//synchronous reception
internal DataFragment ReceivePacket() {
while(true) {
DataFragment data = _packetReceiver.WaitResponse();
PacketType pt = (PacketType)data.ByteAt(0); //sneak
//filter unnecessary packet
if(pt==PacketType.SSH_MSG_IGNORE) {
SSH2DataReader r = new SSH2DataReader(data);
r.ReadPacketType(); //skip
byte[] msg = r.ReadString();
if(_eventReceiver!=null) _eventReceiver.OnIgnoreMessage(msg);
TraceReceptionEvent(pt, msg);
}
else if(pt==PacketType.SSH_MSG_DEBUG) {
SSH2DataReader r = new SSH2DataReader(data);
r.ReadPacketType(); //skip
bool f = r.ReadBool();
byte[] msg = r.ReadString();
if(_eventReceiver!=null) _eventReceiver.OnDebugMessage(f, msg);
TraceReceptionEvent(pt, msg);
}
else {
return data;
}
}
}
private void ProcessChannelLocalData(ISSHChannelEventReceiver receiver, PacketType pt, SSH2DataReader re) {
switch(pt) {
case PacketType.SSH_MSG_CHANNEL_DATA: {
int len = re.ReadInt32();
receiver.OnData(re.Image, re.Offset, len);
}
break;
case PacketType.SSH_MSG_CHANNEL_EXTENDED_DATA: {
int t = re.ReadInt32();
byte[] data = re.ReadString();
receiver.OnExtendedData(t, data);
}
break;
case PacketType.SSH_MSG_CHANNEL_REQUEST: {
string request = Encoding.ASCII.GetString(re.ReadString());
bool reply = re.ReadBool();
if(request=="exit-status") {
int status = re.ReadInt32();
}
else if(reply) { //we reject unknown requests including keep-alive check
SSH2DataWriter wr = new SSH2DataWriter();
wr.WritePacketType(PacketType.SSH_MSG_CHANNEL_FAILURE);
wr.Write(_remoteID);
TransmitPayload(wr.ToByteArray());
}
}
break;
case PacketType.SSH_MSG_CHANNEL_EOF:
receiver.OnChannelEOF();
break;
case PacketType.SSH_MSG_CHANNEL_CLOSE:
_connection.ChannelCollection.UnregisterChannelEventReceiver(_localID);
receiver.OnChannelClosed();
break;
case PacketType.SSH_MSG_CHANNEL_FAILURE:
receiver.OnMiscPacket((byte)pt, re.Image, re.Offset, re.Rest);
break;
default:
receiver.OnMiscPacket((byte)pt, re.Image, re.Offset, re.Rest);
Debug.WriteLine("Unknown Packet "+pt);
break;
}
}
private AuthenticationResult ProcessAuthenticationResponse() {
do {
SSH2DataReader response = new SSH2DataReader(ReceivePacket());
PacketType h = response.ReadPacketType();
if(h==PacketType.SSH_MSG_USERAUTH_FAILURE) {
string msg = Encoding.ASCII.GetString(response.ReadString());
TraceReceptionEvent(h, "user authentication failed:" + msg);
return AuthenticationResult.Failure;
}
else if(h==PacketType.SSH_MSG_USERAUTH_BANNER) {
TraceReceptionEvent(h, "");
}
else if(h==PacketType.SSH_MSG_USERAUTH_SUCCESS) {
TraceReceptionEvent(h, "user authentication succeeded");
_packetBuilder.InnerHandler = new CallbackSSH2PacketHandler(this);
return AuthenticationResult.Success; //successfully exit
}
else if(h==PacketType.SSH_MSG_USERAUTH_INFO_REQUEST) {
string name = Encoding.ASCII.GetString(response.ReadString());
string inst = Encoding.ASCII.GetString(response.ReadString());
string lang = Encoding.ASCII.GetString(response.ReadString());
int num = response.ReadInt32();
string[] prompts = new string[num];
for(int i=0; i<num; i++) {
prompts[i] = Encoding.ASCII.GetString(response.ReadString());
bool echo = response.ReadBool();
}
_eventReceiver.OnAuthenticationPrompt(prompts);
_requiredResponseCount = num;
return AuthenticationResult.Prompt;
}
else
throw new SSHException("protocol error: unexpected packet type "+h);
} while(true);
}
private void ProcessKEXINIT(DataFragment packet) {
SSH2DataReader re = null;
do {
_serverKEXINITPayload = packet.ToNewArray();
re = new SSH2DataReader(_serverKEXINITPayload);
byte[] head = re.Read(17); //Type and cookie
PacketType pt = (PacketType)head[0];
if(pt==PacketType.SSH_MSG_KEXINIT)
break; //successfully exit
else if(pt==PacketType.SSH_MSG_IGNORE || pt==PacketType.SSH_MSG_DEBUG) { //continue
packet = _connection.ReceivePacket();
}
else
throw new SSHException(String.Format("Server response is not SSH_MSG_KEXINIT but {0}", head[0]));
} while(true);
Encoding enc = Encoding.ASCII;
string kex = enc.GetString(re.ReadString());
_cInfo._supportedKEXAlgorithms = kex;
CheckAlgorithmSupport("keyexchange", kex, "diffie-hellman-group1-sha1");
string host_key = enc.GetString(re.ReadString());
_cInfo._supportedHostKeyAlgorithms = host_key;
_cInfo._algorithmForHostKeyVerification = DecideHostKeyAlgorithm(host_key);
string enc_cs = enc.GetString(re.ReadString());
_cInfo._supportedCipherAlgorithms = enc_cs;
_cInfo._algorithmForTransmittion = DecideCipherAlgorithm(enc_cs);
string enc_sc = enc.GetString(re.ReadString());
_cInfo._algorithmForReception = DecideCipherAlgorithm(enc_sc);
string mac_cs = enc.GetString(re.ReadString());
CheckAlgorithmSupport("mac", mac_cs, "hmac-sha1");
string mac_sc = enc.GetString(re.ReadString());
CheckAlgorithmSupport("mac", mac_sc, "hmac-sha1");
string comp_cs = enc.GetString(re.ReadString());
CheckAlgorithmSupport("compression", comp_cs, "none");
string comp_sc = enc.GetString(re.ReadString());
CheckAlgorithmSupport("compression", comp_sc, "none");
string lang_cs = enc.GetString(re.ReadString());
string lang_sc = enc.GetString(re.ReadString());
bool flag = re.ReadBool();
int reserved = re.ReadInt32();
Debug.Assert(re.Rest==0);
if(_connection.IsEventTracerAvailable) {
StringBuilder bld = new StringBuilder();
bld.Append("kex_algorithm="); bld.Append(kex);
bld.Append("; server_host_key_algorithms="); bld.Append(host_key);
bld.Append("; encryption_algorithms_client_to_server="); bld.Append(enc_cs);
bld.Append("; encryption_algorithms_server_to_client="); bld.Append(enc_sc);
bld.Append("; mac_algorithms_client_to_server="); bld.Append(mac_cs);
bld.Append("; mac_algorithms_server_to_client="); bld.Append(mac_sc);
bld.Append("; comression_algorithms_client_to_server="); bld.Append(comp_cs);
bld.Append("; comression_algorithms_server_to_client="); bld.Append(comp_sc);
TraceReceptionNegotiation(PacketType.SSH_MSG_KEXINIT, bld.ToString());
}
if(flag) throw new SSHException("Algorithm negotiation failed");
}
/// <summary>
/// Process packet about this channel.
/// </summary>
/// <param name="packetType">a packet type (message number)</param>
/// <param name="packetFragment">a packet image except message number and recipient channel.</param>
public void ProcessPacket(SSH2PacketType packetType, DataFragment packetFragment)
{
if (_state == State.Closed) {
return; // ignore
}
DataFragment dataFragmentArg;
uint dataTypeCodeArg;
lock (_stateSync) {
switch (_state) {
case State.InitiatedByServer:
break;
case State.InitiatedByClient:
if (packetType == SSH2PacketType.SSH_MSG_CHANNEL_OPEN_CONFIRMATION) {
SSH2DataReader reader = new SSH2DataReader(packetFragment);
RemoteChannel = reader.ReadUInt32();
_serverWindowSizeLeft = reader.ReadUInt32();
_serverMaxPacketSize = reader.ReadUInt32();
_state = State.Established;
Monitor.PulseAll(_stateSync); // notifies state change
dataFragmentArg = reader.GetRemainingDataView();
goto OnEstablished; // do it out of the lock block
}
if (packetType == SSH2PacketType.SSH_MSG_CHANNEL_OPEN_FAILURE) {
SSH2DataReader reader = new SSH2DataReader(packetFragment);
uint reasonCode = reader.ReadUInt32();
string description = reader.ReadUTF8String();
string lang = reader.ReadString();
goto RequestFailed; // do it out of the lock block
}
break;
case State.Closing:
if (packetType == SSH2PacketType.SSH_MSG_CHANNEL_CLOSE) {
goto SetStateClosedByClient; // do it out of the lock block
}
break;
case State.Established:
case State.Ready:
if (ProcessPacketSub(packetType, packetFragment) == SubPacketProcessResult.Consumed) {
return;
}
switch (packetType) {
case SSH2PacketType.SSH_MSG_CHANNEL_DATA: {
SSH2DataReader reader = new SSH2DataReader(packetFragment);
int len = reader.ReadInt32();
dataFragmentArg = reader.GetRemainingDataView(len);
AdjustWindowSize(len);
}
goto OnData; // do it out of the lock block
case SSH2PacketType.SSH_MSG_CHANNEL_EXTENDED_DATA: {
SSH2DataReader reader = new SSH2DataReader(packetFragment);
dataTypeCodeArg = reader.ReadUInt32();
int len = reader.ReadInt32();
dataFragmentArg = reader.GetRemainingDataView(len);
AdjustWindowSize(len);
}
goto OnExtendedData; // do it out of the lock block
case SSH2PacketType.SSH_MSG_CHANNEL_REQUEST: {
SSH2DataReader reader = new SSH2DataReader(packetFragment);
string request = reader.ReadString();
bool wantReply = reader.ReadBool();
if (wantReply) { //we reject unknown requests including keep-alive check
Transmit(
0,
new SSH2Packet(SSH2PacketType.SSH_MSG_CHANNEL_FAILURE)
.WriteUInt32(RemoteChannel)
);
}
}
break;
case SSH2PacketType.SSH_MSG_CHANNEL_EOF:
goto OnEOF; // do it out of the lock block
case SSH2PacketType.SSH_MSG_CHANNEL_CLOSE:
Transmit(
0,
new SSH2Packet(SSH2PacketType.SSH_MSG_CHANNEL_CLOSE)
.WriteUInt32(RemoteChannel)
);
goto SetStateClosedByServer; // do it out of the lock block
case SSH2PacketType.SSH_MSG_CHANNEL_WINDOW_ADJUST: {
SSH2DataReader reader = new SSH2DataReader(packetFragment);
uint bytesToAdd = reader.ReadUInt32();
// some servers may not send SSH_MSG_CHANNEL_WINDOW_ADJUST.
// it is dangerous to wait this message in send procedure
_serverWindowSizeLeft += bytesToAdd;
}
goto OnWindowAdjust;
case SSH2PacketType.SSH_MSG_CHANNEL_SUCCESS:
case SSH2PacketType.SSH_MSG_CHANNEL_FAILURE: {
_channelRequestResult.TrySet(packetType == SSH2PacketType.SSH_MSG_CHANNEL_SUCCESS, 1000);
}
break;
default:
goto OnUnhandledPacket;
}
break; // case State.Ready
}
}
return;
OnEstablished:
_protocolEventManager.Trace(
"CH[{0}] remoteCH={1} remoteWindowSize={2} remoteMaxPacketSize={3}",
LocalChannel, RemoteChannel, _serverWindowSizeLeft, _serverMaxPacketSize);
_handler.OnEstablished(dataFragmentArg);
OnChannelEstablished();
return;
RequestFailed:
_protocolEventManager.Trace("CH[{0}] request failed", LocalChannel);
RequestFailed();
return;
SetStateClosedByClient:
_protocolEventManager.Trace("CH[{0}] closed completely", LocalChannel);
SetStateClosed(false);
return;
SetStateClosedByServer:
_protocolEventManager.Trace("CH[{0}] closed by server", LocalChannel);
SetStateClosed(true);
return;
OnData:
_handler.OnData(dataFragmentArg);
return;
OnExtendedData:
_handler.OnExtendedData(dataTypeCodeArg, dataFragmentArg);
return;
OnEOF:
_protocolEventManager.Trace("CH[{0}] caught EOF", LocalChannel);
_handler.OnEOF();
return;
OnWindowAdjust:
_protocolEventManager.Trace(
"CH[{0}] adjusted remote window size to {1}",
LocalChannel, _serverWindowSizeLeft);
return;
OnUnhandledPacket:
_handler.OnUnhandledPacket((byte)packetType, packetFragment);
return;
}
private void ProcessChannelLocalData(ISSHChannelEventReceiver receiver, SSH2PacketType pt, SSH2DataReader re)
{
switch (pt) {
case SSH2PacketType.SSH_MSG_CHANNEL_DATA: {
int len = re.ReadInt32();
DataFragment frag = re.GetRemainingDataView(len);
receiver.OnData(frag.Data, frag.Offset, frag.Length);
}
break;
case SSH2PacketType.SSH_MSG_CHANNEL_EXTENDED_DATA: {
int t = re.ReadInt32();
byte[] data = re.ReadByteString();
receiver.OnExtendedData(t, data);
}
break;
case SSH2PacketType.SSH_MSG_CHANNEL_REQUEST: {
string request = re.ReadString();
bool reply = re.ReadBool();
if (request == "exit-status") {
int status = re.ReadInt32();
}
else if (reply) { //we reject unknown requests including keep-alive check
Transmit(
0,
new SSH2Packet(SSH2PacketType.SSH_MSG_CHANNEL_FAILURE)
.WriteInt32(_remoteID)
);
}
}
break;
case SSH2PacketType.SSH_MSG_CHANNEL_EOF:
receiver.OnChannelEOF();
break;
case SSH2PacketType.SSH_MSG_CHANNEL_CLOSE:
_connection.ChannelCollection.UnregisterChannelEventReceiver(_localID);
receiver.OnChannelClosed();
break;
case SSH2PacketType.SSH_MSG_CHANNEL_FAILURE: {
DataFragment frag = re.GetRemainingDataView();
receiver.OnMiscPacket((byte)pt, frag.Data, frag.Offset, frag.Length);
}
break;
default: {
DataFragment frag = re.GetRemainingDataView();
receiver.OnMiscPacket((byte)pt, frag.Data, frag.Offset, frag.Length);
}
Debug.WriteLine("Unknown Packet " + pt);
break;
}
}
private void ProcessKEXINIT(DataFragment packet)
{
SSH2DataReader re = null;
do {
_serverKEXINITPayload = packet.GetBytes();
re = new SSH2DataReader(_serverKEXINITPayload);
byte[] head = re.Read(17); //Type and cookie
SSH2PacketType pt = (SSH2PacketType)head[0];
if (pt == SSH2PacketType.SSH_MSG_KEXINIT)
break; //successfully exit
if (pt == SSH2PacketType.SSH_MSG_IGNORE || pt == SSH2PacketType.SSH_MSG_DEBUG) { //continue
packet = _connection.ReceivePacket();
}
else {
throw new SSHException(String.Format("Server response is not SSH_MSG_KEXINIT but {0}", head[0]));
}
} while (true);
string kex = re.ReadString();
_cInfo.SupportedKEXAlgorithms = kex;
_cInfo.KEXAlgorithm = DecideKexAlgorithm(kex);
string host_key = re.ReadString();
_cInfo.SupportedHostKeyAlgorithms = host_key;
_cInfo.HostKeyAlgorithm = DecideHostKeyAlgorithm(host_key);
string enc_cs = re.ReadString();
_cInfo.SupportedEncryptionAlgorithmsClientToServer = enc_cs;
_cInfo.OutgoingPacketCipher = DecideCipherAlgorithm(enc_cs);
string enc_sc = re.ReadString();
_cInfo.SupportedEncryptionAlgorithmsServerToClient = enc_sc;
_cInfo.IncomingPacketCipher = DecideCipherAlgorithm(enc_sc);
string mac_cs = re.ReadString();
CheckAlgorithmSupport("mac", mac_cs, "hmac-sha1");
string mac_sc = re.ReadString();
CheckAlgorithmSupport("mac", mac_sc, "hmac-sha1");
string comp_cs = re.ReadString();
CheckAlgorithmSupport("compression", comp_cs, "none");
string comp_sc = re.ReadString();
CheckAlgorithmSupport("compression", comp_sc, "none");
string lang_cs = re.ReadString();
string lang_sc = re.ReadString();
bool flag = re.ReadBool();
int reserved = re.ReadInt32();
Debug.Assert(re.RemainingDataLength == 0);
if (_connection.IsEventTracerAvailable) {
StringBuilder bld = new StringBuilder();
bld.Append("kex_algorithm=");
bld.Append(kex);
bld.Append("; server_host_key_algorithms=");
bld.Append(host_key);
bld.Append("; encryption_algorithms_client_to_server=");
bld.Append(enc_cs);
bld.Append("; encryption_algorithms_server_to_client=");
bld.Append(enc_sc);
bld.Append("; mac_algorithms_client_to_server=");
bld.Append(mac_cs);
bld.Append("; mac_algorithms_server_to_client=");
bld.Append(mac_sc);
bld.Append("; comression_algorithms_client_to_server=");
bld.Append(comp_cs);
bld.Append("; comression_algorithms_server_to_client=");
bld.Append(comp_sc);
TraceReceptionNegotiation(SSH2PacketType.SSH_MSG_KEXINIT, bld.ToString());
}
if (flag)
throw new SSHException("Algorithm negotiation failed");
}
