/* SPDX-License-Identifier: GPL-2.0-or-later *//* * CTR: Counter mode * * Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au> */ #ifndef _CRYPTO_CTR_H#define _CRYPTO_CTR_H #include <crypto/algapi.h>#include <crypto/internal/skcipher.h>#include <linux/string.h>#include <linux/types.h> #define CTR_RFC3686_NONCE_SIZE 4#define CTR_RFC3686_IV_SIZE 8#define CTR_RFC3686_BLOCK_SIZE 16 static inline int crypto_ctr_encrypt_walk(struct skcipher_request *req,					  void (*fn)(struct crypto_skcipher *,						     const u8 *, u8 *)){	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);	int blocksize = crypto_skcipher_chunksize(tfm);	u8 buf[MAX_CIPHER_BLOCKSIZE];	struct skcipher_walk walk;	int err; 	/* avoid integer division due to variable blocksize parameter */	if (WARN_ON_ONCE(!is_power_of_2(blocksize)))		return -EINVAL; 	err = skcipher_walk_virt(&walk, req, false); 	while (walk.nbytes > 0) {		const u8 *src = walk.src.virt.addr;		u8 *dst = walk.dst.virt.addr;		int nbytes = walk.nbytes;		int tail = 0; 		if (nbytes < walk.total) {			tail = walk.nbytes & (blocksize - 1);			nbytes -= tail;		} 		do {			int bsize = min(nbytes, blocksize); 			fn(tfm, walk.iv, buf); 			crypto_xor_cpy(dst, src, buf, bsize);			crypto_inc(walk.iv, blocksize); 			dst += bsize;			src += bsize;			nbytes -= bsize;		} while (nbytes > 0); 		err = skcipher_walk_done(&walk, tail);	}	return err;} #endif  /* _CRYPTO_CTR_H */