Add a IP to another rule matching hex in iptables linux

Question

iptables -t raw -A PREROUTING -p udp --dport 4578 -m string --hex-string '|fefffffffffffffffff77f12|'

How can I whitelist the IP having the above hexx string automatically on Iptables.

I'll be dropping all incoming traffic on iptables and allowing only the packet with above hex string. Whenever we receive a packet with above hex string the I want to whitelist his IP on Iptables immediately. So that all traffic from that particular IP gets passed

Thanks in Advance