1: /*
2: * libnet
3: * libnet_prand.c - pseudo-random number generation
4: *
5: * Copyright (c) 1998 - 2004 Mike D. Schiffman <mike@infonexus.com>
6: * All rights reserved.
7: *
8: * Redistribution and use in source and binary forms, with or without
9: * modification, are permitted provided that the following conditions
10: * are met:
11: * 1. Redistributions of source code must retain the above copyright
12: * notice, this list of conditions and the following disclaimer.
13: * 2. Redistributions in binary form must reproduce the above copyright
14: * notice, this list of conditions and the following disclaimer in the
15: * documentation and/or other materials provided with the distribution.
16: *
17: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20: * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27: * SUCH DAMAGE.
28: *
29: */
30:
31: #include "common.h"
32:
33: #ifdef _WIN32
34: #include <wincrypt.h>
35: #include <time.h>
36:
37: #else
38: #include <sys/time.h> /* gettimeofday() */
39: #endif
40:
41:
42: int
43: libnet_seed_prand(libnet_t *l)
44: {
45: #ifndef WIN32
46: struct timeval seed;
47: #endif
48:
49: if (l == NULL)
50: {
51: return (-1);
52: }
53:
54: #ifdef WIN32
55: srand((unsigned)time(NULL));
56: #else
57: if (gettimeofday(&seed, NULL) == -1)
58: {
59: snprintf(l->err_buf, LIBNET_ERRBUF_SIZE,
60: "%s(): cannot gettimeofday", __func__);
61: return (-1);
62: }
63:
64: /*
65: * More entropy then just seeding with time(2).
66: */
67: srandom((unsigned)(seed.tv_sec ^ seed.tv_usec));
68: #endif
69: return (1);
70: }
71:
72: /* FIXME this code makes no sense. On unix we use random(), which
73: * is intended to have no security, and under win32 we use cryptographically
74: * strong entropy source? If necessary, why aren't we using /dev/random
75: * on unix? What's going on here?
76: */
77: uint32_t
78: libnet_get_prand(int mod)
79: {
80: uint32_t n; /* 0 to 4,294,967,295 */
81: #ifndef WIN32
82: n = random();
83: #else
84: HCRYPTPROV hProv = 0;
85:
86: CryptAcquireContext(&hProv,
87: 0, 0, PROV_RSA_FULL, CRYPT_VERIFYCONTEXT);
88:
89: CryptGenRandom(hProv, sizeof(n), (BYTE*)&n);
90: CryptReleaseContext(hProv, 0);
91: #endif
92: switch (mod)
93: {
94: case LIBNET_PR2:
95: return (n & 0x1); /* 0 - 1 */
96: case LIBNET_PR8:
97: return (n & 0xff); /* 0 - 255 */
98: case LIBNET_PR16:
99: return (n & 0x7fff); /* 0 - 32767 */
100: case LIBNET_PRu16:
101: return (n & 0xffff); /* 0 - 65535 */
102: case LIBNET_PR32:
103: return (n & 0x7fffffff); /* 0 - 2147483647 */
104: case LIBNET_PRu32:
105: return (n); /* 0 - 4294967295 */
106: }
107: return (0); /* NOTTREACHED */
108: }
109:
110: /**
111: * Local Variables:
112: * indent-tabs-mode: nil
113: * c-file-style: "stroustrup"
114: * End:
115: */
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