github.com/annchain/OG@v0.0.9/p2p/discv5/udp_test.go (about)

     1  // Copyright 2016 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 discv5
    18  
    19  import (
    20  	"encoding/hex"
    21  	"errors"
    22  	ogcrypto2 "github.com/annchain/OG/deprecated/ogcrypto"
    23  	"io"
    24  	"net"
    25  	"reflect"
    26  	"sync"
    27  	"testing"
    28  
    29  	"github.com/annchain/OG/common"
    30  	"github.com/davecgh/go-spew/spew"
    31  )
    32  
    33  func init() {
    34  	spew.Config.DisableMethods = true
    35  }
    36  
    37  // shared test variables
    38  var (
    39  	testLocal = RpcEndpoint{IP: net.ParseIP("3.3.3.3").To4(), UDP: 5, TCP: 6}
    40  )
    41  
    42  // type udpTest struct {
    43  // 	t                   *testing.T
    44  // 	pipe                *dgramPipe
    45  // 	table               *Table
    46  // 	udp                 *udp
    47  // 	sent                [][]byte
    48  // 	localkey, remotekey *ecdsa.PrivateKey
    49  // 	remoteaddr          *net.UDPAddr
    50  // }
    51  //
    52  // func newUDPTest(t *testing.T) *udpTest {
    53  // 	test := &udpTest{
    54  // 		t:          t,
    55  // 		pipe:       newpipe(),
    56  // 		localkey:   newkey(),
    57  // 		remotekey:  newkey(),
    58  // 		remoteaddr: &net.UDPAddr{IP: net.IP{1, 2, 3, 4}, Port: 30303},
    59  // 	}
    60  // 	test.table, test.udp, _ = newUDP(test.localkey, test.pipe, nil, "")
    61  // 	return test
    62  // }
    63  //
    64  // // handles a packet as if it had been sent to the transport.
    65  // func (test *udpTest) packetIn(wantError error, ptype byte, data packet) error {
    66  // 	enc, err := encodePacket(test.remotekey, ptype, data)
    67  // 	if err != nil {
    68  // 		return test.errorf("packet (%d) encode error: %v", ptype, err)
    69  // 	}
    70  // 	test.sent = append(test.sent, enc)
    71  // 	if err = test.udp.handlePacket(test.remoteaddr, enc); err != wantError {
    72  // 		return test.errorf("error mismatch: got %q, want %q", err, wantError)
    73  // 	}
    74  // 	return nil
    75  // }
    76  //
    77  // // waits for a packet to be sent by the transport.
    78  // // validate should have type func(*udpTest, X) error, where X is a packet type.
    79  // func (test *udpTest) waitPacketOut(validate interface{}) error {
    80  // 	dgram := test.pipe.waitPacketOut()
    81  // 	p, _, _, err := decodePacket(dgram)
    82  // 	if err != nil {
    83  // 		return test.errorf("sent packet decode error: %v", err)
    84  // 	}
    85  // 	fn := reflect.ValueOf(validate)
    86  // 	exptype := fn.Type().In(0)
    87  // 	if reflect.TypeOf(p) != exptype {
    88  // 		return test.errorf("sent packet type mismatch, got: %v, want: %v", reflect.TypeOf(p), exptype)
    89  // 	}
    90  // 	fn.Call([]reflect.Value{reflect.ValueOf(p)})
    91  // 	return nil
    92  // }
    93  //
    94  // func (test *udpTest) errorf(format string, args ...interface{}) error {
    95  // 	_, file, line, ok := runtime.Caller(2) // errorf + waitPacketOut
    96  // 	if ok {
    97  // 		file = filepath.Base(file)
    98  // 	} else {
    99  // 		file = "???"
   100  // 		line = 1
   101  // 	}
   102  // 	err := fmt.Errorf(format, args...)
   103  // 	fmt.Printf("\t%s:%d: %v\n", file, line, err)
   104  // 	test.t.Fail()
   105  // 	return err
   106  // }
   107  //
   108  // func TestUDP_packetErrors(t *testing.T) {
   109  // 	test := newUDPTest(t)
   110  // 	defer test.table.Close()
   111  //
   112  // 	test.packetIn(errExpired, pingPacket, &ping{From: testRemote, To: testLocalAnnounced, Version: Version})
   113  // 	test.packetIn(errUnsolicitedReply, pongPacket, &pong{ReplyTok: []byte{}, Expiration: futureExp})
   114  // 	test.packetIn(errUnknownNode, findnodePacket, &findnode{Expiration: futureExp})
   115  // 	test.packetIn(errUnsolicitedReply, neighborsPacket, &neighbors{Expiration: futureExp})
   116  // }
   117  //
   118  // func TestUDP_findnode(t *testing.T) {
   119  // 	test := newUDPTest(t)
   120  // 	defer test.table.Close()
   121  //
   122  // 	// put a few nodes into the table. their exact
   123  // 	// distribution shouldn't matter much, although we need to
   124  // 	// take care not to overflow any bucket.
   125  // 	targetHash := ogcrypto.Keccak256Hash(testTarget[:])
   126  // 	nodes := &nodesByDistance{target: targetHash}
   127  // 	for i := 0; i < bucketSize; i++ {
   128  // 		nodes.push(nodeAtDistance(test.table.self.sha, i+2), bucketSize)
   129  // 	}
   130  // 	test.table.stuff(nodes.entries)
   131  //
   132  // 	// ensure there's a bond with the test node,
   133  // 	// findnode won't be accepted otherwise.
   134  // 	test.table.db.updateNode(NewNode(
   135  // 		PubkeyID(&test.remotekey.PublicKey),
   136  // 		test.remoteaddr.IP,
   137  // 		uint16(test.remoteaddr.Port),
   138  // 		99,
   139  // 	))
   140  // 	// check that closest neighbors are returned.
   141  // 	test.packetIn(nil, findnodePacket, &findnode{Target: testTarget, Expiration: futureExp})
   142  // 	expected := test.table.closest(targetHash, bucketSize)
   143  //
   144  // 	waitNeighbors := func(want []*Node) {
   145  // 		test.waitPacketOut(func(p *neighbors) {
   146  // 			if len(p.Nodes) != len(want) {
   147  // 				t.Errorf("wrong number of results: got %d, want %d", len(p.Nodes), bucketSize)
   148  // 			}
   149  // 			for i := range p.Nodes {
   150  // 				if p.Nodes[i].ID != want[i].ID {
   151  // 					t.Errorf("result mismatch at %d:\n  got:  %v\n  want: %v", i, p.Nodes[i], expected.entries[i])
   152  // 				}
   153  // 			}
   154  // 		})
   155  // 	}
   156  // 	waitNeighbors(expected.entries[:maxNeighbors])
   157  // 	waitNeighbors(expected.entries[maxNeighbors:])
   158  // }
   159  //
   160  // func TestUDP_findnodeMultiReply(t *testing.T) {
   161  // 	test := newUDPTest(t)
   162  // 	defer test.table.Close()
   163  //
   164  // 	// queue a pending findnode request
   165  // 	resultc, errc := make(chan []*Node), make(chan error)
   166  // 	go func() {
   167  // 		rid := PubkeyID(&test.remotekey.PublicKey)
   168  // 		ns, err := test.udp.findnode(rid, test.remoteaddr, testTarget)
   169  // 		if err != nil && len(ns) == 0 {
   170  // 			errc <- err
   171  // 		} else {
   172  // 			resultc <- ns
   173  // 		}
   174  // 	}()
   175  //
   176  // 	// wait for the findnode to be sent.
   177  // 	// after it is sent, the transport is waiting for a reply
   178  // 	test.waitPacketOut(func(p *findnode) {
   179  // 		if p.Target != testTarget {
   180  // 			t.Errorf("wrong target: got %v, want %v", p.Target, testTarget)
   181  // 		}
   182  // 	})
   183  //
   184  // 	// send the reply as two packets.
   185  // 	list := []*Node{
   186  // 		MustParseNode("onode://ba85011c70bcc5c04d8607d3a0ed29aa6179c092cbdda10d5d32684fb33ed01bd94f588ca8f91ac48318087dcb02eaf36773a7a453f0eedd6742af668097b29c@10.0.1.16:30303?discport=30304"),
   187  // 		MustParseNode("onode://81fa361d25f157cd421c60dcc28d8dac5ef6a89476633339c5df30287474520caca09627da18543d9079b5b288698b542d56167aa5c09111e55acdbbdf2ef799@10.0.1.16:30303"),
   188  // 		MustParseNode("onode://9bffefd833d53fac8e652415f4973bee289e8b1a5c6c4cbe70abf817ce8a64cee11b823b66a987f51aaa9fba0d6a91b3e6bf0d5a5d1042de8e9eeea057b217f8@10.0.1.36:30301?discport=17"),
   189  // 		MustParseNode("onode://1b5b4aa662d7cb44a7221bfba67302590b643028197a7d5214790f3bac7aaa4a3241be9e83c09cf1f6c69d007c634faae3dc1b1221793e8446c0b3a09de65960@10.0.1.16:30303"),
   190  // 	}
   191  // 	rpclist := make([]rpcNode, len(list))
   192  // 	for i := range list {
   193  // 		rpclist[i] = nodeToRPC(list[i])
   194  // 	}
   195  // 	test.packetIn(nil, neighborsPacket, &neighbors{Expiration: futureExp, Nodes: rpclist[:2]})
   196  // 	test.packetIn(nil, neighborsPacket, &neighbors{Expiration: futureExp, Nodes: rpclist[2:]})
   197  //
   198  // 	// check that the sent neighbors are all returned by findnode
   199  // 	select {
   200  // 	case result := <-resultc:
   201  // 		if !reflect.DeepEqual(result, list) {
   202  // 			t.Errorf("neighbors mismatch:\n  got:  %v\n  want: %v", result, list)
   203  // 		}
   204  // 	case err := <-errc:
   205  // 		t.Errorf("findnode error: %v", err)
   206  // 	case <-time.After(5 * time.Second):
   207  // 		t.Error("findnode did not return within 5 seconds")
   208  // 	}
   209  // }
   210  //
   211  // func TestUDP_successfulPing(t *testing.T) {
   212  // 	test := newUDPTest(t)
   213  // 	added := make(chan *Node, 1)
   214  // 	test.table.nodeAddedHook = func(n *Node) { added <- n }
   215  // 	defer test.table.Close()
   216  //
   217  // 	// The remote side sends a ping packet to initiate the exchange.
   218  // 	go test.packetIn(nil, pingPacket, &ping{From: testRemote, To: testLocalAnnounced, Version: Version, Expiration: futureExp})
   219  //
   220  // 	// the ping is replied to.
   221  // 	test.waitPacketOut(func(p *pong) {
   222  // 		pinghash := test.sent[0][:macSize]
   223  // 		if !bytes.Equal(p.ReplyTok, pinghash) {
   224  // 			t.Errorf("got pong.ReplyTok %x, want %x", p.ReplyTok, pinghash)
   225  // 		}
   226  // 		wantTo := rpcEndpoint{
   227  // 			// The mirrored UDP address is the UDP packet sender
   228  // 			IP: test.remoteaddr.IP, UDP: uint16(test.remoteaddr.Port),
   229  // 			// The mirrored TCP port is the one from the ping packet
   230  // 			TCP: testRemote.TCP,
   231  // 		}
   232  // 		if !reflect.DeepEqual(p.To, wantTo) {
   233  // 			t.Errorf("got pong.To %v, want %v", p.To, wantTo)
   234  // 		}
   235  // 	})
   236  //
   237  // 	// remote is unknown, the table pings back.
   238  // 	test.waitPacketOut(func(p *ping) error {
   239  // 		if !reflect.DeepEqual(p.From, test.udp.ourEndpoint) {
   240  // 			t.Errorf("got ping.From %v, want %v", p.From, test.udp.ourEndpoint)
   241  // 		}
   242  // 		wantTo := rpcEndpoint{
   243  // 			// The mirrored UDP address is the UDP packet sender.
   244  // 			IP: test.remoteaddr.IP, UDP: uint16(test.remoteaddr.Port),
   245  // 			TCP: 0,
   246  // 		}
   247  // 		if !reflect.DeepEqual(p.To, wantTo) {
   248  // 			t.Errorf("got ping.To %v, want %v", p.To, wantTo)
   249  // 		}
   250  // 		return nil
   251  // 	})
   252  // 	test.packetIn(nil, pongPacket, &pong{Expiration: futureExp})
   253  //
   254  // 	// the node should be added to the table shortly after getting the
   255  // 	// pong packet.
   256  // 	select {
   257  // 	case n := <-added:
   258  // 		rid := PubkeyID(&test.remotekey.PublicKey)
   259  // 		if n.ID != rid {
   260  // 			t.Errorf("node has wrong ID: got %v, want %v", n.ID, rid)
   261  // 		}
   262  // 		if !bytes.Equal(n.IP, test.remoteaddr.IP) {
   263  // 			t.Errorf("node has wrong IP: got %v, want: %v", n.IP, test.remoteaddr.IP)
   264  // 		}
   265  // 		if int(n.UDP) != test.remoteaddr.Port {
   266  // 			t.Errorf("node has wrong UDP port: got %v, want: %v", n.UDP, test.remoteaddr.Port)
   267  // 		}
   268  // 		if n.TCP != testRemote.TCP {
   269  // 			t.Errorf("node has wrong TCP port: got %v, want: %v", n.TCP, testRemote.TCP)
   270  // 		}
   271  // 	case <-time.After(2 * time.Second):
   272  // 		t.Errorf("node was not added within 2 seconds")
   273  // 	}
   274  // }
   275  
   276  var testPackets = []struct {
   277  	input      string
   278  	wantPacket interface{}
   279  }{
   280  	{
   281  		input: "71dbda3a79554728d4f94411e42ee1f8b0d561c10e1e5f5893367948c6a7d70bb87b235fa28a77070271b6c164a2dce8c7e13a5739b53b5e96f2e5acb0e458a02902f5965d55ecbeb2ebb6cabb8b2b232896a36b737666c55265ad0a68412f250001ea04cb847f000001820cfa8215a8d790000000000000000000000000000000018208ae820d058443b9a355",
   282  		wantPacket: &Ping{
   283  			Version:    4,
   284  			From:       RpcEndpoint{net.ParseIP("127.0.0.1").To4(), 3322, 5544},
   285  			To:         RpcEndpoint{net.ParseIP("::1"), 2222, 3333},
   286  			Expiration: 1136239445,
   287  			Rest:       [][]byte{},
   288  		},
   289  	},
   290  	{
   291  		input: "e9614ccfd9fc3e74360018522d30e1419a143407ffcce748de3e22116b7e8dc92ff74788c0b6663aaa3d67d641936511c8f8d6ad8698b820a7cf9e1be7155e9a241f556658c55428ec0563514365799a4be2be5a685a80971ddcfa80cb422cdd0101ec04cb847f000001820cfa8215a8d790000000000000000000000000000000018208ae820d058443b9a3550102",
   292  		wantPacket: &Ping{
   293  			Version:    4,
   294  			From:       RpcEndpoint{net.ParseIP("127.0.0.1").To4(), 3322, 5544},
   295  			To:         RpcEndpoint{net.ParseIP("::1"), 2222, 3333},
   296  			Expiration: 1136239445,
   297  			Rest:       [][]byte{{0x01}, {0x02}},
   298  		},
   299  	},
   300  	{
   301  		input: "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",
   302  		wantPacket: &Ping{
   303  			Version:    555,
   304  			From:       RpcEndpoint{net.ParseIP("2001:db8:3c4d:15::abcd:ef12"), 3322, 5544},
   305  			To:         RpcEndpoint{net.ParseIP("2001:db8:85a3:8d3:1319:8a2e:370:7348"), 2222, 33338},
   306  			Expiration: 1136239445,
   307  			Rest:       [][]byte{{0xC5, 0x01, 0x02, 0x03, 0x04, 0x05}},
   308  		},
   309  	},
   310  	{
   311  		input: "09b2428d83348d27cdf7064ad9024f526cebc19e4958f0fdad87c15eb598dd61d08423e0bf66b2069869e1724125f820d851c136684082774f870e614d95a2855d000f05d1648b2d5945470bc187c2d2216fbe870f43ed0909009882e176a46b0102f846d79020010db885a308d313198a2e037073488208ae82823aa0fbc914b16819237dcd8801d7e53f69e9719adecb3cc0e790c57e91ca4461c9548443b9a355c6010203c2040506a0c969a58f6f9095004c0177a6b47f451530cab38966a25cca5cb58f055542124e",
   312  		wantPacket: &Pong{
   313  			To:         RpcEndpoint{net.ParseIP("2001:db8:85a3:8d3:1319:8a2e:370:7348"), 2222, 33338},
   314  			ReplyTok:   common.Hex2BytesNoError("fbc914b16819237dcd8801d7e53f69e9719adecb3cc0e790c57e91ca4461c954"),
   315  			Expiration: 1136239445,
   316  			Rest:       [][]byte{{0xC6, 0x01, 0x02, 0x03, 0xC2, 0x04, 0x05}, {0x06}},
   317  		},
   318  	},
   319  	{
   320  		input: "c7c44041b9f7c7e41934417ebac9a8e1a4c6298f74553f2fcfdcae6ed6fe53163eb3d2b52e39fe91831b8a927bf4fc222c3902202027e5e9eb812195f95d20061ef5cd31d502e47ecb61183f74a504fe04c51e73df81f25c4d506b26db4517490103f84eb840ca634cae0d49acb401d8a4c6b6fe8c55b70d115bf400769cc1400f3258cd31387574077f301b421bc84df7266c44e9e6d569fc56be00812904767bf5ccd1fc7f8443b9a35582999983999999280dc62cc8255c73471e0a61da0c89acdc0e035e260add7fc0c04ad9ebf3919644c91cb247affc82b69bd2ca235c71eab8e49737c937a2c396",
   321  		wantPacket: &Findnode{
   322  			Target:     MustHexID("ca634cae0d49acb401d8a4c6b6fe8c55b70d115bf400769cc1400f3258cd31387574077f301b421bc84df7266c44e9e6d569fc56be00812904767bf5ccd1fc7f"),
   323  			Expiration: 1136239445,
   324  			Rest:       [][]byte{{0x82, 0x99, 0x99}, {0x83, 0x99, 0x99, 0x99}},
   325  		},
   326  	},
   327  	{
   328  		input: "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",
   329  		wantPacket: &Neighbors{
   330  			Nodes: []RpcNode{
   331  				{
   332  					ID:  MustHexID("3155e1427f85f10a5c9a7755877748041af1bcd8d474ec065eb33df57a97babf54bfd2103575fa829115d224c523596b401065a97f74010610fce76382c0bf32"),
   333  					IP:  net.ParseIP("99.33.22.55").To4(),
   334  					UDP: 4444,
   335  					TCP: 4445,
   336  				},
   337  				{
   338  					ID:  MustHexID("312c55512422cf9b8a4097e9a6ad79402e87a15ae909a4bfefa22398f03d20951933beea1e4dfa6f968212385e829f04c2d314fc2d4e255e0d3bc08792b069db"),
   339  					IP:  net.ParseIP("1.2.3.4").To4(),
   340  					UDP: 1,
   341  					TCP: 1,
   342  				},
   343  				{
   344  					ID:  MustHexID("38643200b172dcfef857492156971f0e6aa2c538d8b74010f8e140811d53b98c765dd2d96126051913f44582e8c199ad7c6d6819e9a56483f637feaac9448aac"),
   345  					IP:  net.ParseIP("2001:db8:3c4d:15::abcd:ef12"),
   346  					UDP: 3333,
   347  					TCP: 3333,
   348  				},
   349  				{
   350  					ID:  MustHexID("8dcab8618c3253b558d459da53bd8fa68935a719aff8b811197101a4b2b47dd2d47295286fc00cc081bb542d760717d1bdd6bec2c37cd72eca367d6dd3b9df73"),
   351  					IP:  net.ParseIP("2001:db8:85a3:8d3:1319:8a2e:370:7348"),
   352  					UDP: 999,
   353  					TCP: 1000,
   354  				},
   355  			},
   356  			Expiration: 1136239445,
   357  			Rest:       [][]byte{{0x01}, {0x02}, {0x03}},
   358  		},
   359  	},
   360  }
   361  
   362  func TestForwardCompatibility(t *testing.T) {
   363  	t.Skip("skipped while working on discovery v5")
   364  
   365  	testkey, _ := ogcrypto2.HexToECDSA("b71c71a67e1177ad4e901695e1b4b9ee17ae16c6668d313eac2f96dbcda3f291")
   366  	wantNodeID := PubkeyID(&testkey.PublicKey)
   367  
   368  	for _, test := range testPackets {
   369  		input, err := hex.DecodeString(test.input)
   370  		if err != nil {
   371  			t.Fatalf("invalid hex: %s", test.input)
   372  		}
   373  		var pkt ingressPacket
   374  		if err := decodePacket(input, &pkt); err != nil {
   375  			t.Errorf("did not accept packet %s\n%v", test.input, err)
   376  			continue
   377  		}
   378  		if !reflect.DeepEqual(pkt.data, test.wantPacket) {
   379  			t.Errorf("got %s\nwant %s", spew.Sdump(pkt.data), spew.Sdump(test.wantPacket))
   380  		}
   381  		if pkt.remoteID != wantNodeID {
   382  			t.Errorf("got id %v\nwant id %v", pkt.remoteID, wantNodeID)
   383  		}
   384  	}
   385  }
   386  
   387  // dgramPipe is a fake UDP socket. It queues all sent datagrams.
   388  type dgramPipe struct {
   389  	mu      *sync.Mutex
   390  	cond    *sync.Cond
   391  	closing chan struct{}
   392  	closed  bool
   393  	queue   [][]byte
   394  }
   395  
   396  func newpipe() *dgramPipe {
   397  	mu := new(sync.Mutex)
   398  	return &dgramPipe{
   399  		closing: make(chan struct{}),
   400  		cond:    &sync.Cond{L: mu},
   401  		mu:      mu,
   402  	}
   403  }
   404  
   405  // WriteToUDP queues a datagram.
   406  func (c *dgramPipe) WriteToUDP(b []byte, to *net.UDPAddr) (n int, err error) {
   407  	msg := make([]byte, len(b))
   408  	copy(msg, b)
   409  	c.mu.Lock()
   410  	defer c.mu.Unlock()
   411  	if c.closed {
   412  		return 0, errors.New("closed")
   413  	}
   414  	c.queue = append(c.queue, msg)
   415  	c.cond.Signal()
   416  	return len(b), nil
   417  }
   418  
   419  // ReadFromUDP just hangs until the pipe is closed.
   420  func (c *dgramPipe) ReadFromUDP(b []byte) (n int, addr *net.UDPAddr, err error) {
   421  	<-c.closing
   422  	return 0, nil, io.EOF
   423  }
   424  
   425  func (c *dgramPipe) Close() error {
   426  	c.mu.Lock()
   427  	defer c.mu.Unlock()
   428  	if !c.closed {
   429  		close(c.closing)
   430  		c.closed = true
   431  	}
   432  	return nil
   433  }
   434  
   435  func (c *dgramPipe) LocalAddr() net.Addr {
   436  	return &net.UDPAddr{IP: testLocal.IP, Port: int(testLocal.UDP)}
   437  }
   438  
   439  func (c *dgramPipe) waitPacketOut() []byte {
   440  	c.mu.Lock()
   441  	defer c.mu.Unlock()
   442  	for len(c.queue) == 0 {
   443  		c.cond.Wait()
   444  	}
   445  	p := c.queue[0]
   446  	copy(c.queue, c.queue[1:])
   447  	c.queue = c.queue[:len(c.queue)-1]
   448  	return p
   449  }