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net: Move common init into a new eth_common.c file
[people/ms/u-boot.git] / net / net_rand.h
1 /*
2 * Copied from LiMon - BOOTP.
3 *
4 * Copyright 1994, 1995, 2000 Neil Russell.
5 * (See License)
6 * Copyright 2000 Paolo Scaffardi
7 */
8
9 #ifndef __NET_RAND_H__
10 #define __NET_RAND_H__
11
12 #include <common.h>
13
14 /*
15 * Return a seed for the PRNG derived from the eth0 MAC address.
16 */
17 static inline unsigned int seed_mac(void)
18 {
19 unsigned char enetaddr[6];
20 unsigned int seed;
21
22 /* get our mac */
23 eth_getenv_enetaddr("ethaddr", enetaddr);
24
25 seed = enetaddr[5];
26 seed ^= enetaddr[4] << 8;
27 seed ^= enetaddr[3] << 16;
28 seed ^= enetaddr[2] << 24;
29 seed ^= enetaddr[1];
30 seed ^= enetaddr[0] << 8;
31
32 return seed;
33 }
34
35 /*
36 * Seed the random number generator using the eth0 MAC address.
37 */
38 static inline void srand_mac(void)
39 {
40 srand(seed_mac());
41 }
42
43 #endif /* __NET_RAND_H__ */