As architecture specific drivers need a software fallback, export a
ChaCha20 en-/decryption function together with some helpers in a header
file.
Signed-off-by: NMartin Willi <martin@strongswan.org>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

This patch converts rfc7539 and rfc7539esp to the new AEAD interface.
The test vectors for rfc7539esp have also been updated to include
the IV.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
Tested-by: NMartin Willi <martin@strongswan.org>

The Poly1305 authenticator requires a unique key for each generated tag. This
implies that we can't set the key per tfm, as multiple users set individual
keys. Instead we pass a desc specific key as the first two blocks of the
message to authenticate in update().
Signed-off-by: NMartin Willi <martin@strongswan.org>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

draft-ietf-ipsecme-chacha20-poly1305 defines the use of ChaCha20/Poly1305 in
ESP. It uses additional four byte key material as a salt, which is then used
with an 8 byte IV to form the ChaCha20 nonce as defined in the RFC7539.
Signed-off-by: NMartin Willi <martin@strongswan.org>
Acked-by: NSteffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

This AEAD uses a chacha20 ablkcipher and a poly1305 ahash to construct the
ChaCha20-Poly1305 AEAD as defined in RFC7539. It supports both synchronous and
asynchronous operations, even if we currently have no async chacha20 or poly1305
drivers.
Signed-off-by: NMartin Willi <martin@strongswan.org>
Acked-by: NSteffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>