/**
* When we get a new link message from an edge, we must
* check several conditions to see if we can proceed with
* the Link protocol.
* This function checks those conditions and returns true
* if we can proceed.
* If we cannot proceed, it gives an ErrorMessage to send
* back to the other side.
* @param cph The CphState
* @param err ErrorMessage to return. Is null if there is no error
* @return true if we can connect, if false, err != null
*/
protected bool CanConnect(CphState cph, out ErrorMessage err)
{
ConnectionTable tab = _node.ConnectionTable;
Address local_add = _node.Address;
LinkMessage lm = cph.LM;
err = null;
/* We lock the connection table so it doesn't change between
* the call to Contains and the call to Lock
*/
if( lm.Attributes["realm"] != _node.Realm ) {
err = new ErrorMessage(ErrorMessage.ErrorCode.RealmMismatch,
"We are not in the same realm");
}
else if( (lm.Remote.Address != null ) && !local_add.Equals( lm.Remote.Address ) ) {
/*
* They are trying to reach a specific node, but it's not
* us
*/
err = new ErrorMessage(ErrorMessage.ErrorCode.TargetMismatch,
String.Format("target is {0}, but reached {1}",
lm.Remote.Address, local_add));
}
else if( lm.Local.Address.Equals( local_add ) ) {
//You are me!!!
err = new ErrorMessage(ErrorMessage.ErrorCode.ConnectToSelf,
"You are me: ");
}
else if( 1 == _disconnecting ) {
err = new ErrorMessage(ErrorMessage.ErrorCode.Disconnecting,
String.Format("I am disconnecting. local: {0}", local_add));
}
else {
/*
* Now we go to the ConnectionTable and try to
* get a lock on the address so we can go forward
* with the linking
*/
try {
if(ProtocolLog.LinkDebug.Enabled)
ProtocolLog.Write(ProtocolLog.LinkDebug, String.Format(
"ConnectionPacketHandler - Trying to lock connection table: {0},{1}",
lm.Local.Address, lm.ConTypeString));
tab.Lock( lm.Local.Address, lm.ConTypeString, cph );
if(ProtocolLog.LinkDebug.Enabled)
ProtocolLog.Write(ProtocolLog.LinkDebug, String.Format(
"ConnectionPacketHandler - Successfully locked connection table: {0},{1}",
lm.Local.Address, lm.ConTypeString));
}
catch(ConnectionExistsException) {
//We already have a connection of this type to this address
err = new ErrorMessage(ErrorMessage.ErrorCode.AlreadyConnected,
String.Format("We are already connected: {0}", local_add));
}
catch(CTLockException) {
if(ProtocolLog.LinkDebug.Enabled)
ProtocolLog.Write(ProtocolLog.LinkDebug, String.Format(
"ConnectionPacketHandler - Cannot lock connection table: {0},{1}",
lm.Local.Address, lm.ConTypeString));
//Lock can throw this type of exception
err = new ErrorMessage(ErrorMessage.ErrorCode.InProgress,
"Address: " + lm.Local.Address.ToString() +
" is locked");
}
}
return ( err == null );
}
public LinkException(string message, bool crit, ErrorMessage em) : base(message) {
_critical = crit;
_em = em;
}
public void EMTest()
{
ErrorMessage em1 = new ErrorMessage(ErrorMessage.ErrorCode.UnexpectedRequest,
"Who are you???");
ErrorMessage em2 = new ErrorMessage(ErrorMessage.ErrorCode.AlreadyConnected, "We are BFF");
}
/**
* @param ec The ErrorCode for this message
* @param message the string in the message
*/
public ErrorMessage(ErrorMessage.ErrorCode ec, string message)
{
_ec = ec;;
_message = message;
}
/**
* This starts a linking operation on the given edge
*/
public IDictionary Start(IDictionary link_message, ISender edge)
{
if (ProtocolLog.LinkDebug.Enabled)
{
ProtocolLog.Write(ProtocolLog.LinkDebug, String.Format(
"{0} -start- sys:link.Start", _node.Address));
}
Edge from = GetEdge(edge);
LinkMessage lm = new LinkMessage(link_message);
if (ProtocolLog.LinkDebug.Enabled)
{
ProtocolLog.Write(ProtocolLog.LinkDebug, String.Format(
"{0} -args- sys:link.Start({1},{2})", _node.Address, lm, from));
}
CphState cph = new CphState(from, lm);
lock ( _sync ) {
if (!_edge_to_cphstate.ContainsKey(from))
{
_edge_to_cphstate[from] = cph;
}
else
{
throw new AdrException((int)ErrorMessage.ErrorCode.InProgress,
"Already have a link in progress on this edge");
}
}
ErrorMessage err = null;
if (CanConnect(cph, out err))
{
try {
//If the CloseEvent was already called, this throws an exception
from.CloseEvent += this.CloseHandler;
}
catch {
CloseHandler(from, null);
throw new AdrException((int)ErrorMessage.ErrorCode.EdgeClosed,
"Edge Closed after receiving message");
}
}
else
{
lock ( _sync ) {
_edge_to_cphstate.Remove(from);
}
}
//Now we prepare our response
LinkMessage lm_resp = null;
if (err == null)
{
//We send a response:
NodeInfo n_info = NodeInfo.CreateInstance(_node.Address, from.LocalTA);
NodeInfo remote_info = NodeInfo.CreateInstance(null, from.RemoteTA);
lm_resp = new LinkMessage(lm.ConTypeString, n_info, remote_info, _node.Realm, lm.Token);
}
else
{
throw new AdrException((int)err.Ec, err.Message);
}
if (ProtocolLog.LinkDebug.Enabled)
{
ProtocolLog.Write(ProtocolLog.LinkDebug, String.Format(
"{0} -end- sys:link.Start()->{1}", _node.Address, lm_resp));
}
return(lm_resp.ToDictionary());
}
