#include <stdio.h>
#include <stdlib.h>
#include <sys/time.h>

#include "md5.h"
#include "random.h"
#include "externs.h"
#include "strings.h"

#include "pw-b.h"

#define MIN_ROUNDS 32
#define DEF_ROUNDS 256
#define MAX_ROUNDS 65536

/* don't casually change either of these; too many things depend on them */
static const char alphabet[] = "!\"#$%&'()*+,-./0123456789:;<=>?@"
			       "ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`"
			       "abcdefghijklmnopqrstuvwxyz{|}~";
#define BASE 94

static unsigned int base_div(unsigned char *v)
{
 unsigned int r;
 int i;

 r = 0;
 for (i=0;i<16;i++)
  { r = (r << 8) + v[i];
    v[i] = r / BASE;
    r %= BASE;
  }
 return(r);
}

static void base_expand(const unsigned char *res, char *txt)
{
 int i;
 unsigned char tmp[16];

 bcopy(res,&tmp[0],16);
 for (i=0;i<20;i++) txt[i] = alphabet[base_div(&tmp[0])];
}

int pw_b_check(const char *pass, const char *plain)
{
 void *s;
 char *pp;
 int r;
 int i;
 unsigned char md5res[20];
 char text[20];
 const void *data;
 int datalen;

 r = strtol(pass,&pp,10);
 if ((r < MIN_ROUNDS) || (r > MAX_ROUNDS)) return(1);
 if (*pp++ != '.') return(1);
 if (strlen(pp) != 40) return(1);
 data = plain;
 datalen = strlen(plain);
 for (i=0;i<r;i++)
  { s = md5_init();
    md5_process_bytes(s,data,datalen);
    md5_process_bytes(s,pp,20);
    md5_process_bytes(s,data,datalen);
    md5_process_bytes(s,plain,strlen(plain));
    md5_process_bytes(s,data,datalen);
    md5_result(s,&md5res[0]);
    base_expand(&md5res[0],&text[0]);
    data = &text[0];
    datalen = 20;
  }
 return(bcmp(&text[0],pp+20,20));
}

char *pw_b_make(const char *plain)
{
 void *s;
 int i;
 unsigned char binsalt[12];
 unsigned char md5res[16];
 char *text;
 char *tp;
 const void *data;
 int datalen;
 struct timeval tv;

 text = malloc(75);
 sprintf(text,"%d.",DEF_ROUNDS);
 tp = text + strlen(text);
 gettimeofday(&tv,0);
 binsalt[0] =  tv.tv_sec        & 0xff;
 binsalt[1] = (tv.tv_sec >>  8) & 0xff;
 binsalt[2] = (tv.tv_sec >> 16) & 0xff;
 binsalt[3] = (tv.tv_sec >> 24) & 0xff;
 binsalt[4] =  tv.tv_usec        & 0xff;
 binsalt[5] = (tv.tv_usec >>  8) & 0xff;
 binsalt[6] = (tv.tv_usec >> 16) & 0xff;
 binsalt[7] = (tv.tv_usec >> 24) & 0xff;
 i = rndint();
 binsalt[8] = i & 0xff;
 binsalt[9] = (i >> 8) & 0xff;
 binsalt[10] = (i >> 16) & 0xff;
 binsalt[11] = (i >> 24) & 0xff;
 s = md5_init();
 md5_process_bytes(s,&binsalt[0],12);
 md5_result(s,&md5res[0]);
 base_expand(&md5res[0],tp);
 data = plain;
 datalen = strlen(plain);
 for (i=0;i<DEF_ROUNDS;i++)
  { s = md5_init();
    md5_process_bytes(s,data,datalen);
    md5_process_bytes(s,tp,20);
    md5_process_bytes(s,data,datalen);
    md5_process_bytes(s,plain,strlen(plain));
    md5_process_bytes(s,data,datalen);
    md5_result(s,&md5res[0]);
    base_expand(&md5res[0],tp+20);
    data = tp + 20;
    datalen = 20;
  }
 tp[40] = '\0';
 return(text);
}