Merge branch 'selftests-mptcp-counter-cache-stats-before-timeout'

Matthieu Baerts says:

====================
selftests: mptcp: counter cache & stats before timeout

Here are a bunch of small improvements to the MPTCP selftests:

- Patch 1: move code to mptcp_lib.sh to prepare the new features.

- Patch 2: simplify mptcp_lib_pr_err_stats helper use.

- Patch 3: remove unused last column from nstat output.

- Patch 4: improve stats dump in mptcp_join.sh.

- Patch 5: get counters from nstat history and simplify mptcp_connect.sh.

- Patch 6: avoid taking the same packet trace twice.

- Patch 7: wait for an event instead of a fix time.

- Patch 8: instead of using 'timeout' and print the stats after, another
  internal timeout is used: if it fires, it will print stats, then stop
  everything. This avoids confusions around stats in case of timeout.
====================

Link: https://patch.msgid.link/20251114-net-next-mptcp-sft-count-cache-stats-timeout-v1-0-863cb04e1b7b@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

6 files changed, 208 insertions, 155 deletions

diff --git a/tools/testing/selftests/net/mptcp/mptcp_connect.sh b/tools/testing/selftests/net/mptcp/mptcp_connect.sh
index 9b7b93f8eb0c..a6447f7a31fe 100755
--- a/tools/testing/selftests/net/mptcp/mptcp_connect.sh
+++ b/tools/testing/selftests/net/mptcp/mptcp_connect.sh
@@ -375,81 +375,75 @@ do_transfer()
 		local capfile="${rndh}-${connector_ns:0:3}-${listener_ns:0:3}-${cl_proto}-${srv_proto}-${connect_addr}-${port}"
 		local capopt="-i any -s 65535 -B 32768 ${capuser}"
 
-		ip netns exec ${listener_ns}  tcpdump ${capopt} -w "${capfile}-listener.pcap"  >> "${capout}" 2>&1 &
+		ip netns exec ${listener_ns} tcpdump ${capopt} \
+			-w "${capfile}-listener.pcap" >> "${capout}" 2>&1 &
 		local cappid_listener=$!
 
-		ip netns exec ${connector_ns} tcpdump ${capopt} -w "${capfile}-connector.pcap" >> "${capout}" 2>&1 &
-		local cappid_connector=$!
+		if [ ${listener_ns} != ${connector_ns} ]; then
+			ip netns exec ${connector_ns} tcpdump ${capopt} \
+				-w "${capfile}-connector.pcap" >> "${capout}" 2>&1 &
+			local cappid_connector=$!
+		fi
 
 		sleep 1
 	fi
 
-	NSTAT_HISTORY=/tmp/${listener_ns}.nstat ip netns exec ${listener_ns} \
-		nstat -n
+	mptcp_lib_nstat_init "${listener_ns}"
 	if [ ${listener_ns} != ${connector_ns} ]; then
-		NSTAT_HISTORY=/tmp/${connector_ns}.nstat ip netns exec ${connector_ns} \
-			nstat -n
-	fi
-
-	local stat_synrx_last_l
-	local stat_ackrx_last_l
-	local stat_cookietx_last
-	local stat_cookierx_last
-	local stat_csum_err_s
-	local stat_csum_err_c
-	local stat_tcpfb_last_l
-	stat_synrx_last_l=$(mptcp_lib_get_counter "${listener_ns}" "MPTcpExtMPCapableSYNRX")
-	stat_ackrx_last_l=$(mptcp_lib_get_counter "${listener_ns}" "MPTcpExtMPCapableACKRX")
-	stat_cookietx_last=$(mptcp_lib_get_counter "${listener_ns}" "TcpExtSyncookiesSent")
-	stat_cookierx_last=$(mptcp_lib_get_counter "${listener_ns}" "TcpExtSyncookiesRecv")
-	stat_csum_err_s=$(mptcp_lib_get_counter "${listener_ns}" "MPTcpExtDataCsumErr")
-	stat_csum_err_c=$(mptcp_lib_get_counter "${connector_ns}" "MPTcpExtDataCsumErr")
-	stat_tcpfb_last_l=$(mptcp_lib_get_counter "${listener_ns}" "MPTcpExtMPCapableFallbackACK")
-
-	timeout ${timeout_test} \
-		ip netns exec ${listener_ns} \
-			./mptcp_connect -t ${timeout_poll} -l -p $port -s ${srv_proto} \
-				$extra_args $local_addr < "$sin" > "$sout" &
+		mptcp_lib_nstat_init "${connector_ns}"
+	fi
+
+	ip netns exec ${listener_ns} \
+		./mptcp_connect -t ${timeout_poll} -l -p $port -s ${srv_proto} \
+			$extra_args $local_addr < "$sin" > "$sout" &
 	local spid=$!
 
 	mptcp_lib_wait_local_port_listen "${listener_ns}" "${port}"
 
 	local start
 	start=$(date +%s%3N)
-	timeout ${timeout_test} \
-		ip netns exec ${connector_ns} \
-			./mptcp_connect -t ${timeout_poll} -p $port -s ${cl_proto} \
-				$extra_args $connect_addr < "$cin" > "$cout" &
+	ip netns exec ${connector_ns} \
+		./mptcp_connect -t ${timeout_poll} -p $port -s ${cl_proto} \
+			$extra_args $connect_addr < "$cin" > "$cout" &
 	local cpid=$!
 
+	mptcp_lib_wait_timeout "${timeout_test}" "${listener_ns}" \
+		"${connector_ns}" "${port}" "${cpid}" "${spid}" &
+	local timeout_pid=$!
+
 	wait $cpid
 	local retc=$?
 	wait $spid
 	local rets=$?
 
+	if kill -0 $timeout_pid; then
+		# Finished before the timeout: kill the background job
+		mptcp_lib_kill_group_wait $timeout_pid
+		timeout_pid=0
+	fi
+
 	local stop
 	stop=$(date +%s%3N)
 
 	if $capture; then
 		sleep 1
 		kill ${cappid_listener}
-		kill ${cappid_connector}
+		if [ ${listener_ns} != ${connector_ns} ]; then
+			kill ${cappid_connector}
+		fi
 	fi
 
-	NSTAT_HISTORY=/tmp/${listener_ns}.nstat ip netns exec ${listener_ns} \
-		nstat | grep Tcp > /tmp/${listener_ns}.out
+	mptcp_lib_nstat_get "${listener_ns}"
 	if [ ${listener_ns} != ${connector_ns} ]; then
-		NSTAT_HISTORY=/tmp/${connector_ns}.nstat ip netns exec ${connector_ns} \
-			nstat | grep Tcp > /tmp/${connector_ns}.out
+		mptcp_lib_nstat_get "${connector_ns}"
 	fi
 
 	local duration
 	duration=$((stop-start))
 	printf "(duration %05sms) " "${duration}"
-	if [ ${rets} -ne 0 ] || [ ${retc} -ne 0 ]; then
+	if [ ${rets} -ne 0 ] || [ ${retc} -ne 0 ] || [ ${timeout_pid} -ne 0 ]; then
 		mptcp_lib_pr_fail "client exit code $retc, server $rets"
-		mptcp_lib_pr_err_stats "${listener_ns}" "${connector_ns}" "${port}" \
-			"/tmp/${listener_ns}.out" "/tmp/${connector_ns}.out"
+		mptcp_lib_pr_err_stats "${listener_ns}" "${connector_ns}" "${port}"
 
 		echo
 		cat "$capout"
@@ -463,38 +457,38 @@ do_transfer()
 	rets=$?
 
 	local extra=""
-	local stat_synrx_now_l
-	local stat_ackrx_now_l
-	local stat_cookietx_now
-	local stat_cookierx_now
-	local stat_ooo_now
-	local stat_tcpfb_now_l
-	stat_synrx_now_l=$(mptcp_lib_get_counter "${listener_ns}" "MPTcpExtMPCapableSYNRX")
-	stat_ackrx_now_l=$(mptcp_lib_get_counter "${listener_ns}" "MPTcpExtMPCapableACKRX")
-	stat_cookietx_now=$(mptcp_lib_get_counter "${listener_ns}" "TcpExtSyncookiesSent")
-	stat_cookierx_now=$(mptcp_lib_get_counter "${listener_ns}" "TcpExtSyncookiesRecv")
-	stat_ooo_now=$(mptcp_lib_get_counter "${listener_ns}" "TcpExtTCPOFOQueue")
-	stat_tcpfb_now_l=$(mptcp_lib_get_counter "${listener_ns}" "MPTcpExtMPCapableFallbackACK")
-
-	expect_synrx=$((stat_synrx_last_l))
-	expect_ackrx=$((stat_ackrx_last_l))
+	local stat_synrx
+	local stat_ackrx
+	local stat_cookietx
+	local stat_cookierx
+	local stat_ooo
+	local stat_tcpfb
+	stat_synrx=$(mptcp_lib_get_counter "${listener_ns}" "MPTcpExtMPCapableSYNRX")
+	stat_ackrx=$(mptcp_lib_get_counter "${listener_ns}" "MPTcpExtMPCapableACKRX")
+	stat_cookietx=$(mptcp_lib_get_counter "${listener_ns}" "TcpExtSyncookiesSent")
+	stat_cookierx=$(mptcp_lib_get_counter "${listener_ns}" "TcpExtSyncookiesRecv")
+	stat_ooo=$(mptcp_lib_get_counter "${listener_ns}" "TcpExtTCPOFOQueue")
+	stat_tcpfb=$(mptcp_lib_get_counter "${listener_ns}" "MPTcpExtMPCapableFallbackACK")
+
+	expect_synrx=0
+	expect_ackrx=0
 
 	cookies=$(ip netns exec ${listener_ns} sysctl net.ipv4.tcp_syncookies)
 	cookies=${cookies##*=}
 
 	if [ ${cl_proto} = "MPTCP" ] && [ ${srv_proto} = "MPTCP" ]; then
-		expect_synrx=$((stat_synrx_last_l+connect_per_transfer))
-		expect_ackrx=$((stat_ackrx_last_l+connect_per_transfer))
+		expect_synrx=${connect_per_transfer}
+		expect_ackrx=${connect_per_transfer}
 	fi
 
-	if [ ${stat_synrx_now_l} -lt ${expect_synrx} ]; then
-		mptcp_lib_pr_fail "lower MPC SYN rx (${stat_synrx_now_l})" \
+	if [ ${stat_synrx} -lt ${expect_synrx} ]; then
+		mptcp_lib_pr_fail "lower MPC SYN rx (${stat_synrx})" \
 				  "than expected (${expect_synrx})"
 		retc=1
 	fi
-	if [ ${stat_ackrx_now_l} -lt ${expect_ackrx} ]; then
-		if [ ${stat_ooo_now} -eq 0 ]; then
-			mptcp_lib_pr_fail "lower MPC ACK rx (${stat_ackrx_now_l})" \
+	if [ ${stat_ackrx} -lt ${expect_ackrx} ]; then
+		if [ ${stat_ooo} -eq 0 ]; then
+			mptcp_lib_pr_fail "lower MPC ACK rx (${stat_ackrx})" \
 					  "than expected (${expect_ackrx})"
 			rets=1
 		else
@@ -508,47 +502,45 @@ do_transfer()
 		csum_err_s=$(mptcp_lib_get_counter "${listener_ns}" "MPTcpExtDataCsumErr")
 		csum_err_c=$(mptcp_lib_get_counter "${connector_ns}" "MPTcpExtDataCsumErr")
 
-		local csum_err_s_nr=$((csum_err_s - stat_csum_err_s))
-		if [ $csum_err_s_nr -gt 0 ]; then
-			mptcp_lib_pr_fail "server got ${csum_err_s_nr} data checksum error[s]"
+		if [ $csum_err_s -gt 0 ]; then
+			mptcp_lib_pr_fail "server got ${csum_err_s} data checksum error[s]"
 			rets=1
 		fi
 
-		local csum_err_c_nr=$((csum_err_c - stat_csum_err_c))
-		if [ $csum_err_c_nr -gt 0 ]; then
-			mptcp_lib_pr_fail "client got ${csum_err_c_nr} data checksum error[s]"
+		if [ $csum_err_c -gt 0 ]; then
+			mptcp_lib_pr_fail "client got ${csum_err_c} data checksum error[s]"
 			retc=1
 		fi
 	fi
 
-	if [ ${stat_ooo_now} -eq 0 ] && [ ${stat_tcpfb_last_l} -ne ${stat_tcpfb_now_l} ]; then
+	if [ ${stat_ooo} -eq 0 ] && [ ${stat_tcpfb} -gt 0 ]; then
 		mptcp_lib_pr_fail "unexpected fallback to TCP"
 		rets=1
 	fi
 
 	if [ $cookies -eq 2 ];then
-		if [ $stat_cookietx_last -ge $stat_cookietx_now ] ;then
+		if [ $stat_cookietx -eq 0 ] ;then
 			extra+=" WARN: CookieSent: did not advance"
 		fi
-		if [ $stat_cookierx_last -ge $stat_cookierx_now ] ;then
+		if [ $stat_cookierx -eq 0 ] ;then
 			extra+=" WARN: CookieRecv: did not advance"
 		fi
 	else
-		if [ $stat_cookietx_last -ne $stat_cookietx_now ] ;then
+		if [ $stat_cookietx -gt 0 ] ;then
 			extra+=" WARN: CookieSent: changed"
 		fi
-		if [ $stat_cookierx_last -ne $stat_cookierx_now ] ;then
+		if [ $stat_cookierx -gt 0 ] ;then
 			extra+=" WARN: CookieRecv: changed"
 		fi
 	fi
 
-	if [ ${stat_synrx_now_l} -gt ${expect_synrx} ]; then
+	if [ ${stat_synrx} -gt ${expect_synrx} ]; then
 		extra+=" WARN: SYNRX: expect ${expect_synrx},"
-		extra+=" got ${stat_synrx_now_l} (probably retransmissions)"
+		extra+=" got ${stat_synrx} (probably retransmissions)"
 	fi
-	if [ ${stat_ackrx_now_l} -gt ${expect_ackrx} ]; then
+	if [ ${stat_ackrx} -gt ${expect_ackrx} ]; then
 		extra+=" WARN: ACKRX: expect ${expect_ackrx},"
-		extra+=" got ${stat_ackrx_now_l} (probably retransmissions)"
+		extra+=" got ${stat_ackrx} (probably retransmissions)"
 	fi
 
 	if [ $retc -eq 0 ] && [ $rets -eq 0 ]; then
diff --git a/tools/testing/selftests/net/mptcp/mptcp_join.sh b/tools/testing/selftests/net/mptcp/mptcp_join.sh
index f0efbf985625..be61612f68fe 100755
--- a/tools/testing/selftests/net/mptcp/mptcp_join.sh
+++ b/tools/testing/selftests/net/mptcp/mptcp_join.sh
@@ -983,10 +983,8 @@ do_transfer()
 
 	cond_start_capture ${listener_ns}
 
-	NSTAT_HISTORY=/tmp/${listener_ns}.nstat ip netns exec ${listener_ns} \
-		nstat -n
-	NSTAT_HISTORY=/tmp/${connector_ns}.nstat ip netns exec ${connector_ns} \
-		nstat -n
+	mptcp_lib_nstat_init "${listener_ns}"
+	mptcp_lib_nstat_init "${connector_ns}"
 
 	local extra_args
 	if [ $speed = "fast" ]; then
@@ -1026,38 +1024,38 @@ do_transfer()
 	if [ "$test_linkfail" -gt 1 ];then
 		listener_in="${sinfail}"
 	fi
-	timeout ${timeout_test} \
-		ip netns exec ${listener_ns} \
-			./mptcp_connect -t ${timeout_poll} -l -p ${port} -s ${srv_proto} \
-				${extra_srv_args} "${bind_addr}" < "${listener_in}" > "${sout}" &
+	ip netns exec ${listener_ns} \
+		./mptcp_connect -t ${timeout_poll} -l -p ${port} -s ${srv_proto} \
+			${extra_srv_args} "${bind_addr}" < "${listener_in}" > "${sout}" &
 	local spid=$!
 
 	mptcp_lib_wait_local_port_listen "${listener_ns}" "${port}"
 
 	extra_cl_args="$extra_args $extra_cl_args"
 	if [ "$test_linkfail" -eq 0 ];then
-		timeout ${timeout_test} \
-			ip netns exec ${connector_ns} \
-				./mptcp_connect -t ${timeout_poll} -p $port -s ${cl_proto} \
-					$extra_cl_args $connect_addr < "$cin" > "$cout" &
+		ip netns exec ${connector_ns} \
+			./mptcp_connect -t ${timeout_poll} -p $port -s ${cl_proto} \
+				$extra_cl_args $connect_addr < "$cin" > "$cout" &
 	elif [ "$test_linkfail" -eq 1 ] || [ "$test_linkfail" -eq 2 ];then
 		connector_in="${cinsent}"
 		( cat "$cinfail" ; sleep 2; link_failure $listener_ns ; cat "$cinfail" ) | \
 			tee "$cinsent" | \
-			timeout ${timeout_test} \
 				ip netns exec ${connector_ns} \
 					./mptcp_connect -t ${timeout_poll} -p $port -s ${cl_proto} \
 						$extra_cl_args $connect_addr > "$cout" &
 	else
 		connector_in="${cinsent}"
 		tee "$cinsent" < "$cinfail" | \
-			timeout ${timeout_test} \
-				ip netns exec ${connector_ns} \
-					./mptcp_connect -t ${timeout_poll} -p $port -s ${cl_proto} \
-						$extra_cl_args $connect_addr > "$cout" &
+			ip netns exec ${connector_ns} \
+				./mptcp_connect -t ${timeout_poll} -p $port -s ${cl_proto} \
+					$extra_cl_args $connect_addr > "$cout" &
 	fi
 	local cpid=$!
 
+	mptcp_lib_wait_timeout "${timeout_test}" "${listener_ns}" \
+		"${connector_ns}" "${port}" "${cpid}" "${spid}" &
+	local timeout_pid=$!
+
 	pm_nl_set_endpoint $listener_ns $connector_ns $connect_addr
 	check_cestab $listener_ns $connector_ns
 
@@ -1066,17 +1064,20 @@ do_transfer()
 	wait $spid
 	local rets=$?
 
+	if kill -0 $timeout_pid; then
+		# Finished before the timeout: kill the background job
+		mptcp_lib_kill_group_wait $timeout_pid
+		timeout_pid=0
+	fi
+
 	cond_stop_capture
 
-	NSTAT_HISTORY=/tmp/${listener_ns}.nstat ip netns exec ${listener_ns} \
-		nstat | grep Tcp > /tmp/${listener_ns}.out
-	NSTAT_HISTORY=/tmp/${connector_ns}.nstat ip netns exec ${connector_ns} \
-		nstat | grep Tcp > /tmp/${connector_ns}.out
+	mptcp_lib_nstat_get "${listener_ns}"
+	mptcp_lib_nstat_get "${connector_ns}"
 
-	if [ ${rets} -ne 0 ] || [ ${retc} -ne 0 ]; then
+	if [ ${rets} -ne 0 ] || [ ${retc} -ne 0 ] || [ ${timeout_pid} -ne 0 ]; then
 		fail_test "client exit code $retc, server $rets"
-		mptcp_lib_pr_err_stats "${listener_ns}" "${connector_ns}" "${port}" \
-			"/tmp/${listener_ns}.out" "/tmp/${connector_ns}.out"
+		mptcp_lib_pr_err_stats "${listener_ns}" "${connector_ns}" "${port}"
 		return 1
 	fi
 
@@ -1151,12 +1152,20 @@ run_tests()
 	do_transfer ${listener_ns} ${connector_ns} MPTCP MPTCP ${connect_addr}
 }
 
+_dump_stats()
+{
+	local ns="${1}"
+	local side="${2}"
+
+	mptcp_lib_print_err "${side} ns stats (${ns2})"
+	mptcp_lib_pr_nstat "${ns}"
+	echo
+}
+
 dump_stats()
 {
-	echo Server ns stats
-	ip netns exec $ns1 nstat -as | grep Tcp
-	echo Client ns stats
-	ip netns exec $ns2 nstat -as | grep Tcp
+	_dump_stats "${ns1}" "Server"
+	_dump_stats "${ns2}" "Client"
 }
 
 chk_csum_nr()
diff --git a/tools/testing/selftests/net/mptcp/mptcp_lib.sh b/tools/testing/selftests/net/mptcp/mptcp_lib.sh
index f4388900016a..5fea7e7df628 100644
--- a/tools/testing/selftests/net/mptcp/mptcp_lib.sh
+++ b/tools/testing/selftests/net/mptcp/mptcp_lib.sh
@@ -106,23 +106,32 @@ mptcp_lib_pr_info() {
 	mptcp_lib_print_info "INFO: ${*}"
 }
 
-# $1-2: listener/connector ns ; $3 port ; $4-5 listener/connector stat file
+mptcp_lib_pr_nstat() {
+	local ns="${1}"
+	local hist="/tmp/${ns}.out"
+
+	if [ -f "${hist}" ]; then
+		awk '$2 != 0 { print "  "$0 }' "${hist}"
+	else
+		ip netns exec "${ns}" nstat -as | grep Tcp
+	fi
+}
+
+# $1-2: listener/connector ns ; $3 port
 mptcp_lib_pr_err_stats() {
 	local lns="${1}"
 	local cns="${2}"
 	local port="${3}"
-	local lstat="${4}"
-	local cstat="${5}"
 
 	echo -en "${MPTCP_LIB_COLOR_RED}"
 	{
 		printf "\nnetns %s (listener) socket stat for %d:\n" "${lns}" "${port}"
 		ip netns exec "${lns}" ss -Menitam -o "sport = :${port}"
-		cat "${lstat}"
+		mptcp_lib_pr_nstat "${lns}"
 
 		printf "\nnetns %s (connector) socket stat for %d:\n" "${cns}" "${port}"
 		ip netns exec "${cns}" ss -Menitam -o "dport = :${port}"
-		[ "${lstat}" != "${cstat}" ] && cat "${cstat}"
+		[ "${lns}" != "${cns}" ] && mptcp_lib_pr_nstat "${cns}"
 	} 1>&2
 	echo -en "${MPTCP_LIB_COLOR_RESET}"
 }
@@ -341,6 +350,19 @@ mptcp_lib_evts_get_info() {
 		mptcp_lib_get_info_value "${1}" "^type:${3:-1},"
 }
 
+mptcp_lib_wait_timeout() {
+	local timeout_test="${1}"
+	local listener_ns="${2}"
+	local connector_ns="${3}"
+	local port="${4}"
+	shift 4 # rest are PIDs
+
+	sleep "${timeout_test}"
+	mptcp_lib_print_err "timeout"
+	mptcp_lib_pr_err_stats "${listener_ns}" "${connector_ns}" "${port}"
+	kill "${@}" 2>/dev/null
+}
+
 # $1: PID
 mptcp_lib_kill_wait() {
 	[ "${1}" -eq 0 ] && return 0
@@ -376,14 +398,36 @@ mptcp_lib_is_v6() {
 	[ -z "${1##*:*}" ]
 }
 
+mptcp_lib_nstat_init() {
+	local ns="${1}"
+
+	rm -f "/tmp/${ns}."{nstat,out}
+	NSTAT_HISTORY="/tmp/${ns}.nstat" ip netns exec "${ns}" nstat -n
+}
+
+mptcp_lib_nstat_get() {
+	local ns="${1}"
+
+	# filter out non-*TCP stats, and the rate (last column)
+	NSTAT_HISTORY="/tmp/${ns}.nstat" ip netns exec "${ns}" nstat -sz |
+		grep -o ".*Tcp\S\+\s\+[0-9]\+" > "/tmp/${ns}.out"
+}
+
 # $1: ns, $2: MIB counter
+# Get the counter from the history (mptcp_lib_nstat_{init,get}()) if available.
+# If not, get the counter from nstat ignoring any history.
 mptcp_lib_get_counter() {
 	local ns="${1}"
 	local counter="${2}"
+	local hist="/tmp/${ns}.out"
 	local count
 
-	count=$(ip netns exec "${ns}" nstat -asz "${counter}" |
-		awk 'NR==1 {next} {print $2}')
+	if [[ -s "${hist}" && "${counter}" == *"Tcp"* ]]; then
+		count=$(awk "/^${counter} / {print \$2; exit}" "${hist}")
+	else
+		count=$(ip netns exec "${ns}" nstat -asz "${counter}" |
+			awk 'NR==1 {next} {print $2}')
+	fi
 	if [ -z "${count}" ]; then
 		mptcp_lib_fail_if_expected_feature "${counter} counter"
 		return 1
diff --git a/tools/testing/selftests/net/mptcp/mptcp_sockopt.sh b/tools/testing/selftests/net/mptcp/mptcp_sockopt.sh
index f01989be6e9b..ab8bce06b262 100755
--- a/tools/testing/selftests/net/mptcp/mptcp_sockopt.sh
+++ b/tools/testing/selftests/net/mptcp/mptcp_sockopt.sh
@@ -169,41 +169,44 @@ do_transfer()
 		cmsg+=",TCPINQ"
 	fi
 
-	NSTAT_HISTORY=/tmp/${listener_ns}.nstat ip netns exec ${listener_ns} \
-		nstat -n
-	NSTAT_HISTORY=/tmp/${connector_ns}.nstat ip netns exec ${connector_ns} \
-		nstat -n
-
-	timeout ${timeout_test} \
-		ip netns exec ${listener_ns} \
-			$mptcp_connect -t ${timeout_poll} -l -M 1 -p $port -s ${srv_proto} -c "${cmsg}" \
-				${local_addr} < "$sin" > "$sout" &
+	mptcp_lib_nstat_init "${listener_ns}"
+	mptcp_lib_nstat_init "${connector_ns}"
+
+	ip netns exec ${listener_ns} \
+		$mptcp_connect -t ${timeout_poll} -l -M 1 -p $port -s ${srv_proto} -c "${cmsg}" \
+			${local_addr} < "$sin" > "$sout" &
 	local spid=$!
 
-	sleep 1
+	mptcp_lib_wait_local_port_listen "${listener_ns}" "${port}"
 
-	timeout ${timeout_test} \
-		ip netns exec ${connector_ns} \
-			$mptcp_connect -t ${timeout_poll} -M 2 -p $port -s ${cl_proto} -c "${cmsg}" \
-				$connect_addr < "$cin" > "$cout" &
+	ip netns exec ${connector_ns} \
+		$mptcp_connect -t ${timeout_poll} -M 2 -p $port -s ${cl_proto} -c "${cmsg}" \
+			$connect_addr < "$cin" > "$cout" &
 
 	local cpid=$!
 
+	mptcp_lib_wait_timeout "${timeout_test}" "${listener_ns}" \
+		"${connector_ns}" "${port}" "${cpid}" "${spid}" &
+	local timeout_pid=$!
+
 	wait $cpid
 	local retc=$?
 	wait $spid
 	local rets=$?
 
-	NSTAT_HISTORY=/tmp/${listener_ns}.nstat ip netns exec ${listener_ns} \
-		nstat | grep Tcp > /tmp/${listener_ns}.out
-	NSTAT_HISTORY=/tmp/${connector_ns}.nstat ip netns exec ${connector_ns} \
-		nstat | grep Tcp > /tmp/${connector_ns}.out
+	if kill -0 $timeout_pid; then
+		# Finished before the timeout: kill the background job
+		mptcp_lib_kill_group_wait $timeout_pid
+		timeout_pid=0
+	fi
+
+	mptcp_lib_nstat_get "${listener_ns}"
+	mptcp_lib_nstat_get "${connector_ns}"
 
 	print_title "Transfer ${ip:2}"
-	if [ ${rets} -ne 0 ] || [ ${retc} -ne 0 ]; then
+	if [ ${rets} -ne 0 ] || [ ${retc} -ne 0 ] || [ ${timeout_pid} -ne 0 ]; then
 		mptcp_lib_pr_fail "client exit code $retc, server $rets"
-		mptcp_lib_pr_err_stats "${listener_ns}" "${connector_ns}" "${port}" \
-			"/tmp/${listener_ns}.out" "/tmp/${connector_ns}.out"
+		mptcp_lib_pr_err_stats "${listener_ns}" "${connector_ns}" "${port}"
 
 		mptcp_lib_result_fail "transfer ${ip}"
 
diff --git a/tools/testing/selftests/net/mptcp/simult_flows.sh b/tools/testing/selftests/net/mptcp/simult_flows.sh
index 1903e8e84a31..806aaa7d2d61 100755
--- a/tools/testing/selftests/net/mptcp/simult_flows.sh
+++ b/tools/testing/selftests/net/mptcp/simult_flows.sh
@@ -155,48 +155,53 @@ do_transfer()
 		sleep 1
 	fi
 
-	NSTAT_HISTORY=/tmp/${ns3}.nstat ip netns exec ${ns3} \
-		nstat -n
-	NSTAT_HISTORY=/tmp/${ns1}.nstat ip netns exec ${ns1} \
-		nstat -n
-
-	timeout ${timeout_test} \
-		ip netns exec ${ns3} \
-			./mptcp_connect -jt ${timeout_poll} -l -p $port -T $max_time \
-				0.0.0.0 < "$sin" > "$sout" &
+	mptcp_lib_nstat_init "${ns3}"
+	mptcp_lib_nstat_init "${ns1}"
+
+	ip netns exec ${ns3} \
+		./mptcp_connect -jt ${timeout_poll} -l -p $port -T $max_time \
+			0.0.0.0 < "$sin" > "$sout" &
 	local spid=$!
 
 	mptcp_lib_wait_local_port_listen "${ns3}" "${port}"
 
-	timeout ${timeout_test} \
-		ip netns exec ${ns1} \
-			./mptcp_connect -jt ${timeout_poll} -p $port -T $max_time \
-				10.0.3.3 < "$cin" > "$cout" &
+	ip netns exec ${ns1} \
+		./mptcp_connect -jt ${timeout_poll} -p $port -T $max_time \
+			10.0.3.3 < "$cin" > "$cout" &
 	local cpid=$!
 
+	mptcp_lib_wait_timeout "${timeout_test}" "${ns3}" "${ns1}" "${port}" \
+		"${cpid}" "${spid}" &
+	local timeout_pid=$!
+
 	wait $cpid
 	local retc=$?
 	wait $spid
 	local rets=$?
 
+	if kill -0 $timeout_pid; then
+		# Finished before the timeout: kill the background job
+		mptcp_lib_kill_group_wait $timeout_pid
+		timeout_pid=0
+	fi
+
 	if $capture; then
 		sleep 1
 		kill ${cappid_listener}
 		kill ${cappid_connector}
 	fi
 
-	NSTAT_HISTORY=/tmp/${ns3}.nstat ip netns exec ${ns3} \
-		nstat | grep Tcp > /tmp/${ns3}.out
-	NSTAT_HISTORY=/tmp/${ns1}.nstat ip netns exec ${ns1} \
-		nstat | grep Tcp > /tmp/${ns1}.out
+	mptcp_lib_nstat_get "${ns3}"
+	mptcp_lib_nstat_get "${ns1}"
 
 	cmp $sin $cout > /dev/null 2>&1
 	local cmps=$?
 	cmp $cin $sout > /dev/null 2>&1
 	local cmpc=$?
 
-	if [ $retc -eq 0 ] && [ $rets -eq 0 ] && \
-	   [ $cmpc -eq 0 ] && [ $cmps -eq 0 ]; then
+	if [ $retc -eq 0 ] && [ $rets -eq 0 ] &&
+	   [ $cmpc -eq 0 ] && [ $cmps -eq 0 ] &&
+	   [ $timeout_pid -eq 0 ]; then
 		printf "%-16s" " max $max_time "
 		mptcp_lib_pr_ok
 		cat "$capout"
@@ -204,8 +209,7 @@ do_transfer()
 	fi
 
 	mptcp_lib_pr_fail "client exit code $retc, server $rets"
-	mptcp_lib_pr_err_stats "${ns3}" "${ns1}" "${port}" \
-		"/tmp/${ns3}.out" "/tmp/${ns1}.out"
+	mptcp_lib_pr_err_stats "${ns3}" "${ns1}" "${port}"
 	ls -l $sin $cout
 	ls -l $cin $sout
 
diff --git a/tools/testing/selftests/net/mptcp/userspace_pm.sh b/tools/testing/selftests/net/mptcp/userspace_pm.sh
index 87323942cb8a..e9ae1806ab07 100755
--- a/tools/testing/selftests/net/mptcp/userspace_pm.sh
+++ b/tools/testing/selftests/net/mptcp/userspace_pm.sh
@@ -211,7 +211,8 @@ make_connection()
 	ip netns exec "$ns1" \
 	   ./mptcp_connect -s MPTCP -w 300 -p $app_port -l $listen_addr > /dev/null 2>&1 &
 	local server_pid=$!
-	sleep 0.5
+
+	mptcp_lib_wait_local_port_listen "${ns1}" "${port}"
 
 	# Run the client, transfer $file and stay connected to the server
 	# to conduct tests