可以在使用C语言实现Socket编程的两台计算机之间转移数据。
在相同情况下，可以使用用户数据报协议(UDP)和简单的客户端/服务器轻松地发送文件。
安全性-通过加密处理。
协议-UDP
加密-XOR加密
服务器启动并等待文件名。
客户端发送文件名。
服务器接收到该文件名。如果存在文件，则服务器开始读取文件，并继续发送一个缓冲区，该缓冲区填充有加密的文件内容，直到达到文件末尾为止。
文件尾标有EOF标记。
直到（除非）收到EOF为止，文件都作为缓冲区被接收。之后，将其加密。
如果文件不存在，则会发送一条消息“找不到文件”。
// server code for UDP socket programming
#include <arpa/inet.h>
#include <netinet/in.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <unistd.h>
#define IP_Protocol 0
#define Port_No 15050
#define Net_Buf_Size 32
#define CipherKey 'S'
#define发送RecvFlag 0
#define NoFile "文件未找到！"
//清除缓冲区功能
void clearBuf(char* b1){
int i;
for (i = 0; i < Net_Buf_Size; i++)
b1[i] = '\0';
}
//加密方法功能
char Cipher(char ch1){
return ch1 ^ CipherKey;
}
//发送文件功能
int发送File(FILE* fp1, char* buf1, int s1){
int i, len;
if (fp1 == NULL) {
strcpy(buf1, NoFile);
len = strlen(NoFile);
buf1[len] = EOF;
for (i = 0; i <= len; i++)
buf1[i] = Cipher(buf1[i]);
return 1;
}
char ch1, ch2;
for (i = 0; i < s1; i++) {
ch1= fgetc(fp);
ch2 = Cipher(ch1);
buf1[i] = ch2;
if (ch1 == EOF)
return 1;
}
return 0;
}
//驱动程式码
int main(){
int sockfd1, nBytes;
struct sockaddr_in addr_con;
int addrlen = sizeof(addr_con);
addr_con.sin_family = AF_INET;
addr_con.sin_port = htons(Port_No);
addr_con.sin_addr.s_addr = INADDR_ANY;
char net_buf1[Net_Buf_Size];
FILE* fp1;
// socket() sockfd1 = socket(AF_INET, SOCK_DGRAM, IP_Protocol);
if (sockfd1 < 0)
printf("\nfile descriptor is not接收d!!\n");
else
printf("\nfile descriptor %d is接收d\n", sockfd1);
// bind() if (bind(sockfd1, (struct sockaddr*)&addr_con,
sizeof(addr_con)) == 0)
printf("\nSuccessfully is binded!\n");
else
printf("\nBinding is Failed!\n");
while (1) {
printf("\nWaiting for name of file...\n");
//接收文件名
clearBuf(net_buf1);
nBytes = recvfrom(sockfd1, net_buf1,
Net_Buf_Size,发送RecvFlag,
(struct sockaddr*)&addr_con,
&addrlen);
fp1 = fopen(net_buf1, "r");
printf("\nFile Name is接收d: %s\n", net_buf1);
if (fp1 == NULL)
printf("\nFile open is failed!\n");
else
printf("\nFile Successfully is opened!\n");
while (1) {
//处理
if (sendFile(fp1, net_buf1, Net_Buf_Size)) {
发送to(sockfd1, net_buf1, Net_Buf_Size,
发送RecvFlag,
(struct sockaddr*)&addr_con,
addrlen);
break;
}
//发送
发送to(sockfd1, net_buf1, Net_Buf_Size,
发送RecvFlag,
(struct sockaddr*)&addr_con, addrlen);
clearBuf(net_buf1);
}
if (fp1 != NULL)
fclose(fp1);
}
return 0;
}// client code for UDP socket programming
#include <arpa/inet.h>
#include <netinet/in.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <unistd.h>
#define IP_Protocol 0
#define IP_Address "127.0.0.1" // localhost
#define Port_No 15050
#define Net_Buf_Size 32
#define CipherKey 'S'
#define发送RecvFlag 0
//清除缓冲区功能
void clearBuf(char* b1){
int i;
for (i = 0; i < Net_Buf_Size; i++)
b1[i] = '\0';
}
//解密方法功能
char Cipher(char ch1){
return ch1 ^ CipherKey;
}
//接收文件功能
int recvFile(char* buf1, int s1)
{
int i;
char ch1;
for (i = 0; i < s1; i++) {
ch1 = buf1[i];
ch1 = Cipher(ch1);
if (ch1 == EOF)
return 1;
else
printf("%c", ch1);
}
return 0;
}
//驱动程式码
int main(){
int sockfd1, nBytes;
struct sockaddr_in addr_con;
int addrlen = sizeof(addr_con);
addr_con.sin_family = AF_INET;
addr_con.sin_port = htons(Port_No);
addr_con.sin_addr.s_addr = inet_addr(IP_Address);
char net_buf1[Net_Buf_Size];
FILE* fp1;
// socket() sockfd1 = socket(AF_INET, SOCK_DGRAM,
IP_Protocol);
if (sockfd1 < 0)
printf("\nfile descriptor is not接收d!!\n");
else
printf("\nfile descriptor %d is接收d\n", sockfd1);
while (1) {
printf("\nPlease enter the name of file to接收:\n");
scanf("%s", net_buf1);
发送to(sockfd1, net_buf1, Net_Buf_Size,
发送RecvFlag, (struct sockaddr*)&addr_con,
addrlen);
printf("\n---------Data is接收d---------\n");
while (1) {
//接收
clearBuf(net_buf1);
nBytes = recvfrom(sockfd1, net_buf1, Net_Buf_Size,
发送RecvFlag, (struct
sockaddr*)&addr_con,
&addrlen);
//处理
if (recvFile(net_buf1, Net_Buf_Size)) {
break;
}
}
printf("\n-------------------------------\n");
}
return 0;
}