After attaching the IV to the head during encryption, eseqiv does not
increase the encryption length by that amount.  As such the last block
of the actual plain text will be left unencrypted.

Fortunately the only user of this code hifn currently crashes so this
shouldn't affect anyone :)

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

The previous patch to move chainiv and eseqiv into blkcipher created
a section mismatch for the chainiv exit function which was also called
from __init.  This patch removes the __exit marking on it.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

For compatibility with dm-crypt initramfs setups it is useful to merge
chainiv/seqiv into the crypto_blkcipher module.  Since they're required
by most algorithms anyway this is an acceptable trade-off.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

This generator generates an IV based on a sequence number by xoring it
with a salt and then encrypting it with the same key as used to encrypt
the plain text.  This algorithm requires that the block size be equal
to the IV size.  It is mainly useful for CBC.

It has one noteworthy property that for IPsec the IV happens to lie
just before the plain text so the IV generation simply increases the
number of encrypted blocks by one.  Therefore the cost of this generator
is entirely dependent on the speed of the underlying cipher.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>