EtherGuard-VPN/timers.go

348 lines
7.5 KiB
Go
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2018-02-11 19:02:50 +01:00
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.signal.handshakeBegin.Send()
}
if kp.isInitiator && time.Now().Sub(kp.created) > RekeyAfterTime {
peer.signal.handshakeBegin.Send()
}
}
/* 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() {
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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)
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peer.signal.handshakeBegin.Send()
}
}
/* 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
}
}
/* Event:
* Sent non-empty (authenticated) transport message
*/
func (peer *Peer) TimerDataSent() {
peer.timer.keepalivePassive.Stop()
peer.timer.handshakeNew.Start(NewHandshakeTime)
}
/* Event:
* Received non-empty (authenticated) transport message
*
* Action:
* Set a timer to confirm the message using a keep-alive (if not already set)
*/
func (peer *Peer) TimerDataReceived() {
if !peer.timer.keepalivePassive.Start(KeepaliveTimeout) {
peer.timer.needAnotherKeepalive.Set(true)
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}
}
/* Event:
* Any (authenticated) packet received
*/
func (peer *Peer) TimerAnyAuthenticatedPacketReceived() {
peer.timer.handshakeNew.Stop()
}
/* Event:
* Any authenticated packet send / received.
*
* Action:
* Push persistent keep-alive into the future
*/
func (peer *Peer) TimerAnyAuthenticatedPacketTraversal() {
interval := atomic.LoadUint64(&peer.persistentKeepaliveInterval)
if interval > 0 {
duration := time.Duration(interval) * time.Second
peer.timer.keepalivePersistent.Reset(duration)
}
}
/* Called after successfully completing a handshake.
* i.e. after:
*
* - Valid handshake response
* - First transport message under the "next" key
*/
func (peer *Peer) TimerHandshakeComplete() {
peer.signal.handshakeCompleted.Send()
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peer.device.log.Info.Println(peer.String(), ": New handshake completed")
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}
/* 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.timer.zeroAllKeys.Reset(RejectAfterTime * 3)
}
/* Sends a new handshake initiation message to the peer (endpoint)
*/
func (peer *Peer) sendNewHandshake() error {
// temporarily disable the handshake complete signal
peer.signal.handshakeCompleted.Disable()
// 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.TimerAnyAuthenticatedPacketTraversal()
err = peer.SendBuffer(packet)
if err == nil {
peer.signal.handshakeCompleted.Enable()
}
// set timeout
jitter := time.Millisecond * time.Duration(rand.Uint32()%334)
peer.timer.keepalivePassive.Stop()
peer.timer.handshakeTimeout.Reset(RekeyTimeout + jitter)
return err
}
func (peer *Peer) RoutineTimerHandler() {
defer peer.routines.stopping.Done()
device := peer.device
logInfo := device.log.Info
logDebug := device.log.Debug
logDebug.Println("Routine, timer handler, started for peer", peer.String())
// reset all timers
peer.timer.keepalivePassive.Stop()
peer.timer.handshakeDeadline.Stop()
peer.timer.handshakeTimeout.Stop()
peer.timer.handshakeNew.Stop()
peer.timer.zeroAllKeys.Stop()
interval := atomic.LoadUint64(&peer.persistentKeepaliveInterval)
if interval > 0 {
duration := time.Duration(interval) * time.Second
peer.timer.keepalivePersistent.Reset(duration)
}
// signal synchronised setup complete
peer.routines.starting.Done()
// handle timer events
for {
select {
/* stopping */
case <-peer.routines.stop.Wait():
return
/* timers */
// keep-alive
case <-peer.timer.keepalivePersistent.Wait():
interval := atomic.LoadUint64(&peer.persistentKeepaliveInterval)
if interval > 0 {
logDebug.Println(peer.String(), ": Send keep-alive (persistent)")
peer.timer.keepalivePassive.Stop()
peer.SendKeepAlive()
}
case <-peer.timer.keepalivePassive.Wait():
logDebug.Println(peer.String(), ": Send keep-alive (passive)")
peer.SendKeepAlive()
if peer.timer.needAnotherKeepalive.Swap(false) {
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peer.timer.keepalivePassive.Reset(KeepaliveTimeout)
}
// clear key material timer
case <-peer.timer.zeroAllKeys.Wait():
logDebug.Println(peer.String(), ": 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 <-peer.timer.handshakeNew.Wait():
logInfo.Println(peer.String(), ": Retrying handshake (timer event)")
peer.signal.handshakeBegin.Send()
case <-peer.timer.handshakeTimeout.Wait():
// 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()
if err != nil {
logInfo.Println(peer.String(), ": Failed to send handshake initiation", err)
} else {
logDebug.Println(peer.String(), ": Send handshake initiation (subsequent)")
}
case <-peer.timer.handshakeDeadline.Wait():
// clear all queued packets and stop keep-alive
logInfo.Println(peer.String(), ": Handshake negotiation timed-out")
peer.signal.flushNonceQueue.Send()
peer.timer.keepalivePersistent.Stop()
peer.signal.handshakeBegin.Enable()
/* signals */
case <-peer.signal.handshakeBegin.Wait():
peer.signal.handshakeBegin.Disable()
err := peer.sendNewHandshake()
if err != nil {
logInfo.Println(peer.String(), ": Failed to send handshake initiation", err)
} else {
logDebug.Println(peer.String(), ": Send handshake initiation (initial)")
}
peer.timer.handshakeDeadline.Reset(RekeyAttemptTime)
case <-peer.signal.handshakeCompleted.Wait():
logInfo.Println(peer.String(), ": Handshake completed")
atomic.StoreInt64(
&peer.stats.lastHandshakeNano,
time.Now().UnixNano(),
)
peer.timer.handshakeTimeout.Stop()
peer.timer.handshakeDeadline.Stop()
peer.signal.handshakeBegin.Enable()
peer.timer.sendLastMinuteHandshake.Set(false)
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}
}
}