Change in osmo-bsc[master]: Add VTY option to avoid sending empty Full BCCH Info for disabled SI

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Harald Welte gerrit-no-reply at lists.osmocom.org
Fri Dec 14 20:06:37 UTC 2018 

Harald Welte has submitted this change and it was merged. ( https://gerrit.osmocom.org/12133 )

Change subject: Add VTY option to avoid sending empty Full BCCH Info for disabled SI
......................................................................

Add VTY option to avoid sending empty Full BCCH Info for disabled SI

According to 3GPP TS 08.58 §8.5.1 BCCH INFORMATION:
"If the Full BCCH information element is not included this indicates that
transmission of the indicated SYSTEM INFORMATION message shall be stopped."

However, some ipaccess nanoBTS firmware versions are known to not support
some SI elements and also to dislike receiving BCCH Information for those SI,
even if received with empty BCCH Information meaning they should not be used.

Upon receival of this kind of message, nanoBTS sends a Failure Report
with following text:
Type=processing failure, Severity=critical failure, Probable cause=Manufacturer specific values: Fatal software error, Additional Text=l2_bch.c:1149
****
** l2_bch.c#1149:BCHbcchSItypeValid( prim_p->infoType )
** IPA_SW_FATAL_ERROR
** In task "TRX Proc:L2_BCH" @ (325).
****

This kind of issue only appears with some fw versions, since it's known
to work fine in other ones, so let's not disable this kind of mesage by
default on all BTs of type "nanobts".

Instead, add a VTY command that allows disabling this kind of message in
order to be able to operate those nanoBTS units.

Fixes: OS#3707
Change-Id: Idec1daabc21de4eea5c55edd1dbb0e0775720fc7
---
M include/osmocom/bsc/gsm_data.h
M src/osmo-bsc/bsc_init.c
M src/osmo-bsc/bsc_vty.c
M src/osmo-bsc/gsm_data.c
4 files changed, 50 insertions(+), 6 deletions(-)

Approvals:
  Harald Welte: Looks good to me, approved
  Stefan Sperling: Looks good to me, but someone else must approve
  Jenkins Builder: Verified



diff --git a/include/osmocom/bsc/gsm_data.h b/include/osmocom/bsc/gsm_data.h
index e57da55..738bad3 100644
--- a/include/osmocom/bsc/gsm_data.h
+++ b/include/osmocom/bsc/gsm_data.h
@@ -981,6 +981,9 @@
 	/* offsets used while generating SI2quater */
 	size_t e_offset;
 	size_t u_offset;
+	/* 3GPP TS 08.58 §8.5.1 BCCH INFORMATION. Some nanoBTS fail upon
+	 * receival of empty SI disabling unsupported SI. see OS#3707. */
+	bool si_unused_send_empty;
 
 	/* ip.accesss Unit ID's have Site/BTS/TRX layout */
 	union {
diff --git a/src/osmo-bsc/bsc_init.c b/src/osmo-bsc/bsc_init.c
index 2f44b20..7d29d4f 100644
--- a/src/osmo-bsc/bsc_init.c
+++ b/src/osmo-bsc/bsc_init.c
@@ -173,12 +173,16 @@
 
 	for (n = 0; n < n_si; n++) {
 		i = gen_si[n];
-		/* if we don't currently have this SI, we send a zero-length
-		 * RSL BCCH FILLING / SACCH FILLING * in order to deactivate
-		 * the SI, in case it might have previously been active */
-		if (!GSM_BTS_HAS_SI(bts, i))
-			rc = rsl_si(trx, i, 0);
-		else
+		/* 3GPP TS 08.58 §8.5.1 BCCH INFORMATION. If we don't currently
+		 * have this SI, we send a zero-length RSL BCCH FILLING /
+		 * SACCH FILLING in order to deactivate the SI, in case it
+		 * might have previously been active */
+		if (!GSM_BTS_HAS_SI(bts, i)) {
+			if (bts->si_unused_send_empty)
+				rc = rsl_si(trx, i, 0);
+			else
+				rc = 0; /* some nanoBTS fw don't like receiving empty unsupported SI */
+		} else
 			rc = rsl_si(trx, i, si_len[i]);
 		if (rc < 0)
 			return rc;
diff --git a/src/osmo-bsc/bsc_vty.c b/src/osmo-bsc/bsc_vty.c
index 8c7d8e1..032305e 100644
--- a/src/osmo-bsc/bsc_vty.c
+++ b/src/osmo-bsc/bsc_vty.c
@@ -874,6 +874,8 @@
 	}
 	vty_out(vty, "  access-control-class-ramping-step-size %u%s", acc_ramp_get_step_size(&bts->acc_ramp),
 		VTY_NEWLINE);
+	if (!bts->si_unused_send_empty)
+		vty_out(vty, "  no system-information unused-send-empty%s", VTY_NEWLINE);
 	for (i = SYSINFO_TYPE_1; i < _MAX_SYSINFO_TYPE; i++) {
 		if (bts->si_mode_static & (1 << i)) {
 			vty_out(vty, "  system-information %s mode static%s",
@@ -3087,6 +3089,38 @@
 	return CMD_SUCCESS;
 }
 
+DEFUN(cfg_bts_si_unused_send_empty, cfg_bts_si_unused_send_empty_cmd,
+	"system-information unused-send-empty",
+	SI_TEXT
+	"Send BCCH Info with empty 'Full BCCH Info' TLV to notify disabled SI. "
+	"Some nanoBTS fw versions are known to fail upon receival of these messages.\n")
+{
+	struct gsm_bts *bts = vty->index;
+
+	bts->si_unused_send_empty = true;
+
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_bts_no_si_unused_send_empty, cfg_bts_no_si_unused_send_empty_cmd,
+	"no system-information unused-send-empty",
+	NO_STR SI_TEXT
+	"Avoid sending BCCH Info with empty 'Full BCCH Info' TLV to notify disabled SI. "
+	"Some nanoBTS fw versions are known to fail upon receival of these messages.\n")
+{
+	struct gsm_bts *bts = vty->index;
+
+	if (!is_ipaccess_bts(bts) || is_sysmobts_v2(bts)) {
+		vty_out(vty, "This command is only intended for ipaccess nanoBTS. See OS#3707.%s",
+			VTY_NEWLINE);
+		return CMD_WARNING;
+	}
+
+	bts->si_unused_send_empty = false;
+
+	return CMD_SUCCESS;
+}
+
 DEFUN(cfg_bts_early_cm, cfg_bts_early_cm_cmd,
 	"early-classmark-sending (allowed|forbidden)",
 	"Early Classmark Sending\n"
@@ -5132,6 +5166,8 @@
 	install_element(BTS_NODE, &cfg_bts_pag_free_cmd);
 	install_element(BTS_NODE, &cfg_bts_si_mode_cmd);
 	install_element(BTS_NODE, &cfg_bts_si_static_cmd);
+	install_element(BTS_NODE, &cfg_bts_si_unused_send_empty_cmd);
+	install_element(BTS_NODE, &cfg_bts_no_si_unused_send_empty_cmd);
 	install_element(BTS_NODE, &cfg_bts_early_cm_cmd);
 	install_element(BTS_NODE, &cfg_bts_early_cm_3g_cmd);
 	install_element(BTS_NODE, &cfg_bts_neigh_mode_cmd);
diff --git a/src/osmo-bsc/gsm_data.c b/src/osmo-bsc/gsm_data.c
index 0f76a27..7eee918 100644
--- a/src/osmo-bsc/gsm_data.c
+++ b/src/osmo-bsc/gsm_data.c
@@ -856,6 +856,7 @@
 	bts->gprs.ctrl_ack_type_use_block = true; /* use RLC/MAC control block */
 	bts->neigh_list_manual_mode = NL_MODE_AUTOMATIC;
 	bts->early_classmark_allowed_3g = true; /* 3g Early Classmark Sending controlled by bts->early_classmark_allowed param */
+	bts->si_unused_send_empty = true;
 	bts->si_common.cell_sel_par.cell_resel_hyst = 2; /* 4 dB */
 	bts->si_common.cell_sel_par.rxlev_acc_min = 0;
 	bts->si_common.si2quater_neigh_list.arfcn = bts->si_common.data.earfcn_list;

-- 
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Gerrit-Project: osmo-bsc
Gerrit-Branch: master
Gerrit-MessageType: merged
Gerrit-Change-Id: Idec1daabc21de4eea5c55edd1dbb0e0775720fc7
Gerrit-Change-Number: 12133
Gerrit-PatchSet: 4
Gerrit-Owner: Pau Espin Pedrol <pespin at sysmocom.de>
Gerrit-Reviewer: Harald Welte <laforge at gnumonks.org>
Gerrit-Reviewer: Jenkins Builder (1000002)
Gerrit-Reviewer: Pau Espin Pedrol <pespin at sysmocom.de>
Gerrit-Reviewer: Stefan Sperling <stsp at stsp.name>
Gerrit-Reviewer: Vadim Yanitskiy <axilirator at gmail.com>
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