#!/usr/bin/env python3
from scapy.all import *
import ipaddress
from threading import Thread, Event
from time import sleep
import os


recv_count = 0

server_port = 50508



class Sniffer(Thread):
    def  __init__(self, iface="ens18"):

        super().__init__()

        self.daemon = True
        self.recv_count = 0
        self.socket = None
        self.iface = iface
        self.stop_sniffer = Event()

        self.debug_src = ""
        self.debug_sport = 0

        self.last_ack = 0
        self.last_seq = 0


    def run(self):
        self.socket = conf.L2listen(
            type=ETH_P_ALL,
            iface=self.iface,
            filter="ip"
        )

        sniff(
            opened_socket=self.socket,
            prn=self.handle_packet,

        )

    def join(self, timeout=None):
        self.stop_sniffer.set()
        super().join(timeout)


    def handle_debug_packet(self, payload):
        some_packet = IP(bytes(payload))
        print("genie debug packet..")
        some_packet.show()



    def handle_packet(self, packet):

        #ip_layer = packet.getlayer(IP)
        #print("[!] New Packet: {src} -> {dst}".format(src=ip_layer.src, dst=ip_layer.dst))

        if TCP in packet:
            tcp_sport = packet[TCP].sport
            tcp_dport = packet[TCP].dport

            if tcp_dport == server_port:
                print("sniffed a debug packet..")
                #packet.show()

                if self.recv_count > 3:
                    some_payload = packet[TCP].payload
                    self.handle_debug_packet(some_payload)


                    self.debug_src = packet[IP].src
                    self.debug_sport = tcp_sport

                    self.last_ack = packet[TCP].ack
                    self.last_seq = packet[TCP].seq

                self.recv_count += 1




# TODO: make this function be able to craft full custom packet including
# source IP, sport, protocol, flags, payload, etc.
def craft_send_payload(dip, dest_port):

    payload = ""
    send_pkt = IP(dst=dip, src="10.0.0.17") / TCP(dport=dest_port,sport=40404,flags="S") / "AAAAAAAA"
    send_bytes = bytes(send_pkt)
    payload = send_bytes

    print("debug send payload: " + str(payload))

    return payload




def get_send_payload():

    payload = "BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB"

    send_pkt = IP(dst="9.9.9.9", src="10.0.0.161") / TCP(dport=80,sport=40404,flags="S") / "AAAAAAAA"
    send_bytes = bytes(send_pkt)
    payload = send_bytes


    print("debug send payload: " + str(payload))

    return payload




def send_debug_packet(sniffer, is_custom):

    debug_port = sniffer.debug_sport
    debug_ip = sniffer.debug_src

    send_seq = sniffer.last_ack
    send_ack = sniffer.last_seq


    if debug_port == 0 or debug_ip == '':
        print("There was no debug source connection to send to")
        return

    print("sending debug packet to " + str(debug_ip) + ":" + str(debug_port))
    send_payload = ""

    if is_custom:

        print("\n\nEnter dest ip for packet..")
        dip = input("Enter IP: ")
        print("\n\nEnter dest port for packet..")
        dport = input("Enter port: ")
        send_payload = craft_send_payload(dip, int(dport))

    else:
        send_payload = get_send_payload()


    packet = IP(dst=debug_ip) / TCP(dport=debug_port, sport=server_port, flags='PA', seq=send_seq, ack=send_ack) / send_payload
    send(packet, iface="ens18")
    print("sent debug packet: ")
    packet.show()



def main():

    sniffer = Sniffer(iface='ens18')
    print('starting sniffer..')
    sniffer.start()
    time.sleep(3)


    done = False


    while not(done):

        print("Enter action to take..")
        print("1. Keep sniffing")
        print("2. Send test packet back")
        print("3. Craft custom packet to send from genie")
        print("4. Quit")

        answer = input("Enter answer: ")

        if answer == "1":
            print("sleeping for sniffer..")
            time.sleep(5)
        elif answer == "2":
            send_debug_packet(sniffer, False)
        elif answer == "3":
            send_debug_packet(sniffer, True)
        elif answer == "4":
            print("ending the sniffer")
            done = True
        
        print("user answer was: " + str(answer))
        print("\n")
        time.sleep(1)



    print("\n\nFinished sniffing for debug packets")


if __name__ == '__main__':
    main()