1. 根目录:
2. include
3. crypto
4. md5.h

#ifndef _CRYPTO_MD5_H
#define _CRYPTO_MD5_H

#include <linux/types.h>

#define MD5_DIGEST_SIZE		16
#define MD5_HMAC_BLOCK_SIZE	64
#define MD5_BLOCK_WORDS		16
#define MD5_HASH_WORDS		4

struct md5_state {
	u32 hash[MD5_HASH_WORDS];
	u32 block[MD5_BLOCK_WORDS];
	u64 byte_count;
};

#endif