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bts-{sysmo,oc2g,lc15}: Fix RTP of AMR SID_FIRST_P1 

When we receive a SID_FIRST_P1 frame from the PHY (during AMR/HR DTXu),
we must generate a SID frame on the RTP side.

The existing code
* ignored that the Amr_SidFirstP1 PHYIF message actually contains the
  RTP payload
* manually generated the same content using osmo_amr_rtp_enc()
* forgot to prefix that with the AMR CMR+TOC
* in the end, sent a completely broken (too short) AMR SID frame over RTP

Let's fix this by simply using the 7-byte RTP payload with CMR+TOC that
the PHY is providing to us.

Change-Id: I90479efcc002d497648a71e73847af54e6208358
Related: OS#5944
This commit is contained in:
Harald Welte 2023-03-27 21:05:10 +02:00
parent a563640f86
commit bb3ed23e71
3 changed files with 6 additions and 24 deletions
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10
src/osmo-bts-lc15/tch.c
View File

@ -360,7 +360,7 @@ int l1if_tch_rx(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;
uint8_t *payload, payload_type, payload_len, sid_first[9] = { 0 };
uint8_t *payload, payload_type, payload_len;
struct msgb *rmsg = NULL;
struct gsm_lchan *lchan = &trx->ts[L1SAP_CHAN2TS(chan_nr)].lchan[l1sap_chan2ss(chan_nr)];
@ -450,14 +450,8 @@ int l1if_tch_rx(struct gsm_bts_trx *trx, uint8_t chan_nr, struct msgb *l1p_msg)
rmsg = l1_to_rtppayload_efr(payload, payload_len, lchan);
break;
case GsmL1_TchPlType_Amr:
rmsg = l1_to_rtppayload_amr(payload, payload_len, lchan);
break;
case GsmL1_TchPlType_Amr_SidFirstP1:
memcpy(sid_first, payload, payload_len);
int len = osmo_amr_rtp_enc(sid_first, 0, AMR_SID, AMR_GOOD);
if (len < 0)
return 0;
rmsg = l1_to_rtppayload_amr(sid_first, len, lchan);
rmsg = l1_to_rtppayload_amr(payload, payload_len, lchan);
break;
}

10
src/osmo-bts-oc2g/tch.c
View File

@ -360,7 +360,7 @@ int l1if_tch_rx(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;
uint8_t *payload, payload_type, payload_len, sid_first[9] = { 0 };
uint8_t *payload, payload_type, payload_len;
struct msgb *rmsg = NULL;
struct gsm_lchan *lchan = &trx->ts[L1SAP_CHAN2TS(chan_nr)].lchan[l1sap_chan2ss(chan_nr)];
@ -460,14 +460,8 @@ int l1if_tch_rx(struct gsm_bts_trx *trx, uint8_t chan_nr, struct msgb *l1p_msg)
rmsg = l1_to_rtppayload_efr(payload, payload_len, lchan);
break;
case GsmL1_TchPlType_Amr:
rmsg = l1_to_rtppayload_amr(payload, payload_len, lchan);
break;
case GsmL1_TchPlType_Amr_SidFirstP1:
memcpy(sid_first, payload, payload_len);
int len = osmo_amr_rtp_enc(sid_first, 0, AMR_SID, AMR_GOOD);
if (len < 0)
return 0;
rmsg = l1_to_rtppayload_amr(sid_first, len, lchan);
rmsg = l1_to_rtppayload_amr(payload, payload_len, lchan);
break;
}

10
src/osmo-bts-sysmo/tch.c
View File

@ -505,7 +505,7 @@ int l1if_tch_rx(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;
uint8_t *payload, payload_type, payload_len, sid_first[9] = { 0 };
uint8_t *payload, payload_type, payload_len;
struct msgb *rmsg = NULL;
struct gsm_lchan *lchan = &trx->ts[L1SAP_CHAN2TS(chan_nr)].lchan[l1sap_chan2ss(chan_nr)];
@ -602,14 +602,8 @@ int l1if_tch_rx(struct gsm_bts_trx *trx, uint8_t chan_nr, struct msgb *l1p_msg)
break;
#endif
case GsmL1_TchPlType_Amr:
rmsg = l1_to_rtppayload_amr(payload, payload_len, lchan);
break;
case GsmL1_TchPlType_Amr_SidFirstP1:
memcpy(sid_first, payload, payload_len);
int len = osmo_amr_rtp_enc(sid_first, 0, AMR_SID, AMR_GOOD);
if (len < 0)
return 0;
rmsg = l1_to_rtppayload_amr(sid_first, len, lchan);
rmsg = l1_to_rtppayload_amr(payload, payload_len, lchan);
break;
/* FIXME: what about GsmL1_TchPlType_Amr_SidBad? not well documented. */
}