xref: /OK3568_Linux_fs/u-boot/net/net_rand.h (revision 4882a59341e53eb6f0b4789bf948001014eff981)
1*4882a593Smuzhiyun /*
2*4882a593Smuzhiyun  *	Copied from LiMon - BOOTP.
3*4882a593Smuzhiyun  *
4*4882a593Smuzhiyun  *	Copyright 1994, 1995, 2000 Neil Russell.
5*4882a593Smuzhiyun  *	(See License)
6*4882a593Smuzhiyun  *	Copyright 2000 Paolo Scaffardi
7*4882a593Smuzhiyun  */
8*4882a593Smuzhiyun 
9*4882a593Smuzhiyun #ifndef __NET_RAND_H__
10*4882a593Smuzhiyun #define __NET_RAND_H__
11*4882a593Smuzhiyun 
12*4882a593Smuzhiyun #include <common.h>
13*4882a593Smuzhiyun 
14*4882a593Smuzhiyun /*
15*4882a593Smuzhiyun  * Return a seed for the PRNG derived from the eth0 MAC address.
16*4882a593Smuzhiyun  */
seed_mac(void)17*4882a593Smuzhiyun static inline unsigned int seed_mac(void)
18*4882a593Smuzhiyun {
19*4882a593Smuzhiyun 	unsigned char enetaddr[ARP_HLEN];
20*4882a593Smuzhiyun 	unsigned int seed;
21*4882a593Smuzhiyun 
22*4882a593Smuzhiyun 	/* get our mac */
23*4882a593Smuzhiyun 	memcpy(enetaddr, eth_get_ethaddr(), ARP_HLEN);
24*4882a593Smuzhiyun 
25*4882a593Smuzhiyun 	seed = enetaddr[5];
26*4882a593Smuzhiyun 	seed ^= enetaddr[4] << 8;
27*4882a593Smuzhiyun 	seed ^= enetaddr[3] << 16;
28*4882a593Smuzhiyun 	seed ^= enetaddr[2] << 24;
29*4882a593Smuzhiyun 	seed ^= enetaddr[1];
30*4882a593Smuzhiyun 	seed ^= enetaddr[0] << 8;
31*4882a593Smuzhiyun 
32*4882a593Smuzhiyun 	return seed;
33*4882a593Smuzhiyun }
34*4882a593Smuzhiyun 
35*4882a593Smuzhiyun /*
36*4882a593Smuzhiyun  * Seed the random number generator using the eth0 MAC address.
37*4882a593Smuzhiyun  */
srand_mac(void)38*4882a593Smuzhiyun static inline void srand_mac(void)
39*4882a593Smuzhiyun {
40*4882a593Smuzhiyun 	srand(seed_mac());
41*4882a593Smuzhiyun }
42*4882a593Smuzhiyun 
43*4882a593Smuzhiyun #endif /* __NET_RAND_H__ */
44