random-eui64

Simple program for generating a locally-administered EUI, following the rules given in IEEE 802, section 8.2.

A random EUI-64 may be useful for experimenters who are prototyping devices, and don't have access to a pool of globally-administered addresses.

You'll have to judge whether you want to use a random ID. However, the definition of EUI-64 allows for this.

Section 8.2 describes the u/l bit (bit 1) of byte 0 of EUI-64. If you set that bit, you have a "locally administered address". Bit 0 always has to be zero for addresses. So a legitimate way of generating a random address, with very low probability of collision, is to generate 8 random bytes, then set bit 1 of byte 0, clear bit 0 of byte 0. On Ubuntu, this simple program will do what you need.

random-eui64 uses data from /dev/random to generate a suitable random address and prints it out in the canonical format. Becuase it uses /dev/random, it may delay indefinitely if your system doesn't have enough available entropy.

Example:

$ random-eui64
4E-D9-09-C5-5E-57-B9-F6

Command-line Options

This program is useful enough to merit a few options.

-eui48 causes it to generate a random 48-bit EUI rather than a 64-bit EUI. -eui64 overrides this and restores the default.

-colon causes the hex bytes of the address to be separated by ':' characters. -dash overrides this, and causes the hex bytes to be separated by '-' characters.

Building

There's no makefile, but the default rules of make can be used.

$ make random-eui64
cc     random-eui64.c   -o random-eui64