LWIP中的setsockopt调用返回错误

2016-05-19 07:37:16 1.2k 阅读 AI 写同款 · GEO 优化AI 选题数据监测一键分发 ›

LWIP实战指南：高效实现UDP广播与组播通信本文是一份针对嵌入式开发的LWIP实战指南，详细讲解了如何高效实现UDP广播与组播通信。文章从基础概念入手，通过清晰的代码示例，逐步指导开发者完成LWIP协议栈的关键配置、广播与组播的Socket编程，并利用Wireshark进行抓包分析，帮助读者掌握在物联网设备中实现精准、高效的一对多数据传输的核心技能与避坑要点。阅读详情

#define MCAST_PORT 8888

#define MCAST_ADDR "224.0.0.100"  

#define MCAST_INTERVAL 5                       



 #define BUFF_SIZE 256 

 void MultiClientThread(const char* url, int port){

    int socketfd;                                      /*套接字文件描述符*/

    struct sockaddr_in local_addr;              /*本地地址*/

    int err = -1;

    socketfd = socket(AF_INET, SOCK_DGRAM, 0);     /*建立套接字*/

        if (socketfd == -1)

        {

            DBGPRINT_LWIP("MulticastClient socket()\r\n");

            return ;

        }  

     memset(&local_addr, 0, sizeof(local_addr));

    local_addr.sin_family = AF_INET;

    local_addr.sin_addr.s_addr = htonl(INADDR_ANY);

    local_addr.sin_port = htons(MCAST_CLIENT_PORT);

   

                                                /*绑定socket*/

    err = bind(socketfd,(struct sockaddr*)&local_addr, sizeof(local_addr)) ;

        if(err < 0)

        {

            DBGPRINT_LWIP("bind()");

            return ;

        }

             int loop = 1;

     err = getsockopt(socketfd, SOL_SOCKET, SO_SNDBUF, &loop, sizeof(loop));

                 if(err < 0)

            {

                DBGPRINT_LWIP("getsockopt():SO_REUSEADDR error\r\n");

                return ;

            }

     err = setsockopt(socketfd,SOL_SOCKET, SO_REUSEADDR,&loop, sizeof(loop));

            if(err < 0)

            {

                DBGPRINT_LWIP("setsockopt():SO_REUSEADDR error\r\n");

                return ;

            }

 

    struct ip_mreq mreq;                                                       /*加入多播组*/

    mreq.imr_multiaddr.s_addr = inet_addr(MCAST_ADDR); /*多播地址*/

    mreq.imr_interface.s_addr = htonl(INADDR_ANY);           /*网络接口为默认*/

                                                                                              /*将本机加入多播组*/

    err = setsockopt(socketfd, IPPROTO_IP, IP_ADD_MEMBERSHIP,&mreq, sizeof(mreq));

            if (err < 0)

            {

                DBGPRINT_LWIP("setsockopt():IP_ADD_MEMBERSHIP error\r\n");

                return ;

            }

            else{

                 DBGPRINT_LWIP("setsockopt():IP_ADD_MEMBERSHIP OK!\r\n");

            }

    int times = 0;

    int addr_len = 0;

    char buff[BUFF_SIZE];

    int n = 0;

                                        /*循环接收多播组的消息，5次后退出*/

    while(1)

    {

        addr_len = sizeof(local_addr);

        memset(buff, 0, BUFF_SIZE);                 /*清空接收缓冲区*/

                                                    /*接收数据*/

        n = lwip_recvfrom(socketfd, buff, BUFF_SIZE, 0,(struct sockaddr*)&local_addr,&addr_len);

                if( n== -1)

                {

                    DBGPRINT_LWIP("recvfrom()\r\n");

                }

                                                    /*打印信息*/

        DBGPRINT_LWIP("Recv %dst message from server:%s\n", times, buff);

        sleep(MCAST_INTERVAL);

    }

     err = lwip_setsockopt(socketfd, IPPROTO_IP, IP_DROP_MEMBERSHIP,&mreq, sizeof(mreq));

    close(socketfd);

   

}