client.c

udp通信阿达洒洒萨法萨达洒洒洒洒嗒嗒嗒萨

#include "client.h"

void main()
{
	clientInit();
	client();
	closesocket( localSkt );
}

void clientInit()
{
	struct sockaddr_in clientAddr;
	struct hostent far *host;
	struct in_addr     *ip;
	
	char               serverIP[20];
	char               name[40];
	unsigned long      lRemIP;
	
	char               showSvr[20];
	char               showClt[20];

	WSADATA wsaData;
	WSAStartup( WINSOCK_VERSION , &wsaData ) ;
	localSkt = socket( AF_INET , SOCK_DGRAM , 0 );
	
	/*get local IP address*/
	gethostname( name , sizeof(name) ) ;
	host = gethostbyname( name ) ;
	ip = (struct in_addr*)*host->h_addr_list ;
	
	/*bind local IP address to localSkt*/
	clientAddr.sin_addr   = *ip;
	clientAddr.sin_family = AF_INET;
	clientAddr.sin_port   = htons( LOCAL_PORT );
	/*can NOT bind*/
	/*get server IP*/
	
	printf( "Please enter the server IP:" );
	gets( serverIP );
	if ( strlen( serverIP ) )
		lRemIP = inet_addr( serverIP );
	else
		lRemIP = inet_addr(SERVER_IP);
	serverAddr.sin_addr.S_un.S_addr = lRemIP;
	serverAddr.sin_family = AF_INET;
	serverAddr.sin_port = htons(SERVER_PORT);
	
	strcpy( showSvr,inet_ntoa(serverAddr.sin_addr) );
	printf( "Server IP: %s    " , inet_ntoa( serverAddr.sin_addr ));
	strcpy( showClt,inet_ntoa(clientAddr.sin_addr) );
	printf( "Local IP:%s\n" ,inet_ntoa(clientAddr.sin_addr) );
	printf( "Client Initiate Successfully\nBegin to communicate:\n" ) ;
	printf( "*************************************************************\n" ) ;
}

void client()
{
	int       isFirstPkt = 0;
	int       flagResend = 0;
	int       bfsz       = MSG_MAX_SIZE;
	int       totalSize  = 0;				/*the size of the file to be send*/
	short int seqNum     = 0;
	int       location   = 0;
	unsigned char msg[MSG_MAX_SIZE];
	unsigned char packet[MSG_MAX_SIZE+PKT_CHECKSUM_SIZE+PKT_SEQNUM_SIZE+PKT_MSG_SIZE];
	
	unsigned char recvMsg[MSG_MAX_SIZE];
	unsigned char recvPacket[MSG_MAX_SIZE+PKT_CHECKSUM_SIZE+PKT_SEQNUM_SIZE+PKT_MSG_SIZE];
	int       msgLen;
	int       addrSize = sizeof(serverAddr);
	
	int       res;
	fd_set    readSet;
	struct timeval tv;
	char      name[NAME_SIZE];

	printf( "Please enter the file name:" );
	gets( name );
	fSrc = fopen( name,"rb" );
	totalSize = getFileSize( fSrc );
	while ( location != totalSize &&bfsz != 0 )
	{
		if ( flagResend == 0 )/*if send new data*/
		{
			/*read data from file*/
			memset( msg,0,sizeof(msg) );
			memset( packet,0,sizeof(packet) );
			if ( isFirstPkt == 0 )/*prepare the first packet*/
			{
				_32to8( msg,totalSize );
				packageMsg( packet,msg,0,seqNum );
			}
			else
			{
				memset( msg,0,sizeof(msg) );
				if ( fread( msg,1,bfsz,fSrc ) )
				{
					location += bfsz;
					packageMsg( packet,msg,bfsz,seqNum );
				}
				else
				{
					fseek( fSrc,location,0 );
					bfsz = bfsz/2;
					continue;
				}
			}
			
		}
		else
			printf( "Msg Resend--" );
		printf( "SeqNum  %d \n %s\n",seqNum,msg );
		if ( sendto( localSkt,packet,sizeof(packet),0,(struct sockaddr*)&serverAddr,
			sizeof(serverAddr) ) 
			== SOCKET_ERROR)
			printf( "Send Error----%d\n",WSAGetLastError() );
		else
			printf( "%d************************************************Message SendOut\n",location );
		
		/*wait for ACK*/
		memset( recvPacket,0,sizeof(recvPacket) );
		memset( recvMsg,0,sizeof(recvMsg) );
		while (1)
		{		
			tv.tv_sec  = 11;
			tv.tv_usec = 0;
			FD_ZERO(&readSet);
			FD_SET(localSkt, &readSet);
			
			res = select(localSkt+1, &readSet, NULL, NULL, &tv);
			if(res == SOCKET_ERROR)
			{
				printf("Socket Error on selecting!\n");
				break;
			}
			if(res == 0)	//timeout
			{
				printf("Request timed out.\n");
				flagResend = 1;
				break;
			}
			if(FD_ISSET(localSkt, &readSet))
			{
				msgLen = recvfrom( localSkt,recvPacket,sizeof(recvPacket),0,
					(struct sockaddr*)&serverAddr,&addrSize );
				if ( msgLen > 0 && !checkError( recvPacket ) )
				{
					flagResend = 0;
					disPacketMsg( recvMsg,recvPacket );
					printf( "Receive from %s:\n %d  %s\n",inet_ntoa( serverAddr.sin_addr ),
						getSeqNum(recvPacket),recvMsg );
					printf( "*************************************************************\n" );
					if ( getSeqNum(recvPacket) == seqNum )
					{
						if ( isFirstPkt == 0 ) 
							isFirstPkt = 1;
						seqNum = (seqNum+1)%SPACE_NUM;
						break;
					}
				}	
				flagResend = 1;
				break;
			}
		}
	}
}	

int getFileSize(FILE *fSrc)
{
	int  size = 0;
	int  bfsz = MSG_MAX_SIZE;
	char temp[MSG_MAX_SIZE];
	while ( bfsz != 0 )
	{
		memset( temp,0,sizeof(temp) );
		if ( fread( temp,1,bfsz,fSrc ) )
		{
			size += bfsz;
		}
		else
		{
			fseek( fSrc,size,0 );
			bfsz = bfsz/2;
		}
	}
	fseek( fSrc,0,0 );
	return size;
}

void _32to8(unsigned char* buffer,int size)
{
	int i=0;
	while ( i<4 )
	{
		buffer[i] = (size>>(32-(i+1)*8))&0x00ff;
		i++;
	}
}

int _8to32(unsigned char *buffer)
{
	return ((buffer[0]*0x1000000)&0xff000000)+((buffer[1]*0x10000)&0xff0000)
		+((buffer[2]*0x100)&0xff00)+buffer[3];
}

void packageMsg(unsigned char *dstMsg,unsigned char *msg,int msgSize,int seqNum )
{
	unsigned int sum   = 0;
	unsigned int hWord = 0;
	int          i     = 0;
	unsigned char temp[4];
	unsigned char seq[2];
	
	for ( i=0;i<MSG_MAX_SIZE;i++ )
	{
		dstMsg[PKT_CHECKSUM_SIZE+PKT_SEQNUM_SIZE+PKT_MSG_SIZE+i] = msg[i];
	}
	
	_16to8( seq,seqNum );
	dstMsg[2] = seq[0];
	dstMsg[3] = seq[1];

	_32to8( temp,msgSize );
	dstMsg[4] = temp[0];
	dstMsg[5] = temp[1];
	dstMsg[6] = temp[2];
	dstMsg[7] = temp[3];

	i = 0;
	while ( i < MSG_MAX_SIZE+PKT_CHECKSUM_SIZE+PKT_SEQNUM_SIZE+PKT_MSG_SIZE )
	{
		sum += dstMsg[i]*0x100+dstMsg[i+1];
		i = i + 2;
	}
	hWord = (sum>>16)&0x0000ffff;
	sum   = sum &0x0000ffff;
	sum   = sum + hWord;
	sum   = ~sum;
	
	_32to8( temp,sum );
	dstMsg[0] = temp[2];
	dstMsg[1] = temp[3];
}

int  disPacketMsg( unsigned char *dstMsg,unsigned char *srcMsg )
{
	int i;
	unsigned char temp[4];
	for ( i = 0;i < MSG_MAX_SIZE;i ++ )
	{
		dstMsg[i] = srcMsg[PKT_CHECKSUM_SIZE+PKT_SEQNUM_SIZE+PKT_MSG_SIZE+i];
	}
	temp[0] = srcMsg[4];
	temp[1] = srcMsg[5];
	temp[2] = srcMsg[6];
	temp[3] = srcMsg[7];
	return _8to32( temp );
}
int  checkError( unsigned char* msg )
{
	unsigned int sum  = 0;
	unsigned int hWord = 0;
	int          i     = 0;
	
	while ( i < PKT_CHECKSUM_SIZE+PKT_SEQNUM_SIZE+MSG_MAX_SIZE+PKT_MSG_SIZE )
	{
		sum += ((msg[i]*0x100)&0xff00) + msg[i+1];
		i = i + 2;
	}
	hWord = (sum>>16)&0x0000ffff;
	sum   = sum &0x0000ffff;
	sum   = sum + hWord;
	return (sum^0xffff);
}

int  getSeqNum( unsigned char *pkt )
{
	return ( ((pkt[2]*0x100)&0xff00)+pkt[3] );
}

void _16to8( unsigned char *buffer,int value )
{
	buffer[0] = ((value>>8)&0xff);
	buffer[1] = value&0xff;
}