504 lines
18 KiB
C#
504 lines
18 KiB
C#
/*
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This file is part of PacketDotNet
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PacketDotNet is free software: you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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PacketDotNet is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with PacketDotNet. If not, see <http://www.gnu.org/licenses/>.
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*/
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/*
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* Copyright 2009 Chris Morgan <chmorgan@gmail.com>
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*/
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using System;
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using System.IO;
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using System.Text;
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using PacketDotNet.Utils;
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using System.Linq;
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namespace PacketDotNet
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{
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/// <summary>
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/// Base class for all packet types.
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/// Defines helper methods and accessors for the architecture that underlies how
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/// packets interact and store their data.
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/// </summary>
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public abstract class Packet
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{
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// NOTE: No need to warn about lack of use, the compiler won't
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// put any calls to 'log' here but we need 'log' to exist to compile
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#pragma warning disable 0169, 0649
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private static readonly ILogInactive log;
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#pragma warning restore 0169, 0649
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/// <summary>
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/// Used internally when building new packet dissectors
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/// </summary>
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protected ByteArraySegment header;
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/// <summary>
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/// Used internally when building new packet dissectors
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/// </summary>
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protected PacketOrByteArraySegment payloadPacketOrData = new PacketOrByteArraySegment();
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/// <summary>
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/// The parent packet. Accessible via the 'ParentPacket' property
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/// </summary>
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private Packet parentPacket;
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/// <summary>
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/// Gets the total length of the packet.
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/// Recursively finds the length of this packet and all of the packets
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/// encapsulated by this packet
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/// </summary>
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/// <value>
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/// The total length of the packet.
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/// </value>
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protected int TotalPacketLength
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{
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get
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{
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int totalLength = 0;
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totalLength += header.Length;
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if(payloadPacketOrData.Type == PayloadType.Bytes)
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{
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totalLength += payloadPacketOrData.TheByteArraySegment.Length;
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} else if(payloadPacketOrData.Type == PayloadType.Packet)
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{
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totalLength += payloadPacketOrData.ThePacket.TotalPacketLength;
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}
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return totalLength;
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}
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}
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/// <value>
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/// Returns true if we already have a contiguous byte[] in either
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/// of these conditions:
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///
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/// - This packet's header byte[] and payload byte[] are the same instance
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/// or
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/// - This packet's header byte[] and this packet's payload packet
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/// are the same instance and the offsets indicate that the bytes
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/// are contiguous
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/// </value>
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protected bool SharesMemoryWithSubPackets
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{
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get
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{
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log.Debug("");
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switch(payloadPacketOrData.Type)
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{
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case PayloadType.Bytes:
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// is the byte array payload the same byte[] and does the offset indicate
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// that the bytes are contiguous?
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if((header.Bytes == payloadPacketOrData.TheByteArraySegment.Bytes) &&
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((header.Offset + header.Length) == payloadPacketOrData.TheByteArraySegment.Offset))
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{
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log.Debug("PayloadType.Bytes returning true");
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return true;
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} else
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{
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log.Debug("PayloadType.Bytes returning false");
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return false;
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}
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case PayloadType.Packet:
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// is the byte array payload the same as the payload packet header and does
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// the offset indicate that the bytes are contiguous?
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if((header.Bytes == payloadPacketOrData.ThePacket.header.Bytes) &&
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((header.Offset + header.Length) == payloadPacketOrData.ThePacket.header.Offset))
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{
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// and does the sub packet share memory with its sub packets?
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var retval = payloadPacketOrData.ThePacket.SharesMemoryWithSubPackets;
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log.DebugFormat("PayloadType.Packet retval {0}", retval);
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return retval;
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} else
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{
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log.Debug("PayloadType.Packet returning false");
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return false;
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}
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case PayloadType.None:
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// no payload data or packet thus we must share memory with
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// our non-existent sub packets
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log.Debug("PayloadType.None, returning true");
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return true;
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default:
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throw new System.NotImplementedException();
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}
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}
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}
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/// <summary>
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/// The packet that is carrying this one
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/// </summary>
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public virtual Packet ParentPacket
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{
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get { return parentPacket; }
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set { parentPacket = value; }
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}
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/// <value>
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/// Returns a
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/// </value>
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public virtual byte[] Header
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{
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get { return this.header.ActualBytes(); }
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}
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/// <summary>
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/// Packet that this packet carries if one is present.
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/// Note that the packet MAY have a null PayloadPacket but
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/// a non-null PayloadData
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/// </summary>
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public virtual Packet PayloadPacket
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{
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get { return payloadPacketOrData.ThePacket; }
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set
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{
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if (this == value)
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throw new InvalidOperationException("A packet cannot have itself as its payload.");
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payloadPacketOrData.ThePacket = value;
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payloadPacketOrData.ThePacket.ParentPacket = this;
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}
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}
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/// <summary>
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/// Payload byte[] if one is present.
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/// Note that the packet MAY have a null PayloadData but a
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/// non-null PayloadPacket
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/// </summary>
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public byte[] PayloadData
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{
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get
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{
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if(payloadPacketOrData.TheByteArraySegment == null)
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{
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log.Debug("returning null");
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return null;
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} else
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{
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var retval = payloadPacketOrData.TheByteArraySegment.ActualBytes();
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log.DebugFormat("retval.Length: {0}", retval.Length);
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return retval;
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}
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}
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set
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{
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log.DebugFormat("value.Length {0}", value.Length);
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payloadPacketOrData.TheByteArraySegment = new ByteArraySegment(value, 0, value.Length);
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}
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}
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/// <summary>
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/// byte[] containing this packet and its payload
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/// NOTE: Use 'public virtual ByteArraySegment BytesHighPerformance' for highest performance
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/// </summary>
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public virtual byte[] Bytes
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{
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get
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{
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log.Debug("");
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// Retrieve the byte array container
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var ba = BytesHighPerformance;
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// ActualBytes() will copy bytes if necessary but will avoid a copy in the
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// case where our offset is zero and the byte[] length matches the
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// encapsulated Length
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return ba.ActualBytes();
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}
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}
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/// <value>
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/// The option to return a ByteArraySegment means that this method
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/// is higher performance as the data can start at an offset other than
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/// the first byte.
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/// </value>
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public virtual ByteArraySegment BytesHighPerformance
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{
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get
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{
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log.Debug("");
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// ensure calculated values are properly updated
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//RecursivelyUpdateCalculatedValues();
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// if we share memory with all of our sub packets we can take a
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// higher performance path to retrieve the bytes
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if(SharesMemoryWithSubPackets)
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{
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// The high performance path that is often taken because it is called on
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// packets that have not had their header, or any of their sub packets, resized
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var newByteArraySegment = new ByteArraySegment(header.Bytes,
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header.Offset,
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header.BytesLength - header.Offset);
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log.DebugFormat("SharesMemoryWithSubPackets, returning byte array {0}",
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newByteArraySegment.ToString());
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return newByteArraySegment;
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} else // need to rebuild things from scratch
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{
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log.Debug("rebuilding the byte array");
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var ms = new MemoryStream();
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// TODO: not sure if this is a performance gain or if
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// the compiler is smart enough to not call the get accessor for Header
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// twice, once when retrieving the header and again when retrieving the Length
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var theHeader = Header;
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ms.Write(theHeader, 0, theHeader.Length);
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payloadPacketOrData.AppendToMemoryStream(ms);
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var newBytes = ms.ToArray();
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return new ByteArraySegment(newBytes, 0, newBytes.Length);
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}
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}
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}
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/// <summary>
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/// Constructor
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/// </summary>
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public Packet()
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{
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}
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/// <summary>
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/// Parse bytes into a packet
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/// </summary>
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/// <param name="LinkLayer">
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/// A <see cref="LinkLayers"/>
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/// </param>
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/// <param name="PacketData">
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/// A <see cref="System.Byte"/>
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/// </param>
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/// <returns>
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/// A <see cref="Packet"/>
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/// </returns>
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public static Packet ParsePacket(LinkLayers LinkLayer,
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byte[] PacketData)
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{
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Packet p;
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var bas = new ByteArraySegment(PacketData);
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log.DebugFormat("LinkLayer {0}", LinkLayer);
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switch(LinkLayer)
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{
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case LinkLayers.Ethernet:
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p = new EthernetPacket(bas);
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break;
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case LinkLayers.LinuxSLL:
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p = new LinuxSLLPacket(bas);
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break;
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case LinkLayers.Ppp:
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p = new PPPPacket(bas);
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break;
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case LinkLayers.Ieee80211:
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p = Ieee80211.MacFrame.ParsePacket(bas);
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break;
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case LinkLayers.Ieee80211_Radio:
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p = new Ieee80211.RadioPacket(bas);
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break;
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case LinkLayers.PerPacketInformation:
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p = new Ieee80211.PpiPacket(bas);
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break;
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default:
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throw new System.NotImplementedException("LinkLayer of " + LinkLayer + " is not implemented");
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}
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return p;
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}
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/// <summary>
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/// Used to ensure that values like checksums and lengths are
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/// properly updated
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/// </summary>
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public void RecursivelyUpdateCalculatedValues(EthernetPacketType[] supportedEthernetPacketTypes = null, IPProtocolType[] supportedIPProtocols = null)
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{
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RecursivelyUpdateCalculatedValues(0, supportedEthernetPacketTypes, supportedIPProtocols, false);
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}
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protected void RecursivelyUpdateCalculatedValues(int depth, EthernetPacketType[] supportedEthernetPacketTypes, IPProtocolType[] supportedIPProtocols, bool skipLevel)
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{
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// call the possibly overridden method
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if(!skipLevel)
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{
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UpdateCalculatedValues();
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}
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// if the packet contains another packet, try it
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if(payloadPacketOrData.Type == PayloadType.Packet && payloadPacketOrData.ThePacket != this)
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{
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var skip = (this is EthernetPacket && !supportedEthernetPacketTypes.Contains(((EthernetPacket)this).Type))
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|| (this is IpPacket && !supportedIPProtocols.Contains(((IpPacket)this).NextHeader));
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payloadPacketOrData.ThePacket.RecursivelyUpdateCalculatedValues(depth +1, supportedEthernetPacketTypes, supportedIPProtocols, skip);
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}
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}
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/// <summary>
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/// Called to ensure that calculated values are updated before
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/// the packet bytes are retrieved
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///
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/// Classes should override this method to update things like
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/// checksums and lengths that take too much time or are too complex
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/// to update for each packet parameter change
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/// </summary>
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public virtual void UpdateCalculatedValues()
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{ }
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/// <summary>Output this packet as a readable string</summary>
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public override System.String ToString()
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{
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return ToString(StringOutputType.Normal);
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}
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/// <summary cref="Packet.ToString()">
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///
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/// Output the packet information in the specified format
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/// Normal - outputs the packet info to a single line
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/// Colored - outputs the packet info to a single line with coloring
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/// Verbose - outputs detailed info about the packet
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/// VerboseColored - outputs detailed info about the packet with coloring
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/// </summary>
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/// <param name="outputFormat">
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/// <see cref="StringOutputType" />
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/// </param>
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public virtual string ToString(StringOutputType outputFormat)
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{
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if(payloadPacketOrData.Type == PayloadType.Packet)
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{
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return payloadPacketOrData.ThePacket.ToString(outputFormat);
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} else
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{
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return String.Empty;
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}
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}
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/// <summary>
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/// Prints the Packet PayloadData in Hex format
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/// With the 16-byte segment number, raw bytes, and parsed ascii output
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/// Ex:
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/// 0010 00 18 82 6c 7c 7f 00 c0 9f 77 a3 b0 88 64 11 00 ...1|... .w...d..
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/// </summary>
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/// <returns>
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/// A <see cref="System.String"/>
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/// </returns>
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public string PrintHex()
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{
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byte[] data = BytesHighPerformance.Bytes;
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var buffer = new StringBuilder();
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string segmentNumber = "";
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string bytes = "";
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string ascii = "";
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buffer.AppendLine("Data: ******* Raw Hex Output - length=" + data.Length + " bytes");
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buffer.AppendLine("Data: Segment: Bytes: Ascii:");
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buffer.AppendLine("Data: --------------------------------------------------------------------------");
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// parse the raw data
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for(int i = 1; i <= data.Length; i++)
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{
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// add the current byte to the bytes hex string
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bytes += (data[i-1].ToString("x")).PadLeft(2, '0') + " ";
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// add the current byte to the asciiBytes array for later processing
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if(data[i-1] < 0x21 || data[i-1] > 0x7e)
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{
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ascii += ".";
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}
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else
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{
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ascii += Encoding.ASCII.GetString(new byte[1] { data[i-1] });
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}
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// add an additional space to split the bytes into
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// two groups of 8 bytes
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if(i % 16 != 0 && i % 8 == 0)
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{
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bytes += " ";
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ascii += " ";
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}
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// append the output string
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if(i % 16 == 0)
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{
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// add the 16 byte segment number
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segmentNumber = ((((i - 16) / 16) * 10).ToString()).PadLeft(4, '0');
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// build the line
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buffer.AppendLine("Data: " + segmentNumber + " " + bytes + " " + ascii);
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// reset for the next line
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bytes = "";
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ascii = "";
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continue;
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}
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// handle the last pass
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if(i == data.Length)
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{
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// add the 16 byte segment number
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segmentNumber = (((((i - 16) / 16) + 1) * 10).ToString()).PadLeft(4, '0');
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// build the line
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buffer.AppendLine("Data: " + (segmentNumber.ToString()).PadLeft(4, '0') + " " + bytes.PadRight(49, ' ') + " " + ascii);
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}
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}
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return buffer.ToString();
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}
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/// <summary>
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/// Extract a packet of a specific type or null if a packet of the given type isn't found
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/// NOTE: a 'dynamic' return type is possible here but costs ~7.8% in performance
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/// </summary>
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/// <param name='type'>
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/// Type.
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/// </param>
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public Packet Extract(System.Type type)
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{
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var p = this;
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// search for a packet type that matches the given one
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do
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{
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if(type.IsAssignableFrom(p.GetType ()))
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{
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return p;
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}
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// move to the PayloadPacket
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p = p.PayloadPacket;
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} while(p != null);
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return null;
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}
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/// <value>
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/// Color used when generating the text description of a packet
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/// </value>
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public virtual System.String Color
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{
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get
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{
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return AnsiEscapeSequences.Black;
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}
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}
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}
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}
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