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1/* SPDX-License-Identifier: GPL-2.0-or-later */2/*3 * CTR: Counter mode4 *5 * Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au>6 */7 8#ifndef _CRYPTO_CTR_H9#define _CRYPTO_CTR_H10 11#include <crypto/algapi.h>12#include <crypto/internal/skcipher.h>13#include <linux/string.h>14#include <linux/types.h>15 16#define CTR_RFC3686_NONCE_SIZE 417#define CTR_RFC3686_IV_SIZE 818#define CTR_RFC3686_BLOCK_SIZE 1619 20static inline int crypto_ctr_encrypt_walk(struct skcipher_request *req,21 void (*fn)(struct crypto_skcipher *,22 const u8 *, u8 *))23{24 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);25 int blocksize = crypto_skcipher_chunksize(tfm);26 u8 buf[MAX_CIPHER_BLOCKSIZE];27 struct skcipher_walk walk;28 int err;29 30 /* avoid integer division due to variable blocksize parameter */31 if (WARN_ON_ONCE(!is_power_of_2(blocksize)))32 return -EINVAL;33 34 err = skcipher_walk_virt(&walk, req, false);35 36 while (walk.nbytes > 0) {37 u8 *dst = walk.dst.virt.addr;38 u8 *src = walk.src.virt.addr;39 int nbytes = walk.nbytes;40 int tail = 0;41 42 if (nbytes < walk.total) {43 tail = walk.nbytes & (blocksize - 1);44 nbytes -= tail;45 }46 47 do {48 int bsize = min(nbytes, blocksize);49 50 fn(tfm, walk.iv, buf);51 52 crypto_xor_cpy(dst, src, buf, bsize);53 crypto_inc(walk.iv, blocksize);54 55 dst += bsize;56 src += bsize;57 nbytes -= bsize;58 } while (nbytes > 0);59 60 err = skcipher_walk_done(&walk, tail);61 }62 return err;63}64 65#endif /* _CRYPTO_CTR_H */66