如何减少TCP connect()系统调用超时? [英] How to decrease TCP connect() system call timeout?

问题描述

在下面的命令中，我启用文件/dev/tcp/10.10.10.1/80 进行读写，并将其与文件描述符3关联:

In command below I enable file /dev/tcp/10.10.10.1/80 both for reading and writing and associate it with file descriptor 3:

$ time exec 3<>/dev/tcp/10.10.10.1/80
bash: connect: Operation timed out
bash: /dev/tcp/10.10.10.1/80: Operation timed out

real    1m15.151s
user    0m0.000s
sys     0m0.000s

这将自动尝试执行TCP三向握手.如果如上例所示无法访问10.10.10.1，则 connect 系统调用将尝试连接75秒.这75秒的超时时间是否由 bash 确定?还是该系统默认?最后但并非最不重要的一点是，有没有办法降低此超时值?

This automatically tries to perform TCP three-way handshake. If 10.10.10.1 is not reachable as in example above, then connect system call tries to connect for 75 seconds. Is this 75 second timeout determined by bash? Or is this system default? Last but not least, is there a way to decrease this timeout value?

推荐答案

由TCP确定.可以通过应用程序代码逐个减少它.

It is determined by TCP. It can be decreased on a per-socket basis by application code.

NB只有在完全没有响应的情况下，超时才会生效.如果有连接被拒绝，该错误将立即发生.

NB The timeout only takes effect if there is no response at all. If there is a connection refusal, the error occurs immediately.

这篇关于如何减少TCP connect()系统调用超时?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！