45 lines
955 B
Go
45 lines
955 B
Go
package tun
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import (
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"errors"
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"fmt"
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"os"
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"syscall"
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)
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var (
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ErrTUNInfo = errors.New("cannot get syscall stat info of TUN file")
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ErrTUNBadRdev = errors.New("TUN file has an unexpected rdev")
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)
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// Check checks the tunnel device specified by path is present and accessible.
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func (t *Tun) Check(path string) error {
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f, err := os.OpenFile(path, os.O_RDWR, 0)
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if err != nil {
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return fmt.Errorf("TUN device is not available: %w", err)
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}
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defer f.Close()
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info, err := f.Stat()
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if err != nil {
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return fmt.Errorf("getting stat information for TUN file: %w", err)
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}
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sys, ok := info.Sys().(*syscall.Stat_t)
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if !ok {
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return ErrTUNInfo
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}
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const expectedRdev = 2760 // corresponds to major 10 and minor 200
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if sys.Rdev != expectedRdev {
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return fmt.Errorf("%w: %d instead of expected %d",
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ErrTUNBadRdev, sys.Rdev, expectedRdev)
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}
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if err := f.Close(); err != nil {
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return fmt.Errorf("closing TUN device: %w", err)
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}
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return nil
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}
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