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p2p/discover: implement v5.1 wire protocol (#21647)

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This change implements the Discovery v5.1 wire protocol and
also adds an interactive test suite for this protocol.
This commit is contained in:
Felix Lange
2020-10-14 12:28:17 +02:00
committed by GitHub
parent 4eb01b21c8
commit 524aaf5ec6
24 changed files with 3236 additions and 1427 deletions
Download Patch File Download Diff File Expand all files Collapse all files

86
cmd/devp2p/README.md Normal file
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@ -0,0 +1,86 @@
# The devp2p command
The devp2p command line tool is a utility for low-level peer-to-peer debugging and
protocol development purposes. It can do many things.
### ENR Decoding
Use `devp2p enrdump <base64>` to verify and display an Ethereum Node Record.
### Node Key Management
The `devp2p key ...` command family deals with node key files.
Run `devp2p key generate mynode.key` to create a new node key in the `mynode.key` file.
Run `devp2p key to-enode mynode.key -ip 127.0.0.1 -tcp 30303` to create an enode:// URL
corresponding to the given node key and address information.
### Maintaining DNS Discovery Node Lists
The devp2p command can create and publish DNS discovery node lists.
Run `devp2p dns sign <directory>` to update the signature of a DNS discovery tree.
Run `devp2p dns sync <enrtree-URL>` to download a complete DNS discovery tree.
Run `devp2p dns to-cloudflare <directory>` to publish a tree to CloudFlare DNS.
Run `devp2p dns to-route53 <directory>` to publish a tree to Amazon Route53.
You can find more information about these commands in the [DNS Discovery Setup Guide][dns-tutorial].
### Discovery v4 Utilities
The `devp2p discv4 ...` command family deals with the [Node Discovery v4][discv4]
protocol.
Run `devp2p discv4 ping <enode/ENR>` to ping a node.
Run `devp2p discv4 resolve <enode/ENR>` to find the most recent node record of a node in
the DHT.
Run `devp2p discv4 crawl <nodes.json path>` to create or update a JSON node set.
### Discovery v5 Utilities
The `devp2p discv5 ...` command family deals with the [Node Discovery v5][discv5]
protocol. This protocol is currently under active development.
Run `devp2p discv5 ping <ENR>` to ping a node.
Run `devp2p discv5 resolve <ENR>` to find the most recent node record of a node in
the discv5 DHT.
Run `devp2p discv5 listen` to run a Discovery v5 node.
Run `devp2p discv5 crawl <nodes.json path>` to create or update a JSON node set containing
discv5 nodes.
### Discovery Test Suites
The devp2p command also contains interactive test suites for Discovery v4 and Discovery
v5.
To run these tests against your implementation, you need to set up a networking
environment where two separate UDP listening addresses are available on the same machine.
The two listening addresses must also be routed such that they are able to reach the node
you want to test.
For example, if you want to run the test on your local host, and the node under test is
also on the local host, you need to assign two IP addresses (or a larger range) to your
loopback interface. On macOS, this can be done by executing the following command:
sudo ifconfig lo0 add 127.0.0.2
You can now run either test suite as follows: Start the node under test first, ensuring
that it won't talk to the Internet (i.e. disable bootstrapping). An easy way to prevent
unintended connections to the global DHT is listening on `127.0.0.1`.
Now get the ENR of your node and store it in the `NODE` environment variable.
Start the test by running `devp2p discv5 test -listen1 127.0.0.1 -listen2 127.0.0.2 $NODE`.
[dns-tutorial]: https://geth.ethereum.org/docs/developers/dns-discovery-setup
[discv4]: https://github.com/ethereum/devp2p/tree/master/discv4.md
[discv5]: https://github.com/ethereum/devp2p/tree/master/discv5/discv5.md

12
cmd/devp2p/discv4cmd.go
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@ -286,7 +286,11 @@ func listen(ln *enode.LocalNode, addr string) *net.UDPConn {
}
usocket := socket.(*net.UDPConn)
uaddr := socket.LocalAddr().(*net.UDPAddr)
ln.SetFallbackIP(net.IP{127, 0, 0, 1})
if uaddr.IP.IsUnspecified() {
ln.SetFallbackIP(net.IP{127, 0, 0, 1})
} else {
ln.SetFallbackIP(uaddr.IP)
}
ln.SetFallbackUDP(uaddr.Port)
return usocket
}
@ -294,7 +298,11 @@ func listen(ln *enode.LocalNode, addr string) *net.UDPConn {
func parseBootnodes(ctx *cli.Context) ([]*enode.Node, error) {
s := params.RinkebyBootnodes
if ctx.IsSet(bootnodesFlag.Name) {
s = strings.Split(ctx.String(bootnodesFlag.Name), ",")
input := ctx.String(bootnodesFlag.Name)
if input == "" {
return nil, nil
}
s = strings.Split(input, ",")
}
nodes := make([]*enode.Node, len(s))
var err error

35
cmd/devp2p/discv5cmd.go
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@ -18,9 +18,13 @@ package main
import (
"fmt"
"os"
"time"
"github.com/ethereum/go-ethereum/cmd/devp2p/internal/v5test"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/internal/utesting"
"github.com/ethereum/go-ethereum/log"
"github.com/ethereum/go-ethereum/p2p/discover"
"gopkg.in/urfave/cli.v1"
)
@ -33,6 +37,7 @@ var (
discv5PingCommand,
discv5ResolveCommand,
discv5CrawlCommand,
discv5TestCommand,
discv5ListenCommand,
},
}
@ -53,6 +58,12 @@ var (
Action: discv5Crawl,
Flags: []cli.Flag{bootnodesFlag, crawlTimeoutFlag},
}
discv5TestCommand = cli.Command{
Name: "test",
Usage: "Runs protocol tests against a node",
Action: discv5Test,
Flags: []cli.Flag{testPatternFlag, testListen1Flag, testListen2Flag},
}
discv5ListenCommand = cli.Command{
Name: "listen",
Usage: "Runs a node",
@ -103,6 +114,30 @@ func discv5Crawl(ctx *cli.Context) error {
return nil
}
func discv5Test(ctx *cli.Context) error {
// Disable logging unless explicitly enabled.
if !ctx.GlobalIsSet("verbosity") && !ctx.GlobalIsSet("vmodule") {
log.Root().SetHandler(log.DiscardHandler())
}
// Filter and run test cases.
suite := &v5test.Suite{
Dest: getNodeArg(ctx),
Listen1: ctx.String(testListen1Flag.Name),
Listen2: ctx.String(testListen2Flag.Name),
}
tests := suite.AllTests()
if ctx.IsSet(testPatternFlag.Name) {
tests = utesting.MatchTests(tests, ctx.String(testPatternFlag.Name))
}
results := utesting.RunTests(tests, os.Stdout)
if fails := utesting.CountFailures(results); fails > 0 {
return fmt.Errorf("%v/%v tests passed.", len(tests)-fails, len(tests))
}
fmt.Printf("%v/%v passed\n", len(tests), len(tests))
return nil
}
func discv5Listen(ctx *cli.Context) error {
disc := startV5(ctx)
defer disc.Close()

377
cmd/devp2p/internal/v5test/discv5tests.go Normal file
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@ -0,0 +1,377 @@
// Copyright 2020 The go-ethereum Authors
// This file is part of go-ethereum.
//
// go-ethereum is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// go-ethereum is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with go-ethereum. If not, see <http://www.gnu.org/licenses/>.
package v5test
import (
"bytes"
"net"
"sync"
"time"
"github.com/ethereum/go-ethereum/internal/utesting"
"github.com/ethereum/go-ethereum/p2p/discover/v5wire"
"github.com/ethereum/go-ethereum/p2p/enode"
"github.com/ethereum/go-ethereum/p2p/netutil"
)
// Suite is the discv5 test suite.
type Suite struct {
Dest *enode.Node
Listen1, Listen2 string // listening addresses
}
func (s *Suite) listen1(log logger) (*conn, net.PacketConn) {
c := newConn(s.Dest, log)
l := c.listen(s.Listen1)
return c, l
}
func (s *Suite) listen2(log logger) (*conn, net.PacketConn, net.PacketConn) {
c := newConn(s.Dest, log)
l1, l2 := c.listen(s.Listen1), c.listen(s.Listen2)
return c, l1, l2
}
func (s *Suite) AllTests() []utesting.Test {
return []utesting.Test{
{Name: "Ping", Fn: s.TestPing},
{Name: "PingLargeRequestID", Fn: s.TestPingLargeRequestID},
{Name: "PingMultiIP", Fn: s.TestPingMultiIP},
{Name: "PingHandshakeInterrupted", Fn: s.TestPingHandshakeInterrupted},
{Name: "TalkRequest", Fn: s.TestTalkRequest},
{Name: "FindnodeZeroDistance", Fn: s.TestFindnodeZeroDistance},
{Name: "FindnodeResults", Fn: s.TestFindnodeResults},
}
}
// This test sends PING and expects a PONG response.
func (s *Suite) TestPing(t *utesting.T) {
conn, l1 := s.listen1(t)
defer conn.close()
ping := &v5wire.Ping{ReqID: conn.nextReqID()}
switch resp := conn.reqresp(l1, ping).(type) {
case *v5wire.Pong:
checkPong(t, resp, ping, l1)
default:
t.Fatal("expected PONG, got", resp.Name())
}
}
func checkPong(t *utesting.T, pong *v5wire.Pong, ping *v5wire.Ping, c net.PacketConn) {
if !bytes.Equal(pong.ReqID, ping.ReqID) {
t.Fatalf("wrong request ID %x in PONG, want %x", pong.ReqID, ping.ReqID)
}
if !pong.ToIP.Equal(laddr(c).IP) {
t.Fatalf("wrong destination IP %v in PONG, want %v", pong.ToIP, laddr(c).IP)
}
if int(pong.ToPort) != laddr(c).Port {
t.Fatalf("wrong destination port %v in PONG, want %v", pong.ToPort, laddr(c).Port)
}
}
// This test sends PING with a 9-byte request ID, which isn't allowed by the spec.
// The remote node should not respond.
func (s *Suite) TestPingLargeRequestID(t *utesting.T) {
conn, l1 := s.listen1(t)
defer conn.close()
ping := &v5wire.Ping{ReqID: make([]byte, 9)}
switch resp := conn.reqresp(l1, ping).(type) {
case *v5wire.Pong:
t.Errorf("PONG response with unknown request ID %x", resp.ReqID)
case *readError:
if resp.err == v5wire.ErrInvalidReqID {
t.Error("response with oversized request ID")
} else if !netutil.IsTimeout(resp.err) {
t.Error(resp)
}
}
}
// In this test, a session is established from one IP as usual. The session is then reused
// on another IP, which shouldn't work. The remote node should respond with WHOAREYOU for
// the attempt from a different IP.
func (s *Suite) TestPingMultiIP(t *utesting.T) {
conn, l1, l2 := s.listen2(t)
defer conn.close()
// Create the session on l1.
ping := &v5wire.Ping{ReqID: conn.nextReqID()}
resp := conn.reqresp(l1, ping)
if resp.Kind() != v5wire.PongMsg {
t.Fatal("expected PONG, got", resp)
}
checkPong(t, resp.(*v5wire.Pong), ping, l1)
// Send on l2. This reuses the session because there is only one codec.
ping2 := &v5wire.Ping{ReqID: conn.nextReqID()}
conn.write(l2, ping2, nil)
switch resp := conn.read(l2).(type) {
case *v5wire.Pong:
t.Fatalf("remote responded to PING from %v for session on IP %v", laddr(l2).IP, laddr(l1).IP)
case *v5wire.Whoareyou:
t.Logf("got WHOAREYOU for new session as expected")
resp.Node = s.Dest
conn.write(l2, ping2, resp)
default:
t.Fatal("expected WHOAREYOU, got", resp)
}
// Catch the PONG on l2.
switch resp := conn.read(l2).(type) {
case *v5wire.Pong:
checkPong(t, resp, ping2, l2)
default:
t.Fatal("expected PONG, got", resp)
}
// Try on l1 again.
ping3 := &v5wire.Ping{ReqID: conn.nextReqID()}
conn.write(l1, ping3, nil)
switch resp := conn.read(l1).(type) {
case *v5wire.Pong:
t.Fatalf("remote responded to PING from %v for session on IP %v", laddr(l1).IP, laddr(l2).IP)
case *v5wire.Whoareyou:
t.Logf("got WHOAREYOU for new session as expected")
default:
t.Fatal("expected WHOAREYOU, got", resp)
}
}
// This test starts a handshake, but doesn't finish it and sends a second ordinary message
// packet instead of a handshake message packet. The remote node should respond with
// another WHOAREYOU challenge for the second packet.
func (s *Suite) TestPingHandshakeInterrupted(t *utesting.T) {
conn, l1 := s.listen1(t)
defer conn.close()
// First PING triggers challenge.
ping := &v5wire.Ping{ReqID: conn.nextReqID()}
conn.write(l1, ping, nil)
switch resp := conn.read(l1).(type) {
case *v5wire.Whoareyou:
t.Logf("got WHOAREYOU for PING")
default:
t.Fatal("expected WHOAREYOU, got", resp)
}
// Send second PING.
ping2 := &v5wire.Ping{ReqID: conn.nextReqID()}
switch resp := conn.reqresp(l1, ping2).(type) {
case *v5wire.Pong:
checkPong(t, resp, ping2, l1)
default:
t.Fatal("expected WHOAREYOU, got", resp)
}
}
// This test sends TALKREQ and expects an empty TALKRESP response.
func (s *Suite) TestTalkRequest(t *utesting.T) {
conn, l1 := s.listen1(t)
defer conn.close()
// Non-empty request ID.
id := conn.nextReqID()
resp := conn.reqresp(l1, &v5wire.TalkRequest{ReqID: id, Protocol: "test-protocol"})
switch resp := resp.(type) {
case *v5wire.TalkResponse:
if !bytes.Equal(resp.ReqID, id) {
t.Fatalf("wrong request ID %x in TALKRESP, want %x", resp.ReqID, id)
}
if len(resp.Message) > 0 {
t.Fatalf("non-empty message %x in TALKRESP", resp.Message)
}
default:
t.Fatal("expected TALKRESP, got", resp.Name())
}
// Empty request ID.
resp = conn.reqresp(l1, &v5wire.TalkRequest{Protocol: "test-protocol"})
switch resp := resp.(type) {
case *v5wire.TalkResponse:
if len(resp.ReqID) > 0 {
t.Fatalf("wrong request ID %x in TALKRESP, want empty byte array", resp.ReqID)
}
if len(resp.Message) > 0 {
t.Fatalf("non-empty message %x in TALKRESP", resp.Message)
}
default:
t.Fatal("expected TALKRESP, got", resp.Name())
}
}
// This test checks that the remote node returns itself for FINDNODE with distance zero.
func (s *Suite) TestFindnodeZeroDistance(t *utesting.T) {
conn, l1 := s.listen1(t)
defer conn.close()
nodes, err := conn.findnode(l1, []uint{0})
if err != nil {
t.Fatal(err)
}
if len(nodes) != 1 {
t.Fatalf("remote returned more than one node for FINDNODE [0]")
}
if nodes[0].ID() != conn.remote.ID() {
t.Errorf("ID of response node is %v, want %v", nodes[0].ID(), conn.remote.ID())
}
}
// In this test, multiple nodes ping the node under test. After waiting for them to be
// accepted into the remote table, the test checks that they are returned by FINDNODE.
func (s *Suite) TestFindnodeResults(t *utesting.T) {
// Create bystanders.
nodes := make([]*bystander, 5)
added := make(chan enode.ID, len(nodes))
for i := range nodes {
nodes[i] = newBystander(t, s, added)
defer nodes[i].close()
}
// Get them added to the remote table.
timeout := 60 * time.Second
timeoutCh := time.After(timeout)
for count := 0; count < len(nodes); {
select {
case id := <-added:
t.Logf("bystander node %v added to remote table", id)
count++
case <-timeoutCh:
t.Errorf("remote added %d bystander nodes in %v, need %d to continue", count, timeout, len(nodes))
t.Logf("this can happen if the node has a non-empty table from previous runs")
return
}
}
t.Logf("all %d bystander nodes were added", len(nodes))
// Collect our nodes by distance.
var dists []uint
expect := make(map[enode.ID]*enode.Node)
for _, bn := range nodes {
n := bn.conn.localNode.Node()
expect[n.ID()] = n
d := uint(enode.LogDist(n.ID(), s.Dest.ID()))
if !containsUint(dists, d) {
dists = append(dists, d)
}
}
// Send FINDNODE for all distances.
conn, l1 := s.listen1(t)
defer conn.close()
foundNodes, err := conn.findnode(l1, dists)
if err != nil {
t.Fatal(err)
}
t.Logf("remote returned %d nodes for distance list %v", len(foundNodes), dists)
for _, n := range foundNodes {
delete(expect, n.ID())
}
if len(expect) > 0 {
t.Errorf("missing %d nodes in FINDNODE result", len(expect))
t.Logf("this can happen if the test is run multiple times in quick succession")
t.Logf("and the remote node hasn't removed dead nodes from previous runs yet")
} else {
t.Logf("all %d expected nodes were returned", len(nodes))
}
}
// A bystander is a node whose only purpose is filling a spot in the remote table.
type bystander struct {
dest *enode.Node
conn *conn
l net.PacketConn
addedCh chan enode.ID
done sync.WaitGroup
}
func newBystander(t *utesting.T, s *Suite, added chan enode.ID) *bystander {
conn, l := s.listen1(t)
conn.setEndpoint(l) // bystander nodes need IP/port to get pinged
bn := &bystander{
conn: conn,
l: l,
dest: s.Dest,
addedCh: added,
}
bn.done.Add(1)
go bn.loop()
return bn
}
// id returns the node ID of the bystander.
func (bn *bystander) id() enode.ID {
return bn.conn.localNode.ID()
}
// close shuts down loop.
func (bn *bystander) close() {
bn.conn.close()
bn.done.Wait()
}
// loop answers packets from the remote node until quit.
func (bn *bystander) loop() {
defer bn.done.Done()
var (
lastPing time.Time
wasAdded bool
)
for {
// Ping the remote node.
if !wasAdded && time.Since(lastPing) > 10*time.Second {
bn.conn.reqresp(bn.l, &v5wire.Ping{
ReqID: bn.conn.nextReqID(),
ENRSeq: bn.dest.Seq(),
})
lastPing = time.Now()
}
// Answer packets.
switch p := bn.conn.read(bn.l).(type) {
case *v5wire.Ping:
bn.conn.write(bn.l, &v5wire.Pong{
ReqID: p.ReqID,
ENRSeq: bn.conn.localNode.Seq(),
ToIP: bn.dest.IP(),
ToPort: uint16(bn.dest.UDP()),
}, nil)
wasAdded = true
bn.notifyAdded()
case *v5wire.Findnode:
bn.conn.write(bn.l, &v5wire.Nodes{ReqID: p.ReqID, Total: 1}, nil)
wasAdded = true
bn.notifyAdded()
case *v5wire.TalkRequest:
bn.conn.write(bn.l, &v5wire.TalkResponse{ReqID: p.ReqID}, nil)
case *readError:
if !netutil.IsTemporaryError(p.err) {
bn.conn.logf("shutting down: %v", p.err)
return
}
}
}
}
func (bn *bystander) notifyAdded() {
if bn.addedCh != nil {
bn.addedCh <- bn.id()
bn.addedCh = nil
}
}

263
cmd/devp2p/internal/v5test/framework.go Normal file
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@ -0,0 +1,263 @@
// Copyright 2020 The go-ethereum Authors
// This file is part of go-ethereum.
//
// go-ethereum is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// go-ethereum is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with go-ethereum. If not, see <http://www.gnu.org/licenses/>.
package v5test
import (
"bytes"
"crypto/ecdsa"
"encoding/binary"
"fmt"
"net"
"time"
"github.com/ethereum/go-ethereum/common/mclock"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/p2p/discover/v5wire"
"github.com/ethereum/go-ethereum/p2p/enode"
"github.com/ethereum/go-ethereum/p2p/enr"
)
// readError represents an error during packet reading.
// This exists to facilitate type-switching on the result of conn.read.
type readError struct {
err error
}
func (p *readError) Kind() byte { return 99 }
func (p *readError) Name() string { return fmt.Sprintf("error: %v", p.err) }
func (p *readError) Error() string { return p.err.Error() }
func (p *readError) Unwrap() error { return p.err }
func (p *readError) RequestID() []byte { return nil }
func (p *readError) SetRequestID([]byte) {}
// readErrorf creates a readError with the given text.
func readErrorf(format string, args ...interface{}) *readError {
return &readError{fmt.Errorf(format, args...)}
}
// This is the response timeout used in tests.
const waitTime = 300 * time.Millisecond
// conn is a connection to the node under test.
type conn struct {
localNode *enode.LocalNode
localKey *ecdsa.PrivateKey
remote *enode.Node
remoteAddr *net.UDPAddr
listeners []net.PacketConn
log logger
codec *v5wire.Codec
lastRequest v5wire.Packet
lastChallenge *v5wire.Whoareyou
idCounter uint32
}
type logger interface {
Logf(string, ...interface{})
}
// newConn sets up a connection to the given node.
func newConn(dest *enode.Node, log logger) *conn {
key, err := crypto.GenerateKey()
if err != nil {
panic(err)
}
db, err := enode.OpenDB("")
if err != nil {
panic(err)
}
ln := enode.NewLocalNode(db, key)
return &conn{
localKey: key,
localNode: ln,
remote: dest,
remoteAddr: &net.UDPAddr{IP: dest.IP(), Port: dest.UDP()},
codec: v5wire.NewCodec(ln, key, mclock.System{}),
log: log,
}
}
func (tc *conn) setEndpoint(c net.PacketConn) {
tc.localNode.SetStaticIP(laddr(c).IP)
tc.localNode.SetFallbackUDP(laddr(c).Port)
}
func (tc *conn) listen(ip string) net.PacketConn {
l, err := net.ListenPacket("udp", fmt.Sprintf("%v:0", ip))
if err != nil {
panic(err)
}
tc.listeners = append(tc.listeners, l)
return l
}
// close shuts down all listeners and the local node.
func (tc *conn) close() {
for _, l := range tc.listeners {
l.Close()
}
tc.localNode.Database().Close()
}
// nextReqID creates a request id.
func (tc *conn) nextReqID() []byte {
id := make([]byte, 4)
tc.idCounter++
binary.BigEndian.PutUint32(id, tc.idCounter)
return id
}
// reqresp performs a request/response interaction on the given connection.
// The request is retried if a handshake is requested.
func (tc *conn) reqresp(c net.PacketConn, req v5wire.Packet) v5wire.Packet {
reqnonce := tc.write(c, req, nil)
switch resp := tc.read(c).(type) {
case *v5wire.Whoareyou:
if resp.Nonce != reqnonce {
return readErrorf("wrong nonce %x in WHOAREYOU (want %x)", resp.Nonce[:], reqnonce[:])
}
resp.Node = tc.remote
tc.write(c, req, resp)
return tc.read(c)
default:
return resp
}
}
// findnode sends a FINDNODE request and waits for its responses.
func (tc *conn) findnode(c net.PacketConn, dists []uint) ([]*enode.Node, error) {
var (
findnode = &v5wire.Findnode{ReqID: tc.nextReqID(), Distances: dists}
reqnonce = tc.write(c, findnode, nil)
first = true
total uint8
results []*enode.Node
)
for n := 1; n > 0; {
switch resp := tc.read(c).(type) {
case *v5wire.Whoareyou:
// Handle handshake.
if resp.Nonce == reqnonce {
resp.Node = tc.remote
tc.write(c, findnode, resp)
} else {
return nil, fmt.Errorf("unexpected WHOAREYOU (nonce %x), waiting for NODES", resp.Nonce[:])
}
case *v5wire.Ping:
// Handle ping from remote.
tc.write(c, &v5wire.Pong{
ReqID: resp.ReqID,
ENRSeq: tc.localNode.Seq(),
}, nil)
case *v5wire.Nodes:
// Got NODES! Check request ID.
if !bytes.Equal(resp.ReqID, findnode.ReqID) {
return nil, fmt.Errorf("NODES response has wrong request id %x", resp.ReqID)
}
// Check total count. It should be greater than one
// and needs to be the same across all responses.
if first {
if resp.Total == 0 || resp.Total > 6 {
return nil, fmt.Errorf("invalid NODES response 'total' %d (not in (0,7))", resp.Total)
}
total = resp.Total
n = int(total) - 1
first = false
} else {
n--
if resp.Total != total {
return nil, fmt.Errorf("invalid NODES response 'total' %d (!= %d)", resp.Total, total)
}
}
// Check nodes.
nodes, err := checkRecords(resp.Nodes)
if err != nil {
return nil, fmt.Errorf("invalid node in NODES response: %v", err)
}
results = append(results, nodes...)
default:
return nil, fmt.Errorf("expected NODES, got %v", resp)
}
}
return results, nil
}
// write sends a packet on the given connection.
func (tc *conn) write(c net.PacketConn, p v5wire.Packet, challenge *v5wire.Whoareyou) v5wire.Nonce {
packet, nonce, err := tc.codec.Encode(tc.remote.ID(), tc.remoteAddr.String(), p, challenge)
if err != nil {
panic(fmt.Errorf("can't encode %v packet: %v", p.Name(), err))
}
if _, err := c.WriteTo(packet, tc.remoteAddr); err != nil {
tc.logf("Can't send %s: %v", p.Name(), err)
} else {
tc.logf(">> %s", p.Name())
}
return nonce
}
// read waits for an incoming packet on the given connection.
func (tc *conn) read(c net.PacketConn) v5wire.Packet {
buf := make([]byte, 1280)
if err := c.SetReadDeadline(time.Now().Add(waitTime)); err != nil {
return &readError{err}
}
n, fromAddr, err := c.ReadFrom(buf)
if err != nil {
return &readError{err}
}
_, _, p, err := tc.codec.Decode(buf[:n], fromAddr.String())
if err != nil {
return &readError{err}
}
tc.logf("<< %s", p.Name())
return p
}
// logf prints to the test log.
func (tc *conn) logf(format string, args ...interface{}) {
if tc.log != nil {
tc.log.Logf("(%s) %s", tc.localNode.ID().TerminalString(), fmt.Sprintf(format, args...))
}
}
func laddr(c net.PacketConn) *net.UDPAddr {
return c.LocalAddr().(*net.UDPAddr)
}
func checkRecords(records []*enr.Record) ([]*enode.Node, error) {
nodes := make([]*enode.Node, len(records))
for i := range records {
n, err := enode.New(enode.ValidSchemes, records[i])
if err != nil {
return nil, err
}
nodes[i] = n
}
return nodes, nil
}
func containsUint(ints []uint, x uint) bool {
for i := range ints {
if ints[i] == x {
return true
}
}
return false
}