UDP通信 广播 组播

# UDP通信

 

 # server.c

#include <stdio.h>
#include <string.h>
#include <arpa/inet.h>
#include <stdlib.h>
#include <unistd.h>

int main()
{
    int lfd = socket(AF_INET, SOCK_DGRAM, 0);
    char *ip_buf = "192.168.248.128";
    int ip;
    inet_pton(AF_INET, ip_buf, &ip);

    struct sockaddr_in saddr;
    saddr.sin_addr.s_addr = ip;
    saddr.sin_family = AF_INET;
    saddr.sin_port = htons(9999);
    bind(lfd, (struct sockaddr *) &saddr, sizeof(saddr));

    while(1)
    {
    
        char recvBuf[1024];
        struct sockaddr_in client_addr;
        int client_addr_len = sizeof(client_addr);
        
        // 第五个参数为传输参数，用于获取发送数据客户端的信息
        int len = recvfrom(lfd, recvBuf, sizeof(recvBuf), 0, (struct sockaddr *) &client_addr , &client_addr_len);
        if(len == -1)
        {
            perror("recvfrom");
            exit(-1);
        }
        else if(len == 0)
        {
            printf("client close······");
            exit(-1);
        }
        else
        {
            printf("recv info : %s\n", recvBuf);
        }
        char client_ipBuf[1024];
        inet_ntop(AF_INET, &client_addr.sin_addr.s_addr, client_ipBuf, sizeof(client_ipBuf));
        printf("client ip : %s, port : %d\n", client_ipBuf, ntohs(client_addr.sin_port));

        // 给客户端再回个数据
        sendto(lfd, recvBuf, strlen(recvBuf) + 1, 0, (struct sockaddr *) &client_addr, sizeof(client_addr));




    }
    close(lfd);






    return 0;
}

 

# client.c

#include <stdio.h>
#include <string.h>
#include <arpa/inet.h>
#include <stdlib.h>
#include <unistd.h>

int main()
{
    int lfd = socket(AF_INET, SOCK_DGRAM, 0);
    char *ip_buf = "192.168.248.128";
    int ip;
    inet_pton(AF_INET, ip_buf, &ip);

    struct sockaddr_in saddr;
    saddr.sin_addr.s_addr = ip;
    saddr.sin_family = AF_INET;
    saddr.sin_port = htons(9999);
    int num = 0;
    while(1)
    {
    
        char sendBuf[1024];
        sprintf(sendBuf, "hello, i am client %d\n", num++);

        sendto(lfd, sendBuf, strlen(sendBuf) + 1, 0, (struct sockaddr *) &saddr, sizeof(saddr));
        
        char recvBuf[1024];

        // 服务端的地址已经指定，不需要再获取了，置NULL即可        
        int len = recvfrom(lfd, recvBuf, sizeof(recvBuf), 0, NULL, NULL);
        if(len == -1)
        {
            perror("recvfrom");
            exit(-1);
        }
        else if(len == 0)
        {
            printf("server close······");
            exit(-1);
        }
        else
        {
            printf("recv info : %s\n", recvBuf);
        }
        sleep(1);


    }

    close(lfd);





    return 0;
}

 

 

# 广播

 

 

# server.c

#include <stdio.h>
#include <string.h>
#include <arpa/inet.h>
#include <stdlib.h>
#include <unistd.h>

int main()
{
    int lfd = socket(AF_INET, SOCK_DGRAM, 0);

    // 设置广播属性
    int opt = 1;
    setsockopt(lfd, SOL_SOCKET, SO_BROADCAST, &opt, sizeof(opt));

    // 创建一个广播地址
    char *ip_buf = "192.168.248.255";
    int ip;
    inet_pton(AF_INET, ip_buf, &ip);

    struct sockaddr_in saddr;
    saddr.sin_addr.s_addr = ip;
    saddr.sin_family = AF_INET;
    saddr.sin_port = htons(9999);
    int num = 0;
    while(1)
    {
    
        char sendBuf[1024];
        sprintf(sendBuf, "client...... %d\n", num++);

        sendto(lfd, sendBuf, strlen(sendBuf) + 1, 0, (struct sockaddr *) &saddr, sizeof(saddr));
        printf("广播数据：%s\n", sendBuf);
        
        sleep(1);


    }

    close(lfd);





    return 0;
}

 

# client.c

#include <stdio.h>
#include <string.h>
#include <arpa/inet.h>
#include <stdlib.h>
#include <unistd.h>

int main()
{
    int lfd = socket(AF_INET, SOCK_DGRAM, 0);
    char *ip_buf = "192.168.248.128";
    int ip;
    inet_pton(AF_INET, ip_buf, &ip);

    struct sockaddr_in saddr;
    saddr.sin_addr.s_addr = INADDR_ANY;
    saddr.sin_family = AF_INET;
    saddr.sin_port = htons(9999);
    bind(lfd, (struct sockaddr *) &saddr, sizeof(saddr)); // 谁先接收谁bind
    while(1)
    {
    
        char recvBuf[1024];
        struct sockaddr_in client_addr;
        int client_addr_len = sizeof(client_addr);
        
        // 第五个参数为传输参数，用于获取发送数据客户端的信息
        int len = recvfrom(lfd, recvBuf, sizeof(recvBuf), 0, NULL , NULL);
        if(len == -1)
        {
            perror("recvfrom");
            exit(-1);
        }
        else if(len == 0)
        {
            printf("client close······");
            exit(-1);
        }
        else
        {
            printf("recv info : %s\n", recvBuf);
        }
        // char client_ipBuf[1024];
        // inet_ntop(AF_INET, &client_addr.sin_addr.s_addr, client_ipBuf, sizeof(client_ipBuf));
        // printf("client ip : %s, port : %d\n", client_ipBuf, ntohs(client_addr.sin_port));




    }
    close(lfd);






    return 0;
}

 

# 组播

 

 

 # server.c

#include <stdio.h>
#include <string.h>
#include <arpa/inet.h>
#include <stdlib.h>
#include <unistd.h>

int main()
{
    int lfd = socket(AF_INET, SOCK_DGRAM, 0);

    // 设置多播地址
    struct in_addr opt;
    inet_pton(AF_IENT, "239.0.0.10", &opt.s_addr);

    setsockopt(lfd, IPPROTO_IP, IP_MULTICAST_IF, &opt, sizeof(opt));

    // 创建一个多播地址
    char *ip_buf = "239.0.0.10";
    int ip;
    inet_pton(AF_INET, ip_buf, &ip);

    struct sockaddr_in saddr;
    saddr.sin_addr.s_addr = ip;
    saddr.sin_family = AF_INET;
    saddr.sin_port = htons(9999);
    int num = 0;
    while(1)
    {
    
        char sendBuf[1024];
        sprintf(sendBuf, "client...... %d\n", num++);

        sendto(lfd, sendBuf, strlen(sendBuf) + 1, 0, (struct sockaddr *) &saddr, sizeof(saddr));
        printf("广播数据：%s\n", sendBuf);
        
        sleep(1);


    }

    close(lfd);





    return 0;
}

 

# client.c

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

int main()
{
    int lfd = socket(AF_INET, SOCK_DGRAM, 0);
    char *ip_buf = "192.168.248.128";
    int ip;
    inet_pton(AF_INET, ip_buf, &ip);

    struct sockaddr_in saddr;
    saddr.sin_addr.s_addr = INADDR_ANY;
    saddr.sin_family = AF_INET;
    saddr.sin_port = htons(9999);
    bind(lfd, (struct sockaddr *) &saddr, sizeof(saddr)); // 谁先接收谁bind

    // 加入多播组
    struct ip_mreq opt;
    inet_pton(AF_INET, "239.0.0.10", &opt.imr_multiaddr);
    opt.imr_interface = INADDR_ANY;
    setsockopt(lfd, IPPROTO_IP, IP_ADD_MEMBERSHIP, )
    
    while(1)
    {
    
        char recvBuf[1024];
        struct sockaddr_in client_addr;
        int client_addr_len = sizeof(client_addr);
        
        // 第五个参数为传输参数，用于获取发送数据客户端的信息
        int len = recvfrom(lfd, recvBuf, sizeof(recvBuf), 0, NULL , NULL);
        if(len == -1)
        {
            perror("recvfrom");
            exit(-1);
        }
        else if(len == 0)
        {
            printf("client close······");
            exit(-1);
        }
        else
        {
            printf("recv info : %s\n", recvBuf);
        }
        // char client_ipBuf[1024];
        // inet_ntop(AF_INET, &client_addr.sin_addr.s_addr, client_ipBuf, sizeof(client_ipBuf));
        // printf("client ip : %s, port : %d\n", client_ipBuf, ntohs(client_addr.sin_port));




    }
    close(lfd);






    return 0;
}