On 12/05/2017 05:17 AM, Mark Cave-Ayland wrote:
> 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.
>
> Then remove the existing implementation from compute_mcast_idx() and call the
> new function in its place.
>
> Signed-off-by: Mark Cave-Ayland <mark.cave-ayl...@ilande.co.uk>
Reviewed-by: Philippe Mathieu-Daudé <f4...@amsat.org>
> ---
> include/net/net.h | 3 ++-
> net/net.c | 16 +++++++++++-----
> 2 files changed, 13 insertions(+), 6 deletions(-)
>
> diff --git a/include/net/net.h b/include/net/net.h
> index 1c55a93588..586098cb94 100644
> --- a/include/net/net.h
> +++ b/include/net/net.h
> @@ -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) \
> diff --git a/net/net.c b/net/net.c
> index 39ef546708..02a567c18f 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, 6) >> 26;
> }
>
> QemuOptsList qemu_netdev_opts = {
>
