Re: [PATCH mptcp-next 1/4] mptcp: prefer ip address in syn skb instead of listen sk bound address

[Paolo Abeni <pabeni@redhat.com>]

On Thu, 2022-02-10 at 16:29 +0100, Florian Westphal wrote:
> Once we change mptcp to use tproxy-like scheme to steer mptcp join
> requests to a special pernet socket, the 'sk bound address' becomes
> meaningless because it will never be identical to the tcp dport/ip daddr
> of the on-wire packet.
> 
> Prepare for this: pass the skbuff and use the packet data instead of
> the address the listener socket is bound to.
> 
> Signed-off-by: Florian Westphal <fw@strlen.de>
> ---
>  net/mptcp/pm_netlink.c | 17 +++++++++++++++--
>  net/mptcp/protocol.h   |  2 +-
>  net/mptcp/subflow.c    |  5 +++--
>  3 files changed, 19 insertions(+), 5 deletions(-)
> 
> diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
> index 98b485406afa..1696f6fb9baa 100644
> --- a/net/mptcp/pm_netlink.c
> +++ b/net/mptcp/pm_netlink.c
> @@ -279,13 +279,26 @@ mptcp_lookup_anno_list_by_saddr(struct mptcp_sock *msk,
>  	return NULL;
>  }
>  
> -bool mptcp_pm_sport_in_anno_list(struct mptcp_sock *msk, const struct sock *sk)
> +static void skb_address(const struct sk_buff *skb,
> +			struct mptcp_addr_info *addr)

Very minor nit: I would rename the above helper to something more
expressive, alike skb_fetch_src_address() or the like.


/P