Official Go implementation of the Ethereum protocol
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go-ethereum/cmd/devp2p/internal/v5test/framework.go

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// 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
}