openrc/net/apipa.sh

# Copyright (c) 2007-2008 Roy Marples <roy@marples.name>
# All rights reserved. Released under the 2-clause BSD license.

apipa_depend()
{
	program /sbin/arping
}

_random()
{
	local r=${RANDOM}
	if [ -n "${r}" ]; then
		echo "${r}"
	else
		uuidgen | sed -n -e 's/[^[:digit:]]//g' -e 's/\(^.\{1,7\}\).*/\1/p'
	fi
}

apipa_start()
{
	local iface="$1" i1= i2= addr= i=0

	_exists true || return 1

	einfo "Searching for free addresses in 169.254.0.0/16"
	eindent

	while [ ${i} -lt 64516 ]; do
		i1=$((($(_random) % 255) + 1))
		i2=$((($(_random) % 255) + 1))

		addr="169.254.${i1}.${i2}"
		vebegin "${addr}/16"
		if ! arping_address "${addr}"; then
			eval config_${config_index}="\"${addr}/16 broadcast 169.254.255.255\""
			config_index=$((${config_index} - 1))
			veend 0
			eoutdent
			return 0
		fi

		i=$((${i} + 1))
	done

	eerror "No free address found!"
	eoutdent
	return 1
}