如何彻底摧毁在C套接字连接 [英] How to completely destroy a socket connection in C

问题描述

我已经用插座在Linux聊天客户端，我希望彻底摧毁连接。以下是code的相关部分：

I have made a chat client in linux using socket, and i wish to destroy the connection completely. Following is the relevant portions of the code:

int sock, connected, bytes_recieved , true = 1, pid;  
char send_data [1024] , recv_data[1024];     
struct sockaddr_in server_addr,client_addr;    
int sin_size;
label:
if ((sock = socket(AF_INET, SOCK_STREAM, 0)) == -1)
{
    perror("Socket");
    exit(1);
}
if (setsockopt(sock,SOL_SOCKET,SO_REUSEADDR,&true,sizeof(int)) == -1)
{
    perror("Setsockopt");
    exit(1);
}
server_addr.sin_family = AF_INET;         
server_addr.sin_port = htons(3128);     
server_addr.sin_addr.s_addr = INADDR_ANY; 
bzero(&(server_addr.sin_zero),8); 
if (bind(sock, (struct sockaddr *)&server_addr, sizeof(struct sockaddr))== -1)
{
    perror("Unable to bind");
    exit(1);
}
if (listen(sock, 5) == -1)
{
    perror("Listen");
    exit(1);
}
printf("\nTCPServer Waiting for client on port 3128");
fflush(stdout);
connected = accept(sock, (struct sockaddr *)&client_addr,&sin_size);
//necessary code
close(sock);
goto label;

但接近（袜子）不列入似乎关闭彻底摧毁的连接，因为要去'标签'的code正在退出显示错误消息后

but the close(sock) doesnot seem to close the destroy the connection completely, because after going to 'label' the code is exiting showing the error message

Unable to bind: Address already in use

这是连接不会再次发生。能有什么问题呢？先谢谢了。

That is the connection is not happening again. What can the problem be? Thanks in advance.

编辑：其实我要的是，当我破坏了连接后，运行从一开始的剧本，它应该是一个新的程序运行什么。我该怎么办呢？

What I actually want is, when I run the script from the beginning after destroying the connection, it should run as a fresh program. How can I do it?

推荐答案

的关闭呼叫才标志着TCP套接字关闭。它不是由过程可用了。
但是，内核可能仍持有一些资源，期限（TIME_WAIT，2毫升等东西）。

The close call only marks the TCP socket closed. It is not usable by process anymore. But kernel may still hold some resources for a period (TIME_WAIT, 2MLS etc stuff).

SO_REUSEADDR的设置应取消绑定的问题。

Setting of SO_REUSEADDR should remove binding problems.

所以一定的那个值真正真是非零致电时的setsockopt （溢出错误可能覆盖它）：

So be sure that value of true is really non-zero when calling setsockopt (overflow bug may overwrite it):

true = 1;
setsockopt(sock,SOL_SOCKET,SO_REUSEADDR,&true,sizeof(int))

有 PID 变量是您code。如果你使用叉（用于启动连接处理PROCESSS），那么你应该关闭袜子在不过程中也需要它。

There is pid variable is your code. If you use fork (for starting connection handling processs), then you should close sock also in the process which does not need it.

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