/// <summary>
/// Attempts to parse raw data into a structured packet
/// </summary>
/// <param name="buffer">Raw data to parse</param>
/// <param name="packet">Parsed packet</param>
/// <param name="count">The length of the packet in bytes</param>
/// <param name="index">The index into the buffer at which the packet begins</param>
/// <returns>True if parsing was successful, false if it is not.</returns>
internal static bool TryParse(byte[] buffer, int index, int count, out LLC packet)
{
try
{
if (count < MinimumParseableBytes)
{
packet = null;
return(false);
}
using (var ms = new MemoryStream(buffer, index, count, false))
{
using (var br = new BinaryReader(ms))
{
var dsap = br.ReadByte();
var ssap = br.ReadByte();
byte commandControl = 0;
UInt16 responseControl = 0;
if (dsap % 2 == 0)
{
commandControl = br.ReadByte();
}
else if (count < 4)
{
packet = null;
return(false);
}
else
{
responseControl = br.ReadUInt16();
}
SNAP payloadSNAP;
if (SNAP.TryParse(
buffer,
index + (int)br.BaseStream.Position,
(int)(count - br.BaseStream.Position),
out payloadSNAP))
{
packet = new LLC <SNAP> {
Payload = payloadSNAP
};
}
else
{
Generic payloadGeneric;
Generic.TryParse(
buffer,
index + (int)br.BaseStream.Position,
(int)(count - br.BaseStream.Position),
out payloadGeneric);
// This can never fail, so I'm not checking the output
packet = new LLC <Generic> {
Payload = payloadGeneric
};
}
packet.DSAP = dsap;
packet.SSAP = ssap;
packet.CommandControl = commandControl;
packet.ResponseControl = responseControl;
return(true);
}
}
}
catch (Exception)
{
packet = null;
return(false);
}
}
/// <summary>
/// Attempts to parse raw data into a structured packet
/// </summary>
/// <param name="buffer">Raw data to parse</param>
/// <param name="packet">Parsed packet</param>
/// <param name="count">The length of the packet in bytes</param>
/// <param name="index">The index into the buffer at which the packet begins</param>
/// <returns>True if parsing was successful, false if it is not.</returns>
internal static bool TryParse(byte[] buffer, int index, int count, out LLC packet)
{
try
{
if (count < MinimumParseableBytes)
{
packet = null;
return false;
}
using (var ms = new MemoryStream(buffer, index, count, false))
{
using (var br = new BinaryReader(ms))
{
var dsap = br.ReadByte();
var ssap = br.ReadByte();
byte commandControl = 0;
UInt16 responseControl = 0;
if (dsap % 2 == 0)
{
commandControl = br.ReadByte();
}
else if (count < 4)
{
packet = null;
return false;
}
else
{
responseControl = br.ReadUInt16();
}
SNAP payloadSNAP;
if (SNAP.TryParse(
buffer,
index + (int)br.BaseStream.Position,
(int)(count - br.BaseStream.Position),
out payloadSNAP))
{
packet = new LLC<SNAP> { Payload = payloadSNAP };
}
else
{
Generic payloadGeneric;
Generic.TryParse(
buffer,
index + (int)br.BaseStream.Position,
(int)(count - br.BaseStream.Position),
out payloadGeneric);
// This can never fail, so I'm not checking the output
packet = new LLC<Generic> { Payload = payloadGeneric };
}
packet.DSAP = dsap;
packet.SSAP = ssap;
packet.CommandControl = commandControl;
packet.ResponseControl = responseControl;
return true;
}
}
}
catch (Exception)
{
packet = null;
return false;
}
}
/// <summary>
/// Attempts to parse raw data into a structured packet
/// </summary>
/// <param name="buffer">Raw data to parse</param>
/// <param name="packet">Parsed packet</param>
/// <param name="count">The length of the packet in bytes</param>
/// <param name="index">The index into the buffer at which the packet begins</param>
/// <returns>True if parsing was successful, false if it is not.</returns>
internal static bool TryParse(byte[] buffer, int index, int count, out IEEE802_11 packet)
{
try
{
if (count < MinimumParseableBytes)
{
packet = null;
return(false);
}
using (var ms = new MemoryStream(buffer, index, count, false))
{
using (var br = new BinaryReader(ms))
{
var frameControlVersionTypeAndSubtype = new BitVector32(br.ReadByte());
var frameControlFlags = new BitVector32(br.ReadByte());
var durationID = br.ReadUInt16();
var toDS = frameControlFlags[1];
var fromDS = frameControlFlags[2];
byte[] destination;
byte[] source;
byte[] bssid;
byte[] receiver = null;
byte[] transmitter = null;
UInt16 sequenceControl;
if (!toDS)
{
destination = br.ReadBytes(6);
if (!fromDS)
{
source = br.ReadBytes(6);
bssid = br.ReadBytes(6);
}
else
{
bssid = br.ReadBytes(6);
source = br.ReadBytes(6);
}
sequenceControl = br.ReadUInt16(); //Was NTHO, wireshark disagrees
}
else
{
if (!fromDS)
{
bssid = br.ReadBytes(6);
source = br.ReadBytes(6);
destination = br.ReadBytes(6);
sequenceControl = br.ReadUInt16(); //Was NTHO, wireshark disagrees
}
else
{
receiver = br.ReadBytes(6);
transmitter = br.ReadBytes(6);
bssid = transmitter; //Per airdecap-ng
destination = br.ReadBytes(6);
sequenceControl = br.ReadUInt16(); //Was NTHO, wireshark disagrees
source = br.ReadBytes(6);
}
}
var frameType =
frameControlVersionTypeAndSubtype[BitVector32.CreateSection(3, BitVector32.CreateSection(3))
];
var subType =
frameControlVersionTypeAndSubtype[
BitVector32.CreateSection(15, BitVector32.CreateSection(15))];
byte[] qosControl = null;
if (frameType == (int)FrameTypes.Data && subType == (int)DataSubTypes.QoS)
{
qosControl = br.ReadBytes(2);
}
var isProtected = frameControlFlags[64];
byte[] ccmp_WEP_Data = null;
if (isProtected)
{
if (count - br.BaseStream.Position < 4)
{
packet = null;
return(false);
}
var firstFour = br.ReadBytes(4);
if (firstFour[3] == 0)
{
ccmp_WEP_Data = firstFour;
}
else
{
if (count - br.BaseStream.Position < 4)
{
packet = null;
return(false);
}
ccmp_WEP_Data = new byte[8];
firstFour.CopyTo(ccmp_WEP_Data, 0);
br.ReadBytes(4).CopyTo(ccmp_WEP_Data, 4);
}
}
var isWep = isProtected && ccmp_WEP_Data?.Length == 4;
if (count - br.BaseStream.Position - (isWep ? 4 : 0) < 0)
{
packet = null;
return(false);
}
var unsafePayloadLen = count - (int)br.BaseStream.Position - (isWep ? 4 : 0);
var safePayloadLen = Math.Max(0, unsafePayloadLen);
packet = null;
if (frameType == (int)FrameTypes.Data && ((subType & 4) != 1) && !isProtected)
{
LLC payload;
if (LLC.TryParse(buffer, index + (int)br.BaseStream.Position, safePayloadLen, out payload))
{
packet = new IEEE802_11 <LLC> {
Payload = payload
};
}
}
else if (frameType == (int)FrameTypes.Management && subType == (int)ManagementSubTypes.Beacon)
{
Beacon802_11 payload;
if (Beacon802_11.TryParse(
buffer,
index + (int)br.BaseStream.Position,
safePayloadLen,
out payload))
{
packet = new IEEE802_11 <Beacon802_11> {
Payload = payload
};
}
}
if (packet == null)
{
Generic payload;
Generic.TryParse(buffer, index + (int)br.BaseStream.Position, safePayloadLen, out payload);
// This can never fail, so I'm not checking the output
packet = new IEEE802_11 <Generic> {
Payload = payload
};
}
br.BaseStream.Seek(packet.Payload.Length(), SeekOrigin.Current);
UInt32 wep_ICV = 0;
if (isWep)
{
wep_ICV = ByteOrder.NetworkToHostOrder(br.ReadUInt32());
}
packet.FrameControlVersionTypeAndSubtype = frameControlVersionTypeAndSubtype;
packet.FrameControlFlags = frameControlFlags;
packet.DurationID = durationID;
packet.Destination = destination;
packet.Source = source;
packet.BSSID = bssid;
packet.SequenceControl = sequenceControl;
packet.Receiver = receiver;
packet.Transmitter = transmitter;
packet.QosControl = qosControl;
packet.CCMP_WEP_Data = ccmp_WEP_Data;
packet.WEP_ICV = wep_ICV;
if (br.BaseStream.Position == count - 4)
{
packet.FrameCheckSequence = br.ReadUInt32();
}
return(true);
}
}
}
catch (Exception)
{
packet = null;
return(false);
}
}
