text: /* -*- Mode: C; tab-width: 4 -*-
   *
   * Copyright (c) 2002-2011 Apple Inc. All rights reserved.
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  #ifdef __cplusplus
  extern "C" {
  #endif
  
  #include "mDNSEmbeddedAPI.h"
  #include "DNSCommon.h"
  
  // Disable certain benign warnings with Microsoft compilers
  #if (defined(_MSC_VER))
  // Disable "conditional expression is constant" warning for debug macros.
  // Otherwise, this generates warnings for the perfectly natural construct "while(1)"
  // If someone knows a variant way of writing "while(1)" that doesn't generate warning messages, please let us know
      #pragma warning(disable:4127)
  #endif
  
  
  // ***************************************************************************
  #if COMPILER_LIKES_PRAGMA_MARK
  #pragma mark - Byte Swapping Functions
  #endif
  
  mDNSlocal mDNSu16 NToH16(mDNSu8 * bytes)
  {
      return (mDNSu16)((mDNSu16)bytes[0] << 8 | (mDNSu16)bytes[1]);
  }
  
  mDNSlocal mDNSu32 NToH32(mDNSu8 * bytes)
  {
      return (mDNSu32)((mDNSu32) bytes[0] << 24 | (mDNSu32) bytes[1] << 16 | (mDNSu32) bytes[2] << 8 | (mDNSu32)bytes[3]);
  }
  
  // ***************************************************************************
  #if COMPILER_LIKES_PRAGMA_MARK
  #pragma mark - MD5 Hash Functions
  #endif
  
  
  /* The source for the has is derived CommonCrypto files CommonDigest.h, md32_common.h, md5_locl.h, md5_locl.h, and openssl/md5.h.
   * The following changes have been made to the original sources:
   *    replaced CC_LONG w/ mDNSu32
   *    replaced CC_MD5* with MD5*
   *    replaced CC_LONG w/ mDNSu32, removed conditional #defines from md5.h
   *    removed extern decls for MD5_Init/Update/Final from CommonDigest.h
   *    removed APPLE_COMMON_DIGEST specific #defines from md5_locl.h
   *
   * Note: machine archetecure specific conditionals from the original sources are turned off, but are left in the code
   * to aid in platform-specific optimizations and debugging.
   * Sources originally distributed under the following license headers:
   * CommonDigest.h - APSL
   *
   * md32_Common.h
   * ====================================================================
   * Copyright (c) 1999-2002 The OpenSSL Project.  All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   *
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in
   *    the documentation and/or other materials provided with the
   *    distribution.
   *
   * 3. All advertising materials mentioning features or use of this
   *    software must display the following acknowledgment:
   *    "This product includes software developed by the OpenSSL Project
   *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
   *
   * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
   *    endorse or promote products derived from this software without
   *    prior written permission. For written permission, please contact
   *    licensing@OpenSSL.org.
   *
   * 5. Products derived from this software may not be called "OpenSSL"
   *    nor may "OpenSSL" appear in their names without prior written
   *    permission of the OpenSSL Project.
   *
   * 6. Redistributions of any form whatsoever must retain the following
   *    acknowledgment:
   *    "This product includes software developed by the OpenSSL Project
   *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
   *
   * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
   * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
   * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
   * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
   * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
   * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
   * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
   * OF THE POSSIBILITY OF SUCH DAMAGE.
   *
   *
   * md5_dgst.c, md5_locl.h
   * ====================================================================
   *
   * This product includes cryptographic software written by Eric Young
   * (eay@cryptsoft.com).  This product includes software written by Tim
   * Hudson (tjh@cryptsoft.com).
   *
   * Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
   * All rights reserved.
   *
   * This package is an SSL implementation written
   * by Eric Young (eay@cryptsoft.com).
   * The implementation was written so as to conform with Netscapes SSL.
   *
   * This library is free for commercial and non-commercial use as long as
   * the following conditions are aheared to.  The following conditions
   * apply to all code found in this distribution, be it the RC4, RSA,
   * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
   * included with this distribution is covered by the same copyright terms
   * except that the holder is Tim Hudson (tjh@cryptsoft.com).
   *
   * Copyright remains Eric Young's, and as such any Copyright notices in
   * the code are not to be removed.
   * If this package is used in a product, Eric Young should be given attribution
   * as the author of the parts of the library used.
   * This can be in the form of a textual message at program startup or
   * in documentation (online or textual) provided with the package.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   * 3. All advertising materials mentioning features or use of this software
   *    must display the following acknowledgement:
   *    "This product includes cryptographic software written by
   *     Eric Young (eay@cryptsoft.com)"
   *    The word 'cryptographic' can be left out if the rouines from the library
   *    being used are not cryptographic related :-).
   * 4. If you include any Windows specific code (or a derivative thereof) from
   *    the apps directory (application code) you must include an acknowledgement:
   *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
   *
   * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   *
   * The licence and distribution terms for any publically available version or
   * derivative of this code cannot be changed.  i.e. this code cannot simply be
   * copied and put under another distribution licence
   * [including the GNU Public Licence.]
   *
   */
  
  //from CommonDigest.h
  
  
  
  // from openssl/md5.h
  
  #define MD5_CBLOCK  64
  #define MD5_LBLOCK  (MD5_CBLOCK/4)
  #define MD5_DIGEST_LENGTH 16
  
  void MD5_Transform(MD5_CTX *c, const unsigned char *b);
  
  // From md5_locl.h
  
  #ifndef MD5_LONG_LOG2
  #define MD5_LONG_LOG2 2 /* default to 32 bits */
  #endif
  
  #ifdef MD5_ASM
  # if defined(__i386) || defined(__i386__) || defined(_M_IX86) || defined(__INTEL__)
  #  define md5_block_host_order md5_block_asm_host_order
  # elif defined(__sparc) && defined(OPENSSL_SYS_ULTRASPARC)
  void md5_block_asm_data_order_aligned (MD5_CTX *c, const mDNSu32 *p,int num);
  #  define HASH_BLOCK_DATA_ORDER_ALIGNED md5_block_asm_data_order_aligned
  # endif
  #endif
  
  void md5_block_host_order (MD5_CTX *c, const void *p,int num);
  void md5_block_data_order (MD5_CTX *c, const void *p,int num);
  
  #if defined(__i386) || defined(__i386__) || defined(_M_IX86) || defined(__INTEL__)
  /*
   * *_block_host_order is expected to handle aligned data while
   * *_block_data_order - unaligned. As algorithm and host (x86)
   * are in this case of the same "endianness" these two are
   * otherwise indistinguishable. But normally you don't want to
   * call the same function because unaligned access in places
   * where alignment is expected is usually a "Bad Thing". Indeed,
   * on RISCs you get punished with BUS ERROR signal or *severe*
   * performance degradation. Intel CPUs are in turn perfectly
   * capable of loading unaligned data without such drastic side
   * effect. Yes, they say it's slower than aligned load, but no
   * exception is generated and therefore performance degradation
   * is *incomparable* with RISCs. What we should weight here is
   * costs of unaligned access against costs of aligning data.
   * According to my measurements allowing unaligned access results
   * in ~9% performance improvement on Pentium II operating at
   * 266MHz. I won't be surprised if the difference will be higher
   * on faster systems:-)
   *
   *				<appro@fy.chalmers.se>
   */
  #define md5_block_data_order md5_block_host_order
  #endif
  
  #define DATA_ORDER_IS_LITTLE_ENDIAN
  
  #define HASH_LONG       mDNSu32
  #define HASH_LONG_LOG2  MD5_LONG_LOG2
  #define HASH_CTX        MD5_CTX
  #define HASH_CBLOCK     MD5_CBLOCK
  #define HASH_LBLOCK     MD5_LBLOCK
  
  #define HASH_UPDATE     MD5_Update
  #define HASH_TRANSFORM  MD5_Transform
  #define HASH_FINAL      MD5_Final
  
  #define HASH_MAKE_STRING(c,s)   do {    \
          unsigned long ll;       \
          ll=(c)->A; HOST_l2c(ll,(s));    \
          ll=(c)->B; HOST_l2c(ll,(s));    \
          ll=(c)->C; HOST_l2c(ll,(s));    \
          ll=(c)->D; HOST_l2c(ll,(s));    \
  } while (0)
  #define HASH_BLOCK_HOST_ORDER   md5_block_host_order
  #if !defined(L_ENDIAN) || defined(md5_block_data_order)
  #define HASH_BLOCK_DATA_ORDER   md5_block_data_order
  /*
   * Little-endians (Intel and Alpha) feel better without this.
   * It looks like memcpy does better job than generic
   * md5_block_data_order on copying-n-aligning input data.
   * But frankly speaking I didn't expect such result on Alpha.
   * On the other hand I've got this with egcs-1.0.2 and if
   * program is compiled with another (better?) compiler it
   * might turn out other way around.
   *
   *				<appro@fy.chalmers.se>
   */
  #endif
  
  
  // from md32_common.h
  
  /*
   * This is a generic 32 bit "collector" for message digest algorithms.
   * Whenever needed it collects input character stream into chunks of
   * 32 bit values and invokes a block function that performs actual hash
   * calculations.
   *
   * Porting guide.
   *
   * Obligatory macros:
   *
   * DATA_ORDER_IS_BIG_ENDIAN or DATA_ORDER_IS_LITTLE_ENDIAN
   *	this macro defines byte order of input stream.
   * HASH_CBLOCK
   *	size of a unit chunk HASH_BLOCK operates on.
   * HASH_LONG
   *	has to be at lest 32 bit wide, if it's wider, then
   *	HASH_LONG_LOG2 *has to* be defined along
   * HASH_CTX
   *	context structure that at least contains following
   *	members:
   *		typedef struct {
   *			...
   *			HASH_LONG	Nl,Nh;
   *			HASH_LONG	data[HASH_LBLOCK];
   *			int		num;
   *			...
   *			} HASH_CTX;
   * HASH_UPDATE
   *	name of "Update" function, implemented here.
   * HASH_TRANSFORM
   *	name of "Transform" function, implemented here.
   * HASH_FINAL
   *	name of "Final" function, implemented here.
   * HASH_BLOCK_HOST_ORDER
   *	name of "block" function treating *aligned* input message
   *	in host byte order, implemented externally.
   * HASH_BLOCK_DATA_ORDER
   *	name of "block" function treating *unaligned* input message
   *	in original (data) byte order, implemented externally (it
   *	actually is optional if data and host are of the same
   *	"endianess").
   * HASH_MAKE_STRING
   *	macro convering context variables to an ASCII hash string.
   *
   * Optional macros:
   *
   * B_ENDIAN or L_ENDIAN
   *	defines host byte-order.
   * HASH_LONG_LOG2
   *	defaults to 2 if not states otherwise.
   * HASH_LBLOCK
   *	assumed to be HASH_CBLOCK/4 if not stated otherwise.
   * HASH_BLOCK_DATA_ORDER_ALIGNED
   *	alternative "block" function capable of treating
   *	aligned input message in original (data) order,
   *	implemented externally.
   *
   * MD5 example:
   *
   *	#define DATA_ORDER_IS_LITTLE_ENDIAN
   *
   *	#define HASH_LONG		mDNSu32
   *	#define HASH_LONG_LOG2	mDNSu32_LOG2
   *	#define HASH_CTX		MD5_CTX
   *	#define HASH_CBLOCK		MD5_CBLOCK
   *	#define HASH_LBLOCK		MD5_LBLOCK
   *	#define HASH_UPDATE		MD5_Update
   *	#define HASH_TRANSFORM		MD5_Transform
   *	#define HASH_FINAL		MD5_Final
   *	#define HASH_BLOCK_HOST_ORDER	md5_block_host_order
   *	#define HASH_BLOCK_DATA_ORDER	md5_block_data_order
   *
   *					<appro@fy.chalmers.se>
   */
  
  #if !defined(DATA_ORDER_IS_BIG_ENDIAN) && !defined(DATA_ORDER_IS_LITTLE_ENDIAN)
  #error "DATA_ORDER must be defined!"
  #endif
  
  #ifndef HASH_CBLOCK
  #error "HASH_CBLOCK must be defined!"
  #endif
  #ifndef HASH_LONG
  #error "HASH_LONG must be defined!"
  #endif
  #ifndef HASH_CTX
  #error "HASH_CTX must be defined!"
  #endif
  
  #ifndef HASH_UPDATE
  #error "HASH_UPDATE must be defined!"
  #endif
  #ifndef HASH_TRANSFORM
  #error "HASH_TRANSFORM must be defined!"
  #endif
  #ifndef HASH_FINAL
  #error "HASH_FINAL must be defined!"
  #endif
  
  #ifndef HASH_BLOCK_HOST_ORDER
  #error "HASH_BLOCK_HOST_ORDER must be defined!"
  #endif
  
  #if 0
  /*
   * Moved below as it's required only if HASH_BLOCK_DATA_ORDER_ALIGNED
   * isn't defined.
   */
  #ifndef HASH_BLOCK_DATA_ORDER
  #error "HASH_BLOCK_DATA_ORDER must be defined!"
  #endif
  #endif
  
  #ifndef HASH_LBLOCK
  #define HASH_LBLOCK (HASH_CBLOCK/4)
  #endif
  
  #ifndef HASH_LONG_LOG2
  #define HASH_LONG_LOG2  2
  #endif
  
  /*
   * Engage compiler specific rotate intrinsic function if available.
   */
  #undef ROTATE
  #ifndef PEDANTIC
  # if 0 /* defined(_MSC_VER) */
  #  define ROTATE(a,n)   _lrotl(a,n)
  # elif defined(__MWERKS__)
  #  if defined(__POWERPC__)
  #   define ROTATE(a,n)  (unsigned MD32_REG_T)__rlwinm((int)a,n,0,31)
  #  elif defined(__MC68K__)
  /* Motorola specific tweak. <appro@fy.chalmers.se> */
  #   define ROTATE(a,n)  (n<24 ? __rol(a,n) : __ror(a,32-n))
  #  else
  #   define ROTATE(a,n)  __rol(a,n)
  #  endif
  # elif defined(__GNUC__) && __GNUC__>=2 && !defined(OPENSSL_NO_ASM) && !defined(OPENSSL_NO_INLINE_ASM)
  /*
   * Some GNU C inline assembler templates. Note that these are
   * rotates by *constant* number of bits! But that's exactly
   * what we need here...
   *
   *                  <appro@fy.chalmers.se>
   */
  /*
   * LLVM is more strict about compatibility of types between input & output constraints,
   * but we want these to be rotations of 32 bits, not 64, so we explicitly drop the
   * most significant bytes by casting to an unsigned int.
   */
  #  if defined(__i386) || defined(__i386__) || defined(__x86_64) || defined(__x86_64__)
  #   define ROTATE(a,n)  ({ register unsigned int ret;   \
                             asm (           \
                                 "roll %1,%0"        \
                                 : "=r" (ret)     \
                                 : "I" (n), "0" ((unsigned int)a)  \
                                 : "cc");        \
                             ret;             \
                           })
  #  elif defined(__powerpc) || defined(__ppc)
  #   define ROTATE(a,n)  ({ register unsigned int ret;   \
                             asm (           \
                                 "rlwinm %0,%1,%2,0,31"  \
                                 : "=r" (ret)     \
                                 : "r" (a), "I" (n));  \
                             ret;             \
                           })
  #  endif
  # endif
  
  /*
   * Engage compiler specific "fetch in reverse byte order"
   * intrinsic function if available.
   */
  # if defined(__GNUC__) && __GNUC__>=2 && !defined(OPENSSL_NO_ASM) && !defined(OPENSSL_NO_INLINE_ASM)
  /* some GNU C inline assembler templates by <appro@fy.chalmers.se> */
  #  if (defined(__i386) || defined(__i386__) || defined(__x86_64) || defined(__x86_64__)) && !defined(I386_ONLY)
  #   define BE_FETCH32(a)    ({ register unsigned int l=(a); \
                                 asm (           \
                                     "bswapl %0"     \
                                     : "=r" (l) : "0" (l));    \
                                 l;                \
                               })
  #  elif defined(__powerpc)
  #   define LE_FETCH32(a)    ({ register unsigned int l; \
                                 asm (           \
                                     "lwbrx %0,0,%1"     \
                                     : "=r" (l)       \
                                     : "r" (a));      \
                                 l;               \
                               })
  
  #  elif defined(__sparc) && defined(OPENSSL_SYS_ULTRASPARC)
  #  define LE_FETCH32(a) ({ register unsigned int l;     \
                             asm (               \
                                 "lda [%1]#ASI_PRIMARY_LITTLE,%0" \
                                 : "=r" (l)           \
                                 : "r" (a));          \
                             l;                   \
                           })
  #  endif
  # endif
  #endif /* PEDANTIC */
  
  #if HASH_LONG_LOG2==2   /* Engage only if sizeof(HASH_LONG)== 4 */
  /* A nice byte order reversal from Wei Dai <weidai@eskimo.com> */
  #ifdef ROTATE
  /* 5 instructions with rotate instruction, else 9 */
  #define REVERSE_FETCH32(a,l)    (                   \
          l=*(const HASH_LONG *)(a),              \
          ((ROTATE(l,8)&0x00FF00FF)|(ROTATE((l&0x00FF00FF),24)))  \
          )
  #else
  /* 6 instructions with rotate instruction, else 8 */
  #define REVERSE_FETCH32(a,l)    (               \
          l=*(const HASH_LONG *)(a),          \
          l=(((l>>8)&0x00FF00FF)|((l&0x00FF00FF)<<8)),    \
          ROTATE(l,16)                    \
          )
  /*
   * Originally the middle line started with l=(((l&0xFF00FF00)>>8)|...
   * It's rewritten as above for two reasons:
   *	- RISCs aren't good at long constants and have to explicitely
   *	  compose 'em with several (well, usually 2) instructions in a
   *	  register before performing the actual operation and (as you
   *	  already realized:-) having same constant should inspire the
   *	  compiler to permanently allocate the only register for it;
   *	- most modern CPUs have two ALUs, but usually only one has
   *	  circuitry for shifts:-( this minor tweak inspires compiler
   *	  to schedule shift instructions in a better way...
   *
   *				<appro@fy.chalmers.se>
   */
  #endif
  #endif
  
  #ifndef ROTATE
  #define ROTATE(a,n)     (((a)<<(n))|(((a)&0xffffffff)>>(32-(n))))
  #endif
  
  /*
   * Make some obvious choices. E.g., HASH_BLOCK_DATA_ORDER_ALIGNED
   * and HASH_BLOCK_HOST_ORDER ought to be the same if input data
   * and host are of the same "endianess". It's possible to mask
   * this with blank #define HASH_BLOCK_DATA_ORDER though...
   *
   *				<appro@fy.chalmers.se>
   */
  #if defined(B_ENDIAN)
  #  if defined(DATA_ORDER_IS_BIG_ENDIAN)
  #    if !defined(HASH_BLOCK_DATA_ORDER_ALIGNED) && HASH_LONG_LOG2==2
  #      define HASH_BLOCK_DATA_ORDER_ALIGNED HASH_BLOCK_HOST_ORDER
  #    endif
  #  elif defined(DATA_ORDER_IS_LITTLE_ENDIAN)
  #    ifndef HOST_FETCH32
  #      ifdef LE_FETCH32
  #        define HOST_FETCH32(p,l)   LE_FETCH32(p)
  #      elif defined(REVERSE_FETCH32)
  #        define HOST_FETCH32(p,l)   REVERSE_FETCH32(p,l)
  #      endif
  #    endif
  #  endif
  #elif defined(L_ENDIAN)
  #  if defined(DATA_ORDER_IS_LITTLE_ENDIAN)
  #    if !defined(HASH_BLOCK_DATA_ORDER_ALIGNED) && HASH_LONG_LOG2==2
  #      define HASH_BLOCK_DATA_ORDER_ALIGNED HASH_BLOCK_HOST_ORDER
  #    endif
  #  elif defined(DATA_ORDER_IS_BIG_ENDIAN)
  #    ifndef HOST_FETCH32
  #      ifdef BE_FETCH32
  #        define HOST_FETCH32(p,l)   BE_FETCH32(p)
  #      elif defined(REVERSE_FETCH32)
  #        define HOST_FETCH32(p,l)   REVERSE_FETCH32(p,l)
  #      endif
  #    endif
  #  endif
  #endif
  
  #if !defined(HASH_BLOCK_DATA_ORDER_ALIGNED)
  #ifndef HASH_BLOCK_DATA_ORDER
  #error "HASH_BLOCK_DATA_ORDER must be defined!"
  #endif
  #endif
  
  // None of the invocations of the following macros actually use the result,
  // so cast them to void to avoid any compiler warnings/errors about not using
  // the result (e.g. when using clang).
  // If the resultant values need to be used at some point, these must be changed.
  #define HOST_c2l(c,l) ((void)_HOST_c2l(c,l))
  #define HOST_l2c(l,c) ((void)_HOST_l2c(l,c))
  
  #if defined(DATA_ORDER_IS_BIG_ENDIAN)
  
  #define _HOST_c2l(c,l)  (l =(((unsigned long)(*((c)++)))<<24),      \
                           l|=(((unsigned long)(*((c)++)))<<16),      \
                           l|=(((unsigned long)(*((c)++)))<< 8),      \
                           l|=(((unsigned long)(*((c)++)))    ),      \
                           l)
  #define HOST_p_c2l(c,l,n)   {                   \
          switch (n) {                    \
          case 0: l =((unsigned long)(*((c)++)))<<24; \
          case 1: l|=((unsigned long)(*((c)++)))<<16; \
          case 2: l|=((unsigned long)(*((c)++)))<< 8; \
          case 3: l|=((unsigned long)(*((c)++)));     \
          } }
  #define HOST_p_c2l_p(c,l,sc,len) {                  \
          switch (sc) {                   \
          case 0: l =((unsigned long)(*((c)++)))<<24; \
              if (--len == 0) break;                                                 \
          case 1: l|=((unsigned long)(*((c)++)))<<16; \
              if (--len == 0) break;                                                 \
          case 2: l|=((unsigned long)(*((c)++)))<< 8; \
          } }
  /* NOTE the pointer is not incremented at the end of this */
  #define HOST_c2l_p(c,l,n)   {                   \
          l=0; (c)+=n;                    \
          switch (n) {                    \
          case 3: l =((unsigned long)(*(--(c))))<< 8; \
          case 2: l|=((unsigned long)(*(--(c))))<<16; \
          case 1: l|=((unsigned long)(*(--(c))))<<24; \
          } }
  #define _HOST_l2c(l,c)  (*((c)++)=(unsigned char)(((l)>>24)&0xff),  \
                           *((c)++)=(unsigned char)(((l)>>16)&0xff),  \
                           *((c)++)=(unsigned char)(((l)>> 8)&0xff),  \
                           *((c)++)=(unsigned char)(((l)    )&0xff),  \
                           l)
  
  #elif defined(DATA_ORDER_IS_LITTLE_ENDIAN)
  
  #define _HOST_c2l(c,l)  (l =(((unsigned long)(*((c)++)))    ),      \
                           l|=(((unsigned long)(*((c)++)))<< 8),      \
                           l|=(((unsigned long)(*((c)++)))<<16),      \
                           l|=(((unsigned long)(*((c)++)))<<24),      \
                           l)
  #define HOST_p_c2l(c,l,n)   {                   \
          switch (n) {                    \
          case 0: l =((unsigned long)(*((c)++)));     \
          case 1: l|=((unsigned long)(*((c)++)))<< 8; \
          case 2: l|=((unsigned long)(*((c)++)))<<16; \
          case 3: l|=((unsigned long)(*((c)++)))<<24; \
          } }
  #define HOST_p_c2l_p(c,l,sc,len) {                  \
          switch (sc) {                   \
          case 0: l =((unsigned long)(*((c)++)));     \
              if (--len == 0) break;                                                 \
          case 1: l|=((unsigned long)(*((c)++)))<< 8; \
              if (--len == 0) break;                                                 \
          case 2: l|=((unsigned long)(*((c)++)))<<16; \
          } }
  /* NOTE the pointer is not incremented at the end of this */
  #define HOST_c2l_p(c,l,n)   {                   \
          l=0; (c)+=n;                    \
          switch (n) {                    \
          case 3: l =((unsigned long)(*(--(c))))<<16; \
          case 2: l|=((unsigned long)(*(--(c))))<< 8; \
          case 1: l|=((unsigned long)(*(--(c))));     \
          } }
  #define _HOST_l2c(l,c)  (*((c)++)=(unsigned char)(((l)    )&0xff),  \
                           *((c)++)=(unsigned char)(((l)>> 8)&0xff),  \
                           *((c)++)=(unsigned char)(((l)>>16)&0xff),  \
                           *((c)++)=(unsigned char)(((l)>>24)&0xff),  \
                           l)
  
  #endif
  
  /*
   * Time for some action:-)
   */
  
  int HASH_UPDATE (HASH_CTX *c, const void *data_, unsigned long len)
  {
      const unsigned char *data=(const unsigned char *)data_;
      register HASH_LONG * p;
      register unsigned long l;
      int sw,sc,ew,ec;
  
      if (len==0) return 1;
  
      l=(c->Nl+(len<<3))&0xffffffffL;
      /* 95-05-24 eay Fixed a bug with the overflow handling, thanks to
       * Wei Dai <weidai@eskimo.com> for pointing it out. */
      if (l < c->Nl) /* overflow */
          c->Nh++;
      c->Nh+=(len>>29);
      c->Nl=l;
  
      if (c->num != 0)
      {
          p=c->data;
          sw=c->num>>2;
          sc=c->num&0x03;
  
          if ((c->num+len) >= HASH_CBLOCK)
          {
              l=p[sw]; HOST_p_c2l(data,l,sc); p[sw++]=l;
              for (; sw<HASH_LBLOCK; sw++)
              {
                  HOST_c2l(data,l); p[sw]=l;
              }
              HASH_BLOCK_HOST_ORDER (c,p,1);
              len-=(HASH_CBLOCK-c->num);
              c->num=0;
              /* drop through and do the rest */
          }
          else
          {
              c->num+=len;
              if ((sc+len) < 4) /* ugly, add char's to a word */
              {
                  l=p[sw]; HOST_p_c2l_p(data,l,sc,len); p[sw]=l;
              }
              else
              {
                  ew=(c->num>>2);
                  ec=(c->num&0x03);
                  if (sc)
                      l=p[sw];
                  HOST_p_c2l(data,l,sc);
                  p[sw++]=l;
                  for (; sw < ew; sw++)
                  {
                      HOST_c2l(data,l); p[sw]=l;
                  }
                  if (ec)
                  {
                      HOST_c2l_p(data,l,ec); p[sw]=l;
                  }
              }
              return 1;
          }
      }
  
      sw=(int)(len/HASH_CBLOCK);
      if (sw > 0)
      {
  #if defined(HASH_BLOCK_DATA_ORDER_ALIGNED)
          /*
           * Note that HASH_BLOCK_DATA_ORDER_ALIGNED gets defined
           * only if sizeof(HASH_LONG)==4.
           */
          if ((((unsigned long)data)%4) == 0)
          {
              /* data is properly aligned so that we can cast it: */
              HASH_BLOCK_DATA_ORDER_ALIGNED (c,(HASH_LONG *)data,sw);
              sw*=HASH_CBLOCK;
              data+=sw;
              len-=sw;
          }
          else
  #if !defined(HASH_BLOCK_DATA_ORDER)
              while (sw--)
              {
                  mDNSPlatformMemCopy(p=c->data,data,HASH_CBLOCK);
                  HASH_BLOCK_DATA_ORDER_ALIGNED(c,p,1);
                  data+=HASH_CBLOCK;
                  len-=HASH_CBLOCK;
              }
  #endif
  #endif
  #if defined(HASH_BLOCK_DATA_ORDER)
          {
              HASH_BLOCK_DATA_ORDER(c,data,sw);
              sw*=HASH_CBLOCK;
              data+=sw;
              len-=sw;
          }
  #endif
      }
  
      if (len!=0)
      {
          p = c->data;
          c->num = (int)len;
          ew=(int)(len>>2);   /* words to copy */
          ec=(int)(len&0x03);
          for (; ew; ew--,p++)
          {
              HOST_c2l(data,l); *p=l;
          }
          HOST_c2l_p(data,l,ec);
          *p=l;
      }
      return 1;
  }
  
  
  void HASH_TRANSFORM (HASH_CTX *c, const unsigned char *data)
  {
  #if defined(HASH_BLOCK_DATA_ORDER_ALIGNED)
      if ((((unsigned long)data)%4) == 0)
          /* data is properly aligned so that we can cast it: */
          HASH_BLOCK_DATA_ORDER_ALIGNED (c,(HASH_LONG *)data,1);
      else
  #if !defined(HASH_BLOCK_DATA_ORDER)
      {
          mDNSPlatformMemCopy(c->data,data,HASH_CBLOCK);
          HASH_BLOCK_DATA_ORDER_ALIGNED (c,c->data,1);
      }
  #endif
  #endif
  #if defined(HASH_BLOCK_DATA_ORDER)
      HASH_BLOCK_DATA_ORDER (c,data,1);
  #endif
  }
  
  
  int HASH_FINAL (unsigned char *md, HASH_CTX *c)
  {
      register HASH_LONG *p;
      register unsigned long l;
      register int i,j;
      static const unsigned char end[4]={0x80,0x00,0x00,0x00};
      const unsigned char *cp=end;
  
      /* c->num should definitly have room for at least one more byte. */
      p=c->data;
      i=c->num>>2;
      j=c->num&0x03;
  
  #if 0
      /* purify often complains about the following line as an
       * Uninitialized Memory Read.  While this can be true, the
       * following p_c2l macro will reset l when that case is true.
       * This is because j&0x03 contains the number of 'valid' bytes
       * already in p[i].  If and only if j&0x03 == 0, the UMR will
       * occur but this is also the only time p_c2l will do
       * l= *(cp++) instead of l|= *(cp++)
       * Many thanks to Alex Tang <altitude@cic.net> for pickup this
       * 'potential bug' */
  #ifdef PURIFY
      if (j==0) p[i]=0; /* Yeah, but that's not the way to fix it:-) */
  #endif
      l=p[i];
  #else
      l = (j==0) ? 0 : p[i];
  #endif
      HOST_p_c2l(cp,l,j); p[i++]=l; /* i is the next 'undefined word' */
  
      if (i>(HASH_LBLOCK-2)) /* save room for Nl and Nh */
      {
          if (i<HASH_LBLOCK) p[i]=0;
          HASH_BLOCK_HOST_ORDER (c,p,1);
          i=0;
      }
      for (; i<(HASH_LBLOCK-2); i++)
          p[i]=0;
  
  #if   defined(DATA_ORDER_IS_BIG_ENDIAN)
      p[HASH_LBLOCK-2]=c->Nh;
      p[HASH_LBLOCK-1]=c->Nl;
  #elif defined(DATA_ORDER_IS_LITTLE_ENDIAN)
      p[HASH_LBLOCK-2]=c->Nl;
      p[HASH_LBLOCK-1]=c->Nh;
  #endif
      HASH_BLOCK_HOST_ORDER (c,p,1);
  
  #ifndef HASH_MAKE_STRING
  #error "HASH_MAKE_STRING must be defined!"
  #else
      HASH_MAKE_STRING(c,md);
  #endif
  
      c->num=0;
      /* clear stuff, HASH_BLOCK may be leaving some stuff on the stack
       * but I'm not worried :-)
         OPENSSL_cleanse((void *)c,sizeof(HASH_CTX));
       */
      return 1;
  }
  
  #ifndef MD32_REG_T
  #define MD32_REG_T long
  /*
   * This comment was originaly written for MD5, which is why it
   * discusses A-D. But it basically applies to all 32-bit digests,
   * which is why it was moved to common header file.
   *
   * In case you wonder why A-D are declared as long and not
   * as mDNSu32. Doing so results in slight performance
   * boost on LP64 architectures. The catch is we don't
   * really care if 32 MSBs of a 64-bit register get polluted
   * with eventual overflows as we *save* only 32 LSBs in
   * *either* case. Now declaring 'em long excuses the compiler
   * from keeping 32 MSBs zeroed resulting in 13% performance
   * improvement under SPARC Solaris7/64 and 5% under AlphaLinux.
   * Well, to be honest it should say that this *prevents*
   * performance degradation.
   *				<appro@fy.chalmers.se>
   * Apparently there're LP64 compilers that generate better
   * code if A-D are declared int. Most notably GCC-x86_64
   * generates better code.
   *				<appro@fy.chalmers.se>
   */
  #endif
  
  
  // from md5_locl.h (continued)
  
  /*
   #define	F(x,y,z)	(((x) & (y))  |  ((~(x)) & (z)))
   #define	G(x,y,z)	(((x) & (z))  |  ((y) & (~(z))))
   */
  
  /* As pointed out by Wei Dai <weidai@eskimo.com>, the above can be
   * simplified to the code below.  Wei attributes these optimizations
   * to Peter Gutmann's SHS code, and he attributes it to Rich Schroeppel.
   */
  #define F(b,c,d)    ((((c) ^ (d)) & (b)) ^ (d))
  #define G(b,c,d)    ((((b) ^ (c)) & (d)) ^ (c))
  #define H(b,c,d)    ((b) ^ (c) ^ (d))
  #define I(b,c,d)    (((~(d)) | (b)) ^ (c))
  
  #define R0(a,b,c,d,k,s,t) { \
          a+=((k)+(t)+F((b),(c),(d))); \
          a=ROTATE(a,s); \
          a+=b; }; \
  
  #define R1(a,b,c,d,k,s,t) { \
          a+=((k)+(t)+G((b),(c),(d))); \
          a=ROTATE(a,s); \
          a+=b; };
  
  #define R2(a,b,c,d,k,s,t) { \
          a+=((k)+(t)+H((b),(c),(d))); \
          a=ROTATE(a,s); \
          a+=b; };
  
  #define R3(a,b,c,d,k,s,t) { \
          a+=((k)+(t)+I((b),(c),(d))); \
          a=ROTATE(a,s); \
          a+=b; };
  
  // from md5_dgst.c
  
  
  /* Implemented from RFC1321 The MD5 Message-Digest Algorithm
   */
  
  #define INIT_DATA_A (unsigned long)0x67452301L
  #define INIT_DATA_B (unsigned long)0xefcdab89L
  #define INIT_DATA_C (unsigned long)0x98badcfeL
  #define INIT_DATA_D (unsigned long)0x10325476L
  
  int MD5_Init(MD5_CTX *c)
  {
      c->A=INIT_DATA_A;
      c->B=INIT_DATA_B;
      c->C=INIT_DATA_C;
      c->D=INIT_DATA_D;
      c->Nl=0;
      c->Nh=0;
      c->num=0;
      return 1;
  }
  
  #ifndef md5_block_host_order
  void md5_block_host_order (MD5_CTX *c, const void *data, int num)
  {
      const mDNSu32 *X=(const mDNSu32 *)data;
      register unsigned MD32_REG_T A,B,C,D;
  
      A=c->A;
      B=c->B;
      C=c->C;
      D=c->D;
  
      for (; num--; X+=HASH_LBLOCK)
      {
          /* Round 0 */
          R0(A,B,C,D,X[ 0], 7,0xd76aa478L);
          R0(D,A,B,C,X[ 1],12,0xe8c7b756L);
          R0(C,D,A,B,X[ 2],17,0x242070dbL);
          R0(B,C,D,A,X[ 3],22,0xc1bdceeeL);
          R0(A,B,C,D,X[ 4], 7,0xf57c0fafL);
          R0(D,A,B,C,X[ 5],12,0x4787c62aL);
          R0(C,D,A,B,X[ 6],17,0xa8304613L);
          R0(B,C,D,A,X[ 7],22,0xfd469501L);
          R0(A,B,C,D,X[ 8], 7,0x698098d8L);
          R0(D,A,B,C,X[ 9],12,0x8b44f7afL);
          R0(C,D,A,B,X[10],17,0xffff5bb1L);
          R0(B,C,D,A,X[11],22,0x895cd7beL);
          R0(A,B,C,D,X[12], 7,0x6b901122L);
          R0(D,A,B,C,X[13],12,0xfd987193L);
          R0(C,D,A,B,X[14],17,0xa679438eL);
          R0(B,C,D,A,X[15],22,0x49b40821L);
          /* Round 1 */
          R1(A,B,C,D,X[ 1], 5,0xf61e2562L);
          R1(D,A,B,C,X[ 6], 9,0xc040b340L);
          R1(C,D,A,B,X[11],14,0x265e5a51L);
          R1(B,C,D,A,X[ 0],20,0xe9b6c7aaL);
          R1(A,B,C,D,X[ 5], 5,0xd62f105dL);
          R1(D,A,B,C,X[10], 9,0x02441453L);
          R1(C,D,A,B,X[15],14,0xd8a1e681L);
          R1(B,C,D,A,X[ 4],20,0xe7d3fbc8L);
          R1(A,B,C,D,X[ 9], 5,0x21e1cde6L);
          R1(D,A,B,C,X[14], 9,0xc33707d6L);
          R1(C,D,A,B,X[ 3],14,0xf4d50d87L);
          R1(B,C,D,A,X[ 8],20,0x455a14edL);
          R1(A,B,C,D,X[13], 5,0xa9e3e905L);
          R1(D,A,B,C,X[ 2], 9,0xfcefa3f8L);
          R1(C,D,A,B,X[ 7],14,0x676f02d9L);
          R1(B,C,D,A,X[12],20,0x8d2a4c8aL);
          /* Round 2 */
          R2(A,B,C,D,X[ 5], 4,0xfffa3942L);
          R2(D,A,B,C,X[ 8],11,0x8771f681L);
          R2(C,D,A,B,X[11],16,0x6d9d6122L);
          R2(B,C,D,A,X[14],23,0xfde5380cL);
          R2(A,B,C,D,X[ 1], 4,0xa4beea44L);
          R2(D,A,B,C,X[ 4],11,0x4bdecfa9L);
          R2(C,D,A,B,X[ 7],16,0xf6bb4b60L);
          R2(B,C,D,A,X[10],23,0xbebfbc70L);
          R2(A,B,C,D,X[13], 4,0x289b7ec6L);
          R2(D,A,B,C,X[ 0],11,0xeaa127faL);
          R2(C,D,A,B,X[ 3],16,0xd4ef3085L);
          R2(B,C,D,A,X[ 6],23,0x04881d05L);
          R2(A,B,C,D,X[ 9], 4,0xd9d4d039L);
          R2(D,A,B,C,X[12],11,0xe6db99e5L);
          R2(C,D,A,B,X[15],16,0x1fa27cf8L);
          R2(B,C,D,A,X[ 2],23,0xc4ac5665L);
          /* Round 3 */
          R3(A,B,C,D,X[ 0], 6,0xf4292244L);
          R3(D,A,B,C,X[ 7],10,0x432aff97L);
          R3(C,D,A,B,X[14],15,0xab9423a7L);
          R3(B,C,D,A,X[ 5],21,0xfc93a039L);
          R3(A,B,C,D,X[12], 6,0x655b59c3L);
          R3(D,A,B,C,X[ 3],10,0x8f0ccc92L);
          R3(C,D,A,B,X[10],15,0xffeff47dL);
          R3(B,C,D,A,X[ 1],21,0x85845dd1L);
          R3(A,B,C,D,X[ 8], 6,0x6fa87e4fL);
          R3(D,A,B,C,X[15],10,0xfe2ce6e0L);
          R3(C,D,A,B,X[ 6],15,0xa3014314L);
          R3(B,C,D,A,X[13],21,0x4e0811a1L);
          R3(A,B,C,D,X[ 4], 6,0xf7537e82L);
          R3(D,A,B,C,X[11],10,0xbd3af235L);
          R3(C,D,A,B,X[ 2],15,0x2ad7d2bbL);
          R3(B,C,D,A,X[ 9],21,0xeb86d391L);
  
          A = c->A += A;
          B = c->B += B;
          C = c->C += C;
          D = c->D += D;
      }
  }
  #endif
  
  #ifndef md5_block_data_order
  #ifdef X
  #undef X
  #endif
  void md5_block_data_order (MD5_CTX *c, const void *data_, int num)
  {
      const unsigned char *data=data_;
      register unsigned MD32_REG_T A,B,C,D,l;
  #ifndef MD32_XARRAY
      /* See comment in crypto/sha/sha_locl.h for details. */
      unsigned MD32_REG_T XX0, XX1, XX2, XX3, XX4, XX5, XX6, XX7,
                          XX8, XX9,XX10,XX11,XX12,XX13,XX14,XX15;
  # define X(i)   XX ## i
  #else
      mDNSu32 XX[MD5_LBLOCK];
  # define X(i)   XX[i]
  #endif
  
      A=c->A;
      B=c->B;
      C=c->C;
      D=c->D;
  
      for (; num--;)
      {
          HOST_c2l(data,l); X( 0)=l;      HOST_c2l(data,l); X( 1)=l;
          /* Round 0 */
          R0(A,B,C,D,X( 0), 7,0xd76aa478L);   HOST_c2l(data,l); X( 2)=l;
          R0(D,A,B,C,X( 1),12,0xe8c7b756L);   HOST_c2l(data,l); X( 3)=l;
          R0(C,D,A,B,X( 2),17,0x242070dbL);   HOST_c2l(data,l); X( 4)=l;
          R0(B,C,D,A,X( 3),22,0xc1bdceeeL);   HOST_c2l(data,l); X( 5)=l;
          R0(A,B,C,D,X( 4), 7,0xf57c0fafL);   HOST_c2l(data,l); X( 6)=l;
          R0(D,A,B,C,X( 5),12,0x4787c62aL);   HOST_c2l(data,l); X( 7)=l;
          R0(C,D,A,B,X( 6),17,0xa8304613L);   HOST_c2l(data,l); X( 8)=l;
          R0(B,C,D,A,X( 7),22,0xfd469501L);   HOST_c2l(data,l); X( 9)=l;
          R0(A,B,C,D,X( 8), 7,0x698098d8L);   HOST_c2l(data,l); X(10)=l;
          R0(D,A,B,C,X( 9),12,0x8b44f7afL);   HOST_c2l(data,l); X(11)=l;
          R0(C,D,A,B,X(10),17,0xffff5bb1L);   HOST_c2l(data,l); X(12)=l;
          R0(B,C,D,A,X(11),22,0x895cd7beL);   HOST_c2l(data,l); X(13)=l;
          R0(A,B,C,D,X(12), 7,0x6b901122L);   HOST_c2l(data,l); X(14)=l;
          R0(D,A,B,C,X(13),12,0xfd987193L);   HOST_c2l(data,l); X(15)=l;
          R0(C,D,A,B,X(14),17,0xa679438eL);
          R0(B,C,D,A,X(15),22,0x49b40821L);
          /* Round 1 */
          R1(A,B,C,D,X( 1), 5,0xf61e2562L);
          R1(D,A,B,C,X( 6), 9,0xc040b340L);
          R1(C,D,A,B,X(11),14,0x265e5a51L);
          R1(B,C,D,A,X( 0),20,0xe9b6c7aaL);
          R1(A,B,C,D,X( 5), 5,0xd62f105dL);
          R1(D,A,B,C,X(10), 9,0x02441453L);
          R1(C,D,A,B,X(15),14,0xd8a1e681L);
          R1(B,C,D,A,X( 4),20,0xe7d3fbc8L);
          R1(A,B,C,D,X( 9), 5,0x21e1cde6L);
          R1(D,A,B,C,X(14), 9,0xc33707d6L);
          R1(C,D,A,B,X( 3),14,0xf4d50d87L);
          R1(B,C,D,A,X( 8),20,0x455a14edL);
          R1(A,B,C,D,X(13), 5,0xa9e3e905L);
          R1(D,A,B,C,X( 2), 9,0xfcefa3f8L);
          R1(C,D,A,B,X( 7),14,0x676f02d9L);
          R1(B,C,D,A,X(12),20,0x8d2a4c8aL);
          /* Round 2 */
          R2(A,B,C,D,X( 5), 4,0xfffa3942L);
          R2(D,A,B,C,X( 8),11,0x8771f681L);
          R2(C,D,A,B,X(11),16,0x6d9d6122L);
          R2(B,C,D,A,X(14),23,0xfde5380cL);
          R2(A,B,C,D,X( 1), 4,0xa4beea44L);
          R2(D,A,B,C,X( 4),11,0x4bdecfa9L);
          R2(C,D,A,B,X( 7),16,0xf6bb4b60L);
          R2(B,C,D,A,X(10),23,0xbebfbc70L);
          R2(A,B,C,D,X(13), 4,0x289b7ec6L);
          R2(D,A,B,C,X( 0),11,0xeaa127faL);
          R2(C,D,A,B,X( 3),16,0xd4ef3085L);
          R2(B,C,D,A,X( 6),23,0x04881d05L);
          R2(A,B,C,D,X( 9), 4,0xd9d4d039L);
          R2(D,A,B,C,X(12),11,0xe6db99e5L);
          R2(C,D,A,B,X(15),16,0x1fa27cf8L);
          R2(B,C,D,A,X( 2),23,0xc4ac5665L);
          /* Round 3 */
          R3(A,B,C,D,X( 0), 6,0xf4292244L);
          R3(D,A,B,C,X( 7),10,0x432aff97L);
          R3(C,D,A,B,X(14),15,0xab9423a7L);
          R3(B,C,D,A,X( 5),21,0xfc93a039L);
          R3(A,B,C,D,X(12), 6,0x655b59c3L);
          R3(D,A,B,C,X( 3),10,0x8f0ccc92L);
          R3(C,D,A,B,X(10),15,0xffeff47dL);
          R3(B,C,D,A,X( 1),21,0x85845dd1L);
          R3(A,B,C,D,X( 8), 6,0x6fa87e4fL);
          R3(D,A,B,C,X(15),10,0xfe2ce6e0L);
          R3(C,D,A,B,X( 6),15,0xa3014314L);
          R3(B,C,D,A,X(13),21,0x4e0811a1L);
          R3(A,B,C,D,X( 4), 6,0xf7537e82L);
          R3(D,A,B,C,X(11),10,0xbd3af235L);
          R3(C,D,A,B,X( 2),15,0x2ad7d2bbL);
          R3(B,C,D,A,X( 9),21,0xeb86d391L);
  
          A = c->A += A;
          B = c->B += B;
          C = c->C += C;
          D = c->D += D;
      }
  }
  #endif
  
  
  // ***************************************************************************
  #if COMPILER_LIKES_PRAGMA_MARK
  #pragma mark - base64 -> binary conversion
  #endif
  
  static const char Base64[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
  static const char Pad64 = '=';
  
  
  #define mDNSisspace(x) (x == '\t' || x == '\n' || x == '\v' || x == '\f' || x == '\r' || x == ' ')
  
  mDNSlocal const char *mDNSstrchr(const char *s, int c)
  {
      while (1)
      {
          if (c == *s) return s;
          if (!*s) return mDNSNULL;
          s++;
      }
  }
  
  // skips all whitespace anywhere.
  // converts characters, four at a time, starting at (or after)
  // src from base - 64 numbers into three 8 bit bytes in the target area.
  // it returns the number of data bytes stored at the target, or -1 on error.
  // adapted from BIND sources
  
  mDNSlocal mDNSs32 DNSDigest_Base64ToBin(const char *src, mDNSu8 *target, mDNSu32 targsize)
  {
      int tarindex, state, ch;
      const char *pos;
  
      state = 0;
      tarindex = 0;
  
      while ((ch = *src++) != '\0') {
          if (mDNSisspace(ch))    /* Skip whitespace anywhere. */
              continue;
  
          if (ch == Pad64)
              break;
  
          pos = mDNSstrchr(Base64, ch);
          if (pos == 0)       /* A non-base64 character. */
              return (-1);
  
          switch (state) {
          case 0:
              if (target) {
                  if ((mDNSu32)tarindex >= targsize)
                      return (-1);
                  target[tarindex] = (mDNSu8)((pos - Base64) << 2);
              }
              state = 1;
              break;
          case 1:
              if (target) {
                  if ((mDNSu32)tarindex + 1 >= targsize)
                      return (-1);
                  target[tarindex]   |=  (pos - Base64) >> 4;
                  target[tarindex+1]  = (mDNSu8)(((pos - Base64) & 0x0f) << 4);
              }
              tarindex++;
              state = 2;
              break;
          case 2:
              if (target) {
                  if ((mDNSu32)tarindex + 1 >= targsize)
                      return (-1);
                  target[tarindex]   |=  (pos - Base64) >> 2;
                  target[tarindex+1]  = (mDNSu8)(((pos - Base64) & 0x03) << 6);
              }
              tarindex++;
              state = 3;
              break;
          case 3:
              if (target) {
                  if ((mDNSu32)tarindex >= targsize)
                      return (-1);
                  target[tarindex] |= (pos - Base64);
              }
              tarindex++;
              state = 0;
              break;
          default:
              return -1;
          }
      }
  
      /*
       * We are done decoding Base-64 chars.  Let's see if we ended
       * on a byte boundary, and/or with erroneous trailing characters.
       */
  
      if (ch == Pad64) {      /* We got a pad char. */
          ch = *src++;        /* Skip it, get next. */
          switch (state) {
          case 0:     /* Invalid = in first position */
          case 1:     /* Invalid = in second position */
              return (-1);
  
          case 2:     /* Valid, means one byte of info */
              /* Skip any number of spaces. */
              for ((void)mDNSNULL; ch != '\0'; ch = *src++)
                  if (!mDNSisspace(ch))
                      break;
              /* Make sure there is another trailing = sign. */
              if (ch != Pad64)
                  return (-1);
              ch = *src++;        /* Skip the = */
          /* Fall through to "single trailing =" case. */
          /* FALLTHROUGH */
  
          case 3:     /* Valid, means two bytes of info */
              /*
               * We know this char is an =.  Is there anything but
               * whitespace after it?
               */
              for ((void)mDNSNULL; ch != '\0'; ch = *src++)
                  if (!mDNSisspace(ch))
                      return (-1);
  
              /*
               * Now make sure for cases 2 and 3 that the "extra"
               * bits that slopped past the last full byte were
               * zeros.  If we don't check them, they become a
               * subliminal channel.
               */
              if (target && target[tarindex] != 0)
                  return (-1);
          }
      } else {
          /*
           * We ended by seeing the end of the string.  Make sure we
           * have no partial bytes lying around.
           */
          if (state != 0)
              return (-1);
      }
  
      return (tarindex);
  }
  
  
  // ***************************************************************************
  #if COMPILER_LIKES_PRAGMA_MARK
  #pragma mark - API exported to mDNS Core
  #endif
  
  // Constants
  #define HMAC_IPAD   0x36
  #define HMAC_OPAD   0x5c
  #define MD5_LEN     16
  
  #define HMAC_MD5_AlgName (*(const domainname*) "\010" "hmac-md5" "\007" "sig-alg" "\003" "reg" "\003" "int")
  
  // Adapted from Appendix, RFC 2104
  mDNSlocal void DNSDigest_ConstructHMACKey(DomainAuthInfo *info, const mDNSu8 *key, mDNSu32 len)
  {
      MD5_CTX k;
      mDNSu8 buf[MD5_LEN];
      int i;
  
      // If key is longer than HMAC_LEN reset it to MD5(key)
      if (len > HMAC_LEN)
      {
          MD5_Init(&k);
          MD5_Update(&k, key, len);
          MD5_Final(buf, &k);
          key = buf;
          len = MD5_LEN;
      }
  
      // store key in pads
      mDNSPlatformMemZero(info->keydata_ipad, HMAC_LEN);
      mDNSPlatformMemZero(info->keydata_opad, HMAC_LEN);
      mDNSPlatformMemCopy(info->keydata_ipad, key, len);
      mDNSPlatformMemCopy(info->keydata_opad, key, len);
  
      // XOR key with ipad and opad values
      for (i = 0; i < HMAC_LEN; i++)
      {
          info->keydata_ipad[i] ^= HMAC_IPAD;
          info->keydata_opad[i] ^= HMAC_OPAD;
      }
  
  }
  
  mDNSexport mDNSs32 DNSDigest_ConstructHMACKeyfromBase64(DomainAuthInfo *info, const char *b64key)
  {
      mDNSu8 keybuf[1024];
      mDNSs32 keylen = DNSDigest_Base64ToBin(b64key, keybuf, sizeof(keybuf));
      if (keylen < 0) return(keylen);
      DNSDigest_ConstructHMACKey(info, keybuf, (mDNSu32)keylen);
      return(keylen);
  }
  
  mDNSexport void DNSDigest_SignMessage(DNSMessage *msg, mDNSu8 **end, DomainAuthInfo *info, mDNSu16 tcode)
  {
      AuthRecord tsig;
      mDNSu8  *rdata, *const countPtr = (mDNSu8 *)&msg->h.numAdditionals; // Get existing numAdditionals value
      mDNSu32 utc32;
      mDNSu8 utc48[6];
      mDNSu8 digest[MD5_LEN];
      mDNSu8 *ptr = *end;
      mDNSu32 len;
      mDNSOpaque16 buf;
      MD5_CTX c;
      mDNSu16 numAdditionals = (mDNSu16)((mDNSu16)countPtr[0] << 8 | countPtr[1]);
  
      // Init MD5 context, digest inner key pad and message
      MD5_Init(&c);
      MD5_Update(&c, info->keydata_ipad, HMAC_LEN);
      MD5_Update(&c, (mDNSu8 *)msg, (unsigned long)(*end - (mDNSu8 *)msg));
  
      // Construct TSIG RR, digesting variables as apporpriate
      mDNS_SetupResourceRecord(&tsig, mDNSNULL, 0, kDNSType_TSIG, 0, kDNSRecordTypeKnownUnique, AuthRecordAny, mDNSNULL, mDNSNULL);
  
      // key name
      AssignDomainName(&tsig.namestorage, &info->keyname);
      MD5_Update(&c, info->keyname.c, DomainNameLength(&info->keyname));
  
      // class
      tsig.resrec.rrclass = kDNSQClass_ANY;
      buf = mDNSOpaque16fromIntVal(kDNSQClass_ANY);
      MD5_Update(&c, buf.b, sizeof(mDNSOpaque16));
  
      // ttl
      tsig.resrec.rroriginalttl = 0;
      MD5_Update(&c, (mDNSu8 *)&tsig.resrec.rroriginalttl, sizeof(tsig.resrec.rroriginalttl));
  
      // alg name
      AssignDomainName(&tsig.resrec.rdata->u.name, &HMAC_MD5_AlgName);
      len = DomainNameLength(&HMAC_MD5_AlgName);
      rdata = tsig.resrec.rdata->u.data + len;
      MD5_Update(&c, HMAC_MD5_AlgName.c, len);
  
      // time
      // get UTC (universal time), convert to 48-bit unsigned in network byte order
      utc32 = (mDNSu32)mDNSPlatformUTC();
      if (utc32 == (unsigned)-1) { LogMsg("ERROR: DNSDigest_SignMessage - mDNSPlatformUTC returned bad time -1"); *end = mDNSNULL; }
      utc48[0] = 0;
      utc48[1] = 0;
      utc48[2] = (mDNSu8)((utc32 >> 24) & 0xff);
      utc48[3] = (mDNSu8)((utc32 >> 16) & 0xff);
      utc48[4] = (mDNSu8)((utc32 >>  8) & 0xff);
      utc48[5] = (mDNSu8)( utc32        & 0xff);
  
      mDNSPlatformMemCopy(rdata, utc48, 6);
      rdata += 6;
      MD5_Update(&c, utc48, 6);
  
      // 300 sec is fudge recommended in RFC 2485
      rdata[0] = (mDNSu8)((300 >> 8)  & 0xff);
      rdata[1] = (mDNSu8)( 300        & 0xff);
      MD5_Update(&c, rdata, sizeof(mDNSOpaque16));
      rdata += sizeof(mDNSOpaque16);
  
      // digest error (tcode) and other data len (zero) - we'll add them to the rdata later
      buf.b[0] = (mDNSu8)((tcode >> 8) & 0xff);
      buf.b[1] = (mDNSu8)( tcode       & 0xff);
      MD5_Update(&c, buf.b, sizeof(mDNSOpaque16));  // error
      buf.NotAnInteger = 0;
      MD5_Update(&c, buf.b, sizeof(mDNSOpaque16));  // other data len
  
      // finish the message & tsig var hash
      MD5_Final(digest, &c);
  
      // perform outer MD5 (outer key pad, inner digest)
      MD5_Init(&c);
      MD5_Update(&c, info->keydata_opad, HMAC_LEN);
      MD5_Update(&c, digest, MD5_LEN);
      MD5_Final(digest, &c);
  
      // set remaining rdata fields
      rdata[0] = (mDNSu8)((MD5_LEN >> 8)  & 0xff);
      rdata[1] = (mDNSu8)( MD5_LEN        & 0xff);
      rdata += sizeof(mDNSOpaque16);
      mDNSPlatformMemCopy(rdata, digest, MD5_LEN);                          // MAC
      rdata += MD5_LEN;
      rdata[0] = msg->h.id.b[0];                                            // original ID
      rdata[1] = msg->h.id.b[1];
      rdata[2] = (mDNSu8)((tcode >> 8) & 0xff);
      rdata[3] = (mDNSu8)( tcode       & 0xff);
      rdata[4] = 0;                                                         // other data len
      rdata[5] = 0;
      rdata += 6;
  
      tsig.resrec.rdlength = (mDNSu16)(rdata - tsig.resrec.rdata->u.data);
      *end = PutResourceRecordTTLJumbo(msg, ptr, &numAdditionals, &tsig.resrec, 0);
      if (!*end) { LogMsg("ERROR: DNSDigest_SignMessage - could not put TSIG"); *end = mDNSNULL; return; }
  
      // Write back updated numAdditionals value
      countPtr[0] = (mDNSu8)(numAdditionals >> 8);
      countPtr[1] = (mDNSu8)(numAdditionals &  0xFF);
  }
  
  mDNSexport mDNSBool DNSDigest_VerifyMessage(DNSMessage *msg, mDNSu8 *end, LargeCacheRecord * lcr, DomainAuthInfo *info, mDNSu16 * rcode, mDNSu16 * tcode)
  {
      mDNSu8          *   ptr = (mDNSu8*) &lcr->r.resrec.rdata->u.data;
      mDNSs32 now;
      mDNSs32 then;
      mDNSu8 thisDigest[MD5_LEN];
      mDNSu8 thatDigest[MD5_LEN];
      mDNSOpaque16 buf;
      mDNSu8 utc48[6];
      mDNSs32 delta;
      mDNSu16 fudge;
      domainname      *   algo;
      MD5_CTX c;
      mDNSBool ok = mDNSfalse;
  
      // We only support HMAC-MD5 for now
  
      algo = (domainname*) ptr;
  
      if (!SameDomainName(algo, &HMAC_MD5_AlgName))
      {
          LogMsg("ERROR: DNSDigest_VerifyMessage - TSIG algorithm not supported: %##s", algo->c);
          *rcode = kDNSFlag1_RC_NotAuth;
          *tcode = TSIG_ErrBadKey;
          ok = mDNSfalse;
          goto exit;
      }
  
      ptr += DomainNameLength(algo);
  
      // Check the times
  
      now = mDNSPlatformUTC();
      if (now == -1)
      {
          LogMsg("ERROR: DNSDigest_VerifyMessage - mDNSPlatformUTC returned bad time -1");
          *rcode = kDNSFlag1_RC_NotAuth;
          *tcode = TSIG_ErrBadTime;
          ok = mDNSfalse;
          goto exit;
      }
  
      // Get the 48 bit time field, skipping over the first word
  
      utc48[0] = *ptr++;
      utc48[1] = *ptr++;
      utc48[2] = *ptr++;
      utc48[3] = *ptr++;
      utc48[4] = *ptr++;
      utc48[5] = *ptr++;
  
      then  = (mDNSs32)NToH32(utc48 + sizeof(mDNSu16));
  
      fudge = NToH16(ptr);
  
      ptr += sizeof(mDNSu16);
  
      delta = (now > then) ? now - then : then - now;
  
      if (delta > fudge)
      {
          LogMsg("ERROR: DNSDigest_VerifyMessage - time skew > %d", fudge);
          *rcode = kDNSFlag1_RC_NotAuth;
          *tcode = TSIG_ErrBadTime;
          ok = mDNSfalse;
          goto exit;
      }
  
      // MAC size
  
      ptr += sizeof(mDNSu16);
  
      // MAC
  
      mDNSPlatformMemCopy(thatDigest, ptr, MD5_LEN);
  
      // Init MD5 context, digest inner key pad and message
  
      MD5_Init(&c);
      MD5_Update(&c, info->keydata_ipad, HMAC_LEN);
      MD5_Update(&c, (mDNSu8*) msg, (unsigned long)(end - (mDNSu8*) msg));
  
      // Key name
  
      MD5_Update(&c, lcr->r.resrec.name->c, DomainNameLength(lcr->r.resrec.name));
  
      // Class name
  
      buf = mDNSOpaque16fromIntVal(lcr->r.resrec.rrclass);
      MD5_Update(&c, buf.b, sizeof(mDNSOpaque16));
  
      // TTL
  
      MD5_Update(&c, (mDNSu8*) &lcr->r.resrec.rroriginalttl, sizeof(lcr->r.resrec.rroriginalttl));
  
      // Algorithm
  
      MD5_Update(&c, algo->c, DomainNameLength(algo));
  
      // Time
  
      MD5_Update(&c, utc48, 6);
  
      // Fudge
  
      buf = mDNSOpaque16fromIntVal(fudge);
      MD5_Update(&c, buf.b, sizeof(mDNSOpaque16));
  
      // Digest error and other data len (both zero) - we'll add them to the rdata later
  
      buf.NotAnInteger = 0;
      MD5_Update(&c, buf.b, sizeof(mDNSOpaque16));  // error
      MD5_Update(&c, buf.b, sizeof(mDNSOpaque16));  // other data len
  
      // Finish the message & tsig var hash
  
      MD5_Final(thisDigest, &c);
  
      // perform outer MD5 (outer key pad, inner digest)
  
      MD5_Init(&c);
      MD5_Update(&c, info->keydata_opad, HMAC_LEN);
      MD5_Update(&c, thisDigest, MD5_LEN);
      MD5_Final(thisDigest, &c);
  
      if (!mDNSPlatformMemSame(thisDigest, thatDigest, MD5_LEN))
      {
          LogMsg("ERROR: DNSDigest_VerifyMessage - bad signature");
          *rcode = kDNSFlag1_RC_NotAuth;
          *tcode = TSIG_ErrBadSig;
          ok = mDNSfalse;
          goto exit;
      }
  
      // set remaining rdata fields
      ok = mDNStrue;
  
  exit:
  
      return ok;
  }
  
  
  #ifdef __cplusplus
  }
  #endif
  
  