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DhcpMessage: added support for sname and file fields.

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This commit is contained in:
Shreyas Zare
2020-10-24 16:53:54 +05:30
parent 7de99aca59
commit 795bfdb015
1 changed files with 71 additions and 17 deletions
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88
DnsServerCore/Dhcp/DhcpMessage.cs
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@@ -23,6 +23,7 @@ using System.Collections.Generic;
using System.IO;
using System.Net;
using System.Net.Sockets;
using System.Text;
using TechnitiumLibrary.IO;
namespace DnsServerCore.Dhcp
@@ -72,6 +73,8 @@ namespace DnsServerCore.Dhcp
readonly IReadOnlyCollection<DhcpOption> _options;
readonly byte[] _clientHardwareAddress;
readonly string _serverHostName;
readonly string _bootFileName;
OptionOverloadOption _optionOverload;
@@ -88,7 +91,7 @@ namespace DnsServerCore.Dhcp
#region constructor
public DhcpMessage(DhcpMessageOpCode op, DhcpMessageHardwareAddressType hardwareAddressType, byte[] xid, byte[] secs, DhcpMessageFlags flags, IPAddress ciaddr, IPAddress yiaddr, IPAddress siaddr, IPAddress giaddr, byte[] clientHardwareAddress, IReadOnlyCollection<DhcpOption> options)
public DhcpMessage(DhcpMessageOpCode op, DhcpMessageHardwareAddressType hardwareAddressType, byte[] xid, byte[] secs, DhcpMessageFlags flags, IPAddress ciaddr, IPAddress yiaddr, IPAddress siaddr, IPAddress giaddr, byte[] clientHardwareAddress, string sname, string file, IReadOnlyCollection<DhcpOption> options)
{
if (ciaddr.AddressFamily != AddressFamily.InterNetwork)
throw new ArgumentException("Address family not supported.", nameof(ciaddr));
@@ -106,7 +109,7 @@ namespace DnsServerCore.Dhcp
throw new ArgumentNullException(nameof(clientHardwareAddress));
if (clientHardwareAddress.Length > 16)
throw new ArgumentException("Client hardware address cannot exceed 16 bytes.", "chaddr");
throw new ArgumentException("Client hardware address cannot exceed 16 bytes.", nameof(clientHardwareAddress));
if (xid.Length != 4)
throw new ArgumentException("Transaction ID must be 4 bytes.", nameof(xid));
@@ -134,7 +137,28 @@ namespace DnsServerCore.Dhcp
Buffer.BlockCopy(_clientHardwareAddress, 0, _chaddr, 0, _clientHardwareAddress.Length);
_sname = new byte[64];
if (sname != null)
{
_serverHostName = sname;
byte[] buffer = Encoding.ASCII.GetBytes(sname);
if (buffer.Length >= 64)
throw new ArgumentException("Server host name cannot exceed 63 bytes.", nameof(sname));
Buffer.BlockCopy(buffer, 0, _sname, 0, buffer.Length);
}
_file = new byte[128];
if (file != null)
{
_bootFileName = file;
byte[] buffer = Encoding.ASCII.GetBytes(file);
if (buffer.Length >= 128)
throw new ArgumentException("Boot file name cannot exceed 127 bytes.", nameof(file));
Buffer.BlockCopy(buffer, 0, _file, 0, buffer.Length);
}
_options = options;
@@ -148,10 +172,6 @@ namespace DnsServerCore.Dhcp
}
}
public DhcpMessage(DhcpMessage request, IPAddress yiaddr, IPAddress siaddr, IReadOnlyCollection<DhcpOption> options)
: this(DhcpMessageOpCode.BootReply, request.HardwareAddressType, request.TransactionId, request.SecondsElapsed, request.Flags, request.ClientIpAddress, yiaddr, siaddr, request.RelayAgentIpAddress, request.ClientHardwareAddress, options)
{ }
public DhcpMessage(Stream s)
{
byte[] buffer = new byte[4];
@@ -200,21 +220,46 @@ namespace DnsServerCore.Dhcp
{
ParseOptions(s, options);
if (_optionOverload != null)
if ((_optionOverload != null) && _optionOverload.Value.HasFlag(OptionOverloadValue.FileFieldUsed))
{
if (_optionOverload.Value.HasFlag(OptionOverloadValue.FileFieldUsed))
using (MemoryStream mS = new MemoryStream(_file))
{
using (MemoryStream mS = new MemoryStream(_file))
ParseOptions(mS, options);
}
}
else
{
for (int i = 0; i < _file.Length; i++)
{
if (_file[i] == 0)
{
ParseOptions(mS, options);
if (i == 0)
break;
_bootFileName = Encoding.ASCII.GetString(_file, 0, i);
break;
}
}
}
if (_optionOverload.Value.HasFlag(OptionOverloadValue.SnameFieldUsed))
if ((_optionOverload != null) && _optionOverload.Value.HasFlag(OptionOverloadValue.SnameFieldUsed))
{
using (MemoryStream mS = new MemoryStream(_sname))
{
using (MemoryStream mS = new MemoryStream(_sname))
ParseOptions(mS, options);
}
}
else
{
for (int i = 0; i < _sname.Length; i++)
{
if (_sname[i] == 0)
{
ParseOptions(mS, options);
if (i == 0)
break;
_serverHostName = Encoding.ASCII.GetString(_sname, 0, i);
break;
}
}
}
@@ -233,6 +278,15 @@ namespace DnsServerCore.Dhcp
#endregion
#region static
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);
}
#endregion
#region private
private void ParseOptions(Stream s, List<DhcpOption> options)
@@ -393,11 +447,11 @@ namespace DnsServerCore.Dhcp
public byte[] ClientHardwareAddress
{ get { return _clientHardwareAddress; } }
public byte[] ServerHostName
{ get { return _sname; } }
public string ServerHostName
{ get { return _serverHostName; } }
public byte[] BootFileName
{ get { return _file; } }
public string BootFileName
{ get { return _bootFileName; } }
public IReadOnlyCollection<DhcpOption> Options
{ get { return _options; } }