zapret2/init.d/custom.d.examples.linux/80-dns-intercept

# this custom script feeds dns response data to main nfqws2 instance

zapret_custom_firewall()
{
	# $1 - 1 - run, 0 - stop
	local filt="-p udp --sport 53"
	local jump="-j NFQUEUE --queue-num $QNUM --queue-bypass"
	local chain lan lanifs

	get_lanif lanifs

	# router
	for lan in $lanifs; do
		[ "$DISABLE_IPV4" = 1 ] || ipt_add_del $1 FORWARD -o $lan $filt $jump
		[ "$DISABLE_IPV6" = 1 ] || ipt6_add_del $1 FORWARD -o $lan $filt $jump
	done
	# dns client server
	for chain in INPUT OUTPUT ; do
		[ "$DISABLE_IPV4" = 1 ] || ipt_add_del $1 $chain $filt $jump
		[ "$DISABLE_IPV6" = 1 ] || ipt6_add_del $1 $chain $filt $jump
	done
}

zapret_custom_firewall_nft()
{
	# stop logic is not required

	# dns client
	nft_add_chain forward_dns_feed "type filter hook forward priority mangle;"
	nft_add_rule forward_dns_feed oifname @lanif udp sport 53 queue num $QNUM bypass

	# router
	nft_add_chain input_dns_feed "type filter hook input priority mangle;"
	nft_add_rule input_dns_feed udp sport 53 queue num $QNUM bypass

	# dns server
	nft_add_chain output_dns_feed "type filter hook output priority mangle;"
	nft_add_rule output_dns_feed udp sport 53 queue num $QNUM bypass
}

zapret_custom_firewall_nft_flush()
{
	local chain
	for chain in forward_dns_feed input_dns_feed output_dns_feed; do
		nft_delete_chain $chain 2>/dev/null
	done
}