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1da177e4 LT |
1 | /* |
2 | * iovec manipulation routines. | |
3 | * | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or | |
6 | * modify it under the terms of the GNU General Public License | |
7 | * as published by the Free Software Foundation; either version | |
8 | * 2 of the License, or (at your option) any later version. | |
9 | * | |
10 | * Fixes: | |
11 | * Andrew Lunn : Errors in iovec copying. | |
12 | * Pedro Roque : Added memcpy_fromiovecend and | |
13 | * csum_..._fromiovecend. | |
14 | * Andi Kleen : fixed error handling for 2.1 | |
15 | * Alexey Kuznetsov: 2.1 optimisations | |
16 | * Andi Kleen : Fix csum*fromiovecend for IPv6. | |
17 | */ | |
18 | ||
19 | #include <linux/errno.h> | |
20 | #include <linux/module.h> | |
1da177e4 LT |
21 | #include <linux/kernel.h> |
22 | #include <linux/mm.h> | |
1da177e4 LT |
23 | #include <linux/net.h> |
24 | #include <linux/in6.h> | |
25 | #include <asm/uaccess.h> | |
26 | #include <asm/byteorder.h> | |
27 | #include <net/checksum.h> | |
28 | #include <net/sock.h> | |
29 | ||
1da177e4 LT |
30 | /* |
31 | * And now for the all-in-one: copy and checksum from a user iovec | |
32 | * directly to a datagram | |
33 | * Calls to csum_partial but the last must be in 32 bit chunks | |
34 | * | |
35 | * ip_build_xmit must ensure that when fragmenting only the last | |
36 | * call to this function will be unaligned also. | |
37 | */ | |
38 | int csum_partial_copy_fromiovecend(unsigned char *kdata, struct iovec *iov, | |
44bb9363 | 39 | int offset, unsigned int len, __wsum *csump) |
1da177e4 | 40 | { |
44bb9363 | 41 | __wsum csum = *csump; |
1da177e4 LT |
42 | int partial_cnt = 0, err = 0; |
43 | ||
44 | /* Skip over the finished iovecs */ | |
45 | while (offset >= iov->iov_len) { | |
46 | offset -= iov->iov_len; | |
47 | iov++; | |
48 | } | |
49 | ||
50 | while (len > 0) { | |
51 | u8 __user *base = iov->iov_base + offset; | |
52 | int copy = min_t(unsigned int, len, iov->iov_len - offset); | |
53 | ||
54 | offset = 0; | |
55 | ||
56 | /* There is a remnant from previous iov. */ | |
57 | if (partial_cnt) { | |
58 | int par_len = 4 - partial_cnt; | |
59 | ||
60 | /* iov component is too short ... */ | |
61 | if (par_len > copy) { | |
62 | if (copy_from_user(kdata, base, copy)) | |
63 | goto out_fault; | |
64 | kdata += copy; | |
65 | base += copy; | |
66 | partial_cnt += copy; | |
67 | len -= copy; | |
68 | iov++; | |
69 | if (len) | |
70 | continue; | |
71 | *csump = csum_partial(kdata - partial_cnt, | |
72 | partial_cnt, csum); | |
73 | goto out; | |
74 | } | |
75 | if (copy_from_user(kdata, base, par_len)) | |
76 | goto out_fault; | |
77 | csum = csum_partial(kdata - partial_cnt, 4, csum); | |
78 | kdata += par_len; | |
79 | base += par_len; | |
80 | copy -= par_len; | |
81 | len -= par_len; | |
82 | partial_cnt = 0; | |
83 | } | |
84 | ||
85 | if (len > copy) { | |
86 | partial_cnt = copy % 4; | |
87 | if (partial_cnt) { | |
88 | copy -= partial_cnt; | |
89 | if (copy_from_user(kdata + copy, base + copy, | |
4ec93edb | 90 | partial_cnt)) |
1da177e4 LT |
91 | goto out_fault; |
92 | } | |
93 | } | |
94 | ||
95 | if (copy) { | |
96 | csum = csum_and_copy_from_user(base, kdata, copy, | |
97 | csum, &err); | |
98 | if (err) | |
99 | goto out; | |
100 | } | |
101 | len -= copy + partial_cnt; | |
102 | kdata += copy + partial_cnt; | |
103 | iov++; | |
104 | } | |
4ec93edb | 105 | *csump = csum; |
1da177e4 LT |
106 | out: |
107 | return err; | |
108 | ||
109 | out_fault: | |
110 | err = -EFAULT; | |
111 | goto out; | |
112 | } | |
1da177e4 | 113 | EXPORT_SYMBOL(csum_partial_copy_fromiovecend); |
b4bf0777 JW |
114 | |
115 | unsigned long iov_pages(const struct iovec *iov, int offset, | |
116 | unsigned long nr_segs) | |
117 | { | |
118 | unsigned long seg, base; | |
119 | int pages = 0, len, size; | |
120 | ||
121 | while (nr_segs && (offset >= iov->iov_len)) { | |
122 | offset -= iov->iov_len; | |
123 | ++iov; | |
124 | --nr_segs; | |
125 | } | |
126 | ||
127 | for (seg = 0; seg < nr_segs; seg++) { | |
128 | base = (unsigned long)iov[seg].iov_base + offset; | |
129 | len = iov[seg].iov_len - offset; | |
130 | size = ((base & ~PAGE_MASK) + len + ~PAGE_MASK) >> PAGE_SHIFT; | |
131 | pages += size; | |
132 | offset = 0; | |
133 | } | |
134 | ||
135 | return pages; | |
136 | } | |
137 | EXPORT_SYMBOL(iov_pages); |