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Re: [Qemu-devel] [PATCHv2 2/5] net: introduce net_crc32_le() function
From: |
Philippe Mathieu-Daudé |
Subject: |
Re: [Qemu-devel] [PATCHv2 2/5] net: introduce net_crc32_le() function |
Date: |
Wed, 6 Dec 2017 00:27:36 -0300 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.4.0 |
On 12/05/2017 05:17 AM, Mark Cave-Ayland wrote:
> This provides a standard ethernet CRC32 little-endian implementation.
>
> Signed-off-by: Mark Cave-Ayland <address@hidden>
Reviewed-by: Philippe Mathieu-Daudé <address@hidden>
> ---
> include/net/net.h | 2 ++
> net/net.c | 22 ++++++++++++++++++++++
> 2 files changed, 24 insertions(+)
>
> diff --git a/include/net/net.h b/include/net/net.h
> index 586098cb94..4afac1a9dd 100644
> --- a/include/net/net.h
> +++ b/include/net/net.h
> @@ -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) \
> diff --git a/net/net.c b/net/net.c
> index 02a567c18f..38008fe8e7 100644
> --- a/net/net.c
> +++ b/net/net.c
> @@ -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 = crc ^ POLYNOMIAL_LE;
> + }
> + }
> + }
> +
> + return crc;
> +}
> +
> unsigned compute_mcast_idx(const uint8_t *ep)
> {
> return net_crc32(ep, 6) >> 26;
>