sysinfo: Don't broadcast SI4 GPRS INDICATOR if PCU is disconnected

Depends: libosmocore.git I9d6ed06731ae15fdcef1a1f397d6ac2b7b1ca980
Change-Id: I1fd513ea03297918d15d4b28ed454f9b6dd6ebfa
Related: OS#3075

4 files changed, 56 insertions, 10 deletions

diff --git a/include/osmo-bts/bts.h b/include/osmo-bts/bts.h
index 4e496b59..9df7f087 100644
--- a/include/osmo-bts/bts.h
+++ b/include/osmo-bts/bts.h
@@ -158,10 +158,11 @@ struct gsm_bts {
 	/* offsets used while generating SI2quater */
 	size_t e_offset;
 	size_t u_offset;
-	/* decoded SI3 rest octets - *unmodified* as received from BSC */
+	/* decoded SI rest octets - *unmodified* as received from BSC */
 	struct osmo_gsm48_si_ro_info si3_ro_decoded;
-	/* is SI3 GPRS Indicator currently disabled due to lack of PCU connection? */
-	bool si3_gprs_ind_disabled;
+	struct osmo_gsm48_si_ro_info si4_ro_decoded;
+	/* is SI GPRS Indicator currently disabled due to lack of PCU connection? */
+	bool si_gprs_ind_disabled;
 
 	/* ip.access Unit ID's have Site/BTS/TRX layout */
 	union {
@@ -338,6 +339,7 @@ int bts_ccch_copy_msg(struct gsm_bts *bts, uint8_t *out_buf, struct gsm_time *gt
 int bts_supports_cipher(struct gsm_bts *bts, int rsl_cipher);
 uint8_t *bts_sysinfo_get(struct gsm_bts *bts, const struct gsm_time *g_time);
 void regenerate_si3_restoctets(struct gsm_bts *bts);
+void regenerate_si4_restoctets(struct gsm_bts *bts);
 uint8_t *lchan_sacch_get(struct gsm_lchan *lchan);
 int lchan_init_lapdm(struct gsm_lchan *lchan);
 
diff --git a/src/common/pcu_sock.c b/src/common/pcu_sock.c
index ee5f4a6b..550dd37d 100644
--- a/src/common/pcu_sock.c
+++ b/src/common/pcu_sock.c
@@ -746,8 +746,9 @@ static int pcu_rx_txt_ind(struct gsm_bts *bts,
 		oml_tx_failure_event_rep(&bts->gprs.cell.mo, NM_SEVER_CEASED, OSMO_EVT_PCU_VERS, txt->text);
 		osmo_strlcpy(bts->pcu_version, txt->text, MAX_VERSION_LENGTH);
 
-		/* patch SI3 to advertise GPRS, *if* the SI3 sent by BSC said so */
+		/* patch SI to advertise GPRS, *if* the SI sent by BSC said so */
 		regenerate_si3_restoctets(bts);
+		regenerate_si4_restoctets(bts);
 
 		if (GSM_BTS_HAS_SI(bts, SYSINFO_TYPE_13))
 			return pcu_tx_si13(bts, true);
@@ -899,6 +900,7 @@ static void pcu_sock_close(struct pcu_sock_state *state)
 
 	/* patch SI3 to remove GPRS indicator */
 	regenerate_si3_restoctets(bts);
+	regenerate_si4_restoctets(bts);
 
 	/* re-enable the generation of ACCEPT for new connections */
 	state->listen_bfd.when |= OSMO_FD_READ;
diff --git a/src/common/rsl.c b/src/common/rsl.c
index 919981dd..cb9c19b3 100644
--- a/src/common/rsl.c
+++ b/src/common/rsl.c
@@ -378,6 +378,15 @@ static int rsl_rx_bcch_info(struct gsm_bts_trx *trx, struct msgb *msg)
 			/* patch out GPRS indicator from binary if PCU is not connected; will be enabled
 			 * after PCU connects */
 			regenerate_si3_restoctets(bts);
+		} else if (SYSINFO_TYPE_4 == osmo_si) {
+			/* decode original SI4 Rest Octets as sent by BSC */
+			const uint8_t *si4_ro_buf = (uint8_t *) GSM_BTS_SI(bts, osmo_si);
+			si4_ro_buf += offsetof(struct gsm48_system_information_type_4, data);
+			osmo_gsm48_rest_octets_si4_decode(&bts->si4_ro_decoded, si4_ro_buf,
+							  GSM_MACBLOCK_LEN - offsetof(struct gsm48_system_information_type_4, data));
+			/* patch out GPRS indicator from binary if PCU is not connected; will be enabled
+			 * after PCU connects */
+			regenerate_si4_restoctets(bts);
 		}
 
 		if (SYSINFO_TYPE_13 == osmo_si)
diff --git a/src/common/sysinfo.c b/src/common/sysinfo.c
index d3efffcb..f3deb0dc 100644
--- a/src/common/sysinfo.c
+++ b/src/common/sysinfo.c
@@ -197,17 +197,50 @@ void regenerate_si3_restoctets(struct gsm_bts *bts)
 	/* Create a temporary copy and patch that, if no PCU is around */
 	si3ro_tmp = bts->si3_ro_decoded;
 	if (!pcu_connected()) {
-		if (!bts->si3_gprs_ind_disabled)
-			LOGP(DPCU, LOGL_NOTICE, "Disabling GPRS Indicator in SI3 (No PCU connected)\n");
-		bts->si3_gprs_ind_disabled = true;
+		if (!bts->si_gprs_ind_disabled)
+			LOGP(DPCU, LOGL_NOTICE, "Disabling GPRS Indicator in SI (No PCU connected)\n");
+		bts->si_gprs_ind_disabled = true;
 		si3ro_tmp.gprs_ind.present = 0;
 	} else {
-		if (bts->si3_gprs_ind_disabled)
-			LOGP(DPCU, LOGL_NOTICE, "Enabling GPRS Indicator in SI3 (PCU connected)\n");
-		bts->si3_gprs_ind_disabled = false;
+		if (bts->si_gprs_ind_disabled)
+			LOGP(DPCU, LOGL_NOTICE, "Enabling GPRS Indicator in SI (PCU connected)\n");
+		bts->si_gprs_ind_disabled = false;
 		si3ro_tmp.gprs_ind.present = 1; /* is a no-op as we copy from bts->si3_ro_decoded */
 	}
 
 	/* re-generate the binary SI3 rest octets */
 	osmo_gsm48_rest_octets_si3_encode(si3_buf + si3_size, &si3ro_tmp);
 }
+
+/* re-generate SI4 restoctets with GPRS indicator depending on the PCU socket connection state */
+void regenerate_si4_restoctets(struct gsm_bts *bts)
+{
+	uint8_t *si4_buf = GSM_BTS_SI(bts, SYSINFO_TYPE_4);
+	size_t si4_size = offsetof(struct gsm48_system_information_type_4, data);
+	struct osmo_gsm48_si_ro_info si4ro_tmp;
+
+	/* If BSC has never set SI4, there's nothing to patch */
+	if (!GSM_BTS_HAS_SI(bts, SYSINFO_TYPE_4))
+		return;
+
+	/* If SI4 from BSC doesn't have a GPRS indicator, we won't have anything to patch */
+	if (!bts->si4_ro_decoded.gprs_ind.present)
+		return;
+
+	/* Create a temporary copy and patch that, if no PCU is around */
+	si4ro_tmp = bts->si4_ro_decoded;
+	if (!pcu_connected()) {
+		if (!bts->si_gprs_ind_disabled)
+			LOGP(DPCU, LOGL_NOTICE, "Disabling GPRS Indicator in SI (No PCU connected)\n");
+		bts->si_gprs_ind_disabled = true;
+		si4ro_tmp.gprs_ind.present = 0;
+	} else {
+		if (bts->si_gprs_ind_disabled)
+			LOGP(DPCU, LOGL_NOTICE, "Enabling GPRS Indicator in SI (PCU connected)\n");
+		bts->si_gprs_ind_disabled = false;
+		si4ro_tmp.gprs_ind.present = 1; /* is a no-op as we copy from bts->si4_ro_decoded */
+	}
+
+	/* re-generate the binary SI4 rest octets */
+	osmo_gsm48_rest_octets_si4_encode(si4_buf + si4_size, &si4ro_tmp, GSM_MACBLOCK_LEN - si4_size);
+}