SLAAC

With IPv6 a host on a network can use StateLess Address AutoConfiguration (SLAAC) to configure it’s network.

Routers will send out Router Advertisements telling the network which subnet is used in the network.

Based on their MAC address (modified EUI-64) a host will then obtain a IPv6 it will use.

Java

For the Apache CloudStack project I had to write Java code which would take a subnet and a MAC address as an argument and would generate a IPv6 SLAAC address from it.

Combining subnet 2001:db8:100::/64 with MAC address 06:7a:88:00:00:8b yields IPv6 address 2001:db8:100:0:47a:88ff:fe00:8b.

/*
 * Java code using Java-ipv6 from Google Code to convert
 * a given IPv6 subnet and a MAC address into a IPv6 address
 * calculated using SLAAC.
 *
 * Author: Wido den Hollander 
*/
import com.googlecode.ipv6.IPv6Address;
import com.googlecode.ipv6.IPv6Network;

public class IPv6EUI64 {
    public static IPv6Address EUI64Address(final IPv6Network cidr, final String macAddress) {
        if (cidr.getNetmask().asPrefixLength() > 64) {
            throw new IllegalArgumentException("IPv6 subnet " + cidr.toString() + " is not 64 bits or larger in size");
        }

        String mac[] = macAddress.toLowerCase().split(":");

        return IPv6Address.fromString(cidr.getFirst().toString() +
                Integer.toHexString(Integer.parseInt(mac[0], 16) ^ 2) +
                mac[1] + ":" + mac[2] + "ff:fe" + mac[3] +":" + mac[4] + mac[5]);
    }

    public static void main(String[] argv) {
        IPv6Network cidr = IPv6Network.fromString("2001:db8:100::/64");
        String mac = "06:7a:88:00:00:8b";
        IPv6Address eui64addr = EUI64Address(cidr, mac);

        /* This will print 2001:db8:100:0:47a:88ff:fe00:8b */
        System.out.println(eui64addr);
    }
}

The code can also be found on my Github Gist page.

After 5 years of great service it was time to replace my Soekris net5501-70 by a new net6501-70.

I tried to install Ubuntu 14.04 via USB, but the Soekris wouldn’t boot from my Kingston Datatraveler USB stick.

It seems the Soekris is rather picky on the USB stick. This is what you don’t want to see:

comBIOS ver. 1.41c  20121115  Copyright (C) 2000-2011 Soekris Engineering.

net6501

2048 Mbyte Memory                        CPU Atom E6xx 1600 Mhz 


SATA AHCI BIOS ver. 0.61 20121115  Copyright (C) 2003-2011 Intel Corporation

Controller Bus#02, Device#06, Function#00: 02 Ports, 02 Devices
  Port-00: Hard Disk, INTEL SSDMCEAC060B3            
  Port-01: Hard Disk, WDC WD10JPVX-80JC3T0           

Soekris USB Expansion ROM ver. 1.01  20111203

82: USB 01                          Xlt -2-32   Mbyte

At 82 you see the USB stick isn’t properly discovered. This is what it should look like:

Soekris USB Expansion ROM ver. 1.01  20111203

82: USB 01  General UDisk           Xlt 994-255-63  7988 Mbyte

That shows t he USB stick is detected properly and you can now install Ubuntu! Simply dd a ISO to the USB stick.

I’ve seen various posts from users on forums asking how you should format your USB devices for usage in your Tesla Model S.

It all depends on the filesystem you are using. This is what I found out:

Working filesystems:

• EXT2
• EXT3
• EXT4
• FAT16
• FAT32

Not Working filesystems:

• exFAT
• NTFS

The Model S is running a modified version of Linux and it seem that it supports all the filesystems which are supported by the Linux kernel natively. I haven’t tested all filesystems, but it probably supports most filesystems available in the kernel.

For large USB devices I recommend using EXT4 and you can access EXT filesystems under Windows using Ext2Fsd.