spp_server example question/issue (IDFGH-9207)

[bheestandLMT]

Answers checklist.

• I have read the documentation ESP-IDF Programming Guide and the issue is not addressed there.
• I have updated my IDF branch (master or release) to the latest version and checked that the issue is present there.
• I have searched the issue tracker for a similar issue and not found a similar issue.

General issue report

When running the example code for the spp_server under Nimbke BLE, I receive an error when a device is disconnected and a notification is sent.

Once a device disconnects, and I send a notification, I get error #7 for the disconnected device notification. (Other connected devices receive the notification OK)

I see an array is made to keep track of the connected devices
uint16_t connection_handle[CONFIG_BT_NIMBLE_MAX_CONNECTIONS];

and that array is populated when a device connects:
connection_handle[event->connect.conn_handle - 1] = event->connect.conn_handle;

The connection never gets deleted from the connect_handle array on disconnect.
What is the proper way to remove the particular connection_handle when a device disconnects so that error #7 is not thrown when sending notifications.

Thanks!

[IshaESP]

Hi @bheestandLMT ,
Can you tell me on which chip you are facing this issue?

After disconnecting with one device, the connection_handle array is not being updated and while sending notifications it's giving error as the connection is not present.
Can you try these two things:

1. In disconnect event, set connection_handle[event->connect.conn_handle - 1] as -1
2. Before sending notifications, add a check that if connection_handle[event->connect.conn_handle - 1] == -1 don't send the notification.

If the above doesn't work, can you please share the error logs with us?
Thank You.

[bheestandLMT]

Thanks for the reply.
I had to alter your code slightly to get it to work.
Since the code already checked if connection_handle[ ] was = 0 in a for statement before sending a notification, i made the disconnected connection_handle array = 0 instead of -1. See the for statement code that sends notification below:
for ( int i = 0; i < CONFIG_BT_NIMBLE_MAX_CONNECTIONS; i++) { if (connection_handle[i] != 0) { struct os_mbuf *txom; txom = ble_hs_mbuf_from_flat(ntf, sizeof(ntf)); rc = ble_gatts_notify_custom(connection_handle[i], ble_spp_svc_gatt_read_val_handle, txom); if ( rc == 0 ) { ESP_LOGI(tag,"Notification sent successfully"); } else { ESP_LOGI(tag,"Error in sending notification rc = %d", rc); } } }

I also had to change the in disconnect event from event->connect.conn_handle to event->disconnect.conn.conn_handle. Here is the code I ended up using:
connection_handle[event->disconnect.conn.conn_handle - 1] = 0;

that worked perfectly and still sends notifications to any other devices that are still connected.

Please feel free to close this and thank you again!