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Up until now algorithms have been happy to get a context pointer since they know everything that's in the tfm already (e.g., alignment, block size). However, once we have parameterised algorithms, such information will be specific to each tfm. So the algorithm API needs to be changed to pass the tfm structure instead of the context pointer. This patch is basically a text substitution. The only tricky bit is the assembly routines that need to get the context pointer offset through asm-offsets.h. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
113 lines
2.5 KiB
C
113 lines
2.5 KiB
C
/*
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* Cryptographic API.
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*
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* CRC32C chksum
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*
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* This module file is a wrapper to invoke the lib/crc32c routines.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the Free
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* Software Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*
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*/
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/string.h>
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#include <linux/crypto.h>
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#include <linux/crc32c.h>
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#include <linux/types.h>
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#include <asm/byteorder.h>
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#define CHKSUM_BLOCK_SIZE 32
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#define CHKSUM_DIGEST_SIZE 4
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struct chksum_ctx {
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u32 crc;
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};
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/*
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* Steps through buffer one byte at at time, calculates reflected
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* crc using table.
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*/
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static void chksum_init(struct crypto_tfm *tfm)
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{
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struct chksum_ctx *mctx = crypto_tfm_ctx(tfm);
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mctx->crc = ~(u32)0; /* common usage */
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}
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/*
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* Setting the seed allows arbitrary accumulators and flexible XOR policy
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* If your algorithm starts with ~0, then XOR with ~0 before you set
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* the seed.
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*/
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static int chksum_setkey(struct crypto_tfm *tfm, const u8 *key,
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unsigned int keylen, u32 *flags)
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{
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struct chksum_ctx *mctx = crypto_tfm_ctx(tfm);
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if (keylen != sizeof(mctx->crc)) {
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if (flags)
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*flags = CRYPTO_TFM_RES_BAD_KEY_LEN;
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return -EINVAL;
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}
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mctx->crc = __cpu_to_le32(*(u32 *)key);
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return 0;
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}
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static void chksum_update(struct crypto_tfm *tfm, const u8 *data,
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unsigned int length)
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{
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struct chksum_ctx *mctx = crypto_tfm_ctx(tfm);
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u32 mcrc;
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mcrc = crc32c(mctx->crc, data, (size_t)length);
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mctx->crc = mcrc;
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}
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static void chksum_final(struct crypto_tfm *tfm, u8 *out)
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{
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struct chksum_ctx *mctx = crypto_tfm_ctx(tfm);
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u32 mcrc = (mctx->crc ^ ~(u32)0);
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*(u32 *)out = __le32_to_cpu(mcrc);
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}
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static struct crypto_alg alg = {
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.cra_name = "crc32c",
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.cra_flags = CRYPTO_ALG_TYPE_DIGEST,
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.cra_blocksize = CHKSUM_BLOCK_SIZE,
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.cra_ctxsize = sizeof(struct chksum_ctx),
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.cra_module = THIS_MODULE,
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.cra_list = LIST_HEAD_INIT(alg.cra_list),
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.cra_u = {
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.digest = {
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.dia_digestsize= CHKSUM_DIGEST_SIZE,
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.dia_setkey = chksum_setkey,
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.dia_init = chksum_init,
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.dia_update = chksum_update,
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.dia_final = chksum_final
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}
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}
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};
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static int __init init(void)
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{
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return crypto_register_alg(&alg);
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}
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static void __exit fini(void)
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{
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crypto_unregister_alg(&alg);
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}
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module_init(init);
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module_exit(fini);
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MODULE_AUTHOR("Clay Haapala <chaapala@cisco.com>");
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MODULE_DESCRIPTION("CRC32c (Castagnoli) calculations wrapper for lib/crc32c");
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MODULE_LICENSE("GPL");
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