net/tunstats: add Counts.Add (#5848)

The Counts.Add method merges two Counts together.

Signed-off-by: Joe Tsai <joetsai@digital-static.net>

net/tunstats/stats.go

@@ -29,6 +29,15 @@ type Counts struct {
 	RxBytes   uint64 `json:"rxBytes,omitempty"`
 }
 
+// Add adds the counts from both c1 and c2.
+func (c1 Counts) Add(c2 Counts) Counts {
+	c1.TxPackets += c2.TxPackets
+	c1.TxBytes += c2.TxBytes
+	c1.RxPackets += c2.RxPackets
+	c1.RxBytes += c2.RxBytes
+	return c1
+}
+
 // UpdateTx updates the counters for a transmitted IP packet
 // The source and destination of the packet directly correspond with
 // the source and destination in flowtrack.Tuple.

net/tunstats/stats_test.go

@@ -111,13 +111,8 @@ func TestConcurrent(t *testing.T) {
 
 func mergeMaps(dst map[flowtrack.Tuple]Counts, srcs ...map[flowtrack.Tuple]Counts) {
 	for _, src := range srcs {
-		for tuple, cntsSrc := range src {
-			cntsDst := dst[tuple]
-			cntsDst.TxPackets += cntsSrc.TxPackets
-			cntsDst.TxBytes += cntsSrc.TxBytes
-			cntsDst.RxPackets += cntsSrc.RxPackets
-			cntsDst.RxBytes += cntsSrc.RxBytes
-			dst[tuple] = cntsDst
+		for tuple, cnts := range src {
+			dst[tuple] = dst[tuple].Add(cnts)
 		}
 	}
 }