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wgengine/magicsock: avoid handshaking relay endpoints that are trusted (#16412)

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Changes to our src/address family can trigger blackholes.

This commit also adds a missing set of trustBestAddrUntil when setting
a UDP relay path as bestAddr.

Updates tailscale/corp#27502

Signed-off-by: Jordan Whited <jordan@tailscale.com>
This commit is contained in:
Jordan Whited
2025-06-30 12:12:57 -07:00
committed by GitHub
parent 2fc247573b
commit 47e77565c6
4 changed files with 130 additions and 63 deletions
Download Patch File Download Diff File Expand all files Collapse all files
wgengine/magicsock/endpoint.go
+37 -15
View File
@@ -100,25 +100,33 @@ type endpoint struct {
relayCapable bool // whether the node is capable of speaking via a [tailscale.com/net/udprelay.Server]
}
// relayEndpointReady determines whether the given relay addr should be
// installed as de.bestAddr. It is only called by [relayManager] once it has
// determined addr is functional via [disco.Pong] reception.
func (de *endpoint) relayEndpointReady(addr epAddr, latency time.Duration) {
// udpRelayEndpointReady determines whether the given relay [addrQuality] should
// be installed as de.bestAddr. It is only called by [relayManager] once it has
// determined maybeBest is functional via [disco.Pong] reception.
func (de *endpoint) udpRelayEndpointReady(maybeBest addrQuality) {
de.c.mu.Lock()
defer de.c.mu.Unlock()
de.mu.Lock()
defer de.mu.Unlock()
maybeBetter := addrQuality{addr, latency, pingSizeToPktLen(0, addr)}
if !betterAddr(maybeBetter, de.bestAddr) {
if maybeBest.relayServerDisco.Compare(de.bestAddr.relayServerDisco) == 0 {
// TODO(jwhited): add some observability for this case, e.g. did we
// flip transports during a de.bestAddr transition from untrusted to
// trusted?
//
// If these are equal we must set maybeBest as bestAddr, otherwise we
// could leave a stale bestAddr if it goes over a different
// address family or src.
} else if !betterAddr(maybeBest, de.bestAddr) {
return
}
// Promote maybeBetter to bestAddr.
// Promote maybeBest to bestAddr.
// TODO(jwhited): collapse path change logging with endpoint.handlePongConnLocked()
de.c.logf("magicsock: disco: node %v %v now using %v mtu=%v", de.publicKey.ShortString(), de.discoShort(), maybeBetter.epAddr, maybeBetter.wireMTU)
de.setBestAddrLocked(maybeBetter)
de.c.peerMap.setNodeKeyForEpAddr(addr, de.publicKey)
de.c.logf("magicsock: disco: node %v %v now using %v mtu=%v", de.publicKey.ShortString(), de.discoShort(), maybeBest.epAddr, maybeBest.wireMTU)
de.setBestAddrLocked(maybeBest)
de.trustBestAddrUntil = mono.Now().Add(trustUDPAddrDuration)
de.c.peerMap.setNodeKeyForEpAddr(maybeBest.epAddr, de.publicKey)
}
func (de *endpoint) setBestAddrLocked(v addrQuality) {
@@ -871,7 +879,9 @@ func (de *endpoint) discoverUDPRelayPathsLocked(now mono.Time) {
// TODO(jwhited): return early if there are no relay servers set, otherwise
// we spin up and down relayManager.runLoop unnecessarily.
de.lastUDPRelayPathDiscovery = now
de.c.relayManager.allocateAndHandshakeAllServers(de)
lastBest := de.bestAddr
lastBestIsTrusted := mono.Now().Before(de.trustBestAddrUntil)
de.c.relayManager.startUDPRelayPathDiscoveryFor(de, lastBest, lastBestIsTrusted)
}
// wantUDPRelayPathDiscoveryLocked reports whether we should kick off UDP relay
@@ -1714,7 +1724,16 @@ func (de *endpoint) handlePongConnLocked(m *disco.Pong, di *discoInfo, src epAdd
// Promote this pong response to our current best address if it's lower latency.
// TODO(bradfitz): decide how latency vs. preference order affects decision
if !isDerp {
thisPong := addrQuality{sp.to, latency, tstun.WireMTU(pingSizeToPktLen(sp.size, sp.to))}
thisPong := addrQuality{
epAddr: sp.to,
latency: latency,
wireMTU: pingSizeToPktLen(sp.size, sp.to),
}
// TODO(jwhited): consider checking de.trustBestAddrUntil as well. If
// de.bestAddr is untrusted we may want to clear it, otherwise we could
// get stuck with a forever untrusted bestAddr that blackholes, since
// we don't clear direct UDP paths on disco ping timeout (see
// discoPingTimeout).
if betterAddr(thisPong, de.bestAddr) {
if src.vni.isSet() {
// This would be unexpected. Switching to a Geneve-encapsulated
@@ -1765,14 +1784,17 @@ func (e epAddr) String() string {
return fmt.Sprintf("%v:vni:%d", e.ap.String(), e.vni.get())
}
// addrQuality is an [epAddr] with an associated latency and path mtu.
// addrQuality is an [epAddr], an optional [key.DiscoPublic] if a relay server
// is associated, a round-trip latency measurement, and path mtu.
type addrQuality struct {
epAddr
latency time.Duration
wireMTU tstun.WireMTU
relayServerDisco key.DiscoPublic // only relevant if epAddr.vni.isSet(), otherwise zero value
latency time.Duration
wireMTU tstun.WireMTU
}
func (a addrQuality) String() string {
// TODO(jwhited): consider including relayServerDisco
return fmt.Sprintf("%v@%v+%v", a.epAddr, a.latency, a.wireMTU)
}
wgengine/magicsock/magicsock.go
+4 -2
View File
@@ -2137,6 +2137,8 @@ func (c *Conn) handleDiscoMessage(msg []byte, src epAddr, shouldBeRelayHandshake
}
ep.mu.Lock()
relayCapable := ep.relayCapable
lastBest := ep.bestAddr
lastBestIsTrusted := mono.Now().Before(ep.trustBestAddrUntil)
ep.mu.Unlock()
if isVia && !relayCapable {
c.logf("magicsock: disco: ignoring %s from %v; %v is not known to be relay capable", msgType, sender.ShortString(), sender.ShortString())
@@ -2156,7 +2158,7 @@ func (c *Conn) handleDiscoMessage(msg []byte, src epAddr, shouldBeRelayHandshake
c.discoShort, epDisco.short, via.ServerDisco.ShortString(),
ep.publicKey.ShortString(), derpStr(src.String()),
len(via.AddrPorts))
c.relayManager.handleCallMeMaybeVia(ep, via)
c.relayManager.handleCallMeMaybeVia(ep, lastBest, lastBestIsTrusted, via)
} else {
c.dlogf("[v1] magicsock: disco: %v<-%v (%v, %v) got call-me-maybe, %d endpoints",
c.discoShort, epDisco.short,
@@ -2254,7 +2256,7 @@ func (c *Conn) handlePingLocked(dm *disco.Ping, src epAddr, di *discoInfo, derpN
// We have no [endpoint] in the [peerMap] for this relay [epAddr]
// using it as a bestAddr. [relayManager] might be in the middle of
// probing it or attempting to set it as best via
// [endpoint.relayEndpointReady()]. Make [relayManager] aware.
// [endpoint.udpRelayEndpointReady()]. Make [relayManager] aware.
c.relayManager.handleGeneveEncapDiscoMsgNotBestAddr(c, dm, di, src)
return
}
wgengine/magicsock/relaymanager.go
+87 -44
View File
@@ -50,7 +50,7 @@ type relayManager struct {
// ===================================================================
// The following chan fields serve event inputs to a single goroutine,
// runLoop().
allocateHandshakeCh chan *endpoint
startDiscoveryCh chan endpointWithLastBest
allocateWorkDoneCh chan relayEndpointAllocWorkDoneEvent
handshakeWorkDoneCh chan relayEndpointHandshakeWorkDoneEvent
cancelWorkCh chan *endpoint
@@ -77,8 +77,8 @@ type serverDiscoVNI struct {
// relayHandshakeWork serves to track in-progress relay handshake work for a
// [udprelay.ServerEndpoint]. This structure is immutable once initialized.
type relayHandshakeWork struct {
ep *endpoint
se udprelay.ServerEndpoint
wlb endpointWithLastBest
se udprelay.ServerEndpoint
// handshakeServerEndpoint() always writes to doneCh (len 1) when it
// returns. It may end up writing the same event afterward to
@@ -97,7 +97,7 @@ type relayHandshakeWork struct {
// [disco.CallMeMaybeVia] reception. This structure is immutable once
// initialized.
type newRelayServerEndpointEvent struct {
ep *endpoint
wlb endpointWithLastBest
se udprelay.ServerEndpoint
server netip.AddrPort // zero value if learned via [disco.CallMeMaybeVia]
}
@@ -142,9 +142,9 @@ func (r *relayManager) runLoop() {
for {
select {
case ep := <-r.allocateHandshakeCh:
if !r.hasActiveWorkForEndpointRunLoop(ep) {
r.allocateAllServersRunLoop(ep)
case startDiscovery := <-r.startDiscoveryCh:
if !r.hasActiveWorkForEndpointRunLoop(startDiscovery.ep) {
r.allocateAllServersRunLoop(startDiscovery)
}
if !r.hasActiveWorkRunLoop() {
return
@@ -153,7 +153,7 @@ func (r *relayManager) runLoop() {
work, ok := r.allocWorkByEndpoint[done.work.ep]
if ok && work == done.work {
// Verify the work in the map is the same as the one that we're
// cleaning up. New events on r.allocateHandshakeCh can
// cleaning up. New events on r.startDiscoveryCh can
// overwrite pre-existing keys.
delete(r.allocWorkByEndpoint, done.work.ep)
}
@@ -237,7 +237,7 @@ func (r *relayManager) init() {
r.handshakeWorkByServerDiscoVNI = make(map[serverDiscoVNI]*relayHandshakeWork)
r.handshakeWorkAwaitingPong = make(map[*relayHandshakeWork]addrPortVNI)
r.addrPortVNIToHandshakeWork = make(map[addrPortVNI]*relayHandshakeWork)
r.allocateHandshakeCh = make(chan *endpoint)
r.startDiscoveryCh = make(chan endpointWithLastBest)
r.allocateWorkDoneCh = make(chan relayEndpointAllocWorkDoneEvent)
r.handshakeWorkDoneCh = make(chan relayEndpointHandshakeWorkDoneEvent)
r.cancelWorkCh = make(chan *endpoint)
@@ -273,7 +273,7 @@ func (r *relayManager) ensureDiscoInfoFor(work *relayHandshakeWork) {
di.di = &discoInfo{
discoKey: work.se.ServerDisco,
discoShort: work.se.ServerDisco.ShortString(),
sharedKey: work.ep.c.discoPrivate.Shared(work.se.ServerDisco),
sharedKey: work.wlb.ep.c.discoPrivate.Shared(work.se.ServerDisco),
}
}
}
@@ -306,7 +306,7 @@ func (r *relayManager) discoInfo(serverDisco key.DiscoPublic) (_ *discoInfo, ok
return nil, false
}
func (r *relayManager) handleCallMeMaybeVia(ep *endpoint, dm *disco.CallMeMaybeVia) {
func (r *relayManager) handleCallMeMaybeVia(ep *endpoint, lastBest addrQuality, lastBestIsTrusted bool, dm *disco.CallMeMaybeVia) {
se := udprelay.ServerEndpoint{
ServerDisco: dm.ServerDisco,
LamportID: dm.LamportID,
@@ -316,7 +316,11 @@ func (r *relayManager) handleCallMeMaybeVia(ep *endpoint, dm *disco.CallMeMaybeV
se.BindLifetime.Duration = dm.BindLifetime
se.SteadyStateLifetime.Duration = dm.SteadyStateLifetime
relayManagerInputEvent(r, nil, &r.newServerEndpointCh, newRelayServerEndpointEvent{
ep: ep,
wlb: endpointWithLastBest{
ep: ep,
lastBest: lastBest,
lastBestIsTrusted: lastBestIsTrusted,
},
se: se,
})
}
@@ -360,11 +364,19 @@ func relayManagerInputEvent[T any](r *relayManager, ctx context.Context, eventCh
}
}
// allocateAndHandshakeAllServers kicks off allocation and handshaking of relay
// endpoints for 'ep' on all known relay servers if there is no outstanding
// work.
func (r *relayManager) allocateAndHandshakeAllServers(ep *endpoint) {
relayManagerInputEvent(r, nil, &r.allocateHandshakeCh, ep)
// endpointWithLastBest represents an [*endpoint], its last bestAddr, and if
// the last bestAddr was trusted (see endpoint.trustBestAddrUntil) at the time
// of init. This structure is immutable once initialized.
type endpointWithLastBest struct {
ep *endpoint
lastBest addrQuality
lastBestIsTrusted bool
}
// startUDPRelayPathDiscoveryFor starts UDP relay path discovery for ep on all
// known relay servers if ep has no in-progress work.
func (r *relayManager) startUDPRelayPathDiscoveryFor(ep *endpoint, lastBest addrQuality, lastBestIsTrusted bool) {
relayManagerInputEvent(r, nil, &r.startDiscoveryCh, endpointWithLastBest{ep, lastBest, lastBestIsTrusted})
}
// stopWork stops all outstanding allocation & handshaking work for 'ep'.
@@ -432,7 +444,7 @@ func (r *relayManager) handleRxHandshakeDiscoMsgRunLoop(event relayHandshakeDisc
r.addrPortVNIToHandshakeWork[apv] = work
case *disco.Ping:
// Always TX a pong. We might not have any associated work if ping
// reception raced with our call to [endpoint.relayEndpointReady()], so
// reception raced with our call to [endpoint.udpRelayEndpointReady()], so
// err on the side of enabling the remote side to use this path.
//
// Conn.handlePingLocked() makes efforts to suppress duplicate pongs
@@ -473,7 +485,7 @@ func (r *relayManager) handleRxHandshakeDiscoMsgRunLoop(event relayHandshakeDisc
}
func (r *relayManager) handleHandshakeWorkDoneRunLoop(done relayEndpointHandshakeWorkDoneEvent) {
byServerDisco, ok := r.handshakeWorkByEndpointByServerDisco[done.work.ep]
byServerDisco, ok := r.handshakeWorkByEndpointByServerDisco[done.work.wlb.ep]
if !ok {
return
}
@@ -483,7 +495,7 @@ func (r *relayManager) handleHandshakeWorkDoneRunLoop(done relayEndpointHandshak
}
delete(byServerDisco, done.work.se.ServerDisco)
if len(byServerDisco) == 0 {
delete(r.handshakeWorkByEndpointByServerDisco, done.work.ep)
delete(r.handshakeWorkByEndpointByServerDisco, done.work.wlb.ep)
}
delete(r.handshakeWorkByServerDiscoVNI, serverDiscoVNI{done.work.se.ServerDisco, done.work.se.VNI})
apv, ok := r.handshakeWorkAwaitingPong[work]
@@ -499,10 +511,15 @@ func (r *relayManager) handleHandshakeWorkDoneRunLoop(done relayEndpointHandshak
vni := virtualNetworkID{}
vni.set(done.work.se.VNI)
addr := epAddr{ap: done.pongReceivedFrom, vni: vni}
// ep.relayEndpointReady() must be called in a new goroutine to prevent
// ep.udpRelayEndpointReady() must be called in a new goroutine to prevent
// deadlocks as it acquires [endpoint] & [Conn] mutexes. See [relayManager]
// docs for details.
go done.work.ep.relayEndpointReady(addr, done.latency)
go done.work.wlb.ep.udpRelayEndpointReady(addrQuality{
epAddr: addr,
relayServerDisco: done.work.se.ServerDisco,
latency: done.latency,
wireMTU: pingSizeToPktLen(0, addr),
})
}
func (r *relayManager) handleNewServerEndpointRunLoop(newServerEndpoint newRelayServerEndpointEvent) {
@@ -525,7 +542,7 @@ func (r *relayManager) handleNewServerEndpointRunLoop(newServerEndpoint newRelay
}
// Check for duplicate work by [*endpoint] + server disco.
byServerDisco, ok := r.handshakeWorkByEndpointByServerDisco[newServerEndpoint.ep]
byServerDisco, ok := r.handshakeWorkByEndpointByServerDisco[newServerEndpoint.wlb.ep]
if ok {
existingWork, ok := byServerDisco[newServerEndpoint.se.ServerDisco]
if ok {
@@ -569,10 +586,40 @@ func (r *relayManager) handleNewServerEndpointRunLoop(newServerEndpoint newRelay
}
}
if newServerEndpoint.server.IsValid() {
// Send a [disco.CallMeMaybeVia] to the remote peer if we allocated this
// endpoint, regardless of if we start a handshake below.
go r.sendCallMeMaybeVia(newServerEndpoint.wlb.ep, newServerEndpoint.se)
}
lastBestMatchingServer := newServerEndpoint.se.ServerDisco.Compare(newServerEndpoint.wlb.lastBest.relayServerDisco) == 0
if lastBestMatchingServer && newServerEndpoint.wlb.lastBestIsTrusted {
// This relay server endpoint is the same as [endpoint]'s bestAddr at
// the time UDP relay path discovery was started, and it was also a
// trusted path (see endpoint.trustBestAddrUntil), so return early.
//
// If we were to start a new handshake, there is a chance that we
// cause [endpoint] to blackhole some packets on its bestAddr if we end
// up shifting to a new address family or src, e.g. IPv4 to IPv6, due to
// the window of time between the handshake completing, and our call to
// udpRelayEndpointReady(). The relay server can only forward packets
// from us on a single [epAddr].
return
}
// TODO(jwhited): if lastBest is untrusted, consider some strategies
// to reduce the chance we blackhole if it were to transition to
// trusted during/before the new handshake:
// 1. Start by attempting a handshake with only lastBest.epAddr. If
// that fails then try the remaining [epAddr]s.
// 2. Signal bestAddr trust transitions between [endpoint] and
// [relayManager] in order to prevent a handshake from starting
// and/or stop one that is running.
// We're ready to start a new handshake.
ctx, cancel := context.WithCancel(context.Background())
work := &relayHandshakeWork{
ep: newServerEndpoint.ep,
wlb: newServerEndpoint.wlb,
se: newServerEndpoint.se,
rxDiscoMsgCh: make(chan relayHandshakeDiscoMsgEvent),
doneCh: make(chan relayEndpointHandshakeWorkDoneEvent, 1),
@@ -581,16 +628,11 @@ func (r *relayManager) handleNewServerEndpointRunLoop(newServerEndpoint newRelay
}
if byServerDisco == nil {
byServerDisco = make(map[key.DiscoPublic]*relayHandshakeWork)
r.handshakeWorkByEndpointByServerDisco[newServerEndpoint.ep] = byServerDisco
r.handshakeWorkByEndpointByServerDisco[newServerEndpoint.wlb.ep] = byServerDisco
}
byServerDisco[newServerEndpoint.se.ServerDisco] = work
r.handshakeWorkByServerDiscoVNI[sdv] = work
if newServerEndpoint.server.IsValid() {
// Send CallMeMaybeVia to the remote peer if we allocated this endpoint.
go r.sendCallMeMaybeVia(work.ep, work.se)
}
r.handshakeGeneration++
if r.handshakeGeneration == 0 { // generation must be nonzero
r.handshakeGeneration++
@@ -633,7 +675,8 @@ func (r *relayManager) handshakeServerEndpoint(work *relayHandshakeWork, generat
work.cancel()
}()
epDisco := work.ep.disco.Load()
ep := work.wlb.ep
epDisco := ep.disco.Load()
if epDisco == nil {
return
}
@@ -653,7 +696,7 @@ func (r *relayManager) handshakeServerEndpoint(work *relayHandshakeWork, generat
for _, addrPort := range work.se.AddrPorts {
if addrPort.IsValid() {
sentBindAny = true
go work.ep.c.sendDiscoMessage(epAddr{ap: addrPort, vni: vni}, key.NodePublic{}, work.se.ServerDisco, bind, discoVerboseLog)
go ep.c.sendDiscoMessage(epAddr{ap: addrPort, vni: vni}, key.NodePublic{}, work.se.ServerDisco, bind, discoVerboseLog)
}
}
if !sentBindAny {
@@ -684,15 +727,15 @@ func (r *relayManager) handshakeServerEndpoint(work *relayHandshakeWork, generat
sentPingAt[txid] = time.Now()
ping := &disco.Ping{
TxID: txid,
NodeKey: work.ep.c.publicKeyAtomic.Load(),
NodeKey: ep.c.publicKeyAtomic.Load(),
}
go func() {
if withAnswer != nil {
answer := &disco.BindUDPRelayEndpointAnswer{BindUDPRelayEndpointCommon: common}
answer.Challenge = *withAnswer
work.ep.c.sendDiscoMessage(epAddr{ap: to, vni: vni}, key.NodePublic{}, work.se.ServerDisco, answer, discoVerboseLog)
ep.c.sendDiscoMessage(epAddr{ap: to, vni: vni}, key.NodePublic{}, work.se.ServerDisco, answer, discoVerboseLog)
}
work.ep.c.sendDiscoMessage(epAddr{ap: to, vni: vni}, key.NodePublic{}, epDisco.key, ping, discoVerboseLog)
ep.c.sendDiscoMessage(epAddr{ap: to, vni: vni}, key.NodePublic{}, epDisco.key, ping, discoVerboseLog)
}()
}
@@ -760,17 +803,17 @@ func (r *relayManager) handshakeServerEndpoint(work *relayHandshakeWork, generat
}
}
func (r *relayManager) allocateAllServersRunLoop(ep *endpoint) {
func (r *relayManager) allocateAllServersRunLoop(wlb endpointWithLastBest) {
if len(r.serversByAddrPort) == 0 {
return
}
ctx, cancel := context.WithCancel(context.Background())
started := &relayEndpointAllocWork{ep: ep, cancel: cancel, wg: &sync.WaitGroup{}}
started := &relayEndpointAllocWork{ep: wlb.ep, cancel: cancel, wg: &sync.WaitGroup{}}
for k := range r.serversByAddrPort {
started.wg.Add(1)
go r.allocateSingleServer(ctx, started.wg, k, ep)
go r.allocateSingleServer(ctx, started.wg, k, wlb)
}
r.allocWorkByEndpoint[ep] = started
r.allocWorkByEndpoint[wlb.ep] = started
go func() {
started.wg.Wait()
relayManagerInputEvent(r, ctx, &r.allocateWorkDoneCh, relayEndpointAllocWorkDoneEvent{work: started})
@@ -829,25 +872,25 @@ func doAllocate(ctx context.Context, server netip.AddrPort, discoKeys [2]key.Dis
}
}
func (r *relayManager) allocateSingleServer(ctx context.Context, wg *sync.WaitGroup, server netip.AddrPort, ep *endpoint) {
func (r *relayManager) allocateSingleServer(ctx context.Context, wg *sync.WaitGroup, server netip.AddrPort, wlb endpointWithLastBest) {
// TODO(jwhited): introduce client metrics counters for notable failures
defer wg.Done()
remoteDisco := ep.disco.Load()
remoteDisco := wlb.ep.disco.Load()
if remoteDisco == nil {
return
}
firstTry := true
for {
se, err := doAllocate(ctx, server, [2]key.DiscoPublic{ep.c.discoPublic, remoteDisco.key})
se, err := doAllocate(ctx, server, [2]key.DiscoPublic{wlb.ep.c.discoPublic, remoteDisco.key})
if err == nil {
relayManagerInputEvent(r, ctx, &r.newServerEndpointCh, newRelayServerEndpointEvent{
ep: ep,
wlb: wlb,
se: se,
server: server, // we allocated this endpoint (vs CallMeMaybeVia reception), mark it as such
})
return
}
ep.c.logf("[v1] magicsock: relayManager: error allocating endpoint on %v for %v: %v", server, ep.discoShort(), err)
wlb.ep.c.logf("[v1] magicsock: relayManager: error allocating endpoint on %v for %v: %v", server, wlb.ep.discoShort(), err)
var notReady errNotReady
if firstTry && errors.As(err, &notReady) {
select {
wgengine/magicsock/relaymanager_test.go
+2 -2
View File
@@ -14,7 +14,7 @@ import (
func TestRelayManagerInitAndIdle(t *testing.T) {
rm := relayManager{}
rm.allocateAndHandshakeAllServers(&endpoint{})
rm.startUDPRelayPathDiscoveryFor(&endpoint{}, addrQuality{}, false)
<-rm.runLoopStoppedCh
rm = relayManager{}
@@ -22,7 +22,7 @@ func TestRelayManagerInitAndIdle(t *testing.T) {
<-rm.runLoopStoppedCh
rm = relayManager{}
rm.handleCallMeMaybeVia(&endpoint{c: &Conn{discoPrivate: key.NewDisco()}}, &disco.CallMeMaybeVia{ServerDisco: key.NewDisco().Public()})
rm.handleCallMeMaybeVia(&endpoint{c: &Conn{discoPrivate: key.NewDisco()}}, addrQuality{}, false, &disco.CallMeMaybeVia{ServerDisco: key.NewDisco().Public()})
<-rm.runLoopStoppedCh
rm = relayManager{}