| Message ID | 20191108210714.12426-2-aconole@redhat.com |
|---|---|
| State | Awaiting Upstream |
| Headers | show |
| Series | [ovs-dev,net,1/2] openvswitch: support asymmetric conntrack | expand |
On 2019-11-08 11:07 PM, 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 <aconole@redhat.com> > --- > 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); > + } > + return err; > #else > return NF_ACCEPT; > #endif > +paul
On 11/14/2019 4:22 PM, Roi Dayan wrote: > > On 2019-11-08 11:07 PM, 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 <aconole@redhat.com> >> --- >> 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); >> + } >> + return err; >> #else >> return NF_ACCEPT; >> #endif >> > +paul Hi Aaron, I think I understand the issue and this looks good, Can you describe the scenario to reproduce this? Thanks, Paul.
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 <aconole@redhat.com> > --- > 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. > + return err; > #else > return NF_ACCEPT; > #endif > -- > 2.21.0 >
Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> 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 <aconole@redhat.com> >> --- >> 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 >>
Paul Blakey <paulb@mellanox.com> writes: > On 11/14/2019 4:22 PM, Roi Dayan wrote: >> >> On 2019-11-08 11:07 PM, 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 <aconole@redhat.com> >>> --- >>> 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); >>> + } >>> + return err; >>> #else >>> return NF_ACCEPT; >>> #endif >>> >> +paul > > Hi Aaron, > > I think I understand the issue and this looks good, > > Can you describe the scenario to reproduce this? It reproduces with OpenShift 3.10, which makes forward direction packets between namespaces pump through a tun device that applies NAT rules to rewrite the dest. Limit the namespace number of ephemeral sockets using by editing net.ipv4.ip_local_port_range in the client namespace, and connect to the server namespace. That's the mechanism for OvS. But for TC I guess there wouldn't be anything convenient avaiable. I'll try to script up something that doesn't use openshift. > > Thanks, > > Paul.
On Mon, Nov 18, 2019 at 04:21:39PM -0500, Aaron Conole wrote: > Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> 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 <aconole@redhat.com> > >> --- > >> 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. I didn't mean a rewrite, but just to never handle SNAT before DNAT. So the fix here would be like: - return ct_nat_execute(skb, ct, ctinfo, range, maniptype); + err = ct_nat_execute(skb, ct, ctinfo, range, maniptype); + if (err == NF_ACCEPT && maniptype == NF_NAT_MANIP_DST && + ct->status & IPS_SRC_NAT && ct->status & IPS_DST_NAT) { + maniptype = NF_NAT_MANIP_SRC; + err = ct_nat_execute(skb, ct, ctinfo, range, maniptype); + } + return err; > >> + return err; > >> #else > >> return NF_ACCEPT; > >> #endif > >> -- > >> 2.21.0 > >> >
Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> writes: > On Mon, Nov 18, 2019 at 04:21:39PM -0500, Aaron Conole wrote: >> Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> 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 <aconole@redhat.com> >> >> --- >> >> 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. > > I didn't mean a rewrite, but just to never handle SNAT before DNAT. So > the fix here would be like: > > - return ct_nat_execute(skb, ct, ctinfo, range, maniptype); > + err = ct_nat_execute(skb, ct, ctinfo, range, maniptype); > + if (err == NF_ACCEPT && maniptype == NF_NAT_MANIP_DST && > + ct->status & IPS_SRC_NAT && ct->status & IPS_DST_NAT) { > + maniptype = NF_NAT_MANIP_SRC; > + err = ct_nat_execute(skb, ct, ctinfo, range, maniptype); > + } > + return err; But the maniptype of the first call could be NAT_MANIP_SRC. In fact, that's what I see if the packet is reply direction && !related. So, we need the block to invert the manipulation type. Otherwise, we miss the DNAT manipulation. So I don't think I can use that block. >> >> + return err; >> >> #else >> >> return NF_ACCEPT; >> >> #endif >> >> -- >> >> 2.21.0 >> >> >>
On Fri, Nov 22, 2019 at 03:39:16PM -0500, Aaron Conole wrote: > Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> writes: > > > On Mon, Nov 18, 2019 at 04:21:39PM -0500, Aaron Conole wrote: > >> Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> 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 <aconole@redhat.com> > >> >> --- > >> >> 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. > > > > I didn't mean a rewrite, but just to never handle SNAT before DNAT. So > > the fix here would be like: > > > > - return ct_nat_execute(skb, ct, ctinfo, range, maniptype); > > + err = ct_nat_execute(skb, ct, ctinfo, range, maniptype); > > + if (err == NF_ACCEPT && maniptype == NF_NAT_MANIP_DST && > > + ct->status & IPS_SRC_NAT && ct->status & IPS_DST_NAT) { > > + maniptype = NF_NAT_MANIP_SRC; > > + err = ct_nat_execute(skb, ct, ctinfo, range, maniptype); > > + } > > + return err; > > But the maniptype of the first call could be NAT_MANIP_SRC. In fact, > that's what I see if the packet is reply direction && !related. Interesting, ok. > > So, we need the block to invert the manipulation type. Otherwise, we > miss the DNAT manipulation. > > So I don't think I can use that block. Thanks for digging on it. Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> > > >> >> + return err; > >> >> #else > >> >> return NF_ACCEPT; > >> >> #endif > >> >> -- > >> >> 2.21.0 > >> >> > >> >
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); + } + return err; #else return NF_ACCEPT; #endif
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 <aconole@redhat.com> --- net/sched/act_ct.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-)