Change Details

**Summary** Static ARP entries are not synchronized with the VPP dataplane after any changes are made on the VPP side that require the dataplane restart. **How to reproduce** Configure VPP with basic settings: ``` set interfaces ethernet eth9 address '192.168.122.5/24' set system option kernel cpu disable-nmi-watchdog set system option kernel cpu isolate-cpus '2-3' set system option kernel cpu nohz-full '2-3' set system option kernel cpu rcu-no-cbs '2-3' set system option kernel disable-hpet set system option kernel disable-mce set system option kernel disable-mitigations set system option kernel disable-softlockup set system option kernel memory hugepage-size 2M hugepage-count '1024' set vpp settings cpu corelist-workers '3' set vpp settings cpu main-core '2' set vpp settings interface eth9 driver 'dpdk' set vpp settings memory main-heap-size '1G' set vpp settings unix poll-sleep-usec '1000' ``` Check neighbors: ``` vyos@vyos# sudo vppctl show ip neighbors Age IP Flags Ethernet Interface 266.8925 192.168.122.1 D 52:54:00:97:31:8f eth9 ``` Add static ARP entries: ``` set protocols static arp interface eth9 address 192.168.122.2 mac '00:11:22:33:44:55' set protocols static arp interface eth9 address 192.168.122.3 mac '00:11:22:33:44:66' ``` Check neighbors again: ``` vyos@vyos# sudo vppctl show ip neighbors Age IP Flags Ethernet Interface 49.0414 192.168.122.3 S 00:11:22:33:44:66 eth9 49.0425 192.168.122.2 S 00:11:22:33:44:55 eth9 330.6885 192.168.122.1 D 52:54:00:97:31:8f eth9 ``` Update VPP settings to trigger a dataplane restart: ``` set vpp settings interface eth8 driver 'dpdk' ``` Check neighbors again: ``` vyos@vyos# sudo vppctl show ip neighbors Age IP Flags Ethernet Interface 1.6877 192.168.122.1 D 52:54:00:97:31:8f eth9 ``` **What is expected / Suggested solution** It is expected that static ARP entries will not disappear after the VPP restart. The optimal solution would be to introduce the same logic as we [have with FIB](https://github.com/vyos/vyos-1x/blob/fd8794f36b487ba2102cc50437056e93eb62f7f3/src/conf_mode/vpp.py#L747). If this is not possible, then we can do the synchronization manually, [using ip_neighbor_add_del()](https://github.com/FDio/vpp/blob/f40fcee5b1b53e62f23db7b4fe509edadfdc65dd/src/vnet/ip-neighbor/ip_neighbor.api#L61C8-L61C27), but netlink/dump -> install seems to be much better.

**Summary** VPP add static ARP neighbor entries configurableStatic ARP entries are not synchronized with the VPP dataplane after any changes are made on the VPP side that require the dataplane restart. **Use case****How to reproduce** Configure static entries explicitly and not rely on the Linux kernel netlink messages.VPP with basic settings: **Additional information**``` set interfaces ethernet eth9 address '192.168.122.5/24' set system option kernel cpu disable-nmi-watchdog set system option kernel cpu isolate-cpus '2-3' set system option kernel cpu nohz-full '2-3' set system option kernel cpu rcu-no-cbs '2-3' set system option kernel disable-hpet set system option kernel disable-mce set system option kernel disable-mitigations set system option kernel disable-softlockup set system option kernel memory hugepage-size 2M hugepage-count '1024' set vpp settings cpu corelist-workers '3' set vpp settings cpu main-core '2' set vpp settings interface eth9 driver 'dpdk' set vpp settings memory main-heap-size '1G' set vpp settings unix poll-sleep-usec '1000' ``` Check neighbors: ``` vppctl set ip neighbor eth4 192.0.2.2 xxxx.xxxx.xxxxyos@vyos# sudo vppctl show ip neighbors Age IP Flags Ethernet Interface 266.8925 192.168.122.1 D 52:54:00:97:31:8f eth9 ``` Add static ARP entries: ``` set protocols static arp interface eth9 address 192.168.122.2 mac '00:11:22:33:44:55' set protocols static arp interface eth9 address 192.168.122.3 mac '00:11:22:33:44:66' ``` Check neighbors again: ``` vyos@vyos# sudo vppctl show ip neighbors Age IP Flags Ethernet Interface 49.0414 192.168.122.3 S 00:11:22:33:44:66 eth9 49.0425 192.168.122.2 S 00:11:22:33:44:55 eth9 330.6885 192.168.122.1 D 52:54:00:97:31:8f eth9 ``` Update VPP settings to trigger a dataplane restart: ``` set vpp settings interface eth8 driver 'dpdk' ``` Check neighbors again: ``` vyos@vyos# sudo vppctl show ip neighbors Age IP Flags Ethernet Interface 1.6877 192.168.122.1 D 52:54:00:97:31:8f eth9 ``` **What is expected / Suggested solution** It is expected that static ARP entries will not disappear after the VPP restart. The optimal solution would be to introduce the same logic as we [have with FIB](https://github.com/vyos/vyos-1x/blob/fd8794f36b487ba2102cc50437056e93eb62f7f3/src/conf_mode/vpp.py#L747). If this is not possible, then we can do the synchronization manually, [using ip_neighbor_add_del()](https://github.com/FDio/vpp/blob/f40fcee5b1b53e62f23db7b4fe509edadfdc65dd/src/vnet/ip-neighbor/ip_neighbor.api#L61C8-L61C27), but netlink/dump -> install seems to be much better.