2008-02-01 Tatsuhiro Tsujikawa <tujikawa at rednoah dot com>

Added DHT functionality, compatible with mainline.
	DHT is disabled by default. To enable it, give --enable-dht to 
aria2c.
	You may need to specify entry point to DHT network using
	--dht-entry-point. DHT uses UDP port to listen incoming message.
	Use --dht-listen-port to specify port number. Make sure that 
your
	firewall configuration can pass through UDP traffic to the port.
	The routing table is saved in $HOME/.aria2/dht.dat.
	* src/DHT*
	* src/BNode.{h, cc}
	* src/PeerInteractionCommand.cc: enable DHT functionality for a
	particular torrent.
	* src/Data.cc: Rewritten ctor.
	* src/OptionHandlerFactory.cc: Added --enable-dht, 
--dht-listen-port,
	--dht-entry-point.
	* src/DefaultBtInteractive.cc: Send port message if dht is 
enabled.
	* src/RequestGroup.cc: Initialize DHT functionality. When 
download
	ends, remove BtContext from DHTPeerAnnounceStorage.
	* src/BtPortMessage.{h, cc}: Rewritten.
	* src/message.h
	* src/OptionHandlerImpl.cc
	* src/option_processing.cc: Added --enable-dht, 
--dht-listen-port,
	--dht-entry-point.
	* src/Dictionary.{h, cc} (remove): New function.
	* src/prefs.h
	* src/DefaultBtMessageFactory.h
	* src/BtHandshakeMessage.cc
	* src/ActivePeerConnectionCommand.cc
	* src/SocketCore.{h, cc}: Added datagram socket support.
	* src/DefaultBtMessageFactory.cc
	* src/BtSetup.cc: Add BtContext to DHTPeerAnnounceStorage here.
	Create DHT commands.
	* src/BtMessageFactory.h
	* src/PeerMessageUtil.{h, cc}

src/DHTEntryPointNameResolveCommand.cc

@@ -0,0 +1,161 @@
+/* <!-- copyright */
+/*
+ * aria2 - The high speed download utility
+ *
+ * Copyright (C) 2006 Tatsuhiro Tsujikawa
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ * In addition, as a special exception, the copyright holders give
+ * permission to link the code of portions of this program with the
+ * OpenSSL library under certain conditions as described in each
+ * individual source file, and distribute linked combinations
+ * including the two.
+ * You must obey the GNU General Public License in all respects
+ * for all of the code used other than OpenSSL.  If you modify
+ * file(s) with this exception, you may extend this exception to your
+ * version of the file(s), but you are not obligated to do so.  If you
+ * do not wish to do so, delete this exception statement from your
+ * version.  If you delete this exception statement from all source
+ * files in the program, then also delete it here.
+ */
+/* copyright --> */
+#include "DHTEntryPointNameResolveCommand.h"
+#include "DownloadEngine.h"
+#include "NameResolver.h"
+#include "DNSCache.h"
+#include "DlAbortEx.h"
+#include "prefs.h"
+#include "message.h"
+#include "Util.h"
+#include "Option.h"
+#include "DHTNode.h"
+#include "DHTTaskQueue.h"
+#include "DHTTaskFactory.h"
+#include "DHTTask.h"
+#include "RequestGroupMan.h"
+
+DHTEntryPointNameResolveCommand::DHTEntryPointNameResolveCommand(int32_t cuid, DownloadEngine* e):
+  Command(cuid),
+  _e(e),
+  _resolver(new NameResolver()),
+  _taskQueue(0),
+  _taskFactory(0),
+  _localNode(0)
+{}
+
+DHTEntryPointNameResolveCommand::~DHTEntryPointNameResolveCommand()
+{
+#ifdef ENABLE_ASYNC_DNS
+  disableNameResolverCheck(_resolver);
+#endif // ENABLE_ASYNC_DNS
+}
+
+bool DHTEntryPointNameResolveCommand::execute()
+{
+  if(_e->_requestGroupMan->downloadFinished() || _e->isHaltRequested()) {
+    return true;
+  }
+
+  try {
+    string hostname = _e->option->get(PREF_DHT_ENTRY_POINT_HOST);
+    if(!Util::isNumbersAndDotsNotation(hostname)) {
+      if(resolveHostname(hostname, _resolver)) {
+	hostname = _resolver->getAddrString();
+      } else {
+	_e->commands.push_back(this);
+	return false;
+      }
+    }
+    
+    DHTNodeHandle entryNode = new DHTNode();
+    entryNode->setIPAddress(hostname);
+    entryNode->setPort(_e->option->getAsInt(PREF_DHT_ENTRY_POINT_PORT));
+ 
+    _taskQueue->addPeriodicTask1(_taskFactory->createPingTask(entryNode, 10));
+    _taskQueue->addPeriodicTask1(_taskFactory->createNodeLookupTask(_localNode->getID()));
+    _taskQueue->addPeriodicTask1(_taskFactory->createBucketRefreshTask());
+  } catch(RecoverableException* e) {
+    logger->error(EX_EXCEPTION_CAUGHT, e);
+    delete e;
+  }
+  return true;
+}
+
+bool DHTEntryPointNameResolveCommand::resolveHostname(const string& hostname,
+						      const NameResolverHandle& resolver)
+{
+  string ipaddr = DNSCacheSingletonHolder::instance()->find(hostname);
+  if(ipaddr.empty()) {
+#ifdef ENABLE_ASYNC_DNS
+    switch(resolver->getStatus()) {
+    case NameResolver::STATUS_READY:
+      logger->info(MSG_RESOLVING_HOSTNAME, cuid, hostname.c_str());
+      resolver->resolve(hostname);
+      setNameResolverCheck(resolver);
+      return false;
+    case NameResolver::STATUS_SUCCESS:
+      logger->info(MSG_NAME_RESOLUTION_COMPLETE, cuid,
+		   hostname.c_str(), resolver->getAddrString().c_str());
+      DNSCacheSingletonHolder::instance()->put(hostname, resolver->getAddrString());
+      return true;
+      break;
+    case NameResolver::STATUS_ERROR:
+      throw new DlAbortEx(MSG_NAME_RESOLUTION_FAILED, cuid,
+			  hostname.c_str(),
+			  resolver->getError().c_str());
+    default:
+      return false;
+    }
+#else
+    logger->info(MSG_RESOLVING_HOSTNAME, cuid, hostname.c_str());
+    resolver->resolve(hostname);
+    logger->info(MSG_NAME_RESOLUTION_COMPLETE, cuid,
+		 hostname.c_str(), resolver->getAddrString().c_str());
+    DNSCacheSingletonHolder::instance()->put(hostname, resolver->getAddrString());
+    return true;
+#endif // ENABLE_ASYNC_DNS
+  } else {
+    logger->info(MSG_DNS_CACHE_HIT, cuid,
+		 hostname.c_str(), ipaddr.c_str());
+    resolver->setAddr(ipaddr);
+    return true;
+  }
+}
+
+#ifdef ENABLE_ASYNC_DNS
+void DHTEntryPointNameResolveCommand::setNameResolverCheck(const NameResolverHandle& resolver) {
+  _e->addNameResolverCheck(resolver, this);
+}
+
+void DHTEntryPointNameResolveCommand::disableNameResolverCheck(const NameResolverHandle& resolver) {
+  _e->deleteNameResolverCheck(resolver, this);
+}
+#endif // ENABLE_ASYNC_DNS
+
+void DHTEntryPointNameResolveCommand::setTaskQueue(const DHTTaskQueueHandle& taskQueue)
+{
+  _taskQueue = taskQueue;
+}
+
+void DHTEntryPointNameResolveCommand::setTaskFactory(const DHTTaskFactoryHandle& taskFactory)
+{
+  _taskFactory = taskFactory;
+}
+
+void DHTEntryPointNameResolveCommand::setLocalNode(const DHTNodeHandle& localNode)
+{
+  _localNode = localNode;
+}