/*-
 * Copyright (c) 2018 Conrad Meyer <cem@FreeBSD.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``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 AUTHORS OR CONTRIBUTORS 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/param.h>
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/kobj.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <sys/smp.h>

#include <blake2.h>

#include <opencrypto/cryptodev.h>
#include <cryptodev_if.h>

#include <machine/fpu.h>

struct blake2_session {
        size_t mlen;
};
CTASSERT((size_t)BLAKE2B_KEYBYTES > (size_t)BLAKE2S_KEYBYTES);

struct blake2_softc {
        int32_t cid;
};

static int blake2_cipher_setup(struct blake2_session *ses,
    const struct crypto_session_params *csp);
static int blake2_cipher_process(struct blake2_session *ses,
    struct cryptop *crp);

MALLOC_DEFINE(M_BLAKE2, "blake2_data", "Blake2 Data");

static void
blake2_identify(driver_t *drv, device_t parent)
{

        /* NB: order 10 is so we get attached after h/w devices */
        if (device_find_child(parent, "blaketwo", DEVICE_UNIT_ANY) == NULL &&
            BUS_ADD_CHILD(parent, 10, "blaketwo", DEVICE_UNIT_ANY) == 0)
                panic("blaketwo: could not attach");
}

static int
blake2_probe(device_t dev)
{
        device_set_desc(dev, "Blake2");
        return (0);
}

static int
blake2_attach(device_t dev)
{
        struct blake2_softc *sc;

        sc = device_get_softc(dev);

        sc->cid = crypto_get_driverid(dev, sizeof(struct blake2_session),
            CRYPTOCAP_F_SOFTWARE | CRYPTOCAP_F_SYNC |
            CRYPTOCAP_F_ACCEL_SOFTWARE);
        if (sc->cid < 0) {
                device_printf(dev, "Could not get crypto driver id.\n");
                return (ENOMEM);
        }

        return (0);
}

static int
blake2_detach(device_t dev)
{
        struct blake2_softc *sc;

        sc = device_get_softc(dev);

        crypto_unregister_all(sc->cid);

        return (0);
}

static int
blake2_probesession(device_t dev, const struct crypto_session_params *csp)
{

        if (csp->csp_flags != 0)
                return (EINVAL);
        switch (csp->csp_mode) {
        case CSP_MODE_DIGEST:
                switch (csp->csp_auth_alg) {
                case CRYPTO_BLAKE2B:
                case CRYPTO_BLAKE2S:
                        break;
                default:
                        return (EINVAL);
                }
                break;
        default:
                return (EINVAL);
        }
        return (CRYPTODEV_PROBE_ACCEL_SOFTWARE);
}

static int
blake2_newsession(device_t dev, crypto_session_t cses,
    const struct crypto_session_params *csp)
{
        struct blake2_session *ses;
        int error;

        ses = crypto_get_driver_session(cses);

        error = blake2_cipher_setup(ses, csp);
        if (error != 0) {
                CRYPTDEB("setup failed");
                return (error);
        }

        return (0);
}

static int
blake2_process(device_t dev, struct cryptop *crp, int hint __unused)
{
        struct blake2_session *ses;
        int error;

        ses = crypto_get_driver_session(crp->crp_session);
        error = blake2_cipher_process(ses, crp);

        crp->crp_etype = error;
        crypto_done(crp);
        return (0);
}

static device_method_t blake2_methods[] = {
        DEVMETHOD(device_identify, blake2_identify),
        DEVMETHOD(device_probe, blake2_probe),
        DEVMETHOD(device_attach, blake2_attach),
        DEVMETHOD(device_detach, blake2_detach),

        DEVMETHOD(cryptodev_probesession, blake2_probesession),
        DEVMETHOD(cryptodev_newsession, blake2_newsession),
        DEVMETHOD(cryptodev_process, blake2_process),

        DEVMETHOD_END
};

static driver_t blake2_driver = {
        "blaketwo",
        blake2_methods,
        sizeof(struct blake2_softc),
};

DRIVER_MODULE(blake2, nexus, blake2_driver, 0, 0);
MODULE_VERSION(blake2, 1);
MODULE_DEPEND(blake2, crypto, 1, 1, 1);

static bool
blake2_check_klen(const struct crypto_session_params *csp, unsigned klen)
{

        if (csp->csp_auth_alg == CRYPTO_BLAKE2S)
                return (klen <= BLAKE2S_KEYBYTES);
        else
                return (klen <= BLAKE2B_KEYBYTES);
}

static int
blake2_cipher_setup(struct blake2_session *ses,
    const struct crypto_session_params *csp)
{
        int hashlen;

        CTASSERT((size_t)BLAKE2S_OUTBYTES <= (size_t)BLAKE2B_OUTBYTES);

        if (!blake2_check_klen(csp, csp->csp_auth_klen))
                return (EINVAL);

        if (csp->csp_auth_mlen < 0)
                return (EINVAL);

        switch (csp->csp_auth_alg) {
        case CRYPTO_BLAKE2S:
                hashlen = BLAKE2S_OUTBYTES;
                break;
        case CRYPTO_BLAKE2B:
                hashlen = BLAKE2B_OUTBYTES;
                break;
        default:
                return (EINVAL);
        }

        if (csp->csp_auth_mlen > hashlen)
                return (EINVAL);

        if (csp->csp_auth_mlen == 0)
                ses->mlen = hashlen;
        else
                ses->mlen = csp->csp_auth_mlen;
        return (0);
}

static int
blake2b_applicator(void *state, const void *buf, u_int len)
{
        int rc;

        rc = blake2b_update(state, buf, len);
        if (rc != 0)
                return (EINVAL);
        return (0);
}

static int
blake2s_applicator(void *state, const void *buf, u_int len)
{
        int rc;

        rc = blake2s_update(state, buf, len);
        if (rc != 0)
                return (EINVAL);
        return (0);
}

static int
blake2_cipher_process(struct blake2_session *ses, struct cryptop *crp)
{
        union {
                blake2b_state sb;
                blake2s_state ss;
        } bctx;
        char res[BLAKE2B_OUTBYTES], res2[BLAKE2B_OUTBYTES];
        const struct crypto_session_params *csp;
        const void *key;
        int error, rc;
        unsigned klen;

        csp = crypto_get_params(crp->crp_session);
        if (crp->crp_auth_key != NULL)
                key = crp->crp_auth_key;
        else
                key = csp->csp_auth_key;
        klen = csp->csp_auth_klen;

        fpu_kern_enter(curthread, NULL, FPU_KERN_NORMAL | FPU_KERN_NOCTX);

        switch (csp->csp_auth_alg) {
        case CRYPTO_BLAKE2B:
                if (klen > 0)
                        rc = blake2b_init_key(&bctx.sb, ses->mlen, key, klen);
                else
                        rc = blake2b_init(&bctx.sb, ses->mlen);
                if (rc != 0) {
                        error = EINVAL;
                        break;
                }
                error = crypto_apply(crp, crp->crp_payload_start,
                    crp->crp_payload_length, blake2b_applicator, &bctx.sb);
                if (error != 0)
                        break;
                rc = blake2b_final(&bctx.sb, res, ses->mlen);
                if (rc != 0)
                        error = EINVAL;
                break;
        case CRYPTO_BLAKE2S:
                if (klen > 0)
                        rc = blake2s_init_key(&bctx.ss, ses->mlen, key, klen);
                else
                        rc = blake2s_init(&bctx.ss, ses->mlen);
                if (rc != 0) {
                        error = EINVAL;
                        break;
                }
                error = crypto_apply(crp, crp->crp_payload_start,
                    crp->crp_payload_length, blake2s_applicator, &bctx.ss);
                if (error != 0)
                        break;
                rc = blake2s_final(&bctx.ss, res, ses->mlen);
                if (rc != 0)
                        error = EINVAL;
                break;
        default:
                __assert_unreachable();
        }

        fpu_kern_leave(curthread, NULL);

        if (error != 0)
                return (error);

        if (crp->crp_op & CRYPTO_OP_VERIFY_DIGEST) {
                crypto_copydata(crp, crp->crp_digest_start, ses->mlen, res2);
                if (timingsafe_bcmp(res, res2, ses->mlen) != 0)
                        error = EBADMSG;
        } else
                crypto_copyback(crp, crp->crp_digest_start, ses->mlen, res);

        return (error);
}