Re: [PATCH] Bluetooth: L2CAP: rate-limit ECHO_RSP per signaling PDU

[Michael Bommarito]

On Mon, May 18, 2026 at 5:37 PM Luiz Augusto von Dentz
<luiz.dentz@xxxxxxxxx> wrote:

Two questions on this:

> > Implementations shall be able to handle the reception of multiple
> > commands in an L2CAP packet sent over fixed channel CID 0x0001.
> > [] https://www.bluetooth.com/wp-content/uploads/Files/Specification/HTML/Core-62/out/en/host/logical-link-control-and-adaptation-protocol-specification.html#UUID-32a25a06-4aa4-c6c7-77c5-dcfe3682355d
> >
> > Perhaps we should define our Signalling MTU:
> >
> > Signaling MTU (MTUsig)
> ...

I went to add the constant in l2cap.h and noticed that our const names
don't quite align with the spec names.  Do you want me to call this
MAX_MTU to be consistent with the const names or SIG_MTU to stick to
the standard?


> So we need to reject with L2CAP_REJ_MTU_EXCEEDED.

It looks like this would be our first use of L2CAP_REJ_MTU_EXCEEDED
anywhere, which seemed suspicious.  Can you think of any other
locations offhand where we might want to check for an MTU guard?

Thanks,
Mike