This is xnu-8019. See this file in:
/* Copyright (c) (2010,2011,2012,2014,2015,2016,2017,2018,2019) Apple Inc. All rights reserved.
 * corecrypto is licensed under Apple Inc.’s Internal Use License Agreement (which
 * is contained in the License.txt file distributed with corecrypto) and only to 
 * people who accept that license. IMPORTANT:  Any license rights granted to you by 
 * Apple Inc. (if any) are limited to internal use within your organization only on 
 * devices and computers you own or control, for the sole purpose of verifying the 
 * security characteristics and correct functioning of the Apple Software.  You may 
 * not, directly or indirectly, redistribute the Apple Software or any portions thereof.


#include <corecrypto/cc.h>
#include <corecrypto/ccdigest.h>

/* An hmac_ctx_t is normally allocated as an array of these. */
struct cchmac_ctx {
    uint8_t b[1];

typedef struct cchmac_ctx* cchmac_ctx_t;

#define cchmac_ctx_size(STATE_SIZE, BLOCK_SIZE) (cc_pad_align(ccdigest_ctx_size(STATE_SIZE, BLOCK_SIZE)) + (STATE_SIZE))
#define cchmac_di_size(_di_)  (cchmac_ctx_size((_di_)->state_size, (_di_)->block_size))

#define cchmac_ctx_n(STATE_SIZE, BLOCK_SIZE)  ccn_nof_size(cchmac_ctx_size((STATE_SIZE), (BLOCK_SIZE)))

#define cchmac_ctx_decl(STATE_SIZE, BLOCK_SIZE, _name_) cc_ctx_decl(struct cchmac_ctx, cchmac_ctx_size(STATE_SIZE, BLOCK_SIZE), _name_)
#define cchmac_ctx_clear(STATE_SIZE, BLOCK_SIZE, _name_) cc_clear(cchmac_ctx_size(STATE_SIZE, BLOCK_SIZE), _name_)
#define cchmac_di_decl(_di_, _name_) cchmac_ctx_decl((_di_)->state_size, (_di_)->block_size, _name_)
#define cchmac_di_clear(_di_, _name_) cchmac_ctx_clear((_di_)->state_size, (_di_)->block_size, _name_)

/* Return a ccdigest_ctx_t which can be accesed with the macros in ccdigest.h */
#define cchmac_digest_ctx(_di_, HC)    ((ccdigest_ctx_t)(HC))

/* Accesors for ostate fields, this is all cchmac_ctx_t adds to the ccdigest_ctx_t. */
#define cchmac_ostate(_di_, HC)    ((struct ccdigest_state *)(((cchmac_ctx_t)(HC))->b + cc_pad_align(ccdigest_di_size(_di_))))
#define cchmac_ostate8(_di_, HC)   (ccdigest_u8(cchmac_ostate(_di_, HC)))
#define cchmac_ostate32(_di_, HC)  (ccdigest_u32(cchmac_ostate(_di_, HC)))
#define cchmac_ostate64(_di_, HC)  (ccdigest_u64(cchmac_ostate(_di_, HC)))
#define cchmac_ostateccn(_di_, HC) (ccdigest_ccn(cchmac_ostate(_di_, HC)))

/* Convenience accessors for ccdigest_ctx_t fields. */
#define cchmac_istate(_di_, HC)    ccdigest_state(_di_, ((ccdigest_ctx_t)(HC)))
#define cchmac_istate8(_di_, HC)   ccdigest_u8(cchmac_istate(_di_, HC))
#define cchmac_istate32(_di_, HC)  ccdigest_u32(cchmac_istate(_di_, HC))
#define cchmac_istate64(_di_, HC)  ccdigest_u64(cchmac_istate(_di_, HC))
#define cchmac_istateccn(_di_, HC) ccdigest_ccn(cchmac_istate(_di_, HC))

#define cchmac_data(_di_, HC)      ccdigest_data(_di_, ((ccdigest_ctx_t)(HC)))
#define cchmac_num(_di_, HC)       ccdigest_num(_di_, ((ccdigest_ctx_t)(HC)))
#define cchmac_nbits(_di_, HC)     ccdigest_nbits(_di_, ((ccdigest_ctx_t)(HC)))

void cchmac_init(const struct ccdigest_info *di, cchmac_ctx_t ctx,
                 size_t key_len, const void *key);
void cchmac_update(const struct ccdigest_info *di, cchmac_ctx_t ctx,
                   size_t data_len, const void *data);
void cchmac_final(const struct ccdigest_info *di, cchmac_ctx_t ctx,
                  unsigned char *mac);

void cchmac(const struct ccdigest_info *di, size_t key_len,
            const void *key, size_t data_len, const void *data,
            unsigned char *mac);

#endif /* _CORECRYPTO_CCHMAC_H_ */