Python 3.4:未知格式代码"x"

我在Python3中遇到有关数据包嗅探器的问题.

I have issue about packet sniffer in Python3.

python版本:3.4

version of python: 3.4

我遵循了一些有效的教程，但是在我的计算机上不起作用. 此代码必须获取mac地址，将其转换为字符串，并在main()方法中应向我输出目标mac，源mac和协议.

I followed some tutorial that works, but not on my computer. This code has to get mac address, convert it to string and in main() method should print to me destination mac, source mac and protocol.

代码:sniffer_demo.py

code: sniffer_demo.py

import socket
import struct
import textwrap

def main():
    conn = socket.socket(socket.AF_PACKET, socket.SOCK_RAW, socket.ntohs(3))

    while True:
        raw_data, addr = conn.recvfrom(65536)
        # one's and zero's put to the method ehternet_frame
        dest_mac, src_mac, eth_proto, data = ethernet_frame(raw_data)
        print('\nEthernet Frame:')
        print('Destination: {}, Source: {}, Protocol: {}'.format(dest_mac, src_mac, eth_proto))


# Unpack ethernet frame
def ethernet_frame(data):
    dest_mac, src_mac, proto = struct.unpack('! 6s 6s H', data[:14])
    return get_mac_addr(dest_mac), get_mac_addr(src_mac), socket.htons(proto), data[14:]


# Return properly formatted MAC address: (ie AA:BB:CC:DD:EE:FF)
def get_mac_addr(bytes_addr):
    bytes_str = map('{:02x}'.format, bytes_addr)
    return ':'.join(bytes_str).upper()

main()

错误是:

Traceback (most recent call last):
  File "sniffer_demo.py", line 28, in <module>
    main()
  File "sniffer_demo.py", line 11, in main
    dest_mac, src_mac, eth_proto, data = ethernet_frame(raw_data)
  File "sniffer_demo.py", line 19, in ethernet_frame
    return get_mac_addr(dest_mac), get_mac_addr(src_mac), socket.htons(proto), data[14:]
  File "sniffer_demo.py", line 24, in get_mac_addr
    bytes_str = map('{:02x}'.format, bytes_addr)
ValueError: Unknown format code 'x' for object of type 'str'

该如何解决?