Reading IRK and gap_evt.params.connected.irk_match issue

[Valer_I]

Hello all, I have implemented own bond manager with saving context to flash on nRF51422 SD110. The problem is in getting IRK and creating a whitelist with it after disconnection. As far as I understand,

at BLE_GAP_EVT_CONNECTED I get &ble_evt->evt.gap_evt.params.connected.peer_addr.addr_type == BLE_GAP_ADDR_TYPE_RANDOM_PRIVATE_RESOLVABLE so IRK will be used to resolve central address.

at BLE_GAP_EVT_SEC_PARAMS_REQUEST we provide pointer to data structure where the IRK will be stored after BLE_GAP_EVT_AUTH_STATUS received

...
keys_exchanged.keys_central.p_id_key   = 
&m_peer_table[m_connection_table[index].bonded_dev_id].peer_id; 
...
err_code = sd_ble_gap_sec_params_reply(p_ble_evt->evt.gap_evt.conn_handle,
                                                   BLE_GAP_SEC_STATUS_SUCCESS,
                                                   &m_application_table[0].sec_param, 
                                                   &keys_exchanged);

at BLE_GAP_EVT_AUTH_STATUS I read m_peer_table and IRK remains blank. The .id_bitmap changed.

Than, after reconnection
_ble_evt->evt.gap_evt.params.connected.irk_match ==0 I create whitelist with presaved .id_bitmapthat states that IRK present. Device start advertice with whitelist (like with IRK) but all devices able see this advertising and connect/bond to device.

What should I do to get IRK? May be any example available?

[Petter Myhre]

Your approach seems correct. Do you have a sniffer trace?

[Valer_I]

Not yet, now I only have PCA10000 board abd able to receive only ADV_IND packets, I'll try to found the sniffer board.
I also have a few questions to fill the blanks in my understanding of adverticement procedure: but I ask them in separate thread. Thank you, Petter.

[Petter Myhre]

I don't want to be a fusspot, but could you add unrelated questions separately? Thank you.

[Valer_I]

Solved,

m_application_table[0].sec_param.kdist_central.enc  = 0;
m_application_table[0].sec_param.kdist_central.id   = 1; 
m_application_table[0].sec_param.kdist_central.sign = 0; 
m_application_table[0].sec_param.kdist_periph.enc   = 1;
m_application_table[0].sec_param.kdist_periph.id    = 1;
m_application_table[0].sec_param.kdist_periph.sign  = 0;

After setting kdist_central.id = 1; the central become to send IRK and whitelist now works both with address and IRKs. I ask Nordic team to prepare the tutorial not only for beginers to save time of developers and support emploees ;).

[rohit]

Hello,

I have the same problem where the central connects with a PRIVATE_RESOLVABLE_ADDRESS, and I wish to discover the IRK needed to populate whitelist at a peripheral.

I also see the following in my connection event:

ble_evt->evt.gap_evt.params.connected.irk_match ==0

Reading this thread, it is not clear to me what must be done to fetch the IRK.