Init mtr

Signed-off-by: Tim Foerster <tim.foerster@hetzner.de>

icmp.go

@@ -0,0 +1,53 @@
+package main
+
+import (
+	"net"
+	"time"
+
+	"golang.org/x/net/icmp"
+	"golang.org/x/net/ipv4"
+)
+
+type ICMPReturn struct {
+	Success bool
+	Addr    string
+	Elapsed time.Duration
+}
+
+func Icmp(localAddr string, dst net.Addr, ttl, pid int, timeout time.Duration) (hop ICMPReturn, err error) {
+	hop.Success = false
+	start := time.Now()
+	c, err := icmp.ListenPacket("ip4:icmp", localAddr)
+	if err != nil {
+		return hop, err
+	}
+	defer c.Close()
+	c.IPv4PacketConn().SetTTL(ttl)
+	c.SetDeadline(time.Now().Add(timeout))
+	wm := icmp.Message{
+		Type: ipv4.ICMPTypeEcho, Code: 0,
+		Body: &icmp.Echo{
+			ID: pid, Seq: 1,
+			Data: []byte(""),
+		},
+	}
+	wb, err := wm.Marshal(nil)
+	if err != nil {
+		return hop, err
+	}
+
+	if _, err := c.WriteTo(wb, dst); err != nil {
+		return hop, err
+	}
+
+	rb := make([]byte, 1500)
+	_, peer, err := c.ReadFrom(rb)
+	if err != nil {
+		return hop, err
+	}
+	elapsed := time.Since(start)
+	hop.Elapsed = elapsed
+	hop.Addr = peer.String()
+	hop.Success = true
+	return hop, err
+}

main.go

@@ -0,0 +1,152 @@
+package main
+
+import (
+	"container/ring"
+	"fmt"
+	"net"
+	"os"
+	"sync"
+	"time"
+)
+
+var (
+	MAX_HOPS         = 64
+	RING_BUFFER_SIZE = 8
+)
+
+func main() {
+	fmt.Println("Start:", time.Now())
+	m := NewMTR("8.8.8.8")
+	m.Run()
+	m.Run()
+	m.Run()
+	m.Render()
+}
+
+type HopStatistic struct {
+	Sent       int
+	Last       ICMPReturn
+	Best       ICMPReturn
+	Worst      ICMPReturn
+	SumElapsed time.Duration
+	Lost       int
+	Packets    *ring.Ring
+}
+
+func (h *HopStatistic) Render(ttl int) {
+	failedCounter := 0
+	successCounter := 0
+	h.Packets.Do(func(f interface{}) {
+		if f == nil {
+			return
+		}
+		if !f.(ICMPReturn).Success {
+			failedCounter++
+		} else {
+			successCounter++
+		}
+	})
+	addr := "???"
+	if h.Last.Addr != "" {
+		addr = h.Last.Addr
+	}
+	avg := 0.0
+	if !(h.Sent-h.Lost == 0) {
+		avg = h.SumElapsed.Seconds() * 1000 / float64(h.Sent-h.Lost)
+	}
+	fmt.Printf("%3d:|-- %-20s  %5.1f%%  %4d  %6.1f  %6.1f  %6.1f  %6.1f\n",
+		ttl,
+		addr,
+		float32(h.Lost)/float32(h.Sent)*100.0,
+		h.Sent,
+		h.Last.Elapsed.Seconds()*1000,
+		avg,
+		h.Best.Elapsed.Seconds()*1000,
+		h.Worst.Elapsed.Seconds()*1000,
+	)
+}
+
+type MTR struct {
+	mutex     *sync.RWMutex
+	Address   string                `json:"destination"`
+	Statistic map[int]*HopStatistic `json:"statistic"`
+}
+
+func NewMTR(addr string) *MTR {
+	return &MTR{
+		Address:   addr,
+		mutex:     &sync.RWMutex{},
+		Statistic: map[int]*HopStatistic{},
+	}
+}
+
+func (m *MTR) registerStatistic(ttl int, r ICMPReturn) {
+	if m.Statistic[ttl] == nil {
+		m.Statistic[ttl] = &HopStatistic{
+			Sent:       1,
+			Last:       r,
+			Best:       r,
+			Worst:      r,
+			Lost:       0,
+			SumElapsed: r.Elapsed,
+			Packets:    ring.New(RING_BUFFER_SIZE),
+		}
+		if !r.Success {
+			m.Statistic[ttl].Lost++
+		}
+		m.Statistic[ttl].Packets.Value = r
+		return
+	}
+	s := m.Statistic[ttl]
+	s.Packets = s.Packets.Next()
+	s.Packets.Value = r
+	s.Sent++
+	s.SumElapsed = r.Elapsed + s.SumElapsed
+	if !r.Success {
+		m.Statistic[ttl].Lost++
+	}
+	s.Last = r
+	if s.Best.Elapsed > r.Elapsed {
+		s.Best = r
+	}
+	if s.Worst.Elapsed < r.Elapsed {
+		s.Worst = r
+	}
+}
+
+func (m *MTR) Render() {
+	fmt.Printf("HOP:    %-20s  %5s%%  %4s  %6s  %6s  %6s  %6s\n", "Address", "Loss", "Sent", "Last", "Avg", "Best", "Worst")
+	for i := 1; i <= len(m.Statistic); i++ {
+		m.mutex.RLock()
+		m.Statistic[i].Render(i)
+		m.mutex.RUnlock()
+	}
+}
+
+func (m *MTR) Run() {
+	ipAddr := net.IPAddr{IP: net.ParseIP(m.Address)}
+	pid := os.Getpid() & 0xffff
+	timeout := 500 * time.Millisecond
+	ttlDoubleBump := false
+
+	for ttl := 1; ttl < 64; ttl++ {
+		hopReturn, err := Icmp("0.0.0.0", &ipAddr, ttl, pid, timeout)
+		if err != nil || !hopReturn.Success {
+			if ttlDoubleBump {
+				break
+			}
+			m.mutex.Lock()
+			m.registerStatistic(ttl, hopReturn)
+			m.mutex.Unlock()
+			ttlDoubleBump = true
+			continue
+		}
+		ttlDoubleBump = false
+		m.mutex.Lock()
+		m.registerStatistic(ttl, hopReturn)
+		m.mutex.Unlock()
+		if hopReturn.Addr == m.Address {
+			break
+		}
+	}
+}