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/*

 * ECB: Electronic CodeBook mode

 *

 * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>

 *

 * 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 <crypto/algapi.h>

#include <linux/err.h>

#include <linux/init.h>

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/scatterlist.h>

#include <linux/slab.h>

struct crypto_ecb_ctx {

        struct crypto_cipher *child;

};

static int crypto_ecb_setkey(struct crypto_tfm *parent, const u8 *key,

                             unsigned int keylen)

{

        struct crypto_ecb_ctx *ctx = crypto_tfm_ctx(parent);

        struct crypto_cipher *child = ctx->child;

        int err;

        crypto_cipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);

        crypto_cipher_set_flags(child, crypto_tfm_get_flags(parent) &

                                       CRYPTO_TFM_REQ_MASK);

        err = crypto_cipher_setkey(child, key, keylen);

        crypto_tfm_set_flags(parent, crypto_cipher_get_flags(child) &

                                     CRYPTO_TFM_RES_MASK);

        return err;

}

static int crypto_ecb_crypt(struct blkcipher_desc *desc,

                            struct blkcipher_walk *walk,

                            struct crypto_cipher *tfm,

                            void (*fn)(struct crypto_tfm *, u8 *, const u8 *))

{

        int bsize = crypto_cipher_blocksize(tfm);

        unsigned int nbytes;

        int err;

        err = blkcipher_walk_virt(desc, walk);

        while ((nbytes = walk->nbytes)) {

                u8 *wsrc = walk->src.virt.addr;

                u8 *wdst = walk->dst.virt.addr;

                do {

                        fn(crypto_cipher_tfm(tfm), wdst, wsrc);

                        wsrc += bsize;

                        wdst += bsize;

                } while ((nbytes -= bsize) >= bsize);

                err = blkcipher_walk_done(desc, walk, nbytes);

        }

        return err;

}

static int crypto_ecb_encrypt(struct blkcipher_desc *desc,

                              struct scatterlist *dst, struct scatterlist *src,

                              unsigned int nbytes)

{

        struct blkcipher_walk walk;

        struct crypto_blkcipher *tfm = desc->tfm;

        struct crypto_ecb_ctx *ctx = crypto_blkcipher_ctx(tfm);

        struct crypto_cipher *child = ctx->child;

        blkcipher_walk_init(&walk, dst, src, nbytes);

        return crypto_ecb_crypt(desc, &walk, child,

                                crypto_cipher_alg(child)->cia_encrypt);

}

static int crypto_ecb_decrypt(struct blkcipher_desc *desc,

                              struct scatterlist *dst, struct scatterlist *src,

                              unsigned int nbytes)

{

        struct blkcipher_walk walk;

        struct crypto_blkcipher *tfm = desc->tfm;

        struct crypto_ecb_ctx *ctx = crypto_blkcipher_ctx(tfm);

        struct crypto_cipher *child = ctx->child;

        blkcipher_walk_init(&walk, dst, src, nbytes);

        return crypto_ecb_crypt(desc, &walk, child,

                                crypto_cipher_alg(child)->cia_decrypt);

}

static int crypto_ecb_init_tfm(struct crypto_tfm *tfm)

{

        struct crypto_instance *inst = (void *)tfm->__crt_alg;

        struct crypto_spawn *spawn = crypto_instance_ctx(inst);

        struct crypto_ecb_ctx *ctx = crypto_tfm_ctx(tfm);

        struct crypto_cipher *cipher;

        cipher = crypto_spawn_cipher(spawn);

        if (IS_ERR(cipher))

                return PTR_ERR(cipher);

        ctx->child = cipher;

        return 0;

}

static void crypto_ecb_exit_tfm(struct crypto_tfm *tfm)

{

        struct crypto_ecb_ctx *ctx = crypto_tfm_ctx(tfm);

        crypto_free_cipher(ctx->child);

}

static struct crypto_instance *crypto_ecb_alloc(struct rtattr **tb)

{

        struct crypto_instance *inst;

        struct crypto_alg *alg;

        int err;

        err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_BLKCIPHER);

        if (err)

                return ERR_PTR(err);

        alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER,

                                  CRYPTO_ALG_TYPE_MASK);

        if (IS_ERR(alg))

                return ERR_PTR(PTR_ERR(alg));

        inst = crypto_alloc_instance("ecb", alg);

        if (IS_ERR(inst))

                goto out_put_alg;

        inst->alg.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER;

        inst->alg.cra_priority = alg->cra_priority;

        inst->alg.cra_blocksize = alg->cra_blocksize;

        inst->alg.cra_alignmask = alg->cra_alignmask;

        inst->alg.cra_type = &crypto_blkcipher_type;

        inst->alg.cra_blkcipher.min_keysize = alg->cra_cipher.cia_min_keysize;

        inst->alg.cra_blkcipher.max_keysize = alg->cra_cipher.cia_max_keysize;

        inst->alg.cra_ctxsize = sizeof(struct crypto_ecb_ctx);

        inst->alg.cra_init = crypto_ecb_init_tfm;

        inst->alg.cra_exit = crypto_ecb_exit_tfm;

        inst->alg.cra_blkcipher.setkey = crypto_ecb_setkey;

        inst->alg.cra_blkcipher.encrypt = crypto_ecb_encrypt;

        inst->alg.cra_blkcipher.decrypt = crypto_ecb_decrypt;

out_put_alg:

        crypto_mod_put(alg);

        return inst;

}

static void crypto_ecb_free(struct crypto_instance *inst)

{

        crypto_drop_spawn(crypto_instance_ctx(inst));

        kfree(inst);

}

static struct crypto_template crypto_ecb_tmpl = {

        .name = "ecb",

        .alloc = crypto_ecb_alloc,

        .free = crypto_ecb_free,

        .module = THIS_MODULE,

};

static int __init crypto_ecb_module_init(void)

{

        return crypto_register_template(&crypto_ecb_tmpl);

}

static void __exit crypto_ecb_module_exit(void)

{

        crypto_unregister_template(&crypto_ecb_tmpl);

}

module_init(crypto_ecb_module_init);

module_exit(crypto_ecb_module_exit);

MODULE_LICENSE("GPL");

MODULE_DESCRIPTION("ECB block cipher algorithm");