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     %€ГЛ„П<ПКїН ?ч     %/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
 * AEAD: Authenticated Encryption with Associated Data
 * 
 * Copyright (c) 2007-2015 Herbert Xu <herbert@gondor.apana.org.au>
 */

#ifndef _CRYPTO_AEAD_H
#define _CRYPTO_AEAD_H

#include <linux/container_of.h>
#include <linux/crypto.h>
#include <linux/slab.h>
#include <linux/types.h>

/**
 * DOC: Authenticated Encryption With Associated Data (AEAD) Cipher API
 *
 * The AEAD cipher API is used with the ciphers of type CRYPTO_ALG_TYPE_AEAD
 * (listed as type "aead" in /proc/crypto)
 *
 * The most prominent examples for this type of encryption is GCM and CCM.
 * However, the kernel supports other types of AEAD ciphers which are defined
 * with the following cipher string:
 *
 *	authenc(keyed message digest, block cipher)
 *
 * For example: authenc(hmac(sha256), cbc(aes))
 *
 * The example code provided for the symmetric key cipher operation
 * applies here as well. Naturally all *skcipher* symbols must be exchanged
 * the *aead* pendants discussed in the following. In addition, for the AEAD
 * operation, the aead_request_set_ad function must be used to set the
 * pointer to the associated data memory location before performing the
 * encryption or decryption operation. In case of an encryption, the associated
 * data memory is filled during the encryption operation. For decryption, the
 * associated data memory must contain data that is used to verify the integrity
 * of the decrypted data. Another deviation from the asynchronous block cipher
 * operation is that the caller should explicitly check for -EBADMSG of the
 * crypto_aead_decrypt. That error indicates an authentication error, i.e.
 * a breach in the integrity of the message. In essence, that -EBADMSG error
 * code is the key bonus an AEAD cipher has over "standard" block chaining
 * modes.
 *
 * Memory Structure:
 *
 * The source scatterlist must contain the concatenation of
 * associated data || plaintext or ciphertext.
 *
 * The destination scatterlist has the same layout, except that the plaintext
 * (resp. ciphertext) will grow (resp. shrink) by the authentication tag size
 * during encryption (resp. decryption).
 *
 * In-place encryption/decryption is enabled by using the same scatterlist
 * pointer for both the source and destination.
 *
 * Even in the out-of-place case, space must be reserved in the destination for
 * the associated data, even though it won't be written to.  This makes the
 * in-place and out-of-place cases more consistent.  It is permissible for the
 * "destination" associated data to alias the "source" associated data.
 *
 * As with the other scatterlist crypto APIs, zero-length scatterlist elements
 * are not allowed in the used part of the scatterlist.  Thus, if there is no
 * associated data, the first element must point to the plaintext/ciphertext.
 *
 * To meet the needs of IPsec, a special quirk applies to rfc4106, rfc4309,
 * rfc4543, and rfc7539esp ciphers.  For these ciphers, the final 'ivsize' bytes
 * of the associated data buffer must contain a second copy of the IV.  This is
 * in addition to the copy passed to aead_request_set_crypt().  These two IV
 * copies must not differ; different implementations of the same algorithm may
 * behave differently in that case.  Note that the algorithm might not actually
 * treat the IV as associated data; nevertheless the length passed to
 * aead_request_set_ad() must include it.
 */

struct crypto_aead;
struct scatterlist;

/**
 *	struct aead_request - AEAD request
 *	@base: Common attributes for async crypto requests
 *	@assoclen: Length in bytes of associated data for authentication
 *	@cryptlen: Length of data to be encrypted or decrypted
 *	@iv: Initialisation vector
 *	@src: Source data
 *	@dst: Destination data
 *	@__ctx: Start of private context data
 */
struct aead_request {
	struct crypto_async_request base;

	unsigned int assoclen;
	unsigned int cryptlen;

	u8 *iv;

	struct scatterlist *src;
	struct scatterlist *dst;

	void *__ctx[] CRYPTO_MINALIGN_ATTR;
};

/**
 * struct aead_alg - AEAD cip