/* GPL HEADER START
 *
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 only,
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License version 2 for more details (a copy is included
 * in the LICENSE file that accompanied this code).
 *
 * You should have received a copy of the GNU General Public License
 * version 2 along with this program; If not, see http://www.gnu.org/licenses
 *
 * Please  visit http://www.xyratex.com/contact if you need additional
 * information or have any questions.
 *
 * GPL HEADER END
 */

/*
 * Copyright 2012 Xyratex Technology Limited
 *
 * Copyright (c) 2012, Intel Corporation.
 */

#include <linux/crypto.h>
#include <linux/scatterlist.h>
#include "../../../include/linux/libcfs/libcfs.h"
#include "linux-crypto.h"
/**
 *  Array of  hash algorithm speed in MByte per second
 */
static int cfs_crypto_hash_speeds[CFS_HASH_ALG_MAX];



static int cfs_crypto_hash_alloc(unsigned char alg_id,
                                 const struct cfs_crypto_hash_type **type,
                                 struct hash_desc *desc, unsigned char *key,
                                 unsigned int key_len)
{
        int     err = 0;

        *type = cfs_crypto_hash_type(alg_id);

        if (*type == NULL) {
                CWARN("Unsupported hash algorithm id = %d, max id is %d\n",
                      alg_id, CFS_HASH_ALG_MAX);
                return -EINVAL;
        }
        desc->tfm = crypto_alloc_hash((*type)->cht_name, 0, 0);

        if (desc->tfm == NULL)
                return -EINVAL;

        if (IS_ERR(desc->tfm)) {
                CDEBUG(D_INFO, "Failed to alloc crypto hash %s\n",
                       (*type)->cht_name);
                return PTR_ERR(desc->tfm);
        }

        desc->flags = 0;

        /** Shash have different logic for initialization then digest
         * shash: crypto_hash_setkey, crypto_hash_init
         * digest: crypto_digest_init, crypto_digest_setkey
         * Skip this function for digest, because we use shash logic at
         * cfs_crypto_hash_alloc.
         */
        if (key != NULL) {
                err = crypto_hash_setkey(desc->tfm, key, key_len);
        } else if ((*type)->cht_key != 0) {
                err = crypto_hash_setkey(desc->tfm,
                                         (unsigned char *)&((*type)->cht_key),
                                         (*type)->cht_size);
        }

        if (err != 0) {
                crypto_free_hash(desc->tfm);
                return err;
        }

        CDEBUG(D_INFO, "Using crypto hash: %s (%s) speed %d MB/s\n",
               (crypto_hash_tfm(desc->tfm))->__crt_alg->cra_name,
               (crypto_hash_tfm(desc->tfm))->__crt_alg->cra_driver_name,
               cfs_crypto_hash_speeds[alg_id]);

        return crypto_hash_init(desc);
}

int cfs_crypto_hash_digest(unsigned char alg_id,
                           const void *buf, unsigned int buf_len,
                           unsigned char *key, unsigned int key_len,
                           unsigned char *hash, unsigned int *hash_len)
{
        struct scatterlist      sl;
        struct hash_desc        hdesc;
        int                     err;
        const struct cfs_crypto_hash_type       *type;

        if (buf == NULL || buf_len == 0 || hash_len == NULL)
                return -EINVAL;

        err = cfs_crypto_hash_alloc(alg_id, &type, &hdesc, key, key_len);
        if (err != 0)
                return err;

        if (hash == NULL || *hash_len < type->cht_size) {
                *hash_len = type->cht_size;
                crypto_free_hash(hdesc.tfm);
                return -ENOSPC;
        }
        sg_init_one(&sl, (void *)buf, buf_len);

        hdesc.flags = 0;
        err = crypto_hash_digest(&hdesc, &sl, sl.length, hash);
        crypto_free_hash(hdesc.tfm);

        return err;
}
EXPORT_SYMBOL(cfs_crypto_hash_digest);

struct cfs_crypto_hash_desc *
        cfs_crypto_hash_init(unsigned char alg_id,
                             unsigned char *key, unsigned int key_len)
{

        struct  hash_desc       *hdesc;
        int                  err;
        const struct cfs_crypto_hash_type       *type;

        hdesc = kmalloc(sizeof(*hdesc), 0);
        if (hdesc == NULL)
                return ERR_PTR(-ENOMEM);

        err = cfs_crypto_hash_alloc(alg_id, &type, hdesc, key, key_len);

        if (err) {
                kfree(hdesc);
                return ERR_PTR(err);
        }
        return (struct cfs_crypto_hash_desc *)hdesc;
}
EXPORT_SYMBOL(cfs_crypto_hash_init);

int cfs_crypto_hash_update_page(struct cfs_crypto_hash_desc *hdesc,
                                struct page *page, unsigned int offset,
                                unsigned int len)
{
        struct scatterlist sl;

        sg_init_table(&sl, 1);
        sg_set_page(&sl, page, len, offset & ~CFS_PAGE_MASK);

        return crypto_hash_update((struct hash_desc *)hdesc, &sl, sl.length);
}
EXPORT_SYMBOL(cfs_crypto_hash_update_page);

int cfs_crypto_hash_update(struct cfs_crypto_hash_desc *hdesc,
                           const void *buf, unsigned int buf_len)
{
        struct scatterlist sl;

        sg_init_one(&sl, (void *)buf, buf_len);

        return crypto_hash_update((struct hash_desc *)hdesc, &sl, sl.length);
}
EXPORT_SYMBOL(cfs_crypto_hash_update);

/*      If hash_len pointer is NULL - destroy descriptor. */
int cfs_crypto_hash_final(struct cfs_crypto_hash_desc *hdesc,
                          unsigned char *hash, unsigned int *hash_len)
{
        int     err;
        int     size = crypto_hash_digestsize(((struct hash_desc *)hdesc)->tfm);

        if (hash_len == NULL) {
                crypto_free_hash(((struct hash_desc *)hdesc)->tfm);
                kfree(hdesc);
                return 0;
        }
        if (hash == NULL || *hash_len < size) {
                *hash_len = size;
                return -ENOSPC;
        }
        err = crypto_hash_final((struct hash_desc *) hdesc, hash);

        if (err < 0) {
                /* May be caller can fix error */
                return err;
        }
        crypto_free_hash(((struct hash_desc *)hdesc)->tfm);
        kfree(hdesc);
        return err;
}
EXPORT_SYMBOL(cfs_crypto_hash_final);

static void cfs_crypto_performance_test(unsigned char alg_id,
                                        const unsigned char *buf,
                                        unsigned int buf_len)
{
        unsigned long              start, end;
        int                          bcount, err = 0;
        int                          sec = 1; /* do test only 1 sec */
        unsigned char              hash[64];
        unsigned int                hash_len = 64;

        for (start = jiffies, end = start + sec * HZ, bcount = 0;
             time_before(jiffies, end); bcount++) {
                err = cfs_crypto_hash_digest(alg_id, buf, buf_len, NULL, 0,
                                             hash, &hash_len);
                if (err)
                        break;

        }
        end = jiffies;

        if (err) {
                cfs_crypto_hash_speeds[alg_id] =  -1;
                CDEBUG(D_INFO, "Crypto hash algorithm %s, err = %d\n",
                       cfs_crypto_hash_name(alg_id), err);
        } else {
                unsigned long   tmp;
                tmp = ((bcount * buf_len / jiffies_to_msecs(end - start)) *
                       1000) / (1024 * 1024);
                cfs_crypto_hash_speeds[alg_id] = (int)tmp;
        }
        CDEBUG(D_INFO, "Crypto hash algorithm %s speed = %d MB/s\n",
               cfs_crypto_hash_name(alg_id), cfs_crypto_hash_speeds[alg_id]);
}

int cfs_crypto_hash_speed(unsigned char hash_alg)
{
        if (hash_alg < CFS_HASH_ALG_MAX)
                return cfs_crypto_hash_speeds[hash_alg];
        else
                return -1;
}
EXPORT_SYMBOL(cfs_crypto_hash_speed);

/**
 * Do performance test for all hash algorithms.
 */
static int cfs_crypto_test_hashes(void)
{
        unsigned char      i;
        unsigned char      *data;
        unsigned int        j;
        /* Data block size for testing hash. Maximum
         * kmalloc size for 2.6.18 kernel is 128K */
        unsigned int        data_len = 1 * 128 * 1024;

        data = kmalloc(data_len, 0);
        if (data == NULL) {
                CERROR("Failed to allocate mem\n");
                return -ENOMEM;
        }

        for (j = 0; j < data_len; j++)
                data[j] = j & 0xff;

        for (i = 0; i < CFS_HASH_ALG_MAX; i++)
                cfs_crypto_performance_test(i, data, data_len);

        kfree(data);
        return 0;
}

static int adler32;

int cfs_crypto_register(void)
{
        request_module("crc32c");

        adler32 = cfs_crypto_adler32_register();

        /* check all algorithms and do performance test */
        cfs_crypto_test_hashes();
        return 0;
}
void cfs_crypto_unregister(void)
{
        if (adler32 == 0)
                cfs_crypto_adler32_unregister();

        return;
}