为什么％en0后缀无法在Python中连接本地链接的IPv6 TCP套接字? [英] Why doesn't a %en0 suffix work to connect a link-local IPv6 TCP socket in Python?

问题描述

大约一周前，StackOverflow上的某人问为什么他们的用于连接到IPv6链接本地地址的Python代码无法正常工作，我回答说，由于它是链接本地地址，因此他们需要添加％en0(或所需的本地接口名称)后缀到他们的目标IP地址.我以为我知道我在说什么，所以我在回答之前并没有真正测试过我的建议(可耻！).

A week or so ago someone on StackOverflow asked why their Python code for connecting to an IPv6 link-local address wasn't working, and I replied that since it was a link-local address they needed to add a %en0 (or whatever the desired local-interface-name is) suffix to their target IP address. I thought I knew what I was talking about, so I didn't actually test my suggestion before answering (shame on me!).

今天我去为自己使用了同样的技术，只是发现它似乎不起作用. :^(也就是说，此代码不起作用:

Today I went to use that same technique for myself, only to find that it doesn't seem to work. :^( That is, this code does not work:

>>> from socket import *
>>> s = socket(AF_INET6, SOCK_STREAM)
>>> s.connect(('fe80::21f:5bff:fe3f:1b36%en0', 2001))
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<string>", line 1, in connect
socket.error: [Errno 65] No route to host

另一方面，下面的代码可以正常工作(带或不带％en0后缀):

The following code, on the other hand, DOES work (with or without the %en0 suffix):

>>> from socket import *
>>> s = socket(AF_INET6, SOCK_STREAM)
>>> s.connect(('fe80::21f:5bff:fe3f:1b36%en0', 2001, 0, 6))
>>> 

...但是我不喜欢那样做，因为为了弄清楚要为最后一个参数提供哪个作用域ID整数，我必须执行一堆不是很便携的代码来进行迭代在本地接口列表中，找到名为"en0"的接口，并提取其作用域ID，这比我想要的要复杂得多.

... but I don't like doing it that way, because in order to figure out which scope ID integer to supply for the last argument, I have to execute a bunch of not-very-portable code to iterate over the local interfaces list, find the interface named 'en0', and extract its scope ID, which is more complexity overhead than I'd like to have.

鉴于connect()正在接受IP地址的％en0后缀，为什么它不按预期实际使用它来确定作用域ID?

Given that connect() is accepting the %en0 suffix to the IP address, why isn't it actually using it as expected to determine the scope ID?

FWIW，我正在MacOS/X 10.6.4下使用Python 2.6.1进行测试.

FWIW, I am testing with Python 2.6.1 under MacOS/X 10.6.4.

推荐答案

这是建立ipv6连接的正确方法:

This is the correct way to do an ipv6 connection:

>>> addrinfo = getaddrinfo('fe80::225:ff:fecd:5aa0%en0', 2001, AF_INET6, SOCK_STREAM)
>>> addrinfo
[(30, 1, 6, '', ('fe80::225:ff:fecd:5aa0%en0', 2001, 0, 4))]
>>> (family, socktype, proto, canonname, sockaddr) = addrinfo[0]
>>> s = socket(family, socktype, proto)
>>> s.connect(sockaddr)

getaddrinfo()将为您返回正确的数字范围和流信息.

getaddrinfo() will return the correct numerical scope and flow information for you.

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