Bluetooth: Mesh: Adds subnet bridge states

`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 the states.

Signed-off-by: Omkar Kulkarni <[email protected]>

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

@@ -1234,6 +1234,18 @@ 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 +1,317 @@
+/*
+ * Copyright (c) 2024 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/* Implimentation for Bridging Table state of Subnet Bridge feature
+ * in Bluetooth Mesh Protocol v1.1 specification
+ */
+
+#include <zephyr/kernel.h>
+#include <string.h>
+#include <errno.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <zephyr/sys/atomic.h>
+#include <zephyr/sys/util.h>
+#include <zephyr/sys/byteorder.h>
+
+#include <zephyr/net/buf.h>
+#include <zephyr/bluetooth/bluetooth.h>
+#include <zephyr/bluetooth/conn.h>
+#include <zephyr/bluetooth/mesh.h>
+
+#include "mesh.h"
+#include "net.h"
+#include "subnet.h"
+#include "settings.h"
+#include "brg_cfg.h"
+
+#define LOG_LEVEL CONFIG_BT_MESH_NET_LOG_LEVEL
+#include <zephyr/logging/log.h>
+LOG_MODULE_REGISTER(bt_mesh_brg_cfg);
+
+/* Bridging table state. Each item is a slist node. */
+static struct brg_tbl_row brg_tbl[CONFIG_BT_MESH_BRG_TABLE_ITEMS_MAX];
+static uint32_t brg_tbl_row_cnt;
+static bool brg_enabled;
+
+static void brg_tbl_compact(void)
+{
+	int j = 0;
+
+	for (int k = 0; k < brg_tbl_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]));
+	brg_tbl_row_cnt--;
+}
+
+#if IS_ENABLED(CONFIG_BT_SETTINGS)
+static int brgen_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 sbren");
+
+	return 0;
+}
+
+/* Define a setting for storing enable state */
+BT_MESH_SETTINGS_DEFINE(brgen, "brgen", brgen_set);
+
+/* Set function for initializing bridging table rows from brg_tbl slist */
+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));
+		brg_tbl_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 brg_tbl");
+
+	return 0;
+}
+
+/* Define a setting for storing briging table rows */
+BT_MESH_SETTINGS_DEFINE(brgbt, "brgbt", brg_tbl_set);
+#endif
+
+bool brg_cfg_enable_get(void)
+{
+	return brg_enabled;
+}
+
+int 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_en_pending_store(void)
+{
+#if CONFIG_BT_SETTINGS
+	char *path = "bt/mesh/brgen";
+	int err;
+
+	if (brg_enabled) {
+		err = settings_save_one(path, &brg_enabled, sizeof(brg_enabled));
+	} else {
+		err = settings_delete(path);
+	}
+
+	if (err) {
+		LOG_ERR("Failed to store %s value", path);
+	}
+#endif
+}
+
+void bt_mesh_brg_tbl_pending_store(void)
+{
+#if CONFIG_BT_SETTINGS
+	char *path = "bt/mesh/brgbt";
+	char path_bt[20];
+	int err;
+
+	if (!brg_tbl_row_cnt) {
+		err = settings_save_one(path, &brg_tbl, brg_tbl_row_cnt * sizeof(brg_tbl[0]));
+	} else {
+		err = settings_delete(path);
+	}
+
+	if (err) {
+		LOG_ERR("Failed to store %s value", path_bt);
+	}
+#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)
+{
+	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 brg_cfg_init(void)
+{
+	memset(brg_tbl, 0, sizeof(brg_tbl));
+	brg_tbl_row_cnt = 0;
+	return 0;
+}
+
+int brg_cfg_tbl_reset(void)
+{
+	brg_cfg_init();
+
+	int err = settings_delete("bt/mesh/brgen");
+
+	if (err) {
+		return err;
+	}
+	err = settings_delete("bt/mesh/brgbt");
+
+	return err;
+}
+
+int brg_cfg_tbl_get(const struct brg_tbl_row **rows)
+{
+	*rows = brg_tbl;
+	return brg_tbl_row_cnt;
+}
+
+int brg_cfg_tbl_add(enum brg_tbl_direction direction, uint16_t net_idx1, uint16_t net_idx2,
+			uint16_t addr1, uint16_t addr2)
+{
+	/* Sanity check */
+	if (!BT_MESH_ADDR_IS_UNICAST(addr1) || net_idx1 == net_idx2 || addr1 == addr2 ||
+	    net_idx1 > 0x03FF || net_idx2 > 0x03FF ||
+	    (direction != BRG_ADDR1_TO_ADDR2 && direction != BRG_ADDR1_TF_ADDR2) ||
+	    (direction == BRG_ADDR1_TO_ADDR2 &&
+		(addr2 == BT_MESH_ADDR_UNASSIGNED || addr2 == BT_MESH_ADDR_ALL_NODES)) ||
+	    (direction == BRG_ADDR1_TF_ADDR2 && !BT_MESH_ADDR_IS_UNICAST(addr2)))	{
+		return -EINVAL;
+	}
+
+	/* Check if entry already exists, if yes, then it is success. */
+	for (int i = 0; i < brg_tbl_row_cnt; i++) {
+		if (brg_tbl[i].direction == direction && brg_tbl[i].net_idx1 == net_idx1 &&
+		    brg_tbl[i].net_idx2 == net_idx2 && brg_tbl[i].addr1 == addr1 &&
+		    brg_tbl[i].addr2 == addr2) {
+			return 0;
+		}
+	}
+
+	/* Empty element, is the current table row counter */
+	if (brg_tbl_row_cnt == CONFIG_BT_MESH_BRG_TABLE_ITEMS_MAX) {
+		return -ENOMEM;
+	}
+
+	/* Update the row */
+	brg_tbl[brg_tbl_row_cnt].direction = direction;
+	brg_tbl[brg_tbl_row_cnt].net_idx1 = net_idx1;
+	brg_tbl[brg_tbl_row_cnt].net_idx2 = net_idx2;
+	brg_tbl[brg_tbl_row_cnt].addr1 = addr1;
+	brg_tbl[brg_tbl_row_cnt].addr2 = addr2;
+	brg_tbl_row_cnt++;
+
+#if IS_ENABLED(CONFIG_BT_SETTINGS)
+	bt_mesh_settings_store_schedule(BT_MESH_SETTINGS_BRG_PENDING);
+#endif
+
+	return 0;
+}
+
+static int itr;
+
+int brg_cfg_tbl_check_start(void)
+{
+	itr = 0;
+
+	if (!brg_tbl_row_cnt) {
+		return -ENOENT;
+	}
+
+	return 0;
+}
+
+int brg_cfg_tbl_check_itr(uint16_t src, uint16_t dst, uint16_t netidx, uint16_t *new_netidx)
+{
+	/* Iterate over items */
+	*new_netidx = BRG_NETIDX_NOMATCH;
+	if (itr >= brg_tbl_row_cnt) {
+		return -ENOENT;
+	}
+
+	if ((brg_tbl[itr].direction ==  1 || brg_tbl[itr].direction == 2) &&
+		brg_tbl[itr].net_idx1 == netidx && brg_tbl[itr].addr1 == src &&
+		brg_tbl[itr].addr2 == dst) {
+		*new_netidx = brg_tbl[itr].net_idx2;
+		goto exititr;
+	}
+
+	if (brg_tbl[itr].direction == 2 &&
+		brg_tbl[itr].net_idx2 == netidx && brg_tbl[itr].addr2 == src &&
+		brg_tbl[itr].addr1 == dst) {
+		*new_netidx = brg_tbl[itr].net_idx1;
+		goto exititr;
+	}
+
+exititr:
+	itr++;
+	return 0;
+}
+
+int brg_cfg_tbl_remove(uint16_t net_idx1, uint16_t net_idx2, uint16_t addr1, uint16_t addr2)
+{
+	/* Iterate over items and set matching row to 0, if nothing exist, or
+	 * nopthing matches, then it is success.
+	 */
+	if (brg_tbl_row_cnt == 0) {
+		return 0;
+	}
+
+	for (int i = 0; i < brg_tbl_row_cnt; i++) {
+		if (brg_tbl[i].direction && brg_tbl[i].net_idx1 == net_idx1 &&
+		    brg_tbl[i].net_idx2 == net_idx2 && brg_tbl[i].addr1 == addr1 &&
+		    brg_tbl[i].addr2 == addr2) {
+			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
+
+			return 0;
+		}
+	}
+
+	return 0;
+}