www.pudn.com > DataGram.zip > dserver.cpp

// 
// DServer.cpp 
// 
// Extremely simple, totally useless datagram server example. 
// Works in conjunction with DClient.cpp. 
// 
// The program sets itself up as a server using the UDP 
// protoocl. It waits for data from a client, displays 
// the incoming data, sends a message back to the client 
// and then exits. 
// 
// Compile and link with wsock32.lib 
// 
// Pass the port number that the server should bind() to 
// on the command line. Any port number not already in use 
// can be specified. 
// 
// Example: DServer 2000 
// 
 
#include  
#include  
 
// Function prototype 
void DatagramServer(short nPort); 
 
// Helper macro for displaying errors 
#define PRINTERROR(s)	\ 
		fprintf(stderr,"\n%: %d\n", s, WSAGetLastError()) 
 
//////////////////////////////////////////////////////////// 
 
void main(int argc, char **argv) 
{ 
	WORD wVersionRequested = MAKEWORD(1,1); 
	WSADATA wsaData; 
	int nRet; 
	short nPort; 
 
	// 
	// Check for port argument 
	// 
	if (argc != 2) 
	{ 
		fprintf(stderr,"\nSyntax: dserver PortNumber\n"); 
		return; 
	} 
 
	nPort = atoi(argv[1]); 
	 
	// 
	// Initialize WinSock and check version 
	// 
	nRet = WSAStartup(wVersionRequested, &wsaData); 
	if (wsaData.wVersion != wVersionRequested) 
	{	 
		fprintf(stderr,"\n Wrong version\n"); 
		return; 
	} 
 
	// 
	// Do all the stuff a datagram server does 
	// 
	DatagramServer(nPort); 
	 
	// 
	// Release WinSock 
	// 
	WSACleanup(); 
} 
 
//////////////////////////////////////////////////////////// 
 
void DatagramServer(short nPort) 
{ 
	// 
	// Create a UDP/IP datagram socket 
	// 
	SOCKET theSocket; 
 
	theSocket = socket(AF_INET,		// Address family 
					   SOCK_DGRAM,  // Socket type 
					   IPPROTO_UDP);// Protocol 
	if (theSocket == INVALID_SOCKET) 
	{ 
		PRINTERROR("socket()"); 
		return; 
	} 
 
	 
	// 
	// Fill in the address structure 
	// 
	SOCKADDR_IN saServer; 
 
	saServer.sin_family = AF_INET; 
	saServer.sin_addr.s_addr = INADDR_ANY; // Let WinSock assign address 
	saServer.sin_port = htons(nPort);	   // Use port passed from user 
 
 
	// 
	// bind the name to the socket 
	// 
	int nRet; 
 
	nRet = bind(theSocket,				// Socket descriptor 
				(LPSOCKADDR)&saServer,  // Address to bind to 
				sizeof(struct sockaddr)	// Size of address 
				); 
	if (nRet == SOCKET_ERROR) 
	{ 
		PRINTERROR("bind()"); 
		closesocket(theSocket); 
		return; 
	} 
 
 
	// 
	// This isn't normally done or required, but in this  
	// example we're printing out where the server is waiting 
	// so that you can connect the example client. 
	// 
	int nLen; 
	nLen = sizeof(SOCKADDR); 
	char szBuf[256]; 
 
	nRet = gethostname(szBuf, sizeof(szBuf)); 
	if (nRet == SOCKET_ERROR) 
	{ 
		PRINTERROR("gethostname()"); 
		closesocket(theSocket); 
		return; 
	} 
 
	// 
	// Show the server name and port number 
	// 
	printf("\nServer named %s waiting on port %d\n", 
			szBuf, nPort); 
			 
 
	// 
	// Wait for data from the client 
	// 
	SOCKADDR_IN saClient; 
 
	memset(szBuf, 0, sizeof(szBuf)); 
	nRet = recvfrom(theSocket,				// Bound socket 
					szBuf,					// Receive buffer 
					sizeof(szBuf),			// Size of buffer in bytes 
					0,						// Flags 
					(LPSOCKADDR)&saClient,	// Buffer to receive client address  
					&nLen);					// Length of client address buffer 
 
	// 
	// Show that we've received some data 
	// 
	printf("\nData received: %s", szBuf); 
 
 
	// 
	// Send data back to the client 
	// 
	strcpy(szBuf, "From the Server"); 
	sendto(theSocket,						// Bound socket 
		   szBuf,							// Send buffer 
		   strlen(szBuf),					// Length of data to be sent 
		   0,								// Flags 
		   (LPSOCKADDR)&saClient,			// Address to send data to 
		   nLen);							// Length of address 
 
	// 
	// Normally a server continues to run so that 
	// it is available to other clients. In this 
	// example, we exit as soon as one transaction 
	// has taken place. 
	// 
	closesocket(theSocket); 
	return; 
}