sa.sin_family = AF_INET;
sa.sin_port = htons(MCAST_PORT);
inet_pton(AF_INET, MCAST_ADDR, &sa.sin_addr);
memset(&mreq, 0, sizeof(mreq));
sa.sin_family = AF_INET;
sa.sin_port = htons(MCAST_PORT);
inet_pton(AF_INET, MCAST_ADDR, &sa.sin_addr);
memset(&mreq, 0, sizeof(mreq));