zapret/common/fwtype.sh

linux_ipt_avail() {
	exists iptables && exists ip6tables
}
linux_maybe_iptables_fwtype() {
	linux_ipt_avail && FWTYPE=iptables
}
linux_nft_avail() {
	exists nft
}
linux_fwtype() {
	[ -n "$FWTYPE" ] && return

	FWTYPE=unsupported

	linux_get_subsys
	if [ "$SUBSYS" = openwrt ]; then
		# Linux kernel is new enough if fw4 is there
		if [ -x /sbin/fw4 ] && linux_nft_avail; then
			FWTYPE=nftables
		else
			linux_maybe_iptables_fwtype
		fi
	else
		SUBSYS=
		# generic Linux
		# flowtable is implemented since kernel 4.16
		if linux_nft_avail && linux_min_version 4 16; then
			FWTYPE=nftables
		else
			linux_maybe_iptables_fwtype
		fi
	fi

	export FWTYPE
}

get_fwtype() {
	[ -n "$FWTYPE" ] && return

	local UNAME="$(uname)"

	case "$UNAME" in
	Linux)
		linux_fwtype
		;;
	FreeBSD)
		if exists ipfw; then
			FWTYPE=ipfw
		else
			FWTYPE=unsupported
		fi
		;;
	*)
		FWTYPE=unsupported
		;;
	esac

	export FWTYPE
}