wgengine/netstack: replace a 1500 with a const + doc
Per post-submit code review feedback of from
@@ -133,6 +133,11 @@ type Impl struct {
const nicID = 1
const mtu = tstun.DefaultMTU
+// maxUDPPacketSize is the maximum size of a UDP packet we copy in startPacketCopy
+// when relaying UDP packets. We don't use the 'mtu' const in anticipation of
+// one day making the MTU more dynamic.
+const maxUDPPacketSize = 1500
+
// Create creates and populates a new Impl.
func Create(logf logger.Logf, tundev *tstun.Wrapper, e wgengine.Engine, mc *magicsock.Conn, dialer *tsdial.Dialer, dns *dns.Manager) (*Impl, error) {
if mc == nil {
@@ -1018,7 +1023,7 @@ func startPacketCopy(ctx context.Context, cancel context.CancelFunc, dst net.Pac
}
go func() {
defer cancel() // tear down the other direction's copy
- pkt := make([]byte, 1500)
+ pkt := make([]byte, maxUDPPacketSize)
for {
select {
case <-ctx.Done():
