selftests: netfilter: add checktool function

log_netns=$(sysctl -n net.netfilter.nf_log_all_netns)

nft --version > /dev/null 2>&1

checktool (){

	$1 > /dev/null 2>&1

	if [ $? -ne 0 ];then

	echo "SKIP: Could not run test without nft tool"

	exit $ksft_skip

fi

ip -Version > /dev/null 2>&1

if [ $? -ne 0 ];then

	echo "SKIP: Could not run test without ip tool"

	exit $ksft_skip

fi

which nc > /dev/null 2>&1

if [ $? -ne 0 ];then

	echo "SKIP: Could not run test without nc (netcat)"

		echo "SKIP: Could not $2"

		exit $ksft_skip

	fi

}

ip netns add nsr1

if [ $? -ne 0 ];then

	echo "SKIP: Could not create net namespace"

	exit $ksft_skip

fi

checktool "nft --version" "run test without nft tool"

checktool "ip -Version" "run test without ip tool"

checktool "which nc" "run test without nc (netcat)"

checktool "ip netns add nsr1" "create net namespace"

ip netns add ns1

ip netns add ns2