/lib/otp.net/Otp/AbstractConnection.cs

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/*``The contents of this file are subject to the Erlang Public License,

* Version 1.1, (the "License"); you may not use this file except in

* compliance with the License. You should have received a copy of the

* Erlang Public License along with this software. If not, it can be

* retrieved via the world wide web at http://www.erlang.org/.

* 

* Software distributed under the License is distributed on an "AS IS"

* basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See

* the License for the specific language governing rights and limitations

* under the License.

* 

* The Initial Developer of the Original Code is Ericsson Utvecklings AB.

* Portions created by Ericsson are Copyright 1999, Ericsson Utvecklings

* AB. All Rights Reserved.''

* 

 * Converted from Java to C# by Vlad Dumitrescu (vlad_Dumitrescu@hotmail.com)

*/

using System;

using System.Diagnostics;



namespace Otp

{



    /*

    * Maintains a connection between a C# process and a remote Erlang,

    * C# or C node. The object maintains connection state and allows

    * data to be sent to and received from the peer.

    *

    * <p> This abstract class provides the neccesary methods to maintain

    * the actual connection and encode the messages and headers in the

    * proper format according to the Erlang distribution protocol.

    * Subclasses can use these methods to provide a more or less

    * transparent communication channel as desired. </p>

    *

    * <p> Note that no receive methods are provided. Subclasses must

    * provide methods for message delivery, and may implement their own

    * receive methods. <p>

    *

    * <p> If an exception occurs in any of the methods in this class, the

    * connection will be closed and must be reopened in order to resume

    * communication with the peer. This will be indicated to the subclass

    * by passing the exception to its delivery() method. </p>

    * 

    * <p> The System property OtpConnection.trace can be used to change

    * the initial trace level setting for all connections. Normally the

    * initial trace level is 0 and connections are not traced unless

    * {@link #setTraceLevel setTraceLevel()} is used to change the

    * setting for a particular connection. OtpConnection.trace can be

    * used to turn on tracing by default for all connections. </p>

    **/

    public abstract class AbstractConnection

    {



        static AbstractConnection()

        {

            random = new System.Random();

        }

        protected internal const int headerLen = 2048; // more than enough

        

        protected internal static readonly byte passThrough = 0x70;

        protected internal static readonly byte version = 0x83;

        

        // MD5 challenge messsage tags

        protected internal const int ChallengeReply = 'r';

        protected internal const int ChallengeAck = 'a';

        protected internal const int ChallengeStatus = 's';



        private bool done = false;



        protected internal bool connected = false; // connection status

        protected internal System.Net.Sockets.TcpClient socket; // communication channel

        protected internal OtpPeer peer; // who are we connected to

        protected internal OtpLocalNode self; // this nodes id

        internal System.String name; // local name of this connection

        protected string auth_cookie;



        protected internal bool cookieOk = false; // already checked the cookie for this connection

        protected internal bool sendCookie = true; // Send cookies in messages?



        protected internal System.Threading.Thread thread;



        // tracelevel constants



        /*

        * <p> Set the trace level for this connection. Normally tracing is

        * off by default unless System property OtpConnection.trace was

        * set. </p>

        *

        * <p> The following levels are valid: 0 turns off tracing

        * completely, 1 shows ordinary send and receive messages, 2 shows

        * control messages such as link and unlink, 3 shows handshaking at

        * connection setup, and 4 shows communication with Epmd. Each level

        * includes the information shown by the lower ones. </p>

        *

        **/

        public static OtpTrace.Type traceLevel = OtpTrace.traceLevel;



        protected internal static System.Random random = null;



        /*

        * Accept an incoming connection from a remote node. Used by {@link

        * OtpSelf#accept() OtpSelf.accept()} to create a connection

        * based on data received when handshaking with the peer node, when

        * the remote node is the connection intitiator.

        *

        * @exception C#.io.IOException if it was not possible to connect to the peer.

        * @exception OtpAuthException if handshake resulted in an authentication error

        */

        protected internal AbstractConnection(OtpLocalNode self, System.Net.Sockets.TcpClient s)

        {

            this.self = self;

            this.peer = new OtpPeer();

            this.socket = s;

            this.auth_cookie = self.cookie();



            this.socket.NoDelay = true;

            // Use keepalive timer

            this.socket.Client.SetSocketOption(

                System.Net.Sockets.SocketOptionLevel.Socket,

                System.Net.Sockets.SocketOptionName.KeepAlive, true);

            // Close socket gracefully

            this.socket.Client.SetSocketOption(

                System.Net.Sockets.SocketOptionLevel.Socket,

                System.Net.Sockets.SocketOptionName.DontLinger, true);



            //this.socket.ReceiveTimeout = 5000;



            if (traceLevel >= OtpTrace.Type.handshakeThreshold)

            {

                OtpTrace.TraceEvent("<- ACCEPT FROM " + 

                    System.Net.IPAddress.Parse(s.Client.RemoteEndPoint.ToString()).ToString() + ":" +

                    (s.Client.RemoteEndPoint as System.Net.IPEndPoint).Port.ToString());

            }

            

            // get his info

            recvName(this.peer);

            

            // now find highest common dist value

            if ((peer._proto != self._proto) || (self._distHigh < peer._distLow) || (self._distLow > peer._distHigh))

            {

                close();

                throw new System.IO.IOException("No common protocol found - cannot accept connection");

            }

            // highest common version: min(peer.distHigh, self.distHigh)

            peer.distChoose = (peer._distHigh > self._distHigh?self._distHigh:peer._distHigh);

            

            doAccept();

            this.name = peer.node();

        }

        

        /*

        * Intiate and open a connection to a remote node.

        *

        * @exception C#.io.IOException if it was not possible to connect to the peer.

        * @exception OtpAuthException if handshake resulted in an authentication error.

        */

        protected internal AbstractConnection(OtpLocalNode self, OtpPeer other)

            : this(self, other, self.cookie())

        {

        }



        /*

        * Intiate and open a connection to a remote node.

        *

        * @exception C#.io.IOException if it was not possible to connect to the peer.

        * @exception OtpAuthException if handshake resulted in an authentication error.

        */

        protected internal AbstractConnection(OtpLocalNode self, OtpPeer other, string cookie)

        {

            this.peer = other;

            this.self = self;

            this.socket = null;

            this.auth_cookie = cookie;

            

            //this.IsBackground = true;

            

            // now get a connection between the two...

            int port = OtpEpmd.lookupPort(peer);

            

            // now find highest common dist value

            if ((peer._proto != self._proto) || (self._distHigh < peer._distLow) || (self._distLow > peer._distHigh))

            {

                throw new System.IO.IOException("No common protocol found - cannot connect");

            }

            

            // highest common version: min(peer.distHigh, self.distHigh)

            peer.distChoose = (peer._distHigh > self._distHigh ? self._distHigh : peer._distHigh);

            

            doConnect(port);

            

            this.name = peer.node();

            this.connected = true;

        }

        

        /*

        * Deliver communication exceptions to the recipient.

        **/

        public abstract void  deliver(System.Exception e);

        

        /*

        * Deliver messages to the recipient.

        **/

        public abstract void  deliver(OtpMsg msg);

        

        /*

        * Send a pre-encoded message to a named process on a remote node.

        *

        * @param dest the name of the remote process.

        * @param payload the encoded message to send.

        *

        * @exception C#.io.IOException if the connection is not active or

        * a communication error occurs.

        **/

        protected internal virtual void  sendBuf(Erlang.Pid from, System.String dest, OtpOutputStream payload)

        {

            if (!connected)

            {

                throw new System.IO.IOException("Not connected");

            }

            OtpOutputStream header = new OtpOutputStream(headerLen);

            

            // preamble: 4 byte length + "passthrough" tag + version

            header.write4BE(0); // reserve space for length

            header.write1(passThrough);

            header.write1(version);

            

            // header info

            header.write_tuple_head(4);

            header.write_long((long)OtpMsg.Tag.regSendTag);

            header.write_any(from);

            if (sendCookie)

                header.write_atom(auth_cookie);

            else

                header.write_atom("");

            header.write_atom(dest);

            

            // version for payload

            header.write1(version);

            

            // fix up length in preamble

            header.poke4BE(0, header.count() + payload.count() - 4);

            

            do_send(header, payload);

        }

        

        /*

        * Send a pre-encoded message to a process on a remote node.

        *

        * @param dest the Erlang PID of the remote process.

        * @param msg the encoded message to send.

        *

        * @exception C#.io.IOException if the connection is not active

        * or a communication error occurs.

        **/

        protected internal virtual void  sendBuf(Erlang.Pid from, Erlang.Pid dest, OtpOutputStream payload)

        {

            if (!connected)

            {

                throw new System.IO.IOException("Not connected");

            }

            OtpOutputStream header = new OtpOutputStream(headerLen);

            

            // preamble: 4 byte length + "passthrough" tag + version

            header.write4BE(0); // reserve space for length

            header.write1(passThrough);

            header.write1(version);

            

            // header info

            header.write_tuple_head(3);

            header.write_long((long)OtpMsg.Tag.sendTag);

            if (sendCookie)

                header.write_atom(auth_cookie);

            else

                header.write_atom("");

            header.write_any(dest);

            

            // version for payload

            header.write1(version);

            

            // fix up length in preamble

            header.poke4BE(0, header.count() + payload.count() - 4);

            

            do_send(header, payload);

        }



        /*Send an auth error to peer because he sent a bad cookie.

        * The auth error uses his cookie (not revealing ours).

        * This is just like send_reg otherwise

        */

        private void  cookieError(OtpLocalNode local, Erlang.Atom cookie)

        {

            try

            {

                OtpOutputStream header = new OtpOutputStream(headerLen);

                

                // preamble: 4 byte length + "passthrough" tag + version

                header.write4BE(0); // reserve space for length

                header.write1(passThrough);

                header.write1(version);

                

                header.write_tuple_head(4);

                header.write_long((long)OtpMsg.Tag.regSendTag);

                header.write_any(local.createPid()); // disposable pid

                header.write_atom(cookie.atomValue()); // important: his cookie, not mine...

                header.write_atom("auth");

                

                // version for payload

                header.write1(version);

                

                // the payload

                

                // the no_auth message (copied from Erlang) Don't change this (Erlang will crash)

                // {$gen_cast, {print, "~n** Unauthorized cookie ~w **~n", [foo@aule]}}

                Erlang.Object[] msg = new Erlang.Object[2];

                Erlang.Object[] msgbody = new Erlang.Object[3];

                

                msgbody[0] = new Erlang.Atom("print");

                msgbody[1] = new Erlang.String("~n** Bad cookie sent to " + local + " **~n");

                // Erlang will crash and burn if there is no third argument here...

                msgbody[2] = new Erlang.List(); // empty list

                

                msg[0] = new Erlang.Atom("$gen_cast");

                msg[1] = new Erlang.Tuple(msgbody);

                

                OtpOutputStream payload = new OtpOutputStream(new Erlang.Tuple(msg));

                

                // fix up length in preamble

                header.poke4BE(0, header.count() + payload.count() - 4);

                

                try

                {

                    do_send(header, payload);

                }

                catch (System.IO.IOException)

                {

                } // ignore

            }

            finally

            {

                close();

                throw new OtpAuthException("Remote cookie not authorized: " + cookie.atomValue());

            }

        }

        

        // link to pid

        

        /*

        * Create a link between the local node and the specified process on

        * the remote node. If the link is still active when the remote

        * process terminates, an exit signal will be sent to this

        * connection. Use {@link #sendUnlink unlink()} to remove the link.

        *

        * @param dest the Erlang PID of the remote process.

        *

        * @exception C#.io.IOException if the connection is not active

        * or a communication error occurs.

        **/

        protected internal virtual void  sendLink(Erlang.Pid from, Erlang.Pid dest)

        {

            if (!connected)

            {

                throw new System.IO.IOException("Not connected");

            }

            OtpOutputStream header = new OtpOutputStream(headerLen);

            

            // preamble: 4 byte length + "passthrough" tag

            header.write4BE(0); // reserve space for length

            header.write1(passThrough);

            header.write1(version);

            

            // header

            header.write_tuple_head(3);

            header.write_long((long)OtpMsg.Tag.linkTag);

            header.write_any(from);

            header.write_any(dest);

            

            // fix up length in preamble

            header.poke4BE(0, header.count() - 4);

            

            do_send(header);

        }

        

        /*

        * Remove a link between the local node and the specified process on

        * the remote node. This method deactivates links created with

        * {@link #sendLink link()}.

        *

        * @param dest the Erlang PID of the remote process.

        *

        * @exception C#.io.IOException if the connection is not active or

        * a communication error occurs.

        **/

        protected internal virtual void  sendUnlink(Erlang.Pid from, Erlang.Pid dest)

        {

            if (!connected)

            {

                throw new System.IO.IOException("Not connected");

            }

            OtpOutputStream header = new OtpOutputStream(headerLen);

            

            // preamble: 4 byte length + "passthrough" tag

            header.write4BE(0); // reserve space for length

            header.write1(passThrough);

            header.write1(version);

            

            // header

            header.write_tuple_head(3);

            header.write_long((long)OtpMsg.Tag.unlinkTag);

            header.write_any(from);

            header.write_any(dest);

            

            // fix up length in preamble

            header.poke4BE(0, header.count() - 4);

            

            do_send(header);

        }

        

        /*used internally when "processes" terminate */

        protected internal virtual void  sendExit(Erlang.Pid from, Erlang.Pid dest, System.String reason)

        {

            sendExit((int)OtpMsg.Tag.exitTag, from, dest, reason);

        }

        

        /*

        * Send an exit signal to a remote process.

        * 

        * @param dest the Erlang PID of the remote process.

        * @param reason a string describing the exit reason.

        * 

        * @exception C#.io.IOException if the connection is not active or

        * a communication error occurs.

        **/

        protected internal virtual void  sendExit2(Erlang.Pid from, Erlang.Pid dest, System.String reason)

        {

            sendExit((int)OtpMsg.Tag.exit2Tag, from, dest, reason);

        }



        private void  sendExit(int tag, Erlang.Pid from, Erlang.Pid dest, System.String reason)

        {

            if (!connected)

            {

                throw new System.IO.IOException("Not connected");

            }

            OtpOutputStream header = new OtpOutputStream(headerLen);

            

            // preamble: 4 byte length + "passthrough" tag

            header.write4BE(0); // reserve space for length

            header.write1(passThrough);

            header.write1(version);

            

            // header

            header.write_tuple_head(4);

            header.write_long(tag);

            header.write_any(from);

            header.write_any(dest);

            header.write_string(reason);

            

            // fix up length in preamble

            header.poke4BE(0, header.count() - 4);

            

            do_send(header);

        }

        

        public virtual void Start()

        {

            if (!connected)

            {

                deliver(new System.IO.IOException("Not connected"));

                return ;

            }



            byte[] lbuf = new byte[4];

            OtpInputStream ibuf;

            Erlang.Object traceobj;

            int len;

            byte[] tock = new byte[]{0, 0, 0, 0};

            

            try

            {

                while (!done)

                {

                    // don't return until we get a real message

                    // or a failure of some kind (e.g. EXIT)

                    // read length and read buffer must be atomic!

                    do

                    {

                        // read 4 bytes - get length of incoming packet

                        // socket.getInputStream().read(lbuf);

                        int n;

                        if ((n = readSock(socket, lbuf)) < lbuf.Length)

                            throw new System.Exception("Read " + n + " out of " + lbuf.Length + " bytes!");



                        ibuf = new OtpInputStream(lbuf);

                        len = ibuf.read4BE();

                        

                        //  received tick? send tock!

                        if (len == 0)

                            lock(this)

                            {

                                System.Byte[] temp_bytearray;

                                temp_bytearray = tock;

                                if (socket != null)

                                    ((System.IO.Stream) socket.GetStream()).Write(temp_bytearray, 0, temp_bytearray.Length);

                            }

                        

                    }

                    while (len == 0); // tick_loop

                    

                    // got a real message (maybe) - read len bytes

                    byte[] tmpbuf = new byte[len];

                    // i = socket.getInputStream().read(tmpbuf);

                    int m = readSock(socket, tmpbuf);

                    if (m < len)

                        throw new System.Exception("Read " + m + " out of " + len + " bytes!");



                    ibuf = new OtpInputStream(tmpbuf);

                    

                    if (ibuf.read1() != passThrough)

                    {

                        goto receive_loop_brk;

                    }

                    

                    // got a real message (really)

                    Erlang.Atom reason = null;

                    Erlang.Atom cookie = null;

                    Erlang.Object tmp = null;

                    Erlang.Tuple head = null;

                    Erlang.Atom toName;

                    Erlang.Pid to;

                    Erlang.Pid from;

                    Erlang.Ref eref;

                    

                    // decode the header

                    tmp = ibuf.read_any();

                    if (!(tmp is Erlang.Tuple))

                    {

                        goto receive_loop_brk;

                    }

                    

                    head = (Erlang.Tuple) tmp;

                    if (!(head.elementAt(0) is Erlang.Long))

                    {

                        goto receive_loop_brk;

                    }

                    

                    // lets see what kind of message this is

                    OtpMsg.Tag tag = (OtpMsg.Tag)((Erlang.Long)(head.elementAt(0))).longValue();

                    

                    switch (tag)

                    {

                        case OtpMsg.Tag.sendTag:

                        case OtpMsg.Tag.sendTTTag: 

                            // { SEND, Cookie, ToPid, TraceToken }

                            if (!cookieOk)

                            {

                                // we only check this once, he can send us bad cookies later if he likes

                                if (!(head.elementAt(1) is Erlang.Atom))

                                {

                                    goto receive_loop_brk;

                                }

                                cookie = (Erlang.Atom) head.elementAt(1);

                                if (sendCookie)

                                {

                                    if (!cookie.atomValue().Equals(auth_cookie))

                                    {

                                        cookieError(self, cookie);

                                    }

                                }

                                else

                                {

                                    if (!cookie.atomValue().Equals(""))

                                    {

                                        cookieError(self, cookie);

                                    }

                                }

                                cookieOk = true;

                            }



                            if (traceLevel >= OtpTrace.Type.sendThreshold)

                            {

                                OtpTrace.TraceEvent("<- " + headerType(head) + " " + head.ToString());



                                /*show received payload too */

                                long mark = ibuf.Position;

                                traceobj = ibuf.read_any();



                                if (traceobj != null)

                                    OtpTrace.TraceEvent("   " + traceobj.ToString());

                                else

                                    OtpTrace.TraceEvent("   (null)");

                                ibuf.Seek(mark, System.IO.SeekOrigin.Begin);

                            }



                            to = (Erlang.Pid) (head.elementAt(2));



                            deliver(new OtpMsg(to, ibuf));

                            break;



                        case OtpMsg.Tag.regSendTag:

                        case OtpMsg.Tag.regSendTTTag:

                            // { REG_SEND, FromPid, Cookie, ToName, TraceToken }

                            if (!cookieOk)

                            {

                                // we only check this once, he can send us bad cookies later if he likes

                                if (!(head.elementAt(2) is Erlang.Atom))

                                {

                                    goto receive_loop_brk;

                                }

                                cookie = (Erlang.Atom) head.elementAt(2);

                                if (sendCookie)

                                {

                                    if (!cookie.atomValue().Equals(auth_cookie))

                                    {

                                        cookieError(self, cookie);

                                    }

                                }

                                else

                                {

                                    if (!cookie.atomValue().Equals(""))

                                    {

                                        cookieError(self, cookie);

                                    }

                                }

                                cookieOk = true;

                            }



                            if (traceLevel >= OtpTrace.Type.sendThreshold)

                            {

                                OtpTrace.TraceEvent("<- " + headerType(head) + " " + head.ToString());

                                

                                /*show received payload too */

                                long mark = ibuf.Position;

                                traceobj = ibuf.read_any();



                                if (traceobj != null)

                                    OtpTrace.TraceEvent("   " + traceobj.ToString());

                                else

                                    OtpTrace.TraceEvent("   (null)");

                                ibuf.Seek(mark, System.IO.SeekOrigin.Begin);

                            }



                            from = (Erlang.Pid) (head.elementAt(1));

                            toName = (Erlang.Atom) (head.elementAt(3));



                            deliver(new OtpMsg(from, toName.atomValue(), ibuf));

                            break;



                        case OtpMsg.Tag.exitTag:

                        case OtpMsg.Tag.exit2Tag:

                            // { EXIT2, FromPid, ToPid, Reason }

                            if (!(head.elementAt(3) is Erlang.Atom))

                            {

                                goto receive_loop_brk;

                            }

                            if (traceLevel >= OtpTrace.Type.ctrlThreshold)

                            {

                                OtpTrace.TraceEvent("<- " + headerType(head) + " " + head.ToString());

                            }

                            

                            from = (Erlang.Pid) (head.elementAt(1));

                            to = (Erlang.Pid) (head.elementAt(2));

                            reason = (Erlang.Atom) head.elementAt(3);

                            

                            deliver(new OtpMsg(tag, from, to, reason));

                            break;



                        case OtpMsg.Tag.exitTTTag:

                        case OtpMsg.Tag.exit2TTTag:

                            // { EXIT2, FromPid, ToPid, TraceToken, Reason }

                            // as above, but bifferent element number

                            if (!(head.elementAt(4) is Erlang.Atom))

                            {

                                goto receive_loop_brk;

                            }

                            if (traceLevel >= OtpTrace.Type.ctrlThreshold)

                            {

                                OtpTrace.TraceEvent("<- " + headerType(head) + " " + head.ToString());

                            }



                            from = (Erlang.Pid) (head.elementAt(1));

                            to = (Erlang.Pid) (head.elementAt(2));

                            reason = (Erlang.Atom) head.elementAt(4);



                            deliver(new OtpMsg(tag, from, to, reason));

                            break;



                        case OtpMsg.Tag.linkTag:

                        case OtpMsg.Tag.unlinkTag:

                            // { UNLINK, FromPid, ToPid}

                            if (traceLevel >= OtpTrace.Type.ctrlThreshold)

                            {

                                OtpTrace.TraceEvent("<- " + headerType(head) + " " + head.ToString());

                            }

                            

                            from = (Erlang.Pid) (head.elementAt(1));

                            to = (Erlang.Pid) (head.elementAt(2));



                            deliver(new OtpMsg(tag, from, to));

                            break;



                        // absolutely no idea what to do with these, so we ignore them...

                        case OtpMsg.Tag.groupLeaderTag:

                        case OtpMsg.Tag.nodeLinkTag:

                            // { NODELINK }

                            // (just show trace)

                            if (traceLevel >= OtpTrace.Type.ctrlThreshold)

                            {

                                OtpTrace.TraceEvent("<- " + headerType(head) + " " + head.ToString());

                            }

                            break;



                        case OtpMsg.Tag.monitorPTag:

                            // {MONITOR_P, FromPid, ToProc, Ref}

                        case OtpMsg.Tag.demonitorPTag:

                            // {DEMONITOR_P, FromPid, ToProc, Ref}

                            if (traceLevel >= OtpTrace.Type.ctrlThreshold)

                            {

                                OtpTrace.TraceEvent("<- " + headerType(head) + " " + head.ToString());

                            }

                            from = (Erlang.Pid)(head.elementAt(1));

                            to = (Erlang.Pid)(head.elementAt(2));

                            eref = (Erlang.Ref)(head.elementAt(3));

                            deliver(new OtpMsg(tag, from, to, eref));

                            break;



                        case OtpMsg.Tag.monitorPexitTag:

                            // {MONITOR_P_EXIT, FromPid, ToProc, Ref, Reason}

                            if (traceLevel >= OtpTrace.Type.ctrlThreshold)

                            {

                                OtpTrace.TraceEvent("<- " + headerType(head) + " " + head.ToString());

                            }

                            from = (Erlang.Pid)(head.elementAt(1));

                            to = (Erlang.Pid)(head.elementAt(2));

                            eref = (Erlang.Ref)(head.elementAt(3));



                            deliver(new OtpMsg(tag, from, to, eref, reason));

                            break;



                        default:

                            // garbage?

                            if (traceLevel >= OtpTrace.Type.ctrlThreshold)

                            {

                                OtpTrace.TraceEvent("<- Unknown tag " + headerType(head) + " " + head.ToString());

                            }

                            goto receive_loop_brk;

                    }

                }

receive_loop_brk: ;

                 // end receive_loop



                // this section reachable only with break

                // we have received garbage from peer

                deliver(new Erlang.Exit("Remote is sending garbage"));



            }

            catch (OtpAuthException e)

            {

                deliver(e);

            }

            catch (Erlang.Exception e)

            {

                OtpTrace.TraceEvent(e.ToString());

                deliver(new Erlang.Exit("Remote is sending garbage: " + e.ToString()));

            }

            catch (System.Exception e)

            {

                deliver(new Erlang.Exit("Remote has closed connection: " + e.ToString()));

            }

            finally

            {

                close();

                OtpTrace.TraceEvent("exit connection "+System.Threading.Thread.CurrentThread.Name);

            }

        }



        /*

        * Close the connection to the remote node.

        **/

        public virtual void  close()

        {

            done = true;

            connected = false;

            lock(this)

            {

                try

                {

                    if (socket != null)

                    {

                        if (traceLevel >= OtpTrace.Type.ctrlThreshold)

                        {

                            OtpTrace.TraceEvent("-> CLOSE");

                        }

                        socket.Close();

                        //thread.Interrupt();

                    }

                }

                catch (System.Net.Sockets.SocketException)

                {

                    /*ignore socket close errors */

                }

                finally

                {

                    socket = null;

                }

            }

        }



        ~AbstractConnection()

        {

            close();

        }



        /*

        * Determine if the connection is still alive. Note that this method

        * only reports the status of the connection, and that it is

        * possible that there are unread messages waiting in the receive

        * queue.

        *

        * @return true if the connection is alive.

        **/

        public virtual bool isConnected()

        {

            return connected;

        }



        /*

        * Send an RPC request to the remote Erlang node. This convenience

        * function creates the following message and sends it to 'rex' on

        * the remote node:

        * 

        * <pre>

        * { self, { call, Mod, Fun, Args, user }}

        * </pre>

        *

        * <p> Note that this method has unpredicatble results if the remote

        * node is not an Erlang node. </p>

        *

        * @param mod the name of the Erlang module containing the function to be called.

        * @param fun the name of the function to call.

        * @param args a list of Erlang terms, to be used as arguments to the function.

        *

        * @exception C#.io.IOException if the connection is not active

        * or a communication error occurs.

        **/

        public virtual void sendRPC(Erlang.Pid from, System.String mod, System.String fun, Erlang.List args)

        {

            Erlang.Object rpc = encodeRPC(from, mod, fun, args, new Erlang.Atom("user"));

            sendBuf(from, "rex", new OtpOutputStream(rpc));

        }



        /*

        * Send an RPC cast request to the remote Erlang node. This convenience

        * function creates the following message and sends it to 'rex' on

        * the remote node:

        * 

        * <pre>

        * { self, { cast, Mod, Fun, Args, user }}

        * </pre>

        *

        * No reply is delivered back

        * <p> Note that this method has unpredicatble results if the remote

        * node is not an Erlang node. </p>

        *

        * @param mod the name of the Erlang module containing the function to be called.

        * @param fun the name of the function to call.

        * @param args a list of Erlang terms, to be used as arguments to the function.

        *

        * @exception C#.io.IOException if the connection is not active

        * or a communication error occurs.

        **/

        public virtual void sendRPCcast(Erlang.Pid from, string mod, string fun, Erlang.List args)

        {

            Erlang.Object rpc = encodeRPCcast(from, mod, fun, args, new Erlang.Atom("user"));

            sendBuf(from, "rex", new OtpOutputStream(rpc));

        }



        internal static Erlang.Tuple encodeRPC(

            Erlang.Pid from, string mod, string fun, Erlang.List args, Erlang.Object gleader)

        {

            return encodeRPC(from, new Erlang.Atom(mod), new Erlang.Atom(fun), args, gleader);

        }



        internal static Erlang.Tuple encodeRPCcast(

            Erlang.Pid from, string mod, string fun, Erlang.List args, Erlang.Object gleader)

        {

            return encodeRPCcast(from, new Erlang.Atom(mod), new Erlang.Atom(fun), args, gleader);

        }



        internal static Erlang.Tuple encodeRPC(

            Erlang.Pid from, Erlang.Atom mod, Erlang.Atom fun, Erlang.List args, Erlang.Object gleader)

        {

            /*{self, { cast, Mod, Fun, Args, user}} */

            return new Erlang.Tuple(

                from,

                new Erlang.Tuple(new Erlang.Atom("call"), mod, fun, args, gleader)

            );

        }



        internal static Erlang.Tuple encodeRPCcast(

            Erlang.Pid from, Erlang.Atom mod, Erlang.Atom fun, Erlang.List args, Erlang.Object gleader)

        {

            /*{'$gen_cast', { cast, Mod, Fun, Args, user}} */

            return new Erlang.Tuple(

                    new Erlang.Atom("$gen_cast"), 

                    new Erlang.Tuple(new Erlang.Atom("cast"), mod, fun, args, gleader));

        }



        internal static Erlang.Object decodeRPC(Erlang.Object msg)

        {

            if (msg is Erlang.Tuple)

            {

                Erlang.Tuple t = (Erlang.Tuple)msg;

                if (t.arity() == 2)

                {

                    Erlang.Atom rex = t[0] as Erlang.Atom;

                    if (rex != null && rex.atomValue() == "rex")

                        return t[1];

                    // obs: second element

                }

            }

            return null;

        }



        internal static string decodeIO(Erlang.Object msg)

        {

            if (msg is Erlang.Tuple)

            {

                Erlang.Tuple t = (Erlang.Tuple)msg;

                if (t.arity() == 4)

                {

                    Erlang.Atom  ios = t[0] as Erlang.Atom;

                    Erlang.Tuple data = t[3] as Erlang.Tuple;

                    if (ios != null && ios.atomValue() == "io_request" && data != null)

                    {

                        if ((data[0] as Erlang.Atom).atomValue() == "put_chars")

                        {

                            if (data[1] is Erlang.String)

                                return (data[1] as Erlang.String).stringValue();

                            else if (data[1] is Erlang.Binary)

                            {

                                byte[] bin = (data[1] as Erlang.Binary).binaryValue();

                                char[] s = new char[bin.Length];

                                bin.CopyTo(s, 0);

                                return new string(s);

                            }

                            else

                                return data[1].ToString();

                        }

                    }

                }

            }

            return null;

        }



        // used by  send and send_reg (message types with payload)

        protected internal virtual void  do_send(OtpOutputStream header, OtpOutputStream payload)

        {

            lock(this)

            {

                try

                {

                    if (traceLevel >= OtpTrace.Type.sendThreshold)

                    {

                        // Need to decode header and output buffer to show trace message!

                        // First make OtpInputStream, then decode.

                        try

                        {

                            Erlang.Object h = (header.getOtpInputStream(5)).read_any();

                            OtpTrace.TraceEvent("-> " + headerType(h) + " " + h.ToString());

                            

                            Erlang.Object o = (payload.getOtpInputStream(0)).read_any();

                            OtpTrace.TraceEvent("   " + o.ToString());

                            o = null;

                        }

                        catch (Erlang.Exception e)

                        {

                            OtpTrace.TraceEvent("   " + "can't decode output buffer:" + e);

                        }

                    }

                    

                    header.writeTo((System.IO.Stream) socket.GetStream());

                    payload.writeTo((System.IO.Stream) socket.GetStream());

                }

                catch (System.Net.Sockets.SocketException e)

                {

                    close();

                    throw e;

                }

                catch (System.IO.IOException e)

                {

                    close();

                    throw e;

                }

            }

        }

        

        // used by the other message types

        protected internal virtual void  do_send(OtpOutputStream header)

        {

            lock(this)

            {

                try

                {

                    if (traceLevel >= OtpTrace.Type.ctrlThreshold)

                    {

                        try

                        {

                            Erlang.Object h = (header.getOtpInputStream(5)).read_any();

                            OtpTrace.TraceEvent("-> " + headerType(h) + " " + h);

                        }

                        catch (Erlang.Exception e)

                        {

                            OtpTrace.TraceEvent("   " + "can't decode output buffer: " + e);

                        }

                    }

                    header.writeTo((System.IO.Stream) socket.GetStream());

                }

                catch (System.Net.Sockets.SocketException e)

                {

                    close();

                    throw e;

                }

                catch (System.IO.IOException e)

                {

                    close();

                    throw e;

                }

            }

        }



        protected internal virtual System.String headerType(Erlang.Object h)

        {

            OtpMsg.Tag tag = OtpMsg.Tag.undefined;



            if (h is Erlang.Tuple)

            {

                tag = (OtpMsg.Tag) (((Erlang.Long) (((Erlang.Tuple) h).elementAt(0))).longValue());

            }



            switch (tag)

            {

                case OtpMsg.Tag.linkTag:

                    return "LINK";



                case OtpMsg.Tag.sendTag:

                    return "SEND";



                case OtpMsg.Tag.exitTag:

                    return "EXIT";



                case OtpMsg.Tag.unlinkTag:

                    return "UNLINK";



                case OtpMsg.Tag.nodeLinkTag:

                    return "NODELINK";



                case OtpMsg.Tag.regSendTag:

                    return "REG_SEND";



                case OtpMsg.Tag.groupLeaderTag:

                    return "GROUP_LEADER";



                case OtpMsg.Tag.exit2Tag:

                    return "EXIT2";



                case OtpMsg.Tag.sendTTTag:

                    return "SEND_TT";



                case OtpMsg.Tag.exitTTTag:

                    return "EXIT_TT";



                case OtpMsg.Tag.regSendTTTag:

                    return "REG_SEND_TT";



                case OtpMsg.Tag.exit2TTTag:

                    return "EXIT2_TT";



                case OtpMsg.Tag.monitorPTag:

                    return "MONITOR_P";



                case OtpMsg.Tag.demonitorPTag:

                    return "DEMONITOR_P";



                case OtpMsg.Tag.monitorPexitTag:

                    return "MONITOR_P_EXIT";

            }

            return "(unknown type)";

        }

        

        /*this method now throws exception if we don't get full read */

        protected internal virtual int readSock(System.Net.Sockets.TcpClient s, byte[] b)

        {

            int got = 0;

            int len = (int) (b.Length);

            int i;

            System.IO.Stream is_Renamed = null;

            

            lock (this)

            {

                if (s == null)

                {

                    throw new System.IO.IOException("expected " + len + " bytes, socket was closed");

                }

                is_Renamed = (System.IO.Stream)s.GetStream();

            }



            while (got < len && is_Renamed.CanRead)

            {

                i = is_Renamed.Read(b, got, len - got);



                if (i < 0)

                {

                    throw new System.IO.IOException("Expected " + len + " bytes, got EOF after " + got + " bytes");

                }

                else if (i == 0)

                {

                    throw new System.IO.IOException("Remote connection closed");

                }

                else

                    got += i;

            }

            return got;

        }



        protected internal virtual void  doAccept()

        {

            try

            {

                sendStatus("ok");

                int our_challenge = genChallenge();

                sendChallenge(peer.distChoose, self.flags, our_challenge);

                int her_challenge = recvChallengeReply(our_challenge);

                byte[] our_digest = genDigest(her_challenge, auth_cookie);

                sendChallengeAck(our_digest);

                connected = true;

                cookieOk = true;

                sendCookie = false;

            }

            catch (System.Net.Sockets.SocketException ie)

            {

                close();

                throw new System.IO.IOException(ie.ToString());

            }

            catch (OtpAuthException ae)

            {

                close();

                throw ae;

            }

            catch (System.Exception)

            {

                System.String nn = peer.node();

                close();

                throw new System.IO.IOException("Error accepting connection from " + nn);

            }

            if (traceLevel >= OtpTrace.Type.handshakeThreshold)

                OtpTrace.TraceEvent("<- MD5 ACCEPTED " + peer.host());

        }

        

        protected internal virtual void  doConnect(int port)

        {

            try

            {

                socket = new System.Net.Sockets.TcpClient(peer.host(), port);

                socket.NoDelay = true;

                

                Debug.WriteLine("-> MD5 CONNECT TO " + peer.host() + ": " + port);

                

                if (traceLevel >= OtpTrace.Type.handshakeThreshold)

                    OtpTrace.TraceEvent("-> MD5 CONNECT TO " + peer.host() + ":" + port);

                sendName(peer.distChoose, self.flags);

                recvStatus();

                int her_challenge = recvChallenge();

                byte[] our_digest = genDigest(her_challenge, auth_cookie);

                int our_challenge = genChallenge();

                sendChallengeReply(our_challenge, our_digest);

                recvChallengeAck(our_challenge);

                cookieOk = true;

                sendCookie = false;

            }

            catch (OtpAuthException ae)

            {

                close();

                throw ae;

            }

            catch (System.Net.Sockets.SocketException e)

            {

                close();

                throw new System.IO.IOException("Cannot connect to peer node: " + e.ToString());

            }

        }

        

        // This is nooo good as a challenge,

        // XXX fix me.

        static protected internal int genChallenge()

        {

            return random.Next();

        }

        

        // Used to debug print a message digest

        internal static System.String hex0(byte x)

        {

            char[] tab = new char[]{'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};

            int uint_Renamed;

            if (x < 0)

            {

                uint_Renamed = x & 0x7F;

                uint_Renamed |= (1 << 7);

            }

            else

            {

                uint_Renamed = (int) x;

            }

            return "" + tab[SupportClass.URShift(uint_Renamed, 4)] + tab[uint_Renamed & 0xF];

        }

        

        internal static System.String hex(byte[] b)

        {

            System.Text.StringBuilder sb = new System.Text.StringBuilder();

            try

            {

                int i;

                 for (i = 0; i < b.Length; ++i)

                    sb.Append(hex0(b[i]));

            }

            catch (System.Exception)

            {

                // Debug function, ignore errors.

            }

            return sb.ToString();

            

        }

        

        protected internal virtual byte[] genDigest(int challenge, System.String…

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