net: move compute_mcast_idx() to net.h

Reduce duplicated codes.

Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Jason Wang 2012-03-05 11:08:50 +08:00 committed by Michael S. Tsirkin
parent afe0a59535
commit 7fc8d918b9
6 changed files with 26 additions and 98 deletions

23
net.c
View file

@ -1475,3 +1475,26 @@ int net_client_parse(QemuOptsList *opts_list, const char *optarg)
default_net = 0;
return 0;
}
/* From FreeBSD */
/* XXX: optimize */
unsigned compute_mcast_idx(const uint8_t *ep)
{
uint32_t crc;
int carry, i, j;
uint8_t b;
crc = 0xffffffff;
for (i = 0; i < 6; i++) {
b = *ep++;
for (j = 0; j < 8; j++) {
carry = ((crc & 0x80000000L) ? 1 : 0) ^ (b & 0x01);
crc <<= 1;
b >>= 1;
if (carry) {
crc = ((crc ^ POLYNOMIAL) | carry);
}
}
}
return crc >> 26;
}