vyos-netlinkd: T8047: replace netplugd

Implementing a daemon that listens for netlink messages in Python was discussed
for many years. This is a proof-of-concept implementation how we can listen for
netlink messages and process them in Python.

Python 3.10 minimum is required due to the use of case statements which mimics
C-style switch/case instructions.

Add example:

 set interfaces ethernet eth1 vif 21 address dhcp
 set interfaces ethernet eth1 vif 21 address dhcpv6
 commit

If network cable is unplugged:

  vyos-netlinkd[12681]: RTM_NEWLINK -> eth3.10, state=DOWN, mac=00:50:56:b3:9d:8e
  vyos-netlinkd[12681]: Stopping dhclient@eth3.10.service...
  vyos-netlinkd[12681]: Stopping dhcp6c@eth3.10.service...

If cable is plugged back in:

  vyos-netlinkd[12681]: RTM_NEWLINK -> eth3.10, state=DOWN, mac=00:50:56:b3:9d:8e
  vyos-netlinkd[12681]: RTM_NEWLINK -> eth3.10, state=UP, mac=00:50:56:b3:9d:8e
  vyos-netlinkd[12681]: Restarting dhclient@eth3.10.service...
  vyos-netlinkd[12681]: Restarting dhcp6c@eth3.10.service...

1 files changed, 6 insertions, 2 deletions

diff --git a/src/init/vyos-router b/src/init/vyos-router
index 550c916a1..de3cc071a 100755
--- a/src/init/vyos-router
+++ b/src/init/vyos-router
@@ -681,13 +681,18 @@ start ()
     fi
 
     # Start netplug daemon
-    systemctl start netplug.service
+    systemctl start vyos-netlinkd.service
 }
 
 stop()
 {
     local -i status=0
     log_daemon_msg "Stopping VyOS router"
+
+    # As vyos-netlinkd consumes a configuration, we need to stop it prior
+    # unmounting /config
+    systemctl stop vyos-netlinkd.service
+
     for ((i=${#sub_inits[@]} - 1; i >= 0; i--)) ; do
     s=${subinit[$i]}
     log_progress_msg $s
@@ -699,7 +704,6 @@ stop()
     umount ${vyatta_configdir}
     log_action_end_msg $?
 
-    systemctl stop netplug.service
     systemctl stop vyconfd.service
     systemctl stop frr.service