cbc.h

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#ifndef _GPXE_CBC_H
#define _GPXE_CBC_H

/** @file
 *
 * Cipher-block chaining
 *
 */

FILE_LICENCE ( GPL2_OR_LATER );

#include <gpxe/crypto.h>

/**
 * Set key
 *
 * @v ctx               Context
 * @v key               Key
 * @v keylen            Key length
 * @v raw_cipher        Underlying cipher algorithm
 * @v cbc_ctx           CBC context
 * @ret rc              Return status code
 */
static inline int cbc_setkey ( void *ctx, const void *key, size_t keylen,
                               struct cipher_algorithm *raw_cipher,
                               void *cbc_ctx __unused ) {

        return cipher_setkey ( raw_cipher, ctx, key, keylen );
}

/**
 * Set initialisation vector
 *
 * @v ctx               Context
 * @v iv                Initialisation vector
 * @v raw_cipher        Underlying cipher algorithm
 * @v cbc_ctx           CBC context
 */
static inline void cbc_setiv ( void *ctx __unused, const void *iv,
                               struct cipher_algorithm *raw_cipher,
                               void *cbc_ctx ) {
        memcpy ( cbc_ctx, iv, raw_cipher->blocksize );
}

extern void cbc_encrypt ( void *ctx, const void *src, void *dst,
                          size_t len, struct cipher_algorithm *raw_cipher,
                          void *cbc_ctx );
extern void cbc_decrypt ( void *ctx, const void *src, void *dst,
                          size_t len, struct cipher_algorithm *raw_cipher,
                          void *cbc_ctx );

/**
 * Create a cipher-block chaining mode of behaviour of an existing cipher
 *
 * @v _cbc_name         Name for the new CBC cipher
 * @v _cbc_cipher       New cipher algorithm
 * @v _raw_cipher       Underlying cipher algorithm
 * @v _raw_context      Context structure for the underlying cipher
 * @v _blocksize        Cipher block size
 */
#define CBC_CIPHER( _cbc_name, _cbc_cipher, _raw_cipher, _raw_context,  \
                    _blocksize )                                        \
struct _cbc_name ## _context {                                          \
        _raw_context raw_ctx;                                           \
        uint8_t cbc_ctx[_blocksize];                                    \
};                                                                      \
static int _cbc_name ## _setkey ( void *ctx, const void *key,           \
                                  size_t keylen ) {                     \
        struct _cbc_name ## _context * _cbc_name ## _ctx = ctx;         \
        return cbc_setkey ( &_cbc_name ## _ctx->raw_ctx, key, keylen,   \
                            &_raw_cipher, &_cbc_name ## _ctx->cbc_ctx );\
}                                                                       \
static void _cbc_name ## _setiv ( void *ctx, const void *iv ) {         \
        struct _cbc_name ## _context * _cbc_name ## _ctx = ctx;         \
        cbc_setiv ( &_cbc_name ## _ctx->raw_ctx, iv,                    \
                    &_raw_cipher, &aes_cbc_ctx->cbc_ctx );              \
}                                                                       \
static void _cbc_name ## _encrypt ( void *ctx, const void *src,         \
                                    void *dst, size_t len ) {           \
        struct _cbc_name ## _context * _cbc_name ## _ctx = ctx;         \
        cbc_encrypt ( &_cbc_name ## _ctx->raw_ctx, src, dst, len,       \
                      &_raw_cipher, &aes_cbc_ctx->cbc_ctx );            \
}                                                                       \
static void _cbc_name ## _decrypt ( void *ctx, const void *src,         \
                                    void *dst, size_t len ) {           \
        struct _cbc_name ## _context * _cbc_name ## _ctx = ctx;         \
        cbc_decrypt ( &_cbc_name ## _ctx->raw_ctx, src, dst, len,       \
                      &_raw_cipher, &aes_cbc_ctx->cbc_ctx );            \
}                                                                       \
struct cipher_algorithm _cbc_cipher = {                                 \
        .name           = #_cbc_name,                                   \
        .ctxsize        = sizeof ( struct _cbc_name ## _context ),      \
        .blocksize      = _blocksize,                                   \
        .setkey         = _cbc_name ## _setkey,                         \
        .setiv          = _cbc_name ## _setiv,                          \
        .encrypt        = _cbc_name ## _encrypt,                        \
        .decrypt        = _cbc_name ## _decrypt,                        \
};

#endif /* _GPXE_CBC_H */