From: Adhemerval Zanella <adhemerval.zanella@linaro.org>
To: Florian Weimer <fw@deneb.enyo.de>
Cc: libc-alpha@sourceware.org
Subject: Re: [PATCH] Linux: Implement opensock using Netlink sockets
Date: Mon, 18 Jun 2018 17:17:00 -0000 [thread overview]
Message-ID: <ee5a4c2d-4ccd-21ee-a915-0900b5cae764@linaro.org> (raw)
In-Reply-To: <87a7rsuim7.fsf@mid.deneb.enyo.de>
On 18/06/2018 14:09, Florian Weimer wrote:
> * Adhemerval Zanella:
>
>>> Ahh, it's been fixed since then. Netlink sockets were one of the
>>> few which did not perform ENOIOCTLCMD fallback. This was changed in
>>> kernel 4.6:
>>>
>>> commit 025c68186e07afaededa84143f1a22f273cd3f67
>>> Author: David Decotigny <decot@googlers.com>
>>> Date:Â Â Mon Mar 21 10:15:35 2016 -0700
>>>
>>> Â Â Â netlink: add support for NIC driver ioctls
>>>
>>> Â Â Â By returning -ENOIOCTLCMD, sock_do_ioctl() falls back to calling
>>> Â Â Â dev_ioctl(), which provides support for NIC driver ioctls, which
>>> Â Â Â includes ethtool support. This is similar to the way ioctls are
>>> Â Â Â handled in udp.c or tcp.c.
>>>
>>> Â Â Â This removes the requirement that ethtool for example be tied to the
>>> Â Â Â support of a specific L3 protocol (ethtool uses an AF_INET socket
>>> Â Â Â today).
>>>
>>> It's unfortunate that it took that long to make this change.
>>>
>>> Thanks,
>>> Florian
>>
>> Indeed, so I think we will need the fallback options (maybe we can restrict
>> to some options).
>
> The real question is whether it is important to avoid module loading.
> If we could just try
>
> AF_NETLINK
> AF_UNIX
> AF_INET
> AF_INET6
>
> in this order, irrespective of the module load status, the code would
> already be much, much simpler.
>
I think it should cover the expected kernel support (it would be unusual to
use the getifaddr functions with a kernel without tcpip support).
The issues is we will need to ensure the returned socket works with
SIOCGIFNAME (maybe by issuing a ioctl to make it sure).
next prev parent reply other threads:[~2018-06-18 17:17 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-18 10:50 Florian Weimer
2018-06-18 13:57 ` Adhemerval Zanella
2018-06-18 14:25 ` Florian Weimer
2018-06-18 17:09 ` Adhemerval Zanella
2018-06-18 17:11 ` Florian Weimer
2018-06-18 17:17 ` Adhemerval Zanella [this message]
2018-06-18 17:28 ` Florian Weimer
2018-06-18 16:47 ` Ben Hutchings
2018-06-18 17:13 ` Florian Weimer
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