Re: [PATCH 1/4] Bluetooth: Fix L2CAP PSM bind issue

[Marcel Holtmann <marcel@holtmann.org>]

Hi Syam,

> >> Problem: If we bind a particular PSM with source address as BDADDR_ANY,
> >> then we are able to bind the same PSM with adapter address(or any other
> >> address), which is incorrect.
> >
> > why is this incorrect? Explain that to me.
> >
> 
> Here there is a correction required in the commit message.
> 
> As per my understanding the a particular PSM can be binded only once
> for a single adapter address. Kindly correct me if I'm wrong here.

a PSM can be bound once per adapter address. And of course once per
BDADDR_ANY.

So you can bind PSM 23 to BDADDR_ANY and 11:22:33:44:55:66. An incoming
connection to 11:22:33:44:55:66 will arrive to that specific socket, but
an incoming to all others will be handled by the BDADDR_ANY.

The BDADDR_ANY is special. Consider it a wildcard bound with lower
priority. If overwritten with a specific address bound, that will be
considered first of course.

If we are not doing it that way, than that is a bug.

Outgoing connections should behave the same btw. If a specific address
is bound, than that will be used. If not available, then you can not
connect. If BDADDR_ANY is used, then the next available adapter will be
used.

Regards

Marcel