summaryrefslogtreecommitdiffstats
path: root/xlators/cluster/dht/src/dht-hashfn-tea.c
blob: 8437b4955416a692cf1d91efd96ff587b077a6b8 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
/*
   Copyright (c) 2008 Z RESEARCH, Inc. <http://www.zresearch.com>
   This file is part of GlusterFS.

   GlusterFS 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 3 of the License,
   or (at your option) any later version.

   GlusterFS 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, see
   <http://www.gnu.org/licenses/>.
*/


#include <stdint.h>
#include <stdio.h>
#include <string.h>


#define DELTA 0x9E3779B9
#define FULLROUNDS 10		/* 32 is overkill, 16 is strong crypto */
#define PARTROUNDS 6		/* 6 gets complete mixing */


static int
tearound (int rounds, uint32_t *array, uint32_t *h0, uint32_t *h1)
{
	uint32_t sum = 0;
	int      n = 0;
	uint32_t b0  = 0;
	uint32_t b1  = 0;

	b0 = *h0;
	b1 = *h1;

	n = rounds;

	do {
		sum += DELTA;
		b0  += ((b1 << 4) + array[0])
			^ (b1 + sum)
			^ ((b1 >> 5) + array[1]);
		b1  += ((b0 << 4) + array[2])
			^ (b0 + sum)
			^ ((b0 >> 5) + array[3]);
	} while (--n);

	*h0 += b0;
	*h1 += b1;

	return 0;
}


uint32_t
__pad (int len)
{
	uint32_t pad = 0;

	pad = (uint32_t) len | ((uint32_t) len << 8);
	pad |= pad << 16;

	return pad;
}


uint32_t
dht_hashfn_tea (const char *msg, int len)
{
	uint32_t  h0 = 0x9464a485;
	uint32_t  h1 = 0x542e1a94;
	uint32_t  array[4];
	uint32_t  pad = 0;
	int       i = 0;
	int       j = 0;
	int       full_quads = 0;
	int       full_words = 0;
	int       full_bytes = 0;
	uint32_t *intmsg = NULL;
	int       word = 0;


	intmsg = (uint32_t *) msg;
	pad = __pad (len);

	full_bytes   = len;
	full_words   = len / 4;
	full_quads   = len / 16;

	for (i = 0; i < full_quads; i++) {
		for (j = 0; j < 4; j++) {
			word     = *intmsg;
			array[j] = word;
			intmsg++;
			full_words--;
			full_bytes -= 4;
		}
		tearound (PARTROUNDS, &array[0], &h0, &h1);
	}

	if ((len % 16) == 0) {
		goto done;
	}

	for (j = 0; j < 4; j++) {
		if (full_words) {
			word     = *intmsg;
			array[j] = word;
			intmsg++;
			full_words--;
			full_bytes -= 4;
		} else {
			array[j] = pad;
			while (full_bytes) {
				array[j] <<= 8;
				array[j] |= msg[len - full_bytes];
				full_bytes--;
			}
		}
	}
	tearound (FULLROUNDS, &array[0], &h0, &h1);

done:
	return h0 ^ h1;
}


#if 0
int
main (int argc, char *argv[])
{
	int i = 0;
	int hashval = 0;

	for (i = 1; i < argc; i++) {
		hashval = tea (argv[i], strlen (argv[i]));
		printf ("%s: %x\n", argv[i], hashval);
	}
}
#endif