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- // Copyright 2015 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"
- "fmt"
- "io"
- "net"
- "sync"
- "time"
- "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 {
- 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, fmt.Errorf("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
- }
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