/*-
 * 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/cdefs.h>
#include <sys/param.h>
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/kobj.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <sys/rwlock.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 {
	bool	dying;
	int32_t cid;
	struct rwlock lock;
};

static struct mtx_padalign *ctx_mtx;
static struct fpu_kern_ctx **ctx_fpu;

#define ACQUIRE_CTX(i, ctx)					\
	do {							\
		(i) = PCPU_GET(cpuid);				\
		mtx_lock(&ctx_mtx[(i)]);			\
		(ctx) = ctx_fpu[(i)];				\
	} while (0)
#define RELEASE_CTX(i, ctx)					\
	do {							\
		mtx_unlock(&ctx_mtx[(i)]);			\
		(i) = -1;					\
		(ctx) = NULL;					\
	} while (0)

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", -1) == NULL &&
	    BUS_ADD_CHILD(parent, 10, "blaketwo", -1) == 0)
		panic("blaketwo: could not attach");
}

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

static void
blake2_cleanctx(void)
{
	int i;

	/* XXX - no way to return driverid */
	CPU_FOREACH(i) {
		if (ctx_fpu[i] != NULL) {
			mtx_destroy(&ctx_mtx[i]);
			fpu_kern_free_ctx(ctx_fpu[i]);
		}
		ctx_fpu[i] = NULL;
	}
	free(ctx_mtx, M_BLAKE2);
	ctx_mtx = NULL;
	free(ctx_fpu, M_BLAKE2);
	ctx_fpu = NULL;
}

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

	sc = device_get_softc(dev);
	sc->dying = false;

	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);
	}

	ctx_mtx = malloc(sizeof(*ctx_mtx) * (mp_maxid + 1), M_BLAKE2,
	    M_WAITOK | M_ZERO);
	ctx_fpu = malloc(sizeof(*ctx_fpu) * (mp_maxid + 1), M_BLAKE2,
	    M_WAITOK | M_ZERO);

	CPU_FOREACH(i) {
#ifdef __amd64__
		ctx_fpu[i] = fpu_kern_alloc_ctx_domain(
		    pcpu_find(i)->pc_domain, FPU_KERN_NORMAL);
#else
		ctx_fpu[i] = fpu_kern_alloc_ctx(FPU_KERN_NORMAL);
#endif
		mtx_init(&ctx_mtx[i], "bl2fpumtx", NULL, MTX_DEF | MTX_NEW);
	}

	rw_init(&sc->lock, "blake2_lock");

	return (0);
}

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

	sc = device_get_softc(dev);

	rw_wlock(&sc->lock);
	sc->dying = true;
	rw_wunlock(&sc->lock);
	crypto_unregister_all(sc->cid);

	rw_destroy(&sc->lock);

	blake2_cleanctx();

	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_softc *sc;
	struct blake2_session *ses;
	int error;

	sc = device_get_softc(dev);

	ses = crypto_get_driver_session(cses);

	rw_rlock(&sc->lock);
	if (sc->dying) {
		rw_runlock(&sc->lock);
		return (EINVAL);
	}
	rw_runlock(&sc->lock);

	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),
};
static devclass_t blake2_devclass;

DRIVER_MODULE(blake2, nexus, blake2_driver, blake2_devclass, 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;
	struct fpu_kern_ctx *ctx;
	const void *key;
	int ctxidx;
	bool kt;
	int error, rc;
	unsigned klen;

	ctx = NULL;
	ctxidx = 0;
	error = EINVAL;

	kt = is_fpu_kern_thread(0);
	if (!kt) {
		ACQUIRE_CTX(ctxidx, ctx);
		fpu_kern_enter(curthread, ctx,
		    FPU_KERN_NORMAL | FPU_KERN_KTHR);
	}

	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;
	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)
			goto out;
		error = crypto_apply(crp, crp->crp_payload_start,
		    crp->crp_payload_length, blake2b_applicator, &bctx.sb);
		if (error != 0)
			goto out;
		rc = blake2b_final(&bctx.sb, res, ses->mlen);
		if (rc != 0) {
			error = EINVAL;
			goto out;
		}
		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)
			goto out;
		error = crypto_apply(crp, crp->crp_payload_start,
		    crp->crp_payload_length, blake2s_applicator, &bctx.ss);
		if (error != 0)
			goto out;
		rc = blake2s_final(&bctx.ss, res, ses->mlen);
		if (rc != 0) {
			error = EINVAL;
			goto out;
		}
		break;
	default:
		panic("unreachable");
	}

	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)
			return (EBADMSG);
	} else
		crypto_copyback(crp, crp->crp_digest_start, ses->mlen, res);

out:
	if (!kt) {
		fpu_kern_leave(curthread, ctx);
		RELEASE_CTX(ctxidx, ctx);
	}
	return (error);
}