From 764b022fc69c4bb9816e12801186f8fa25f8dd72 Mon Sep 17 00:00:00 2001
From: Max <msuraev@sysmocom.de>
Date: Wed, 11 May 2016 17:33:17 +0200
Subject: [PATCH] Add function to make Uplink Measurement
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It assembles RSL Uplink Measurement IE according to 3GPP TS 08.58
§9.3.25. The function is based on lchan_build_rsl_ul_meas() from OsmoBTS
but optionally includes DTX information.

Change-Id: Ib37107bcc9909e5105ea711de42d3fb1db7e8d9e
Reviewed-on: https://gerrit.osmocom.org/44
Tested-by: Jenkins Builder
Reviewed-by: Harald Welte <laforge@gnumonks.org>
---
 include/osmocom/gsm/meas_rep.h |  4 ++++
 src/gsm/gsm_utils.c            | 20 ++++++++++++++++++++
 src/gsm/libosmogsm.map         |  2 ++
 3 files changed, 26 insertions(+)

diff --git a/include/osmocom/gsm/meas_rep.h b/include/osmocom/gsm/meas_rep.h
index 09c2c4f2d..90c981ddb 100644
--- a/include/osmocom/gsm/meas_rep.h
+++ b/include/osmocom/gsm/meas_rep.h
@@ -1,6 +1,7 @@
 #pragma once
 
 #include <stdint.h>
+#include <stdbool.h>
 
 /* RX Level and RX Quality */
 struct gsm_rx_lev_qual {
@@ -24,3 +25,6 @@ enum meas_rep_field {
 	MEAS_REP_UL_RXQUAL_FULL,
 	MEAS_REP_UL_RXQUAL_SUB,
 };
+
+size_t gsm0858_rsl_ul_meas_enc(struct gsm_meas_rep_unidir *mru, bool dtxd_used,
+			   uint8_t *buf);
diff --git a/src/gsm/gsm_utils.c b/src/gsm/gsm_utils.c
index 50029479d..7365ab7ce 100644
--- a/src/gsm/gsm_utils.c
+++ b/src/gsm/gsm_utils.c
@@ -66,11 +66,13 @@
 #include <osmocom/core/utils.h>
 #include <osmocom/core/bitvec.h>
 #include <osmocom/gsm/gsm_utils.h>
+#include <osmocom/gsm/meas_rep.h>
 #include <osmocom/gsm/protocol/gsm_04_08.h>
 
 #include <stdlib.h>
 #include <stdint.h>
 #include <string.h>
+#include <stdbool.h>
 #include <stdio.h>
 #include <errno.h>
 #include <ctype.h>
@@ -335,6 +337,24 @@ int gsm_7bit_encode_n_ussd(uint8_t *result, size_t n, const char *data, int *oct
 	return y;
 }
 
+/*! \brief Build the RSL uplink measurement IE (3GPP TS 08.58 § 9.3.25)
+ *  \param[in] mru Unidirectional measurement report structure
+ *  \param[in] dtxd_used Indicates if DTXd was used during measurement report
+ *             period
+ *  \param[out] buf Pre-allocated bufer for storing IE
+ *  \returns Number of bytes filled in buf
+ */
+size_t gsm0858_rsl_ul_meas_enc(struct gsm_meas_rep_unidir *mru, bool dtxd_used,
+			uint8_t *buf)
+{
+	buf[0] = dtxd_used ? (1 << 6) : 0;
+	buf[0] |= (mru->full.rx_lev & 0x3f);
+	buf[1] = (mru->sub.rx_lev & 0x3f);
+	buf[2] = ((mru->full.rx_qual & 7) << 3) | (mru->sub.rx_qual & 7);
+
+	return 3;
+}
+
 /* convert power class to dBm according to GSM TS 05.05 */
 unsigned int ms_class_gmsk_dbm(enum gsm_band band, int class)
 {
diff --git a/src/gsm/libosmogsm.map b/src/gsm/libosmogsm.map
index 834e5d668..1e2d3238b 100644
--- a/src/gsm/libosmogsm.map
+++ b/src/gsm/libosmogsm.map
@@ -92,6 +92,8 @@ gsm0808_create_reset;
 gsm0808_create_sapi_reject;
 gsm0808_prepend_dtap_header;
 
+gsm0858_rsl_ul_meas_enc;
+
 gsm338_get_sms_alphabet;
 
 gsm340_gen_oa;