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/*
* IP checksumming functions.
* (c) 2008 Gerd Hoffmann <kraxel@redhat.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; under version 2 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#ifndef QEMU_NET_CHECKSUM_H
#define QEMU_NET_CHECKSUM_H
#include "qemu/bswap.h"
struct iovec;
uint32_t net_checksum_add_cont(int len, uint8_t *buf, int seq);
uint16_t net_checksum_finish(uint32_t sum);
uint16_t net_checksum_tcpudp(uint16_t length, uint16_t proto,
uint8_t *addrs, uint8_t *buf);
void net_checksum_calculate(uint8_t *data, int length);
static inline uint32_t
net_checksum_add(int len, uint8_t *buf)
{
return net_checksum_add_cont(len, buf, 0);
}
static inline uint16_t
net_checksum_finish_nozero(uint32_t sum)
{
return net_checksum_finish(sum) ?: 0xFFFF;
}
static inline uint16_t
net_raw_checksum(uint8_t *data, int length)
{
return net_checksum_finish(net_checksum_add(length, data));
}
/**
* net_checksum_add_iov: scatter-gather vector checksumming
*
* @iov: input scatter-gather array
* @iov_cnt: number of array elements
* @iov_off: starting iov offset for checksumming
* @size: length of data to be checksummed
* @csum_offset: offset of the checksum chunk
*/
uint32_t net_checksum_add_iov(const struct iovec *iov,
const unsigned int iov_cnt,
uint32_t iov_off, uint32_t size,
uint32_t csum_offset);
typedef struct toeplitz_key_st {
uint32_t leftmost_32_bits;
uint8_t *next_byte;
} net_toeplitz_key;
static inline
void net_toeplitz_key_init(net_toeplitz_key *key, uint8_t *key_bytes)
{
key->leftmost_32_bits = be32_to_cpu(*(uint32_t *)key_bytes);
key->next_byte = key_bytes + sizeof(uint32_t);
}
static inline
void net_toeplitz_add(uint32_t *result,
uint8_t *input,
uint32_t len,
net_toeplitz_key *key)
{
register uint32_t accumulator = *result;
register uint32_t leftmost_32_bits = key->leftmost_32_bits;
register uint32_t byte;
for (byte = 0; byte < len; byte++) {
register uint8_t input_byte = input[byte];
register uint8_t key_byte = *(key->next_byte++);
register uint8_t bit;
for (bit = 0; bit < 8; bit++) {
if (input_byte & (1 << 7)) {
accumulator ^= leftmost_32_bits;
}
leftmost_32_bits =
(leftmost_32_bits << 1) | ((key_byte & (1 << 7)) >> 7);
input_byte <<= 1;
key_byte <<= 1;
}
}
key->leftmost_32_bits = leftmost_32_bits;
*result = accumulator;
}
#endif /* QEMU_NET_CHECKSUM_H */
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