Exemple #1
0
// convert the ip into the position in the subnet.  Only
// position are saved in the set
func getPosition(address *net.IPNet, ip *net.IP) int32 {
	var (
		first, _ = networkdriver.NetworkRange(address)
		base     = ipToInt(&first)
		i        = ipToInt(ip)
	)
	return i - base
}
// return an available ip if one is currently available.  If not,
// return the next available ip for the nextwork
func getNextIp(address *net.IPNet) (*net.IP, error) {
	var (
		ownIP     = ipToInt(&address.IP)
		available = availableIPS[address.String()]
		allocated = allocatedIPs[address.String()]
		first, _  = networkdriver.NetworkRange(address)
		base      = ipToInt(&first)
		size      = int(networkdriver.NetworkSize(address.Mask))
		max       = int32(size - 2) // size -1 for the broadcast address, -1 for the gateway address
		pos       = int32(available.Pop())
	)

	// We pop and push the position not the ip
	if pos != 0 {
		ip := intToIP(int32(base + pos))
		allocated.Push(int(pos))

		return ip, nil
	}

	var (
		firstNetIP = address.IP.To4().Mask(address.Mask)
		firstAsInt = ipToInt(&firstNetIP) + 1
	)

	pos = int32(allocated.PullBack())
	for i := int32(0); i < max; i++ {
		pos = pos%max + 1
		next := int32(base + pos)

		if next == ownIP || next == firstAsInt {
			continue
		}

		if !allocated.Exists(int(pos)) {
			ip := intToIP(next)
			allocated.Push(int(pos))
			return ip, nil
		}
	}
	return nil, ErrNoAvailableIPs
}