Bluetooth: Mesh: Adds subnet bridge states

The `brg_cfg` module implements the states needed for subnet bridge
feature. It provides two states - enable state, and bridging table
state. APIs are provided to access and modify the states. The module
handles responsibility of persistence of the states.

Signed-off-by: Omkar Kulkarni <omkar.kulkarni@nordicsemi.no>

subsys/bluetooth/Kconfig.logging

@@ -407,6 +407,10 @@ module = BT_MESH_NET
 module-str = "Network layer"
 source "subsys/logging/Kconfig.template.log_config_inherit"
 
+module = BT_MESH_BRG
+module-str = "Subnet Bridging layer"
+source "subsys/logging/Kconfig.template.log_config_inherit"
+
 module = BT_MESH_RPL
 module-str = "Replay protection list"
 source "subsys/logging/Kconfig.template.log_config_inherit"

subsys/bluetooth/mesh/CMakeLists.txt

@@ -115,7 +115,7 @@ zephyr_library_sources_ifdef(CONFIG_BT_MESH_OD_PRIV_PROXY_SRV sol_pdu_rpl_srv.c)
 
 zephyr_library_sources_ifdef(CONFIG_BT_MESH_BRG_CFG_CLI brg_cfg_cli.c)
 
-zephyr_library_sources_ifdef(CONFIG_BT_MESH_BRG_CFG_SRV brg_cfg_srv.c)
+zephyr_library_sources_ifdef(CONFIG_BT_MESH_BRG_CFG_SRV brg_cfg_srv.c brg_cfg.c)
 
 zephyr_library_sources_ifdef(CONFIG_BT_MESH_SOLICITATION solicitation.c)
 

subsys/bluetooth/mesh/Kconfig

@@ -1274,6 +1274,18 @@ config BT_MESH_BRG_CFG_SRV
 	  The Bridge Configuration Server model is used to support the configuration
 	  of the subnet bridge functionality of a node.
 
+menu "Subnet Bridge configuration"
+	visible if BT_MESH_BRG_CFG_SRV
+
+config BT_MESH_BRG_TABLE_ITEMS_MAX
+	int "Maximum number of entries in the bridging table"
+	default 16
+	range 16 255
+	help
+	  The maximum number of entries in the bridging table.
+
+endmenu
+
 config BT_MESH_BRG_CFG_CLI
 	bool "Support for Bridge Configuration Client model"
 	help

subsys/bluetooth/mesh/brg_cfg.c

@@ -0,0 +1,307 @@
+/*
+ * Copyright (c) 2024 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/* Implementation for states of Subnet Bridge feature in Bluetooth Mesh Protocol v1.1
+ * specification
+ */
+#include <errno.h>
+#include <zephyr/bluetooth/mesh.h>
+
+#include "mesh.h"
+#include "net.h"
+#include "settings.h"
+#include "brg_cfg.h"
+
+#define LOG_LEVEL CONFIG_BT_MESH_BRG_LOG_LEVEL
+#include <zephyr/logging/log.h>
+LOG_MODULE_REGISTER(bt_mesh_brg_cfg);
+
+/* Bridging table state and counter */
+static struct bt_mesh_brg_cfg_row brg_tbl[CONFIG_BT_MESH_BRG_TABLE_ITEMS_MAX];
+static uint32_t bt_mesh_brg_cfg_row_cnt;
+/* Bridging enabled state */
+static bool brg_enabled;
+
+static void brg_tbl_compact(void)
+{
+	int j = 0;
+
+	for (int k = 0; k < bt_mesh_brg_cfg_row_cnt; k++) {
+		if (brg_tbl[k].direction != 0) {
+			brg_tbl[j] = brg_tbl[k];
+			j++;
+		}
+	}
+	memset(&brg_tbl[j], 0, sizeof(brg_tbl[j]));
+	bt_mesh_brg_cfg_row_cnt--;
+}
+
+#if IS_ENABLED(CONFIG_BT_SETTINGS)
+/* Set function for initializing bridging enable state from value stored in settings. */
+static int brg_en_set(const char *name, size_t len_rd, settings_read_cb read_cb, void *cb_arg)
+{
+	int err;
+
+	if (len_rd == 0) {
+		brg_enabled = 0;
+		LOG_DBG("Cleared bridge enable state");
+		return 0;
+	}
+
+	err = bt_mesh_settings_set(read_cb, cb_arg, &brg_enabled, sizeof(brg_enabled));
+	if (err) {
+		LOG_ERR("Failed to set bridge enable state");
+		return err;
+	}
+
+	LOG_DBG("Restored bridge enable state");
+
+	return 0;
+}
+
+/* Define a setting for storing enable state */
+BT_MESH_SETTINGS_DEFINE(brg_en, "brg_en", brg_en_set);
+
+/* Set function for initializing bridging table rows from values stored in settings. */
+static int brg_tbl_set(const char *name, size_t len_rd, settings_read_cb read_cb, void *cb_arg)
+{
+	if (len_rd == 0) {
+		memset(brg_tbl, 0, sizeof(brg_tbl));
+		bt_mesh_brg_cfg_row_cnt = 0;
+		LOG_DBG("Cleared bridging table entries");
+		return 0;
+	}
+
+	int err = bt_mesh_settings_set(read_cb, cb_arg, brg_tbl, sizeof(brg_tbl));
+
+	if (err) {
+		LOG_ERR("Failed to set bridging table entries");
+		return err;
+	}
+
+	LOG_DBG("Restored bridging table");
+
+	return 0;
+}
+
+/* Define a setting for storing briging table rows */
+BT_MESH_SETTINGS_DEFINE(brg_tbl, "brg_tbl", brg_tbl_set);
+#endif
+
+bool bt_mesh_brg_cfg_enable_get(void)
+{
+	return brg_enabled;
+}
+
+int bt_mesh_brg_cfg_enable_set(bool enable)
+{
+	if (brg_enabled == enable) {
+		return 0;
+	}
+
+	brg_enabled = enable;
+#if IS_ENABLED(CONFIG_BT_SETTINGS)
+	bt_mesh_settings_store_schedule(BT_MESH_SETTINGS_BRG_PENDING);
+#endif
+	return 0;
+}
+
+void bt_mesh_brg_cfg_pending_store(void)
+{
+#if CONFIG_BT_SETTINGS
+	char *path_en = "bt/mesh/brg_en";
+	char *path_tbl = "bt/mesh/brg_tbl";
+	int err;
+
+	if (brg_enabled) {
+		err = settings_save_one(path_en, &brg_enabled, sizeof(brg_enabled));
+	} else {
+		err = settings_delete(path_en);
+	}
+
+	if (err) {
+		LOG_ERR("Failed to store %s value", path_en);
+	}
+
+
+	if (bt_mesh_brg_cfg_row_cnt) {
+		err = settings_save_one(path_tbl, &brg_tbl,
+					bt_mesh_brg_cfg_row_cnt * sizeof(brg_tbl[0]));
+	} else {
+		err = settings_delete(path_tbl);
+	}
+
+	if (err) {
+		LOG_ERR("Failed to store %s value", path_tbl);
+	}
+#endif
+}
+
+/* Remove the entry from the bridging table that corresponds with the NetKey Index of the removed
+ * subnet.
+ */
+static void brg_tbl_netkey_removed_evt(struct bt_mesh_subnet *sub, enum bt_mesh_key_evt evt)
+{
+	if (evt != BT_MESH_KEY_DELETED) {
+		return;
+	}
+
+	for (int i = 0; i < CONFIG_BT_MESH_BRG_TABLE_ITEMS_MAX; i++) {
+		if (brg_tbl[i].direction && (
+		    brg_tbl[i].net_idx1 == sub->net_idx ||
+		    brg_tbl[i].net_idx2 == sub->net_idx)) {
+			memset(&brg_tbl[i], 0, sizeof(brg_tbl[i]));
+			brg_tbl_compact();
+		}
+	}
+
+#if IS_ENABLED(CONFIG_BT_SETTINGS)
+	bt_mesh_settings_store_schedule(BT_MESH_SETTINGS_BRG_PENDING);
+#endif
+}
+
+/* Add event hook for key deletion event */
+BT_MESH_SUBNET_CB_DEFINE(sbr) = {
+	.evt_handler = brg_tbl_netkey_removed_evt,
+};
+
+int bt_mesh_brg_cfg_tbl_reset(void)
+{
+	int err = 0;
+
+	brg_enabled = false;
+	bt_mesh_brg_cfg_row_cnt = 0;
+	memset(brg_tbl, 0, sizeof(brg_tbl));
+
+#if CONFIG_BT_SETTINGS
+	err = settings_delete("bt/mesh/brg_en");
+
+	if (err) {
+		return err;
+	}
+
+	err = settings_delete("bt/mesh/brg_tbl");
+#endif
+	return err;
+}
+
+int bt_mesh_brg_cfg_tbl_get(const struct bt_mesh_brg_cfg_row **rows)
+{
+	*rows = brg_tbl;
+	return bt_mesh_brg_cfg_row_cnt;
+}
+
+int bt_mesh_brg_cfg_tbl_add(enum bt_mesh_brg_cfg_dir direction, uint16_t net_idx1,
+			    uint16_t net_idx2, uint16_t addr1, uint16_t addr2)
+{
+	/* Sanity checks */
+	if (!BT_MESH_ADDR_IS_UNICAST(addr1) || net_idx1 == net_idx2 || addr1 == addr2 ||
+	    net_idx1 > 0x03FF || net_idx2 > 0x03FF) {
+		return -EINVAL;
+	}
+
+	if (direction != BT_MESH_BRG_CFG_DIR_ONEWAY && direction != BT_MESH_BRG_CFG_DIR_TWOWAY) {
+		return -EINVAL;
+	}
+
+	if ((direction == BT_MESH_BRG_CFG_DIR_ONEWAY &&
+		(addr2 == BT_MESH_ADDR_UNASSIGNED || addr2 == BT_MESH_ADDR_ALL_NODES)) ||
+	    (direction == BT_MESH_BRG_CFG_DIR_TWOWAY &&
+		!BT_MESH_ADDR_IS_UNICAST(addr2))) {
+		return -EINVAL;
+	}
+
+	/* Check if entry already exists, if yes, then, update the direction field and it is a
+	 * success.
+	 * "If a Bridging Table state entry corresponding to the received message exists, the
+	 * element shall set the Directions field in the entry to the value of the Directions field
+	 * in the received message."
+	 */
+	for (int i = 0; i < bt_mesh_brg_cfg_row_cnt; i++) {
+		if (brg_tbl[i].net_idx1 == net_idx1 &&
+		    brg_tbl[i].net_idx2 == net_idx2 && brg_tbl[i].addr1 == addr1 &&
+		    brg_tbl[i].addr2 == addr2) {
+			brg_tbl[i].direction = direction;
+			goto store;
+		}
+	}
+
+	/* Empty element, is the current table row counter */
+	if (bt_mesh_brg_cfg_row_cnt == CONFIG_BT_MESH_BRG_TABLE_ITEMS_MAX) {
+		return -ENOMEM;
+	}
+
+	/* Update the row */
+	brg_tbl[bt_mesh_brg_cfg_row_cnt].direction = direction;
+	brg_tbl[bt_mesh_brg_cfg_row_cnt].net_idx1 = net_idx1;
+	brg_tbl[bt_mesh_brg_cfg_row_cnt].net_idx2 = net_idx2;
+	brg_tbl[bt_mesh_brg_cfg_row_cnt].addr1 = addr1;
+	brg_tbl[bt_mesh_brg_cfg_row_cnt].addr2 = addr2;
+	bt_mesh_brg_cfg_row_cnt++;
+
+store:
+#if IS_ENABLED(CONFIG_BT_SETTINGS)
+	bt_mesh_settings_store_schedule(BT_MESH_SETTINGS_BRG_PENDING);
+#endif
+
+	return 0;
+}
+
+void bt_mesh_brg_cfg_tbl_foreach_subnet(uint16_t src, uint16_t dst, uint16_t net_idx,
+					bt_mesh_brg_cfg_cb_t cb, void *user_data)
+{
+	for (int i = 0; i < bt_mesh_brg_cfg_row_cnt; i++) {
+		if ((brg_tbl[i].direction ==  BT_MESH_BRG_CFG_DIR_ONEWAY ||
+		     brg_tbl[i].direction == BT_MESH_BRG_CFG_DIR_TWOWAY) &&
+		     brg_tbl[i].net_idx1 == net_idx && brg_tbl[i].addr1 == src &&
+		     brg_tbl[i].addr2 == dst) {
+			cb(brg_tbl[i].net_idx2, user_data);
+		} else if ((brg_tbl[i].direction == BT_MESH_BRG_CFG_DIR_TWOWAY &&
+		     brg_tbl[i].net_idx2 == net_idx && brg_tbl[i].addr2 == src &&
+		     brg_tbl[i].addr1 == dst)) {
+			cb(brg_tbl[i].net_idx1, user_data);
+		}
+	}
+}
+
+void bt_mesh_brg_cfg_tbl_remove(uint16_t net_idx1, uint16_t net_idx2, uint16_t addr1,
+				uint16_t addr2)
+{
+#if IS_ENABLED(CONFIG_BT_SETTINGS)
+	bool store = false;
+#endif
+
+	/* Iterate over items and set matching row to 0, if nothing exist, or nothing matches, then
+	 * it is success (similar to add)
+	 */
+	if (bt_mesh_brg_cfg_row_cnt == 0) {
+		return;
+	}
+
+	for (int i = 0; i < bt_mesh_brg_cfg_row_cnt; i++) {
+		/* Match according to remove behavior in Section 4.4.9.2.2 of MshPRT_v1.1 */
+		if (brg_tbl[i].direction) {
+			if (!(brg_tbl[i].net_idx1 == net_idx1 && brg_tbl[i].net_idx2 == net_idx2)) {
+				continue;
+			}
+
+			if ((brg_tbl[i].addr1 == addr1 && brg_tbl[i].addr2 == addr2) ||
+			    (addr2 == BT_MESH_ADDR_UNASSIGNED && brg_tbl[i].addr1 == addr1) ||
+			    (addr1 == BT_MESH_ADDR_UNASSIGNED && brg_tbl[i].addr2 == addr2)) {
+				memset(&brg_tbl[i], 0, sizeof(brg_tbl[i]));
+				brg_tbl_compact();
+#if IS_ENABLED(CONFIG_BT_SETTINGS)
+				store = true;
+#endif
+			}
+		}
+	}
+#if IS_ENABLED(CONFIG_BT_SETTINGS)
+	if (store) {
+		bt_mesh_settings_store_schedule(BT_MESH_SETTINGS_BRG_PENDING);
+	}
+#endif
+}