Subject: Re: [RFC ipsec-next v2 2/8] iptfs: uapi: ip: add ip_tfs_*_hdr packet formats

From: Sabrina Dubroca <[email-masked]>
Date: Mon, 20 Nov 2023 16:28:54 +0100

2023-11-12, 22:52:13 -0500, Christian Hopps wrote:
> From: Christian Hopps <[email-masked]>
> 
> Add the on-wire basic and congestion-control IP-TFS packet headers.
> 
> Signed-off-by: Christian Hopps <[email-masked]>
> ---
>  include/uapi/linux/ip.h | 17 +++++++++++++++++
>  1 file changed, 17 insertions(+)
>
> diff --git a/include/uapi/linux/ip.h b/include/uapi/linux/ip.h
> index 283dec7e3645..cc83878ecf08 100644
> --- a/include/uapi/linux/ip.h
> +++ b/include/uapi/linux/ip.h
> @@ -137,6 +137,23 @@ struct ip_beet_phdr {
>  	__u8 reserved;
>  };
>  
> +struct ip_iptfs_hdr {
> +	__u8 subtype;		/* 0*: basic, 1: CC */
> +	__u8 flags;
> +	__be16 block_offset;
> +};
> +
> +struct ip_iptfs_cc_hdr {
> +	__u8 subtype;		/* 0: basic, 1*: CC */
> +	__u8 flags;
> +	__be16 block_offset;
> +	__be32 loss_rate;
> +	__u8 rtt_and_adelay1[4];
> +	__u8 adelay2_and_xdelay[4];

Given how the fields are split, wouldn't it be more convenient to have
a single __be64, rather than reading some bits from multiple __u8?

> +	__be32 tval;
> +	__be32 techo;
> +};

I don't think these need to be part of uapi. Can we move them to
include/net/iptfs.h (or possibly net/xfrm/xfrm_iptfs.c)? It would also
make more sense to have them near the definitions for
IPTFS_SUBTYPE_*. And it would be easier to change how we split and
name fields for kernel consumption if we're not stuck with whatever we
put in uapi.

-- 
Sabrina