Add reconfig listener

ipn/ipnlocal/local.go

@@ -370,10 +370,6 @@ type LocalBackend struct {
 	// backend is healthy and captive portal detection is not required
 	// (sending false).
 	needsCaptiveDetection chan bool
-
-	cfg  *wgcfg.Config
-	rcfg *router.Config
-	dcfg *dns.Config
 }
 
 // HealthTracker returns the health tracker for the backend.
@@ -4264,10 +4260,6 @@ func (b *LocalBackend) authReconfig() {
 	}
 
 	b.initPeerAPIListener()
-
-	b.cfg = cfg
-	b.rcfg = rcfg
-	b.dcfg = dcfg
 }
 
 // shouldUseOneCGNATRoute reports whether we should prefer to make one big

ipn/ipnlocal/local_export.go

@@ -3,16 +3,14 @@ package ipnlocal
 import (
 	"sync/atomic"
 
-	"github.com/sagernet/tailscale/net/dns"
+	"github.com/sagernet/tailscale/wgengine"
 	"github.com/sagernet/tailscale/wgengine/filter"
-	"github.com/sagernet/tailscale/wgengine/router"
-	"github.com/sagernet/tailscale/wgengine/wgcfg"
 )
 
 func (b *LocalBackend) ExportFilter() *atomic.Pointer[filter.Filter] {
 	return &b.filterAtomic
 }
 
-func (b *LocalBackend) ExportConfig() (*wgcfg.Config, *dns.Config, *router.Config) {
-	return b.cfg, b.dcfg, b.rcfg
+func (b *LocalBackend) ExportEngine() wgengine.Engine {
+	return b.e
 }

wgengine/userspace.go

@@ -90,8 +90,10 @@ const statusPollInterval = 1 * time.Minute
 const networkLoggerUploadTimeout = 5 * time.Second
 
 type userspaceEngine struct {
-	ctx              context.Context
-	workers          int
+	ctx        context.Context
+	workers    int
+	onReconfig ReconfigListener
+
 	logf             logger.Logf
 	wgLogger         *wglog.Logger //a wireguard-go logging wrapper
 	reqCh            chan struct{}
@@ -1051,6 +1053,10 @@ func (e *userspaceEngine) Reconfig(cfg *wgcfg.Config, routerCfg *router.Config,
 		}
 	}
 
+	if routerChanged && e.onReconfig != nil {
+		e.onReconfig(cfg, routerCfg, dnsCfg)
+	}
+
 	e.logf("[v1] wgengine: Reconfig done")
 	return nil
 }

wgengine/userspace_export.go

@@ -0,0 +1,19 @@
+package wgengine
+
+import (
+	"github.com/sagernet/tailscale/net/dns"
+	"github.com/sagernet/tailscale/wgengine/router"
+	"github.com/sagernet/tailscale/wgengine/wgcfg"
+)
+
+type ExportedUserspaceEngine interface {
+	SetOnReconfigListener(listener ReconfigListener)
+}
+
+type ReconfigListener = func(cfg *wgcfg.Config, routerCfg *router.Config, dnsCfg *dns.Config)
+
+func (e *userspaceEngine) SetOnReconfigListener(listener ReconfigListener) {
+	e.mu.Lock()
+	defer e.mu.Unlock()
+	e.onReconfig = listener
+}