sr_source_add(ufds[0].fd, ufds[0].events, 10, receive_data, sdi);
packet.type = SR_DF_HEADER;
packet.length = sizeof(struct sr_datafeed_header);
sr_source_add(ufds[0].fd, ufds[0].events, 10, receive_data, sdi);
packet.type = SR_DF_HEADER;
packet.length = sizeof(struct sr_datafeed_header);