Re: [PATCH net] net: sched: act_mirred: Reset ct info when mirror/redirect skb
From: Roi Dayan <hidden>
Date: 2021-08-09 08:35:48
On 2021-08-09 10:04 AM, Hangbin Liu wrote:
When mirror/redirect a skb to a different port, the ct info should be reset
for reclassification. Or the pkts will match unexpected rules. For example,
with following topology and commands:
-----------
|
veth0 -+-------
|
veth1 -+-------
|
------------
tc qdisc add dev veth0 clsact
# The same with "action mirred egress mirror dev veth1" or "action mirred ingress redirect dev veth1"
tc filter add dev veth0 egress chain 1 protocol ip flower ct_state +trk action mirred ingress mirror dev veth1
tc filter add dev veth0 egress chain 0 protocol ip flower ct_state -inv action ct commit action goto chain 1
tc qdisc add dev veth1 clsact
tc filter add dev veth1 ingress chain 0 protocol ip flower ct_state +trk action drop
ping <remove ip via veth0> &
tc -s filter show dev veth1 ingress
With command 'tc -s filter show', we can find the pkts were dropped on
veth1.
We can add a fixes line on the commit added ct support
Fixes: b57dc7c13ea9 ("net/sched: Introduce action ct")
quoted hunk ↗ jump to hunk
Signed-off-by: Roi Dayan <redacted> Signed-off-by: Hangbin Liu <redacted> --- net/sched/act_mirred.c | 3 +++ 1 file changed, 3 insertions(+)diff --git a/net/sched/act_mirred.c b/net/sched/act_mirred.c index 7153c67f641e..2ef4cd2c848b 100644 --- a/net/sched/act_mirred.c +++ b/net/sched/act_mirred.c@@ -273,6 +273,9 @@ static int tcf_mirred_act(struct sk_buff *skb, const struct tc_action *a, goto out; } + /* All mirred/redirected skbs should clear previous ct info */ + nf_reset_ct(skb2); + want_ingress = tcf_mirred_act_wants_ingress(m_eaction); expects_nh = want_ingress || !m_mac_header_xmit;