2 * Copyright (C) 2002 by Theodore Ts'o
4 * This file is released under the GPL v2.
6 * This file may be redistributed under the terms of the GNU Public
11 * obdclass/hash.c is copied from ldiskfs/hash.c.
12 * ldiskfs is used by server only.
13 * obdclass is shared by both client and server, it should not depend on ldiskfs.
17 #include <linux/jbd.h>
18 #include <linux/sched.h>
19 #ifdef HAVE_SERVER_SUPPORT
20 # include <linux/ldiskfs_fs.h>
22 # include <obd_class.h>
25 #define DELTA 0x9E3779B9
27 #define DX_HASH_SAME 99
30 static void TEA_transform(__u32 buf[4], __u32 const in[])
33 __u32 b0 = buf[0], b1 = buf[1];
34 __u32 a = in[0], b = in[1], c = in[2], d = in[3];
39 b0 += ((b1 << 4)+a) ^ (b1+sum) ^ ((b1 >> 5)+b);
40 b1 += ((b0 << 4)+c) ^ (b0+sum) ^ ((b0 >> 5)+d);
47 /* F, G and H are basic MD4 functions: selection, majority, parity */
48 #define F(x, y, z) ((z) ^ ((x) & ((y) ^ (z))))
49 #define G(x, y, z) (((x) & (y)) + (((x) ^ (y)) & (z)))
50 #define H(x, y, z) ((x) ^ (y) ^ (z))
53 * The generic round function. The application is so specific that
54 * we don't bother protecting all the arguments with parens, as is generally
55 * good macro practice, in favor of extra legibility.
56 * Rotation is separate from addition to prevent recomputation
58 #define ROUND(f, a, b, c, d, x, s) \
59 (a += f(b, c, d) + x, a = (a << s) | (a >> (32-s)))
61 #define K2 013240474631UL
62 #define K3 015666365641UL
65 * Basic cut-down MD4 transform. Returns only 32 bits of result.
67 static void halfMD4Transform (__u32 buf[4], __u32 const in[])
69 __u32 a = buf[0], b = buf[1], c = buf[2], d = buf[3];
72 ROUND(F, a, b, c, d, in[0] + K1, 3);
73 ROUND(F, d, a, b, c, in[1] + K1, 7);
74 ROUND(F, c, d, a, b, in[2] + K1, 11);
75 ROUND(F, b, c, d, a, in[3] + K1, 19);
76 ROUND(F, a, b, c, d, in[4] + K1, 3);
77 ROUND(F, d, a, b, c, in[5] + K1, 7);
78 ROUND(F, c, d, a, b, in[6] + K1, 11);
79 ROUND(F, b, c, d, a, in[7] + K1, 19);
82 ROUND(G, a, b, c, d, in[1] + K2, 3);
83 ROUND(G, d, a, b, c, in[3] + K2, 5);
84 ROUND(G, c, d, a, b, in[5] + K2, 9);
85 ROUND(G, b, c, d, a, in[7] + K2, 13);
86 ROUND(G, a, b, c, d, in[0] + K2, 3);
87 ROUND(G, d, a, b, c, in[2] + K2, 5);
88 ROUND(G, c, d, a, b, in[4] + K2, 9);
89 ROUND(G, b, c, d, a, in[6] + K2, 13);
92 ROUND(H, a, b, c, d, in[3] + K3, 3);
93 ROUND(H, d, a, b, c, in[7] + K3, 9);
94 ROUND(H, c, d, a, b, in[2] + K3, 11);
95 ROUND(H, b, c, d, a, in[6] + K3, 15);
96 ROUND(H, a, b, c, d, in[1] + K3, 3);
97 ROUND(H, d, a, b, c, in[5] + K3, 9);
98 ROUND(H, c, d, a, b, in[0] + K3, 11);
99 ROUND(H, b, c, d, a, in[4] + K3, 15);
115 /* The old legacy hash */
116 static __u32 dx_hack_hash (const char *name, int len)
118 __u32 hash0 = 0x12a3fe2d, hash1 = 0x37abe8f9;
120 __u32 hash = hash1 + (hash0 ^ (*name++ * 7152373));
122 if (hash & 0x80000000) hash -= 0x7fffffff;
129 static __u32 dx_r5_hash(const signed char *msg, int len)
141 static __u32 dx_same_hash(const signed char *msg, int len)
146 static void str2hashbuf(const char *msg, int len, __u32 *buf, int num)
151 pad = (__u32)len | ((__u32)len << 8);
157 for (i=0; i < len; i++) {
160 val = msg[i] + (val << 8);
174 * Returns the hash of a filename. If len is 0 and name is NULL, then
175 * this function can be used to test whether or not a hash version is
178 * The seed is an 4 longword (32 bits) "secret" which can be used to
179 * uniquify a hash. If the seed is all zero's, then some default seed
182 * A particular hash version specifies whether or not the seed is
183 * represented, and whether or not the returned hash is 32 bits or 64
184 * bits. 32 bit hashes will return 0 for the minor hash.
186 int ldiskfsfs_dirhash(const char *name, int len, struct ldiskfs_dx_hash_info *hinfo)
189 __u32 minor_hash = 0;
194 /* Initialize the default seed for the hash checksum functions */
200 /* Check to see if the seed is all zero's */
202 for (i=0; i < 4; i++) {
207 memcpy(buf, hinfo->seed, sizeof(buf));
210 switch (hinfo->hash_version) {
211 case LDISKFS_DX_HASH_LEGACY:
212 hash = dx_hack_hash(name, len);
214 case LDISKFS_DX_HASH_HALF_MD4:
217 str2hashbuf(p, len, in, 8);
218 halfMD4Transform(buf, in);
225 case LDISKFS_DX_HASH_TEA:
228 str2hashbuf(p, len, in, 4);
229 TEA_transform(buf, in);
236 case LDISKFS_DX_HASH_R5:
237 hash = dx_r5_hash(name, len);
239 case LDISKFS_DX_HASH_SAME:
240 hash = dx_same_hash(name, len);
247 if (hash == (LDISKFS_HTREE_EOF << 1))
248 hash = (LDISKFS_HTREE_EOF-1) << 1;
250 hinfo->minor_hash = minor_hash;