selftests: mptcp: add mptcp_lib_wait_local_port_listen

To avoid duplicated code in different MPTCP selftests, we can add
and use helpers defined in mptcp_lib.sh.

wait_local_port_listen() helper is defined in diag.sh, mptcp_connect.sh,
mptcp_join.sh and simult_flows.sh, export it into mptcp_lib.sh and
rename it with mptcp_lib_ prefix. Use this new helper in all these
scripts.

Note: We only have IPv4 connections in this helper, not looking at IPv6
(tcp6) but that's OK because we only have IPv4 connections here in diag.sh.

Reviewed-by: Matthieu Baerts <matttbe@kernel.org>
Signed-off-by: Geliang Tang <geliang.tang@suse.com>
Signed-off-by: Mat Martineau <martineau@kernel.org>
Link: https://lore.kernel.org/r/20231128-send-net-next-2023107-v4-15-8d6b94150f6b@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

tools/testing/selftests/net/mptcp/diag.sh

@@ -182,23 +182,6 @@ chk_msk_inuse()
 	__chk_nr get_msk_inuse $expected "$msg" 0
 }
 
-# $1: ns, $2: port
-wait_local_port_listen()
-{
-	local listener_ns="${1}"
-	local port="${2}"
-
-	local port_hex i
-
-	port_hex="$(printf "%04X" "${port}")"
-	for i in $(seq 10); do
-		ip netns exec "${listener_ns}" cat /proc/net/tcp | \
-			awk "BEGIN {rc=1} {if (\$2 ~ /:${port_hex}\$/ && \$4 ~ /0A/) {rc=0; exit}} END {exit rc}" &&
-			break
-		sleep 0.1
-	done
-}
-
 wait_connected()
 {
 	local listener_ns="${1}"
@@ -222,7 +205,7 @@ echo "a" | \
 		ip netns exec $ns \
 			./mptcp_connect -p 10000 -l -t ${timeout_poll} -w 20 \
 				0.0.0.0 >/dev/null &
-wait_local_port_listen $ns 10000
+mptcp_lib_wait_local_port_listen $ns 10000
 chk_msk_nr 0 "no msk on netns creation"
 chk_msk_listen 10000
 
@@ -245,7 +228,7 @@ echo "a" | \
 		ip netns exec $ns \
 			./mptcp_connect -p 10001 -l -s TCP -t ${timeout_poll} -w 20 \
 				0.0.0.0 >/dev/null &
-wait_local_port_listen $ns 10001
+mptcp_lib_wait_local_port_listen $ns 10001
 echo "b" | \
 	timeout ${timeout_test} \
 		ip netns exec $ns \
@@ -266,7 +249,7 @@ for I in `seq 1 $NR_CLIENTS`; do
 				./mptcp_connect -p $((I+10001)) -l -w 20 \
 					-t ${timeout_poll} 0.0.0.0 >/dev/null &
 done
-wait_local_port_listen $ns $((NR_CLIENTS + 10001))
+mptcp_lib_wait_local_port_listen $ns $((NR_CLIENTS + 10001))
 
 for I in `seq 1 $NR_CLIENTS`; do
 	echo "b" | \

tools/testing/selftests/net/mptcp/mptcp_connect.sh

@@ -310,23 +310,6 @@ do_ping()
 	return 0
 }
 
-# $1: ns, $2: port
-wait_local_port_listen()
-{
-	local listener_ns="${1}"
-	local port="${2}"
-
-	local port_hex i
-
-	port_hex="$(printf "%04X" "${port}")"
-	for i in $(seq 10); do
-		ip netns exec "${listener_ns}" cat /proc/net/tcp* | \
-			awk "BEGIN {rc=1} {if (\$2 ~ /:${port_hex}\$/ && \$4 ~ /0A/) {rc=0; exit}} END {exit rc}" &&
-			break
-		sleep 0.1
-	done
-}
-
 do_transfer()
 {
 	local listener_ns="$1"
@@ -408,7 +391,7 @@ do_transfer()
 				$extra_args $local_addr < "$sin" > "$sout" &
 	local spid=$!
 
-	wait_local_port_listen "${listener_ns}" "${port}"
+	mptcp_lib_wait_local_port_listen "${listener_ns}" "${port}"
 
 	local start
 	start=$(date +%s%3N)

tools/testing/selftests/net/mptcp/mptcp_join.sh

@@ -580,24 +580,6 @@ link_failure()
 	done
 }
 
-# $1: ns, $2: port
-wait_local_port_listen()
-{
-	local listener_ns="${1}"
-	local port="${2}"
-
-	local port_hex
-	port_hex="$(printf "%04X" "${port}")"
-
-	local i
-	for i in $(seq 10); do
-		ip netns exec "${listener_ns}" cat /proc/net/tcp* | \
-			awk "BEGIN {rc=1} {if (\$2 ~ /:${port_hex}\$/ && \$4 ~ /0A/) {rc=0; exit}} END {exit rc}" &&
-			break
-		sleep 0.1
-	done
-}
-
 rm_addr_count()
 {
 	mptcp_lib_get_counter "${1}" "MPTcpExtRmAddr"
@@ -1082,7 +1064,7 @@ do_transfer()
 	fi
 	local spid=$!
 
-	wait_local_port_listen "${listener_ns}" "${port}"
+	mptcp_lib_wait_local_port_listen "${listener_ns}" "${port}"
 
 	extra_cl_args="$extra_args $extra_cl_args"
 	if [ "$test_linkfail" -eq 0 ];then

tools/testing/selftests/net/mptcp/mptcp_lib.sh

@@ -280,3 +280,21 @@ mptcp_lib_check_transfer() {
 
 	return 0
 }
+
+# $1: ns, $2: port
+mptcp_lib_wait_local_port_listen() {
+	local listener_ns="${1}"
+	local port="${2}"
+
+	local port_hex
+	port_hex="$(printf "%04X" "${port}")"
+
+	local _
+	for _ in $(seq 10); do
+		ip netns exec "${listener_ns}" cat /proc/net/tcp* | \
+			awk "BEGIN {rc=1} {if (\$2 ~ /:${port_hex}\$/ && \$4 ~ /0A/) \
+			     {rc=0; exit}} END {exit rc}" &&
+			break
+		sleep 0.1
+	done
+}

tools/testing/selftests/net/mptcp/simult_flows.sh

@@ -123,23 +123,6 @@ setup()
 	grep -q ' kmemleak_init$\| lockdep_init$\| kasan_init$\| prove_locking$' /proc/kallsyms && slack=$((slack+550))
 }
 
-# $1: ns, $2: port
-wait_local_port_listen()
-{
-	local listener_ns="${1}"
-	local port="${2}"
-
-	local port_hex i
-
-	port_hex="$(printf "%04X" "${port}")"
-	for i in $(seq 10); do
-		ip netns exec "${listener_ns}" cat /proc/net/tcp* | \
-			awk "BEGIN {rc=1} {if (\$2 ~ /:${port_hex}\$/ && \$4 ~ /0A/) {rc=0; exit}} END {exit rc}" &&
-			break
-		sleep 0.1
-	done
-}
-
 do_transfer()
 {
 	local cin=$1
@@ -179,7 +162,7 @@ do_transfer()
 				0.0.0.0 < "$sin" > "$sout" &
 	local spid=$!
 
-	wait_local_port_listen "${ns3}" "${port}"
+	mptcp_lib_wait_local_port_listen "${ns3}" "${port}"
 
 	timeout ${timeout_test} \
 		ip netns exec ${ns1} \