Hi: This series of patches takes the opportunity of the AEAD conversion to adjust the interface so that it is more optimal for the intended use-cases.
As it stands, AEAD takes two separate SG lists, one containing the asssociated data (AD) and one containing the plain/cipher text. These two lists have to be combined when we generate the ICV. In order to provide the best performance, many AEAD algorithms try to stitch these two lists together into a single contiguous SG entry where possible. Worse, with IPsec there is also an IV involved that needs to be added into the mix. The end result is a lot of black magic all spread out through the crypto stack. You just have to take a look at the complexity in crypto/authenc.c to know what I'm talking about (not to mention crypto/authencesn.c). Another wart in the system is IV generation. This is exclusively used by IPsec. However, it carries with it almost an entire operation type in the form of givencrypt. Again a lot of complexity has been added in order to support this. So this series slightly adjusts the AEAD interface in an attempt to solve these two issues. Firstly the AD is now placed into the same SG list as the plain/cipher text. This removes the need to do any stitching. As the primary user of AEAD, IPsec naturally has a contiguous buffer containing the AD and plain/cipher text, this simplifies esp4/esp6 quite a bit. Secondly IV generation is now carried out in explicit but normal AEAD algorithms. The generated IV is simply part of the cipher text. This means that we can kill at least half of the AEAD geniv code and all of the ablkcipher geniv code. It also means that authenc and other IPsec-specific algorithms no longer has to do IV stitching. This series only creates the new interface. The actual conversion will be carried out in subsequent series. The old interface will be maintained until the conversion is complete. Cheers, -- Email: Herbert Xu <herb...@gondor.apana.org.au> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt -- To unsubscribe from this list: send the line "unsubscribe linux-crypto" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
