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tailscale/wgengine/userspace.go

1531 lines
45 KiB
Go

// Copyright (c) Tailscale Inc & AUTHORS
// SPDX-License-Identifier: BSD-3-Clause
package wgengine
import (
"bufio"
"context"
crand "crypto/rand"
"errors"
"fmt"
"io"
"math"
"net/netip"
"runtime"
"slices"
"strings"
"sync"
"time"
"github.com/tailscale/wireguard-go/device"
"github.com/tailscale/wireguard-go/tun"
"tailscale.com/control/controlknobs"
"tailscale.com/envknob"
"tailscale.com/health"
"tailscale.com/ipn/ipnstate"
"tailscale.com/net/dns"
"tailscale.com/net/flowtrack"
"tailscale.com/net/netmon"
"tailscale.com/net/packet"
"tailscale.com/net/sockstats"
"tailscale.com/net/tsaddr"
"tailscale.com/net/tsdial"
"tailscale.com/net/tshttpproxy"
"tailscale.com/net/tstun"
"tailscale.com/syncs"
"tailscale.com/tailcfg"
"tailscale.com/tailfs"
"tailscale.com/tstime/mono"
"tailscale.com/types/dnstype"
"tailscale.com/types/ipproto"
"tailscale.com/types/key"
"tailscale.com/types/logger"
"tailscale.com/types/netmap"
"tailscale.com/types/views"
"tailscale.com/util/clientmetric"
"tailscale.com/util/deephash"
"tailscale.com/util/mak"
"tailscale.com/util/set"
"tailscale.com/wgengine/capture"
"tailscale.com/wgengine/filter"
"tailscale.com/wgengine/magicsock"
"tailscale.com/wgengine/netlog"
"tailscale.com/wgengine/router"
"tailscale.com/wgengine/wgcfg"
"tailscale.com/wgengine/wgint"
"tailscale.com/wgengine/wglog"
)
// Lazy wireguard-go configuration parameters.
const (
// lazyPeerIdleThreshold is the idle duration after
// which we remove a peer from the wireguard configuration.
// (This includes peers that have never been idle, which
// effectively have infinite idleness)
lazyPeerIdleThreshold = 5 * time.Minute
// packetSendTimeUpdateFrequency controls how often we record
// the time that we wrote a packet to an IP address.
packetSendTimeUpdateFrequency = 10 * time.Second
// packetSendRecheckWireguardThreshold controls how long we can go
// between packet sends to an IP before checking to see
// whether this IP address needs to be added back to the
// WireGuard peer oconfig.
packetSendRecheckWireguardThreshold = 1 * time.Minute
)
// statusPollInterval is how often we ask wireguard-go for its engine
// status (as long as there's activity). See docs on its use below.
const statusPollInterval = 1 * time.Minute
// networkLoggerUploadTimeout is the maximum timeout to wait when
// shutting down the network logger as it uploads the last network log messages.
const networkLoggerUploadTimeout = 5 * time.Second
type userspaceEngine struct {
logf logger.Logf
wgLogger *wglog.Logger //a wireguard-go logging wrapper
reqCh chan struct{}
waitCh chan struct{} // chan is closed when first Close call completes; contrast with closing bool
timeNow func() mono.Time
tundev *tstun.Wrapper
wgdev *device.Device
router router.Router
confListenPort uint16 // original conf.ListenPort
dns *dns.Manager
magicConn *magicsock.Conn
netMon *netmon.Monitor
netMonOwned bool // whether we created netMon (and thus need to close it)
netMonUnregister func() // unsubscribes from changes; used regardless of netMonOwned
birdClient BIRDClient // or nil
controlKnobs *controlknobs.Knobs // or nil
testMaybeReconfigHook func() // for tests; if non-nil, fires if maybeReconfigWireguardLocked called
// isLocalAddr reports the whether an IP is assigned to the local
// tunnel interface. It's used to reflect local packets
// incorrectly sent to us.
isLocalAddr syncs.AtomicValue[func(netip.Addr) bool]
// isDNSIPOverTailscale reports the whether a DNS resolver's IP
// is being routed over Tailscale.
isDNSIPOverTailscale syncs.AtomicValue[func(netip.Addr) bool]
wgLock sync.Mutex // serializes all wgdev operations; see lock order comment below
lastCfgFull wgcfg.Config
lastNMinPeers int
lastRouterSig deephash.Sum // of router.Config
lastEngineSigFull deephash.Sum // of full wireguard config
lastEngineSigTrim deephash.Sum // of trimmed wireguard config
lastDNSConfig *dns.Config
lastIsSubnetRouter bool // was the node a primary subnet router in the last run.
recvActivityAt map[key.NodePublic]mono.Time
trimmedNodes map[key.NodePublic]bool // set of node keys of peers currently excluded from wireguard config
sentActivityAt map[netip.Addr]*mono.Time // value is accessed atomically
destIPActivityFuncs map[netip.Addr]func()
lastStatusPollTime mono.Time // last time we polled the engine status
mu sync.Mutex // guards following; see lock order comment below
netMap *netmap.NetworkMap // or nil
closing bool // Close was called (even if we're still closing)
statusCallback StatusCallback
peerSequence []key.NodePublic
endpoints []tailcfg.Endpoint
pendOpen map[flowtrack.Tuple]*pendingOpenFlow // see pendopen.go
// pongCallback is the map of response handlers waiting for disco or TSMP
// pong callbacks. The map key is a random slice of bytes.
pongCallback map[[8]byte]func(packet.TSMPPongReply)
// icmpEchoResponseCallback is the map of response handlers waiting for ICMP
// echo responses. The map key is a random uint32 that is the little endian
// value of the ICMP identifier and sequence number concatenated.
icmpEchoResponseCallback map[uint32]func()
// networkLogger logs statistics about network connections.
networkLogger netlog.Logger
// Lock ordering: magicsock.Conn.mu, wgLock, then mu.
}
// BIRDClient handles communication with the BIRD Internet Routing Daemon.
type BIRDClient interface {
EnableProtocol(proto string) error
DisableProtocol(proto string) error
Close() error
}
// Config is the engine configuration.
type Config struct {
// Tun is the device used by the Engine to exchange packets with
// the OS.
// If nil, a fake Device that does nothing is used.
Tun tun.Device
// IsTAP is whether Tun is actually a TAP (Layer 2) device that'll
// require ethernet headers.
IsTAP bool
// Router interfaces the Engine to the OS network stack.
// If nil, a fake Router that does nothing is used.
Router router.Router
// DNS interfaces the Engine to the OS DNS resolver configuration.
// If nil, a fake OSConfigurator that does nothing is used.
DNS dns.OSConfigurator
// NetMon optionally provides an existing network monitor to re-use.
// If nil, a new network monitor is created.
NetMon *netmon.Monitor
// Dialer is the dialer to use for outbound connections.
// If nil, a new Dialer is created
Dialer *tsdial.Dialer
// ControlKnobs is the set of control plane-provied knobs
// to use.
// If nil, defaults are used.
ControlKnobs *controlknobs.Knobs
// ListenPort is the port on which the engine will listen.
// If zero, a port is automatically selected.
ListenPort uint16
// RespondToPing determines whether this engine should internally
// reply to ICMP pings, without involving the OS.
// Used in "fake" mode for development.
RespondToPing bool
// BIRDClient, if non-nil, will be used to configure BIRD whenever
// this node is a primary subnet router.
BIRDClient BIRDClient
// SetSubsystem, if non-nil, is called for each new subsystem created, just before a successful return.
SetSubsystem func(any)
// TailFSForLocal, if populated, will cause the engine to expose a TailFS
// listener at 100.100.100.100:8080.
TailFSForLocal tailfs.FileSystemForLocal
}
// NewFakeUserspaceEngine returns a new userspace engine for testing.
//
// The opts may contain the following types:
//
// - int or uint16: to set the ListenPort.
func NewFakeUserspaceEngine(logf logger.Logf, opts ...any) (Engine, error) {
conf := Config{
RespondToPing: true,
}
for _, o := range opts {
switch v := o.(type) {
case uint16:
conf.ListenPort = v
case int:
if v < 0 || v > math.MaxUint16 {
return nil, fmt.Errorf("invalid ListenPort: %d", v)
}
conf.ListenPort = uint16(v)
case func(any):
conf.SetSubsystem = v
case *controlknobs.Knobs:
conf.ControlKnobs = v
default:
return nil, fmt.Errorf("unknown option type %T", v)
}
}
logf("Starting userspace WireGuard engine (with fake TUN device)")
return NewUserspaceEngine(logf, conf)
}
// NewUserspaceEngine creates the named tun device and returns a
// Tailscale Engine running on it.
func NewUserspaceEngine(logf logger.Logf, conf Config) (_ Engine, reterr error) {
var closePool closeOnErrorPool
defer closePool.closeAllIfError(&reterr)
if conf.Tun == nil {
logf("[v1] using fake (no-op) tun device")
conf.Tun = tstun.NewFake()
}
if conf.Router == nil {
logf("[v1] using fake (no-op) OS network configurator")
conf.Router = router.NewFake(logf)
}
if conf.DNS == nil {
logf("[v1] using fake (no-op) DNS configurator")
d, err := dns.NewNoopManager()
if err != nil {
return nil, err
}
conf.DNS = d
}
if conf.Dialer == nil {
conf.Dialer = &tsdial.Dialer{Logf: logf}
}
var tsTUNDev *tstun.Wrapper
if conf.IsTAP {
tsTUNDev = tstun.WrapTAP(logf, conf.Tun)
} else {
tsTUNDev = tstun.Wrap(logf, conf.Tun)
}
closePool.add(tsTUNDev)
e := &userspaceEngine{
timeNow: mono.Now,
logf: logf,
reqCh: make(chan struct{}, 1),
waitCh: make(chan struct{}),
tundev: tsTUNDev,
router: conf.Router,
confListenPort: conf.ListenPort,
birdClient: conf.BIRDClient,
controlKnobs: conf.ControlKnobs,
}
if e.birdClient != nil {
// Disable the protocol at start time.
if err := e.birdClient.DisableProtocol("tailscale"); err != nil {
return nil, err
}
}
e.isLocalAddr.Store(tsaddr.FalseContainsIPFunc())
e.isDNSIPOverTailscale.Store(tsaddr.FalseContainsIPFunc())
if conf.NetMon != nil {
e.netMon = conf.NetMon
} else {
mon, err := netmon.New(logf)
if err != nil {
return nil, err
}
closePool.add(mon)
e.netMon = mon
e.netMonOwned = true
}
tunName, _ := conf.Tun.Name()
conf.Dialer.SetTUNName(tunName)
conf.Dialer.SetNetMon(e.netMon)
e.dns = dns.NewManager(logf, conf.DNS, e.netMon, conf.Dialer, fwdDNSLinkSelector{e, tunName}, conf.ControlKnobs)
// TODO: there's probably a better place for this
sockstats.SetNetMon(e.netMon)
logf("link state: %+v", e.netMon.InterfaceState())
unregisterMonWatch := e.netMon.RegisterChangeCallback(func(delta *netmon.ChangeDelta) {
tshttpproxy.InvalidateCache()
e.linkChange(delta)
})
closePool.addFunc(unregisterMonWatch)
e.netMonUnregister = unregisterMonWatch
endpointsFn := func(endpoints []tailcfg.Endpoint) {
e.mu.Lock()
e.endpoints = append(e.endpoints[:0], endpoints...)
e.mu.Unlock()
e.RequestStatus()
}
onPortUpdate := func(port uint16, network string) {
e.logf("onPortUpdate(port=%v, network=%s)", port, network)
if err := e.router.UpdateMagicsockPort(port, network); err != nil {
e.logf("UpdateMagicsockPort(port=%v, network=%s) failed: %w", port, network, err)
}
}
magicsockOpts := magicsock.Options{
Logf: logf,
Port: conf.ListenPort,
EndpointsFunc: endpointsFn,
DERPActiveFunc: e.RequestStatus,
IdleFunc: e.tundev.IdleDuration,
NoteRecvActivity: e.noteRecvActivity,
NetMon: e.netMon,
ControlKnobs: conf.ControlKnobs,
OnPortUpdate: onPortUpdate,
PeerByKeyFunc: e.PeerByKey,
}
var err error
e.magicConn, err = magicsock.NewConn(magicsockOpts)
if err != nil {
return nil, fmt.Errorf("wgengine: %v", err)
}
closePool.add(e.magicConn)
e.magicConn.SetNetworkUp(e.netMon.InterfaceState().AnyInterfaceUp())
tsTUNDev.SetDiscoKey(e.magicConn.DiscoPublicKey())
if conf.RespondToPing {
e.tundev.PostFilterPacketInboundFromWireGuard = echoRespondToAll
}
e.tundev.PreFilterPacketOutboundToWireGuardEngineIntercept = e.handleLocalPackets
if envknob.BoolDefaultTrue("TS_DEBUG_CONNECT_FAILURES") {
if e.tundev.PreFilterPacketInboundFromWireGuard != nil {
return nil, errors.New("unexpected PreFilterIn already set")
}
e.tundev.PreFilterPacketInboundFromWireGuard = e.trackOpenPreFilterIn
if e.tundev.PostFilterPacketOutboundToWireGuard != nil {
return nil, errors.New("unexpected PostFilterOut already set")
}
e.tundev.PostFilterPacketOutboundToWireGuard = e.trackOpenPostFilterOut
}
e.wgLogger = wglog.NewLogger(logf)
e.tundev.OnTSMPPongReceived = func(pong packet.TSMPPongReply) {
e.mu.Lock()
defer e.mu.Unlock()
cb := e.pongCallback[pong.Data]
e.logf("wgengine: got TSMP pong %02x, peerAPIPort=%v; cb=%v", pong.Data, pong.PeerAPIPort, cb != nil)
if cb != nil {
go cb(pong)
}
}
e.tundev.OnICMPEchoResponseReceived = func(p *packet.Parsed) bool {
idSeq := p.EchoIDSeq()
e.mu.Lock()
defer e.mu.Unlock()
cb := e.icmpEchoResponseCallback[idSeq]
if cb == nil {
// We didn't swallow it, so let it flow to the host.
return false
}
e.logf("wgengine: got diagnostic ICMP response %02x", idSeq)
go cb()
return true
}
// wgdev takes ownership of tundev, will close it when closed.
e.logf("Creating WireGuard device...")
e.wgdev = wgcfg.NewDevice(e.tundev, e.magicConn.Bind(), e.wgLogger.DeviceLogger)
closePool.addFunc(e.wgdev.Close)
closePool.addFunc(func() {
if err := e.magicConn.Close(); err != nil {
e.logf("error closing magicconn: %v", err)
}
})
go func() {
up := false
for event := range e.tundev.EventsUpDown() {
if event&tun.EventUp != 0 && !up {
e.logf("external route: up")
e.RequestStatus()
up = true
}
if event&tun.EventDown != 0 && up {
e.logf("external route: down")
e.RequestStatus()
up = false
}
}
}()
go func() {
select {
case <-e.wgdev.Wait():
e.mu.Lock()
closing := e.closing
e.mu.Unlock()
if !closing {
e.logf("Closing the engine because the WireGuard device has been closed...")
e.Close()
}
case <-e.waitCh:
// continue
}
}()
e.logf("Bringing WireGuard device up...")
if err := e.wgdev.Up(); err != nil {
return nil, fmt.Errorf("wgdev.Up: %w", err)
}
e.logf("Bringing router up...")
if err := e.router.Up(); err != nil {
return nil, fmt.Errorf("router.Up: %w", err)
}
// It's a little pointless to apply no-op settings here (they
// should already be empty?), but it at least exercises the
// router implementation early on.
e.logf("Clearing router settings...")
if err := e.router.Set(nil); err != nil {
return nil, fmt.Errorf("router.Set(nil): %w", err)
}
e.logf("Starting network monitor...")
e.netMon.Start()
if conf.SetSubsystem != nil {
conf.SetSubsystem(e.tundev)
conf.SetSubsystem(e.magicConn)
conf.SetSubsystem(e.dns)
conf.SetSubsystem(conf.Router)
conf.SetSubsystem(conf.Dialer)
conf.SetSubsystem(e.netMon)
if conf.TailFSForLocal != nil {
conf.SetSubsystem(conf.TailFSForLocal)
}
}
e.logf("Engine created.")
return e, nil
}
// echoRespondToAll is an inbound post-filter responding to all echo requests.
func echoRespondToAll(p *packet.Parsed, t *tstun.Wrapper) filter.Response {
if p.IsEchoRequest() {
header := p.ICMP4Header()
header.ToResponse()
outp := packet.Generate(&header, p.Payload())
t.InjectOutbound(outp)
// We already responded to it, but it's not an error.
// Proceed with regular delivery. (Since this code is only
// used in fake mode, regular delivery just means throwing
// it away. If this ever gets run in non-fake mode, you'll
// get double responses to pings, which is an indicator you
// shouldn't be doing that I guess.)
return filter.Accept
}
return filter.Accept
}
// handleLocalPackets inspects packets coming from the local network
// stack, and intercepts any packets that should be handled by
// tailscaled directly. Other packets are allowed to proceed into the
// main ACL filter.
func (e *userspaceEngine) handleLocalPackets(p *packet.Parsed, t *tstun.Wrapper) filter.Response {
if runtime.GOOS == "darwin" || runtime.GOOS == "ios" {
isLocalAddr, ok := e.isLocalAddr.LoadOk()
if !ok {
e.logf("[unexpected] e.isLocalAddr was nil, can't check for loopback packet")
} else if isLocalAddr(p.Dst.Addr()) {
// macOS NetworkExtension directs packets destined to the
// tunnel's local IP address into the tunnel, instead of
// looping back within the kernel network stack. We have to
// notice that an outbound packet is actually destined for
// ourselves, and loop it back into macOS.
t.InjectInboundCopy(p.Buffer())
metricReflectToOS.Add(1)
return filter.Drop
}
}
return filter.Accept
}
var debugTrimWireguard = envknob.RegisterOptBool("TS_DEBUG_TRIM_WIREGUARD")
// forceFullWireguardConfig reports whether we should give wireguard our full
// network map, even for inactive peers.
//
// TODO(bradfitz): remove this at some point. We had a TODO to do it before 1.0
// but it's still there as of 1.30. Really we should not do this wireguard lazy
// peer config at all and just fix wireguard-go to not have so much extra memory
// usage per peer. That would simplify a lot of Tailscale code. OTOH, we have 50
// MB of memory on iOS now instead of 15 MB, so the other option is to just give
// up on lazy wireguard config and blow the memory and hope for the best on iOS.
// That's sad too. Or we get rid of these knobs (lazy wireguard config has been
// stable!) but I'm worried that a future regression would be easier to debug
// with these knobs in place.
func (e *userspaceEngine) forceFullWireguardConfig(numPeers int) bool {
// Did the user explicitly enable trimming via the environment variable knob?
if b, ok := debugTrimWireguard().Get(); ok {
return !b
}
return e.controlKnobs != nil && e.controlKnobs.KeepFullWGConfig.Load()
}
// isTrimmablePeer reports whether p is a peer that we can trim out of the
// network map.
//
// For implementation simplicity, we can only trim peers that have
// only non-subnet AllowedIPs (an IPv4 /32 or IPv6 /128), which is the
// common case for most peers. Subnet router nodes will just always be
// created in the wireguard-go config.
func (e *userspaceEngine) isTrimmablePeer(p *wgcfg.Peer, numPeers int) bool {
if e.forceFullWireguardConfig(numPeers) {
return false
}
// AllowedIPs must all be single IPs, not subnets.
for _, aip := range p.AllowedIPs {
if !aip.IsSingleIP() {
return false
}
}
return true
}
// noteRecvActivity is called by magicsock when a packet has been
// received for the peer with node key nk. Magicsock calls this no
// more than every 10 seconds for a given peer.
func (e *userspaceEngine) noteRecvActivity(nk key.NodePublic) {
e.wgLock.Lock()
defer e.wgLock.Unlock()
if _, ok := e.recvActivityAt[nk]; !ok {
// Not a trimmable peer we care about tracking. (See isTrimmablePeer)
if e.trimmedNodes[nk] {
e.logf("wgengine: [unexpected] noteReceiveActivity called on idle node %v that's not in recvActivityAt", nk.ShortString())
}
return
}
now := e.timeNow()
e.recvActivityAt[nk] = now
// As long as there's activity, periodically poll the engine to get
// stats for the far away side effect of
// ipn/ipnlocal.LocalBackend.parseWgStatusLocked to log activity, for
// use in various admin dashboards.
// This particularly matters on platforms without a connected GUI, as
// the GUIs generally poll this enough to cause that logging. But
// tailscaled alone did not, hence this.
if e.lastStatusPollTime.IsZero() || now.Sub(e.lastStatusPollTime) >= statusPollInterval {
e.lastStatusPollTime = now
go e.RequestStatus()
}
// If the last activity time jumped a bunch (say, at least
// half the idle timeout) then see if we need to reprogram
// WireGuard. This could probably be just
// lazyPeerIdleThreshold without the divide by 2, but
// maybeReconfigWireguardLocked is cheap enough to call every
// couple minutes (just not on every packet).
if e.trimmedNodes[nk] {
e.logf("wgengine: idle peer %v now active, reconfiguring WireGuard", nk.ShortString())
e.maybeReconfigWireguardLocked(nil)
}
}
// isActiveSinceLocked reports whether the peer identified by (nk, ip)
// has had a packet sent to or received from it since t.
//
// e.wgLock must be held.
func (e *userspaceEngine) isActiveSinceLocked(nk key.NodePublic, ip netip.Addr, t mono.Time) bool {
if e.recvActivityAt[nk].After(t) {
return true
}
timePtr, ok := e.sentActivityAt[ip]
if !ok {
return false
}
return timePtr.LoadAtomic().After(t)
}
// discoChanged are the set of peers whose disco keys have changed, implying they've restarted.
// If a peer is in this set and was previously in the live wireguard config,
// it needs to be first removed and then re-added to flush out its wireguard session key.
// If discoChanged is nil or empty, this extra removal step isn't done.
//
// e.wgLock must be held.
func (e *userspaceEngine) maybeReconfigWireguardLocked(discoChanged map[key.NodePublic]bool) error {
if hook := e.testMaybeReconfigHook; hook != nil {
hook()
return nil
}
full := e.lastCfgFull
e.wgLogger.SetPeers(full.Peers)
// Compute a minimal config to pass to wireguard-go
// based on the full config. Prune off all the peers
// and only add the active ones back.
min := full
min.Peers = make([]wgcfg.Peer, 0, e.lastNMinPeers)
// We'll only keep a peer around if it's been active in
// the past 5 minutes. That's more than WireGuard's key
// rotation time anyway so it's no harm if we remove it
// later if it's been inactive.
activeCutoff := e.timeNow().Add(-lazyPeerIdleThreshold)
// Not all peers can be trimmed from the network map (see
// isTrimmablePeer). For those that are trimmable, keep track of
// their NodeKey and Tailscale IPs. These are the ones we'll need
// to install tracking hooks for to watch their send/receive
// activity.
trackNodes := make([]key.NodePublic, 0, len(full.Peers))
trackIPs := make([]netip.Addr, 0, len(full.Peers))
// Don't re-alloc the map; the Go compiler optimizes map clears as of
// Go 1.11, so we can re-use the existing + allocated map.
if e.trimmedNodes != nil {
clear(e.trimmedNodes)
} else {
e.trimmedNodes = make(map[key.NodePublic]bool)
}
needRemoveStep := false
for i := range full.Peers {
p := &full.Peers[i]
nk := p.PublicKey
if !e.isTrimmablePeer(p, len(full.Peers)) {
min.Peers = append(min.Peers, *p)
if discoChanged[nk] {
needRemoveStep = true
}
continue
}
trackNodes = append(trackNodes, nk)
recentlyActive := false
for _, cidr := range p.AllowedIPs {
trackIPs = append(trackIPs, cidr.Addr())
recentlyActive = recentlyActive || e.isActiveSinceLocked(nk, cidr.Addr(), activeCutoff)
}
if recentlyActive {
min.Peers = append(min.Peers, *p)
if discoChanged[nk] {
needRemoveStep = true
}
} else {
e.trimmedNodes[nk] = true
}
}
e.lastNMinPeers = len(min.Peers)
if changed := deephash.Update(&e.lastEngineSigTrim, &struct {
WGConfig *wgcfg.Config
TrimmedNodes map[key.NodePublic]bool
TrackNodes []key.NodePublic
TrackIPs []netip.Addr
}{&min, e.trimmedNodes, trackNodes, trackIPs}); !changed {
return nil
}
e.updateActivityMapsLocked(trackNodes, trackIPs)
if needRemoveStep {
minner := min
minner.Peers = nil
numRemove := 0
for _, p := range min.Peers {
if discoChanged[p.PublicKey] {
numRemove++
continue
}
minner.Peers = append(minner.Peers, p)
}
if numRemove > 0 {
e.logf("wgengine: Reconfig: removing session keys for %d peers", numRemove)
if err := wgcfg.ReconfigDevice(e.wgdev, &minner, e.logf); err != nil {
e.logf("wgdev.Reconfig: %v", err)
return err
}
}
}
e.logf("wgengine: Reconfig: configuring userspace WireGuard config (with %d/%d peers)", len(min.Peers), len(full.Peers))
if err := wgcfg.ReconfigDevice(e.wgdev, &min, e.logf); err != nil {
e.logf("wgdev.Reconfig: %v", err)
return err
}
return nil
}
// updateActivityMapsLocked updates the data structures used for tracking the activity
// of wireguard peers that we might add/remove dynamically from the real config
// as given to wireguard-go.
//
// e.wgLock must be held.
func (e *userspaceEngine) updateActivityMapsLocked(trackNodes []key.NodePublic, trackIPs []netip.Addr) {
// Generate the new map of which nodekeys we want to track
// receive times for.
mr := map[key.NodePublic]mono.Time{} // TODO: only recreate this if set of keys changed
for _, nk := range trackNodes {
// Preserve old times in the new map, but also
// populate map entries for new trackNodes values with
// time.Time{} zero values. (Only entries in this map
// are tracked, so the Time zero values allow it to be
// tracked later)
mr[nk] = e.recvActivityAt[nk]
}
e.recvActivityAt = mr
oldTime := e.sentActivityAt
e.sentActivityAt = make(map[netip.Addr]*mono.Time, len(oldTime))
oldFunc := e.destIPActivityFuncs
e.destIPActivityFuncs = make(map[netip.Addr]func(), len(oldFunc))
updateFn := func(timePtr *mono.Time) func() {
return func() {
now := e.timeNow()
old := timePtr.LoadAtomic()
// How long's it been since we last sent a packet?
elapsed := now.Sub(old)
if old == 0 {
// For our first packet, old is 0, which has indeterminate meaning.
// Set elapsed to a big number (four score and seven years).
elapsed = 762642 * time.Hour
}
if elapsed >= packetSendTimeUpdateFrequency {
timePtr.StoreAtomic(now)
}
// On a big jump, assume we might no longer be in the wireguard
// config and go check.
if elapsed >= packetSendRecheckWireguardThreshold {
e.wgLock.Lock()
defer e.wgLock.Unlock()
e.maybeReconfigWireguardLocked(nil)
}
}
}
for _, ip := range trackIPs {
timePtr := oldTime[ip]
if timePtr == nil {
timePtr = new(mono.Time)
}
e.sentActivityAt[ip] = timePtr
fn := oldFunc[ip]
if fn == nil {
fn = updateFn(timePtr)
}
e.destIPActivityFuncs[ip] = fn
}
e.tundev.SetDestIPActivityFuncs(e.destIPActivityFuncs)
}
// hasOverlap checks if there is a IPPrefix which is common amongst the two
// provided slices.
func hasOverlap(aips, rips views.Slice[netip.Prefix]) bool {
for i := range aips.Len() {
aip := aips.At(i)
if views.SliceContains(rips, aip) {
return true
}
}
return false
}
func (e *userspaceEngine) Reconfig(cfg *wgcfg.Config, routerCfg *router.Config, dnsCfg *dns.Config) error {
if routerCfg == nil {
panic("routerCfg must not be nil")
}
if dnsCfg == nil {
panic("dnsCfg must not be nil")
}
e.isLocalAddr.Store(tsaddr.NewContainsIPFunc(views.SliceOf(routerCfg.LocalAddrs)))
e.wgLock.Lock()
defer e.wgLock.Unlock()
e.tundev.SetWGConfig(cfg)
e.lastDNSConfig = dnsCfg
peerSet := make(set.Set[key.NodePublic], len(cfg.Peers))
e.mu.Lock()
e.peerSequence = e.peerSequence[:0]
for _, p := range cfg.Peers {
e.peerSequence = append(e.peerSequence, p.PublicKey)
peerSet.Add(p.PublicKey)
}
nm := e.netMap
e.mu.Unlock()
listenPort := e.confListenPort
if e.controlKnobs != nil && e.controlKnobs.RandomizeClientPort.Load() {
listenPort = 0
}
peerMTUEnable := e.magicConn.ShouldPMTUD()
isSubnetRouter := false
if e.birdClient != nil && nm != nil && nm.SelfNode.Valid() {
isSubnetRouter = hasOverlap(nm.SelfNode.PrimaryRoutes(), nm.SelfNode.Hostinfo().RoutableIPs())
e.logf("[v1] Reconfig: hasOverlap(%v, %v) = %v; isSubnetRouter=%v lastIsSubnetRouter=%v",
nm.SelfNode.PrimaryRoutes(), nm.SelfNode.Hostinfo().RoutableIPs(),
isSubnetRouter, isSubnetRouter, e.lastIsSubnetRouter)
}
isSubnetRouterChanged := isSubnetRouter != e.lastIsSubnetRouter
engineChanged := deephash.Update(&e.lastEngineSigFull, cfg)
routerChanged := deephash.Update(&e.lastRouterSig, &struct {
RouterConfig *router.Config
DNSConfig *dns.Config
}{routerCfg, dnsCfg})
listenPortChanged := listenPort != e.magicConn.LocalPort()
peerMTUChanged := peerMTUEnable != e.magicConn.PeerMTUEnabled()
if !engineChanged && !routerChanged && !listenPortChanged && !isSubnetRouterChanged && !peerMTUChanged {
return ErrNoChanges
}
newLogIDs := cfg.NetworkLogging
oldLogIDs := e.lastCfgFull.NetworkLogging
netLogIDsNowValid := !newLogIDs.NodeID.IsZero() && !newLogIDs.DomainID.IsZero()
netLogIDsWasValid := !oldLogIDs.NodeID.IsZero() && !oldLogIDs.DomainID.IsZero()
netLogIDsChanged := netLogIDsNowValid && netLogIDsWasValid && newLogIDs != oldLogIDs
netLogRunning := netLogIDsNowValid && !routerCfg.Equal(&router.Config{})
if envknob.NoLogsNoSupport() {
netLogRunning = false
}
// TODO(bradfitz,danderson): maybe delete this isDNSIPOverTailscale
// field and delete the resolver.ForwardLinkSelector hook and
// instead have ipnlocal populate a map of DNS IP => linkName and
// put that in the *dns.Config instead, and plumb it down to the
// dns.Manager. Maybe also with isLocalAddr above.
e.isDNSIPOverTailscale.Store(tsaddr.NewContainsIPFunc(views.SliceOf(dnsIPsOverTailscale(dnsCfg, routerCfg))))
// See if any peers have changed disco keys, which means they've restarted.
// If so, we need to update the wireguard-go/device.Device in two phases:
// once without the node which has restarted, to clear its wireguard session key,
// and a second time with it.
discoChanged := make(map[key.NodePublic]bool)
{
prevEP := make(map[key.NodePublic]key.DiscoPublic)
for i := range e.lastCfgFull.Peers {
if p := &e.lastCfgFull.Peers[i]; !p.DiscoKey.IsZero() {
prevEP[p.PublicKey] = p.DiscoKey
}
}
for i := range cfg.Peers {
p := &cfg.Peers[i]
if p.DiscoKey.IsZero() {
continue
}
pub := p.PublicKey
if old, ok := prevEP[pub]; ok && old != p.DiscoKey {
discoChanged[pub] = true
e.logf("wgengine: Reconfig: %s changed from %q to %q", pub.ShortString(), old, p.DiscoKey)
}
}
}
e.lastCfgFull = *cfg.Clone()
// Tell magicsock about the new (or initial) private key
// (which is needed by DERP) before wgdev gets it, as wgdev
// will start trying to handshake, which we want to be able to
// go over DERP.
if err := e.magicConn.SetPrivateKey(cfg.PrivateKey); err != nil {
e.logf("wgengine: Reconfig: SetPrivateKey: %v", err)
}
e.magicConn.UpdatePeers(peerSet)
e.magicConn.SetPreferredPort(listenPort)
e.magicConn.UpdatePMTUD()
if err := e.maybeReconfigWireguardLocked(discoChanged); err != nil {
return err
}
// Shutdown the network logger because the IDs changed.
// Let it be started back up by subsequent logic.
if netLogIDsChanged && e.networkLogger.Running() {
e.logf("wgengine: Reconfig: shutting down network logger")
ctx, cancel := context.WithTimeout(context.Background(), networkLoggerUploadTimeout)
defer cancel()
if err := e.networkLogger.Shutdown(ctx); err != nil {
e.logf("wgengine: Reconfig: error shutting down network logger: %v", err)
}
}
// Startup the network logger.
// Do this before configuring the router so that we capture initial packets.
if netLogRunning && !e.networkLogger.Running() {
nid := cfg.NetworkLogging.NodeID
tid := cfg.NetworkLogging.DomainID
e.logf("wgengine: Reconfig: starting up network logger (node:%s tailnet:%s)", nid.Public(), tid.Public())
if err := e.networkLogger.Startup(cfg.NodeID, nid, tid, e.tundev, e.magicConn, e.netMon); err != nil {
e.logf("wgengine: Reconfig: error starting up network logger: %v", err)
}
e.networkLogger.ReconfigRoutes(routerCfg)
}
if routerChanged {
e.logf("wgengine: Reconfig: configuring router")
e.networkLogger.ReconfigRoutes(routerCfg)
err := e.router.Set(routerCfg)
health.SetRouterHealth(err)
if err != nil {
return err
}
// Keep DNS configuration after router configuration, as some
// DNS managers refuse to apply settings if the device has no
// assigned address.
e.logf("wgengine: Reconfig: configuring DNS")
err = e.dns.Set(*dnsCfg)
health.SetDNSHealth(err)
if err != nil {
return err
}
}
// Shutdown the network logger.
// Do this after configuring the router so that we capture final packets.
// This attempts to flush out any log messages and may block.
if !netLogRunning && e.networkLogger.Running() {
e.logf("wgengine: Reconfig: shutting down network logger")
ctx, cancel := context.WithTimeout(context.Background(), networkLoggerUploadTimeout)
defer cancel()
if err := e.networkLogger.Shutdown(ctx); err != nil {
e.logf("wgengine: Reconfig: error shutting down network logger: %v", err)
}
}
if isSubnetRouterChanged && e.birdClient != nil {
e.logf("wgengine: Reconfig: configuring BIRD")
var err error
if isSubnetRouter {
err = e.birdClient.EnableProtocol("tailscale")
} else {
err = e.birdClient.DisableProtocol("tailscale")
}
if err != nil {
// Log but don't fail here.
e.logf("wgengine: error configuring BIRD: %v", err)
} else {
e.lastIsSubnetRouter = isSubnetRouter
}
}
e.logf("[v1] wgengine: Reconfig done")
return nil
}
func (e *userspaceEngine) GetFilter() *filter.Filter {
return e.tundev.GetFilter()
}
func (e *userspaceEngine) SetFilter(filt *filter.Filter) {
e.tundev.SetFilter(filt)
}
func (e *userspaceEngine) SetStatusCallback(cb StatusCallback) {
e.mu.Lock()
defer e.mu.Unlock()
e.statusCallback = cb
}
func (e *userspaceEngine) getStatusCallback() StatusCallback {
e.mu.Lock()
defer e.mu.Unlock()
return e.statusCallback
}
var ErrEngineClosing = errors.New("engine closing; no status")
func (e *userspaceEngine) PeerByKey(pubKey key.NodePublic) (_ wgint.Peer, ok bool) {
e.wgLock.Lock()
dev := e.wgdev
e.wgLock.Unlock()
if dev == nil {
return wgint.Peer{}, false
}
peer := dev.LookupPeer(pubKey.Raw32())
if peer == nil {
return wgint.Peer{}, false
}
return wgint.PeerOf(peer), true
}
func (e *userspaceEngine) getPeerStatusLite(pk key.NodePublic) (status ipnstate.PeerStatusLite, ok bool) {
peer, ok := e.PeerByKey(pk)
if !ok {
return status, false
}
status.NodeKey = pk
status.RxBytes = int64(peer.RxBytes())
status.TxBytes = int64(peer.TxBytes())
status.LastHandshake = peer.LastHandshake()
return status, true
}
func (e *userspaceEngine) getStatus() (*Status, error) {
// Grab derpConns before acquiring wgLock to not violate lock ordering;
// the DERPs method acquires magicsock.Conn.mu.
// (See comment in userspaceEngine's declaration.)
derpConns := e.magicConn.DERPs()
e.mu.Lock()
closing := e.closing
peerKeys := slices.Clone(e.peerSequence)
localAddrs := slices.Clone(e.endpoints)
e.mu.Unlock()
if closing {
return nil, ErrEngineClosing
}
peers := make([]ipnstate.PeerStatusLite, 0, len(peerKeys))
for _, key := range peerKeys {
if status, ok := e.getPeerStatusLite(key); ok {
peers = append(peers, status)
}
}
return &Status{
AsOf: time.Now(),
LocalAddrs: localAddrs,
Peers: peers,
DERPs: derpConns,
}, nil
}
func (e *userspaceEngine) RequestStatus() {
// This is slightly tricky. e.getStatus() can theoretically get
// blocked inside wireguard for a while, and RequestStatus() is
// sometimes called from a goroutine, so we don't want a lot of
// them hanging around. On the other hand, requesting multiple
// status updates simultaneously is pointless anyway; they will
// all say the same thing.
// Enqueue at most one request. If one is in progress already, this
// adds one more to the queue. If one has been requested but not
// started, it is a no-op.
select {
case e.reqCh <- struct{}{}:
default:
}
// Dequeue at most one request. Another thread may have already
// dequeued the request we enqueued above, which is fine, since the
// information is guaranteed to be at least as recent as the current
// call to RequestStatus().
select {
case <-e.reqCh:
s, err := e.getStatus()
if s == nil && err == nil {
e.logf("[unexpected] RequestStatus: both s and err are nil")
return
}
if cb := e.getStatusCallback(); cb != nil {
cb(s, err)
}
default:
}
}
func (e *userspaceEngine) Close() {
e.mu.Lock()
if e.closing {
e.mu.Unlock()
return
}
e.closing = true
e.mu.Unlock()
r := bufio.NewReader(strings.NewReader(""))
e.wgdev.IpcSetOperation(r)
e.magicConn.Close()
e.netMonUnregister()
if e.netMonOwned {
e.netMon.Close()
}
e.dns.Down()
e.router.Close()
e.wgdev.Close()
e.tundev.Close()
if e.birdClient != nil {
e.birdClient.DisableProtocol("tailscale")
e.birdClient.Close()
}
close(e.waitCh)
ctx, cancel := context.WithTimeout(context.Background(), networkLoggerUploadTimeout)
defer cancel()
if err := e.networkLogger.Shutdown(ctx); err != nil {
e.logf("wgengine: Close: error shutting down network logger: %v", err)
}
}
func (e *userspaceEngine) Done() <-chan struct{} {
return e.waitCh
}
func (e *userspaceEngine) linkChange(delta *netmon.ChangeDelta) {
changed := delta.Major // TODO(bradfitz): ask more specific questions?
cur := delta.New
up := cur.AnyInterfaceUp()
if !up {
e.logf("LinkChange: all links down; pausing: %v", cur)
} else if changed {
e.logf("LinkChange: major, rebinding. New state: %v", cur)
} else {
e.logf("[v1] LinkChange: minor")
}
health.SetAnyInterfaceUp(up)
e.magicConn.SetNetworkUp(up)
if !up || changed {
if err := e.dns.FlushCaches(); err != nil {
e.logf("wgengine: dns flush failed after major link change: %v", err)
}
}
// Hacky workaround for Linux DNS issue 2458: on
// suspend/resume or whenever NetworkManager is started, it
// nukes all systemd-resolved configs. So reapply our DNS
// config on major link change.
if changed {
switch runtime.GOOS {
case "linux", "android", "ios", "darwin":
e.wgLock.Lock()
dnsCfg := e.lastDNSConfig
e.wgLock.Unlock()
if dnsCfg != nil {
if err := e.dns.Set(*dnsCfg); err != nil {
e.logf("wgengine: error setting DNS config after major link change: %v", err)
} else {
e.logf("wgengine: set DNS config again after major link change")
}
}
}
}
why := "link-change-minor"
if changed {
why = "link-change-major"
metricNumMajorChanges.Add(1)
e.magicConn.Rebind()
} else {
metricNumMinorChanges.Add(1)
}
e.magicConn.ReSTUN(why)
}
func (e *userspaceEngine) SetNetworkMap(nm *netmap.NetworkMap) {
e.magicConn.SetNetworkMap(nm)
e.mu.Lock()
e.netMap = nm
e.mu.Unlock()
}
func (e *userspaceEngine) UpdateStatus(sb *ipnstate.StatusBuilder) {
st, err := e.getStatus()
if err != nil {
e.logf("wgengine: getStatus: %v", err)
return
}
if sb.WantPeers {
for _, ps := range st.Peers {
sb.AddPeer(ps.NodeKey, &ipnstate.PeerStatus{
RxBytes: int64(ps.RxBytes),
TxBytes: int64(ps.TxBytes),
LastHandshake: ps.LastHandshake,
InEngine: true,
})
}
}
e.magicConn.UpdateStatus(sb)
}
func (e *userspaceEngine) Ping(ip netip.Addr, pingType tailcfg.PingType, size int, cb func(*ipnstate.PingResult)) {
res := &ipnstate.PingResult{IP: ip.String()}
pip, ok := e.PeerForIP(ip)
if !ok {
e.logf("ping(%v): no matching peer", ip)
res.Err = "no matching peer"
cb(res)
return
}
if pip.IsSelf {
res.Err = fmt.Sprintf("%v is local Tailscale IP", ip)
res.IsLocalIP = true
cb(res)
return
}
peer := pip.Node
e.logf("ping(%v): sending %v ping to %v %v ...", ip, pingType, peer.Key().ShortString(), peer.ComputedName())
switch pingType {
case "disco":
e.magicConn.Ping(peer, res, size, cb)
case "TSMP":
e.sendTSMPPing(ip, peer, res, cb)
case "ICMP":
e.sendICMPEchoRequest(ip, peer, res, cb)
}
}
func (e *userspaceEngine) mySelfIPMatchingFamily(dst netip.Addr) (src netip.Addr, err error) {
var zero netip.Addr
e.mu.Lock()
defer e.mu.Unlock()
if e.netMap == nil {
return zero, errors.New("no netmap")
}
addrs := e.netMap.GetAddresses()
if addrs.Len() == 0 {
return zero, errors.New("no self address in netmap")
}
for i := range addrs.Len() {
if a := addrs.At(i); a.IsSingleIP() && a.Addr().BitLen() == dst.BitLen() {
return a.Addr(), nil
}
}
return zero, errors.New("no self address in netmap matching address family")
}
func (e *userspaceEngine) sendICMPEchoRequest(destIP netip.Addr, peer tailcfg.NodeView, res *ipnstate.PingResult, cb func(*ipnstate.PingResult)) {
srcIP, err := e.mySelfIPMatchingFamily(destIP)
if err != nil {
res.Err = err.Error()
cb(res)
return
}
var icmph packet.Header
if srcIP.Is4() {
icmph = packet.ICMP4Header{
IP4Header: packet.IP4Header{
IPProto: ipproto.ICMPv4,
Src: srcIP,
Dst: destIP,
},
Type: packet.ICMP4EchoRequest,
Code: packet.ICMP4NoCode,
}
} else {
icmph = packet.ICMP6Header{
IP6Header: packet.IP6Header{
IPProto: ipproto.ICMPv6,
Src: srcIP,
Dst: destIP,
},
Type: packet.ICMP6EchoRequest,
Code: packet.ICMP6NoCode,
}
}
idSeq, payload := packet.ICMPEchoPayload(nil)
expireTimer := time.AfterFunc(10*time.Second, func() {
e.setICMPEchoResponseCallback(idSeq, nil)
})
t0 := time.Now()
e.setICMPEchoResponseCallback(idSeq, func() {
expireTimer.Stop()
d := time.Since(t0)
res.LatencySeconds = d.Seconds()
res.NodeIP = destIP.String()
res.NodeName = peer.ComputedName()
cb(res)
})
icmpPing := packet.Generate(icmph, payload)
e.tundev.InjectOutbound(icmpPing)
}
func (e *userspaceEngine) sendTSMPPing(ip netip.Addr, peer tailcfg.NodeView, res *ipnstate.PingResult, cb func(*ipnstate.PingResult)) {
srcIP, err := e.mySelfIPMatchingFamily(ip)
if err != nil {
res.Err = err.Error()
cb(res)
return
}
var iph packet.Header
if srcIP.Is4() {
iph = packet.IP4Header{
IPProto: ipproto.TSMP,
Src: srcIP,
Dst: ip,
}
} else {
iph = packet.IP6Header{
IPProto: ipproto.TSMP,
Src: srcIP,
Dst: ip,
}
}
var data [8]byte
crand.Read(data[:])
expireTimer := time.AfterFunc(10*time.Second, func() {
e.setTSMPPongCallback(data, nil)
})
t0 := time.Now()
e.setTSMPPongCallback(data, func(pong packet.TSMPPongReply) {
expireTimer.Stop()
d := time.Since(t0)
res.LatencySeconds = d.Seconds()
res.NodeIP = ip.String()
res.NodeName = peer.ComputedName()
res.PeerAPIPort = pong.PeerAPIPort
cb(res)
})
var tsmpPayload [9]byte
tsmpPayload[0] = byte(packet.TSMPTypePing)
copy(tsmpPayload[1:], data[:])
tsmpPing := packet.Generate(iph, tsmpPayload[:])
e.tundev.InjectOutbound(tsmpPing)
}
func (e *userspaceEngine) setTSMPPongCallback(data [8]byte, cb func(packet.TSMPPongReply)) {
e.mu.Lock()
defer e.mu.Unlock()
if e.pongCallback == nil {
e.pongCallback = map[[8]byte]func(packet.TSMPPongReply){}
}
if cb == nil {
delete(e.pongCallback, data)
} else {
e.pongCallback[data] = cb
}
}
func (e *userspaceEngine) setICMPEchoResponseCallback(idSeq uint32, cb func()) {
e.mu.Lock()
defer e.mu.Unlock()
if cb == nil {
delete(e.icmpEchoResponseCallback, idSeq)
} else {
mak.Set(&e.icmpEchoResponseCallback, idSeq, cb)
}
}
// PeerForIP returns the Node in the wireguard config
// that's responsible for handling the given IP address.
//
// If none is found in the wireguard config but one is found in
// the netmap, it's described in an error.
//
// peerForIP acquires both e.mu and e.wgLock, but neither at the same
// time.
func (e *userspaceEngine) PeerForIP(ip netip.Addr) (ret PeerForIP, ok bool) {
e.mu.Lock()
nm := e.netMap
e.mu.Unlock()
if nm == nil {
return ret, false
}
// Check for exact matches before looking for subnet matches.
// TODO(bradfitz): add maps for these. on NetworkMap?
for _, p := range nm.Peers {
for i := range p.Addresses().Len() {
a := p.Addresses().At(i)
if a.Addr() == ip && a.IsSingleIP() && tsaddr.IsTailscaleIP(ip) {
return PeerForIP{Node: p, Route: a}, true
}
}
}
addrs := nm.GetAddresses()
for i := range addrs.Len() {
if a := addrs.At(i); a.Addr() == ip && a.IsSingleIP() && tsaddr.IsTailscaleIP(ip) {
return PeerForIP{Node: nm.SelfNode, IsSelf: true, Route: a}, true
}
}
e.wgLock.Lock()
defer e.wgLock.Unlock()
// TODO(bradfitz): this is O(n peers). Add ART to netaddr?
var best netip.Prefix
var bestKey key.NodePublic
for _, p := range e.lastCfgFull.Peers {
for _, cidr := range p.AllowedIPs {
if !cidr.Contains(ip) {
continue
}
if !best.IsValid() || cidr.Bits() > best.Bits() {
best = cidr
bestKey = p.PublicKey
}
}
}
// And another pass. Probably better than allocating a map per peerForIP
// call. But TODO(bradfitz): add a lookup map to netmap.NetworkMap.
if !bestKey.IsZero() {
for _, p := range nm.Peers {
if p.Key() == bestKey {
return PeerForIP{Node: p, Route: best}, true
}
}
}
return ret, false
}
type closeOnErrorPool []func()
func (p *closeOnErrorPool) add(c io.Closer) { *p = append(*p, func() { c.Close() }) }
func (p *closeOnErrorPool) addFunc(fn func()) { *p = append(*p, fn) }
func (p closeOnErrorPool) closeAllIfError(errp *error) {
if *errp != nil {
for _, closeFn := range p {
closeFn()
}
}
}
// ipInPrefixes reports whether ip is in any of pp.
func ipInPrefixes(ip netip.Addr, pp []netip.Prefix) bool {
for _, p := range pp {
if p.Contains(ip) {
return true
}
}
return false
}
// dnsIPsOverTailscale returns the IPPrefixes of DNS resolver IPs that are
// routed over Tailscale. The returned value does not contain duplicates is
// not necessarily sorted.
func dnsIPsOverTailscale(dnsCfg *dns.Config, routerCfg *router.Config) (ret []netip.Prefix) {
m := map[netip.Addr]bool{}
add := func(resolvers []*dnstype.Resolver) {
for _, r := range resolvers {
ip, err := netip.ParseAddr(r.Addr)
if err != nil {
if ipp, err := netip.ParseAddrPort(r.Addr); err == nil {
ip = ipp.Addr()
} else {
continue
}
}
if ipInPrefixes(ip, routerCfg.Routes) && !ipInPrefixes(ip, routerCfg.LocalRoutes) {
m[ip] = true
}
}
}
add(dnsCfg.DefaultResolvers)
for _, resolvers := range dnsCfg.Routes {
add(resolvers)
}
ret = make([]netip.Prefix, 0, len(m))
for ip := range m {
ret = append(ret, netip.PrefixFrom(ip, ip.BitLen()))
}
return ret
}
// fwdDNSLinkSelector is userspaceEngine's resolver.ForwardLinkSelector, to pick
// which network interface to send DNS queries out of.
type fwdDNSLinkSelector struct {
ue *userspaceEngine
tunName string
}
func (ls fwdDNSLinkSelector) PickLink(ip netip.Addr) (linkName string) {
if ls.ue.isDNSIPOverTailscale.Load()(ip) {
return ls.tunName
}
return ""
}
var (
metricReflectToOS = clientmetric.NewCounter("packet_reflect_to_os")
metricNumMajorChanges = clientmetric.NewCounter("wgengine_major_changes")
metricNumMinorChanges = clientmetric.NewCounter("wgengine_minor_changes")
)
func (e *userspaceEngine) InstallCaptureHook(cb capture.Callback) {
e.tundev.InstallCaptureHook(cb)
e.magicConn.InstallCaptureHook(cb)
}