Update dependencies

vendor/tailscale.com/wgengine/router/callback.go

@@ -0,0 +1,91 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+package router
+
+import (
+	"sync"
+
+	"tailscale.com/net/dns"
+)
+
+// CallbackRouter is an implementation of both Router and dns.OSConfigurator.
+// When either network or DNS settings are changed, SetBoth is called with both configs.
+// Mainly used as a shim for OSes that want to set both network and
+// DNS configuration simultaneously (Mac, iOS, Android).
+type CallbackRouter struct {
+	SetBoth  func(rcfg *Config, dcfg *dns.OSConfig) error
+	SplitDNS bool
+
+	// GetBaseConfigFunc optionally specifies a function to return the current DNS
+	// config in response to GetBaseConfig.
+	//
+	// If nil, reading the current config isn't supported and GetBaseConfig()
+	// will return ErrGetBaseConfigNotSupported.
+	GetBaseConfigFunc func() (dns.OSConfig, error)
+
+	// InitialMTU is the MTU the tun should be initialized with.
+	// Zero means don't change the MTU from the default. This MTU
+	// is applied only once, shortly after the TUN is created, and
+	// ignored thereafter.
+	InitialMTU uint32
+
+	mu        sync.Mutex    // protects all the following
+	didSetMTU bool          // if we set the MTU already
+	rcfg      *Config       // last applied router config
+	dcfg      *dns.OSConfig // last applied DNS config
+}
+
+// Up implements Router.
+func (r *CallbackRouter) Up() error {
+	return nil // TODO: check that all callers have no need for initialization
+}
+
+// Set implements Router.
+func (r *CallbackRouter) Set(rcfg *Config) error {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	if r.rcfg.Equal(rcfg) {
+		return nil
+	}
+	if r.didSetMTU == false {
+		r.didSetMTU = true
+		rcfg.NewMTU = int(r.InitialMTU)
+	}
+	r.rcfg = rcfg
+	return r.SetBoth(r.rcfg, r.dcfg)
+}
+
+// UpdateMagicsockPort implements the Router interface. This implementation
+// does nothing and returns nil because this router does not currently need
+// to know what the magicsock UDP port is.
+func (r *CallbackRouter) UpdateMagicsockPort(_ uint16, _ string) error {
+	return nil
+}
+
+// SetDNS implements dns.OSConfigurator.
+func (r *CallbackRouter) SetDNS(dcfg dns.OSConfig) error {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	if r.dcfg != nil && r.dcfg.Equal(dcfg) {
+		return nil
+	}
+	r.dcfg = &dcfg
+	return r.SetBoth(r.rcfg, r.dcfg)
+}
+
+// SupportsSplitDNS implements dns.OSConfigurator.
+func (r *CallbackRouter) SupportsSplitDNS() bool {
+	return r.SplitDNS
+}
+
+func (r *CallbackRouter) GetBaseConfig() (dns.OSConfig, error) {
+	if r.GetBaseConfigFunc == nil {
+		return dns.OSConfig{}, dns.ErrGetBaseConfigNotSupported
+	}
+	return r.GetBaseConfigFunc()
+}
+
+func (r *CallbackRouter) Close() error {
+	return r.SetBoth(nil, nil) // TODO: check if makes sense
+}