wireguard-go/peer.go
2018-02-04 16:46:24 +01:00

295 lines
6.6 KiB
Go

package main
import (
"encoding/base64"
"errors"
"fmt"
"sync"
"time"
)
const (
PeerRoutineNumber = 4
)
type Peer struct {
isRunning AtomicBool
mutex sync.RWMutex
persistentKeepaliveInterval uint64
keyPairs KeyPairs
handshake Handshake
device *Device
endpoint Endpoint
stats struct {
txBytes uint64 // bytes send to peer (endpoint)
rxBytes uint64 // bytes received from peer
lastHandshakeNano int64 // nano seconds since epoch
}
time struct {
mutex sync.RWMutex
lastSend time.Time // last send message
lastHandshake time.Time // last completed handshake
nextKeepalive time.Time
}
signal struct {
newKeyPair Signal // size 1, new key pair was generated
handshakeCompleted Signal // size 1, handshake completed
handshakeBegin Signal // size 1, begin new handshake begin
flushNonceQueue Signal // size 1, empty queued packets
messageSend Signal // size 1, message was send to peer
messageReceived Signal // size 1, authenticated message recv
}
timer struct {
// state related to WireGuard timers
keepalivePersistent Timer // set for persistent keep-alive
keepalivePassive Timer // set upon receiving messages
zeroAllKeys Timer // zero all key material
handshakeNew Timer // begin a new handshake (stale)
handshakeDeadline Timer // complete handshake timeout
handshakeTimeout Timer // current handshake message timeout
sendLastMinuteHandshake bool
needAnotherKeepalive bool
}
queue struct {
nonce chan *QueueOutboundElement // nonce / pre-handshake queue
outbound chan *QueueOutboundElement // sequential ordering of work
inbound chan *QueueInboundElement // sequential ordering of work
}
routines struct {
mutex sync.Mutex // held when stopping / starting routines
starting sync.WaitGroup // routines pending start
stopping sync.WaitGroup // routines pending stop
stop Signal // size 0, stop all go-routines in peer
}
mac CookieGenerator
}
func (device *Device) NewPeer(pk NoisePublicKey) (*Peer, error) {
if device.isClosed.Get() {
return nil, errors.New("Device closed")
}
// lock resources
device.state.mutex.Lock()
defer device.state.mutex.Unlock()
device.noise.mutex.RLock()
defer device.noise.mutex.RUnlock()
device.peers.mutex.Lock()
defer device.peers.mutex.Unlock()
// check if over limit
if len(device.peers.keyMap) >= MaxPeers {
return nil, errors.New("Too many peers")
}
// create peer
peer := new(Peer)
peer.mutex.Lock()
defer peer.mutex.Unlock()
peer.mac.Init(pk)
peer.device = device
peer.isRunning.Set(false)
peer.timer.zeroAllKeys = NewTimer()
peer.timer.keepalivePersistent = NewTimer()
peer.timer.keepalivePassive = NewTimer()
peer.timer.handshakeNew = NewTimer()
peer.timer.handshakeDeadline = NewTimer()
peer.timer.handshakeTimeout = NewTimer()
// map public key
_, ok := device.peers.keyMap[pk]
if ok {
return nil, errors.New("Adding existing peer")
}
device.peers.keyMap[pk] = peer
// pre-compute DH
handshake := &peer.handshake
handshake.mutex.Lock()
handshake.remoteStatic = pk
handshake.precomputedStaticStatic = device.noise.privateKey.sharedSecret(pk)
handshake.mutex.Unlock()
// reset endpoint
peer.endpoint = nil
// prepare signaling & routines
peer.routines.mutex.Lock()
peer.routines.stop = NewSignal()
peer.routines.mutex.Unlock()
// start peer
if peer.device.isUp.Get() {
peer.Start()
}
return peer, nil
}
func (peer *Peer) SendBuffer(buffer []byte) error {
peer.device.net.mutex.RLock()
defer peer.device.net.mutex.RUnlock()
if peer.device.net.bind == nil {
return errors.New("No bind")
}
peer.mutex.RLock()
defer peer.mutex.RUnlock()
if peer.endpoint == nil {
return errors.New("No known endpoint for peer")
}
return peer.device.net.bind.Send(buffer, peer.endpoint)
}
/* Returns a short string identifier for logging
*/
func (peer *Peer) String() string {
if peer.endpoint == nil {
return fmt.Sprintf(
"peer(unknown %s)",
base64.StdEncoding.EncodeToString(peer.handshake.remoteStatic[:]),
)
}
return fmt.Sprintf(
"peer(%s %s)",
peer.endpoint.DstToString(),
base64.StdEncoding.EncodeToString(peer.handshake.remoteStatic[:]),
)
}
func (peer *Peer) Start() {
// should never start a peer on a closed device
if peer.device.isClosed.Get() {
return
}
// prevent simultaneous start/stop operations
peer.routines.mutex.Lock()
defer peer.routines.mutex.Unlock()
if peer.isRunning.Get() {
return
}
peer.device.log.Debug.Println("Starting:", peer.String())
// sanity check : these should be 0
peer.routines.starting.Wait()
peer.routines.stopping.Wait()
// prepare queues and signals
peer.signal.newKeyPair = NewSignal()
peer.signal.handshakeBegin = NewSignal()
peer.signal.handshakeCompleted = NewSignal()
peer.signal.flushNonceQueue = NewSignal()
peer.queue.nonce = make(chan *QueueOutboundElement, QueueOutboundSize)
peer.queue.outbound = make(chan *QueueOutboundElement, QueueOutboundSize)
peer.queue.inbound = make(chan *QueueInboundElement, QueueInboundSize)
peer.routines.stop = NewSignal()
peer.isRunning.Set(true)
// wait for routines to start
peer.routines.starting.Add(PeerRoutineNumber)
peer.routines.stopping.Add(PeerRoutineNumber)
go peer.RoutineNonce()
go peer.RoutineTimerHandler()
go peer.RoutineSequentialSender()
go peer.RoutineSequentialReceiver()
peer.routines.starting.Wait()
peer.isRunning.Set(true)
}
func (peer *Peer) Stop() {
// prevent simultaneous start/stop operations
peer.routines.mutex.Lock()
defer peer.routines.mutex.Unlock()
if !peer.isRunning.Swap(false) {
return
}
device := peer.device
device.log.Debug.Println("Stopping:", peer.String())
// stop & wait for ongoing peer routines
peer.routines.stop.Broadcast()
peer.routines.starting.Wait()
peer.routines.stopping.Wait()
// stop timers
peer.timer.keepalivePersistent.Stop()
peer.timer.keepalivePassive.Stop()
peer.timer.zeroAllKeys.Stop()
peer.timer.handshakeNew.Stop()
peer.timer.handshakeDeadline.Stop()
peer.timer.handshakeTimeout.Stop()
// close queues
close(peer.queue.nonce)
close(peer.queue.outbound)
close(peer.queue.inbound)
// clear key pairs
kp := &peer.keyPairs
kp.mutex.Lock()
device.DeleteKeyPair(kp.previous)
device.DeleteKeyPair(kp.current)
device.DeleteKeyPair(kp.next)
kp.previous = nil
kp.current = nil
kp.next = nil
kp.mutex.Unlock()
// clear handshake state
hs := &peer.handshake
hs.mutex.Lock()
device.indices.Delete(hs.localIndex)
hs.Clear()
hs.mutex.Unlock()
}