XFRM proc - /proc/net/xfrm_* files
  ==================================
  Masahide NAKAMURA <nakam@linux-ipv6.org>
  
  
  Transformation Statistics
  -------------------------
  xfrm_proc is a statistics shown factor dropped by transformation
  for developer.
  It is a counter designed from current transformation source code
  and defined like linux private MIB.
  
  Inbound statistics
  ~~~~~~~~~~~~~~~~~~
  XfrmInError:
  	All errors which is not matched others
  XfrmInBufferError:
  	No buffer is left
  XfrmInHdrError:
  	Header error
  XfrmInNoStates:
  	No state is found
  	i.e. Either inbound SPI, address, or IPsec protocol at SA is wrong
  XfrmInStateProtoError:
  	Transformation protocol specific error
  	e.g. SA key is wrong
  XfrmInStateModeError:
  	Transformation mode specific error

  XfrmInStateSeqError:
  	Sequence error
  	i.e. Sequence number is out of window

  XfrmInStateExpired:
  	State is expired
  XfrmInStateMismatch:
  	State has mismatch option
  	e.g. UDP encapsulation type is mismatch
  XfrmInStateInvalid:
  	State is invalid
  XfrmInTmplMismatch:
  	No matching template for states
  	e.g. Inbound SAs are correct but SP rule is wrong
  XfrmInNoPols:
  	No policy is found for states
  	e.g. Inbound SAs are correct but no SP is found
  XfrmInPolBlock:
  	Policy discards
  XfrmInPolError:
  	Policy error
  
  Outbound errors
  ~~~~~~~~~~~~~~~
  XfrmOutError:
  	All errors which is not matched others
  XfrmOutBundleGenError:
  	Bundle generation error
  XfrmOutBundleCheckError:
  	Bundle check error
  XfrmOutNoStates:
  	No state is found
  XfrmOutStateProtoError:
  	Transformation protocol specific error
  XfrmOutStateModeError:
  	Transformation mode specific error

  XfrmOutStateSeqError:
  	Sequence error
  	i.e. Sequence number overflow

  XfrmOutStateExpired:
  	State is expired
  XfrmOutPolBlock:
  	Policy discards
  XfrmOutPolDead:
  	Policy is dead
  XfrmOutPolError:
  	Policy error