Reference to implement BLE-Mesh Large object (BLOB) transfer

[Ubaid_M]

Hi,

I need to transfer BLOB object upto 350kb through BLE-Mesh.

I saw the breakup of nCS that zephyr implements Mesh protocol layers, and nordic stack implements mesh application layer.

But i couldn't find how I could implement large object transfer via mesh.

Kindly suggest how to implement BLOB transfer & also suggest a sample nCS code to do the same.

Thanks,

Ubaid

[Ubaid_M]

Hello Elfving,

Elfving said:

I will have to get back to you on this next week.

Kindly suggest on handlers for Client TX of 100 bytes & server RX of 100 bytes.

Please suggest as per the pseudo-code below:
Server RX:

#In prj.conf
CONFIG_BT_MESH_RX_SEG_MAX=20

//OPcode defn
#define BT_MESH_RX_100_OP_MESSAGE BT_MESH_MODEL_OP_3( 0x0A , BT_MESH_VENDOR_COMPANY_ID )

#define BT_MESH_PAYLOAD_GET_LEN 100
static char centLoad[100]= {0};
const struct bt_mesh_model_op _bt_mesh_vendor_srv_op[] = {
	{BT_MESH_RX_100_OP_MESSAGE,
	 BT_MESH_LEN_EXACT( BT_MESH_PAYLOAD_GET_LEN ),
	 handle_rx100B},
	 	BT_MESH_MODEL_OP_END,
};


//100bytes rx handler
static int handle_rx100B( struct bt_mesh_model* model, struct bt_mesh_msg_ctx* ctx, struct net_buf_simple* buf )
{
    struct bt_mesh_vendor_srv* srv = model->user_data;
    centLoad = net_buf_simple_pull_mem( buf, buf->len ); //buf->len is initialized to 100 from the opcode len definition right..? //
    return ( 0 );
}

Kindly suggest on this server pseudo code
And please help me with client handler TX 100 bytes code for this server.

Thanks,

Ubaid

[Elfving]

Hello Ubaid,

I haven't had the time to test this, but it looks good. 

For transmitting, if you are using the chat example as a starting point, you could:

- Edit the shell commands in SHELL_STATIC_SUBCMD_SET_CREATE to create one for starting your transfer.

- Make a shell command function similar to cmd_message, that also split your file into chunks of a 100 Bytes.

- Make a version of bt_mesh_chat_cli_message_send that uses your own opcodes to send the message.

Regards,

Elfving