private void ProcessUdpRequestAsync(object parameter)
{
object[] parameters = parameter as object[];
Socket udpListener = parameters[0] as Socket;
EndPoint remoteEP = parameters[1] as EndPoint;
IPPacketInformation ipPacketInformation = (IPPacketInformation)parameters[2];
DhcpMessage request = parameters[3] as DhcpMessage;
try
{
DhcpMessage response = ProcessDhcpMessage(request, remoteEP as IPEndPoint, ipPacketInformation);
//send response
if (response != null)
{
byte[] sendBuffer = new byte[1024];
MemoryStream sendBufferStream = new MemoryStream(sendBuffer);
response.WriteTo(sendBufferStream);
//send dns datagram
if (!request.RelayAgentIpAddress.Equals(IPAddress.Any))
{
//received request via relay agent so send unicast response to relay agent on port 67
udpListener.SendTo(sendBuffer, 0, (int)sendBufferStream.Position, SocketFlags.None, new IPEndPoint(request.RelayAgentIpAddress, 67));
}
else if (!request.ClientIpAddress.Equals(IPAddress.Any))
{
//client is already configured and renewing lease so send unicast response on port 68
udpListener.SendTo(sendBuffer, 0, (int)sendBufferStream.Position, SocketFlags.None, new IPEndPoint(request.ClientIpAddress, 68));
}
else
{
//send response as broadcast on port 68 on appropriate interface bound socket
if (!_udpListeners.TryGetValue(response.NextServerIpAddress, out Socket udpSocket))
{
udpSocket = udpListener; //no appropriate socket found so use default socket
}
udpSocket.SendTo(sendBuffer, 0, (int)sendBufferStream.Position, SocketFlags.DontRoute, new IPEndPoint(IPAddress.Broadcast, 68)); //no routing for broadcast
}
}
}
catch (ObjectDisposedException)
{
//socket disposed
}
catch (Exception ex)
{
if ((_state == ServiceState.Stopping) || (_state == ServiceState.Stopped))
{
return; //server stopping
}
LogManager log = _log;
if (log != null)
{
log.Write(remoteEP as IPEndPoint, ex);
}
}
}
private async Task ProcessDhcpRequestAsync(DhcpMessage request, IPEndPoint remoteEP, IPPacketInformation ipPacketInformation, Socket udpListener)
{
try
{
DhcpMessage response = await ProcessDhcpMessageAsync(request, remoteEP, ipPacketInformation);
//send response
if (response != null)
{
byte[] sendBuffer = new byte[1024];
MemoryStream sendBufferStream = new MemoryStream(sendBuffer);
response.WriteTo(sendBufferStream);
//send dns datagram
if (!request.RelayAgentIpAddress.Equals(IPAddress.Any))
{
//received request via relay agent so send unicast response to relay agent on port 67
await udpListener.SendToAsync(sendBuffer, 0, (int)sendBufferStream.Position, new IPEndPoint(request.RelayAgentIpAddress, 67));
}
else if (!request.ClientIpAddress.Equals(IPAddress.Any))
{
//client is already configured and renewing lease so send unicast response on port 68
await udpListener.SendToAsync(sendBuffer, 0, (int)sendBufferStream.Position, new IPEndPoint(request.ClientIpAddress, 68));
}
else
{
Socket udpSocket;
//send response as broadcast on port 68 on appropriate interface bound socket
if (_udpListeners.TryGetValue(response.NextServerIpAddress, out UdpListener listener))
{
udpSocket = listener.Socket; //found scope specific socket
}
else
{
udpSocket = udpListener; //no appropriate socket found so use default socket
}
await udpSocket.SendToAsync(sendBuffer, 0, (int)sendBufferStream.Position, new IPEndPoint(IPAddress.Broadcast, 68), SocketFlags.DontRoute); //no routing for broadcast
}
}
}
catch (ObjectDisposedException)
{
//socket disposed
}
catch (Exception ex)
{
if ((_state == ServiceState.Stopping) || (_state == ServiceState.Stopped))
{
return; //server stopping
}
LogManager log = _log;
if (log != null)
{
log.Write(remoteEP, ex);
}
}
}
private Scope FindScope(DhcpMessage request, IPAddress remoteAddress, IPPacketInformation ipPacketInformation)
{
bool broadcast;
if (request.RelayAgentIpAddress.Equals(IPAddress.Any))
{
//no relay agent
if (request.ClientIpAddress.Equals(IPAddress.Any))
{
if (!ipPacketInformation.Address.Equals(IPAddress.Broadcast))
{
return(null); //message destination address must be broadcast address
}
broadcast = true; //broadcast request
}
else
{
if (!remoteAddress.Equals(request.ClientIpAddress))
{
return(null); //client ip must match udp src addr
}
broadcast = false; //unicast request
}
}
else
{
//relay agent unicast
if (!remoteAddress.Equals(request.RelayAgentIpAddress))
{
return(null); //relay ip must match udp src addr
}
broadcast = false; //unicast request
}
if (broadcast)
{
foreach (KeyValuePair <string, Scope> scope in _scopes)
{
if (scope.Value.Enabled && (scope.Value.InterfaceIndex == ipPacketInformation.Interface))
{
return(scope.Value);
}
}
}
else
{
foreach (KeyValuePair <string, Scope> scope in _scopes)
{
if (scope.Value.Enabled && (scope.Value.IsAddressInRange(remoteAddress)))
{
return(scope.Value);
}
}
}
return(null);
}
internal Lease GetExistingLeaseOrOffer(DhcpMessage request)
{
if (_leases.TryGetValue(request.ClientIdentifier, out Lease existingLease))
{
return(existingLease);
}
if (_offers.TryGetValue(request.ClientIdentifier, out Lease existingOffer))
{
return(existingOffer);
}
return(null);
}
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);
}
}
internal List <DhcpOption> GetOptions(DhcpMessage request, IPAddress serverIdentifierAddress)
{
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));
}
}
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));
}
}
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;
}
}
}
options.Add(DhcpOption.CreateEndOption());
return(options);
}
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 ClientFullyQualifiedDomainNameOption GetClientFullyQualifiedDomainNameOption(DhcpMessage request)
{
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(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 Scope FindScope(DhcpMessage request, IPAddress remoteAddress, IPPacketInformation ipPacketInformation)
{
if (request.RelayAgentIpAddress.Equals(IPAddress.Any))
{
//no relay agent
if (request.ClientIpAddress.Equals(IPAddress.Any))
{
if (!ipPacketInformation.Address.Equals(IPAddress.Broadcast))
{
return(null); //message destination address must be broadcast address
}
//broadcast request
Scope foundScope = null;
foreach (Scope scope in _scopes.Values)
{
if (scope.Enabled && (scope.InterfaceIndex == ipPacketInformation.Interface))
{
if (scope.GetReservedLease(request) != null)
{
return(scope); //found reserved lease on this scope
}
if ((foundScope == null) && !scope.AllowOnlyReservedLeases)
{
foundScope = scope;
}
}
}
return(foundScope);
}
else
{
if (!remoteAddress.Equals(request.ClientIpAddress))
{
return(null); //client ip must match udp src addr
}
//unicast request
foreach (Scope scope in _scopes.Values)
{
if (scope.Enabled && scope.IsAddressInRange(remoteAddress))
{
return(scope);
}
}
return(null);
}
}
else
{
//relay agent unicast
Scope foundScope = null;
foreach (Scope scope in _scopes.Values)
{
if (scope.Enabled && scope.InterfaceAddress.Equals(IPAddress.Any))
{
if (scope.GetReservedLease(request) != null)
{
return(scope); //found reserved lease on this scope
}
if (!request.ClientIpAddress.Equals(IPAddress.Any) && scope.IsAddressInRange(request.ClientIpAddress))
{
foundScope = scope; //client IP address is in scope range
}
else if ((foundScope == null) && scope.IsAddressInRange(request.RelayAgentIpAddress))
{
foundScope = scope; //relay agent IP address is in scope range
}
}
}
return(foundScope);
}
}
private void ReadUdpRequestAsync(object parameter)
{
Socket udpListener = parameter as Socket;
EndPoint remoteEP = new IPEndPoint(IPAddress.Any, 0);
byte[] recvBuffer = new byte[576];
int bytesRecv;
try
{
bool processOnlyUnicastMessages = !(udpListener.LocalEndPoint as IPEndPoint).Address.Equals(IPAddress.Any); //only 0.0.0.0 ip should process broadcast to avoid duplicate offers on Windows
while (true)
{
SocketFlags flags = SocketFlags.None;
IPPacketInformation ipPacketInformation;
try
{
bytesRecv = udpListener.ReceiveMessageFrom(recvBuffer, 0, recvBuffer.Length, ref flags, ref remoteEP, out ipPacketInformation);
}
catch (SocketException ex)
{
switch (ex.SocketErrorCode)
{
case SocketError.ConnectionReset:
case SocketError.HostUnreachable:
case SocketError.MessageSize:
case SocketError.NetworkReset:
bytesRecv = 0;
break;
default:
throw;
}
}
if (bytesRecv > 0)
{
if (processOnlyUnicastMessages && ipPacketInformation.Address.Equals(IPAddress.Broadcast))
{
continue;
}
try
{
DhcpMessage request = new DhcpMessage(new MemoryStream(recvBuffer, 0, bytesRecv, false));
_ = ProcessDhcpRequestAsync(request, remoteEP as IPEndPoint, ipPacketInformation, udpListener);
}
catch (Exception ex)
{
LogManager log = _log;
if (log != null)
{
log.Write(remoteEP as IPEndPoint, ex);
}
}
}
}
}
catch (ObjectDisposedException)
{
//socket disposed
}
catch (SocketException ex)
{
switch (ex.SocketErrorCode)
{
case SocketError.Interrupted:
break; //server stopping
default:
LogManager log = _log;
if (log != null)
{
log.Write(remoteEP as IPEndPoint, ex);
}
throw;
}
}
catch (Exception ex)
{
if ((_state == ServiceState.Stopping) || (_state == ServiceState.Stopped))
{
return; //server stopping
}
LogManager log = _log;
if (log != null)
{
log.Write(remoteEP as IPEndPoint, ex);
}
throw;
}
}
public DhcpMessage(DhcpMessage request, IPAddress yiaddr, IPAddress siaddr, IReadOnlyCollection <DhcpOption> options)
: this(DhcpMessageOpCode.BootReply, request.TransactionId, request.SecondsElapsed, request.Flags, request.ClientIpAddress, yiaddr, siaddr, request.RelayAgentIpAddress, request.ClientHardwareAddress, options)
{
}
public static DhcpMessage CreateReply(DhcpMessage request, IPAddress yiaddr, IPAddress siaddr, string sname, string file, IReadOnlyCollection <DhcpOption> options)
{
return(new DhcpMessage(DhcpMessageOpCode.BootReply, request.HardwareAddressType, request.TransactionId, request.SecondsElapsed, request.Flags, request.ClientIpAddress, yiaddr, siaddr, request.RelayAgentIpAddress, request.ClientHardwareAddress, sname, file, options));
}
internal Lease GetReservedLease(DhcpMessage request)
{
return(GetReservedLease(new ClientIdentifierOption((byte)request.HardwareAddressType, request.ClientHardwareAddress)));
}