Re: [MPTCP][PATCH v5 mptcp-next 1/5] mptcp: MP_FAIL suboption sending

[Paolo Abeni <pabeni@redhat.com>]

On Mon, 2021-07-26 at 14:45 +0800, Geliang Tang wrote:
> From: Geliang Tang <geliangtang@xiaomi.com>
> 
> This patch added the MP_FAIL suboption sending support.
> 
> Add a new flag named send_mp_fail in struct mptcp_subflow_context. If
> this flag is set, send out MP_FAIL suboption.
> 
> Add a new member fail_seq in struct mptcp_out_options to save the data
> sequence number to put into the MP_FAIL suboption.
> 
> An MP_FAIL option could be included in a RST or on the subflow-level
> ACK.
> 
> Signed-off-by: Geliang Tang <geliangtang@xiaomi.com>
> ---
>  include/net/mptcp.h  |  5 +++-
>  net/mptcp/options.c  | 61 +++++++++++++++++++++++++++++++++++++++++---
>  net/mptcp/protocol.h |  3 +++
>  3 files changed, 64 insertions(+), 5 deletions(-)
> 
> diff --git a/include/net/mptcp.h b/include/net/mptcp.h
> index d0b9e4a7121f..6c8c8592153d 100644
> --- a/include/net/mptcp.h
> +++ b/include/net/mptcp.h
> @@ -60,7 +60,10 @@ struct mptcp_out_options {
>  	u16 suboptions;
>  	u64 sndr_key;
>  	u64 rcvr_key;
> -	u64 ahmac;
> +	union {
> +		u64 ahmac;
> +		u64 fail_seq;
> +	};
>  	struct mptcp_addr_info local;
>  	struct mptcp_addr_info remote;
>  	struct mptcp_rm_list rm_list;

This will conflict with: "mptcp: shrink mptcp_out_options struct". If
this series is merged before the "mptcp: shrink mptcp_out_options
struct" series, I think we can just add the new field here without any
union and do the aliasing the the shirnk' patch.

Otherwise ("mptcp: shrink mptcp_out_options struct" merged first), I
think:

		struct mptcp_ext ext_copy;

should be replace with:
		struct {
			struct mptcp_ext ext_copy;
			u64 ahmac;
		};

mptcp_out_options should not change size that way.

Cheers

Paolo