eth, p2p: add trusted node list beside static list

Author: karalabe

eth/backend.go

@@ -41,8 +41,8 @@ var (
 		discover.MustParseNode("enode://487611428e6c99a11a9795a6abe7b529e81315ca6aad66e2a2fc76e3adf263faba0d35466c2f8f68d561dbefa8878d4df5f1f2ddb1fbeab7f42ffb8cd328bd4a@5.1.83.226:30303"),
 	}
 
-	// Path within <datadir> to search for the static node list
-	staticNodes = "static-nodes.json"
+	staticNodes  = "static-nodes.json"  // Path within <datadir> to search for the static node list
+	trustedNodes = "trusted-nodes.json" // Path within <datadir> to search for the trusted node list
 )
 
 type Config struct {
@@ -102,23 +102,22 @@ func (cfg *Config) parseBootNodes() []*discover.Node {
 	return ns
 }
 
-// parseStaticNodes parses a list of discovery node URLs either given literally,
-// or loaded from a .json file.
-func (cfg *Config) parseStaticNodes() []*discover.Node {
-	// Short circuit if no static node config is present
-	path := filepath.Join(cfg.DataDir, staticNodes)
+// parseNodes parses a list of discovery node URLs loaded from a .json file.
+func (cfg *Config) parseNodes(file string) []*discover.Node {
+	// Short circuit if no node config is present
+	path := filepath.Join(cfg.DataDir, file)
 	if _, err := os.Stat(path); err != nil {
 		return nil
 	}
-	// Load the static nodes from the config file
+	// Load the nodes from the config file
 	blob, err := ioutil.ReadFile(path)
 	if err != nil {
-		glog.V(logger.Error).Infof("Failed to access static nodes: %v", err)
+		glog.V(logger.Error).Infof("Failed to access nodes: %v", err)
 		return nil
 	}
 	nodelist := []string{}
 	if err := json.Unmarshal(blob, &nodelist); err != nil {
-		glog.V(logger.Error).Infof("Failed to load static nodes: %v", err)
+		glog.V(logger.Error).Infof("Failed to load nodes: %v", err)
 		return nil
 	}
 	// Interpret the list as a discovery node array
@@ -129,7 +128,7 @@ func (cfg *Config) parseStaticNodes() []*discover.Node {
 		}
 		node, err := discover.ParseNode(url)
 		if err != nil {
-			glog.V(logger.Error).Infof("Static node URL %s: %v\n", url, err)
+			glog.V(logger.Error).Infof("Node URL %s: %v\n", url, err)
 			continue
 		}
 		nodes = append(nodes, node)
@@ -288,7 +287,8 @@ func New(config *Config) (*Ethereum, error) {
 		NAT:            config.NAT,
 		NoDial:         !config.Dial,
 		BootstrapNodes: config.parseBootNodes(),
-		StaticNodes:    config.parseStaticNodes(),
+		StaticNodes:    config.parseNodes(staticNodes),
+		TrustedNodes:   config.parseNodes(trustedNodes),
 		NodeDatabase:   nodeDb,
 	}
 	if len(config.Port) > 0 {

p2p/handshake.go

@@ -70,21 +70,21 @@ type protoHandshake struct {
 // If dial is non-nil, the connection the local node is the initiator.
 // If atcap is true, the connection will be disconnected with DiscTooManyPeers
 // after the key exchange.
-func setupConn(fd net.Conn, prv *ecdsa.PrivateKey, our *protoHandshake, dial *discover.Node, atcap bool) (*conn, error) {
+func setupConn(fd net.Conn, prv *ecdsa.PrivateKey, our *protoHandshake, dial *discover.Node, atcap bool, trusted map[discover.NodeID]bool) (*conn, error) {
 	if dial == nil {
-		return setupInboundConn(fd, prv, our, atcap)
+		return setupInboundConn(fd, prv, our, atcap, trusted)
 	} else {
-		return setupOutboundConn(fd, prv, our, dial, atcap)
+		return setupOutboundConn(fd, prv, our, dial, atcap, trusted)
 	}
 }
 
-func setupInboundConn(fd net.Conn, prv *ecdsa.PrivateKey, our *protoHandshake, atcap bool) (*conn, error) {
+func setupInboundConn(fd net.Conn, prv *ecdsa.PrivateKey, our *protoHandshake, atcap bool, trusted map[discover.NodeID]bool) (*conn, error) {
 	secrets, err := receiverEncHandshake(fd, prv, nil)
 	if err != nil {
 		return nil, fmt.Errorf("encryption handshake failed: %v", err)
 	}
 	rw := newRlpxFrameRW(fd, secrets)
-	if atcap {
+	if atcap && !trusted[secrets.RemoteID] {
 		SendItems(rw, discMsg, DiscTooManyPeers)
 		return nil, errors.New("we have too many peers")
 	}
@@ -99,13 +99,13 @@ func setupInboundConn(fd net.Conn, prv *ecdsa.PrivateKey, our *protoHandshake, a
 	return &conn{rw, rhs}, nil
 }
 
-func setupOutboundConn(fd net.Conn, prv *ecdsa.PrivateKey, our *protoHandshake, dial *discover.Node, atcap bool) (*conn, error) {
+func setupOutboundConn(fd net.Conn, prv *ecdsa.PrivateKey, our *protoHandshake, dial *discover.Node, atcap bool, trusted map[discover.NodeID]bool) (*conn, error) {
 	secrets, err := initiatorEncHandshake(fd, prv, dial.ID, nil)
 	if err != nil {
 		return nil, fmt.Errorf("encryption handshake failed: %v", err)
 	}
 	rw := newRlpxFrameRW(fd, secrets)
-	if atcap {
+	if atcap && !trusted[secrets.RemoteID] {
 		SendItems(rw, discMsg, DiscTooManyPeers)
 		return nil, errors.New("we have too many peers")
 	}

p2p/handshake_test.go

@@ -143,7 +143,7 @@ func TestSetupConn(t *testing.T) {
 	done := make(chan struct{})
 	go func() {
 		defer close(done)
-		conn0, err := setupConn(fd0, prv0, hs0, node1, false)
+		conn0, err := setupConn(fd0, prv0, hs0, node1, false, nil)
 		if err != nil {
 			t.Errorf("outbound side error: %v", err)
 			return
@@ -156,7 +156,7 @@ func TestSetupConn(t *testing.T) {
 		}
 	}()
 
-	conn1, err := setupConn(fd1, prv1, hs1, nil, false)
+	conn1, err := setupConn(fd1, prv1, hs1, nil, false, nil)
 	if err != nil {
 		t.Fatalf("inbound side error: %v", err)
 	}

p2p/server.go

@@ -64,6 +64,10 @@ type Server struct {
 	// maintained and re-connected on disconnects.
 	StaticNodes []*discover.Node
 
+	// Trusted nodes are used as pre-configured connections which are always
+	// allowed to connect, even above the peer limit.
+	TrustedNodes []*discover.Node
+
 	// NodeDatabase is the path to the database containing the previously seen
 	// live nodes in the network.
 	NodeDatabase string
@@ -100,12 +104,13 @@ type Server struct {
 
 	ourHandshake *protoHandshake
 
-	lock        sync.RWMutex // protects running, peers and the trust fields
-	running     bool
-	peers       map[discover.NodeID]*Peer
-	staticNodes map[discover.NodeID]*discover.Node // Map of currently maintained static remote nodes
-	staticDial  chan *discover.Node                // Dial request channel reserved for the static nodes
-	staticCycle time.Duration                      // Overrides staticPeerCheckInterval, used for testing
+	lock         sync.RWMutex // protects running, peers and the trust fields
+	running      bool
+	peers        map[discover.NodeID]*Peer
+	staticNodes  map[discover.NodeID]*discover.Node // Map of currently maintained static remote nodes
+	staticDial   chan *discover.Node                // Dial request channel reserved for the static nodes
+	staticCycle  time.Duration                      // Overrides staticPeerCheckInterval, used for testing
+	trustedNodes map[discover.NodeID]bool           // Set of currently trusted remote nodes
 
 	ntab     *discover.Table
 	listener net.Listener
@@ -115,7 +120,7 @@ type Server struct {
 	peerWG sync.WaitGroup // active peer goroutines
 }
 
-type setupFunc func(net.Conn, *ecdsa.PrivateKey, *protoHandshake, *discover.Node, bool) (*conn, error)
+type setupFunc func(net.Conn, *ecdsa.PrivateKey, *protoHandshake, *discover.Node, bool, map[discover.NodeID]bool) (*conn, error)
 type newPeerHook func(*Peer)
 
 // Peers returns all connected peers.
@@ -207,7 +212,11 @@ func (srv *Server) Start() (err error) {
 	srv.quit = make(chan struct{})
 	srv.peers = make(map[discover.NodeID]*Peer)
 
-	// Create the current trust map, and the associated dialing channel
+	// Create the current trust maps, and the associated dialing channel
+	srv.trustedNodes = make(map[discover.NodeID]bool)
+	for _, node := range srv.TrustedNodes {
+		srv.trustedNodes[node.ID] = true
+	}
 	srv.staticNodes = make(map[discover.NodeID]*discover.Node)
 	for _, node := range srv.StaticNodes {
 		srv.staticNodes[node.ID] = node
@@ -486,7 +495,7 @@ func (srv *Server) startPeer(fd net.Conn, dest *discover.Node) {
 	}
 	srv.lock.RUnlock()
 
-	conn, err := srv.setupFunc(fd, srv.PrivateKey, srv.ourHandshake, dest, atcap)
+	conn, err := srv.setupFunc(fd, srv.PrivateKey, srv.ourHandshake, dest, atcap, srv.trustedNodes)
 	if err != nil {
 		fd.Close()
 		glog.V(logger.Debug).Infof("Handshake with %v failed: %v", fd.RemoteAddr(), err)
@@ -542,14 +551,15 @@ func (srv *Server) addPeer(id discover.NodeID, p *Peer) (bool, DiscReason) {
 // checkPeer verifies whether a peer looks promising and should be allowed/kept
 // in the pool, or if it's of no use.
 func (srv *Server) checkPeer(id discover.NodeID) (bool, DiscReason) {
-	// First up, figure out if the peer is static
+	// First up, figure out if the peer is static or trusted
 	_, static := srv.staticNodes[id]
+	trusted := srv.trustedNodes[id]
 
 	// Make sure the peer passes all required checks
 	switch {
 	case !srv.running:
 		return false, DiscQuitting
-	case !static && len(srv.peers) >= srv.MaxPeers:
+	case !static && !trusted && len(srv.peers) >= srv.MaxPeers:
 		return false, DiscTooManyPeers
 	case srv.peers[id] != nil:
 		return false, DiscAlreadyConnected

p2p/server_test.go

@@ -22,7 +22,7 @@ func startTestServer(t *testing.T, pf newPeerHook) *Server {
 		ListenAddr:  "127.0.0.1:0",
 		PrivateKey:  newkey(),
 		newPeerHook: pf,
-		setupFunc: func(fd net.Conn, prv *ecdsa.PrivateKey, our *protoHandshake, dial *discover.Node, atcap bool) (*conn, error) {
+		setupFunc: func(fd net.Conn, prv *ecdsa.PrivateKey, our *protoHandshake, dial *discover.Node, atcap bool, trusted map[discover.NodeID]bool) (*conn, error) {
 			id := randomID()
 			rw := newRlpxFrameRW(fd, secrets{
 				MAC:        zero16,
@@ -200,7 +200,7 @@ func TestServerDisconnectAtCap(t *testing.T) {
 		// Run the handshakes just like a real peer would.
 		key := newkey()
 		hs := &protoHandshake{Version: baseProtocolVersion, ID: discover.PubkeyID(&key.PublicKey)}
-		_, err = setupConn(conn, key, hs, srv.Self(), false)
+		_, err = setupConn(conn, key, hs, srv.Self(), false, srv.trustedNodes)
 		if i == nconns-1 {
 			// When handling the last connection, the server should
 			// disconnect immediately instead of running the protocol
@@ -250,7 +250,7 @@ func TestServerStaticPeers(t *testing.T) {
 		// Run the handshakes just like a real peer would, and wait for completion
 		key := newkey()
 		shake := &protoHandshake{Version: baseProtocolVersion, ID: discover.PubkeyID(&key.PublicKey)}
-		if _, err = setupConn(conn, key, shake, server.Self(), false); err != nil {
+		if _, err = setupConn(conn, key, shake, server.Self(), false, server.trustedNodes); err != nil {
 			t.Fatalf("conn %d: unexpected error: %v", i, err)
 		}
 		<-started
@@ -307,19 +307,24 @@ func TestServerStaticPeers(t *testing.T) {
 	}
 }
 
-/*
 // Tests that trusted peers and can connect above max peer caps.
 func TestServerTrustedPeers(t *testing.T) {
 	defer testlog(t).detach()
 
+	// Create a trusted peer to accept connections from
+	key := newkey()
+	trusted := &discover.Node{
+		ID: discover.PubkeyID(&key.PublicKey),
+	}
 	// Create a test server with limited connection slots
 	started := make(chan *Peer)
 	server := &Server{
-		ListenAddr:  "127.0.0.1:0",
-		PrivateKey:  newkey(),
-		MaxPeers:    3,
-		NoDial:      true,
-		newPeerHook: func(p *Peer) { started <- p },
+		ListenAddr:   "127.0.0.1:0",
+		PrivateKey:   newkey(),
+		MaxPeers:     3,
+		NoDial:       true,
+		TrustedNodes: []*discover.Node{trusted},
+		newPeerHook:  func(p *Peer) { started <- p },
 	}
 	if err := server.Start(); err != nil {
 		t.Fatal(err)
@@ -339,26 +344,20 @@ func TestServerTrustedPeers(t *testing.T) {
 		// Run the handshakes just like a real peer would, and wait for completion
 		key := newkey()
 		shake := &protoHandshake{Version: baseProtocolVersion, ID: discover.PubkeyID(&key.PublicKey)}
-		if _, err = setupConn(conn, key, shake, server.Self(), false); err != nil {
+		if _, err = setupConn(conn, key, shake, server.Self(), false, server.trustedNodes); err != nil {
 			t.Fatalf("conn %d: unexpected error: %v", i, err)
 		}
 		<-started
 	}
-	// Inject a trusted node and dial that (we'll connect from this end, don't need IP setup)
-	key := newkey()
-	trusted := &discover.Node{
-		ID: discover.PubkeyID(&key.PublicKey),
-	}
-	server.AddPeer(trusted)
-
+	// Dial from the trusted peer, ensure connection is accepted
 	conn, err := dialer.Dial("tcp", server.ListenAddr)
 	if err != nil {
 		t.Fatalf("trusted node: dial error: %v", err)
 	}
 	defer conn.Close()
 
 	shake := &protoHandshake{Version: baseProtocolVersion, ID: trusted.ID}
-	if _, err = setupConn(conn, key, shake, server.Self(), false); err != nil {
+	if _, err = setupConn(conn, key, shake, server.Self(), false, server.trustedNodes); err != nil {
 		t.Fatalf("trusted node: unexpected error: %v", err)
 	}
 	select {
@@ -369,7 +368,6 @@ func TestServerTrustedPeers(t *testing.T) {
 		t.Fatalf("trusted node timeout")
 	}
 }
-*/
 
 func newkey() *ecdsa.PrivateKey {
 	key, err := crypto.GenerateKey()