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net: introduce net_crc32_le() function

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This provides a standard ethernet CRC32 little-endian implementation.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Jason Wang <jasowang@redhat.com>
This commit is contained in:
Mark Cave-Ayland 2017-12-15 18:41:44 +00:00 • committed by Jason Wang
parent eaba8f34f0
commit f1a7deb900
2 changed files with 24 additions and 0 deletions
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2
include/net/net.h
View file

@ -228,7 +228,9 @@ NetClientState *net_hub_port_find(int hub_id);
void qdev_set_nic_properties(DeviceState *dev, NICInfo *nd); void qdev_set_nic_properties(DeviceState *dev, NICInfo *nd);
#define POLYNOMIAL_BE 0x04c11db6 #define POLYNOMIAL_BE 0x04c11db6
#define POLYNOMIAL_LE 0xedb88320
uint32_t net_crc32(const uint8_t *p, int len); uint32_t net_crc32(const uint8_t *p, int len);
uint32_t net_crc32_le(const uint8_t *p, int len);
unsigned compute_mcast_idx(const uint8_t *ep); unsigned compute_mcast_idx(const uint8_t *ep);
#define vmstate_offset_macaddr(_state, _field) \ #define vmstate_offset_macaddr(_state, _field) \

22
net/net.c
View file

@ -1603,6 +1603,28 @@ uint32_t net_crc32(const uint8_t *p, int len)
return crc; return crc;
} }
uint32_t net_crc32_le(const uint8_t *p, int len)
{
uint32_t crc;
int carry, i, j;
uint8_t b;
crc = 0xffffffff;
for (i = 0; i < len; i++) {
b = *p++;
for (j = 0; j < 8; j++) {
carry = (crc & 0x1) ^ (b & 0x01);
crc >>= 1;
b >>= 1;
if (carry) {
crc ^= POLYNOMIAL_LE;
}
}
}
return crc;
}
unsigned compute_mcast_idx(const uint8_t *ep) unsigned compute_mcast_idx(const uint8_t *ep)
{ {
return net_crc32(ep, ETH_ALEN) >> 26; return net_crc32(ep, ETH_ALEN) >> 26;