all: use atomic.Pointer

Also add some missing docs.

Signed-off-by: Maisem Ali <maisem@tailscale.com>

net/dns/resolver/debug.go

@@ -24,8 +24,8 @@ func init() {
 		} else if n > 10000 {
 			n = 10000
 		}
-		fl, ok := fwdLogAtomic.Load().(*fwdLog)
-		if !ok || n != len(fl.ent) {
+		fl := fwdLogAtomic.Load()
+		if fl == nil || n != len(fl.ent) {
 			fl = &fwdLog{ent: make([]fwdLogEntry, n)}
 			fwdLogAtomic.Store(fl)
 		}
@@ -33,7 +33,7 @@ func init() {
 	}))
 }
 
-var fwdLogAtomic atomic.Value // of *fwdLog
+var fwdLogAtomic atomic.Pointer[fwdLog]
 
 type fwdLog struct {
 	mu  sync.Mutex

net/dns/resolver/forwarder.go

@@ -688,7 +688,7 @@ func (f *forwarder) forwardWithDestChan(ctx context.Context, query packet, respo
 		}
 	}
 
-	if fl, ok := fwdLogAtomic.Load().(*fwdLog); ok {
+	if fl := fwdLogAtomic.Load(); fl != nil {
 		fl.addName(string(domain))
 	}
 

net/tstun/wrap.go

@@ -126,7 +126,7 @@ type Wrapper struct {
 	eventsOther chan tun.Event
 
 	// filter atomically stores the currently active packet filter
-	filter atomic.Value // of *filter.Filter
+	filter atomic.Pointer[filter.Filter]
 	// filterFlags control the verbosity of logging packet drops/accepts.
 	filterFlags filter.RunFlags
 
@@ -477,8 +477,7 @@ func (t *Wrapper) filterOut(p *packet.Parsed) filter.Response {
 		}
 	}
 
-	filt, _ := t.filter.Load().(*filter.Filter)
-
+	filt := t.filter.Load()
 	if filt == nil {
 		return filter.Drop
 	}
@@ -606,8 +605,7 @@ func (t *Wrapper) filterIn(buf []byte) filter.Response {
 		}
 	}
 
-	filt, _ := t.filter.Load().(*filter.Filter)
-
+	filt := t.filter.Load()
 	if filt == nil {
 		return filter.Drop
 	}
@@ -698,8 +696,7 @@ func (t *Wrapper) tdevWrite(buf []byte, offset int) (int, error) {
 }
 
 func (t *Wrapper) GetFilter() *filter.Filter {
-	filt, _ := t.filter.Load().(*filter.Filter)
-	return filt
+	return t.filter.Load()
 }
 
 func (t *Wrapper) SetFilter(filt *filter.Filter) {