Improve netlink message debugging.

1. Add a method to convert a message to a string. The code didn't
   have anything that did just that; all string conversions were
   part of the debugging code. This method can be used by
   external callers that just want to parse raw messages obtained
   by other means (e.g., strace).
2. Teach the code about FRA_FWMASK.
3. Fix a bug in the parsing error handling due to attempting to
   catch the wrong exception.

Also fix a couple of lint errors.

Change-Id: I1915ab984934810ddbef7040c78d58e8657bb028
1 file changed
tree: d2dfa3d6047975db10bcc372704ff9ba3c635e1e
  1. net/