import sys
from scapy.all import sniff, send, IP, IPv6, Packet, Raw, Ether, sendp
from datetime import datetime


def modify_packet(packet: Packet):
    global modifications
    global seen
    if packet.haslayer(IP):
        if packet[IP].ttl != 65:
            packet[IP].ttl = 65
            modifications += 1
    elif packet.haslayer(IPv6):
        if packet[IPv6].ttl != 65:
            packet[IPv6].ttl = 65
            modifications += 1
    seen += 1
    #Can be extented with other protocols which have TTL
    sendp(packet, iface=sys.argv[1])


if __name__ == "__main__":
    modifications = 0
    seen = 0
    if len(sys.argv) != 2:
        print(f"Usage: {sys.argv[0]} <interface>")
        sys.exit(1)

    interface = sys.argv[1]

    start_time = datetime.now()
    print(f"Script started at: {start_time.strftime('%Y-%m-%d %H:%M:%S')}")

    packets = sniff(filter="ip or ip6", iface=interface, timeout=2.5*1, prn=modify_packet)

    end_time = datetime.now()
    print(f"Script ended at: {end_time.strftime('%Y-%m-%d %H:%M:%S')}")
    print(f"{modifications} ip(v6) packets modified")
    print(f"{seen} total ip(v6) packets seen")