I am currently working on an iOS application based on bluetooth low energy devices. In order to get a unique identifier to compare the peripherals got, I have to get the MAC address of the peripherals.
It is observed that the UUID property of a peripheral device varies across iOS devices and also for the peripheral device to get a UUID, it will have to get connected to a master device at least once. Since I have to deal with check-in's I don't want to establish a connection. As I went through the bluetooth services portal, I found that the device information itself is a service, which couldn't be retrieved unless a connection has been established between the master iOS device and the peripheral bluetooth low energy device.
I found that in Android we get the entire information of the device, including its MAC address (using getAddress()) when we get the response from the device on scanning itself.
I didn't find any properties in CBPeripheral class related to the device address.
Another way to get a unique parameter would be to customize the advertisement data to send additional information regarding the device, which requires more work on firmware side.
So is there any way in iOS that I could get the MAC address of the bluetooth low energy peripheral without establishing a connection?
Any help would be greatly appreciated.
CBPeripheral's identifier property will serve your purpose, available from a still-unconnected device in CBCentralManager's didDiscoverPeripheral delegate method:
- (void)centralManager:(CBCentralManager *)central didDiscoverPeripheral:(CBPeripheral *)peripheral advertisementData:(NSDictionary *)advertisementData RSSI:(NSNumber *)RSSI
CBPeripheral *peripheral ...
NSUUID* serverId = [peripheral identifier];
I have a half dozen LE devices I'm experimenting with, including multiple sets of identical devices. I just confirmed that across two iOS devices, the identifiers for all of these LE widgets were different, but for EACH iOS device, the identifier for each widget was retained across application launches and even across app deletes and reinstalls. I would say this definitively proves that the OS is storing enough info internally that for a given iThing, you'll be able to distinguish between, and re-identify, all the peripherals your app encounters, without actually connecting to them.
Also note that the advertisementData, also available before connecting, is full of useful info like CBAdvertisementDataLocalNameKey, CBAdvertisementDataManufacturerDataKey, CBAdvertisementDataServiceUUIDsKey, CBAdvertisementDataSolicitedServiceUUIDsKey, and others, although none as certain to uniquely identify the device as [peripheral identifier] is.
I didn't try doing a device backup and restore to prove the UUIDs were retained, but I'd wager they are, and if they're not, it's something Apple would consider a bug.
Updated Answer :-
After iOS 12 we can get UDID
print(UIDevice.current.identifierForVendor)
print(UIDevice.current.identifierForVendor?.uuidString)
Before iOS 12**
There is no public API to get this information.
If this is an internal or jailbreak application you can get the value of the kLockdownBluetoothAddressKey key via liblockdown.dylib
Low energy peripherals may use privacy feature which hides the MAC address, so it is not necessarily even possible to get the address before connection or bonding. If you somehow get the MAC address which goes over the air, you need to handle privacy or you have interoperability problems.
Apple uses UUIDs to abstract these privacy features out so users do not need to worry about those.
Correct way to do that like you wrote is to either add some vendor specific data to advertisement packet or use the Device Information service.
On-behalf of the discussion of the other professionals I've found some facts which says -
“iOS hides the MAC address of the device and generates a UUID. The UUID on iOS is generated by the iOS device. Different iOS devices will get different UUIDs for the same peripheral. The MAC address is usually based on the hardware. If we both have iPhones and scan the same peripheral, we'll see different UUIDs. iOS generates the UUID on the device and hides the MAC address.
Summary - iOS doesn't let you get the MAC address of a device, it gives you a random UUID instead.“
Source - https://github.com/don/cordova-plugin-ble-central/issues/77
As per above study I've found that there’s not such a unique way to get connect to the board so far, Every board has a MAC address, which Doesn’t changes and easy to access in (only) Android, while iOS doesn’t allow to access MAC Address of the peripheral, however iOS use this MAC address to create a peripheral identifier (UUID), which is unique on (unique) device only. The peripheral identifier for a single Board is different for different iPhones devices (but unique on single device).
However we can connect to a board by searching with Peripheral's Bluetooth Service UUID, but this service UUID is same for all the boards of a kind say- “Adafruit Feather M0”. It means the App will look around the BLE boards of the same type (“Adafruit Feather M0”) and will get connect to ANY one of them. In order to connect to a particular user to a specific Board doesn’t seems to be possible so far due to the inaccessibility of MAC and giving the random UUID in iOS.
You can access to the MAC ADDRESS without problem in iOS 12.
To get the mac address you have to follow the next steps.
Parse the Data received by the BLE device to String.
extension Data{
func hexEncodedString() -> String {
let hexDigits = Array("0123456789abcdef".utf16)
var hexChars = [UTF16.CodeUnit]()
hexChars.reserveCapacity(count * 2)
for byte in self {
let (index1, index2) = Int(byte).quotientAndRemainder(dividingBy: 16)
hexChars.insert(hexDigits[index2], at: 0)
hexChars.insert(hexDigits[index1], at: 0)
}
return String(utf16CodeUnits: hexChars, count: hexChars.count)
}
}
Add a separator ":" to the address.
extension String {
func separate(every stride: Int = 4, with separator: Character = " ") -> String {
return String(enumerated().map { $0 > 0 && $0 % stride == 0 ? [separator, $1] : [$1]}.joined())
}
}
In didReadValueForCharacteristic( characteristic: CBCharacteritic) you can use the previous 2 functions to get the mac address.
func didReadValueForCharacteristic(_ characteristic: CBCharacteristic) {
if characteristic.uuid == BleDeviceProfile.MAC_ADDRESS, let mac_address = characteristic.value?.hexEncodedString().uppercased(){
let macAddress = mac_address.separate(every: 2, with: ":")
print("MAC_ADDRESS: \(macAddress)")
}
}
enjoy your mac address:
"MAC_ADDRESS: 00:0A:57:4E:86:F2"
Related
Yes, I know that there is no way to retrieve the MAC address of a BLE peripheral found by using the CoreBluetooth package, as discussed in other questions like here.
The company I'm working for has a test setup where we have different types of iPhones which should connect to different peripherals under test. For each peripheral under test, we know the MAC address. For our tests we need a specific iPhone to connect to a specific peripheral. The peripherals do differ only in their MAC address.
Since it is possible to have consistent peripheral ids on a single iOS device by using
public func centralManager(_ central: CBCentralManager, didDiscover peripheral: CBPeripheral, advertisementData: [String : Any], rssi RSSI: NSNumber) {
let id = peripheral.identifier
}
we create a mapping table for each peripheral and each iPhone. Thus, we have a function similar to this one: (we don't use this one, but you get the idea)
func getMAC(peripheralId: String, iPhoneID: String) -> String {
if iPhoneID == "iPhoneFoo" && peripheralId == "uuid-peripheralFoo-iPhoneFoo" {
return "MAC-peripheralFoo"
}
else if iPhoneID == "iPhoneFoo" && peripheralId == "uuid-peripheralBar-iPhoneFoo" {
return "MAC-peripheralBar"
}
else if iPhoneID == "iPhoneBar" && peripheralId == "uuid-peripheralFoo-iPhoneBar" {
return "MAC-peripheralFoo"
}
else if iPhoneID == "iPhoneBar" && peripheralId == "uuid-peripheralBar-iPhoneBar" {
return "MAC-peripheralBar"
}
else {
return "unkown"
}
}
We use the output of this function to check if a found peripheral matches the MAC address it should search for.
As you can guess, it is very tedious to make this mapping function, especially, if new iPhones or new peripherals enter the test setup.
My question is now: Is there a way to "calculate" the peripheral Id of a device if you know the MAC address beforehand?
So something like a function, where you provide the MAC address and retrieve the uuid, as if a device was actually found by performing a BLE scan?
Thanks in advance!
No, there isn't. The Bluetooth device address can't be used alone to get the uuid device identifier. In fact, the identifier will be different depending on which phone you use to scan.
As Emil notes, the identifier will be different on different phones. It can even change on the same phone. Peripheral IDs are not promised to be stable and they do change from time to time. There is no way to uniquely identify an arbitrary device when you don't control the firmware. (And if you find a way, expect Apple to break it eventually. They hide this stuff on purpose to prevent user tracking.)
If you do control the firmware, I recommend putting identifying information in the advertising data. I personally generally put identifiers in the manufacturers data, but for your situation the Local Name is probably the most convenient (and may even be settable for firmware you don't control). There are tons of other solutions. I even advertised per-device service UUIDs in one project (this is nice because it means you can easily limit your scanForPeripherals call to look for specific devices in the background).
If you go down this road (assuming you control your firmware), be very thoughtful about user privacy if you store an identifier in the advertising packet. Anything that doesn't change can allow your users to be tracked. There are various good solutions to this problem. I generally base mine on the IRK system that BLE uses to hide MAC addresses. (This may not impact you because this seems to be for internal testing, but I always want to warn people about the privacy concerns of long-lived identifiers.)
I have two BLE circuit boards (custom built by my company) that are advertising. When I scan, they are identified as the same CBPeripheral despite having different names and identifiers. Here's my console readout of the delegate call:
centralManager didDiscoverPeripheral <CBPeripheral: 0x144d26c70, identifier = E0FE60A5-FC4A-A6C5-3868-7D0EEAA580CD, name = Board A3D43, state = disconnected>
centralManager didDiscoverPeripheral <CBPeripheral: 0x144d26c70, identifier = 2209CC24-05E8-8455-3A40-3F27AE9078DB, name = Board 51EB5E, state = disconnected>
My question is how are CBPeripherals differentiated, if not by name or identifier? Our firmware uses Bluetopia under the hood, perhaps there's some incomplete serialization in there?
As Paul mentioned in his comment, the memory addresses didn't end up being relevant to this problem. The core problem was that the peripherals were generating identical IRKs, which caused iOS to mistakenly think they were all the same peripheral. The error stemmed from a false assumption that the key diversifying function (d1 in core BT spec, vol 3 part H 5.2.2.1) had a randomness component, when in fact it's just a hashing function.
We were able to verify success on this by looking at the Settings app - before the change, when we connected a new peripheral, it overwrote the previous pairing in Bluetooth settings. Once we made the IRKs unique we saw multiple devices listed in the Settings app.
I know you can use this service to have devices like smart watches intercept notifications from iOS devices. But can you receive these iOS notifications on a Mac through OS X?
I want to be able to have my OS X program detect a specific notification type that is received in iOS. I tried browsing for the ANCS device on my Mac, but it didn't show up. I know you can't do this between iOS devices, so I was wondering if maybe the same was true between iOS and OS X or not?
Thanks!
It's definitely possible!
Here's what you need:
An app on your iOS device which imports CoreBluetooth and uses CBPeripheralManager to advertise a dummy service with some custom UUID (not the ANCS UUID, it won't work). This dummy service is required for your Mac to "see" the ANCS service.*
An app on your Mac which imports IOBluetooth, initiates a CBCentralManager object, and starts a scan. You can do this as so:
[self.centralManager scanForPeripheralsWithServices:#[[CBUUID UUIDWithString:YOUR_CUSTOM_SERVICE_UUID]] options:#{CBCentralManagerScanOptionSolicitedServiceUUIDsKey:#[[CBUUID UUIDWithString:ANCS_SERVICE_UUID]]];
Make sure you set yourself up as a delegate to CBCentralManager to receive the delegate callbacks.
When your Mac discovers your device in didDiscoverPeripheral, connect to it:
[self.centralManager connectPeripheral:peripheral options:nil];
1 very important thing to note here is you need to retain your peripheral to a property if you wish to connect to it, otherwise it will be dealloc'ed. See this answer for a more detailed discussion.
In didConnectPeripheral, you need to set yourself up as a delegate to the CBPeripheral you're connected to then start discovering services:
[peripheral discoverServices:nil];
(All the callbacks from this point onward are for CBPeripheral)
In didDiscoverServices, you should get a list of available services. Loop through them as so and discover each service's characteristics:
for (CBService *service in peripheral.services) {
if ([service.UUID isEqual:[CBUUID UUIDWithString:YOUR_CUSTOM_SERVICE_UUID]]) {
NSLog(#"Found your Custom Service");
}
if ([service.UUID isEqual:[CBUUID UUIDWithString:ANCS_UUID]]) {
NSLog(#"Found ANCS Service");
}
[peripheral discoverCharacteristics:nil forService:service];
}
In didDiscoverCharacteristicsForService, you want to look for 3 characteristics:
ANCS Notification Source: UUID 9FBF120D-6301-42D9-8C58-25E699A21DBD (notifiable)
ANCS Control Point: UUID 69D1D8F3-45E1-49A8-9821-9BBDFDAAD9D9 (writeable with response)
ANCS Data Source: UUID 22EAC6E9-24D6-4BB5-BE44-B36ACE7C7BFB (notifiable)
For those notifiable characteristics, subscribe to them for updates:
if ([characteristic.UUID isEqual:[CBUUID UUIDWithString:ANCS_CHARACTERISTIC_UUID]]) {
[peripheral setNotifyValue:YES forCharacteristic:characteristic];
}
If you want to check if those characteristics are have started notifying, do a if(characteristic.isNotifying) in didUpdateNotificationStateForCharacteristic.
You will get the actual NSData updates in didUpdateValueForCharacteristic with characteristic.value. The important thing to note here is that you will get informed of notification events by the Notification Source characteristic, but these will not contain that much information. If you want your Mac to play a sound or flash some Hue lights or something like that for every iOS notification, this will suffice. However, for the actual notification details, it will need to come from the Data Source characteristic, but you need to request for them by making very specific calls to the Control Point characteristic. This is where it gets really complicated, and you'll be able to get more information in the official ANCS Specification document.
If you want a shortcut or a look at how others have done it, check out these Github repos:
jamiepinkham/BTLE_ANCS
KhaosT/ANCS-Mac
indragiek/INDANCSClient
Just be careful as you may find bugs in some of these implementations, mainly in the processing of data sent by the ANCS Data Source (I had to get creative with my own error handling).
*** Some may argue that you can use "Service Solicitation" to expose ANCS without having an app running on the iOS device and/or without advertising a dummy Service (see options parameter in Step 2), but I haven't had that much success with it so perhaps there's something I'm missing.
What I am trying to do
I am trying to connect my app to a Bluetooth LE device which needs to be paired.
Current behaviour
There is no problem without pairing the device and my iPhone application. I am able to connect, reconnect and read/write characteristics without any problem.
But, if the device need to be paired, I am only able to read/write characteristics the first time, right after the pairing popup confirmation. The next time, I discover and connect the app to my device, but I don't have the rights to read/write characteristics data because (I guess) I am not using the pairing information.
Finally...
After spending few hours searching around the web with no luck here are my questions :
How can I connect my app to a Bluetooth LE device from my iPhone app using the pairing data stored in my phone? Am I missing something?
Is it possible that it is not an IOS problem because if pairing data are present in the phone for the connecting device, it is automatically used?
Is there someone with experience with Bluetooth LE and IOS to help me?
Update 2013-10-27
I have discovered that you can't read a protected characteristic by pairing authentication right after that the characteristic has been discovered if a pairing exists (no confirmation popup). No problem with non-protected characteristic! I don't know exactly why is happening, but the behavior is that the IOS app never receive answers from the device.
So if the first reading is done after, it doesn't cause problem. Here is the code I am using to discover characteristics with the data reading in comment.
- (void) peripheral:(CBPeripheral *)peripheral didDiscoverCharacteristicsForService:(CBService *)service error:(NSError *)error;
{
NSArray *characteristics = [service characteristics];
CBCharacteristic *characteristic;
if (peripheral != servicePeripheral) {
NSLog(#"Wrong Peripheral.\n");
return ;
}
if (service != batteryService) {
NSLog(#"Wrong Service.\n");
return ;
}
if (error != nil) {
NSLog(#"Error %#\n", error);
return ;
}
for (characteristic in characteristics) {
NSLog(#"discovered characteristic %#", [characteristic UUID]);
if ([[characteristic UUID] isEqual:[CBUUID UUIDWithString:kBatteryCharacteristicUUIDString]]) { // Bat
NSLog(#"Discovered Bat Characteristic");
batteryCharacteristic = [characteristic retain];
//--> generate problem when pairing exists between IOS app and device
//[peripheral readValueForCharacteristic:batteryCharacteristic];
}
}
}
You don't have to do anything in your app for pairing management.
If your app runs in LE Central mode, and the peripheral sends an Insufficient Authentication error code in response to a read / write request, iOS will automatically pair with your device and will retry the request.
If you disconnect from the device, and later reconnect again, the peripheral needs to send the Insufficient Authentication error code again for the iPhone to restart encryption. Again, you don't have to do anything special in your app here.
If your app runs in LE Peripheral mode, things are a bit different. When you set up your GATT database, make sure to set correct flags for both the CBAttributePermissions and CBCharacteristicProperties. This will tell iOS that it should send the Insufficient Authentication error code itself, if it is not paired. It is then the responsibility of the central device to start the encryption process.
In the Bluetooth Accessory Design Guidelines for Apple Products, further restrictions are described.
Your accessory needs the capability to resolve private Bluetooth addresses. The iPhone will change its public Bluetooth address every now and then, and only paired devices will have the correct key to resolve that public address and recognize the iPhone.
"Section 3.9 Pairing" is also interesting.
Note that if you pair without man-in-the-middle (MITM) protection, your peripheral can use the resulting key to resolve the private Bluetooth address of the iPhone. However, you won't be able to encrypt the channel.
Pairing with MITM protection on iOS involves entering a PIN code that is displayed by the remote device. Out-of-band (OOB) pairing where you send pairing data over an external channel is not supported by iOS as far as I know (at least there's no public APIs to set OOB data).
Long story short: if you have only a "Pair" / "Cancel" pairing, you cannot encrypt the LE channel but only recognize the iPhone in future connections. The nice thing is that you can still recognize the iPhone even if you unpair it on the iPhone side, and even after restoring the iPhone firmware ;-).
Regarding LE encryption in general: it's not secure anyways (see http://eprint.iacr.org/2013/309).
I have an app that simulates heart rate monitor peripheral (The peripheral app).
I also have an app that receives the data and present it (The central app).
The central app decided to connect to the discovered peripheral based on its name.
The problem is that both app work perfectly good, except that the name is always "iPhone".
The advertising is done this way:
- (IBAction)switchChanged:(id)sender
{
if (self.advertisingSwitch.on) {
NSDictionary *advData =
#{CBAdvertisementDataLocalNameKey:#"Custom Name",
CBAdvertisementDataServiceUUIDsKey:#[[CBUUID UUIDWithString:#"180D"]]};
[self.peripheralManager startAdvertising:advData];
NSLog(#"Advertising");
}
else {
[self.peripheralManager stopAdvertising];
[[self timerInterval] invalidate];
NSLog(#"Stopped advertising");
}
}
But on the central side, inside
- (void) centralManager:(CBCentralManager *)central didDiscoverPeripheral:(CBPeripheral *)aPeripheral advertisementData:(NSDictionary *)advertisementData RSSI:(NSNumber *)RSSI
The name property never changed.
Is there anything that should be done?
What I have observed with CBPeripheral.name is that the device will, in fact, set the name to the name you select with CBAdvertisementDataLocalNameKey. This name is not persistent, though. If you disconnect the master and reconnect,the name will generally have been switched to "iPhone". If the peripheral disconnects due to an error, I have seen it reconnect with the correct peripheral name, but a new UUID.
There may be other situations where the name also switches to iPhone.
This appears to be a bug in iOS. I'm looking for confirmation before reporting it.
CBAdvertisementDataLocalNameKey only change kCBAdvDataLocalName in advertisementData.
When you nslog advertisementData, you will see some data like this:
{
kCBAdvDataIsConnectable = 1;
kCBAdvDataLocalName = Custom Name;
kCBAdvDataServiceUUIDs = (
"FB694B90-F49E-4597-8306-171BBA78F846"
);
}
Unfortunately, there is no other way to set the peripheral name. iPhone will always have the name: iPhone.
The advertisement is probably correctly seen on the central side. You may check by NSLogging the advertisementData. However, if you rely on the peripheral.name property, then that will either be empty (if you connect first) or contain the "iPhone" string.
I remember it is used to happen to me and I figured it was something to do with the way Core Bluetooth handles caching and service discovery. What Happened to me was that at first I received a default name like iPhone, iPad or nothing at all. But then after discovering services or trying to establish a connection the key magically changes to the value I had set on the other end.
Moreover, it seems it only happens the first time, afterwards, even between launches and subsequent runs of the app Core Bluetooth will try its best to return those values to you on the advertisement stage even on first discovery, but those might as well be outdated values.
my current implementation looks as follows:
NSString * baconName = [[UIDevice currentDevice] name];
NSDictionary *advertisementData = #{CBAdvertisementDataServiceUUIDsKey:#[[CBUUIDUUIDWithString:BACON_SERVICE_UUID]],
CBAdvertisementDataLocalNameKey:baconName};
And It just works for me, iPhones love Bacon, everybody does ;).
Hence, the best way to ensure you get any data you want, is to create another characteristic to transmit your flag and do constant discoveries of services and characteristics for Peripherals you are discovering, and accordingly minimise the discovery of existing or cached peripherals by caching or keeping a reference to them, CB is supposed to do this for ya, and they do their best effort but only you know the business logic of your app and what is important to you. I am overly paranoid and keep references to the discovered peripherals I am interested all the time. That is just me: it ensures I have the right information, and that I minimise scanning and constant re discovery of services and characteristics.
I Hope this helps.
In most such applications instead of identifying the peripheral by name, the client app should be identifying it by a service ID, and the server (peripheral), should be providing a either a standard service ID, as defined at bluetooth.org, or a proprietary service ID/name.
I have the same problem. I argee with Mike, this really seems like bug in IOS. If you discover your peripheral with TI multitool (for example) first, then your device will be discovered as you setuped in CBAdvertisementDataLocalNameKey.
to Dan1one:
you should use [[UIDevice currentDevice] model], not name, to get the string same to default.