实验六、多播发送与接收程序设计.docVIP

实验六、多播发送与接收程序设计 一、参考程序 发送程序： //各调用函数定义 //本地接口local_if加入多播组mcaddr int mc_join(SOCKET s,struct in_addr *mcaddr, struct in_addr *local_if) { struct ip_mreq mreq; //首先用memcpy函数构造ip_mreq型的结构变量mreg memcpy((mreq.imr_interface), local_if, sizeof(struct in_addr)); // local if memcpy((mreq.imr_multiaddr), mcaddr, sizeof(struct in_addr)); // mutilcast group address return (setsockopt(s, IPPROTO_IP, IP_ADD_MEMBERSHIP, (char *)mreq, sizeof(mreq))); } // 为多播报文设置外出接口 int mc_setIF(SOCKET s, const DWORD local_out_if) { return (setsockopt(s, IPPROTO_IP, IP_MULTICAST_IF, (char *)local_out_if, sizeof(local_out_if))); } // 设置外出多播报文的ttl值，默认为1 int mc_setTTL(SOCKET s, const DWORD ttl) { return (setsockopt(s, IPPROTO_IP, IP_MULTICAST_TTL, (char *)ttl, sizeof(ttl))); } // 设置外出多播报文是否返回，默认为true int mc_setLoop(SOCKET s,const BOOL flag) { return (setsockopt(s,IPPROTO_IP,IP_MULTICAST_LOOP,(char *)flag,sizeof(flag))); } int mc_leave(SOCKET s,struct in_addr *mcaddr,struct in_addr *local_if)//指定成员推出指定多播组，为了通用性。一般程序运行结束会自动离开） { struct ip_mreq mreq; //构造ip_mreq结构变量 memcpy((mreq.imr_interface),local_if,sizeof(struct in_addr)); memcpy((mreq.imr_multiaddr),mcaddr,sizeof(struct in_addr)); return(setsockopt(s,IPPROTO_IP,IP_DROP_MEMBERSHIP,(char *)mreq,sizeof(mreq))); //主程序 void main() { WSADATA wsaData; WSAStartup(MAKEWORD(2,2),wsaData); SOCKET sock = socket(AF_INET,SOCK_DGRAM,0); struct sockaddr_in to; memset(to,0,sizeof(to)); to.sin_family=AF_INET; to.sin_port=htons(9999); to.sin_addr.S_un.S_addr=inet_addr(INADDR_ANY); bind(sock,(struct sockaddr *)to,sizeof(to)); struct in_addr mcaddr; mcaddr.s_addr =inet_addr(226.1.2.3); mc_join(sock,mcaddr,(to.sin_addr)); char buf[65] ; while(1){ memset(buf,0,65); recvfrom(sock,buf,64,0,NULL,NULL); printf(recvd: %s\n,buf); } } 发送程序： #pragma comment(lib,ws2_32.lib) #includewinsock2.h #includestdio.h void main(int argc,char* argv[]) { WSADATA wsaData;