How to SD assign connection handle after reconnect ?

RE: How to SD assign connection handle after reconnect ?

yuval — Tue, 15 Feb 2022 06:39:54 GMT

Haakonsh,

I'm not sure i understand your solution. If "current_handle" in the example can get "6" from the SD then in the "on_disconnect" function the "conn_handles" array will be out of bounds... Can you clarify this?

Another thing, Do we have the same issue in "multi peripheral" systems?

Thank in advance,

Yuval.

RE: How to SD assign connection handle after reconnect ?

Vyacheslav Lebets — Fri, 23 Oct 2020 12:42:13 GMT

Ok, thanks.
You have confirmed my reasoning.
I was going to do so, just wanted to clarify. Maybe SD thinks instead of me. :).

RE: How to SD assign connection handle after reconnect ?

haakonsh — Fri, 23 Oct 2020 09:49:03 GMT

[quote user=""]My question is: Is it safe to use the connection handle as an index of array, or still need to implement own control algorithm?[/quote]

Not really, precisely because of the issues you've raised. You need to handle the state when a disconnected link is re-established. You can have an array of structs:

typedef struct{
    /** Flag used to indicate available slot.*/
    bool taken;
    
    /** Connection handle.*/
    uint16_t conn_handle;
}conn_handles_t;

conn_handles_t conn_handles[NRF_SDH_BLE_CENTRAL_LINK_COUNT];

memset(conn_handles[0], '0', sizeof(conn_handles));

on_connect()
{
    for(i = 0; i < NRF_SDH_BLE_CENTRAL_LINK_COUNT; i++)
    {
        // Assing the connection handle to first available slot
        if(!conn_handles[i].taken)
        {
            conn_handles[i].taken = true;
            conn_handles[i].conn_handle = current_handle;
            
            //TODO: Save the index before exiting
            
            break;
        }
    }
}

on_disconnect()
{
    conn_handles[current_handle].taken = false;
    conn_handles[current_handle].conn_handle = BLE_CONN_HANDLE_INVALID;
}

Or you can find other ways to keep track of your handles.