diff --git a/src/yggdrasil/multicast.go b/src/yggdrasil/multicast.go index dacad27..ca3a1f7 100644 --- a/src/yggdrasil/multicast.go +++ b/src/yggdrasil/multicast.go @@ -122,11 +122,48 @@ func (m *multicast) announce() { // There might be interfaces that we configured listeners for but are no // longer up - if that's the case then we should stop the listeners for name, listener := range m.listeners { - if _, ok := interfaces[name]; !ok { + // Prepare our stop function! + stop := func() { listener.stop <- true delete(m.listeners, name) m.core.log.Debugln("No longer multicasting on", name) } + // If the interface is no longer visible on the system then stop the + // listener, as another one will be started further down + if _, ok := interfaces[name]; !ok { + stop() + continue + } + // It's possible that the link-local listener address has changed so if + // that is the case then we should clean up the interface listener + found := false + listenaddr, err := net.ResolveTCPAddr("tcp6", listener.listener.Addr().String()) + if err != nil { + stop() + continue + } + // Find the interface that matches the listener + if intf, err := net.InterfaceByName(name); err == nil { + if addrs, err := intf.Addrs(); err == nil { + // Loop through the addresses attached to that listener and see if any + // of them match the current address of the listener + for _, addr := range addrs { + if ip, _, err := net.ParseCIDR(addr.String()); err == nil { + // Does the interface address match our listener address? + if ip.Equal(listenaddr.IP) { + found = true + break + } + } + } + } + } + // If the address has not been found on the adapter then we should stop + // and clean up the TCP listener. A new one will be created below if a + // suitable link-local address is found + if !found { + stop() + } } // Now that we have a list of valid interfaces from the operating system, // we can start checking if we can send multicasts on them