selftests: mptcp: diag: check CURRESTAB counters

This patch adds a new helper chk_msk_cestab() to check the current
established connections counter MIB_CURRESTAB in diag.sh. Invoke it
to check the counter during the connection after every chk_msk_inuse().
Signed-off-by: Geliang Tang <geliang.tang@linux.dev>
Reviewed-by: Matthieu Baerts <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts <matttbe@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -56,7 +56,7 @@ __chk_nr()
 	local command="$1"
 	local expected=$2
 	local msg="$3"
-	local skip="${4:-SKIP}"
+	local skip="${4-SKIP}"
 	local nr
 
 	nr=$(eval $command)
@@ -182,6 +182,15 @@ chk_msk_inuse()
 	__chk_nr get_msk_inuse $expected "$msg" 0
 }
 
+# $1: cestab nr
+chk_msk_cestab()
+{
+	local cestab=$1
+
+	__chk_nr "mptcp_lib_get_counter ${ns} MPTcpExtMPCurrEstab" \
+		 "${cestab}" "....chk ${cestab} cestab" ""
+}
+
 wait_connected()
 {
 	local listener_ns="${1}"
@@ -219,9 +228,11 @@ chk_msk_nr 2 "after MPC handshake "
 chk_msk_remote_key_nr 2 "....chk remote_key"
 chk_msk_fallback_nr 0 "....chk no fallback"
 chk_msk_inuse 2 "....chk 2 msk in use"
+chk_msk_cestab 2
 flush_pids
 
 chk_msk_inuse 0 "....chk 0 msk in use after flush"
+chk_msk_cestab 0
 
 echo "a" | \
 	timeout ${timeout_test} \
@@ -237,9 +248,11 @@ echo "b" | \
 wait_connected $ns 10001
 chk_msk_fallback_nr 1 "check fallback"
 chk_msk_inuse 1 "....chk 1 msk in use"
+chk_msk_cestab 1
 flush_pids
 
 chk_msk_inuse 0 "....chk 0 msk in use after flush"
+chk_msk_cestab 0
 
 NR_CLIENTS=100
 for I in `seq 1 $NR_CLIENTS`; do
@@ -261,9 +274,11 @@ done
 
 wait_msk_nr $((NR_CLIENTS*2)) "many msk socket present"
 chk_msk_inuse $((NR_CLIENTS*2)) "....chk many msk in use"
+chk_msk_cestab $((NR_CLIENTS*2))
 flush_pids
 
 chk_msk_inuse 0 "....chk 0 msk in use after flush"
+chk_msk_cestab 0
 
 mptcp_lib_result_print_all_tap
 exit $ret