mptcp: add last time fields in mptcp_info

This patch adds "last time" fields last_data_sent, last_data_recv and
last_ack_recv in struct mptcp_sock to record the last time data_sent,
data_recv and ack_recv happened. They all are initialized as
tcp_jiffies32 in __mptcp_init_sock(), and updated as tcp_jiffies32 too
when data is sent in __subflow_push_pending(), data is received in
__mptcp_move_skbs_from_subflow(), and ack is received in ack_update_msk().

Similar to tcpi_last_data_sent, tcpi_last_data_recv and tcpi_last_ack_recv
exposed with TCP, this patch exposes the last time "an action happened" for
MPTCP in mptcp_info, named mptcpi_last_data_sent, mptcpi_last_data_recv and
mptcpi_last_ack_recv, calculated in mptcp_diag_fill_info() as the time
deltas between now and the newly added last time fields in mptcp_sock.

Since msk->last_ack_recv needs to be protected by mptcp_data_lock/unlock,
and lock_sock_fast can sleep and be quite slow, move the entire
mptcp_data_lock/unlock block after the lock/unlock_sock_fast block.
Then mptcpi_last_data_sent and mptcpi_last_data_recv are set in
lock/unlock_sock_fast block, while mptcpi_last_ack_recv is set in
mptcp_data_lock/unlock block, which is protected by a spinlock and
should not block for too long.

Also add three reserved bytes in struct mptcp_info not to have holes in
this structure exposed to userspace.

Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/446
Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://lore.kernel.org/r/20240410-upstream-net-next-20240405-mptcp-last-time-info-v2-1-f95bd6b33e51@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

0 files changed, 0 insertions, 0 deletions