From dea237d2ed2eba1130f14046ae7c5a3cbf277058 Mon Sep 17 00:00:00 2001
From: Miguel Freitas <miguel@pitanga.cpti.cetuc.puc-rio.br>
Date: Wed, 7 Aug 2013 17:40:16 -0300
Subject: [PATCH] implement dht_get_data_alert to detect when we are neighbor
 of a certain request

---
 libtorrent/include/libtorrent/alert_types.hpp | 17 ++++++++++++++
 libtorrent/src/alert.cpp                      |  7 ++++++
 libtorrent/src/kademlia/node.cpp              | 22 ++++++++++++++++++
 src/twister.cpp                               | 23 ++++++++++++++++---
 4 files changed, 66 insertions(+), 3 deletions(-)

diff --git a/libtorrent/include/libtorrent/alert_types.hpp b/libtorrent/include/libtorrent/alert_types.hpp
index 54af2836..38165b0b 100644
--- a/libtorrent/include/libtorrent/alert_types.hpp
+++ b/libtorrent/include/libtorrent/alert_types.hpp
@@ -1163,6 +1163,23 @@ namespace libtorrent
 		entry::list_type const m_lst;
 	};
 
+	struct TORRENT_EXPORT dht_get_data_alert: alert
+	{
+		dht_get_data_alert(entry const& target, bool possiblyNeighbor, bool hasData)
+			: m_target(target), m_possiblyNeighbor(possiblyNeighbor), m_hasData(hasData)
+		{}
+
+		TORRENT_DEFINE_ALERT(dht_get_data_alert);
+
+		const static int static_category = alert::dht_notification;
+		virtual std::string message() const;
+
+		entry m_target;
+		bool  m_possiblyNeighbor;
+		bool  m_hasData;
+	};
+
+
 	struct TORRENT_EXPORT stats_alert: torrent_alert
 	{
 		stats_alert(torrent_handle const& h, int interval
diff --git a/libtorrent/src/alert.cpp b/libtorrent/src/alert.cpp
index 2647cccb..6aa99f2d 100644
--- a/libtorrent/src/alert.cpp
+++ b/libtorrent/src/alert.cpp
@@ -358,6 +358,13 @@ namespace libtorrent {
 		return msg;
 	}
 
+	std::string dht_get_data_alert::message() const
+	{
+		char msg[200];
+		snprintf(msg, sizeof(msg), "request of getData received (m_possiblyNeighbor=%d)", m_possiblyNeighbor);
+		return msg;
+	}
+
 	stats_alert::stats_alert(torrent_handle const& h, int in
 		, stat const& s)
 		: torrent_alert(h)
diff --git a/libtorrent/src/kademlia/node.cpp b/libtorrent/src/kademlia/node.cpp
index a7059a93..d2d6b4a6 100644
--- a/libtorrent/src/kademlia/node.cpp
+++ b/libtorrent/src/kademlia/node.cpp
@@ -1332,9 +1332,11 @@ void node_impl::incoming_request(msg const& m, entry& e)
 		m_table.find_node(target, n, 0);
 		write_nodes_entry(reply, n);
 
+		bool hasData = false;
 		dht_storage_table_t::iterator i = m_storage_table.find(target);
 		if (i != m_storage_table.end())
 		{
+			hasData = true;
 			reply["values"] = entry::list_type();
 			entry::list_type &values = reply["values"].list();
 
@@ -1349,6 +1351,26 @@ void node_impl::incoming_request(msg const& m, entry& e)
 				values.push_back(v);
 			}
 		}
+
+		// check distance between target, nodes and our own id
+		// n is sorted from closer(begin) to more distant (end)
+		bool possiblyNeighbor = false;
+		if( n.size() < m_table.bucket_size() ) {
+			possiblyNeighbor = true;
+		} else {
+			node_id dFarther = distance(n.back().id, target);
+			node_id dOwn     = distance(nid(), target);
+			if( dOwn < dFarther )
+				possiblyNeighbor = true;
+		}
+
+		if (m_post_alert)
+		{
+			entry eTarget;
+			eTarget = *msg_keys[mk_target];
+			alert* a = new dht_get_data_alert(eTarget,possiblyNeighbor,hasData);
+			if (!m_post_alert->post_alert(a)) delete a;
+		}
 	}
 	else
 	{
diff --git a/src/twister.cpp b/src/twister.cpp
index f357c949..d1da9089 100644
--- a/src/twister.cpp
+++ b/src/twister.cpp
@@ -170,6 +170,10 @@ void ThreadWaitExtIP()
                     , listen_port, listen_port+1, ec.message().c_str());
     }
 
+    dht_settings dhts;
+    dhts.restrict_routing_ips = false;
+    dhts.restrict_search_ips = false;
+    ses->set_dht_settings(dhts);
     ses->start_dht();
 
     //ses->set_settings(settings);
@@ -182,12 +186,12 @@ void ThreadMaintainDHTNodes()
     RenameThread("maintain-dht-nodes");
 
     while(1) {
-        MilliSleep(5000);
+        MilliSleep(15000);
 
         if( ses ) {
             session_status ss = ses->status();
-            if( ss.dht_nodes == 0 && vNodes.size() ) {
-                printf("ThreadMaintainDHTNodes: no dht_nodes, trying to add some...\n");
+            if( ss.dht_nodes < (int)vNodes.size() ) {
+                printf("ThreadMaintainDHTNodes: too few dht_nodes, trying to add some...\n");
                 LOCK(cs_vNodes);
                 BOOST_FOREACH(CNode* pnode, vNodes) {
                     BOOST_FOREACH(CAddress const &knownAddr, pnode->setAddrKnown) {
@@ -253,6 +257,19 @@ void ThreadSessionAlerts()
                     continue;
                 }
 
+                dht_get_data_alert const* gd = alert_cast<dht_get_data_alert>(*i);
+                if (gd)
+                {
+                    if( gd->m_possiblyNeighbor ) {
+                        printf("possiblyNeighbor of [%s,%s,%s]\n",
+                               gd->m_target.find_key("n")->string().c_str(),
+                               gd->m_target.find_key("r")->string().c_str(),
+                               gd->m_target.find_key("t")->string().c_str());
+                    }
+                    continue;
+                }
+
+
                 /*
                 save_resume_data_alert const* rd = alert_cast<save_resume_data_alert>(*i);
                 if (rd) {