wgengine: separately dedupe wireguard configs and router configs.

Otherwise iOS/macOS will reconfigure their routing every time anything
minor changes in the netmap (in particular, endpoints and DERP homes),
which is way too often.

Some users reported "network reconfigured" errors from Chrome when this
happens.

Signed-off-by: Avery Pennarun <apenwarr@tailscale.com>
This commit is contained in:
Avery Pennarun 2020-05-31 02:37:58 -04:00
parent f0b6ba78e8
commit e46238a2af

View File

@ -58,7 +58,8 @@ type userspaceEngine struct {
linkMon *monitor.Mon
wgLock sync.Mutex // serializes all wgdev operations; see lock order comment below
lastReconfig string
lastEngineSig string
lastRouterSig string
lastCfg wgcfg.Config
mu sync.Mutex // guards following; see lock order comment below
@ -359,17 +360,18 @@ func (e *userspaceEngine) pinger(peerKey wgcfg.Key, ips []wgcfg.IP) {
p.run(ctx, peerKey, ips, srcIP)
}
func configSignature(cfg *wgcfg.Config, routerCfg *router.Config) (string, error) {
func configSignatures(cfg *wgcfg.Config, routerCfg *router.Config) (string, string, error) {
// TODO(apenwarr): get rid of uapi stuff for in-process comms
uapi, err := cfg.ToUAPI()
if err != nil {
return "", err
return "", "", err
}
return fmt.Sprintf("%s %v", uapi, routerCfg), nil
return uapi, fmt.Sprintf("%v", routerCfg), nil
}
func (e *userspaceEngine) Reconfig(cfg *wgcfg.Config, routerCfg *router.Config) error {
e.logf("Reconfig: router.Set: %p %p", cfg, routerCfg)
if routerCfg == nil {
panic("routerCfg must not be nil")
}
@ -386,18 +388,22 @@ func (e *userspaceEngine) Reconfig(cfg *wgcfg.Config, routerCfg *router.Config)
}
e.mu.Unlock()
rc, err := configSignature(cfg, routerCfg)
ec, rc, err := configSignatures(cfg, routerCfg)
if err != nil {
return err
}
if rc == e.lastReconfig {
engineChanged := ec != e.lastEngineSig
routerChanged := rc != e.lastRouterSig
if !engineChanged && !routerChanged {
return ErrNoChanges
}
e.logf("wgengine: Reconfig: configuring userspace wireguard engine")
e.lastReconfig = rc
e.lastEngineSig = ec
e.lastRouterSig = rc
e.lastCfg = cfg.Copy()
e.logf("wgengine: Reconfig: configuring userspace wireguard engine")
if engineChanged {
// Tell magicsock about the new (or initial) private key
// (which is needed by DERP) before wgdev gets it, as wgdev
// will start trying to handshake, which we want to be able to
@ -412,10 +418,13 @@ func (e *userspaceEngine) Reconfig(cfg *wgcfg.Config, routerCfg *router.Config)
}
e.magicConn.UpdatePeers(peerSet)
}
if routerChanged {
if err := e.router.Set(routerCfg); err != nil {
return err
}
}
e.logf("wgengine: Reconfig done")
return nil