/*
 * CBC: Cipher Block Chaining mode
 *
 * Copyright (c) 2016 Herbert Xu <herbert@gondor.apana.org.au>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 *
 */

#ifndef _CRYPTO_CBC_H
#define _CRYPTO_CBC_H

#include <crypto/internal/skcipher.h>
#include <linux/string.h>
#include <linux/types.h>

static inline int crypto_cbc_encrypt_segment(
	struct skcipher_walk *walk, struct crypto_skcipher *tfm,
	void (*fn)(struct crypto_skcipher *, const u8 *, u8 *))
{
	unsigned int bsize = crypto_skcipher_blocksize(tfm);
	unsigned int nbytes = walk->nbytes;
	u8 *src = walk->src.virt.addr;
	u8 *dst = walk->dst.virt.addr;
	u8 *iv = walk->iv;

	do {
		crypto_xor(iv, src, bsize);
		fn(tfm, iv, dst);
		memcpy(iv, dst, bsize);

		src += bsize;
		dst += bsize;
	} while ((nbytes -= bsize) >= bsize);

	return nbytes;
}

static inline int crypto_cbc_encrypt_inplace(
	struct skcipher_walk *walk, struct crypto_skcipher *tfm,
	void (*fn)(struct crypto_skcipher *, const u8 *, u8 *))
{
	unsigned int bsize = crypto_skcipher_blocksize(tfm);
	unsigned int nbytes = walk->nbytes;
	u8 *src = walk->src.virt.addr;
	u8 *iv = walk->iv;

	do {
		crypto_xor(src, iv, bsize);
		fn(tfm, src, src);
		iv = src;

		src += bsize;
	} while ((nbytes -= bsize) >= bsize);

	memcpy(walk->iv, iv, bsize);

	return nbytes;
}

static inline int crypto_cbc_encrypt_walk(struct skcipher_request *req,
					  void (*fn)(struct crypto_skcipher *,
						     const u8 *, u8 *))
{
	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
	struct skcipher_walk walk;
	int err;

	err = skcipher_walk_virt(&walk, req, false);

	while (walk.nbytes) {
		if (walk.src.virt.addr == walk.dst.virt.addr)
			err = crypto_cbc_encrypt_inplace(&walk, tfm, fn);
		else
			err = crypto_cbc_encrypt_segment(&walk, tfm, fn);
		err = skcipher_walk_done(&walk, err);
	}

	return err;
}

static inline int crypto_cbc_decrypt_segment(
	struct skcipher_walk *walk, struct crypto_skcipher *tfm,
	void (*fn)(struct crypto_skcipher *, const u8 *, u8 *))
{
	unsigned int bsize = crypto_skcipher_blocksize(tfm);
	unsigned int nbytes = walk->nbytes;
	u8 *src = walk->src.virt.addr;
	u8 *dst = walk->dst.virt.addr;
	u8 *iv = walk->iv;

	do {
		fn(tfm, src, dst);
		crypto_xor(dst, iv, bsize);
		iv = src;

		src += bsize;
		dst += bsize;
	} while ((nbytes -= bsize) >= bsize);

	memcpy(walk->iv, iv, bsize);

	return nbytes;
}

static inline int crypto_cbc_decrypt_inplace(
	struct skcipher_walk *walk, struct crypto_skcipher *tfm,
	void (*fn)(struct crypto_skcipher *, const u8 *, u8 *))
{
	unsigned int bsize = crypto_skcipher_blocksize(tfm);
	unsigned int nbytes = walk->nbytes;
	u8 *src = walk->src.virt.addr;
	u8 last_iv[bsize];

	/* Start of the last block. */
	src += nbytes - (nbytes & (bsize - 1)) - bsize;
	memcpy(last_iv, src, bsize);

	for (;;) {
		fn(tfm, src, src);
		if ((nbytes -= bsize) < bsize)
			break;
		crypto_xor(src, src - bsize, bsize);
		src -= bsize;
	}

	crypto_xor(src, walk->iv, bsize);
	memcpy(walk->iv, last_iv, bsize);

	return nbytes;
}

static inline int crypto_cbc_decrypt_blocks(
	struct skcipher_walk *walk, struct crypto_skcipher *tfm,
	void (*fn)(struct crypto_skcipher *, const u8 *, u8 *))
{
	if (walk->src.virt.addr == walk->dst.virt.addr)
		return crypto_cbc_decrypt_inplace(walk, tfm, fn);
	else
		return crypto_cbc_decrypt_segment(walk, tfm, fn);
}

#endif	/* _CRYPTO_CBC_H */
r>
<tr><td><span title='2017-02-09 22:59:34 -0500'>2017-02-09</span></td><td><a href='/cgit.cgi/linux/net-next.git/commit/net/openvswitch?h=nds-private-remove&amp;id=316d4d78cf9b6795b83f97c45368748741df418c'>openvswitch: Pack struct sw_flow_key.</a></td><td>Jarno Rajahalme</td><td>4</td><td><span class='deletions'>-34</span>/<span class='insertions'>+39</span></td></tr>
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<tr><td><span title='2017-02-09 22:59:34 -0500'>2017-02-09</span></td><td><a href='/cgit.cgi/linux/net-next.git/commit/net/openvswitch?h=nds-private-remove&amp;id=09aa98ad496d6b11a698b258bc64d7f64c55d682'>openvswitch: Inherit master's labels.</a></td><td>Jarno Rajahalme</td><td>1</td><td><span class='deletions'>-14</span>/<span class='insertions'>+31</span></td></tr>
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<tr><td><span title='2017-02-09 22:59:34 -0500'>2017-02-09</span></td><td><a href='/cgit.cgi/linux/net-next.git/commit/net/openvswitch?h=nds-private-remove&amp;id=b87cec3814ccc7f6afb0a1378ee7e5110d07cdd3'>openvswitch: Simplify labels length logic.</a></td><td>Jarno Rajahalme</td><td>1</td><td><span class='deletions'>-11</span>/<span class='insertions'>+9</span></td></tr>
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<tr><td><span title='2017-02-09 22:59:34 -0500'>2017-02-09</span></td><td><a href='/cgit.cgi/linux/net-next.git/commit/net/openvswitch?h=nds-private-remove&amp;id=9ff464db50e437eef131f719cc2e9902eea9c607'>openvswitch: Use inverted tuple in ovs_ct_find_existing() if NATted.</a></td><td>Jarno Rajahalme</td><td>1</td><td><span class='deletions'>-2</span>/<span class='insertions'>+22</span></td></tr>
<tr><td><span title='2017-02-09 22:59:34 -0500'>2017-02-09</span></td><td><a href='/cgit.cgi/linux/net-next.git/commit/net/openvswitch?h=nds-private-remove&amp;id=5e17da634a21b1200853fe82ba67d6571f2beabe'>openvswitch: Fix comments for skb-&gt;_nfct</a></td><td>Jarno Rajahalme</td><td>1</td><td><span class='deletions'>-7</span>/<span class='insertions'>+7</span></td></tr>
<tr><td><span title='2017-02-03 16:58:20 -0500'>2017-02-03</span></td><td><a href='/cgit.cgi/linux/net-next.git/commit/net/openvswitch?h=nds-private-remove&amp;id=52e01b84a244473074fc0612c169e2e043d58b01'>Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf-next</a></td><td>David S. Miller</td><td>1</td><td><span class='deletions'>-7</span>/<span class='insertions'>+5</span></td></tr>
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<tr><td><span title='2017-02-02 14:31:53 +0100'>2017-02-02</span></td><td><a href='/cgit.cgi/linux/net-next.git/commit/net/openvswitch?h=nds-private-remove&amp;id=cb9c68363efb6d1f950ec55fb06e031ee70db5fc'>skbuff: add and use skb_nfct helper</a></td><td>Florian Westphal</td><td>1</td><td><span class='deletions'>-3</span>/<span class='insertions'>+3</span></td></tr>