/*-
 * Copyright (c) 2014 The FreeBSD Foundation
 *
 * This software was developed by John-Mark Gurney under
 * the sponsorship of the FreeBSD Foundation and
 * Rubicon Communications, LLC (Netgate).
 * 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 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 AUTHOR 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/types.h>
#include <sys/systm.h>
#include <opencrypto/gfmult.h>
#include <opencrypto/gmac.h>

void
AES_GMAC_Init(void *ctx)
{
        struct aes_gmac_ctx *agc;

        agc = ctx;
        bzero(agc, sizeof *agc);
}

void
AES_GMAC_Setkey(void *ctx, const uint8_t *key, u_int klen)
{
        struct aes_gmac_ctx *agc;
        const uint8_t zeros[GMAC_BLOCK_LEN] = {};
        struct gf128 h;
        uint8_t hbuf[GMAC_BLOCK_LEN];

        agc = ctx;
        agc->rounds = rijndaelKeySetupEnc(agc->keysched, key, klen * 8);

        rijndaelEncrypt(agc->keysched, agc->rounds, zeros, hbuf);

        h = gf128_read(hbuf);
        gf128_genmultable4(h, &agc->ghashtbl);

        explicit_bzero(&h, sizeof h);
        explicit_bzero(hbuf, sizeof hbuf);
}

void
AES_GMAC_Reinit(void *ctx, const uint8_t *iv, u_int ivlen)
{
        struct aes_gmac_ctx *agc;

        agc = ctx;
        KASSERT(ivlen <= sizeof agc->counter, ("passed ivlen too large!"));
        memset(agc->counter, 0, sizeof(agc->counter));
        bcopy(iv, agc->counter, ivlen);
        agc->counter[GMAC_BLOCK_LEN - 1] = 1;

        memset(&agc->hash, 0, sizeof(agc->hash));
}

int
AES_GMAC_Update(void *ctx, const void *vdata, u_int len)
{
        struct aes_gmac_ctx *agc;
        const uint8_t *data;
        struct gf128 v;
        uint8_t buf[GMAC_BLOCK_LEN] = {};
        int i;

        agc = ctx;
        data = vdata;
        v = agc->hash;

        while (len > 0) {
                if (len >= 4*GMAC_BLOCK_LEN) {
                        i = 4*GMAC_BLOCK_LEN;
                        v = gf128_mul4b(v, data, &agc->ghashtbl);
                } else if (len >= GMAC_BLOCK_LEN) {
                        i = GMAC_BLOCK_LEN;
                        v = gf128_add(v, gf128_read(data));
                        v = gf128_mul(v, &agc->ghashtbl.tbls[0]);
                } else {
                        i = len;
                        bcopy(data, buf, i);
                        v = gf128_add(v, gf128_read(&buf[0]));
                        v = gf128_mul(v, &agc->ghashtbl.tbls[0]);
                        explicit_bzero(buf, sizeof buf);
                }
                len -= i;
                data += i;
        }

        agc->hash = v;
        explicit_bzero(&v, sizeof v);

        return (0);
}

void
AES_GMAC_Final(uint8_t *digest, void *ctx)
{
        struct aes_gmac_ctx *agc;
        uint8_t enccntr[GMAC_BLOCK_LEN];
        struct gf128 a;

        agc = ctx;

        rijndaelEncrypt(agc->keysched, agc->rounds, agc->counter, enccntr);
        a = gf128_add(agc->hash, gf128_read(enccntr));
        gf128_write(a, digest);

        explicit_bzero(enccntr, sizeof enccntr);
}