public static void ReceiveHandshake(IO.Stream stream, ref ByteField20 infoDigest)
{
// read in protocol string
byte[] protocolVersionLength = new byte[1];
if (stream.Read(protocolVersionLength, 0, protocolVersionLength.Length) != protocolVersionLength.Length)
{
throw new System.Exception("Invalid handshake protocol");
}
if (protocolVersionLength[0] != 19)
{
throw new System.Exception("Invalid handshake protocol");
}
byte[] protocolBytes = new byte[protocolVersionLength[0]];
if (stream.Read(protocolBytes, 0, protocolBytes.Length) != protocolBytes.Length)
{
throw new System.Exception("Invalid handshake protocol");
}
string protocol = System.Text.ASCIIEncoding.ASCII.GetString(protocolBytes, 0, protocolBytes.Length);
if (protocol != protocolString)
{
throw new System.Exception("Invalid handshake protocol");
}
// 8 zeros
byte[] zeroes = new byte[8];
if (stream.Read(zeroes, 0, zeroes.Length) != zeroes.Length)
{
throw new System.Exception("Invalid handshake protocol");
}
// SHA digest
stream.Read(infoDigest.Data, 0, infoDigest.Data.Length);
}
public Session(ByteField20 localPeerId)
{
mLocalPeerId = localPeerId;
if (Config.ActiveConfig.ProxyURL != "") // set web proxy
{
System.Net.WebRequest.DefaultWebProxy = new Net.WebProxy(Config.ActiveConfig.ProxyURL);
}
SetAllowUnsafeHeaderParsing20();
this.StartServer();
}
public static void SendHandshake(IO.Stream stream, ByteField20 infoDigest)
{
stream.WriteByte((byte)protocolString.Length);
stream.Write(System.Text.ASCIIEncoding.ASCII.GetBytes(protocolString), 0, protocolString.Length);
// 8 zeros
stream.Write(new byte[] { 0, 0, 0, 0, 0, 0, 0, 0 }, 0, 8);
// SHA digest
stream.Write(infoDigest.Data, 0, infoDigest.Data.Length);
}
public static void SendHandshake(IO.Stream stream, ByteField20 infoDigest)
{
stream.WriteByte((byte)protocolString.Length);
stream.Write(System.Text.ASCIIEncoding.ASCII.GetBytes(protocolString), 0, protocolString.Length);
// 8 zeros
stream.Write(new byte[] { 0, 0, 0, 0, 0, 0, 0, 0 }, 0, 8);
// SHA digest
stream.Write(infoDigest.Data, 0, infoDigest.Data.Length);
}
public Torrent FindTorrent(ByteField20 infoDigest)
{
lock (this.mTorrents)
{
foreach (Torrent torrent in this.mTorrents)
{
if (torrent.Metainfo.InfoDigest.Equals(infoDigest))
{
return(torrent);
}
}
return(null);
}
}
/// <summary>
/// Helper thread method to start the connection to peers
/// </summary>
/// <param name="state"></param>
private void StartPeerConnectionThread(System.IAsyncResult result)
{
object[] objs = (object[])result.AsyncState;
Sockets.Socket socket = (Sockets.Socket)objs[0];
PeerInformation peerinfo = (PeerInformation)objs[1];
ByteField20 infoDigest = new ByteField20(), peerId = new ByteField20();
Sockets.NetworkStream netStream;
try
{
socket.EndConnect(result);
netStream = new Sockets.NetworkStream(socket, true);
// send handshake info
PeerProtocol.SendHandshake(netStream, this.infofile.InfoDigest);
PeerProtocol.ReceiveHandshake(netStream, ref infoDigest);
PeerProtocol.SendPeerId(netStream, this.mSession.LocalPeerID);
if (!PeerProtocol.ReceivePeerId(netStream, ref peerId))
{ // NAT check
socket.Close();
return;
}
// check info digest matches and we are not attempting to connect to ourself
if (infoDigest.Equals(this.infofile.InfoDigest) && !peerId.Equals(this.mSession.LocalPeerID))
{
peerinfo.ID = peerId;
this.AddPeer(socket, netStream, peerinfo);
}
else // info digest doesn't match, close the connection
{
socket.Close();
}
}
catch (System.Exception e)
{
Config.LogException(e);
// die if the connection failed
if (socket != null)
{
socket.Close();
}
return;
}
}
/// <summary></summary>
/// <returns>True if the objects are equal</returns>
public override bool Equals(object obj)
{
if (obj is ByteField20)
{
ByteField20 sha = (ByteField20)obj;
for (int i = 0; i < this.data.Length; ++i)
{
if (this.data[i] != sha.data[i])
{
return(false);
}
}
return(true);
}
else
{
return(false);
}
}
private static ByteField20 DefaultCalculatePeerId()
{
// calculate our peer id
string peerIdString = "-TN" + string.Format("{0:00}", Config.MajorVersionNumber)
+ string.Format("{0:00}", Config.MinorVersionNumber) + "-";
ByteField20 peerId = new ByteField20();
System.Array.Copy(System.Text.ASCIIEncoding.ASCII.GetBytes(peerIdString), 0, peerId.Data, 0, peerIdString.Length);
const string peerChars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
System.Random rand = new System.Random();
for (int i = peerIdString.Length; i < 20; ++i)
{
peerId.Data[i] = (byte)peerChars[rand.Next(0, peerChars.Length - 1)];
}
return(peerId);
}
public static void ReceiveHandshake(IO.Stream stream, ref ByteField20 infoDigest)
{
// read in protocol string
byte[] protocolVersionLength = new byte[1];
if ( stream.Read( protocolVersionLength, 0, protocolVersionLength.Length ) != protocolVersionLength.Length )
throw new System.Exception( "Invalid handshake protocol" );
if ( protocolVersionLength[0] != 19 )
throw new System.Exception( "Invalid handshake protocol" );
byte[] protocolBytes = new byte[ protocolVersionLength[ 0 ] ];
if ( stream.Read( protocolBytes, 0, protocolBytes.Length ) != protocolBytes.Length )
throw new System.Exception( "Invalid handshake protocol" );
string protocol = System.Text.ASCIIEncoding.ASCII.GetString(protocolBytes, 0, protocolBytes.Length);
if (protocol != protocolString)
throw new System.Exception( "Invalid handshake protocol" );
// 8 zeros
byte[] zeroes = new byte[ 8 ];
if ( stream.Read( zeroes, 0, zeroes.Length ) != zeroes.Length )
throw new System.Exception( "Invalid handshake protocol" );
// SHA digest
stream.Read(infoDigest.Data, 0, infoDigest.Data.Length);
}
/// <summary>
/// Parses the response from the tracker, and updates the peer list
/// </summary>
/// <param name="stream">IO stream from response</param>
private void ParseTrackerResponse(IO.Stream stream)
{
this.peerList.Clear();
/*
* // because the response stream does not support seeking, we copy the contents to a memorystream
* // to send to the bencoder. This shouldnt cause too much of a performance penalty as it shouldnt
* // be too large anyway.
* byte[] data = new byte[ 1024 ];
* IO.MemoryStream responseStream = new IO.MemoryStream();
* int dataRead = 0;
*
* while ((dataRead = stream.Read(data, 0, data.Length)) > 0)
* {
* responseStream.Write(data, 0, dataRead);
* }
*
* responseStream.Seek(0, IO.SeekOrigin.Begin);
*/
///
BEncode.Dictionary dic = BEncode.NextDictionary(stream);
// note: sometimes IPs can be duplicated in quick disconnection, so there is a check for any duplications
if (dic.Contains("failure reason"))
{
throw new IO.IOException("Tracker connection failed: " + dic.GetString("failure reason"));
}
else
{
this.updateInterval = dic.GetInteger("interval");
BEncode.Element peers = dic["peers"];
if (peers is BEncode.List)
{
// peer list comes as a list of dictionaries
BEncode.List dicList = (BEncode.List)peers;
foreach (BEncode.Dictionary dicPeer in dicList)
{
ByteField20 peerId = new ByteField20(dicPeer.GetBytes("peer id"));
string peerIp = dicPeer.GetString("ip");
int port = dicPeer.GetInteger("port");
PeerInformation peerinfo = new PeerInformation(peerIp, port, peerId);
if (!this.peerList.Contains(peerinfo))
{
this.peerList.Add(peerinfo);
}
}
}
else if (peers is BEncode.String)
{
// else its compressed (this is pretty common)
byte[] compactPeers = ((BEncode.String)peers).Data;
for (int i = 0; i < compactPeers.Length; i += 6)
{
int ip1 = 0xFF & compactPeers[i];
int ip2 = 0xFF & compactPeers[i + 1];
int ip3 = 0xFF & compactPeers[i + 2];
int ip4 = 0xFF & compactPeers[i + 3];
int po1 = 0xFF & compactPeers[i + 4];
int po2 = 0xFF & compactPeers[i + 5];
string peerIp = ip1 + "." + ip2 + "." + ip3 + "." + ip4;
int port = (po1 * 256) + po2;
PeerInformation peerinfo = new PeerInformation(peerIp, port);
if (!this.peerList.Contains(peerinfo))
{
this.peerList.Add(peerinfo);
}
}
}
else
{
throw new TrackerException("Unexcepted error");
}
}
}
/// <summary>
/// This *must* be called before any operations are performed. This should be in the constructor, but as it can be a time-consuming process
/// it was decided against. This analyzes the file to look for which pieces are downloaded, or if the torrent has just started it will create the
/// new, empty files.
/// </summary>
/// <param name="callback">Callback delegate to inform the caller of the progress</param>
public void CheckIntegrity( bool forced, CheckIntegrityCallback callback)
{
// if their already is a piece file in the application directory, load it from there. (unless it is forced where is has to do it)
if ( forced || !GetPieceInfoFromFile(callback))
{
int dataPosition = 0, filePosition = 0;
int i = 0;
byte[] data = new byte[this.infofile.GetPieceLength(0)];
Crypto.SHA1 sha = Crypto.SHA1CryptoServiceProvider.Create();
for (int currentFile=0; currentFile<this.infofile.FileCount; ++currentFile)
{
int fileLength = this.infofile.GetFileLength(currentFile);
string path = this.infofile.GetFileName(currentFile);
IO.FileInfo fileInfo = new IO.FileInfo(path);
if (!fileInfo.Exists)
{
// create the file if it does not exist
this.CreateEmptyFile(fileInfo, fileLength);
int fileDataLeft = 0;
if (dataPosition > 0)
{
// if dataPosition does not equal zero, meaning we have some of a piece from the last file. This automatically fails,
// and we move onto the next piece.
i++;
fileDataLeft = fileLength - (this.infofile.GetPieceLength(0) - dataPosition);
}
else
fileDataLeft = fileLength - filePosition;
int numPieces = fileDataLeft / this.infofile.GetPieceLength(0);
i += numPieces;
if (fileDataLeft % this.infofile.GetPieceLength(0) > 0)
{
// set the next file's filePosition, and fail the next piece
filePosition = this.infofile.GetPieceLength(i) - (fileDataLeft % this.infofile.GetPieceLength(i));
i++;
}
else
{
filePosition = 0;
}
dataPosition = 0;
if (callback != null)
callback(this, i, false, ((float)(i+1)/(float)this.infofile.PieceCount) * 100.0f);
// move onto next file
continue;
}
else
{
// check the length, otherwise truncate it
if (fileInfo.Length != fileLength)
this.TruncateFile(fileInfo, fileLength);
// open the file, start checking.
IO.FileStream fstream = fileInfo.OpenRead();
while (filePosition < fileLength)
{
int dataToRead = System.Math.Min(fileLength - filePosition, this.infofile.GetPieceLength(i) - dataPosition);
byte[] tempData = new byte[dataToRead];
fstream.Read(tempData, 0, tempData.Length);
if (dataToRead + dataPosition >= this.infofile.GetPieceLength(i))
{
// piece finished
System.Array.Copy(tempData, 0, data, dataPosition, dataToRead);
sha.ComputeHash(data, 0, this.infofile.GetPieceLength(i));
ByteField20 final = new ByteField20(sha.Hash);
bool good = final.Equals( this.infofile.GetSHADigest(i) );
if (!good) // if piece is good we can subtract it from the bytes left to download
numBytesLeft += this.infofile.GetPieceLength(i);
this.piecesDownloaded.Set(i, good);
if (callback != null)
callback(this, i, good, ((float)(i+1)/(float)this.infofile.PieceCount) * 100.0f);
i++;
dataPosition = 0;
}
else
{
System.Array.Copy(tempData, 0, data, dataPosition, dataToRead);
dataPosition += dataToRead;
}
filePosition += dataToRead;
}
filePosition = 0;
fstream.Close();
}
}
}
if (this.PercentChanged != null)
this.PercentChanged(this, this.PercentComplete);
}
private void OnAccept(System.IAsyncResult result)
{
Sockets.Socket socket;
try
{
// Accept connections from other peers, find the appropriate torrent and add the peer to it
socket = this.mListener.EndAccept(result);
}
catch (System.Exception)
{
if (this.mListener != null)
{
this.mListener.Close();
}
this.mListener = null;
return;
}
try
{
ByteField20 infoDigest = new ByteField20(), peerId = new ByteField20();
Sockets.NetworkStream netStream = new Sockets.NetworkStream(socket, true);
PeerProtocol.ReceiveHandshake(netStream, ref infoDigest);
Torrent torrent = this.FindTorrent(infoDigest);
if (torrent != null)
{
// found it, finish handshaking and add the peer to the list
PeerProtocol.SendHandshake(netStream, torrent.Metainfo.InfoDigest);
PeerProtocol.SendPeerId(netStream, mLocalPeerId);
if (!PeerProtocol.ReceivePeerId(netStream, ref peerId))
{ // NAT check, discard
socket.Close();
}
else
{
if (!peerId.Equals(mLocalPeerId)) // make sure we aren't connecting to ourselves
{
Net.IPEndPoint endPoint = (Net.IPEndPoint)socket.RemoteEndPoint;
PeerInformation peerInformation = new PeerInformation(endPoint.Address.ToString(), endPoint.Port, peerId);
// add the peer to the torrent
torrent.AddPeer(socket, netStream, peerInformation);
}
else
{
socket.Close();
}
}
}
else
{
socket.Close();
}
}
catch (System.Exception e)
{
Config.LogException(e);
socket.Close();
}
this.mListener.BeginAccept(new System.AsyncCallback(OnAccept), null);
}
/// <summary>
/// This *must* be called before any operations are performed. This should be in the constructor, but as it can be a time-consuming process
/// it was decided against. This analyzes the file to look for which pieces are downloaded, or if the torrent has just started it will create the
/// new, empty files.
/// </summary>
/// <param name="callback">Callback delegate to inform the caller of the progress</param>
public void CheckIntegrity(bool forced, CheckIntegrityCallback callback)
{
// if their already is a piece file in the application directory, load it from there. (unless it is forced where is has to do it)
if (forced || !GetPieceInfoFromFile(callback))
{
int dataPosition = 0, filePosition = 0;
int i = 0;
byte[] data = new byte[this.infofile.GetPieceLength(0)];
Crypto.SHA1 sha = Crypto.SHA1CryptoServiceProvider.Create();
for (int currentFile = 0; currentFile < this.infofile.FileCount; ++currentFile)
{
int fileLength = this.infofile.GetFileLength(currentFile);
string path = this.infofile.GetFileName(currentFile);
IO.FileInfo fileInfo = new IO.FileInfo(path);
if (!fileInfo.Exists)
{
// create the file if it does not exist
this.CreateEmptyFile(fileInfo, fileLength);
int fileDataLeft = 0;
if (dataPosition > 0)
{
// if dataPosition does not equal zero, meaning we have some of a piece from the last file. This automatically fails,
// and we move onto the next piece.
i++;
fileDataLeft = fileLength - (this.infofile.GetPieceLength(0) - dataPosition);
}
else
{
fileDataLeft = fileLength - filePosition;
}
int numPieces = fileDataLeft / this.infofile.GetPieceLength(0);
i += numPieces;
if (fileDataLeft % this.infofile.GetPieceLength(0) > 0)
{
// set the next file's filePosition, and fail the next piece
filePosition = this.infofile.GetPieceLength(i) - (fileDataLeft % this.infofile.GetPieceLength(i));
i++;
}
else
{
filePosition = 0;
}
dataPosition = 0;
if (callback != null)
{
callback(this, i, false, ((float)(i + 1) / (float)this.infofile.PieceCount) * 100.0f);
}
// move onto next file
continue;
}
else
{
// check the length, otherwise truncate it
if (fileInfo.Length != fileLength)
{
this.TruncateFile(fileInfo, fileLength);
}
// open the file, start checking.
IO.FileStream fstream = fileInfo.OpenRead();
while (filePosition < fileLength)
{
int dataToRead = System.Math.Min(fileLength - filePosition, this.infofile.GetPieceLength(i) - dataPosition);
byte[] tempData = new byte[dataToRead];
fstream.Read(tempData, 0, tempData.Length);
if (dataToRead + dataPosition >= this.infofile.GetPieceLength(i))
{
// piece finished
System.Array.Copy(tempData, 0, data, dataPosition, dataToRead);
sha.ComputeHash(data, 0, this.infofile.GetPieceLength(i));
ByteField20 final = new ByteField20(sha.Hash);
bool good = final.Equals(this.infofile.GetSHADigest(i));
if (!good) // if piece is good we can subtract it from the bytes left to download
{
numBytesLeft += this.infofile.GetPieceLength(i);
}
this.piecesDownloaded.Set(i, good);
if (callback != null)
{
callback(this, i, good, ((float)(i + 1) / (float)this.infofile.PieceCount) * 100.0f);
}
i++;
dataPosition = 0;
}
else
{
System.Array.Copy(tempData, 0, data, dataPosition, dataToRead);
dataPosition += dataToRead;
}
filePosition += dataToRead;
}
filePosition = 0;
fstream.Close();
}
}
}
if (this.PercentChanged != null)
{
this.PercentChanged(this, this.PercentComplete);
}
}
public static bool ReceivePeerId(IO.Stream stream, ref ByteField20 peerId)
{
return(stream.Read(peerId.Data, 0, peerId.Data.Length) > 0);
}
/// <summary>Constructs a MetainfoFile</summary>
/// <param name="istream">Stream to read data from</param>
public MetainfoFile(IO.Stream istream)
{
BEncode.Dictionary mainDictionary = (BEncode.Dictionary)BEncode.NextElement(istream);
this.announceUrl = mainDictionary.GetString(new BEncode.String("announce"));
if (mainDictionary.Contains("comment"))
{
this.comment = mainDictionary.GetString("comment");
}
if (mainDictionary.Contains("created by"))
{
this.createdBy = mainDictionary.GetString("created by");
}
if (mainDictionary.Contains("creation date"))
{
int creation = mainDictionary.GetInteger("creation date");
this.creationDate = new System.DateTime(1970, 1, 1, 0, 0, 0);
this.creationDate = this.creationDate.AddSeconds(creation);
}
BEncode.Dictionary infoDictionary = mainDictionary.GetDictionary("info");
this.name = infoDictionary.GetString("name");
this.pieceLength = infoDictionary.GetInteger("piece length");
this.pieceFileName = this.name.ToLower().Replace(' ', '_');
// Get SHA digests
byte[] pieces = infoDictionary.GetBytes("pieces");
int numPieces = pieces.Length / 20;
this.shaDigestList.Capacity = numPieces;
for (int i = 0; i < numPieces; ++i)
{
this.shaDigestList.Add(new ByteField20(pieces, i * 20));
}
// Get filenames and lengths
if (infoDictionary.Contains("length"))
{
// one file
this.fileList.Add(name);
int fileLength = infoDictionary.GetInteger("length");
this.fileLengthList.Add(fileLength);
this.totalSize = fileLength;
}
else
{
// multiple files - a list of dictionaries containing the filename and length
BEncode.List files = infoDictionary.GetList("files");
this.fileList.Capacity = this.fileLengthList.Capacity = files.Count;
this.totalSize = 0;
foreach (BEncode.Dictionary fileDic in files)
{
BEncode.List pathList = fileDic.GetList("path");
string path = this.name + IO.Path.DirectorySeparatorChar;
for (int i = 0; i < pathList.Count - 1; ++i)
{
path += pathList[i].ToString() + IO.Path.DirectorySeparatorChar;
}
path += pathList[pathList.Count - 1];
this.fileList.Add(path);
int fileLength = fileDic.GetInteger("length");
this.fileLengthList.Add(fileLength);
this.totalSize += fileLength;
}
}
// calculate the SHA-1 digest of the info dictionary - this is required for the tracker protocol
istream.Seek(infoDictionary.Position, IO.SeekOrigin.Begin);
byte[] infoData = new byte[infoDictionary.Length];
istream.Read(infoData, 0, infoData.Length);
this.infoDigest = ByteField20.ComputeSHAHash(infoData);
}
public static void SendPeerId(IO.Stream netStream, ByteField20 peerId)
{
netStream.Write(peerId.Data, 0, peerId.Data.Length);
}
private void OnAccept(System.IAsyncResult result)
{
Sockets.Socket socket;
try
{
// Accept connections from other peers, find the appropriate torrent and add the peer to it
socket = this.mListener.EndAccept(result);
}
catch (System.Exception)
{
if (this.mListener != null)
this.mListener.Close();
this.mListener = null;
return;
}
try
{
ByteField20 infoDigest = new ByteField20(), peerId = new ByteField20();
Sockets.NetworkStream netStream = new Sockets.NetworkStream(socket, true);
PeerProtocol.ReceiveHandshake(netStream, ref infoDigest);
Torrent torrent = this.FindTorrent(infoDigest);
if (torrent != null)
{
// found it, finish handshaking and add the peer to the list
PeerProtocol.SendHandshake(netStream, torrent.Metainfo.InfoDigest);
PeerProtocol.SendPeerId(netStream, mLocalPeerId );
if ( !PeerProtocol.ReceivePeerId( netStream, ref peerId ))
{ // NAT check, discard
socket.Close();
}
else
{
if ( !peerId.Equals( mLocalPeerId ) ) // make sure we aren't connecting to ourselves
{
Net.IPEndPoint endPoint = (Net.IPEndPoint)socket.RemoteEndPoint;
PeerInformation peerInformation = new PeerInformation( endPoint.Address.ToString(), endPoint.Port, peerId );
// add the peer to the torrent
torrent.AddPeer( socket, netStream, peerInformation );
}
else
socket.Close();
}
}
else
socket.Close();
}
catch (System.Exception e)
{
Config.LogException( e );
socket.Close();
}
this.mListener.BeginAccept(new System.AsyncCallback(OnAccept), null);
}
private static ByteField20 DefaultCalculatePeerId()
{
// calculate our peer id
string peerIdString = "-TN" + string.Format("{0:00}", Config.MajorVersionNumber)
+ string.Format("{0:00}", Config.MinorVersionNumber) + "-";
ByteField20 peerId = new ByteField20();
System.Array.Copy(System.Text.ASCIIEncoding.ASCII.GetBytes(peerIdString), 0, peerId.Data, 0, peerIdString.Length);
const string peerChars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
System.Random rand = new System.Random();
for (int i=peerIdString.Length; i<20; ++i)
{
peerId.Data[i] = (byte)peerChars[rand.Next(0, peerChars.Length-1)];
}
return peerId;
}
public Session( ByteField20 localPeerId )
{
mLocalPeerId = localPeerId;
if ( Config.ActiveConfig.ProxyURL != "" ) // set web proxy
{
System.Net.WebRequest.DefaultWebProxy = new Net.WebProxy( Config.ActiveConfig.ProxyURL );
}
SetAllowUnsafeHeaderParsing20();
this.StartServer();
}
public Torrent FindTorrent(ByteField20 infoDigest)
{
lock ( this.mTorrents )
{
foreach ( Torrent torrent in this.mTorrents )
{
if (torrent.Metainfo.InfoDigest.Equals(infoDigest))
{
return torrent;
}
}
return null;
}
}
/// <summary>Constructs a MetainfoFile</summary>
/// <param name="istream">Stream to read data from</param>
public MetainfoFile(IO.Stream istream)
{
BEncode.Dictionary mainDictionary = (BEncode.Dictionary)BEncode.NextElement(istream);
this.announceUrl = mainDictionary.GetString(new BEncode.String("announce"));
if (mainDictionary.Contains("comment"))
this.comment = mainDictionary.GetString("comment");
if (mainDictionary.Contains("created by"))
this.createdBy = mainDictionary.GetString("created by");
if (mainDictionary.Contains("creation date"))
{
int creation = mainDictionary.GetInteger("creation date");
this.creationDate = new System.DateTime(1970, 1, 1, 0, 0, 0);
this.creationDate = this.creationDate.AddSeconds(creation);
}
BEncode.Dictionary infoDictionary = mainDictionary.GetDictionary("info");
this.name = infoDictionary.GetString("name");
this.pieceLength = infoDictionary.GetInteger("piece length");
this.pieceFileName = this.name.ToLower().Replace(' ', '_');
// Get SHA digests
byte[] pieces = infoDictionary.GetBytes("pieces");
int numPieces = pieces.Length / 20;
this.shaDigestList.Capacity = numPieces;
for (int i=0; i<numPieces; ++i)
{
this.shaDigestList.Add( new ByteField20(pieces, i*20) );
}
// Get filenames and lengths
if (infoDictionary.Contains("length"))
{
// one file
this.fileList.Add(name);
int fileLength = infoDictionary.GetInteger("length");
this.fileLengthList.Add(fileLength);
this.totalSize = fileLength;
}
else
{
// multiple files - a list of dictionaries containing the filename and length
BEncode.List files = infoDictionary.GetList("files");
this.fileList.Capacity = this.fileLengthList.Capacity = files.Count;
this.totalSize = 0;
foreach (BEncode.Dictionary fileDic in files)
{
BEncode.List pathList = fileDic.GetList("path");
string path = this.name + IO.Path.DirectorySeparatorChar;
for (int i=0; i<pathList.Count-1; ++i)
{
path += pathList[i].ToString() + IO.Path.DirectorySeparatorChar;
}
path += pathList[ pathList.Count-1 ];
this.fileList.Add(path);
int fileLength = fileDic.GetInteger("length");
this.fileLengthList.Add(fileLength);
this.totalSize += fileLength;
}
}
// calculate the SHA-1 digest of the info dictionary - this is required for the tracker protocol
istream.Seek(infoDictionary.Position, IO.SeekOrigin.Begin);
byte[] infoData = new byte[ infoDictionary.Length ];
istream.Read(infoData, 0, infoData.Length);
this.infoDigest = ByteField20.ComputeSHAHash(infoData);
}
/// <summary>
/// Parses the response from the tracker, and updates the peer list
/// </summary>
/// <param name="stream">IO stream from response</param>
private void ParseTrackerResponse(IO.Stream stream)
{
this.peerList.Clear();
/*
// because the response stream does not support seeking, we copy the contents to a memorystream
// to send to the bencoder. This shouldnt cause too much of a performance penalty as it shouldnt
// be too large anyway.
byte[] data = new byte[ 1024 ];
IO.MemoryStream responseStream = new IO.MemoryStream();
int dataRead = 0;
while ((dataRead = stream.Read(data, 0, data.Length)) > 0)
{
responseStream.Write(data, 0, dataRead);
}
responseStream.Seek(0, IO.SeekOrigin.Begin);
*/
///
BEncode.Dictionary dic = BEncode.NextDictionary(stream);
// note: sometimes IPs can be duplicated in quick disconnection, so there is a check for any duplications
if (dic.Contains("failure reason"))
{
throw new IO.IOException("Tracker connection failed: " + dic.GetString("failure reason"));
}
else
{
this.updateInterval = dic.GetInteger("interval");
BEncode.Element peers = dic["peers"];
if (peers is BEncode.List)
{
// peer list comes as a list of dictionaries
BEncode.List dicList = (BEncode.List)peers;
foreach (BEncode.Dictionary dicPeer in dicList)
{
ByteField20 peerId = new ByteField20(dicPeer.GetBytes("peer id"));
string peerIp = dicPeer.GetString("ip");
int port = dicPeer.GetInteger("port");
PeerInformation peerinfo = new PeerInformation(peerIp, port, peerId);
if (!this.peerList.Contains(peerinfo))
this.peerList.Add(peerinfo);
}
}
else if (peers is BEncode.String)
{
// else its compressed (this is pretty common)
byte[] compactPeers = ((BEncode.String)peers).Data;
for (int i=0; i<compactPeers.Length; i += 6)
{
int ip1 = 0xFF & compactPeers[i];
int ip2 = 0xFF & compactPeers[i+1];
int ip3 = 0xFF & compactPeers[i+2];
int ip4 = 0xFF & compactPeers[i+3];
int po1 = 0xFF & compactPeers[i+4];
int po2 = 0xFF & compactPeers[i+5];
string peerIp = ip1 + "." + ip2 + "." + ip3 + "." + ip4;
int port = (po1 * 256) + po2;
PeerInformation peerinfo = new PeerInformation(peerIp, port);
if (!this.peerList.Contains(peerinfo))
this.peerList.Add(peerinfo);
}
}
else
throw new TrackerException("Unexcepted error");
}
}
public static void SendPeerId(IO.Stream netStream, ByteField20 peerId)
{
netStream.Write(peerId.Data, 0, peerId.Data.Length);
}
/// <summary>
/// Helper thread method to start the connection to peers
/// </summary>
/// <param name="state"></param>
private void StartPeerConnectionThread(System.IAsyncResult result)
{
object[] objs = (object[])result.AsyncState;
Sockets.Socket socket = (Sockets.Socket)objs[0];
PeerInformation peerinfo = (PeerInformation)objs[1];
ByteField20 infoDigest = new ByteField20(), peerId = new ByteField20();
Sockets.NetworkStream netStream;
try
{
socket.EndConnect(result);
netStream = new Sockets.NetworkStream(socket, true);
// send handshake info
PeerProtocol.SendHandshake(netStream, this.infofile.InfoDigest);
PeerProtocol.ReceiveHandshake(netStream, ref infoDigest);
PeerProtocol.SendPeerId(netStream, this.mSession.LocalPeerID );
if (!PeerProtocol.ReceivePeerId(netStream, ref peerId))
{ // NAT check
socket.Close();
return;
}
// check info digest matches and we are not attempting to connect to ourself
if ( infoDigest.Equals( this.infofile.InfoDigest ) && !peerId.Equals( this.mSession.LocalPeerID ) )
{
peerinfo.ID = peerId;
this.AddPeer(socket, netStream, peerinfo);
}
else // info digest doesn't match, close the connection
socket.Close();
}
catch (System.Exception e)
{
Config.LogException(e);
// die if the connection failed
if (socket != null)
socket.Close();
return;
}
}
public static bool ReceivePeerId(IO.Stream stream, ref ByteField20 peerId)
{
return stream.Read(peerId.Data, 0, peerId.Data.Length) > 0;
}
