在udp服务器中接收最新的数据包 – C.

我的简单UDP服务器的代码：

int main(void) {
    int fd;
    int port = 5678;
    char buffer[1024];
    fd_set readfs;
    socklen_t client_length;
    struct timeval timeout_interval;
    struct sockaddr_in6 server_addr;
    struct sockaddr_in6 client_addr;
    int result;
    int recv;
    char client_addr_ipv6[100];

    fd = socket(PF_INET6,SOCK_DGRAM,0);
    printf(" e[1m e[34m ---------------------------------------- n--------------------  UDP SERVER --------------------n   e[39m e[0m n");
    printf("Process: e[34m %d e[49m Port ..n",port);

    if (fd < 0) {
        printf("ERR: fd < 0");
    } else {
        memset(&server_addr,sizeof(server_addr));
        server_addr.sin6_family = AF_INET6;
        server_addr.sin6_addr = in6addr_any;
        server_addr.sin6_port = htons(port);
        memset(&client_addr,sizeof(client_addr));
        client_addr.sin6_family = AF_INET6;
        client_addr.sin6_addr = in6addr_any;
        client_addr.sin6_port = htons(port);

        if (bind(fd,(struct sockaddr *) &server_addr,sizeof(server_addr))
                >= 0) {
            printf("e[1m INFO: e[0m e[34m Bind success.. e[39mn");

        } else {
            printf("Bind.");
            return -1;
        }
        for (;;) {
            FD_ZERO(&readfs);
            FD_SET(fd,&readfs);
            int max_fd = MAX(0,fd);
            timeout_interval.tv_sec = 3;
            timeout_interval.tv_usec = 50000000;

            result = select(max_fd + 1,&readfs,NULL,&timeout_interval);
            //printf("n %d t %d n",result,fd);
            if (result < 0) {
                printf("ERRn");
            } else if (result == 0) {
                printf("nTimeoutn");
            } else {
                if (FD_ISSET(fd,&readfs)) {
                    client_length = sizeof(client_addr);
                    if ((recv = recvfrom(fd,buffer,sizeof(buffer),(struct sockaddr *) &client_addr,&client_length))
                            < 0) {
                        printf("Recv-ERR!");
                        break;
                    }
                    inet_ntop(AF_INET6,&(client_addr.sin6_addr),client_addr_ipv6,100);
                    //printf("Client IP/Port : %s  ",client_addr_ipv6);

                    printf("n ------------------------------------------ n");
                    printf("e[1m Data: e[0m  e[32m %.*s n Client IP/Port : e[34m %s / %d ne[39m",recv,ntohs(client_addr.sin6_port));
                }
            }
        }
    }
}