selftests: mptcp: add the MP_RST mibs check

This patch added a new function chk_rst_nr() to check the numbers
of the MP_RST sending and receiving mibs.

Showed in the output whether the inverted namespaces check order is used.
Since if we pass -Cz to mptcp_join.sh, the MP_RST information is showed
twice.
Signed-off-by: Geliang Tang <geliang.tang@suse.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

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

@@ -824,6 +824,50 @@ chk_fclose_nr()
 	[ "${dump_stats}" = 1 ] && dump_stats
 }
 
+chk_rst_nr()
+{
+	local rst_tx=$1
+	local rst_rx=$2
+	local ns_invert=${3:-""}
+	local count
+	local dump_stats
+	local ns_tx=$ns1
+	local ns_rx=$ns2
+	local extra_msg=""
+
+	if [[ $ns_invert = "invert" ]]; then
+		ns_tx=$ns2
+		ns_rx=$ns1
+		extra_msg="   invert"
+	fi
+
+	printf "%-${nr_blank}s %s" " " "rtx"
+	count=$(ip netns exec $ns_tx nstat -as | grep MPTcpExtMPRstTx | awk '{print $2}')
+	[ -z "$count" ] && count=0
+	if [ "$count" != "$rst_tx" ]; then
+		echo "[fail] got $count MP_RST[s] TX expected $rst_tx"
+		ret=1
+		dump_stats=1
+	else
+		echo -n "[ ok ]"
+	fi
+
+	echo -n " - rstrx "
+	count=$(ip netns exec $ns_rx nstat -as | grep MPTcpExtMPRstRx | awk '{print $2}')
+	[ -z "$count" ] && count=0
+	if [ "$count" != "$rst_rx" ]; then
+		echo "[fail] got $count MP_RST[s] RX expected $rst_rx"
+		ret=1
+		dump_stats=1
+	else
+		echo -n "[ ok ]"
+	fi
+
+	[ "${dump_stats}" = 1 ] && dump_stats
+
+	echo "$extra_msg"
+}
+
 chk_join_nr()
 {
 	local msg="$1"
@@ -878,6 +922,7 @@ chk_join_nr()
 	if [ $checksum -eq 1 ]; then
 		chk_csum_nr
 		chk_fail_nr 0 0
+		chk_rst_nr 0 0
 	fi
 }