looping cursor position in dired

[Sebastian Luque]

Hello,

Before I start writing something too complicated, what is the best way to
allow the cursor to loop through the dired buffer?  i.e. if the cursor is
at the end of the buffer and you hit [up] (dired-next-line), then the
cursor would move to the first line; likewise for the opposite action.

Thanks,

-- 
Sebastian P. Luque