Commit | Line | Data |
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1da177e4 LT |
1 | |
2 | /* | |
3 | * Keyed 32-bit hash function using TEA in a Davis-Meyer function | |
4 | * H0 = Key | |
5 | * Hi = E Mi(Hi-1) + Hi-1 | |
6 | * | |
7 | * (see Applied Cryptography, 2nd edition, p448). | |
8 | * | |
9 | * Jeremy Fitzhardinge <jeremy@zip.com.au> 1998 | |
10 | * | |
11 | * Jeremy has agreed to the contents of reiserfs/README. -Hans | |
12 | * Yura's function is added (04/07/2000) | |
13 | */ | |
14 | ||
15 | // | |
16 | // keyed_hash | |
17 | // yura_hash | |
18 | // r5_hash | |
19 | // | |
20 | ||
21 | #include <linux/kernel.h> | |
22 | #include <asm/types.h> | |
23 | #include <asm/bug.h> | |
24 | ||
25 | ||
26 | #define DELTA 0x9E3779B9 | |
27 | #define FULLROUNDS 10 /* 32 is overkill, 16 is strong crypto */ | |
28 | #define PARTROUNDS 6 /* 6 gets complete mixing */ | |
29 | ||
30 | /* a, b, c, d - data; h0, h1 - accumulated hash */ | |
31 | #define TEACORE(rounds) \ | |
32 | do { \ | |
33 | u32 sum = 0; \ | |
34 | int n = rounds; \ | |
35 | u32 b0, b1; \ | |
36 | \ | |
37 | b0 = h0; \ | |
38 | b1 = h1; \ | |
39 | \ | |
40 | do \ | |
41 | { \ | |
42 | sum += DELTA; \ | |
43 | b0 += ((b1 << 4)+a) ^ (b1+sum) ^ ((b1 >> 5)+b); \ | |
44 | b1 += ((b0 << 4)+c) ^ (b0+sum) ^ ((b0 >> 5)+d); \ | |
45 | } while(--n); \ | |
46 | \ | |
47 | h0 += b0; \ | |
48 | h1 += b1; \ | |
49 | } while(0) | |
50 | ||
51 | ||
52 | u32 keyed_hash(const signed char *msg, int len) | |
53 | { | |
54 | u32 k[] = { 0x9464a485, 0x542e1a94, 0x3e846bff, 0xb75bcfc3}; | |
55 | ||
56 | u32 h0 = k[0], h1 = k[1]; | |
57 | u32 a, b, c, d; | |
58 | u32 pad; | |
59 | int i; | |
60 | ||
61 | // assert(len >= 0 && len < 256); | |
62 | ||
63 | pad = (u32)len | ((u32)len << 8); | |
64 | pad |= pad << 16; | |
65 | ||
66 | while(len >= 16) | |
67 | { | |
68 | a = (u32)msg[ 0] | | |
69 | (u32)msg[ 1] << 8 | | |
70 | (u32)msg[ 2] << 16| | |
71 | (u32)msg[ 3] << 24; | |
72 | b = (u32)msg[ 4] | | |
73 | (u32)msg[ 5] << 8 | | |
74 | (u32)msg[ 6] << 16| | |
75 | (u32)msg[ 7] << 24; | |
76 | c = (u32)msg[ 8] | | |
77 | (u32)msg[ 9] << 8 | | |
78 | (u32)msg[10] << 16| | |
79 | (u32)msg[11] << 24; | |
80 | d = (u32)msg[12] | | |
81 | (u32)msg[13] << 8 | | |
82 | (u32)msg[14] << 16| | |
83 | (u32)msg[15] << 24; | |
84 | ||
85 | TEACORE(PARTROUNDS); | |
86 | ||
87 | len -= 16; | |
88 | msg += 16; | |
89 | } | |
90 | ||
91 | if (len >= 12) | |
92 | { | |
93 | a = (u32)msg[ 0] | | |
94 | (u32)msg[ 1] << 8 | | |
95 | (u32)msg[ 2] << 16| | |
96 | (u32)msg[ 3] << 24; | |
97 | b = (u32)msg[ 4] | | |
98 | (u32)msg[ 5] << 8 | | |
99 | (u32)msg[ 6] << 16| | |
100 | (u32)msg[ 7] << 24; | |
101 | c = (u32)msg[ 8] | | |
102 | (u32)msg[ 9] << 8 | | |
103 | (u32)msg[10] << 16| | |
104 | (u32)msg[11] << 24; | |
105 | ||
106 | d = pad; | |
107 | for(i = 12; i < len; i++) | |
108 | { | |
109 | d <<= 8; | |
110 | d |= msg[i]; | |
111 | } | |
112 | } | |
113 | else if (len >= 8) | |
114 | { | |
115 | a = (u32)msg[ 0] | | |
116 | (u32)msg[ 1] << 8 | | |
117 | (u32)msg[ 2] << 16| | |
118 | (u32)msg[ 3] << 24; | |
119 | b = (u32)msg[ 4] | | |
120 | (u32)msg[ 5] << 8 | | |
121 | (u32)msg[ 6] << 16| | |
122 | (u32)msg[ 7] << 24; | |
123 | ||
124 | c = d = pad; | |
125 | for(i = 8; i < len; i++) | |
126 | { | |
127 | c <<= 8; | |
128 | c |= msg[i]; | |
129 | } | |
130 | } | |
131 | else if (len >= 4) | |
132 | { | |
133 | a = (u32)msg[ 0] | | |
134 | (u32)msg[ 1] << 8 | | |
135 | (u32)msg[ 2] << 16| | |
136 | (u32)msg[ 3] << 24; | |
137 | ||
138 | b = c = d = pad; | |
139 | for(i = 4; i < len; i++) | |
140 | { | |
141 | b <<= 8; | |
142 | b |= msg[i]; | |
143 | } | |
144 | } | |
145 | else | |
146 | { | |
147 | a = b = c = d = pad; | |
148 | for(i = 0; i < len; i++) | |
149 | { | |
150 | a <<= 8; | |
151 | a |= msg[i]; | |
152 | } | |
153 | } | |
154 | ||
155 | TEACORE(FULLROUNDS); | |
156 | ||
157 | /* return 0;*/ | |
158 | return h0^h1; | |
159 | } | |
160 | ||
161 | /* What follows in this file is copyright 2000 by Hans Reiser, and the | |
162 | * licensing of what follows is governed by reiserfs/README */ | |
163 | ||
164 | u32 yura_hash (const signed char *msg, int len) | |
165 | { | |
166 | int j, pow; | |
167 | u32 a, c; | |
168 | int i; | |
169 | ||
170 | for (pow=1,i=1; i < len; i++) pow = pow * 10; | |
171 | ||
172 | if (len == 1) | |
173 | a = msg[0]-48; | |
174 | else | |
175 | a = (msg[0] - 48) * pow; | |
176 | ||
177 | for (i=1; i < len; i++) { | |
178 | c = msg[i] - 48; | |
179 | for (pow=1,j=i; j < len-1; j++) pow = pow * 10; | |
180 | a = a + c * pow; | |
181 | } | |
182 | ||
183 | for (; i < 40; i++) { | |
184 | c = '0' - 48; | |
185 | for (pow=1,j=i; j < len-1; j++) pow = pow * 10; | |
186 | a = a + c * pow; | |
187 | } | |
188 | ||
189 | for (; i < 256; i++) { | |
190 | c = i; | |
191 | for (pow=1,j=i; j < len-1; j++) pow = pow * 10; | |
192 | a = a + c * pow; | |
193 | } | |
194 | ||
195 | a = a << 7; | |
196 | return a; | |
197 | } | |
198 | ||
199 | u32 r5_hash (const signed char *msg, int len) | |
200 | { | |
201 | u32 a=0; | |
202 | while(*msg) { | |
203 | a += *msg << 4; | |
204 | a += *msg >> 4; | |
205 | a *= 11; | |
206 | msg++; | |
207 | } | |
208 | return a; | |
209 | } |