Make some cleanups in policy validation, and add tools to expose the policies to userspace.
This lets userspace discover what the appropriate data for an element is. Note that NLA_UNSPEC items are omitted as they're rejected in strict validation mode so their policy entries should be changed to NLA_MIN_LEN - this is just a representation change. Eventually, I'd like to add a separation between input and output policies (currently only the input policy is exposed), but that needs some extra work to add "overrides". johannes
