sniffer.py

import socket
import textwrap
from networking.ethernet import Ethernet
from networking.ipv4 import IPv4
from networking.icmp import ICMP
from networking.tcp import TCP
from networking.udp import UDP
from networking.pcap import Pcap

TAB_1 = '\t - '
TAB_2 = '\t\t - '
TAB_3 = '\t\t\t - '
TAB_4 = '\t\t\t\t - '

DATA_TAB_1 = '\t '
DATA_TAB_2 = '\t\t '
DATA_TAB_3 = '\t\t\t '
DATA_TAB_4 = '\t\t\t\t '


def main():
    pcap = Pcap('capture.pcap')
    conn = socket.socket(socket.AF_PACKET, socket.SOCK_RAW, socket.ntohs(3))

    while True:
        raw_data, addr = conn.recvfrom(65535)
        pcap.write(raw_data)
        eth = Ethernet(raw_data)

        print('\nEthernet Frame:')
        print(TAB_1 + 'Destination: {}, Source: {}, Protocol: {}'.format(eth.dest_mac, eth.src_mac, eth.proto))

        # IPv4
        if eth.proto == 8:
            ipv4 = IPv4(eth.data)
            print(TAB_1 + 'IPv4 Packet:')
            print(TAB_2 + 'Version: {}, Header Length: {}, TTL: {},'.format(ipv4.version, ipv4.header_length, ipv4.ttl))
            print(TAB_2 + 'Protocol: {}, Source: {}, Target: {}'.format(ipv4.proto, ipv4.src, ipv4.target))

            # ICMP
            if ipv4.proto == 1:
                icmp = ICMP(ipv4.data)
                print(TAB_1 + 'ICMP Packet:')
                print(TAB_2 + 'Type: {}, Code: {}, Checksum: {},'.format(icmp.type, icmp.code, icmp.checksum))
                print(TAB_2 + 'Data:')
                print(format_multi_line(DATA_TAB_3, icmp.data))

            # TCP
            elif ipv4.proto == 6:
                tcp = TCP(ipv4.data)
                print(TAB_1 + 'TCP Segment:')
                print(TAB_2 + 'Source Port: {}, Destination Port: {}'.format(tcp.src_port, tcp.dest_port))
                print(TAB_2 + 'Sequence: {}, Acknowledgment: {}'.format(tcp.sequence, tcp.acknowledgment))
                print(TAB_2 + 'Flags:')
                print(TAB_3 + 'URG: {}, ACK: {}, PSH: {}, RST: {}, SYN: {}, FIN:{}'.format(tcp.flag_urg, tcp.flag_ack, tcp.flag_psh, tcp.flag_rst, tcp.flag_syn, tcp.flag_fin))
                print(TAB_2 + 'Data:')
                print(format_multi_line(DATA_TAB_3, tcp.data))

            # UDP
            elif ipv4.proto == 17:
                udp = UDP(ipv4.data)
                print(TAB_1 + 'UDP Segment:')
                print(TAB_2 + 'Source Port: {}, Destination Port: {}, Length: {}'.format(udp.src_port, udp.dest_port, udp.size))

            # Other IPv4
            else:
                print(TAB_1 + 'Data:')
                print(format_multi_line(DATA_TAB_2, ipv4.data))

        else:
            print('Data:')
            print(format_multi_line(DATA_TAB_1, eth.data))

    pcap.close()


# Formats multi-line data
def format_multi_line(prefix, string, size=80):
    size -= len(prefix)
    if isinstance(string, bytes):
        string = ''.join(r'\x{:02x}'.format(byte) for byte in string)
        if size % 2:
            size -= 1
    return '\n'.join([prefix + line for line in textwrap.wrap(string, size)])


main()