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93 lines
2.0 KiB
93 lines
2.0 KiB
// 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 <[email protected]> |
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* 2002 Adam J. Richter <[email protected]> |
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* 2004 Jean-Luc Cooke <[email protected]> |
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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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static inline void memcpy_dir(void *buf, void *sgdata, size_t nbytes, int out) |
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{ |
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void *src = out ? buf : sgdata; |
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void *dst = out ? sgdata : buf; |
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memcpy(dst, src, nbytes); |
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} |
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void scatterwalk_copychunks(void *buf, struct scatter_walk *walk, |
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size_t nbytes, int out) |
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{ |
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for (;;) { |
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unsigned int len_this_page = scatterwalk_pagelen(walk); |
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u8 *vaddr; |
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if (len_this_page > nbytes) |
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len_this_page = nbytes; |
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if (out != 2) { |
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vaddr = scatterwalk_map(walk); |
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memcpy_dir(buf, vaddr, len_this_page, out); |
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scatterwalk_unmap(vaddr); |
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} |
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scatterwalk_advance(walk, len_this_page); |
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if (nbytes == len_this_page) |
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break; |
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buf += len_this_page; |
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nbytes -= len_this_page; |
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scatterwalk_pagedone(walk, out & 1, 1); |
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} |
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} |
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EXPORT_SYMBOL_GPL(scatterwalk_copychunks); |
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void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg, |
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unsigned int start, unsigned int nbytes, int out) |
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{ |
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struct scatter_walk walk; |
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struct scatterlist tmp[2]; |
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if (!nbytes) |
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return; |
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sg = scatterwalk_ffwd(tmp, sg, start); |
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scatterwalk_start(&walk, sg); |
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scatterwalk_copychunks(buf, &walk, nbytes, out); |
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scatterwalk_done(&walk, out, 0); |
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} |
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EXPORT_SYMBOL_GPL(scatterwalk_map_and_copy); |
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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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