Official Go implementation of the Ethereum protocol
You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
go-ethereum/p2p/transport.go

184 lines
5.6 KiB

// Copyright 2020 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library 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 Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package p2p
import (
"bytes"
"crypto/ecdsa"
"errors"
"fmt"
"io"
"net"
"sync"
"time"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/common/bitutil"
"github.com/ethereum/go-ethereum/metrics"
"github.com/ethereum/go-ethereum/p2p/rlpx"
"github.com/ethereum/go-ethereum/rlp"
)
const (
// total timeout for encryption handshake and protocol
// handshake in both directions.
handshakeTimeout = 5 * time.Second
// This is the timeout for sending the disconnect reason.
// This is shorter than the usual timeout because we don't want
// to wait if the connection is known to be bad anyway.
discWriteTimeout = 1 * time.Second
)
// rlpxTransport is the transport used by actual (non-test) connections.
// It wraps an RLPx connection with locks and read/write deadlines.
type rlpxTransport struct {
rmu, wmu sync.Mutex
wbuf bytes.Buffer
conn *rlpx.Conn
}
func newRLPX(conn net.Conn, dialDest *ecdsa.PublicKey) transport {
return &rlpxTransport{conn: rlpx.NewConn(conn, dialDest)}
}
func (t *rlpxTransport) ReadMsg() (Msg, error) {
t.rmu.Lock()
defer t.rmu.Unlock()
var msg Msg
t.conn.SetReadDeadline(time.Now().Add(frameReadTimeout))
code, data, wireSize, err := t.conn.Read()
if err == nil {
// Protocol messages are dispatched to subprotocol handlers asynchronously,
// but package rlpx may reuse the returned 'data' buffer on the next call
// to Read. Copy the message data to avoid this being an issue.
data = common.CopyBytes(data)
msg = Msg{
ReceivedAt: time.Now(),
Code: code,
Size: uint32(len(data)),
meterSize: uint32(wireSize),
Payload: bytes.NewReader(data),
}
}
return msg, err
}
func (t *rlpxTransport) WriteMsg(msg Msg) error {
t.wmu.Lock()
defer t.wmu.Unlock()
// Copy message data to write buffer.
t.wbuf.Reset()
if _, err := io.CopyN(&t.wbuf, msg.Payload, int64(msg.Size)); err != nil {
return err
}
// Write the message.
t.conn.SetWriteDeadline(time.Now().Add(frameWriteTimeout))
size, err := t.conn.Write(msg.Code, t.wbuf.Bytes())
if err != nil {
return err
}
// Set metrics.
msg.meterSize = size
if metrics.Enabled && msg.meterCap.Name != "" { // don't meter non-subprotocol messages
m := fmt.Sprintf("%s/%s/%d/%#02x", egressMeterName, msg.meterCap.Name, msg.meterCap.Version, msg.meterCode)
metrics.GetOrRegisterMeter(m, nil).Mark(int64(msg.meterSize))
metrics.GetOrRegisterMeter(m+"/packets", nil).Mark(1)
}
return nil
}
func (t *rlpxTransport) close(err error) {
t.wmu.Lock()
defer t.wmu.Unlock()
// Tell the remote end why we're disconnecting if possible.
// We only bother doing this if the underlying connection supports
// setting a timeout tough.
if t.conn != nil {
if r, ok := err.(DiscReason); ok && r != DiscNetworkError {
deadline := time.Now().Add(discWriteTimeout)
if err := t.conn.SetWriteDeadline(deadline); err == nil {
// Connection supports write deadline.
t.wbuf.Reset()
rlp.Encode(&t.wbuf, []DiscReason{r})
t.conn.Write(discMsg, t.wbuf.Bytes())
}
}
}
t.conn.Close()
}
func (t *rlpxTransport) doEncHandshake(prv *ecdsa.PrivateKey) (*ecdsa.PublicKey, error) {
t.conn.SetDeadline(time.Now().Add(handshakeTimeout))
return t.conn.Handshake(prv)
}
func (t *rlpxTransport) doProtoHandshake(our *protoHandshake) (their *protoHandshake, err error) {
// Writing our handshake happens concurrently, we prefer
// returning the handshake read error. If the remote side
// disconnects us early with a valid reason, we should return it
// as the error so it can be tracked elsewhere.
werr := make(chan error, 1)
go func() { werr <- Send(t, handshakeMsg, our) }()
if their, err = readProtocolHandshake(t); err != nil {
<-werr // make sure the write terminates too
return nil, err
}
if err := <-werr; err != nil {
return nil, fmt.Errorf("write error: %v", err)
}
// If the protocol version supports Snappy encoding, upgrade immediately
t.conn.SetSnappy(their.Version >= snappyProtocolVersion)
return their, nil
}
func readProtocolHandshake(rw MsgReader) (*protoHandshake, error) {
msg, err := rw.ReadMsg()
if err != nil {
return nil, err
}
if msg.Size > baseProtocolMaxMsgSize {
return nil, errors.New("message too big")
}
if msg.Code == discMsg {
// Disconnect before protocol handshake is valid according to the
// spec and we send it ourself if the post-handshake checks fail.
// We can't return the reason directly, though, because it is echoed
// back otherwise. Wrap it in a string instead.
var reason [1]DiscReason
rlp.Decode(msg.Payload, &reason)
return nil, reason[0]
}
if msg.Code != handshakeMsg {
return nil, fmt.Errorf("expected handshake, got %x", msg.Code)
}
var hs protoHandshake
if err := msg.Decode(&hs); err != nil {
return nil, err
}
if len(hs.ID) != 64 || !bitutil.TestBytes(hs.ID) {
return nil, DiscInvalidIdentity
}
return &hs, nil
}