diff options
author | Mychaela N. Falconia <falcon@freecalypso.org> | 2023-03-28 20:29:58 +0000 |
---|---|---|
committer | laforge <laforge@osmocom.org> | 2023-03-30 17:30:53 +0000 |
commit | 61e7fdbb3fac93e0b15a9820b0d81dc4b5f20864 (patch) | |
tree | 99b8c8325311484c505ef73290789814672090e9 | |
parent | 50710f4e8ed463c821651b5fbe82f861e19e6295 (diff) |
sysmo: emit empty RTP ticks during FACCH stealing on TCH/F
When FACCH stealing occurs and sysmoBTS L1 delivers GsmL1_Sapi_FacchF
instead of GsmL1_Sapi_TchF, that 20 ms unit still needs to be
accounted for in the RTP timestamp cadence, and if we run with
rtp continuous-streaming enabled, then an actual BFI packet needs
to be emitted. The original code failed to do either; the present
change implements correct behavior for TCH/F.
The present patch only covers the case of TCH/F; handling of TCH/H
is left as a FIXME for other/later developers.
Related: OS#5974
Change-Id: I39d15faade28fb7d670493a99a0e0bdb654e2a4a
-rw-r--r-- | src/osmo-bts-sysmo/l1_if.c | 19 | ||||
-rw-r--r-- | src/osmo-bts-sysmo/l1_if.h | 2 | ||||
-rw-r--r-- | src/osmo-bts-sysmo/tch.c | 23 |
3 files changed, 44 insertions, 0 deletions
diff --git a/src/osmo-bts-sysmo/l1_if.c b/src/osmo-bts-sysmo/l1_if.c index 19f0c5aa..24a3d1e7 100644 --- a/src/osmo-bts-sysmo/l1_if.c +++ b/src/osmo-bts-sysmo/l1_if.c @@ -980,6 +980,25 @@ static int handle_ph_data_ind(struct femtol1_hdl *fl1, GsmL1_PhDataInd_t *data_i return rc; } + /* If we got FACCH, the RTP clock needs to account for it, + * and if we have rtp continuous-streaming enabled, + * an actual BFI packet will be emitted. + * + * Only the case of TCH/F is currently handled; the task of + * supporting TCH/H is left as a FIXME for other/later + * developers. The difficulty with supporting FACCH/H is that + * only one GsmL1_Sapi_FacchH message will be received, + * covering 40 ms of time, but two RTP "tick" output calls + * will need to be made, with appropriately adjusted frame + * numbers. As a further consideration for rtp continuous-streaming + * mode, having the two RTP BFI packets sent directly back to back, + * as opposed to proper 20 ms timing, may be so undesirable + * that some deployments may rather disable TCH/H (use only TCH/F) + * than deal with the extra pain, or use TCH/H only on SDR-based + * BTS with osmo-bts-trx where correct timing is easily achieved. */ + if (data_ind->sapi == GsmL1_Sapi_FacchF) + l1if_tch_rx_facch(trx, chan_nr, l1p_msg); + /* fill L1SAP header */ sap_msg = l1sap_msgb_alloc(data_ind->msgUnitParam.u8Size); l1sap = msgb_l1sap_prim(sap_msg); diff --git a/src/osmo-bts-sysmo/l1_if.h b/src/osmo-bts-sysmo/l1_if.h index 8691eef8..5b2da049 100644 --- a/src/osmo-bts-sysmo/l1_if.h +++ b/src/osmo-bts-sysmo/l1_if.h @@ -129,6 +129,8 @@ int l1if_tch_encode(struct gsm_lchan *lchan, uint8_t *data, uint8_t *len, const uint8_t *rtp_pl, unsigned int rtp_pl_len, uint32_t fn, bool use_cache, bool marker); int l1if_tch_rx(struct gsm_bts_trx *trx, uint8_t chan_nr, struct msgb *l1p_msg); +int l1if_tch_rx_facch(struct gsm_bts_trx *trx, uint8_t chan_nr, + struct msgb *l1p_msg); int l1if_tch_fill(struct gsm_lchan *lchan, uint8_t *l1_buffer); struct msgb *gen_empty_tch_msg(struct gsm_lchan *lchan, uint32_t fn); diff --git a/src/osmo-bts-sysmo/tch.c b/src/osmo-bts-sysmo/tch.c index 832991f8..3e7a1a12 100644 --- a/src/osmo-bts-sysmo/tch.c +++ b/src/osmo-bts-sysmo/tch.c @@ -623,6 +623,29 @@ err_payload_match: return -EINVAL; } +/*! \brief provide an RTP empty payload "tick" to upper layers upon FACCH */ +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; + + LOGPLCFN(lchan, 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); +} + struct msgb *gen_empty_tch_msg(struct gsm_lchan *lchan, uint32_t fn) { struct msgb *msg; |