/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
/* Copyright(c) 2013, Intel Corp. */

/* Wrapper functions for Intel optimized implementation of AES-GCM */

#ifdef USE_HW_AES

#ifdef FREEBL_NO_DEPEND
#include "stubs.h"
#endif

#include "blapii.h"
#include "blapit.h"
#include "gcm.h"
#include "ctr.h"
#include "secerr.h"
#include "prtypes.h"
#include "pkcs11t.h"

#include <limits.h>

#include "intel-gcm.h"
#include "rijndael.h"

#include <emmintrin.h>
#include <tmmintrin.h>


struct intel_AES_GCMContextStr{
    unsigned char Htbl[16*AES_BLOCK_SIZE];
    unsigned char X0[AES_BLOCK_SIZE];
    unsigned char T[AES_BLOCK_SIZE];
    unsigned char CTR[AES_BLOCK_SIZE];
    AESContext *aes_context;
    unsigned long tagBits;
    unsigned long Alen;
    unsigned long Mlen;
};

intel_AES_GCMContext *intel_AES_GCM_CreateContext(void *context, 
               freeblCipherFunc cipher,
               const unsigned char *params, 
               unsigned int blocksize)
{
    intel_AES_GCMContext *gcm = NULL;
    AESContext *aes = (AESContext*)context;
    const CK_GCM_PARAMS *gcmParams = (const CK_GCM_PARAMS *)params;
    unsigned char buff[AES_BLOCK_SIZE]; /* aux buffer */
    
    int IV_whole_len = gcmParams->ulIvLen&(~0xf);
    int IV_remainder_len = gcmParams->ulIvLen&0xf;
    int AAD_whole_len = gcmParams->ulAADLen&(~0xf);
    int AAD_remainder_len = gcmParams->ulAADLen&0xf;
    
    __m128i BSWAP_MASK = _mm_setr_epi8(15,14,13,12,11,10,9,8,7,6,5,4,3,2,1,0);
    __m128i ONE = _mm_set_epi32(0,0,0,1);
    unsigned int j;
    SECStatus rv;

    if (blocksize != AES_BLOCK_SIZE) {
      PORT_SetError(SEC_ERROR_LIBRARY_FAILURE);
      return NULL;
    }
    gcm = PORT_ZNew(intel_AES_GCMContext);
    
    if (gcm == NULL) {
        return NULL;
    }
    /* initialize context fields */
    gcm->aes_context = aes;
    gcm->tagBits = gcmParams->ulTagBits;
    gcm->Alen = 0;
    gcm->Mlen = 0;
    /* first prepare H and its derivatives for ghash */
    intel_aes_gcmINIT(gcm->Htbl, (unsigned char*)aes->expandedKey, aes->Nr);
    /* Initial TAG value is zero*/
    _mm_storeu_si128((__m128i*)gcm->T, _mm_setzero_si128());
    _mm_storeu_si128((__m128i*)gcm->X0, _mm_setzero_si128());
    /* Init the counter */
    if(gcmParams->ulIvLen == 12) {
        _mm_storeu_si128((__m128i*)gcm->CTR, _mm_setr_epi32(((unsigned int*)gcmParams->pIv)[0], ((unsigned int*)gcmParams->pIv)[1], ((unsigned int*)gcmParams->pIv)[2], 0x01000000));
    } else {
        /* If IV size is not 96 bits, then the initial counter value is GHASH of the IV */
        intel_aes_gcmAAD(gcm->Htbl, gcmParams->pIv, IV_whole_len, gcm->T);
        /* Partial block */
        if(IV_remainder_len) {
            PORT_Memset(buff, 0, AES_BLOCK_SIZE);
            PORT_Memcpy(buff, gcmParams->pIv + IV_whole_len, IV_remainder_len);
            intel_aes_gcmAAD(gcm->Htbl, buff, AES_BLOCK_SIZE, gcm->T);
         }
         
         intel_aes_gcmTAG
         (
            gcm->Htbl,
            gcm->T,
            gcmParams->ulIvLen,
            0,
            gcm->X0,
            gcm->CTR
         );
        /* TAG should be zero again */
        _mm_storeu_si128((__m128i*)gcm->T, _mm_setzero_si128());
    }
    /* Encrypt the initial counter, will be used to encrypt the GHASH value, in the end */
    rv = (*cipher)(context, gcm->X0, &j, AES_BLOCK_SIZE, gcm->CTR, AES_BLOCK_SIZE, AES_BLOCK_SIZE);
    if (rv != SECSuccess) {
        goto loser;
    }
    /* Promote the counter by 1 */
    _mm_storeu_si128((__m128i*)gcm->CTR, _mm_shuffle_epi8(_mm_add_epi32(ONE, _mm_shuffle_epi8(_mm_loadu_si128((__m128i*)gcm->CTR), BSWAP_MASK)), BSWAP_MASK));

/*     Now hash AAD - it would actually make sense to seperate the context creation from the AAD, 
 *     because that would allow to reuse the H, which only changes when the AES key changes, 
 *     and not every package, like the IV and AAD */
    intel_aes_gcmAAD(gcm->Htbl, gcmParams->pAAD, AAD_whole_len, gcm->T);
    if(AAD_remainder_len) {
        PORT_Memset(buff, 0, AES_BLOCK_SIZE);
        PORT_Memcpy(buff, gcmParams->pAAD + AAD_whole_len, AAD_remainder_len);
        intel_aes_gcmAAD(gcm->Htbl, buff, AES_BLOCK_SIZE, gcm->T);
    }
    gcm->Alen += gcmParams->ulAADLen;
    return gcm;
    
    loser:
    if (gcm) {
        PORT_Free(gcm);
    }
    return NULL;
}

void intel_AES_GCM_DestroyContext(intel_AES_GCMContext *gcm, PRBool freeit)
{
    if (freeit) {
        PORT_Free(gcm);
    }
}

SECStatus intel_AES_GCM_EncryptUpdate(intel_AES_GCMContext *gcm, 
            unsigned char *outbuf,
            unsigned int *outlen, unsigned int maxout,
            const unsigned char *inbuf, unsigned int inlen,
            unsigned int blocksize)
{
    unsigned int tagBytes;
    unsigned char T[AES_BLOCK_SIZE];
    int j;

    tagBytes = (gcm->tagBits + (PR_BITS_PER_BYTE-1)) / PR_BITS_PER_BYTE;
    if (UINT_MAX - inlen < tagBytes) {
        PORT_SetError(SEC_ERROR_INPUT_LEN);
        return SECFailure;
    }
    if (maxout < inlen + tagBytes) {
        *outlen = inlen + tagBytes;
        PORT_SetError(SEC_ERROR_OUTPUT_LEN);
        return SECFailure;
    }

    intel_aes_gcmENC(
        inbuf,
        outbuf,
        gcm,
        inlen);

    gcm->Mlen += inlen;
      
    intel_aes_gcmTAG(
        gcm->Htbl,
        gcm->T,
        gcm->Mlen,
        gcm->Alen,
        gcm->X0,
        T);

    *outlen = inlen + tagBytes;

    for(j=0; j<tagBytes; j++)
    {
        outbuf[inlen+j] = T[j];
    }
    return SECSuccess;
}

SECStatus intel_AES_GCM_DecryptUpdate(intel_AES_GCMContext *gcm, 
            unsigned char *outbuf,
            unsigned int *outlen, unsigned int maxout,
            const unsigned char *inbuf, unsigned int inlen,
            unsigned int blocksize)
{
    unsigned int tagBytes;
    unsigned char T[AES_BLOCK_SIZE];
    const unsigned char *intag;

    tagBytes = (gcm->tagBits + (PR_BITS_PER_BYTE-1)) / PR_BITS_PER_BYTE;
 
    /* get the authentication block */
    if (inlen < tagBytes) {
        PORT_SetError(SEC_ERROR_INPUT_LEN);
        return SECFailure;
    }

    inlen -= tagBytes;
    intag = inbuf + inlen;

    if (maxout < inlen) {
        *outlen = inlen;
        PORT_SetError(SEC_ERROR_OUTPUT_LEN);
        return SECFailure;
    }

    intel_aes_gcmDEC(
         inbuf,
         outbuf,
         gcm,
         inlen);

    gcm->Mlen += inlen;
    intel_aes_gcmTAG(
         gcm->Htbl,
         gcm->T,
         gcm->Mlen,
         gcm->Alen,
         gcm->X0,
         T);

    if (NSS_SecureMemcmp(T, intag, tagBytes) != 0) {
        memset(outbuf, 0, inlen);
        *outlen = 0;
        /* force a CKR_ENCRYPTED_DATA_INVALID error at in softoken */
        PORT_SetError(SEC_ERROR_BAD_DATA);
        return SECFailure;
    }
    *outlen = inlen;

    return SECSuccess;
}

#endif