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

#define BUF_SIZE 100
int main(){
    //创建套接字
    int serv_sock = socket(AF_INET, SOCK_DGRAM, 0);
    //将套接字和IP、端口绑定
    struct sockaddr_in serv_addr;
    memset(&serv_addr, 0, sizeof(serv_addr));  //每个字节都用0填充
    serv_addr.sin_family = AF_INET;  //使用IPv4地址
    serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);  //具体的IP地址
    serv_addr.sin_port = htons(1234);  //端口
    bind(serv_sock, (struct sockaddr*)&serv_addr, sizeof(serv_addr));
    //接收客户端请求
    struct sockaddr_in clnt_addr;
    socklen_t clnt_addr_size = sizeof(clnt_addr);
    char buffer[BUF_SIZE] = {0};  //缓冲区
    while(1){
          memset(&buffer, 0, sizeof(buffer));  //每个字节都用0填充
        int strLen = recvfrom(serv_sock, buffer, BUF_SIZE, 0, (struct sockaddr *)&clnt_addr, &clnt_addr_size);
        if(strLen==-1){
            printf("recieve fail\n");
           // return 0;
        }else{
        printf("recieve:%s\n",buffer);
        sendto(serv_sock, buffer, strLen, 0, (struct sockaddr *)&clnt_addr, clnt_addr_size);
        }
    }
    close(serv_sock);
    return 0;
}