Get peers from namespaces where shared nodes are shared to

This is rather shameful. Shared nodes should have never worked without this.

machine.go

@@ -78,13 +78,13 @@ func (h *Headscale) getDirectPeers(m *Machine) (Machines, error) {
 	return machines, nil
 }
 
+// getShared fetches machines that are shared to the `Namespace` of the machine we are getting peers for
 func (h *Headscale) getShared(m *Machine) (Machines, error) {
 	log.Trace().
 		Str("func", "getShared").
 		Str("machine", m.Name).
 		Msg("Finding shared peers")
 
-	// We fetch here machines that are shared to the `Namespace` of the machine we are getting peers for
 	sharedMachines := []SharedMachine{}
 	if err := h.db.Preload("Namespace").Preload("Machine").Where("namespace_id = ?",
 		m.NamespaceID).Find(&sharedMachines).Error; err != nil {
@@ -105,6 +105,37 @@ func (h *Headscale) getShared(m *Machine) (Machines, error) {
 	return peers, nil
 }
 
+// getSharedTo fetches the machines of the namespaces this machine is shared in
+func (h *Headscale) getSharedTo(m *Machine) (Machines, error) {
+	log.Trace().
+		Str("func", "getSharedTo").
+		Str("machine", m.Name).
+		Msg("Finding peers in namespaces this machine is shared with")
+
+	sharedMachines := []SharedMachine{}
+	if err := h.db.Preload("Namespace").Preload("Machine").Where("machine_id = ?",
+		m.ID).Find(&sharedMachines).Error; err != nil {
+		return Machines{}, err
+	}
+
+	peers := make(Machines, 0)
+	for _, sharedMachine := range sharedMachines {
+		namespaceMachines, err := h.ListMachinesInNamespace(sharedMachine.Namespace.Name)
+		if err != nil {
+			return Machines{}, err
+		}
+		peers = append(peers, *namespaceMachines...)
+	}
+
+	sort.Slice(peers, func(i, j int) bool { return peers[i].ID < peers[j].ID })
+
+	log.Trace().
+		Str("func", "getSharedTo").
+		Str("machine", m.Name).
+		Msgf("Found peers we are shared with: %s", peers.String())
+	return peers, nil
+}
+
 func (h *Headscale) getPeers(m *Machine) (Machines, error) {
 	direct, err := h.getDirectPeers(m)
 	if err != nil {
@@ -118,13 +149,24 @@ func (h *Headscale) getPeers(m *Machine) (Machines, error) {
 	shared, err := h.getShared(m)
 	if err != nil {
 		log.Error().
-			Str("func", "getDirectPeers").
+			Str("func", "getShared").
+			Err(err).
+			Msg("Cannot fetch peers")
+		return Machines{}, err
+	}
+
+	sharedTo, err := h.getSharedTo(m)
+	if err != nil {
+		log.Error().
+			Str("func", "sharedTo").
 			Err(err).
 			Msg("Cannot fetch peers")
 		return Machines{}, err
 	}
 
 	peers := append(direct, shared...)
+	peers = append(peers, sharedTo...)
+
 	sort.Slice(peers, func(i, j int) bool { return peers[i].ID < peers[j].ID })
 
 	log.Trace().