[PATCH net] net: sched: sch_ingress: do not report ingress filter info in egress path

[Lorenzo Bianconi]

Currently if we add a filter to the ingress qdisc (e.g matchall) the
filter data are reported even in the egress path. The issue can be
triggered with the following reproducer:

$tc qdisc add dev lo ingress
$tc filter add dev lo ingress matchall action ok
$tc filter show dev lo ingress
filter protocol all pref 49152 matchall chain 0
filter protocol all pref 49152 matchall chain 0 handle 0x1
  not_in_hw
        action order 1: gact action pass
                 random type none pass val 0
                         index 1 ref 1 bind 1

$tc filter show dev lo egress
filter protocol all pref 49152 matchall chain 0
filter protocol all pref 49152 matchall chain 0 handle 0x1
  not_in_hw
        action order 1: gact action pass
                 random type none pass val 0
                         index 1 ref 1 bind 1

Fix it reporting NULL for non-ingress filters in ingress_tcf_block
routine

Fixes: 6529eaba33f0 ("net: sched: introduce tcf block infrastructure")
Signed-off-by: Lorenzo Bianconi <lorenzo.bianc...@redhat.com>
---
 net/sched/sch_ingress.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/net/sched/sch_ingress.c b/net/sched/sch_ingress.c
index 0bac926b46c7..1825347fed3a 100644
--- a/net/sched/sch_ingress.c
+++ b/net/sched/sch_ingress.c
@@ -31,7 +31,7 @@ static struct Qdisc *ingress_leaf(struct Qdisc *sch, unsigned 
long arg)
 
 static unsigned long ingress_find(struct Qdisc *sch, u32 classid)
 {
-       return TC_H_MIN(classid) + 1;
+       return TC_H_MIN(classid);
 }
 
 static unsigned long ingress_bind_filter(struct Qdisc *sch,
@@ -53,7 +53,12 @@ static struct tcf_block *ingress_tcf_block(struct Qdisc 
*sch, unsigned long cl,
 {
        struct ingress_sched_data *q = qdisc_priv(sch);
 
-       return q->block;
+       switch (cl) {
+       case TC_H_MIN(TC_H_MIN_INGRESS):
+               return q->block;
+       default:
+               return NULL;
+       }
 }
 
 static void clsact_chain_head_change(struct tcf_proto *tp_head, void *priv)
-- 
2.20.1