Re: [PATCH mptcp-iproute2-net v2] mptcp: add new listener events

[Mat Martineau <mathew.j.martineau@linux.intel.com>]

On Wed, 4 Jan 2023, Matthieu Baerts wrote:

> These new events have been added in kernel commit f8c9dfbd875b ("mptcp:
> add pm listener events") by Geliang Tang.
>
> Two new MPTCP Netlink event types for PM listening socket creation and
> closure have been recently added. They will be available in the future
> v6.2 kernel.
>
> They have been added because MPTCP for Linux, when not using the
> in-kernel PM, depends on the userspace PM to create extra listening
> sockets -- called "PM listeners" -- before announcing addresses and
> ports. With the existing MPTCP Netlink events, a userspace PM can create
> PM listeners at startup time, or in response to an incoming connection.
> Creating sockets in response to connections is not optimal: ADD_ADDRs
> can't be sent until the sockets are created and listen()ed, and if all
> connections are closed then it may not be clear to the userspace PM
> daemon that PM listener sockets should be cleaned up. Hence these new
> events: PM listening sockets can be managed based on application
> activity.
>
> Note that the maximum event string size has to be increased by 2 to be
> able to display LISTENER_CREATED without trunking it.

s/trunking/truncated/

Other than that, looks good!

Acked-by: Mat Martineau <mathew.j.martineau@linux.intel.com>

>
> Also, as pointed by Mat, this event doesn't have any "token" attribute
> so this attribute is now printed only if it is available.
>
> Link: https://github.com/multipath-tcp/mptcp_net-next/issues/313
> Cc: Geliang Tang <geliang.tang@suse.com>
> Cc: Mat Martineau <mathew.j.martineau@linux.intel.com>
> Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
> ---
>
> Notes:
>    v1 -> v2:
>      - print LISTENER_* instead of LISTEN_* and increase the limit to 16
>        chars (Mat)
>      - check if the TOKEN attribute is available before printing it (Mat)
>      - edit the commit message to reflect the modifications from v2
>
> ip/ipmptcp.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/ip/ipmptcp.c b/ip/ipmptcp.c
> index ce62ab9a..beba7a41 100644
> --- a/ip/ipmptcp.c
> +++ b/ip/ipmptcp.c
> @@ -454,6 +454,8 @@ static const char * const event_to_str[] = {
> 	[MPTCP_EVENT_SUB_ESTABLISHED] = "SF_ESTABLISHED",
> 	[MPTCP_EVENT_SUB_CLOSED] = "SF_CLOSED",
> 	[MPTCP_EVENT_SUB_PRIORITY] = "SF_PRIO",
> +	[MPTCP_EVENT_LISTENER_CREATED] = "LISTENER_CREATED",
> +	[MPTCP_EVENT_LISTENER_CLOSED] = "LISTENER_CLOSED",
> };
>
> static void print_addr(const char *key, int af, struct rtattr *value)
> @@ -492,11 +494,12 @@ static int mptcp_monitor_msg(struct rtnl_ctrl_data *ctrl,
> 		goto out;
> 	}
>
> -	printf("[%14s]", event_to_str[ghdr->cmd]);
> +	printf("[%16s]", event_to_str[ghdr->cmd]);
>
> 	parse_rtattr(tb, MPTCP_ATTR_MAX, (void *) ghdr + GENL_HDRLEN, len);
>
> -	printf(" token=%08x", rta_getattr_u32(tb[MPTCP_ATTR_TOKEN]));
> +	if (tb[MPTCP_ATTR_TOKEN])
> +		printf(" token=%08x", rta_getattr_u32(tb[MPTCP_ATTR_TOKEN]));
>
> 	if (tb[MPTCP_ATTR_REM_ID])
> 		printf(" remid=%u", rta_getattr_u8(tb[MPTCP_ATTR_REM_ID]));
>
> base-commit: d0e02f35af33b8957cc9f52af07b0b81d557ad3b
> -- 
> 2.37.2
>
>

--
Mat Martineau
Intel