Bluetooth: Mesh: Populate Bridge Config Server

Adds implementation for the Bridge Configuration Server model.

Updates `brg_cfg` module to add sanity check for
bt_mesh_brg_cfg_tbl_remove() API. Also, updates the unit test
accordingly.

Adds documentation for the Bridge Configuration Server model

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

doc/connectivity/bluetooth/api/mesh/brg_cfg_srv.rst

@@ -3,6 +3,35 @@
 Bridge Configuration Server
 ###########################
 
+The Bridge Configuration Server model is a foundation model defined by the Bluetooth Mesh
+specification. It is an optional model, enabled with the
+:kconfig:option:`CONFIG_BT_MESH_BRG_CFG_SRV` configuration option. This model extends
+the :ref:`bluetooth_mesh_models_cfg_srv` model.
+
+The Bridge Configuration Server model was introduced in the Bluetooth Mesh Protocol Specification
+version 1.1, and is used for supporting and configuring the Subnet Bridge feature.
+
+The Bridge Configuration Server model relies on a :ref:`bluetooth_mesh_models_brg_cfg_cli` to
+configure it. The Bridge Configuration Server model only accepts messages encrypted with the node’s
+device key.
+
+If present, the Bridge Configuration Server model must be instantiated on the primary element.
+
+The Bridge Configuration Server model provides access to the following three states:
+
+* **Subnet Bridge state**: This state enables or disables the Subnet Bridge feature on a node. When
+  the Subnet Bridge feature is enabled on a node, the node can transfer received messages from one
+  subnet to another as specified by the Bridging Table state.
+
+* **Bridging Table state**: This state holds the bridging table. This table is used to check if
+  incoming messages can be bridged from one subnet to another. The maximum number of rows supported
+  by the Bridging Table state can be configured using the
+  :kconfig:option:`CONFIG_BT_MESH_BRG_TABLE_ITEMS_MAX` configuration option.
+
+* **Bridging Table Size state**: This state reports the maximum number of rows supported by the
+  Bridging Table state. This is a read-only state.
+
+
 API reference
 *************
 

subsys/bluetooth/mesh/brg_cfg.c

@@ -199,7 +199,7 @@ int bt_mesh_brg_cfg_tbl_add(enum bt_mesh_brg_cfg_dir direction, uint16_t net_idx
 {
 	/* Sanity checks */
 	if (!BT_MESH_ADDR_IS_UNICAST(addr1) || net_idx1 == net_idx2 || addr1 == addr2 ||
-	    net_idx1 > 0x03FF || net_idx2 > 0x03FF) {
+	    net_idx1 > BT_MESH_BRG_CFG_KEY_INDEX_MAX || net_idx2 > BT_MESH_BRG_CFG_KEY_INDEX_MAX) {
 		return -EINVAL;
 	}
 
@@ -267,18 +267,29 @@ void bt_mesh_brg_cfg_tbl_foreach_subnet(uint16_t src, uint16_t dst, uint16_t net
 	}
 }
 
-void bt_mesh_brg_cfg_tbl_remove(uint16_t net_idx1, uint16_t net_idx2, uint16_t addr1,
+int 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
+	/* Sanity checks */
+	if ((!BT_MESH_ADDR_IS_UNICAST(addr1) && addr1 != BT_MESH_ADDR_UNASSIGNED) ||
+	    addr2 == BT_MESH_ADDR_ALL_NODES) {
+		return -EINVAL;
+	}
+
+	if (net_idx1 == net_idx2 || net_idx1 > BT_MESH_BRG_CFG_KEY_INDEX_MAX ||
+	    net_idx2 > BT_MESH_BRG_CFG_KEY_INDEX_MAX) {
+		return -EINVAL;
+	}
+
 
 	/* 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;
+		return 0;
 	}
 
 	for (int i = 0; i < bt_mesh_brg_cfg_row_cnt; i++) {
@@ -304,4 +315,6 @@ void bt_mesh_brg_cfg_tbl_remove(uint16_t net_idx1, uint16_t net_idx2, uint16_t a
 		bt_mesh_settings_store_schedule(BT_MESH_SETTINGS_BRG_PENDING);
 	}
 #endif
+
+	return 0;
 }

subsys/bluetooth/mesh/brg_cfg.h

@@ -8,6 +8,11 @@
 #define ZEPHYR_SUBSYS_BLUETOOTH_MESH_BRG_CFG_H_
 
 /** These are internal APIs. They do not sanitize input params. */
+
+#define BT_MESH_BRG_CFG_KEY_INDEX_MAX 0x0FFF
+
+#define BT_MESH_BRG_CFG_NKEY_PRHB_FLT_MASK 0x000C
+
 enum bt_mesh_brg_cfg_dir {
 	/* Value is prohibited. */
 	BT_MESH_BRG_CFG_DIR_PROHIBITED = 0,
@@ -48,7 +53,7 @@ int bt_mesh_brg_cfg_tbl_get(const struct bt_mesh_brg_cfg_row **rows);
 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);
 
-void bt_mesh_brg_cfg_tbl_remove(uint16_t net_idx1, uint16_t net_idx2, uint16_t addr1,
+int bt_mesh_brg_cfg_tbl_remove(uint16_t net_idx1, uint16_t net_idx2, uint16_t addr1,
 				uint16_t addr2);
 
 typedef void (*bt_mesh_brg_cfg_cb_t)(uint16_t new_netidx, void *user_data);