Dhcp Message and Options datagram parsers added

DnsServerCore/Dhcp/BroadcastAddressOption.cs

@@ -0,0 +1,68 @@
+/*
+Technitium DNS Server
+Copyright (C) 2019  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 System.IO;
+using System.Net;
+using TechnitiumLibrary.IO;
+
+namespace DnsServerCore.Dhcp
+{
+    class BroadcastAddressOption : DhcpOption
+    {
+        #region variables
+
+        readonly IPAddress _broadcastAddress;
+
+        #endregion
+
+        #region constructor
+
+        public BroadcastAddressOption(Stream s)
+            : base(DhcpOptionCode.BroadcastAddress)
+        {
+            int len = s.ReadByte();
+            if (len < 0)
+                throw new EndOfStreamException();
+
+            if (len != 4)
+                throw new InvalidDataException();
+
+            _broadcastAddress = new IPAddress(s.ReadBytes(4));
+        }
+
+        #endregion
+
+        #region protected
+
+        protected override void WriteOptionTo(Stream s)
+        {
+            s.WriteByte(4);
+            s.Write(_broadcastAddress.GetAddressBytes());
+        }
+
+        #endregion
+
+        #region properties
+
+        public IPAddress BroadcastAddress
+        { get { return _broadcastAddress; } }
+
+        #endregion
+    }
+}

DnsServerCore/Dhcp/ClientIdentifierOption.cs

@@ -0,0 +1,78 @@
+/*
+Technitium DNS Server
+Copyright (C) 2019  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 System;
+using System.IO;
+using TechnitiumLibrary.IO;
+
+namespace DnsServerCore.Dhcp
+{
+    class ClientIdentifierOption : DhcpOption
+    {
+        #region variables
+
+        readonly byte _type;
+        readonly byte[] _identifier;
+
+        #endregion
+
+        #region constructor
+
+        public ClientIdentifierOption(Stream s)
+            : base(DhcpOptionCode.ClientIdentifier)
+        {
+            int len = s.ReadByte();
+            if (len < 0)
+                throw new EndOfStreamException();
+
+            if (len < 2)
+                throw new InvalidDataException();
+
+            int type = s.ReadByte();
+            if (type < 0)
+                throw new EndOfStreamException();
+
+            _type = (byte)type;
+            _identifier = s.ReadBytes(len - 1);
+        }
+
+        #endregion
+
+        #region protected
+
+        protected override void WriteOptionTo(Stream s)
+        {
+            s.WriteByte(Convert.ToByte(_identifier.Length + 1));
+            s.WriteByte(_type);
+            s.Write(_identifier);
+        }
+
+        #endregion
+
+        #region properties
+
+        public byte Type
+        { get { return _type; } }
+
+        public byte[] Identifier
+        { get { return _identifier; } }
+
+        #endregion
+    }
+}

DnsServerCore/Dhcp/DhcpMessage.cs

@@ -0,0 +1,265 @@
+/*
+Technitium DNS Server
+Copyright (C) 2019  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 System;
+using System.Collections.Generic;
+using System.IO;
+using System.Net;
+using System.Net.Sockets;
+using TechnitiumLibrary.IO;
+
+namespace DnsServerCore.Dhcp
+{
+    enum DhcpMessageOpCode : byte
+    {
+        BootRequest = 1,
+        BootReply = 2
+    }
+
+    enum DhcpMessageHardwareAddressType : byte
+    {
+        Ethernet = 1
+    }
+
+    enum DhcpMessageFlags : ushort
+    {
+        Broadcast = 0x8000
+    }
+
+    class DhcpMessage
+    {
+        #region variables
+
+        const uint MAGIC_COOKIE = 0x63825363;
+
+        readonly DhcpMessageOpCode _op;
+        readonly DhcpMessageHardwareAddressType _htype;
+        readonly byte _hlen;
+        readonly byte _hops;
+
+        readonly uint _xid;
+
+        readonly ushort _secs;
+        readonly DhcpMessageFlags _flags;
+
+        readonly IPAddress _ciaddr;
+        readonly IPAddress _yiaddr;
+        readonly IPAddress _siaddr;
+        readonly IPAddress _giaddr;
+
+        readonly byte[] _chaddr;
+        readonly byte[] _sname;
+        readonly byte[] _file;
+
+        readonly List<DhcpOption> _options;
+
+        #endregion
+
+        #region constructor
+
+        public DhcpMessage(DhcpMessageOpCode op, uint xid, ushort secs, DhcpMessageFlags flags, IPAddress ciaddr, IPAddress yiaddr, IPAddress siaddr, IPAddress giaddr, byte[] chaddr, List<DhcpOption> options)
+        {
+            if (ciaddr.AddressFamily != AddressFamily.InterNetwork)
+                throw new ArgumentException("Address family not supported.", "ciaddr");
+
+            if (yiaddr.AddressFamily != AddressFamily.InterNetwork)
+                throw new ArgumentException("Address family not supported.", "yiaddr");
+
+            if (siaddr.AddressFamily != AddressFamily.InterNetwork)
+                throw new ArgumentException("Address family not supported.", "siaddr");
+
+            if (giaddr.AddressFamily != AddressFamily.InterNetwork)
+                throw new ArgumentException("Address family not supported.", "giaddr");
+
+            if (chaddr == null)
+            {
+                chaddr = new byte[16];
+            }
+            else
+            {
+                if (chaddr.Length > 16)
+                    throw new ArgumentException("Value cannot be greater that 16 bytes.", "chaddr");
+
+                if (chaddr.Length < 16)
+                {
+                    byte[] newchaddr = new byte[16];
+                    Buffer.BlockCopy(chaddr, 0, newchaddr, 0, chaddr.Length);
+                    chaddr = newchaddr;
+                }
+            }
+
+            _op = op;
+            _htype = DhcpMessageHardwareAddressType.Ethernet;
+            _hlen = 6;
+            _hops = 0;
+
+            _xid = xid;
+
+            _secs = secs;
+            _flags = flags;
+
+            _ciaddr = ciaddr;
+            _yiaddr = yiaddr;
+            _siaddr = siaddr;
+            _giaddr = giaddr;
+
+            _chaddr = chaddr;
+            _sname = new byte[64];
+            _file = new byte[128];
+
+            _options = options;
+        }
+
+        public DhcpMessage(Stream s)
+        {
+            byte[] buffer = new byte[4];
+
+            s.ReadBytes(buffer, 0, 4);
+            _op = (DhcpMessageOpCode)buffer[0];
+            _htype = (DhcpMessageHardwareAddressType)buffer[1];
+            _hlen = buffer[2];
+            _hops = buffer[3];
+
+            s.ReadBytes(buffer, 0, 4);
+            _xid = BitConverter.ToUInt32(buffer, 0);
+
+            s.ReadBytes(buffer, 0, 4);
+            _secs = BitConverter.ToUInt16(buffer, 0);
+            _flags = (DhcpMessageFlags)BitConverter.ToUInt16(buffer, 2);
+
+            s.ReadBytes(buffer, 0, 4);
+            _ciaddr = new IPAddress(buffer);
+
+            s.ReadBytes(buffer, 0, 4);
+            _yiaddr = new IPAddress(buffer);
+
+            s.ReadBytes(buffer, 0, 4);
+            _siaddr = new IPAddress(buffer);
+
+            s.ReadBytes(buffer, 0, 4);
+            _giaddr = new IPAddress(buffer);
+
+            _chaddr = s.ReadBytes(16);
+            _sname = s.ReadBytes(64);
+            _file = s.ReadBytes(128);
+
+            //read options
+            _options = new List<DhcpOption>();
+
+            s.ReadBytes(buffer, 0, 4);
+            Array.Reverse(buffer);
+            uint magicCookie = BitConverter.ToUInt32(buffer, 0);
+
+            if (magicCookie == MAGIC_COOKIE)
+            {
+                while (true)
+                {
+                    DhcpOption option = DhcpOption.Parse(s);
+                    if (option.Code == DhcpOptionCode.End)
+                        break;
+
+                    _options.Add(option);
+                }
+            }
+        }
+
+        #endregion
+
+        #region public
+
+        public void WriteTo(Stream s)
+        {
+            s.WriteByte((byte)_op);
+            s.WriteByte((byte)_htype);
+            s.WriteByte(_hlen);
+            s.WriteByte(_hops);
+
+            s.Write(BitConverter.GetBytes(_xid));
+
+            s.Write(BitConverter.GetBytes(_secs));
+            s.Write(BitConverter.GetBytes((ushort)_flags));
+
+            s.Write(_ciaddr.GetAddressBytes());
+            s.Write(_yiaddr.GetAddressBytes());
+            s.Write(_siaddr.GetAddressBytes());
+            s.Write(_giaddr.GetAddressBytes());
+
+            s.Write(_chaddr);
+            s.Write(_sname);
+            s.Write(_file);
+
+            //write options
+            s.Write(BitConverter.GetBytes(MAGIC_COOKIE));
+
+            foreach (DhcpOption option in _options)
+                option.WriteTo(s);
+        }
+
+        #endregion
+
+        #region properties
+
+        public DhcpMessageOpCode OpCode
+        { get { return _op; } }
+
+        public DhcpMessageHardwareAddressType HardwareAddressType
+        { get { return _htype; } }
+
+        public byte HardwareAddressLength
+        { get { return _hlen; } }
+
+        public byte Hops
+        { get { return _hops; } }
+
+        public uint TransactionId
+        { get { return _xid; } }
+
+        public ushort SecondsElapsed
+        { get { return _secs; } }
+
+        public DhcpMessageFlags Flags
+        { get { return _flags; } }
+
+        public IPAddress ClientIpAddress
+        { get { return _ciaddr; } }
+
+        public IPAddress YourClientIpAddress
+        { get { return _yiaddr; } }
+
+        public IPAddress NextServerIpAddress
+        { get { return _siaddr; } }
+
+        public IPAddress RelayAgentIpAddress
+        { get { return _giaddr; } }
+
+        public byte[] ClientHardwareAddress
+        { get { return _chaddr; } }
+
+        public byte[] ServerHostName
+        { get { return _sname; } }
+
+        public byte[] BootFileName
+        { get { return _file; } }
+
+        public IReadOnlyList<DhcpOption> Options
+        { get { return _options; } }
+
+        #endregion
+    }
+}

DnsServerCore/Dhcp/DhcpMessageTypeOption.cs

@@ -0,0 +1,82 @@
+/*
+Technitium DNS Server
+Copyright (C) 2019  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 System.IO;
+
+namespace DnsServerCore.Dhcp
+{
+    enum DhcpMessageType : byte
+    {
+        Discover = 1,
+        Offer = 2,
+        Request = 3,
+        Decline = 4,
+        Ack = 5,
+        Nak = 6,
+        Release = 7,
+        Inform = 8
+    }
+
+    class DhcpMessageTypeOption : DhcpOption
+    {
+        #region variables
+
+        readonly DhcpMessageType _messageType;
+
+        #endregion
+
+        #region constructor
+
+        public DhcpMessageTypeOption(Stream s)
+            : base(DhcpOptionCode.DhcpMessageType)
+        {
+            int len = s.ReadByte();
+            if (len < 0)
+                throw new EndOfStreamException();
+
+            if (len != 1)
+                throw new InvalidDataException();
+
+            int type = s.ReadByte();
+            if (type < 0)
+                throw new EndOfStreamException();
+
+            _messageType = (DhcpMessageType)type;
+        }
+
+        #endregion
+
+        #region protected
+
+        protected override void WriteOptionTo(Stream s)
+        {
+            s.WriteByte(1);
+            s.WriteByte((byte)_messageType);
+        }
+
+        #endregion
+
+        #region properties
+
+        public DhcpMessageType MessageType
+        { get { return _messageType; } }
+
+        #endregion
+    }
+}

DnsServerCore/Dhcp/DhcpOption.cs

@@ -0,0 +1,260 @@
+/*
+Technitium DNS Server
+Copyright (C) 2019  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 System;
+using System.IO;
+using TechnitiumLibrary.IO;
+
+namespace DnsServerCore.Dhcp
+{
+    enum DhcpOptionCode : byte
+    {
+        Pad = 0,
+        SubnetMask = 1,
+        TimeOffset = 2,
+        Router = 3,
+        TimeServer = 4,
+        NameServer = 5,
+        DomainNameServer = 6,
+        LogServer = 7,
+        CookieServer = 8,
+        LprServer = 9,
+        ImpressServer = 10,
+        ResourceLocationServer = 11,
+        HostName = 12,
+        BootFileSize = 13,
+        MeritDump = 14,
+        DomainName = 15,
+        SwapServer = 16,
+        RootPath = 17,
+        ExtensionPath = 18,
+        IpForwarding = 19,
+        NonLocalSourceRouting = 20,
+        PolicyFilter = 21,
+        MaximumDatagramReassemblySize = 22,
+        DefaultIpTtl = 23,
+        PathMtuAgingTimeout = 24,
+        PathMtuPlateauTable = 25,
+        InterfaceMtu = 26,
+        AllSubnetAreLocal = 27,
+        BroadcastAddress = 28,
+        PerformMaskDiscovery = 29,
+        MaskSupplier = 30,
+        PerformRouterDiscovery = 31,
+        RouterSolicitationAddress = 32,
+        StaticRoute = 33,
+        TrailerEncapsulation = 34,
+        ArpCacheTimeout = 35,
+        EthernetEncapsulation = 36,
+        TcpDefaultTtl = 37,
+        TcpKeepAliveInterval = 38,
+        TcpKeepAliveGarbage = 39,
+        NetworkInformationServiceDomain = 40,
+        NetworkInformationServers = 41,
+        NetworkTimeProtocolServers = 42,
+        VendorSpecificInformation = 43,
+        NetBiosOverTcpIpNameServer = 44,
+        NetBiosOverTcpIpDatagramDistributionServer = 45,
+        NetBiosOverTcpIpNodeType = 46,
+        NetBiosOverTcpIpScope = 47,
+        XWindowSystemFontServer = 48,
+        XWindowSystemDisplayManager = 49,
+        RequestedIpAddress = 50,
+        IpAddressLeaseTime = 51,
+        OptionOverload = 52,
+        DhcpMessageType = 53,
+        ServerIdentifier = 54,
+        ParameterRequestList = 55,
+        Message = 56,
+        MaximumDhcpMessageSize = 57,
+        RenewalTimeValue = 58,
+        RebindingTimeValue = 59,
+        VendorClassIdentifier = 60,
+        ClientIdentifier = 61,
+        NetworkInformationServicePlusDomain = 64,
+        NetworkInformationServicePlusServers = 65,
+        TftpServerName = 66,
+        BootfileName = 67,
+        MobileIpHomeAgent = 68,
+        SmtpServer = 69,
+        Pop3Server = 70,
+        NntpServer = 71,
+        DefaultWwwServer = 72,
+        DefaultFingerServer = 73,
+        DefaultIrc = 74,
+        StreetTalkServer = 75,
+        StreetTalkDirectoryAssistance = 76,
+        End = 255
+    }
+
+    class DhcpOption
+    {
+        #region variables
+
+        readonly DhcpOptionCode _code;
+        readonly byte[] _value;
+
+        #endregion
+
+        #region constructor
+
+        protected DhcpOption(DhcpOptionCode type)
+        {
+            _code = type;
+        }
+
+        private DhcpOption(DhcpOptionCode type, byte[] value)
+        {
+            _code = type;
+            _value = value;
+        }
+
+        #endregion
+
+        #region static
+
+        public static DhcpOption CreateEndOption()
+        {
+            return new DhcpOption(DhcpOptionCode.End);
+        }
+
+        public static DhcpOption Parse(Stream s)
+        {
+            int code = s.ReadByte();
+            if (code < 0)
+                throw new EndOfStreamException();
+
+            DhcpOptionCode optionCode = (DhcpOptionCode)code;
+
+            switch (optionCode)
+            {
+                case DhcpOptionCode.SubnetMask:
+                    return new SubnetMaskOption(s);
+
+                case DhcpOptionCode.Router:
+                    return new RouterOption(s);
+
+                case DhcpOptionCode.DomainNameServer:
+                    return new DomainNameServerOption(s);
+
+                case DhcpOptionCode.HostName:
+                    return new HostNameOption(s);
+
+                case DhcpOptionCode.DomainName:
+                    return new DomainNameOption(s);
+
+                case DhcpOptionCode.BroadcastAddress:
+                    return new BroadcastAddressOption(s);
+
+                case DhcpOptionCode.StaticRoute:
+                    return new StaticRouteOption(s);
+
+                case DhcpOptionCode.NetBiosOverTcpIpNameServer:
+                    return new NetBiosNameServerOption(s);
+
+                case DhcpOptionCode.RequestedIpAddress:
+                    return new RequestedIpAddressOption(s);
+
+                case DhcpOptionCode.IpAddressLeaseTime:
+                    return new IpAddressLeaseTimeOption(s);
+
+                case DhcpOptionCode.OptionOverload:
+                    return new OptionOverloadOption(s);
+
+                case DhcpOptionCode.DhcpMessageType:
+                    return new DhcpMessageTypeOption(s);
+
+                case DhcpOptionCode.ServerIdentifier:
+                    return new ServerIdentifierOption(s);
+
+                case DhcpOptionCode.ParameterRequestList:
+                    return new ParameterRequestListOption(s);
+
+                case DhcpOptionCode.Message:
+                    return new MessageOption(s);
+
+                case DhcpOptionCode.MaximumDhcpMessageSize:
+                    return new MaximumDhcpMessageSizeOption(s);
+
+                case DhcpOptionCode.RenewalTimeValue:
+                    return new RenewalTimeValueOption(s);
+
+                case DhcpOptionCode.RebindingTimeValue:
+                    return new RebindingTimeValueOption(s);
+
+                case DhcpOptionCode.ClientIdentifier:
+                    return new ClientIdentifierOption(s);
+
+                case DhcpOptionCode.Pad:
+                case DhcpOptionCode.End:
+                    return new DhcpOption(optionCode, null);
+
+                default:
+                    //unknown option
+                    int len = s.ReadByte();
+                    if (len < 0)
+                        throw new EndOfStreamException();
+
+                    return new DhcpOption(optionCode, s.ReadBytes(len));
+            }
+        }
+
+        #endregion
+
+        #region protected
+
+        protected virtual void WriteOptionTo(Stream s)
+        {
+            if (_value == null)
+                throw new NotImplementedException();
+
+            s.WriteByte(Convert.ToByte(_value.Length));
+            s.Write(_value);
+        }
+
+        #endregion
+
+        #region public
+
+        public void WriteTo(Stream s)
+        {
+            s.WriteByte((byte)_code);
+
+            switch (_code)
+            {
+                case DhcpOptionCode.Pad:
+                case DhcpOptionCode.End:
+                    break;
+
+                default:
+                    WriteOptionTo(s);
+                    break;
+            }
+        }
+
+        #endregion
+
+        #region properties
+
+        public DhcpOptionCode Code
+        { get { return _code; } }
+
+        #endregion
+    }
+}

DnsServerCore/Dhcp/DomainNameOption.cs

@@ -0,0 +1,69 @@
+/*
+Technitium DNS Server
+Copyright (C) 2019  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 System;
+using System.IO;
+using System.Text;
+using TechnitiumLibrary.IO;
+
+namespace DnsServerCore.Dhcp
+{
+    class DomainNameOption : DhcpOption
+    {
+        #region variables
+
+        readonly string _domainName;
+
+        #endregion
+
+        #region constructor
+
+        public DomainNameOption(Stream s)
+            : base(DhcpOptionCode.DomainName)
+        {
+            int len = s.ReadByte();
+            if (len < 0)
+                throw new EndOfStreamException();
+
+            if (len < 1)
+                throw new InvalidDataException();
+
+            _domainName = Encoding.ASCII.GetString(s.ReadBytes(len));
+        }
+
+        #endregion
+
+        #region protected
+
+        protected override void WriteOptionTo(Stream s)
+        {
+            s.WriteByte(Convert.ToByte(_domainName.Length));
+            s.Write(Encoding.ASCII.GetBytes(_domainName));
+        }
+
+        #endregion
+
+        #region properties
+
+        public string DomainName
+        { get { return _domainName; } }
+
+        #endregion
+    }
+}

DnsServerCore/Dhcp/DomainNameServerOption.cs

@@ -0,0 +1,74 @@
+/*
+Technitium DNS Server
+Copyright (C) 2019  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 System;
+using System.IO;
+using System.Net;
+using TechnitiumLibrary.IO;
+
+namespace DnsServerCore.Dhcp
+{
+    class DomainNameServerOption : DhcpOption
+    {
+        #region variables
+
+        readonly IPAddress[] _addresses;
+
+        #endregion
+
+        #region constructor
+
+        public DomainNameServerOption(Stream s)
+            : base(DhcpOptionCode.DomainNameServer)
+        {
+            int len = s.ReadByte();
+            if (len < 0)
+                throw new EndOfStreamException();
+
+            if ((len % 4 != 0) || (len < 4))
+                throw new InvalidDataException();
+
+            _addresses = new IPAddress[len / 4];
+
+            for (int i = 0; i < _addresses.Length; i++)
+                _addresses[i] = new IPAddress(s.ReadBytes(4));
+        }
+
+        #endregion
+
+        #region protected
+
+        protected override void WriteOptionTo(Stream s)
+        {
+            s.WriteByte(Convert.ToByte(_addresses.Length * 4));
+
+            foreach (IPAddress address in _addresses)
+                s.Write(address.GetAddressBytes());
+        }
+
+        #endregion
+
+        #region properties
+
+        public IPAddress[] Addresses
+        { get { return _addresses; } }
+
+        #endregion
+    }
+}

DnsServerCore/Dhcp/HostNameOption.cs

@@ -0,0 +1,69 @@
+/*
+Technitium DNS Server
+Copyright (C) 2019  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 System;
+using System.IO;
+using System.Text;
+using TechnitiumLibrary.IO;
+
+namespace DnsServerCore.Dhcp
+{
+    class HostNameOption : DhcpOption
+    {
+        #region variables
+
+        readonly string _hostName;
+
+        #endregion
+
+        #region constructor
+
+        public HostNameOption(Stream s)
+            : base(DhcpOptionCode.HostName)
+        {
+            int len = s.ReadByte();
+            if (len < 0)
+                throw new EndOfStreamException();
+
+            if (len < 1)
+                throw new InvalidDataException();
+
+            _hostName = Encoding.ASCII.GetString(s.ReadBytes(len));
+        }
+
+        #endregion
+
+        #region protected
+
+        protected override void WriteOptionTo(Stream s)
+        {
+            s.WriteByte(Convert.ToByte(_hostName.Length));
+            s.Write(Encoding.ASCII.GetBytes(_hostName));
+        }
+
+        #endregion
+
+        #region properties
+
+        public string HostName
+        { get { return _hostName; } }
+
+        #endregion
+    }
+}

DnsServerCore/Dhcp/IpAddressLeaseTimeOption.cs

@@ -0,0 +1,68 @@
+/*
+Technitium DNS Server
+Copyright (C) 2019  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 System;
+using System.IO;
+using TechnitiumLibrary.IO;
+
+namespace DnsServerCore.Dhcp
+{
+    class IpAddressLeaseTimeOption : DhcpOption
+    {
+        #region variables
+
+        readonly uint _leaseTime;
+
+        #endregion
+
+        #region constructor
+
+        public IpAddressLeaseTimeOption(Stream s)
+            : base(DhcpOptionCode.IpAddressLeaseTime)
+        {
+            int len = s.ReadByte();
+            if (len < 0)
+                throw new EndOfStreamException();
+
+            if (len != 4)
+                throw new InvalidDataException();
+
+            _leaseTime = BitConverter.ToUInt32(s.ReadBytes(4), 0);
+        }
+
+        #endregion
+
+        #region protected
+
+        protected override void WriteOptionTo(Stream s)
+        {
+            s.WriteByte(4);
+            s.Write(BitConverter.GetBytes(_leaseTime));
+        }
+
+        #endregion
+
+        #region properties
+
+        public uint LeaseTime
+        { get { return _leaseTime; } }
+
+        #endregion
+    }
+}

DnsServerCore/Dhcp/MaximumDhcpMessageSizeOption.cs

@@ -0,0 +1,68 @@
+/*
+Technitium DNS Server
+Copyright (C) 2019  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 System;
+using System.IO;
+using TechnitiumLibrary.IO;
+
+namespace DnsServerCore.Dhcp
+{
+    class MaximumDhcpMessageSizeOption : DhcpOption
+    {
+        #region variables
+
+        readonly ushort _length;
+
+        #endregion
+
+        #region constructor
+
+        public MaximumDhcpMessageSizeOption(Stream s)
+            : base(DhcpOptionCode.MaximumDhcpMessageSize)
+        {
+            int len = s.ReadByte();
+            if (len < 0)
+                throw new EndOfStreamException();
+
+            if (len != 2)
+                throw new InvalidDataException();
+
+            _length = BitConverter.ToUInt16(s.ReadBytes(2), 0);
+        }
+
+        #endregion
+
+        #region protected
+
+        protected override void WriteOptionTo(Stream s)
+        {
+            s.WriteByte(2);
+            s.Write(BitConverter.GetBytes(_length));
+        }
+
+        #endregion
+
+        #region properties
+
+        public uint Length
+        { get { return _length; } }
+
+        #endregion
+    }
+}

DnsServerCore/Dhcp/MessageOption.cs

@@ -0,0 +1,69 @@
+/*
+Technitium DNS Server
+Copyright (C) 2019  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 System;
+using System.IO;
+using System.Text;
+using TechnitiumLibrary.IO;
+
+namespace DnsServerCore.Dhcp
+{
+    class MessageOption : DhcpOption
+    {
+        #region variables
+
+        readonly string _text;
+
+        #endregion
+
+        #region constructor
+
+        public MessageOption(Stream s)
+            : base(DhcpOptionCode.Message)
+        {
+            int len = s.ReadByte();
+            if (len < 0)
+                throw new EndOfStreamException();
+
+            if (len < 1)
+                throw new InvalidDataException();
+
+            _text = Encoding.ASCII.GetString(s.ReadBytes(len));
+        }
+
+        #endregion
+
+        #region protected
+
+        protected override void WriteOptionTo(Stream s)
+        {
+            s.WriteByte(Convert.ToByte(_text.Length));
+            s.Write(Encoding.ASCII.GetBytes(_text));
+        }
+
+        #endregion
+
+        #region properties
+
+        public string Text
+        { get { return _text; } }
+
+        #endregion
+    }
+}

DnsServerCore/Dhcp/NetBiosNameServerOption.cs

@@ -0,0 +1,74 @@
+/*
+Technitium DNS Server
+Copyright (C) 2019  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 System;
+using System.IO;
+using System.Net;
+using TechnitiumLibrary.IO;
+
+namespace DnsServerCore.Dhcp
+{
+    class NetBiosNameServerOption : DhcpOption
+    {
+        #region variables
+
+        readonly IPAddress[] _addresses;
+
+        #endregion
+
+        #region constructor
+
+        public NetBiosNameServerOption(Stream s)
+            : base(DhcpOptionCode.NetBiosOverTcpIpNameServer)
+        {
+            int len = s.ReadByte();
+            if (len < 0)
+                throw new EndOfStreamException();
+
+            if ((len % 4 != 0) || (len < 4))
+                throw new InvalidDataException();
+
+            _addresses = new IPAddress[len / 4];
+
+            for (int i = 0; i < _addresses.Length; i++)
+                _addresses[i] = new IPAddress(s.ReadBytes(4));
+        }
+
+        #endregion
+
+        #region protected
+
+        protected override void WriteOptionTo(Stream s)
+        {
+            s.WriteByte(Convert.ToByte(_addresses.Length * 4));
+
+            foreach (IPAddress address in _addresses)
+                s.Write(address.GetAddressBytes());
+        }
+
+        #endregion
+
+        #region properties
+
+        public IPAddress[] Addresses
+        { get { return _addresses; } }
+
+        #endregion
+    }
+}

DnsServerCore/Dhcp/NetworkTimeProtocolServersOption.cs

@@ -0,0 +1,74 @@
+/*
+Technitium DNS Server
+Copyright (C) 2019  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 System;
+using System.IO;
+using System.Net;
+using TechnitiumLibrary.IO;
+
+namespace DnsServerCore.Dhcp
+{
+    class NetworkTimeProtocolServersOption : DhcpOption
+    {
+        #region variables
+
+        readonly IPAddress[] _addresses;
+
+        #endregion
+
+        #region constructor
+
+        public NetworkTimeProtocolServersOption(Stream s)
+            : base(DhcpOptionCode.NetworkTimeProtocolServers)
+        {
+            int len = s.ReadByte();
+            if (len < 0)
+                throw new EndOfStreamException();
+
+            if ((len % 4 != 0) || (len < 4))
+                throw new InvalidDataException();
+
+            _addresses = new IPAddress[len / 4];
+
+            for (int i = 0; i < _addresses.Length; i++)
+                _addresses[i] = new IPAddress(s.ReadBytes(4));
+        }
+
+        #endregion
+
+        #region protected
+
+        protected override void WriteOptionTo(Stream s)
+        {
+            s.WriteByte(Convert.ToByte(_addresses.Length * 4));
+
+            foreach (IPAddress address in _addresses)
+                s.Write(address.GetAddressBytes());
+        }
+
+        #endregion
+
+        #region properties
+
+        public IPAddress[] Addresses
+        { get { return _addresses; } }
+
+        #endregion
+    }
+}

DnsServerCore/Dhcp/OptionOverloadOption.cs

@@ -0,0 +1,77 @@
+/*
+Technitium DNS Server
+Copyright (C) 2019  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 System.IO;
+
+namespace DnsServerCore.Dhcp
+{
+    enum OptionOverloadValue : byte
+    {
+        FileFieldUsed = 1,
+        SnameFieldUsed = 2,
+        BothFieldsUsed = 3
+    }
+
+    class OptionOverloadOption : DhcpOption
+    {
+        #region variables
+
+        readonly OptionOverloadValue _value;
+
+        #endregion
+
+        #region constructor
+
+        public OptionOverloadOption(Stream s)
+            : base(DhcpOptionCode.OptionOverload)
+        {
+            int len = s.ReadByte();
+            if (len < 0)
+                throw new EndOfStreamException();
+
+            if (len != 1)
+                throw new InvalidDataException();
+
+            int value = s.ReadByte();
+            if (value < 0)
+                throw new EndOfStreamException();
+
+            _value = (OptionOverloadValue)value;
+        }
+
+        #endregion
+
+        #region protected
+
+        protected override void WriteOptionTo(Stream s)
+        {
+            s.WriteByte(4);
+            s.WriteByte((byte)_value);
+        }
+
+        #endregion
+
+        #region properties
+
+        public OptionOverloadValue Value
+        { get { return _value; } }
+
+        #endregion
+    }
+}

DnsServerCore/Dhcp/ParameterRequestListOption.cs

@@ -0,0 +1,79 @@
+/*
+Technitium DNS Server
+Copyright (C) 2019  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 System;
+using System.IO;
+
+namespace DnsServerCore.Dhcp
+{
+    class ParameterRequestListOption : DhcpOption
+    {
+        #region variables
+
+        readonly DhcpOptionCode[] _optionCodes;
+
+        #endregion
+
+        #region constructor
+
+        public ParameterRequestListOption(Stream s)
+            : base(DhcpOptionCode.ParameterRequestList)
+        {
+            int len = s.ReadByte();
+            if (len < 0)
+                throw new EndOfStreamException();
+
+            if (len < 1)
+                throw new InvalidDataException();
+
+            _optionCodes = new DhcpOptionCode[len];
+            int optionCode;
+
+            for (int i = 0; i < _optionCodes.Length; i++)
+            {
+                optionCode = s.ReadByte();
+                if (optionCode < 0)
+                    throw new EndOfStreamException();
+
+                _optionCodes[i] = (DhcpOptionCode)optionCode;
+            }
+        }
+
+        #endregion
+
+        #region protected
+
+        protected override void WriteOptionTo(Stream s)
+        {
+            s.WriteByte(Convert.ToByte(_optionCodes.Length));
+
+            foreach (DhcpOptionCode optionCode in _optionCodes)
+                s.WriteByte((byte)optionCode);
+        }
+
+        #endregion
+
+        #region properties
+
+        public DhcpOptionCode[] OptionCodes
+        { get { return _optionCodes; } }
+
+        #endregion
+    }
+}

DnsServerCore/Dhcp/RebindingTimeValueOption.cs

@@ -0,0 +1,68 @@
+/*
+Technitium DNS Server
+Copyright (C) 2019  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 System;
+using System.IO;
+using TechnitiumLibrary.IO;
+
+namespace DnsServerCore.Dhcp
+{
+    class RebindingTimeValueOption : DhcpOption
+    {
+        #region variables
+
+        readonly uint _t2Interval;
+
+        #endregion
+
+        #region constructor
+
+        public RebindingTimeValueOption(Stream s)
+            : base(DhcpOptionCode.RebindingTimeValue)
+        {
+            int len = s.ReadByte();
+            if (len < 0)
+                throw new EndOfStreamException();
+
+            if (len != 4)
+                throw new InvalidDataException();
+
+            _t2Interval = BitConverter.ToUInt32(s.ReadBytes(4), 0);
+        }
+
+        #endregion
+
+        #region protected
+
+        protected override void WriteOptionTo(Stream s)
+        {
+            s.WriteByte(4);
+            s.Write(BitConverter.GetBytes(_t2Interval));
+        }
+
+        #endregion
+
+        #region properties
+
+        public uint T2Interval
+        { get { return _t2Interval; } }
+
+        #endregion
+    }
+}

DnsServerCore/Dhcp/RenewalTimeValueOption.cs

@@ -0,0 +1,68 @@
+/*
+Technitium DNS Server
+Copyright (C) 2019  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 System;
+using System.IO;
+using TechnitiumLibrary.IO;
+
+namespace DnsServerCore.Dhcp
+{
+    class RenewalTimeValueOption : DhcpOption
+    {
+        #region variables
+
+        readonly uint _t1Interval;
+
+        #endregion
+
+        #region constructor
+
+        public RenewalTimeValueOption(Stream s)
+            : base(DhcpOptionCode.RenewalTimeValue)
+        {
+            int len = s.ReadByte();
+            if (len < 0)
+                throw new EndOfStreamException();
+
+            if (len != 4)
+                throw new InvalidDataException();
+
+            _t1Interval = BitConverter.ToUInt32(s.ReadBytes(4), 0);
+        }
+
+        #endregion
+
+        #region protected
+
+        protected override void WriteOptionTo(Stream s)
+        {
+            s.WriteByte(4);
+            s.Write(BitConverter.GetBytes(_t1Interval));
+        }
+
+        #endregion
+
+        #region properties
+
+        public uint T1Interval
+        { get { return _t1Interval; } }
+
+        #endregion
+    }
+}

DnsServerCore/Dhcp/RequestedIpAddressOption.cs

@@ -0,0 +1,68 @@
+/*
+Technitium DNS Server
+Copyright (C) 2019  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 System.IO;
+using System.Net;
+using TechnitiumLibrary.IO;
+
+namespace DnsServerCore.Dhcp
+{
+    class RequestedIpAddressOption : DhcpOption
+    {
+        #region variables
+
+        readonly IPAddress _address;
+
+        #endregion
+
+        #region constructor
+
+        public RequestedIpAddressOption(Stream s)
+            : base(DhcpOptionCode.RequestedIpAddress)
+        {
+            int len = s.ReadByte();
+            if (len < 0)
+                throw new EndOfStreamException();
+
+            if (len != 4)
+                throw new InvalidDataException();
+
+            _address = new IPAddress(s.ReadBytes(4));
+        }
+
+        #endregion
+
+        #region protected
+
+        protected override void WriteOptionTo(Stream s)
+        {
+            s.WriteByte(4);
+            s.Write(_address.GetAddressBytes());
+        }
+
+        #endregion
+
+        #region properties
+
+        public IPAddress Address
+        { get { return _address; } }
+
+        #endregion
+    }
+}

DnsServerCore/Dhcp/RouterOption.cs

@@ -0,0 +1,74 @@
+/*
+Technitium DNS Server
+Copyright (C) 2019  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 System;
+using System.IO;
+using System.Net;
+using TechnitiumLibrary.IO;
+
+namespace DnsServerCore.Dhcp
+{
+    class RouterOption : DhcpOption
+    {
+        #region variables
+
+        readonly IPAddress[] _addresses;
+
+        #endregion
+
+        #region constructor
+
+        public RouterOption(Stream s)
+            : base(DhcpOptionCode.Router)
+        {
+            int len = s.ReadByte();
+            if (len < 0)
+                throw new EndOfStreamException();
+
+            if ((len % 4 != 0) || (len < 4))
+                throw new InvalidDataException();
+
+            _addresses = new IPAddress[len / 4];
+
+            for (int i = 0; i < _addresses.Length; i++)
+                _addresses[i] = new IPAddress(s.ReadBytes(4));
+        }
+
+        #endregion
+
+        #region protected
+
+        protected override void WriteOptionTo(Stream s)
+        {
+            s.WriteByte(Convert.ToByte(_addresses.Length * 4));
+
+            foreach (IPAddress address in _addresses)
+                s.Write(address.GetAddressBytes());
+        }
+
+        #endregion
+
+        #region properties
+
+        public IPAddress[] Addresses
+        { get { return _addresses; } }
+
+        #endregion
+    }
+}

DnsServerCore/Dhcp/ServerIdentifierOption.cs

@@ -0,0 +1,68 @@
+/*
+Technitium DNS Server
+Copyright (C) 2019  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 System.IO;
+using System.Net;
+using TechnitiumLibrary.IO;
+
+namespace DnsServerCore.Dhcp
+{
+    class ServerIdentifierOption : DhcpOption
+    {
+        #region variables
+
+        readonly IPAddress _address;
+
+        #endregion
+
+        #region constructor
+
+        public ServerIdentifierOption(Stream s)
+            : base(DhcpOptionCode.ServerIdentifier)
+        {
+            int len = s.ReadByte();
+            if (len < 0)
+                throw new EndOfStreamException();
+
+            if (len != 4)
+                throw new InvalidDataException();
+
+            _address = new IPAddress(s.ReadBytes(4));
+        }
+
+        #endregion
+
+        #region protected
+
+        protected override void WriteOptionTo(Stream s)
+        {
+            s.WriteByte(4);
+            s.Write(_address.GetAddressBytes());
+        }
+
+        #endregion
+
+        #region properties
+
+        public IPAddress Address
+        { get { return _address; } }
+
+        #endregion
+    }
+}

DnsServerCore/Dhcp/StaticRouteOption.cs

@@ -0,0 +1,77 @@
+/*
+Technitium DNS Server
+Copyright (C) 2019  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 System;
+using System.IO;
+using System.Net;
+using TechnitiumLibrary.IO;
+
+namespace DnsServerCore.Dhcp
+{
+    class StaticRouteOption : DhcpOption
+    {
+        #region variables
+
+        readonly Tuple<IPAddress, IPAddress>[] _routes;
+
+        #endregion
+
+        #region constructor
+
+        public StaticRouteOption(Stream s)
+            : base(DhcpOptionCode.StaticRoute)
+        {
+            int len = s.ReadByte();
+            if (len < 0)
+                throw new EndOfStreamException();
+
+            if ((len % 8 != 0) || (len < 8))
+                throw new InvalidDataException();
+
+            _routes = new Tuple<IPAddress, IPAddress>[len / 8];
+
+            for (int i = 0; i < _routes.Length; i++)
+                _routes[i] = new Tuple<IPAddress, IPAddress>(new IPAddress(s.ReadBytes(4)), new IPAddress(s.ReadBytes(4)));
+        }
+
+        #endregion
+
+        #region protected
+
+        protected override void WriteOptionTo(Stream s)
+        {
+            s.WriteByte(Convert.ToByte(_routes.Length * 4));
+
+            foreach (Tuple<IPAddress, IPAddress> route in _routes)
+            {
+                s.Write(route.Item1.GetAddressBytes());
+                s.Write(route.Item2.GetAddressBytes());
+            }
+        }
+
+        #endregion
+
+        #region properties
+
+        public Tuple<IPAddress, IPAddress>[] Routes
+        { get { return _routes; } }
+
+        #endregion
+    }
+}

DnsServerCore/Dhcp/SubnetMaskOption.cs

@@ -0,0 +1,68 @@
+/*
+Technitium DNS Server
+Copyright (C) 2019  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 System.IO;
+using System.Net;
+using TechnitiumLibrary.IO;
+
+namespace DnsServerCore.Dhcp
+{
+    class SubnetMaskOption : DhcpOption
+    {
+        #region variables
+
+        readonly IPAddress _subnetMask;
+
+        #endregion
+
+        #region constructor
+
+        public SubnetMaskOption(Stream s)
+            : base(DhcpOptionCode.SubnetMask)
+        {
+            int len = s.ReadByte();
+            if (len < 0)
+                throw new EndOfStreamException();
+
+            if (len != 4)
+                throw new InvalidDataException();
+
+            _subnetMask = new IPAddress(s.ReadBytes(4));
+        }
+
+        #endregion
+
+        #region protected
+
+        protected override void WriteOptionTo(Stream s)
+        {
+            s.WriteByte(4);
+            s.Write(_subnetMask.GetAddressBytes());
+        }
+
+        #endregion
+
+        #region properties
+
+        public IPAddress SubnetMask
+        { get { return _subnetMask; } }
+
+        #endregion
+    }
+}