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wgengine/magicsock: start tracking nearest DERP node

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This commit is contained in:
Brad Fitzpatrick
2020-03-03 17:46:03 -08:00
parent dbc99dc0d2
commit 724c37fb41
3 changed files with 41 additions and 14 deletions
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30
wgengine/magicsock/magicsock.go
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@@ -71,6 +71,7 @@ type Conn struct {
derpMu sync.Mutex
privateKey key.Private
myDerp int // nearest DERP server; 0 means none/unknown
derpConn map[int]*derphttp.Client // magic derp port (see derpmap.go) to its client
derpCancel map[int]context.CancelFunc // to close derp goroutines
derpWriteCh map[int]chan<- derpWriteRequest
@@ -203,25 +204,40 @@ func (c *Conn) epUpdate(ctx context.Context) {
go func() {
defer close(lastDone)
endpoints, err := c.determineEndpoints(epCtx)
nearestDerp, endpoints, err := c.determineEndpoints(epCtx)
if err != nil {
c.logf("magicsock.Conn: endpoint update failed: %v", err)
// TODO(crawshaw): are there any conditions under which
// we should trigger a retry based on the error here?
return
}
if stringsEqual(endpoints, lastEndpoints) {
derpChanged := c.setNearestDerp(nearestDerp)
if stringsEqual(endpoints, lastEndpoints) && !derpChanged {
return
}
lastEndpoints = endpoints
// TODO(bradfiz): get nearestDerp back to ipn for a HostInfo update
c.epFunc(endpoints)
}()
}
}
func (c *Conn) setNearestDerp(derpNum int) (changed bool) {
c.derpMu.Lock()
defer c.derpMu.Unlock()
changed = c.myDerp != derpNum
if changed && derpNum != 0 {
// On change, start connecting to it:
go c.derpWriteChanOfAddr(&net.UDPAddr{IP: derpMagicIP, Port: derpNum})
}
c.myDerp = derpNum
return changed
}
// determineEndpoints returns the machine's endpoint addresses. It
// does a STUN lookup to determine its public address.
func (c *Conn) determineEndpoints(ctx context.Context) ([]string, error) {
func (c *Conn) determineEndpoints(ctx context.Context) (nearestDerp int, ipPorts []string, err error) {
nearestDerp = derpNYC // for now
var (
alreadyMu sync.Mutex
already = make(map[string]bool) // endpoint -> true
@@ -249,7 +265,7 @@ func (c *Conn) determineEndpoints(ctx context.Context) ([]string, error) {
c.stunReceiveFunc.Store(s.Receive)
if err := s.Run(ctx); err != nil {
return nil, err
return 0, nil, err
}
c.ignoreSTUNPackets()
@@ -257,7 +273,7 @@ func (c *Conn) determineEndpoints(ctx context.Context) ([]string, error) {
if localAddr := c.pconn.LocalAddr(); localAddr.IP.IsUnspecified() {
ips, loopback, err := interfaces.LocalAddresses()
if err != nil {
return nil, err
return 0, nil, err
}
reason := "localAddresses"
if len(ips) == 0 {
@@ -287,7 +303,7 @@ func (c *Conn) determineEndpoints(ctx context.Context) ([]string, error) {
// The STUN address(es) are always first so that legacy wireguard
// can use eps[0] as its only known endpoint address (although that's
// obviously non-ideal).
return eps, nil
return nearestDerp, eps, nil
}
func stringsEqual(x, y []string) bool {
@@ -496,7 +512,7 @@ func (c *Conn) derpWriteChanOfAddr(addr *net.UDPAddr) chan<- derpWriteRequest {
}
ctx, cancel := context.WithCancel(context.Background())
// TODO: close derp channels (if addr.Port != myDerp) on inactivity timer
bidiCh := make(chan derpWriteRequest, bufferedDerpWritesBeforeDrop)
ch = bidiCh
c.derpConn[addr.Port] = dc