On Mon, May 28, 2018 at 04:27:46PM +0200, Toke Høiland-Jørgensen wrote:
> When CAKE is deployed on a gateway that also performs NAT (which is a
> common deployment mode), the host fairness mechanism cannot distinguish
> internal hosts from each other, and so fails to work correctly.
>
> To fix this, we add an optional NAT awareness mode, which will query the
> kernel conntrack mechanism to obtain the pre-NAT addresses for each packet
> and use that in the flow and host hashing.
>
> When the shaper is enabled and the host is already performing NAT, the cost
> of this lookup is negligible. However, in unlimited mode with no NAT being
> performed, there is a significant CPU cost at higher bandwidths. For this
> reason, the feature is turned off by default.
>
> Cc: netfilter-devel@xxxxxxxxxxxxxxx
> Signed-off-by: Toke Høiland-Jørgensen <toke@xxxxxxx>
> ---
> net/sched/sch_cake.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 46 insertions(+)
>
> diff --git a/net/sched/sch_cake.c b/net/sched/sch_cake.c
> index 68ac908470f1..fecd9caac0cc 100644
> --- a/net/sched/sch_cake.c
> +++ b/net/sched/sch_cake.c
> @@ -71,6 +71,10 @@
> #include <net/tcp.h>
> #include <net/flow_dissector.h>
>
> +#if IS_ENABLED(CONFIG_NF_CONNTRACK)
> +#include <net/netfilter/nf_conntrack_core.h>
> +#endif
> +
> #define CAKE_SET_WAYS (8)
> #define CAKE_MAX_TINS (8)
> #define CAKE_QUEUES (1024)
> @@ -516,6 +520,29 @@ static bool cobalt_should_drop(struct cobalt_vars *vars,
> return drop;
> }
>
> +static void cake_update_flowkeys(struct flow_keys *keys,
> + const struct sk_buff *skb)
> +{
> +#if IS_ENABLED(CONFIG_NF_CONNTRACK)
I would remove the ifdef, not really needed, it will simplify things.
But I leave it to you to decide, this is not I deal breaker.
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