routing table refactor

main.go

@@ -129,6 +129,12 @@ func main() {
 		}()
 	}
 
+	// ----------------------------- Routing table ----------------------------
+	routing := &routingTable{
+		table:     make(map[ddp.Network][]*route),
+		allRoutes: make(map[*route]struct{}),
+	}
+
 	// ------------------------- Configured peer setup ------------------------
 	for _, peerStr := range cfg.Peers {
 		if !hasPortRE.MatchString(peerStr) {
@@ -148,9 +154,10 @@ func main() {
 				RemoteDI:    aurp.IPDomainIdentifier(raddr.IP),
 				LocalConnID: nextConnID,
 			},
-			conn:  ln,
-			raddr: raddr,
-			recv:  make(chan aurp.Packet, 1024),
+			conn:         ln,
+			raddr:        raddr,
+			recv:         make(chan aurp.Packet, 1024),
+			routingTable: routing,
 		}
 		aurp.Inc(&nextConnID)
 		peers[udpAddrFromNet(raddr)] = peer
@@ -164,9 +171,10 @@ func main() {
 
 	// --------------------------------- RTMP ---------------------------------
 	rtmpMachine := &RTMPMachine{
-		aarp:       aarpMachine,
-		cfg:        cfg,
-		pcapHandle: pcapHandle,
+		aarp:         aarpMachine,
+		cfg:          cfg,
+		pcapHandle:   pcapHandle,
+		routingTable: routing,
 	}
 	rtmpCh := make(chan *ddp.ExtPacket, 1024)
 	go rtmpMachine.Run(ctx, rtmpCh)
@@ -241,7 +249,7 @@ func main() {
 				// addressed to a node on the local network."
 				if ddpkt.DstNet != 0 && (ddpkt.DstNet < cfg.EtherTalk.NetStart || ddpkt.DstNet > cfg.EtherTalk.NetEnd) {
 					// Is it for a network in the routing table?
-					rt := lookupRoute(ddpkt.DstNet)
+					rt := routing.lookupRoute(ddpkt.DstNet)
 					if rt == nil {
 						log.Printf("DDP: no route for network %d", ddpkt.DstNet)
 						continue
@@ -481,9 +489,10 @@ func main() {
 					RemoteDI:    dh.SourceDI, // platinum rule
 					LocalConnID: nextConnID,
 				},
-				conn:  ln,
-				raddr: raddr,
-				recv:  make(chan aurp.Packet, 1024),
+				conn:         ln,
+				raddr:        raddr,
+				recv:         make(chan aurp.Packet, 1024),
+				routingTable: routing,
 			}
 			aurp.Inc(&nextConnID)
 			peers[ra] = pr

peer.go

@@ -81,6 +81,8 @@ type peer struct {
 	conn  *net.UDPConn
 	raddr *net.UDPAddr
 	recv  chan aurp.Packet
+
+	routingTable *routingTable
 }
 
 // send encodes and sends pkt to the remote host.
@@ -277,7 +279,7 @@ func (p *peer) handle(ctx context.Context) error {
 				log.Printf("Learned about these networks: %v", pkt.Networks)
 
 				for _, nt := range pkt.Networks {
-					upsertRoutes(
+					p.routingTable.upsertRoutes(
 						nt.Extended,
 						ddp.Network(nt.RangeStart),
 						ddp.Network(nt.RangeEnd),

route.go

@@ -10,6 +10,8 @@ import (
 	"github.com/sfiera/multitalk/pkg/ddp"
 )
 
+const maxRouteAge = 10 * time.Minute // TODO: confirm
+
 type route struct {
 	extended bool
 	netStart ddp.Network
@@ -19,29 +21,32 @@ type route struct {
 	last     time.Time
 }
 
-var (
-	routingTableMu sync.Mutex
-	routingTable   = make(map[ddp.Network][]*route)
+type routingTable struct {
+	tableMu sync.Mutex
+	table   map[ddp.Network][]*route
 
 	allRoutesMu sync.Mutex
-	allRoutes   = make(map[*route]struct{})
-)
-
-func lookupRoute(network ddp.Network) *route {
-	routingTableMu.Lock()
-	defer routingTableMu.Unlock()
-
-	rs := routingTable[network]
-	if len(rs) == 0 {
-		return nil
-	}
-	return rs[0]
+	allRoutes   map[*route]struct{}
 }
 
-func upsertRoutes(extended bool, netStart, netEnd ddp.Network, peer *peer, metric uint8) error {
+func (rt *routingTable) lookupRoute(network ddp.Network) *route {
+	rt.tableMu.Lock()
+	defer rt.tableMu.Unlock()
+
+	for _, rs := range rt.table[network] {
+		if time.Since(rs.last) > maxRouteAge {
+			continue
+		}
+		return rs
+	}
+	return nil
+}
+
+func (rt *routingTable) upsertRoutes(extended bool, netStart, netEnd ddp.Network, peer *peer, metric uint8) error {
 	if netStart > netEnd {
 		return fmt.Errorf("invalid network range [%d, %d]", netStart, netEnd)
 	}
+
 	r := &route{
 		extended: extended,
 		netStart: netStart,
@@ -51,17 +56,33 @@ func upsertRoutes(extended bool, netStart, netEnd ddp.Network, peer *peer, metri
 		last:     time.Now(),
 	}
 
-	allRoutesMu.Lock()
-	allRoutes[r] = struct{}{}
-	allRoutesMu.Unlock()
+	rt.allRoutesMu.Lock()
+	rt.allRoutes[r] = struct{}{}
+	rt.allRoutesMu.Unlock()
 
-	routingTableMu.Lock()
-	defer routingTableMu.Unlock()
+	rt.tableMu.Lock()
+	defer rt.tableMu.Unlock()
 	for n := netStart; n <= netEnd; n++ {
-		routingTable[n] = append(routingTable[n], r)
-		slices.SortFunc(routingTable[n], func(r, s *route) int {
+		rt.table[n] = append(rt.table[n], r)
+		slices.SortFunc(rt.table[n], func(r, s *route) int {
 			return cmp.Compare(r.metric, s.metric)
 		})
 	}
 	return nil
 }
+
+func (rt *routingTable) validRoutes() []*route {
+	rt.allRoutesMu.Lock()
+	defer rt.allRoutesMu.Unlock()
+	valid := make([]*route, 0, len(rt.allRoutes))
+	for r := range rt.allRoutes {
+		if r.peer == nil {
+			continue
+		}
+		if time.Since(r.last) > maxRouteAge {
+			continue
+		}
+		valid = append(valid, r)
+	}
+	return r
+}

rtmp.go

@@ -32,9 +32,10 @@ import (
 
 // RTMPMachine implements RTMP on an AppleTalk network attached to the router.
 type RTMPMachine struct {
-	aarp       *AARPMachine
-	cfg        *config
-	pcapHandle *pcap.Handle
+	aarp         *AARPMachine
+	cfg          *config
+	pcapHandle   *pcap.Handle
+	routingTable *routingTable
 }
 
 // Run executes the machine.
@@ -213,12 +214,7 @@ func (m *RTMPMachine) dataPacket(myAddr ddp.Addr) *rtmp.DataPacket {
 			},
 		},
 	}
-	allRoutesMu.Lock()
-	defer allRoutesMu.Unlock()
-	for rt := range allRoutes {
-		if rt.peer == nil {
-			continue
-		}
+	for _, rt := range m.routingTable.validRoutes() {
 		p.NetworkTuples = append(p.NetworkTuples, rtmp.NetworkTuple{
 			Extended:   rt.extended,
 			RangeStart: rt.netStart,