/
udp.go
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/
udp.go
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// Copyright Istio Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package endpoint
import (
"fmt"
"net"
"net/http"
"os"
"strconv"
"strings"
"github.com/google/uuid"
"istio.io/istio/pkg/test/echo"
"istio.io/istio/pkg/test/util/retry"
)
var _ Instance = &udpInstance{}
type udpInstance struct {
Config
l net.PacketConn
}
func newUDP(config Config) Instance {
return &udpInstance{
Config: config,
}
}
func (s *udpInstance) GetConfig() Config {
return s.Config
}
func (s *udpInstance) Start(onReady OnReadyFunc) error {
var listener net.PacketConn
var port int
var err error
if s.Port.TLS {
return fmt.Errorf("TLS not supported for UDP")
}
// Listen on the given port and update the port if it changed from what was passed in.
listener, port, err = listenUDPAddress(s.ListenerIP, s.Port.Port)
// Store the actual listening port back to the argument.
s.Port.Port = port
if err != nil {
return err
}
s.l = listener
epLog.Infof("Listening UDP on %v\n", port)
// Start serving UDP traffic.
go func() {
buf := make([]byte, 2048)
for {
_, remote, err := listener.ReadFrom(buf)
if err != nil {
epLog.Warn("UDP read failed: " + err.Error())
return
}
id := uuid.New()
epLog.WithLabels("remote", remote, "id", id).Infof("UDP Request")
responseFields := s.getResponseFields(remote)
if _, err := listener.WriteTo([]byte(responseFields), remote); err != nil {
epLog.WithLabels("id", id).Warnf("UDP failed writing echo response: %v", err)
}
}
}()
// Notify the WaitGroup once the port has transitioned to ready.
go s.awaitReady(onReady, listener.LocalAddr().String())
return nil
}
func (s *udpInstance) getResponseFields(conn net.Addr) string {
ip, _, _ := net.SplitHostPort(conn.String())
// Write non-request fields specific to the instance
out := &strings.Builder{}
echo.StatusCodeField.Write(out, strconv.Itoa(http.StatusOK))
echo.ClusterField.WriteNonEmpty(out, s.Cluster)
echo.IstioVersionField.WriteNonEmpty(out, s.IstioVersion)
echo.NamespaceField.WriteNonEmpty(out, s.Namespace)
echo.ServiceVersionField.Write(out, s.Version)
echo.ServicePortField.Write(out, strconv.Itoa(s.Port.Port))
echo.IPField.Write(out, ip)
echo.ProtocolField.Write(out, "TCP")
if hostname, err := os.Hostname(); err == nil {
echo.HostnameField.Write(out, hostname)
}
return out.String()
}
func (s *udpInstance) Close() error {
if s.l != nil {
_ = s.l.Close()
}
return nil
}
func (s *udpInstance) awaitReady(onReady OnReadyFunc, address string) {
defer onReady()
err := retry.UntilSuccess(func() error {
conn, err := net.Dial("udp", address)
if err != nil {
return err
}
defer func() { _ = conn.Close() }()
// Server is up now, we're ready.
return nil
}, retry.Timeout(readyTimeout), retry.Delay(readyInterval))
if err != nil {
epLog.Errorf("readiness failed for endpoint %s: %v", address, err)
} else {
epLog.Infof("ready for UDP endpoint %s", address)
}
}