Re: [PATCH 05/14] Add csum_ip4_header() helper to calculate IPv4 header checksums

[Stefano Brivio <sbrivio@redhat.com>]

On Mon, 17 Oct 2022 19:57:58 +1100
David Gibson <david@gibson.dropbear.id.au> wrote:

> We calculate IPv4 header checksums in at least two places, in dhcp() and
> in tap_ip_send.  Add a helper to handle this calculation in both places.
> 
> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
> ---
>  checksum.c | 6 ++++++
>  checksum.h | 1 +
>  dhcp.c     | 3 +--
>  tap.c      | 3 +--
>  4 files changed, 9 insertions(+), 4 deletions(-)
> 
> diff --git a/checksum.c b/checksum.c
> index 72f1cfb..f25a96a 100644
> --- a/checksum.c
> +++ b/checksum.c
> @@ -114,6 +114,12 @@ uint16_t csum_unaligned(const void *buf, size_t len, uint32_t init)
>  	return (uint16_t)~csum_fold(sum_16b(buf, len) + init);
>  }
>  

/**
 * csum_ip4_header() - Calculate and set IPv4 header checksum
 * @iph:	IPv4 header
 */

...I just tried to run Doxygen, I think it would be nice to have
eventually (especially for DOT call graphs), things don't look too bad.

> +void csum_ip4_header(struct iphdr *ip4hr)
> +{
> +	ip4hr->check = 0;
> +	ip4hr->check = csum_unaligned(ip4hr, (size_t)ip4hr->ihl * 4, 0);

iph, for consistency.

-- 
Stefano