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network: rework peer handshaking, fix #458

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This allows to start handshaking from both client and server (mainnet/testnet
nodes were seen to not care about string ordering for it), but still maintains
some sane checks in the process. It also makes functions thread-safe because
we have two goroutines servicing read and write side of the Peer connection,
so they can clash on access to the struct fields.

Add a test for it also.
This commit is contained in:
Roman Khimov 2019-11-06 11:06:00 +03:00
parent e859e03240
commit ec76ed23a5
3 changed files with 117 additions and 46 deletions
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53
pkg/network/tcp_peer.go
View file

@ -12,13 +12,11 @@ import (
type handShakeStage uint8
//go:generate stringer -type=handShakeStage
const (
nothingDone handShakeStage = 0
versionSent handShakeStage = 1
versionReceived handShakeStage = 2
verAckSent handShakeStage = 3
verAckReceived handShakeStage = 4
versionSent handShakeStage = 1 << iota
versionReceived
verAckSent
verAckReceived
)
var (
@ -34,6 +32,7 @@ type TCPPeer struct {
// The version of the peer.
version *payload.Version
lock sync.RWMutex
handShake handShakeStage
done chan error
@ -71,39 +70,50 @@ func (p *TCPPeer) writeMsg(msg *Message) error {
// Handshaked returns status of the handshake, whether it's completed or not.
func (p *TCPPeer) Handshaked() bool {
return p.handShake == verAckReceived
p.lock.RLock()
defer p.lock.RUnlock()
return p.handShake == (verAckReceived | verAckSent | versionReceived | versionSent)
}
// SendVersion checks for the handshake state and sends a message to the peer.
func (p *TCPPeer) SendVersion(msg *Message) error {
if p.handShake != nothingDone {
return fmt.Errorf("invalid handshake: tried to send Version in %s state", p.handShake.String())
p.lock.Lock()
defer p.lock.Unlock()
if p.handShake&versionSent != 0 {
return errors.New("invalid handshake: already sent Version")
}
err := p.writeMsg(msg)
if err == nil {
p.handShake = versionSent
p.handShake |= versionSent
}
return err
}
// HandleVersion checks for the handshake state and version message contents.
func (p *TCPPeer) HandleVersion(version *payload.Version) error {
if p.handShake != versionSent {
return fmt.Errorf("invalid handshake: received Version in %s state", p.handShake.String())
p.lock.Lock()
defer p.lock.Unlock()
if p.handShake&versionReceived != 0 {
return errors.New("invalid handshake: already received Version")
}
p.version = version
p.handShake = versionReceived
p.handShake |= versionReceived
return nil
}
// SendVersionAck checks for the handshake state and sends a message to the peer.
func (p *TCPPeer) SendVersionAck(msg *Message) error {
if p.handShake != versionReceived {
return fmt.Errorf("invalid handshake: tried to send VersionAck in %s state", p.handShake.String())
p.lock.Lock()
defer p.lock.Unlock()
if p.handShake&versionReceived == 0 {
return errors.New("invalid handshake: tried to send VersionAck, but no version received yet")
}
if p.handShake&verAckSent != 0 {
return errors.New("invalid handshake: already sent VersionAck")
}
err := p.writeMsg(msg)
if err == nil {
p.handShake = verAckSent
p.handShake |= verAckSent
}
return err
}
@ -111,10 +121,15 @@ func (p *TCPPeer) SendVersionAck(msg *Message) error {
// HandleVersionAck checks handshake sequence correctness when VerAck message
// is received.
func (p *TCPPeer) HandleVersionAck() error {
if p.handShake != verAckSent {
return fmt.Errorf("invalid handshake: received VersionAck in %s state", p.handShake.String())
p.lock.Lock()
defer p.lock.Unlock()
if p.handShake&versionSent == 0 {
return errors.New("invalid handshake: received VersionAck, but no version sent yet")
}
p.handShake = verAckReceived
if p.handShake&verAckReceived != 0 {
return errors.New("invalid handshake: already received VersionAck")
}
p.handShake |= verAckReceived
return nil
}