是否总是需要绑定套接字? [英] Is it always required to bind a socket?

问题描述

嗯，我的问题可能看起来很基本，但是我是网络编程方面的新手. 我想知道:

Well, my question may look like a basic stuff, but i am new to network programming side. I wish to know:

1)是否总是需要绑定套接字才能接收来自该套接字的消息?我看到了一个嗅探器代码(原始套接字)，其中一个代码直接调用recvfrom，而另一个代码中它调用bind然后是接收.

1) Is it always required to bind a socket in order to receive message from that? I saw a sniffer code (raw socket) one in which directly it is invoking recvfrom and another piece of code in which it is invoking bind and then a receive.

2)AF_ *和PF_ *系列有什么区别?后者与POSIX有关吗? 推荐哪一个?

2) What is the difference between the AF_* and PF_* family? Is the later related to POSIX? Which is the one recommended ?

推荐答案

不，您不需要bind().

No, you don't need to bind().

如果您打算使用connect或使用sendto()将数据包发送到目标的TCP或UDP套接字，则当您尝试执行以下操作时，内核会自动将套接字绑定到合适的端口号连接或发送.通常，这是首选方式.绑定客户端套接字被认为是有害的.

If you're using a TCP or UDP socket where you are planning to either connect() or send a packet to a destination with sendto(), the kernel will automatically bind the socket to a suitable port number when you try to connect or send. This is generally the preferred way. bind()ing client sockets is considered harmful.

AF_UNIX套接字也是如此-客户端不需要绑定，并且通常不应这样做.

The same is also true of AF_UNIX sockets - the client side does not need to bind, and should not do so normally.

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