long.cpp

此文件实现ftp客户端的基本功能

#include <stdio.h>
#include <stdlib.h>
#include <winsock2.h>
#include <string.h>
#include <windows.h>
#include <process.h>
#include <winbase.h>
#pragma comment(lib,"ws2_32.lib")
#define BUFLEN 10000

int flag,nRC;
char s_ip[20];
char sendBuf[BUFLEN], recvBuf[BUFLEN];

void receive(SOCKET Sock)
{       nRC = recv(Sock, recvBuf, BUFLEN, 0);
	recvBuf[nRC] ='\0';
	printf("\n%s\n", recvBuf); 
}


void communicate(SOCKET Sock,char *info) 
{
	strcpy(sendBuf,info);
	send(Sock, sendBuf, strlen(sendBuf), 0);
	nRC = recv(Sock, recvBuf, BUFLEN, 0);
	recvBuf[nRC] ='\0';
	printf("\n%s\n", recvBuf);

}


int transfer(int digit)
{       int i, j, m, n;
        i = digit-1;
        j = 1;
        m = n = 0;
        while((recvBuf[i--] != ')'));
        while(recvBuf[i] != ',') {
		m += (recvBuf[i] - 48) * j;
		--i;
                j *= 10;
	}
	i--;
	j = 1;
	while(recvBuf[i] != ',') {
		n += (recvBuf[i] - 48) * j;
                --i;
		j *= 10;
	}
	return(n * 256 + m);
}



SOCKET createSock() 
{       SOCKET newSock;
	sockaddr_in clientAddr;
        newSock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
	if(newSock == INVALID_SOCKET) {
		printf("Client create socket error!\n");
		WSACleanup();
        return newSock;
	}
        printf("Socket create OK!\n");
	clientAddr.sin_family = AF_INET;
	clientAddr.sin_port = htons(0);
	clientAddr.sin_addr.S_un.S_addr = INADDR_ANY; 
                                  /*表示不确定地址*/
	nRC = bind(newSock,(LPSOCKADDR)&clientAddr,sizeof(clientAddr));
	if(nRC == SOCKET_ERROR) {
		printf("Socket bind error!\n");
		closesocket(newSock);
		WSACleanup();
		flag=-1;
        return newSock;
	}
        printf("Socket bind ok!\n");
	return newSock;
}

int connectServer(SOCKET newSock, int portnumber) 
{	sockaddr_in srvAddr;
        srvAddr.sin_family = AF_INET;
	srvAddr.sin_port = htons(portnumber);
             /*hton把主机字节顺序转化为网络字节顺序，用于短整形数据*/
	srvAddr.sin_addr.S_un.S_addr = inet_addr(s_ip);
        nRC = connect(newSock,(LPSOCKADDR)&srvAddr,sizeof(srvAddr));
	if(nRC == SOCKET_ERROR) {
		printf("Connect to server error!\n");
		closesocket(newSock);
		WSACleanup();
		return -1;
	}
	return 0;
}

void LIST(SOCKET clientSock) 
{       int portnumber;
	SOCKET dataSock;
        dataSock = createSock();
	if(flag == -1) return;
	communicate(clientSock,"TYPE I\r\n");
	communicate(clientSock,"PASV\r\n");
        portnumber = transfer(nRC);
	nRC = connectServer(dataSock, portnumber);
	if(nRC == -1) return;
        communicate(clientSock,"LIST -al\r\n");
        receive(dataSock);    /*文件列表*/
        receive(clientSock);  /*226 transfer complete*/
        closesocket(dataSock);
}


void CWD(SOCKET clientSock) 
{       char directory[25];
        printf("input the directory:");
	scanf("%s", directory);
	strcpy(sendBuf, "CWD ");
	strcat(sendBuf, directory);
	strcat(sendBuf, "\r\n");
        communicate(clientSock,sendBuf);
	communicate(clientSock,"PWD\r\n");
}

void CDUP(SOCKET clientSock) 
{       communicate(clientSock,"CDUP\r\n");
        communicate(clientSock,"PWD\r\n");
        LIST(clientSock);
}

void RETR(SOCKET clientSock) 
{       int portnumber;
        char fileName[25];
	SOCKET dataSock;
	FILE * fp;
        dataSock = createSock();
	if(flag == -1) return;
	communicate(clientSock,"TYPE I\r\n");
	communicate(clientSock,"PASV\r\n");   /*返回服务器端口号的信息*/
	portnumber = transfer(nRC);
	nRC = connectServer(dataSock, portnumber);
	if(nRC == -1) return;
	printf("input file's name:");
	scanf("%s", fileName);
	strcpy(sendBuf, "RETR ");
	strcat(sendBuf, fileName);
	strcat(sendBuf, "\r\n");
	communicate(clientSock,sendBuf);
        if(nRC == SOCKET_ERROR) {
		printf("recieve error!\n");
		closesocket(dataSock);
		WSACleanup();
		return;
	}
	fp = fopen(fileName, "w+b");
	if(!fp) {
	        printf("recieve file create error!\n");
                closesocket(dataSock);
		return;
	}
	fseek(fp, 0, SEEK_SET);
        while(1) 
        {       nRC = recv(dataSock, recvBuf, BUFLEN, 0);
	        if(nRC == 0){
	             fclose(fp);
	             break;
	        }else if(nRC > 0){
		     fwrite(recvBuf, sizeof(char), nRC, fp);
		 }
	}
        receive(clientSock);
        closesocket(dataSock);
}


void STOR(SOCKET clientSock) 
{       char fileName[25];
	int amount, portnumber;
	SOCKET dataSock;
	FILE * fp;
        dataSock = createSock();
	if(flag == -1) return;
        communicate(clientSock,"TYPE I\r\n");
	communicate(clientSock,"PASV\r\n");
        portnumber = transfer(nRC);
	nRC = connectServer(dataSock, portnumber);
	if(nRC == -1) return;
	printf("input file's name:");
	scanf("%s", fileName);
        strcpy(sendBuf, "STOR ");
	strcat(sendBuf, fileName);
	strcat(sendBuf, "\r\n");
	communicate(clientSock,sendBuf);
        if(nRC == SOCKET_ERROR) {
		printf("send error!\n");
		closesocket(dataSock);
		WSACleanup();
		return;
	}
	fp = fopen(fileName, "r+b");
	if(!fp) {
		printf("send file open error!\n");
		closesocket(dataSock);
		return;
	}
        fseek(fp, 0, SEEK_SET);
	while(1) 
        {       amount = fread(sendBuf, sizeof(char), BUFLEN, fp);
		nRC = send(dataSock, sendBuf, amount, 0);
		if(amount < BUFLEN) break;
        }
	closesocket(dataSock);
}


void main() 
{       WSADATA wsaData;
	int i,portnumber;
	SOCKET clientSock;
	char buf[30],s_port[5];
        printf("input server's ip address:");
        scanf("%s",s_ip);
        printf("and the portnumber:");
        scanf("%s",s_port);
	nRC = WSAStartup(0x0101,&wsaData);
	if(nRC){
		printf("Client initialize winsock error!\n");
		return; 
	}
	if(wsaData.wVersion != 0x0101){
		printf("Client winsock version error!\n");
		WSACleanup();
		return; 
	}
	printf("Client's winsock initialized!\n");
        clientSock = createSock();
	if(flag == -1) return; 
	portnumber=atoi(s_port);
        nRC = connectServer(clientSock, portnumber);
	if(nRC == -1) return; 
        /*接受服务器发来的数据(220,...ready)*/
	receive(clientSock);
        printf("input user's name:");
	scanf("%s", buf);
	strcpy(sendBuf, "USER ");
	strcat(sendBuf, buf);
	strcat(sendBuf, "\r\n");
	communicate(clientSock,sendBuf);
        printf("input password:");
	scanf("%s", buf);
	strcpy(sendBuf, "PASS ");
	strcat(sendBuf, buf);
	strcat(sendBuf, "\r\n");
	communicate(clientSock,sendBuf);
        communicate(clientSock,"PWD\r\n");   /*显示当前路径*/
        while(1) {
        printf("-------------------------------------------------\n");
		printf("1.LIST  2.CWD  3.CDUP 4.RETR  5.STOR  6.QUIT\n");
		printf("choose:");
		scanf("%d",&i);
                switch (i) {
			case 1: {
				LIST(clientSock);
				break;
			}
			case 2: {
				CWD(clientSock);
				break;
			}
                        case 3: {
                                CDUP(clientSock);
                                break;
                        }
			case 4: {
				RETR(clientSock);
				break;
			}			
			case 5: {
				STOR(clientSock);
				receive(clientSock);
				break;
			}
			case 6: {
				closesocket(clientSock);
				WSACleanup();
			        return; 
			}
		}

	}

}