p2p: move rlpx into separate package (ethereum#21464)

This change moves the RLPx protocol implementation into a separate package,
p2p/rlpx. The new package can be used to establish RLPx connections for
protocol testing purposes.

Co-authored-by: Felix Lange <[email protected]>

cmd/devp2p/main.go

@@ -63,6 +63,7 @@ func init() {
 		discv5Command,
 		dnsCommand,
 		nodesetCommand,
+		rlpxCommand,
 	}
 }
 

cmd/devp2p/rlpxcmd.go

@@ -0,0 +1,94 @@
+// 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 main
+
+import (
+	"fmt"
+	"net"
+
+	"github.com/ethereum/go-ethereum/common/hexutil"
+	"github.com/ethereum/go-ethereum/crypto"
+	"github.com/ethereum/go-ethereum/p2p"
+	"github.com/ethereum/go-ethereum/p2p/rlpx"
+	"github.com/ethereum/go-ethereum/rlp"
+	"gopkg.in/urfave/cli.v1"
+)
+
+var (
+	rlpxCommand = cli.Command{
+		Name:  "rlpx",
+		Usage: "RLPx Commands",
+		Subcommands: []cli.Command{
+			rlpxPingCommand,
+		},
+	}
+	rlpxPingCommand = cli.Command{
+		Name:      "ping",
+		Usage:     "Perform a RLPx handshake",
+		ArgsUsage: "<node>",
+		Action:    rlpxPing,
+	}
+)
+
+func rlpxPing(ctx *cli.Context) error {
+	n := getNodeArg(ctx)
+
+	fd, err := net.Dial("tcp", fmt.Sprintf("%v:%d", n.IP(), n.TCP()))
+	if err != nil {
+		return err
+	}
+	conn := rlpx.NewConn(fd, n.Pubkey())
+
+	ourKey, _ := crypto.GenerateKey()
+	_, err = conn.Handshake(ourKey)
+	if err != nil {
+		return err
+	}
+
+	code, data, _, err := conn.Read()
+	if err != nil {
+		return err
+	}
+	switch code {
+	case 0:
+		var h devp2pHandshake
+		if err := rlp.DecodeBytes(data, &h); err != nil {
+			return fmt.Errorf("invalid handshake: %v", err)
+		}
+		fmt.Printf("%+v\n", h)
+	case 1:
+		var msg []p2p.DiscReason
+		if rlp.DecodeBytes(data, &msg); len(msg) == 0 {
+			return fmt.Errorf("invalid disconnect message")
+		}
+		return fmt.Errorf("received disconnect message: %v", msg[0])
+	default:
+		return fmt.Errorf("invalid message code %d, expected handshake (code zero)", code)
+	}
+	return nil
+}
+
+// devp2pHandshake is the RLP structure of the devp2p protocol handshake.
+type devp2pHandshake struct {
+	Version    uint64
+	Name       string
+	Caps       []p2p.Cap
+	ListenPort uint64
+	ID         hexutil.Bytes // secp256k1 public key
+	// Ignore additional fields (for forward compatibility).
+	Rest []rlp.RawValue `rlp:"tail"`
+}

p2p/message_test.go

@@ -18,11 +18,9 @@ package p2p
 
 import (
 	"bytes"
-	"encoding/hex"
 	"fmt"
 	"io"
 	"runtime"
-	"strings"
 	"testing"
 	"time"
 )
@@ -141,12 +139,3 @@ func TestEOFSignal(t *testing.T) {
 	default:
 	}
 }
-
-func unhex(str string) []byte {
-	r := strings.NewReplacer("\t", "", " ", "", "\n", "")
-	b, err := hex.DecodeString(r.Replace(str))
-	if err != nil {
-		panic(fmt.Sprintf("invalid hex string: %q", str))
-	}
-	return b
-}

p2p/peer_test.go

@@ -86,9 +86,15 @@ func newNode(id enode.ID, addr string) *enode.Node {
 }
 
 func testPeer(protos []Protocol) (func(), *conn, *Peer, <-chan error) {
-	fd1, fd2 := net.Pipe()
-	c1 := &conn{fd: fd1, node: newNode(randomID(), ""), transport: newTestTransport(&newkey().PublicKey, fd1)}
-	c2 := &conn{fd: fd2, node: newNode(randomID(), ""), transport: newTestTransport(&newkey().PublicKey, fd2)}
+	var (
+		fd1, fd2   = net.Pipe()
+		key1, key2 = newkey(), newkey()
+		t1         = newTestTransport(&key2.PublicKey, fd1, nil)
+		t2         = newTestTransport(&key1.PublicKey, fd2, &key1.PublicKey)
+	)
+
+	c1 := &conn{fd: fd1, node: newNode(uintID(1), ""), transport: t1}
+	c2 := &conn{fd: fd2, node: newNode(uintID(2), ""), transport: t2}
 	for _, p := range protos {
 		c1.caps = append(c1.caps, p.cap())
 		c2.caps = append(c2.caps, p.cap())
@@ -173,9 +179,12 @@ func TestPeerPing(t *testing.T) {
 	}
 }
 
+// This test checks that a disconnect message sent by a peer is returned
+// as the error from Peer.run.
 func TestPeerDisconnect(t *testing.T) {
 	closer, rw, _, disc := testPeer(nil)
 	defer closer()
+
 	if err := SendItems(rw, discMsg, DiscQuitting); err != nil {
 		t.Fatal(err)
 	}