在线关闭 CLOSE_WAIT状态TCP连接

1、查看某个端口的所有TCP连接：

[root@Centos projects]# netstat -anp | grep
tcp6              :::                 :::*                    LISTEN      /java
tcp6              192.168.229.140:    192.168.229.1:     CLOSE_WAIT  /java
tcp6              192.168.229.140:    192.168.229.1:     CLOSE_WAIT  /java
tcp6              192.168.229.140:    192.168.229.1:     CLOSE_WAIT  /java
tcp6              192.168.229.140:    192.168.229.1:     CLOSE_WAIT  /java
tcp6              192.168.229.140:    192.168.229.1:     CLOSE_WAIT  /java
[root@Centos projects]# 

2、获取 CLOSE_WAIT 状态连接的文件描述符：

[root@Centos projects]# lsof -np  | grep "CLOSE_WAIT"
java     root   27u     IPv6                     0t0      TCP 192.168.229.140:simplifymedia->192.168.229.1: (CLOSE_WAIT)
java     root   28u     IPv6                     0t0      TCP 192.168.229.140:simplifymedia->192.168.229.1: (CLOSE_WAIT)
java     root   30u     IPv6                     0t0      TCP 192.168.229.140:simplifymedia->192.168.229.1: (CLOSE_WAIT)
java     root   31u     IPv6                     0t0      TCP 192.168.229.140:simplifymedia->192.168.229.1: (CLOSE_WAIT)
java     root   33u     IPv6                     0t0      TCP 192.168.229.140:simplifymedia->192.168.229.1: (CLOSE_WAIT)
[root@Centos projects]# lsof -np  | grep "CLOSE_WAIT" | awk '{print $4}'
27u
28u
30u
31u
33u
[root@Centos projects]# 

3、使用GDB关闭 CLOSE_WAIT状态连接：

[root@Centos projects]# gdb -p 4931　　# 连接到 4931 进程
GNU gdb (GDB) Red Hat Enterprise Linux 7.6.-.el7
Copyright (C)  Free Software Foundation, Inc.
License GPLv3+: GNU GPL version  or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-redhat-linux-gnu".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>.
Attaching to process
...（略去内容）...
(gdb) 　　　　　　　　　　# 这里为 gdb 命令提示符

然后根据文件描述符关闭指定的 socket 连接：

(gdb) call close(27u)　　# 27u即 close_wait 状态连接的文件描述符
...(略去内容)...