singrdk/base/Services/NetStack/Protocol/DhcpFmt.cs

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2008-03-05 09:52:00 -05:00
///////////////////////////////////////////////////////////////////////////////
//
// Microsoft Research Singularity
//
// Copyright (c) Microsoft Corporation. All rights reserved.
//
// File: DhcpFmt.cs
//
// Note: The key DHCP RFC is 2131.
//
using NetStack.Common;
using System;
using System.Collections;
using System.Net.IP;
using Drivers.Net;
namespace NetStack.Protocols
{
public class InvalidDhcpFormatException : SystemException
{
public InvalidDhcpFormatException(String message)
: base(message)
{
}
public InvalidDhcpFormatException(String message,
Exception innerException)
: base(message, innerException)
{
}
public InvalidDhcpFormatException(String format, params object [] args)
: base (String.Format(format, args))
{
}
}
sealed public class DhcpFormat
{
#region FormatFields
internal byte op; // Message Type
internal byte htype; // Hardware Type
internal byte hlen; // Hardware Length
internal byte hops; // Relay hops
internal uint xid; // Transaction ID (host order)
internal ushort secs; // Seconds since transaction start (host order)
internal ushort flags; // Flags (host order)
internal uint ciaddr; // Client IP if known (host order)
internal uint yiaddr; // Your IP address (host order)
internal uint siaddr; // Next Server address (host order)
internal uint giaddr; // Relay agent IP address (host order)
internal byte [] chaddr; // Client h/w address (16-bytes)
internal byte []! sname; // Optional server name (64-bytes null term)
internal byte [] file; // Boot file name (128-bytes null terminated)
internal uint cookie; // Mandatory DHCP option
internal byte [] options; // Variable size
#endregion // FormatFields
internal int optionsUsedLength;
// Constants
public const int MinLength = 240; // Min DHCP packet
public const int HardwareAddressLength = 16; // chaddr fixed length
public const int ServerNameLength = 64; // sname fixed length
public const int BootFileLength = 128; // file length
public const int MaxOptionsLength = 512; // Really H/W dependent
private const byte EndMarker = 255;
private const int EndMarkerLength = 1;
internal const uint DhcpCookie = 0x63825363; // DHCP Cookie
public const int ClientPort = 68;
public const int ServerPort = 67;
public enum BootType : byte
{
NotSpecified = 0,
Request = 1, // Client to Server Message
Reply = 2 // Server to Client Message
}
public enum MessageType : byte
{
Discover = 1,
Offer = 2,
Request = 3,
Decline = 4,
Ack = 5,
Nak = 6,
Release = 7,
Inform = 8
}
// http://www.iana.org/assignments/arp-parameters
public enum HType : byte
{
Ethernet = 1,
ExperimentalEthernet = 2,
AX25 = 3,
ProNET = 4,
Chaos = 5,
Serial = 20,
IEEE1394_1995 = 24,
ARPSec = 30,
IPSecTunnel = 31,
Infiniband = 32
}
public DhcpFormat(BootType bootType)
{
op = (byte)bootType;
chaddr = new byte[HardwareAddressLength];
sname = new byte[ServerNameLength];
file = new byte[BootFileLength];
cookie = DhcpCookie;
options = new byte[MaxOptionsLength];
flags = 0x8000; // Request broadcast responses
optionsUsedLength = 0;
base();
}
public DhcpFormat(MessageType messageType)
: this(GetBootType(messageType))
{
AddOption(DhcpMessageType.Create((byte)messageType));
}
public int Size
{
get { return MinLength + optionsUsedLength + EndMarkerLength; }
}
public BootType BootMessageType
{
get { return (BootType)op; }
}
public IPv4 ClientIPAddress
{
get { return new IPv4(ciaddr); }
set { ciaddr = (uint)value; }
}
public IPv4 YourIPAddress
{
get { return new IPv4(yiaddr); }
set { yiaddr = (uint)value; }
}
public IPv4 NextServerIPAddress
{
get { return new IPv4(siaddr); }
set { siaddr = (uint)value; }
}
public IPv4 RelayAgentIPAddress
{
get { return new IPv4(giaddr); }
set { giaddr = (uint)value; }
}
public byte Hops
{
get { return hops; }
set { hops = value; }
}
public uint TransactionID
{
get { return xid; }
set { xid = value; }
}
public ushort TransactionSeconds
{
get { return secs; }
set { secs = value; }
}
public ushort Flags
{
get { return flags; }
set { flags = value; }
}
public string! ServerName
{
get { return BytesToString(sname); }
set { StringToBytes(value, sname); }
}
public string! BootFile
{
get { return BytesToString(file); }
set { StringToBytes(value, file); }
}
public void SetHardwareAddress (EthernetAddress ea)
{
hlen = 6;
htype = (byte)HType.Ethernet;
chaddr = new byte[HardwareAddressLength];
ea.CopyOut(chaddr, 0);
}
public EthernetAddress GetHardwareAddress()
{
if (htype != (byte)HType.Ethernet)
{
// XXX Throw some nasty exception
}
return EthernetAddress.ParseBytes(chaddr, 0);
}
public SortedList! GetOptions()
{
return DhcpOptionParser.Parse(options, 0, this.optionsUsedLength);
}
public void AddOption(IDhcpOption! option)
{
int newLength = option.PayloadLength + 2 + optionsUsedLength;
if (newLength > this.options.Length)
{
newLength = (newLength + 64) & ~3;
byte [] newOptions = new byte [newLength];
this.options.CopyTo(newOptions, 0);
this.options = newOptions;
}
option.Pack(this.options, ref optionsUsedLength);
}
private static String! BytesToString(byte []! bytes)
{
// Poorman's StringBuilder
char[] chars = new char[bytes.Length];
int i;
for (i = 0; i < bytes.Length; i++)
{
if (bytes[i] == 0)
break;
chars[i] = (char)bytes[i];
}
return new String(chars, 0, i);
}
private static void StringToBytes(string! from, byte []! to)
{
int end = Math.Min(from.Length, to.Length);
for (int i = 0; i < end; i++)
{
to[i] = (byte)from[i];
}
// Zero-terminate
if (end != to.Length)
{
to[end] = 0;
}
}
public static DhcpFormat! Parse(IBuffer! buffer)
{
DhcpFormat p = new DhcpFormat(BootType.NotSpecified);
p.optionsUsedLength = 0;
if (buffer.Available < DhcpFormat.MinLength)
{
throw new InvalidDhcpFormatException("Format less than minimum size");
}
buffer.Read8(out p.op);
if (p.op != (byte)BootType.Request &&
p.op != (byte)BootType.Reply)
{
throw new InvalidDhcpFormatException("Bad Type (op = {0})", p.op);
}
buffer.Read8(out p.htype);
// No check
buffer.Read8(out p.hlen);
if (p.hlen > HardwareAddressLength)
{
throw new InvalidDhcpFormatException("Bad address length (hlen {0})",
p.hlen);
}
buffer.Read8(out p.hops);
// No check
buffer.ReadNet32(out p.xid);
buffer.ReadNet16(out p.secs);
buffer.ReadNet16(out p.flags);
buffer.ReadNet32(out p.ciaddr);
buffer.ReadNet32(out p.yiaddr);
buffer.ReadNet32(out p.siaddr);
buffer.ReadNet32(out p.giaddr);
buffer.ReadBytes(p.chaddr, 0, HardwareAddressLength);
buffer.ReadBytes(p.sname, 0, ServerNameLength);
buffer.ReadBytes(p.file, 0, BootFileLength);
buffer.ReadNet32(out p.cookie);
if (p.cookie != DhcpCookie)
{
throw new InvalidDhcpFormatException("Bad cookie (0x{0x:x8})",
p.cookie);
}
if (buffer.Available > p.options.Length)
{
p.options = new byte [buffer.Available];
}
p.optionsUsedLength = buffer.Available;
buffer.ReadBytes(p.options, 0, buffer.Available);
return p;
}
private static void Write(byte[]! buffer, ref int offset, byte value)
{
buffer[offset++] = value;
}
private static void Write(byte[]! buffer, ref int offset, ushort value)
{
buffer[offset++] = (byte)(value >> 8);
buffer[offset++] = (byte)(value);
}
private static void Write(byte[]! buffer, ref int offset, uint value)
{
buffer[offset++] = (byte)(value >> 24);
buffer[offset++] = (byte)(value >> 16);
buffer[offset++] = (byte)(value >> 8);
buffer[offset++] = (byte)(value);
}
private static void Write(byte[]! buffer,
ref int offset,
byte[]! values,
int valuesLength)
{
for (int i = 0; i < valuesLength; i++)
{
buffer[offset++] = values[i];
}
}
public int Write(byte[]! buffer, int offset)
{
Write(buffer, ref offset, this.op);
Write(buffer, ref offset, this.htype);
Write(buffer, ref offset, this.hlen);
Write(buffer, ref offset, this.hops);
Write(buffer, ref offset, this.xid);
Write(buffer, ref offset, this.secs);
Write(buffer, ref offset, this.flags);
Write(buffer, ref offset, this.ciaddr);
Write(buffer, ref offset, this.yiaddr);
Write(buffer, ref offset, this.siaddr);
Write(buffer, ref offset, this.giaddr);
Write(buffer, ref offset, this.chaddr, this.chaddr.Length);
Write(buffer, ref offset, this.sname, this.sname.Length);
Write(buffer, ref offset, this.file, this.file.Length);
Write(buffer, ref offset, this.cookie);
Write(buffer, ref offset, this.options, this.optionsUsedLength);
Write(buffer, ref offset, EndMarker);
return offset;
}
public static bool IsRequestMessage(MessageType m)
{
return (m == MessageType.Discover || m == MessageType.Request ||
m == MessageType.Decline || m == MessageType.Release ||
m == MessageType.Inform);
}
public static bool IsResponseMessage(MessageType m)
{
return (m == MessageType.Offer || m == MessageType.Ack ||
m == MessageType.Nak);
}
public static BootType GetBootType(MessageType m)
{
return IsRequestMessage(m) ? BootType.Request : BootType.Reply;
}
}
}