void do_client_work(int client_sock,struct sockaddr_in client)
{
unsigned char cmd;
int val;
char *VideoPtr;
send_client_info(client_sock,"hello",5);
TCP_VIDEO_AGAIN_FLAG = 1;
printf("\nrecv start ...\n");
while(1)
{
fd_set rds;
struct timeval step;
int ret;
FD_ZERO(&rds);
FD_SET(client_sock,&rds);
step.tv_sec = 0;
step.tv_usec = 1000;
ret = select(client_sock+1,&rds,NULL,NULL,&step);
if(ret < 0)
{
perror("select");
exit(-1);
}
if(ret == 0)
{
...//执行等待超时命令
}
else if(FD_ISSET(client_sock,&rds))
{
val = recv_client_info(client_sock,&cmd,1);
if(val < 0)
{
break;
}
else
{
...//执行读写客户端数据操作
if(TcpOutFlag==1)
{
TcpOutFlag=0;
break;
}
}
}
}
}
//TCP接收数据
int recv_client_info(int client_sock,char* info,int length)
{
int num;
struct timeval tv;
tv.tv_sec = 15;
tv.tv_usec = 0;
if (setsockopt(client_sock, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv))>=0)
{
num = recv(client_sock,info,length,MSG_NOSIGNAL);
if(num < 0)
{
perror("recv");
return 0;
}
else if(num == 0)
{
printf("recv over\n");
return -2;
}
else
{
pthread_mutex_lock(&mutex);
TCP_Timeout = 0;
pthread_mutex_unlock(&mutex);
return 0;
}
}
else
{
printf("TCP CONNECT超时...\n");
return -1;
}
}
第二种方法在Linux,Window2000下的实现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
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")));
}
假设一种情况：一个socket TCP监听进程监听数据的时候如何接收关闭文件的socket连接？
不用并发
read/recv函数返回0均表示正常结束。此时关闭即可。如果用select/poll/epoll管理，该套接字也会读就绪，然后调用recv/read返回0。
对于异常关闭如网络崩溃、主机宕机等，可通过设置SO_KEEPALIVE设置保活，协议会按照设定间隔自动发送探测分节。该选项分为设置无数据首次探测时间、探测间隔、探测次数控制TCP是否出错。如果你设置首次探测在10秒之后、探测间隔3次，探测次数3次，则最多30秒之后将给应用层返回一个对方非正常关闭的异常，此时可通过获得errno得到对应错误，read/recv返回为-1。具体代码是：
void setKeepAlive( int iSockfd , socklen_t iIdleTime , socklen_t iInterval , socklen_t iCount )
{
setsockopt( iSockfd , SOL_SOCKET , SO_KEEPALIVE , (const char*)&iSockAttrOn , sizeof(iSockAttrOn) );
setsockopt( iSockfd , SOL_TCP , TCP_KEEPIDLE , (const char*)&iIdleTime , sizeof(iIdleTime) );
setsockopt( iSockfd , SOL_TCP , TCP_KEEPINTVL , (const char*)&iInterval,sizeof(iInterval) );
setsockopt( iSockfd , SOL_TCP , TCP_KEEPCNT , (const char*)&iCount,sizeof(iCount) );
}
