Commit f1a7deb9 authored by Mark Cave-Ayland's avatar Mark Cave-Ayland Committed by Jason Wang
Browse files

net: introduce net_crc32_le() function 



This provides a standard ethernet CRC32 little-endian implementation.

Signed-off-by: default avatarMark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: default avatarEric Blake <eblake@redhat.com>
Reviewed-by: default avatarPhilippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: default avatarJason Wang <jasowang@redhat.com>
parent eaba8f34

include/net/net.h

+2 −0
Original line number Diff line number Diff line
@@ -228,7 +228,9 @@ NetClientState *net_hub_port_find(int hub_id); 
void qdev_set_nic_properties(DeviceState *dev, NICInfo *nd);



#define POLYNOMIAL_BE 0x04c11db6

#define POLYNOMIAL_LE 0xedb88320

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);



#define vmstate_offset_macaddr(_state, _field)                       \

net/net.c

+22 −0
Original line number Diff line number Diff line
@@ -1603,6 +1603,28 @@ uint32_t net_crc32(const uint8_t *p, int len) 
    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)

{

    return net_crc32(ep, ETH_ALEN) >> 26;