controller: Add lsp option disable_garp_rarp.

If the lsp option 'disable_garp_rarp' is set to true,
GARP and RARP announcements are not sent by ovn when a
VIF port is created on a bridged logical switch.

Usecase
========
This option is useful during VM migration to let the
hypervisor/VM send the RARP/GARP once VM is ready to
process the packets post migration. This helps to reduce
downtime during VM migration.

Signed-off-by: Shibir Basak <shibir.basak@nutanix.com>
Acked-by: Naveen Yerramneni <naveen.yerramneni@nutanix.com>
Signed-off-by: Numan Siddique <numans@ovn.org>

NEWS

@@ -47,6 +47,9 @@ Post v24.03.0
   - Add support for CT zone limit that can be specified per LR
     (options:ct-zone-limit), LS (other_config:ct-zone-limit) or LSP
     (options:ct-zone-limit).
+  - A new LSP option "disable_garp_rarp" has been added to prevent OVN from
+    sending GARP or RARP announcements when a VIF is created on a bridged
+    logical switch.
 
 OVN v24.03.0 - 01 Mar 2024
 --------------------------

controller/pinctrl.c

@@ -6612,7 +6612,7 @@ send_garp_rarp_prepare(struct ovsdb_idl_txn *ovnsb_idl_txn,
     SSET_FOR_EACH (iface_id, &localnet_vifs) {
         const struct sbrec_port_binding *pb = lport_lookup_by_name(
             sbrec_port_binding_by_name, iface_id);
-        if (pb) {
+        if (pb && !smap_get_bool(&pb->options, "disable_garp_rarp", false)) {
             send_garp_rarp_update(ovnsb_idl_txn,
                                   sbrec_mac_binding_by_lport_ip,
                                   local_datapaths, pb, &nat_addresses,
@@ -6625,7 +6625,7 @@ send_garp_rarp_prepare(struct ovsdb_idl_txn *ovnsb_idl_txn,
     SSET_FOR_EACH (gw_port, &local_l3gw_ports) {
         const struct sbrec_port_binding *pb
             = lport_lookup_by_name(sbrec_port_binding_by_name, gw_port);
-        if (pb) {
+        if (pb && !smap_get_bool(&pb->options, "disable_garp_rarp", false)) {
             send_garp_rarp_update(ovnsb_idl_txn, sbrec_mac_binding_by_lport_ip,
                                   local_datapaths, pb, &nat_addresses,
                                   garp_max_timeout, garp_continuous);

ovn-nb.xml

@@ -1329,6 +1329,13 @@
           The default value is <code>false</code>.
         </column>
 
+        <column name="options" key="disable_garp_rarp"
+                type='{"type": "boolean"}'>
+          If set to <code>true</code>, GARP and RARP announcements are not
+          sent when a VIF port is created on a bridged logical switch.
+          The default value is <code>false</code>.
+        </column>
+
         <column name="options" key="pkt_clone_type"
                 type='{"type": "string", "enum": ["set", ["mc_unknown"]]}'>
           If set to mc_unknown, packets going to this VIF get cloned to all

tests/ovn.at

@@ -25012,6 +25012,74 @@ OVN_CLEANUP([hv1])
 AT_CLEANUP
 ])
 
+OVN_FOR_EACH_NORTHD([
+AT_SETUP([Disabling RARP/GARP announcements])
+ovn_start
+
+# In this test case we create 1 switch and bring up 4 VIFs on it.
+# Two VIFs will be assigned MAC addresses only (i.e. without ips)
+# and two VIFs will be assigned IP addresses along with MAC addresses.
+# VIFs with IPs are supposed to send GARPs and VIFs with only MAC
+# addresses are supposed to send RARP. However, we test the lsp
+# option disable_garp_rarp, which when set to true for an lsp does
+# not send the GARP/RARP announcements.
+
+ovn-nbctl ls-add ls1
+ovn-nbctl lsp-add ls1 ln1 "" 101
+ovn-nbctl lsp-set-addresses ln1 unknown
+ovn-nbctl lsp-set-type ln1 localnet
+ovn-nbctl lsp-set-options ln1 network_name=phys
+
+ovn-nbctl lsp-add ls1 lp11
+ovn-nbctl lsp-set-addresses lp11 "f0:00:00:00:00:11"
+
+ovn-nbctl lsp-add ls1 lp12
+ovn-nbctl lsp-set-addresses lp12 "f0:00:00:00:00:12"
+ovn-nbctl set logical_switch_port lp12 options:disable_garp_rarp=true
+
+ovn-nbctl lsp-add ls1 lp13
+ovn-nbctl lsp-set-addresses lp13 "f0:00:00:00:00:13 192.168.1.3"
+
+ovn-nbctl lsp-add ls1 lp14
+ovn-nbctl lsp-set-addresses lp14 "f0:00:00:00:00:14 192.168.1.4"
+ovn-nbctl set logical_switch_port lp14 options:disable_garp_rarp=true
+
+net_add n1
+
+sim_add hv1
+as hv1
+ovs-vsctl add-br br-phys
+ovs-vsctl set open . external-ids:ovn-bridge-mappings=phys:br-phys
+ovn_attach n1 br-phys 192.168.0.1
+
+AT_CHECK([ovs-vsctl add-port br-phys snoopvif -- set Interface snoopvif options:tx_pcap=hv1/snoopvif-tx.pcap options:rxq_pcap=hv1/snoopvif-rx.pcap])
+
+ovs-vsctl add-port br-int vif11 -- \
+    set Interface vif11 external-ids:iface-id=lp11
+
+ovs-vsctl add-port br-int vif12 -- \
+    set Interface vif12 external-ids:iface-id=lp12
+
+ovs-vsctl add-port br-int vif13 -- \
+    set Interface vif13 external-ids:iface-id=lp13
+
+ovs-vsctl add-port br-int vif14 -- \
+    set Interface vif14 external-ids:iface-id=lp14
+
+wait_for_ports_up
+ovn-nbctl --wait=sb sync
+
+# RARP packet for lp11
+echo "fffffffffffff000000000118100006580350001080006040003f0000000001100000000f0000000001100000000" > expected
+# GARP packet for lp13
+echo "fffffffffffff000000000138100006508060001080006040001f00000000013c0a80103000000000000c0a80103" >> expected
+OVN_CHECK_PACKETS_UNIQ([hv1/snoopvif-tx.pcap], [expected])
+
+OVN_CLEANUP([hv1])
+
+AT_CLEANUP
+])
+
 OVN_FOR_EACH_NORTHD([
 AT_SETUP([Stateless Floating IP])
 ovn_start