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 static void TEA_transform(__u32 buf[4], __u32 const in[])
30 __u32 b0 = buf[0], b1 = buf[1];
31 __u32 a = in[0], b = in[1], c = in[2], d = in[3];
36 b0 += ((b1 << 4)+a) ^ (b1+sum) ^ ((b1 >> 5)+b);
37 b1 += ((b0 << 4)+c) ^ (b0+sum) ^ ((b0 >> 5)+d);
44 /* F, G and H are basic MD4 functions: selection, majority, parity */
45 #define F(x, y, z) ((z) ^ ((x) & ((y) ^ (z))))
46 #define G(x, y, z) (((x) & (y)) + (((x) ^ (y)) & (z)))
47 #define H(x, y, z) ((x) ^ (y) ^ (z))
50 * The generic round function. The application is so specific that
51 * we don't bother protecting all the arguments with parens, as is generally
52 * good macro practice, in favor of extra legibility.
53 * Rotation is separate from addition to prevent recomputation
55 #define ROUND(f, a, b, c, d, x, s) \
56 (a += f(b, c, d) + x, a = (a << s) | (a >> (32-s)))
58 #define K2 013240474631UL
59 #define K3 015666365641UL
62 * Basic cut-down MD4 transform. Returns only 32 bits of result.
64 static void halfMD4Transform (__u32 buf[4], __u32 const in[])
66 __u32 a = buf[0], b = buf[1], c = buf[2], d = buf[3];
69 ROUND(F, a, b, c, d, in[0] + K1, 3);
70 ROUND(F, d, a, b, c, in[1] + K1, 7);
71 ROUND(F, c, d, a, b, in[2] + K1, 11);
72 ROUND(F, b, c, d, a, in[3] + K1, 19);
73 ROUND(F, a, b, c, d, in[4] + K1, 3);
74 ROUND(F, d, a, b, c, in[5] + K1, 7);
75 ROUND(F, c, d, a, b, in[6] + K1, 11);
76 ROUND(F, b, c, d, a, in[7] + K1, 19);
79 ROUND(G, a, b, c, d, in[1] + K2, 3);
80 ROUND(G, d, a, b, c, in[3] + K2, 5);
81 ROUND(G, c, d, a, b, in[5] + K2, 9);
82 ROUND(G, b, c, d, a, in[7] + K2, 13);
83 ROUND(G, a, b, c, d, in[0] + K2, 3);
84 ROUND(G, d, a, b, c, in[2] + K2, 5);
85 ROUND(G, c, d, a, b, in[4] + K2, 9);
86 ROUND(G, b, c, d, a, in[6] + K2, 13);
89 ROUND(H, a, b, c, d, in[3] + K3, 3);
90 ROUND(H, d, a, b, c, in[7] + K3, 9);
91 ROUND(H, c, d, a, b, in[2] + K3, 11);
92 ROUND(H, b, c, d, a, in[6] + K3, 15);
93 ROUND(H, a, b, c, d, in[1] + K3, 3);
94 ROUND(H, d, a, b, c, in[5] + K3, 9);
95 ROUND(H, c, d, a, b, in[0] + K3, 11);
96 ROUND(H, b, c, d, a, in[4] + K3, 15);
112 /* The old legacy hash */
113 static __u32 dx_hack_hash (const char *name, int len)
115 __u32 hash0 = 0x12a3fe2d, hash1 = 0x37abe8f9;
117 __u32 hash = hash1 + (hash0 ^ (*name++ * 7152373));
119 if (hash & 0x80000000) hash -= 0x7fffffff;
126 static __u32 dx_r5_hash(const signed char *msg, int len)
138 static __u32 dx_same_hash(const signed char *msg, int len)
143 static void str2hashbuf(const char *msg, int len, __u32 *buf, int num)
148 pad = (__u32)len | ((__u32)len << 8);
154 for (i=0; i < len; i++) {
157 val = msg[i] + (val << 8);
171 * Returns the hash of a filename. If len is 0 and name is NULL, then
172 * this function can be used to test whether or not a hash version is
175 * The seed is an 4 longword (32 bits) "secret" which can be used to
176 * uniquify a hash. If the seed is all zero's, then some default seed
179 * A particular hash version specifies whether or not the seed is
180 * represented, and whether or not the returned hash is 32 bits or 64
181 * bits. 32 bit hashes will return 0 for the minor hash.
183 int ldiskfsfs_dirhash(const char *name, int len, struct ldiskfs_dx_hash_info *hinfo)
186 __u32 minor_hash = 0;
191 /* Initialize the default seed for the hash checksum functions */
197 /* Check to see if the seed is all zero's */
199 for (i=0; i < 4; i++) {
204 memcpy(buf, hinfo->seed, sizeof(buf));
207 switch (hinfo->hash_version) {
208 case LDISKFS_DX_HASH_LEGACY:
209 hash = dx_hack_hash(name, len);
211 case LDISKFS_DX_HASH_HALF_MD4:
214 str2hashbuf(p, len, in, 8);
215 halfMD4Transform(buf, in);
222 case LDISKFS_DX_HASH_TEA:
225 str2hashbuf(p, len, in, 4);
226 TEA_transform(buf, in);
233 case LDISKFS_DX_HASH_R5:
234 hash = dx_r5_hash(name, len);
236 case LDISKFS_DX_HASH_SAME:
237 hash = dx_same_hash(name, len);
244 if (hash == (LDISKFS_HTREE_EOF << 1))
245 hash = (LDISKFS_HTREE_EOF-1) << 1;
247 hinfo->minor_hash = minor_hash;