layer23: Introduce apn_fsm

This allows further control on the state of the APNs, as well as
a step further towards administering them through VTY.

Change-Id: I2cc732dfb020d31ab89025e7e22276b819dcb24a

11 files changed, 334 insertions, 15 deletions

diff --git a/src/host/layer23/include/osmocom/bb/common/Makefile.am b/src/host/layer23/include/osmocom/bb/common/Makefile.am
index 28caf78d..7c0fa972 100644
--- a/src/host/layer23/include/osmocom/bb/common/Makefile.am
+++ b/src/host/layer23/include/osmocom/bb/common/Makefile.am
@@ -1,5 +1,6 @@
 noinst_HEADERS = \
 	apn.h \
+	apn_fsm.h \
 	l1ctl.h \
 	l1l2_interface.h \
 	l23_app.h \
diff --git a/src/host/layer23/include/osmocom/bb/common/apn.h b/src/host/layer23/include/osmocom/bb/common/apn.h
index 94784ef7..538b31dd 100644
--- a/src/host/layer23/include/osmocom/bb/common/apn.h
+++ b/src/host/layer23/include/osmocom/bb/common/apn.h
@@ -20,6 +20,7 @@
 #include <osmocom/core/linuxlist.h>
 #include <osmocom/core/select.h>
 #include <osmocom/core/tun.h>
+#include <osmocom/bb/common/apn_fsm.h>
 
 struct osmocom_ms;
 
@@ -50,6 +51,7 @@ struct osmobb_apn {
 		bool tx_gpdu_seq;
 	} cfg;
 	struct osmo_tundev *tun;
+	struct apn_fsm_ctx fsm;
 };
 
 struct osmobb_apn *apn_alloc(struct osmocom_ms *ms, const char *name);
diff --git a/src/host/layer23/include/osmocom/bb/common/apn_fsm.h b/src/host/layer23/include/osmocom/bb/common/apn_fsm.h
new file mode 100644
index 00000000..890267c9
--- /dev/null
+++ b/src/host/layer23/include/osmocom/bb/common/apn_fsm.h
@@ -0,0 +1,29 @@
+#pragma once
+
+#include <osmocom/core/fsm.h>
+
+struct osmobb_apn;
+
+enum apn_fsm_states {
+	APN_ST_DISABLED,
+	APN_ST_INACTIVE,
+	APN_ST_ACTIVATING,
+	APN_ST_ACTIVE,
+};
+
+enum apn_fsm_events {
+	APN_EV_GPRS_ALLOWED,	/* data: bool *allowed */
+	APN_EV_GMM_ATTACHED,
+	APN_EV_GMM_DETACHED,
+	APN_EV_RX_SM_ACT_PDP_CTX_REJ, /* data: enum gsm48_gsm_cause *cause */
+	APN_EV_RX_SM_ACT_PDP_CTX_ACC,
+	APN_EV_RX_SM_DEACT_PDP_CTX_ACC,
+};
+
+struct apn_fsm_ctx {
+	struct osmo_fsm_inst *fi;
+	struct osmobb_apn *apn;
+};
+
+int apn_fsm_ctx_init(struct apn_fsm_ctx *ctx, struct osmobb_apn *apn);
+void apn_fsm_ctx_release(struct apn_fsm_ctx *ctx);
diff --git a/src/host/layer23/include/osmocom/bb/common/settings.h b/src/host/layer23/include/osmocom/bb/common/settings.h
index 88ce280a..38faa4bb 100644
--- a/src/host/layer23/include/osmocom/bb/common/settings.h
+++ b/src/host/layer23/include/osmocom/bb/common/settings.h
@@ -205,6 +205,7 @@ struct gprs_settings {
 int gprs_settings_init(struct osmocom_ms *ms);
 int gprs_settings_fi(struct osmocom_ms *ms);
 struct osmobb_apn *ms_find_apn_by_name(struct osmocom_ms *ms, const char *apn_name);
+int ms_dispatch_all_apn(struct osmocom_ms *ms, uint32_t event, void *data);
 
 extern char *layer2_socket_path;
 
diff --git a/src/host/layer23/src/common/Makefile.am b/src/host/layer23/src/common/Makefile.am
index 60af3b83..8f5aebaa 100644
--- a/src/host/layer23/src/common/Makefile.am
+++ b/src/host/layer23/src/common/Makefile.am
@@ -16,6 +16,7 @@ AM_CFLAGS = \
 noinst_LIBRARIES = liblayer23.a
 liblayer23_a_SOURCES = \
 	apn.c \
+	apn_fsm.c \
 	gps.c \
 	l1ctl.c \
 	l1l2_interface.c \
diff --git a/src/host/layer23/src/common/apn.c b/src/host/layer23/src/common/apn.c
index 636246a9..b9b032c9 100644
--- a/src/host/layer23/src/common/apn.c
+++ b/src/host/layer23/src/common/apn.c
@@ -35,25 +35,33 @@ struct osmobb_apn *apn_alloc(struct osmocom_ms *ms, const char *name)
 	if (!apn)
 		return NULL;
 
+	if (apn_fsm_ctx_init(&apn->fsm, apn) != 0)
+		goto ret_free;
+
 	talloc_set_name(apn, "apn_%s", name);
 	apn->cfg.name = talloc_strdup(apn, name);
 	apn->cfg.shutdown = true;
 	apn->cfg.tx_gpdu_seq = true;
 
 	apn->tun = osmo_tundev_alloc(apn, name);
-	if (!apn->tun) {
-		talloc_free(apn);
-		return NULL;
-	}
+	if (!apn->tun)
+		goto ret_free_fsm;
 	osmo_tundev_set_priv_data(apn->tun, apn);
 
 	apn->ms = ms;
 	llist_add_tail(&apn->list, &ms->gprs.apn_list);
 	return apn;
+
+ret_free_fsm:
+	apn_fsm_ctx_release(&apn->fsm);
+ret_free:
+	talloc_free(apn);
+	return NULL;
 }
 
 void apn_free(struct osmobb_apn *apn)
 {
+	apn_fsm_ctx_release(&apn->fsm);
 	llist_del(&apn->list);
 	osmo_tundev_free(apn->tun);
 	talloc_free(apn);
diff --git a/src/host/layer23/src/common/apn_fsm.c b/src/host/layer23/src/common/apn_fsm.c
new file mode 100644
index 00000000..edaac48a
--- /dev/null
+++ b/src/host/layer23/src/common/apn_fsm.c
@@ -0,0 +1,245 @@
+/* Lifecycle of an APN */
+/*
+ * (C) 2023 by sysmocom - s.m.f.c. GmbH <info@sysmocom.de>
+ * All Rights Reserved
+ *
+ * SPDX-License-Identifier: AGPL-3.0+
+ *
+ * Author: Pau Espin Pedrol <pespin@sysmocom.de>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation; either version 3 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 Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <errno.h>
+#include <osmocom/core/tdef.h>
+#include <osmocom/core/utils.h>
+
+#include <osmocom/bb/common/logging.h>
+#include <osmocom/bb/common/apn_fsm.h>
+#include <osmocom/bb/common/apn.h>
+#define X(s) (1 << (s))
+
+static struct osmo_tdef T_defs_apn[] = {
+	{ .T=1, .default_val=30, .desc = "Activating timeout (s)" },
+	{ 0 } /* empty item at the end */
+};
+
+static const struct osmo_tdef_state_timeout apn_fsm_timeouts[32] = {
+	[APN_ST_DISABLED] = {},
+	[APN_ST_INACTIVE] = {},
+	[APN_ST_ACTIVATING] = { .T=1 },
+	[APN_ST_ACTIVE] = {},
+};
+
+#define apn_fsm_state_chg(fi, NEXT_STATE) \
+	osmo_tdef_fsm_inst_state_chg(fi, NEXT_STATE, apn_fsm_timeouts, T_defs_apn, -1)
+
+static void st_apn_disabled_on_enter(struct osmo_fsm_inst *fi, uint32_t prev_state)
+{
+	struct apn_fsm_ctx *ctx = (struct apn_fsm_ctx *)fi->priv;
+
+	apn_stop(ctx->apn);
+}
+
+static void st_apn_disabled(struct osmo_fsm_inst *fi, uint32_t event, void *data)
+{
+	switch (event) {
+	case APN_EV_GPRS_ALLOWED:
+		if (*((bool *)data) == true)
+			apn_fsm_state_chg(fi, APN_ST_INACTIVE);
+		break;
+	default:
+		OSMO_ASSERT(0);
+	}
+}
+
+static void st_apn_inactive_on_enter(struct osmo_fsm_inst *fi, uint32_t prev_state)
+{
+	struct apn_fsm_ctx *ctx = (struct apn_fsm_ctx *)fi->priv;
+
+	int rc = apn_start(ctx->apn);
+	if (rc < 0)
+		apn_fsm_state_chg(fi, APN_ST_DISABLED);
+
+	/* FIXME: Here once we find a way to store whether the ms object is GMM
+	attached, we can transition directly to ACTIVATING. */
+}
+
+static void st_apn_inactive(struct osmo_fsm_inst *fi, uint32_t event, void *data)
+{
+	switch (event) {
+	case APN_EV_GPRS_ALLOWED:
+		if (*((bool *)data) == false)
+			apn_fsm_state_chg(fi, APN_ST_DISABLED);
+		break;
+	case APN_EV_GMM_ATTACHED:
+		apn_fsm_state_chg(fi, APN_ST_ACTIVATING);
+		break;
+	default:
+		OSMO_ASSERT(0);
+	}
+}
+
+static void st_apn_activating_on_enter(struct osmo_fsm_inst *fi, uint32_t prev_state)
+{
+	/* FIXME: We could send SMREG-PDP_ACT.req from here. Right now that's done by the app. */
+}
+
+static void st_apn_activating(struct osmo_fsm_inst *fi, uint32_t event, void *data)
+{
+	switch (event) {
+	case APN_EV_GPRS_ALLOWED:
+		/* TODO: Tx PDP DEACT ACC */
+		apn_fsm_state_chg(fi, APN_ST_DISABLED);
+		break;
+	case APN_EV_GMM_DETACHED:
+		apn_fsm_state_chg(fi, APN_ST_INACTIVE);
+		break;
+	case APN_EV_RX_SM_ACT_PDP_CTX_REJ:
+		apn_fsm_state_chg(fi, APN_ST_INACTIVE);
+		break;
+	case APN_EV_RX_SM_ACT_PDP_CTX_ACC:
+		apn_fsm_state_chg(fi, APN_ST_ACTIVE);
+		break;
+	default:
+		OSMO_ASSERT(0);
+	}
+}
+
+static void st_apn_active_on_enter(struct osmo_fsm_inst *fi, uint32_t prev_state)
+{
+	struct apn_fsm_ctx *ctx = (struct apn_fsm_ctx *)fi->priv;
+	struct osmo_netdev *netdev;
+
+	netdev = osmo_tundev_get_netdev(ctx->apn->tun);
+	osmo_netdev_ifupdown(netdev, true);
+}
+
+static void st_apn_active(struct osmo_fsm_inst *fi, uint32_t event, void *data)
+{
+	switch (event) {
+	case APN_EV_GPRS_ALLOWED:
+		/* TODO: Tx PDP DEACT ACC */
+		apn_fsm_state_chg(fi, APN_ST_DISABLED);
+		break;
+	case APN_EV_GMM_DETACHED:
+		apn_fsm_state_chg(fi, APN_ST_INACTIVE);
+		break;
+	case APN_EV_RX_SM_DEACT_PDP_CTX_ACC:
+		apn_fsm_state_chg(fi, APN_ST_INACTIVE);
+		break;
+	default:
+		OSMO_ASSERT(0);
+	}
+}
+
+static int apn_fsm_timer_cb(struct osmo_fsm_inst *fi)
+{
+	switch (fi->T) {
+	case 1:
+		apn_fsm_state_chg(fi, APN_ST_INACTIVE);
+		break;
+	default:
+		OSMO_ASSERT(0);
+	}
+	return 0;
+}
+
+static struct osmo_fsm_state apn_fsm_states[] = {
+	[APN_ST_DISABLED] = {
+		.in_event_mask =
+			X(APN_EV_GPRS_ALLOWED),
+		.out_state_mask =
+			X(APN_ST_INACTIVE),
+		.name = "DISABLED",
+		.onenter = st_apn_disabled_on_enter,
+		.action = st_apn_disabled,
+	},
+	[APN_ST_INACTIVE] = {
+		.in_event_mask =
+			X(APN_EV_GPRS_ALLOWED) |
+			X(APN_EV_GMM_ATTACHED),
+		.out_state_mask =
+			X(APN_ST_ACTIVATING),
+		.name = "INACTIVE",
+		.onenter = st_apn_inactive_on_enter,
+		.action = st_apn_inactive,
+	},
+	[APN_ST_ACTIVATING] = {
+		.in_event_mask =
+			X(APN_EV_GPRS_ALLOWED) |
+			X(APN_EV_GMM_DETACHED) |
+			X(APN_EV_RX_SM_ACT_PDP_CTX_REJ) |
+			X(APN_EV_RX_SM_ACT_PDP_CTX_ACC),
+		.out_state_mask =
+			X(APN_ST_DISABLED) |
+			X(APN_ST_INACTIVE) |
+			X(APN_ST_ACTIVE),
+		.name = "ACTIVATING",
+		.onenter = st_apn_activating_on_enter,
+		.action = st_apn_activating,
+	},
+	[APN_ST_ACTIVE] = {
+		.in_event_mask =
+			X(APN_EV_GPRS_ALLOWED) |
+			X(APN_EV_GMM_DETACHED)|
+			X(APN_EV_RX_SM_DEACT_PDP_CTX_ACC),
+		.out_state_mask =
+			X(APN_ST_DISABLED) |
+			X(APN_ST_INACTIVE),
+		.name = "ACTIVE",
+		.onenter = st_apn_active_on_enter,
+		.action = st_apn_active,
+	},
+};
+
+const struct value_string apn_fsm_event_names[] = {
+	{ APN_EV_GPRS_ALLOWED,		"GPRS_ALLOWED" },
+	{ APN_EV_GMM_ATTACHED,		"GMM_ATTACHED" },
+	{ APN_EV_GMM_DETACHED,		"GMM_DETACHED" },
+	{ APN_EV_RX_SM_ACT_PDP_CTX_REJ,	"ACT_PDP_CTX_REJ" },
+	{ APN_EV_RX_SM_ACT_PDP_CTX_ACC,	"ACT_PDP_CTX_ACC" },
+	{ APN_EV_RX_SM_DEACT_PDP_CTX_ACC, "DEACT_PDP_CTX_ACC" },
+	{ 0, NULL }
+};
+
+struct osmo_fsm apn_fsm = {
+	.name = "APN",
+	.states = apn_fsm_states,
+	.num_states = ARRAY_SIZE(apn_fsm_states),
+	.timer_cb = apn_fsm_timer_cb,
+	.event_names = apn_fsm_event_names,
+	.log_subsys = DTUN,
+	.timer_cb = apn_fsm_timer_cb,
+};
+
+int apn_fsm_ctx_init(struct apn_fsm_ctx *ctx, struct osmobb_apn *apn)
+{
+	ctx->apn = apn;
+	ctx->fi = osmo_fsm_inst_alloc(&apn_fsm, apn, ctx, LOGL_INFO, NULL);
+	if (!ctx->fi)
+		return -ENODATA;
+
+	return 0;
+}
+
+void apn_fsm_ctx_release(struct apn_fsm_ctx *ctx)
+{
+	osmo_fsm_inst_free(ctx->fi);
+}
+
+static __attribute__((constructor)) void apn_fsm_init(void)
+{
+	OSMO_ASSERT(osmo_fsm_register(&apn_fsm) == 0);
+	osmo_tdefs_reset(T_defs_apn);
+}
diff --git a/src/host/layer23/src/common/settings.c b/src/host/layer23/src/common/settings.c
index 565da961..986d551b 100644
--- a/src/host/layer23/src/common/settings.c
+++ b/src/host/layer23/src/common/settings.c
@@ -252,3 +252,14 @@ struct osmobb_apn *ms_find_apn_by_name(struct osmocom_ms *ms, const char *apn_na
 	}
 	return NULL;
 }
+
+int ms_dispatch_all_apn(struct osmocom_ms *ms, uint32_t event, void *data)
+{
+	struct gprs_settings *set = &ms->gprs;
+	int rc = 0;
+	struct osmobb_apn *apn;
+
+	llist_for_each_entry(apn, &set->apn_list, list)
+		rc |= osmo_fsm_inst_dispatch(apn->fsm.fi, event, data);
+	return rc;
+}
diff --git a/src/host/layer23/src/modem/gmm.c b/src/host/layer23/src/modem/gmm.c
index f3a936aa..b95f15a2 100644
--- a/src/host/layer23/src/modem/gmm.c
+++ b/src/host/layer23/src/modem/gmm.c
@@ -64,10 +64,12 @@ static int modem_gmm_prim_up_cb(struct osmo_gprs_gmm_prim *gmm_prim, void *user_
 				ms->subscr.ptmsi = gmm_prim->gmmreg.attach_cnf.acc.allocated_ptmsi;
 				app_data.modem_state = MODEM_ST_ATTACHED;
 				/* Activate APN if not yet already: */
-				apn = llist_first_entry_or_null(&ms->gprs.apn_list, struct osmobb_apn, list);
-				if (!apn || apn->cfg.shutdown)
-					break;
-				modem_sm_smreg_pdp_act_req(ms, apn);
+				llist_for_each_entry(apn, &ms->gprs.apn_list, list) {
+					if (apn->fsm.fi->state != APN_ST_INACTIVE)
+						continue;
+					osmo_fsm_inst_dispatch(apn->fsm.fi, APN_EV_GMM_ATTACHED, NULL);
+					modem_sm_smreg_pdp_act_req(ms, apn);
+				}
 			} else {
 				uint8_t cause = gmm_prim->gmmreg.attach_cnf.rej.cause;
 				LOGP(DGMM, LOGL_ERROR, "%s(): Rx %s: Attach rejected, cause=%u (%s)\n",
@@ -94,6 +96,9 @@ static int modem_gmm_prim_up_cb(struct osmo_gprs_gmm_prim *gmm_prim, void *user_
 			break;
 		case OSMO_PRIM(OSMO_GPRS_GMM_GMMREG_DETACH, PRIM_OP_CONFIRM):
 		case OSMO_PRIM(OSMO_GPRS_GMM_GMMREG_DETACH, PRIM_OP_INDICATION):
+				LOGP(DGMM, LOGL_NOTICE, "%s(): Rx %s\n", __func__, pdu_name);
+				ms_dispatch_all_apn(ms, APN_EV_GMM_DETACHED, NULL);
+			break;
 		default:
 			LOGP(DGMM, LOGL_ERROR, "%s(): Rx %s UNIMPLEMENTED\n", __func__, pdu_name);
 			break;
diff --git a/src/host/layer23/src/modem/sm.c b/src/host/layer23/src/modem/sm.c
index 56b223f5..aac2b52a 100644
--- a/src/host/layer23/src/modem/sm.c
+++ b/src/host/layer23/src/modem/sm.c
@@ -50,24 +50,28 @@
 static int modem_sm_handle_pdp_act_cnf(struct osmocom_ms *ms, struct osmo_gprs_sm_prim *sm_prim)
 {
 	const char *pdu_name = osmo_gprs_sm_prim_name(sm_prim);
-	struct osmobb_apn *apn = llist_first_entry_or_null(&ms->gprs.apn_list, struct osmobb_apn, list);
+	struct osmobb_apn *apn = NULL, *apn_it;
 	struct osmo_netdev *netdev;
 	char buf_addr[INET6_ADDRSTRLEN];
 	char buf_addr2[INET6_ADDRSTRLEN];
 	int rc;
 
+	llist_for_each_entry(apn_it, &ms->gprs.apn_list, list) {
+		if (apn_it->fsm.fi->state == APN_ST_ACTIVATING) {
+			apn = apn_it;
+			break;
+		}
+	}
+
 	if (!apn) {
 		LOGP(DSM, LOGL_ERROR, "Rx %s but have no APN!\n", pdu_name);
 		return -ENOENT;
 	}
-	if (apn->cfg.shutdown) {
-		LOGPAPN(LOGL_ERROR, apn, "Rx %s but APN is administratively shutdown!\n", pdu_name);
-		return -ENOENT;
-	}
 
 	if (!sm_prim->smreg.pdp_act_cnf.accepted) {
 		LOGPAPN(LOGL_ERROR, apn, "Rx %s: Activate PDP failed! cause '%s'\n", pdu_name,
 			get_value_string(gsm48_gsm_cause_names, sm_prim->smreg.pdp_act_cnf.rej.cause));
+		osmo_fsm_inst_dispatch(apn->fsm.fi, APN_EV_RX_SM_ACT_PDP_CTX_REJ, NULL);
 		/* TODO: maybe retry ? */
 		return 0;
 	}
@@ -117,6 +121,8 @@ static int modem_sm_handle_pdp_act_cnf(struct osmocom_ms *ms, struct osmo_gprs_s
 
 	/* TODO: Handle PCO */
 	/* TODO: Handle QoS */
+
+	osmo_fsm_inst_dispatch(apn->fsm.fi, APN_EV_RX_SM_ACT_PDP_CTX_ACC, NULL);
 	return rc;
 }
 
diff --git a/src/host/layer23/src/modem/vty.c b/src/host/layer23/src/modem/vty.c
index 33891d46..77f0885f 100644
--- a/src/host/layer23/src/modem/vty.c
+++ b/src/host/layer23/src/modem/vty.c
@@ -257,6 +257,7 @@ DEFUN(cfg_ms_no_apn, cfg_ms_no_apn_cmd, "no apn APN_NAME",
 {
 	struct osmocom_ms *ms = vty->index;
 	struct osmobb_apn *apn;
+	bool on = false;
 
 	apn = ms_find_apn_by_name(ms, argv[0]);
 	if (!apn) {
@@ -264,6 +265,9 @@ DEFUN(cfg_ms_no_apn, cfg_ms_no_apn_cmd, "no apn APN_NAME",
 		return CMD_WARNING;
 	}
 
+	/* Disable APN before getting rid of it. */
+	osmo_fsm_inst_dispatch(apn->fsm.fi, APN_EV_GPRS_ALLOWED, &on);
+
 	apn_free(apn);
 
 	return CMD_SUCCESS;
@@ -326,9 +330,12 @@ DEFUN(cfg_apn_shutdown, cfg_apn_shutdown_cmd,
 	"Put the APN in administrative shut-down\n")
 {
 	struct osmobb_apn *apn = (struct osmobb_apn *) vty->index;
+	bool on = false;
+	int rc;
 
 	if (!apn->cfg.shutdown) {
-		if (apn_stop(apn)) {
+		rc = osmo_fsm_inst_dispatch(apn->fsm.fi, APN_EV_GPRS_ALLOWED, &on);
+		if (rc < 0) {
 			vty_out(vty, "%% Failed to Stop APN%s", VTY_NEWLINE);
 			return CMD_WARNING;
 		}
@@ -343,13 +350,16 @@ DEFUN(cfg_apn_no_shutdown, cfg_apn_no_shutdown_cmd,
 	NO_STR "Remove the APN from administrative shut-down\n")
 {
 	struct osmobb_apn *apn = (struct osmobb_apn *) vty->index;
+	bool on = true;
+	int rc;
 
 	if (apn->cfg.shutdown) {
 		if (!apn->cfg.dev_name) {
 			vty_out(vty, "%% Failed to start APN, tun-device is not configured%s", VTY_NEWLINE);
 			return CMD_WARNING;
 		}
-		if (apn_start(apn) < 0) {
+		rc = osmo_fsm_inst_dispatch(apn->fsm.fi, APN_EV_GPRS_ALLOWED, &on);
+		if (rc < 0) {
 			vty_out(vty, "%% Failed to start APN, check log for details%s", VTY_NEWLINE);
 			return CMD_WARNING;
 		}