python linux下IP操作函数

import socket
import fcntl
import struct

def get_ip_address(ifname='eth0'):
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
ipaddr = socket.inet_ntoa(fcntl.ioctl(
s.fileno(),
0x8915,  # SIOCGIFADDR
struct.pack('256s', ifname[:15]))[20:24])
return ipaddr

def get_netmask(ifname='eth0'):
return socket.inet_ntoa(fcntl.ioctl(
socket.socket(socket.AF_INET, socket.SOCK_DGRAM),
35099,
struct.pack('256s', ifname))[20:24])

def get_default_gateway_linux():
with open("/proc/net/route") as fh:
for line in fh:
fields = line.strip().split()
if fields[1] != '00000000' or not int(fields[3], 16) & 2:
continue
return socket.inet_ntoa(struct.pack("<L", int(fields[2], 16)))

def get_dns(dns_number="1"):
counter = 0
with open("/etc/resolv.conf") as f:
content = f.readlines()
for line in content:
if "nameserver " in line:
counter= counter+1
if (str(counter) == dns_number):
return line[11:len(line)-1];