memset(&addr_server,0,sizeof(addr_server));
addr_server.sin_family=PF_INET;
addr_server.sin_addr.s_addr=htonl(INADDR_ANY);//第一步需要設置D類多播地址
addr_server.sin_port=htons(8000);
len=sizeof(addr_server);
sock_fd=socket(PF_INET,SOCK_DGRAM,0);
bind(sock_fd,(struct sockaddr*)&addr_server,len);
struct ip_mreq member; //把自己加入組播
member.imr_multiaddr.s_addr=inet_addr("224.0.0.15");//需要加入的組播地址
member.imr_interface.s_addr=htonl(INADDR_ANY);//把自己加入
//使自己的套接字可以收到組播信息
setsockopt(sock_fd,IPPROTO_IP,IP_ADD_MEMBERSHIP,&member,sizeof(member));
//服務器端
memset(&addr_server,0,sizeof(addr_server)); addr_server.sin_family=PF_INET; addr_server.sin_addr.s_addr=inet_addr("224.0.0.15");//第一步需要設置D類多播地址 addr_server.sin_port=htons(8000); len=sizeof(addr_server);
sock_fd=socket(PF_INET,SOCK_DGRAM,0); int loop=1;//是否允許組播用輪詢 setsockopt(sock_fd,IPPROTO_IP,IP_MULTICAST_LOOP,&loop,sizeof(loop));
廣播的實現
memset(&addr_server,0,sizeof(addr_server)); addr_server.sin_family=PF_INET; addr_server.sin_addr.s_addr=inet_addr("192.168.1.255");//第一步需要設置廣播地址 addr_server.sin_port=htons(8000); len=sizeof(addr_server); sock_fd=socket(PF_INET,SOCK_DGRAM,0); int can_broad=1;//設置允許廣播,默認關閉廣播的 setsockopt(sock_fd,SOL_SOCKET,SO_BROADCAST,&can_broad,sizeof(can_broad));