Cellular Network Infrastructure » Radio Access Network » OsmoBTS

	/* Themyscira addition: empty RTP "ticks" on FACCH */

	if (data_ind->sapi == GsmL1_Sapi_FacchF)

		l1if_tch_rx_facch(trx, chan_nr, l1p_msg);

int l1if_tch_rx_facch(struct gsm_bts_trx *trx, uint8_t chan_nr,

		      struct msgb *l1p_msg);

/*

 * The following function is a Themyscira Wireless addition: we want to have

 * an RTP packet sent out on *every* 20 ms "tick", even during times when

 * TCH was stolen for FACCH.  During FACCH stealing times, it appears that

 * sysmoBTS PHY sends GsmL1_Sapi_FacchF and no GsmL1_Sapi_TchF, and with

 * the original code l1if_tch_rx(), the function that feeds "ticks" to the

 * RTP output mechanism, was never called.  Our added l1if_tch_rx_facch()

 * function sends an empty payload to the upper layers, and we call it

 * from the GsmL1_Sapi_FacchF code path.

 */

int l1if_tch_rx_facch(struct gsm_bts_trx *trx, uint8_t chan_nr,

		      struct msgb *l1p_msg)

{

	GsmL1_Prim_t *l1p = msgb_l1prim(l1p_msg);

	GsmL1_PhDataInd_t *data_ind = &l1p->u.phDataInd;

	struct msgb *rmsg = NULL;

	struct gsm_lchan *lchan = &trx->ts[L1SAP_CHAN2TS(chan_nr)].lchan[l1sap_chan2ss(chan_nr)];

	if (is_recv_only(lchan->abis_ip.speech_mode))

		return -EAGAIN;

	LOGPFN(DL1P, LOGL_DEBUG, data_ind->u32Fn, "chan_nr %d Rx FACCH\n", chan_nr);

	/* Push empty payload to upper layers */

	rmsg = msgb_alloc_headroom(256, 128, "L1P-to-RTP");

	return add_l1sap_header(trx, rmsg, lchan, chan_nr, data_ind->u32Fn,

				data_ind->measParam.fBer * 10000,

				data_ind->measParam.fLinkQuality * 10,

				0,	/* suppress RSSI like in osmo-bts-trx */

				data_ind->measParam.i16BurstTiming * 64,

				0);

}