sccp: Notify users of point code available/unavailable

* add N-PCSTATE.ind and N-STATE.ind definitions to SCCP user SAP
* add minimal SCMG (SCCP Management) and LBCS (Local Broadcast)
* generate MTP-PAUSE.ind/MTP-RESUME.ind based on received xUA DUNA/DAVA
* generate N-PCSTATE.ind towards the local SCCP users

Change-Id: Idb799f7d7ab329ad12f07b7cbe6336da0891ae92
Related: OS#2623, OS#3403, OS#4701

6 files changed, 233 insertions, 1 deletions

diff --git a/include/osmocom/sigtran/sccp_sap.h b/include/osmocom/sigtran/sccp_sap.h
index de9b24c..d741644 100644
--- a/include/osmocom/sigtran/sccp_sap.h
+++ b/include/osmocom/sigtran/sccp_sap.h
@@ -137,6 +137,21 @@ enum osmo_sccp_ssn {
 	OSMO_SCCP_SSN_BSSAP		= 254,
 };
 
+/* Q.711 6.3.2.2.5 Signalling point status */
+enum osmo_sccp_sp_status {
+	OSMO_SCCP_SP_S_INACCESSIBLE	= 1,
+	OSMO_SCCP_SP_S_CONGESTED	= 2,
+	OSMO_SCCP_SP_S_ACCESSIBLE	= 3,
+};
+/* Q.711 6.3.2.2.6 Remote SCCP status */
+enum osmo_sccp_rem_sccp_status {
+	OSMO_SCCP_REM_SCCP_S_AVAILABLE 			= 1,
+	OSMO_SCCP_REM_SCCP_S_UNAVAILABLE_UNKNOWN	= 2,
+	OSMO_SCCP_REM_SCCP_S_UNEQUIPPED			= 3,
+	OSMO_SCCP_REM_SCCP_S_INACCESSIBLE		= 4,
+	OSMO_SCCP_REM_SCCP_S_CONGESTED			= 5,
+};
+
 /* legacy shim for name change */
 #define OSMO_SCCP_SSN_SMLC_BSSAP OSMO_SCCP_SSN_SMLC_BSSAP_LE
 
@@ -226,6 +241,22 @@ struct osmo_scu_notice_param {
 	/* user data */
 };
 
+/* OSMO_SCU_PRIM_N_STATE */
+struct osmo_scu_state_param {
+	uint32_t affected_pc;
+	uint32_t affected_ssn;
+	bool user_in_service; /* true: UIS; false: UOS */
+	uint32_t ssn_multiplicity_ind;
+};
+
+/* OSMO_ASCU_PRIM_N_PCSTATE */
+struct osmo_scu_pcstate_param {
+	uint32_t affected_pc;
+	uint32_t restricted_importance_level;
+	enum osmo_sccp_sp_status sp_status;
+	enum osmo_sccp_rem_sccp_status remote_sccp_status;
+};
+
 struct osmo_scu_prim {
 	struct osmo_prim_hdr oph;
 	union {
@@ -235,6 +266,8 @@ struct osmo_scu_prim {
 		struct osmo_scu_reset_param reset;
 		struct osmo_scu_unitdata_param unitdata;
 		struct osmo_scu_notice_param notice;
+		struct osmo_scu_state_param state;
+		struct osmo_scu_pcstate_param pcstate;
 	} u;
 };
 
diff --git a/src/Makefile.am b/src/Makefile.am
index 41d2a8d..4558810 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -29,7 +29,8 @@ LIBVERSION=5:0:0
 
 libosmo_sigtran_la_SOURCES = sccp_sap.c sua.c m3ua.c xua_msg.c sccp_helpers.c \
 			     sccp2sua.c sccp_scrc.c sccp_sclc.c sccp_scoc.c \
-			     sccp_user.c sccp_types.c xua_rkm.c xua_shared.c xua_default_lm_fsm.c \
+			     sccp_user.c sccp_types.c sccp_lbcs.c sccp_scmg.c \
+			     xua_rkm.c xua_shared.c xua_default_lm_fsm.c \
 			     osmo_ss7.c osmo_ss7_hmrt.c xua_asp_fsm.c xua_as_fsm.c \
 			     xua_snm.c osmo_ss7_vty.c sccp_vty.c ipa.c
 libosmo_sigtran_la_LDFLAGS = -version-info $(LIBVERSION) -no-undefined -export-symbols-regex '^osmo_'
diff --git a/src/sccp_internal.h b/src/sccp_internal.h
index 98f6d37..6ad7ee3 100644
--- a/src/sccp_internal.h
+++ b/src/sccp_internal.h
@@ -129,3 +129,13 @@ const struct osmo_sccp_timer_val *osmo_sccp_timer_get(const struct osmo_sccp_ins
 						      bool default_if_unset);
 
 void osmo_sccp_vty_write_cs7_node(struct vty *vty, const char *indent, struct osmo_sccp_instance *inst);
+
+/* Local Broadcast (LBCS) */
+void sccp_lbcs_local_bcast_pcstate(struct osmo_sccp_instance *inst,
+				   const struct osmo_scu_pcstate_param *pcstate);
+void sccp_lbcs_local_bcast_state(struct osmo_sccp_instance *inst,
+				   const struct osmo_scu_state_param *state);
+
+/* SCCP Management (SCMG) */
+void sccp_scmg_rx_mtp_pause(struct osmo_sccp_instance *inst, uint32_t dpc);
+void sccp_scmg_rx_mtp_resume(struct osmo_sccp_instance *inst, uint32_t dpc);
diff --git a/src/sccp_lbcs.c b/src/sccp_lbcs.c
new file mode 100644
index 0000000..3aa4f7a
--- /dev/null
+++ b/src/sccp_lbcs.c
@@ -0,0 +1,68 @@
+/* SCCP Local Broadcast (LBCS) according to ITU-T Q.713/Q.714 */
+
+/* (C) 2021 by Harald Welte <laforge@gnumonks.org>
+ * All Rights reserved
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include <string.h>
+
+#include <osmocom/core/utils.h>
+#include <osmocom/core/linuxlist.h>
+#include <osmocom/core/logging.h>
+#include <osmocom/core/timer.h>
+#include <osmocom/core/fsm.h>
+
+#include <osmocom/sigtran/sccp_sap.h>
+#include <osmocom/sigtran/protocol/sua.h>
+#include <osmocom/sccp/sccp_types.h>
+
+#include "xua_internal.h"
+#include "sccp_internal.h"
+
+/* perform a "local broadcast" of a N-PCSTATE.ind */
+void sccp_lbcs_local_bcast_pcstate(struct osmo_sccp_instance *inst,
+				   const struct osmo_scu_pcstate_param *pcstate)
+{
+	struct osmo_sccp_user *scu;
+
+	llist_for_each_entry(scu, &inst->users, list) {
+		struct msgb *upmsg = sccp_msgb_alloc(__func__);
+		struct osmo_scu_prim *prim = (struct osmo_scu_prim *) msgb_put(upmsg, sizeof(*prim));
+		osmo_prim_init(&prim->oph, SCCP_SAP_USER, OSMO_SCU_PRIM_N_PCSTATE,
+				PRIM_OP_INDICATION, upmsg);
+		prim->u.pcstate = *pcstate;
+		sccp_user_prim_up(scu, prim);
+	}
+}
+
+/* perform a "local broadcast" of a N-STATE.ind */
+void sccp_lbcs_local_bcast_state(struct osmo_sccp_instance *inst,
+				 const struct osmo_scu_state_param *state)
+{
+	struct osmo_sccp_user *scu;
+
+	llist_for_each_entry(scu, &inst->users, list) {
+		struct msgb *upmsg = sccp_msgb_alloc(__func__);
+		struct osmo_scu_prim *prim = (struct osmo_scu_prim *) msgb_put(upmsg, sizeof(*prim));
+		osmo_prim_init(&prim->oph, SCCP_SAP_USER, OSMO_SCU_PRIM_N_STATE,
+				PRIM_OP_INDICATION, upmsg);
+		prim->u.state = *state;
+		sccp_user_prim_up(scu, prim);
+	}
+}
diff --git a/src/sccp_scmg.c b/src/sccp_scmg.c
new file mode 100644
index 0000000..4a8ccf6
--- /dev/null
+++ b/src/sccp_scmg.c
@@ -0,0 +1,83 @@
+/* SCCP Management (SCMG) according to ITU-T Q.713/Q.714 */
+
+/* (C) 2021 by Harald Welte <laforge@gnumonks.org>
+ * All Rights reserved
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include <string.h>
+
+#include <osmocom/core/utils.h>
+#include <osmocom/core/linuxlist.h>
+#include <osmocom/core/logging.h>
+#include <osmocom/core/timer.h>
+#include <osmocom/core/fsm.h>
+
+#include <osmocom/sigtran/sccp_sap.h>
+#include <osmocom/sigtran/protocol/sua.h>
+#include <osmocom/sccp/sccp_types.h>
+
+#include "xua_internal.h"
+#include "sccp_internal.h"
+
+/*! brief MTP -> SNM (MTP-PAUSE.ind) - inability to providing MTP service Q.714 5.2.2 */
+void sccp_scmg_rx_mtp_pause(struct osmo_sccp_instance *inst, uint32_t dpc)
+{
+	struct osmo_scu_pcstate_param pcstate;
+	/* 1) Informs the translation function to update the translation tables. */
+	/* 2) SCCP management marks as "prohibited" the status of the remote signalling point, the
+	   remote SCCP and each subsystem at the remote signalling point. */
+	/* 3) Discontinues all subsystem status tests (including SSN = 1) */
+
+	/* 4) local broadcast of "user-out-of-service" for each SSN at that dest
+	 * [this would require us to track SSNs at each PC, which we don't] */
+
+	/* 5) local broadcast of "signaling point inaccessible" */
+	/* 6) local broadcast of "remote SCCP unavailable" */
+	pcstate = (struct osmo_scu_pcstate_param) {
+		.affected_pc = dpc,
+		.restricted_importance_level = 0,
+		.sp_status = OSMO_SCCP_SP_S_INACCESSIBLE,
+		.remote_sccp_status = OSMO_SCCP_REM_SCCP_S_UNAVAILABLE_UNKNOWN,
+	};
+	sccp_lbcs_local_bcast_pcstate(inst, &pcstate);
+}
+
+/*! brief MTP -> SNM (MTP-RESUME.ind) - ability of providing the MTP service Q.714 5.2.3 */
+void sccp_scmg_rx_mtp_resume(struct osmo_sccp_instance *inst, uint32_t dpc)
+{
+	struct osmo_scu_pcstate_param pcstate;
+	/* 1) Sets the congestion state of that signalling point */
+	/* 2) Instructs the translation function to update the translation tables. */
+	/* 3) Marks as "allowed" the status of that destination, and the SCCP */
+	/* 4) - not applicable */
+	/* 5) Marks as "allowed" the status of remote subsystems */
+
+	/* 6) local broadcast of "signalling point accessible" */
+	/* 7) local broadcast of "remote SCCP accessible" */
+	pcstate = (struct osmo_scu_pcstate_param) {
+		.affected_pc = dpc,
+		.restricted_importance_level = 0,
+		.sp_status = OSMO_SCCP_SP_S_ACCESSIBLE,
+		.remote_sccp_status = OSMO_SCCP_REM_SCCP_S_AVAILABLE,
+	};
+	sccp_lbcs_local_bcast_pcstate(inst, &pcstate);
+
+	/* 8) local broadcast of "user-in-service"
+	 * [this would require us to track SSNs at each PC, which we don't] */
+}
diff --git a/src/xua_snm.c b/src/xua_snm.c
index c4dffbb..e3efc8e 100644
--- a/src/xua_snm.c
+++ b/src/xua_snm.c
@@ -31,6 +31,7 @@
 #include <osmocom/sigtran/protocol/sua.h>
 
 #include "xua_internal.h"
+#include "sccp_internal.h"
 
 /* we can share this code between M3UA and SUA as the below conditions are true */
 osmo_static_assert(M3UA_SNM_DUNA == SUA_SNM_DUNA, _sa_duna);
@@ -98,6 +99,37 @@ static void xua_tx_snm_available(struct osmo_ss7_asp *asp, const uint32_t *rctx,
 	}
 }
 
+/* generate MTP-PAUSE / MTP-RESUME towards local SCCP users */
+static void xua_snm_pc_available_to_sccp(struct osmo_sccp_instance *sccp,
+					 const uint32_t *aff_pc, unsigned int num_aff_pc,
+					 bool available)
+{
+	int i;
+	for (i = 0; i < num_aff_pc; i++) {
+		uint32_t _aff_pc = ntohl(aff_pc[i]);
+		uint32_t pc = _aff_pc & 0xffffff;
+		uint8_t mask = _aff_pc >> 24;
+
+		if (!mask) {
+			if (available)
+				sccp_scmg_rx_mtp_resume(sccp, pc);
+			else
+				sccp_scmg_rx_mtp_pause(sccp, pc);
+		} else {
+			/* we have to send one MTP primitive for each individual point
+			 * code within that mask */
+			uint32_t maskbits = (1 << mask) - 1;
+			uint32_t fullpc;
+			for (fullpc = (pc & ~maskbits); fullpc <= (pc | maskbits); fullpc++) {
+				if (available)
+					sccp_scmg_rx_mtp_resume(sccp, pc);
+				else
+					sccp_scmg_rx_mtp_pause(sccp, pc);
+			}
+		}
+	}
+}
+
 /* advertise availability of point codes (with masks) */
 void xua_snm_pc_available(struct osmo_ss7_as *as, const uint32_t *aff_pc,
 			  unsigned int num_aff_pc, const char *info_str, bool available)
@@ -107,6 +139,11 @@ void xua_snm_pc_available(struct osmo_ss7_as *as, const uint32_t *aff_pc,
 	uint32_t rctx[32];
 	unsigned int num_rctx;
 
+	/* inform local users via a MTP-{PAUSE, RESUME} primitive */
+	if (s7i->sccp)
+		xua_snm_pc_available_to_sccp(s7i->sccp, aff_pc, num_aff_pc, available);
+
+	/* inform remote ASPs via DUNA/DAVA */
 	llist_for_each_entry(asp, &s7i->asp_list, list) {
 		/* SSNM is only permitted for ASPs in ACTIVE state */
 		if (!osmo_ss7_asp_active(asp))