传输udp的示例

港控/mmm° 2022-05-18 00:58 191阅读 0赞

工作中实际用到的demo，移植方便，亲测可用

**发送struct**

#include <unistd.h> 
    #include <sys/types.h> 
    #include <sys/socket.h> 
    #include <netinet/in.h> 
    #include <arpa/inet.h> 
    #include <stdlib.h> 
    #include <stdio.h> 
    #include <errno.h> 
    #include <string.h> 
    
    #define MYPORT 8887 
    char* SERVERIP = "127.0.0.1"; 
    
    typedef struct ViewStruct
    {
        float sim_time;
        float heli ;
    }ViewStruct;
    
    
    #define ERR_EXIT(m) \ 
        do \  
    { \  
        perror(m); \  
        exit(EXIT_FAILURE); \  
        } while(0)  
    
    void echo_cli(int sock,ViewStruct m_view)  
    {  
        int ret;  
        //unsigned char sendbuf[160];
    
        char* sendbuf = (char*)malloc(sizeof(ViewStruct)+1);
        memcpy(sendbuf,&m_view,sizeof(m_view));
    
      if ((sock = socket(PF_INET, SOCK_DGRAM, 0)) < 0)  
    
        ERR_EXIT("socket"); 
    
        struct sockaddr_in servaddr;  
        memset(&servaddr, 0, sizeof(servaddr));  
        servaddr.sin_family = AF_INET;  
        servaddr.sin_port = htons(MYPORT);  
        servaddr.sin_addr.s_addr = inet_addr(SERVERIP); 
    
        //char sendbuf[1024] = {0}; 
        //char recvbuf[1024] = {0}; 
    
        printf("向服务器发送：%lf\n",sendbuf); 
        sendto(sock, sendbuf, strlen(sendbuf), 0, (struct sockaddr *)&servaddr, sizeof(servaddr));  //这里的隐患在于struct转成字符串之后，使用sizeof或strlen函数计算长度遇到/0结束符后会自动停止，所以如果struct中数据有0，可以用数据个数*数长度的方法
    
        sleep(1);
           // ret = recvfrom(sock, recvbuf, sizeof(recvbuf), 0, NULL, NULL); 
           // printf("从服务器接收：%s\n",recvbuf);
    
          // memset(sendbuf, 0, sizeof(sendbuf)); 
          // memset(recvbuf, 0, sizeof(recvbuf)); 
    
        close(sock);  
    
    }  
    
    
    int main(void)  
    {  
        int sock;
    
        ViewStruct m_vie;
        m_vie.sim_time= 0.0125;
        m_vie.heli =0.02;
    
    //char sendbuf[1024] = {"123"}; 
    
    while(1)
    {
        echo_cli(sock,m_vie);  
    }    
        return 0;  
    }

**收struct**

#include<stdio.h> 
    #include<stdlib.h> 
    #include<unistd.h> 
    #include<errno.h> 
    #include<sys/types.h> 
    #include<sys/socket.h> 
    #include<netinet/in.h> 
    #include<string.h> 
    
    #define MYPORT 8887 
    
    
    #define ERR_EXIT(m) \ 
        do { \  
        perror(m); \  
        exit(EXIT_FAILURE); \  
        } while (0)  
    
    void echo_ser(int sock)  
    {  
        char recvbuf[1024] = {
       0};  
        struct sockaddr_in peeraddr;  
        socklen_t peerlen;  
        int n;  
    
    typedef struct ViewStruct
    {
        float sim_time;
        float heli ;
    }ViewStruct;
    
        while (1)  
        {  
    
            peerlen = sizeof(peeraddr);  
            memset(recvbuf, 0, sizeof(recvbuf));  
    
            n = recvfrom(sock, recvbuf, sizeof(recvbuf), 0,  
                         (struct sockaddr *)&peeraddr, &peerlen); 
    
            ViewStruct data;
            memcpy(&data,recvbuf,sizeof(data)+1);
    
            if (n <= 0)  
            {  
    
                if (errno == EINTR)  
                    continue;  
    
                ERR_EXIT("recvfrom error");  
            }  
            else if(n > 0)  
            {  
                //printf("接收到的数据：%f\n",recvbuf); 
                 printf("接收到的数据data：%f\n", data.sim_time); 
                 printf("接收到的数据data：%f\n", data.heli); 
             }  
        }  
        close(sock);  
    }  
    
    int main(void)  
    {  
        int sock;  
        if ((sock = socket(PF_INET, SOCK_DGRAM, 0)) < 0)  
            ERR_EXIT("socket error");  
    
        struct sockaddr_in servaddr;  
        memset(&servaddr, 0, sizeof(servaddr));  
        servaddr.sin_family = AF_INET;  
        servaddr.sin_port = htons(MYPORT);  
        servaddr.sin_addr.s_addr = htonl(INADDR_ANY);  
    
        printf("监听%d端口\n",MYPORT);  
        if (bind(sock, (struct sockaddr *)&servaddr, sizeof(servaddr)) < 0)  
            ERR_EXIT("bind error");  
    
        echo_ser(sock);  
        return 0;  
    }