wireguard-go/timers.go
Mathias Hall-Andersen 8ba28be732 Use Int32n for jitter
2018-05-05 04:42:17 +02:00

363 lines
7.5 KiB
Go

/* SPDX-License-Identifier: GPL-2.0
*
* Copyright (C) 2017-2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
*/
package main
import (
"bytes"
"encoding/binary"
"math/rand"
"sync/atomic"
"time"
)
/* NOTE:
* Notion of validity
*/
/* Called when a new authenticated message has been send
*
*/
func (peer *Peer) KeepKeyFreshSending() {
kp := peer.keyPairs.Current()
if kp == nil {
return
}
nonce := atomic.LoadUint64(&kp.sendNonce)
if nonce > RekeyAfterMessages {
peer.event.handshakeBegin.Fire()
}
if kp.isInitiator && time.Now().Sub(kp.created) > RekeyAfterTime {
peer.event.handshakeBegin.Fire()
}
}
/* Called when a new authenticated message has been received
*
* NOTE: Not thread safe, but called by sequential receiver!
*/
func (peer *Peer) KeepKeyFreshReceiving() {
if peer.timer.sendLastMinuteHandshake.Get() {
return
}
kp := peer.keyPairs.Current()
if kp == nil {
return
}
if !kp.isInitiator {
return
}
nonce := atomic.LoadUint64(&kp.sendNonce)
send := nonce > RekeyAfterMessages || time.Now().Sub(kp.created) > RekeyAfterTimeReceiving
if send {
// do a last minute attempt at initiating a new handshake
peer.timer.sendLastMinuteHandshake.Set(true)
peer.event.handshakeBegin.Fire()
}
}
/* Queues a keep-alive if no packets are queued for peer
*/
func (peer *Peer) SendKeepAlive() bool {
if len(peer.queue.nonce) != 0 {
return false
}
elem := peer.device.NewOutboundElement()
elem.packet = nil
select {
case peer.queue.nonce <- elem:
return true
default:
return false
}
}
/* Called after successfully completing a handshake.
* i.e. after:
*
* - Valid handshake response
* - First transport message under the "next" key
*/
// peer.device.log.Info.Println(peer, ": New handshake completed")
/* Event:
* An ephemeral key is generated
*
* i.e. after:
*
* CreateMessageInitiation
* CreateMessageResponse
*
* Action:
* Schedule the deletion of all key material
* upon failure to complete a handshake
*/
func (peer *Peer) TimerEphemeralKeyCreated() {
peer.event.ephemeralKeyCreated.Fire()
// peer.timer.zeroAllKeys.Reset(RejectAfterTime * 3)
}
/* Sends a new handshake initiation message to the peer (endpoint)
*/
func (peer *Peer) sendNewHandshake() error {
// create initiation message
msg, err := peer.device.CreateMessageInitiation(peer)
if err != nil {
return err
}
// marshal handshake message
var buff [MessageInitiationSize]byte
writer := bytes.NewBuffer(buff[:0])
binary.Write(writer, binary.LittleEndian, msg)
packet := writer.Bytes()
peer.mac.AddMacs(packet)
// send to endpoint
peer.event.anyAuthenticatedPacketTraversal.Fire()
return peer.SendBuffer(packet)
}
func newTimer() *time.Timer {
timer := time.NewTimer(time.Hour)
timer.Stop()
return timer
}
func (peer *Peer) RoutineTimerHandler() {
device := peer.device
logInfo := device.log.Info
logDebug := device.log.Debug
defer func() {
logDebug.Println(peer, ": Routine: timer handler - stopped")
peer.routines.stopping.Done()
}()
logDebug.Println(peer, ": Routine: timer handler - started")
// reset all timers
enableHandshake := true
pendingHandshakeNew := false
pendingKeepalivePassive := false
timerKeepalivePassive := newTimer()
timerHandshakeDeadline := newTimer()
timerHandshakeTimeout := newTimer()
timerHandshakeNew := newTimer()
timerZeroAllKeys := newTimer()
timerKeepalivePersistent := newTimer()
interval := peer.persistentKeepaliveInterval
if interval > 0 {
duration := time.Duration(interval) * time.Second
timerKeepalivePersistent.Reset(duration)
}
// signal synchronised setup complete
peer.routines.starting.Done()
// handle timer events
for {
select {
/* stopping */
case <-peer.routines.stop.Wait():
return
/* events */
case <-peer.event.dataSent.C:
timerKeepalivePassive.Stop()
if !pendingHandshakeNew {
timerHandshakeNew.Reset(NewHandshakeTime)
}
case <-peer.event.dataReceived.C:
if pendingKeepalivePassive {
peer.timer.needAnotherKeepalive.Set(true) // TODO: make local
} else {
timerKeepalivePassive.Reset(KeepaliveTimeout)
}
case <-peer.event.anyAuthenticatedPacketTraversal.C:
interval := peer.persistentKeepaliveInterval
if interval > 0 {
duration := time.Duration(interval) * time.Second
timerKeepalivePersistent.Reset(duration)
}
case <-peer.event.handshakeBegin.C:
if !enableHandshake {
continue
}
logDebug.Println(peer, ": Event, Handshake Begin")
err := peer.sendNewHandshake()
// set timeout
jitter := time.Millisecond * time.Duration(rand.Int31n(334))
timerKeepalivePassive.Stop()
timerHandshakeTimeout.Reset(RekeyTimeout + jitter)
if err != nil {
logInfo.Println(peer, ": Failed to send handshake initiation", err)
} else {
logDebug.Println(peer, ": Send handshake initiation (initial)")
}
timerHandshakeDeadline.Reset(RekeyAttemptTime)
// disable further handshakes
peer.event.handshakeBegin.Clear()
enableHandshake = false
case <-peer.event.handshakeCompleted.C:
logInfo.Println(peer, ": Handshake completed")
atomic.StoreInt64(
&peer.stats.lastHandshakeNano,
time.Now().UnixNano(),
)
timerHandshakeTimeout.Stop()
timerHandshakeDeadline.Stop()
peer.timer.sendLastMinuteHandshake.Set(false)
// allow further handshakes
peer.event.handshakeBegin.Clear()
enableHandshake = true
/* timers */
// keep-alive
case <-timerKeepalivePersistent.C:
interval := peer.persistentKeepaliveInterval
if interval > 0 {
logDebug.Println(peer, ": Send keep-alive (persistent)")
timerKeepalivePassive.Stop()
peer.SendKeepAlive()
}
case <-timerKeepalivePassive.C:
logDebug.Println(peer, ": Send keep-alive (passive)")
peer.SendKeepAlive()
if peer.timer.needAnotherKeepalive.Swap(false) {
timerKeepalivePassive.Reset(KeepaliveTimeout)
}
// clear key material timer
case <-timerZeroAllKeys.C:
logDebug.Println(peer, ": Clear all key-material (timer event)")
hs := &peer.handshake
hs.mutex.Lock()
kp := &peer.keyPairs
kp.mutex.Lock()
// remove key-pairs
if kp.previous != nil {
device.DeleteKeyPair(kp.previous)
kp.previous = nil
}
if kp.current != nil {
device.DeleteKeyPair(kp.current)
kp.current = nil
}
if kp.next != nil {
device.DeleteKeyPair(kp.next)
kp.next = nil
}
kp.mutex.Unlock()
// zero out handshake
device.indices.Delete(hs.localIndex)
hs.Clear()
hs.mutex.Unlock()
// handshake timers
case <-timerHandshakeTimeout.C:
// allow new handshake to be send
enableHandshake = true
// clear source (in case this is causing problems)
peer.mutex.Lock()
if peer.endpoint != nil {
peer.endpoint.ClearSrc()
}
peer.mutex.Unlock()
// send new handshake
err := peer.sendNewHandshake()
// set timeout
jitter := time.Millisecond * time.Duration(rand.Int31n(334))
timerKeepalivePassive.Stop()
timerHandshakeTimeout.Reset(RekeyTimeout + jitter)
if err != nil {
logInfo.Println(peer, ": Failed to send handshake initiation", err)
} else {
logDebug.Println(peer, ": Send handshake initiation (subsequent)")
}
// disable further handshakes
peer.event.handshakeBegin.Clear()
enableHandshake = false
case <-timerHandshakeDeadline.C:
// clear all queued packets and stop keep-alive
logInfo.Println(peer, ": Handshake negotiation timed-out")
peer.flushNonceQueue()
signalSend(peer.signal.flushNonceQueue)
timerKeepalivePersistent.Stop()
// disable further handshakes
peer.event.handshakeBegin.Clear()
enableHandshake = true
}
}
}