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net: Introduce Toeplitz hash calculator

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Signed-off-by: Dmitry Fleytman <dmitry.fleytman@ravellosystems.com>
Signed-off-by: Leonid Bloch <leonid.bloch@ravellosystems.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
This commit is contained in:
Dmitry Fleytman 2016-06-01 11:23:36 +03:00 committed by Jason Wang
parent a4b387e623
commit 0478d1ddae
1 changed files with 45 additions and 0 deletions
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45
include/net/checksum.h
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@ -18,6 +18,7 @@
#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);
@ -50,4 +51,48 @@ uint32_t net_checksum_add_iov(const struct iovec *iov,
const unsigned int iov_cnt,
uint32_t iov_off, uint32_t size);
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 */