alrm/check/ping/ping.go

661 lines
14 KiB
Go

// Package ping is an ICMP ping library seeking to emulate the unix "ping"
// command.
//
// Here is a very simple example that sends & receives 3 packets:
//
// pinger, err := ping.NewPinger("www.google.com")
// if err != nil {
// panic(err)
// }
//
// pinger.Count = 3
// pinger.Run() // blocks until finished
// stats := pinger.Statistics() // get send/receive/rtt stats
//
// Here is an example that emulates the unix ping command:
//
// pinger, err := ping.NewPinger("www.google.com")
// if err != nil {
// fmt.Printf("ERROR: %s\n", err.Error())
// return
// }
//
// pinger.OnRecv = func(pkt *ping.Packet) {
// fmt.Printf("%d bytes from %s: icmp_seq=%d time=%v\n",
// pkt.Nbytes, pkt.IPAddr, pkt.Seq, pkt.Rtt)
// }
// pinger.OnFinish = func(stats *ping.Statistics) {
// fmt.Printf("\n--- %s ping statistics ---\n", stats.Addr)
// fmt.Printf("%d packets transmitted, %d packets received, %v%% packet loss\n",
// stats.PacketsSent, stats.PacketsRecv, stats.PacketLoss)
// fmt.Printf("round-trip min/avg/max/stddev = %v/%v/%v/%v\n",
// stats.MinRtt, stats.AvgRtt, stats.MaxRtt, stats.StdDevRtt)
// }
//
// fmt.Printf("PING %s (%s):\n", pinger.Addr(), pinger.IPAddr())
// pinger.Run()
//
// It sends ICMP packet(s) and waits for a response. If it receives a response,
// it calls the "receive" callback. When it's finished, it calls the "finish"
// callback.
//
// For a full ping example, see "cmd/ping/ping.go".
//
package ping
import (
"bytes"
"encoding/binary"
"errors"
"fmt"
"math"
"math/rand"
"net"
"runtime"
"sync"
"syscall"
"time"
"golang.org/x/net/icmp"
"golang.org/x/net/ipv4"
"golang.org/x/net/ipv6"
)
const (
timeSliceLength = 8
trackerLength = 8
protocolICMP = 1
protocolIPv6ICMP = 58
)
var (
ipv4Proto = map[string]string{"icmp": "ip4:icmp", "udp": "udp4"}
ipv6Proto = map[string]string{"icmp": "ip6:ipv6-icmp", "udp": "udp6"}
)
// New returns a new Pinger struct pointer.
func New(addr string) *Pinger {
r := rand.New(rand.NewSource(time.Now().UnixNano()))
return &Pinger{
Count: -1,
Interval: time.Second,
RecordRtts: true,
Size: timeSliceLength,
Timeout: time.Second * 100000,
Tracker: r.Int63n(math.MaxInt64),
addr: addr,
done: make(chan bool),
id: r.Intn(math.MaxInt16),
ipaddr: nil,
ipv4: false,
network: "ip",
protocol: "udp",
}
}
// NewPinger returns a new Pinger and resolves the address.
func NewPinger(addr string) (*Pinger, error) {
p := New(addr)
return p, p.Resolve()
}
// Pinger represents a packet sender/receiver.
type Pinger struct {
// Interval is the wait time between each packet send. Default is 1s.
Interval time.Duration
// Timeout specifies a timeout before ping exits, regardless of how many
// packets have been received.
Timeout time.Duration
// Count tells pinger to stop after sending (and receiving) Count echo
// packets. If this option is not specified, pinger will operate until
// interrupted.
Count int
// Debug runs in debug mode
Debug bool
// Number of packets sent
PacketsSent int
// Number of packets received
PacketsRecv int
// If true, keep a record of rtts of all received packets.
// Set to false to avoid memory bloat for long running pings.
RecordRtts bool
// rtts is all of the Rtts
rtts []time.Duration
// OnSend is called when Pinger sends a packet
OnSend func(*Packet)
// OnRecv is called when Pinger receives and processes a packet
OnRecv func(*Packet)
// OnFinish is called when Pinger exits
OnFinish func(*Statistics)
// Size of packet being sent
Size int
// Tracker: Used to uniquely identify packet when non-priviledged
Tracker int64
// Source is the source IP address
Source string
// stop chan bool
done chan bool
ipaddr *net.IPAddr
addr string
ipv4 bool
id int
sequence int
// network is one of "ip", "ip4", or "ip6".
network string
// protocol is "icmp" or "udp".
protocol string
}
type packet struct {
bytes []byte
nbytes int
ttl int
}
// Packet represents a received and processed ICMP echo packet.
type Packet struct {
// Rtt is the round-trip time it took to ping.
Rtt time.Duration
// IPAddr is the address of the host being pinged.
IPAddr *net.IPAddr
// Addr is the string address of the host being pinged.
Addr string
// NBytes is the number of bytes in the message.
Nbytes int
// Seq is the ICMP sequence number.
Seq int
// TTL is the Time To Live on the packet.
Ttl int
}
// Statistics represent the stats of a currently running or finished
// pinger operation.
type Statistics struct {
// PacketsRecv is the number of packets received.
PacketsRecv int
// PacketsSent is the number of packets sent.
PacketsSent int
// PacketLoss is the percentage of packets lost.
PacketLoss float64
// IPAddr is the address of the host being pinged.
IPAddr *net.IPAddr
// Addr is the string address of the host being pinged.
Addr string
// Rtts is all of the round-trip times sent via this pinger.
Rtts []time.Duration
// MinRtt is the minimum round-trip time sent via this pinger.
MinRtt time.Duration
// MaxRtt is the maximum round-trip time sent via this pinger.
MaxRtt time.Duration
// AvgRtt is the average round-trip time sent via this pinger.
AvgRtt time.Duration
// StdDevRtt is the standard deviation of the round-trip times sent via
// this pinger.
StdDevRtt time.Duration
}
// SetIPAddr sets the ip address of the target host.
func (p *Pinger) SetIPAddr(ipaddr *net.IPAddr) {
p.ipv4 = isIPv4(ipaddr.IP)
p.ipaddr = ipaddr
p.addr = ipaddr.String()
}
// IPAddr returns the ip address of the target host.
func (p *Pinger) IPAddr() *net.IPAddr {
return p.ipaddr
}
// Resolve does the DNS lookup for the Pinger address and sets IP protocol.
func (p *Pinger) Resolve() error {
if len(p.addr) == 0 {
return errors.New("addr cannot be empty")
}
ipaddr, err := net.ResolveIPAddr(p.network, p.addr)
if err != nil {
return err
}
p.ipv4 = isIPv4(ipaddr.IP)
p.ipaddr = ipaddr
return nil
}
// SetAddr resolves and sets the ip address of the target host, addr can be a
// DNS name like "www.google.com" or IP like "127.0.0.1".
func (p *Pinger) SetAddr(addr string) error {
oldAddr := p.addr
p.addr = addr
err := p.Resolve()
if err != nil {
p.addr = oldAddr
return err
}
return nil
}
// Addr returns the string ip address of the target host.
func (p *Pinger) Addr() string {
return p.addr
}
// SetNetwork allows configuration of DNS resolution.
// * "ip" will automatically select IPv4 or IPv6.
// * "ip4" will select IPv4.
// * "ip6" will select IPv6.
func (p *Pinger) SetNetwork(n string) {
switch n {
case "ip4":
p.network = "ip4"
case "ip6":
p.network = "ip6"
default:
p.network = "ip"
}
}
// SetPrivileged sets the type of ping pinger will send.
// false means pinger will send an "unprivileged" UDP ping.
// true means pinger will send a "privileged" raw ICMP ping.
// NOTE: setting to true requires that it be run with super-user privileges.
func (p *Pinger) SetPrivileged(privileged bool) {
if privileged {
p.protocol = "icmp"
} else {
p.protocol = "udp"
}
}
// Privileged returns whether pinger is running in privileged mode.
func (p *Pinger) Privileged() bool {
return p.protocol == "icmp"
}
// Run runs the pinger. This is a blocking function that will exit when it's
// done. If Count or Interval are not specified, it will run continuously until
// it is interrupted.
func (p *Pinger) Run() error {
var conn *icmp.PacketConn
var err error
if p.ipaddr == nil {
err = p.Resolve()
}
if err != nil {
return err
}
if p.ipv4 {
if conn, err = p.listen(ipv4Proto[p.protocol]); err != nil {
return err
}
if err = conn.IPv4PacketConn().SetControlMessage(ipv4.FlagTTL, true); runtime.GOOS != "windows" && err != nil {
return err
}
} else {
if conn, err = p.listen(ipv6Proto[p.protocol]); err != nil {
return err
}
if err = conn.IPv6PacketConn().SetControlMessage(ipv6.FlagHopLimit, true); runtime.GOOS != "windows" && err != nil {
return err
}
}
defer conn.Close()
defer p.finish()
var wg sync.WaitGroup
recv := make(chan *packet, 5)
defer close(recv)
wg.Add(1)
//nolint:errcheck
go p.recvICMP(conn, recv, &wg)
err = p.sendICMP(conn)
if err != nil {
return err
}
timeout := time.NewTicker(p.Timeout)
defer timeout.Stop()
interval := time.NewTicker(p.Interval)
defer interval.Stop()
for {
select {
case <-p.done:
wg.Wait()
return nil
case <-timeout.C:
close(p.done)
wg.Wait()
return nil
case <-interval.C:
if p.Count > 0 && p.PacketsSent >= p.Count {
continue
}
err = p.sendICMP(conn)
if err != nil {
// FIXME: this logs as FATAL but continues
fmt.Println("FATAL: ", err.Error())
}
case r := <-recv:
err := p.processPacket(r)
if err != nil {
// FIXME: this logs as FATAL but continues
fmt.Println("FATAL: ", err.Error())
}
}
if p.Count > 0 && p.PacketsRecv >= p.Count {
close(p.done)
wg.Wait()
return nil
}
}
}
func (p *Pinger) Stop() {
close(p.done)
}
func (p *Pinger) finish() {
handler := p.OnFinish
if handler != nil {
s := p.Statistics()
handler(s)
}
}
// Statistics returns the statistics of the pinger. This can be run while the
// pinger is running or after it is finished. OnFinish calls this function to
// get it's finished statistics.
func (p *Pinger) Statistics() *Statistics {
loss := float64(p.PacketsSent-p.PacketsRecv) / float64(p.PacketsSent) * 100
var min, max, total time.Duration
if len(p.rtts) > 0 {
min = p.rtts[0]
max = p.rtts[0]
}
for _, rtt := range p.rtts {
if rtt < min {
min = rtt
}
if rtt > max {
max = rtt
}
total += rtt
}
s := Statistics{
PacketsSent: p.PacketsSent,
PacketsRecv: p.PacketsRecv,
PacketLoss: loss,
Rtts: p.rtts,
Addr: p.addr,
IPAddr: p.ipaddr,
MaxRtt: max,
MinRtt: min,
}
if len(p.rtts) > 0 {
s.AvgRtt = total / time.Duration(len(p.rtts))
var sumsquares time.Duration
for _, rtt := range p.rtts {
sumsquares += (rtt - s.AvgRtt) * (rtt - s.AvgRtt)
}
s.StdDevRtt = time.Duration(math.Sqrt(
float64(sumsquares / time.Duration(len(p.rtts)))))
}
return &s
}
func (p *Pinger) recvICMP(
conn *icmp.PacketConn,
recv chan<- *packet,
wg *sync.WaitGroup,
) error {
defer wg.Done()
for {
select {
case <-p.done:
return nil
default:
bytes := make([]byte, 512)
if err := conn.SetReadDeadline(time.Now().Add(time.Millisecond * 100)); err != nil {
return err
}
var n, ttl int
var err error
if p.ipv4 {
var cm *ipv4.ControlMessage
n, cm, _, err = conn.IPv4PacketConn().ReadFrom(bytes)
if cm != nil {
ttl = cm.TTL
}
} else {
var cm *ipv6.ControlMessage
n, cm, _, err = conn.IPv6PacketConn().ReadFrom(bytes)
if cm != nil {
ttl = cm.HopLimit
}
}
if err != nil {
if neterr, ok := err.(*net.OpError); ok {
if neterr.Timeout() {
// Read timeout
continue
} else {
close(p.done)
return err
}
}
}
select {
case <-p.done:
return nil
case recv <- &packet{bytes: bytes, nbytes: n, ttl: ttl}:
}
}
}
}
func (p *Pinger) processPacket(recv *packet) error {
receivedAt := time.Now()
var proto int
if p.ipv4 {
proto = protocolICMP
} else {
proto = protocolIPv6ICMP
}
var m *icmp.Message
var err error
if m, err = icmp.ParseMessage(proto, recv.bytes); err != nil {
return fmt.Errorf("error parsing icmp message: %s", err.Error())
}
if m.Type != ipv4.ICMPTypeEchoReply && m.Type != ipv6.ICMPTypeEchoReply {
// Not an echo reply, ignore it
return nil
}
outPkt := &Packet{
Nbytes: recv.nbytes,
IPAddr: p.ipaddr,
Addr: p.addr,
Ttl: recv.ttl,
}
switch pkt := m.Body.(type) {
case *icmp.Echo:
// If we are priviledged, we can match icmp.ID
if p.protocol == "icmp" {
// Check if reply from same ID
if pkt.ID != p.id {
return nil
}
}
if len(pkt.Data) < timeSliceLength+trackerLength {
return fmt.Errorf("insufficient data received; got: %d %v",
len(pkt.Data), pkt.Data)
}
tracker := bytesToInt(pkt.Data[timeSliceLength:])
timestamp := bytesToTime(pkt.Data[:timeSliceLength])
if tracker != p.Tracker {
return nil
}
outPkt.Rtt = receivedAt.Sub(timestamp)
outPkt.Seq = pkt.Seq
p.PacketsRecv++
default:
// Very bad, not sure how this can happen
return fmt.Errorf("invalid ICMP echo reply; type: '%T', '%v'", pkt, pkt)
}
if p.RecordRtts {
p.rtts = append(p.rtts, outPkt.Rtt)
}
handler := p.OnRecv
if handler != nil {
handler(outPkt)
}
return nil
}
func (p *Pinger) sendICMP(conn *icmp.PacketConn) error {
var typ icmp.Type
if p.ipv4 {
typ = ipv4.ICMPTypeEcho
} else {
typ = ipv6.ICMPTypeEchoRequest
}
var dst net.Addr = p.ipaddr
if p.protocol == "udp" {
dst = &net.UDPAddr{IP: p.ipaddr.IP, Zone: p.ipaddr.Zone}
}
t := append(timeToBytes(time.Now()), intToBytes(p.Tracker)...)
if remainSize := p.Size - timeSliceLength - trackerLength; remainSize > 0 {
t = append(t, bytes.Repeat([]byte{1}, remainSize)...)
}
body := &icmp.Echo{
ID: p.id,
Seq: p.sequence,
Data: t,
}
msg := &icmp.Message{
Type: typ,
Code: 0,
Body: body,
}
msgBytes, err := msg.Marshal(nil)
if err != nil {
return err
}
for {
if _, err := conn.WriteTo(msgBytes, dst); err != nil {
if neterr, ok := err.(*net.OpError); ok {
if neterr.Err == syscall.ENOBUFS {
continue
}
}
}
handler := p.OnSend
if handler != nil {
outPkt := &Packet{
Nbytes: len(msgBytes),
IPAddr: p.ipaddr,
Addr: p.addr,
Seq: p.sequence,
}
handler(outPkt)
}
p.PacketsSent++
p.sequence++
break
}
return nil
}
func (p *Pinger) listen(netProto string) (*icmp.PacketConn, error) {
conn, err := icmp.ListenPacket(netProto, p.Source)
if err != nil {
close(p.done)
return nil, err
}
return conn, nil
}
func bytesToTime(b []byte) time.Time {
var nsec int64
for i := uint8(0); i < 8; i++ {
nsec += int64(b[i]) << ((7 - i) * 8)
}
return time.Unix(nsec/1000000000, nsec%1000000000)
}
func isIPv4(ip net.IP) bool {
return len(ip.To4()) == net.IPv4len
}
func timeToBytes(t time.Time) []byte {
nsec := t.UnixNano()
b := make([]byte, 8)
for i := uint8(0); i < 8; i++ {
b[i] = byte((nsec >> ((7 - i) * 8)) & 0xff)
}
return b
}
func bytesToInt(b []byte) int64 {
return int64(binary.BigEndian.Uint64(b))
}
func intToBytes(tracker int64) []byte {
b := make([]byte, 8)
binary.BigEndian.PutUint64(b, uint64(tracker))
return b
}