LWIP中基于UDP SOCKET组播功能的实现

/*******************************************************File name: MulticastUtility.cDescription: 组播功能的实现Author: 陈龙JasonVersion: v1.0********************************************************/#include "MulticastUtility.h"#include "igmp.h"struct udp_pcb *multicast_client_udp = NULL;/** * Function: multicastServerRecv * Description: 组播服务器接收到数据后的回调函数 * @param arg 回调时传递回来的参数 * @param pcb 当前连接的PCB * @param p   存放接收到数据的BUF * @param addr 发送数据的IP地址 * @param port 发送数据的端口号**/void multicastServerRecv(void *arg, struct udp_pcb *pcb, struct pbuf *p, ip_addr_t *addr, u16_t port){    printf("recv remote multicast data\n\r");}/** * Function: createMulticastListen * Description: 创建组播监听端**/void createMulticastListen(){    struct udp_pcb *multicast_udp;    ip_addr_t multicast_addr;    err_t err_status;    //IP4_ADDR(&multicast_addr,224,1,1,210);    IP4_ADDR(&multicast_addr, 233, 233, 233, 233);    multicast_udp = udp_new();    if( !multicast_udp){        printf("create multicast udp failed\n\r");        return;    }    err_status = udp_bind(multicast_udp,&multicast_addr,6666);    if(err_status != ERR_OK){        printf("bind multicast udp failed\n\r");        return;    }    igmp_joingroup(IP_ADDR_ANY,&multicast_addr);    igmp_joingroup(&veth_netif.ip_addr,&multicast_addr);    udp_recv(multicast_udp,multicastServerRecv,NULL);}/** * Function: createMulticastListen * Description: 创建组播的客户端模式**/void createMulticastClient(){    int retValue = 0;    err_t err_status;    uint8_t i;    struct pbuf *udp_data_packet;    ip_addr_t ipaddr;//定义IP类型变量    udp_data_packet = pbuf_alloc(PBUF_RAW,20,PBUF_RAM);    if(!udp_data_packet){        printf("serial udp memory allocate\n\r");    }    IP4_ADDR(&ipaddr,233,233,233,233);    if(multicast_client_udp == NULL){        multicast_client_udp = udp_new();        if( !multicast_client_udp){            printf("create udp pcb failed\n\r");            return;        }        /* 先绑定udp链接 */        err_status = udp_bind(multicast_client_udp,IP_ADDR_ANY,9675);    //绑定任意地址和1233端口        if(err_status != ERR_OK){  //绑定失败            printf("serial client udp bind failed\n\r");            return ;        }        err_status = udp_connect(multicast_client_udp,&ipaddr,4002);   //与远程NTP服务器建立连接        if(err_status != ERR_OK){  //创建连接失败            printf("serial client udp create connect failed\n\r");            return;        }        udp_recv(multicast_client_udp,multicastClientRecv,NULL);    }    memset(udp_data_packet->payload,0,udp_data_packet->len);    memcpy(udp_data_packet->payload,"hello server",13);    err_status = udp_send(multicast_client_udp,udp_data_packet);    }/** * Function: multicastClientRecv * Description: 组播客户端接收到数据后的回调函数 * @param arg 回调时传递回来的参数 * @param pcb 当前连接的PCB * @param p   存放接收到数据的BUF * @param addr 发送数据的IP地址 * @param port 发送数据的端口号**/void multicastClientRecv(void *arg, struct udp_pcb *pcb, struct pbuf *p, ip_addr_t *addr, u16_t port){    printf("udp client recv data \n\r");//在函数体中添加具体功能}

udp_bind():