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authorDmitry Fleytman <dmitry.fleytman@ravellosystems.com>2016-06-01 11:23:36 +0300
committerJason Wang <jasowang@redhat.com>2016-06-02 10:42:27 +0800
commit0478d1ddaea3e6e1a19faa82f5bc2ef8f3300c42 (patch)
treefa33c7c81869e2f102b7e8c1c44c5348868e57e3 /include/net
parenta4b387e623f4e17bd4784cf76e3f8c15800365dc (diff)
net: Introduce Toeplitz hash calculator
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>
Diffstat (limited to 'include/net')
-rw-r--r--include/net/checksum.h45
1 files changed, 45 insertions, 0 deletions
diff --git a/include/net/checksum.h b/include/net/checksum.h
index 7de1acb79a..dd8b4f6dc2 100644
--- a/include/net/checksum.h
+++ b/include/net/checksum.h
@@ -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 */