Re: [PATCH 01/13] net: Add l_net_clear_host_bits utility

[Denis Kenzior <denkenz at gmail.com>]

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Hi Andrew,

On 5/5/22 18:15, Andrew Zaborowski wrote:
> Add function that zeros bits after prefix_len'th bit in an address.  Put
> it in net.h so it can be use by both netconfig.c and icmp6.c,
> potentially others.
> ---
>   ell/net.h | 13 +++++++++++++
>   1 file changed, 13 insertions(+)
> 
> diff --git a/ell/net.h b/ell/net.h
> index 0521d75..e193eef 100644
> --- a/ell/net.h
> +++ b/ell/net.h
> @@ -61,6 +61,19 @@ static inline bool l_net_prefix_matches(const void *a, const void *b,
>   	return !bits || ((left ^ right) & (0xff00u >> bits)) == 0;
>   }
>   
> +static inline void l_net_clear_host_bits(uint8_t *address, uint8_t prefix_len,
> +						uint8_t bytes)

I'm not super excited about the naming.  What about l_net_prefix_from_address()? 
  Alternatively, we do have net-private.h where we can stuff this for now and 
not expose it to public API.

> +{
> +	uint8_t last_byte = prefix_len / 8;
> +
> +	if (prefix_len & 7) {
> +		address[last_byte] &= 0xff00 >> (prefix_len & 7);
> +		last_byte++;
> +	}
> +
> +	memset(address + last_byte, 0, bytes - last_byte);
> +}
> +
>   #ifdef __cplusplus
>   }
>   #endif
> 

Regards,
-Denis