# this custom script runs desync to DHT packets with udp payload length >=5 , without ipset/hostlist filtering
# NOTE: @ih requires nft 1.0.1+ and updated kernel version. it's confirmed to work on 5.15 (openwrt 23) and not work on 5.10 (openwrt 22)

# can override in config :
NFQWS_OPT_DESYNC_DHT="${NFQWS_OPT_DESYNC_DHT:---payload dht --lua-desync=dht_dn}"
# set it to "keepalive" to fool all packets, not just the first. or set number of packets to be fooled.
NFQWS_OPT_DHT_PKT_OUT=${NFQWS_OPT_DHT_PKT_OUT:-20}

alloc_dnum DNUM_DHT4ALL
alloc_qnum QNUM_DHT4ALL

zapret_custom_daemons()
{
	# $1 - 1 - add, 0 - stop

	local opt="--qnum=$QNUM_DHT4ALL $NFQWS_OPT_DESYNC_DHT"
	do_nfqws $1 $DNUM_DHT4ALL "$opt"
}
zapret_custom_firewall()
{
	# $1 - 1 - run, 0 - stop

	local f uf4 uf6
	local first_packet_only=$(ipt_first_packets $NFQWS_OPT_DHT_PKT_OUT)

	f='-p udp -m u32 --u32'
	uf4='0>>22&0x3C@4>>16=13:0xFFFF&&0>>22&0x3C@8>>16=0x6431:0x6432'
	uf6='44>>16=13:0xFFFF&&48>>16=0x6431:0x6432'
	fw_nfqws_post $1 "$f $uf4 $first_packet_only"  "$f $uf6 $first_packet_only" $QNUM_DHT4ALL
}
zapret_custom_firewall_nft()
{
	# stop logic is not required

        local f
	local first_packet_only=$(nft_first_packets $NFQWS_OPT_DHT_PKT_OUT)

        f="udp length ge 13 meta l4proto udp @ih,0,16 0x6431-0x6432"
        nft_fw_nfqws_post "$f $first_packet_only" "$f $first_packet_only" $QNUM_DHT4ALL
}
