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From:   Krishna Chaitanya <chaitanya.mgit@gmail.com>
Date:   Mon, 7 Sep 2020 21:52:46 +0530
Message-ID: <CABPxzYLAYaXDfEewA5XR+y2Z0N1yLbEQwQM4FNytamHeZt3ySg@mail.gmail.com>
Subject: Re: alternatives to screenscraping iw?
To:     Johannes Berg <johannes@sipsolutions.net>
Cc:     Paul Cercueil <paul@crapouillou.net>,
        linux-wireless <linux-wireless@vger.kernel.org>, od@zcrc.me
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On Mon, Sep 7, 2020 at 6:29 PM Johannes Berg <johannes@sipsolutions.net> wrote:
>
> Hi,
>
> > We're trying to move away from ifconfig/iwconfig and switch to use
> > ip/iw on our embedded systems. It works good, but we can't really adapt
> > our current tools (mostly Python wrappers). iw -h specially says not to
> > screenscrape, but we don't really have an alternative, do we?
>
> Yeah, we _have_ changed the output format sometimes ... I suppose the
> only reason iwconfig hasn't is that it's not been changed in 15 years or
> so ;-)
>
> There is a pynl80211 library, but it's not complete and maintained. If
> you only need some bits though it might be worthwhile to just do that
> internally. Python has supported netlink sockets for some time, IIRC.

FYI, We have open-sourced our internal library which takes care of abstracting
Netlink attributes, just need to define commands and event messages in JSON,
https://github.com/bluwireless/py-genl. The initial port of all
messages might be an
effort but extending it would be easy.
>
> > Would it be possible to split iw into a shared library + binary? Then
> > it'd be at least possible to create wrappers. Another idea would be to
> > have a mode for iw to output json, like 'ip' does.
>
> I actually played with this at some point, but then wanted to sort of
> use json internally so it's not maintained separately and we go through
> that ... but the message structure and our intermediate printing makes
> that actually quite difficult.
>
> johannes