private bool IsAddressAlreadyAllocated(Lease reservedLease)
{
foreach (KeyValuePair <ClientIdentifierOption, Lease> lease in _leases)
{
if (reservedLease.Address.Equals(lease.Value.Address))
{
return(!lease.Key.Equals(reservedLease.ClientIdentifier));
}
}
foreach (KeyValuePair <ClientIdentifierOption, Lease> offer in _offers)
{
if (reservedLease.Address.Equals(offer.Value.Address))
{
return(!offer.Key.Equals(reservedLease.ClientIdentifier));
}
}
return(false);
}
private void UpdateDnsAuthZone(bool add, Scope scope, Lease lease)
{
if (_authZoneManager == null)
{
return;
}
if (string.IsNullOrWhiteSpace(scope.DomainName))
{
return;
}
if (string.IsNullOrWhiteSpace(lease.HostName))
{
return;
}
if (!DnsClient.IsDomainNameValid(lease.HostName))
{
return;
}
if (add)
{
//update forward zone
_authZoneManager.CreatePrimaryZone(scope.DomainName, _authZoneManager.ServerDomain, false);
_authZoneManager.SetRecords(lease.HostName, DnsResourceRecordType.A, scope.DnsTtl, new DnsResourceRecordData[] { new DnsARecord(lease.Address) });
//update reverse zone
_authZoneManager.CreatePrimaryZone(scope.ReverseZone, _authZoneManager.ServerDomain, false);
_authZoneManager.SetRecords(Zone.GetReverseZone(lease.Address, 32), DnsResourceRecordType.PTR, scope.DnsTtl, new DnsResourceRecordData[] { new DnsPTRRecord(lease.HostName) });
}
else
{
//remove from forward zone
_authZoneManager.DeleteRecords(lease.HostName, DnsResourceRecordType.A);
//remove from reverse zone
_authZoneManager.DeleteRecords(Zone.GetReverseZone(lease.Address, 32), DnsResourceRecordType.PTR);
}
}
private DhcpMessage ProcessDhcpMessage(DhcpMessage request, IPEndPoint remoteEP, IPPacketInformation ipPacketInformation)
{
if (request.OpCode != DhcpMessageOpCode.BootRequest)
{
return(null);
}
switch (request.DhcpMessageType?.Type)
{
case DhcpMessageType.Discover:
{
Scope scope = FindScope(request, remoteEP.Address, ipPacketInformation);
if (scope == null)
{
return(null); //no scope available; do nothing
}
if (scope.OfferDelayTime > 0)
{
Thread.Sleep(scope.OfferDelayTime); //delay sending offer
}
Lease offer = scope.GetOffer(request);
if (offer == null)
{
throw new DhcpServerException("DHCP Server failed to offer address: address unavailable due to address pool exhaustion.");
}
List <DhcpOption> options = scope.GetOptions(request, scope.InterfaceAddress);
if (options == null)
{
return(null);
}
//log ip offer
LogManager log = _log;
if (log != null)
{
log.Write(remoteEP as IPEndPoint, "DHCP Server offered IP address [" + offer.Address.ToString() + "] to " + request.GetClientFullIdentifier() + ".");
}
return(new DhcpMessage(request, offer.Address, scope.InterfaceAddress, options));
}
case DhcpMessageType.Request:
{
//request ip address lease or extend existing lease
Scope scope = FindScope(request, remoteEP.Address, ipPacketInformation);
if (scope == null)
{
return(null); //no scope available; do nothing
}
Lease leaseOffer;
if (request.ServerIdentifier == null)
{
if (request.RequestedIpAddress == null)
{
//renewing or rebinding
if (request.ClientIpAddress.Equals(IPAddress.Any))
{
return(null); //client must set IP address in ciaddr; do nothing
}
leaseOffer = scope.GetExistingLeaseOrOffer(request);
if (leaseOffer == null)
{
//no existing lease or offer available for client
//send nak
return(new DhcpMessage(request, IPAddress.Any, scope.InterfaceAddress, new DhcpOption[] { new DhcpMessageTypeOption(DhcpMessageType.Nak), new ServerIdentifierOption(scope.InterfaceAddress), DhcpOption.CreateEndOption() }));
}
if (!request.ClientIpAddress.Equals(leaseOffer.Address))
{
//client ip is incorrect
//send nak
return(new DhcpMessage(request, IPAddress.Any, scope.InterfaceAddress, new DhcpOption[] { new DhcpMessageTypeOption(DhcpMessageType.Nak), new ServerIdentifierOption(scope.InterfaceAddress), DhcpOption.CreateEndOption() }));
}
}
else
{
//init-reboot
leaseOffer = scope.GetExistingLeaseOrOffer(request);
if (leaseOffer == null)
{
//no existing lease or offer available for client
//send nak
return(new DhcpMessage(request, IPAddress.Any, scope.InterfaceAddress, new DhcpOption[] { new DhcpMessageTypeOption(DhcpMessageType.Nak), new ServerIdentifierOption(scope.InterfaceAddress), DhcpOption.CreateEndOption() }));
}
if (!request.RequestedIpAddress.Address.Equals(leaseOffer.Address))
{
//the client's notion of its IP address is not correct - RFC 2131
//send nak
return(new DhcpMessage(request, IPAddress.Any, scope.InterfaceAddress, new DhcpOption[] { new DhcpMessageTypeOption(DhcpMessageType.Nak), new ServerIdentifierOption(scope.InterfaceAddress), DhcpOption.CreateEndOption() }));
}
}
}
else
{
//selecting offer
if (request.RequestedIpAddress == null)
{
return(null); //client MUST include this option; do nothing
}
if (!request.ServerIdentifier.Address.Equals(scope.InterfaceAddress))
{
return(null); //offer declined by client; do nothing
}
leaseOffer = scope.GetExistingLeaseOrOffer(request);
if (leaseOffer == null)
{
//no existing lease or offer available for client
//send nak
return(new DhcpMessage(request, IPAddress.Any, scope.InterfaceAddress, new DhcpOption[] { new DhcpMessageTypeOption(DhcpMessageType.Nak), new ServerIdentifierOption(scope.InterfaceAddress), DhcpOption.CreateEndOption() }));
}
if (!request.RequestedIpAddress.Address.Equals(leaseOffer.Address))
{
//requested ip is incorrect
//send nak
return(new DhcpMessage(request, IPAddress.Any, scope.InterfaceAddress, new DhcpOption[] { new DhcpMessageTypeOption(DhcpMessageType.Nak), new ServerIdentifierOption(scope.InterfaceAddress), DhcpOption.CreateEndOption() }));
}
}
List <DhcpOption> options = scope.GetOptions(request, scope.InterfaceAddress);
if (options == null)
{
return(null);
}
scope.CommitLease(leaseOffer);
//log ip lease
LogManager log = _log;
if (log != null)
{
log.Write(remoteEP as IPEndPoint, "DHCP Server leased IP address [" + leaseOffer.Address.ToString() + "] to " + request.GetClientFullIdentifier() + ".");
}
if (!string.IsNullOrEmpty(scope.DomainName))
{
//update dns
string clientDomainName = null;
foreach (DhcpOption option in options)
{
if (option.Code == DhcpOptionCode.ClientFullyQualifiedDomainName)
{
clientDomainName = (option as ClientFullyQualifiedDomainNameOption).DomainName;
break;
}
}
if (clientDomainName == null)
{
if (request.HostName != null)
{
clientDomainName = request.HostName.HostName + "." + scope.DomainName;
}
else if ((leaseOffer.Type == LeaseType.Reserved) && !string.IsNullOrEmpty(leaseOffer.HostName) && !leaseOffer.HostName.EndsWith("." + scope.DomainName, StringComparison.OrdinalIgnoreCase))
{
clientDomainName = leaseOffer.HostName + "." + scope.DomainName; //use hostname from reserved lease
}
}
if (clientDomainName != null)
{
leaseOffer.SetHostName(clientDomainName.ToLower());
UpdateDnsAuthZone(true, scope, leaseOffer);
}
}
return(new DhcpMessage(request, leaseOffer.Address, scope.InterfaceAddress, options));
}
case DhcpMessageType.Decline:
{
//ip address is already in use as detected by client via ARP
if ((request.ServerIdentifier == null) || (request.RequestedIpAddress == null))
{
return(null); //client MUST include these option; do nothing
}
Scope scope = FindScope(request, remoteEP.Address, ipPacketInformation);
if (scope == null)
{
return(null); //no scope available; do nothing
}
if (!request.ServerIdentifier.Address.Equals(scope.InterfaceAddress))
{
return(null); //request not for this server; do nothing
}
Lease lease = scope.GetExistingLeaseOrOffer(request);
if (lease == null)
{
return(null); //no existing lease or offer available for client; do nothing
}
if (!lease.Address.Equals(request.RequestedIpAddress.Address))
{
return(null); //the client's notion of its IP address is not correct; do nothing
}
//remove lease since the IP address is used by someone else
scope.ReleaseLease(lease);
//log issue
LogManager log = _log;
if (log != null)
{
log.Write(remoteEP as IPEndPoint, "DHCP Server received DECLINE message: " + lease.GetClientFullIdentifier() + " detected that IP address [" + lease.Address + "] is already in use.");
}
//update dns
UpdateDnsAuthZone(false, scope, lease);
//do nothing
return(null);
}
case DhcpMessageType.Release:
{
//cancel ip address lease
if (request.ServerIdentifier == null)
{
return(null); //client MUST include this option; do nothing
}
Scope scope = FindScope(request, remoteEP.Address, ipPacketInformation);
if (scope == null)
{
return(null); //no scope available; do nothing
}
if (!request.ServerIdentifier.Address.Equals(scope.InterfaceAddress))
{
return(null); //request not for this server; do nothing
}
Lease lease = scope.GetExistingLeaseOrOffer(request);
if (lease == null)
{
return(null); //no existing lease or offer available for client; do nothing
}
if (!lease.Address.Equals(request.ClientIpAddress))
{
return(null); //the client's notion of its IP address is not correct; do nothing
}
//release lease
scope.ReleaseLease(lease);
//log ip lease release
LogManager log = _log;
if (log != null)
{
log.Write(remoteEP as IPEndPoint, "DHCP Server released IP address [" + lease.Address.ToString() + "] that was leased to " + lease.GetClientFullIdentifier() + ".");
}
//update dns
UpdateDnsAuthZone(false, scope, lease);
//do nothing
return(null);
}
case DhcpMessageType.Inform:
{
//need only local config; already has ip address assigned externally/manually
Scope scope = FindScope(request, remoteEP.Address, ipPacketInformation);
if (scope == null)
{
return(null); //no scope available; do nothing
}
List <DhcpOption> options = scope.GetOptions(request, scope.InterfaceAddress);
if (options == null)
{
return(null);
}
//log inform
LogManager log = _log;
if (log != null)
{
log.Write(remoteEP as IPEndPoint, "DHCP Server received INFORM message from " + request.GetClientFullIdentifier() + ".");
}
return(new DhcpMessage(request, IPAddress.Any, scope.InterfaceAddress, options));
}
default:
return(null);
}
}
public Scope(BinaryReader bR)
{
if (Encoding.ASCII.GetString(bR.ReadBytes(2)) != "SC")
{
throw new InvalidDataException("DhcpServer scope file format is invalid.");
}
switch (bR.ReadByte())
{
case 1:
_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();
_domainName = bR.ReadShortString();
if (string.IsNullOrWhiteSpace(_domainName))
{
_domainName = null;
}
_dnsTtl = bR.ReadUInt32();
_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
{
_dnsServers = new IPAddress[count];
for (int i = 0; i < count; i++)
{
_dnsServers[i] = IPAddressExtension.Parse(bR);
}
}
}
}
{
int count = bR.ReadByte();
if (count > 0)
{
_winsServers = new IPAddress[count];
for (int i = 0; i < count; i++)
{
_winsServers[i] = IPAddressExtension.Parse(bR);
}
}
}
{
int count = bR.ReadByte();
if (count > 0)
{
_ntpServers = new IPAddress[count];
for (int i = 0; i < count; i++)
{
_ntpServers[i] = IPAddressExtension.Parse(bR);
}
}
}
{
int count = bR.ReadByte();
if (count > 0)
{
_staticRoutes = new ClasslessStaticRouteOption.Route[count];
for (int i = 0; i < count; i++)
{
_staticRoutes[i] = new ClasslessStaticRouteOption.Route(bR.BaseStream);
}
}
}
{
int count = bR.ReadByte();
if (count > 0)
{
_exclusions = new Exclusion[count];
for (int i = 0; i < count; i++)
{
_exclusions[i] = new Exclusion(IPAddressExtension.Parse(bR), IPAddressExtension.Parse(bR));
}
}
}
{
int count = bR.ReadInt32();
if (count > 0)
{
_reservedLeases = new Lease[count];
for (int i = 0; i < count; i++)
{
_reservedLeases[i] = new Lease(bR);
}
}
_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.");
}
}
internal void ReleaseLease(Lease lease)
{
_leases.TryRemove(lease.ClientIdentifier, out _);
_lastModified = DateTime.UtcNow;
}
internal Lease GetOffer(DhcpMessage request)
{
if (_leases.TryGetValue(request.ClientIdentifier, out Lease existingLease))
{
//lease already exists
return(existingLease);
}
if (_reservedLeases != null)
{
ClientIdentifierOption clientIdentifierKey = new ClientIdentifierOption(1, request.ClientHardwareAddress);
foreach (Lease reservedLease in _reservedLeases)
{
if (reservedLease.ClientIdentifier.Equals(clientIdentifierKey))
{
//reserved address exists
IPAddress reservedLeaseAddress = reservedLease.Address;
if (!IsAddressAvailable(ref reservedLeaseAddress))
{
break; //reserved lease address is already allocated so ignore reserved lease
}
Lease reservedOffer = new Lease(LeaseType.Reserved, request.ClientIdentifier, request.HostName?.HostName, request.ClientHardwareAddress, reservedLease.Address, null, GetLeaseTime());
return(_offers.AddOrUpdate(request.ClientIdentifier, reservedOffer, delegate(ClientIdentifierOption key, Lease existingValue)
{
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) && IsAddressAvailable(ref requestedAddress))
{
offerAddress = requestedAddress;
}
}
if (offerAddress == null)
{
lock (_lastAddressOfferedLock)
{
//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);
if (IsAddressAvailable(ref offerAddress))
{
break;
}
}
_lastAddressOffered = offerAddress;
}
}
Lease offerLease = new Lease(LeaseType.Dynamic, request.ClientIdentifier, request.HostName?.HostName, request.ClientHardwareAddress, offerAddress, null, GetLeaseTime());
return(_offers.AddOrUpdate(request.ClientIdentifier, offerLease, delegate(ClientIdentifierOption key, Lease existingValue)
{
return offerLease;
}));
}
private void UpdateDnsAuthZone(bool add, Scope scope, Lease lease)
{
UpdateDnsAuthZone(add, scope, lease.HostName, lease.Address);
}
private void UpdateDnsAuthZone(bool add, Scope scope, Lease lease)
{
if (_authoritativeZoneRoot == null)
{
return;
}
if (string.IsNullOrWhiteSpace(scope.DomainName))
{
return;
}
if (string.IsNullOrWhiteSpace(lease.HostName))
{
return;
}
if (!DnsClient.IsDomainNameValid(lease.HostName))
{
return;
}
if (add)
{
//update forward zone
{
if (!_authoritativeZoneRoot.ZoneExists(scope.DomainName))
{
//create forward zone
_authoritativeZoneRoot.SetRecords(scope.DomainName, DnsResourceRecordType.SOA, 14400, new DnsResourceRecordData[] { new DnsSOARecord(_authoritativeZoneRoot.ServerDomain, "hostmaster." + scope.DomainName, 1, 14400, 3600, 604800, 900) });
_authoritativeZoneRoot.SetRecords(scope.DomainName, DnsResourceRecordType.NS, 14400, new DnsResourceRecordData[] { new DnsNSRecord(_authoritativeZoneRoot.ServerDomain) });
_authoritativeZoneRoot.MakeZoneInternal(scope.DomainName);
}
_authoritativeZoneRoot.SetRecords(lease.HostName, DnsResourceRecordType.A, scope.DnsTtl, new DnsResourceRecordData[] { new DnsARecord(lease.Address) });
}
//update reverse zone
{
if (!_authoritativeZoneRoot.ZoneExists(scope.ReverseZone))
{
//create reverse zone
_authoritativeZoneRoot.SetRecords(scope.ReverseZone, DnsResourceRecordType.SOA, 14400, new DnsResourceRecordData[] { new DnsSOARecord(_authoritativeZoneRoot.ServerDomain, "hostmaster." + scope.ReverseZone, 1, 14400, 3600, 604800, 900) });
_authoritativeZoneRoot.SetRecords(scope.ReverseZone, DnsResourceRecordType.NS, 14400, new DnsResourceRecordData[] { new DnsNSRecord(_authoritativeZoneRoot.ServerDomain) });
_authoritativeZoneRoot.MakeZoneInternal(scope.ReverseZone);
}
_authoritativeZoneRoot.SetRecords(Scope.GetReverseZone(lease.Address, 32), DnsResourceRecordType.PTR, scope.DnsTtl, new DnsResourceRecordData[] { new DnsPTRRecord(lease.HostName) });
}
}
else
{
//remove from forward zone
_authoritativeZoneRoot.DeleteRecords(lease.HostName, DnsResourceRecordType.A);
//remove from reverse zone
_authoritativeZoneRoot.DeleteRecords(Scope.GetReverseZone(lease.Address, 32), DnsResourceRecordType.PTR);
}
}
