/*
 * Cryptographic API for algorithms (i.e., low-level API).
 *
 * 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 <linux/byteorder.h>
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/printk.h>
#include <linux/rtnetlink.h>
#include <linux/slab.h>
#include <linux/string.h>

#include "internal.h"

static inline int crypto_set_driver_name(struct crypto_alg *alg)
{
	static const char suffix[] = "-generic";
	char *driver_name = alg->cra_driver_name;
	int len;

	if (*driver_name)
		return 0;

	len = strlcpy(driver_name, alg->cra_name, CRYPTO_MAX_ALG_NAME);
	if (len + sizeof(suffix) > CRYPTO_MAX_ALG_NAME)
		return -ENAMETOOLONG;

	memcpy(driver_name + len, suffix, sizeof(suffix));
	return 0;
}

static int crypto_check_alg(struct crypto_alg *alg)
{
	if (alg->cra_alignmask & (alg->cra_alignmask + 1))
		return -EINVAL;

	if (alg->cra_blocksize > PAGE_SIZE / 8)
		return -EINVAL;

	if (alg->cra_priority < 0)
		return -EINVAL;

	atomic_set(&alg->cra_refcnt, 1);

	return crypto_set_driver_name(alg);
}

static int __crypto_register_alg(struct crypto_alg *alg)
{
	struct crypto_alg *q;
	int ret = -EAGAIN;

	INIT_LIST_HEAD(&alg->cra_users);

	ret = -EEXIST;

	list_for_each_entry(q, &crypto_alg_list, cra_list) {
		if (q == alg)
			goto err;

		if (!strcmp(q->cra_driver_name, alg->cra_name) ||
		    !strcmp(q->cra_name, alg->cra_driver_name))
			goto err;
	}

	list_add(&alg->cra_list, &crypto_alg_list);
	return 0;
err:
	return ret;
}

void crypto_remove_final(struct list_head *list)
{
	struct crypto_alg *alg;
	struct crypto_alg *n;

	list_for_each_entry_safe(alg, n, list, cra_list) {
		list_del_init(&alg->cra_list);
		crypto_alg_put(alg);
	}
}

int crypto_register_alg(struct crypto_alg *alg)
{
	int err;

	err = crypto_check_alg(alg);
	if (err)
		return err;

	down_write(&crypto_alg_sem);
	err = __crypto_register_alg(alg);
	up_write(&crypto_alg_sem);

	return err;
}

static int crypto_remove_alg(struct crypto_alg *alg, struct list_head *list)
{
	if (unlikely(list_empty(&alg->cra_list)))
		return -ENOENT;

	list_del_init(&alg->cra_list);
	return 0;
}

int crypto_unregister_alg(struct crypto_alg *alg)
{
	int ret;
	LIST_HEAD(list);

	down_write(&crypto_alg_sem);
	ret = crypto_remove_alg(alg, &list);
	up_write(&crypto_alg_sem);

	if (ret)
		return ret;

	BUG_ON(atomic_read(&alg->cra_refcnt) != 1);
	if (alg->cra_destroy)
		alg->cra_destroy(alg);

	crypto_remove_final(&list);
	return 0;
}

int crypto_register_algs(struct crypto_alg *algs, int count)
{
	int i, ret;

	for (i = 0; i < count; i++) {
		ret = crypto_register_alg(&algs[i]);
		if (ret)
			goto err;
	}

	return 0;

err:
	for (--i; i >= 0; --i)
		crypto_unregister_alg(&algs[i]);

	return ret;
}

int crypto_unregister_algs(struct crypto_alg *algs, int count)
{
	int i, ret;

	for (i = 0; i < count; i++) {
		ret = crypto_unregister_alg(&algs[i]);
		if (ret)
			pr_err("Failed to unregister %s %s: %d\n",
			       algs[i].cra_driver_name, algs[i].cra_name, ret);
	}

	return 0;
}

struct crypto_attr_type *crypto_get_attr_type(struct rtattr **tb)
{
	struct rtattr *rta = tb[0];
	struct crypto_attr_type *algt;

	if (!rta)
		return ERR_PTR(-ENOENT);
	if (RTA_PAYLOAD(rta) < sizeof(*algt))
		return ERR_PTR(-EINVAL);
	if (rta->rta_type != CRYPTOA_TYPE)
		return ERR_PTR(-EINVAL);

	algt = RTA_DATA(rta);

	return algt;
}

int crypto_check_attr_type(struct rtattr **tb, u32 type)
{
	struct crypto_attr_type *algt;

	algt = crypto_get_attr_type(tb);
	if (IS_ERR(algt))
		return PTR_ERR(algt);

	if ((algt->type ^ type) & algt->mask)
		return -EINVAL;

	return 0;
}

const char *crypto_attr_alg_name(struct rtattr *rta)
{
	struct crypto_attr_alg *alga;

	if (!rta)
		return ERR_PTR(-ENOENT);
	if (RTA_PAYLOAD(rta) < sizeof(*alga))
		return ERR_PTR(-EINVAL);
	if (rta->rta_type != CRYPTOA_ALG)
		return ERR_PTR(-EINVAL);

	alga = RTA_DATA(rta);
	alga->name[CRYPTO_MAX_ALG_NAME - 1] = 0;

	return alga->name;
}

struct crypto_alg *crypto_attr_alg2(struct rtattr *rta,
				    const struct crypto_type *frontend,
				    u32 type, u32 mask)
{
	const char *name;

	name = crypto_attr_alg_name(rta);
	if (IS_ERR(name))
		return ERR_CAST(name);

	return crypto_find_alg(name, frontend, type, mask);
}

int crypto_attr_u32(struct rtattr *rta, u32 *num)
{
	struct crypto_attr_u32 *nu32;

	if (!rta)
		return -ENOENT;
	if (RTA_PAYLOAD(rta) < sizeof(*nu32))
		return -EINVAL;
	if (rta->rta_type != CRYPTOA_U32)
		return -EINVAL;

	nu32 = RTA_DATA(rta);
	*num = nu32->num;

	return 0;
}

static inline void crypto_inc_byte(u8 *a, unsigned int size)
{
	u8 *b = (a + size);
	u8 c;

	for (; size; size--) {
		c = *--b + 1;
		*b = c;
		if (c)
			break;
	}
}

void crypto_inc(u8 *a, unsigned int size)
{
	__be32 *b = (__be32 *)(a + size);
	u32 c;

	for (; size >= 4; size -= 4) {
		c = be32_to_cpu(*--b) + 1;
		*b = cpu_to_be32(c);
		if (c)
			return;
	}

	crypto_inc_byte(a, size);
}

static inline void crypto_xor_byte(u8 *a, const u8 *b, unsigned int size)
{
	for (; size; size--)
		*a++ ^= *b++;
}

void crypto_xor(u8 *dst, const u8 *src, unsigned int size)
{
	u32 *a = (u32 *)dst;
	u32 *b = (u32 *)src;

	for (; size >= 4; size -= 4)
		*a++ ^= *b++;

	crypto_xor_byte((u8 *)a, (u8 *)b, size);
}

unsigned int crypto_alg_extsize(struct crypto_alg *alg)
{
	return alg->cra_ctxsize +
	       (alg->cra_alignmask & ~(crypto_tfm_ctx_alignment() - 1));
}

int crypto_type_has_alg(const char *name, const struct crypto_type *frontend,
			u32 type, u32 mask)
{
	int ret = 0;
	struct crypto_alg *alg = crypto_find_alg(name, frontend, type, mask);

	if (!IS_ERR(alg)) {
		crypto_alg_put(alg);
		ret = 1;
	}

	return ret;
}

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Cryptographic algorithms API");