Merge branch 'mptcp-add-last-time-fields-in-mptcp_info'

Matthieu Baerts says:

====================
mptcp: add last time fields in mptcp_info

These patches from Geliang add support for the "last time" field in
MPTCP Info, and verify that the counters look valid.

Patch 1 adds these counters: last_data_sent, last_data_recv and
last_ack_recv. They are available in the MPTCP Info, so exposed via
getsockopt(MPTCP_INFO) and the Netlink Diag interface.

Patch 2 adds a test in diag.sh MPTCP selftest, to check that the
counters have moved by at least 250ms, after having waited twice that
time.

v1: https://lore.kernel.org/r/20240405-upstream-net-next-20240405-mptcp-last-time-info-v1-0-52dc49453649@kernel.org
====================

Link: https://lore.kernel.org/r/20240410-upstream-net-next-20240405-mptcp-last-time-info-v2-0-f95bd6b33e51@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

6 files changed, 79 insertions, 5 deletions

diff --git a/include/uapi/linux/mptcp.h b/include/uapi/linux/mptcp.h
index 74cfe496891e..67d015df8893 100644
--- a/include/uapi/linux/mptcp.h
+++ b/include/uapi/linux/mptcp.h
@@ -58,6 +58,10 @@ struct mptcp_info {
 	__u64	mptcpi_bytes_received;
 	__u64	mptcpi_bytes_acked;
 	__u8	mptcpi_subflows_total;
+	__u8	reserved[3];
+	__u32	mptcpi_last_data_sent;
+	__u32	mptcpi_last_data_recv;
+	__u32	mptcpi_last_ack_recv;
 };
 
 /* MPTCP Reset reason codes, rfc8684 */
diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index 27ca42c77b02..8e8dcfbc2993 100644
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c
@@ -1068,6 +1068,7 @@ static void ack_update_msk(struct mptcp_sock *msk,
 		__mptcp_snd_una_update(msk, new_snd_una);
 		__mptcp_data_acked(sk);
 	}
+	msk->last_ack_recv = tcp_jiffies32;
 	mptcp_data_unlock(sk);
 
 	trace_ack_update_msk(mp_opt->data_ack,
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 995b53cd021c..f8bc34f0d973 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -706,6 +706,8 @@ static bool __mptcp_move_skbs_from_subflow(struct mptcp_sock *msk,
 		}
 	} while (more_data_avail);
 
+	if (moved > 0)
+		msk->last_data_recv = tcp_jiffies32;
 	*bytes += moved;
 	return done;
 }
@@ -1556,6 +1558,8 @@ static int __subflow_push_pending(struct sock *sk, struct sock *ssk,
 	err = copied;
 
 out:
+	if (err > 0)
+		msk->last_data_sent = tcp_jiffies32;
 	return err;
 }
 
@@ -2793,6 +2797,9 @@ static void __mptcp_init_sock(struct sock *sk)
 	WRITE_ONCE(msk->allow_infinite_fallback, true);
 	msk->recovery = false;
 	msk->subflow_id = 1;
+	msk->last_data_sent = tcp_jiffies32;
+	msk->last_data_recv = tcp_jiffies32;
+	msk->last_ack_recv = tcp_jiffies32;
 
 	mptcp_pm_data_init(msk);
 
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 46f4655b7123..fdfa843e2d88 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -282,6 +282,9 @@ struct mptcp_sock {
 	u64		bytes_acked;
 	u64		snd_una;
 	u64		wnd_end;
+	u32		last_data_sent;
+	u32		last_data_recv;
+	u32		last_ack_recv;
 	unsigned long	timer_ival;
 	u32		token;
 	int		rmem_released;
diff --git a/net/mptcp/sockopt.c b/net/mptcp/sockopt.c
index 9d5d42a77bcc..1fea43f5b6f3 100644
--- a/net/mptcp/sockopt.c
+++ b/net/mptcp/sockopt.c
@@ -898,6 +898,7 @@ void mptcp_diag_fill_info(struct mptcp_sock *msk, struct mptcp_info *info)
 	struct sock *sk = (struct sock *)msk;
 	u32 flags = 0;
 	bool slow;
+	u32 now;
 
 	memset(info, 0, sizeof(*info));
 
@@ -926,11 +927,6 @@ void mptcp_diag_fill_info(struct mptcp_sock *msk, struct mptcp_info *info)
 	if (READ_ONCE(msk->can_ack))
 		flags |= MPTCP_INFO_FLAG_REMOTE_KEY_RECEIVED;
 	info->mptcpi_flags = flags;
-	mptcp_data_lock(sk);
-	info->mptcpi_snd_una = msk->snd_una;
-	info->mptcpi_rcv_nxt = msk->ack_seq;
-	info->mptcpi_bytes_acked = msk->bytes_acked;
-	mptcp_data_unlock(sk);
 
 	slow = lock_sock_fast(sk);
 	info->mptcpi_csum_enabled = READ_ONCE(msk->csum_enabled);
@@ -942,7 +938,17 @@ void mptcp_diag_fill_info(struct mptcp_sock *msk, struct mptcp_info *info)
 	info->mptcpi_bytes_retrans = msk->bytes_retrans;
 	info->mptcpi_subflows_total = info->mptcpi_subflows +
 		__mptcp_has_initial_subflow(msk);
+	now = tcp_jiffies32;
+	info->mptcpi_last_data_sent = jiffies_to_msecs(now - msk->last_data_sent);
+	info->mptcpi_last_data_recv = jiffies_to_msecs(now - msk->last_data_recv);
 	unlock_sock_fast(sk, slow);
+
+	mptcp_data_lock(sk);
+	info->mptcpi_last_ack_recv = jiffies_to_msecs(now - msk->last_ack_recv);
+	info->mptcpi_snd_una = msk->snd_una;
+	info->mptcpi_rcv_nxt = msk->ack_seq;
+	info->mptcpi_bytes_acked = msk->bytes_acked;
+	mptcp_data_unlock(sk);
 }
 EXPORT_SYMBOL_GPL(mptcp_diag_fill_info);
 
diff --git a/tools/testing/selftests/net/mptcp/diag.sh b/tools/testing/selftests/net/mptcp/diag.sh
index bc97ab33a00e..776d43a6922d 100755
--- a/tools/testing/selftests/net/mptcp/diag.sh
+++ b/tools/testing/selftests/net/mptcp/diag.sh
@@ -200,6 +200,58 @@ chk_msk_cestab()
 		 "${expected}" "${msg}" ""
 }
 
+msk_info_get_value()
+{
+	local port="${1}"
+	local info="${2}"
+
+	ss -N "${ns}" -inHM dport "${port}" | \
+		mptcp_lib_get_info_value "${info}" "${info}"
+}
+
+chk_msk_info()
+{
+	local port="${1}"
+	local info="${2}"
+	local cnt="${3}"
+	local msg="....chk ${info}"
+	local delta_ms=250  # half what we waited before, just to be sure
+	local now
+
+	now=$(msk_info_get_value "${port}" "${info}")
+
+	mptcp_lib_print_title "${msg}"
+	if { [ -z "${cnt}" ] || [ -z "${now}" ]; } &&
+	   ! mptcp_lib_expect_all_features; then
+		mptcp_lib_pr_skip "Feature probably not supported"
+		mptcp_lib_result_skip "${msg}"
+	elif [ "$((cnt + delta_ms))" -lt "${now}" ]; then
+		mptcp_lib_pr_ok
+		mptcp_lib_result_pass "${msg}"
+	else
+		mptcp_lib_pr_fail "value of ${info} changed by $((now - cnt))ms," \
+				  "expected at least ${delta_ms}ms"
+		mptcp_lib_result_fail "${msg}"
+		ret=${KSFT_FAIL}
+	fi
+}
+
+chk_last_time_info()
+{
+	local port="${1}"
+	local data_sent data_recv ack_recv
+
+	data_sent=$(msk_info_get_value "${port}" "last_data_sent")
+	data_recv=$(msk_info_get_value "${port}" "last_data_recv")
+	ack_recv=$(msk_info_get_value "${port}" "last_ack_recv")
+
+	sleep 0.5  # wait to check after if the timestamps difference
+
+	chk_msk_info "${port}" "last_data_sent" "${data_sent}"
+	chk_msk_info "${port}" "last_data_recv" "${data_recv}"
+	chk_msk_info "${port}" "last_ack_recv" "${ack_recv}"
+}
+
 wait_connected()
 {
 	local listener_ns="${1}"
@@ -233,6 +285,7 @@ echo "b" | \
 				127.0.0.1 >/dev/null &
 wait_connected $ns 10000
 chk_msk_nr 2 "after MPC handshake "
+chk_last_time_info 10000
 chk_msk_remote_key_nr 2 "....chk remote_key"
 chk_msk_fallback_nr 0 "....chk no fallback"
 chk_msk_inuse 2