/* poly1305.c

 *

 * Copyright (C) 2006-2022 wolfSSL Inc.

 *

 * This file is part of wolfSSL.

 *

 * wolfSSL is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

 * wolfSSL is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335, USA

 */

/*

DESCRIPTION

This library contains implementation for the Poly1305 authenticator.

Based off the public domain implementations by Andrew Moon

and Daniel J. Bernstein

*/

#ifdef HAVE_CONFIG_H

    #include <config.h>

#endif

#include <wolfssl/wolfcrypt/settings.h>

#ifdef HAVE_POLY1305

#include <wolfssl/wolfcrypt/poly1305.h>

#include <wolfssl/wolfcrypt/error-crypt.h>

#include <wolfssl/wolfcrypt/logging.h>

#include <wolfssl/wolfcrypt/cpuid.h>

#ifdef NO_INLINE

    #include <wolfssl/wolfcrypt/misc.h>

#else

    #define WOLFSSL_MISC_INCLUDED

    #include <wolfcrypt/src/misc.c>

#endif

#ifdef CHACHA_AEAD_TEST

    #include <stdio.h>

#endif

#ifdef _MSC_VER

    /* 4127 warning constant while(1)  */

    #pragma warning(disable: 4127)

#endif

#ifdef USE_INTEL_SPEEDUP

    #include <emmintrin.h>

    #include <immintrin.h>

    #if defined(__GNUC__) && ((__GNUC__ < 4) || \

                              (__GNUC__ == 4 && __GNUC_MINOR__ <= 8))

        #undef  NO_AVX2_SUPPORT

        #define NO_AVX2_SUPPORT

    #endif

    #if defined(__clang__) && ((__clang_major__ < 3) || \

                               (__clang_major__ == 3 && __clang_minor__ <= 5))

        #define NO_AVX2_SUPPORT

    #elif defined(__clang__) && defined(NO_AVX2_SUPPORT)

        #undef NO_AVX2_SUPPORT

    #endif

    #define HAVE_INTEL_AVX1

    #ifndef NO_AVX2_SUPPORT

        #define HAVE_INTEL_AVX2

    #endif

#endif

#ifdef USE_INTEL_SPEEDUP

static word32 intel_flags = 0;

static word32 cpu_flags_set = 0;

#endif

#if defined(USE_INTEL_SPEEDUP) || defined(POLY130564)

    #if defined(_MSC_VER)

        #define POLY1305_NOINLINE __declspec(noinline)

    #elif defined(__GNUC__)

        #define POLY1305_NOINLINE __attribute__((noinline))

    #else

        #define POLY1305_NOINLINE

    #endif

    #if defined(_MSC_VER)

        #include <intrin.h>

        typedef struct word128 {

            word64 lo;

            word64 hi;

        } word128;

        #define MUL(out, x, y) out.lo = _umul128((x), (y), &out.hi)

        #define ADD(out, in) { word64 t = out.lo; out.lo += in.lo; \

                               out.hi += (out.lo < t) + in.hi; }

        #define ADDLO(out, in) { word64 t = out.lo; out.lo += in; \

                                 out.hi += (out.lo < t); }

        #define SHR(in, shift) (__shiftright128(in.lo, in.hi, (shift)))

        #define LO(in) (in.lo)

    #elif defined(__GNUC__)

        #if defined(__SIZEOF_INT128__)

            PEDANTIC_EXTENSION typedef unsigned __int128 word128;

        #else

            typedef unsigned word128 __attribute__((mode(TI)));

        #endif

        #define MUL(out, x, y) out = ((word128)(x) * (y))

        #define ADD(out, in) (out) += (in)

        #define ADDLO(out, in) (out) += (in)

        #define SHR(in, shift) (word64)((in) >> (shift))

        #define LO(in) (word64)(in)

    #endif

#endif

#ifdef USE_INTEL_SPEEDUP

#ifdef __cplusplus

    extern "C" {

#endif

#ifdef HAVE_INTEL_AVX1

/* Process one block (16 bytes) of data.

 *

 * ctx  Poly1305 context.

 * m    One block of message data.

 */

extern void poly1305_block_avx(Poly1305* ctx, const unsigned char *m);

/* Process multiple blocks (n * 16 bytes) of data.

 *

 * ctx    Poly1305 context.

 * m      Blocks of message data.

 * bytes  The number of bytes to process.

 */

extern void poly1305_blocks_avx(Poly1305* ctx, const unsigned char* m,

                                size_t bytes);

/* Set the key to use when processing data.

 * Initialize the context.

 *

 * ctx  Poly1305 context.

 * key  The key data (16 bytes).

 */

extern void poly1305_setkey_avx(Poly1305* ctx, const byte* key);

/* Calculate the final result - authentication data.

 * Zeros out the private data in the context.

 *

 * ctx  Poly1305 context.

 * mac  Buffer to hold 16 bytes.

 */

extern void poly1305_final_avx(Poly1305* ctx, byte* mac);

#endif

#ifdef HAVE_INTEL_AVX2

/* Process multiple blocks (n * 16 bytes) of data.

 *

 * ctx    Poly1305 context.

 * m      Blocks of message data.

 * bytes  The number of bytes to process.

 */

extern void poly1305_blocks_avx2(Poly1305* ctx, const unsigned char* m,

                                 size_t bytes);

/* Calculate R^1, R^2, R^3 and R^4 and store them in the context.

 *

 * ctx    Poly1305 context.

 */

extern void poly1305_calc_powers_avx2(Poly1305* ctx);

/* Set the key to use when processing data.

 * Initialize the context.

 * Calls AVX set key function as final function calls AVX code.

 *

 * ctx  Poly1305 context.

 * key  The key data (16 bytes).

 */

extern void poly1305_setkey_avx2(Poly1305* ctx, const byte* key);

/* Calculate the final result - authentication data.

 * Zeros out the private data in the context.

 * Calls AVX final function to quickly process last blocks.

 *

 * ctx  Poly1305 context.

 * mac  Buffer to hold 16 bytes - authentication data.

 */

extern void poly1305_final_avx2(Poly1305* ctx, byte* mac);

#endif

#ifdef __cplusplus

    }  /* extern "C" */

#endif

#elif defined(POLY130564)

#ifndef WOLFSSL_ARMASM

    static word64 U8TO64(const byte* p)

    {

        return

            (((word64)(p[0] & 0xff)      ) |

             ((word64)(p[1] & 0xff) <<  8) |

             ((word64)(p[2] & 0xff) << 16) |

             ((word64)(p[3] & 0xff) << 24) |

             ((word64)(p[4] & 0xff) << 32) |

             ((word64)(p[5] & 0xff) << 40) |

             ((word64)(p[6] & 0xff) << 48) |

             ((word64)(p[7] & 0xff) << 56));

    }

    static void U64TO8(byte* p, word64 v) {

        p[0] = (v      ) & 0xff;

        p[1] = (v >>  8) & 0xff;

        p[2] = (v >> 16) & 0xff;

        p[3] = (v >> 24) & 0xff;

        p[4] = (v >> 32) & 0xff;

        p[5] = (v >> 40) & 0xff;

        p[6] = (v >> 48) & 0xff;

        p[7] = (v >> 56) & 0xff;

    }

#endif/* WOLFSSL_ARMASM */

#else /* if not 64 bit then use 32 bit */

    static word32 U8TO32(const byte *p)

    {

        return

            (((word32)(p[0] & 0xff)      ) |

             ((word32)(p[1] & 0xff) <<  8) |

             ((word32)(p[2] & 0xff) << 16) |

             ((word32)(p[3] & 0xff) << 24));

    }

    static void U32TO8(byte *p, word32 v) {

        p[0] = (byte)((v      ) & 0xff);

        p[1] = (byte)((v >>  8) & 0xff);

        p[2] = (byte)((v >> 16) & 0xff);

        p[3] = (byte)((v >> 24) & 0xff);

    }

#endif

/* convert 32-bit unsigned to little endian 64 bit type as byte array */

static WC_INLINE void u32tole64(const word32 inLe32, byte outLe64[8])

{

#ifndef WOLFSSL_X86_64_BUILD

    outLe64[0] = (byte)(inLe32  & 0x000000FF);

    outLe64[1] = (byte)((inLe32 & 0x0000FF00) >> 8);

    outLe64[2] = (byte)((inLe32 & 0x00FF0000) >> 16);

    outLe64[3] = (byte)((inLe32 & 0xFF000000) >> 24);

    outLe64[4] = 0;

    outLe64[5] = 0;

    outLe64[6] = 0;

    outLe64[7] = 0;

#else

    *(word64*)outLe64 = inLe32;

#endif

}

#if !defined(WOLFSSL_ARMASM) || !defined(__aarch64__)

/*

This local function operates on a message with a given number of bytes

with a given ctx pointer to a Poly1305 structure.

*/

static int poly1305_blocks(Poly1305* ctx, const unsigned char *m,

                     size_t bytes)

{

#ifdef USE_INTEL_SPEEDUP

    /* AVX2 is handled in wc_Poly1305Update. */

    SAVE_VECTOR_REGISTERS(return _svr_ret;);

    poly1305_blocks_avx(ctx, m, bytes);

    RESTORE_VECTOR_REGISTERS();

    return 0;

#elif defined(POLY130564)

    const word64 hibit = (ctx->finished) ? 0 : ((word64)1 << 40); /* 1 << 128 */

    word64 r0,r1,r2;

    word64 s1,s2;

    word64 h0,h1,h2;

    word64 c;

    word128 d0,d1,d2,d;

    r0 = ctx->r[0];

    r1 = ctx->r[1];

    r2 = ctx->r[2];

    h0 = ctx->h[0];

    h1 = ctx->h[1];

    h2 = ctx->h[2];

    s1 = r1 * (5 << 2);

    s2 = r2 * (5 << 2);

    while (bytes >= POLY1305_BLOCK_SIZE) {

        word64 t0,t1;

        /* h += m[i] */

        t0 = U8TO64(&m[0]);

        t1 = U8TO64(&m[8]);

        h0 += (( t0                    ) & 0xfffffffffff);

        h1 += (((t0 >> 44) | (t1 << 20)) & 0xfffffffffff);

        h2 += (((t1 >> 24)             ) & 0x3ffffffffff) | hibit;

        /* h *= r */

        MUL(d0, h0, r0); MUL(d, h1, s2); ADD(d0, d); MUL(d, h2, s1); ADD(d0, d);

        MUL(d1, h0, r1); MUL(d, h1, r0); ADD(d1, d); MUL(d, h2, s2); ADD(d1, d);

        MUL(d2, h0, r2); MUL(d, h1, r1); ADD(d2, d); MUL(d, h2, r0); ADD(d2, d);

        /* (partial) h %= p */

                      c = SHR(d0, 44); h0 = LO(d0) & 0xfffffffffff;

        ADDLO(d1, c); c = SHR(d1, 44); h1 = LO(d1) & 0xfffffffffff;

        ADDLO(d2, c); c = SHR(d2, 42); h2 = LO(d2) & 0x3ffffffffff;

        h0  += c * 5; c = (h0 >> 44);  h0 =    h0  & 0xfffffffffff;

        h1  += c;

        m += POLY1305_BLOCK_SIZE;

        bytes -= POLY1305_BLOCK_SIZE;

    }

    ctx->h[0] = h0;

    ctx->h[1] = h1;

    ctx->h[2] = h2;

    return 0;

#else /* if not 64 bit then use 32 bit */

    const word32 hibit = (ctx->finished) ? 0 : ((word32)1 << 24); /* 1 << 128 */

    word32 r0,r1,r2,r3,r4;

    word32 s1,s2,s3,s4;

    word32 h0,h1,h2,h3,h4;

    word64 d0,d1,d2,d3,d4;

    word32 c;

    r0 = ctx->r[0];

    r1 = ctx->r[1];

    r2 = ctx->r[2];

    r3 = ctx->r[3];

    r4 = ctx->r[4];

    s1 = r1 * 5;

    s2 = r2 * 5;

    s3 = r3 * 5;

    s4 = r4 * 5;

    h0 = ctx->h[0];

    h1 = ctx->h[1];

    h2 = ctx->h[2];

    h3 = ctx->h[3];

    h4 = ctx->h[4];

    while (bytes >= POLY1305_BLOCK_SIZE) {

        /* h += m[i] */

        h0 += (U8TO32(m+ 0)     ) & 0x3ffffff;

        h1 += (U8TO32(m+ 3) >> 2) & 0x3ffffff;

        h2 += (U8TO32(m+ 6) >> 4) & 0x3ffffff;

        h3 += (U8TO32(m+ 9) >> 6) & 0x3ffffff;

        h4 += (U8TO32(m+12) >> 8) | hibit;

        /* h *= r */

        d0 = ((word64)h0 * r0) + ((word64)h1 * s4) + ((word64)h2 * s3) +

             ((word64)h3 * s2) + ((word64)h4 * s1);

        d1 = ((word64)h0 * r1) + ((word64)h1 * r0) + ((word64)h2 * s4) +

             ((word64)h3 * s3) + ((word64)h4 * s2);

        d2 = ((word64)h0 * r2) + ((word64)h1 * r1) + ((word64)h2 * r0) +

             ((word64)h3 * s4) + ((word64)h4 * s3);

        d3 = ((word64)h0 * r3) + ((word64)h1 * r2) + ((word64)h2 * r1) +

             ((word64)h3 * r0) + ((word64)h4 * s4);

        d4 = ((word64)h0 * r4) + ((word64)h1 * r3) + ((word64)h2 * r2) +

             ((word64)h3 * r1) + ((word64)h4 * r0);

        /* (partial) h %= p */

                      c = (word32)(d0 >> 26); h0 = (word32)d0 & 0x3ffffff;

        d1 += c;      c = (word32)(d1 >> 26); h1 = (word32)d1 & 0x3ffffff;

        d2 += c;      c = (word32)(d2 >> 26); h2 = (word32)d2 & 0x3ffffff;

        d3 += c;      c = (word32)(d3 >> 26); h3 = (word32)d3 & 0x3ffffff;

        d4 += c;      c = (word32)(d4 >> 26); h4 = (word32)d4 & 0x3ffffff;

        h0 += c * 5;  c =  (h0 >> 26); h0 =                h0 & 0x3ffffff;

        h1 += c;

        m += POLY1305_BLOCK_SIZE;

        bytes -= POLY1305_BLOCK_SIZE;

    }

    ctx->h[0] = h0;

    ctx->h[1] = h1;

    ctx->h[2] = h2;

    ctx->h[3] = h3;

    ctx->h[4] = h4;

    return 0;

#endif /* end of 64 bit cpu blocks or 32 bit cpu */

}

/*

This local function is used for the last call when a message with a given

number of bytes is less than the block size.

*/

static int poly1305_block(Poly1305* ctx, const unsigned char *m)

{

#ifdef USE_INTEL_SPEEDUP

    /* No call to poly1305_block when AVX2, AVX2 does 4 blocks at a time. */

    SAVE_VECTOR_REGISTERS(return _svr_ret;);

    poly1305_block_avx(ctx, m);

    RESTORE_VECTOR_REGISTERS();

    return 0;

#else

    return poly1305_blocks(ctx, m, POLY1305_BLOCK_SIZE);

#endif

}

#endif /* !defined(WOLFSSL_ARMASM) || !defined(__aarch64__) */

#if !defined(WOLFSSL_ARMASM) || !defined(__aarch64__)

int wc_Poly1305SetKey(Poly1305* ctx, const byte* key, word32 keySz)

{

#if defined(POLY130564) && !defined(USE_INTEL_SPEEDUP)

    word64 t0,t1;

#endif

    if (key == NULL)

        return BAD_FUNC_ARG;

#ifdef CHACHA_AEAD_TEST

    word32 k;

    printf("Poly key used:\n");

    for (k = 0; k < keySz; k++) {

        printf("%02x", key[k]);

        if ((k+1) % 8 == 0)

            printf("\n");

    }

    printf("\n");

#endif

    if (keySz != 32 || ctx == NULL)

        return BAD_FUNC_ARG;

#ifdef USE_INTEL_SPEEDUP

    if (!cpu_flags_set) {

        intel_flags = cpuid_get_flags();

        cpu_flags_set = 1;

    }

    SAVE_VECTOR_REGISTERS(return _svr_ret;);

    #ifdef HAVE_INTEL_AVX2

    if (IS_INTEL_AVX2(intel_flags))

        poly1305_setkey_avx2(ctx, key);

    else

    #endif

        poly1305_setkey_avx(ctx, key);

    RESTORE_VECTOR_REGISTERS();

#elif defined(POLY130564)

    /* r &= 0xffffffc0ffffffc0ffffffc0fffffff */

    t0 = U8TO64(key + 0);

    t1 = U8TO64(key + 8);

    ctx->r[0] = ( t0                    ) & 0xffc0fffffff;

    ctx->r[1] = ((t0 >> 44) | (t1 << 20)) & 0xfffffc0ffff;

    ctx->r[2] = ((t1 >> 24)             ) & 0x00ffffffc0f;

    /* h (accumulator) = 0 */

    ctx->h[0] = 0;

    ctx->h[1] = 0;

    ctx->h[2] = 0;

    /* save pad for later */

    ctx->pad[0] = U8TO64(key + 16);

    ctx->pad[1] = U8TO64(key + 24);

    ctx->leftover = 0;

    ctx->finished = 0;

#else /* if not 64 bit then use 32 bit */

    /* r &= 0xffffffc0ffffffc0ffffffc0fffffff */

    ctx->r[0] = (U8TO32(key +  0)     ) & 0x3ffffff;

    ctx->r[1] = (U8TO32(key +  3) >> 2) & 0x3ffff03;

    ctx->r[2] = (U8TO32(key +  6) >> 4) & 0x3ffc0ff;

    ctx->r[3] = (U8TO32(key +  9) >> 6) & 0x3f03fff;

    ctx->r[4] = (U8TO32(key + 12) >> 8) & 0x00fffff;

    /* h = 0 */

    ctx->h[0] = 0;

    ctx->h[1] = 0;

    ctx->h[2] = 0;

    ctx->h[3] = 0;

    ctx->h[4] = 0;

    /* save pad for later */

    ctx->pad[0] = U8TO32(key + 16);

    ctx->pad[1] = U8TO32(key + 20);

    ctx->pad[2] = U8TO32(key + 24);

    ctx->pad[3] = U8TO32(key + 28);

    ctx->leftover = 0;

    ctx->finished = 0;

#endif

    return 0;

}

int wc_Poly1305Final(Poly1305* ctx, byte* mac)

{

#ifdef USE_INTEL_SPEEDUP

#elif defined(POLY130564)

    word64 h0,h1,h2,c;

    word64 g0,g1,g2;

    word64 t0,t1;

#else

    word32 h0,h1,h2,h3,h4,c;

    word32 g0,g1,g2,g3,g4;

    word64 f;

    word32 mask;

#endif

    if (ctx == NULL || mac == NULL)

        return BAD_FUNC_ARG;

#ifdef USE_INTEL_SPEEDUP

    SAVE_VECTOR_REGISTERS(return _svr_ret;);

    #ifdef HAVE_INTEL_AVX2

    if (IS_INTEL_AVX2(intel_flags))

        poly1305_final_avx2(ctx, mac);

    else

    #endif

        poly1305_final_avx(ctx, mac);

    RESTORE_VECTOR_REGISTERS();

#elif defined(POLY130564)

    /* process the remaining block */

    if (ctx->leftover) {

        size_t i = ctx->leftover;

        ctx->buffer[i] = 1;

        for (i = i + 1; i < POLY1305_BLOCK_SIZE; i++)

            ctx->buffer[i] = 0;

        ctx->finished = 1;

        poly1305_block(ctx, ctx->buffer);

    }

    /* fully carry h */

    h0 = ctx->h[0];

    h1 = ctx->h[1];

    h2 = ctx->h[2];

                 c = (h1 >> 44); h1 &= 0xfffffffffff;

    h2 += c;     c = (h2 >> 42); h2 &= 0x3ffffffffff;

    h0 += c * 5; c = (h0 >> 44); h0 &= 0xfffffffffff;

    h1 += c;     c = (h1 >> 44); h1 &= 0xfffffffffff;

    h2 += c;     c = (h2 >> 42); h2 &= 0x3ffffffffff;

    h0 += c * 5; c = (h0 >> 44); h0 &= 0xfffffffffff;

    h1 += c;

    /* compute h + -p */

    g0 = h0 + 5; c = (g0 >> 44); g0 &= 0xfffffffffff;

    g1 = h1 + c; c = (g1 >> 44); g1 &= 0xfffffffffff;

    g2 = h2 + c - ((word64)1 << 42);

    /* select h if h < p, or h + -p if h >= p */

    c = (g2 >> ((sizeof(word64) * 8) - 1)) - 1;

    g0 &= c;

    g1 &= c;

    g2 &= c;

    c = ~c;

    h0 = (h0 & c) | g0;

    h1 = (h1 & c) | g1;

    h2 = (h2 & c) | g2;

    /* h = (h + pad) */

    t0 = ctx->pad[0];

    t1 = ctx->pad[1];

    h0 += (( t0                    ) & 0xfffffffffff)    ;

    c = (h0 >> 44); h0 &= 0xfffffffffff;

    h1 += (((t0 >> 44) | (t1 << 20)) & 0xfffffffffff) + c;

    c = (h1 >> 44); h1 &= 0xfffffffffff;

    h2 += (((t1 >> 24)             ) & 0x3ffffffffff) + c;

    h2 &= 0x3ffffffffff;

    /* mac = h % (2^128) */

    h0 = ((h0      ) | (h1 << 44));

    h1 = ((h1 >> 20) | (h2 << 24));

    U64TO8(mac + 0, h0);

    U64TO8(mac + 8, h1);

    /* zero out the state */

    ctx->h[0] = 0;

    ctx->h[1] = 0;

    ctx->h[2] = 0;

    ctx->r[0] = 0;

    ctx->r[1] = 0;

    ctx->r[2] = 0;

    ctx->pad[0] = 0;

    ctx->pad[1] = 0;

#else /* if not 64 bit then use 32 bit */

    /* process the remaining block */

    if (ctx->leftover) {

        size_t i = ctx->leftover;

        ctx->buffer[i++] = 1;

        for (; i < POLY1305_BLOCK_SIZE; i++)

            ctx->buffer[i] = 0;

        ctx->finished = 1;

        poly1305_block(ctx, ctx->buffer);

    }

    /* fully carry h */

    h0 = ctx->h[0];

    h1 = ctx->h[1];

    h2 = ctx->h[2];

    h3 = ctx->h[3];

    h4 = ctx->h[4];

                 c = h1 >> 26; h1 = h1 & 0x3ffffff;

    h2 +=     c; c = h2 >> 26; h2 = h2 & 0x3ffffff;

    h3 +=     c; c = h3 >> 26; h3 = h3 & 0x3ffffff;

    h4 +=     c; c = h4 >> 26; h4 = h4 & 0x3ffffff;

    h0 += c * 5; c = h0 >> 26; h0 = h0 & 0x3ffffff;

    h1 +=     c;

    /* compute h + -p */

    g0 = h0 + 5; c = g0 >> 26; g0 &= 0x3ffffff;

    g1 = h1 + c; c = g1 >> 26; g1 &= 0x3ffffff;

    g2 = h2 + c; c = g2 >> 26; g2 &= 0x3ffffff;

    g3 = h3 + c; c = g3 >> 26; g3 &= 0x3ffffff;

    g4 = h4 + c - ((word32)1 << 26);

    /* select h if h < p, or h + -p if h >= p */

    mask = ((word32)g4 >> ((sizeof(word32) * 8) - 1)) - 1;

    g0 &= mask;

    g1 &= mask;

    g2 &= mask;

    g3 &= mask;

    g4 &= mask;

    mask = ~mask;

    h0 = (h0 & mask) | g0;

    h1 = (h1 & mask) | g1;

    h2 = (h2 & mask) | g2;

    h3 = (h3 & mask) | g3;

    h4 = (h4 & mask) | g4;

    /* h = h % (2^128) */

    h0 = ((h0      ) | (h1 << 26)) & 0xffffffff;

    h1 = ((h1 >>  6) | (h2 << 20)) & 0xffffffff;

    h2 = ((h2 >> 12) | (h3 << 14)) & 0xffffffff;

    h3 = ((h3 >> 18) | (h4 <<  8)) & 0xffffffff;

    /* mac = (h + pad) % (2^128) */

    f = (word64)h0 + ctx->pad[0]            ; h0 = (word32)f;

    f = (word64)h1 + ctx->pad[1] + (f >> 32); h1 = (word32)f;

    f = (word64)h2 + ctx->pad[2] + (f >> 32); h2 = (word32)f;

    f = (word64)h3 + ctx->pad[3] + (f >> 32); h3 = (word32)f;

    U32TO8(mac + 0, h0);

    U32TO8(mac + 4, h1);

    U32TO8(mac + 8, h2);

    U32TO8(mac + 12, h3);

    /* zero out the state */

    ctx->h[0] = 0;

    ctx->h[1] = 0;

    ctx->h[2] = 0;

    ctx->h[3] = 0;

    ctx->h[4] = 0;

    ctx->r[0] = 0;

    ctx->r[1] = 0;

    ctx->r[2] = 0;

    ctx->r[3] = 0;

    ctx->r[4] = 0;

    ctx->pad[0] = 0;

    ctx->pad[1] = 0;

    ctx->pad[2] = 0;

    ctx->pad[3] = 0;

#endif

    return 0;

}

#endif /* !defined(WOLFSSL_ARMASM) || !defined(__aarch64__) */

int wc_Poly1305Update(Poly1305* ctx, const byte* m, word32 bytes)

{

    size_t i;

    if (ctx == NULL || (m == NULL && bytes > 0))

        return BAD_FUNC_ARG;

    if (bytes == 0) {

        /* valid, but do nothing */

        return 0;

    }

#ifdef CHACHA_AEAD_TEST

    word32 k;

    printf("Raw input to poly:\n");

    for (k = 0; k < bytes; k++) {

        printf("%02x", m[k]);

        if ((k+1) % 16 == 0)

            printf("\n");

    }

    printf("\n");

#endif

#ifdef USE_INTEL_SPEEDUP

    #ifdef HAVE_INTEL_AVX2

    if (IS_INTEL_AVX2(intel_flags)) {

        SAVE_VECTOR_REGISTERS(return _svr_ret;);

        /* handle leftover */

        if (ctx->leftover) {

            size_t want = sizeof(ctx->buffer) - ctx->leftover;

            if (want > bytes)

                want = bytes;

            for (i = 0; i < want; i++)

                ctx->buffer[ctx->leftover + i] = m[i];

            bytes -= (word32)want;

            m += want;

            ctx->leftover += want;

            if (ctx->leftover < sizeof(ctx->buffer)) {

                RESTORE_VECTOR_REGISTERS();

                return 0;

            }

            if (!ctx->started)

                poly1305_calc_powers_avx2(ctx);

            poly1305_blocks_avx2(ctx, ctx->buffer, sizeof(ctx->buffer));

            ctx->leftover = 0;

        }

        /* process full blocks */

        if (bytes >= sizeof(ctx->buffer)) {

            size_t want = bytes & ~(sizeof(ctx->buffer) - 1);

            if (!ctx->started)

                poly1305_calc_powers_avx2(ctx);

            poly1305_blocks_avx2(ctx, m, want);

            m += want;

            bytes -= (word32)want;

        }

        /* store leftover */

        if (bytes) {

            for (i = 0; i < bytes; i++)

                ctx->buffer[ctx->leftover + i] = m[i];

            ctx->leftover += bytes;

        }

        RESTORE_VECTOR_REGISTERS();

    }

    else

    #endif

#endif

    {

        /* handle leftover */

        if (ctx->leftover) {

            size_t want = (POLY1305_BLOCK_SIZE - ctx->leftover);

            if (want > bytes)

                want = bytes;

            for (i = 0; i < want; i++)

                ctx->buffer[ctx->leftover + i] = m[i];

            bytes -= (word32)want;

            m += want;

            ctx->leftover += want;

            if (ctx->leftover < POLY1305_BLOCK_SIZE)

                return 0;

            poly1305_block(ctx, ctx->buffer);

            ctx->leftover = 0;

        }

        /* process full blocks */

        if (bytes >= POLY1305_BLOCK_SIZE) {

            size_t want = (bytes & ~(POLY1305_BLOCK_SIZE - 1));

#if !defined(WOLFSSL_ARMASM) || !defined(__aarch64__)

            int ret;

            ret = poly1305_blocks(ctx, m, want);

            if (ret != 0)

                return ret;

#else

            poly1305_blocks(ctx, m, want);

#endif

            m += want;

            bytes -= (word32)want;

        }

        /* store leftover */

        if (bytes) {

            for (i = 0; i < bytes; i++)

                ctx->buffer[ctx->leftover + i] = m[i];

            ctx->leftover += bytes;

        }

    }

    return 0;

}

/*  Takes a Poly1305 struct that has a key loaded and pads the provided length

    ctx        : Initialized Poly1305 struct to use

    lenToPad   : Current number of bytes updated that needs padding to 16

 */

int wc_Poly1305_Pad(Poly1305* ctx, word32 lenToPad)

{

    int ret = 0;

    word32 paddingLen;

    byte padding[WC_POLY1305_PAD_SZ - 1];

    if (ctx == NULL) {

        return BAD_FUNC_ARG;

    }

    if (lenToPad == 0) {

        return 0; /* nothing needs to be done */

    }

    XMEMSET(padding, 0, sizeof(padding));

    /* Pad length to 16 bytes */

    paddingLen = (-(int)lenToPad) & (WC_POLY1305_PAD_SZ - 1);

    if ((paddingLen > 0) && (paddingLen < WC_POLY1305_PAD_SZ)) {

        ret = wc_Poly1305Update(ctx, padding, paddingLen);

    }

    return ret;

}

/*  Takes a Poly1305 struct that has a key loaded and adds the AEAD length

    encoding in 64-bit little endian

    aadSz      : Size of the additional authentication data

    dataSz     : Size of the plaintext or ciphertext

 */

int wc_Poly1305_EncodeSizes(Poly1305* ctx, word32 aadSz, word32 dataSz)

{

    int ret;

    byte little64[16]; /* sizeof(word64) * 2 */

    if (ctx == NULL) {

        return BAD_FUNC_ARG;

    }

    XMEMSET(little64, 0, sizeof(little64));

    /* size of additional data and input data as little endian 64 bit types */

    u32tole64(aadSz,  little64);

    u32tole64(dataSz, little64 + 8);

    ret = wc_Poly1305Update(ctx, little64, sizeof(little64));

    return ret;

}

#ifdef WORD64_AVAILABLE

int wc_Poly1305_EncodeSizes64(Poly1305* ctx, word64 aadSz, word64 dataSz)

{

    int ret;

    word64 little64[2];

    if (ctx == NULL) {

        return BAD_FUNC_ARG;

    }

#ifdef BIG_ENDIAN_ORDER

    little64[0] = ByteReverseWord64(aadSz);

    little64[1] = ByteReverseWord64(dataSz);

#else

    little64[0] = aadSz;

    little64[1] = dataSz;

#endif

    ret = wc_Poly1305Update(ctx, (byte *)little64, sizeof(little64));

    return ret;

}

#endif

/*  Takes in an initialized Poly1305 struct that has a key loaded and creates

    a MAC (tag) using recent TLS AEAD padding scheme.

    ctx        : Initialized Poly1305 struct to use

    additional : Additional data to use

    addSz      : Size of additional buffer

    input      : Input buffer to create tag from

    sz         : Size of input buffer

    tag        : Buffer to hold created tag

    tagSz      : Size of input tag buffer (must be at least

                 WC_POLY1305_MAC_SZ(16))

 */

int wc_Poly1305_MAC(Poly1305* ctx, const byte* additional, word32 addSz,

                    const byte* input, word32 sz, byte* tag, word32 tagSz)

{

    int ret;

    /* sanity check on arguments */

    if (ctx == NULL || input == NULL || tag == NULL ||

                                                   tagSz < WC_POLY1305_MAC_SZ) {

        return BAD_FUNC_ARG;

    }

    /* additional allowed to be 0 */

    if (addSz > 0) {

        if (additional == NULL)

            return BAD_FUNC_ARG;

        /* additional data plus padding */

        if ((ret = wc_Poly1305Update(ctx, additional, addSz)) != 0) {

            return ret;

        }

        /* pad additional data */

        if ((ret = wc_Poly1305_Pad(ctx, addSz)) != 0) {

            return ret;

        }

    }

    /* input plus padding */

    if ((ret = wc_Poly1305Update(ctx, input, sz)) != 0) {

        return ret;

    }

    /* pad input data */

    if ((ret = wc_Poly1305_Pad(ctx, sz)) != 0) {

        return ret;

    }

    /* encode size of AAD and input data as little endian 64 bit types */

    if ((ret = wc_Poly1305_EncodeSizes(ctx, addSz, sz)) != 0) {

        return ret;

    }

    /* Finalize the auth tag */

    ret = wc_Poly1305Final(ctx, tag);

    return ret;

}

#endif /* HAVE_POLY1305 */