[ovs-dev] [PATCH ovn] pinctrl: fix IP buffering with connection-tracking

[Lorenzo Bianconi]

On Feb 19, Dumitru Ceara wrote:
> On 2/13/20 5:49 PM, Lorenzo Bianconi wrote:
> > Whenever we need to reinject an IP packet buffered during L2 address
> > resolution we need to preserve ovs ofport in order to let ovs
> > connection tracking to properly SNAT/DNAT the packet.
> > Do not overwrite the MFF_IN_PORT in consider_port_binding routine
> > 
> > Signed-off-by: Numan Siddique <numans at ovn.org>
> > Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi at redhat.com>
> 
> Hi Lorenzo,

Hi Dumitru,

thanks for the review :)

> 
> The code looks good to me.
> 
> I couldn't find any side effects due to not resetting MFF_IN_PORT when
> entering the router pipeline but I'm wondering if it's possible to add a
> test case for the issue you're fixing.

I guess test-cases are already in system-ovn.at:

- ovn -- DNAT and SNAT on distributed router - N/S
- ovn -- DNAT and SNAT on distributed router - N/S - IPv6
- ovn -- DNAT and SNAT on distributed router - E/W
- ovn -- DNAT and SNAT on distributed router - E/W - IPv6

but they actually run a single device.

Regards,
Lorenzo

> 
> This way, if we did miss a case when the now non-zero in_port is causing
> problems in the router pipeline we at least know that zeroing it out
> will trigger the new test to fail.
> 
> Thanks,
> Dumitru
> 
> > ---
> >  controller/physical.c | 1 -
> >  controller/pinctrl.c  | 5 ++++-
> >  2 files changed, 4 insertions(+), 2 deletions(-)
> > 
> > diff --git a/controller/physical.c b/controller/physical.c
> > index a7edaddac..144aeb7bd 100644
> > --- a/controller/physical.c
> > +++ b/controller/physical.c
> > @@ -905,7 +905,6 @@ consider_port_binding(struct ovsdb_idl_index *sbrec_port_binding_by_name,
> >          for (int i = 0; i < MFF_N_LOG_REGS; i++) {
> >              put_load(0, MFF_LOG_REG0 + i, 0, 32, ofpacts_p);
> >          }
> > -        put_load(0, MFF_IN_PORT, 0, 16, ofpacts_p);
> >          put_resubmit(OFTABLE_LOG_INGRESS_PIPELINE, ofpacts_p);
> >          clone = ofpbuf_at_assert(ofpacts_p, clone_ofs, sizeof *clone);
> >          ofpacts_p->header = clone;
> > diff --git a/controller/pinctrl.c b/controller/pinctrl.c
> > index 09b0f7bf7..d06915a65 100644
> > --- a/controller/pinctrl.c
> > +++ b/controller/pinctrl.c
> > @@ -559,6 +559,7 @@ set_actions_and_enqueue_msg(struct rconn *swconn,
> >  
> >  struct buffer_info {
> >      struct ofpbuf ofpacts;
> > +    ofp_port_t ofp_port;
> >      struct dp_packet *p;
> >  };
> >  
> > @@ -629,6 +630,8 @@ buffered_push_packet(struct buffered_packets *bp,
> >      ofpbuf_init(&bi->ofpacts, 4096);
> >  
> >      reload_metadata(&bi->ofpacts, md);
> > +    bi->ofp_port = md->flow.in_port.ofp_port;
> > +
> >      struct ofpact_resubmit *resubmit = ofpact_put_RESUBMIT(&bi->ofpacts);
> >      resubmit->in_port = OFPP_CONTROLLER;
> >      resubmit->table_id = OFTABLE_REMOTE_OUTPUT;
> > @@ -663,7 +666,7 @@ buffered_send_packets(struct rconn *swconn, struct buffered_packets *bp,
> >              .ofpacts = bi->ofpacts.data,
> >              .ofpacts_len = bi->ofpacts.size,
> >          };
> > -        match_set_in_port(&po.flow_metadata, OFPP_CONTROLLER);
> > +        match_set_in_port(&po.flow_metadata, bi->ofp_port);
> >          queue_msg(swconn, ofputil_encode_packet_out(&po, proto));
> >  
> >          ofpbuf_uninit(&bi->ofpacts);
> > 
>