[PATCH v2 3/4] test: shell: Add wait_local_port_listen() helper to lib.sh

[Yi Chen <yiche@xxxxxxxxxx>]

Introduce a new helper function wait_local_port_listen() in helpers/lib.sh.
Update the flowtables and nat_ftp test cases to use this helper.

Signed-off-by: Yi Chen <yiche@xxxxxxxxxx>
---
 tests/shell/helpers/lib.sh                  | 21 +++++++++++++++++++++
 tests/shell/testcases/packetpath/flowtables |  3 ++-
 tests/shell/testcases/packetpath/nat_ftp    |  6 ++++--
 3 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/tests/shell/helpers/lib.sh b/tests/shell/helpers/lib.sh
index d2d20984..ce27aac3 100755
--- a/tests/shell/helpers/lib.sh
+++ b/tests/shell/helpers/lib.sh
@@ -28,3 +28,24 @@ assert_fail()
 		echo "PASS: ${@}"
 	fi
 }
+
+wait_local_port_listen()
+{
+	local listener_ns="${1}"
+	local port="${2}"
+	local protocol="${3}"
+	local pattern
+	local i
+
+	pattern=":$(printf "%04X" "${port}") "
+
+	# for tcp protocol additionally check the socket state
+	[ ${protocol} = "tcp" ] && pattern="${pattern}0A"
+	for i in $(seq 10); do
+		if ip netns exec "${listener_ns}" awk '{print $2" "$4}' \
+		   /proc/net/"${protocol}"* | grep -q "${pattern}"; then
+			break
+		fi
+		sleep 0.1
+	done
+}
diff --git a/tests/shell/testcases/packetpath/flowtables b/tests/shell/testcases/packetpath/flowtables
index f3580a5f..dbe470a8 100755
--- a/tests/shell/testcases/packetpath/flowtables
+++ b/tests/shell/testcases/packetpath/flowtables
@@ -83,7 +83,8 @@ assert_pass "set net.netfilter.nf_conntrack_tcp_timeout_established=86400"
 
 # A trick to control the timing to send a packet
 ip netns exec $S socat TCP6-LISTEN:10001 GOPEN:/tmp/socat-$rnd,ignoreeof &
-sleep 1
+wait_local_port_listen $S 10001 tcp
+
 ip netns exec $C socat -b 2048 PIPE:/tmp/pipefile-$rnd 'TCP:[2001:db8:ffff:22::1]:10001' &
 sleep 1
 ip netns exec $C echo "send sth" >> /tmp/pipefile-$rnd        ; assert_pass "send a packet"
diff --git a/tests/shell/testcases/packetpath/nat_ftp b/tests/shell/testcases/packetpath/nat_ftp
index 37ef14a3..3ba4029d 100755
--- a/tests/shell/testcases/packetpath/nat_ftp
+++ b/tests/shell/testcases/packetpath/nat_ftp
@@ -132,7 +132,8 @@ pam_service_name=vsftpd
 background=YES
 EOF
 ip netns exec $S vsftpd ${FTPCONF}
-sleep 1
+wait_local_port_listen $S 21 tcp
+
 ip netns exec $S ss -6ltnp | grep -q '*:21'
 assert_pass "start vsftpd server"
 
@@ -141,7 +142,7 @@ assert_pass "start vsftpd server"
 reload_ruleset
 ip netns exec $S tcpdump -q --immediate-mode -Ui s_r -w ${PCAP} 2> /dev/null &
 pid=$!
-sleep 1
+sleep 0.5
 ip netns exec $C curl --no-progress-meter --connect-timeout 5 ftp://[${ip_rc}]:2121/$(basename $INFILE) -o $OUTFILE
 assert_pass "curl ftp passive mode "
 
@@ -158,6 +159,7 @@ reload_ruleset
 
 ip netns exec $S tcpdump -q --immediate-mode -Ui s_r -w ${PCAP} 2> /dev/null &
 pid=$!
+sleep 0.5
 ip netns exec $C curl --no-progress-meter -P - --connect-timeout 5 ftp://[${ip_rc}]:2121/$(basename $INFILE) -o $OUTFILE
 assert_pass "curl ftp active mode "
 
-- 
2.49.0