By passing "-V -d 001" now I get level-1 diagnostics for frames (i.e.
sending and receiving):

Slave:

   diag-frames-1-eth0: RECV 44 bytes at 1362665418.025198568 (type 0)
   diag-frames-1-eth0: RECV 44 bytes at 1362665418.025970153 (type 8)
   diag-frames-1-eth0: SENT 44 bytes at 1362665416.806670510 (delay_req)
   diag-frames-1-eth0: RECV 54 bytes at 1362665416.808217467 (type 9)

Master:

   diag-frames-1-eth0: SENT 64 bytes at 1362665415.430554014 (announce)
   diag-frames-1-eth0: SENT 44 bytes at 1362665416.612818573 (sync)
   diag-frames-1-eth0: SENT 44 bytes at 1362665416.613056524 (follow_up)
   diag-frames-1-eth0: RECV 44 bytes at 1362665416.807983194 (type 1)
   diag-frames-1-eth0: SENT 54 bytes at 1362665416.808206209 (delay_resp)

(note: we don't tell names at receive time because the frame is still
to be validated).
Signed-off-by: Alessandro Rubini <rubini@gnudd.com>