selftests: mptcp: add mptcp_info tests

This patch adds the mptcp_info fields tests in endpoint_tests(). Add a
new function chk_mptcp_info() to check the given number of the given
mptcp_info field.

Closes: multipath-tcp/mptcp_net-next#330
Signed-off-by: Geliang Tang <geliang.tang@suse.com>

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

@@ -1719,6 +1719,46 @@ chk_subflow_nr()
 	fi
 }
 
+chk_mptcp_info()
+{
+	local nr_info=$1
+	local info
+	local cnt1
+	local cnt2
+	local dump_stats
+
+	if [[ $nr_info = "subflows_"* ]]; then
+		info="subflows"
+		nr_info=${nr_info:9}
+	else
+		echo "[fail] $nr_info"
+		fail_test
+		dump_stats=1
+	fi
+
+	printf "%-${nr_blank}s %-30s" " " "mptcp_info $info=$nr_info"
+
+	cnt1=$(ss -N $ns1 -inmHM | grep "$info:" |
+		sed -n 's/.*\('"$info"':\)\([[:digit:]]*\).*$/\2/p;q')
+	[ -z $cnt1 ] && cnt1=0
+	cnt2=$(ss -N $ns2 -inmHM | grep "$info:" |
+		sed -n 's/.*\('"$info"':\)\([[:digit:]]*\).*$/\2/p;q')
+	[ -z $cnt2 ] && cnt2=0
+	if [ $cnt1 != $nr_info -o $cnt2 != $nr_info ]; then
+		echo "[fail] got $cnt1:$cnt2 $info expected $nr_info"
+		fail_test
+		dump_stats=1
+	else
+		echo "[ ok ]"
+	fi
+
+	if [ "$dump_stats" = 1 ]; then
+		ss -N $ns1 -inmHM
+		ss -N $ns2 -inmHM
+		dump_stats
+	fi
+}
+
 chk_link_usage()
 {
 	local ns=$1
@@ -3118,13 +3158,16 @@ endpoint_tests()
 		run_tests $ns1 $ns2 10.0.1.1 4 0 0 speed_20 2>/dev/null &
 
 		wait_mpj $ns2
+		chk_mptcp_info subflows_1
 		pm_nl_del_endpoint $ns2 2 10.0.2.2
 		sleep 0.5
 		chk_subflow_nr needtitle "after delete" 1
+		chk_mptcp_info subflows_0
 
 		pm_nl_add_endpoint $ns2 10.0.2.2 dev ns2eth2 flags subflow
 		wait_mpj $ns2
 		chk_subflow_nr "" "after re-add" 2
+		chk_mptcp_info subflows_1
 		kill_tests_wait
 	fi
 }