Linux:是否存在超时的套接字读取或接收? [英] Linux: is there a read or recv from socket with timeout?

问题描述

如何尝试在超时的情况下从套接字读取数据? 我知道选择，pselect，轮询具有超时字段，但是使用它们会禁用tcp reno堆栈中的"tcp快速路径".

How can I try to read data from socket with timeout? I know, select, pselect, poll, has a timeout field, but using of them disables "tcp fast-path" in tcp reno stack.

我唯一的想法是在循环中使用recv(fd，...，MSG_DONTWAIT)

The only idea I have is to use recv(fd, ..., MSG_DONTWAIT) in a loop

推荐答案

您可以使用 setsockopt 函数设置接收操作超时:

You can use the setsockopt function to set a timeout on receive operations:

SO_RCVTIMEO

设置超时值，该值指定 输入的最长时间 函数等待，直到完成.它 接受带有 秒数和微秒 指定限制多长时间 等待输入操作 完全的.如果接收操作有 封锁了这么多时间，没有 接收额外的数据，它应该 返回带有部分计数或错误号 如果没有，则设置为[EAGAIN]或[EWOULDBLOCK] 数据已接收.此的默认值 选项为零，表示一个 接收操作不得超时. 此选项采用timeval结构. 请注意，并非所有的实现 允许设置此选项.

Sets the timeout value that specifies the maximum amount of time an input function waits until it completes. It accepts a timeval structure with the number of seconds and microseconds specifying the limit on how long to wait for an input operation to complete. If a receive operation has blocked for this much time without receiving additional data, it shall return with a partial count or errno set to [EAGAIN] or [EWOULDBLOCK] if no data is received. The default for this option is zero, which indicates that a receive operation shall not time out. This option takes a timeval structure. Note that not all implementations allow this option to be set.

// LINUX
struct timeval tv;
tv.tv_sec = timeout_in_seconds;
tv.tv_usec = 0;
setsockopt(sockfd, SOL_SOCKET, SO_RCVTIMEO, (const char*)&tv, sizeof tv);

// WINDOWS
DWORD timeout = timeout_in_seconds * 1000;
setsockopt(socket, SOL_SOCKET, SO_RCVTIMEO, (const char*)&timeout, sizeof timeout);

// MAC OS X (identical to Linux)
struct timeval tv;
tv.tv_sec = timeout_in_seconds;
tv.tv_usec = 0;
setsockopt(sockfd, SOL_SOCKET, SO_RCVTIMEO, (const char*)&tv, sizeof tv);

在Windows上

据报道，应在调用bind之前完成.我已经通过实验验证，它可以在Linux和OS X上的bind之前或之后完成.

Reportedly on Windows this should be done before calling bind. I have verified by experiment that it can be done either before or after bind on Linux and OS X.

这篇关于Linux:是否存在超时的套接字读取或接收?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！