Merge branch 'selftests-net-more-pmtu-sh-fixes'

Paolo Abeni says:

====================
selftests: net: more pmtu.sh fixes

The mentioned test is still flaky, unusally enough in 'fast'
environments.

Patch 2/2 [try to] address the existing issues, while patch 1/2
introduces more strict tests for the existing net helpers, to hopefully
prevent future pain.
====================

Link: https://lore.kernel.org/r/cover.1707731086.git.pabeni@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

tools/testing/selftests/net/net_helper.sh

@@ -8,13 +8,16 @@ wait_local_port_listen()
 	local listener_ns="${1}"
 	local port="${2}"
 	local protocol="${3}"
-	local port_hex
+	local pattern
 	local i
 
-	port_hex="$(printf "%04X" "${port}")"
+	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}" cat /proc/net/"${protocol}"* | \
-		   grep -q "${port_hex}"; then
+		if ip netns exec "${listener_ns}" awk '{print $2" "$4}' \
+		   /proc/net/"${protocol}"* | grep -q "${pattern}"; then
 			break
 		fi
 		sleep 0.1

tools/testing/selftests/net/pmtu.sh

@@ -1336,16 +1336,16 @@ test_pmtu_ipvX_over_bridged_vxlanY_or_geneveY_exception() {
 		else
 			TCPDST="TCP:[${dst}]:50000"
 		fi
-		${ns_b} socat -T 3 -u -6 TCP-LISTEN:50000 STDOUT > $tmpoutfile &
+		${ns_b} socat -T 3 -u -6 TCP-LISTEN:50000,reuseaddr STDOUT > $tmpoutfile &
 		local socat_pid=$!
 
 		wait_local_port_listen ${NS_B} 50000 tcp
 
 		dd if=/dev/zero status=none bs=1M count=1 | ${target} socat -T 3 -u STDIN $TCPDST,connect-timeout=3
 
+		wait ${socat_pid}
 		size=$(du -sb $tmpoutfile)
 		size=${size%%/tmp/*}
-		wait ${socat_pid}
 
 		[ $size -ne 1048576 ] && err "File size $size mismatches exepcted value in locally bridged vxlan test" && return 1
 	done