feat: idle sleep for proxmox LXCs

internal/net/ping.go

@@ -0,0 +1,115 @@
+package netutils
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"net"
+	"os"
+	"time"
+
+	"golang.org/x/net/icmp"
+	"golang.org/x/net/ipv4"
+	"golang.org/x/net/ipv6"
+)
+
+var (
+	ipv4EchoBytes []byte
+	ipv6EchoBytes []byte
+)
+
+func init() {
+	echoBody := &icmp.Echo{
+		ID:   os.Getpid() & 0xffff,
+		Seq:  1,
+		Data: []byte("Hello"),
+	}
+	ipv4Echo := &icmp.Message{
+		Type: ipv4.ICMPTypeEcho,
+		Body: echoBody,
+	}
+	ipv6Echo := &icmp.Message{
+		Type: ipv6.ICMPTypeEchoRequest,
+		Body: echoBody,
+	}
+	var err error
+	ipv4EchoBytes, err = ipv4Echo.Marshal(nil)
+	if err != nil {
+		panic(err)
+	}
+	ipv6EchoBytes, err = ipv6Echo.Marshal(nil)
+	if err != nil {
+		panic(err)
+	}
+}
+
+// Ping pings the IP address using ICMP.
+func Ping(ctx context.Context, ip net.IP) (bool, error) {
+	var msgBytes []byte
+	if ip.To4() != nil {
+		msgBytes = ipv4EchoBytes
+	} else {
+		msgBytes = ipv6EchoBytes
+	}
+
+	conn, err := icmp.ListenPacket("ip:icmp", ip.String())
+	if err != nil {
+		return false, err
+	}
+	defer conn.Close()
+
+	_, err = conn.WriteTo(msgBytes, &net.IPAddr{IP: ip})
+	if err != nil {
+		return false, err
+	}
+
+	err = conn.SetReadDeadline(time.Now().Add(1 * time.Second))
+	if err != nil {
+		return false, err
+	}
+
+	buf := make([]byte, 1500)
+	for {
+		select {
+		case <-ctx.Done():
+			return false, ctx.Err()
+		default:
+		}
+		n, _, err := conn.ReadFrom(buf)
+		if err != nil {
+			return false, err
+		}
+		m, err := icmp.ParseMessage(ipv4.ICMPTypeEchoReply.Protocol(), buf[:n])
+		if err != nil {
+			continue
+		}
+		if m.Type == ipv4.ICMPTypeEchoReply {
+			return true, nil
+		}
+	}
+}
+
+var pingDialer = &net.Dialer{
+	Timeout: 1 * time.Second,
+}
+
+// PingWithTCPFallback pings the IP address using ICMP and TCP fallback.
+//
+// If the ICMP ping fails due to permission error, it will try to connect to the specified port.
+func PingWithTCPFallback(ctx context.Context, ip net.IP, port int) (bool, error) {
+	ok, err := Ping(ctx, ip)
+	if err != nil {
+		if !errors.Is(err, os.ErrPermission) {
+			return false, err
+		}
+	} else {
+		return ok, nil
+	}
+
+	conn, err := pingDialer.DialContext(ctx, "tcp", fmt.Sprintf("%s:%d", ip, port))
+	if err != nil {
+		return false, err
+	}
+	defer conn.Close()
+	return true, nil
+}

internal/net/ping_test.go

@@ -0,0 +1,23 @@
+package netutils
+
+import (
+	"context"
+	"errors"
+	"net"
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestPing(t *testing.T) {
+	t.Run("localhost", func(t *testing.T) {
+		ok, err := Ping(context.Background(), net.ParseIP("127.0.0.1"))
+		// ping (ICMP) is not allowed for non-root users
+		if errors.Is(err, os.ErrPermission) {
+			t.Skip("permission denied")
+		}
+		require.NoError(t, err)
+		require.True(t, ok)
+	})
+}