62 lines
1.6 KiB
Go
62 lines
1.6 KiB
Go
//go:build !darwin
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package tun
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import (
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"fmt"
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"net"
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"os"
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"os/exec"
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"strings"
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"github.com/songgao/water"
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)
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type linuxDevice struct {
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ifce *water.Interface
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}
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func createTUN(name string) (Device, error) {
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cfg := water.Config{DeviceType: water.TUN}
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cfg.Name = name
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ifce, err := water.New(cfg)
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if err != nil {
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return nil, fmt.Errorf("create tun: %w", err)
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}
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return &linuxDevice{ifce: ifce}, nil
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}
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func (d *linuxDevice) Name() string { return d.ifce.Name() }
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func (d *linuxDevice) Read(p []byte) (int, error) { return d.ifce.Read(p) }
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func (d *linuxDevice) Write(p []byte) (int, error) { return d.ifce.Write(p) }
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func (d *linuxDevice) Close() error { return d.ifce.Close() }
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func (d *linuxDevice) Configure(localIP net.IP, prefix int, peerIP net.IP) error {
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if err := execCmd("ip", "link", "set", "dev", d.Name(), "up"); err != nil {
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return err
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}
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if localIP == nil {
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return nil
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}
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localCidr := fmt.Sprintf("%s/%d", localIP.String(), prefix)
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if err := execCmd("ip", "addr", "add", "dev", d.Name(), localCidr, "peer", peerIP.String()); err != nil {
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// Fall back without peer (some kernels).
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return execCmd("ip", "addr", "add", "dev", d.Name(), localCidr)
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}
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return nil
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}
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func (d *linuxDevice) SetMTU(mtu int) error {
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return execCmd("ip", "link", "set", "dev", d.Name(), "mtu", fmt.Sprintf("%d", mtu))
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}
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func execCmd(name string, arg ...string) error {
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cmd := exec.Command(name, arg...)
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cmd.Stdout = os.Stdout
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cmd.Stderr = os.Stderr
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if err := cmd.Run(); err != nil {
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return fmt.Errorf("%s %s: %w", name, strings.Join(arg, " "), err)
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}
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return nil
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}
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