control, ipn, tailcfg: enable seamless key renewal by default

Previously, seamless key renewal was an opt-in feature.  Customers had
to set a `seamless-key-renewal` node attribute in their policy file.

This patch enables seamless key renewal by default for all clients.

It includes a `disable-seamless-key-renewal` node attribute we can set
in Control, so we can manage the rollout and disable the feature for
clients with known bugs.  This new attribute makes the feature opt-out.

Updates tailscale/corp#31479

Signed-off-by: Alex Chan <alexc@tailscale.com>
This commit is contained in:
Alex Chan 2025-09-11 13:11:41 +01:00 committed by Alex Chan
parent 1c9aaa444d
commit cd153aa644
3 changed files with 38 additions and 10 deletions

View File

@ -62,8 +62,9 @@ type Knobs struct {
// netfiltering, unless overridden by the user.
LinuxForceNfTables atomic.Bool
// SeamlessKeyRenewal is whether to enable the alpha functionality of
// renewing node keys without breaking connections.
// SeamlessKeyRenewal is whether to renew node keys without breaking connections.
// This is enabled by default in 1.90 and later, but we but we can remotely disable
// it from the control plane if there's a problem.
// http://go/seamless-key-renewal
SeamlessKeyRenewal atomic.Bool
@ -128,6 +129,7 @@ func (k *Knobs) UpdateFromNodeAttributes(capMap tailcfg.NodeCapMap) {
forceIPTables = has(tailcfg.NodeAttrLinuxMustUseIPTables)
forceNfTables = has(tailcfg.NodeAttrLinuxMustUseNfTables)
seamlessKeyRenewal = has(tailcfg.NodeAttrSeamlessKeyRenewal)
disableSeamlessKeyRenewal = has(tailcfg.NodeAttrDisableSeamlessKeyRenewal)
probeUDPLifetime = has(tailcfg.NodeAttrProbeUDPLifetime)
appCStoreRoutes = has(tailcfg.NodeAttrStoreAppCRoutes)
userDialUseRoutes = has(tailcfg.NodeAttrUserDialUseRoutes)
@ -154,7 +156,6 @@ func (k *Knobs) UpdateFromNodeAttributes(capMap tailcfg.NodeCapMap) {
k.SilentDisco.Store(silentDisco)
k.LinuxForceIPTables.Store(forceIPTables)
k.LinuxForceNfTables.Store(forceNfTables)
k.SeamlessKeyRenewal.Store(seamlessKeyRenewal)
k.ProbeUDPLifetime.Store(probeUDPLifetime)
k.AppCStoreRoutes.Store(appCStoreRoutes)
k.UserDialUseRoutes.Store(userDialUseRoutes)
@ -162,6 +163,21 @@ func (k *Knobs) UpdateFromNodeAttributes(capMap tailcfg.NodeCapMap) {
k.DisableLocalDNSOverrideViaNRPT.Store(disableLocalDNSOverrideViaNRPT)
k.DisableCaptivePortalDetection.Store(disableCaptivePortalDetection)
k.DisableSkipStatusQueue.Store(disableSkipStatusQueue)
// If both attributes are present, then "enable" should win. This reflects
// the history of seamless key renewal.
//
// Before 1.90, seamless was a private alpha, opt-in feature. Devices would
// only seamless do if customers opted in using the seamless renewal attr.
//
// In 1.90 and later, seamless is the default behaviour, and devices will use
// seamless unless explicitly told not to by control (e.g. if we discover
// a bug and want clients to use the prior behaviour).
//
// If a customer has opted in to the pre-1.90 seamless implementation, we
// don't want to switch it off for them -- we only want to switch it off for
// devices that haven't opted in.
k.SeamlessKeyRenewal.Store(seamlessKeyRenewal || !disableSeamlessKeyRenewal)
}
// AsDebugJSON returns k as something that can be marshalled with json.Marshal

View File

@ -7420,10 +7420,10 @@ func (b *LocalBackend) readRouteInfoLocked() (*appc.RouteInfo, error) {
return ri, nil
}
// seamlessRenewalEnabled reports whether seamless key renewals are enabled
// (i.e. we saw our self node with the SeamlessKeyRenewal attr in a netmap).
// This enables beta functionality of renewing node keys without breaking
// connections.
// seamlessRenewalEnabled reports whether seamless key renewals are enabled.
//
// As of 2025-09-11, this is the default behaviour unless nodes receive
// [tailcfg.NodeAttrDisableSeamlessKeyRenewal] in their netmap.
func (b *LocalBackend) seamlessRenewalEnabled() bool {
return b.ControlKnobs().SeamlessKeyRenewal.Load()
}

View File

@ -170,7 +170,8 @@ type CapabilityVersion int
// - 123: 2025-07-28: fix deadlock regression from cryptokey routing change (issue #16651)
// - 124: 2025-08-08: removed NodeAttrDisableMagicSockCryptoRouting support, crypto routing is now mandatory
// - 125: 2025-08-11: dnstype.Resolver adds UseWithExitNode field.
const CurrentCapabilityVersion CapabilityVersion = 125
// - 126: 2025-09-17: Client uses seamless key renewal unless disabled by control (tailscale/corp#31479)
const CurrentCapabilityVersion CapabilityVersion = 126
// ID is an integer ID for a user, node, or login allocated by the
// control plane.
@ -2530,8 +2531,19 @@ const (
// This cannot be set simultaneously with NodeAttrLinuxMustUseIPTables.
NodeAttrLinuxMustUseNfTables NodeCapability = "linux-netfilter?v=nftables"
// NodeAttrSeamlessKeyRenewal makes clients enable beta functionality
// of renewing node keys without breaking connections.
// NodeAttrDisableSeamlessKeyRenewal disables seamless key renewal, which is
// enabled by default in clients as of 2025-09-17 (1.90 and later).
//
// We will use this attribute to manage the rollout, and disable seamless in
// clients with known bugs.
// http://go/seamless-key-renewal
NodeAttrDisableSeamlessKeyRenewal NodeCapability = "disable-seamless-key-renewal"
// NodeAttrSeamlessKeyRenewal was used to opt-in to seamless key renewal
// during its private alpha.
//
// Deprecated: NodeAttrSeamlessKeyRenewal is deprecated as of CapabilityVersion 126,
// because seamless key renewal is now enabled by default.
NodeAttrSeamlessKeyRenewal NodeCapability = "seamless-key-renewal"
// NodeAttrProbeUDPLifetime makes the client probe UDP path lifetime at the