tailscale/wgengine/router/callback.go
Naman Sood 97f84200ac
wgengine/router: implement UpdateMagicsockPort for CallbackRouter (#10494)
Updates #9084.

Signed-off-by: Naman Sood <mail@nsood.in>
2023-12-07 10:45:14 -05:00

92 lines
2.6 KiB
Go

// 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
}