text: /*
   * MD4 hash implementation
   *
   * This software may be distributed under the terms of BSD license.
   */
  
  #include "crypto/includes.h"
  #include "crypto/common.h"
  #include "crypto/crypto.h"
  
  #define MD4_BLOCK_LENGTH    64
  #define MD4_DIGEST_LENGTH    16
  
  typedef struct MD4Context {
      u32 state[4];
      u64 count;
      u8 buffer[MD4_BLOCK_LENGTH];
  } MD4_CTX;
  
  static void MD4Init(MD4_CTX *ctx);
  static void MD4Update(MD4_CTX *ctx, const unsigned char *input, size_t len);
  static void MD4Final(unsigned char digest[MD4_DIGEST_LENGTH], MD4_CTX *ctx);
  
  int md4_vector(size_t num_elem, const u8 *addr[], const size_t *len, u8 *mac)
  {
      MD4_CTX ctx;
      size_t i;
  
      MD4Init(&ctx);
      for (i = 0; i < num_elem; i++)
          MD4Update(&ctx, addr[i], len[i]);
      MD4Final(mac, &ctx);
      return 0;
  }
  
  #define MD4_DIGEST_STRING_LENGTH    (MD4_DIGEST_LENGTH * 2 + 1)
  
  static void MD4Transform(u32 state[4], const u8 block[MD4_BLOCK_LENGTH]);
  
  #define PUT_64BIT_LE(cp, value) do {    \
      (cp)[7] = (value) >> 56;    \
      (cp)[6] = (value) >> 48;    \
      (cp)[5] = (value) >> 40;    \
      (cp)[4] = (value) >> 32;    \
      (cp)[3] = (value) >> 24;    \
      (cp)[2] = (value) >> 16;    \
      (cp)[1] = (value) >> 8;        \
      (cp)[0] = (value); } while (0)
  
  #define PUT_32BIT_LE(cp, value) do {    \
      (cp)[3] = (value) >> 24;    \
      (cp)[2] = (value) >> 16;    \
      (cp)[1] = (value) >> 8;        \
      (cp)[0] = (value); } while (0)
  
  static u8 PADDING[MD4_BLOCK_LENGTH] = {
      0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
      0,    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
      0,    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
      0,    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
  };
  
  static void MD4Init(MD4_CTX *ctx)
  {
      ctx->count = 0;
      ctx->state[0] = 0x67452301;
      ctx->state[1] = 0xefcdab89;
      ctx->state[2] = 0x98badcfe;
      ctx->state[3] = 0x10325476;
  }
  
  static void MD4Update(MD4_CTX *ctx, const unsigned char *input, size_t len)
  {
      size_t have, need;
  
      have = (size_t)((ctx->count >> 3) & (MD4_BLOCK_LENGTH - 1));
      need = MD4_BLOCK_LENGTH - have;
  
      ctx->count += (u64)len << 3;
  
      if (len >= need) {
          if (have != 0) {
              os_memcpy(ctx->buffer + have, input, need);
              MD4Transform(ctx->state, ctx->buffer);
              input += need;
              len -= need;
              have = 0;
          }
  
          while (len >= MD4_BLOCK_LENGTH) {
              MD4Transform(ctx->state, input);
              input += MD4_BLOCK_LENGTH;
              len -= MD4_BLOCK_LENGTH;
          }
      }
  
      if (len != 0)
          os_memcpy(ctx->buffer + have, input, len);
  }
  
  static void MD4Pad(MD4_CTX *ctx)
  {
      u8 count[8];
      size_t padlen;
  
      PUT_64BIT_LE(count, ctx->count);
  
      padlen = MD4_BLOCK_LENGTH -
          ((ctx->count >> 3) & (MD4_BLOCK_LENGTH - 1));
      if (padlen < 1 + 8)
          padlen += MD4_BLOCK_LENGTH;
      MD4Update(ctx, PADDING, padlen - 8);
      MD4Update(ctx, count, 8);
  }
  
  static void MD4Final(unsigned char digest[MD4_DIGEST_LENGTH], MD4_CTX *ctx)
  {
      int i;
  
      MD4Pad(ctx);
      if (digest != NULL) {
          for (i = 0; i < 4; i ++)
              PUT_32BIT_LE(digest + i * 4, ctx->state[i]);
          os_memset(ctx, 0, sizeof(*ctx));
      }
  }
  
  #define F1(x, y, z)    (z ^ (x & (y ^ z)))
  #define F2(x, y, z)    ((x & y) | (x & z) | (y & z))
  #define F3(x, y, z)    (x ^ y ^ z)
  
  #define MD4SETP(f, w, x, y, z, data, s)    \
      ( w += f(x, y, z) + data, w = w<<s | w>>(32-s) )
  
  static void MD4Transform(u32 state[4], const u8 block[MD4_BLOCK_LENGTH])
  {
      u32 a, b, c, d, in[MD4_BLOCK_LENGTH / 4];
  
      os_memcpy(in, block, sizeof(in));
  
      a = state[0];
      b = state[1];
      c = state[2];
      d = state[3];
  
      MD4SETP(F1, a, b, c, d, in[ 0], 3);
      MD4SETP(F1, d, a, b, c, in[ 1], 7);
      MD4SETP(F1, c, d, a, b, in[ 2], 11);
      MD4SETP(F1, b, c, d, a, in[ 3], 19);
      MD4SETP(F1, a, b, c, d, in[ 4], 3);
      MD4SETP(F1, d, a, b, c, in[ 5], 7);
      MD4SETP(F1, c, d, a, b, in[ 6], 11);
      MD4SETP(F1, b, c, d, a, in[ 7], 19);
      MD4SETP(F1, a, b, c, d, in[ 8], 3);
      MD4SETP(F1, d, a, b, c, in[ 9], 7);
      MD4SETP(F1, c, d, a, b, in[10], 11);
      MD4SETP(F1, b, c, d, a, in[11], 19);
      MD4SETP(F1, a, b, c, d, in[12], 3);
      MD4SETP(F1, d, a, b, c, in[13], 7);
      MD4SETP(F1, c, d, a, b, in[14], 11);
      MD4SETP(F1, b, c, d, a, in[15], 19);
  
      MD4SETP(F2, a, b, c, d, in[ 0] + 0x5a827999, 3);
      MD4SETP(F2, d, a, b, c, in[ 4] + 0x5a827999, 5);
      MD4SETP(F2, c, d, a, b, in[ 8] + 0x5a827999, 9);
      MD4SETP(F2, b, c, d, a, in[12] + 0x5a827999, 13);
      MD4SETP(F2, a, b, c, d, in[ 1] + 0x5a827999, 3);
      MD4SETP(F2, d, a, b, c, in[ 5] + 0x5a827999, 5);
      MD4SETP(F2, c, d, a, b, in[ 9] + 0x5a827999, 9);
      MD4SETP(F2, b, c, d, a, in[13] + 0x5a827999, 13);
      MD4SETP(F2, a, b, c, d, in[ 2] + 0x5a827999, 3);
      MD4SETP(F2, d, a, b, c, in[ 6] + 0x5a827999, 5);
      MD4SETP(F2, c, d, a, b, in[10] + 0x5a827999, 9);
      MD4SETP(F2, b, c, d, a, in[14] + 0x5a827999, 13);
      MD4SETP(F2, a, b, c, d, in[ 3] + 0x5a827999, 3);
      MD4SETP(F2, d, a, b, c, in[ 7] + 0x5a827999, 5);
      MD4SETP(F2, c, d, a, b, in[11] + 0x5a827999, 9);
      MD4SETP(F2, b, c, d, a, in[15] + 0x5a827999, 13);
  
      MD4SETP(F3, a, b, c, d, in[ 0] + 0x6ed9eba1,  3);
      MD4SETP(F3, d, a, b, c, in[ 8] + 0x6ed9eba1,  9);
      MD4SETP(F3, c, d, a, b, in[ 4] + 0x6ed9eba1, 11);
      MD4SETP(F3, b, c, d, a, in[12] + 0x6ed9eba1, 15);
      MD4SETP(F3, a, b, c, d, in[ 2] + 0x6ed9eba1,  3);
      MD4SETP(F3, d, a, b, c, in[10] + 0x6ed9eba1,  9);
      MD4SETP(F3, c, d, a, b, in[ 6] + 0x6ed9eba1, 11);
      MD4SETP(F3, b, c, d, a, in[14] + 0x6ed9eba1, 15);
      MD4SETP(F3, a, b, c, d, in[ 1] + 0x6ed9eba1,  3);
      MD4SETP(F3, d, a, b, c, in[ 9] + 0x6ed9eba1,  9);
      MD4SETP(F3, c, d, a, b, in[ 5] + 0x6ed9eba1, 11);
      MD4SETP(F3, b, c, d, a, in[13] + 0x6ed9eba1, 15);
      MD4SETP(F3, a, b, c, d, in[ 3] + 0x6ed9eba1,  3);
      MD4SETP(F3, d, a, b, c, in[11] + 0x6ed9eba1,  9);
      MD4SETP(F3, c, d, a, b, in[ 7] + 0x6ed9eba1, 11);
      MD4SETP(F3, b, c, d, a, in[15] + 0x6ed9eba1, 15);
  
      state[0] += a;
      state[1] += b;
      state[2] += c;
      state[3] += d;
  }
  