nRF5340 BLE Filter scan required(whitelist) dose not working...

RE: nRF5340 BLE Filter scan required(whitelist) dose not working...

Taron — Thu, 18 May 2023 00:46:54 GMT

I solved it. thank you so much~

RE: nRF5340 BLE Filter scan required(whitelist) dose not working...

Taron — Wed, 17 May 2023 00:16:06 GMT

Then how many address can i advertise with directed mode?

all bonded address is possible?

RE: nRF5340 BLE Filter scan required(whitelist) dose not working...

Einar Thorsrud — Tue, 16 May 2023 13:54:40 GMT

[quote user="Taron"]2. only bonded device can connect without scan[/quote]

It is impossible to connect without scanning. In order to connect, the peripheral must advertise, and the central must scan. Then, it can connect aver receiving a advertising packet. This is how Bluetooth LE works. However, using filter accept list, only devices in the accept list (which in practice normally means bonded devices), will be allowed to connect.

[quote user="Taron"]when some device scan, it shouldn't be found any information.[/quote]

As mentioned before, this is only possible with directed advertising. But if the key is to not leak information to other bluetooth devices that are scanning, it would be better to simply not include information you don't want other than the bonded peer(s) to know in the advertising packet. After all, a sniffer will be able to pick up all also directed advertising packets).

RE: nRF5340 BLE Filter scan required(whitelist) dose not working...

Taron — Tue, 16 May 2023 08:13:42 GMT

Yep, i applied this function.

and i checked BT_LE_ADV_OPT_DIR_ADDR_RPA mode.

i want to make to like ble of car.

1. bonding central device

-> i got the bonded device list with bt_foreach_bond()

2. only bonded device can connect without scan, when some device scan, it shouldn't be found any information.

-> when i use BT_LE_ADV_OPT_DIR_ADDR_RPA mode, only 1 device can connect without other bonded device.

Do you have any idea?

I attached other files.

Please help me..

devzone.nordicsemi.com/.../5127.prj.conf devzone.nordicsemi.com/.../76581.main.c

RE: nRF5340 BLE Filter scan required(whitelist) dose not working...

Einar Thorsrud — Mon, 15 May 2023 09:15:42 GMT

Like you do in the code you posted in the original code, where you use bt_foreach_bond() to iterate through all bonds. There you also get the address. Specifically, this is the callback in the code you posted:

static void add_bonded_addr_to_filter_list(const struct bt_bond_info *info, void *data)
{
	char addr_str[BT_ADDR_LE_STR_LEN];

	bt_le_filter_accept_list_add(&info->addr);
	bt_addr_le_to_str(&info->addr, addr_str, sizeof(addr_str));
	printk("Added %s to advertising accept filter list\n", addr_str);
	bond_count++;
}

And here you get the address of the bonded device as &info->addr.

RE: nRF5340 BLE Filter scan required(whitelist) dose not working...

Taron — Mon, 15 May 2023 09:10:14 GMT

I'm so sorry, i have last question.

how can i get the bonded device address?

RE: nRF5340 BLE Filter scan required(whitelist) dose not working...

Taron — Mon, 15 May 2023 08:51:47 GMT

Okay, i understand it. Thank you so much~

RE: nRF5340 BLE Filter scan required(whitelist) dose not working...

Einar Thorsrud — Mon, 15 May 2023 08:46:59 GMT

Hi,

[quote user="Taron"]Oh i see. I got it, that mean filter accept list affect only connecting right?[/quote]

Yes. When advertising with filter accept list, any connection attempts by centrals not in the list will simply be ignored.

[quote user="Taron"]when peripheral device stop advertising, can bonded device connect to peripheral device?[/quote]

No, the peripheral listens for connections in a very short time right after sending an advertising packet, and that is the only time. It is not possible for a central to connect to a peripheral that is not advertising.

RE: nRF5340 BLE Filter scan required(whitelist) dose not working...

Taron — Mon, 15 May 2023 08:22:05 GMT

I have more question.

when peripheral device stop advertising, can bonded device connect to peripheral device?

if you have any solution, can you tell me?

RE: nRF5340 BLE Filter scan required(whitelist) dose not working...

Taron — Mon, 15 May 2023 07:49:06 GMT

Oh i see. I got it, that mean filter accept list affect only connecting right?

RE: nRF5340 BLE Filter scan required(whitelist) dose not working...

Einar Thorsrud — Mon, 15 May 2023 07:41:30 GMT

Hi,

Any central can still scan the peripheral when you use filter accept list. However, only devices in the filter list (previously called whitelist) are allowed to connect.

The only way you can prevent other centrals from scanning a peripheral is to use directed advertising, where you explicitly advertise specifically to a central. That is generally not recommended though, and for instance Apple writes this in the Accessory Design Guidelines for Apple Devices:

ADV_DIRECT_IND should not be used.

Also, note that a sniffer can still read the packets, it is just that the Bluetooth stacks of the central will filter out directed advertising packets that are intended for other devices. That said, if you really need this, then you can take a look at the Bluetooth: Direct Advertising sample.

RE: nRF5340 BLE Filter scan required(whitelist) dose not working...

Taron — Mon, 15 May 2023 00:07:56 GMT

Hi,

I understand bt_foreach_bond fuction.

Actually i want to the center device can't scan my advertising without bonded device(whitelist adding device).

But When i change the advertising option BT_LE_ADV_OPT_FILTER_SCAN_REQ, then it's not working.

I mean every device can scan my advertising.

It's my problem.

Thanks

RE: nRF5340 BLE Filter scan required(whitelist) dose not working...

Einar Thorsrud — Fri, 12 May 2023 12:02:55 GMT

Hi,

In what way does this not work?

Looking at your main.c that is one thing that sticks out. You have a bond_count variable set to 0, and this is always 0. The reason is that you have this line:

	bt_foreach_bond(BT_ID_DEFAULT, add_bonded_addr_to_filter_list, NULL);

which probably should change to this:

	bt_foreach_bond(BT_ID_DEFAULT, add_bonded_addr_to_filter_list, &bond_count);

You can see more about how to use the filter accept list in Exercise 2 in Lesson 5 of the Bluetooth Low Energy Fundamentals course.