tree 22d71ef353fe4e2f94a5c83e9b15e7bfa420e5df
parent 43a4dea4c9d44baae38ddc14b9b6d86fde4c8b88
author Steffen Klassert <steffen.klassert@secunet.com> 1304970185 +0000
committer David S. Miller <davem@davemloft.net> 1305065014 -0700

xfrm: Don't allow esn with disabled anti replay detection

Unlike the standard case, disabled anti replay detection needs some
nontrivial extra treatment on ESN. RFC 4303 states:

Note: If a receiver chooses to not enable anti-replay for an SA, then
the receiver SHOULD NOT negotiate ESN in an SA management protocol.
Use of ESN creates a need for the receiver to manage the anti-replay
window (in order to determine the correct value for the high-order
bits of the ESN, which are employed in the ICV computation), which is
generally contrary to the notion of disabling anti-replay for an SA.

So return an error if an ESN state with disabled anti replay detection
is inserted for now and add the extra treatment later if we need it.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: David S. Miller <davem@davemloft.net>