422 lines
17 KiB
C#
422 lines
17 KiB
C#
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/*
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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 2010 Chris Morgan <chmorgan@gmail.com>
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*/
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using System;
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using System.Collections;
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using System.Collections.Generic;
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using System.Runtime.InteropServices;
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using System.IO;
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using System.Text;
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using System.Linq;
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using PacketDotNet.Utils;
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using MiscUtil.Conversion;
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namespace PacketDotNet
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{
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namespace Ieee80211
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{
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/// <summary>
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/// .Net analog of a ieee80211_radiotap_header from airpcap.h
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/// </summary>
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public class RadioPacket : InternetLinkLayerPacket
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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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/// Version 0. Only increases for drastic changes, introduction of compatible
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/// new fields does not count.
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/// </summary>
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public byte Version { get; set; }
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private byte VersionBytes
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{
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get
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{
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return header.Bytes[header.Offset + RadioFields.VersionPosition];
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}
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set
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{
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header.Bytes[header.Offset + RadioFields.VersionPosition] = value;
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}
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}
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/// <summary>
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/// Length of the whole header in bytes, including it_version, it_pad, it_len
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/// and data fields
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/// </summary>
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public UInt16 Length {get; set;}
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private UInt16 LengthBytes
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{
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get
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{
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return EndianBitConverter.Little.ToUInt16(header.Bytes,
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header.Offset + RadioFields.LengthPosition);
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}
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set
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{
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EndianBitConverter.Little.CopyBytes(value,
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header.Bytes,
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header.Offset + RadioFields.LengthPosition);
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}
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}
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/// <summary>
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/// Returns an array of UInt32 bitmap entries. Each bit in the bitmap indicates
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/// which fields are present. Set bit 31 (0x8000000)
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/// to extend the bitmap by another 32 bits. Additional extensions are made
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/// by setting bit 31.
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/// </summary>
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private UInt32[] Present {get; set;}
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private UInt32[] ReadPresentFields()
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{
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// make an array of the bitmask fields
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// the highest bit indicates whether other bitmask fields follow
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// the current field
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var bitmaskFields = new List<UInt32>();
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UInt32 bitmask = EndianBitConverter.Little.ToUInt32(header.Bytes,
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header.Offset + RadioFields.PresentPosition);
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bitmaskFields.Add(bitmask);
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int bitmaskOffsetInBytes = 4;
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while ((bitmask & (1 << 31)) == 1)
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{
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// retrieve the next field
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bitmask = EndianBitConverter.Little.ToUInt32(header.Bytes,
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header.Offset + RadioFields.PresentPosition + bitmaskOffsetInBytes);
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bitmaskFields.Add(bitmask);
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bitmaskOffsetInBytes += 4;
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}
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return bitmaskFields.ToArray();
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}
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/// <summary>
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/// Initializes a new instance of the <see cref="PacketDotNet.Ieee80211.RadioPacket"/> class.
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/// </summary>
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public RadioPacket()
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{
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Present = new UInt32[1];
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RadioTapFields = new SortedDictionary<RadioTapType, RadioTapField>();
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Length = (ushort)RadioFields.DefaultHeaderLength;
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}
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internal RadioPacket (ByteArraySegment bas)
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{
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log.Debug ("");
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// slice off the header portion
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header = new ByteArraySegment (bas);
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header.Length = RadioFields.DefaultHeaderLength;
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Version = VersionBytes;
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Length = LengthBytes;
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// update the header size based on the headers packet length
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header.Length = Length;
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Present = ReadPresentFields();
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RadioTapFields = ReadRadioTapFields();
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//Before we attempt to parse the payload we need to work out if
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//the FCS was valid and if it will be present at the end of the frame
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FlagsRadioTapField flagsField = this[RadioTapType.Flags] as FlagsRadioTapField;
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payloadPacketOrData = ParseEncapsulatedBytes(header.EncapsulatedBytes(), flagsField);
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}
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/// <summary cref="Packet.ToString(StringOutputType)" />
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public override string ToString(StringOutputType outputFormat)
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{
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var buffer = new StringBuilder();
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string color = "";
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string colorEscape = "";
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if (outputFormat == StringOutputType.Colored || outputFormat == StringOutputType.VerboseColored)
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{
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color = Color;
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colorEscape = AnsiEscapeSequences.Reset;
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}
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if (outputFormat == StringOutputType.Normal || outputFormat == StringOutputType.Colored)
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{
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// build the output string
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buffer.AppendFormat("{0}[Ieee80211RadioPacket: Version={2}, Length={3}, Present[0]=0x{4:x}]{1}",
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color,
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colorEscape,
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Version,
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Length,
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Present[0]);
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}
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if (outputFormat == StringOutputType.Verbose || outputFormat == StringOutputType.VerboseColored)
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{
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// collect the properties and their value
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Dictionary<string, string> properties = new Dictionary<string, string>();
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properties.Add("version", Version.ToString());
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properties.Add("length", Length.ToString());
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properties.Add("present", " (0x" + Present[0].ToString("x") + ")");
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var radioTapFields = this.RadioTapFields;
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foreach (var r in radioTapFields)
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{
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properties.Add(r.Value.FieldType.ToString(),
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r.Value.ToString());
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}
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// calculate the padding needed to right-justify the property names
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int padLength = Utils.RandomUtils.LongestStringLength(new List<string>(properties.Keys));
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// build the output string
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buffer.AppendLine("Ieee80211RadioPacket");
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foreach (var property in properties)
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{
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buffer.AppendLine("TAP: " + property.Key.PadLeft(padLength) + " = " + property.Value);
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}
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buffer.AppendLine("TAP:");
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}
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// append the base output
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buffer.Append(base.ToString(outputFormat));
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return buffer.ToString();
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}
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/// <summary>
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/// Add the specified field to the packet.
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/// </summary>
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/// <param name='field'>
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/// Field to be added
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/// </param>
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public void Add(RadioTapField field)
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{
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RadioTapFields[field.FieldType] = field;
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Length += field.Length;
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var presenceBit = (int)field.FieldType;
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var presenceField = (presenceBit / 32);
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if(Present.Length <= presenceField)
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{
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var newPresentFields = new UInt32[presenceField];
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Array.Copy(Present, newPresentFields, Present.Length);
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//set bit 31 to true for every present field except the last one
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for(int i = 0; i < newPresentFields.Length - 1; i++)
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{
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newPresentFields[i] |= 0x80000000;
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}
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Present = newPresentFields;
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}
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Present[presenceField] |= (UInt32)(1 << presenceBit);
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}
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/// <summary>
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/// Removes a field of the specified type if one is present in the packet.
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/// </summary>
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/// <param name='fieldType'>
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/// Field type.
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/// </param>
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public void Remove(RadioTapType fieldType)
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{
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RadioTapField field;
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if(RadioTapFields.TryGetValue(fieldType, out field))
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{
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RadioTapFields.Remove(fieldType);
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Length -= field.Length;
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var presenceBit = (int)field.FieldType;
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var presenceField = (presenceBit / 32);
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Present[presenceField] &= (UInt32)~(1 << presenceBit);
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}
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}
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/// <summary>
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/// Checks for the presence of a field of the specified type in the packet.
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/// </summary>
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/// <param name='fieldType'>
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/// The field type to check for.
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/// </param>
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/// <returns><c>true</c> if the packet contains a field of the specified type; otherwise, <c>false</c>.</returns>
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public bool Contains(RadioTapType fieldType)
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{
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return RadioTapFields.ContainsKey(fieldType);
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}
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/// <summary>
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/// Gets the <see cref="PacketDotNet.Ieee80211.RadioTapField"/> with the specified type, or null if the
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/// field is not in the packet.
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/// </summary>
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/// <param name='type'>
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/// Radio Tap field type
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/// </param>
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public RadioTapField this[RadioTapType type]
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{
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get
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{
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RadioTapField field;
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RadioTapFields.TryGetValue(type, out field);
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return field;
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}
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}
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/// <summary>
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/// Array of radio tap fields
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/// </summary>
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private SortedDictionary<RadioTapType, RadioTapField> RadioTapFields { get; set; }
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private byte[] UnhandledFieldBytes {get; set;}
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private SortedDictionary<RadioTapType, RadioTapField> ReadRadioTapFields()
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{
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var bitmasks = Present;
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var retval = new SortedDictionary<RadioTapType, RadioTapField>();
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int bitIndex = 0;
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// create a binary reader that points to the memory immediately after the bitmasks
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var offset = header.Offset +
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RadioFields.PresentPosition +
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(bitmasks.Length) * Marshal.SizeOf (typeof(UInt32));
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var br = new BinaryReader (new MemoryStream (header.Bytes,
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offset,
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(int)(Length - offset)));
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// now go through each of the bitmask fields looking at the least significant
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// bit first to retrieve each field
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foreach (var bmask in bitmasks)
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{
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int[] bmaskArray = new int[1];
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bmaskArray [0] = (int)bmask;
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var ba = new BitArray (bmaskArray);
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bool unhandledFieldFound = false;
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// look at all of the bits, note we don't want to consider the
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// highest bit since that indicates another bitfield that follows
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for (int x = 0; x < 31; x++)
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{
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if (ba [x] == true)
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{
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var field = RadioTapField.Parse (bitIndex, br);
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if (field != null)
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{
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retval[field.FieldType] = field;
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}
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else
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{
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//We have found a field that we dont handle. As we dont know how big
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//it is we can't handle any fields after it. We will just copy
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//the rest of the data around as a lump
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unhandledFieldFound = true;
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break;
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}
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}
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bitIndex++;
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}
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if(unhandledFieldFound)
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{
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break;
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}
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}
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//this will read the rest of the bytes. We pass in max value because we dont know how
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//much there is but this will ensure we get up to the end of the buffer
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UnhandledFieldBytes = br.ReadBytes(UInt16.MaxValue);
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return retval;
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}
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/// <summary>
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/// Called to ensure that field values are updated before
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/// the packet bytes are retrieved
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/// </summary>
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public override void UpdateCalculatedValues()
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{
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if ((header == null) || (header.Length < Length))
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{
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//the backing buffer isnt big enough to accommodate the info elements so we need to resize it
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header = new ByteArraySegment (new Byte[Length]);
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}
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VersionBytes = Version;
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LengthBytes = Length;
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var index = RadioFields.PresentPosition;
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foreach(var presentField in Present)
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{
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EndianBitConverter.Little.CopyBytes(presentField,
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header.Bytes,
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header.Offset + index);
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index += RadioFields.PresentLength;
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}
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foreach(var field in RadioTapFields)
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{
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//then copy the field data to the appropriate index
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field.Value.CopyTo(header.Bytes, header.Offset + index);
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index += field.Value.Length;
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
if((UnhandledFieldBytes != null) && (UnhandledFieldBytes.Length > 0))
|
|||
|
|
{
|
|||
|
|
Array.Copy(UnhandledFieldBytes, 0, header.Bytes, header.Offset + index, UnhandledFieldBytes.Length);
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
internal static PacketOrByteArraySegment ParseEncapsulatedBytes (ByteArraySegment payload, FlagsRadioTapField flagsField)
|
|||
|
|
{
|
|||
|
|
var payloadPacketOrData = new PacketOrByteArraySegment ();
|
|||
|
|
MacFrame frame = null;
|
|||
|
|
|
|||
|
|
if (flagsField != null)
|
|||
|
|
{
|
|||
|
|
bool fcsPresent = ((flagsField.Flags & RadioTapFlags.FcsIncludedInFrame) == RadioTapFlags.FcsIncludedInFrame);
|
|||
|
|
|
|||
|
|
if (fcsPresent)
|
|||
|
|
{
|
|||
|
|
frame = MacFrame.ParsePacketWithFcs (payload);
|
|||
|
|
}
|
|||
|
|
else
|
|||
|
|
{
|
|||
|
|
frame = MacFrame.ParsePacket (payload);
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
else
|
|||
|
|
{
|
|||
|
|
frame = MacFrame.ParsePacket (payload);
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
if (frame == null)
|
|||
|
|
{
|
|||
|
|
payloadPacketOrData.TheByteArraySegment = payload;
|
|||
|
|
}
|
|||
|
|
else
|
|||
|
|
{
|
|||
|
|
payloadPacketOrData.ThePacket = frame;
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
return payloadPacketOrData;
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
}
|