[ovs-dev] [PATCH ovn] northd: By pass IPv6 Router Adv and Router Solicitation packets from ACL stages.

[Numan Siddique]

On Thu, Jun 11, 2020 at 8:13 PM Mark Michelson <mmichels at redhat.com> wrote:

> Hi Numan,
>
> I was a bit surprised to find that "nd" did not cover "nd_rs" and
> "nd_ra" packets already. Is there a reason not to expand the scope of
> "nd" to cover ICMP6 type 133 and 134?
>

The document in ovn-sb.xml says:

 ·      nd expands to icmp6.type == {135, 136} && icmp6.code == 0 && ip.ttl
== 255

So I think it was intended to be used for IPv6 Neighbor discovery packets
and not
for Router Adv/Router solicitation packets.

Thanks
Numan


> On 6/11/20 9:14 AM, numans at ovn.org wrote:
> > From: Numan Siddique <numans at ovn.org>
> >
> > We already add below logical flows to by pass IPv6 Neighbor discovery
> packets
> > from in/out ACL stage.
> >
> > table=6 (ls_in_acl          ), priority=65535, match=(nd), action=(next;)
> > table=4 (ls_out_acl         ), priority=65535, match=(nd), action=(next;)
> >
> > This patch also adds nd_rs and nd_ra to these logical flows. Without
> these
> > the IPv6 Router Adv packets generated by ovn-controller are dropped if
> > CMS has configured ACLs.
> >
> > Reported-by: Jakub Libosvar <jlibosva at redhat.com>
> > Signed-off-by: Numan Siddique <numans at ovn.org>
> > ---
> >   northd/ovn-northd.8.xml | 6 ++++++
> >   northd/ovn-northd.c     | 6 ++++--
> >   2 files changed, 10 insertions(+), 2 deletions(-)
> >
> > diff --git a/northd/ovn-northd.8.xml b/northd/ovn-northd.8.xml
> > index 7281eeecc..a7639f33a 100644
> > --- a/northd/ovn-northd.8.xml
> > +++ b/northd/ovn-northd.8.xml
> > @@ -467,6 +467,12 @@
> >           ACL re-allow this connection.
> >         </li>
> >
> > +      <li>
> > +        A priority-65535 flow that allows IPv6 Neighbor solicitation,
> > +        Neighbor discover, Router solicitation and Router advertisement
> > +        packets.
> > +      </li>
> > +
> >         <li>
> >           A priority 34000 logical flow is added for each logical switch
> datapath
> >           with the match <code>eth.dst = <var>E</var></code> to allow
> the service
> > diff --git a/northd/ovn-northd.c b/northd/ovn-northd.c
> > index 0fc62bf91..b8c9e9325 100644
> > --- a/northd/ovn-northd.c
> > +++ b/northd/ovn-northd.c
> > @@ -5389,8 +5389,10 @@ build_acls(struct ovn_datapath *od, struct hmap
> *lflows,
> >           /* Ingress and Egress ACL Table (Priority 65535).
> >            *
> >            * Not to do conntrack on ND packets. */
> > -        ovn_lflow_add(lflows, od, S_SWITCH_IN_ACL, UINT16_MAX, "nd",
> "next;");
> > -        ovn_lflow_add(lflows, od, S_SWITCH_OUT_ACL, UINT16_MAX, "nd",
> "next;");
> > +        ovn_lflow_add(lflows, od, S_SWITCH_IN_ACL, UINT16_MAX,
> > +                      "nd || nd_ra || nd_rs", "next;");
> > +        ovn_lflow_add(lflows, od, S_SWITCH_OUT_ACL, UINT16_MAX,
> > +                      "nd || nd_ra || nd_rs", "next;");
> >       }
> >
> >       /* Ingress or Egress ACL Table (Various priorities). */
> >
>
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