Re: [PATCH v7 1/4] tcp: Encode checksum computation flags in a single parameter

[Laurent Vivier <lvivier@redhat.com>]

On 5/26/26 10:37, Stefano Brivio wrote:
> On Wed, 20 May 2026 17:10:07 +0200
> Laurent Vivier <lvivier@redhat.com> wrote:
> 
>> tcp_fill_headers() takes a pointer to a previously computed IPv4 header
>> checksum to avoid recalculating it when the payload length doesn't
>> change, and a separate bool to skip TCP checksum computation.
>>
>> Replace both parameters with a single uint32_t csum_flags that encodes:
>> - IP4_CSUM (bit 31): compute IPv4 header checksum from scratch
>> - TCP_CSUM (bit 30): compute TCP checksum
>> - IP4_CMASK (low 16 bits): cached IPv4 header checksum value
> 
> Have you considered something like:
> 
> struct csum_state {
> 	bool compute_tcp;
> 	bool compute_ip;
> 	uint16_t computed_ip;
> };
> 
> ? I think the related documentation would look simpler and it should
> also be more robust to future changes.
> 
> Not worth a respin though, if it looks like a good idea I guess it could
> be done as a follow-up.
> 

Yes, I think it's a good idea. It looks cleaner.

Thanks,
Laurent