Received-SPF: pass (google.com: best guess record for domain of linux-wireless-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Subject: Re: cellular modem APIs - take 2
To:     Johannes Berg <johannes@sipsolutions.net>,
        Marcel Holtmann <marcel@holtmann.org>
Cc:     netdev@vger.kernel.org, linux-wireless@vger.kernel.org,
        Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>,
        Dan Williams <dcbw@redhat.com>,
        Sean Tranchetti <stranche@codeaurora.org>,
        Daniele Palmas <dnlplm@gmail.com>,
        Aleksander Morgado <aleksander@aleksander.es>,
        =?UTF-8?Q?Bj=c3=b8rn_Mork?= <bjorn@mork.no>
References: <b59be15f1d0caa4eaa4476bbd8457afc44d57089.camel@sipsolutions.net>
 <662BBC5C-D0C7-4B2C-A001-D6F490D0F36F@holtmann.org>
 <acf18b398fd63f2dfece5981ebd5057141529e6a.camel@sipsolutions.net>
From:   Denis Kenzior <denkenz@gmail.com>
Message-ID: <8b6b6174-7de4-b9a9-242b-765da647402e@gmail.com>
Date:   Wed, 29 May 2019 15:44:12 -0500
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101
 Thunderbird/52.3.0
MIME-Version: 1.0
In-Reply-To: <acf18b398fd63f2dfece5981ebd5057141529e6a.camel@sipsolutions.net>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Sender: linux-wireless-owner@vger.kernel.org
Precedence: bulk

Hi Johannes,

> 
> After all, I'm not really proposing that we put oFono or something like
> it into the kernel - far from it! I'm only proposing that we kill the
> many various ways of creating and managing the necessary netdevs (VLANs,
> sysfs, rmnet, ...) from a piece of software like oFono (or libmbim or
> whatever else).

I do like the concept of unifying this if possible.  The question is, is 
it actually possible :)  I think Dan covered most of the aspects of what 
userspace has to deal with already.  But the basic issue is that there's 
a heck of a lot of different ways of doing it.

> 
> Apart from CAIF and phonet, oFono doesn't even try to do this though,
> afaict, so I guess it relies on the default netdev created, or some out-
> of-band configuration is still needed?

Actually it can.  We can drive modems which provide only a single serial 
port and run multiplexing over that.  So we fully control the number of 
control channels created, the number of netdevs created and even 
create/destroy them on as needed basis.  And these netdevs can be PPP 
encapsulated or pure IP or whatever else.

Regards,
-Denis