On Thu, Aug 6, 2020 at 11:07 AM Numan Siddique <[email protected]> wrote:
>
> On Wed, Aug 5, 2020 at 12:36 PM Han Zhou <[email protected]> wrote:
> >
> > Support a new logical router option "always_learn_from_arp_request"
that controls
> > behavior when handling ARP requests or IPv4 ND-NS packets.
> >
> > "true" - Always learn the MAC/IP binding and add a new MAC_Binding entry
> > (default behavior)
> >
> > "false" - If there is a MAC_binding for that IP and the MAC is
different, or,
> > if TPA of ARP request belongs to any router port on this router, then
> > update/add that MAC/IP binding. Otherwise, don't update/add entries.
> >
> > Reported-by: Girish Moodalbail <[email protected]>
> > Reported-at:
https://mail.openvswitch.org/pipermail/ovs-discuss/2020-May/049995.html
> > Signed-off-by: Han Zhou <[email protected]>
>
> Hi Han,
>
> I have few small nits. Please see below. With those addressed
>
> Acked-by: Numan Siddique <[email protected]> for all the 3 patches in the
series.
>
>
> > ---
> >  northd/ovn-northd.8.xml | 109
++++++++++++++++++++++++++++++++++++++++--------
> >  northd/ovn-northd.c     |  96
+++++++++++++++++++++++++++++++++++-------
> >  ovn-nb.xml              |  27 ++++++++++++
> >  tests/ovn.at            |  18 ++++++++
> >  4 files changed, 217 insertions(+), 33 deletions(-)
> >
> > diff --git a/northd/ovn-northd.8.xml b/northd/ovn-northd.8.xml
> > index 508123e..b08293f 100644
> > --- a/northd/ovn-northd.8.xml
> > +++ b/northd/ovn-northd.8.xml
> > @@ -1537,58 +1537,126 @@ output;
> >          <p>
> >            For each router port <var>P</var> that owns IP address
<var>A</var>,
> >            which belongs to subnet <var>S</var> with prefix length
<var>L</var>,
> > -          a priority-100 flow is added which matches
> > -          <code>inport == <var>P</var> &amp;&amp;
> > -          arp.spa == <var>S</var>/<var>L</var> &amp;&amp; arp.op ==
1</code>
> > -          (ARP request) with the
> > -          following actions:
> > +          if the option <code>always_learn_from_arp_request</code> is
> > +          <code>true</code> for this router, a priority-100 flow is
added which
> > +          matches <code>inport == <var>P</var> &amp;&amp; arp.spa ==
> > +          <var>S</var>/<var>L</var> &amp;&amp; arp.op == 1</code> (ARP
request)
> > +          with the following actions:
> > +        </p>
> > +
> > +        <pre>
> > +reg9[2] = lookup_arp(inport, arp.spa, arp.sha);
> > +next;
> > +        </pre>
> > +
> > +        <p>
> > +          If the option <code>always_learn_from_arp_request</code> is
> > +          <code>false</code>, the following two flows are added.
> > +        </p>
> > +
> > +        <p>
> > +          A priority-110 flow is added which matches <code>inport ==
> > +          <var>P</var> &amp;&amp; arp.spa == <var>S</var>/<var>L</var>
> > +          &amp;&amp; arp.tpa == <var>A</var> &amp;&amp; arp.op ==
1</code>
> > +          (ARP request) with the following actions:
> >          </p>
> >
> >          <pre>
> >  reg9[2] = lookup_arp(inport, arp.spa, arp.sha);
> > +reg9[3] = 1;
> > +next;
> > +        </pre>
> > +
> > +        <p>
> > +          A priority-100 flow is added which matches <code>inport ==
> > +          <var>P</var> &amp;&amp; arp.spa == <var>S</var>/<var>L</var>
> > +          &amp;&amp; arp.op == 1</code> (ARP request) with the
following
> > +          actions:
> > +        </p>
> > +
> > +        <pre>
> > +reg9[2] = lookup_arp(inport, arp.spa, arp.sha);
> > +reg9[3] = lookup_arp_ip(inport, arp.spa);
> >  next;
> >          </pre>
> >
> >          <p>
> >            If the logical router port <var>P</var> is a distributed
gateway
> >            router port, additional match
> > -          <code>is_chassis_resident(cr-<var>P</var>)</code> is added
so that
> > -          the resident gateway chassis handles the neighbor lookup.
> > +          <code>is_chassis_resident(cr-<var>P</var>)</code> is added
for all
> > +          these flows.
> >          </p>
> >        </li>
> >
> >        <li>
> >          <p>
> >            A priority-100 flow which matches on ARP reply packets and
applies
> > -          the actions:
> > +          the actions if the option
<code>always_learn_from_arp_request</code>
> > +          is <code>true</code>:
> >          </p>
> >
> >          <pre>
> >  reg9[2] = lookup_arp(inport, arp.spa, arp.sha);
> >  next;
> >          </pre>
> > +
> > +        <p>
> > +          If the option <code>always_learn_from_arp_request</code>
> > +          is <code>false</code>, the above actions will be:
> > +        </p>
> > +
> > +        <pre>
> > +reg9[2] = lookup_arp(inport, arp.spa, arp.sha);
> > +reg9[3] = 1;
> > +next;
> > +        </pre>
> > +
> >        </li>
> >
> >        <li>
> >          <p>
> >            A priority-100 flow which matches on IPv6 Neighbor Discovery
> > -          advertisement packet and applies the actions:
> > +          advertisement packet and applies the actions if the option
> > +          <code>always_learn_from_arp_request</code> is
<code>true</code>:
> >          </p>
> >
> >          <pre>
> >  reg9[2] = lookup_nd(inport, nd.target, nd.tll);
> >  next;
> >          </pre>
> > +
> > +        <p>
> > +          If the option <code>always_learn_from_arp_request</code>
> > +          is <code>false</code>, the above actions will be:
> > +        </p>
> > +
> > +        <pre>
> > +reg9[2] = lookup_nd(inport, nd.target, nd.tll);
> > +reg9[3] = 1;
> > +next;
> > +        </pre>
> >        </li>
> >
> >        <li>
> >          <p>
> >            A priority-100 flow which matches on IPv6 Neighbor Discovery
> > -          solicitation packet and applies the actions:
> > +          solicitation packet and applies the actions if the option
> > +          <code>always_learn_from_arp_request</code> is
<code>true</code>:
> > +        </p>
> > +
> > +        <pre>
> > +reg9[2] = lookup_nd(inport, ip6.src, nd.sll);
> > +next;
> > +        </pre>
> > +
> > +        <p>
> > +          If the option <code>always_learn_from_arp_request</code>
> > +          is <code>false</code>, the above actions will be:
> >          </p>
> >
> >          <pre>
> >  reg9[2] = lookup_nd(inport, ip6.src, nd.sll);
> > +reg9[3] = lookup_nd_ip(inport, ip6.src);
> >  next;
> >          </pre>
> >        </li>
> > @@ -1604,21 +1672,28 @@ next;
> >
> >      <p>
> >        This table adds flows to learn the mac bindings from the ARP and
> > -      IPv6 Neighbor Solicitation/Advertisement packets if ARP/ND lookup
> > -      failed in the previous table.
> > +      IPv6 Neighbor Solicitation/Advertisement packets if it is needed
> > +      according to the lookup results from the previous stage.
> >      </p>
> >
> >      <p>
> >        reg9[2] will be <code>1</code> if the
<code>lookup_arp/lookup_nd</code>
> > -      in the previous table was successful, or if there was no need to
do the
> > -      lookup.
> > +      in the previous table was successful or skipped, meaning no need
> > +      to learn mac binding from the packet.
> > +    </p>
> > +
> > +    <p>
> > +      reg9[3] will be <code>1</code> if the
> > +      <code>lookup_arp_ip/lookup_nd_ip</code> in the previous table was
> > +      successful or skipped, meaning it is ok to learn mac binding from
> > +      the packet (if reg9[2] is 0).
> >      </p>
> >
> >      <ul>
> >        <li>
> > -        A priority-100 flow with the match
> > -        <code>reg9[2] == 1</code> and advances the packet
> > -        to the next table as there is no need to learn the neighbor.
> > +        A priority-100 flow with the match <code>reg9[2] == 1 ||
reg9[3] ==
> > +        0</code> and advances the packet to the next table as there is
no need
> > +        to learn the neighbor.
> >        </li>
> >
> >        <li>
> > diff --git a/northd/ovn-northd.c b/northd/ovn-northd.c
> > index 5dd49f9..b7102b2 100644
> > --- a/northd/ovn-northd.c
> > +++ b/northd/ovn-northd.c
> > @@ -222,6 +222,7 @@ enum ovn_stage {
> >  /* Register to store the result of check_pkt_larger action. */
> >  #define REGBIT_PKT_LARGER        "reg9[1]"
> >  #define REGBIT_LOOKUP_NEIGHBOR_RESULT "reg9[2]"
> > +#define REGBIT_LOOKUP_NEIGHBOR_IP_RESULT "reg9[3]"
> >
> >  /* Register to store the eth address associated to a router port for
packets
> >   * received in S_ROUTER_IN_ADMISSION.
> > @@ -8442,36 +8443,62 @@ build_lrouter_flows(struct hmap *datapaths,
struct hmap *ports,
> >           * For ARP packets, table LOOKUP_NEIGHBOR does a lookup for the
> >           * (arp.spa, arp.sha) in the mac binding table using the
'lookup_arp'
> >           * action and stores the result in
REGBIT_LOOKUP_NEIGHBOR_RESULT bit.
> > +         * If "always_learn_from_arp_request" is set to false, it will
also
> > +         * lookup for the (arp.spa) in the mac binding table using the
> > +         * "lookup_arp_ip" action for ARP request packets, and stores
the
> > +         * result in REGBIT_LOOKUP_NEIGHBOR_IP_RESULT bit; or set that
bit
> > +         * to "1" directly for ARP response packets.
> >           *
> >           * For IPv6 ND NA packets, table LOOKUP_NEIGHBOR does a lookup
> >           * for the (nd.target, nd.tll) in the mac binding table using
the
> >           * 'lookup_nd' action and stores the result in
> > -         * REGBIT_LOOKUP_NEIGHBOR_RESULT bit.
> > +         * REGBIT_LOOKUP_NEIGHBOR_RESULT bit. If
> > +         * "always_learn_from_arp_request" is set to false,
> > +         * REGBIT_LOOKUP_NEIGHBOR_IP_RESULT bit is set.
> >           *
> >           * For IPv6 ND NS packets, table LOOKUP_NEIGHBOR does a lookup
> >           * for the (ip6.src, nd.sll) in the mac binding table using the
> >           * 'lookup_nd' action and stores the result in
> > -         * REGBIT_LOOKUP_NEIGHBOR_RESULT bit.
> > +         * REGBIT_LOOKUP_NEIGHBOR_RESULT bit. If
> > +         * "always_learn_from_arp_request" is set to false, it will
also lookup
> > +         * for the (ip6.src) in the mac binding table using the
"lookup_nd_ip"
> > +         * action and stores the result in
REGBIT_LOOKUP_NEIGHBOR_IP_RESULT
> > +         * bit.
> >           *
> >           * Table LEARN_NEIGHBOR learns the mac-binding using the action
> > -         * - 'put_arp/put_nd' only if REGBIT_LOOKUP_NEIGHBOR_RESULT bit
> > -         * is not set.
> > +         * - 'put_arp/put_nd'. Learning mac-binding is skipped if
> > +         *   REGBIT_LOOKUP_NEIGHBOR_RESULT bit is set or
> > +         *   REGBIT_LOOKUP_NEIGHBOR_IP_RESULT is not set.
> >           *
> >           * */
> >
> >          /* Flows for LOOKUP_NEIGHBOR. */
> > +        bool learn_from_arp_request = smap_get_bool(&od->nbr->options,
> > +            "always_learn_from_arp_request", true);
> > +        ds_clear(&actions);
> > +        ds_put_format(&actions, REGBIT_LOOKUP_NEIGHBOR_RESULT
> > +                      " = lookup_arp(inport, arp.spa, arp.sha);
%snext;",
> > +                      learn_from_arp_request ? "" :
> > +                      REGBIT_LOOKUP_NEIGHBOR_IP_RESULT" = 1; ");
> >          ovn_lflow_add(lflows, od, S_ROUTER_IN_LOOKUP_NEIGHBOR, 100,
> > -                      "arp.op == 2",
> > -                      REGBIT_LOOKUP_NEIGHBOR_RESULT" = "
> > -                      "lookup_arp(inport, arp.spa, arp.sha); next;");
> > +                      "arp.op == 2", ds_cstr(&actions));
> >
> > +        ds_clear(&actions);
> > +        ds_put_format(&actions, REGBIT_LOOKUP_NEIGHBOR_RESULT
> > +                      " = lookup_nd(inport, nd.target, nd.tll);
%snext;",
> > +                      learn_from_arp_request ? "" :
> > +                      REGBIT_LOOKUP_NEIGHBOR_IP_RESULT" = 1; ");
> >          ovn_lflow_add(lflows, od, S_ROUTER_IN_LOOKUP_NEIGHBOR, 100,
"nd_na",
> > -                      REGBIT_LOOKUP_NEIGHBOR_RESULT" = "
> > -                      "lookup_nd(inport, nd.target, nd.tll); next;");
> > +                      ds_cstr(&actions));
> >
> > +        ds_clear(&actions);
> > +        ds_put_format(&actions, REGBIT_LOOKUP_NEIGHBOR_RESULT
> > +                      " = lookup_nd(inport, ip6.src, nd.sll); %snext;",
> > +                      learn_from_arp_request ? "" :
> > +                      REGBIT_LOOKUP_NEIGHBOR_IP_RESULT
> > +                      " = lookup_nd_ip(inport, ip6.src); ");
> >          ovn_lflow_add(lflows, od, S_ROUTER_IN_LOOKUP_NEIGHBOR, 100,
"nd_ns",
> > -                      REGBIT_LOOKUP_NEIGHBOR_RESULT" = "
> > -                      "lookup_nd(inport, ip6.src, nd.sll); next;");
> > +                      ds_cstr(&actions));
> >
> >          /* For other packet types, we can skip neighbor learning.
> >           * So set REGBIT_LOOKUP_NEIGHBOR_RESULT to 1. */
> > @@ -8480,8 +8507,12 @@ build_lrouter_flows(struct hmap *datapaths,
struct hmap *ports,
> >
> >          /* Flows for LEARN_NEIGHBOR. */
> >          /* Skip Neighbor learning if not required. */
> > +        ds_clear(&match);
> > +        ds_put_format(&match, REGBIT_LOOKUP_NEIGHBOR_RESULT" == 1%s",
> > +                      learn_from_arp_request ? "" :
> > +                      " || "REGBIT_LOOKUP_NEIGHBOR_IP_RESULT" == 0");
> >          ovn_lflow_add(lflows, od, S_ROUTER_IN_LEARN_NEIGHBOR, 100,
> > -                      REGBIT_LOOKUP_NEIGHBOR_RESULT" == 1", "next;");
> > +                      ds_cstr(&match), "next;");
> >
> >          ovn_lflow_add(lflows, od, S_ROUTER_IN_LEARN_NEIGHBOR, 90,
> >                        "arp", "put_arp(inport, arp.spa, arp.sha);
next;");
> > @@ -8498,8 +8529,37 @@ build_lrouter_flows(struct hmap *datapaths,
struct hmap *ports,
> >              continue;
> >          }
> >
> > +        bool learn_from_arp_request =
smap_get_bool(&op->od->nbr->options,
> > +            "always_learn_from_arp_request", true);
> > +
> >          /* Check if we need to learn mac-binding from ARP requests. */
> >          for (int i = 0; i < op->lrp_networks.n_ipv4_addrs; i++) {
> > +            if (!learn_from_arp_request) {
> > +                /* ARP request to this address should always get
learned,
> > +                 * so add a priority-110 flow to set
> > +                 * REGBIT_LOOKUP_NEIGHBOR_IP_RESULT to 1. */
> > +                ds_clear(&match);
> > +                ds_put_format(&match,
> > +                              "inport == %s && arp.spa == %s/%u && "
> > +                              "arp.tpa == %s && arp.op == 1",
> > +                              op->json_key,
> > +                              op->lrp_networks.ipv4_addrs[i].network_s,
> > +                              op->lrp_networks.ipv4_addrs[i].plen,
> > +                              op->lrp_networks.ipv4_addrs[i].addr_s);
> > +                if (op->od->l3dgw_port && op == op->od->l3dgw_port
> > +                    && op->od->l3redirect_port) {
> > +                    ds_put_format(&match, " &&
is_chassis_resident(%s)",
> > +                                  op->od->l3redirect_port->json_key);
> > +                }
> > +                const char *actions_s = REGBIT_LOOKUP_NEIGHBOR_RESULT
> > +                                  " = lookup_arp(inport, arp.spa,
arp.sha); "
> > +                                  REGBIT_LOOKUP_NEIGHBOR_IP_RESULT" =
1;"
> > +                                  " next;";
> > +                ovn_lflow_add_with_hint(lflows, op->od,
> > +                                        S_ROUTER_IN_LOOKUP_NEIGHBOR,
110,
> > +                                        ds_cstr(&match), actions_s,
> > +                                        &op->nbrp->header_);
> > +            }
> >              ds_clear(&match);
> >              ds_put_format(&match,
> >                            "inport == %s && arp.spa == %s/%u && arp.op
== 1",
> > @@ -8511,12 +8571,16 @@ build_lrouter_flows(struct hmap *datapaths,
struct hmap *ports,
> >                  ds_put_format(&match, " && is_chassis_resident(%s)",
> >                                op->od->l3redirect_port->json_key);
> >              }
> > +            ds_clear(&actions);
> > +            ds_put_format(&actions, REGBIT_LOOKUP_NEIGHBOR_RESULT
> > +                          " = lookup_arp(inport, arp.spa, arp.sha);
%snext;",
> > +                          learn_from_arp_request ? "" :
> > +                          REGBIT_LOOKUP_NEIGHBOR_IP_RESULT
> > +                          " = lookup_arp_ip(inport, arp.spa); ");
> >              ovn_lflow_add_with_hint(lflows, op->od,
> >                                      S_ROUTER_IN_LOOKUP_NEIGHBOR, 100,
> > -                                    ds_cstr(&match),
> > -                                    REGBIT_LOOKUP_NEIGHBOR_RESULT" = "
> > -                                    "lookup_arp(inport, arp.spa,
arp.sha); "
> > -                                    "next;", &op->nbrp->header_);
> > +                                    ds_cstr(&match), ds_cstr(&actions),
> > +                                    &op->nbrp->header_);
> >          }
> >      }
> >
> > diff --git a/ovn-nb.xml b/ovn-nb.xml
> > index 4c59338..d0317db 100644
> > --- a/ovn-nb.xml
> > +++ b/ovn-nb.xml
> > @@ -1859,6 +1859,33 @@
> >            send traffic between each other.
> >          </p>
> >        </column>
> > +      <column name="options" key="always_learn_from_arp_request"
type='{"type": "boolean"}'>
> > +        <p>
> > +          This option controls the behavior when handling IPv4 ARP
requests or
> > +          IPv6 ND-NS packets - whether a dynamic neighbor (MAC
binding) entry
> > +          is added/updated.
> > +        </p>
> > +
> > +        <p>
> > +          <code>true</code> - Always learn the MAC-IP binding, and
add/update
> > +          the MAC binding entry.
> > +        </p>
> > +
> > +        <p>
> > +          <code>false</code> - If there is a MAC binding for that IP
and the
> > +          MAC is different, or, if TPA of ARP request belongs to any
router
> > +          port on this router, then update/add that MAC-IP binding.
Otherwise,
> > +          don't update/add entries.
> > +        </p>
> > +
> > +        <p>
> > +          It is <code>true</code> by default.  It is recommended to
set to
> > +          <code>false</code> when a large number of logical routers are
> > +          connected to the same logical switch but most of them never
need to
> > +          send traffic between each other, to reduce the size of the
MAC
> > +          binding table.
> > +        </p>
> > +      </column>
> >      </group>
> >
> >      <group title="Common Columns">
> > diff --git a/tests/ovn.at b/tests/ovn.at
> > index 33fa6f2..ef5ef12 100644
> > --- a/tests/ovn.at
> > +++ b/tests/ovn.at
> > @@ -4042,6 +4042,18 @@ ip_to_hex() {
> >  sha=f00000000011
> >  spa=`ip_to_hex 192 168 1 100`
> >  tpa=$spa
> > +
> > +# When always_learn_from_arp_request=false, the new mac-binding will
not be learned
> > +# through GARP request.
> > +ovn-nbctl --wait=hv set logical_router lr0
options:always_learn_from_arp_request=false
> > +
> > +test_arp 11 $sha $spa $tpa
> > +sleep 1
>
> Is it possible to use ovn-nbctl --wait=hv sync instead of sleep 1 ?

Hi Numan, I thought about this, but since mac_binding learning is triggered
by the data plane ARP packets instead of only DB changes, "ovn-nbctl
--wait=hv sync" may still not help in race conditions. So sleep is the best
way I can think of for now. (I replied to this same comment from your
earlier email, but maybe you didn't notice it)

>
>
> > +AT_CHECK([ovn-sbctl find mac_binding ip="192.168.1.100"], [0], [])
> > +
> > +# When always_learn_from_arp_request=true, the new mac-binding will be
learned.
> > +ovn-nbctl --wait=hv set logical_router lr0
options:always_learn_from_arp_request=true
> > +
> >  test_arp 11 $sha $spa $tpa
> >  OVS_WAIT_UNTIL([test `ovn-sbctl find mac_binding ip="192.168.1.100" |
wc -l` -gt 0])
> >  ovn-nbctl --wait=hv sync
> > @@ -4056,6 +4068,12 @@ test_ip 21 $smac $dmac $sip $dip 11
> >
> >  # lp12 send GARP request to announce ownership of 192.168.1.100.
> >
> > +# Even when always_learn_from_arp_request=false, the existing
mac-binding should be
> > +# updated through GARP request.
> > +ovn-nbctl --wait=hv set logical_router lr0
options:always_learn_from_arp_request=false
> > +ovn-sbctl lflow-list
> > +as hv2 ovs-ofctl dump-flows br-int
>
> Are these above 2 leftover after debugging ? I think you can delete them.
>
Ack.

Thanks,
Han

>
> > +
> >  sha=f00000000012
> >  test_arp 12 $sha $spa $tpa
> >  OVS_WAIT_UNTIL([ovn-sbctl find mac_binding ip="192.168.1.100" | grep
f0:00:00:00:00:12])
> > --
> > 2.1.0
> >
> > _______________________________________________
> > dev mailing list
> > [email protected]
> > https://mail.openvswitch.org/mailman/listinfo/ovs-dev
> >
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