wireguard: T5707: remove previously deconfigured peer

Changing the public key of a peer (updating the key material) left the old
WireGuard peer in place, as the key removal command used the new key.

WireGuard only supports peer removal based on the configured public-key, by
deleting the entire interface this is the shortcut instead of parsing out all
peers and removing them one by one.

Peer reconfiguration will always come with a short downtime while the WireGuard
interface is recreated.

1 files changed, 17 insertions, 16 deletions

diff --git a/src/conf_mode/interfaces-wireguard.py b/src/conf_mode/interfaces-wireguard.py
index 122d9589a..79e5d3f44 100755
--- a/src/conf_mode/interfaces-wireguard.py
+++ b/src/conf_mode/interfaces-wireguard.py
@@ -51,17 +51,9 @@ def get_config(config=None):
     tmp = is_node_changed(conf, base + [ifname, 'port'])
     if tmp: wireguard['port_changed'] = {}
 
-    # Determine which Wireguard peer has been removed.
-    # Peers can only be removed with their public key!
-    if 'peer' in wireguard:
-        peer_remove = {}
-        for peer, peer_config in wireguard['peer'].items():
-            # T4702: If anything on a peer changes we remove the peer first and re-add it
-            if is_node_changed(conf, base + [ifname, 'peer', peer]):
-                if 'public_key' in peer_config:
-                    peer_remove = dict_merge({'peer_remove' : {peer : peer_config['public_key']}}, peer_remove)
-        if peer_remove:
-           wireguard.update(peer_remove)
+    # T4702: If anything on a peer changes we remove the peer first and re-add it
+    if is_node_changed(conf, base + [ifname, 'peer']):
+        wireguard.update({'rebuild_required': {}})
 
     return wireguard
 
@@ -113,12 +105,21 @@ def verify(wireguard):
         public_keys.append(peer['public_key'])
 
 def apply(wireguard):
-    tmp = WireGuardIf(wireguard['ifname'])
-    if 'deleted' in wireguard:
-        tmp.remove()
-        return None
+    if 'rebuild_required' in wireguard or 'deleted' in wireguard:
+        wg = WireGuardIf(**wireguard)
+        # WireGuard only supports peer removal based on the configured public-key,
+        # by deleting the entire interface this is the shortcut instead of parsing
+        # out all peers and removing them one by one.
+        #
+        # Peer reconfiguration will always come with a short downtime while the
+        # WireGuard interface is recreated (see below)
+        wg.remove()
+
+    # Create the new interface if required
+    if 'deleted' not in wireguard:
+        wg = WireGuardIf(**wireguard)
+        wg.update(wireguard)
 
-    tmp.update(wireguard)
     return None
 
 if __name__ == '__main__':