perf.go

package main

import (
	"fmt"
	"log"
	"strconv"

	"github.com/miekg/dns"
)

var records = map[string]string{
	"test.service.": "192.168.0.2",
}

func parseQuery(m *dns.Msg) {
	for _, q := range m.Question {
		switch q.Qtype {
		case dns.TypeA:
			ip := records[q.Name]
			if ip != "" {
				rr, err := dns.NewRR(fmt.Sprintf("%s A %s", q.Name, ip))
				if err == nil {
					m.Answer = append(m.Answer, rr)
				}
			}
		}
	}
}

func handleDnsRequest(w dns.ResponseWriter, r *dns.Msg) {
	m := new(dns.Msg)
	m.SetReply(r)
	m.Compress = false

	switch r.Opcode {
	case dns.OpcodeQuery:
		parseQuery(m)
	}

	w.WriteMsg(m)
}

func main() {
	// attach request handler func
	dns.HandleFunc("service.", handleDnsRequest)

	// start server
	port := 5354
	server := &dns.Server{Addr: ":" + strconv.Itoa(port), Net: "udp"}
	log.Printf("Starting at %d\n", port)
	err := server.ListenAndServe()
	defer server.Shutdown()
	if err != nil {
		log.Fatalf("Failed to start server: %s\n ", err.Error())
	}
}

test.sh

$ cat input
test.service. A

// After
$ dnsperf -s 127.0.0.1 -p 5354  -l 15 < input
DNS Performance Testing Tool
Version 2.3.4

[Status] Command line: dnsperf -s 127.0.0.1 -p 5354 -l 15
[Status] Sending queries (to 127.0.0.1)
[Status] Started at: Tue Oct 13 13:37:37 2020
[Status] Stopping after 15.000000 seconds
[Status] Testing complete (time limit)

Statistics:

  Queries sent:         1989032
  Queries completed:    1989032 (100.00%)
  Queries lost:         0 (0.00%)

  Response codes:       NOERROR 1989032 (100.00%)
  Average packet size:  request 30, response 58
  Run time (s):         15.000419
  Queries per second:   132598.429417

  Average Latency (s):  0.000648 (min 0.000021, max 0.008631)
  Latency StdDev (s):   0.000459

// Before
$ dnsperf -s 127.0.0.1 -p 5354  -l 15 < input
DNS Performance Testing Tool
Version 2.3.4

[Status] Command line: dnsperf -s 127.0.0.1 -p 5354 -l 15
[Status] Sending queries (to 127.0.0.1)
[Status] Started at: Tue Oct 13 13:38:45 2020
[Status] Stopping after 15.000000 seconds
[Status] Testing complete (time limit)

Statistics:

  Queries sent:         1917456
  Queries completed:    1917456 (100.00%)
  Queries lost:         0 (0.00%)

  Response codes:       NOERROR 1917456 (100.00%)
  Average packet size:  request 30, response 58
  Run time (s):         15.000557
  Queries per second:   127825.653407

  Average Latency (s):  0.000616 (min 0.000021, max 0.007693)
  Latency StdDev (s):   0.000442