On Tue, Aug 3, 2021 at 3:29 PM Han Zhou <[email protected]> wrote:
>
> On Tue, Jul 27, 2021 at 10:06 AM Lorenzo Bianconi <
> [email protected]> wrote:
> >
> > Introduce check_pkt_larger action for ingress traffic
> > entering the cluster from a distributed gw router port
> > or from a gw router. This patch enables pMTU discovery
> > for ingress traffic.
> >
> > Signed-off-by: Lorenzo Bianconi <[email protected]>
>
> Thanks for the patch. I hit a problem while rebasing on top of this patch.
> It is committed as:
> With the current master (already has this patch committed), the DDlog test
> case fails (100% failure when I run it individually, but sometimes passes
> when I run in parallel with other cases):
> router - check packet length - icmp defrag -- ovn-northd-ddlog --
> dp-groups=yes
>
> Reverting the commit (1c9e46ab5 northd: add check_pkt_larger lflows for
> ingress traffic) makes test pass. I haven't debugged why this happened.
>
> And I also have a question on the patch. Please see my comment below.
>
> > diff --git a/northd/ovn_northd.dl b/northd/ovn_northd.dl
> > index d1f7dbbed..838f72824 100644
> > --- a/northd/ovn_northd.dl
> > +++ b/northd/ovn_northd.dl
> > @@ -4728,7 +4728,12 @@ for (&RouterPort(.lrp = lrp,
> >       * This will save us from having to match on inport further down in
> >       * the pipeline.
> >       */
> > -    var actions = "${rEG_INPORT_ETH_ADDR()} = ${lrp_networks.ea}; next;"
> in {
> > +    var gw_mtu = lrp.options.get_int_def("gateway_mtu", 0) in
> > +    var mtu = gw_mtu + vLAN_ETH_HEADER_LEN() in
> > +    var actions = "${rEG_INPORT_ETH_ADDR()} = ${lrp_networks.ea}; " ++
> > +    if (gw_mtu > 0) {
> > +        "${rEGBIT_PKT_LARGER()} = check_pkt_larger(${mtu}); next;"
> > +    } else { "next;" } in {
> >          Flow(.logical_datapath = router._uuid,
> >               .stage            = s_ROUTER_IN_ADMISSION(),
> >               .priority         = 50,
> > @@ -7558,11 +7563,12 @@ Flow(.logical_datapath = lr_uuid,
> >      var mtu = gw_mtu + vLAN_ETH_HEADER_LEN().
> >  MeteredFlow(.logical_datapath = lr_uuid,
> >              .stage            = s_ROUTER_IN_LARGER_PKTS(),
> > -            .priority         = 50,
> > -            .__match          = "inport == ${rp.json_name} && outport ==
> ${l3dgw_port_json_name} && "
> > -                                "ip4 && ${rEGBIT_PKT_LARGER()}",
> > +            .priority         = 150,
> > +            .__match          = "inport == ${rp.json_name} && ip4 && "
> > +                                "${rEGBIT_PKT_LARGER()} &&
> ${rEGBIT_EGRESS_LOOPBACK()} == 0",
> >              .actions          = "icmp4_error {"
> >                                  "${rEGBIT_EGRESS_LOOPBACK()} = 1; "
> > +                                "${rEGBIT_PKT_LARGER()} = 0; "
> >                                  "eth.dst = ${rp.networks.ea}; "
> >                                  "ip4.dst = ip4.src; "
> >                                  "ip4.src = ${first_ipv4.addr}; "
> > @@ -7585,13 +7591,46 @@ MeteredFlow(.logical_datapath = lr_uuid,
> >      rp in &RouterPort(.router = r),
> >      rp.lrp != l3dgw_port,
> >      Some{var first_ipv4} = rp.networks.ipv4_addrs.nth(0).
> > +
> > +MeteredFlow(.logical_datapath = lr_uuid,
> > +            .stage            = s_ROUTER_IN_IP_INPUT(),
> > +            .priority         = 150,
> > +            .__match          = "inport == ${rp.json_name} && ip4 && "
> > +                                "${rEGBIT_PKT_LARGER()} &&
> ${rEGBIT_EGRESS_LOOPBACK()} == 0",
> > +            .actions          = "icmp4_error {"
> > +                                "${rEGBIT_EGRESS_LOOPBACK()} = 1; "
> > +                                "${rEGBIT_PKT_LARGER()} = 0; "
> > +                                "eth.dst = ${rp.networks.ea}; "
> > +                                "ip4.dst = ip4.src; "
> > +                                "ip4.src = ${first_ipv4.addr}; "
> > +                                "ip.ttl = 255; "
> > +                                "icmp4.type = 3; /* Destination
> Unreachable. */ "
> > +                                "icmp4.code = 4; /* Frag Needed and DF
> was Set. */ "
> > +                                /* Set icmp4.frag_mtu to gw_mtu */
> > +                                "icmp4.frag_mtu = ${gw_mtu}; "
> > +                                "next(pipeline=ingress, table=0); "
> > +                                "};",
> > +            .tags             = map_empty(),
> > +            .controller_meter = r.copp.get(cOPP_ICMP4_ERR()),
> > +            .external_ids     = stage_hint(rp.lrp._uuid)) :-
> > +    r in &Router(._uuid = lr_uuid),
> > +    Some{var l3dgw_port} = r.l3dgw_port,
> > +    var l3dgw_port_json_name = json_string_escape(l3dgw_port.name),
> > +    r.redirect_port_name != "",
> > +    var gw_mtu = l3dgw_port.options.get_int_def("gateway_mtu", 0),
> > +    gw_mtu > 0,
> > +    rp in &RouterPort(.router = r),
> > +    rp.lrp == l3dgw_port,
> > +    Some{var first_ipv4} = rp.networks.ipv4_addrs.nth(0).
> > +
>
> This flow is exactly the same as the one immediately above it, except that
> "rp.lrp == l3dgw_port" instead of "rp.lrp != l3dgw_port". Does it mean
> adding the flow for all LRPs, whether it is l3dgw_port or not? If so, why
> not combine the code just by removing the "rp.lrp == l3dgw_port" or "rp.lrp
> != l3dgw_port" check? Did I misunderstand something? Same for the ipv6 flow
> below.

I added the ddlog part of the code.  Let me check and come back.

Thanks
Numan

>
> Thanks,
> Han
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