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From: David Miller <davem@davemloft.net>
To: hch@lst.de
Cc: kuba@kernel.org, kuznet@ms2.inr.ac.ru, yoshfuji@linux-ipv6.org,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 4/4] ipv6: symbol_get to access a sit symbol
Date: Sat, 16 May 2020 13:55:48 -0700 (PDT)	[thread overview]
Message-ID: <20200516.135548.2079608042651975047.davem@davemloft.net> (raw)
In-Reply-To: <20200515063324.GA31377@lst.de>

From: Christoph Hellwig <hch@lst.de>
Date: Fri, 15 May 2020 08:33:24 +0200

> My initial plan was to add a ->tunnel_ctl method to the net_device_ops,
> and lift the copy_{to,from}_user for SIOCADDTUNNEL, SIOCCHGTUNNEL,
> SIOCDELTUNNEL and maybe SIOCGETTUNNEL to net/socket.c.  But that turned
> out to have two problems:
> 
>  - first these ioctls names use SIOCDEVPRIVATE range, that can also
>    be implemented by other drivers
>  - the ip_tunnel_parm struture is only used by the ipv4 tunneling
>    drivers (including sit), the "real" ipv6 tunnels use a
>    ip6_tnl_parm or ip6_tnl_parm structure instead

Yes, this is the core of the problem, the user provided data's type
is unknown until we are very deep in the call chains.

I wonder if there is some clever way to propagate this size value
"up"?

  reply	other threads:[~2020-05-16 20:55 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-14 14:50 use symbol_get to create the magic ipv4/ipv6 tunnels Christoph Hellwig
2020-05-14 14:50 ` [PATCH 1/4] ipv4: streamline ipmr_new_tunnel Christoph Hellwig
2020-05-14 14:50 ` [PATCH 2/4] ipv4: consolidate the VIFF_TUNNEL handling in ipmr_new_tunnel Christoph Hellwig
2020-05-14 14:51 ` [PATCH 3/4] ipv4: use symbol_get to access ipip symbols Christoph Hellwig
2020-05-14 14:51 ` [PATCH 4/4] ipv6: symbol_get to access a sit symbol Christoph Hellwig
2020-05-15  0:53   ` David Miller
2020-05-15  6:33     ` Christoph Hellwig
2020-05-16 20:55       ` David Miller [this message]
2020-05-18  6:30         ` Christoph Hellwig
2020-05-19  0:36           ` David Miller

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