github.com/kisexp/xdchain@v0.0.0-20211206025815-490d6b732aa7/p2p/server_test.go (about)

     1  // Copyright 2014 The go-ethereum Authors
     2  // This file is part of the go-ethereum library.
     3  //
     4  // The go-ethereum library is free software: you can redistribute it and/or modify
     5  // it under the terms of the GNU Lesser General Public License as published by
     6  // the Free Software Foundation, either version 3 of the License, or
     7  // (at your option) any later version.
     8  //
     9  // The go-ethereum library is distributed in the hope that it will be useful,
    10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
    11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    12  // GNU Lesser General Public License for more details.
    13  //
    14  // You should have received a copy of the GNU Lesser General Public License
    15  // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
    16  
    17  package p2p
    18  
    19  import (
    20  	"crypto/ecdsa"
    21  	"crypto/sha256"
    22  	"errors"
    23  	"io"
    24  	"io/ioutil"
    25  	"math/rand"
    26  	"net"
    27  	"os"
    28  	"path"
    29  	"reflect"
    30  	"testing"
    31  	"time"
    32  
    33  	"github.com/kisexp/xdchain/crypto"
    34  	"github.com/kisexp/xdchain/internal/testlog"
    35  	"github.com/kisexp/xdchain/log"
    36  	"github.com/kisexp/xdchain/p2p/enode"
    37  	"github.com/kisexp/xdchain/p2p/enr"
    38  	"github.com/kisexp/xdchain/p2p/rlpx"
    39  	"github.com/kisexp/xdchain/params"
    40  	"github.com/stretchr/testify/assert"
    41  )
    42  
    43  type testTransport struct {
    44  	*rlpxTransport
    45  	rpub     *ecdsa.PublicKey
    46  	closeErr error
    47  }
    48  
    49  func newTestTransport(rpub *ecdsa.PublicKey, fd net.Conn, dialDest *ecdsa.PublicKey) transport {
    50  	wrapped := newRLPX(fd, dialDest).(*rlpxTransport)
    51  	wrapped.conn.InitWithSecrets(rlpx.Secrets{
    52  		AES:        make([]byte, 16),
    53  		MAC:        make([]byte, 16),
    54  		EgressMAC:  sha256.New(),
    55  		IngressMAC: sha256.New(),
    56  	})
    57  	return &testTransport{rpub: rpub, rlpxTransport: wrapped}
    58  }
    59  
    60  func (c *testTransport) doEncHandshake(prv *ecdsa.PrivateKey) (*ecdsa.PublicKey, error) {
    61  	return c.rpub, nil
    62  }
    63  
    64  func (c *testTransport) doProtoHandshake(our *protoHandshake) (*protoHandshake, error) {
    65  	pubkey := crypto.FromECDSAPub(c.rpub)[1:]
    66  	return &protoHandshake{ID: pubkey, Name: "test"}, nil
    67  }
    68  
    69  func (c *testTransport) close(err error) {
    70  	c.conn.Close()
    71  	c.closeErr = err
    72  }
    73  
    74  func startTestServer(t *testing.T, remoteKey *ecdsa.PublicKey, pf func(*Peer)) *Server {
    75  	config := Config{
    76  		Name:        "test",
    77  		MaxPeers:    10,
    78  		ListenAddr:  "127.0.0.1:0",
    79  		NoDiscovery: true,
    80  		PrivateKey:  newkey(),
    81  		Logger:      testlog.Logger(t, log.LvlTrace),
    82  	}
    83  	server := &Server{
    84  		Config:      config,
    85  		newPeerHook: pf,
    86  		newTransport: func(fd net.Conn, dialDest *ecdsa.PublicKey) transport {
    87  			return newTestTransport(remoteKey, fd, dialDest)
    88  		},
    89  	}
    90  	if err := server.Start(); err != nil {
    91  		t.Fatalf("Could not start server: %v", err)
    92  	}
    93  	return server
    94  }
    95  
    96  func TestServerListen(t *testing.T) {
    97  	// start the test server
    98  	connected := make(chan *Peer)
    99  	remid := &newkey().PublicKey
   100  	srv := startTestServer(t, remid, func(p *Peer) {
   101  		if p.ID() != enode.PubkeyToIDV4(remid) {
   102  			t.Error("peer func called with wrong node id")
   103  		}
   104  		connected <- p
   105  	})
   106  	defer close(connected)
   107  	defer srv.Stop()
   108  
   109  	// dial the test server
   110  	conn, err := net.DialTimeout("tcp", srv.ListenAddr, 5*time.Second)
   111  	if err != nil {
   112  		t.Fatalf("could not dial: %v", err)
   113  	}
   114  	defer conn.Close()
   115  
   116  	select {
   117  	case peer := <-connected:
   118  		if peer.LocalAddr().String() != conn.RemoteAddr().String() {
   119  			t.Errorf("peer started with wrong conn: got %v, want %v",
   120  				peer.LocalAddr(), conn.RemoteAddr())
   121  		}
   122  		peers := srv.Peers()
   123  		if !reflect.DeepEqual(peers, []*Peer{peer}) {
   124  			t.Errorf("Peers mismatch: got %v, want %v", peers, []*Peer{peer})
   125  		}
   126  	case <-time.After(1 * time.Second):
   127  		t.Error("server did not accept within one second")
   128  	}
   129  }
   130  
   131  func TestServerDial(t *testing.T) {
   132  	// run a one-shot TCP server to handle the connection.
   133  	listener, err := net.Listen("tcp", "127.0.0.1:0")
   134  	if err != nil {
   135  		t.Fatalf("could not setup listener: %v", err)
   136  	}
   137  	defer listener.Close()
   138  	accepted := make(chan net.Conn, 1)
   139  	go func() {
   140  		conn, err := listener.Accept()
   141  		if err != nil {
   142  			return
   143  		}
   144  		accepted <- conn
   145  	}()
   146  
   147  	// start the server
   148  	connected := make(chan *Peer)
   149  	remid := &newkey().PublicKey
   150  	srv := startTestServer(t, remid, func(p *Peer) { connected <- p })
   151  	defer close(connected)
   152  	defer srv.Stop()
   153  
   154  	// tell the server to connect
   155  	tcpAddr := listener.Addr().(*net.TCPAddr)
   156  	node := enode.NewV4(remid, tcpAddr.IP, tcpAddr.Port, 0)
   157  	srv.AddPeer(node)
   158  
   159  	select {
   160  	case conn := <-accepted:
   161  		defer conn.Close()
   162  
   163  		select {
   164  		case peer := <-connected:
   165  			if peer.ID() != enode.PubkeyToIDV4(remid) {
   166  				t.Errorf("peer has wrong id")
   167  			}
   168  			if peer.Name() != "test" {
   169  				t.Errorf("peer has wrong name")
   170  			}
   171  			if peer.RemoteAddr().String() != conn.LocalAddr().String() {
   172  				t.Errorf("peer started with wrong conn: got %v, want %v",
   173  					peer.RemoteAddr(), conn.LocalAddr())
   174  			}
   175  			peers := srv.Peers()
   176  			if !reflect.DeepEqual(peers, []*Peer{peer}) {
   177  				t.Errorf("Peers mismatch: got %v, want %v", peers, []*Peer{peer})
   178  			}
   179  
   180  			// Test AddTrustedPeer/RemoveTrustedPeer and changing Trusted flags
   181  			// Particularly for race conditions on changing the flag state.
   182  			if peer := srv.Peers()[0]; peer.Info().Network.Trusted {
   183  				t.Errorf("peer is trusted prematurely: %v", peer)
   184  			}
   185  			done := make(chan bool)
   186  			go func() {
   187  				srv.AddTrustedPeer(node)
   188  				if peer := srv.Peers()[0]; !peer.Info().Network.Trusted {
   189  					t.Errorf("peer is not trusted after AddTrustedPeer: %v", peer)
   190  				}
   191  				srv.RemoveTrustedPeer(node)
   192  				if peer := srv.Peers()[0]; peer.Info().Network.Trusted {
   193  					t.Errorf("peer is trusted after RemoveTrustedPeer: %v", peer)
   194  				}
   195  				done <- true
   196  			}()
   197  			// Trigger potential race conditions
   198  			peer = srv.Peers()[0]
   199  			_ = peer.Inbound()
   200  			_ = peer.Info()
   201  			<-done
   202  		case <-time.After(1 * time.Second):
   203  			t.Error("server did not launch peer within one second")
   204  		}
   205  
   206  	case <-time.After(1 * time.Second):
   207  		t.Error("server did not connect within one second")
   208  	}
   209  }
   210  
   211  // This test checks that RemovePeer disconnects the peer if it is connected.
   212  func TestServerRemovePeerDisconnect(t *testing.T) {
   213  	srv1 := &Server{Config: Config{
   214  		PrivateKey:  newkey(),
   215  		MaxPeers:    1,
   216  		NoDiscovery: true,
   217  		Logger:      testlog.Logger(t, log.LvlTrace).New("server", "1"),
   218  	}}
   219  	srv2 := &Server{Config: Config{
   220  		PrivateKey:  newkey(),
   221  		MaxPeers:    1,
   222  		NoDiscovery: true,
   223  		NoDial:      true,
   224  		ListenAddr:  "127.0.0.1:0",
   225  		Logger:      testlog.Logger(t, log.LvlTrace).New("server", "2"),
   226  	}}
   227  	srv1.Start()
   228  	defer srv1.Stop()
   229  	srv2.Start()
   230  	defer srv2.Stop()
   231  
   232  	if !syncAddPeer(srv1, srv2.Self()) {
   233  		t.Fatal("peer not connected")
   234  	}
   235  	srv1.RemovePeer(srv2.Self())
   236  	if srv1.PeerCount() > 0 {
   237  		t.Fatal("removed peer still connected")
   238  	}
   239  }
   240  
   241  // This test checks that connections are disconnected just after the encryption handshake
   242  // when the server is at capacity. Trusted connections should still be accepted.
   243  func TestServerAtCap(t *testing.T) {
   244  	trustedNode := newkey()
   245  	trustedID := enode.PubkeyToIDV4(&trustedNode.PublicKey)
   246  	srv := &Server{
   247  		Config: Config{
   248  			PrivateKey:   newkey(),
   249  			MaxPeers:     10,
   250  			NoDial:       true,
   251  			NoDiscovery:  true,
   252  			TrustedNodes: []*enode.Node{newNode(trustedID, "")},
   253  			Logger:       testlog.Logger(t, log.LvlTrace),
   254  		},
   255  	}
   256  	if err := srv.Start(); err != nil {
   257  		t.Fatalf("could not start: %v", err)
   258  	}
   259  	defer srv.Stop()
   260  
   261  	newconn := func(id enode.ID) *conn {
   262  		fd, _ := net.Pipe()
   263  		tx := newTestTransport(&trustedNode.PublicKey, fd, nil)
   264  		node := enode.SignNull(new(enr.Record), id)
   265  		return &conn{fd: fd, transport: tx, flags: inboundConn, node: node, cont: make(chan error)}
   266  	}
   267  
   268  	// Inject a few connections to fill up the peer set.
   269  	for i := 0; i < 10; i++ {
   270  		c := newconn(randomID())
   271  		if err := srv.checkpoint(c, srv.checkpointAddPeer); err != nil {
   272  			t.Fatalf("could not add conn %d: %v", i, err)
   273  		}
   274  	}
   275  	// Try inserting a non-trusted connection.
   276  	anotherID := randomID()
   277  	c := newconn(anotherID)
   278  	if err := srv.checkpoint(c, srv.checkpointPostHandshake); err != DiscTooManyPeers {
   279  		t.Error("wrong error for insert:", err)
   280  	}
   281  	// Try inserting a trusted connection.
   282  	c = newconn(trustedID)
   283  	if err := srv.checkpoint(c, srv.checkpointPostHandshake); err != nil {
   284  		t.Error("unexpected error for trusted conn @posthandshake:", err)
   285  	}
   286  	if !c.is(trustedConn) {
   287  		t.Error("Server did not set trusted flag")
   288  	}
   289  
   290  	// Remove from trusted set and try again
   291  	srv.RemoveTrustedPeer(newNode(trustedID, ""))
   292  	c = newconn(trustedID)
   293  	if err := srv.checkpoint(c, srv.checkpointPostHandshake); err != DiscTooManyPeers {
   294  		t.Error("wrong error for insert:", err)
   295  	}
   296  
   297  	// Add anotherID to trusted set and try again
   298  	srv.AddTrustedPeer(newNode(anotherID, ""))
   299  	c = newconn(anotherID)
   300  	if err := srv.checkpoint(c, srv.checkpointPostHandshake); err != nil {
   301  		t.Error("unexpected error for trusted conn @posthandshake:", err)
   302  	}
   303  	if !c.is(trustedConn) {
   304  		t.Error("Server did not set trusted flag")
   305  	}
   306  }
   307  
   308  func TestServerPeerLimits(t *testing.T) {
   309  	srvkey := newkey()
   310  	clientkey := newkey()
   311  	clientnode := enode.NewV4(&clientkey.PublicKey, nil, 0, 0)
   312  
   313  	var tp = &setupTransport{
   314  		pubkey: &clientkey.PublicKey,
   315  		phs: protoHandshake{
   316  			ID: crypto.FromECDSAPub(&clientkey.PublicKey)[1:],
   317  			// Force "DiscUselessPeer" due to unmatching caps
   318  			// Caps: []Cap{discard.cap()},
   319  		},
   320  	}
   321  
   322  	srv := &Server{
   323  		Config: Config{
   324  			PrivateKey:  srvkey,
   325  			MaxPeers:    0,
   326  			NoDial:      true,
   327  			NoDiscovery: true,
   328  			Protocols:   []Protocol{discard},
   329  			Logger:      testlog.Logger(t, log.LvlTrace),
   330  		},
   331  		newTransport: func(fd net.Conn, dialDest *ecdsa.PublicKey) transport { return tp },
   332  	}
   333  	if err := srv.Start(); err != nil {
   334  		t.Fatalf("couldn't start server: %v", err)
   335  	}
   336  	defer srv.Stop()
   337  
   338  	// Check that server is full (MaxPeers=0)
   339  	flags := dynDialedConn
   340  	dialDest := clientnode
   341  	conn, _ := net.Pipe()
   342  	srv.SetupConn(conn, flags, dialDest)
   343  	if tp.closeErr != DiscTooManyPeers {
   344  		t.Errorf("unexpected close error: %q", tp.closeErr)
   345  	}
   346  	conn.Close()
   347  
   348  	srv.AddTrustedPeer(clientnode)
   349  
   350  	// Check that server allows a trusted peer despite being full.
   351  	conn, _ = net.Pipe()
   352  	srv.SetupConn(conn, flags, dialDest)
   353  	if tp.closeErr == DiscTooManyPeers {
   354  		t.Errorf("failed to bypass MaxPeers with trusted node: %q", tp.closeErr)
   355  	}
   356  
   357  	if tp.closeErr != DiscUselessPeer {
   358  		t.Errorf("unexpected close error: %q", tp.closeErr)
   359  	}
   360  	conn.Close()
   361  
   362  	srv.RemoveTrustedPeer(clientnode)
   363  
   364  	// Check that server is full again.
   365  	conn, _ = net.Pipe()
   366  	srv.SetupConn(conn, flags, dialDest)
   367  	if tp.closeErr != DiscTooManyPeers {
   368  		t.Errorf("unexpected close error: %q", tp.closeErr)
   369  	}
   370  	conn.Close()
   371  }
   372  
   373  func TestServerSetupConn(t *testing.T) {
   374  	var (
   375  		clientkey, srvkey = newkey(), newkey()
   376  		clientpub         = &clientkey.PublicKey
   377  		srvpub            = &srvkey.PublicKey
   378  	)
   379  	tests := []struct {
   380  		dontstart bool
   381  		tt        *setupTransport
   382  		flags     connFlag
   383  		dialDest  *enode.Node
   384  
   385  		wantCloseErr error
   386  		wantCalls    string
   387  	}{
   388  		{
   389  			dontstart:    true,
   390  			tt:           &setupTransport{pubkey: clientpub},
   391  			wantCalls:    "close,",
   392  			wantCloseErr: errServerStopped,
   393  		},
   394  		{
   395  			tt:           &setupTransport{pubkey: clientpub, encHandshakeErr: errors.New("read error")},
   396  			flags:        inboundConn,
   397  			wantCalls:    "doEncHandshake,close,",
   398  			wantCloseErr: errors.New("read error"),
   399  		},
   400  		{
   401  			tt:           &setupTransport{pubkey: clientpub, phs: protoHandshake{ID: randomID().Bytes()}},
   402  			dialDest:     enode.NewV4(clientpub, nil, 0, 0),
   403  			flags:        dynDialedConn,
   404  			wantCalls:    "doEncHandshake,doProtoHandshake,close,",
   405  			wantCloseErr: DiscUnexpectedIdentity,
   406  		},
   407  		{
   408  			tt:           &setupTransport{pubkey: clientpub, protoHandshakeErr: errors.New("foo")},
   409  			dialDest:     enode.NewV4(clientpub, nil, 0, 0),
   410  			flags:        dynDialedConn,
   411  			wantCalls:    "doEncHandshake,doProtoHandshake,close,",
   412  			wantCloseErr: errors.New("foo"),
   413  		},
   414  		{
   415  			tt:           &setupTransport{pubkey: srvpub, phs: protoHandshake{ID: crypto.FromECDSAPub(srvpub)[1:]}},
   416  			flags:        inboundConn,
   417  			wantCalls:    "doEncHandshake,close,",
   418  			wantCloseErr: DiscSelf,
   419  		},
   420  		{
   421  			tt:           &setupTransport{pubkey: clientpub, phs: protoHandshake{ID: crypto.FromECDSAPub(clientpub)[1:]}},
   422  			flags:        inboundConn,
   423  			wantCalls:    "doEncHandshake,doProtoHandshake,close,",
   424  			wantCloseErr: DiscUselessPeer,
   425  		},
   426  	}
   427  
   428  	for i, test := range tests {
   429  		t.Run(test.wantCalls, func(t *testing.T) {
   430  			cfg := Config{
   431  				PrivateKey:  srvkey,
   432  				MaxPeers:    10,
   433  				NoDial:      true,
   434  				NoDiscovery: true,
   435  				Protocols:   []Protocol{discard},
   436  				Logger:      testlog.Logger(t, log.LvlTrace),
   437  			}
   438  			srv := &Server{
   439  				Config:       cfg,
   440  				newTransport: func(fd net.Conn, dialDest *ecdsa.PublicKey) transport { return test.tt },
   441  				log:          cfg.Logger,
   442  			}
   443  			if !test.dontstart {
   444  				if err := srv.Start(); err != nil {
   445  					t.Fatalf("couldn't start server: %v", err)
   446  				}
   447  				defer srv.Stop()
   448  			}
   449  			p1, _ := net.Pipe()
   450  			srv.SetupConn(p1, test.flags, test.dialDest)
   451  			if !reflect.DeepEqual(test.tt.closeErr, test.wantCloseErr) {
   452  				t.Errorf("test %d: close error mismatch: got %q, want %q", i, test.tt.closeErr, test.wantCloseErr)
   453  			}
   454  			if test.tt.calls != test.wantCalls {
   455  				t.Errorf("test %d: calls mismatch: got %q, want %q", i, test.tt.calls, test.wantCalls)
   456  			}
   457  		})
   458  	}
   459  }
   460  
   461  func TestServerSetupConn_whenNotInRaftCluster(t *testing.T) {
   462  	var (
   463  		clientkey, srvkey = newkey(), newkey()
   464  		clientpub         = &clientkey.PublicKey
   465  	)
   466  
   467  	clientNode := enode.NewV4(clientpub, nil, 0, 0)
   468  	srv := &Server{
   469  		Config: Config{
   470  			PrivateKey:  srvkey,
   471  			NoDiscovery: true,
   472  		},
   473  		newTransport: func(fd net.Conn, key *ecdsa.PublicKey) transport { return newTestTransport(clientpub, fd, key) },
   474  		log:          log.New(),
   475  		checkPeerInRaft: func(node *enode.Node) bool {
   476  			return false
   477  		},
   478  	}
   479  	if err := srv.Start(); err != nil {
   480  		t.Fatalf("couldn't start server: %v", err)
   481  	}
   482  	defer srv.Stop()
   483  	p1, _ := net.Pipe()
   484  	err := srv.SetupConn(p1, inboundConn, clientNode)
   485  
   486  	assert.IsType(t, &peerError{}, err)
   487  	perr := err.(*peerError)
   488  	t.Log(perr.Error())
   489  	assert.Equal(t, errNotInRaftCluster, perr.code)
   490  }
   491  
   492  func TestServerSetupConn_whenNotPermissioned(t *testing.T) {
   493  	tmpDir, err := ioutil.TempDir("", "")
   494  	if err != nil {
   495  		t.Fatal(err)
   496  	}
   497  	defer func() { _ = os.RemoveAll(tmpDir) }()
   498  	if err := ioutil.WriteFile(path.Join(tmpDir, params.PERMISSIONED_CONFIG), []byte("[]"), 0644); err != nil {
   499  		t.Fatal(err)
   500  	}
   501  	var (
   502  		clientkey, srvkey = newkey(), newkey()
   503  		clientpub         = &clientkey.PublicKey
   504  	)
   505  	clientNode := enode.NewV4(clientpub, nil, 0, 0)
   506  	srv := &Server{
   507  		Config: Config{
   508  			PrivateKey:           srvkey,
   509  			NoDiscovery:          true,
   510  			DataDir:              tmpDir,
   511  			EnableNodePermission: true,
   512  		},
   513  		newTransport: func(fd net.Conn, key *ecdsa.PublicKey) transport { return newTestTransport(clientpub, fd, key) },
   514  		log:          log.New(),
   515  	}
   516  	if err := srv.Start(); err != nil {
   517  		t.Fatalf("couldn't start server: %v", err)
   518  	}
   519  	defer srv.Stop()
   520  	p1, _ := net.Pipe()
   521  	err = srv.SetupConn(p1, inboundConn, clientNode)
   522  
   523  	assert.IsType(t, &peerError{}, err)
   524  	perr := err.(*peerError)
   525  	t.Log(perr.Error())
   526  	assert.Equal(t, errPermissionDenied, perr.code)
   527  }
   528  
   529  type setupTransport struct {
   530  	pubkey            *ecdsa.PublicKey
   531  	encHandshakeErr   error
   532  	phs               protoHandshake
   533  	protoHandshakeErr error
   534  
   535  	calls    string
   536  	closeErr error
   537  }
   538  
   539  func (c *setupTransport) doEncHandshake(prv *ecdsa.PrivateKey) (*ecdsa.PublicKey, error) {
   540  	c.calls += "doEncHandshake,"
   541  	return c.pubkey, c.encHandshakeErr
   542  }
   543  
   544  func (c *setupTransport) doProtoHandshake(our *protoHandshake) (*protoHandshake, error) {
   545  	c.calls += "doProtoHandshake,"
   546  	if c.protoHandshakeErr != nil {
   547  		return nil, c.protoHandshakeErr
   548  	}
   549  	return &c.phs, nil
   550  }
   551  func (c *setupTransport) close(err error) {
   552  	c.calls += "close,"
   553  	c.closeErr = err
   554  }
   555  
   556  // setupConn shouldn't write to/read from the connection.
   557  func (c *setupTransport) WriteMsg(Msg) error {
   558  	panic("WriteMsg called on setupTransport")
   559  }
   560  func (c *setupTransport) ReadMsg() (Msg, error) {
   561  	panic("ReadMsg called on setupTransport")
   562  }
   563  
   564  func newkey() *ecdsa.PrivateKey {
   565  	key, err := crypto.GenerateKey()
   566  	if err != nil {
   567  		panic("couldn't generate key: " + err.Error())
   568  	}
   569  	return key
   570  }
   571  
   572  func randomID() (id enode.ID) {
   573  	for i := range id {
   574  		id[i] = byte(rand.Intn(255))
   575  	}
   576  	return id
   577  }
   578  
   579  // This test checks that inbound connections are throttled by IP.
   580  func TestServerInboundThrottle(t *testing.T) {
   581  	const timeout = 5 * time.Second
   582  	newTransportCalled := make(chan struct{})
   583  	srv := &Server{
   584  		Config: Config{
   585  			PrivateKey:  newkey(),
   586  			ListenAddr:  "127.0.0.1:0",
   587  			MaxPeers:    10,
   588  			NoDial:      true,
   589  			NoDiscovery: true,
   590  			Protocols:   []Protocol{discard},
   591  			Logger:      testlog.Logger(t, log.LvlTrace),
   592  		},
   593  		newTransport: func(fd net.Conn, dialDest *ecdsa.PublicKey) transport {
   594  			newTransportCalled <- struct{}{}
   595  			return newRLPX(fd, dialDest)
   596  		},
   597  		listenFunc: func(network, laddr string) (net.Listener, error) {
   598  			fakeAddr := &net.TCPAddr{IP: net.IP{95, 33, 21, 2}, Port: 4444}
   599  			return listenFakeAddr(network, laddr, fakeAddr)
   600  		},
   601  	}
   602  	if err := srv.Start(); err != nil {
   603  		t.Fatal("can't start: ", err)
   604  	}
   605  	defer srv.Stop()
   606  
   607  	// Dial the test server.
   608  	conn, err := net.DialTimeout("tcp", srv.ListenAddr, timeout)
   609  	if err != nil {
   610  		t.Fatalf("could not dial: %v", err)
   611  	}
   612  	select {
   613  	case <-newTransportCalled:
   614  		// OK
   615  	case <-time.After(timeout):
   616  		t.Error("newTransport not called")
   617  	}
   618  	conn.Close()
   619  
   620  	// Dial again. This time the server should close the connection immediately.
   621  	connClosed := make(chan struct{}, 1)
   622  	conn, err = net.DialTimeout("tcp", srv.ListenAddr, timeout)
   623  	if err != nil {
   624  		t.Fatalf("could not dial: %v", err)
   625  	}
   626  	defer conn.Close()
   627  	go func() {
   628  		conn.SetDeadline(time.Now().Add(timeout))
   629  		buf := make([]byte, 10)
   630  		if n, err := conn.Read(buf); err != io.EOF || n != 0 {
   631  			t.Errorf("expected io.EOF and n == 0, got error %q and n == %d", err, n)
   632  		}
   633  		connClosed <- struct{}{}
   634  	}()
   635  	select {
   636  	case <-connClosed:
   637  		// OK
   638  	case <-newTransportCalled:
   639  		t.Error("newTransport called for second attempt")
   640  	case <-time.After(timeout):
   641  		t.Error("connection not closed within timeout")
   642  	}
   643  }
   644  
   645  func listenFakeAddr(network, laddr string, remoteAddr net.Addr) (net.Listener, error) {
   646  	l, err := net.Listen(network, laddr)
   647  	if err == nil {
   648  		l = &fakeAddrListener{l, remoteAddr}
   649  	}
   650  	return l, err
   651  }
   652  
   653  // fakeAddrListener is a listener that creates connections with a mocked remote address.
   654  type fakeAddrListener struct {
   655  	net.Listener
   656  	remoteAddr net.Addr
   657  }
   658  
   659  type fakeAddrConn struct {
   660  	net.Conn
   661  	remoteAddr net.Addr
   662  }
   663  
   664  func (l *fakeAddrListener) Accept() (net.Conn, error) {
   665  	c, err := l.Listener.Accept()
   666  	if err != nil {
   667  		return nil, err
   668  	}
   669  	return &fakeAddrConn{c, l.remoteAddr}, nil
   670  }
   671  
   672  func (c *fakeAddrConn) RemoteAddr() net.Addr {
   673  	return c.remoteAddr
   674  }
   675  
   676  func syncAddPeer(srv *Server, node *enode.Node) bool {
   677  	var (
   678  		ch      = make(chan *PeerEvent)
   679  		sub     = srv.SubscribeEvents(ch)
   680  		timeout = time.After(2 * time.Second)
   681  	)
   682  	defer sub.Unsubscribe()
   683  	srv.AddPeer(node)
   684  	for {
   685  		select {
   686  		case ev := <-ch:
   687  			if ev.Type == PeerEventTypeAdd && ev.Peer == node.ID() {
   688  				return true
   689  			}
   690  		case <-timeout:
   691  			return false
   692  		}
   693  	}
   694  }