| import cProfile | |
| import functools | |
| import pstats | |
| from cStringIO import StringIO | |
| def profile(func): | |
| @functools.wraps(func) | |
| def wrapped(*args, **kwargs): |
| @startuml | |
| ' uncomment the line below if you're using computer with a retina display | |
| ' skinparam dpi 300 | |
| !define Table(name,desc) class name as "desc" << (T,#FFAAAA) >> | |
| ' we use bold for primary key | |
| ' green color for unique | |
| ' and underscore for not_null | |
| !define primary_key(x) <b>x</b> | |
| !define unique(x) <color:green>x</color> | |
| !define not_null(x) <u>x</u> |
| # -*- coding: utf-8 -*- | |
| """ | |
| hash_ring | |
| ~~~~~~~~~~~~~~ | |
| Implements consistent hashing that can be used when | |
| the number of server nodes can increase or decrease (like in memcached). | |
| Consistent hashing is a scheme that provides a hash table functionality | |
| in a way that the adding or removing of one slot | |
| does not significantly change the mapping of keys to slots. |
| /** | |
| * Here's a turing machine that fits into a tweet with an example program. | |
| * Original tweet: https://twitter.com/mrrrgn/status/630419814666780673 | |
| * Gif: http://i.imgur.com/4t31zA2.gif | |
| * Turing machines: https://www.youtube.com/watch?v=dNRDvLACg5Q | |
| * | |
| * Think this is neat? Consider following me for more computer silliness: | |
| * twitter.com/mrrrgn or rss my blog linuxpoetry.com | |
| **/ |
| # coding=utf-8 | |
| from __future__ import unicode_literals | |
| s = '你好' | |
| u = u'你好' |
由于路由管控系统的建立，实时动态黑洞路由已成为最有效的封锁手段，TCP连接重置和DNS污染成为次要手段，利用漏洞的穿墙方法已不再具有普遍意义。对此应对方法是多样化协议的VPN来抵抗识别。这里介绍一种太简单、有时很朴素的“穷人VPN”。
朴素VPN只需要一次内核配置（Linux内核），即可永久稳定运行，不需要任何用户态守护进程。所有流量转换和加密全部由内核完成，原生性能，开销几乎没有。静态配置，避免动态握手和参数协商产生指纹特征导致被识别。并且支持NAT，移动的内网用户可以使用此方法。支持广泛，基于L2TPv3标准，Linux内核3.2+都有支持，其他操作系统原则上也能支持。但有两个局限：需要root权限；一个隧道只支持一个用户。
朴素VPN利用UDP封装的静态L2TP隧道实现VPN，内核XFRM实现静态IPsec。实际上IP-in-IP隧道即可实现VPN，但是这种协议无法穿越NAT，因此必须利用UDP封装。内核3.18将支持Foo-over-UDP，在UDP里面直接封装IP，与静态的L2TP-over-UDP很类似。
| #!/usr/bin/env python3 | |
| # coding=utf-8 | |
| from __future__ import print_function | |
| from weakref import proxy | |
| integer_type = (int, long) | |
| class EnumAttr(object): | |
| def __init__(self, cls, name, value): |