[client] Remove endpoint address on peer disconnect, retain status for activity recording (#4228)

* When a peer disconnects, remove the endpoint address to avoid sending traffic to a non-existent address, but retain the status for the activity recorder.

client/internal/engine_test.go

@@ -105,6 +105,10 @@ type MockWGIface struct {
 	LastActivitiesFunc         func() map[string]monotime.Time
 }
 
+func (m *MockWGIface) RemoveEndpointAddress(_ string) error {
+	return nil
+}
+
 func (m *MockWGIface) FullStats() (*configurer.Stats, error) {
 	return nil, fmt.Errorf("not implemented")
 }

client/internal/iface_common.go

@@ -28,6 +28,7 @@ type wgIfaceBase interface {
 	UpdateAddr(newAddr string) error
 	GetProxy() wgproxy.Proxy
 	UpdatePeer(peerKey string, allowedIps []netip.Prefix, keepAlive time.Duration, endpoint *net.UDPAddr, preSharedKey *wgtypes.Key) error
+	RemoveEndpointAddress(key string) error
 	RemovePeer(peerKey string) error
 	AddAllowedIP(peerKey string, allowedIP netip.Prefix) error
 	RemoveAllowedIP(peerKey string, allowedIP netip.Prefix) error

client/internal/peer/conn.go

@@ -430,6 +430,9 @@ func (conn *Conn) onICEStateDisconnected() {
 	} else {
 		conn.Log.Infof("ICE disconnected, do not switch to Relay. Reset priority to: %s", conntype.None.String())
 		conn.currentConnPriority = conntype.None
+		if err := conn.config.WgConfig.WgInterface.RemoveEndpointAddress(conn.config.WgConfig.RemoteKey); err != nil {
+			conn.Log.Errorf("failed to remove wg endpoint: %v", err)
+		}
 	}
 
 	changed := conn.statusICE.Get() != worker.StatusDisconnected
@@ -523,6 +526,9 @@ func (conn *Conn) onRelayDisconnected() {
 	if conn.currentConnPriority == conntype.Relay {
 		conn.Log.Debugf("clean up WireGuard config")
 		conn.currentConnPriority = conntype.None
+		if err := conn.config.WgConfig.WgInterface.RemoveEndpointAddress(conn.config.WgConfig.RemoteKey); err != nil {
+			conn.Log.Errorf("failed to remove wg endpoint: %v", err)
+		}
 	}
 
 	if conn.wgProxyRelay != nil {

client/internal/peer/iface.go

@@ -18,4 +18,5 @@ type WGIface interface {
 	GetStats() (map[string]configurer.WGStats, error)
 	GetProxy() wgproxy.Proxy
 	Address() wgaddr.Address
+	RemoveEndpointAddress(key string) error
 }