Re: [PATCH v5 net 3/6] net/sched: Reserve TC_H_INGRESS (TC_H_CLSACT) for ingress (clsact) Qdiscs

Pedro Tammela
2023-05-24T15:45:20Z

On 23/05/2023 22:19, Peilin Ye wrote:
> From: Peilin Ye <peilin.ye@bytedance.com>
>
> Currently it is possible to add e.g. an HTB Qdisc under ffff:fff1
> (TC_H_INGRESS, TC_H_CLSACT):
>
> $ ip link add name ifb0 type ifb
> $ tc qdisc add dev ifb0 parent ffff:fff1 htb
> $ tc qdisc add dev ifb0 clsact
> Error: Exclusivity flag on, cannot modify.
> $ drgn
> ...
> >>> ifb0 = netdev_get_by_name(prog, "ifb0")
> >>> qdisc = ifb0.ingress_queue.qdisc_sleeping
> >>> print(qdisc.ops.id.string_().decode())
> htb
> >>> qdisc.flags.value_() # TCQ_F_INGRESS
> 2
>
> Only allow ingress and clsact Qdiscs under ffff:fff1. Return -EINVAL
> for everything else. Make TCQ_F_INGRESS a static flag of ingress and
> clsact Qdiscs.
>
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> Fixes: 1f211a1b929c ("net, sched: add clsact qdisc")
> Reviewed-by: Jamal Hadi Salim <jhs@mojatatu.com>
> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
> Signed-off-by: Peilin Ye <peilin.ye@bytedance.com>

Tested-by: Pedro Tammela <pctammela@mojatatu.com>

> ---
> change in v3, v4:
> - add in-body From: tag
>
> net/sched/sch_api.c | 7 ++++++-
> net/sched/sch_ingress.c | 4 ++--
> 2 files changed, 8 insertions(+), 3 deletions(-)
>
> diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
> index fdb8f429333d..383195955b7d 100644
> --- a/net/sched/sch_api.c
> +++ b/net/sched/sch_api.c
> @@ -1252,7 +1252,12 @@ static struct Qdisc *qdisc_create(struct net_device *dev,
> sch->parent = parent;
>
> if (handle == TC_H_INGRESS) {
> - sch->flags |= TCQ_F_INGRESS;
> + if (!(sch->flags & TCQ_F_INGRESS)) {
> + NL_SET_ERR_MSG(extack,
> + "Specified parent ID is reserved for ingress and clsact Qdiscs");
> + err = -EINVAL;
> + goto err_out3;
> + }
> handle = TC_H_MAKE(TC_H_INGRESS, 0);
> } else {
> if (handle == 0) {
> diff --git a/net/sched/sch_ingress.c b/net/sched/sch_ingress.c
> index 35963929e117..e43a45499372 100644
> --- a/net/sched/sch_ingress.c
> +++ b/net/sched/sch_ingress.c
> @@ -140,7 +140,7 @@ static struct Qdisc_ops ingress_qdisc_ops __read_mostly = {
> .cl_ops = &ingress_class_ops,
> .id = "ingress",
> .priv_size = sizeof(struct ingress_sched_data),
> - .static_flags = TCQ_F_CPUSTATS,
> + .static_flags = TCQ_F_INGRESS | TCQ_F_CPUSTATS,
> .init = ingress_init,
> .destroy = ingress_destroy,
> .dump = ingress_dump,
> @@ -281,7 +281,7 @@ static struct Qdisc_ops clsact_qdisc_ops __read_mostly = {
> .cl_ops = &clsact_class_ops,
> .id = "clsact",
> .priv_size = sizeof(struct clsact_sched_data),
> - .static_flags = TCQ_F_CPUSTATS,
> + .static_flags = TCQ_F_INGRESS | TCQ_F_CPUSTATS,
> .init = clsact_init,
> .destroy = clsact_destroy,
> .dump = ingress_dump,