[ovs-dev] [PATCH ovn] ovn-northd: Increase ECMP route priority with 400.

[Lorenzo Bianconi]

> On Thu, May 14, 2020 at 1:12 AM Dumitru Ceara <dceara at redhat.com> wrote:
> >
> > On 5/13/20 11:51 PM, Han Zhou wrote:
> > > In commit c0bf32d the priorities of the regular routes were increased by
> > > 400, but ECMP routes were not updated. This patch fixes it. Since
> > > for ECMP routes the outport is unknown (there can be many different
> > > outports) the condition check of whether the outport is distributed
> > > gateway port is skipped.
> > >
> > > Fixes: c0bf32d ("Manage ARP process locally in a DVR scenario")
> > > Cc: Lorenzo Bianconi <lorenzo.bianconi at redhat.com>
> > > Signed-off-by: Han Zhou <hzhou at ovn.org>

[...]

> So I wonder if we should change the solution of the commit c0bf32d, instead
> of just increasing the ECMP routes priority only. I don't completely
> understand the problem that commit was trying to solve. Is there an example
> that describes the scenario in more detail and the reason why the route
> priorities have to be different?

Hi Han,

this morning Dumitru and me worked trying to find a solution for this issue.
We though to restore the original configuration in table 9
and add a new table used only to take care of FIP/DVR traffic.
Does it work for you?
I sent a RFC with the basic implementation. I tested it and it works fine
regarding to FIP traffic. I will work on unitest waiting for feedbacks.

Regards,
Lorenzo

> 
> >
> > > ---
> > >  northd/ovn-northd.8.xml |  3 ++-
> > >  northd/ovn-northd.c     | 22 ++++++++++++----------
> > >  2 files changed, 14 insertions(+), 11 deletions(-)
> > >
> > > diff --git a/northd/ovn-northd.8.xml b/northd/ovn-northd.8.xml
> > > index 8f224b0..b0475d0 100644
> > > --- a/northd/ovn-northd.8.xml
> > > +++ b/northd/ovn-northd.8.xml
> > > @@ -2601,7 +2601,8 @@ next;
> > >            ids <var>MID1</var>, <var>MID2</var>, ..., a logical flow
> with match
> > >            in CIDR notation <code>ip4.dst ==
> <var>N</var>/<var>M</var></code>,
> > >            or <code>ip6.dst == <var>N</var>/<var>M</var></code>, whose
> priority
> > > -          is the integer value of <var>M</var>, has the following
> actions:
> > > +          is <code>400</code> + the integer value of <var>M</var>, has
> the
> > > +          following actions:
> > >          </p>
> > >
> > >          <pre>
> > > diff --git a/northd/ovn-northd.c b/northd/ovn-northd.c
> > > index b25152d..c02e305 100644
> > > --- a/northd/ovn-northd.c
> > > +++ b/northd/ovn-northd.c
> > > @@ -7337,7 +7337,8 @@ build_route_prefix_s(const struct v46_ip *prefix,
> unsigned int plen)
> > >  }
> > >
> > >  static void
> > > -build_route_match(const struct ovn_port *op_inport, const char
> *network_s,
> > > +build_route_match(const struct ovn_port *op_inport,
> > > +                  const struct ovn_port *op_outport, const char
> *network_s,
> > >                    int plen, bool is_src_route, bool is_ipv4, struct ds
> *match,
> > >                    uint16_t *priority)
> > >  {
> > > @@ -7351,6 +7352,13 @@ build_route_match(const struct ovn_port
> *op_inport, const char *network_s,
> > >          dir = "dst";
> > >          *priority = (plen * 2) + 1;
> > >      }
> > > +    /* traffic for internal IPs of logical switch ports must be sent to
> > > +     * the gw controller through the overlay tunnels
> > > +     */
> > > +    if (!op_outport ||
> > > +        (op_outport->nbrp && !op_outport->nbrp->n_gateway_chassis)) {
> > > +        priority += DROUTE_PRIO;
> > > +    }
> > >
> > >      if (op_inport) {
> > >          ds_put_format(match, "inport == %s && ", op_inport->json_key);
> > > @@ -7434,8 +7442,8 @@ build_ecmp_route_flow(struct hmap *lflows, struct
> ovn_datapath *od,
> > >      uint16_t priority;
> > >
> > >      char *prefix_s = build_route_prefix_s(&eg->prefix, eg->plen);
> > > -    build_route_match(NULL, prefix_s, eg->plen, eg->is_src_route,
> is_ipv4,
> > > -                      &match, &priority);
> > > +    build_route_match(NULL, NULL, prefix_s, eg->plen, eg->is_src_route,
> > > +                      is_ipv4, &match, &priority);
> > >      free(prefix_s);
> > >
> > >      struct ds actions = DS_EMPTY_INITIALIZER;
> > > @@ -7548,14 +7556,8 @@ add_route(struct hmap *lflows, const struct
> ovn_port *op,
> > >              op_inport = op;
> > >          }
> > >      }
> > > -    build_route_match(op_inport, network_s, plen, is_src_route,
> is_ipv4,
> > > +    build_route_match(op_inport, op, network_s, plen, is_src_route,
> is_ipv4,
> > >                        &match, &priority);
> > > -    /* traffic for internal IPs of logical switch ports must be sent to
> > > -     * the gw controller through the overlay tunnels
> > > -     */
> > > -    if (op->nbrp && !op->nbrp->n_gateway_chassis) {
> > > -        priority += DROUTE_PRIO;
> > > -    }
> > >
> > >      struct ds actions = DS_EMPTY_INITIALIZER;
> > >      ds_put_format(&actions, "ip.ttl--; "REG_ECMP_GROUP_ID" = 0; %sreg0
> = ",
> > >
> >