[蓝牙 Mesh & Zephyr]-[002]-发送 Unprovisioned Device Beacon

Unprovisioned Device Beacon 格式如下：

Field	Size (octets)	Notes
Beacon Type	1	Unprovisioned Device beacon type(0x00)
Device UUID	16	Device UUID uniquely identifying this device (see Section 3.10.3)
OOB Information	2	See Table 3.54
URI Hash	4	Hash of the associated URI advertised with the URI AD Type (optional field)

Table 3.53: Unprovisioned Device beacon format

Bit	Description
0	Otehr
1	Electronic/URI
2	2D machine-readable code
3	Bar code
4	Near Field Communication(NFC)
5	Number
6	String
7	Reserved for Future Use
8	Reserved for Future Use
9	Reserved for Future Use
10	Reserved for Future Use
11	On box
12	Inside box
13	On peice of paper
14	Inside manual
15	On device

Table 3.54: OOB Information field

URI Hash：URI(Uniform Resource Identifier) 的哈希值。

在 Zephyr Mesh 中，发送 Unprovisioned Device Beacon 的函数如下：

hci.h

#define BT_DATA_URI                     0x24 /* URI */
#define BT_DATA_MESH_PROV               0x29 /* Mesh Provisioning PDU */
#define BT_DATA_MESH_MESSAGE            0x2a /* Mesh Networking PDU */
#define BT_DATA_MESH_BEACON             0x2b /* Mesh Beacon */

beacon.c

static int unprovisioned_beacon_send(void)
{
#if defined(CONFIG_BT_MESH_PB_ADV)
	const struct bt_mesh_prov *prov;
	u8_t uri_hash[16] = { 0 };
	struct net_buf *buf;
	u16_t oob_info;

	BT_DBG("");
	//BT_DATA_MESH_BEACON = 0x2b
	//最终通过adv_type[BT_MESH_ADV_BEACON] 获取 BT_DATA_MESH_BEACON,
	buf = bt_mesh_adv_create(BT_MESH_ADV_BEACON, UNPROV_XMIT, K_NO_WAIT);
	if (!buf) {
		BT_ERR("Unable to allocate beacon buffer");
		return -ENOBUFS;
	}
	/获取通过 bt_mesh_prov_init(const struct bt_mesh_prov *prov_info)配置的数据
	prov = bt_mesh_prov_get();

	net_buf_add_u8(buf, BEACON_TYPE_UNPROVISIONED);
	net_buf_add_mem(buf, prov->uuid, 16);
	//计算 URI Hash
	if (prov->uri && bt_mesh_s1(prov->uri, uri_hash) == 0) {
		oob_info = prov->oob_info | BT_MESH_PROV_OOB_URI;
	} else {
		oob_info = prov->oob_info;
	}

	net_buf_add_be16(buf, oob_info);
	net_buf_add_mem(buf, uri_hash, 4);

    //发送 buf
	bt_mesh_adv_send(buf, NULL, NULL);
	//buf引用计数减1，减到0时放回池中
	net_buf_unref(buf);
	//URI，是通过AD Type = BT_DATA_URI(0x24)发出的 
	if (prov->uri) {
		size_t len;

		buf = bt_mesh_adv_create(BT_MESH_ADV_URI, UNPROV_XMIT,
					 K_NO_WAIT);
		if (!buf) {
			BT_ERR("Unable to allocate URI buffer");
			return -ENOBUFS;
		}

		len = strlen(prov->uri);
		if (net_buf_tailroom(buf) < len) {
			BT_WARN("Too long URI to fit advertising data");
		} else {
			net_buf_add_mem(buf, prov->uri, len);
			bt_mesh_adv_send(buf, NULL, NULL);
		}

		net_buf_unref(buf);
	}

#endif /* CONFIG_BT_MESH_PB_ADV */
	return 0;
}