[ AGNTLOG-700 ] Honor bind_host on UDP log listeners

pkg/logs/launchers/listener/udp.go

@@ -8,6 +8,7 @@ package listener
 import (
 	"fmt"
 	"net"
+	"strconv"
 
 	"github.com/DataDog/datadog-agent/pkg/util/log"
 
@@ -110,7 +111,8 @@ func (l *UDPListener) resetTailer() {
 // newUDPConnection returns a new UDP connection,
 // returns an error if the creation failed.
 func (l *UDPListener) newUDPConnection() (*net.UDPConn, error) {
-	udpAddr, err := net.ResolveUDPAddr("udp", fmt.Sprintf(":%d", l.source.Config.Port))
+	bindAddr := net.JoinHostPort(l.source.Config.BindHost, strconv.Itoa(l.source.Config.Port))
+	udpAddr, err := net.ResolveUDPAddr("udp", bindAddr)
 	if err != nil {
 		return nil, err
 	}

pkg/logs/launchers/listener/udp_test.go

@@ -8,6 +8,7 @@ package listener
 import (
 	"fmt"
 	"net"
+	"strings"
 	"testing"
 	"time"
 
@@ -47,6 +48,31 @@ func TestUDPShouldReceiveMessage(t *testing.T) {
 	listener.Stop()
 }
 
+func TestUDPBindHost(t *testing.T) {
+	pp := mock.NewMockProvider()
+	msgChan := pp.NextPipelineChan()
+	listener, err := NewUDPListener(pp, sources.NewLogSource("", &config.LogsConfig{
+		Port:     udpTestPort,
+		BindHost: "127.0.0.1",
+	}), 9000)
+	require.NoError(t, err)
+	listener.Start()
+	require.NotNil(t, listener.Conn)
+
+	addr := listener.Conn.LocalAddr().String()
+	assert.True(t, strings.HasPrefix(addr, "127.0.0.1:"), "expected 127.0.0.1 bind, got %s", addr)
+
+	conn, err := net.Dial("udp", addr)
+	require.NoError(t, err)
+	defer conn.Close()
+
+	fmt.Fprint(conn, "bound msg\n")
+	msg := <-msgChan
+	assert.Equal(t, "bound msg", string(msg.GetContent()))
+
+	listener.Stop()
+}
+
 func TestUDPShouldStopWhenNotStarted(t *testing.T) {
 	pp := mock.NewMockProvider()
 	listener, err := NewUDPListener(pp, sources.NewLogSource("", &config.LogsConfig{Port: udpTestPort}), 9000)

releasenotes/notes/logs-udp-listener-bind-host-fc9b109c334a0be6.yaml

@@ -0,0 +1,4 @@
+---
+fixes:
+  - |
+    Add new ``bind_host`` configuration option to TCP and UDP log listeners.