Commit eaba8f34 authored by Mark Cave-Ayland's avatar Mark Cave-Ayland Committed by Jason Wang
Browse files

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: default avatarMark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: default avatarPhilippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: default avatarJason Wang <jasowang@redhat.com>
parent d62644b4

hw/net/eepro100.c

+1 −3
Original line number Diff line number Diff line
@@ -323,8 +323,6 @@ static const uint16_t eepro100_mdi_mask[] = { 
    0xffff, 0xffff, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,

};



#define POLYNOMIAL 0x04c11db6



static E100PCIDeviceInfo *eepro100_get_class(EEPRO100State *s);



/* From FreeBSD (locally modified). */
@@ -342,7 +340,7 @@ static unsigned e100_compute_mcast_idx(const uint8_t *ep) 
            crc <<= 1;

            b >>= 1;

            if (carry) {

                crc = ((crc ^ POLYNOMIAL) | carry);

                crc = ((crc ^ POLYNOMIAL_BE) | carry);

            }

        }

    }

include/net/net.h

+2 −1
Original line number Diff line number Diff line
@@ -227,7 +227,8 @@ NetClientState *net_hub_port_find(int hub_id); 


void qdev_set_nic_properties(DeviceState *dev, NICInfo *nd);



#define POLYNOMIAL 0x04c11db6

#define POLYNOMIAL_BE 0x04c11db6

uint32_t net_crc32(const uint8_t *p, int len);

unsigned compute_mcast_idx(const uint8_t *ep);



#define vmstate_offset_macaddr(_state, _field)                       \

net/net.c

+11 −5
Original line number Diff line number Diff line
@@ -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;

}

    return crc >> 26;



unsigned compute_mcast_idx(const uint8_t *ep)

{

    return net_crc32(ep, ETH_ALEN) >> 26;

}



QemuOptsList qemu_netdev_opts = {