308 lines
7 KiB
Go
308 lines
7 KiB
Go
/* SPDX-License-Identifier: MIT
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*
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* Copyright (C) 2017-2020 WireGuard LLC. All Rights Reserved.
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*/
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package device
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import (
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"encoding/base64"
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"errors"
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"fmt"
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"sync"
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"sync/atomic"
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"time"
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"golang.zx2c4.com/wireguard/conn"
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)
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const (
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PeerRoutineNumber = 2
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)
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type Peer struct {
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isRunning AtomicBool
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sync.RWMutex // Mostly protects endpoint, but is generally taken whenever we modify peer
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keypairs Keypairs
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handshake Handshake
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device *Device
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endpoint conn.Endpoint
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persistentKeepaliveInterval uint32 // accessed atomically
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// These fields are accessed with atomic operations, which must be
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// 64-bit aligned even on 32-bit platforms. Go guarantees that an
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// allocated struct will be 64-bit aligned. So we place
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// atomically-accessed fields up front, so that they can share in
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// this alignment before smaller fields throw it off.
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stats struct {
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txBytes uint64 // bytes send to peer (endpoint)
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rxBytes uint64 // bytes received from peer
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lastHandshakeNano int64 // nano seconds since epoch
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}
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disableRoaming bool
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timers struct {
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retransmitHandshake *Timer
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sendKeepalive *Timer
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newHandshake *Timer
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zeroKeyMaterial *Timer
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persistentKeepalive *Timer
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handshakeAttempts uint32
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needAnotherKeepalive AtomicBool
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sentLastMinuteHandshake AtomicBool
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}
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signals struct {
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newKeypairArrived chan struct{}
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flushNonceQueue chan struct{}
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}
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queue struct {
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sync.RWMutex
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nonce chan *QueueOutboundElement // nonce / pre-handshake queue
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outbound chan *QueueOutboundElement // sequential ordering of work
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inbound chan *QueueInboundElement // sequential ordering of work
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packetInNonceQueueIsAwaitingKey AtomicBool
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}
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routines struct {
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sync.Mutex // held when stopping routines
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stopping sync.WaitGroup // routines pending stop
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stop chan struct{} // size 0, stop all go routines in peer
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}
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cookieGenerator CookieGenerator
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}
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func (device *Device) NewPeer(pk NoisePublicKey) (*Peer, error) {
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if device.isClosed.Get() {
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return nil, errors.New("device closed")
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}
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// lock resources
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device.staticIdentity.RLock()
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defer device.staticIdentity.RUnlock()
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device.peers.Lock()
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defer device.peers.Unlock()
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// check if over limit
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if len(device.peers.keyMap) >= MaxPeers {
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return nil, errors.New("too many peers")
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}
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// create peer
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peer := new(Peer)
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peer.Lock()
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defer peer.Unlock()
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peer.cookieGenerator.Init(pk)
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peer.device = device
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// map public key
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_, ok := device.peers.keyMap[pk]
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if ok {
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return nil, errors.New("adding existing peer")
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}
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// pre-compute DH
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handshake := &peer.handshake
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handshake.mutex.Lock()
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handshake.precomputedStaticStatic = device.staticIdentity.privateKey.sharedSecret(pk)
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handshake.remoteStatic = pk
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handshake.mutex.Unlock()
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// reset endpoint
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peer.endpoint = nil
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// add
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device.peers.keyMap[pk] = peer
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device.peers.empty.Set(false)
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// start peer
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if peer.device.isUp.Get() {
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peer.Start()
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}
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return peer, nil
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}
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func (peer *Peer) SendBuffer(buffer []byte) error {
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peer.device.net.RLock()
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defer peer.device.net.RUnlock()
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if peer.device.net.bind == nil {
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// Packets can leak through to SendBuffer while the device is closing.
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// When that happens, drop them silently to avoid spurious errors.
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if peer.device.isClosed.Get() {
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return nil
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}
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return errors.New("no bind")
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}
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peer.RLock()
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defer peer.RUnlock()
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if peer.endpoint == nil {
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return errors.New("no known endpoint for peer")
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}
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err := peer.device.net.bind.Send(buffer, peer.endpoint)
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if err == nil {
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atomic.AddUint64(&peer.stats.txBytes, uint64(len(buffer)))
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}
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return err
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}
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func (peer *Peer) String() string {
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base64Key := base64.StdEncoding.EncodeToString(peer.handshake.remoteStatic[:])
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abbreviatedKey := "invalid"
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if len(base64Key) == 44 {
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abbreviatedKey = base64Key[0:4] + "…" + base64Key[39:43]
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}
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return fmt.Sprintf("peer(%s)", abbreviatedKey)
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}
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func (peer *Peer) Start() {
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// should never start a peer on a closed device
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if peer.device.isClosed.Get() {
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return
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}
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// prevent simultaneous start/stop operations
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peer.routines.Lock()
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defer peer.routines.Unlock()
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if peer.isRunning.Get() {
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return
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}
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device := peer.device
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device.log.Debug.Println(peer, "- Starting...")
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// reset routine state
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peer.routines.stopping.Wait()
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peer.routines.stop = make(chan struct{})
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peer.routines.stopping.Add(PeerRoutineNumber)
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// prepare queues
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peer.queue.Lock()
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peer.queue.nonce = make(chan *QueueOutboundElement, QueueOutboundSize)
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peer.queue.outbound = make(chan *QueueOutboundElement, QueueOutboundSize)
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peer.queue.inbound = make(chan *QueueInboundElement, QueueInboundSize)
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peer.queue.Unlock()
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peer.timersInit()
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peer.handshake.lastSentHandshake = time.Now().Add(-(RekeyTimeout + time.Second))
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peer.signals.newKeypairArrived = make(chan struct{}, 1)
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peer.signals.flushNonceQueue = make(chan struct{}, 1)
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// wait for routines to start
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// RoutineNonce writes to the encryption queue; keep it alive until we are done.
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device.queue.encryption.wg.Add(1)
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go peer.RoutineNonce()
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go peer.RoutineSequentialSender()
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go peer.RoutineSequentialReceiver()
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peer.isRunning.Set(true)
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}
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func (peer *Peer) ZeroAndFlushAll() {
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device := peer.device
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// clear key pairs
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keypairs := &peer.keypairs
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keypairs.Lock()
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device.DeleteKeypair(keypairs.previous)
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device.DeleteKeypair(keypairs.current)
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device.DeleteKeypair(keypairs.loadNext())
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keypairs.previous = nil
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keypairs.current = nil
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keypairs.storeNext(nil)
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keypairs.Unlock()
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// clear handshake state
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handshake := &peer.handshake
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handshake.mutex.Lock()
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device.indexTable.Delete(handshake.localIndex)
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handshake.Clear()
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handshake.mutex.Unlock()
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peer.FlushNonceQueue()
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}
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func (peer *Peer) ExpireCurrentKeypairs() {
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handshake := &peer.handshake
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handshake.mutex.Lock()
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peer.device.indexTable.Delete(handshake.localIndex)
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handshake.Clear()
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peer.handshake.lastSentHandshake = time.Now().Add(-(RekeyTimeout + time.Second))
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handshake.mutex.Unlock()
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keypairs := &peer.keypairs
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keypairs.Lock()
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if keypairs.current != nil {
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atomic.StoreUint64(&keypairs.current.sendNonce, RejectAfterMessages)
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}
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if keypairs.next != nil {
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next := keypairs.loadNext()
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atomic.StoreUint64(&next.sendNonce, RejectAfterMessages)
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}
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keypairs.Unlock()
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}
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func (peer *Peer) Stop() {
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// prevent simultaneous start/stop operations
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if !peer.isRunning.Swap(false) {
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return
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}
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peer.routines.Lock()
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defer peer.routines.Unlock()
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peer.device.log.Debug.Println(peer, "- Stopping...")
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peer.timersStop()
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// stop & wait for ongoing peer routines
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close(peer.routines.stop)
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peer.routines.stopping.Wait()
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// close queues
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peer.queue.Lock()
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close(peer.queue.nonce)
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close(peer.queue.inbound)
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peer.queue.Unlock()
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peer.ZeroAndFlushAll()
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}
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func (peer *Peer) SetEndpointFromPacket(endpoint conn.Endpoint) {
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if peer.disableRoaming {
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return
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}
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peer.Lock()
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peer.endpoint = endpoint
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peer.Unlock()
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}
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