网络编程第三次作业

tftp客户端：

#include <stdio.h>
#include <sys/types.h>          
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/stat.h>
#include <fcntl.h>

//下载功能函数
int download_data(int sfd,struct sockaddr_in sin)
{
    //获取文件名
    char filename[20]={0};
    printf("input filename:");
    scanf("%s",filename);

    //组装下载请求包
    char down_request[100]={0};
    short *p1_req=(short *)down_request;
    *p1_req=htons(1);                       //操作码

    char *p2_req=down_request+2;
    strcpy(p2_req,filename);                //文件名

    char *p3_req=p2_req+strlen(p2_req)+1;
    strcpy(p3_req,"octet");

    int req_len=9+strlen(filename);

    //向服务器发送下载请求
    int ret_sendto=sendto(sfd,down_request,req_len,0,(struct sockaddr *)&sin,sizeof(sin));
    if (ret_sendto<0)
    {
        perror("download reqest send failed");
        return -1;
    }
    printf("download request send success\n");

    //接收数据包并解包
    struct sockaddr_in ser_addr;
    char get_data[600]={0};
    char ack[4]={0};
    socklen_t addrlen=sizeof(ser_addr);
    int data_fd=open(filename,O_CREAT|O_APPEND|O_RDWR);
    if (data_fd<0)
    {
        printf("open failed");
        return -1;
    }
    while (1)
    {
        int ret_recvfrom=recvfrom(sfd,get_data,sizeof(get_data),0,(struct sockaddr *)&ser_addr,&addrlen);
        if (ret_recvfrom<0)
        {
            perror("recvform failed");
            return -1;
        }

        //组装ACK包
        // 组装ACK包
        short *p_ack1=(short *)ack;
        *p_ack1=htons(4); // ACK 操作码为 4

        short *p_ack2=(short *)(ack + 2);
        short block_number = ntohs(*((short *)(get_data + 2))); // 解析数据包中的 block number
        *p_ack2 = htons(block_number); // 设置 ACK 包中的 block number

        //写入文件
        int ret_write=write(data_fd,get_data+4,ret_recvfrom - 4);

        //发送ACK包
        int ret_ack=sendto(sfd,ack,4,0,(struct sockaddr *)&ser_addr,addrlen);
        if (ret_ack<0)
        {
            perror("ACK send failed");
            return -1;
        }

        if (ret_recvfrom<516)
            break;
    }

}

// 上传功能函数
int upload_data(int sfd, struct sockaddr_in sin)
{
    // 获取文件名
    char filename[20] = {0};
    printf("input filename to upload: ");
    scanf("%s", filename);

    // 打开文件
    int file_fd = open(filename, O_RDONLY);
    if (file_fd < 0)
    {
        perror("open file failed");
        return -1;
    }

    // 组装上传请求包
    char up_request[100] = {0};
    short *p1_req = (short *)up_request;
    *p1_req = htons(2); // 操作码2表示上传请求

    char *p2_req = up_request + 2;
    strcpy(p2_req, filename); // 文件名

    char *p3_req = p2_req + strlen(p2_req) + 1;
    strcpy(p3_req, "octet");

    int req_len = 9 + strlen(filename);

    // 向服务器发送上传请求
    int ret_sendto = sendto(sfd, up_request, req_len, 0, (struct sockaddr *)&sin, sizeof(sin));
    if (ret_sendto < 0)
    {
        perror("upload request send failed");
        close(file_fd);
        return -1;
    }
    printf("upload request send success\n");

    // 接收ACK包
    struct sockaddr_in ser_addr;
    char ack[4] = {0};
    socklen_t addrlen = sizeof(ser_addr);
    int ret_recvfrom = recvfrom(sfd, ack, sizeof(ack), 0, (struct sockaddr *)&ser_addr, &addrlen);
    if (ret_recvfrom < 0)
    {
        perror("recvfrom failed");
        close(file_fd);
        return -1;
    }

    // 检查ACK包
    short *p_ack = (short *)ack;
    if (ntohs(p_ack[0]) != 4 || ntohs(p_ack[1]) != 0)
    {
        printf("unexpected ACK received\n");
        close(file_fd);
        return -1;
    }
    printf("ACK received, start uploading\n");

    // 上传文件数据
    char data_packet[516] = {0};
    short block_number = 1;
    int read_len;

    while (1)
    {
        // 组装数据包
        memset(data_packet, 0, sizeof(data_packet));
        short *p_data_opcode = (short *)data_packet;
        *p_data_opcode = htons(3); // 操作码3表示数据包

        short *p_block_num = (short *)(data_packet + 2);
        *p_block_num = htons(block_number);

        // 读取文件数据
        read_len = read(file_fd, data_packet + 4, 512);
        if (read_len < 0)
        {
            perror("file read failed");
            close(file_fd);
            return -1;
        }

        // 发送数据包
        int ret_sendto = sendto(sfd, data_packet, read_len + 4, 0, (struct sockaddr *)&ser_addr, addrlen);
        if (ret_sendto < 0)
        {
            perror("data send failed");
            close(file_fd);
            return -1;
        }

        // 接收ACK包
        ret_recvfrom = recvfrom(sfd, ack, sizeof(ack), 0, (struct sockaddr *)&ser_addr, &addrlen);
        if (ret_recvfrom < 0)
        {
            perror("recvfrom failed");
            close(file_fd);
            return -1;
        }

        // 检查ACK包
        p_ack = (short *)ack;
        if (ntohs(p_ack[0]) != 4 || ntohs(p_ack[1]) != block_number)
        {
            printf("unexpected ACK received\n");
            close(file_fd);
            return -1;
        }

        printf("block %d uploaded, ACK received\n", block_number);

        // 判断文件是否发送完毕
        if (read_len < 512)
            break;

        // 更新块号
        block_number++;
    }

    printf("file upload completed\n");
    close(file_fd);
    return 0;
}

int main(int argc, char const *argv[])
{
    //创建报式套接字
    int sfd=socket(AF_INET,SOCK_DGRAM,0);
    if (sfd<0)
    {
        perror("socket failed (client)");
        return -1;
    }
    printf("socket_t success (client)\n");

    //允许端口号快速重用
    int reuse = 1;
    if(setsockopt(sfd, SOL_SOCKET, SO_REUSEADDR, &reuse, sizeof(reuse)) < 0)
    {
        perror("setsockopt failed (client)");
        return -1;
    }                                                                              
    printf("reuseaddr success (client)\n");

    printf("input service IP for argv[1]!");

    //创建服务器地址信息结构体
    struct sockaddr_in sin;
    sin.sin_family=AF_INET;
    sin.sin_port=htons(69);
    sin.sin_addr.s_addr=inet_addr(argv[1]);

    //功能循环
    int loop=1;
    int choice;
    while (loop)
    {
        //界面
        printf("**************************************\n");
        printf("***** 1-download 2-upload 3-exit *****\n");
        printf("**************************************\n");
        printf("input your choice:");
        scanf("%d",&choice);
        while (getchar()!='\n');
        
        switch (choice)
        {
        //下载功能
        case 1:
            download_data(sfd,sin);
            break;
        //上传功能
        case 2:
            upload_data(sfd, sin);
            break;
        //退出
        case 3:
            loop=0;
            break;
        default:
            printf("input right num!\n");
        }
        

    }

    return 0;
}