Add AggregateCounter

util/clientmetric/clientmetric.go

@@ -9,6 +9,7 @@ import (
 	"bytes"
 	"encoding/binary"
 	"encoding/hex"
+	"expvar"
 	"fmt"
 	"io"
 	"sort"
@@ -223,6 +224,33 @@ func NewGaugeFunc(name string, f func() int64) *Metric {
 	return m
 }
 
+type AggregateCounter struct {
+	mu       sync.RWMutex
+	counters []*expvar.Int
+}
+
+func (c *AggregateCounter) Value() int64 {
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+	var sum int64
+	for _, c := range c.counters {
+		sum += c.Value()
+	}
+	return sum
+}
+
+func (c *AggregateCounter) Add(counter *expvar.Int) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	c.counters = append(c.counters, counter)
+}
+
+func NewAggregateCounter(name string) *AggregateCounter {
+	c := &AggregateCounter{}
+	NewGaugeFunc(name, c.Value)
+	return c
+}
+
 // WritePrometheusExpositionFormat writes all client metrics to w in
 // the Prometheus text-based exposition format.
 //

wgengine/magicsock/derp.go

@@ -690,7 +690,6 @@ func (c *connBind) receiveDERP(buffs [][]byte, sizes []int, eps []conn.Endpoint)
 			// No data read occurred. Wait for another packet.
 			continue
 		}
-		metricRecvDataPacketsDERP.Add(1)
 		c.metrics.inboundPacketsDERPTotal.Add(1)
 		c.metrics.inboundBytesDERPTotal.Add(int64(n))
 		sizes[0] = n

wgengine/magicsock/magicsock.go

@@ -623,6 +623,10 @@ func registerMetrics(reg *usermetric.Registry) *metrics {
 		outboundBytesDERPTotal: &expvar.Int{},
 	}
 
+	metricRecvDataPacketsDERP.Add(m.inboundPacketsDERPTotal)
+	metricSendUDP.Add(m.outboundPacketsIPv4Total)
+	metricSendUDP.Add(m.outboundPacketsIPv6Total)
+
 	inboundPacketsTotal.Set(pathDirectV4, m.inboundPacketsIPv4Total)
 	inboundPacketsTotal.Set(pathDirectV6, m.inboundPacketsIPv6Total)
 	inboundPacketsTotal.Set(pathDERP, m.inboundPacketsDERPTotal)
@@ -1262,8 +1266,6 @@ func (c *Conn) sendUDP(ipp netip.AddrPort, b []byte) (sent bool, err error) {
 		_ = c.maybeRebindOnError(runtime.GOOS, err)
 	} else {
 		if sent {
-			metricSendUDP.Add(1)
-
 			switch {
 			case ipp.Addr().Is4():
 				c.metrics.outboundPacketsIPv4Total.Add(1)
@@ -3075,7 +3077,7 @@ var (
 	metricSendDERPErrorChan   = clientmetric.NewCounter("magicsock_send_derp_error_chan")
 	metricSendDERPErrorClosed = clientmetric.NewCounter("magicsock_send_derp_error_closed")
 	metricSendDERPErrorQueue  = clientmetric.NewCounter("magicsock_send_derp_error_queue")
-	metricSendUDP             = clientmetric.NewCounter("magicsock_send_udp")
+	metricSendUDP             = clientmetric.NewAggregateCounter("magicsock_send_udp")
 	metricSendUDPError        = clientmetric.NewCounter("magicsock_send_udp_error")
 	metricSendDERP            = clientmetric.NewCounter("magicsock_send_derp")
 	metricSendDERPError       = clientmetric.NewCounter("magicsock_send_derp_error")
@@ -3083,7 +3085,7 @@ var (
 	// Data packets (non-disco)
 	metricSendData            = clientmetric.NewCounter("magicsock_send_data")
 	metricSendDataNetworkDown = clientmetric.NewCounter("magicsock_send_data_network_down")
-	metricRecvDataPacketsDERP = clientmetric.NewCounter("magicsock_recv_data_derp")
+	metricRecvDataPacketsDERP = clientmetric.NewAggregateCounter("magicsock_recv_data_derp")
 	metricRecvDataPacketsIPv4 = clientmetric.NewCounter("magicsock_recv_data_ipv4")
 	metricRecvDataPacketsIPv6 = clientmetric.NewCounter("magicsock_recv_data_ipv6")
 

wgengine/magicsock/magicsock_test.go

@@ -1264,6 +1264,8 @@ func assertConnStatsAndUserMetricsEqual(t *testing.T, ms *magicStack) {
 	assertEqual(t, "derp packets outbound", physDERPTxPackets, metricDERPTxPackets)
 	assertEqual(t, "ipv4 packets inbound", physIPv4RxPackets, metricIPv4RxPackets)
 	assertEqual(t, "ipv4 packets outbound", physIPv4TxPackets, metricIPv4TxPackets)
+
+	assertEqual(t, "outbound udp packets - compare with clientmetric", metricSendUDP.Value(), metricIPv4TxPackets*2)
 }
 
 func assertEqual(t *testing.T, name string, a, b any) {