zapret/init.d/sysv/custom.d.examples/50-dht4all

# this custom script runs desync to DHT packets with udp payload length 101..399 , without ipset/hostlist filtering
# need to add to config : NFQWS_OPT_DESYNC_DHT="--dpi-desync=fake --dpi-desync-ttl=5"

alloc_dnum DNUM_DHT4ALL
alloc_qnum QNUM_DHT4ALL

zapret_custom_daemons()
{
        # stop logic is managed by procd

        local opt="--qnum=$QNUM_DHT4ALL $NFQWS_OPT_BASE $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_connbytes 1:1"
        local desync="-m mark ! --mark $DESYNC_MARK/$DESYNC_MARK"

        f='-p udp -m length --length 109:407 -m u32 --u32'
	uf4='0>>22&0x3C@8>>16=0x6431'
	uf6='48>>16=0x6431'
        fw_nfqws_post $1 "$f $uf4 $desync $first_packet_only"  "$f $uf6 $desync $first_packet_only" $QNUM_DHT4ALL

}
zapret_custom_firewall_nft()
{
        # stop logic is not required

        local f
        local first_packet_only="$nft_connbytes 1"
        local desync="mark and $DESYNC_MARK == 0"

        f="meta length 109-407 meta l4proto udp @th,64,16 0x6431"
        nft_fw_nfqws_post "$f $desync $first_packet_only" "$f $desync $first_packet_only" $QNUM_DHT4ALL
}