Hi Michael,
On Tue, May 29, 2012 at 1:23 PM, Michael Walle michael@walle.cc wrote:
Hi Joe,
Am Dienstag 29 Mai 2012, 20:08:26 schrieb Joe Hershberger:
If you can verify that the functionality of the CONFIG_BOOTP_RANDOM_DELAY and CONFIG_CMD_LINK_LOCAL are uneffected, then I'm OK with it.
One thing to note is that the link-local implementation needs to use a MAC seeded random number. That means we can't have other things coming in and seeding it with a time. It is nice that it is separate for that reason. Can you solve that and integrate it with your PRNG?
I'm in a hurry, short answer for now: I thought of sth like this:
static inline void srand_mac(void) { unsigned char enetaddr[6]; unsigned int seed;
/* get our mac */ eth_getenv_enetaddr("ethaddr", enetaddr);
seed = enetaddr[5]; seed |= enetaddr[4] << 8; seed |= enetaddr[3] << 16; seed |= enetaddr[2] << 24;
srand(seed); }
I'm not sure why you are only seeding with the last 4 bytes of the MAC. The original algorithm used all 6 (in its way). You also haven't addressed the issue of isolating the link-local algorithm from other non-MAC-seeded random numbers. The most naive way around it would be to rename the rand() in net to rand_mac() or something like that and not attempt to combine them.
-Joe