Hello
I'm trying to track lost packets in a connection by showing the sequence number of each packet received. Specifically it's about an application that sends new measurements in 3 packets each connection interval. Some measurements are divided over 2 packets so if a packet is lost, it is very important that the central application is aware of this. I think the sequence number is somewhere inside the ble_l2cap_evt_t.rx.data array of a received notification event but I'm not getting what I would expect. The code below tries to illustrate what I mean. Inside the for loop I print the first 7 bytes of the array. The rest of the data array gives the real payload (as expected):
static void on_hvx(ble_nus_c_t * p_ble_nus_c, const ble_evt_t * p_ble_evt)
{
// HVX can only occur from client sending.
if ( (p_ble_nus_c->handles.nus_rx_handle != BLE_GATT_HANDLE_INVALID)
&&(p_ble_evt->evt.gattc_evt.params.hvx.handle==p_ble_nus_c->handles.nus_rx_handle)
&& (p_ble_nus_c->evt_handler != NULL)
)
{
//After index 7 you get data payload
for (int8_t i = 0; i < 8; i++)
{
printf("%d\t",p_ble_evt->evt.l2cap_evt.params.rx.data[i]);
}
ble_nus_c_evt_t ble_nus_c_evt;
ble_nus_c_evt.evt_type = BLE_NUS_C_EVT_NUS_RX_EVT;
ble_nus_c_evt.p_data = (uint8_t *)p_ble_evt->evt.gattc_evt.params.hvx.data;
ble_nus_c_evt.data_len = p_ble_evt->evt.gattc_evt.params.hvx.len;
p_ble_nus_c->evt_handler(p_ble_nus_c, &ble_nus_c_evt);
}
}
But I see that those first 7 bytes are always the same for all packets... So I guess the sequence number is not in there. My question is, if it is in there, how should I interpret it? And if it's not (what most likely will be the case) how can I get the sequence number out of a received notification event related to a received packet (or is this not possible?) ?
Kind regards
Mathias
EDIT 1 Picture of sniffing receiving side + sniffing file
EDIT 2 Including of code files
I put together some code files with parts of my code, representing what you asked. The first two are peripheral code, the other one is central code.
This one contains the method that handles the measures made and puts them ready to send. It also contains the method of my custom service and characteristic that handles the real sending of a notification. Sending of packets with measurements.cpp
This one contains the method that handles an ACTIVE & NACTIVE, where on the end of each radio event, the measuring and setting data ready to send is started again (which is already done before the following radio event starts, this is already validated through GPIO testing). Initialising the sending of measurements each interval.cpp
This one contains the event handler where also the notifications are handled. There the printing of the notifications is showcased. Receiving notifications and printing them.cpp
EDIT 3 Including of sniff
The sniff is made using Perytons protocol analyzer. I already tried see that sometimes an err packet is sniffed (instead of a normal packet). If I check the order for the packet before and after this red packet, there should be a packet in between there so there's a packet missing there. But this could (and will be probably be) the sniffer's fault. Petter.anlb
