blob: c16c94f88733e738f4ee1dff7a1334f9c2e39eb4
1 | /* |
2 | * Cryptographic API. |
3 | * |
4 | * Cipher operations. |
5 | * |
6 | * Copyright (c) 2002 James Morris <jmorris@intercode.com.au> |
7 | * 2002 Adam J. Richter <adam@yggdrasil.com> |
8 | * 2004 Jean-Luc Cooke <jlcooke@certainkey.com> |
9 | * |
10 | * This program is free software; you can redistribute it and/or modify it |
11 | * under the terms of the GNU General Public License as published by the Free |
12 | * Software Foundation; either version 2 of the License, or (at your option) |
13 | * any later version. |
14 | * |
15 | */ |
16 | |
17 | #include <crypto/scatterwalk.h> |
18 | #include <linux/kernel.h> |
19 | #include <linux/mm.h> |
20 | #include <linux/module.h> |
21 | #include <linux/scatterlist.h> |
22 | |
23 | static inline void memcpy_dir(void *buf, void *sgdata, size_t nbytes, int out) |
24 | { |
25 | void *src = out ? buf : sgdata; |
26 | void *dst = out ? sgdata : buf; |
27 | |
28 | memcpy(dst, src, nbytes); |
29 | } |
30 | |
31 | void scatterwalk_copychunks(void *buf, struct scatter_walk *walk, |
32 | size_t nbytes, int out) |
33 | { |
34 | for (;;) { |
35 | unsigned int len_this_page = scatterwalk_pagelen(walk); |
36 | u8 *vaddr; |
37 | |
38 | if (len_this_page > nbytes) |
39 | len_this_page = nbytes; |
40 | |
41 | if (out != 2) { |
42 | vaddr = scatterwalk_map(walk); |
43 | memcpy_dir(buf, vaddr, len_this_page, out); |
44 | scatterwalk_unmap(vaddr); |
45 | } |
46 | |
47 | scatterwalk_advance(walk, len_this_page); |
48 | |
49 | if (nbytes == len_this_page) |
50 | break; |
51 | |
52 | buf += len_this_page; |
53 | nbytes -= len_this_page; |
54 | |
55 | scatterwalk_pagedone(walk, out & 1, 1); |
56 | } |
57 | } |
58 | EXPORT_SYMBOL_GPL(scatterwalk_copychunks); |
59 | |
60 | void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg, |
61 | unsigned int start, unsigned int nbytes, int out) |
62 | { |
63 | struct scatter_walk walk; |
64 | struct scatterlist tmp[2]; |
65 | |
66 | if (!nbytes) |
67 | return; |
68 | |
69 | sg = scatterwalk_ffwd(tmp, sg, start); |
70 | |
71 | scatterwalk_start(&walk, sg); |
72 | scatterwalk_copychunks(buf, &walk, nbytes, out); |
73 | scatterwalk_done(&walk, out, 0); |
74 | } |
75 | EXPORT_SYMBOL_GPL(scatterwalk_map_and_copy); |
76 | |
77 | struct scatterlist *scatterwalk_ffwd(struct scatterlist dst[2], |
78 | struct scatterlist *src, |
79 | unsigned int len) |
80 | { |
81 | for (;;) { |
82 | if (!len) |
83 | return src; |
84 | |
85 | if (src->length > len) |
86 | break; |
87 | |
88 | len -= src->length; |
89 | src = sg_next(src); |
90 | } |
91 | |
92 | sg_init_table(dst, 2); |
93 | sg_set_page(dst, sg_page(src), src->length - len, src->offset + len); |
94 | scatterwalk_crypto_chain(dst, sg_next(src), 0, 2); |
95 | |
96 | return dst; |
97 | } |
98 | EXPORT_SYMBOL_GPL(scatterwalk_ffwd); |
99 |