func (*AddressSuite) TestDecimalToIPv4(c *gc.C) {
addr := network.DecimalToIPv4(uint32(0))
c.Assert(addr.String(), gc.Equals, "0.0.0.0")
addr = network.DecimalToIPv4(uint32(3232235777))
c.Assert(addr.String(), gc.Equals, "192.168.1.1")
}
// attemptToPickNewAddress will try to pick a new address. It can fail
// with AlreadyExists due to a race condition between fetching the
// list of addresses already in use and allocating a new one. If the
// subnet is not alive, it will also fail. It is called in a loop by
// PickNewAddress until it gets one or there are no more available!
func (s *Subnet) attemptToPickNewAddress() (*IPAddress, error) {
if s.doc.Life != Alive {
return nil, errors.Errorf("cannot pick address: subnet %q is not alive", s)
}
high := s.doc.AllocatableIPHigh
low := s.doc.AllocatableIPLow
if low == "" || high == "" {
return nil, errors.Errorf("no allocatable IP addresses for subnet %q", s)
}
// convert low and high to decimals as the bounds
lowDecimal, err := network.IPv4ToDecimal(net.ParseIP(low))
if err != nil {
// these addresses are validated so should never happen
return nil, errors.Annotatef(err, "invalid AllocatableIPLow %q for subnet %q", low, s)
}
highDecimal, err := network.IPv4ToDecimal(net.ParseIP(high))
if err != nil {
// these addresses are validated so should never happen
return nil, errors.Annotatef(err, "invalid AllocatableIPHigh %q for subnet %q", high, s)
}
// find all addresses for this subnet and convert them to decimals
addresses, closer := s.st.getCollection(ipaddressesC)
defer closer()
id := s.ID()
var doc struct {
Value string
}
allocated := make(map[uint32]bool)
iter := addresses.Find(bson.D{{"subnetid", id}}).Iter()
for iter.Next(&doc) {
// skip invalid values. Can't happen anyway as we validate.
value, err := network.IPv4ToDecimal(net.ParseIP(doc.Value))
if err != nil {
continue
}
allocated[value] = true
}
if err := iter.Close(); err != nil {
return nil, errors.Annotatef(err, "cannot read addresses of subnet %q", s)
}
// Check that the number of addresses in use is less than the
// difference between low and high - i.e. we haven't exhausted all
// possible addresses.
if len(allocated) >= int(highDecimal-lowDecimal)+1 {
return nil, errors.Errorf("allocatable IP addresses exhausted for subnet %q", s)
}
// pick a new random decimal between the low and high bounds that
// doesn't match an existing one
newDecimal := pickAddress(lowDecimal, highDecimal, allocated)
// convert it back to a dotted-quad
newIP := network.DecimalToIPv4(newDecimal)
newAddr := network.NewAddress(newIP.String())
// and create a new IPAddress from it and return it
return s.st.AddIPAddress(newAddr, s.ID())
}