aboutsummaryrefslogtreecommitdiff
path: root/net/net.c
diff options
context:
space:
mode:
authorMark Cave-Ayland <mark.cave-ayland@ilande.co.uk>2017-12-15 18:41:43 +0000
committerJason Wang <jasowang@redhat.com>2017-12-22 09:55:03 +0800
commiteaba8f34f0dac5e9296df9c2046d9601264c46a4 (patch)
tree47497a0be3a2e626b1dcc62eb36d0cc64f36e898 /net/net.c
parentd62644b46a86bce2c069af7122501e3ffd349d3c (diff)
net: move CRC32 calculation from compute_mcast_idx() into its own net_crc32() function
Separate out the standard ethernet CRC32 calculation into a new net_crc32() function, renaming the constant POLYNOMIAL to POLYNOMIAL_BE to make it clear that this is a big-endian CRC32 calculation. As part of the constant rename, remove the duplicate definition of POLYNOMIAL from eepro100.c and use the new POLYNOMIAL_BE constant instead. Once this is complete remove the existing CRC32 implementation from compute_mcast_idx() and call the new net_crc32() function in its place. Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Signed-off-by: Jason Wang <jasowang@redhat.com>
Diffstat (limited to 'net/net.c')
-rw-r--r--net/net.c16
1 files changed, 11 insertions, 5 deletions
diff --git a/net/net.c b/net/net.c
index 39ef546708..a14dc9910c 100644
--- a/net/net.c
+++ b/net/net.c
@@ -1581,25 +1581,31 @@ int net_client_parse(QemuOptsList *opts_list, const char *optarg)
/* From FreeBSD */
/* XXX: optimize */
-unsigned compute_mcast_idx(const uint8_t *ep)
+uint32_t net_crc32(const uint8_t *p, int len)
{
uint32_t crc;
int carry, i, j;
uint8_t b;
crc = 0xffffffff;
- for (i = 0; i < 6; i++) {
- b = *ep++;
+ for (i = 0; i < len; i++) {
+ b = *p++;
for (j = 0; j < 8; j++) {
carry = ((crc & 0x80000000L) ? 1 : 0) ^ (b & 0x01);
crc <<= 1;
b >>= 1;
if (carry) {
- crc = ((crc ^ POLYNOMIAL) | carry);
+ crc = ((crc ^ POLYNOMIAL_BE) | carry);
}
}
}
- return crc >> 26;
+
+ return crc;
+}
+
+unsigned compute_mcast_idx(const uint8_t *ep)
+{
+ return net_crc32(ep, ETH_ALEN) >> 26;
}
QemuOptsList qemu_netdev_opts = {