Socket编程实现简单的UDP通信、广播、组播

1 UDP通信

1.1 实现流程

1.2 程序示例

1.2.1 服务端

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

using namespace std;

int main() {
   
   
    int fd;
    sockaddr_in addr;
    sockaddr_in clientaddr;
    socklen_t len;
    char recvBuf[1024];

    if((fd = socket(PF_INET, SOCK_DGRAM, 0)) == -1) {
   
   
        perror("socket");
        exit(-1);
    }

    addr.sin_family = PF_INET;
    addr.sin_addr.s_addr = htonl(INADDR_ANY);
    addr.sin_port = htons(9999);

    if(bind(fd, (sockaddr *)&addr, sizeof(addr)) == -1) {
   
   
        perror("bind");
        exit(-1);
    }

    //通信
    while(1) {
   
   
        //接收数据
        len = sizeof(clientaddr);
        int num = recvfrom(fd, recvBuf, sizeof(recvBuf), 0, (sockaddr *)&clientaddr, &len);

        char Clientip[16];
        inet_ntop(AF_INET, &clientaddr.sin_addr.s_addr, Clientip, 16);
        cout << "client ip" << Clientip << ", port:" << ntohs(clientaddr.sin_port) << endl;

        cout << "(SERVER)" << "recv client data: " << recvBuf << endl;

        sendto(fd, recvBuf, strlen(recvBuf) + 1, 0, (sockaddr *)&clientaddr, len);
    }

    close(fd);
    return 0;
}

1.2.2 客户端

#include