mounttablelib: Let users of neighborhood allow passibe subscription.
If the host name is underscore, "_", then do not become
an active member of the "vanadium" mdns multicast group.
Change-Id: Ie0ffc7191b20d17cf292571c857f12da496366a9
diff --git a/services/mounttable/mounttablelib/neighborhood.go b/services/mounttable/mounttablelib/neighborhood.go
index b2a2a71..ac82af2 100644
--- a/services/mounttable/mounttablelib/neighborhood.go
+++ b/services/mounttable/mounttablelib/neighborhood.go
@@ -34,15 +34,21 @@
errDoesntImplementUnmount = verror.Register(pkgPath+".errDoesntImplementUnmount", verror.NoRetry, "{1:}{2:} this server does not implement Unmount{:_}")
errDoesntImplementDelete = verror.Register(pkgPath+".errDoesntImplementDelete", verror.NoRetry, "{1:}{2:} this server does not implement Delete{:_}")
errDoesntImplementSetPermissions = verror.Register(pkgPath+".errDoesntImplementSetPermissions", verror.NoRetry, "{1:}{2:} this server does not implement SetPermissions{:_}")
+ errSlashInHostName = verror.Register(pkgPath+".errSlashInHostName", verror.NoRetry, "{1:}{2:} hostname may not contain '/'{:_}")
)
const addressPrefix = "address:"
+// AnonymousNeighbor is the neighborhood host name to use if you want to be a client of the neighborhood namespace
+// without appearing in it.
+const AnonymousNeighbor = "_"
+
// neighborhood defines a set of machines on the same multicast media.
type neighborhood struct {
- mdns *mdns.MDNS
- nelems int
- nw netconfig.NetConfigWatcher
+ mdns *mdns.MDNS
+ nelems int
+ nw netconfig.NetConfigWatcher
+ lastSubscription time.Time
}
var _ rpc.Dispatcher = (*neighborhood)(nil)
@@ -81,6 +87,10 @@
}
func newNeighborhood(host string, addresses []string, loopback bool) (*neighborhood, error) {
+ if strings.Contains(host, "/") {
+ return nil, verror.New(errSlashInHostName, nil)
+ }
+
// Create the TXT contents with addresses to announce. Also pick up a port number.
var txt []string
var port uint16
@@ -105,7 +115,10 @@
}
vlog.VI(2).Infof("listening for service vanadium on port %d", port)
mdns.SubscribeToService("vanadium")
- mdns.AddService("vanadium", "", port, txt...)
+ if host != AnonymousNeighbor {
+ mdns.AddService("vanadium", "", port, txt...)
+ }
+ time.Sleep(50 * time.Millisecond)
nh := &neighborhood{
mdns: mdns,
@@ -199,6 +212,12 @@
// neighbors returns all neighbors and their MountedServer structs.
func (nh *neighborhood) neighbors() map[string][]naming.MountedServer {
+ // If we haven't refreshed in a while, do it now.
+ if time.Now().Sub(nh.lastSubscription) > time.Duration(30)*time.Second {
+ nh.mdns.SubscribeToService("vanadium")
+ time.Sleep(50 * time.Millisecond)
+ nh.lastSubscription = time.Now()
+ }
neighbors := make(map[string][]naming.MountedServer, 0)
members := nh.mdns.ServiceDiscovery("vanadium")
for _, m := range members {
