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/*
* Glue code for optimized assembly version of Salsa20.
*
* Copyright (c) 2007 Tan Swee Heng <thesweeheng@gmail.com>
*
* The assembly codes are public domain assembly codes written by Daniel. J.
* Bernstein <djb@cr.yp.to>. The codes are modified to include indentation
* and to remove extraneous comments and functions that are not needed.
* - i586 version, renamed as salsa20-i586-asm_32.S
* available from <http://cr.yp.to/snuffle/salsa20/x86-pm/salsa20.s>
* - x86-64 version, renamed as salsa20-x86_64-asm_64.S
* available from <http://cr.yp.to/snuffle/salsa20/amd64-3/salsa20.s>
*
* Also modified to set up the initial state using the generic C code rather
* than in assembly.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at your option)
* any later version.
*
*/
#include <asm/unaligned.h>
#include <crypto/internal/skcipher.h>
#include <crypto/salsa20.h>
#include <linux/module.h>
asmlinkage void salsa20_encrypt_bytes(u32 state[16], const u8 *src, u8 *dst,
u32 bytes);
static int salsa20_asm_crypt(struct skcipher_request *req)
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
const struct salsa20_ctx *ctx = crypto_skcipher_ctx(tfm);
struct skcipher_walk walk;
u32 state[16];
int err;
err = skcipher_walk_virt(&walk, req, true);
crypto_salsa20_init(state, ctx, walk.iv);
while (walk.nbytes > 0) {
unsigned int nbytes = walk.nbytes;
if (nbytes < walk.total)
nbytes = round_down(nbytes, walk.stride);
salsa20_encrypt_bytes(state, walk.src.virt.addr,
walk.dst.virt.addr, nbytes);
err = skcipher_walk_done(&walk, walk.nbytes - nbytes);
}
return err;
}
static struct skcipher_alg alg = {
.base.cra_name = "salsa20",
.base.cra_driver_name = "salsa20-asm",
.base.cra_priority = 200,
.base.cra_blocksize = 1,
.base.cra_ctxsize = sizeof(struct salsa20_ctx),
.base.cra_module = THIS_MODULE,
.min_keysize = SALSA20_MIN_KEY_SIZE,
.max_keysize = SALSA20_MAX_KEY_SIZE,
.ivsize = SALSA20_IV_SIZE,
.chunksize = SALSA20_BLOCK_SIZE,
.setkey = crypto_salsa20_setkey,
.encrypt = salsa20_asm_crypt,
.decrypt = salsa20_asm_crypt,
};
static int __init init(void)
{
return crypto_register_skcipher(&alg);
}
static void __exit fini(void)
{
crypto_unregister_skcipher(&alg);
}
module_init(init);
module_exit(fini);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION ("Salsa20 stream cipher algorithm (optimized assembly version)");
MODULE_ALIAS_CRYPTO("salsa20");
MODULE_ALIAS_CRYPTO("salsa20-asm");
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