在solaris 中套接字错误EINPROGRESS 的可能原因是什么? [英] What are possible reason for socket error EINPROGRESS in solaris?

问题描述

Solaris 中套接字错误 EINPROGRESS 的可能原因是什么?我们如何检查根本原因?

What are possible reason for socket error EINPROGRESS in Solaris? How we can check the root cause?

tcp api 是:连接

tcp api is : connect

推荐答案

您有一个非阻塞套接字，并且正在其中调用 connect().由于 connect() 需要发生 3 次握手(所以是网络往返)，它要么阻止等待阻塞套接字中的 SYN-ACK，要么给你一些指示它没有成功但在非阻塞套接字中.通常，非阻塞套接字返回 EAGAIN/EWOULDBLOCK 以告诉您它们无法进行，您应该再试一次:这不完全是您的情况，connect() 在没有免费的临时端口告诉你你应该稍后再试；所以非阻塞连接还有另一个错误:EINPROGRESS，它告诉你操作正在进行中，你应该稍后检查它的状态.

You have a non-blocking socket and you are calling connect() in it. Since connect() needs the 3-way handshake to happen (so a network roundtrip), it either blocks waiting for the SYN-ACK in blocking sockets, or gives you some indication that it hasn't succeded yet in non-blocking sockets. Normally, non-blocking sockets return EAGAIN/EWOULDBLOCK to tell you that they couldn't progress and you should try again: this is not exactly your case, connect() returns EAGAIN/EWOULDBLOCK when there are no free ephemeral ports to tell you that you should try again later; so there is another error for non-blocking connect: EINPROGRESS, which tells you that the operation is in progress and you should check its status later.

为了稍后检查状态，套接字将准备好可写，因此您可以使用 select()/poll()/... 来测试它，之后您必须getsockopt(...SO_ERROR...) 来获取 connect() 操作的成功/失败状态.

To check the status later, the socket will become ready for writability, so you can use select()/poll()/... to test for that, after which you'll have to getsockopt(...SO_ERROR...) to get the success/failure status of your connect() operation.

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