usb: investigate if Network Buffer can be used in USB device stack and USB drivers

[jfischer-no]

Investigate if net_buf can be used in USB device stack and USB drivers.

Reason: The memory should be used more efficiently and secure. Unnecessary copying should be avoided. Support for multiple device instances should be considered.

There are many locale buffers in different places. Mostly these are only needed for temporary storage, whereby the content is often copied by the driver to another buffer again.

• ECM class tx_buf, rx_buf
• EEM class tx_buf, rx_buf
• RNDIS class, tx_buf
• RNDIS class, bulk out buffer
• CDC ACM class rx_buf, tx_buf per instance
• CDC ACM class ring-buffers? per instance
• loopback function
• MSC class

Worse is the situation with the standard, class and vendor request buffer. It is only used for the request over Control Pipe and also passed class drivers like hid and dfu. The buffer is usually not or little used during normal function. There is no verification that it is not written beyond the bounds of the buffer.

Classes already uses net_buf only:

• Bluetooth USB HCI

... will be continued ...

[finikorg]

If usb_transfer() functions could use buffers Ethernet over USB code can be easily transformed.

[jli157]

@jfischer-no Any updates for this issue?

[jfischer-no]

@jfischer-no Any updates for this issue?

It is part of new USB device controller driver API, RFC PR will be opened soon.

[carlescufi]

Fixed in the new USB stack, use CONFIG_USB_DEVICE_STACK_NEXT to enable it.