上海网站开发一对一培训,网站主机的选择与优化,备案个人网站名称,重庆森林电影完整版1、在linux下#xff0c;测试tcp保活#xff0c;可以使用tcp自带keepalive功能。
2、几个重要参数#xff1a; tcp_keepalive_time#xff1a;对端在指定时间内没有数据传输#xff0c;则向对端发送一个keepalive packet#xff0c;单位#xff1a;秒 tcp_keep…1、在linux下测试tcp保活可以使用tcp自带keepalive功能。
2、几个重要参数 tcp_keepalive_time对端在指定时间内没有数据传输则向对端发送一个keepalive packet单位秒 tcp_keepalive_intvl向对端发送了一个keepalive packet,如果对端无响应则等待tcp_keepalive_intvl秒后再次发送一个keepalive packet tcp_keepalive_probes向对端发送一个keepalive packet如果对端没有响应重发的次数,如果tcp_keepalive_probes次数后对端都没有响应则表示这个socket已经断开系统会差生连接断开事件本地就可以关闭这个socket上连接。
3、修改三个参数的系统默认值 上述三个参数当前配置可以在 /proc/sys/net/ipv4查看 可以使用cat查看具体配置比如 全局设置:可更改/etc/sysctl.conf,加上: sudo vim /etc/sysctl.conf net.ipv4.tcp_keepalive_intvl 20 net.ipv4.tcp_keepalive_probes 3 net.ipv4.tcp_keepalive_time 60 保存wq 重启系统sudo reboot
4、编程设置keeepalive:
#include netinet/tcp.h/*开始设置保活机制*/int val 1;if (setsockopt(nc-sock, SOL_SOCKET, SO_KEEPALIVE, val, sizeof val) ! 0)
{perror(Set SO_KEEPALIVE fail);}/* Default settings are more or less garbage, with the keepalive time* set to 7200 by default on Linux. Modify settings to make the feature* actually useful. *//* Send first probe after interval. */val 10;if (setsockopt(nc-sock, IPPROTO_TCP, TCP_KEEPIDLE, val, sizeof(val)) 0)
{perror(Set TCP_KEEPIDLE fail);}/* Send next probes after the specified interval. Note that we set the* delay as interval / 3, as we send three probes before detecting* an error (see the next setsockopt call). */val 3;if (setsockopt(nc-sock, IPPROTO_TCP, TCP_KEEPINTVL, val, sizeof(val)) 0)
{perror(Set TCP_KEEPINTVL fail);}/* Consider the socket in error state after three we send three ACK* probes without getting a reply. */val 3;if (setsockopt(nc-sock, IPPROTO_TCP, TCP_KEEPCNT, val, sizeof(val)) 0)
{perror(Set TCP_KEEPCNT fail);}
5、查看通讯情况打开wireshark,在过滤器输入设置keepalive的Ip格式为ip.addrxxx.xxx.xxx.xxx 上图可以看到每隔10秒钟发送了一个keepalive packet.因为上述代码中我们设置的TCP_KEEPIDLE10
