/// <summary>
/// Calculates all possible subnets in the (address block + cidr) and returns one not being used at the moment.
/// </summary>
private async Task <string> InternalGetRange(string addressBlock, byte cidr, string tableName, string vpcName)
{
if (cidr < 16 || cidr > 28)
{
throw new ArgumentOutOfRangeException(nameof(cidr), "Cidr must be between /16 and /28");
}
var network = IPNetwork.Parse(addressBlock);
var subnets = network.Subnet(cidr);
var numberOfPossibleSubnets = (int)subnets.Count;
IPNetwork validSubnet = null;
NetworkRange networkRange = null;
var count = 0;
var storedRanges = await GetRangesForVpc(vpcName, tableName);
do
{
count++;
var possibleSubnet = subnets[_random.Next(numberOfPossibleSubnets)];
networkRange = new NetworkRange
{
AddressRange = possibleSubnet.ToString(),
VpcName = vpcName
};
if (CanUseRange(storedRanges, possibleSubnet))
{
validSubnet = possibleSubnet;
}
} while (validSubnet == null && count < numberOfPossibleSubnets);
if (validSubnet == null)
{
throw new Exception("No available ranges for this address block");
}
await _context.SaveAsync(networkRange, new DynamoDBOperationConfig { OverrideTableName = tableName });
return(networkRange.AddressRange);
}
public bool Equals(NetworkRange other) => other != null && AddressRange == other.AddressRange && VpcName == other.VpcName;