added a --partial option which tells rsync to keep partially

[rsync/rsync.git] / md4.c

/*
   This code is from rfc1186. 

   It has been modified to use the SIVAL() macro to make it
   byte order and length independent, so we don't need the LOWBYTEFIRST define
*/

 /*
 ** ********************************************************************
 ** md4.c -- Implementation of MD4 Message Digest Algorithm           **
 ** Updated: 2/16/90 by Ronald L. Rivest                              **
 ** (C) 1990 RSA Data Security, Inc.                                  **
 ** ********************************************************************
 */

 /*
 ** To use MD4:
 **   -- Include md4.h in your program
 **   -- Declare an MDstruct MD to hold the state of the digest
 **          computation.
 **   -- Initialize MD using MDbegin(&MD)
 **   -- For each full block (64 bytes) X you wish to process, call
 **          MDupdate(&MD,X,512)
 **      (512 is the number of bits in a full block.)
 **   -- For the last block (less than 64 bytes) you wish to process,
 **          MDupdate(&MD,X,n)
 **      where n is the number of bits in the partial block. A partial
 **      block terminates the computation, so every MD computation
 **      should terminate by processing a partial block, even if it
 **      has n = 0.
 **   -- The message digest is available in MD.buffer[0] ...
 **      MD.buffer[3].  (Least-significant byte of each word
 **      should be output first.)
 **   -- You can print out the digest using MDprint(&MD)
 */

#define TRUE  1
#define FALSE 0

 /* Compile-time includes
 */

#include "rsync.h"

 /* Compile-time declarations of MD4 "magic constants".
 */
#define I0  0x67452301       /* Initial values for MD buffer */
#define I1  0xefcdab89
#define I2  0x98badcfe
#define I3  0x10325476
#define C2  013240474631     /* round 2 constant = sqrt(2) in octal */
#define C3  015666365641     /* round 3 constant = sqrt(3) in octal */
 /* C2 and C3 are from Knuth, The Art of Programming, Volume 2
 ** (Seminumerical Algorithms), Second Edition (1981), Addison-Wesley.
 ** Table 2, page 660.
 */

#define fs1  3               /* round 1 shift amounts */
#define fs2  7
#define fs3 11
#define fs4 19
#define gs1  3               /* round 2 shift amounts */
#define gs2  5
#define gs3  9
#define gs4 13
#define hs1  3               /* round 3 shift amounts */
#define hs2  9
#define hs3 11
#define hs4 15

 /* Compile-time macro declarations for MD4.
 ** Note: The "rot" operator uses the variable "tmp".
 ** It assumes tmp is declared as unsigned int, so that the >>
 ** operator will shift in zeros rather than extending the sign bit.
 */
#define f(X,Y,Z)             ((X&Y) | ((~X)&Z))
#define g(X,Y,Z)             ((X&Y) | (X&Z) | (Y&Z))
#define h(X,Y,Z)             (X^Y^Z)
#define rot(X,S)             (tmp=X,(tmp<<S) | (tmp>>(32-S)))
#define ff(A,B,C,D,i,s)      A = rot((A + f(B,C,D) + X[i]),s)
#define gg(A,B,C,D,i,s)      A = rot((A + g(B,C,D) + X[i] + C2),s)
#define hh(A,B,C,D,i,s)      A = rot((A + h(B,C,D) + X[i] + C3),s)

 /* MDbegin(MDp)
 ** Initialize message digest buffer MDp.
 ** This is a user-callable routine.
 */
 void
 MDbegin(MDp)
 MDptr MDp;
 { int i;
   MDp->buffer[0] = I0;
   MDp->buffer[1] = I1;
   MDp->buffer[2] = I2;
   MDp->buffer[3] = I3;
   for (i=0;i<8;i++) MDp->count[i] = 0;
   MDp->done = 0;
 }

 /* MDreverse(X)
 ** Reverse the byte-ordering of every int in X.
 ** Assumes X is an array of 16 ints.
 ** The macro revx reverses the byte-ordering of the next word of X.
 */
 void MDreverse(X)
 unsigned int32 *X;
 { register unsigned int32 t;
   register unsigned int i;

   for(i = 0; i < 16; i++) {
	  t = X[i];
	  SIVAL(X,i*4,t);
	}
 }

 /* MDblock(MDp,X)
 ** Update message digest buffer MDp->buffer using 16-word data block X.
 ** Assumes all 16 words of X are full of data.
 ** Does not update MDp->count.
 ** This routine is not user-callable.
 */
 static void
 MDblock(MDp,X)
 MDptr MDp;
 unsigned int32 *X;
 {
   register unsigned int32 tmp, A, B, C, D;
   MDreverse(X);
   A = MDp->buffer[0];
   B = MDp->buffer[1];
   C = MDp->buffer[2];
   D = MDp->buffer[3];
   /* Update the message digest buffer */
   ff(A , B , C , D ,  0 , fs1); /* Round 1 */
   ff(D , A , B , C ,  1 , fs2);
   ff(C , D , A , B ,  2 , fs3);
   ff(B , C , D , A ,  3 , fs4);
   ff(A , B , C , D ,  4 , fs1);
   ff(D , A , B , C ,  5 , fs2);
   ff(C , D , A , B ,  6 , fs3);
   ff(B , C , D , A ,  7 , fs4);
   ff(A , B , C , D ,  8 , fs1);
   ff(D , A , B , C ,  9 , fs2);
   ff(C , D , A , B , 10 , fs3);
   ff(B , C , D , A , 11 , fs4);
   ff(A , B , C , D , 12 , fs1);
   ff(D , A , B , C , 13 , fs2);
   ff(C , D , A , B , 14 , fs3);
   ff(B , C , D , A , 15 , fs4);
   gg(A , B , C , D ,  0 , gs1); /* Round 2 */
   gg(D , A , B , C ,  4 , gs2);
   gg(C , D , A , B ,  8 , gs3);
   gg(B , C , D , A , 12 , gs4);
   gg(A , B , C , D ,  1 , gs1);
   gg(D , A , B , C ,  5 , gs2);
   gg(C , D , A , B ,  9 , gs3);
   gg(B , C , D , A , 13 , gs4);
   gg(A , B , C , D ,  2 , gs1);
   gg(D , A , B , C ,  6 , gs2);
   gg(C , D , A , B , 10 , gs3);
   gg(B , C , D , A , 14 , gs4);
   gg(A , B , C , D ,  3 , gs1);
   gg(D , A , B , C ,  7 , gs2);
   gg(C , D , A , B , 11 , gs3);
   gg(B , C , D , A , 15 , gs4);
   hh(A , B , C , D ,  0 , hs1); /* Round 3 */
   hh(D , A , B , C ,  8 , hs2);
   hh(C , D , A , B ,  4 , hs3);
   hh(B , C , D , A , 12 , hs4);
   hh(A , B , C , D ,  2 , hs1);
   hh(D , A , B , C , 10 , hs2);
   hh(C , D , A , B ,  6 , hs3);
   hh(B , C , D , A , 14 , hs4);
   hh(A , B , C , D ,  1 , hs1);
   hh(D , A , B , C ,  9 , hs2);
   hh(C , D , A , B ,  5 , hs3);
   hh(B , C , D , A , 13 , hs4);
   hh(A , B , C , D ,  3 , hs1);
   hh(D , A , B , C , 11 , hs2);
   hh(C , D , A , B ,  7 , hs3);
   hh(B , C , D , A , 15 , hs4);
   MDp->buffer[0] += A;
   MDp->buffer[1] += B;
   MDp->buffer[2] += C;
   MDp->buffer[3] += D;
 }

 /* MDupdate(MDp,X,count)
 ** Input: MDp -- an MDptr
 **        X -- a pointer to an array of unsigned characters.
 **        count -- the number of bits of X to use.
 **          (if not a multiple of 8, uses high bits of last byte.)
 ** Update MDp using the number of bits of X given by count.
 ** This is the basic input routine for an MD4 user.
 ** The routine completes the MD computation when count < 512, so
 ** every MD computation should end with one call to MDupdate with a
 ** count less than 512.  A call with count 0 will be ignored if the
 ** MD has already been terminated (done != 0), so an extra call with
 ** count 0 can be given as a "courtesy close" to force termination
 ** if desired.
 */
 void
 MDupdate(MDp,X,count)
 MDptr MDp;
 unsigned char *X;
 unsigned int count;
 { unsigned int32 i, tmp, bit, byte, mask;
   unsigned char XX[64];
   unsigned char *p;
   /* return with no error if this is a courtesy close with count
   ** zero and MDp->done is true.
   */
   if (count == 0 && MDp->done) return;
   /* check to see if MD is already done and report error */
   if (MDp->done)
          { rprintf(FERROR,"\nError: MDupdate MD already done."); return; }
   /* Add count to MDp->count */
   tmp = count;
   p = MDp->count;
   while (tmp)
     { tmp += *p;
       *p++ = tmp;
       tmp = tmp >> 8;
     }
   /* Process data */
   if (count == 512)
     { /* Full block of data to handle */
       MDblock(MDp,(unsigned int *)X);
     }
   else if (count > 512) /* Check for count too large */
     { rprintf(FERROR,"\nError: MDupdate called with illegal count value %d."
              ,count);
       return;
     }
   else /* partial block -- must be last block so finish up */
     { /* Find out how many bytes and residual bits there are */
       byte = count >> 3;
       bit =  count & 7;
       /* Copy X into XX since we need to modify it */
       for (i=0;i<=byte;i++)   XX[i] = X[i];
       for (i=byte+1;i<64;i++) XX[i] = 0;
       /* Add padding '1' bit and low-order zeros in last byte */
       mask = 1 << (7 - bit);
       XX[byte] = (XX[byte] | mask) & ~( mask - 1);
       /* If room for bit count, finish up with this block */
       if (byte <= 55)
         { for (i=0;i<8;i++) XX[56+i] = MDp->count[i];
           MDblock(MDp,(unsigned int32 *)XX);
         }
       else /* need to do two blocks to finish up */
         { MDblock(MDp,(unsigned int32 *)XX);
           for (i=0;i<56;i++) XX[i] = 0;
           for (i=0;i<8;i++)  XX[56+i] = MDp->count[i];
           MDblock(MDp,(unsigned int32 *)XX);
         }
       /* Set flag saying we're done with MD computation */
       MDp->done = 1;
     }
 }

 /*
 ** End of md4.c
 */