device: fix persistent_keepalive_interval data races

Co-authored-by: David Anderson <danderson@tailscale.com>
Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
This commit is contained in:
Josh Bleecher Snyder 2020-12-14 15:28:52 -08:00 committed by Jason A. Donenfeld
parent e1fa1cc556
commit 63066ce406
5 changed files with 22 additions and 9 deletions

View File

@ -163,7 +163,7 @@ func deviceUpdateState(device *Device) {
device.peers.RLock()
for _, peer := range device.peers.keyMap {
peer.Start()
if peer.persistentKeepaliveInterval > 0 {
if atomic.LoadUint32(&peer.persistentKeepaliveInterval) > 0 {
peer.SendKeepalive()
}
}

View File

@ -215,7 +215,20 @@ func TestConcurrencySafety(t *testing.T) {
}()
warmup.Wait()
// coming soon: more things here...
// Change persistent_keepalive_interval concurrently with tunnel use.
t.Run("persistentKeepaliveInterval", func(t *testing.T) {
cfg := uapiCfg(
"public_key", "f70dbb6b1b92a1dde1c783b297016af3f572fef13b0abb16a2623d89a58e9725",
"persistent_keepalive_interval", "1",
)
for i := 0; i < 1000; i++ {
cfg.Seek(0, io.SeekStart)
err := pair[0].dev.IpcSetOperation(cfg)
if err != nil {
t.Fatal(err)
}
}
})
close(done)
}

View File

@ -27,7 +27,7 @@ type Peer struct {
handshake Handshake
device *Device
endpoint conn.Endpoint
persistentKeepaliveInterval uint16
persistentKeepaliveInterval uint32 // accessed atomically
disableRoaming bool
// These fields are accessed with atomic operations, which must be

View File

@ -138,7 +138,7 @@ func expiredZeroKeyMaterial(peer *Peer) {
}
func expiredPersistentKeepalive(peer *Peer) {
if peer.persistentKeepaliveInterval > 0 {
if atomic.LoadUint32(&peer.persistentKeepaliveInterval) > 0 {
peer.SendKeepalive()
}
}
@ -201,8 +201,9 @@ func (peer *Peer) timersSessionDerived() {
/* Should be called before a packet with authentication -- keepalive, data, or handshake -- is sent, or after one is received. */
func (peer *Peer) timersAnyAuthenticatedPacketTraversal() {
if peer.persistentKeepaliveInterval > 0 && peer.timersActive() {
peer.timers.persistentKeepalive.Mod(time.Duration(peer.persistentKeepaliveInterval) * time.Second)
keepalive := atomic.LoadUint32(&peer.persistentKeepaliveInterval)
if keepalive > 0 && peer.timersActive() {
peer.timers.persistentKeepalive.Mod(time.Duration(keepalive) * time.Second)
}
}

View File

@ -86,7 +86,7 @@ func (device *Device) IpcGetOperation(socket *bufio.Writer) error {
send(fmt.Sprintf("last_handshake_time_nsec=%d", nano))
send(fmt.Sprintf("tx_bytes=%d", atomic.LoadUint64(&peer.stats.txBytes)))
send(fmt.Sprintf("rx_bytes=%d", atomic.LoadUint64(&peer.stats.rxBytes)))
send(fmt.Sprintf("persistent_keepalive_interval=%d", peer.persistentKeepaliveInterval))
send(fmt.Sprintf("persistent_keepalive_interval=%d", atomic.LoadUint32(&peer.persistentKeepaliveInterval)))
for _, ip := range device.allowedips.EntriesForPeer(peer) {
send("allowed_ip=" + ip.String())
@ -333,8 +333,7 @@ func (device *Device) IpcSetOperation(r io.Reader) error {
return &IPCError{ipc.IpcErrorInvalid}
}
old := peer.persistentKeepaliveInterval
peer.persistentKeepaliveInterval = uint16(secs)
old := atomic.SwapUint32(&peer.persistentKeepaliveInterval, uint32(secs))
// send immediate keepalive if we're turning it on and before it wasn't on