udp广播的例子

在这里插入图片描述

以下是一个使用C语言描述广播发送和接收的简单示例：

发送端（广播发送）：

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

#define BROADCAST_PORT 8888
#define BROADCAST_ADDRESS "192.168.1.255"  // 替换为您的广播地址

int main() {
    int sockfd;
    struct sockaddr_in broadcastAddr;
    char *broadcastMsg = "Hello, broadcast!";

    // 创建UDP套接字
    if ((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
        perror("socket creation failed");
        exit(EXIT_FAILURE);
    }

    // 设置广播选项
    int broadcastEnable = 1;
    if (setsockopt(sockfd, SOL_SOCKET, SO_BROADCAST, &broadcastEnable, sizeof(broadcastEnable)) < 0) {
        perror("setsockopt failed");
        exit(EXIT_FAILURE);
    }

    // 设置广播地址和端口
    memset(&broadcastAddr, 0, sizeof(broadcastAddr));
    broadcastAddr.sin_family = AF_INET;
    broadcastAddr.sin_port = htons(BROADCAST_PORT);
    if (inet_pton(AF_INET, BROADCAST_ADDRESS, &broadcastAddr.sin_addr) <= 0) {
        perror("inet_pton failed");
        exit(EXIT_FAILURE);
    }

    // 发送广播消息
    if (sendto(sockfd, broadcastMsg, strlen(broadcastMsg), 0, (struct sockaddr*)&broadcastAddr, sizeof(broadcastAddr)) < 0) {
        perror("sendto failed");
        exit(EXIT_FAILURE);
    }

    printf("Broadcast message sent.\n");

    close(sockfd);

    return 0;
}

接收端（广播接收）：

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

#define BROADCAST_PORT 8888

int main() {
    int sockfd;
    struct sockaddr_in myAddr, senderAddr;
    char recvBuffer[1024];
    socklen_t senderLen = sizeof(senderAddr);

    // 创建UDP套接字
    if ((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
        perror("socket creation failed");
        exit(EXIT_FAILURE);
    }

    // 设置接收端地址和端口
    memset(&myAddr, 0, sizeof(myAddr));
    myAddr.sin_family = AF_INET;
    myAddr.sin_addr.s_addr = htonl(INADDR_ANY);
    myAddr.sin_port = htons(BROADCAST_PORT);

    // 绑定套接字到接收端地址
    if (bind(sockfd, (struct sockaddr*)&myAddr, sizeof(myAddr)) < 0) {
        perror("bind failed");
        exit(EXIT_FAILURE);
    }

    // 接收广播消息
    if (recvfrom(sockfd, recvBuffer, sizeof(recvBuffer)-1, 0, (struct sockaddr*)&senderAddr, &senderLen) < 0) {
        perror("recvfrom failed");
        exit(EXIT_FAILURE);
    }

    // 打印接收到的广播消息
    printf("Received broadcast message: %s\n", recvBuffer);

    close(sockfd);

    return 0;
}