net/sched: act_ct: handle DNAT tuple collision

This this the counterpart of 8aa7b526dc ("openvswitch: handle DNAT
tuple collision") for act_ct. From that commit changelog:

"""
With multiple DNAT rules it's possible that after destination
translation the resulting tuples collide.

...

Netfilter handles this case by allocating a null binding for SNAT at
egress by default.  Perform the same operation in openvswitch for DNAT
if no explicit SNAT is requested by the user and allocate a null binding
for SNAT for packets in the "original" direction.
"""

Fixes: 95219afbb9 ("act_ct: support asymmetric conntrack")
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Marcelo Ricardo Leitner 2021-06-09 11:23:56 -03:00 committed by David S. Miller
parent d2e381c496
commit 13c62f5371
1 changed files with 12 additions and 7 deletions

View File

@ -904,14 +904,19 @@ static int tcf_ct_act_nat(struct sk_buff *skb,
}
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;
if (err == NF_ACCEPT && ct->status & IPS_DST_NAT) {
if (ct->status & IPS_SRC_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);
err = ct_nat_execute(skb, ct, ctinfo, range,
maniptype);
} else if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL) {
err = ct_nat_execute(skb, ct, ctinfo, NULL,
NF_NAT_MANIP_SRC);
}
}
return err;
#else