有关Black-Hat Python书籍中的代码的问题

Question

运行代码时没有看到任何输出。我使用的是Linux计算机，但无法正常工作。

我重新编写了代码，但是什么都没有改变，但终端仍然看不到任何输出

import socket
import os
import struct
from ctypes import *

host = "192.168.0.187"

class IP(Structure):
    _fields_ = [
        ("ihl", c_ubyte, 4),
        ("version", c_ubyte, 4),
        ("tos", c_ubyte),
        ("len", c_ushort),
        ("id", c_ushort),
        ("offset", c_ushort),
        ("ttl", c_ubyte),
        ("protocol_num", c_ubyte),
        ("sum", c_ushort),
        ("src", c_ulong),
        ("dst", c_ulong)
    ]

    def __new__(self, socket_buffer=None):
        return self.from_buffer_copy(socket_buffer)

    def __init__(self, socket_buffer=None):

         self.protocol_map = {1:"ICMP", 6:"TCP", 17:"UDP"}

         self.src_address = socket.inet_ntoa(struct.pack("<L",self.src))
         self.dst_address = socket.inet_ntoa(struct.pack("<L",self.dst))

         try:
             self.protocol = self.protocol_map[self.protocol_num]
         except:
             self.protocol = str(self.protocol_num)

if os.name == "nt":
    socket_protocol = socket.IPPROTO_IP
else:
    socket_protocol = socket.IPPROTO_ICMP

sniffer = socket.socket(socket.AF_INET, socket.SOCK_RAW,        socket_protocol)
sniffer.bind((host, 0))
sniffer.setsockopt(socket.IPPROTO_IP, socket.IP_HDRINCL, 1)

if os.name == "nt":
    sniffer.ioctl(socket.SIO_RCVALL, socket.RCVALL_ON)
try:
    while True:

         raw_buffer = sniffer.recvfrom(65565)[0]

         ip_header = IP(raw_buffer[0:20])

         print "Protocol: %s %s -> %s" % (ip_header.protocol, ip_header.src_
address, ip_header.dst_address)

except KeyboardInterrupt:

     if os.name == "nt":
         sniffer.ioctl(socket.SIO_RCVALL, socket.RCVALL_OFF)

在终端中运行它之后，我什么也看不到。该代码来自Black-Hat Python书。