package main import ( "bytes" "encoding/binary" "math/rand" "sync/atomic" "time" ) /* 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 (called by sequential receiver) */ func (peer *Peer) KeepKeyFreshReceiving() { if peer.timer.sendLastMinuteHandshake { 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.signal.handshakeBegin.Send() peer.timer.sendLastMinuteHandshake = true } } /* Queues a keep-alive if no packets are queued for peer */ func (peer *Peer) SendKeepAlive() bool { elem := peer.device.NewOutboundElement() elem.packet = nil if len(peer.queue.nonce) == 0 { select { case peer.queue.nonce <- elem: return true default: return false } } return true } /* Event: * Sent non-empty (authenticated) transport message */ func (peer *Peer) TimerDataSent() { peer.timer.keepalivePassive.Stop() if peer.timer.newHandshake.Pending() { peer.timer.newHandshake.Reset(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 = true } } /* Event: * Any (authenticated) packet received */ func (peer *Peer) TimerAnyAuthenticatedPacketReceived() { peer.timer.newHandshake.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() { atomic.StoreInt64( &peer.stats.lastHandshakeNano, time.Now().UnixNano(), ) peer.signal.handshakeCompleted.Send() peer.device.log.Info.Println("Negotiated new handshake for", peer.String()) } /* 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) } func (peer *Peer) RoutineTimerHandler() { device := peer.device logInfo := device.log.Info logDebug := device.log.Debug logDebug.Println("Routine, timer handler, started for peer", peer.String()) for { select { /* timers */ // keep-alive case <-peer.timer.keepalivePersistent.Wait(): interval := atomic.LoadUint64(&peer.persistentKeepaliveInterval) if interval > 0 { logDebug.Println("Sending keep-alive to", peer.String()) peer.SendKeepAlive() } case <-peer.timer.keepalivePassive.Wait(): logDebug.Println("Sending keep-alive to", peer.String()) peer.SendKeepAlive() if peer.timer.needAnotherKeepalive { peer.timer.keepalivePassive.Reset(KeepaliveTimeout) peer.timer.needAnotherKeepalive = false } // clear key material timer case <-peer.timer.zeroAllKeys.Wait(): logDebug.Println("Clearing all key material for", peer.String()) 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.localIndex = 0 setZero(hs.localEphemeral[:]) setZero(hs.remoteEphemeral[:]) setZero(hs.chainKey[:]) setZero(hs.hash[:]) hs.mutex.Unlock() // handshake timers case <-peer.timer.newHandshake.Wait(): logInfo.Println("Retrying handshake with", peer.String()) 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( "Failed to send handshake to peer:", peer.String()) } case <-peer.timer.handshakeDeadline.Wait(): // clear all queued packets and stop keep-alive logInfo.Println( "Handshake negotiation timed out for:", peer.String()) peer.signal.flushNonceQueue.Send() peer.timer.keepalivePersistent.Stop() peer.signal.handshakeBegin.Enable() /* signals */ case <-peer.signal.stop.Wait(): return case <-peer.signal.handshakeBegin.Wait(): peer.signal.handshakeBegin.Disable() err := peer.sendNewHandshake() if err != nil { logInfo.Println( "Failed to send handshake to peer:", peer.String()) } peer.timer.handshakeDeadline.Reset(RekeyAttemptTime) case <-peer.signal.handshakeCompleted.Wait(): logInfo.Println( "Handshake completed for:", peer.String()) peer.timer.handshakeTimeout.Stop() peer.timer.handshakeDeadline.Stop() peer.signal.handshakeBegin.Enable() } } } /* 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 err = peer.SendBuffer(packet) if err == nil { peer.TimerAnyAuthenticatedPacketTraversal() peer.signal.handshakeCompleted.Enable() } // set timeout jitter := time.Millisecond * time.Duration(rand.Uint32()%334) peer.timer.handshakeTimeout.Reset(RekeyTimeout + jitter) return err }