[client] Sweep network-bound connections when the OS switches networks

On a network switch (e.g. cellular to WiFi) the management, signal and
relay sockets stay bound to the old network and look alive until the OS
tears them down — measured at 5 seconds of dead air on Android, while
the UI kept claiming Connected. The Android client papered over this
with a full engine restart, paying for it with a torn-down TUN device
and discarded peer state.

Introduce client/netsweep: connections register on dial and deregister
on close, and a sweep closes everything registered while aborting
in-flight dials through sweep-cancellable dial contexts. The aborted
dials matter: a relay dial started on the dying network would otherwise
hold the reconnect loop hostage for the QUIC handshake timeout. After a
sweep every failure surfaces as an ordinary read/write error and the
existing retry loops redial immediately on the new network.

The sweeper reaches the three long-lived connections through the same
options that carry the netstate gate: a gRPC dial option wraps the
management and signal transports (reconnects included), and the relay
client wraps its connection in one place for the picker, the guard and
foreign relays alike. Everything is nil-safe; platforms that inject no
sweeper are untouched.

Mobile clients expose the sweep as NotifyNetworkChange. Measured on
Android against the engine restart it replaces: recovery in 1.6s
instead of 3.2s, no Disconnected flash, and the TUN device, WireGuard
config and peer state survive.
This commit is contained in:
Zoltan Papp
2026-08-11 00:58:50 +02:00
parent 8fb3e707af
commit 072fa8143b
10 changed files with 168 additions and 54 deletions

View File

@@ -26,6 +26,7 @@ import (
"github.com/netbirdio/netbird/client/internal/stdnet"
"github.com/netbirdio/netbird/client/net"
"github.com/netbirdio/netbird/client/netstate"
"github.com/netbirdio/netbird/client/netsweep"
"github.com/netbirdio/netbird/client/system"
"github.com/netbirdio/netbird/formatter"
"github.com/netbirdio/netbird/route"
@@ -78,6 +79,9 @@ type Client struct {
// ConnectClient, which distributes it to every reconnection loop.
netState *netstate.State
// sweeper also outlives engine restarts; NotifyNetworkChange sweeps it.
sweeper *netsweep.Sweeper
stateMu sync.RWMutex
connectClient *internal.ConnectClient
config *profilemanager.Config
@@ -149,6 +153,7 @@ func NewClient(androidSDKVersion int, deviceName string, uiVersion string, tunAd
ctxCancelLock: &sync.Mutex{},
networkChangeListener: networkChangeListener,
netState: netstate.New(),
sweeper: netsweep.New(),
}
}
@@ -161,6 +166,14 @@ func (c *Client) SetNetworkAvailable(available bool) {
c.recorder.SetNetworkAvailable(available)
}
// NotifyNetworkChange cuts the management, signal and relay connections
// after the OS switched networks, so the reconnect loops redial immediately
// on the new one. The engine and the TUN device stay untouched.
func (c *Client) NotifyNetworkChange() {
n := c.sweeper.Sweep()
log.Infof("network change: swept %d connections", n)
}
// Run start the internal client. It is a blocker function
func (c *Client) Run(platformFiles PlatformFiles, urlOpener URLOpener, isAndroidTV bool, dns *DNSList, dnsReadyListener DnsReadyListener, envList *EnvList) error {
exportEnvList(envList)
@@ -198,7 +211,8 @@ func (c *Client) Run(platformFiles PlatformFiles, urlOpener URLOpener, isAndroid
}
// todo do not throw error in case of cancelled context
ctx = internal.CtxInitState(ctx)
connectClient := internal.NewConnectClient(ctx, cfg, c.recorder, internal.WithNetworkState(c.netState))
connectClient := internal.NewConnectClient(ctx, cfg, c.recorder,
internal.WithNetworkState(c.netState), internal.WithSweeper(c.sweeper))
c.setState(cfg, cacheDir, cfgFile, connectClient)
// This path runs the interactive SSO flow, so reaching here means the peer
// is authenticated again — release the latch Status() reports from. Clear
@@ -239,7 +253,8 @@ func (c *Client) RunWithoutLogin(platformFiles PlatformFiles, dns *DNSList, dnsR
// todo do not throw error in case of cancelled context
ctx = internal.CtxInitState(ctx)
connectClient := internal.NewConnectClient(ctx, cfg, c.recorder, internal.WithNetworkState(c.netState))
connectClient := internal.NewConnectClient(ctx, cfg, c.recorder,
internal.WithNetworkState(c.netState), internal.WithSweeper(c.sweeper))
c.setState(cfg, cacheDir, cfgFile, connectClient)
return connectClient.RunOnAndroid(c.tunAdapter, c.iFaceDiscover, c.networkChangeListener, slices.Clone(dns.items), dnsReadyListener, stateFile, cacheDir)
}