将UDP集成到MENUOS环境中_thingsboard udp集成-优快云博客

本文链接：https://blog.youkuaiyun.com/Yi_chengzhao/article/details/85116832

本文详细介绍了如何在C语言中实现UDP服务器与客户端的通信过程。通过修改main.c文件，添加Server, StartServer 和 Client三个函数，实现了数据包的发送与接收。在服务器端，代码创建了一个UDP套接字并绑定到特定端口，接收来自客户端的消息并回复。客户端则创建UDP套接字，向服务器发送消息并接收回应。

1.修改main.c文件：

添加Server,StartServer,Client三个函数,将下列代码直接添加到main.c中：

#include<sys/types.h>
#include<sys/socket.h>
#include<netinet/in.h>
#include<arpa/inet.h>
#include<unistd.h>
#include<stdlib.h>
#include<stdio.h>
#include<string.h>
#include<netdb.h>
#include<errno.h>

#define PORT 8888
#define MAX_MSG_SIZE 1024

int Server(void)
{
   int sockfd, addrlen, n;
   struct sockaddr_in addr;
   char msg[10];
   char str[]={"hi"};
   sockfd = socket(AF_INET, SOCK_DGRAM, 0);
   if (sockfd < 0)
   {
      fprintf(stderr, "socket failed\n");
      exit(EXIT_FAILURE);
   }
   addrlen = sizeof(struct sockaddr_in);
   bzero(&addr, addrlen);
   addr.sin_family = AF_INET;
   addr.sin_addr.s_addr = htonl(INADDR_ANY);
   addr.sin_port = htons(PORT);
   if (bind(sockfd, (struct sockaddr*)(&addr), addrlen) < 0)
   {
      fprintf(stderr, "bind fail\n");
      exit(EXIT_FAILURE);
   }


      n = recvfrom(sockfd, msg, sizeof(msg), 0, (struct sockaddr *)(&addr), &addrlen);
      fprintf(stdout, "Recevie message from client is %s\n", msg);
      printf("Server endpoint input message %s\n", str);
      sendto(sockfd, str, n, 0,(struct sockaddr *)(&addr), addrlen);

   close(sockfd);
   return 0;
}

int StartServer(int argc, char *argv[])
{
   int pid;
   /* fork another process */
   pid = fork();
   if (pid < 0)
   {
       /* error occurred */
       fprintf(stderr, "Fork Failed!");
       exit(-1);
   }
   else if (pid == 0)
   {
       /*   child process    */
       Server();
       printf("Reply hi TCP Service Started!\n");
   }
   else
   {
       /*    parent process   */
       printf("Please input udpC...\n");
   }
}

int Client()
{
   int sockfd, addrlen, n;
   char buffer[]={"hello"};
   struct sockaddr_in addr;
   sockfd = socket(AF_INET, SOCK_DGRAM, 0);
   if (sockfd < 0)
   {
      fprintf(stderr, "socket falied\n");
      exit(EXIT_FAILURE);
   }
   addrlen = sizeof(struct sockaddr_in);
   bzero(&addr, addrlen);
   addr.sin_family = AF_INET;
   addr.sin_port = htons(PORT);
   addr.sin_addr.s_addr = htonl(INADDR_ANY);


       sendto(sockfd, buffer, strlen(buffer), 0, (struct sockaddr *)(&addr), addrlen);
       printf("client send msg is %s\n", buffer);
       n = recvfrom(sockfd, buffer, 10, 0, (struct sockaddr *)(&addr), &addrlen);
       fprintf(stdout, "clinet Receive message from server is %s\n", buffer);

   close(sockfd);
   return 0;
}