[M] Change in osmo-bts[master]: HR1 codec: act on SID indication in RFC5993 RTP input

laforge has submitted this change. ( https://gerrit.osmocom.org/c/osmo-bts/+/33082 ) Change subject: HR1 codec: act on SID indication in RFC5993 RTP input ...................................................................... HR1 codec: act on SID indication in RFC5993 RTP input Suppose we receive RTP from the uplink of another BTS, and the UL-handling BTS has channel-decoded an HR1 frame which it deems (per GSM 06.41 section 6.1.1) to be a valid SID, even though it is not a perfect, error-free SID. How will this SID frame be represented in RFC 5993 transport? My reading of the RFC tells me that the UL-handling BTS will need to apply an operation like our osmo_hr_sid_reset() to the payload before sending it out in RTP - but because the text of the RFC does not explicitly address this scenario, others may have interpreted it differently. If we receive an RFC 5993 RTP payload in which FT is set to 2, indicating good SID, but the actual HR payload is not a perfect SID (the SID field is not all 1s), the only reasonable interpretation of such occurrence is that the sender of this payload was another BTS whose implementors interpreted the RFC as not requiring them to rejuvenate the SID codeword prior to RTP output. Therefore, let's treat such payloads as valid SID for our DTXd logic, and rejuvenate the SID codeword ourselves. Change-Id: Ife00de6220a8ca7cc180a61734497f1acb7f5b83 --- M include/osmo-bts/msg_utils.h M include/osmo-bts/rtp_input_preen.h M src/common/l1sap.c M src/common/rtp_input_preen.c 4 files changed, 52 insertions(+), 10 deletions(-) Approvals: Jenkins Builder: Verified pespin: Looks good to me, but someone else must approve laforge: Looks good to me, approved diff --git a/include/osmo-bts/msg_utils.h b/include/osmo-bts/msg_utils.h index 7ddbe88..fb8e11a 100644 --- a/include/osmo-bts/msg_utils.h +++ b/include/osmo-bts/msg_utils.h @@ -22,6 +22,9 @@ /* Access 3rd part of msgb control buffer */ #define rtpmsg_ts(x) ((x)->cb[2]) +/* Access 4th part of msgb control buffer */ +#define rtpmsg_is_rfc5993_sid(x) ((x)->cb[3]) + /** * Classification of OML message. ETSI for plain GSM 12.21 * messages and IPA/Osmo for manufacturer messages. diff --git a/include/osmo-bts/rtp_input_preen.h b/include/osmo-bts/rtp_input_preen.h index 822ee4a..744ae2a 100644 --- a/include/osmo-bts/rtp_input_preen.h +++ b/include/osmo-bts/rtp_input_preen.h @@ -17,4 +17,4 @@ enum pl_input_decision rtp_payload_input_preen(struct gsm_lchan *lchan, const uint8_t *rtp_pl, - unsigned rtp_pl_len); + unsigned rtp_pl_len, bool *rfc5993_sid_flag); diff --git a/src/common/l1sap.c b/src/common/l1sap.c index 75177a5..9d824e3 100644 --- a/src/common/l1sap.c +++ b/src/common/l1sap.c @@ -1314,9 +1314,17 @@ * directly coupled to the GSM 05.03 channel decoder, * and cannot be reconstructed downstream from frame * payload bits. The only kind of SID we can detect - * here is the perfect, error-free kind. */ - is_sid = osmo_hr_check_sid(msgb_l2(resp_msg), - msgb_l2len(resp_msg)); + * here is the perfect, error-free kind. However, + * if we received RFC 5993 payload and the sender + * told us it is valid SID, honor that indication + * and rejuvenate the SID codeword. */ + if (rtpmsg_is_rfc5993_sid(resp_msg)) { + is_sid = true; + osmo_hr_sid_reset(msgb_l2(resp_msg)); + } else { + is_sid = osmo_hr_check_sid(msgb_l2(resp_msg), + msgb_l2len(resp_msg)); + } } break; case GSM48_CMODE_SPEECH_EFR: @@ -2152,6 +2160,7 @@ { struct gsm_lchan *lchan = rs->priv; struct msgb *msg; + bool rfc5993_sid = false; /* if we're in loopback mode, we don't accept frames from the * RTP socket anymore */ @@ -2159,7 +2168,7 @@ return; /* initial preen */ - switch (rtp_payload_input_preen(lchan, rtp_pl, rtp_pl_len)) { + switch (rtp_payload_input_preen(lchan, rtp_pl, rtp_pl_len, &rfc5993_sid)) { case PL_DECISION_DROP: return; case PL_DECISION_ACCEPT: @@ -2184,6 +2193,8 @@ rtpmsg_seq(msg) = seq_number; /* Store RTP header Timestamp in control buffer */ rtpmsg_ts(msg) = timestamp; + /* Store RFC 5993 SID flag likewise */ + rtpmsg_is_rfc5993_sid(msg) = rfc5993_sid; /* make sure the queue doesn't get too long */ lchan_dl_tch_queue_enqueue(lchan, msg, 1); diff --git a/src/common/rtp_input_preen.c b/src/common/rtp_input_preen.c index dd526fd..c418e80 100644 --- a/src/common/rtp_input_preen.c +++ b/src/common/rtp_input_preen.c @@ -82,7 +82,8 @@ } static enum pl_input_decision -input_preen_hr(const uint8_t *rtp_pl, unsigned rtp_pl_len) +input_preen_hr(const uint8_t *rtp_pl, unsigned rtp_pl_len, + bool *rfc5993_sid_flag) { switch (rtp_pl_len) { case GSM_HR_BYTES: @@ -96,8 +97,7 @@ case 0x00: break; case 0x20: - /* TODO (next patch): signal this SID to the - * fr_hr_efr_dtxd_input() handler in l1sap. */ + *rfc5993_sid_flag = true; break; default: /* invalid payload */ @@ -113,7 +113,7 @@ enum pl_input_decision rtp_payload_input_preen(struct gsm_lchan *lchan, const uint8_t *rtp_pl, - unsigned rtp_pl_len) + unsigned rtp_pl_len, bool *rfc5993_sid_flag) { /* If rtp continuous-streaming is enabled, we shall emit RTP packets * with zero-length payloads as BFI markers. In a TrFO scenario such @@ -132,7 +132,7 @@ if (lchan->type == GSM_LCHAN_TCH_F) return input_preen_fr(rtp_pl, rtp_pl_len); else - return input_preen_hr(rtp_pl, rtp_pl_len); + return input_preen_hr(rtp_pl, rtp_pl_len, rfc5993_sid_flag); case GSM48_CMODE_SPEECH_EFR: return input_preen_efr(rtp_pl, rtp_pl_len); case GSM48_CMODE_SPEECH_AMR: -- To view, visit https://gerrit.osmocom.org/c/osmo-bts/+/33082 To unsubscribe, or for help writing mail filters, visit https://gerrit.osmocom.org/settings Gerrit-Project: osmo-bts Gerrit-Branch: master Gerrit-Change-Id: Ife00de6220a8ca7cc180a61734497f1acb7f5b83 Gerrit-Change-Number: 33082 Gerrit-PatchSet: 1 Gerrit-Owner: falconia <falcon(a)freecalypso.org> Gerrit-Reviewer: Jenkins Builder Gerrit-Reviewer: laforge <laforge(a)osmocom.org> Gerrit-Reviewer: pespin <pespin(a)sysmocom.de> Gerrit-MessageType: merged