introduced a proper half open TCP connection limit. Also exposed the connection queue to let clients use the same connection limiter as libtorrent. UPnP connections and tracker connection are now also limited as well as peer connections and web seeds

2007-05-05 00:29:33 +00:00
parent 4000cc6ac3
commit 49bd69cad4
26 changed files with 488 additions and 216 deletions
--- a/src/connection_queue.cpp
+++ b/src/connection_queue.cpp
@@ -0,0 +1,163 @@
+
+/*
+
+Copyright (c) 2007, Arvid Norberg
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions
+are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+    * Redistributions in binary form must reproduce the above copyright
+      notice, this list of conditions and the following disclaimer in
+      the documentation and/or other materials provided with the distribution.
+    * Neither the name of the author nor the names of its
+      contributors may be used to endorse or promote products derived
+      from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
+
+*/
+
+#include <boost/bind.hpp>
+#include "libtorrent/invariant_check.hpp"
+#include "libtorrent/connection_queue.hpp"
+
+namespace libtorrent
+{
+
+	connection_queue::connection_queue(io_service& ios): m_next_ticket(0)
+		, m_num_connecting(0)
+		, m_half_open_limit(0)
+		, m_timer(ios)
+	{}
+
+	bool connection_queue::free_slots() const
+	{ return m_num_connecting < m_half_open_limit || m_half_open_limit <= 0; }
+
+	void connection_queue::enqueue(boost::function<void(int)> const& on_connect
+		, boost::function<void()> const& on_timeout
+		, time_duration timeout)
+	{
+		INVARIANT_CHECK;
+
+		m_queue.push_back(entry());
+		entry& e = m_queue.back();
+		e.on_connect = on_connect;
+		e.on_timeout = on_timeout;
+		e.ticket = m_next_ticket;
+		e.timeout = timeout;
+		++m_next_ticket;
+		try_connect();
+	}
+
+	void connection_queue::done(int ticket)
+	{
+		INVARIANT_CHECK;
+
+		std::list<entry>::iterator i = std::find_if(m_queue.begin()
+			, m_queue.end(), boost::bind(&entry::ticket, _1) == ticket);
+		if (i == m_queue.end())
+		{
+			// this might not be here in case on_timeout calls remove
+			return;
+		}
+		if (i->connecting) --m_num_connecting;
+		m_queue.erase(i);
+		try_connect();
+	}
+
+	void connection_queue::limit(int limit)
+	{ m_half_open_limit = limit; }
+
+	int connection_queue::limit() const
+	{ return m_half_open_limit; }
+
+#ifndef NDEBUG
+
+	void connection_queue::check_invariant() const
+	{
+		int num_connecting = 0;
+		for (std::list<entry>::const_iterator i = m_queue.begin();
+			i != m_queue.end(); ++i)
+		{
+			if (i->connecting) ++num_connecting;
+		}
+		assert(num_connecting == m_num_connecting);
+	}
+
+#endif
+
+	void connection_queue::try_connect()
+	{
+		INVARIANT_CHECK;
+
+		if (!free_slots() || m_queue.empty())
+			return;
+
+		std::list<entry>::iterator i = std::find_if(m_queue.begin()
+			, m_queue.end(), boost::bind(&entry::connecting, _1) == false);
+		while (i != m_queue.end())
+		{
+			ptime expire = time_now() + i->timeout;
+			if (m_num_connecting == 0)
+			{
+				m_timer.expires_at(expire);
+				m_timer.async_wait(boost::bind(&connection_queue::on_timeout, this, _1));
+			}
+			i->connecting = true;
+			++m_num_connecting;
+			i->expires = expire;
+			try { i->on_connect(i->ticket); } catch (std::exception&) {}
+
+			if (!free_slots()) break;
+			i = std::find_if(i, m_queue.end(), boost::bind(&entry::connecting, _1) == false);
+		}
+	}
+
+	void connection_queue::on_timeout(asio::error_code const& e)
+	{
+		INVARIANT_CHECK;
+
+		assert(!e || e == asio::error::operation_aborted);
+		if (e) return;
+
+		ptime next_expire = max_time();
+		ptime now = time_now();
+		for (std::list<entry>::iterator i = m_queue.begin();
+			i != m_queue.end();)
+		{
+			if (i->connecting && i->expires < now)
+			{
+				boost::function<void()> on_timeout = i->on_timeout;
+				i = m_queue.erase(i);
+				--m_num_connecting;
+				try { on_timeout(); } catch (std::exception&) {}
+				continue;
+			}
+			if (i->expires < next_expire)
+				next_expire = i->expires;
+			++i;
+		}
+		if (next_expire < max_time())
+		{
+			m_timer.expires_at(next_expire);
+			m_timer.async_wait(boost::bind(&connection_queue::on_timeout, this, _1));
+		}
+		try_connect();
+	}
+
+}
+