Re: [PATCH bpf v2] bpf: clear skb->tstamp in bpf_redirect when necessary

From: Alexei Starovoitov
Date: Fri Dec 13 2019 - 18:25:41 EST


On Fri, Dec 13, 2019 at 1:09 PM Eric Dumazet <eric.dumazet@xxxxxxxxx> wrote:
>
>
>
> On 12/13/19 10:08 AM, Lorenz Bauer wrote:
> > Redirecting a packet from ingress to egress by using bpf_redirect
> > breaks if the egress interface has an fq qdisc installed. This is the same
> > problem as fixed in 'commit 8203e2d844d3 ("net: clear skb->tstamp in forwarding paths")
> >
> > Clear skb->tstamp when redirecting into the egress path.
> >
> > Fixes: 80b14dee2bea ("net: Add a new socket option for a future transmit time.")
> > Fixes: fb420d5d91c1 ("tcp/fq: move back to CLOCK_MONOTONIC")
> > Signed-off-by: Lorenz Bauer <lmb@xxxxxxxxxxxxxx>
> > ---
> > net/core/filter.c | 1 +
> > 1 file changed, 1 insertion(+)
> >
> > diff --git a/net/core/filter.c b/net/core/filter.c
> > index f1e703eed3d2..d914257763b5 100644
> > --- a/net/core/filter.c
> > +++ b/net/core/filter.c
> > @@ -2055,6 +2055,7 @@ static inline int __bpf_tx_skb(struct net_device *dev, struct sk_buff *skb)
> > }
> >
> > skb->dev = dev;
> > + skb->tstamp = 0;
> >
> > dev_xmit_recursion_inc();
> > ret = dev_queue_xmit(skb);
> >
>
> Thanks !
>
> Reviewed-by: Eric Dumazet <edumazet@xxxxxxxxxx>

Applied. Thanks