/*  * Cryptographic API. * * Null algorithms, aka Much Ado About Nothing. * * These are needed for IPsec, and may be useful in general for * testing & debugging. *  * The null cipher is compliant with RFC2410. * * Copyright (c) 2002 James Morris <jmorris@intercode.com.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 <linux/init.h>#include <linux/module.h>#include <linux/mm.h>#include <asm/scatterlist.h>#include <linux/crypto.h>#include <linux/string.h> #define NULL_KEY_SIZE		0#define NULL_BLOCK_SIZE		1#define NULL_DIGEST_SIZE	0 static int null_compress(void *ctx, const u8 *src, unsigned int slen,                         u8 *dst, unsigned int *dlen){	if (slen > *dlen)		return -EINVAL;	memcpy(dst, src, slen);	*dlen = slen;	return 0;} static void null_init(void *ctx){ } static void null_update(void *ctx, const u8 *data, unsigned int len){ } static void null_final(void *ctx, u8 *out){ } static int null_setkey(void *ctx, const u8 *key,                       unsigned int keylen, u32 *flags){ return 0; } static void null_crypt(void *ctx, u8 *dst, const u8 *src){	memcpy(dst, src, NULL_BLOCK_SIZE);} static struct crypto_alg compress_null = {	.cra_name		=	"compress_null",	.cra_flags		=	CRYPTO_ALG_TYPE_COMPRESS,	.cra_blocksize		=	NULL_BLOCK_SIZE,	.cra_ctxsize		=	0,	.cra_module		=	THIS_MODULE,	.cra_list		=       LIST_HEAD_INIT(compress_null.cra_list),	.cra_u			=	{ .compress = {	.coa_compress 		=	null_compress,	.coa_decompress		=	null_compress } }}; static struct crypto_alg digest_null = {	.cra_name		=	"digest_null",	.cra_flags		=	CRYPTO_ALG_TYPE_DIGEST,	.cra_blocksize		=	NULL_BLOCK_SIZE,	.cra_ctxsize		=	0,	.cra_module		=	THIS_MODULE,	.cra_list		=       LIST_HEAD_INIT(digest_null.cra_list),		.cra_u			=	{ .digest = {	.dia_digestsize		=	NULL_DIGEST_SIZE,	.dia_init   		=	null_init,	.dia_update 		=	null_update,	.dia_final  		=	null_final } }}; static struct crypto_alg cipher_null = {	.cra_name		=	"cipher_null",	.cra_flags		=	CRYPTO_ALG_TYPE_CIPHER,	.cra_blocksize		=	NULL_BLOCK_SIZE,	.cra_ctxsize		=	0,	.cra_module		=	THIS_MODULE,	.cra_list		=	LIST_HEAD_INIT(cipher_null.cra_list),	.cra_u			=	{ .cipher = {	.cia_min_keysize	=	NULL_KEY_SIZE,	.cia_max_keysize	=	NULL_KEY_SIZE,	.cia_setkey		= 	null_setkey,	.cia_encrypt		=	null_crypt,	.cia_decrypt		=	null_crypt } }}; MODULE_ALIAS("compress_null");MODULE_ALIAS("digest_null");MODULE_ALIAS("cipher_null"); static int __init init(void){	int ret = 0;		ret = crypto_register_alg(&cipher_null);	if (ret < 0)		goto out; 	ret = crypto_register_alg(&digest_null);	if (ret < 0) {		crypto_unregister_alg(&cipher_null);		goto out;	} 	ret = crypto_register_alg(&compress_null);	if (ret < 0) {		crypto_unregister_alg(&digest_null);		crypto_unregister_alg(&cipher_null);		goto out;	} out:		return ret;} static void __exit fini(void){	crypto_unregister_alg(&compress_null);	crypto_unregister_alg(&digest_null);	crypto_unregister_alg(&cipher_null);} module_init(init);module_exit(fini); MODULE_LICENSE("GPL");MODULE_DESCRIPTION("Null Cryptographic Algorithms");