Winsocket 多線程之單服務器多客戶端

本文內容來自 http://www.rohitab.com/discuss/topic/26991-cc-how-to-code-a-multi-client-server-in-c-using-threads/

服務器

#include <windows.h>
#include <stdlib.h>
#include <stdio.h>
#include <winsock.h>

/* our thread for recving commands */
DWORD WINAPI receive_cmds( LPVOID lpParam )
{
	printf( "thread created\r\n" );

	/* set our socket to the socket passed in as a parameter */
	SOCKET current_client = (SOCKET) lpParam;

	/* buffer to hold our recived data */
	char buf[100];
	/* buffer to hold our sent data */
	char sendData[100];
	/* for error checking */
	int res;

	/* our recv loop */
	while ( true )
	{
		res = recv( current_client, buf, sizeof(buf), 0 ); /* recv cmds */

		Sleep( 10 );

		if ( res == 0 )
		{
			MessageBox( 0, "error", "error", MB_OK );
			closesocket( current_client );
			ExitThread( 0 );
		}

		if ( strstr( buf, "hello" ) )           /* greet this user */
		{
			printf( "\nrecived hello cmd" );

			strcpy( sendData, "hello, greetz from KOrUPt\n" );
			Sleep( 10 );
			send( current_client, sendData, sizeof(sendData), 0 );
		} 
		else if ( strstr( buf, "bye" ) )      /* dissconnected this user */
		{
			printf( "\nrecived bye cmd\n" );

			strcpy( sendData, "cya\n" );
			Sleep( 10 );
			send( current_client, sendData, sizeof(sendData), 0 );

			/* close the socket associted with this client and end this thread */
			closesocket( current_client );
			ExitThread( 0 );
		} 
		else 
		{
			strcpy( sendData, "Invalid cmd\n" );
			Sleep( 10 );
			send( current_client, sendData, sizeof(sendData), 0 );
		}

		/* clear buffers */
		strcpy( sendData, "" );
		strcpy( buf, "" );
	}
}


int main()
{
	printf( "Starting up multi-threaded TCP server by KOrUPt\r\n" );

	/* our masterSocket(socket that listens for connections) */
	SOCKET sock;

	/* for our thread */
	DWORD thread;

	WSADATA		wsaData;
	sockaddr_in	server;

	/* start winsock */
	int ret = WSAStartup( 0x101, &wsaData ); /* use highest version of winsock avalible */

	if ( ret != 0 )
	{
		return(0);
	}

	/* fill in winsock struct ... */
	server.sin_family	= AF_INET;
	server.sin_addr.s_addr	= INADDR_ANY;
	server.sin_port		= htons( 123 ); /* listen on telnet port 23 */

	/* create our socket */
	sock = socket( AF_INET, SOCK_STREAM, 0 );

	if ( sock == INVALID_SOCKET )
	{
		return(0);
	}

	/* bind our socket to a port(port 123) */
	if ( bind( sock, (sockaddr *) &server, sizeof(server) ) != 0 )
	{
		return(0);
	}

	/* listen for a connection */
	if ( listen( sock, 5 ) != 0 )
	{
		return(0);
	}

	/* socket that we snedzrecv data on */
	SOCKET client;

	sockaddr_in	from;
	int		fromlen = sizeof(from);

	/* loop forever */
	while ( true )
	{
		/* accept connections */
		client = accept( sock, (struct sockaddr *) &from, &fromlen );
		printf( "Client connected\r\n" );

		/* create our recv_cmds thread and parse client socket as a parameter */
		CreateThread( NULL, 0, receive_cmds, (LPVOID) client, 0, &thread );
	}

	/* shutdown winsock */
	closesocket( sock );
	WSACleanup();

	/* exit */
	return(0);
}

客戶端

#include <windows.h>
#include <winsock.h>
#include <stdio.h>
#include <iostream>
#include <conio.h>
#include <signal.h>
#include <stdio.h>

/*
 * DECLARATIONS
 * error trapping signals
 */
#define SIGINT	2
#define SIGKILL 9
#define SIGQUIT 3
/* SOCKETS */
SOCKET sock, client;

void s_handle( int s )
{
	if ( sock )
		closesocket( sock );
	if ( client )
		closesocket( client );
	WSACleanup();
	Sleep( 1000 );
	std::cout << "EXIT SIGNAL :" << s;
	exit( 0 );
}

void s_cl( char *a, int x )
{
	std::cout << a;
	s_handle( x + 1000 );
}

int main()
{
	HANDLE hStdout = GetStdHandle( STD_OUTPUT_HANDLE );
	SetConsoleTextAttribute( hStdout, FOREGROUND_GREEN | FOREGROUND_INTENSITY );
	SetConsoleTitle( ".:: Basic Echo Client By KOrUPt 07 ::. " );

	/* Declarations */
	DWORD	poll;
	int	res, i = 1, port = 999;
	char	buf[100];
	char	msg[100] = "";
	char	ip[15];
	WSADATA data;

	signal( SIGINT, s_handle );
	signal( SIGKILL, s_handle );
	signal( SIGQUIT, s_handle );

	std::cout << "\t\tEcho Client by KOrUPt";

	std::cout << "\n\n\n\t\tEnter IP to connect to: ";
	gets( ip );

	sockaddr_in	ser;
	sockaddr	addr;

	ser.sin_family		= AF_INET;
	ser.sin_port		= htons( 123 );         /* Set the port */
	ser.sin_addr.s_addr	= inet_addr( ip );      /* Set the address we want to connect to */

	memcpy( &addr, &ser, sizeof(SOCKADDR_IN) );

	res = WSAStartup( MAKEWORD( 1, 1 ), &data );    /* Start Winsock */
	std::cout	<< "\n\nWSAStartup"
			<< "\nVersion: " << data.wVersion
			<< "\nDescription: " << data.szDescription
			<< "\nStatus: " << data.szSystemStatus << std::endl;

	if ( res != 0 )
		s_cl( "WSAStarup failed", WSAGetLastError() );

	sock = socket( AF_INET, SOCK_STREAM, IPPROTO_TCP ); /* Create the socket */
	if ( sock == INVALID_SOCKET )
		s_cl( "Invalid Socket ", WSAGetLastError() );
	else if ( sock == SOCKET_ERROR )
		s_cl( "Socket Error)", WSAGetLastError() );
	else
		std::cout << "Socket Established" << std::endl;

	res = connect( sock, &addr, sizeof(addr) );     /* Connect to the server */
	if ( res != 0 )
	{
		s_cl( "SERVER UNAVAILABLE", res );
	} 
	else 
	{
		std::cout << "\nConnected to Server: ";
		memcpy( &ser, &addr, sizeof(SOCKADDR) );
	}

	char	RecvdData[100] = "";
	int	ret;

	while ( true )
	{
		strcpy( buf, "" );
		std::cout << "\nEnter message to send ->\n";
		fgets( buf, sizeof(buf), stdin );

		Sleep( 5 );
		res = send( sock, buf, sizeof(buf), 0 );

		if ( res == 0 )
		{
			/* 0==other side terminated conn */
			printf( "\nSERVER terminated connection\n" );
			Sleep( 40 );
			closesocket( client );
			client = 0;
			break;
		} 
		else if ( res == SOCKET_ERROR )
		{
			/* -1 == send error */
			printf( "Socket error\n" );
			Sleep( 40 );
			s_handle( res );
			break;
		}

		ret = recv( sock, RecvdData, sizeof(RecvdData), 0 );
		if ( ret > 0 )
		{
			std::cout << std::endl << RecvdData;
			strcpy( RecvdData, "" );
		}
	}

	closesocket( client );
	WSACleanup();
}

說明

原文是從單線程說的，感興趣可以去看一下。

關於客戶端發送消息，發送 hello 時服務器會正常回復，發送 bye 會斷開連接，發送其他的服務器都只會回覆 Invalid cmd ，具體看服務器的 receive_cmds 函數。

關鍵的地方就在服務器端使用的多線程：

	/* loop forever */
	while ( true )
	{
		/* accept connections */
		client = accept( sock, (struct sockaddr *) &from, &fromlen );
		printf( "Client connected\r\n" );

		/* create our recv_cmds thread and parse client socket as a parameter */
		CreateThread( NULL, 0, receive_cmds, (LPVOID) client, 0, &thread );
	}

TODO

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