all: fix potential undefined behavior in timer reset

common/countdown/countdown.go

@@ -89,7 +89,10 @@ func (t *CountdownTimer) startTimer(i interface{}, currentRound, highestRound ty
 			currentRound = info.currentRound
 			highestRound = info.highestRound
 			if !timer.Stop() {
-				<-timer.C
+				select {
+				case <-timer.C: // try to drain the channel
+				default:
+				}
 			}
 			timer.Reset(t.durationHelper.GetTimeoutDuration(currentRound, highestRound))
 		}

eth/filters/api.go

@@ -432,7 +432,10 @@ func (api *FilterAPI) GetFilterChanges(id rpc.ID) (interface{}, error) {
 		if !f.deadline.Stop() {
 			// timer expired but filter is not yet removed in timeout loop
 			// receive timer value and reset timer
-			<-f.deadline.C
+			select {
+			case <-f.deadline.C: // try to drain the channel
+			default:
+			}
 		}
 		f.deadline.Reset(api.timeout)
 

p2p/nat/nat.go

@@ -26,7 +26,7 @@ import (
 	"time"
 
 	"github.com/XinFinOrg/XDPoSChain/log"
-	"github.com/jackpal/go-nat-pmp"
+	natpmp "github.com/jackpal/go-nat-pmp"
 )
 
 // An implementation of nat.Interface can map local ports to ports
@@ -53,12 +53,12 @@ type Interface interface {
 // The following formats are currently accepted.
 // Note that mechanism names are not case-sensitive.
 //
-//     "" or "none"         return nil
-//     "extip:77.12.33.4"   will assume the local machine is reachable on the given IP
-//     "any"                uses the first auto-detected mechanism
-//     "upnp"               uses the Universal Plug and Play protocol
-//     "pmp"                uses NAT-PMP with an auto-detected gateway address
-//     "pmp:192.168.0.1"    uses NAT-PMP with the given gateway address
+//	"" or "none"         return nil
+//	"extip:77.12.33.4"   will assume the local machine is reachable on the given IP
+//	"any"                uses the first auto-detected mechanism
+//	"upnp"               uses the Universal Plug and Play protocol
+//	"pmp"                uses NAT-PMP with an auto-detected gateway address
+//	"pmp:192.168.0.1"    uses NAT-PMP with the given gateway address
 func Parse(spec string) (Interface, error) {
 	var (
 		parts = strings.SplitN(spec, ":", 2)