多线程connect问题

2011-12-14 03:34:03 172 阅读 AI 写同款 · GEO 优化AI 选题数据监测一键分发 ›

非阻塞connect卡select问题分析非阻塞connect卡select问题分析目录非阻塞connect卡select问题分析一、connect原理 1.1阻塞与非阻塞connect的区别 1.2 connect函数超时时间二、select原理三、问题原因 4.1 select的第四个参数建议加上。 4.2 select的第五个参数timeout的大小建议。 4.3 fd的多线程操作一、connect原理 1.1阻塞与非阻塞connect的区别为解决阻塞connect等待耗时过长，最长等待127秒问题，企阅读详情

最近做测试发现了这样一个问题，创建20条线程去不断连接服务端，其中只有一个IP地址是存在的，问题来了，如果值创建一条线程来连接存在的IP，那是没有问题的，但是创建了20条线程后，存在的那个IP connect也连接失败，这是为什么呢？
（我这边在192.168.1.22的机子上有一个服务端）

//main.c

#include <winsock2.h>

#include <stdio.h>

#include <process.h>



#include <errno.h>

#pragma comment(lib,"ws2_32.lib")



#include <stdlib.h>

#include <string.h>



#define PORT 80



int InitSock(void)

{

	int err = 0;

	WORD wVersionRequested;

	WSADATA wsaData;

    

	wVersionRequested = MAKEWORD( 2, 2 );

	

	err = WSAStartup(wVersionRequested, &wsaData);

	if ( err != 0 ) 

	{

		return -1;

	}

	if ( LOBYTE( wsaData.wVersion ) != 2 ||

		HIBYTE( wsaData.wVersion ) != 2 ) 

	{

		WSACleanup();

		return -1; 

	}

	

	return 0;

}



int Hi_Setup_OpenTcp(struct sockaddr *SockAddr, int NameLen, int nTimeout)

{

	int f = -1;

	struct timeval tv;

	fd_set writefds;

	int len, error, s32Ret;

    unsigned long non_blocking = 1;

    unsigned long blocking = 0;

	unsigned long reuse = 1;



    if ((f = socket(AF_INET, SOCK_STREAM, 0)) < 0)

    {

        return -1;

    }



    tv.tv_sec = nTimeout / 1000;

    tv.tv_usec = nTimeout % 1000;



	ioctlsocket(f, FIONBIO, &non_blocking);



	s32Ret = connect(f, SockAddr, NameLen);

	if (s32Ret < 0)

	{

		FD_ZERO(&writefds); 

		FD_SET((unsigned int)f, &writefds);

		if(select(f+1, NULL, &writefds, NULL, &tv) != 0)

		{ 

            if(FD_ISSET(f, &writefds))

			{

                len = sizeof(error); 

                //下面的一句一定要，主要针对防火墙 

                if(getsockopt(f, SOL_SOCKET, SO_ERROR, (char *)&error, &len) < 0)

                    goto error_ret; 

                if(error != 0) 

                    goto error_ret; 

            }

            else

                goto error_ret; //timeout or error happen 

        }

        else 

			goto error_ret;



		ioctlsocket(f, FIONBIO, &blocking);

	}

    else

	{

error_ret:

		closesocket(f);

		return -1;

    }

	

	return f;

}



/******************************************

 * connect server

 ******************************************/

int HI_Setup_Connect(const char* pServer, int nPort, int nTimeout, 

                                       int *pSessSock)

{

    int GetHost = -1;

    struct sockaddr_in SockAddr;

	unsigned int net_addr = 0;

	struct hostent *Hostent = NULL;



    Hostent = gethostbyname(pServer);

    if (NULL != Hostent)

    {

        GetHost = 0;

    }

    else

    {

        net_addr = inet_addr(pServer);

        if(INADDR_NONE == net_addr)

        {

            GetHost = -1;

        }

        else

        {

            Hostent = gethostbyaddr((const char*) &net_addr, sizeof(unsigned int), PF_INET);

            if (Hostent)

            {

                GetHost = 0;

            }

        }

    }

    

    if (0 == GetHost)

    {

        SockAddr.sin_family = AF_INET;

        SockAddr.sin_addr.s_addr = *(unsigned int *) Hostent->h_addr;

        SockAddr.sin_port = htons(PORT);

        *pSessSock =  Hi_Setup_OpenTcp((struct sockaddr *) & SockAddr, 

                           sizeof(SockAddr), nTimeout);

            

		//if(strcmp(pServer, "192.168.1.22") == 0)

		//	printf("%s\n", pServer);

        if (*pSessSock < 0)

        {

            GetHost = -1;

        }

    }

    return GetHost;



}



char sHost[20][32] = {"192.168.1.22", "192.168.1.200", 

						"192.168.1.201", "192.168.1.202", 

						"192.168.1.203", "192.168.1.204", 

						"192.168.1.205", "192.168.1.206", 

						"192.168.1.207", "192.168.1.208",

						"192.168.1.209", "192.168.1.210", 

						"192.168.1.211", "192.168.1.212", 

						"192.168.1.213", "192.168.1.214", 

						"192.168.1.215", "192.168.1.216", 

						"192.168.1.217", "192.168.1.218"};



int ConnectPross(int index)

{

	printf("%s\n", sHost[index]);

	while(1)

	{

		int nSock = -1;

		int ret = HI_Setup_Connect(sHost[index], PORT, 5000, &nSock);

		if(ret == -1)

		{

			if(index == 0)

			{

				printf("connect Fail:%s\n", sHost[index]);

			}

		}

		else

		{

			closesocket(nSock);

			if(index == 0)

			{

				printf("connected\n");

			}

		}



		Sleep(5000);

	}

	return 0;

}



DWORD WINAPI ConnectThreadPross(LPVOID lpParameter)

{

	int index = (int)lpParameter;

	ConnectPross(index);

	return 0;

}



int main(int argc, char* argv[])

{

	int i = 0;

	DWORD dwThreadID = 0;

	HANDLE hThread = NULL;



	InitSock();

	for(i=0; i<20; i++)

	{

		dwThreadID = 0;

		hThread = CreateThread(NULL, 0, ConnectThreadPross, (LPVOID)i, 0, &dwThreadID);

		CloseHandle(hThread);

		Sleep(10);

	}



	while(1)

	{

		Sleep(1000);

	}



	WSACleanup();

	return 0;

}