Subject: Re: [PATCH] tun: orphan an skb on tx

From: "Michael S. Tsirkin" <[email-masked]>
Date: Tue, 13 Apr 2010 23:43:07 +0300

On Tue, Apr 13, 2010 at 10:38:06PM +0200, Eric Dumazet wrote:
> Le mardi 13 avril 2010 à 23:25 +0300, Michael S. Tsirkin a écrit :
> > On Tue, Apr 13, 2010 at 08:31:03PM +0200, Eric Dumazet wrote:
> > > Le mardi 13 avril 2010 à 20:39 +0300, Michael S. Tsirkin a écrit :
> > > 
> > > > > When a socket with inflight tx packets is closed, we dont block the
> > > > > close, we only delay the socket freeing once all packets were delivered
> > > > > and freed.
> > > > > 
> > > > 
> > > > Which is wrong, since this is under userspace control, so you get
> > > > unkillable processes.
> > > > 
> > > 
> > > We do not get unkillable processes, at least with sockets I was thinking
> > > about (TCP/UDP ones).
> > > 
> > > Maybe tun sockets can behave the same ?
> > 
> > Looks like that's what my patch does: ip_rcv seems to call
> > skb_orphan too.
> 
> Well, I was speaking of tx side, you speak of receiving side.

Point is, both ip_rcv and my patch call skb_orphan.

> An external flood (coming from another domain) is another problem.
> 
> A sender might flood the 'network' inside our domain. How can we
> reasonably limit the sender ?
> 
> Maybe the answer is 'We can not', but it should be stated somewhere, so
> that someone can address this point later.
> 

And whatever's done should ideally work for tap to IP
and IP to IP sockets as well, not just tap to tap.

-- 
MST