public void OnPacket(SSH2Packet packet)
{
lock (this) {
_packets.Add(packet);
if (_packets.Count > 0)
{
SetReady();
}
}
}
//returns true if a new packet could be obtained
private SSH2Packet ConstructPacket()
{
SSH2Packet packet = null;
if (_event != null && !_event.WaitOne(3000, false))
{
throw new Exception("waithandle timed out");
}
if (_cipher == null)
{
if (_writeOffset - _readOffset < 4)
{
return(null);
}
int len = SSHUtil.ReadInt32(_buffer, _readOffset);
if (_writeOffset - _readOffset < 4 + len)
{
return(null);
}
packet = SSH2Packet.FromPlainStream(_buffer, _readOffset);
_readOffset += 4 + len;
_sequence++;
}
else
{
if (_head == null)
{
if (_writeOffset - _readOffset < _cipher.BlockSize)
{
return(null);
}
_head = new byte[_cipher.BlockSize];
byte[] eh = new byte[_cipher.BlockSize];
Array.Copy(_buffer, _readOffset, eh, 0, eh.Length);
_readOffset += eh.Length;
_cipher.Decrypt(eh, 0, eh.Length, _head, 0);
}
int len = SSHUtil.ReadInt32(_head, 0);
if (_writeOffset - _readOffset < len + 4 - _head.Length + _mac.Size)
{
return(null);
}
packet = SSH2Packet.FromDecryptedHead(_head, _buffer, _readOffset, _cipher, _sequence++, _mac);
_readOffset += 4 + len - _head.Length + _mac.Size;
_head = null;
}
return(packet);
}
public static SSH2Packet FromPlainPayload(byte[] payload, int blocksize, Random rnd)
{
SSH2Packet p = new SSH2Packet();
int r = 11 - payload.Length % blocksize;
while (r < 4)
{
r += blocksize;
}
p._padding = new byte[r]; //block size is 8, and padding length is at least 4 bytes
rnd.NextBytes(p._padding);
p._payload = payload;
p._packetLength = 1 + payload.Length + p._padding.Length;
return(p);
}
public static SSH2Packet FromDecryptedHead(byte[] head, byte[] buffer, int offset, Cipher cipher, int sequence, MAC mac)
{
SSH2Packet p = new SSH2Packet();
p._packetLength = SSHUtil.ReadInt32(head, 0);
if (p._packetLength <= 0 || p._packetLength >= MAX_PACKET_LENGTH)
{
throw new SSHException(String.Format("packet size {0} is invalid", p._packetLength));
}
SSH2DataWriter buf = new SSH2DataWriter();
buf.Write(sequence);
buf.Write(head);
if (p._packetLength > (cipher.BlockSize - 4))
{
byte[] tmp = new byte[p._packetLength - (cipher.BlockSize - 4)];
cipher.Decrypt(buffer, offset, tmp.Length, tmp, 0);
offset += tmp.Length;
buf.Write(tmp);
}
byte[] result = buf.ToByteArray();
int padding_len = (int)result[8];
if (padding_len < 4)
{
throw new SSHException("padding length is invalid");
}
byte[] payload = new byte[result.Length - 9 - padding_len];
Array.Copy(result, 9, payload, 0, payload.Length);
p._payload = payload;
if (mac != null)
{
p._mac = mac.Calc(result);
if (SSHUtil.memcmp(p._mac, 0, buffer, offset, mac.Size) != 0)
{
throw new SSHException("MAC Error");
}
}
return(p);
}
public SSH2Packet PopPacket()
{
lock (this) {
if (_packets.Count == 0)
{
return(null);
}
else
{
SSH2Packet p = null;
p = (SSH2Packet)_packets[0];
_packets.RemoveAt(0);
if (_packets.Count == 0)
{
_event.Reset();
}
return(p);
}
}
}
//no decryption, no mac
public static SSH2Packet FromPlainStream(byte[] buffer, int offset)
{
SSH2Packet p = new SSH2Packet();
p._packetLength = SSHUtil.ReadInt32(buffer, offset);
if (p._packetLength <= 0 || p._packetLength >= MAX_PACKET_LENGTH)
{
throw new SSHException(String.Format("packet size {0} is invalid", p._packetLength));
}
offset += 4;
byte pl = buffer[offset++];
if (pl < 4)
{
throw new SSHException(String.Format("padding length {0} is invalid", pl));
}
p._payload = new byte[p._packetLength - 1 - pl];
Array.Copy(buffer, offset, p._payload, 0, p._payload.Length);
return(p);
}
public void OnData(byte[] data, int offset, int length)
{
try {
while (_buffer.Length - _writeOffset < length)
{
ExpandBuffer();
}
Array.Copy(data, offset, _buffer, _writeOffset, length);
_writeOffset += length;
SSH2Packet p = ConstructPacket();
while (p != null)
{
_handler.OnPacket(p);
p = ConstructPacket();
}
ReduceBuffer();
}
catch (Exception ex) {
OnError(ex, ex.Message);
}
}
public void OnPacket(SSH2Packet packet)
{
_connection.AsyncReceivePacket(packet);
}
