xfrm: Assign esn pointers when cloning a state

When we clone a xfrm state we have to assign the replay_esn
and the preplay_esn pointers to the state if we use the
new replay detection method. To this end, we add a
xfrm_replay_clone() function that allocates memory for
the replay detection and takes over the necessary values
from the original state.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/xfrm/xfrm_state.c

@@ -1181,6 +1181,12 @@ static struct xfrm_state *xfrm_state_clone(struct xfrm_state *orig, int *errp)
 			goto error;
 	}
 
+	if (orig->replay_esn) {
+		err = xfrm_replay_clone(x, orig);
+		if (err)
+			goto error;
+	}
+
 	memcpy(&x->mark, &orig->mark, sizeof(x->mark));
 
 	err = xfrm_init_state(x);