From: Hannes Frederic Sowa <hannes@stressinduktion.org>
To: Yannick Koehler <yannick@koehler.name>
Cc: netdev@vger.kernel.org
Subject: Re: Unix Socket buffer attribution
Date: Wed, 23 Jan 2013 19:35:53 +0100 [thread overview]
Message-ID: <20130123183553.GA13433@order.stressinduktion.org> (raw)
In-Reply-To: <CAJ4BwwFYKYOJoP34cGqWyE_AzxMwDNqFG-XDjLB6ZdO4nQmY4w@mail.gmail.com>
On Wed, Jan 23, 2013 at 11:41:16AM -0500, Yannick Koehler wrote:
> I did some more research, I found out that netlink and
> sock_queue_err_skb does the same trick that I claim to be missing
> under the net/unix/af_unix.c. After adding the code, I got a problem
> since af_unix.c "_recvmsg()" functions assume that the skb->sk is
> holding the peer socket not the current one related to the receive
> skb. It extract the sun_path name from it. Since with UDP each
> packet may have a different peer, the only solution I found was to use
> the skb control block to hold the peer name. The problem is that this
> cb member is 48 bytes in length and sun_path is 108 bytes in size. So
> I had to increase it from 48 to 160 bytes.
>
> This obviously increase the cost of an SKB struct, so I do not really
> like this solution. But at least it seems to prove my point and now,
> with this I can have my clients working except the one mis-behaving.
> I am attaching a patch.
Yes, you cannot do that. I would try to place a refcounted pointer to the
original sk in unix_skb_params. Perhaps a refcounted unix_address will dot the
trick, too.
prev parent reply other threads:[~2013-01-23 18:35 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-22 2:01 Unix Socket buffer attribution Yannick Koehler
2013-01-23 9:59 ` Hannes Frederic Sowa
2013-01-23 16:39 ` Yannick Koehler
2013-01-23 11:42 ` Cong Wang
2013-01-23 14:26 ` Eric Dumazet
2013-01-23 16:36 ` Yannick Koehler
2013-01-23 16:56 ` Eric Dumazet
2013-01-23 17:13 ` Eric Dumazet
2013-01-23 17:36 ` Yannick Koehler
2013-01-23 16:41 ` Yannick Koehler
2013-01-23 18:35 ` Hannes Frederic Sowa [this message]
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