/* SPDX-License-Identifier: GPL-2.0 *//* * Common values and helper functions for the ChaCha and XChaCha stream ciphers. * * XChaCha extends ChaCha's nonce to 192 bits, while provably retaining ChaCha's * security.  Here they share the same key size, tfm context, and setkey * function; only their IV size and encrypt/decrypt function differ. * * The ChaCha paper specifies 20, 12, and 8-round variants.  In general, it is * recommended to use the 20-round variant ChaCha20.  However, the other * variants can be needed in some performance-sensitive scenarios.  The generic * ChaCha code currently allows only the 20 and 12-round variants. */ #ifndef _CRYPTO_CHACHA_H#define _CRYPTO_CHACHA_H #include <asm/unaligned.h>#include <linux/types.h> /* 32-bit stream position, then 96-bit nonce (RFC7539 convention) */#define CHACHA_IV_SIZE		16 #define CHACHA_KEY_SIZE		32#define CHACHA_BLOCK_SIZE	64#define CHACHAPOLY_IV_SIZE	12 #define CHACHA_STATE_WORDS	(CHACHA_BLOCK_SIZE / sizeof(u32)) /* 192-bit nonce, then 64-bit stream position */#define XCHACHA_IV_SIZE		32 void chacha_block_generic(u32 *state, u8 *stream, int nrounds);static inline void chacha20_block(u32 *state, u8 *stream){	chacha_block_generic(state, stream, 20);} void hchacha_block_arch(const u32 *state, u32 *out, int nrounds);void hchacha_block_generic(const u32 *state, u32 *out, int nrounds); static inline void hchacha_block(const u32 *state, u32 *out, int nrounds){	if (IS_ENABLED(CONFIG_CRYPTO_ARCH_HAVE_LIB_CHACHA))		hchacha_block_arch(state, out, nrounds);	else		hchacha_block_generic(state, out, nrounds);} void chacha_init_arch(u32 *state, const u32 *key, const u8 *iv);static inline void chacha_init_generic(u32 *state, const u32 *key, const u8 *iv){	state[0]  = 0x61707865; /* "expa" */	state[1]  = 0x3320646e; /* "nd 3" */	state[2]  = 0x79622d32; /* "2-by" */	state[3]  = 0x6b206574; /* "te k" */	state[4]  = key[0];	state[5]  = key[1];	state[6]  = key[2];	state[7]  = key[3];	state[8]  = key[4];	state[9]  = key[5];	state[10] = key[6];	state[11] = key[7];	state[12] = get_unaligned_le32(iv +  0);	state[13] = get_unaligned_le32(iv +  4);	state[14] = get_unaligned_le32(iv +  8);	state[15] = get_unaligned_le32(iv + 12);} static inline void chacha_init(u32 *state, const u32 *key, const u8 *iv){	if (IS_ENABLED(CONFIG_CRYPTO_ARCH_HAVE_LIB_CHACHA))		chacha_init_arch(state, key, iv);	else		chacha_init_generic(state, key, iv);} void chacha_crypt_arch(u32 *state, u8 *dst, const u8 *src,		       unsigned int bytes, int nrounds);void chacha_crypt_generic(u32 *state, u8 *dst, const u8 *src,			  unsigned int bytes, int nrounds); static inline void chacha_crypt(u32 *state, u8 *dst, const u8 *src,				unsigned int bytes, int nrounds){	if (IS_ENABLED(CONFIG_CRYPTO_ARCH_HAVE_LIB_CHACHA))		chacha_crypt_arch(state, dst, src, bytes, nrounds);	else		chacha_crypt_generic(state, dst, src, bytes, nrounds);} static inline void chacha20_crypt(u32 *state, u8 *dst, const u8 *src,				  unsigned int bytes){	chacha_crypt(state, dst, src, bytes, 20);} #endif /* _CRYPTO_CHACHA_H */