1 | /* |
2 | * IP checksumming functions. |
3 | * (c) 2008 Gerd Hoffmann <kraxel@redhat.com> |
4 | * |
5 | * This program is free software; you can redistribute it and/or modify |
6 | * it under the terms of the GNU General Public License as published by |
7 | * the Free Software Foundation; under version 2 of the License. |
8 | * |
9 | * This program is distributed in the hope that it will be useful, |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
12 | * GNU General Public License for more details. |
13 | * |
14 | * You should have received a copy of the GNU General Public License |
15 | * along with this program; if not, see <http://www.gnu.org/licenses/>. |
16 | */ |
17 | |
18 | #ifndef QEMU_NET_CHECKSUM_H |
19 | #define QEMU_NET_CHECKSUM_H |
20 | |
21 | #include "qemu/bswap.h" |
22 | struct iovec; |
23 | |
24 | uint32_t net_checksum_add_cont(int len, uint8_t *buf, int seq); |
25 | uint16_t net_checksum_finish(uint32_t sum); |
26 | uint16_t net_checksum_tcpudp(uint16_t length, uint16_t proto, |
27 | uint8_t *addrs, uint8_t *buf); |
28 | void net_checksum_calculate(uint8_t *data, int length); |
29 | |
30 | static inline uint32_t |
31 | net_checksum_add(int len, uint8_t *buf) |
32 | { |
33 | return net_checksum_add_cont(len, buf, 0); |
34 | } |
35 | |
36 | static inline uint16_t |
37 | net_checksum_finish_nozero(uint32_t sum) |
38 | { |
39 | return net_checksum_finish(sum) ?: 0xFFFF; |
40 | } |
41 | |
42 | static inline uint16_t |
43 | net_raw_checksum(uint8_t *data, int length) |
44 | { |
45 | return net_checksum_finish(net_checksum_add(length, data)); |
46 | } |
47 | |
48 | /** |
49 | * net_checksum_add_iov: scatter-gather vector checksumming |
50 | * |
51 | * @iov: input scatter-gather array |
52 | * @iov_cnt: number of array elements |
53 | * @iov_off: starting iov offset for checksumming |
54 | * @size: length of data to be checksummed |
55 | * @csum_offset: offset of the checksum chunk |
56 | */ |
57 | uint32_t net_checksum_add_iov(const struct iovec *iov, |
58 | const unsigned int iov_cnt, |
59 | uint32_t iov_off, uint32_t size, |
60 | uint32_t csum_offset); |
61 | |
62 | typedef struct toeplitz_key_st { |
63 | uint32_t leftmost_32_bits; |
64 | uint8_t *next_byte; |
65 | } net_toeplitz_key; |
66 | |
67 | static inline |
68 | void net_toeplitz_key_init(net_toeplitz_key *key, uint8_t *key_bytes) |
69 | { |
70 | key->leftmost_32_bits = be32_to_cpu(*(uint32_t *)key_bytes); |
71 | key->next_byte = key_bytes + sizeof(uint32_t); |
72 | } |
73 | |
74 | static inline |
75 | void net_toeplitz_add(uint32_t *result, |
76 | uint8_t *input, |
77 | uint32_t len, |
78 | net_toeplitz_key *key) |
79 | { |
80 | register uint32_t accumulator = *result; |
81 | register uint32_t leftmost_32_bits = key->leftmost_32_bits; |
82 | register uint32_t byte; |
83 | |
84 | for (byte = 0; byte < len; byte++) { |
85 | register uint8_t input_byte = input[byte]; |
86 | register uint8_t key_byte = *(key->next_byte++); |
87 | register uint8_t bit; |
88 | |
89 | for (bit = 0; bit < 8; bit++) { |
90 | if (input_byte & (1 << 7)) { |
91 | accumulator ^= leftmost_32_bits; |
92 | } |
93 | |
94 | leftmost_32_bits = |
95 | (leftmost_32_bits << 1) | ((key_byte & (1 << 7)) >> 7); |
96 | |
97 | input_byte <<= 1; |
98 | key_byte <<= 1; |
99 | } |
100 | } |
101 | |
102 | key->leftmost_32_bits = leftmost_32_bits; |
103 | *result = accumulator; |
104 | } |
105 | |
106 | #endif /* QEMU_NET_CHECKSUM_H */ |
107 | |