blockhash.h

 1/* SPDX-License-Identifier: GPL-2.0-or-later */
 2/*
 3 * Handle partial blocks for block hash.
 4 *
 5 * Copyright (c) 2015 Linaro Ltd <ard.biesheuvel@linaro.org>
 6 * Copyright (c) 2025 Herbert Xu <herbert@gondor.apana.org.au>
 7 */
 8
 9#ifndef _CRYPTO_INTERNAL_BLOCKHASH_H
10#define _CRYPTO_INTERNAL_BLOCKHASH_H
11
12#include <linux/string.h>
13#include <linux/types.h>
14
15#define BLOCK_HASH_UPDATE_BASE(block_fn, state, src, nbytes, bs, dv,	\
16			       buf, buflen)				\
17	({								\
18		typeof(block_fn) *_block_fn = &(block_fn);		\
19		typeof(state + 0) _state = (state);			\
20		unsigned int _buflen = (buflen);			\
21		size_t _nbytes = (nbytes);				\
22		unsigned int _bs = (bs);				\
23		const u8 *_src = (src);					\
24		u8 *_buf = (buf);					\
25		while ((_buflen + _nbytes) >= _bs) {			\
26			const u8 *data = _src;				\
27			size_t len = _nbytes;				\
28			size_t blocks;					\
29			int remain;					\
30			if (_buflen) {					\
31				remain = _bs - _buflen;			\
32				memcpy(_buf + _buflen, _src, remain);	\
33				data = _buf;				\
34				len = _bs;				\
35			}						\
36			remain = len % bs;				\
37			blocks = (len - remain) / (dv);			\
38			(*_block_fn)(_state, data, blocks);		\
39			_src += len - remain - _buflen;			\
40			_nbytes -= len - remain - _buflen;		\
41			_buflen = 0;					\
42		}							\
43		memcpy(_buf + _buflen, _src, _nbytes);			\
44		_buflen += _nbytes;					\
45	})
46
47#define BLOCK_HASH_UPDATE(block, state, src, nbytes, bs, buf, buflen) \
48	BLOCK_HASH_UPDATE_BASE(block, state, src, nbytes, bs, 1, buf, buflen)
49#define BLOCK_HASH_UPDATE_BLOCKS(block, state, src, nbytes, bs, buf, buflen) \
50	BLOCK_HASH_UPDATE_BASE(block, state, src, nbytes, bs, bs, buf, buflen)
51
52#endif	/* _CRYPTO_INTERNAL_BLOCKHASH_H */