wireguard-go/peer.go

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/* SPDX-License-Identifier: GPL-2.0
*
* Copyright (C) 2017-2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
*/
package main
import (
"encoding/base64"
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"errors"
"fmt"
"sync"
"time"
)
const (
PeerRoutineNumber = 3
)
type Peer struct {
isRunning AtomicBool
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mutex 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
device *Device
endpoint Endpoint
persistentKeepaliveInterval uint16
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// This must be 64-bit aligned, so make sure the above members come out to even alignment and pad accordingly
stats struct {
txBytes uint64 // bytes send to peer (endpoint)
rxBytes uint64 // bytes received from peer
lastHandshakeNano int64 // nano seconds since epoch
}
timers struct {
retransmitHandshake *Timer
sendKeepalive *Timer
newHandshake *Timer
zeroKeyMaterial *Timer
persistentKeepalive *Timer
handshakeAttempts uint
needAnotherKeepalive bool
sentLastMinuteHandshake bool
}
signals struct {
newKeypairArrived chan struct{}
flushNonceQueue chan struct{}
}
queue struct {
nonce chan *QueueOutboundElement // nonce / pre-handshake queue
outbound chan *QueueOutboundElement // sequential ordering of work
inbound chan *QueueInboundElement // sequential ordering of work
packetInNonceQueueIsAwaitingKey bool
}
routines struct {
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mutex sync.Mutex // held when stopping / starting routines
starting sync.WaitGroup // routines pending start
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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cookieGenerator CookieGenerator
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}
func (device *Device) NewPeer(pk NoisePublicKey) (*Peer, error) {
if device.isClosed.Get() {
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return nil, errors.New("device closed")
}
// lock resources
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device.staticIdentity.mutex.RLock()
defer device.staticIdentity.mutex.RUnlock()
device.peers.mutex.Lock()
defer device.peers.mutex.Unlock()
// check if over limit
if len(device.peers.keyMap) >= MaxPeers {
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return nil, errors.New("too many peers")
}
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// create peer
peer := new(Peer)
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peer.mutex.Lock()
defer peer.mutex.Unlock()
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peer.cookieGenerator.Init(pk)
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peer.device = device
peer.isRunning.Set(false)
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// map public key
_, 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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}
device.peers.keyMap[pk] = peer
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// pre-compute DH
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handshake := &peer.handshake
handshake.mutex.Lock()
handshake.remoteStatic = pk
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handshake.precomputedStaticStatic = device.staticIdentity.privateKey.sharedSecret(pk)
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handshake.mutex.Unlock()
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// reset endpoint
peer.endpoint = nil
// 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()
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if peer.device.net.bind == nil {
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return errors.New("no bind")
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}
peer.mutex.RLock()
defer peer.mutex.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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return peer.device.net.bind.Send(buffer, peer.endpoint)
}
func (peer *Peer) String() string {
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base64Key := base64.StdEncoding.EncodeToString(peer.handshake.remoteStatic[:])
abbreviatedKey := "invalid"
if len(base64Key) == 44 {
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abbreviatedKey = base64Key[0:4] + "…" + base64Key[39:43]
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}
return fmt.Sprintf("peer(%s)", abbreviatedKey)
}
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()
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if peer.isRunning.Get() {
return
}
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device := peer.device
device.log.Debug.Println(peer, ": Starting...")
// reset routine state
peer.routines.starting.Wait()
peer.routines.stopping.Wait()
peer.routines.stop = make(chan struct{})
peer.routines.starting.Add(PeerRoutineNumber)
peer.routines.stopping.Add(PeerRoutineNumber)
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// prepare queues
peer.queue.nonce = make(chan *QueueOutboundElement, QueueOutboundSize)
peer.queue.outbound = make(chan *QueueOutboundElement, QueueOutboundSize)
peer.queue.inbound = make(chan *QueueInboundElement, QueueInboundSize)
peer.timersInit()
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peer.handshake.lastSentHandshake = time.Now().Add(-(RekeyTimeout + time.Second))
peer.signals.newKeypairArrived = make(chan struct{}, 1)
peer.signals.flushNonceQueue = make(chan struct{}, 1)
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// wait for routines to start
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go peer.RoutineNonce()
go peer.RoutineSequentialSender()
go peer.RoutineSequentialReceiver()
peer.routines.starting.Wait()
peer.isRunning.Set(true)
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}
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func (peer *Peer) ZeroAndFlushAll() {
device := peer.device
// clear key pairs
keypairs := &peer.keypairs
keypairs.mutex.Lock()
device.DeleteKeypair(keypairs.previous)
device.DeleteKeypair(keypairs.current)
device.DeleteKeypair(keypairs.next)
keypairs.previous = nil
keypairs.current = nil
keypairs.next = nil
keypairs.mutex.Unlock()
// clear handshake state
handshake := &peer.handshake
handshake.mutex.Lock()
device.indexTable.Delete(handshake.localIndex)
handshake.Clear()
handshake.mutex.Unlock()
peer.FlushNonceQueue()
}
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func (peer *Peer) Stop() {
// prevent simultaneous start/stop operations
peer.routines.mutex.Lock()
defer peer.routines.mutex.Unlock()
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if !peer.isRunning.Swap(false) {
return
}
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peer.device.log.Debug.Println(peer, ": Stopping...")
peer.timersStop()
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// stop & wait for ongoing peer routines
peer.routines.starting.Wait()
close(peer.routines.stop)
peer.routines.stopping.Wait()
// close queues
close(peer.queue.nonce)
close(peer.queue.outbound)
close(peer.queue.inbound)
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peer.ZeroAndFlushAll()
}