Marcelo Ricardo Leitner <[email protected]> writes: > On Fri, Nov 08, 2019 at 04:07:14PM -0500, Aaron Conole wrote: >> 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: b57dc7c13ea9 ("net/sched: Introduce action ct") >> >> Signed-off-by: Aaron Conole <[email protected]> >> --- >> net/sched/act_ct.c | 13 ++++++++++++- >> 1 file changed, 12 insertions(+), 1 deletion(-) >> >> diff --git a/net/sched/act_ct.c b/net/sched/act_ct.c >> index fcc46025e790..f3232a00970f 100644 >> --- a/net/sched/act_ct.c >> +++ b/net/sched/act_ct.c >> @@ -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); >> + } > > I keep thinking about this and I'm not entirely convinced that this > shouldn't be simpler. More like: > > if (DNAT) > DNAT > if (SNAT) > SNAT > > So it always does DNAT before SNAT, similarly to what iptables would > do on PRE/POSTROUTING chains.
I can rewrite the whole function, but I wanted to start with the smaller fix that worked. I also think it needs more testing then (since it's something of a rewrite of the function). I guess it's not too important - do you think it gives any readability to do it this way? If so, I can respin the patch changing it like you describe. >> + return err; >> #else >> return NF_ACCEPT; >> #endif >> -- >> 2.21.0 >> _______________________________________________ dev mailing list [email protected] https://mail.openvswitch.org/mailman/listinfo/ovs-dev
