109 lines
1.9 KiB
Go
109 lines
1.9 KiB
Go
package scan
|
|
|
|
import (
|
|
"fmt"
|
|
"net"
|
|
"sync/atomic"
|
|
"time"
|
|
|
|
"golang.org/x/net/icmp"
|
|
"golang.org/x/net/ipv4"
|
|
)
|
|
|
|
type Pinger struct {
|
|
conn *icmp.PacketConn
|
|
seq atomic.Uint32
|
|
}
|
|
|
|
func NewPinger() (*Pinger, error) {
|
|
conn, err := icmp.ListenPacket("udp4", "0.0.0.0")
|
|
if err != nil {
|
|
return nil, fmt.Errorf("icmp listen: %w", err)
|
|
}
|
|
return &Pinger{conn: conn}, nil
|
|
}
|
|
|
|
func (p *Pinger) Close() {
|
|
if p.conn != nil {
|
|
p.conn.Close()
|
|
}
|
|
}
|
|
|
|
func (p *Pinger) Ping(ip string, timeout time.Duration) bool {
|
|
dst, err := net.ResolveIPAddr("ip4", ip)
|
|
if err != nil {
|
|
return false
|
|
}
|
|
|
|
var target net.Addr
|
|
switch p.conn.LocalAddr().(type) {
|
|
case *net.UDPAddr:
|
|
target = &net.UDPAddr{IP: dst.IP}
|
|
case *net.IPAddr:
|
|
target = &net.IPAddr{IP: dst.IP}
|
|
default:
|
|
target = dst
|
|
}
|
|
|
|
seq := uint16(p.seq.Add(1))
|
|
msg := icmp.Message{
|
|
Type: ipv4.ICMPTypeEcho,
|
|
Code: 0,
|
|
Body: &icmp.Echo{
|
|
ID: 0,
|
|
Seq: int(seq),
|
|
Data: []byte("PING"),
|
|
},
|
|
}
|
|
buf, err := msg.Marshal(nil)
|
|
if err != nil {
|
|
return false
|
|
}
|
|
|
|
if _, err := p.conn.WriteTo(buf, target); err != nil {
|
|
return false
|
|
}
|
|
|
|
deadline := time.Now().Add(timeout)
|
|
rb := make([]byte, 1500)
|
|
for {
|
|
remaining := time.Until(deadline)
|
|
if remaining <= 0 {
|
|
return false
|
|
}
|
|
_ = p.conn.SetReadDeadline(time.Now().Add(remaining))
|
|
n, peer, err := p.conn.ReadFrom(rb)
|
|
if err != nil {
|
|
return false
|
|
}
|
|
rm, err := icmp.ParseMessage(ipv4.ICMPTypeEchoReply.Protocol(), rb[:n])
|
|
if err != nil {
|
|
continue
|
|
}
|
|
if rm.Type != ipv4.ICMPTypeEchoReply {
|
|
continue
|
|
}
|
|
var peerIP net.IP
|
|
switch a := peer.(type) {
|
|
case *net.UDPAddr:
|
|
peerIP = a.IP
|
|
case *net.IPAddr:
|
|
peerIP = a.IP
|
|
default:
|
|
peerIP = net.ParseIP(peer.String())
|
|
}
|
|
if peerIP != nil && peerIP.Equal(dst.IP) {
|
|
return true
|
|
}
|
|
}
|
|
}
|
|
|
|
func Ping(ip string, timeout time.Duration) (bool, error) {
|
|
p, err := NewPinger()
|
|
if err != nil {
|
|
return false, err
|
|
}
|
|
defer p.Close()
|
|
return p.Ping(ip, timeout), nil
|
|
}
|