linux - 更改 linux 网络设备的 TCP 超时

Question

我正在通过一个非常慢的接口编写 linux 设备驱动程序，其 ping 循环时间可能长达几分钟。当我尝试使用 TCP 在两个节点之间建立连接时，连接总是超时。

是否有一种方法可以在驱动程序中将 TCP 重传或握手超时设置得更长，或者是否有任何命令可以设置它？谢谢

Answer 1

您是否尝试过寻找这个问题的答案？一个快速的谷歌搜索给了我这个，这似乎直接解决了这个问题。总结是，设置net.ipv4.tcp_syn_retries决定了 TCP 连接可用的最大超时。

如果该文档 没有回答您的问题，您应该说明您尝试了什么以及行为与您的预期有何不同。

Answer 2

/proc/sys/net/ipv4/tcp_retries1
/proc/sys/net/ipv4/tcp_retries2

.

tcp_retries1 - INTEGER


 This value influences the time, after which TCP decides, that
    something is wrong due to unacknowledged RTO retransmissions,
    and reports this suspicion to the network layer.
    See tcp_retries2 for more details.

    RFC 1122 recommends at least 3 retransmissions, which is the
    default.


tcp_retries2 - INTEGER

This value influences the timeout of an alive TCP connection,
when RTO retransmissions remain unacknowledged.
Given a value of N, a hypothetical TCP connection following
exponential backoff with an initial RTO of TCP_RTO_MIN would
retransmit N times before killing the connection at the (N+1)th RTO.

The default value of 15 yields a hypothetical timeout of 924.6
seconds and is a lower bound for the effective timeout.
TCP will effectively time out at the first RTO which exceeds the
hypothetical timeout.

RFC 1122 recommends at least 100 seconds for the timeout,
which corresponds to a value of at least 8.