chore(all): review error wrappings

- remove repetitive `cannot` and `failed` prefixes
- rename `unmarshaling` to `decoding`

internal/tun/check.go

@@ -22,7 +22,7 @@ func (t *Tun) Check(path string) error {
 
 	info, err := f.Stat()
 	if err != nil {
-		return fmt.Errorf("cannot stat TUN file: %w", err)
+		return fmt.Errorf("getting stat information for TUN file: %w", err)
 	}
 
 	sys, ok := info.Sys().(*syscall.Stat_t)
@@ -37,7 +37,7 @@ func (t *Tun) Check(path string) error {
 	}
 
 	if err := f.Close(); err != nil {
-		return fmt.Errorf("cannot close TUN device: %w", err)
+		return fmt.Errorf("closing TUN device: %w", err)
 	}
 
 	return nil

internal/tun/create.go

@@ -22,18 +22,18 @@ func (t *Tun) Create(path string) error {
 	dev := unix.Mkdev(major, minor)
 	err := t.mknod(path, unix.S_IFCHR, int(dev))
 	if err != nil {
-		return fmt.Errorf("cannot create TUN device file node: %w", err)
+		return fmt.Errorf("creating TUN device file node: %w", err)
 	}
 
 	fd, err := unix.Open(path, 0, 0)
 	if err != nil {
-		return fmt.Errorf("cannot Unix Open TUN device file: %w", err)
+		return fmt.Errorf("unix opening TUN device file: %w", err)
 	}
 
 	const nonBlocking = true
 	err = unix.SetNonblock(fd, nonBlocking)
 	if err != nil {
-		return fmt.Errorf("cannot set non block to TUN device file descriptor: %w", err)
+		return fmt.Errorf("setting non block to TUN device file descriptor: %w", err)
 	}
 
 	return nil

internal/tun/tun_test.go

@@ -40,7 +40,7 @@ func Test_Tun(t *testing.T) {
 	// Create TUN device fail as file exists
 	err = tun.Create(path)
 	require.Error(t, err)
-	require.Equal(t, "cannot create TUN device file node: file exists", err.Error())
+	require.EqualError(t, err, "creating TUN device file node: file exists")
 
 	// Remove simple file
 	err = os.Remove(path)