Commit 95219afb authored Dec 03, 2019 by Aaron Conole Committed by David S. Miller Dec 04, 2019

act_ct: support asymmetric conntrack



The act_ct TC module shares a common conntrack and NAT infrastructure
exposed via netfilter.  It's possible that a packet needs both SNAT and
DNAT manipulation, due to e.g. tuple collision.  Netfilter can support
this because it runs through the NAT table twice - once on ingress and
again after egress.  The act_ct action doesn't have such capability.

Like netfilter hook infrastructure, we should run through NAT twice to
keep the symmetry.

Fixes: b57dc7c1 ("net/sched: Introduce action ct")
Signed-off-by: Aaron Conole <aconole@redhat.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 5d50aa83

net/sched/act_ct.c

+12 −1

Original line number	Diff line number	Diff line
		@@ -329,6 +329,7 @@ static int tcf_ct_act_nat(struct sk_buff *skb,
		bool commit)
		{
		#if IS_ENABLED(CONFIG_NF_NAT)
		int err;
		enum nf_nat_manip_type maniptype;

		if (!(ct_action & TCA_CT_ACT_NAT))
		@@ -359,7 +360,17 @@ static int tcf_ct_act_nat(struct sk_buff *skb,
		return NF_ACCEPT;
		}

		return ct_nat_execute(skb, ct, ctinfo, range, maniptype);
		err = ct_nat_execute(skb, ct, ctinfo, range, maniptype);
		if (err == NF_ACCEPT &&
		ct->status & IPS_SRC_NAT && ct->status & IPS_DST_NAT) {
		if (maniptype == NF_NAT_MANIP_SRC)
		maniptype = NF_NAT_MANIP_DST;
		else
		maniptype = NF_NAT_MANIP_SRC;

		err = ct_nat_execute(skb, ct, ctinfo, range, maniptype);
		}
		return err;
		#else
		return NF_ACCEPT;
		#endif

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