如何绑定到任何可用端口? [英] How to bind to any available port?

问题描述

我需要一个将UDP数据包发送到某些网络服务器并接收响应的应用程序.服务器会回复来自请求的相同端口号，因此我首先需要将套接字绑定()到任何UDP端口号.

I need an app that sends an UDP packet to some network server and receives the response. The server replies to the same port number where request came from, so I first need to bind() my socket to any UDP port number.

对UDP端口号进行硬编码是一个坏主意，因为同一台PC上运行的任何其他应用程序都可能会使用它.

Hardcoding the UDP port number is a bad idea, as it might be used by any other application running on the same PC.

是否可以将UDP套接字绑定到任何可用端口? IMO，这应该是一种快速获得空闲端口号的有效方法，例如， accept()函数.

Is there a way to bind an UDP socket to any port available? IMO it should be an effective way to quickly obtain a free port #, which is used by e.g. accept() function.

如果否，那么尝试绑定并检查WSAEADDRINUSE/EADDRINUSE状态的最佳策略是什么:依次尝试从1025或1025 + rand()或其他端口开始的端口?

If no, then what's the best strategy to try binding and check for WSAEADDRINUSE/EADDRINUSE status: try the ports sequentially starting from from 1025, or 1025+rand(), or some other?

推荐答案

致电 sendto 而不先调用bind，套接字将被自动绑定(绑定到空闲端口).

Call sendto without calling bind first, the socket will be bound automatically (to a free port).

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