Don't do unnecessary clock skew check in IPAM

ipam/allocator.go

@@ -469,7 +469,7 @@ func (alloc *Allocator) OnGossipBroadcast(sender mesh.PeerName, msg []byte) (mes
 
 type gossipState struct {
 	// We send a timstamp along with the information to be
-	// gossipped in order to detect skewed clocks
+	// gossipped for backwards-compatibility (previously to detect skewed clocks)
 	Now       int64
 	Nicknames map[mesh.PeerName]string
 
@@ -673,11 +673,6 @@ func (alloc *Allocator) update(sender mesh.PeerName, msg []byte) error {
 		return err
 	}
 
-	deltat := time.Unix(data.Now, 0).Sub(alloc.now())
-	if deltat > time.Hour || -deltat > time.Hour {
-		return fmt.Errorf("clock skew of %v detected, ignoring update", deltat)
-	}
-
 	// Merge nicknames
 	for peer, nickname := range data.Nicknames {
 		alloc.nicknames[peer] = nickname

ipam/allocator_test.go

@@ -577,18 +577,6 @@ func TestAllocatorFuzz(t *testing.T) {
 	})
 }
 
-func TestGossipSkew(t *testing.T) {
-	alloc1, _ := makeAllocatorWithMockGossip(t, "01:00:00:01:00:00", "10.0.1.0/22", 2)
-	defer alloc1.Stop()
-	alloc2, _ := makeAllocatorWithMockGossip(t, "02:00:00:02:00:00", "10.0.1.0/22", 2)
-	alloc2.now = func() time.Time { return time.Now().Add(time.Hour * 2) }
-	defer alloc2.Stop()
-
-	if _, err := alloc1.OnGossipBroadcast(alloc2.ourName, alloc2.Encode()); err == nil {
-		t.Fail()
-	}
-}
-
 func TestSpaceRequest(t *testing.T) {
 	const (
 		container1 = "cont-1"