Re: [PATCH mptcp-net v4 22/23] mptcp: pm: reuse ID 0 after delete and re-add

[Mat Martineau <martineau@kernel.org>]

On Mon, 22 Jul 2024, Matthieu Baerts (NGI0) wrote:

> When the endpoint used by the initial subflow is removed and re-added
> later, the PM has to force the ID 0, it is a special case imposed by the
> MPTCP specs.
>
> Note that the endpoint should then need to be re-added reusing the same
> ID.
>
> Fixes: 3ad14f54bd74 ("mptcp: more accurate MPC endpoint tracking")
> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
> ---
> net/mptcp/pm_netlink.c | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
> diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
> index 8f25690a5edc..45a1aa0a40bf 100644
> --- a/net/mptcp/pm_netlink.c
> +++ b/net/mptcp/pm_netlink.c
> @@ -586,6 +586,11 @@ static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk)
>
> 		__clear_bit(local.addr.id, msk->pm.id_avail_bitmap);
> 		msk->pm.add_addr_signaled++;
> +
> +		/* Special case for ID0: set the correct */

"set the correct ID" ?

> +		if (local.addr.id == msk->mpc_endpoint_id)
> +			local.addr.id = 0;
> +
> 		mptcp_pm_announce_addr(msk, &local.addr, false);
> 		mptcp_pm_nl_addr_send_ack(msk);
>
> @@ -614,6 +619,10 @@ static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk)
> 		if (nr == 0)
> 			continue;
>
> +		/* Special case for ID0: set the correct ID */
> +		if (local.addr.id == msk->mpc_endpoint_id)
> +			local.addr.id = 0;
> +
> 		spin_unlock_bh(&msk->pm.lock);
> 		for (i = 0; i < nr; i++)
> 			__mptcp_subflow_connect(sk, &local.addr, &addrs[i]);
>
> -- 
> 2.45.2
>
>
>