From: Mike Frysinger <vapier@gentoo.org>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH 2/5] net: add helper to generate random mac address
Date: Sun, 1 Apr 2012 15:34:26 -0400 [thread overview]
Message-ID: <201204011534.27331.vapier@gentoo.org> (raw)
In-Reply-To: <1333197516-5138-3-git-send-email-michael@walle.cc>
On Saturday 31 March 2012 08:38:33 Michael Walle wrote:
> --- a/include/net.h
> +++ b/include/net.h
>
> in emergency cases, where you need a working network connection to seti
"seti" -> "set"
> + * Eg. you wan't a rescue boot and don't have a serial port to access
"wan't" -> "want"
> +void eth_random_enetaddr(uchar *enetaddr)
> +{
> + uint32_t rval;
> +
> + srand(get_timer(0));
> + rval = rand();
> +
> + enetaddr[0] = 0x02; /* locally administered */
> + enetaddr[1] = 0x00;
> + enetaddr[2] = 0x00;
> + enetaddr[3] = rval & 0xff;
> + enetaddr[4] = (rval >> 8) & 0xff;
> + enetaddr[5] = (rval >> 16) & 0xff;
why only extract 24 of the 32bits ? and if you add a 2nd rand() call, you
could seed all 48bits easily.
then to make sure the first byte is correct, you finish off with:
/* make sure it's local and unicast */
enetaddr[0] = (enetaddr[0] | 0x02) & ~0x01;
-mike
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next prev parent reply other threads:[~2012-04-01 19:34 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-31 12:38 [U-Boot] [PATCH 0/5 v3] Kirkwood: add lschlv2 and lsxhl board support Michael Walle
2012-03-31 12:38 ` [U-Boot] [PATCH 1/5] lib: add rand() function Michael Walle
2012-03-31 12:38 ` [U-Boot] [PATCH 2/5] net: add helper to generate random mac address Michael Walle
2012-04-01 19:34 ` Mike Frysinger [this message]
2012-04-01 20:00 ` Michael Walle
2012-04-02 5:39 ` Prafulla Wadaskar
2012-03-31 12:38 ` [U-Boot] [PATCH 3/5] net: add eth_setenv_enetaddr_by_index() Michael Walle
2012-04-02 5:42 ` Prafulla Wadaskar
2012-03-31 12:38 ` [U-Boot] [PATCH 4/5] Kirkwood: add lschlv2 and lsxhl board support Michael Walle
2012-03-31 12:38 ` [U-Boot] [PATCH 5/5] Kirkwood: automatically build kwb image for lsxl Michael Walle
2012-04-02 5:24 ` [U-Boot] [PATCH 0/5 v3] Kirkwood: add lschlv2 and lsxhl board support Prafulla Wadaskar
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