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act_ct: support asymmetric conntrack

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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: b57dc7c13e ("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>
This commit is contained in:
Aaron Conole 2019-12-03 16:34:14 -05:00 committed by David S. Miller
parent 5d50aa83e2
commit 95219afbb9
1 changed files with 12 additions and 1 deletions
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13
net/sched/act_ct.c
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@ -329,6 +329,7 @@ static int tcf_ct_act_nat(struct sk_buff *skb,
bool commit) bool commit)
{ {
#if IS_ENABLED(CONFIG_NF_NAT) #if IS_ENABLED(CONFIG_NF_NAT)
int err;
enum nf_nat_manip_type maniptype; enum nf_nat_manip_type maniptype;
if (!(ct_action & TCA_CT_ACT_NAT)) 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 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 #else
return NF_ACCEPT; return NF_ACCEPT;
#endif #endif