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wgengine/magicsock: send, use endpoints in CallMeMaybe messages

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Fixes #1172

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
pull/1180/head
Brad Fitzpatrick 3 years ago committed by Brad Fitzpatrick
parent ec77b80c53
commit edf64e0901
2 changed files with 78 additions and 17 deletions
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22
disco/disco.go
Unescape Escape View File

@ -124,13 +124,21 @@ func parsePing(ver uint8, p []byte) (m *Ping, err error) {
// happy with its path. But usually it will.
type CallMeMaybe struct {
// MyNumber is what the peer believes its endpoints are.
// Tailscale clients before 1.4 did not populate this
// so these values should merely augment whetever the control
// server sends. But because the client could've been idle
// before it reached out to us, the control plane might
// have stale info and these endpoints in CallMeMaybe
// might contain the just-obtained-milliseconds-ago
// STUN endpoint.
//
// Prior to Tailscale 1.4, the endpoints were exchanged purely
// between nodes and the control server.
//
// Starting with Tailscale 1.4, clients advertise their endpoints.
// Older clients won't use this, but newer clients should
// use any endpoints in here that aren't included from control.
//
// Control might have sent stale endpoints if the client was idle
// before contacting us. In that case, the client likely did a STUN
// request immediately before sending the CallMeMaybe to recreate
// their NAT port mapping, and that new good endpoint is included
// in this field, but might not yet be in control's endpoints.
// (And in the future, control will stop distributing endpoints
// when clients are suitably new.)
MyNumber []netaddr.IPPort
}

73
wgengine/magicsock/magicsock.go
Unescape Escape View File

@ -1851,7 +1851,7 @@ func (c *Conn) handleDiscoMessage(msg []byte, src netaddr.IPPort) bool {
}
if de != nil {
c.logf("magicsock: disco: %v<-%v (%v, %v) got call-me-maybe", c.discoShort, de.discoShort, de.publicKey.ShortString(), derpStr(src.String()))
go de.handleCallMeMaybe()
go de.handleCallMeMaybe(dm)
}
}
@ -1882,6 +1882,29 @@ func (c *Conn) handlePingLocked(dm *disco.Ping, de *discoEndpoint, src netaddr.I
}, discoVerboseLog)
}
// enqueueCallMeMaybe schedules a send of disco.CallMeMaybe to de via derpAddr
// once we know that our STUN endpoint is fresh.
//
// derpAddr is de.derpAddr at the time of send. It's assumed the peer won't be
// flipping primary DERPs in the 0-30ms it takes to confirm our STUN endpoint.
// If they do, traffic will just go over DERP for a bit longer until the next
// discovery round.
func (c *Conn) enqueueCallMeMaybe(derpAddr netaddr.IPPort, de *discoEndpoint) {
c.mu.Lock()
defer c.mu.Unlock()
// TODO(bradfitz): do a fast/lite re-STUN if our STUN info is too old
// Currently there's no "queue" despite the method name. There will be.
eps := make([]netaddr.IPPort, 0, len(c.lastEndpoints))
for _, ep := range c.lastEndpoints {
if ipp, err := netaddr.ParseIPPort(ep); err == nil {
eps = append(eps, ipp)
}
}
go de.sendDiscoMessage(derpAddr, &disco.CallMeMaybe{MyNumber: eps}, discoLog)
}
// setAddrToDiscoLocked records that newk is at src.
//
// c.mu must be held.
@ -2841,6 +2864,7 @@ type discoEndpoint struct {
trustBestAddrUntil time.Time // time when bestAddr expires
sentPing map[stun.TxID]sentPing
endpointState map[netaddr.IPPort]*endpointState
isCallMeMaybeEP map[netaddr.IPPort]bool
pendingCLIPings []pendingCLIPing // any outstanding "tailscale ping" commands running
}
@ -2905,6 +2929,10 @@ type endpointState struct {
// updated and use it to discard old candidates.
lastGotPing time.Time
// callMeMaybeTime, if non-zero, is the time this endpoint
// was advertised last via a call-me-maybe disco message.
callMeMaybeTime time.Time
recentPongs []pongReply // ring buffer up to pongHistoryCount entries
recentPong uint16 // index into recentPongs of most recent; older before, wrapped
@ -2918,11 +2946,13 @@ const indexSentinelDeleted = -1
// shouldDeleteLocked reports whether we should delete this endpoint.
func (st *endpointState) shouldDeleteLocked() bool {
switch {
case !st.callMeMaybeTime.IsZero():
return false
case st.lastGotPing.IsZero():
// This was an endpoint from the network map. Is it still in the network map?
return st.index == indexSentinelDeleted
default:
// Thiw was an endpoint discovered at runtime.
// This was an endpoint discovered at runtime.
return time.Since(st.lastGotPing) > sessionActiveTimeout
}
}
@ -3236,13 +3266,12 @@ func (de *discoEndpoint) sendPingsLocked(now time.Time, sendCallMeMaybe bool) {
}
derpAddr := de.derpAddr
if sentAny && sendCallMeMaybe && !derpAddr.IsZero() {
// In just a bit of a time (for goroutines above to schedule and run),
// send a message to peer via DERP informing them that we've sent
// so our firewall ports are probably open and now would be a good time
// for them to connect.
time.AfterFunc(5*time.Millisecond, func() {
de.sendDiscoMessage(derpAddr, &disco.CallMeMaybe{}, discoLog)
})
// Have our magicsock.Conn figure out its STUN endpoint (if
// it doesn't know already) and then send a CallMeMaybe
// message to our peer via DERP informing them that we've
// sent so our firewall ports are probably open and now
// would be a good time for them to connect.
go de.c.enqueueCallMeMaybe(derpAddr, de)
}
}
@ -3424,10 +3453,34 @@ func (st *endpointState) addPongReplyLocked(r pongReply) {
// DERP. The contract for use of this message is that the peer has
// already sent to us via UDP, so their stateful firewall should be
// open. Now we can Ping back and make it through.
func (de *discoEndpoint) handleCallMeMaybe() {
func (de *discoEndpoint) handleCallMeMaybe(m *disco.CallMeMaybe) {
de.mu.Lock()
defer de.mu.Unlock()
now := time.Now()
for ep := range de.isCallMeMaybeEP {
de.isCallMeMaybeEP[ep] = false // mark for deletion
}
if de.isCallMeMaybeEP == nil {
de.isCallMeMaybeEP = map[netaddr.IPPort]bool{}
}
for _, ep := range m.MyNumber {
de.isCallMeMaybeEP[ep] = true
if es, ok := de.endpointState[ep]; ok {
es.callMeMaybeTime = now
} else {
de.endpointState[ep] = &endpointState{callMeMaybeTime: now}
}
}
// Delete any prior CalllMeMaybe endpoints that weren't included
// in this message.
for ep, want := range de.isCallMeMaybeEP {
if !want {
delete(de.isCallMeMaybeEP, ep)
de.deleteEndpointLocked(ep)
}
}
// Zero out all the lastPing times to force sendPingsLocked to send new ones,
// even if it's been less than 5 seconds ago.
for _, st := range de.endpointState {

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