start == 0,
                            ("AAD with zero length and non-zero start"));
                        KASSERT(crp->crp_aad_length == 0 ||
                            crp->crp_aad_start + crp->crp_aad_length <= ilen,
                            ("AAD outside input length"));
                } else {
                        KASSERT(csp->csp_flags & CSP_F_SEPARATE_AAD,
                            ("session doesn't support separate AAD buffer"));
                        KASSERT(crp->crp_aad_start == 0,
                            ("separate AAD buffer with non-zero AAD start"));
                        KASSERT(crp->crp_aad_length != 0,
                            ("separate AAD buffer with zero length"));
                }
        } else {
                KASSERT(crp->crp_aad == NULL && crp->crp_aad_start == 0 &&
                    crp->crp_aad_length == 0,
                    ("AAD region in request not supporting AAD"));
        }
        if (csp->csp_ivlen == 0) {
                KASSERT((crp->crp_flags & CRYPTO_F_IV_SEPARATE) == 0,
                    ("IV_SEPARATE set when IV isn't used"));
                KASSERT(crp->crp_iv_start == 0,
                    ("crp_iv_start set when IV isn't used"));
        } else if (crp->crp_flags & CRYPTO_F_IV_SEPARATE) {
                KASSERT(crp->crp_iv_start == 0,
                    ("IV_SEPARATE used with non-zero IV start"));
        } else {
                KASSERT(crp->crp_iv_start < ilen,
                    ("invalid IV start"));
                KASSERT(crp->crp_iv_start + csp->csp_ivlen <= ilen,
                    ("IV outside buffer length"));
        }
        /* XXX: payload_start of 0 should always be < ilen? */
        KASSERT(crp->crp_payload_start == 0 ||
            crp->crp_payload_start < ilen,
            ("invalid payload start"));
        KASSERT(crp->crp_payload_start + crp->crp_payload_length <=
            ilen, ("payload outside input buffer"));
        if (out == NULL) {
                KASSERT(crp->crp_payload_output_start == 0,
                    ("payload output start non-zero without output buffer"));
        } else {
                KASSERT(crp->crp_payload_output_start == 0 ||
                    crp->crp_payload_output_start < olen,
                    ("invalid payload output start"));
                KASSERT(crp->crp_payload_output_start +
                    crp->crp_payload_length <= olen,
                    ("payload outside output buffer"));
        }
        if (csp->csp_mode == CSP_MODE_DIGEST ||
            csp->csp_mode == CSP_MODE_AEAD || csp->csp_mode == CSP_MODE_ETA) {
                if (crp->crp_op & CRYPTO_OP_VERIFY_DIGEST)
                        len = ilen;
                else
                        len = olen;
                KASSERT(crp->crp_digest_start == 0 ||
                    crp->crp_digest_start < len,
                    ("invalid digest start"));
                /* XXX: For the mlen == 0 case this check isn't perfect. */
                KASSERT(crp->crp_digest_start + csp->csp_auth_mlen <= len,
                    ("digest outside buffer"));
        } else {
                KASSERT(crp->crp_digest_start == 0,
                    ("non-zero digest start for request without a digest"));
        }
        if (csp->csp_cipher_klen != 0)
                KASSERT(csp->csp_cipher_key != NULL ||
                    crp->crp_cipher_key != NULL,
                    ("cipher request without a key"));
        if (csp->csp_auth_klen != 0)
                KASSERT(csp->csp_auth_key != NULL || crp->crp_auth_key != NULL,
                    ("auth request without a key"));
        KASSERT(crp->crp_callback != NULL, ("incoming crp without callback"));
}
#endif

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

#ifdef INVARIANTS
        crp_sanity(crp);
#endif

        CRYPTOSTAT_INC(cs_ops);

        crp->crp_retw_id = crp->crp_session->id % crypto_workers_num;

        if (CRYPTOP_ASYNC(crp)) {
                if (crp->crp_flags & CRYPTO_F_ASYNC_KEEPORDER) {
                        struct crypto_ret_worker *ret_worker;

                        ret_worker = CRYPTO_RETW(crp->crp_retw_id);

                        CRYPTO_RETW_LOCK(ret_worker);
                        crp->crp_seq = ret_worker->reorder_ops++;
                        CRYPTO_RETW_UNLOCK(ret_worker);
                }

                TASK_INIT(&crp->crp_task, 0, crypto_task_invoke, crp);
                taskqueue_enqueue(crypto_tq, &crp->crp_task);
                return (0);
        }

        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 = crp->crp_session->cap;
                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_batch_enqueue(crp);
        return 0;
}

void
crypto_batch_enqueue(struct cryptop *crp)
{

        CRYPTO_Q_LOCK();
        TAILQ_INSERT_TAIL(&crp_q, crp, crp_next);
        if (crp_sleep)
                wakeup_one(&crp_q);
        CRYPTO_Q_UNLOCK();
}

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

        CRYPTOSTAT_INC(cs_kops);

        krp->krp_cap = NULL;
        error = crypto_kinvoke(krp);
        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;
        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_size; hid++) {
                /*
                 * If there is no driver for this slot, or the driver
                 * is not appropriate (hardware or software based on
                 * match), then skip.
                 */
                cap = crypto_drivers[hid];
                if (cap == NULL ||
                    (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;
}

/*
 * Choose a driver for an asymmetric crypto request.
 */
static struct cryptocap *
crypto_lookup_kdriver(struct cryptkop *krp)
{
        struct cryptocap *cap;
        uint32_t crid;

        /* If this request is requeued, it might already have a driver. */
        cap = krp->krp_cap;
        if (cap != NULL)
                return (cap);

        /* Use krp_crid to choose a driver. */
        crid = krp->krp_crid;
        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) {
                krp->krp_cap = cap_ref(cap);
                krp->krp_hid = cap->cc_hid;
        }
        return (cap);
}

/*
 * Dispatch an asymmetric crypto request.
 */
static int
crypto_kinvoke(struct cryptkop *krp)
{
        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();
        cap = crypto_lookup_kdriver(krp);
        if (cap == NULL) {
                CRYPTO_DRIVER_UNLOCK();
                krp->krp_status = ENODEV;
                crypto_kdone(krp);
                return (0);
        }

        /*
         * If the device is blocked, return ERESTART to requeue it.
         */
        if (cap->cc_kqblocked) {
                /*
                 * XXX: Previously this set krp_status to ERESTART and
                 * invoked crypto_kdone but the caller would still
                 * requeue it.
                 */
                CRYPTO_DRIVER_UNLOCK();
                return (ERESTART);
        }

        cap->cc_koperations++;
        CRYPTO_DRIVER_UNLOCK();
        error = CRYPTODEV_KPROCESS(cap->cc_dev, krp, 0);
        if (error == ERESTART) {
                CRYPTO_DRIVER_LOCK();
                cap->cc_koperations--;
                CRYPTO_DRIVER_UNLOCK();
                return (error);
        }

        KASSERT(error == 0, ("error %d returned from crypto_kprocess", error));
        return (0);
}

static void
crypto_task_invoke(void *ctx, int pending)
{
        struct cryptocap *cap;
        struct cryptop *crp;
        int result;

        crp = (struct cryptop *)ctx;
        cap = crp->crp_session->cap;
        result = crypto_invoke(cap, crp, 0);
        if (result == ERESTART)
                crypto_batch_enqueue(crp);
}

/*
 * 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_session != NULL,
            ("%s: crp->crp_session == NULL", __func__));

        if (cap->cc_flags & CRYPTOCAP_F_CLEANUP) {
                struct crypto_session_params csp;
                crypto_session_t nses;

                /*
                 * 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?
                 *
                 * XXX: Real solution is to make sessions refcounted
                 * and force callers to hold a reference when
                 * assigning to crp_session.  Could maybe change
                 * crypto_getreq to accept a session pointer to make
                 * that work.  Alternatively, we could abandon the
                 * notion of rewriting crp_session in requests forcing
                 * the caller to deal with allocating a new session.
                 * Perhaps provide a method to allow a crp's session to
                 * be swapped that callers could use.
                 */
                csp = crp->crp_session->csp;
                crypto_freesession(crp->crp_session);

                /*
                 * XXX: Key pointers may no longer be valid.  If we
                 * really want to support this we need to define the
                 * KPI such that 'csp' is required to be valid for the
                 * duration of a session by the caller perhaps.
                 *
                 * XXX: If the keys have been changed this will reuse
                 * the old keys.  This probably suggests making
                 * rekeying more explicit and updating the key
                 * pointers in 'csp' when the keys change.
                 */
                if (crypto_newsession(&nses, &csp,
                    CRYPTOCAP_F_HARDWARE | CRYPTOCAP_F_SOFTWARE) == 0)
                        crp->crp_session = nses;

                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);
        }
}

void
crypto_destroyreq(struct cryptop *crp)
{
#ifdef DIAGNOSTIC
        {
                struct cryptop *crp2;
                struct crypto_ret_worker *ret_worker;

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

                FOREACH_CRYPTO_RETW(ret_worker) {
                        CRYPTO_RETW_LOCK(ret_worker);
                        TAILQ_FOREACH(crp2, &ret_worker->crp_ret_q, crp_next) {
                                KASSERT(crp2 != crp,
                                    ("Freeing cryptop from the return queue (%p).",
                                    crp));
                        }
                        CRYPTO_RETW_UNLOCK(ret_worker);
                }
        }
#endif
}

void
crypto_freereq(struct cryptop *crp)
{
        if (crp == NULL)
                return;

        crypto_destroyreq(crp);
        uma_zfree(cryptop_zone, crp);
}

static void
_crypto_initreq(struct cryptop *crp, crypto_session_t cses)
{
        crp->crp_session = cses;
}

void
crypto_initreq(struct cryptop *crp, crypto_session_t cses)
{
        memset(crp, 0, sizeof(*crp));
        _crypto_initreq(crp, cses);
}

struct cryptop *
crypto_getreq(crypto_session_t cses, int how)
{
        struct cryptop *crp;

        MPASS(how == M_WAITOK || how == M_NOWAIT);
        crp = uma_zalloc(cryptop_zone, how | M_ZERO);
        if (crp != NULL)
                _crypto_initreq(crp, cses);
        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)
                CRYPTOSTAT_INC(cs_errs);

        /*
         * 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 (!CRYPTOP_ASYNC_KEEPORDER(crp) &&
            ((crp->crp_flags & CRYPTO_F_CBIMM) ||
            ((crp->crp_flags & CRYPTO_F_CBIFSYNC) &&
             (crypto_ses2caps(crp->crp_session) & 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).
                 */
                crp->crp_callback(crp);
        } else {
                struct crypto_ret_worker *ret_worker;
                bool wake;

                ret_worker = CRYPTO_RETW(crp->crp_retw_id);
                wake = false;

                /*
                 * Normal case; queue the callback for the thread.
                 */
                CRYPTO_RETW_LOCK(ret_worker);
                if (CRYPTOP_ASYNC_KEEPORDER(crp)) {
                        struct cryptop *tmp;

                        TAILQ_FOREACH_REVERSE(tmp, &ret_worker->crp_ordered_ret_q,
                                        cryptop_q, crp_next) {
                                if (CRYPTO_SEQ_GT(crp->crp_seq, tmp->crp_seq)) {
                                        TAILQ_INSERT_AFTER(&ret_worker->crp_ordered_ret_q,
                                                        tmp, crp, crp_next);
                                        break;
                                }
                        }
                        if (tmp == NULL) {
                                TAILQ_INSERT_HEAD(&ret_worker->crp_ordered_ret_q,
                                                crp, crp_next);
                        }

                        if (crp->crp_seq == ret_worker->reorder_cur_seq)
                                wake = true;
                }
                else {
                        if (CRYPTO_RETW_EMPTY(ret_worker))
                                wake = true;

                        TAILQ_INSERT_TAIL(&ret_worker->crp_ret_q, crp, crp_next);
                }

                if (wake)
                        wakeup_one(&ret_worker->crp_ret_q);     /* shared wait channel */
                CRYPTO_RETW_UNLOCK(ret_worker);
        }
}

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

        if (krp->krp_status != 0)
                CRYPTOSTAT_INC(cs_kerrs);
        cap = krp->krp_cap;
        if (cap != NULL) {
                CRYPTO_DRIVER_LOCK();
                KASSERT(cap->cc_koperations > 0, ("cc_koperations == 0"));
                cap->cc_koperations--;
                if (cap->cc_koperations == 0 &&
                    cap->cc_flags & CRYPTOCAP_F_CLEANUP)
                        wakeup(cap);
                CRYPTO_DRIVER_UNLOCK();
                krp->krp_cap = NULL;
                cap_rele(cap);
        }

        ret_worker = CRYPTO_RETW(0);

        CRYPTO_RETW_LOCK(ret_worker);
        if (CRYPTO_RETW_EMPTY(ret_worker))
                wakeup_one(&ret_worker->crp_ret_q);             /* shared wait channel */
        TAILQ_INSERT_TAIL(&ret_worker->crp_ret_kq, krp, krp_next);
        CRYPTO_RETW_UNLOCK(ret_worker);
}

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

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

                if (cap == NULL ||
                    ((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_dispatch_thread(void *arg __unused)
{
        struct cryptop *crp, *submit;
        struct cryptkop *krp;
        struct cryptocap *cap;
        int result, hint;

#if defined(__i386__) || defined(__amd64__) || defined(__aarch64__)
        fpu_kern_thread(FPU_KERN_NORMAL);
#endif

        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) {
                        cap = crp->crp_session->cap;
                        /*
                         * Driver cannot disappeared when there is an active
                         * session.
                         */
                        KASSERT(cap != NULL, ("%s:%u Driver disappeared.",
                            __func__, __LINE__));
                        if (cap->cc_flags & CRYPTOCAP_F_CLEANUP) {
                                /* 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 (submit->crp_session->cap == cap)
                                                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);
                        cap = submit->crp_session->cap;
                        KASSERT(cap != NULL, ("%s:%u Driver disappeared.",
                            __func__, __LINE__));
                        CRYPTO_Q_UNLOCK();
                        result = crypto_invoke(cap, submit, hint);
                        CRYPTO_Q_LOCK();
                        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.
                                 */
                                cap->cc_qblocked = 1;
                                TAILQ_INSERT_HEAD(&crp_q, submit, crp_next);
                                CRYPTOSTAT_INC(cs_blocks);
                        }
                }

                /* As above, but for key ops */
                TAILQ_FOREACH(krp, &crp_kq, krp_next) {
                        cap = krp->krp_cap;
                        if (cap->cc_flags & CRYPTOCAP_F_CLEANUP) {
                                /*
                                 * Operation needs to be migrated,
                                 * clear krp_cap so a new driver is
                                 * selected.
                                 */
                                krp->krp_cap = NULL;
                                cap_rele(cap);
                                break;
                        }
                        if (!cap->cc_kqblocked)
                                break;
                }
                if (krp != NULL) {
                        TAILQ_REMOVE(&crp_kq, krp, krp_next);
                        CRYPTO_Q_UNLOCK();
                        result = crypto_kinvoke(krp);
                        CRYPTO_Q_LOCK();
                        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.
                                 */
                                krp->krp_cap->cc_kqblocked = 1;
                                TAILQ_INSERT_HEAD(&crp_kq, krp, krp_next);
                                CRYPTOSTAT_INC(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;
                        msleep(&crp_q, &crypto_q_mtx, PWAIT, "crypto_wait", 0);
                        crp_sleep = 0;
                        if (cryptotd == NULL)
                                break;
                        CRYPTOSTAT_INC(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_thread(void *arg)
{
        struct crypto_ret_worker *ret_worker = arg;
        struct cryptop *crpt;
        struct cryptkop *krpt;

        CRYPTO_RETW_LOCK(ret_worker);
        for (;;) {
                /* Harvest return q's for completed ops */
                crpt = TAILQ_FIRST(&ret_worker->crp_ordered_ret_q);
                if (crpt != NULL) {
                        if (crpt->crp_seq == ret_worker->reorder_cur_seq) {
                                TAILQ_REMOVE(&ret_worker->crp_ordered_ret_q, crpt, crp_next);
                                ret_worker->reorder_cur_seq++;
                        } else {
                                crpt = NULL;
                        }
                }

                if (crpt == NULL) {
                        crpt = TAILQ_FIRST(&ret_worker->crp_ret_q);
                        if (crpt != NULL)
                                TAILQ_REMOVE(&ret_worker->crp_ret_q, crpt, crp_next);
                }

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

                if (crpt != NULL || krpt != NULL) {
                        CRYPTO_RETW_UNLOCK(ret_worker);
                        /*
                         * Run callbacks unlocked.
                         */
                        if (crpt != NULL)
                                crpt->crp_callback(crpt);
                        if (krpt != NULL)
                                krpt->krp_callback(krpt);
                        CRYPTO_RETW_LOCK(ret_worker);
                } else {
                        /*
                         * Nothing more to be processed.  Sleep until we're
                         * woken because there are more returns to process.
                         */
                        msleep(&ret_worker->crp_ret_q, &ret_worker->crypto_ret_mtx, PWAIT,
                                "crypto_ret_wait", 0);
                        if (ret_worker->td == NULL)
                                break;
                        CRYPTOSTAT_INC(cs_rets);
                }
        }
        CRYPTO_RETW_UNLOCK(ret_worker);

        crypto_finis(&ret_worker->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_size; hid++) {
                const struct cryptocap *cap = crypto_drivers[hid];
                if (cap == 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;
        struct crypto_ret_worker *ret_worker;

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

        db_printf("%4s %8s %4s %4s %4s %4s %8s %8s\n",
            "HID", "Caps", "Ilen", "Olen", "Etype", "Flags",
            "Device", "Callback");
        TAILQ_FOREACH(crp, &crp_q, crp_next) {
                db_printf("%4u %08x %4u %4u %04x %8p %8p\n"
                    , crp->crp_session->cap->cc_hid
                    , (int) crypto_ses2caps(crp->crp_session)
                    , crp->crp_olen
                    , crp->crp_etype
                    , crp->crp_flags
                    , device_get_nameunit(crp->crp_session->cap->cc_dev)
                    , crp->crp_callback
                );
        }
        FOREACH_CRYPTO_RETW(ret_worker) {
                db_printf("\n%8s %4s %4s %4s %8s\n",
                    "ret_worker", "HID", "Etype", "Flags", "Callback");
                if (!TAILQ_EMPTY(&ret_worker->crp_ret_q)) {
                        TAILQ_FOREACH(crp, &ret_worker->crp_ret_q, crp_next) {
                                db_printf("%8td %4u %4u %04x %8p\n"
                                    , CRYPTO_RETW_ID(ret_worker)
                                    , crp->crp_session->cap->cc_hid
                                    , crp->crp_etype
                                    , crp->crp_flags
                                    , crp->crp_callback
                                );
                        }
                }
        }
}

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

        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
                );
        }

        ret_worker = CRYPTO_RETW(0);
        if (!TAILQ_EMPTY(&ret_worker->crp_ret_q)) {
                db_printf("%4s %5s %8s %4s %8s\n",
                    "Op", "Status", "CRID", "HID", "Callback");
                TAILQ_FOREACH(krp, &ret_worker->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)
                        printf("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);