Fold the rebind counter and traffic flags into one atomic word (#1820)

inside.go

@@ -160,21 +160,18 @@ func (f *Interface) sendInsideMessage(hostinfo *HostInfo, pkt tio.Packet, nb []b
 	// One traffic-out mark covers every segment of the superpacket; doing it
 	// per segment in sendInsideEncrypt paid an atomic store up to ~45 extra
 	// times per TSO packet, inside writeLock under boring crypto.
-	f.connectionManager.Out(hostinfo)
-
-	remote := hostinfo.GetRemote()
-	if hostinfo.lastRebindCount != f.rebindCount {
-		//NOTE: there is an update hole if a tunnel isn't used and exactly 256 rebinds occur before the tunnel is
-		// finally used again. This tunnel would eventually be torn down and recreated if this action didn't help.
+	//
+	// We rebound since this tunnel last sent, ask the lighthouse to get the far side punching at us again
+	if f.connectionManager.Out(hostinfo) {
 		f.lightHouse.QueryServer(hostinfo.vpnAddrs[0])
-		hostinfo.lastRebindCount = f.rebindCount
 		if f.l.Enabled(context.Background(), slog.LevelDebug) {
-			hostinfo.logger(f.l).Debug("Lighthouse update triggered for punch due to rebind counter",
+			hostinfo.logger(f.l).Debug("Lighthouse update triggered for punch due to rebind epoch",
 				"vpnAddrs", hostinfo.vpnAddrs,
 			)
 		}
 	}
 
+	remote := hostinfo.GetRemote()
 	if !remote.IsValid() { //the relay path
 		//first, find our relay hostinfo:
 		var relayHostInfo *HostInfo
@@ -460,7 +457,7 @@ func (f *Interface) prepareSendVia(via *HostInfo,
 	}
 
 	out = header.Encode(out, header.Version, header.Message, header.MessageRelay, relay.RemoteIndex, c)
-	f.connectionManager.Out(via)
+	f.connectionManager.OutNoRebind(via)
 
 	// Authenticate the header and payload, but do not encrypt for this message type.
 	// The payload consists of the inner, unencrypted Nebula header, as well as the end-to-end encrypted payload.
@@ -553,17 +550,13 @@ func (f *Interface) sendNoMetrics(t header.MessageType, st header.MessageSubType
 
 	//l.WithField("trace", string(debug.Stack())).Error("out Header ", &Header{Version, t, st, 0, hostinfo.remoteIndexId, c}, p)
 	out = header.Encode(out, header.Version, t, st, hostinfo.remoteIndexId, c)
-	f.connectionManager.Out(hostinfo)
-
-	// Query our LH if we haven't since the last time we've been rebound, this will cause the remote to punch against
-	// all our addrs and enable a faster roaming.
-	if t != header.CloseTunnel && hostinfo.lastRebindCount != f.rebindCount {
-		//NOTE: there is an update hole if a tunnel isn't used and exactly 256 rebinds occur before the tunnel is
-		// finally used again. This tunnel would eventually be torn down and recreated if this action didn't help.
+	// A closing tunnel is torn down right after this, so skip the connection manager entirely: no point recording
+	// traffic or asking the lighthouse for a punch. Otherwise, if we rebound since this tunnel last sent, ask the
+	// lighthouse to get the far side punching at us again.
+	if t != header.CloseTunnel && f.connectionManager.Out(hostinfo) {
 		f.lightHouse.QueryServer(hostinfo.vpnAddrs[0])
-		hostinfo.lastRebindCount = f.rebindCount
 		if f.l.Enabled(context.Background(), slog.LevelDebug) {
-			f.l.Debug("Lighthouse update triggered for punch due to rebind counter",
+			f.l.Debug("Lighthouse update triggered for punch due to rebind epoch",
 				"vpnAddrs", hostinfo.vpnAddrs,
 			)
 		}