Files
DnsServer/DnsServerCore/Dhcp/Scope.cs

1721 lines
61 KiB
C#

/*
Technitium DNS Server
Copyright (C) 2022 Shreyas Zare (shreyas@technitium.com)
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
using DnsServerCore.Dhcp.Options;
using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Net.NetworkInformation;
using System.Net.Sockets;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using TechnitiumLibrary;
using TechnitiumLibrary.IO;
using TechnitiumLibrary.Net;
using TechnitiumLibrary.Net.Dns;
namespace DnsServerCore.Dhcp
{
public sealed class Scope : IComparable<Scope>, IDisposable
{
#region variables
//required parameters
string _name;
bool _enabled;
IPAddress _startingAddress;
IPAddress _endingAddress;
IPAddress _subnetMask;
ushort _leaseTimeDays = 1; //default 1 day lease
byte _leaseTimeHours = 0;
byte _leaseTimeMinutes = 0;
ushort _offerDelayTime;
bool _pingCheckEnabled;
ushort _pingCheckTimeout = 1000;
byte _pingCheckRetries = 2;
//dhcp options
string _domainName;
uint _dnsTtl = 900;
IPAddress _serverAddress;
string _serverHostName;
string _bootFileName;
IPAddress _routerAddress;
bool _useThisDnsServer;
IReadOnlyCollection<IPAddress> _dnsServers;
IReadOnlyCollection<IPAddress> _winsServers;
IReadOnlyCollection<IPAddress> _ntpServers;
IReadOnlyCollection<ClasslessStaticRouteOption.Route> _staticRoutes;
IReadOnlyDictionary<string, VendorSpecificInformationOption> _vendorInfo;
//advanced options
IReadOnlyCollection<Exclusion> _exclusions;
readonly ConcurrentDictionary<ClientIdentifierOption, Lease> _reservedLeases = new ConcurrentDictionary<ClientIdentifierOption, Lease>();
bool _allowOnlyReservedLeases;
//leases
readonly ConcurrentDictionary<ClientIdentifierOption, Lease> _leases = new ConcurrentDictionary<ClientIdentifierOption, Lease>();
//internal computed parameters
IPAddress _networkAddress;
IPAddress _broadcastAddress;
//internal parameters
const int OFFER_EXPIRY_SECONDS = 60; //1 mins offer expiry
readonly ConcurrentDictionary<ClientIdentifierOption, Lease> _offers = new ConcurrentDictionary<ClientIdentifierOption, Lease>();
IPAddress _lastAddressOffered;
readonly SemaphoreSlim _lastAddressOfferedLock = new SemaphoreSlim(1, 1);
IPAddress _interfaceAddress;
int _interfaceIndex;
DateTime _lastModified = DateTime.UtcNow;
#endregion
#region constructor
public Scope(string name, bool enabled, IPAddress startingAddress, IPAddress endingAddress, IPAddress subnetMask)
{
ValidateScopeName(name);
_name = name;
_enabled = enabled;
ChangeNetwork(startingAddress, endingAddress, subnetMask);
}
public Scope(BinaryReader bR)
{
if (Encoding.ASCII.GetString(bR.ReadBytes(2)) != "SC")
throw new InvalidDataException("DhcpServer scope file format is invalid.");
byte version = bR.ReadByte();
switch (version)
{
case 1:
case 2:
case 3:
case 4:
case 5:
_name = bR.ReadShortString();
_enabled = bR.ReadBoolean();
ChangeNetwork(IPAddressExtension.Parse(bR), IPAddressExtension.Parse(bR), IPAddressExtension.Parse(bR));
_leaseTimeDays = bR.ReadUInt16();
_leaseTimeHours = bR.ReadByte();
_leaseTimeMinutes = bR.ReadByte();
_offerDelayTime = bR.ReadUInt16();
if (version >= 5)
{
_pingCheckEnabled = bR.ReadBoolean();
_pingCheckTimeout = bR.ReadUInt16();
_pingCheckRetries = bR.ReadByte();
}
_domainName = bR.ReadShortString();
if (string.IsNullOrWhiteSpace(_domainName))
_domainName = null;
_dnsTtl = bR.ReadUInt32();
if (version >= 2)
{
_serverAddress = IPAddressExtension.Parse(bR);
if (_serverAddress.Equals(IPAddress.Any))
_serverAddress = null;
}
if (version >= 3)
{
_serverHostName = bR.ReadShortString();
if (string.IsNullOrEmpty(_serverHostName))
_serverHostName = null;
_bootFileName = bR.ReadShortString();
if (string.IsNullOrEmpty(_bootFileName))
_bootFileName = null;
}
_routerAddress = IPAddressExtension.Parse(bR);
if (_routerAddress.Equals(IPAddress.Any))
_routerAddress = null;
{
int count = bR.ReadByte();
if (count > 0)
{
if (count == 255)
{
_useThisDnsServer = true;
FindThisDnsServerAddress();
}
else
{
IPAddress[] dnsServers = new IPAddress[count];
for (int i = 0; i < count; i++)
dnsServers[i] = IPAddressExtension.Parse(bR);
_dnsServers = dnsServers;
}
}
}
{
int count = bR.ReadByte();
if (count > 0)
{
IPAddress[] winsServers = new IPAddress[count];
for (int i = 0; i < count; i++)
winsServers[i] = IPAddressExtension.Parse(bR);
_winsServers = winsServers;
}
}
{
int count = bR.ReadByte();
if (count > 0)
{
IPAddress[] ntpServers = new IPAddress[count];
for (int i = 0; i < count; i++)
ntpServers[i] = IPAddressExtension.Parse(bR);
_ntpServers = ntpServers;
}
}
{
int count = bR.ReadByte();
if (count > 0)
{
ClasslessStaticRouteOption.Route[] staticRoutes = new ClasslessStaticRouteOption.Route[count];
for (int i = 0; i < count; i++)
staticRoutes[i] = new ClasslessStaticRouteOption.Route(bR.BaseStream);
_staticRoutes = staticRoutes;
}
}
if (version >= 4)
{
int count = bR.ReadByte();
if (count > 0)
{
Dictionary<string, VendorSpecificInformationOption> vendorInfo = new Dictionary<string, VendorSpecificInformationOption>(count);
for (int i = 0; i < count; i++)
{
string vendorClassIdentifier = bR.ReadShortString();
VendorSpecificInformationOption vendorSpecificInformation = new VendorSpecificInformationOption(bR.ReadBuffer());
vendorInfo.Add(vendorClassIdentifier, vendorSpecificInformation);
}
_vendorInfo = vendorInfo;
}
}
{
int count = bR.ReadByte();
if (count > 0)
{
Exclusion[] exclusions = new Exclusion[count];
for (int i = 0; i < count; i++)
exclusions[i] = new Exclusion(IPAddressExtension.Parse(bR), IPAddressExtension.Parse(bR));
_exclusions = exclusions;
}
}
{
int count = bR.ReadInt32();
if (count > 0)
{
for (int i = 0; i < count; i++)
{
Lease reservedLease = new Lease(bR);
_reservedLeases.TryAdd(reservedLease.ClientIdentifier, reservedLease);
}
}
_allowOnlyReservedLeases = bR.ReadBoolean();
}
{
int count = bR.ReadInt32();
if (count > 0)
{
for (int i = 0; i < count; i++)
{
Lease lease = new Lease(bR);
_leases.TryAdd(lease.ClientIdentifier, lease);
}
}
}
break;
default:
throw new InvalidDataException("Scope data format version not supported.");
}
}
#endregion
#region IDisposable
bool _disposed;
public void Dispose()
{
if (_disposed)
return;
if (_lastAddressOfferedLock is not null)
_lastAddressOfferedLock.Dispose();
_disposed = true;
}
#endregion
#region static
public static void ValidateScopeName(string name)
{
foreach (char invalidChar in Path.GetInvalidFileNameChars())
{
if (name.Contains(invalidChar))
throw new DhcpServerException("The scope name contains an invalid character: " + invalidChar);
}
}
public static bool IsAddressInRange(IPAddress address, IPAddress startingAddress, IPAddress endingAddress)
{
uint addressNumber = address.ConvertIpToNumber();
uint startingAddressNumber = startingAddress.ConvertIpToNumber();
uint endingAddressNumber = endingAddress.ConvertIpToNumber();
return (startingAddressNumber <= addressNumber) && (addressNumber <= endingAddressNumber);
}
#endregion
#region private
private uint GetLeaseTime()
{
return Convert.ToUInt32((_leaseTimeDays * 24 * 60 * 60) + (_leaseTimeHours * 60 * 60) + (_leaseTimeMinutes * 60));
}
private async Task<AddressStatus> IsAddressAvailableAsync(IPAddress address)
{
if (address.Equals(_routerAddress))
return AddressStatus.FALSE;
if ((_dnsServers != null) && _dnsServers.Contains(address))
return AddressStatus.FALSE;
if ((_winsServers != null) && _winsServers.Contains(address))
return AddressStatus.FALSE;
if ((_ntpServers != null) && _ntpServers.Contains(address))
return AddressStatus.FALSE;
if (_exclusions != null)
{
foreach (Exclusion exclusion in _exclusions)
{
if (IsAddressInRange(address, exclusion.StartingAddress, exclusion.EndingAddress))
return new AddressStatus(false, exclusion.EndingAddress);
}
}
foreach (KeyValuePair<ClientIdentifierOption, Lease> reservedLease in _reservedLeases)
{
if (address.Equals(reservedLease.Value.Address))
return AddressStatus.FALSE;
}
foreach (KeyValuePair<ClientIdentifierOption, Lease> lease in _leases)
{
if (address.Equals(lease.Value.Address))
return AddressStatus.FALSE;
}
foreach (KeyValuePair<ClientIdentifierOption, Lease> offer in _offers)
{
if (address.Equals(offer.Value.Address))
return AddressStatus.FALSE;
}
if (_pingCheckEnabled)
{
try
{
using (Ping ping = new Ping())
{
int retry = 0;
do
{
PingReply reply = await ping.SendPingAsync(address, _pingCheckTimeout);
if (reply.Status == IPStatus.Success)
return AddressStatus.FALSE; //address is in use
}
while (++retry < _pingCheckRetries);
}
}
catch
{ }
}
return AddressStatus.TRUE;
}
private bool IsAddressAlreadyAllocated(IPAddress address, ClientIdentifierOption clientIdentifier)
{
foreach (KeyValuePair<ClientIdentifierOption, Lease> lease in _leases)
{
if (address.Equals(lease.Value.Address))
return !lease.Key.Equals(clientIdentifier);
}
foreach (KeyValuePair<ClientIdentifierOption, Lease> offer in _offers)
{
if (address.Equals(offer.Value.Address))
return !offer.Key.Equals(clientIdentifier);
}
return false;
}
private ClientFullyQualifiedDomainNameOption GetClientFullyQualifiedDomainNameOption(DhcpMessage request, string overrideClientDomainName)
{
ClientFullyQualifiedDomainNameFlags responseFlags = ClientFullyQualifiedDomainNameFlags.None;
if (request.ClientFullyQualifiedDomainName.Flags.HasFlag(ClientFullyQualifiedDomainNameFlags.EncodeUsingCanonicalWireFormat))
responseFlags |= ClientFullyQualifiedDomainNameFlags.EncodeUsingCanonicalWireFormat;
if (request.ClientFullyQualifiedDomainName.Flags.HasFlag(ClientFullyQualifiedDomainNameFlags.NoDnsUpdate))
{
responseFlags |= ClientFullyQualifiedDomainNameFlags.ShouldUpdateDns;
responseFlags |= ClientFullyQualifiedDomainNameFlags.OverrideByServer;
}
else if (request.ClientFullyQualifiedDomainName.Flags.HasFlag(ClientFullyQualifiedDomainNameFlags.ShouldUpdateDns))
{
responseFlags |= ClientFullyQualifiedDomainNameFlags.ShouldUpdateDns;
}
else
{
responseFlags |= ClientFullyQualifiedDomainNameFlags.ShouldUpdateDns;
responseFlags |= ClientFullyQualifiedDomainNameFlags.OverrideByServer;
}
string clientDomainName;
if (!string.IsNullOrWhiteSpace(overrideClientDomainName))
{
//domain name override by server
clientDomainName = overrideClientDomainName;
}
else if (string.IsNullOrWhiteSpace(request.ClientFullyQualifiedDomainName.DomainName))
{
//client domain empty and expects server for a fqdn domain name
if (request.HostName == null)
return null; //server unable to decide a name for client
clientDomainName = request.HostName.HostName + "." + _domainName;
}
else if (request.ClientFullyQualifiedDomainName.DomainName.Contains("."))
{
//client domain is fqdn
if (request.ClientFullyQualifiedDomainName.DomainName.EndsWith("." + _domainName, StringComparison.OrdinalIgnoreCase))
{
clientDomainName = request.ClientFullyQualifiedDomainName.DomainName;
}
else
{
string[] parts = request.ClientFullyQualifiedDomainName.DomainName.Split('.');
clientDomainName = parts[0] + "." + _domainName;
}
}
else
{
//client domain is just hostname
clientDomainName = request.ClientFullyQualifiedDomainName.DomainName + "." + _domainName;
}
return new ClientFullyQualifiedDomainNameOption(responseFlags, 255, 255, clientDomainName);
}
private void ConvertToReservedLease(Lease lease)
{
//convert dynamic to reserved lease
lease.ConvertToReserved();
//add reserved lease
Lease reservedLease = new Lease(LeaseType.Reserved, null, DhcpMessageHardwareAddressType.Ethernet, lease.HardwareAddress, lease.Address, null);
_reservedLeases[reservedLease.ClientIdentifier] = reservedLease;
}
private void ConvertToDynamicLease(Lease lease)
{
//convert reserved to dynamic lease
lease.ConvertToDynamic();
//remove reserved lease
Lease reservedLease = new Lease(LeaseType.Reserved, null, DhcpMessageHardwareAddressType.Ethernet, lease.HardwareAddress, lease.Address, null);
_reservedLeases.TryRemove(reservedLease.ClientIdentifier, out _);
//remove any old single address exclusion entry
if (_exclusions != null)
{
foreach (Exclusion exclusion in _exclusions)
{
if (exclusion.StartingAddress.Equals(lease.Address) && exclusion.EndingAddress.Equals(lease.Address))
{
//remove single address exclusion entry
if (_exclusions.Count == 1)
{
_exclusions = null;
}
else
{
List<Exclusion> exclusions = new List<Exclusion>();
foreach (Exclusion exc in _exclusions)
{
if (exc.Equals(exclusion))
continue;
exclusions.Add(exc);
}
_exclusions = exclusions;
}
break;
}
}
}
}
#endregion
#region internal
internal bool FindInterface()
{
//find network with static ip address in scope range
uint networkAddressNumber = _networkAddress.ConvertIpToNumber();
uint subnetMaskNumber = _subnetMask.ConvertIpToNumber();
foreach (NetworkInterface nic in NetworkInterface.GetAllNetworkInterfaces())
{
if (nic.OperationalStatus != OperationalStatus.Up)
continue;
IPInterfaceProperties ipInterface = nic.GetIPProperties();
foreach (UnicastIPAddressInformation ip in ipInterface.UnicastAddresses)
{
if (ip.Address.AddressFamily == AddressFamily.InterNetwork)
{
uint addressNumber = ip.Address.ConvertIpToNumber();
if ((addressNumber & subnetMaskNumber) == networkAddressNumber)
{
//found interface for this scope range
try
{
//check if interface has dynamic ipv4 address assigned via dhcp
foreach (IPAddress dhcpServerAddress in ipInterface.DhcpServerAddresses)
{
if (dhcpServerAddress.AddressFamily == AddressFamily.InterNetwork)
throw new DhcpServerException("DHCP Server requires static IP address to work correctly but the network interface was found to have a dynamic IP address [" + ip.Address.ToString() + "] assigned by another DHCP server: " + dhcpServerAddress.ToString());
}
}
catch (PlatformNotSupportedException)
{
//DhcpServerAddresses() not supported on macOs
//ignore the exception
}
_interfaceAddress = ip.Address;
_interfaceIndex = ipInterface.GetIPv4Properties().Index;
return true;
}
}
}
}
try
{
//check if at least one interface has static ip address
foreach (NetworkInterface nic in NetworkInterface.GetAllNetworkInterfaces())
{
if (nic.OperationalStatus != OperationalStatus.Up)
continue;
IPInterfaceProperties ipInterface = nic.GetIPProperties();
foreach (UnicastIPAddressInformation ip in ipInterface.UnicastAddresses)
{
if (ip.Address.AddressFamily == AddressFamily.InterNetwork)
{
//check if address is static
if (ipInterface.DhcpServerAddresses.Count < 1)
{
//found static ip address so this scope can be activated
//using ANY ip address for this scope interface since we dont know the relay agent network
_interfaceAddress = IPAddress.Any;
_interfaceIndex = -1;
return true;
}
}
}
}
}
catch (PlatformNotSupportedException)
{
//DhcpServerAddresses() not supported on macOs
//ignore the exception
}
//server has no static ip address configured
return false;
}
internal void FindThisDnsServerAddress()
{
NetworkInterface[] networkInterfaces = NetworkInterface.GetAllNetworkInterfaces();
//find interface in current scope network range
uint networkAddressNumber = _networkAddress.ConvertIpToNumber();
uint subnetMaskNumber = _subnetMask.ConvertIpToNumber();
foreach (NetworkInterface nic in networkInterfaces)
{
if (nic.OperationalStatus != OperationalStatus.Up)
continue;
IPInterfaceProperties ipInterface = nic.GetIPProperties();
foreach (UnicastIPAddressInformation ip in ipInterface.UnicastAddresses)
{
if (ip.Address.AddressFamily == AddressFamily.InterNetwork)
{
uint addressNumber = ip.Address.ConvertIpToNumber();
if ((addressNumber & subnetMaskNumber) == networkAddressNumber)
{
//found address in this scope range to use as dns server
_dnsServers = new IPAddress[] { ip.Address };
return;
}
}
}
}
//find unicast ip address on an interface which has gateway
foreach (NetworkInterface nic in networkInterfaces)
{
if (nic.OperationalStatus != OperationalStatus.Up)
continue;
IPInterfaceProperties ipInterface = nic.GetIPProperties();
if (ipInterface.GatewayAddresses.Count > 0)
{
foreach (UnicastIPAddressInformation ip in ipInterface.UnicastAddresses)
{
if (ip.Address.AddressFamily == AddressFamily.InterNetwork)
{
//use this address for dns
_dnsServers = new IPAddress[] { ip.Address };
return;
}
}
}
}
//find any unicast ip address available
foreach (NetworkInterface nic in networkInterfaces)
{
if (nic.OperationalStatus != OperationalStatus.Up)
continue;
IPInterfaceProperties ipInterface = nic.GetIPProperties();
foreach (UnicastIPAddressInformation ip in ipInterface.UnicastAddresses)
{
if (ip.Address.AddressFamily == AddressFamily.InterNetwork)
{
//use this address for dns
_dnsServers = new IPAddress[] { ip.Address };
return;
}
}
}
//no useable address was found
_dnsServers = null;
}
internal bool IsAddressInRange(IPAddress address)
{
return IsAddressInRange(address, _startingAddress, _endingAddress);
}
internal bool IsAddressInNetwork(IPAddress address)
{
uint addressNumber = address.ConvertIpToNumber();
uint networkAddressNumber = _networkAddress.ConvertIpToNumber();
uint broadcastAddressNumber = _broadcastAddress.ConvertIpToNumber();
return (networkAddressNumber < addressNumber) && (addressNumber < broadcastAddressNumber);
}
internal bool IsAddressExcluded(IPAddress address)
{
if (_exclusions != null)
{
foreach (Exclusion exclusion in _exclusions)
{
if (IsAddressInRange(address, exclusion.StartingAddress, exclusion.EndingAddress))
return true;
}
}
return false;
}
internal bool IsAddressReserved(IPAddress address)
{
foreach (KeyValuePair<ClientIdentifierOption, Lease> reservedLease in _reservedLeases)
{
if (address.Equals(reservedLease.Value.Address))
return true;
}
return false;
}
internal Lease GetReservedLease(DhcpMessage request)
{
return GetReservedLease(new ClientIdentifierOption((byte)request.HardwareAddressType, request.ClientHardwareAddress), request.ClientIdentifier);
}
private Lease GetReservedLease(ClientIdentifierOption reservedLeasesClientIdentifier, ClientIdentifierOption clientIdentifier)
{
if (_reservedLeases.TryGetValue(reservedLeasesClientIdentifier, out Lease reservedLease))
{
//reserved address exists
if (IsAddressAlreadyAllocated(reservedLease.Address, clientIdentifier))
return null; //reserved lease address is already allocated so ignore reserved lease
return reservedLease;
}
return null;
}
internal async Task<Lease> GetOfferAsync(DhcpMessage request)
{
if (_leases.TryGetValue(request.ClientIdentifier, out Lease existingLease))
{
//lease already exists
if (existingLease.Type == LeaseType.Reserved)
{
Lease existingReservedLease = GetReservedLease(request);
if ((existingReservedLease is not null) && (existingReservedLease.Address == existingLease.Address))
return existingLease; //return existing reserved lease
//reserved lease address was changed; proceed to offer new lease
}
else
{
//is dynamic lease
if (IsAddressExcluded(existingLease.Address))
{
//remove existing dynamic lease; proceed to offer new lease
ReleaseLease(existingLease);
}
else
{
//return existing dynamic lease
return existingLease;
}
}
}
Lease reservedLease = GetReservedLease(request);
if (reservedLease != null)
{
Lease reservedOffer = new Lease(LeaseType.Reserved, request.ClientIdentifier, null, request.ClientHardwareAddress, reservedLease.Address, null, GetLeaseTime());
_offers[request.ClientIdentifier] = reservedOffer;
return reservedOffer;
}
if (_allowOnlyReservedLeases)
throw new DhcpServerException("DHCP Server failed to offer IP address to " + request.GetClientFullIdentifier() + ": scope allows only reserved lease allocations.");
Lease dummyOffer = new Lease(LeaseType.None, null, null, null, null, null, 0);
Lease existingOffer = _offers.GetOrAdd(request.ClientIdentifier, dummyOffer);
if (dummyOffer != existingOffer)
{
if (existingOffer.Type == LeaseType.None)
return null; //dummy offer so another thread is handling offer; do nothing
//offer already exists
existingOffer.ExtendLease(GetLeaseTime());
return existingOffer;
}
//find offer ip address
IPAddress offerAddress = null;
if (request.RequestedIpAddress != null)
{
//client wish to get this address
IPAddress requestedAddress = request.RequestedIpAddress.Address;
if (IsAddressInRange(requestedAddress))
{
AddressStatus addressStatus = await IsAddressAvailableAsync(requestedAddress);
if (addressStatus.IsAddressAvailable)
offerAddress = requestedAddress;
}
}
if (offerAddress == null)
{
await _lastAddressOfferedLock.WaitAsync();
try
{
//find free address from scope
offerAddress = _lastAddressOffered;
uint endingAddressNumber = _endingAddress.ConvertIpToNumber();
bool offerAddressWasResetFromEnd = false;
while (true)
{
uint nextOfferAddressNumber = offerAddress.ConvertIpToNumber() + 1u;
if (nextOfferAddressNumber > endingAddressNumber)
{
if (offerAddressWasResetFromEnd)
throw new DhcpServerException("DHCP Server failed to offer IP address to " + request.GetClientFullIdentifier() + ": address unavailable due to address pool exhaustion.");
offerAddress = IPAddressExtension.ConvertNumberToIp(_startingAddress.ConvertIpToNumber() - 1u);
offerAddressWasResetFromEnd = true;
continue;
}
offerAddress = IPAddressExtension.ConvertNumberToIp(nextOfferAddressNumber);
AddressStatus addressStatus = await IsAddressAvailableAsync(offerAddress);
if (addressStatus.IsAddressAvailable)
break;
if (addressStatus.NewAddress is not null)
offerAddress = addressStatus.NewAddress;
}
_lastAddressOffered = offerAddress;
}
finally
{
_lastAddressOfferedLock.Release();
}
}
Lease offerLease = new Lease(LeaseType.Dynamic, request.ClientIdentifier, null, request.ClientHardwareAddress, offerAddress, null, GetLeaseTime());
return _offers[request.ClientIdentifier] = offerLease;
}
internal Lease GetExistingLeaseOrOffer(DhcpMessage request)
{
//check for lease offer first since it may have a different IP address to offer
if (_offers.TryGetValue(request.ClientIdentifier, out Lease existingOffer))
return existingOffer;
if (_leases.TryGetValue(request.ClientIdentifier, out Lease existingLease))
return existingLease;
return null;
}
internal List<DhcpOption> GetOptions(DhcpMessage request, IPAddress serverIdentifierAddress, string overrideClientDomainName)
{
List<DhcpOption> options = new List<DhcpOption>();
switch (request.DhcpMessageType.Type)
{
case DhcpMessageType.Discover:
options.Add(new DhcpMessageTypeOption(DhcpMessageType.Offer));
break;
case DhcpMessageType.Request:
case DhcpMessageType.Inform:
options.Add(new DhcpMessageTypeOption(DhcpMessageType.Ack));
break;
default:
return null;
}
options.Add(new ServerIdentifierOption(serverIdentifierAddress));
switch (request.DhcpMessageType.Type)
{
case DhcpMessageType.Discover:
case DhcpMessageType.Request:
uint leaseTime = GetLeaseTime();
options.Add(new IpAddressLeaseTimeOption(leaseTime));
options.Add(new RenewalTimeValueOption(leaseTime / 2));
options.Add(new RebindingTimeValueOption(Convert.ToUInt32(leaseTime * 0.875)));
break;
}
if (request.ParameterRequestList == null)
{
options.Add(new SubnetMaskOption(_subnetMask));
options.Add(new BroadcastAddressOption(_broadcastAddress));
if (!string.IsNullOrEmpty(_domainName))
{
options.Add(new DomainNameOption(_domainName));
if (request.ClientFullyQualifiedDomainName != null)
options.Add(GetClientFullyQualifiedDomainNameOption(request, overrideClientDomainName));
}
if (_routerAddress != null)
options.Add(new RouterOption(new IPAddress[] { _routerAddress }));
if (_dnsServers != null)
options.Add(new DomainNameServerOption(_dnsServers));
if (_winsServers != null)
options.Add(new NetBiosNameServerOption(_winsServers));
if (_ntpServers != null)
options.Add(new NetworkTimeProtocolServersOption(_ntpServers));
if (_staticRoutes != null)
options.Add(new ClasslessStaticRouteOption(_staticRoutes));
}
else
{
foreach (DhcpOptionCode optionCode in request.ParameterRequestList.OptionCodes)
{
switch (optionCode)
{
case DhcpOptionCode.SubnetMask:
options.Add(new SubnetMaskOption(_subnetMask));
options.Add(new BroadcastAddressOption(_broadcastAddress));
break;
case DhcpOptionCode.DomainName:
if (!string.IsNullOrEmpty(_domainName))
{
options.Add(new DomainNameOption(_domainName));
if (request.ClientFullyQualifiedDomainName != null)
options.Add(GetClientFullyQualifiedDomainNameOption(request, overrideClientDomainName));
}
break;
case DhcpOptionCode.Router:
if (_routerAddress != null)
options.Add(new RouterOption(new IPAddress[] { _routerAddress }));
break;
case DhcpOptionCode.DomainNameServer:
if (_dnsServers != null)
options.Add(new DomainNameServerOption(_dnsServers));
break;
case DhcpOptionCode.NetBiosOverTcpIpNameServer:
if (_winsServers != null)
options.Add(new NetBiosNameServerOption(_winsServers));
break;
case DhcpOptionCode.NetworkTimeProtocolServers:
if (_ntpServers != null)
options.Add(new NetworkTimeProtocolServersOption(_ntpServers));
break;
case DhcpOptionCode.ClasslessStaticRoute:
if (_staticRoutes != null)
options.Add(new ClasslessStaticRouteOption(_staticRoutes));
break;
}
}
}
if ((_vendorInfo != null) && (request.VendorClassIdentifier != null))
{
if (_vendorInfo.TryGetValue(request.VendorClassIdentifier.Identifier, out VendorSpecificInformationOption vendorSpecificInformationOption) || _vendorInfo.TryGetValue("", out vendorSpecificInformationOption))
{
options.Add(new VendorClassIdentifierOption(request.VendorClassIdentifier.Identifier));
options.Add(vendorSpecificInformationOption);
}
else
{
string match = "substring(vendor-class-identifier,";
foreach (KeyValuePair<string, VendorSpecificInformationOption> entry in _vendorInfo)
{
if (entry.Key.StartsWith(match))
{
int i = entry.Key.IndexOf(')', match.Length);
if (i < match.Length)
continue;
string[] parts = entry.Key.Substring(match.Length, i - match.Length).Split(',');
if (parts.Length != 2)
continue;
if (!int.TryParse(parts[0], out int startIndex))
continue;
if (!int.TryParse(parts[1], out int length))
continue;
int j = entry.Key.IndexOf("==", i);
if (j < i)
continue;
string value = entry.Key.Substring(j + 2);
value = value.Trim();
value = value.Trim('"');
if (request.VendorClassIdentifier.Identifier.Substring(startIndex, length).Equals(value))
{
options.Add(new VendorClassIdentifierOption(value));
options.Add(entry.Value);
break;
}
}
}
}
}
options.Add(DhcpOption.CreateEndOption());
return options;
}
internal void CommitLease(Lease lease)
{
lease.ExtendLease(GetLeaseTime());
_leases[lease.ClientIdentifier] = lease;
_offers.TryRemove(lease.ClientIdentifier, out _);
_lastModified = DateTime.UtcNow;
}
internal void ReleaseLease(Lease lease)
{
_leases.TryRemove(lease.ClientIdentifier, out _);
_lastModified = DateTime.UtcNow;
}
internal void SetEnabled(bool enabled)
{
_enabled = enabled;
if (!enabled)
{
_interfaceAddress = null;
_interfaceIndex = 0;
}
}
internal void RemoveExpiredOffers()
{
DateTime utcNow = DateTime.UtcNow;
foreach (KeyValuePair<ClientIdentifierOption, Lease> offer in _offers)
{
if (utcNow > offer.Value.LeaseObtained.AddSeconds(OFFER_EXPIRY_SECONDS))
{
//offer expired
_offers.TryRemove(offer.Key, out _);
}
}
}
internal List<Lease> RemoveExpiredLeases()
{
List<Lease> expiredLeases = new List<Lease>();
DateTime utcNow = DateTime.UtcNow;
foreach (KeyValuePair<ClientIdentifierOption, Lease> lease in _leases)
{
if (utcNow > lease.Value.LeaseExpires)
{
//lease expired
if (_leases.TryRemove(lease.Key, out Lease expiredLease))
expiredLeases.Add(expiredLease);
}
}
if (expiredLeases.Count > 0)
_lastModified = DateTime.UtcNow;
return expiredLeases;
}
#endregion
#region public
public void ChangeNetwork(IPAddress startingAddress, IPAddress endingAddress, IPAddress subnetMask)
{
if (startingAddress.AddressFamily != AddressFamily.InterNetwork)
throw new ArgumentException("Address family not supported.", nameof(startingAddress));
if (endingAddress.AddressFamily != AddressFamily.InterNetwork)
throw new ArgumentException("Address family not supported.", nameof(endingAddress));
if (subnetMask.AddressFamily != AddressFamily.InterNetwork)
throw new ArgumentException("Address family not supported.", nameof(subnetMask));
uint startingAddressNumber = startingAddress.ConvertIpToNumber();
uint endingAddressNumber = endingAddress.ConvertIpToNumber();
if (startingAddressNumber >= endingAddressNumber)
throw new ArgumentException("Ending address must be greater than starting address.");
_startingAddress = startingAddress;
_endingAddress = endingAddress;
_subnetMask = subnetMask;
//compute other parameters
uint subnetMaskNumber = _subnetMask.ConvertIpToNumber();
uint networkAddressNumber = startingAddressNumber & subnetMaskNumber;
uint broadcastAddressNumber = networkAddressNumber | ~subnetMaskNumber;
if (networkAddressNumber == startingAddressNumber)
throw new ArgumentException("Starting address cannot be same as the network address.");
if (broadcastAddressNumber == endingAddressNumber)
throw new ArgumentException("Ending address cannot be same as the broadcast address.");
_networkAddress = IPAddressExtension.ConvertNumberToIp(networkAddressNumber);
_broadcastAddress = IPAddressExtension.ConvertNumberToIp(broadcastAddressNumber);
_lastAddressOfferedLock.Wait();
try
{
_lastAddressOffered = IPAddressExtension.ConvertNumberToIp(startingAddressNumber - 1u);
}
finally
{
_lastAddressOfferedLock.Release();
}
}
public Lease RemoveLease(string hardwareAddress)
{
byte[] hardwareAddressBytes = Lease.ParseHardwareAddress(hardwareAddress);
foreach (KeyValuePair<ClientIdentifierOption, Lease> entry in _leases)
{
if (BinaryNumber.Equals(entry.Value.HardwareAddress, hardwareAddressBytes))
return RemoveLease(entry.Key);
}
throw new DhcpServerException("No lease was found for hardware address: " + hardwareAddress);
}
public Lease RemoveLease(ClientIdentifierOption clientIdentifier)
{
if (!_leases.TryRemove(clientIdentifier, out Lease removedLease))
throw new DhcpServerException("No lease was found for client identifier: " + clientIdentifier.ToString());
if (removedLease.Type == LeaseType.Reserved)
{
//remove reserved lease
ClientIdentifierOption reservedLeasesClientIdentifier = new ClientIdentifierOption((byte)DhcpMessageHardwareAddressType.Ethernet, removedLease.HardwareAddress);
if (_reservedLeases.TryGetValue(reservedLeasesClientIdentifier, out Lease existingReservedLease))
{
//remove reserved lease only if the IP addresses match
if (existingReservedLease.Address.Equals(removedLease.Address))
_reservedLeases.TryRemove(reservedLeasesClientIdentifier, out _);
}
}
return removedLease;
}
public void ConvertToReservedLease(string hardwareAddress)
{
byte[] hardwareAddressBytes = Lease.ParseHardwareAddress(hardwareAddress);
foreach (KeyValuePair<ClientIdentifierOption, Lease> entry in _leases)
{
Lease lease = entry.Value;
if ((lease.Type == LeaseType.Dynamic) && BinaryNumber.Equals(lease.HardwareAddress, hardwareAddressBytes))
{
ConvertToReservedLease(lease);
return;
}
}
throw new DhcpServerException("No dynamic lease was found for hardware address: " + hardwareAddress);
}
public void ConvertToReservedLease(ClientIdentifierOption clientIdentifier)
{
if (!_leases.TryGetValue(clientIdentifier, out Lease lease) || (lease.Type != LeaseType.Dynamic))
throw new DhcpServerException("No dynamic lease was found for client identifier: " + clientIdentifier.ToString());
ConvertToReservedLease(lease);
}
public void ConvertToDynamicLease(string hardwareAddress)
{
byte[] hardwareAddressBytes = Lease.ParseHardwareAddress(hardwareAddress);
foreach (KeyValuePair<ClientIdentifierOption, Lease> entry in _leases)
{
Lease lease = entry.Value;
if ((lease.Type == LeaseType.Reserved) && BinaryNumber.Equals(lease.HardwareAddress, hardwareAddressBytes))
{
ConvertToDynamicLease(lease);
return;
}
}
throw new DhcpServerException("No reserved lease was found for hardware address: " + hardwareAddress);
}
public void ConvertToDynamicLease(ClientIdentifierOption clientIdentifier)
{
if (!_leases.TryGetValue(clientIdentifier, out Lease lease) || (lease.Type != LeaseType.Reserved))
throw new DhcpServerException("No reserved lease was found for client identifier: " + clientIdentifier.ToString());
ConvertToDynamicLease(lease);
}
public void WriteTo(BinaryWriter bW)
{
bW.Write(Encoding.ASCII.GetBytes("SC"));
bW.Write((byte)5); //version
bW.WriteShortString(_name);
bW.Write(_enabled);
_startingAddress.WriteTo(bW);
_endingAddress.WriteTo(bW);
_subnetMask.WriteTo(bW);
bW.Write(_leaseTimeDays);
bW.Write(_leaseTimeHours);
bW.Write(_leaseTimeMinutes);
bW.Write(_offerDelayTime);
bW.Write(_pingCheckEnabled);
bW.Write(_pingCheckTimeout);
bW.Write(_pingCheckRetries);
if (string.IsNullOrWhiteSpace(_domainName))
bW.Write((byte)0);
else
bW.WriteShortString(_domainName);
bW.Write(_dnsTtl);
if (_serverAddress == null)
IPAddress.Any.WriteTo(bW);
else
_serverAddress.WriteTo(bW);
if (string.IsNullOrEmpty(_serverHostName))
bW.Write((byte)0);
else
bW.WriteShortString(_serverHostName);
if (string.IsNullOrEmpty(_bootFileName))
bW.Write((byte)0);
else
bW.WriteShortString(_bootFileName);
if (_routerAddress == null)
IPAddress.Any.WriteTo(bW);
else
_routerAddress.WriteTo(bW);
if (_useThisDnsServer)
{
bW.Write((byte)255);
}
else if (_dnsServers == null)
{
bW.Write((byte)0);
}
else
{
bW.Write(Convert.ToByte(_dnsServers.Count));
foreach (IPAddress dnsServer in _dnsServers)
dnsServer.WriteTo(bW);
}
if (_winsServers == null)
{
bW.Write((byte)0);
}
else
{
bW.Write(Convert.ToByte(_winsServers.Count));
foreach (IPAddress winsServer in _winsServers)
winsServer.WriteTo(bW);
}
if (_ntpServers == null)
{
bW.Write((byte)0);
}
else
{
bW.Write(Convert.ToByte(_ntpServers.Count));
foreach (IPAddress ntpServer in _ntpServers)
ntpServer.WriteTo(bW);
}
if (_staticRoutes == null)
{
bW.Write((byte)0);
}
else
{
bW.Write(Convert.ToByte(_staticRoutes.Count));
foreach (ClasslessStaticRouteOption.Route route in _staticRoutes)
route.WriteTo(bW.BaseStream);
}
if (_vendorInfo == null)
{
bW.Write((byte)0);
}
else
{
bW.Write(Convert.ToByte(_vendorInfo.Count));
foreach (KeyValuePair<string, VendorSpecificInformationOption> entry in _vendorInfo)
{
bW.WriteShortString(entry.Key);
bW.WriteBuffer(entry.Value.Information);
}
}
if (_exclusions == null)
{
bW.Write((byte)0);
}
else
{
bW.Write(Convert.ToByte(_exclusions.Count));
foreach (Exclusion exclusion in _exclusions)
{
exclusion.StartingAddress.WriteTo(bW);
exclusion.EndingAddress.WriteTo(bW);
}
}
bW.Write(_reservedLeases.Count);
foreach (KeyValuePair<ClientIdentifierOption, Lease> reservedLease in _reservedLeases)
reservedLease.Value.WriteTo(bW);
bW.Write(_allowOnlyReservedLeases);
{
bW.Write(_leases.Count);
foreach (KeyValuePair<ClientIdentifierOption, Lease> lease in _leases)
lease.Value.WriteTo(bW);
}
}
public override bool Equals(object obj)
{
if (obj is null)
return false;
if (ReferenceEquals(this, obj))
return true;
return Equals(obj as Scope);
}
public bool Equals(Scope other)
{
if (other is null)
return false;
if (!_startingAddress.Equals(other._startingAddress))
return false;
if (!_endingAddress.Equals(other._endingAddress))
return false;
return true;
}
public override int GetHashCode()
{
return HashCode.Combine(_startingAddress, _endingAddress, _subnetMask);
}
public override string ToString()
{
return _name;
}
public int CompareTo(Scope other)
{
return _name.CompareTo(other._name);
}
#endregion
#region properties
public string Name
{
get { return _name; }
set
{
ValidateScopeName(value);
_name = value;
}
}
public bool Enabled
{ get { return _enabled; } }
public IPAddress StartingAddress
{ get { return _startingAddress; } }
public IPAddress EndingAddress
{ get { return _endingAddress; } }
public IPAddress SubnetMask
{ get { return _subnetMask; } }
public ushort LeaseTimeDays
{
get { return _leaseTimeDays; }
set
{
if (value > 999)
throw new ArgumentOutOfRangeException(nameof(LeaseTimeDays), "Lease time in days must be between 0 to 999.");
_leaseTimeDays = value;
}
}
public byte LeaseTimeHours
{
get { return _leaseTimeHours; }
set
{
if (value > 23)
throw new ArgumentOutOfRangeException(nameof(LeaseTimeHours), "Lease time in hours must be between 0 to 23.");
_leaseTimeHours = value;
}
}
public byte LeaseTimeMinutes
{
get { return _leaseTimeMinutes; }
set
{
if (value > 59)
throw new ArgumentOutOfRangeException(nameof(LeaseTimeMinutes), "Lease time in minutes must be between 0 to 59.");
_leaseTimeMinutes = value;
}
}
public ushort OfferDelayTime
{
get { return _offerDelayTime; }
set { _offerDelayTime = value; }
}
public bool PingCheckEnabled
{
get { return _pingCheckEnabled; }
set { _pingCheckEnabled = value; }
}
public ushort PingCheckTimeout
{
get { return _pingCheckTimeout; }
set { _pingCheckTimeout = value; }
}
public byte PingCheckRetries
{
get { return _pingCheckRetries; }
set { _pingCheckRetries = value; }
}
public string DomainName
{
get { return _domainName; }
set
{
if (value != null)
DnsClient.IsDomainNameValid(value, true);
_domainName = value;
}
}
public uint DnsTtl
{
get { return _dnsTtl; }
set { _dnsTtl = value; }
}
public IPAddress ServerAddress
{
get { return _serverAddress; }
set { _serverAddress = value; }
}
public string ServerHostName
{
get { return _serverHostName; }
set
{
if ((value != null) && (value.Length >= 64))
throw new ArgumentException("Server host name cannot exceed 63 bytes.");
_serverHostName = value;
}
}
public string BootFileName
{
get { return _bootFileName; }
set
{
if ((value != null) && (value.Length >= 128))
throw new ArgumentException("Boot file name cannot exceed 127 bytes.");
_bootFileName = value;
}
}
public IPAddress RouterAddress
{
get { return _routerAddress; }
set { _routerAddress = value; }
}
public bool UseThisDnsServer
{
get { return _useThisDnsServer; }
set
{
_useThisDnsServer = value;
if (_useThisDnsServer)
FindThisDnsServerAddress();
}
}
public IReadOnlyCollection<IPAddress> DnsServers
{
get { return _dnsServers; }
set
{
_dnsServers = value;
if ((_dnsServers != null) && _dnsServers.Count > 0)
_useThisDnsServer = false;
}
}
public IReadOnlyCollection<IPAddress> WinsServers
{
get { return _winsServers; }
set { _winsServers = value; }
}
public IReadOnlyCollection<IPAddress> NtpServers
{
get { return _ntpServers; }
set { _ntpServers = value; }
}
public IReadOnlyCollection<ClasslessStaticRouteOption.Route> StaticRoutes
{
get { return _staticRoutes; }
set { _staticRoutes = value; }
}
public IReadOnlyDictionary<string, VendorSpecificInformationOption> VendorInfo
{
get { return _vendorInfo; }
set { _vendorInfo = value; }
}
public IReadOnlyCollection<Exclusion> Exclusions
{
get { return _exclusions; }
set
{
if (value == null)
{
_exclusions = null;
}
else
{
foreach (Exclusion exclusion in value)
{
if (!IsAddressInRange(exclusion.StartingAddress))
throw new ArgumentOutOfRangeException(nameof(Exclusions), "Exclusion starting address must be in scope range.");
if (!IsAddressInRange(exclusion.EndingAddress))
throw new ArgumentOutOfRangeException(nameof(Exclusions), "Exclusion ending address must be in scope range.");
}
_exclusions = value;
}
}
}
public IReadOnlyCollection<Lease> ReservedLeases
{
get
{
List<Lease> leases = new List<Lease>(_reservedLeases.Count);
foreach (KeyValuePair<ClientIdentifierOption, Lease> entry in _reservedLeases)
leases.Add(entry.Value);
leases.Sort();
return leases;
}
set
{
if (value == null)
{
_reservedLeases.Clear();
}
else
{
foreach (Lease reservedLease in value)
{
if (!IsAddressInRange(reservedLease.Address))
throw new ArgumentOutOfRangeException(nameof(ReservedLeases), "Reserved address must be in scope range.");
}
_reservedLeases.Clear();
foreach (Lease reservedLease in value)
_reservedLeases.TryAdd(reservedLease.ClientIdentifier, reservedLease);
}
}
}
public bool AllowOnlyReservedLeases
{
get { return _allowOnlyReservedLeases; }
set { _allowOnlyReservedLeases = value; }
}
public IReadOnlyDictionary<ClientIdentifierOption, Lease> Leases
{ get { return _leases; } }
public IPAddress NetworkAddress
{ get { return _networkAddress; } }
public IPAddress BroadcastAddress
{ get { return _broadcastAddress; } }
public IPAddress InterfaceAddress
{ get { return _interfaceAddress; } }
internal int InterfaceIndex
{ get { return _interfaceIndex; } }
internal DateTime LastModified
{ get { return _lastModified; } }
#endregion
class AddressStatus
{
public static readonly AddressStatus TRUE = new AddressStatus(true, null);
public static readonly AddressStatus FALSE = new AddressStatus(false, null);
public readonly bool IsAddressAvailable;
public readonly IPAddress NewAddress;
public AddressStatus(bool isAddressAvailable, IPAddress newAddress)
{
IsAddressAvailable = isAddressAvailable;
NewAddress = newAddress;
}
}
}
}