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Checksum-related utility functions

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net_checksum_add_cont()
checksum calculation for scattered data with odd chunk sizes

net_raw_checksum()
checksum calculation for a buffer

Signed-off-by: Dmitry Fleytman <dmitry@daynix.com>
Signed-off-by: Yan Vugenfirer <yan@daynix.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Dmitry Fleytman 2013-03-09 11:21:02 +02:00 committed by Stefan Hajnoczi
parent 20048d0a12
commit 5acf5ea4bc
2 changed files with 20 additions and 7 deletions
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14
include/net/checksum.h
View File

@ -20,10 +20,22 @@
#include <stdint.h>
uint32_t net_checksum_add(int len, uint8_t *buf);
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_raw_checksum(uint8_t *data, int length)
{
return net_checksum_finish(net_checksum_add(length, data));
}
#endif /* QEMU_NET_CHECKSUM_H */

13
net/checksum.c
View File

@ -20,16 +20,17 @@
#define PROTO_TCP 6
#define PROTO_UDP 17
uint32_t net_checksum_add(int len, uint8_t *buf)
uint32_t net_checksum_add_cont(int len, uint8_t *buf, int seq)
{
uint32_t sum = 0;
int i;
for (i = 0; i < len; i++) {
if (i & 1)
sum += (uint32_t)buf[i];
else
sum += (uint32_t)buf[i] << 8;
for (i = seq; i < seq + len; i++) {
if (i & 1) {
sum += (uint32_t)buf[i - seq];
} else {
sum += (uint32_t)buf[i - seq] << 8;
}
}
return sum;
}