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/*
* Common values for the ChaCha20 algorithm
*/
#ifndef _CRYPTO_CHACHA20_H
#define _CRYPTO_CHACHA20_H
#include <linux/types.h>
#include <linux/crypto.h>
#include <linux/unaligned.h>
#define CHACHA_IV_SIZE 16
#define CHACHA_KEY_SIZE 32
#define CHACHA_BLOCK_SIZE 64
#define CHACHA_KEY_WORDS 8
#define CHACHA_STATE_WORDS 16
struct chacha_state {
u32 x[CHACHA_STATE_WORDS];
};
enum chacha_constants { /* expand 32-byte k */
CHACHA_CONSTANT_EXPA = 0x61707865U,
CHACHA_CONSTANT_ND_3 = 0x3320646eU,
CHACHA_CONSTANT_2_BY = 0x79622d32U,
CHACHA_CONSTANT_TE_K = 0x6b206574U
};
static inline void chacha_init_consts(struct chacha_state *state)
{
state->x[0] = CHACHA_CONSTANT_EXPA;
state->x[1] = CHACHA_CONSTANT_ND_3;
state->x[2] = CHACHA_CONSTANT_2_BY;
state->x[3] = CHACHA_CONSTANT_TE_K;
}
static inline void chacha_init(struct chacha_state *state,
const u32 key[CHACHA_KEY_WORDS],
const u8 iv[CHACHA_IV_SIZE])
{
chacha_init_consts(state);
state->x[4] = key[0];
state->x[5] = key[1];
state->x[6] = key[2];
state->x[7] = key[3];
state->x[8] = key[4];
state->x[9] = key[5];
state->x[10] = key[6];
state->x[11] = key[7];
state->x[12] = get_unaligned_le32(iv + 0);
state->x[13] = get_unaligned_le32(iv + 4);
state->x[14] = get_unaligned_le32(iv + 8);
state->x[15] = get_unaligned_le32(iv + 12);
}
#include <sodium/crypto_stream_chacha20.h>
static inline void chacha20_crypt(struct chacha_state *state, u8 *dst, const u8 *src,
unsigned int bytes)
{
u32 *key = state->x + 4;
u32 *iv = state->x + 12;
int ret = crypto_stream_chacha20_xor_ic(dst, src, bytes,
(void *) &iv[2],
iv[0] | ((u64) iv[1] << 32),
(void *) key);
BUG_ON(ret);
}
static inline void chacha_zeroize_state(struct chacha_state *state)
{
memzero_explicit(state, sizeof(*state));
}
#endif
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