More comprehensive AMR handling

* parse AMR multirate config form 04.08 IE into easier format
* CMR, CMC and CMI on the L1 side are an _index_ into the current
  mode array
* Fix conversion of AMR SID frames from RTP -> L1

2 files changed, 153 insertions, 33 deletions

diff --git a/src/common/rsl.c b/src/common/rsl.c
index b9046f35..459ad2b3 100644
--- a/src/common/rsl.c
+++ b/src/common/rsl.c
@@ -121,6 +121,88 @@ static void lchan_tchmode_from_cmode(struct gsm_lchan *lchan,
  * support
  */
 
+static void log_mr_conf(int ss, int logl, const char *pfx,
+			struct amr_multirate_conf *amr_mrc)
+{
+	int i;
+
+	LOGP(ss, logl, "%s AMR MR Conf: num_modes=%u",
+		pfx, amr_mrc->num_modes);
+
+	for (i = 0; i < amr_mrc->num_modes; i++)
+		LOGPC(ss, logl, ", mode[%u] = %u/%u/%u",
+			i, amr_mrc->mode[i].mode, amr_mrc->mode[i].threshold,
+			amr_mrc->mode[i].hysteresis);
+	LOGPC(ss, logl, "\n");
+}
+
+
+/* parse a GSM 04.08 MultiRate Config IE (10.5.2.21aa) in a more
+ * comfortable internal data structure */
+static int parse_mr_conf(struct amr_multirate_conf *amr_mrc,
+			 const uint8_t *mr_conf, unsigned int len)
+{
+	uint8_t mr_version = mr_conf[0] >> 5;
+	uint8_t num_codecs = 0;
+	int i, j = 0;
+
+	if (mr_version != 1) {
+		LOGP(DRSL, LOGL_ERROR, "AMR Multirate Version %u unknonw\n",
+			mr_version);
+		goto ret_einval;
+	}
+
+	/* check number of active codecs */
+	for (i = 0; i < 8; i++) {
+		if (mr_conf[1] & (1 << i))
+			num_codecs++;
+	}
+
+	/* check for minimum length */
+	if (num_codecs == 0 ||
+	    (num_codecs == 1 && len < 2) ||
+	    (num_codecs == 2 && len < 4) ||
+	    (num_codecs == 3 && len < 5) ||
+	    (num_codecs == 4 && len < 6) ||
+	    (num_codecs > 4)) {
+		LOGP(DRSL, LOGL_ERROR, "AMR Multirate with %u modes len=%u "
+		     "not possible\n", num_codecs, len);
+		goto ret_einval;
+	}
+
+	/* copy the first two octets of the IE */
+	amr_mrc->gsm48_ie[0] = mr_conf[0];
+	amr_mrc->gsm48_ie[1] = mr_conf[1];
+
+	amr_mrc->num_modes = num_codecs;
+
+	for (i = 0; i < 8; i++) {
+		if (mr_conf[1] & (1 << i)) {
+			amr_mrc->mode[j++].mode = i;
+		}
+	}
+
+	if (num_codecs >= 2) {
+		amr_mrc->mode[0].threshold = mr_conf[1] & 0x3F;
+		amr_mrc->mode[0].hysteresis = mr_conf[2] >> 4;
+	}
+	if (num_codecs >= 3) {
+		amr_mrc->mode[1].threshold =
+			((mr_conf[2] & 0xF) << 2) | (mr_conf[3] >> 6);
+		amr_mrc->mode[1].hysteresis = (mr_conf[3] >> 2) & 0x7;
+	}
+	if (num_codecs >= 4) {
+		amr_mrc->mode[3].threshold =
+			((mr_conf[3] & 0x3) << 4) | (mr_conf[4] >> 4);
+		amr_mrc->mode[3].hysteresis = mr_conf[4] & 0xF;
+	}
+
+	return num_codecs;
+
+ret_einval:
+	return -EINVAL;
+}
+
 
 #warning merge lchan_lookup with OpenBSC
 /* determine logical channel based on TRX and channel number IE */
@@ -683,6 +765,10 @@ static int rsl_rx_chan_activ(struct msgb *msg)
 		}
 		memcpy(&lchan->mr_conf, TLVP_VAL(&tp, RSL_IE_MR_CONFIG),
 		       TLVP_LEN(&tp, RSL_IE_MR_CONFIG));
+		parse_mr_conf(&lchan->tch.amr_mr, TLVP_VAL(&tp, RSL_IE_MR_CONFIG),
+				TLVP_LEN(&tp, RSL_IE_MR_CONFIG));
+		log_mr_conf(DRTP, LOGL_DEBUG, gsm_lchan_name(lchan),
+			    &lchan->tch.amr_mr);
 	}
 	/* 9.3.53 MultiRate Control */
 	/* 9.3.54 Supported Codec Types */
@@ -917,7 +1003,11 @@ static int rsl_rx_mode_modif(struct msgb *msg)
 			return rsl_tx_error_report(msg->trx, RSL_ERR_IE_CONTENT);
 		}
 		memcpy(&lchan->mr_conf, TLVP_VAL(&tp, RSL_IE_MR_CONFIG),
-		       TLVP_LEN(&tp, RSL_IE_MR_CONFIG));
+			TLVP_LEN(&tp, RSL_IE_MR_CONFIG));
+		parse_mr_conf(&lchan->tch.amr_mr, TLVP_VAL(&tp, RSL_IE_MR_CONFIG),
+				TLVP_LEN(&tp, RSL_IE_MR_CONFIG));
+		log_mr_conf(DRTP, LOGL_DEBUG, gsm_lchan_name(lchan),
+			    &lchan->tch.amr_mr);
 	}
 	/* 9.3.53 MultiRate Control */
 	/* 9.3.54 Supported Codec Types */
diff --git a/src/osmo-bts-sysmo/tch.c b/src/osmo-bts-sysmo/tch.c
index dd2ae32d..68ad0ce4 100644
--- a/src/osmo-bts-sysmo/tch.c
+++ b/src/osmo-bts-sysmo/tch.c
@@ -65,9 +65,9 @@ void osmo_nibble_shift_right(uint8_t *out, const uint8_t *in,
 	/* shift the last nibble, in case there's an odd count */
 	i = num_whole_bytes;
 	if (num_nibbles & 1)
-		out[i] = (in[i-1] & 0xF) << 4;
-	else
 		out[i] = ((in[i-1] & 0xF) << 4) | (in[i] >> 4);
+	else
+		out[i] = (in[i-1] & 0xF) << 4;
 }
 
 
@@ -201,29 +201,30 @@ static int rtppayload_to_l1_hr(uint8_t *l1_payload, uint8_t *rtp_payload,
 #define AMR_CMR_NONE	0xF
 
 static struct msgb *l1_to_rtppayload_amr(uint8_t *l1_payload, uint8_t payload_len,
-					 uint8_t active_codec_set)
+					 struct amr_multirate_conf *amr_mrc)
 {
 	struct msgb *msg = msgb_alloc_headroom(1024, 128, "L1C-to-RTP");
 	uint8_t *cur;
+	u_int8_t cmr;
 	uint8_t ft = l1_payload[2] & 0xF;
-	uint8_t cmr = l1_payload[1];
+	uint8_t cmr_idx = l1_payload[1];
 	uint8_t amr_if2_len = payload_len - 2;
 
-#warning Only use CMR when it actually appears according to TDMA time
 #if 0
-	/* CMR can never be > 7 */
-	if (cmr > 7)
+	/* CMR == Unset means CMR was not transmitted at this TDMA */
+	if (cmr_idx >= GsmL1_AmrCodecMode_Unset)
 		cmr = AMR_CMR_NONE;
-	else {
+	else if (cmr_idx >= amr_mrc->num_modes) {
 		/* Make sure the CMR of the phone is in the active codec set */
-		if (!(active_codec_set & (1 << cmr))) {
-			LOGP(DL1C, LOGL_NOTICE, "L1->RTP: overriding CMR %u\n", cmr);
-			cmr = AMR_CMR_NONE;
-		}
+		LOGP(DL1C, LOGL_NOTICE, "L1->RTP: overriding CMR IDX %u\n", cmr_idx);
+		cmr = AMR_CMR_NONE;
+	} else {
+		cmr = amr_mrc->mode[cmr_idx].mode;
 	}
 #else
 	cmr = AMR_CMR_NONE;
 #endif
+
 	/* RFC 3267  4.4.1 Payload Header */
 	msgb_put_u8(msg, (cmr << 4));
 
@@ -245,6 +246,16 @@ enum amr_frame_type {
 	AMR_FT_SID_AMR	= 8,
 };
 
+int get_amr_mode_idx(const struct amr_multirate_conf *amr_mrc, uint8_t cmi)
+{
+	unsigned int i;
+	for (i = 0; i < amr_mrc->num_modes; i++) {
+		if (amr_mrc->mode[i].mode == cmi)
+			return i;
+	}
+	return -EINVAL;
+}
+
 /*! \brief convert AMR from RTP payload to L1 format
  *  \param[out] l1_payload payload part of L1 buffer
  *  \param[in] rtp_payload pointer to RTP payload data
@@ -252,47 +263,67 @@ enum amr_frame_type {
  *  \returns number of \a l1_payload bytes filled
  */
 static int rtppayload_to_l1_amr(uint8_t *l1_payload, uint8_t *rtp_payload,
-				uint8_t payload_len, const uint8_t active_codec_set)
+				uint8_t payload_len,
+				struct amr_multirate_conf *amr_mrc)
 {
 	uint8_t ft = (rtp_payload[1] >> 3) & 0xf;
 	uint8_t cmr = rtp_payload[0] >> 4;
-	uint8_t *l1_cmi = l1_payload;
-	uint8_t *l1_cmr = l1_payload+1;
+	uint8_t cmi, sti;
+	uint8_t *l1_cmi_idx = l1_payload;
+	uint8_t *l1_cmr_idx = l1_payload+1;
 	uint8_t amr_if2_core_len = payload_len - 2;
+	int rc;
 
 	/* step1: shift everything right one nibble; make space for FT */
-	osmo_nibble_shift_right(l1_payload+2, rtp_payload+2, amr_if2_core_len*2 -1);
+	osmo_nibble_shift_right(l1_payload+2, rtp_payload+2, amr_if2_core_len*2);
 	/* step2: reverse the bit-order within every byte of the IF2
 	 * core frame contained in the RTP payload */
-	osmo_revbytebits_buf(l1_payload+2, amr_if2_core_len);
+	osmo_revbytebits_buf(l1_payload+2, amr_if2_core_len+1);
 
 	/* CMI in downlink tells the L1 encoder which encoding function
 	 * it will use, so we have to use the frame type */
 	switch (ft) {
 	case 0: case 1: case 2: case 3:
 	case 4: case 5: case 6: case 7:
-		*l1_cmi = ft;
+		cmi = ft;
+		LOGP(DL1C, LOGL_ERROR, "SPEECH frame with CMI %u\n", cmi);
 		break;
 	case AMR_FT_SID_AMR:
-		/* extract the mode indiciation from last 3 bits of
-		 * 39 bit SID frame */
-		*l1_cmi = *(l1_payload+2+4) >> 4;
+		/* extract the mode indiciation from last bits of
+		 * 39 bit SID frame (Table 6 / 26.101) */
+		cmi = (rtp_payload[2+4] >> 1) & 0x7;
+		sti = rtp_payload[2+4] & 0x10;
+		LOGP(DL1C, LOGL_ERROR, "SID %s frame with CMI %u\n",
+		     sti ? "UPDATE" : "FIRST", cmi);
 		break;
 	default:
 		LOGP(DL1C, LOGL_ERROR, "unsupported AMR FT 0x%02x\n", ft);
+		return -EINVAL;
 		break;
 	}
 
+	rc = get_amr_mode_idx(amr_mrc, cmi);
+	if (rc < 0) {
+		LOGP(DL1C, LOGL_ERROR, "AMR CMI %u not part of AMR MR set\n",
+			cmi);
+		*l1_cmi_idx = 0;
+	} else
+		*l1_cmi_idx = rc;
+
 	/* Codec Mode Request is in upper 4 bits of RTP payload header,
 	 * and we simply copy the CMR into the CMC */
-	if (cmr == 0xF)
-		*l1_cmr = 2;
-	else if (!(active_codec_set & (1 << cmr))) {
+	if (cmr == 0xF) {
 		/* FIXME: we need some state about the last codec mode */
-		LOGP(DL1C, LOGL_NOTICE, "RTP->L1: overriding CMR %u\n", cmr);
-		*l1_cmr = 2;
-	} else
-		*l1_cmr = cmr;
+		*l1_cmr_idx = 0;
+	} else {
+		rc = get_amr_mode_idx(amr_mrc, cmr);
+		if (rc < 0) {
+			/* FIXME: we need some state about the last codec mode */
+			LOGP(DL1C, LOGL_NOTICE, "RTP->L1: overriding CMR %u\n", cmr);
+			*l1_cmr_idx = 0;
+		} else
+			*l1_cmr_idx = rc;
+	}
 #if 0
 	/* check for bad quality indication */
 	if (rtp_payload[1] & AMR_TOC_QBIT) {
@@ -339,7 +370,6 @@ void bts_model_rtp_rx_cb(struct osmo_rtp_socket *rs, uint8_t *rtp_pl,
 	GsmL1_MsgUnitParam_t *msu_param = &data_req->msgUnitParam;
 	uint8_t *payload_type = &msu_param->u8Buffer[0];
 	uint8_t *l1_payload = &msu_param->u8Buffer[1];
-	uint8_t *mr_conf = &lchan->mr_conf;
 	int rc;
 
 	DEBUGP(DL1C, "%s RTP IN: %s\n", gsm_lchan_name(lchan),
@@ -366,7 +396,7 @@ void bts_model_rtp_rx_cb(struct osmo_rtp_socket *rs, uint8_t *rtp_pl,
 	case GSM48_CMODE_SPEECH_AMR:
 		*payload_type = GsmL1_TchPlType_Amr;
 		rc = rtppayload_to_l1_amr(l1_payload, rtp_pl,
-					  rtp_pl_len, mr_conf[1]);
+					  rtp_pl_len, &lchan->tch.amr_mr);
 		break;
 	default:
 		/* we don't support CSD modes */
@@ -416,7 +446,6 @@ int l1if_tch_rx(struct gsm_lchan *lchan, struct msgb *l1p_msg)
 	GsmL1_PhDataInd_t *data_ind = &l1p->u.phDataInd;
 	uint8_t payload_type = data_ind->msgUnitParam.u8Buffer[0];
 	uint8_t *payload = data_ind->msgUnitParam.u8Buffer + 1;
-	uint8_t *mr_conf = &lchan->mr_conf;
 	uint8_t payload_len;
 	struct msgb *rmsg = NULL;
 
@@ -467,7 +496,8 @@ int l1if_tch_rx(struct gsm_lchan *lchan, struct msgb *l1p_msg)
 		break;
 #endif
 	case GsmL1_TchPlType_Amr:
-		rmsg = l1_to_rtppayload_amr(payload, payload_len, mr_conf[1]);
+		rmsg = l1_to_rtppayload_amr(payload, payload_len,
+					    &lchan->tch.amr_mr);
 		break;
 	}