2 * IRC - Internet Relay Chat, ircd/random.c
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 1, or (at your option)
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
28 char localkey[9] = RANDOM_SEED;
31 * MD5 transform algorithm, taken from code written by Colin Plumb,
32 * and put into the public domain
34 * Kev: Taken from Ted T'so's /dev/random random.c code and modified to
35 * be slightly simpler. That code is released under a BSD-style copyright
36 * OR under the terms of the GNU Public License, which should be included
37 * at the top of this source file.
39 * record: Cleaned up to work with ircd. RANDOM_TOKEN is defined in
40 * setup.h by the make script; if people start to "guess" your cookies,
41 * consider recompiling your server with a different random token.
44 /* The four core functions - F1 is optimized somewhat */
46 #define F1(x, y, z) (z ^ (x & (y ^ z)))
47 #define F2(x, y, z) F1(z, x, y)
48 #define F3(x, y, z) (x ^ y ^ z)
49 #define F4(x, y, z) (y ^ (x | ~z))
51 /* This is the central step in the MD5 algorithm. */
52 #define MD5STEP(f, w, x, y, z, data, s) \
53 ( w += f(x, y, z) + data, w = w<<s | w>>(32-s), w += x )
56 * The core of the MD5 algorithm, this alters an existing MD5 hash to
57 * reflect the addition of 16 longwords of new data. MD5Update blocks
58 * the data and converts bytes into longwords for this routine.
60 * original comment left in; this used to be called MD5Transform and took
61 * two arguments; I've internalized those arguments, creating the character
62 * array "localkey," which should contain 8 bytes of data. The function also
63 * originally returned nothing; now it returns an unsigned long that is the
64 * random number. It appears to be reallyrandom, so... -Kev
66 * I don't really know what this does. I tried to figure it out and got
67 * a headache. If you know what's good for you, you'll leave this stuff
68 * for the smart people and do something else. -record
70 unsigned int ircrandom(void)
72 unsigned int a, b, c, d;
76 gettimeofday(&tv, NULL);
78 memcpy((void *)in, (void *)localkey, 8);
79 memcpy((void *)(in + 8), (void *)&tv.tv_sec, 4);
80 memcpy((void *)(in + 12), (void *)&tv.tv_usec, 4);
87 MD5STEP(F1, a, b, c, d, (int)in[0] + 0xd76aa478, 7);
88 MD5STEP(F1, d, a, b, c, (int)in[1] + 0xe8c7b756, 12);
89 MD5STEP(F1, c, d, a, b, (int)in[2] + 0x242070db, 17);
90 MD5STEP(F1, b, c, d, a, (int)in[3] + 0xc1bdceee, 22);
91 MD5STEP(F1, a, b, c, d, (int)in[4] + 0xf57c0faf, 7);
92 MD5STEP(F1, d, a, b, c, (int)in[5] + 0x4787c62a, 12);
93 MD5STEP(F1, c, d, a, b, (int)in[6] + 0xa8304613, 17);
94 MD5STEP(F1, b, c, d, a, (int)in[7] + 0xfd469501, 22);
95 MD5STEP(F1, a, b, c, d, (int)in[8] + 0x698098d8, 7);
96 MD5STEP(F1, d, a, b, c, (int)in[9] + 0x8b44f7af, 12);
97 MD5STEP(F1, c, d, a, b, (int)in[10] + 0xffff5bb1, 17);
98 MD5STEP(F1, b, c, d, a, (int)in[11] + 0x895cd7be, 22);
99 MD5STEP(F1, a, b, c, d, (int)in[12] + 0x6b901122, 7);
100 MD5STEP(F1, d, a, b, c, (int)in[13] + 0xfd987193, 12);
101 MD5STEP(F1, c, d, a, b, (int)in[14] + 0xa679438e, 17);
102 MD5STEP(F1, b, c, d, a, (int)in[15] + 0x49b40821, 22);
104 MD5STEP(F2, a, b, c, d, (int)in[1] + 0xf61e2562, 5);
105 MD5STEP(F2, d, a, b, c, (int)in[6] + 0xc040b340, 9);
106 MD5STEP(F2, c, d, a, b, (int)in[11] + 0x265e5a51, 14);
107 MD5STEP(F2, b, c, d, a, (int)in[0] + 0xe9b6c7aa, 20);
108 MD5STEP(F2, a, b, c, d, (int)in[5] + 0xd62f105d, 5);
109 MD5STEP(F2, d, a, b, c, (int)in[10] + 0x02441453, 9);
110 MD5STEP(F2, c, d, a, b, (int)in[15] + 0xd8a1e681, 14);
111 MD5STEP(F2, b, c, d, a, (int)in[4] + 0xe7d3fbc8, 20);
112 MD5STEP(F2, a, b, c, d, (int)in[9] + 0x21e1cde6, 5);
113 MD5STEP(F2, d, a, b, c, (int)in[14] + 0xc33707d6, 9);
114 MD5STEP(F2, c, d, a, b, (int)in[3] + 0xf4d50d87, 14);
115 MD5STEP(F2, b, c, d, a, (int)in[8] + 0x455a14ed, 20);
116 MD5STEP(F2, a, b, c, d, (int)in[13] + 0xa9e3e905, 5);
117 MD5STEP(F2, d, a, b, c, (int)in[2] + 0xfcefa3f8, 9);
118 MD5STEP(F2, c, d, a, b, (int)in[7] + 0x676f02d9, 14);
119 MD5STEP(F2, b, c, d, a, (int)in[12] + 0x8d2a4c8a, 20);
121 MD5STEP(F3, a, b, c, d, (int)in[5] + 0xfffa3942, 4);
122 MD5STEP(F3, d, a, b, c, (int)in[8] + 0x8771f681, 11);
123 MD5STEP(F3, c, d, a, b, (int)in[11] + 0x6d9d6122, 16);
124 MD5STEP(F3, b, c, d, a, (int)in[14] + 0xfde5380c, 23);
125 MD5STEP(F3, a, b, c, d, (int)in[1] + 0xa4beea44, 4);
126 MD5STEP(F3, d, a, b, c, (int)in[4] + 0x4bdecfa9, 11);
127 MD5STEP(F3, c, d, a, b, (int)in[7] + 0xf6bb4b60, 16);
128 MD5STEP(F3, b, c, d, a, (int)in[10] + 0xbebfbc70, 23);
129 MD5STEP(F3, a, b, c, d, (int)in[13] + 0x289b7ec6, 4);
130 MD5STEP(F3, d, a, b, c, (int)in[0] + 0xeaa127fa, 11);
131 MD5STEP(F3, c, d, a, b, (int)in[3] + 0xd4ef3085, 16);
132 MD5STEP(F3, b, c, d, a, (int)in[6] + 0x04881d05, 23);
133 MD5STEP(F3, a, b, c, d, (int)in[9] + 0xd9d4d039, 4);
134 MD5STEP(F3, d, a, b, c, (int)in[12] + 0xe6db99e5, 11);
135 MD5STEP(F3, c, d, a, b, (int)in[15] + 0x1fa27cf8, 16);
136 MD5STEP(F3, b, c, d, a, (int)in[2] + 0xc4ac5665, 23);
138 MD5STEP(F4, a, b, c, d, (int)in[0] + 0xf4292244, 6);
139 MD5STEP(F4, d, a, b, c, (int)in[7] + 0x432aff97, 10);
140 MD5STEP(F4, c, d, a, b, (int)in[14] + 0xab9423a7, 15);
141 MD5STEP(F4, b, c, d, a, (int)in[5] + 0xfc93a039, 21);
142 MD5STEP(F4, a, b, c, d, (int)in[12] + 0x655b59c3, 6);
143 MD5STEP(F4, d, a, b, c, (int)in[3] + 0x8f0ccc92, 10);
144 MD5STEP(F4, c, d, a, b, (int)in[10] + 0xffeff47d, 15);
145 MD5STEP(F4, b, c, d, a, (int)in[1] + 0x85845dd1, 21);
146 MD5STEP(F4, a, b, c, d, (int)in[8] + 0x6fa87e4f, 6);
147 MD5STEP(F4, d, a, b, c, (int)in[15] + 0xfe2ce6e0, 10);
148 MD5STEP(F4, c, d, a, b, (int)in[6] + 0xa3014314, 15);
149 MD5STEP(F4, b, c, d, a, (int)in[13] + 0x4e0811a1, 21);
150 MD5STEP(F4, a, b, c, d, (int)in[4] + 0xf7537e82, 6);
151 MD5STEP(F4, d, a, b, c, (int)in[11] + 0xbd3af235, 10);
152 MD5STEP(F4, c, d, a, b, (int)in[2] + 0x2ad7d2bb, 15);
153 MD5STEP(F4, b, c, d, a, (int)in[9] + 0xeb86d391, 21);
156 * We have 4 unsigned longs generated by the above sequence; this scrambles
157 * them together so that if there is any pattern, it will be obscured.
159 return (a ^ b ^ c ^ d);