/* This file is in the public domain. */

#include <sys/cdefs.h>
#include <crypto/chacha20/chacha.h>
#include <opencrypto/xform_enc.h>

static int
chacha20_xform_setkey(void *ctx, const uint8_t *key, int len)
{

        if (len != CHACHA_MINKEYLEN && len != 32)
                return (EINVAL);

        chacha_keysetup(ctx, key, len * 8);
        return (0);
}

static void
chacha20_xform_reinit(void *ctx, const uint8_t *iv, size_t ivlen)
{
        KASSERT(ivlen == CHACHA_NONCELEN + CHACHA_CTRLEN,
            ("%s: invalid IV length", __func__));
        chacha_ivsetup(ctx, iv + 8, iv);
}

static void
chacha20_xform_crypt(void *ctx, const uint8_t *in, uint8_t *out)
{

        chacha_encrypt_bytes(ctx, in, out, CHACHA_BLOCKLEN);
}

static void
chacha20_xform_crypt_multi(void *ctx, const uint8_t *in, uint8_t *out,
    size_t len)
{
        KASSERT(len % CHACHA_BLOCKLEN == 0, ("%s: invalid length", __func__));
        chacha_encrypt_bytes(ctx, in, out, len);
}

static void
chacha20_xform_crypt_last(void *ctx, const uint8_t *in, uint8_t *out,
    size_t len)
{

        chacha_encrypt_bytes(ctx, in, out, len);
}

const struct enc_xform enc_xform_chacha20 = {
        .type = CRYPTO_CHACHA20,
        .name = "chacha20",
        .ctxsize = sizeof(struct chacha_ctx),
        .blocksize = 1,
        .native_blocksize = CHACHA_BLOCKLEN,
        .ivsize = CHACHA_NONCELEN + CHACHA_CTRLEN,
        .minkey = CHACHA_MINKEYLEN,
        .maxkey = 32,
        .setkey = chacha20_xform_setkey,
        .reinit = chacha20_xform_reinit,
        .encrypt = chacha20_xform_crypt,
        .decrypt = chacha20_xform_crypt,
        .encrypt_multi = chacha20_xform_crypt_multi,
        .decrypt_multi = chacha20_xform_crypt_multi,
        .encrypt_last = chacha20_xform_crypt_last,
        .decrypt_last = chacha20_xform_crypt_last,
};