Re: Flow Control and Port Mirroring Revisited

[Eric Dumazet <eric.dumazet@gmail.com>]

Le jeudi 06 janvier 2011 à 21:44 +0900, Simon Horman a écrit :

> Hi Eric !
> 
> Thanks for the advice. I had thought about the socket buffer but at some
> point it slipped my mind.
> 
> In any case the following patch seems to implement the change that I had in
> mind. However my discussions Michael Tsirkin elsewhere in this thread are
> beginning to make me think that think that perhaps this change isn't the
> best solution.
> 
> diff --git a/datapath/actions.c b/datapath/actions.c
> index 5e16143..505f13f 100644
> --- a/datapath/actions.c
> +++ b/datapath/actions.c
> @@ -384,7 +384,12 @@ static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,
>  
>  	for (a = actions, rem = actions_len; rem > 0; a = nla_next(a, &rem)) {
>  		if (prev_port != -1) {
> -			do_output(dp, skb_clone(skb, GFP_ATOMIC), prev_port);
> +			struct sk_buff *nskb = skb_clone(skb, GFP_ATOMIC);
> +			if (nskb) {
> +				if (skb->sk)
> +					skb_set_owner_w(nskb, skb->sk);
> +				do_output(dp, nskb, prev_port);
> +			}
>  			prev_port = -1;
>  		}
> 
> I got a rather nasty panic without the if (skb->sk),
> I guess some skbs don't have a socket.

Indeed, some packets are not linked to a socket.

(ARP packets for example)

Sorry, I should have mentioned it :)