diff --git a/tools/testing/selftests/net/mptcp/mptcp_sockopt.sh b/tools/testing/selftests/net/mptcp/mptcp_sockopt.sh
index f74b237bcb32..1b70c0a304ce 100755
--- a/tools/testing/selftests/net/mptcp/mptcp_sockopt.sh
+++ b/tools/testing/selftests/net/mptcp/mptcp_sockopt.sh
@@ -22,6 +22,7 @@ add_mark_rules()
 	local ns=$1
 	local m=$2
 
+	local t
 	for t in iptables ip6tables; do
 		# just to debug: check we have multiple subflows connection requests
 		ip netns exec $ns $t -A OUTPUT -p tcp --syn -m mark --mark $m -j ACCEPT
@@ -36,6 +37,7 @@ add_mark_rules()
 
 init()
 {
+	local netns
 	for netns in "$ns1" "$ns2" "$ns_sbox";do
 		ip netns add $netns || exit $ksft_skip
 		ip -net $netns link set lo up
@@ -44,6 +46,7 @@ init()
 		ip netns exec $netns sysctl -q net.ipv4.conf.default.rp_filter=0
 	done
 
+	local i
 	for i in `seq 1 4`; do
 		ip link add ns1eth$i netns "$ns1" type veth peer name ns2eth$i netns "$ns2"
 		ip -net "$ns1" addr add 10.0.$i.1/24 dev ns1eth$i
@@ -73,6 +76,7 @@ init()
 
 cleanup()
 {
+	local netns
 	for netns in "$ns1" "$ns2" "$ns_sbox"; do
 		ip netns del $netns
 	done
@@ -103,15 +107,17 @@ check_mark()
 	local ns=$1
 	local af=$2
 
-	tables=iptables
+	local tables=iptables
 
 	if [ $af -eq 6 ];then
 		tables=ip6tables
 	fi
 
+	local counters values
 	counters=$(ip netns exec $ns $tables -v -L OUTPUT | grep DROP)
 	values=${counters%DROP*}
 
+	local v
 	for v in $values; do
 		if [ $v -ne 0 ]; then
 			echo "FAIL: got $tables $values in ns $ns , not 0 - not all expected packets marked" 1>&2
@@ -131,9 +137,9 @@ print_file_err()
 
 check_transfer()
 {
-	in=$1
-	out=$2
-	what=$3
+	local in=$1
+	local out=$2
+	local what=$3
 
 	cmp "$in" "$out" > /dev/null 2>&1
 	if [ $? -ne 0 ] ;then
@@ -156,18 +162,18 @@ is_v6()
 
 do_transfer()
 {
-	listener_ns="$1"
-	connector_ns="$2"
-	cl_proto="$3"
-	srv_proto="$4"
-	connect_addr="$5"
+	local listener_ns="$1"
+	local connector_ns="$2"
+	local cl_proto="$3"
+	local srv_proto="$4"
+	local connect_addr="$5"
 
-	port=12001
+	local port=12001
 
 	:> "$cout"
 	:> "$sout"
 
-	mptcp_connect="./mptcp_connect -r 20"
+	local mptcp_connect="./mptcp_connect -r 20"
 
 	local local_addr
 	if is_v6 "${connect_addr}"; then
@@ -180,7 +186,7 @@ do_transfer()
 		ip netns exec ${listener_ns} \
 			$mptcp_connect -t ${timeout_poll} -l -M 1 -p $port -s ${srv_proto} -c TIMESTAMPNS,TCPINQ \
 				${local_addr} < "$sin" > "$sout" &
-	spid=$!
+	local spid=$!
 
 	sleep 1
 
@@ -189,12 +195,12 @@ do_transfer()
 			$mptcp_connect -t ${timeout_poll} -M 2 -p $port -s ${cl_proto} -c TIMESTAMPNS,TCPINQ \
 				$connect_addr < "$cin" > "$cout" &
 
-	cpid=$!
+	local cpid=$!
 
 	wait $cpid
-	retc=$?
+	local retc=$?
 	wait $spid
-	rets=$?
+	local rets=$?
 
 	if [ ${rets} -ne 0 ] || [ ${retc} -ne 0 ]; then
 		echo " client exit code $retc, server $rets" 1>&2
@@ -229,9 +235,9 @@ do_transfer()
 
 make_file()
 {
-	name=$1
-	who=$2
-	size=$3
+	local name=$1
+	local who=$2
+	local size=$3
 
 	dd if=/dev/urandom of="$name" bs=1024 count=$size 2> /dev/null
 	echo -e "\nMPTCP_TEST_FILE_END_MARKER" >> "$name"
@@ -264,9 +270,9 @@ do_mptcp_sockopt_tests()
 
 run_tests()
 {
-	listener_ns="$1"
-	connector_ns="$2"
-	connect_addr="$3"
+	local listener_ns="$1"
+	local connector_ns="$2"
+	local connect_addr="$3"
 	local lret=0
 
 	do_transfer ${listener_ns} ${connector_ns} MPTCP MPTCP ${connect_addr}
@@ -282,7 +288,7 @@ run_tests()
 do_tcpinq_test()
 {
 	ip netns exec "$ns_sbox" ./mptcp_inq "$@"
-	lret=$?
+	local lret=$?
 	if [ $lret -ne 0 ];then
 		ret=$lret
 		echo "FAIL: mptcp_inq $@" 1>&2
@@ -297,6 +303,7 @@ do_tcpinq_tests()
 {
 	local lret=0
 
+	local args
 	for args in "-t tcp" "-r tcp"; do
 		do_tcpinq_test $args
 		lret=$?