对方网络非正常断开检测方法

windows下

此处的”非正常断开”指TCP连接不是以优雅的方式断开,如网线故障等物理链路的原因,还有突然主机断电等原因

有两种方法可以检测:1.TCP连接双方定时发握手消息 2.利用TCP协议栈中的KeepAlive探测

第二种方法简单可靠,只需对TCP连接两个Socket设定KeepAlive探测,

所以本文只讲第二种方法在Linux,Window2000下的实现(在其它的平台上没有作进一步的测试)

Windows 2000平台下

头文件

#include <mstcpip.h>

//定义结构及宏

struct TCP_KEEPALIVE {

u_longonoff;

u_longkeepalivetime;

u_longkeepaliveinterval;

} ;

 

  1. tcp_keepalive live,liveout;  

  2. live.keepaliveinterval=500;  

  3. live.keepalivetime=3000;  

  4. live.onoff=TRUE;  

  5. int iRet = setsockopt(Socket,SOL_SOCKET,SO_KEEPALIVE,(char *)Opt,sizeof(int));  

  6. if(iRet == 0){  

  7.   

  8.         DWORD dw;  

  9.   

 10.         if(WSAIoctl(Socket,SIO_KEEPALIVE_VALS,&live,sizeof(live),&liveout,sizeof(liveout),&dw,NULL,NULL)== SOCKET_ERROR){  

 11.   

 12.                 //Delete Client  

 13.   

 14.                 return;  

 15.         }  

 16.    }  

  

 ACE下代码 //by rainfish    blog.csdn.net/bat603

  

  int Opt = 1;

  //在测试过程中，发现检测的次数是5次，即下面的设置中，从最近一次消息开始计算的10秒后，每次间隔5秒，连续发送5次，即

  //35秒发现网络断了

tcp_keepalive live,liveout;  

live.keepaliveinterval=5000; //每次检测的间隔 （单位毫秒）

live.keepalivetime=10000;  //第一次开始发送的时间（单位毫秒）

live.onoff=TRUE;  

int iRet = stream.set_option(SOL_SOCKET,SO_KEEPALIVE,&Opt,sizeof(int));  

if(iRet == 0){  

      

           DWORD dw;  

      

     //此处显示了在ACE下获取套接字的方法，即句柄的(SOCKET)化就是句柄

          if(WSAIoctl((SOCKET)h,SIO_KEEPALIVE_VALS,&live,sizeof(live),&liveout,sizeof(liveout),&dw,NULL,NULL)== SOCKET_ERROR){  

    

                  //Delete Client  

     

                  return;  

          }  

     }  

 

 

 

Linux平台下

#include    "/usr/include/linux/tcp.h"

#include "/usr/include/linux/socket.h"

////KeepAlive实现，单位秒

//下面代码要求有ACE,如果没有包含ACE,则请把用到的ACE函数改成linux相应的接口

int keepAlive = 1;//设定KeepAlive

int keepIdle = 5;//开始首次KeepAlive探测前的TCP空闭时间

int keepInterval = 5;//两次KeepAlive探测间的时间间隔

int keepCount = 3;//判定断开前的KeepAlive探测次数

 

if(setsockopt(s,SOL_SOCKET,SO_KEEPALIVE,(void*)&keepAlive,sizeof(keepAlive)) == -1)

{

ACE_DEBUG ((LM_INFO,

ACE_TEXT ("(%P|%t) setsockopt SO_KEEPALIVE error!/n")));

 

}

 

if(setsockopt(s,SOL_TCP,TCP_KEEPIDLE,(void *)&keepIdle,sizeof(keepIdle)) == -1)

{

ACE_DEBUG ((LM_INFO,

ACE_TEXT ("(%P|%t) setsockopt TCP_KEEPIDLE error!/n")));

}

 

if(setsockopt(s,SOL_TCP,TCP_KEEPINTVL,(void *)&keepInterval,sizeof(keepInterval)) == -1)

{

ACE_DEBUG ((LM_INFO,

ACE_TEXT ("(%P|%t) setsockopt TCP_KEEPINTVL error!/n")));

}

 

if(setsockopt(s,SOL_TCP,TCP_KEEPCNT,(void *)&keepCount,sizeof(keepCount)) == -1)

{

ACE_DEBUG ((LM_INFO,

ACE_TEXT ("(%P|%t)setsockopt TCP_KEEPCNT error!/n")));

}