From: Johannes Berg <johannes@sipsolutions.net>
To: James Prestwood <prestwoj@gmail.com>, linux-wireless@vger.kernel.org
Subject: Re: [RFC 0/1] Allow MAC change on up interface
Date: Mon, 19 Aug 2019 12:14:15 +0200 [thread overview]
Message-ID: <645af7dad899e8eb186b3fee0f8a8a151a408557.camel@sipsolutions.net> (raw)
In-Reply-To: <20190815185702.30937-1-prestwoj@gmail.com> (sfid-20190815_205833_978900_86B1E73D)
On Thu, 2019-08-15 at 11:57 -0700, James Prestwood wrote:
> This is an example of how a devices MAC address could be changed while
> the interface is up. Currently RTNL and mac80211 both require the
> interface be down before changing the MAC.
>
> After poking around a bit I found that some drivers can actually
> change the MAC while the iface is up. Allowing user space to do this
> while the iface is up would elminate a few potential race conditions
> that arise when changing the MAC from user space.
>
> This commit does a few things:
> - Adds an EXT_FEATURE that user space can check to see if the driver
> allows this MAC changing.
> - Adds a new NL80211_ATTR for including a "random mac" to
> CMD_CONNECT. This MAC is passed down the stack and gets set to
> the net_device's address.
> - Set this wiphy extended feature in iwlwifi (just as an example)
> - Relax checks in mac80211 which check if the interface is running
> - Set IFF_LIVE_ADDR_CHANGE on net_device. Note: I know setting this
> where I did is likely not the right way to do it, but for this
> proof-of-concept it works. With guidance I can move this around
> to a proper place.
It actually seems wrong to set IFF_LIVE_ADDR_CHANGE at all, because you
don't actually support that - you only support setting it while not
connected?
johannes
next prev parent reply other threads:[~2019-08-19 10:14 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-15 18:57 [RFC 0/1] Allow MAC change on up interface James Prestwood
2019-08-15 18:57 ` [RFC 1/1] RFC: allow mac address change on up iface James Prestwood
2019-08-15 20:48 ` [RFC 0/1] Allow MAC change on up interface Jeff Johnson
2019-08-16 9:56 ` Toke Høiland-Jørgensen
2019-08-19 10:14 ` Johannes Berg [this message]
2019-08-19 15:55 ` James Prestwood
2019-08-19 20:20 ` Johannes Berg
2019-08-19 20:58 ` Denis Kenzior
2019-08-20 8:59 ` Johannes Berg
2019-08-20 15:40 ` Denis Kenzior
2019-08-20 17:53 ` Dan Williams
2019-08-20 18:21 ` Denis Kenzior
2019-08-20 18:54 ` Toke Høiland-Jørgensen
2019-08-20 19:32 ` Johannes Berg
2019-08-20 19:46 ` Denis Kenzior
2019-08-20 20:01 ` Johannes Berg
2019-08-19 21:14 ` James Prestwood
2019-08-20 6:59 ` Johannes Berg
2019-08-20 19:22 ` Denis Kenzior
2019-08-20 19:43 ` Johannes Berg
2019-08-20 19:58 ` Denis Kenzior
2019-08-20 20:15 ` Johannes Berg
2019-08-20 20:37 ` Denis Kenzior
2019-08-20 21:18 ` Dan Williams
2019-08-20 21:52 ` Denis Kenzior
2019-08-21 7:21 ` Johannes Berg
2019-08-20 19:53 ` James Prestwood
2019-08-20 20:06 ` Johannes Berg
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