bt: services: gap_default: Extract GAP service from gatt implementation

include/zephyr/bluetooth/gap.h

@@ -26,6 +26,15 @@ extern "C" {
  * @{
  */
 
+/**
+ * @brief Default GAP service name
+ *
+ * Use this name as a first argument for BT_GATT_SERVICE_DEFINE when creating
+ * GAP service implementation.
+ * This ensures that the GAP service would be placed just after BT_UUID_GATT.
+ */
+#define BT_GATT_GAP_SVC_DEFAULT_NAME _2_gap_svc
+
 /**
  * @name Company Identifiers (see Bluetooth Assigned Numbers)
  * @{

samples/bluetooth/peripheral_gap_svc/CMakeLists.txt

@@ -0,0 +1,7 @@
+cmake_minimum_required(VERSION 3.20.0)
+find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
+project(peripheral_gap_svc)
+
+target_sources(app PRIVATE
+        src/main.c
+)

samples/bluetooth/peripheral_gap_svc/README.rst

@@ -0,0 +1,29 @@
+.. zephyr:code-sample:: ble_peripheral_gap_svc
+   :name: Peripheral GAP Server non default implementation
+   :relevant-api: bluetooth
+
+   Implement a dummy peripheral with GAP Server that limits the accepted names
+
+Overview
+********
+
+This sample demonstrates the implementation of the GAP service
+
+
+
+
+This sample demonstrates the usage of the NUS service (Nordic UART Service) as a serial
+endpoint to exchange data. In this case, the sample assumes the data is UTF-8 encoded,
+but it may be binary data. Once the user connects to the device and subscribes to the TX
+characteristic, it will start receiving periodic notifications with "Hello World!\n".
+
+Requirements
+************
+
+* BlueZ running on the host, or
+* A board with Bluetooth LE support
+
+Building and Running
+********************
+
+See :zephyr:code-sample-category:`bluetooth` samples for details.

samples/bluetooth/peripheral_gap_svc/prj.conf

@@ -0,0 +1,14 @@
+CONFIG_LOG=y
+CONFIG_BT=y
+CONFIG_BT_SMP=y
+CONFIG_BT_PERIPHERAL=y
+
+# Testing locally redefined SVC implementation
+CONFIG_BT_GAP_SVC_DEFAULT_IMPL=n
+
+CONFIG_BT_DEVICE_NAME="Zephyr GAP service"
+CONFIG_BT_DEVICE_NAME_DYNAMIC=y
+CONFIG_BT_DEVICE_NAME_GATT_WRITABLE=y
+
+CONFIG_BT_DEVICE_APPEARANCE_DYNAMIC=n
+CONFIG_BT_DEVICE_APPEARANCE_GATT_WRITABLE=n

samples/bluetooth/peripheral_gap_svc/sample.yaml

@@ -0,0 +1,14 @@
+sample:
+  name: Bluetooth Peripheral GAP service non default implementation
+  description: Demonstrates the GAP service implementation on application side.
+tests:
+  sample.bluetooth.peripheral_gap_svc:
+    harness: bluetooth
+    platform_allow:
+      - qemu_cortex_m3
+      - qemu_x86
+      - nrf52840dk/nrf52840
+      - ophelia4ev/nrf54l15/cpuapp
+    integration_platforms:
+      - qemu_cortex_m3
+    tags: bluetooth

samples/bluetooth/peripheral_gap_svc/src/main.c

@@ -0,0 +1,157 @@
+/*
+ * Copyright (c) 2025 Koppel Electronic
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <zephyr/kernel.h>
+#include <zephyr/bluetooth/bluetooth.h>
+#include <zephyr/sys/byteorder.h>
+#include <zephyr/bluetooth/gatt.h>
+
+
+#define DEVICE_NAME		CONFIG_BT_DEVICE_NAME
+#define DEVICE_NAME_LEN		(sizeof(DEVICE_NAME) - 1)
+
+static const struct bt_data ad[] = {
+	BT_DATA_BYTES(BT_DATA_FLAGS, (BT_LE_AD_GENERAL | BT_LE_AD_NO_BREDR)),
+	BT_DATA(BT_DATA_NAME_COMPLETE, DEVICE_NAME, DEVICE_NAME_LEN),
+};
+
+/* -----------------------------------------------------------------------------
+ * Local implementation of GAP service
+ */
+
+static ssize_t read_name(struct bt_conn *conn, const struct bt_gatt_attr *attr,
+			 void *buf, uint16_t len, uint16_t offset)
+{
+	const char *name = bt_get_name();
+
+	return bt_gatt_attr_read(conn, attr, buf, len, offset, name,
+				 strlen(name));
+}
+
+static ssize_t write_name(struct bt_conn *conn, const struct bt_gatt_attr *attr, const void *buf,
+			  uint16_t len, uint16_t offset, uint8_t flags)
+{
+	/* adding one to fit the terminating null character */
+	char value[CONFIG_BT_DEVICE_NAME_MAX + 1] = {};
+
+	if (offset != 0) {
+		return BT_GATT_ERR(BT_ATT_ERR_INVALID_OFFSET);
+	}
+
+	if (offset + len > CONFIG_BT_DEVICE_NAME_MAX) {
+		return BT_GATT_ERR(BT_ATT_ERR_INVALID_ATTRIBUTE_LEN);
+	}
+
+	memcpy(value, buf, len);
+
+	value[len] = '\0';
+
+	/* Check if the name starts with capital letter */
+	if (value[0] < 'A' || value[0] > 'Z') {
+		printk("Rejected name change to \"%s\": must start with capital letter\n", value);
+		return BT_GATT_ERR(BT_ATT_ERR_VALUE_NOT_ALLOWED);
+	}
+
+	bt_set_name(value);
+
+	printk("Name changed to \"%s\"\n", value);
+
+	return len;
+}
+
+static ssize_t read_appearance(struct bt_conn *conn,
+			       const struct bt_gatt_attr *attr, void *buf,
+			       uint16_t len, uint16_t offset)
+{
+	uint16_t appearance = sys_cpu_to_le16(bt_get_appearance());
+
+	return bt_gatt_attr_read(conn, attr, buf, len, offset, &appearance, sizeof(appearance));
+}
+
+BT_GATT_SERVICE_DEFINE(BT_GATT_GAP_SVC_DEFAULT_NAME,
+	BT_GATT_PRIMARY_SERVICE(BT_UUID_GAP),
+	/* Require pairing for writes to device name */
+	BT_GATT_CHARACTERISTIC(BT_UUID_GAP_DEVICE_NAME,
+			       BT_GATT_CHRC_READ | BT_GATT_CHRC_WRITE,
+			       BT_GATT_PERM_READ | BT_GATT_PERM_WRITE,
+			       read_name, write_name, NULL),
+	BT_GATT_CHARACTERISTIC(BT_UUID_GAP_APPEARANCE,
+			       BT_GATT_CHRC_READ,
+			       BT_GATT_PERM_READ,
+			       read_appearance, NULL, NULL),
+);
+
+/* End of local implementation of GAP service
+ * ---------------------------------------------------------------------------
+ */
+
+static void connected(struct bt_conn *conn, uint8_t conn_err)
+{
+	char addr[BT_ADDR_LE_STR_LEN];
+
+	bt_addr_le_to_str(bt_conn_get_dst(conn), addr, sizeof(addr));
+
+	if (conn_err) {
+		printk("Failed to connect to %s (%u)\n", addr, conn_err);
+		return;
+	}
+
+	printk("Connected: %s\n", addr);
+}
+
+static void disconnected(struct bt_conn *conn, uint8_t reason)
+{
+	char addr[BT_ADDR_LE_STR_LEN];
+
+	bt_addr_le_to_str(bt_conn_get_dst(conn), addr, sizeof(addr));
+
+	printk("Disconnected: %s (reason 0x%02x)\n", addr, reason);
+}
+
+static int start_advertising(void)
+{
+	int err;
+
+	err = bt_le_adv_start(BT_LE_ADV_CONN_FAST_1, ad, ARRAY_SIZE(ad), NULL, 0);
+	if (err) {
+		printk("Advertising failed to start (err %d)\n", err);
+	}
+
+	return err;
+}
+
+static void recycled(void)
+{
+	start_advertising();
+}
+
+BT_CONN_CB_DEFINE(conn_callbacks) = {
+	.connected = connected,
+	.disconnected = disconnected,
+	.recycled = recycled,
+};
+
+int main(void)
+{
+	int err;
+
+	printk("Sample - Bluetooth Peripheral GAP service\n");
+
+	err = bt_enable(NULL);
+	if (err) {
+		printk("Failed to enable bluetooth: %d\n", err);
+		return err;
+	}
+
+	err = start_advertising();
+	if (err) {
+		return err;
+	}
+
+	printk("Initialization complete\n");
+
+	return 0;
+}

subsys/bluetooth/host/CMakeLists.txt

@@ -49,6 +49,11 @@ if(CONFIG_BT_HCI_HOST)
       gatt.c
       )
 
+    zephyr_library_sources_ifdef(
+      CONFIG_GATT_GAP_SVC_VALIDATE
+      gatt_gap_svc_validate.c
+      )
+
     if(CONFIG_BT_SMP)
       zephyr_library_sources(
         smp.c

subsys/bluetooth/host/Kconfig.gatt

@@ -259,62 +259,6 @@ config BT_PERIPHERAL_PREF_TIMEOUT
 	  Range 3200 to 65534 is invalid. 65535 represents no specific value.
 endif # BT_GAP_PERIPHERAL_PREF_PARAMS
 
-config BT_DEVICE_NAME_GATT_WRITABLE
-	bool "Allow to write device name by remote GATT clients"
-	depends on BT_DEVICE_NAME_DYNAMIC
-	default y
-	help
-	  Enabling this option allows remote GATT clients to write to device
-	  name GAP characteristic.
-
-if BT_DEVICE_NAME_GATT_WRITABLE
-choice BT_DEVICE_NAME_GATT_WRITABLE_SECURITY
-	prompt "Security requirements"
-	default DEVICE_NAME_GATT_WRITABLE_ENCRYPT
-	help
-	  Select security requirements for writing device name by remote GATT
-	  clients.
-
-config DEVICE_NAME_GATT_WRITABLE_NONE
-	bool "No requirements"
-
-config DEVICE_NAME_GATT_WRITABLE_ENCRYPT
-	bool "Encryption required"
-
-config DEVICE_NAME_GATT_WRITABLE_AUTHEN
-	bool "Encryption and authentication required"
-
-endchoice  #BT_DEVICE_NAME_GATT_WRITABLE_SECURITY
-endif #BT_DEVICE_NAME_GATT_WRITABLE
-
-config BT_DEVICE_APPEARANCE_GATT_WRITABLE
-	bool "Allow to write GAP Appearance by remote GATT clients"
-	depends on BT_DEVICE_APPEARANCE_DYNAMIC
-	default y
-	help
-	  Enabling this option allows remote GATT clients to write to device
-	  appearance GAP characteristic.
-
-if BT_DEVICE_APPEARANCE_GATT_WRITABLE
-choice BT_DEVICE_APPEARANCE_GATT_WRITABLE
-	prompt "Security requirements"
-	default DEVICE_APPEARANCE_GATT_WRITABLE_AUTHEN
-	help
-	  Select security requirements for writing device name by remote GATT
-	  clients.
-
-config BT_DEVICE_APPEARANCE_GATT_WRITABLE_NONE
-	bool "No requirements"
-
-config BT_DEVICE_APPEARANCE_GATT_WRITABLE_ENCRYPT
-	bool "Encryption required"
-
-config DEVICE_APPEARANCE_GATT_WRITABLE_AUTHEN
-	bool "Encryption and authentication required"
-
-endchoice  #BT_DEVICE_APPEARANCE_GATT_WRITABLE
-endif #BT_DEVICE_APPEARANCE_GATT_WRITABLE
-
 config BT_GATT_AUTHORIZATION_CUSTOM
 	bool "Custom authorization of GATT operations"
 	help
@@ -323,4 +267,5 @@ config BT_GATT_AUTHORIZATION_CUSTOM
 	  with the bt_gatt_authorization_cb_register API. See the API
 	  documentation for more details.
 
+rsource 'Kconfig.gatt_gap_svc_validate'
 endmenu

subsys/bluetooth/host/Kconfig.gatt_gap_svc_validate

@@ -0,0 +1,21 @@
+# Bluetooth GATT GAP service validation
+
+# Copyright (c) 2025 Koppel Electronic
+# SPDX-License-Identifier: Apache-2.0
+
+menuconfig GATT_GAP_SVC_VALIDATE
+	bool "GATT GAP Service validation"
+	depends on BT_CONN
+	default y
+	help
+	  Validate if in the GATT database exactly one GAP service is present.
+	  This helps to debug any issues related to GAP service that may make
+	  the Bluetooth implementation not compatible with the standard.
+
+if GATT_GAP_SVC_VALIDATE
+
+module = GATT_GAP_SVC_VALIDATE
+module-str = gatt-gap-validate
+source "subsys/logging/Kconfig.template.log_config"
+
+endif # GATT_GAP_SVC_VALIDATE

subsys/bluetooth/host/conn.c

@@ -53,6 +53,7 @@
 #include "common/bt_str.h"
 #include "conn_internal.h"
 #include "direction_internal.h"
+#include "gatt_gap_svc_validate.h"
 #include "hci_core.h"
 #include "id.h"
 #include "iso_internal.h"
@@ -4428,6 +4429,14 @@ int bt_conn_init(void)
 
 	bt_att_init();
 
+	if (IS_ENABLED(CONFIG_GATT_GAP_SVC_VALIDATE)) {
+		err = gatt_gap_svc_validate();
+		if (err) {
+			LOG_ERR("GATT GAP service validation failed (err %d)", err);
+			return err;
+		}
+	}
+
 	err = bt_smp_init();
 	if (err) {
 		return err;