正則匹配ipv4和ipv6，判斷ipv4和ipv6的合法性

python寫法，正則匹配ipv4和ipv6，並判斷其合法性。

import sys
import re

def is_ipv4(ip):
    p = re.compile(
        '^((25[0-5]|2[0-4]\d|[01]?\d\d?)\.){3}(25[0-5]|2[0-4]\d|[01]?\d\d?)$')
    if p.match(ip):
        return True
    else:
        return False

def is_ipv6(ip):
    p = re.compile('^((([0-9A-Fa-f]{1,4}:){7}[0-9A-Fa-f]{1,4})|(([0-9A-Fa-f]{1,4}:){1,7}:)|(([0-9A-Fa-f]{1,4}:){6}:[0-9A-Fa-f]{1,4})|(([0-9A-Fa-f]{1,4}:){5}(:[0-9A-Fa-f]{1,4}){1,2})|(([0-9A-Fa-f]{1,4}:){4}(:[0-9A-Fa-f]{1,4}){1,3})|(([0-9A-Fa-f]{1,4}:){3}(:[0-9A-Fa-f]{1,4}){1,4})|(([0-9A-Fa-f]{1,4}:){2}(:[0-9A-Fa-f]{1,4}){1,5})|([0-9A-Fa-f]{1,4}:(:[0-9A-Fa-f]{1,4}){1,6})|(:(:[0-9A-Fa-f]{1,4}){1,7})|(([0-9A-Fa-f]{1,4}:){6}(\\d|[1-9]\\d|1\\d{2}|2[0-4]\\d|25[0-5])(\\.(\\d|[1-9]\\d|1\\d{2}|2[0-4]\\d|25[0-5])){3})|(([0-9A-Fa-f]{1,4}:){5}:(\\d|[1-9]\\d|1\\d{2}|2[0-4]\\d|25[0-5])(\\.(\\d|[1-9]\\d|1\\d{2}|2[0-4]\\d|25[0-5])){3})|(([0-9A-Fa-f]{1,4}:){4}(:[0-9A-Fa-f]{1,4}){0,1}:(\\d|[1-9]\\d|1\\d{2}|2[0-4]\\d|25[0-5])(\\.(\\d|[1-9]\\d|1\\d{2}|2[0-4]\\d|25[0-5])){3})|(([0-9A-Fa-f]{1,4}:){3}(:[0-9A-Fa-f]{1,4}){0,2}:(\\d|[1-9]\\d|1\\d{2}|2[0-4]\\d|25[0-5])(\\.(\\d|[1-9]\\d|1\\d{2}|2[0-4]\\d|25[0-5])){3})|(([0-9A-Fa-f]{1,4}:){2}(:[0-9A-Fa-f]{1,4}){0,3}:(\\d|[1-9]\\d|1\\d{2}|2[0-4]\\d|25[0-5])(\\.(\\d|[1-9]\\d|1\\d{2}|2[0-4]\\d|25[0-5])){3})|([0-9A-Fa-f]{1,4}:(:[0-9A-Fa-f]{1,4}){0,4}:(\\d|[1-9]\\d|1\\d{2}|2[0-4]\\d|25[0-5])(\\.(\\d|[1-9]\\d|1\\d{2}|2[0-4]\\d|25[0-5])){3})|(:(:[0-9A-Fa-f]{1,4}){0,5}:(\\d|[1-9]\\d|1\\d{2}|2[0-4]\\d|25[0-5])(\\.(\\d|[1-9]\\d|1\\d{2}|2[0-4]\\d|25[0-5])){3}))$')
    if p.match(ip):
        return True
    else:
        return False

def check_ip(ip):
    if is_ipv4(ip):
        print "IPv4"
    elif is_ipv6(ip):
        print "IPv6"
    else:
        print "Neither"


ip_str = sys.stdin.readline()
check_ip(ip_str)

其中，

ipv4的正則爲：

^((25[0-5]|2[0-4]\d|[01]?\d\d?)\.){3}(25[0-5]|2[0-4]\d|[01]?\d\d?)$

ipv6的正則爲：

^((([0-9A-Fa-f]{1,4}:){7}[0-9A-Fa-f]{1,4})|(([0-9A-Fa-f]{1,4}:){1,7}:)|(([0-9A-Fa-f]{1,4}:){6}:[0-9A-Fa-f]{1,4})|(([0-9A-Fa-f]{1,4}:){5}(:[0-9A-Fa-f]{1,4}){1,2})|(([0-9A-Fa-f]{1,4}:){4}(:[0-9A-Fa-f]{1,4}){1,3})|(([0-9A-Fa-f]{1,4}:){3}(:[0-9A-Fa-f]{1,4}){1,4})|(([0-9A-Fa-f]{1,4}:){2}(:[0-9A-Fa-f]{1,4}){1,5})|([0-9A-Fa-f]{1,4}:(:[0-9A-Fa-f]{1,4}){1,6})|(:(:[0-9A-Fa-f]{1,4}){1,7})|(([0-9A-Fa-f]{1,4}:){6}(\\d|[1-9]\\d|1\\d{2}|2[0-4]\\d|25[0-5])(\\.(\\d|[1-9]\\d|1\\d{2}|2[0-4]\\d|25[0-5])){3})|(([0-9A-Fa-f]{1,4}:){5}:(\\d|[1-9]\\d|1\\d{2}|2[0-4]\\d|25[0-5])(\\.(\\d|[1-9]\\d|1\\d{2}|2[0-4]\\d|25[0-5])){3})|(([0-9A-Fa-f]{1,4}:){4}(:[0-9A-Fa-f]{1,4}){0,1}:(\\d|[1-9]\\d|1\\d{2}|2[0-4]\\d|25[0-5])(\\.(\\d|[1-9]\\d|1\\d{2}|2[0-4]\\d|25[0-5])){3})|(([0-9A-Fa-f]{1,4}:){3}(:[0-9A-Fa-f]{1,4}){0,2}:(\\d|[1-9]\\d|1\\d{2}|2[0-4]\\d|25[0-5])(\\.(\\d|[1-9]\\d|1\\d{2}|2[0-4]\\d|25[0-5])){3})|(([0-9A-Fa-f]{1,4}:){2}(:[0-9A-Fa-f]{1,4}){0,3}:(\\d|[1-9]\\d|1\\d{2}|2[0-4]\\d|25[0-5])(\\.(\\d|[1-9]\\d|1\\d{2}|2[0-4]\\d|25[0-5])){3})|([0-9A-Fa-f]{1,4}:(:[0-9A-Fa-f]{1,4}){0,4}:(\\d|[1-9]\\d|1\\d{2}|2[0-4]\\d|25[0-5])(\\.(\\d|[1-9]\\d|1\\d{2}|2[0-4]\\d|25[0-5])){3})|(:(:[0-9A-Fa-f]{1,4}){0,5}:(\\d|[1-9]\\d|1\\d{2}|2[0-4]\\d|25[0-5])(\\.(\\d|[1-9]\\d|1\\d{2}|2[0-4]\\d|25[0-5])){3}))$

的確ipv6的正則比較長，但是確實是ipv6比較複雜很多啊。