使用UDP协议进行文件传输

Question

我有一个服务器和客户端代码，用于将文件从服务器传输到客户端。编译后，而不是将我的整个文件从服务器目录复制到客户端目录，而是在终端上显示文件的内容。我是c的新手，这是我的任务。我知道UDP不是实现文件传输应用程序的最佳方法。但这就是我要做的。

这是服务器端：

#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 sendrecvflag 0 
#define nofile "File Not Found!" 

// funtion to clear buffer 
void clearBuf(char* b) 
{ 
    int i; 
    for (i = 0; i < NET_BUF_SIZE; i++) 
        b[i] = '\0'; 
} 

// funtion to encrypt 
char Cipher(char ch) 
{ 
    return ch ^ cipherKey; 
} 

// funtion sending file 
int sendFile(FILE* fp, char* buf, int s) 
{ 
    int i, len; 
    if (fp == NULL) { 
        strcpy(buf, nofile); 
        len = strlen(nofile); 
        buf[len] = EOF; 
        for (i = 0; i <= len; i++) 
            buf[i] = Cipher(buf[i]); 
        return 1; 
    } 

    char ch, ch2; 
    for (i = 0; i < s; i++) { 
        ch = fgetc(fp); 
        ch2 = Cipher(ch); 
        buf[i] = ch2; 
        if (ch == EOF) 
            return 1; 
    } 
    return 0; 
} 

// driver code 
int main() 
{ 
    int sockfd, 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_buf[NET_BUF_SIZE]; 
    FILE* fp; 

    // socket() 
    sockfd = socket(AF_INET, SOCK_DGRAM, IP_PROTOCOL); 

    if (sockfd < 0) 
        printf("\nfile descriptor not received!!\n"); 
    else
        printf("\nfile descriptor %d received\n", sockfd); 

    // bind() 
    if (bind(sockfd, (struct sockaddr*)&addr_con, sizeof(addr_con)) == 0) 
        printf("\nSuccessfully binded!\n"); 
    else
        printf("\nBinding Failed!\n"); 

    while (1) { 
        printf("\nWaiting for file name...\n"); 

        // receive file name 
        clearBuf(net_buf); 

        nBytes = recvfrom(sockfd, net_buf, 
                          NET_BUF_SIZE, sendrecvflag, 
                          (struct sockaddr*)&addr_con, &addrlen); 

        fp = fopen(net_buf, "r"); 
        printf("\nFile Name Received: %s\n", net_buf); 
        if (fp == NULL) 
            printf("\nFile open failed!\n"); 
        else
            printf("\nFile Successfully opened!\n"); 

        while (1) { 
            if (sendFile(fp, net_buf, NET_BUF_SIZE)) { 
                sendto(sockfd, net_buf, NET_BUF_SIZE, 
                       sendrecvflag,  
                    (struct sockaddr*)&addr_con, addrlen); 
                break; 
            } 

            // send 
            sendto(sockfd, net_buf, NET_BUF_SIZE, 
                   sendrecvflag, 
                (struct sockaddr*)&addr_con, addrlen); 
            clearBuf(net_buf); 
        } 
        if (fp != NULL) 
            fclose(fp); 
    } 
    return 0; 
}

这是客户端：

#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 sendrecvflag 0 

// funtion to clear buffer 
void clearBuf(char* b) 
{ 
    int i; 
    for (i = 0; i < NET_BUF_SIZE; i++) 
        b[i] = '\0'; 
} 

// function for decryption 
char Cipher(char ch) 
{ 
    return ch ^ cipherKey; 
} 

// function to receive file 
int recvFile(char* buf, int s) 
{ 
    int i; 
    char ch; 
    for (i = 0; i < s; i++) { 
        ch = buf[i]; 
        ch = Cipher(ch); 
        if (ch == EOF) 
            return 1; 
        else
            printf("%c", ch); 
    } 
    return 0; 
} 

// driver code 
int main() 
{ 
    int sockfd, 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_buf[NET_BUF_SIZE]; 
    FILE* fp; 

    // socket() 
    sockfd = socket(AF_INET, SOCK_DGRAM, IP_PROTOCOL); 

    if (sockfd < 0) 
        printf("\nfile descriptor not received!!\n"); 
    else
        printf("\nfile descriptor %d received\n", sockfd); 

    while (1) { 
        printf("\nPlease enter file name to receive:\n"); 
        scanf("%s", net_buf); 
        sendto(sockfd, net_buf, NET_BUF_SIZE, sendrecvflag, (struct sockaddr*)&addr_con, addrlen); 

        printf("\n---------Data Received---------\n"); 

        while (1) { 
            // receive 
            clearBuf(net_buf); 
            nBytes = recvfrom(sockfd, net_buf, NET_BUF_SIZE, sendrecvflag, (struct sockaddr*)&addr_con, &addrlen); 

            // process 
            if (recvFile(net_buf, NET_BUF_SIZE)) { 
                break; 
            } 
        } 
        printf("\n-------------------------------\n"); 
    } 
    return 0; 
} 

我需要将文件从服务器复制到客户端