Change in libosmocore[master]: Set DTX in Cell Options

[gerrit-no-reply at lists.osmocom.org]

>From Max <msuraev at sysmocom.de>:

Max has uploaded a new change for review.

  https://gerrit.osmocom.org/39

Change subject: Set DTX in Cell Options
......................................................................

Set DTX in Cell Options

* rename field of struct gsm48_cell_options to better match the spec
* add comments with spec references
* add function for setting DTX in cell options struct
* add necessary enum type

Change-Id: I5a8924f57669c951b2e51b663d95f1d360062a54
---
M include/osmocom/gsm/protocol/gsm_04_08.h
M src/gsm/gsm48.c
M src/gsm/libosmogsm.map
3 files changed, 61 insertions(+), 2 deletions(-)


  git pull ssh://gerrit.osmocom.org:29418/libosmocore refs/changes/39/39/1

diff --git a/include/osmocom/gsm/protocol/gsm_04_08.h b/include/osmocom/gsm/protocol/gsm_04_08.h
index 3282bc1..5ee387b 100644
--- a/include/osmocom/gsm/protocol/gsm_04_08.h
+++ b/include/osmocom/gsm/protocol/gsm_04_08.h
@@ -1,6 +1,7 @@
 #pragma once
 
 #include <stdint.h>
+#include <stdbool.h>
 
 #include <osmocom/core/utils.h>
 
@@ -469,11 +470,20 @@
 	uint8_t t3212;
 } __attribute__ ((packed));
 
+enum gsm48_dtx_mode {
+	GSM48_MAY_USE,
+	GSM48_SHALL_USE,
+	GSM48_SHALL_NOT
+};
+
+/* Cell Options for SI6, SACCH (10.5.2.3a.2) or SI3, BCCH (Table 10.5.2.3.1),
+   3GPP TS 44.018 */
 struct gsm48_cell_options {
 	uint8_t radio_link_timeout:4,
 		 dtx:2,
 		 pwrc:1,
-		 spare:1;
+	/* either DN-IND or top bit of DTX IND */
+		 d:1;
 } __attribute__ ((packed));
 
 /* Section 9.2.9 CM service request */
@@ -827,6 +837,9 @@
 	}
 }
 
+void gsm48_set_dtx(struct gsm48_cell_options *op, enum gsm48_dtx_mode full,
+		   enum gsm48_dtx_mode half, bool is_bcch);
+
 #define gsm48_hdr_msg_type gsm48_hdr_msg_type_r99
 
 /* Section 10.4 */
diff --git a/src/gsm/gsm48.c b/src/gsm/gsm48.c
index ab62605..2a30b3c 100644
--- a/src/gsm/gsm48.c
+++ b/src/gsm/gsm48.c
@@ -25,7 +25,7 @@
 #include <stdint.h>
 #include <stdio.h>
 #include <string.h>
-
+#include <stdbool.h>
 #include <arpa/inet.h>
 
 #include <osmocom/core/utils.h>
@@ -358,6 +358,50 @@
 	return 0;
 }
 
+/*! \brief Set DTX mode in Cell Options IE (3GPP TS 44.018)
+ *  \param[in] op Cell Options structure in which DTX parameters will be set
+ *  \param[in] full Mode for full-rate channels
+ *  \param[in] half Mode for half-rate channels
+ *  \param[in] is_bcch Indicates if we should use 10.5.2.3.1 instead of
+ *             10.5.2.3a.2
+ *
+ * There is no space for separate DTX settings for Full and Half rate channels
+ * in BCCH - in this case full setting is used for both and half parameter is
+ * ignored.
+ */
+void gsm48_set_dtx(struct gsm48_cell_options *op, enum gsm48_dtx_mode full,
+		   enum gsm48_dtx_mode half, bool is_bcch)
+{
+	if (is_bcch) {
+		switch (full) {
+		case GSM48_MAY_USE:
+			op->dtx = 0;
+			return;
+		case GSM48_SHALL_USE:
+			op->dtx = 1;
+			return;
+		case GSM48_SHALL_NOT:
+			op->dtx = 2;
+			return;
+		}
+	} else {
+		switch (full) {
+		case GSM48_MAY_USE:
+			op->dtx = (half == GSM48_SHALL_USE) ? 3 : 0;
+			op->d =   (half == GSM48_SHALL_NOT) ? 0 : 1;
+			return;
+		case GSM48_SHALL_USE:
+			op->dtx = (half == GSM48_MAY_USE) ? 3 : 1;
+			op->d =   (half == GSM48_SHALL_USE) ? 1 : 0;
+			return;
+		case GSM48_SHALL_NOT:
+			op->dtx = 2;
+			op->d =   (half == GSM48_SHALL_USE) ? 1 : 0;
+			return;
+		}
+	}
+}
+
 int gsm48_generate_mid_from_tmsi(uint8_t *buf, uint32_t tmsi)
 {
 	uint32_t tmsi_be = htonl(tmsi);
diff --git a/src/gsm/libosmogsm.map b/src/gsm/libosmogsm.map
index e0d9dcb..834e5d6 100644
--- a/src/gsm/libosmogsm.map
+++ b/src/gsm/libosmogsm.map
@@ -162,6 +162,8 @@
 gsm48_number_of_paging_subchannels;
 gsm48_parse_ra;
 gsm48_rr_att_tlvdef;
+gsm48_set_dtx;
+gsm48_dtx_mode;
 gsm48_mi_type_name;
 gsm48_mcc_mnc_to_bcd;
 gsm48_mcc_mnc_from_bcd;

-- 
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Gerrit-MessageType: newchange
Gerrit-Change-Id: I5a8924f57669c951b2e51b663d95f1d360062a54
Gerrit-PatchSet: 1
Gerrit-Project: libosmocore
Gerrit-Branch: master
Gerrit-Owner: Max <msuraev at sysmocom.de>