wip

node/globalfuncs.go

@@ -0,0 +1,79 @@
+package node
+
+import (
+	"log"
+	"sync/atomic"
+)
+
+func _sendControlPacket(
+	pkt interface{ Marshal([]byte) []byte },
+	route peerRoute,
+	buf1 []byte,
+	buf2 []byte,
+) {
+	buf := pkt.Marshal(buf1)
+	h1 := header{
+		StreamID: controlStreamID,
+		Counter:  atomic.AddUint64(&sendCounters[route.IP], 1),
+		SourceIP: localIP,
+		DestIP:   route.IP,
+	}
+	buf = route.ControlCipher.Encrypt(h1, buf, buf2)
+
+	if route.RelayIP == 0 {
+		_conn.WriteTo(buf, route.RemoteAddr)
+		return
+	}
+
+	relayRoute := routingTable[route.RelayIP].Load()
+	if !relayRoute.Up || !relayRoute.Relay {
+		log.Print("Failed to send control packet: relay not available.")
+		return
+	}
+
+	h2 := header{
+		StreamID: dataStreamID,
+		Counter:  atomic.AddUint64(&sendCounters[relayRoute.IP], 1),
+		SourceIP: localIP,
+		DestIP:   route.IP,
+	}
+	buf = relayRoute.DataCipher.Encrypt(h2, buf, buf1)
+	_conn.WriteTo(buf, relayRoute.RemoteAddr)
+}
+
+func _sendDataPacket(
+	pkt []byte,
+	route *peerRoute,
+	buf1 []byte,
+	buf2 []byte,
+) {
+	h := header{
+		StreamID: dataStreamID,
+		Counter:  atomic.AddUint64(&sendCounters[route.IP], 1),
+		SourceIP: localIP,
+		DestIP:   route.IP,
+	}
+
+	enc := route.DataCipher.Encrypt(h, pkt, buf1)
+
+	if route.RelayIP == 0 {
+		_conn.WriteTo(enc, route.RemoteAddr)
+		return
+	}
+
+	relayRoute := routingTable[route.RelayIP].Load()
+	if !relayRoute.Up || !relayRoute.Relay {
+		log.Print("Failed to send data packet: relay not available.")
+		return
+	}
+
+	h2 := header{
+		StreamID: dataStreamID,
+		Counter:  atomic.AddUint64(&sendCounters[relayRoute.IP], 1),
+		SourceIP: localIP,
+		DestIP:   route.IP,
+	}
+
+	enc = relayRoute.DataCipher.Encrypt(h2, enc, buf2)
+	_conn.WriteTo(enc, relayRoute.RemoteAddr)
+}

node/globals.go

@@ -1,15 +1,57 @@
 package node
 
-import "net/netip"
+import (
+	"net/netip"
+	"sync/atomic"
+	"vppn/m"
+)
+
+var zeroAddrPort = netip.AddrPort{}
 
 const (
 	bufferSize            = 1536
-	if_mtu                = 1400
+	if_mtu                = 1200
 	if_queue_len          = 2048
 	controlCipherOverhead = 16
 	dataCipherOverhead    = 16
 )
 
+type peerRoute struct {
+	IP            byte
+	Up            bool // True if data can be sent on the route.
+	Relay         bool // True if the peer is a relay.
+	ControlCipher *controlCipher
+	DataCipher    *dataCipher
+	RemoteAddr    netip.AddrPort // Remote address if directly connected.
+	LocalAddr     netip.AddrPort // Local address as seen by the remote.
+	RelayIP       byte           // Non-zero if we should relay.
+}
+
+// Configuration for this peer.
 var (
-	zeroAddrPort = netip.AddrPort{}
+	netName    string
+	localIP    byte
+	localPub   bool
+	privateKey []byte
 )
+
+// Shared interface for writing.
+var _iface *ifWriter
+
+// Shared connection for writing.
+var _conn *connWriter
+
+// Counters for sending to each peer.
+var sendCounters [256]uint64
+
+// Duplicate checkers for incoming packets.
+var dupChecks [256]*dupCheck
+
+// Channels for incoming control packets.
+var controlPackets [256]chan controlPacket
+
+// Channels for incoming peer updates from the hub.
+var peerUpdates [256]chan *m.Peer
+
+// Global routing table.
+var routingTable [256]*atomic.Pointer[peerRoute]

node/header.go

@@ -10,7 +10,6 @@ const (
 	controlHeaderSize = 24
 	dataStreamID      = 1
 	dataHeaderSize    = 12
-	relayStreamID     = 3
 )
 
 type header struct {

node/main.go

@@ -11,6 +11,8 @@ import (
 	"net/netip"
 	"os"
 	"runtime/debug"
+	"sync/atomic"
+	"time"
 	"vppn/m"
 )
 
@@ -24,7 +26,6 @@ func Main() {
 	defer panicHandler()
 
 	var (
-		netName  string
 		initURL  string
 		listenIP string
 		port     int
@@ -42,14 +43,14 @@ func Main() {
 	}
 
 	if initURL != "" {
-		mainInit(netName, initURL)
+		mainInit(initURL)
 		return
 	}
 
-	main(netName, listenIP, uint16(port))
+	main(listenIP, uint16(port))
 }
 
-func mainInit(netName, initURL string) {
+func mainInit(initURL string) {
 	if _, err := loadPeerConfig(netName); err == nil {
 		log.Fatalf("Network is already initialized.")
 	}
@@ -79,15 +80,15 @@ func mainInit(netName, initURL string) {
 
 // ----------------------------------------------------------------------------
 
-func main(netName, listenIP string, port uint16) {
+func main(listenIP string, port uint16) {
-	conf, err := loadPeerConfig(netName)
+	config, err := loadPeerConfig(netName)
 	if err != nil {
 		log.Fatalf("Failed to load configuration: %v", err)
 	}
 
-	port = determinePort(conf.Port, port)
+	port = determinePort(config.Port, port)
 
-	iface, err := openInterface(conf.Network, conf.PeerIP, netName)
+	iface, err := openInterface(config.Network, config.PeerIP, netName)
 	if err != nil {
 		log.Fatalf("Failed to open interface: %v", err)
 	}
@@ -102,18 +103,34 @@ func main(netName, listenIP string, port uint16) {
 		log.Fatalf("Failed to open UDP port: %v", err)
 	}
 
-	connWriter := newConnWriter(conn)
+	// Intialize globals.
-	ifWriter := newIFWriter(iface)
+	localIP = config.PeerIP
+	localPub = addrIsValid(config.PublicIP)
+	privateKey = config.EncPrivKey
 
-	peers := remotePeers{}
+	_iface = newIFWriter(iface)
+	_conn = newConnWriter(conn)
 
-	for i := range peers {
+	for i := range 256 {
-		peers[i] = newRemotePeer(conf, byte(i), ifWriter, connWriter, &peers)
+		sendCounters[i] = uint64(time.Now().Unix()<<30) + 1
+		dupChecks[i] = newDupCheck(0)
+		controlPackets[i] = make(chan controlPacket, 256)
+		peerUpdates[i] = make(chan *m.Peer)
+		routingTable[i] = &atomic.Pointer[peerRoute]{}
+		route := peerRoute{IP: byte(i)}
+		routingTable[i].Store(&route)
 	}
 
-	go newHubPoller(netName, conf, peers).Run()
+	// Start supervisors.
-	go readFromConn(conn, peers)
+	for i := range 256 {
-	readFromIFace(iface, peers)
+		go newPeerSupervisor(i).Run()
+	}
+
+	// --------------------
+
+	go newHubPoller(config).Run()
+	go readFromConn(conn)
+	readFromIFace(iface)
 }
 
 // ----------------------------------------------------------------------------
@@ -130,7 +147,7 @@ func determinePort(confPort, portFromCommandLine uint16) uint16 {
 
 // ----------------------------------------------------------------------------
 
-func readFromConn(conn *net.UDPConn, peers remotePeers) {
+func readFromConn(conn *net.UDPConn) {
 
 	defer panicHandler()
 
@@ -139,6 +156,7 @@ func readFromConn(conn *net.UDPConn, peers remotePeers) {
 		n          int
 		err        error
 		buf        = make([]byte, bufferSize)
+		decBuf     = make([]byte, bufferSize)
 		data       []byte
 		h          header
 	)
@@ -156,27 +174,119 @@ func readFromConn(conn *net.UDPConn, peers remotePeers) {
 		}
 
 		h.Parse(data)
-		peers[h.SourceIP].HandlePacket(remoteAddr, h, data)
+		switch h.StreamID {
+		case controlStreamID:
+			handleControlPacket(remoteAddr, h, data, decBuf)
+
+		case dataStreamID:
+			handleDataPacket(h, data, decBuf)
+
+		default:
+			log.Printf("Unknown stream ID: %d", h.StreamID)
 		}
+	}
+}
+
+func handleControlPacket(addr netip.AddrPort, h header, data, decBuf []byte) {
+	route := routingTable[h.SourceIP].Load()
+	if route.ControlCipher == nil {
+		log.Printf("Not connected (control).")
+		return
+	}
+
+	if h.DestIP != localIP {
+		log.Printf("Incorrect destination IP on control packet: %d != %d", h.DestIP, localIP)
+		return
+	}
+
+	out, ok := route.ControlCipher.Decrypt(data, decBuf)
+	if !ok {
+		log.Printf("Failed to decrypt control packet.")
+		return
+	}
+
+	if len(out) == 0 {
+		log.Printf("Empty control packet from: %d", h.SourceIP)
+		return
+	}
+
+	if dupChecks[h.SourceIP].IsDup(h.Counter) {
+		log.Printf("[%03d] Duplicate control packet: %d", h.SourceIP, h.Counter)
+		return
+	}
+
+	pkt := controlPacket{
+		SrcIP:      h.SourceIP,
+		RemoteAddr: addr,
+	}
+
+	if err := pkt.ParsePayload(out); err != nil {
+		log.Printf("Failed to parse control packet: %v", err)
+		return
+	}
+
+	select {
+	case controlPackets[h.SourceIP] <- pkt:
+	default:
+		log.Printf("Dropping control packet.")
+	}
+}
+
+func handleDataPacket(h header, data []byte, decBuf []byte) {
+	route := routingTable[h.SourceIP].Load()
+	if !route.Up {
+		log.Printf("Not connected (recv).")
+		return
+	}
+
+	dec, ok := route.DataCipher.Decrypt(data, decBuf)
+	if !ok {
+		log.Printf("Failed to decrypt data packet.")
+		return
+	}
+
+	if dupChecks[h.SourceIP].IsDup(h.Counter) {
+		log.Printf("[%03d] Duplicate data packet: %d", h.SourceIP, h.Counter)
+		return
+	}
+
+	if h.DestIP == localIP {
+		_iface.Write(dec)
+		return
+	}
+
+	destRoute := routingTable[h.DestIP].Load()
+	if !destRoute.Up || destRoute.RelayIP != 0 {
+		log.Printf("Not connected (relay)")
+		return
+	}
+
+	_conn.WriteTo(dec, destRoute.RemoteAddr)
 }
 
 // ----------------------------------------------------------------------------
 
-func readFromIFace(iface io.ReadWriteCloser, peers remotePeers) {
+func readFromIFace(iface io.ReadWriteCloser) {
-
 	var (
-		buf      = make([]byte, bufferSize)
+		packet   = make([]byte, bufferSize)
-		packet   []byte
+		buf1     = make([]byte, bufferSize)
+		buf2     = make([]byte, bufferSize)
 		remoteIP byte
 		err      error
 	)
 
 	for {
-		packet, remoteIP, err = readNextPacket(iface, buf)
+		packet, remoteIP, err = readNextPacket(iface, packet)
 		if err != nil {
 			log.Fatalf("Failed to read from interface: %v", err)
 		}
 
-		peers[remoteIP].HandleInterfacePacket(packet)
+		route := routingTable[remoteIP].Load()
+		if !route.Up {
+			log.Printf("Route not connected: %d", remoteIP)
+			continue
+		}
+
+		_sendDataPacket(packet, route, buf1, buf2)
 	}
 }

node/peer-pollhub.go

@@ -11,14 +11,12 @@ import (
 )
 
 type hubPoller struct {
-	netName string
-	localIP byte
 	client   *http.Client
 	req      *http.Request
-	peers   remotePeers
+	versions [256]int64
 }
 
-func newHubPoller(netName string, conf m.PeerConfig, peers remotePeers) *hubPoller {
+func newHubPoller(conf m.PeerConfig) *hubPoller {
 	u, err := url.Parse(conf.HubAddress)
 	if err != nil {
 		log.Fatalf("Failed to parse hub address %s: %v", conf.HubAddress, err)
@@ -35,18 +33,15 @@ func newHubPoller(netName string, conf m.PeerConfig, peers remotePeers) *hubPoll
 	req.SetBasicAuth("", conf.APIKey)
 
 	return &hubPoller{
-		netName: netName,
-		localIP: conf.PeerIP,
 		client: client,
 		req:    req,
-		peers:   peers,
 	}
 }
 
 func (hp *hubPoller) Run() {
 	defer panicHandler()
 
-	state, err := loadNetworkState(hp.netName)
+	state, err := loadNetworkState(netName)
 	if err != nil {
 		log.Printf("Failed to load network state: %v", err)
 		log.Printf("Polling hub...")
@@ -83,15 +78,18 @@ func (hp *hubPoller) pollHub() {
 
 	hp.applyNetworkState(state)
 
-	if err := storeNetworkState(hp.netName, state); err != nil {
+	if err := storeNetworkState(netName, state); err != nil {
 		log.Printf("Failed to store network state: %v", err)
 	}
 }
 
 func (hp *hubPoller) applyNetworkState(state m.NetworkState) {
-	for i := range state.Peers {
+	for i, peer := range state.Peers {
-		if i != int(hp.localIP) {
+		if i != int(localIP) {
-			hp.peers[i].HandlePeerUpdate(state.Peers[i])
+			if peer != nil && peer.Version != hp.versions[i] {
+				peerUpdates[i] <- state.Peers[i]
+				hp.versions[i] = peer.Version
+			}
 		}
 	}
 }

node/peer-super-states.go

@@ -1,280 +0,0 @@
-package node
-
-import (
-	"math/rand"
-	"net/netip"
-	"time"
-	"vppn/m"
-)
-
-// ----------------------------------------------------------------------------
-
-func (s *peerSuper) noPeer() stateFunc {
-	return s.peerUpdate(<-s.peerUpdates)
-}
-
-// ----------------------------------------------------------------------------
-
-func (s *peerSuper) peerUpdate(peer *m.Peer) stateFunc {
-	return func() stateFunc { return s._peerUpdate(peer) }
-}
-
-func (s *peerSuper) _peerUpdate(peer *m.Peer) stateFunc {
-	defer s.publish()
-
-	s.peer = peer
-	s.staged = peerRouteInfo{}
-
-	if s.peer == nil {
-		return s.noPeer
-	}
-
-	s.staged.controlCipher = newControlCipher(s.privKey, peer.EncPubKey)
-	s.staged.dataCipher = newDataCipher()
-
-	if ip, isValid := netip.AddrFromSlice(peer.PublicIP); isValid {
-		s.remotePub = true
-		s.staged.relay = peer.Mediator
-		s.staged.remoteAddr = netip.AddrPortFrom(ip, peer.Port)
-	}
-
-	if s.remotePub == s.localPub {
-		if s.localIP < s.remoteIP {
-			return s.serverAccept
-		}
-		return s.clientInit
-	}
-
-	if s.remotePub {
-		return s.clientInit
-	}
-	return s.serverAccept
-}
-
-// ----------------------------------------------------------------------------
-
-func (s *peerSuper) serverAccept() stateFunc {
-	s.logf("STATE: server-accept")
-	s.staged.up = false
-	s.staged.dataCipher = nil
-	s.staged.remoteAddr = zeroAddrPort
-	s.staged.relayIP = 0
-	s.publish()
-
-	var syn synPacket
-
-	for {
-		select {
-		case peer := <-s.peerUpdates:
-			return s.peerUpdate(peer)
-
-		case pkt := <-s.controlPackets:
-			switch p := pkt.Payload.(type) {
-
-			case synPacket:
-				syn = p
-				s.staged.remoteAddr = pkt.RemoteAddr
-				s.staged.dataCipher = newDataCipherFromKey(syn.SharedKey)
-				s.staged.relayIP = syn.RelayIP
-				s.publish()
-				s.sendControlPacket(synAckPacket{
-					TraceID:  syn.TraceID,
-					RecvAddr: pkt.RemoteAddr,
-				})
-
-			case ackPacket:
-				if p.TraceID != syn.TraceID {
-					continue
-				}
-
-				// Publish.
-				return s.serverConnected(syn.TraceID)
-			}
-		}
-	}
-}
-
-// ----------------------------------------------------------------------------
-
-func (s *peerSuper) serverConnected(traceID uint64) stateFunc {
-	s.logf("STATE: server-connected")
-	s.staged.up = true
-	s.publish()
-	return func() stateFunc {
-		return s._serverConnected(traceID)
-	}
-}
-
-func (s *peerSuper) _serverConnected(traceID uint64) stateFunc {
-
-	timeoutTimer := time.NewTimer(timeoutInterval)
-	defer timeoutTimer.Stop()
-
-	for {
-		select {
-		case peer := <-s.peerUpdates:
-			return s.peerUpdate(peer)
-
-		case pkt := <-s.controlPackets:
-			switch p := pkt.Payload.(type) {
-
-			case ackPacket:
-				if p.TraceID != traceID {
-					return s.serverAccept
-				}
-
-				s.sendControlPacket(ackPacket{TraceID: traceID, RecvAddr: pkt.RemoteAddr})
-				timeoutTimer.Reset(timeoutInterval)
-			}
-
-		case <-timeoutTimer.C:
-			s.logf("server timeout")
-			return s.serverAccept
-		}
-	}
-}
-
-// ----------------------------------------------------------------------------
-
-func (s *peerSuper) clientInit() stateFunc {
-	s.logf("STATE: client-init")
-	if !s.remotePub {
-		// TODO: Check local discovery for IP.
-		// TODO: Attempt UDP hole punch.
-		// TODO: client-relayed
-		return s.clientSelectRelay
-	}
-
-	return s.clientDial
-}
-
-// ----------------------------------------------------------------------------
-
-func (s *peerSuper) clientSelectRelay() stateFunc {
-	s.logf("STATE: client-select-relay")
-
-	timer := time.NewTimer(0)
-	defer timer.Stop()
-
-	for {
-		select {
-		case peer := <-s.peerUpdates:
-			return s.peerUpdate(peer)
-
-		case <-timer.C:
-			ip := s.selectRelayIP()
-			if ip != 0 {
-				s.logf("Got relay: %d", ip)
-				s.staged.relayIP = ip
-				s.publish()
-				return s.clientDial
-			}
-
-			s.logf("No relay available.")
-			timer.Reset(pingInterval)
-		}
-	}
-}
-
-func (s *peerSuper) selectRelayIP() byte {
-	possible := make([]byte, 0, 8)
-	for i, peer := range s.peers {
-		if peer.CanRelay() {
-			possible = append(possible, byte(i))
-		}
-	}
-
-	if len(possible) == 0 {
-		return 0
-	}
-	return possible[rand.Intn(len(possible))]
-}
-
-// ----------------------------------------------------------------------------
-
-func (s *peerSuper) clientDial() stateFunc {
-	s.logf("STATE: client-dial")
-
-	var (
-		syn = synPacket{
-			TraceID:   newTraceID(),
-			SharedKey: s.staged.dataCipher.Key(),
-			RelayIP:   s.staged.relayIP,
-		}
-
-		timeout = time.NewTimer(dialTimeout)
-	)
-
-	defer timeout.Stop()
-
-	s.sendControlPacket(syn)
-
-	for {
-		select {
-
-		case peer := <-s.peerUpdates:
-			return s.peerUpdate(peer)
-
-		case pkt := <-s.controlPackets:
-			switch p := pkt.Payload.(type) {
-			case synAckPacket:
-				if p.TraceID != syn.TraceID {
-					continue // Hmm...
-				}
-				s.sendControlPacket(ackPacket{TraceID: syn.TraceID, RecvAddr: pkt.RemoteAddr})
-				return s.clientConnected(p)
-			}
-
-		case <-timeout.C:
-			return s.clientInit
-		}
-	}
-}
-
-// ----------------------------------------------------------------------------
-
-func (s *peerSuper) clientConnected(p synAckPacket) stateFunc {
-	s.logf("STATE: client-connected")
-	s.staged.up = true
-	s.staged.localAddr = p.RecvAddr
-	s.publish()
-
-	return func() stateFunc {
-		return s._clientConnected(p.TraceID)
-	}
-}
-
-func (s *peerSuper) _clientConnected(traceID uint64) stateFunc {
-
-	pingTimer := time.NewTimer(pingInterval)
-	timeoutTimer := time.NewTimer(timeoutInterval)
-
-	defer pingTimer.Stop()
-	defer timeoutTimer.Stop()
-
-	for {
-		select {
-		case peer := <-s.peerUpdates:
-			return s.peerUpdate(peer)
-
-		case pkt := <-s.controlPackets:
-			switch p := pkt.Payload.(type) {
-
-			case ackPacket:
-				if p.TraceID != traceID {
-					return s.clientInit
-				}
-				timeoutTimer.Reset(timeoutInterval)
-			}
-
-		case <-pingTimer.C:
-			s.sendControlPacket(ackPacket{TraceID: traceID})
-			pingTimer.Reset(pingInterval)
-
-		case <-timeoutTimer.C:
-			s.logf("client timeout")
-			return s.clientInit
-
-		}
-	}
-}

node/peer-super.go

@@ -1,95 +0,0 @@
-package node
-
-import (
-	"fmt"
-	"log"
-	"sync/atomic"
-	"vppn/m"
-)
-
-type peerSuper struct {
-	// The purpose of this state machine is to manage this published data.
-	published *atomic.Pointer[peerRouteInfo]
-	staged    peerRouteInfo // Local copy of shared data. See publish().
-
-	// The other remote peers.
-	peers *remotePeers
-
-	// Immutable data.
-	localIP  byte
-	localPub bool
-	remoteIP byte
-	privKey  []byte
-	conn     *connWriter
-
-	// For sending to peer.
-	counter *uint64
-
-	// Mutable peer data.
-	peer      *m.Peer
-	remotePub bool
-
-	// Incoming events.
-	peerUpdates    chan *m.Peer
-	controlPackets chan controlPacket
-
-	// Buffers
-	buf    []byte
-	encBuf []byte
-}
-
-type stateFunc func() stateFunc
-
-func (s *peerSuper) Run() {
-	state := s.noPeer
-	for {
-		state = state()
-	}
-}
-
-// ----------------------------------------------------------------------------
-
-func (s *peerSuper) logf(msg string, args ...any) {
-	log.Printf(fmt.Sprintf("[%03d] ", s.remoteIP)+msg, args...)
-}
-
-// ----------------------------------------------------------------------------
-
-func (s *peerSuper) publish() {
-	data := s.staged
-	s.published.Store(&data)
-}
-
-// ----------------------------------------------------------------------------
-
-func (s *peerSuper) sendControlPacket(pkt interface{ Marshal([]byte) []byte }) {
-	buf := pkt.Marshal(s.buf)
-	h := header{
-		StreamID: controlStreamID,
-		Counter:  atomic.AddUint64(s.counter, 1),
-		SourceIP: s.localIP,
-		DestIP:   s.remoteIP,
-	}
-
-	buf = s.staged.controlCipher.Encrypt(h, buf, s.encBuf)
-	if s.staged.relayIP != 0 {
-		s.peers[s.staged.relayIP].RelayTo(s.remoteIP, buf)
-	} else {
-		s.conn.WriteTo(buf, s.staged.remoteAddr)
-	}
-}
-
-// ----------------------------------------------------------------------------
-
-func (s *peerSuper) sendControlPacketDirect(pkt interface{ Marshal([]byte) []byte }) {
-	buf := pkt.Marshal(s.buf)
-	h := header{
-		StreamID: controlStreamID,
-		Counter:  atomic.AddUint64(s.counter, 1),
-		SourceIP: s.localIP,
-		DestIP:   s.remoteIP,
-	}
-
-	buf = s.staged.controlCipher.Encrypt(h, buf, s.encBuf)
-	s.conn.WriteTo(buf, s.staged.remoteAddr)
-}

node/peer-supervisor.go

@@ -1,6 +1,11 @@
 package node
 
 import (
+	"fmt"
+	"log"
+	"math/rand"
+	"net/netip"
+	"sync/atomic"
 	"time"
 	"vppn/m"
 )
@@ -12,23 +17,336 @@ const (
 	timeoutInterval = 20 * time.Second
 )
 
-func (rp *remotePeer) supervise(conf m.PeerConfig) {
+// ----------------------------------------------------------------------------
-	defer panicHandler()
 
-	super := &peerSuper{
+type peerSupervisor struct {
-		published:      rp.route,
+	// The purpose of this state machine is to manage this published data.
-		peers:          rp.peers,
+	published *atomic.Pointer[peerRoute]
-		localIP:        rp.localIP,
+	staged    peerRoute // Local copy of shared data. See publish().
-		localPub:       addrIsValid(conf.PublicIP),
+
-		remoteIP:       rp.remoteIP,
+	// Immutable data.
-		privKey:        conf.EncPrivKey,
+	remoteIP byte // Remote VPN IP.
-		conn:           rp.conn,
+
-		counter:        &rp.counter,
+	// Mutable peer data.
-		peerUpdates:    rp.peerUpdates,
+	peer      *m.Peer
-		controlPackets: rp.controlPackets,
+	remotePub bool
-		buf:            make([]byte, bufferSize),
+
-		encBuf:         make([]byte, bufferSize),
+	// Incoming events.
+	peerUpdates    chan *m.Peer
+	controlPackets chan controlPacket
+
+	// Buffers for sending control packets.
+	buf1 []byte
+	buf2 []byte
+}
+
+func newPeerSupervisor(i int) *peerSupervisor {
+	return &peerSupervisor{
+		published:      routingTable[i],
+		remoteIP:       byte(i),
+		peerUpdates:    peerUpdates[i],
+		controlPackets: controlPackets[i],
+		buf1:           make([]byte, bufferSize),
+		buf2:           make([]byte, bufferSize),
+	}
+}
+
+type stateFunc func() stateFunc
+
+func (s *peerSupervisor) Run() {
+	state := s.noPeer
+	for {
+		state = state()
+	}
+}
+
+// ----------------------------------------------------------------------------
+
+func (s *peerSupervisor) sendControlPacket(pkt interface{ Marshal([]byte) []byte }) {
+	_sendControlPacket(pkt, s.staged, s.buf1, s.buf2)
+}
+
+// ----------------------------------------------------------------------------
+
+func (s *peerSupervisor) logf(msg string, args ...any) {
+	log.Printf(fmt.Sprintf("[%03d] ", s.remoteIP)+msg, args...)
+}
+
+// ----------------------------------------------------------------------------
+
+func (s *peerSupervisor) publish() {
+	data := s.staged
+	s.published.Store(&data)
+}
+
+// ----------------------------------------------------------------------------
+
+func (s *peerSupervisor) noPeer() stateFunc {
+	return s.peerUpdate(<-s.peerUpdates)
+}
+
+// ----------------------------------------------------------------------------
+
+func (s *peerSupervisor) peerUpdate(peer *m.Peer) stateFunc {
+	return func() stateFunc { return s._peerUpdate(peer) }
+}
+
+func (s *peerSupervisor) _peerUpdate(peer *m.Peer) stateFunc {
+	defer s.publish()
+
+	s.peer = peer
+	s.staged = peerRoute{}
+
+	if s.peer == nil {
+		return s.noPeer
 	}
 
-	go super.Run()
+	s.staged.IP = s.remoteIP
+	s.staged.ControlCipher = newControlCipher(privateKey, peer.EncPubKey)
+	s.staged.DataCipher = newDataCipher()
+
+	if ip, isValid := netip.AddrFromSlice(peer.PublicIP); isValid {
+		s.remotePub = true
+		s.staged.Relay = peer.Mediator
+		s.staged.RemoteAddr = netip.AddrPortFrom(ip, peer.Port)
+	}
+
+	if s.remotePub == localPub {
+		if localIP < s.remoteIP {
+			return s.serverAccept
+		}
+		return s.clientInit
+	}
+
+	if s.remotePub {
+		return s.clientInit
+	}
+	return s.serverAccept
+}
+
+// ----------------------------------------------------------------------------
+
+func (s *peerSupervisor) serverAccept() stateFunc {
+	s.logf("STATE: server-accept")
+	s.staged.Up = false
+	s.staged.DataCipher = nil
+	s.staged.RemoteAddr = zeroAddrPort
+	s.staged.RelayIP = 0
+	s.publish()
+
+	var syn synPacket
+
+	for {
+		select {
+		case peer := <-s.peerUpdates:
+			return s.peerUpdate(peer)
+
+		case pkt := <-s.controlPackets:
+			switch p := pkt.Payload.(type) {
+
+			case synPacket:
+				syn = p
+				s.staged.RemoteAddr = pkt.RemoteAddr
+				s.staged.DataCipher = newDataCipherFromKey(syn.SharedKey)
+				s.staged.RelayIP = syn.RelayIP
+				s.publish()
+				s.sendControlPacket(synAckPacket{TraceID: syn.TraceID, RecvAddr: pkt.RemoteAddr})
+
+			case ackPacket:
+				if p.TraceID != syn.TraceID {
+					continue
+				}
+
+				// Publish.
+				return s.serverConnected(syn.TraceID)
+			}
+		}
+	}
+}
+
+// ----------------------------------------------------------------------------
+
+func (s *peerSupervisor) serverConnected(traceID uint64) stateFunc {
+	s.logf("STATE: server-connected")
+	s.staged.Up = true
+	s.publish()
+	return func() stateFunc {
+		return s._serverConnected(traceID)
+	}
+}
+
+func (s *peerSupervisor) _serverConnected(traceID uint64) stateFunc {
+
+	timeoutTimer := time.NewTimer(timeoutInterval)
+	defer timeoutTimer.Stop()
+
+	for {
+		select {
+		case peer := <-s.peerUpdates:
+			return s.peerUpdate(peer)
+
+		case pkt := <-s.controlPackets:
+			switch p := pkt.Payload.(type) {
+
+			case ackPacket:
+				if p.TraceID != traceID {
+					return s.serverAccept
+				}
+				s.sendControlPacket(ackPacket{TraceID: traceID, RecvAddr: pkt.RemoteAddr})
+				timeoutTimer.Reset(timeoutInterval)
+			}
+
+		case <-timeoutTimer.C:
+			s.logf("server timeout")
+			return s.serverAccept
+		}
+	}
+}
+
+// ----------------------------------------------------------------------------
+
+func (s *peerSupervisor) clientInit() stateFunc {
+	s.logf("STATE: client-init")
+	if !s.remotePub {
+		// TODO: Check local discovery for IP.
+		// TODO: Attempt UDP hole punch.
+		// TODO: client-relayed
+		return s.clientSelectRelay
+	}
+
+	return s.clientDial
+}
+
+// ----------------------------------------------------------------------------
+
+func (s *peerSupervisor) clientSelectRelay() stateFunc {
+	s.logf("STATE: client-select-relay")
+
+	timer := time.NewTimer(0)
+	defer timer.Stop()
+
+	for {
+		select {
+		case peer := <-s.peerUpdates:
+			return s.peerUpdate(peer)
+
+		case <-timer.C:
+			relay := s.selectRelay()
+			if relay != nil {
+				s.logf("Got relay: %d", relay.IP)
+				s.staged.RelayIP = relay.IP
+				s.staged.LocalAddr = relay.LocalAddr
+				s.publish()
+				return s.clientDial
+			}
+
+			s.logf("No relay available.")
+			timer.Reset(pingInterval)
+		}
+	}
+}
+
+func (s *peerSupervisor) selectRelay() *peerRoute {
+	possible := make([]*peerRoute, 0, 8)
+	for i := range routingTable {
+		route := routingTable[i].Load()
+		if !route.Up || !route.Relay {
+			continue
+		}
+		possible = append(possible, route)
+	}
+
+	if len(possible) == 0 {
+		return nil
+	}
+	return possible[rand.Intn(len(possible))]
+}
+
+// ----------------------------------------------------------------------------
+
+func (s *peerSupervisor) clientDial() stateFunc {
+	s.logf("STATE: client-dial")
+
+	var (
+		syn = synPacket{
+			TraceID:   newTraceID(),
+			SharedKey: s.staged.DataCipher.Key(),
+			RelayIP:   s.staged.RelayIP,
+		}
+
+		timeout = time.NewTimer(dialTimeout)
+	)
+
+	defer timeout.Stop()
+
+	s.sendControlPacket(syn)
+
+	for {
+		select {
+
+		case peer := <-s.peerUpdates:
+			return s.peerUpdate(peer)
+
+		case pkt := <-s.controlPackets:
+			switch p := pkt.Payload.(type) {
+			case synAckPacket:
+				if p.TraceID != syn.TraceID {
+					continue // Hmm...
+				}
+				s.sendControlPacket(ackPacket{TraceID: syn.TraceID, RecvAddr: pkt.RemoteAddr})
+				return s.clientConnected(p)
+			}
+
+		case <-timeout.C:
+			return s.clientInit
+		}
+	}
+}
+
+// ----------------------------------------------------------------------------
+
+func (s *peerSupervisor) clientConnected(p synAckPacket) stateFunc {
+	s.logf("STATE: client-connected")
+	s.staged.Up = true
+	s.staged.LocalAddr = p.RecvAddr
+	s.publish()
+
+	return func() stateFunc {
+		return s._clientConnected(p.TraceID)
+	}
+}
+
+func (s *peerSupervisor) _clientConnected(traceID uint64) stateFunc {
+
+	pingTimer := time.NewTimer(pingInterval)
+	timeoutTimer := time.NewTimer(timeoutInterval)
+
+	defer pingTimer.Stop()
+	defer timeoutTimer.Stop()
+
+	for {
+		select {
+		case peer := <-s.peerUpdates:
+			return s.peerUpdate(peer)
+
+		case pkt := <-s.controlPackets:
+			switch p := pkt.Payload.(type) {
+
+			case ackPacket:
+				if p.TraceID != traceID {
+					return s.clientInit
+				}
+				timeoutTimer.Reset(timeoutInterval)
+			}
+
+		case <-pingTimer.C:
+			s.sendControlPacket(ackPacket{TraceID: traceID})
+			pingTimer.Reset(pingInterval)
+
+		case <-timeoutTimer.C:
+			s.logf("client timeout")
+			return s.clientInit
+
+		}
+	}
 }

node/peer.go

@@ -1,274 +0,0 @@
-package node
-
-import (
-	"fmt"
-	"log"
-	"net/netip"
-	"sync/atomic"
-	"time"
-	"vppn/m"
-)
-
-type remotePeers [256]*remotePeer
-
-// ----------------------------------------------------------------------------
-
-type peerRouteInfo struct {
-	up            bool
-	relay         bool
-	controlCipher *controlCipher
-	dataCipher    *dataCipher
-	remoteAddr    netip.AddrPort
-	localAddr     netip.AddrPort // Local address as seen by the remote.
-	relayIP       byte           // Non-zero if we should relay.
-}
-
-type remotePeer struct {
-	// Immutable data.
-	localIP  byte
-	remoteIP byte
-	iface    *ifWriter
-	conn     *connWriter
-
-	// Shared state.
-	peers *remotePeers
-	route *atomic.Pointer[peerRouteInfo]
-
-	// Only used in HandlePacket / Not synchronized.
-	dupCheck   *dupCheck
-	decryptBuf []byte
-
-	// Only used in SendData / Not synchronized.
-	encryptBuf []byte
-
-	// Used for sending control and data packets. Atomic access only.
-	counter uint64
-
-	// Only accessed in HandlePeerUpdate. Used to determine if we should send
-	// the peer update to the peerSuper.
-	peerVersion int64
-
-	// For communicating with the supervisor thread.
-	peerUpdates    chan *m.Peer
-	controlPackets chan controlPacket
-}
-
-func newRemotePeer(conf m.PeerConfig, remoteIP byte, iface *ifWriter, conn *connWriter, peers *remotePeers) *remotePeer {
-	rp := &remotePeer{
-		localIP:        conf.PeerIP,
-		remoteIP:       remoteIP,
-		iface:          iface,
-		conn:           conn,
-		peers:          peers,
-		route:          &atomic.Pointer[peerRouteInfo]{},
-		dupCheck:       newDupCheck(0),
-		decryptBuf:     make([]byte, bufferSize),
-		encryptBuf:     make([]byte, bufferSize),
-		counter:        uint64(time.Now().Unix()) << 30,
-		peerUpdates:    make(chan *m.Peer),
-		controlPackets: make(chan controlPacket, 512),
-	}
-
-	pd := peerRouteInfo{}
-	rp.route.Store(&pd)
-
-	//go newPeerSuper(rp).Run()
-	go rp.supervise(conf)
-	return rp
-}
-
-func (rp *remotePeer) logf(msg string, args ...any) {
-	log.Printf(fmt.Sprintf("[%03d] ", rp.remoteIP)+msg, args...)
-}
-
-func (rp *remotePeer) HandlePeerUpdate(peer *m.Peer) {
-	if peer == nil {
-		rp.peerUpdates <- peer
-	} else if peer.Version != rp.peerVersion {
-		rp.peerVersion = peer.Version
-		rp.peerUpdates <- peer
-	}
-}
-
-// ----------------------------------------------------------------------------
-
-// HandlePacket accepts a raw data packet coming in from the network.
-//
-// This function is called by a single thread.
-func (rp *remotePeer) HandlePacket(addr netip.AddrPort, h header, data []byte) {
-	switch h.StreamID {
-	case controlStreamID:
-		rp.handleControlPacket(addr, h, data)
-
-	case dataStreamID:
-		rp.handleDataPacket(data)
-
-	case relayStreamID:
-		rp.handleRelayPacket(h, data)
-
-	default:
-		rp.logf("Unknown stream ID: %d", h.StreamID)
-	}
-}
-
-// ----------------------------------------------------------------------------
-
-func (rp *remotePeer) handleControlPacket(addr netip.AddrPort, h header, data []byte) {
-	routingData := rp.route.Load()
-	if routingData.controlCipher == nil {
-		rp.logf("Not connected (control).")
-		return
-	}
-
-	if h.DestIP != rp.localIP {
-		rp.logf("Incorrect destination IP on control packet.")
-		return
-	}
-
-	out, ok := routingData.controlCipher.Decrypt(data, rp.decryptBuf)
-	if !ok {
-		rp.logf("Failed to decrypt control packet.")
-		return
-	}
-
-	if len(out) == 0 {
-		rp.logf("Empty control packet from: %d", h.SourceIP)
-		return
-	}
-
-	if rp.dupCheck.IsDup(h.Counter) {
-		rp.logf("Duplicate control packet: %d", h.Counter)
-		return
-	}
-
-	pkt := controlPacket{
-		SrcIP:      h.SourceIP,
-		RemoteAddr: addr,
-	}
-
-	if err := pkt.ParsePayload(out); err != nil {
-		rp.logf("Failed to parse control packet: %v", err)
-		return
-	}
-
-	select {
-	case rp.controlPackets <- pkt:
-	default:
-		rp.logf("Dropping control packet.")
-	}
-}
-
-// ----------------------------------------------------------------------------
-
-func (rp *remotePeer) handleDataPacket(data []byte) {
-	routingData := rp.route.Load()
-	if routingData.dataCipher == nil {
-		rp.logf("Not connected (recv).")
-		return
-	}
-
-	dec, ok := routingData.dataCipher.Decrypt(data, rp.decryptBuf)
-	if !ok {
-		rp.logf("Failed to decrypt data packet.")
-		return
-	}
-
-	rp.iface.Write(dec)
-}
-
-// ----------------------------------------------------------------------------
-
-func (rp *remotePeer) handleRelayPacket(h header, data []byte) {
-	routingData := rp.route.Load()
-	if routingData.dataCipher == nil {
-		rp.logf("Not connected (recv).")
-		return
-	}
-
-	dec, ok := routingData.dataCipher.Decrypt(data, rp.decryptBuf)
-	if !ok {
-		rp.logf("Failed to decrypt data packet.")
-		return
-	}
-
-	rp.peers[h.DestIP].SendAsIs(dec)
-}
-
-// ----------------------------------------------------------------------------
-
-// SendData sends data coming from the interface going to the network.
-//
-// This function is called by a single thread.
-func (rp *remotePeer) SendData(data []byte) {
-	rp.encryptAndSend(dataStreamID, rp.remoteIP, data)
-}
-
-func (rp *remotePeer) HandleInterfacePacket(data []byte) {
-	routingData := rp.route.Load()
-
-	if routingData.dataCipher == nil {
-		rp.logf("Not connected (handle interface).")
-		return
-	}
-
-	h := header{
-		StreamID: dataStreamID,
-		Counter:  atomic.AddUint64(&rp.counter, 1),
-		SourceIP: rp.localIP,
-		DestIP:   rp.remoteIP,
-	}
-
-	enc := routingData.dataCipher.Encrypt(h, data, rp.encryptBuf)
-
-	if routingData.relayIP != 0 {
-		rp.peers[routingData.relayIP].RelayTo(rp.remoteIP, enc)
-	} else {
-		rp.SendData(data)
-	}
-}
-
-// ----------------------------------------------------------------------------
-
-func (rp *remotePeer) CanRelay() bool {
-	data := rp.route.Load()
-	return data.relay && data.up
-}
-
-// ----------------------------------------------------------------------------
-
-func (rp *remotePeer) RelayTo(destIP byte, data []byte) {
-	rp.encryptAndSend(relayStreamID, destIP, data)
-}
-
-// ----------------------------------------------------------------------------
-
-func (rp *remotePeer) encryptAndSend(streamID byte, destIP byte, data []byte) {
-	routingData := rp.route.Load()
-	if routingData.dataCipher == nil || routingData.remoteAddr == zeroAddrPort {
-		rp.logf("Not connected (encrypt and send).")
-		return
-	}
-
-	h := header{
-		StreamID: streamID,
-		Counter:  atomic.AddUint64(&rp.counter, 1),
-		SourceIP: rp.localIP,
-		DestIP:   destIP,
-	}
-
-	enc := routingData.dataCipher.Encrypt(h, data, rp.encryptBuf)
-	rp.conn.WriteTo(enc, routingData.remoteAddr)
-}
-
-// ----------------------------------------------------------------------------
-
-// SendAsIs is used when forwarding already-encrypted data from one peer to
-// another.
-func (rp *remotePeer) SendAsIs(data []byte) {
-	routingData := rp.route.Load()
-	if routingData.remoteAddr == zeroAddrPort {
-		rp.logf("Not connected (send direct).")
-		return
-	}
-	rp.conn.WriteTo(data, routingData.remoteAddr)
-}