【嵌入式学习】网络通信基础-Day2-TCP和UDP基础通信模型

思维导图&笔记

见原文：EmbeddedNote：TCP和UDP基础通信模型 - Jun (lingjun.life)

UDP机械臂测试

机械臂
通过w(红色臂角度增大)s（红色臂角度减小）d（蓝色臂角度增大）a（蓝色臂角度减小）按键控制机械臂
注意：关闭计算机的杀毒软件，电脑管家，防火墙
1）基于UDP服务器的机械臂，端口号是8888， ip是Windows的ip；
查看Windows的IP：按住Windows+r 按键，输入cmd , 输入ipconfig
2）点击软件中的开启监听；
3）机械臂需要发送16进制数，共5个字节，协议如下

    0xff    0x02    x   y   0xff
0xff：起始结束协议，固定的；
0x02：控制机械手臂协议，固定的；
x：指定要操作的机械臂
    0x00 红色摆臂
    0x01 蓝色摆臂
y：指定角度

/*
 * Filename: 02tcpClint.c
 * Author: linus
 * Date: 2024-01-12
 * Version: 1.0
 *
 * Description: The purpose of this code.
 */

#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <pthread.h>
#include <string.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/msg.h>

#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

int cfd;
struct sockaddr_in cin;
char send_buf[5];

int RobArmCtl(char buf[128])
{
    static int x = 0, y = 0;

    switch (buf[0])
    {
    case 'W':
        x++;
        send_buf[2] = 0x00;
        send_buf[3] = x;
        break;
    case 'S':
        send_buf[2] = 0x00;
        send_buf[3] = x;
        x--;
        break;
    case 'A':
        y++;
        send_buf[2] = 0x01;
        send_buf[3] = y;
        break;
    case 'D':
        y--;
        send_buf[2] = 0x01;
        send_buf[3] = y;
        break;
    default:
        break;
    }

    send_buf[0] = 0xff;
    send_buf[1] = 0x02;

    send_buf[4] = 0xff;
    write(cfd, send_buf, sizeof(send_buf));
}

int init()
{
    send_buf[0] = 0xff;
    send_buf[1] = 0x02;
    send_buf[2] = 0x00;
    send_buf[3] = 0x00;
    send_buf[4] = 0xff;
    write(cfd, send_buf, sizeof(send_buf));

    send_buf[0] = 0xff;
    send_buf[1] = 0x02;
    send_buf[2] = 0x01;
    send_buf[3] = 90;
    send_buf[4] = 0xff;
    write(cfd, send_buf, sizeof(send_buf));
}

int main(int argc, const char *argv[])
{
    // 创建套接字
    cfd = socket(AF_INET, SOCK_STREAM, 0);

    cin.sin_family = AF_INET;
    cin.sin_port = htons(8888);
    cin.sin_addr.s_addr = inet_addr("192.168.125.27");

    // 连接服务器
    connect(cfd, (struct sockaddr *)&cin, sizeof(cin));
    init();

    char buf[128] = "";
    while (1)
    {
        printf("请输入指令：");
        fgets(buf, sizeof(buf), stdin);
        buf[strlen(buf) - 1] = '\0';
        RobArmCtl(buf);
        printf("指令发送成功\n");
    }

    return 0;
}