Retrieve data from encoded packet data without using third party libraries

ether.py

# simple class to retrive data from hexcode ,in this section it will retrieve source mac address , destination mac address
from com.talentica.ether_types import ether_types
from com.talentica.helper import create_hexcode_from_decoded_data_latin1


class Ether:

    # IEEE standard 802.1Q-2005
    ether_vlan_priorities = {
        0: 'Best Effort',
        1: 'Background',
        2: 'Excellent Effort',
        3: 'Critical Applications',
        4: 'Voice, < 10ms latency and jitter, Drop Eligible',
        5: 'Voice, < 10ms latency and jitter',
        6: 'Internetwork Control',
        7: 'Network Control'
    }

    def __init__(self, decoded_data):
        self.current_index = 0
        self.data = dict()
        self.destination_address = ':'.join(decoded_data[self.current_index:self.current_index + 6])
        self.data['dst_mac'] = self.destination_address
        self.current_index += 6
        self.source_address = ':'.join(decoded_data[self.current_index:self.current_index + 6])
        self.data['src_mac'] = self.source_address
        self.current_index += 6
        proto_type = ''.join(decoded_data[self.current_index: self.current_index + 2])
        self.data['type'] = ether_types.get(proto_type)
        self.current_index += 2
        vlan_details = decoded_data[self.current_index] + decoded_data[self.current_index + 1]
        self.current_index += 2
        # convert it to int and then to binary, remove prefix 0b and fill upto 16 bit
        if proto_type == '8100':
            vlan_details_bin = bin(int(vlan_details, 16))[2:].zfill(16)
            vlan_priority = int(vlan_details_bin[0:3], 2)
            vlan_priority = Ether.ether_vlan_priorities.get(vlan_priority)
            vlan_dei = 'Ineligible' if int(vlan_details_bin[3], 2) == 0 else 'Eligible'
            vlan_id = int(vlan_details_bin[4:], 2)
            self.data['vlan_priority'] = vlan_priority
            self.data['vlan_dei'] = vlan_dei
            self.data['vlan_id'] = vlan_id
            v_type = decoded_data[self.current_index] + decoded_data[self.current_index + 1]
            self.data['v_type'] = ether_types.get(v_type, v_type)

    def get_data(self):
        return self.data


if __name__ == '__main__':
    encoded_wired_data = '////////0E3Gwu+KgQAAAY/9vu8EAy4BAwU5duAKAgJsRwABAAAAEAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=='
    decoded_wired_data = create_hexcode_from_decoded_data_latin1(encoded_wired_data)
    ether_data = Ether(decoded_wired_data)
    print(ether_data.get_data())

ether_types.py

ether_types = {
    '0800': 'ipv4',
    '0806': 'arp',
    '0842': 'wake_on_lan',
    '22f0': 'avtp',
    '22f3': 'ietf_trill_protocol',
    '22ea': 'stream_reservation_proto',
    '6002': 'dec_mop_rc',
    '6003': 'decnet_phase_4',
    '6004': 'dec_lat',
    '8035': 'rarp',
    '809b': 'ethertalk',
    '80f3': 'aarp',
    '8100': 'vlan_tagged_frame',
    '8102': 'slpp',
    '8103': 'vlacp',
    '8137': 'ipx',
    '8204': 'qnx_qnet',
    '86dd': 'ipv6',
    '8808': 'ethernet_flow_control',
    '8809': 'lacp',
    '8819': 'cobranet',
    '8847': 'mpls_unicast',
    '8848': 'mpls_multicast',
    '8863': 'pppoe_discovery_stage',
    '8864': 'pppoe_session_stage',
    '887b': 'homeplug_1_0_mme',
    '888e': 'eap_over_lan',
    '8892': 'profinet_proto',
    '889a': 'hyper_scsi',
    '88a2': 'ata_over_ethernet',
    '88a4': 'ethercat_proto',
    '88a8': 'service_vlan',
    '88ab': 'ethernet_powerlink',
    '88b8': 'goose',
    '88b9': 'gse',
    '88ba': 'sampled_value_trans',
    '88bf': 'mikrotik_romon',
    '88cc': 'lldp',
    '88cd': 'sercos_3',
    '88e1': 'home_plug_green',
    '88e3': 'mrp',
    '88e5': 'mac_sec',
    '88e7': 'pbb',
    '88f7': 'ptp',
    '88f8': 'nc_si',
    '88fb': 'prp',
    '8902': 'cfm',
    '8906': 'fcoe',
    '8914': 'fcoe_initilization_proto',
    '8915': 'roce',
    '891d': 'tte',
    '893a': 'ieee_proto_1905_1',
    '892f': 'hsr',
    '9000': 'ethernet_config_testing_proto',
    'f1c1': 'redundancy_tag',
    '888e': 'port_based_nac_802_1x',
}

helper.py

# method used for retrieving hex dump values after decoding the encoded packet using base64. 
   
@staticmethod
def create_hexcode_from_decoded_data_latin1(pkt_encoded):
  pkt_decoded = base64.b64decode(pkt_encoded).decode('latin-1')
  hex_data_list = []
  for x in pkt_decoded:
    byte_data = bytes(x, 'latin-1')
    hex_data = ' '.join('{:02x}'.format(x) for x in byte_data)
    hex_data_list.append(hex_data)
    return hex_data_list