113 lines
2.6 KiB
C
113 lines
2.6 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Cryptographic API.
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*
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* Cipher operations.
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*
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* Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
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* 2002 Adam J. Richter <adam@yggdrasil.com>
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* 2004 Jean-Luc Cooke <jlcooke@certainkey.com>
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*/
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#include <crypto/scatterwalk.h>
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/module.h>
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#include <linux/scatterlist.h>
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void scatterwalk_skip(struct scatter_walk *walk, unsigned int nbytes)
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{
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struct scatterlist *sg = walk->sg;
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nbytes += walk->offset - sg->offset;
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while (nbytes > sg->length) {
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nbytes -= sg->length;
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sg = sg_next(sg);
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}
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walk->sg = sg;
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walk->offset = sg->offset + nbytes;
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}
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EXPORT_SYMBOL_GPL(scatterwalk_skip);
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inline void memcpy_from_scatterwalk(void *buf, struct scatter_walk *walk,
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unsigned int nbytes)
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{
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do {
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const void *src_addr;
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unsigned int to_copy;
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src_addr = scatterwalk_next(walk, nbytes, &to_copy);
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memcpy(buf, src_addr, to_copy);
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scatterwalk_done_src(walk, src_addr, to_copy);
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buf += to_copy;
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nbytes -= to_copy;
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} while (nbytes);
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}
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EXPORT_SYMBOL_GPL(memcpy_from_scatterwalk);
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inline void memcpy_to_scatterwalk(struct scatter_walk *walk, const void *buf,
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unsigned int nbytes)
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{
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do {
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void *dst_addr;
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unsigned int to_copy;
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dst_addr = scatterwalk_next(walk, nbytes, &to_copy);
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memcpy(dst_addr, buf, to_copy);
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scatterwalk_done_dst(walk, dst_addr, to_copy);
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buf += to_copy;
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nbytes -= to_copy;
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} while (nbytes);
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}
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EXPORT_SYMBOL_GPL(memcpy_to_scatterwalk);
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void memcpy_from_sglist(void *buf, struct scatterlist *sg,
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unsigned int start, unsigned int nbytes)
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{
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struct scatter_walk walk;
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if (unlikely(nbytes == 0)) /* in case sg == NULL */
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return;
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scatterwalk_start_at_pos(&walk, sg, start);
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memcpy_from_scatterwalk(buf, &walk, nbytes);
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}
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EXPORT_SYMBOL_GPL(memcpy_from_sglist);
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void memcpy_to_sglist(struct scatterlist *sg, unsigned int start,
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const void *buf, unsigned int nbytes)
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{
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struct scatter_walk walk;
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if (unlikely(nbytes == 0)) /* in case sg == NULL */
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return;
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scatterwalk_start_at_pos(&walk, sg, start);
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memcpy_to_scatterwalk(&walk, buf, nbytes);
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}
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EXPORT_SYMBOL_GPL(memcpy_to_sglist);
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struct scatterlist *scatterwalk_ffwd(struct scatterlist dst[2],
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struct scatterlist *src,
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unsigned int len)
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{
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for (;;) {
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if (!len)
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return src;
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if (src->length > len)
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break;
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len -= src->length;
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src = sg_next(src);
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}
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sg_init_table(dst, 2);
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sg_set_page(dst, sg_page(src), src->length - len, src->offset + len);
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scatterwalk_crypto_chain(dst, sg_next(src), 2);
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return dst;
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}
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EXPORT_SYMBOL_GPL(scatterwalk_ffwd);
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