From 8ca1b090e5c9a71abeea1dda8757f4ec3811f06e Mon Sep 17 00:00:00 2001 From: Marcelo Ricardo Leitner Date: Mon, 22 Mar 2021 15:13:22 -0300 Subject: [PATCH] net/sched: act_ct: clear post_ct if doing ct_clear Invalid detection works with two distinct moments: act_ct tries to find a conntrack entry and set post_ct true, indicating that that was attempted. Then, when flow dissector tries to dissect CT info and no entry is there, it knows that it was tried and no entry was found, and synthesizes/sets key->ct_state = TCA_FLOWER_KEY_CT_FLAGS_TRACKED | TCA_FLOWER_KEY_CT_FLAGS_INVALID; mimicing what OVS does. OVS has this a bit more streamlined, as it recomputes the key after trying to find a conntrack entry for it. Issue here is, when we have 'tc action ct clear', it didn't clear post_ct, causing a subsequent match on 'ct_state -trk' to fail, due to the above. The fix, thus, is to clear it. Reproducer rules: tc filter add dev enp130s0f0np0_0 ingress prio 1 chain 0 \ protocol ip flower ip_proto tcp ct_state -trk \ action ct zone 1 pipe \ action goto chain 2 tc filter add dev enp130s0f0np0_0 ingress prio 1 chain 2 \ protocol ip flower \ action ct clear pipe \ action goto chain 4 tc filter add dev enp130s0f0np0_0 ingress prio 1 chain 4 \ protocol ip flower ct_state -trk \ action mirred egress redirect dev enp130s0f1np1_0 With the fix, the 3rd rule matches, like it does with OVS kernel datapath. Fixes: 7baf2429a1a9 ("net/sched: cls_flower add CT_FLAGS_INVALID flag support") Signed-off-by: Marcelo Ricardo Leitner Reviewed-by: wenxu Signed-off-by: David S. Miller --- net/sched/act_ct.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/net/sched/act_ct.c b/net/sched/act_ct.c index f0a0aa125b00a..16e888a9601dd 100644 --- a/net/sched/act_ct.c +++ b/net/sched/act_ct.c @@ -945,13 +945,14 @@ static int tcf_ct_act(struct sk_buff *skb, const struct tc_action *a, tcf_lastuse_update(&c->tcf_tm); if (clear) { + qdisc_skb_cb(skb)->post_ct = false; ct = nf_ct_get(skb, &ctinfo); if (ct) { nf_conntrack_put(&ct->ct_general); nf_ct_set(skb, NULL, IP_CT_UNTRACKED); } - goto out; + goto out_clear; } family = tcf_ct_skb_nf_family(skb); @@ -1030,8 +1031,9 @@ out_push: skb_push_rcsum(skb, nh_ofs); out: - tcf_action_update_bstats(&c->common, skb); qdisc_skb_cb(skb)->post_ct = true; +out_clear: + tcf_action_update_bstats(&c->common, skb); if (defrag) qdisc_skb_cb(skb)->pkt_len = skb->len; return retval; -- 2.30.2