premiere-libtorrent/src/upnp.cpp

/*

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 "libtorrent/pch.hpp"

#include "libtorrent/socket.hpp"
#include "libtorrent/upnp.hpp"
#include "libtorrent/io.hpp"
#include "libtorrent/parse_url.hpp"
#include "libtorrent/xml_parse.hpp"
#include "libtorrent/connection_queue.hpp"
#include "libtorrent/enum_net.hpp"
#include "libtorrent/escape_string.hpp"

#include <boost/bind.hpp>
#include <boost/ref.hpp>
#if BOOST_VERSION < 103500
#include <asio/ip/host_name.hpp>
#include <asio/ip/multicast.hpp>
#else
#include <boost/asio/ip/host_name.hpp>
#include <boost/asio/ip/multicast.hpp>
#endif
#include <boost/thread/mutex.hpp>
#include <cstdlib>

using boost::bind;
using namespace libtorrent;

static error_code ec;

upnp::upnp(io_service& ios, connection_queue& cc
	, address const& listen_interface, std::string const& user_agent
	, portmap_callback_t const& cb, bool ignore_nonrouters, void* state)
	:  m_user_agent(user_agent)
	, m_callback(cb)
	, m_retry_count(0)
	, m_io_service(ios)
	, m_socket(ios, udp::endpoint(address_v4::from_string("239.255.255.250", ec), 1900)
		, bind(&upnp::on_reply, self(), _1, _2, _3), false)
	, m_broadcast_timer(ios)
	, m_refresh_timer(ios)
	, m_disabled(false)
	, m_closing(false)
	, m_ignore_non_routers(ignore_nonrouters)
	, m_cc(cc)
{
	TORRENT_ASSERT(cb);
	m_retry_count = 0;

	if (state)
	{
		upnp_state_t* s = (upnp_state_t*)state;
		m_devices.swap(s->devices);
		m_mappings.swap(s->mappings);
		delete s;
	}
}

void* upnp::drain_state()
{
	upnp_state_t* s = new upnp_state_t;
	s->mappings.swap(m_mappings);

	for (std::set<rootdevice>::iterator i = m_devices.begin()
		, end(m_devices.end()); i != end; ++i)
		i->upnp_connection.reset();
	s->devices.swap(m_devices);
	return s;
}

upnp::~upnp()
{
}

void upnp::discover_device()
{
	mutex_t::scoped_lock l(m_mutex);
	if (m_socket.num_send_sockets() == 0)
		log("No network interfaces to broadcast to");

	discover_device_impl();
}

void upnp::log(std::string const& msg)
{
	m_callback(-1, 0, msg);
}

void upnp::discover_device_impl()
{
	const char msearch[] = 
		"M-SEARCH * HTTP/1.1\r\n"
		"HOST: 239.255.255.250:1900\r\n"
		"ST:upnp:rootdevice\r\n"
		"MAN:\"ssdp:discover\"\r\n"
		"MX:3\r\n"
		"\r\n\r\n";

	error_code ec;
#ifdef TORRENT_DEBUG_UPNP
	// simulate packet loss
	if (m_retry_count & 1)
#endif
	m_socket.send(msearch, sizeof(msearch) - 1, ec);

	if (ec)
	{
		std::stringstream msg;
		msg << "broadcast failed: " << ec.message() << ". Aborting.";
		log(msg.str());
		disable(ec.message().c_str());
		return;
	}

	++m_retry_count;
	m_broadcast_timer.expires_from_now(seconds(2 * m_retry_count), ec);
	m_broadcast_timer.async_wait(bind(&upnp::resend_request
		, self(), _1));

	log("broadcasting search for rootdevice");
}

// returns a reference to a mapping or -1 on failure
int upnp::add_mapping(upnp::protocol_type p, int external_port, int local_port)
{
	mutex_t::scoped_lock l(m_mutex);

	std::stringstream msg;
	msg << "adding port map: [ protocol: " << (p == tcp?"tcp":"udp")
		<< " ext_port: " << external_port
		<< " local_port: " << local_port << " ]";
	if (m_disabled) msg << " DISABLED";
	log(msg.str());
	if (m_disabled) return -1;

	std::vector<global_mapping_t>::iterator i = std::find_if(
		m_mappings.begin(), m_mappings.end()
		, boost::bind(&global_mapping_t::protocol, _1) == int(none));

	if (i == m_mappings.end())
	{
		m_mappings.push_back(global_mapping_t());
		i = m_mappings.end() - 1;
	}

	i->protocol = p;
	i->external_port = external_port;
	i->local_port = local_port;

	int mapping_index = i - m_mappings.begin();

	for (std::set<rootdevice>::iterator i = m_devices.begin()
		, end(m_devices.end()); i != end; ++i)
	{
		rootdevice& d = const_cast<rootdevice&>(*i);
		TORRENT_ASSERT(d.magic == 1337);

		if (int(d.mapping.size()) <= mapping_index)
			d.mapping.resize(mapping_index + 1);
		mapping_t& m = d.mapping[mapping_index];

		m.action = mapping_t::action_add;
		m.protocol = p;
		m.external_port = external_port;
		m.local_port = local_port;

		if (d.service_namespace) update_map(d, mapping_index);
	}

	return mapping_index;
}

void upnp::delete_mapping(int mapping)
{
	mutex_t::scoped_lock l(m_mutex);

	if (mapping <= int(m_mappings.size())) return;

	global_mapping_t& m = m_mappings[mapping];

	std::stringstream msg;
	msg << "deleting port map: [ protocol: " << (m.protocol == tcp?"tcp":"udp")
		<< " ext_port: " << m.external_port
		<< " local_port :" << m.local_port << " ]";
	log(msg.str());

	if (m.protocol == none) return;
	
	for (std::set<rootdevice>::iterator i = m_devices.begin()
		, end(m_devices.end()); i != end; ++i)
	{
		rootdevice& d = const_cast<rootdevice&>(*i);
		TORRENT_ASSERT(d.magic == 1337);

		TORRENT_ASSERT(mapping < int(d.mapping.size()));
		d.mapping[mapping].action = mapping_t::action_delete;

		if (d.service_namespace) update_map(d, mapping);
	}
}

bool upnp::get_mapping(int index, int& local_port, int& external_port, int& protocol) const
{
	TORRENT_ASSERT(index < int(m_mappings.size()) && index >= 0);
	if (index >= int(m_mappings.size()) || index < 0) return false;
	global_mapping_t const& m = m_mappings[index];
	if (m.protocol == none) return false;
	local_port = m.local_port;
	external_port = m.external_port;
	protocol = m.protocol;
	return true;
}

void upnp::resend_request(error_code const& e)
{
	if (e) return;

	mutex_t::scoped_lock l(m_mutex);

	if (m_closing) return;

	if (m_retry_count < 12
		&& (m_devices.empty() || m_retry_count < 4))
	{
		discover_device_impl();
		return;
	}

	if (m_devices.empty())
	{
		disable("no UPnP router found (no response)");
		return;
	}
	
	for (std::set<rootdevice>::iterator i = m_devices.begin()
		, end(m_devices.end()); i != end; ++i)
	{
		if (i->control_url.empty() && !i->upnp_connection && !i->disabled)
		{
			// we don't have a WANIP or WANPPP url for this device,
			// ask for it
			rootdevice& d = const_cast<rootdevice&>(*i);
			TORRENT_ASSERT(d.magic == 1337);
#ifndef BOOST_NO_EXCEPTIONS
			try
			{
#endif
				std::stringstream msg;
				msg << "connecting to: " << d.url;
				log(msg.str());
				if (d.upnp_connection) d.upnp_connection->close();
				d.upnp_connection.reset(new http_connection(m_io_service
					, m_cc, bind(&upnp::on_upnp_xml, self(), _1, _2
					, boost::ref(d), _5)));
				d.upnp_connection->get(d.url, seconds(30), 1);
#ifndef BOOST_NO_EXCEPTIONS
			}
			catch (std::exception& e)
			{
				(void)e;
				std::stringstream msg;
				msg << "connection failed to: " << d.url << " " << e.what();
				log(msg.str());
				d.disabled = true;
			}
#endif
		}
	}
}

void upnp::on_reply(udp::endpoint const& from, char* buffer
	, std::size_t bytes_transferred)
{
	mutex_t::scoped_lock l(m_mutex);

	using namespace libtorrent::detail;

	// parse out the url for the device

/*
	the response looks like this:

	HTTP/1.1 200 OK
	ST:upnp:rootdevice
	USN:uuid:000f-66d6-7296000099dc::upnp:rootdevice
	Location: http://192.168.1.1:5431/dyndev/uuid:000f-66d6-7296000099dc
	Server: Custom/1.0 UPnP/1.0 Proc/Ver
	EXT:
	Cache-Control:max-age=180
	DATE: Fri, 02 Jan 1970 08:10:38 GMT

	a notification looks like this:

	NOTIFY * HTTP/1.1
	Host:239.255.255.250:1900
	NT:urn:schemas-upnp-org:device:MediaServer:1
	NTS:ssdp:alive
	Location:http://10.0.3.169:2869/upnphost/udhisapi.dll?content=uuid:c17f0c32-d19b-4938-ae94-65f945c3a26e
	USN:uuid:c17f0c32-d19b-4938-ae94-65f945c3a26e::urn:schemas-upnp-org:device:MediaServer:1
	Cache-Control:max-age=900
	Server:Microsoft-Windows-NT/5.1 UPnP/1.0 UPnP-Device-Host/1.0

*/
	error_code ec;
	if (!in_local_network(m_io_service, from.address(), ec))
	{
		if (ec)
		{
			std::stringstream msg;
			msg << "when receiving response from: " << from << ": " << ec.message();
			log(msg.str());
		}
		else
		{
			std::stringstream msg;
			msg << "ignoring response from: " << from << ". IP is not on local network. ";

			std::vector<ip_interface> net = enum_net_interfaces(m_io_service, ec);
			for (std::vector<ip_interface>::const_iterator i = net.begin()
				, end(net.end()); i != end; ++i)
			{
				msg << "(" << i->interface_address << ", " << i->netmask << ") ";
			}
			log(msg.str());
		}
		return;
	} 

	if (m_ignore_non_routers)
	{
		std::vector<ip_route> routes = enum_routes(m_io_service, ec);
		if (std::find_if(routes.begin(), routes.end()
			, bind(&ip_route::gateway, _1) == from.address()) == routes.end())
		{
			// this upnp device is filtered because it's not in the
			// list of configured routers
			if (ec)
			{
				std::stringstream msg;
				msg << "when receiving response from: " << from << ": " << ec.message();
				log(msg.str());
			}
			else
			{
				std::stringstream msg;
				msg << "ignoring response from: " << from << ". IP is not a router. ";
				for (std::vector<ip_route>::const_iterator i = routes.begin()
					, end(routes.end()); i != end; ++i)
				{
					msg << "(" << i->gateway << ", " << i->netmask << ") ";
				}
				log(msg.str());
			}
			return;
		}
	}

	http_parser p;
	bool error = false;
	p.incoming(buffer::const_interval(buffer
		, buffer + bytes_transferred), error);
	if (error)
	{
		std::stringstream msg;
		msg << "received malformed HTTP from " << from;
		log(msg.str());
		return;
	}

	if (p.status_code() != 200 && p.method() != "notify")
	{
		if (p.method().empty())
		{
			std::stringstream msg;
			msg << "HTTP status " << p.status_code() << " from " << from;
			log(msg.str());
		}
		else
		{
			std::stringstream msg;
			msg << "HTTP method " << p.method() << " from " << from;
			log(msg.str());
		}
		return;
	}

	if (!p.header_finished())
	{
		std::stringstream msg;
		msg << "incomplete HTTP packet from " << from;
		log(msg.str());
		return;
	}

	std::string url = p.header("location");
	if (url.empty())
	{
		std::stringstream msg;
		msg << "missing location header from " << from;
		log(msg.str());
		return;
	}

	rootdevice d;
	d.url = url;

	std::set<rootdevice>::iterator i = m_devices.find(d);

	if (i == m_devices.end())
	{

		std::string protocol;
		std::string auth;
		char const* error;
		// we don't have this device in our list. Add it
		boost::tie(protocol, auth, d.hostname, d.port, d.path, error)
			= parse_url_components(d.url);

		if (error)
		{
			std::stringstream msg;
			msg << "invalid URL " << d.url << " from " << from << ": " << error;
			log(msg.str());
			return;
		}

		// ignore the auth here. It will be re-parsed
		// by the http connection later

		if (protocol != "http")
		{
			std::stringstream msg;
			msg << "unsupported protocol " << protocol << " from " << from;
			log(msg.str());
			return;
		}

		if (d.port == 0)
		{
			std::stringstream msg;
			msg << "URL with port 0 from " << from;
			log(msg.str());
			return;
		}

		std::stringstream msg;
		msg << "found rootdevice: " << d.url << ". (" << m_devices.size() << ")";
		log(msg.str());

		if (m_devices.size() >= 50)
		{
			std::stringstream msg;
			msg << "too many devices (" << m_devices.size() << "). Ignoring " << d.url;
			log(msg.str());
			return;
		}

		TORRENT_ASSERT(d.mapping.empty());
		for (std::vector<global_mapping_t>::iterator j = m_mappings.begin()
			, end(m_mappings.end()); j != end; ++j)
		{
			mapping_t m;
			m.action = mapping_t::action_add;
			m.local_port = j->local_port;
			m.external_port = j->external_port;
			m.protocol = j->protocol;
			d.mapping.push_back(m);
		}
		boost::tie(i, boost::tuples::ignore) = m_devices.insert(d);
	}


	// since we're using udp, send the query 4 times
	// just to make sure we find all devices
	if (m_retry_count >= 4 && !m_devices.empty())
	{
		error_code ec;
		m_broadcast_timer.cancel(ec);

		for (std::set<rootdevice>::iterator i = m_devices.begin()
			, end(m_devices.end()); i != end; ++i)
		{
			if (i->control_url.empty() && !i->upnp_connection && !i->disabled)
			{
				// we don't have a WANIP or WANPPP url for this device,
				// ask for it
				rootdevice& d = const_cast<rootdevice&>(*i);
				TORRENT_ASSERT(d.magic == 1337);
#ifndef BOOST_NO_EXCEPTIONS
				try
				{
#endif
					std::stringstream msg;
					msg << "connecting to: " << d.url;
					log(msg.str());

					if (d.upnp_connection) d.upnp_connection->close();
					d.upnp_connection.reset(new http_connection(m_io_service
						, m_cc, bind(&upnp::on_upnp_xml, self(), _1, _2
						, boost::ref(d), _5)));
					d.upnp_connection->get(d.url, seconds(30), 1);
#ifndef BOOST_NO_EXCEPTIONS
				}
				catch (std::exception& e)
				{
					(void)e;
					std::stringstream msg;
					msg << "connection failed to: " << d.url << " " << e.what();
					log(msg.str());
					d.disabled = true;
				}
#endif
			}
		}
	}
}

void upnp::post(upnp::rootdevice const& d, std::string const& soap
	, std::string const& soap_action)
{
	TORRENT_ASSERT(d.magic == 1337);
	TORRENT_ASSERT(d.upnp_connection);

	std::stringstream header;
	
	header << "POST " << d.path << " HTTP/1.0\r\n"
		"Host: " << d.hostname << ":" << d.port << "\r\n"
		"Content-Type: text/xml; charset=\"utf-8\"\r\n"
		"Content-Length: " << soap.size() << "\r\n"
		"Soapaction: \"" << d.service_namespace << "#" << soap_action << "\"\r\n\r\n" << soap;

	d.upnp_connection->sendbuffer = header.str();

	std::stringstream msg;
	msg << "sending: " << header.str();
	log(msg.str());
}

void upnp::create_port_mapping(http_connection& c, rootdevice& d, int i)
{
	mutex_t::scoped_lock l(m_mutex);

	TORRENT_ASSERT(d.magic == 1337);

	if (!d.upnp_connection)
	{
		TORRENT_ASSERT(d.disabled);
		std::stringstream msg;
		msg << "mapping " << i << " aborted";
		log(msg.str());
		return;
	}
	
	std::string soap_action = "AddPortMapping";

	std::stringstream soap;
	
	soap << "<?xml version=\"1.0\"?>\n"
		"<s:Envelope xmlns:s=\"http://schemas.xmlsoap.org/soap/envelope/\" "
		"s:encodingStyle=\"http://schemas.xmlsoap.org/soap/encoding/\">"
		"<s:Body><u:" << soap_action << " xmlns:u=\"" << d.service_namespace << "\">";

	error_code ec;
	soap << "<NewRemoteHost></NewRemoteHost>"
		"<NewExternalPort>" << d.mapping[i].external_port << "</NewExternalPort>"
		"<NewProtocol>" << (d.mapping[i].protocol == udp ? "UDP" : "TCP") << "</NewProtocol>"
		"<NewInternalPort>" << d.mapping[i].local_port << "</NewInternalPort>"
		"<NewInternalClient>" << c.socket().local_endpoint(ec).address() << "</NewInternalClient>"
		"<NewEnabled>1</NewEnabled>"
		"<NewPortMappingDescription>" << m_user_agent << "</NewPortMappingDescription>"
		"<NewLeaseDuration>" << d.lease_duration << "</NewLeaseDuration>";
	soap << "</u:" << soap_action << "></s:Body></s:Envelope>";

	post(d, soap.str(), soap_action);
}

void upnp::next(rootdevice& d, int i)
{
	if (i < num_mappings() - 1)
	{
		update_map(d, i + 1);
	}
	else
	{
		std::vector<mapping_t>::iterator i
			= std::find_if(d.mapping.begin(), d.mapping.end()
			, boost::bind(&mapping_t::action, _1) != int(mapping_t::action_none));
		if (i == d.mapping.end()) return;

		update_map(d, i - d.mapping.begin());
	}
}

void upnp::update_map(rootdevice& d, int i)
{
	TORRENT_ASSERT(d.magic == 1337);
	TORRENT_ASSERT(i < int(d.mapping.size()));
	TORRENT_ASSERT(d.mapping.size() == m_mappings.size());

	if (d.upnp_connection) return;

	mapping_t& m = d.mapping[i];

	if (m.action == mapping_t::action_none
		|| m.protocol == none)
	{
		std::stringstream msg;
		msg << "mapping " << i << " does not need updating, skipping";
		log(msg.str());
		m.action = mapping_t::action_none;
		next(d, i);
		return;
	}

	TORRENT_ASSERT(!d.upnp_connection);
	TORRENT_ASSERT(d.service_namespace);

	std::stringstream msg;
	msg << "connecting to " << d.hostname;
	log(msg.str());
	if (m.action == mapping_t::action_add)
	{
		if (m.failcount > 5)
		{
			m.action = mapping_t::action_none;
			// giving up
			next(d, i);
			return;
		}

		if (d.upnp_connection) d.upnp_connection->close();
		d.upnp_connection.reset(new http_connection(m_io_service
			, m_cc, bind(&upnp::on_upnp_map_response, self(), _1, _2
			, boost::ref(d), i, _5), true
			, bind(&upnp::create_port_mapping, self(), _1, boost::ref(d), i)));

		d.upnp_connection->start(d.hostname, to_string(d.port).elems
			, seconds(10), 1);
	}
	else if (m.action == mapping_t::action_delete)
	{
		if (d.upnp_connection) d.upnp_connection->close();
		d.upnp_connection.reset(new http_connection(m_io_service
			, m_cc, bind(&upnp::on_upnp_unmap_response, self(), _1, _2
			, boost::ref(d), i, _5), true
			, bind(&upnp::delete_port_mapping, self(), boost::ref(d), i)));
		d.upnp_connection->start(d.hostname, to_string(d.port).elems
			, seconds(10), 1);
	}

	m.action = mapping_t::action_none;
}

void upnp::delete_port_mapping(rootdevice& d, int i)
{
	mutex_t::scoped_lock l(m_mutex);

	TORRENT_ASSERT(d.magic == 1337);

	if (!d.upnp_connection)
	{
		TORRENT_ASSERT(d.disabled);
		std::stringstream msg;
		msg << "unmapping " << i << " aborted";
		log(msg.str());
		return;
	}

	std::stringstream soap;
	
	std::string soap_action = "DeletePortMapping";

	soap << "<?xml version=\"1.0\"?>\n"
		"<s:Envelope xmlns:s=\"http://schemas.xmlsoap.org/soap/envelope/\" "
		"s:encodingStyle=\"http://schemas.xmlsoap.org/soap/encoding/\">"
		"<s:Body><u:" << soap_action << " xmlns:u=\"" << d.service_namespace << "\">";

	soap << "<NewRemoteHost></NewRemoteHost>"
		"<NewExternalPort>" << d.mapping[i].external_port << "</NewExternalPort>"
		"<NewProtocol>" << (d.mapping[i].protocol == udp ? "UDP" : "TCP") << "</NewProtocol>";
	soap << "</u:" << soap_action << "></s:Body></s:Envelope>";
	
	post(d, soap.str(), soap_action);
}

namespace
{
	char tolower(char c)
	{
		if (c >= 'A' && c <= 'Z') return c + ('a' - 'A');
		return c;
	}

	void copy_tolower(std::string& dst, char const* src)
	{
		dst.clear();
		while (*src) dst.push_back(tolower(*src++));
	}
	
	bool string_equal_nocase(char const* lhs, char const* rhs)
	{
		while (tolower(*lhs) == tolower(*rhs))
		{
			if (*lhs == 0) return true;
			++lhs;
			++rhs;
		}
		return false;
	}
}

struct parse_state
{
	parse_state(): in_service(false) {}
	void reset(char const* st)
	{
		in_service = false;
		service_type = st;
		tag_stack.clear();
		control_url.clear();
		model.clear();
		url_base.clear();
	}
	bool in_service;
	std::list<std::string> tag_stack;
	std::string control_url;
	char const* service_type;
	std::string model;
	std::string url_base;
	bool top_tags(const char* str1, const char* str2)
	{
		std::list<std::string>::reverse_iterator i = tag_stack.rbegin();
		if (i == tag_stack.rend()) return false;
		if (!string_equal_nocase(i->c_str(), str2)) return false;
		++i;
		if (i == tag_stack.rend()) return false;
		if (!string_equal_nocase(i->c_str(), str1)) return false;
		return true;
	}
};

void find_control_url(int type, char const* string, parse_state& state)
{
	if (type == xml_start_tag)
	{
		std::string tag;
		copy_tolower(tag, string);
		state.tag_stack.push_back(tag);
//		std::copy(state.tag_stack.begin(), state.tag_stack.end(), std::ostream_iterator<std::string>(std::cout, " "));
//		std::cout << std::endl;
	}
	else if (type == xml_end_tag)
	{
		if (!state.tag_stack.empty())
		{
			if (state.in_service && state.tag_stack.back() == "service")
				state.in_service = false;
			state.tag_stack.pop_back();
		}
	}
	else if (type == xml_string)
	{
		if (state.tag_stack.empty()) return;
//		std::cout << " " << string << std::endl;
		if (!state.in_service && state.top_tags("service", "servicetype"))
		{
			if (string_equal_nocase(string, state.service_type))
				state.in_service = true;
		}
		else if (state.in_service && state.top_tags("service", "controlurl"))
		{
			state.control_url = string;
		}
		else if (state.model.empty() && state.top_tags("device", "modelname"))
		{
			state.model = string;
		}
		else if (state.tag_stack.back() == "urlbase")
		{
			state.url_base = string;
		}
	}
}

void upnp::on_upnp_xml(error_code const& e
	, libtorrent::http_parser const& p, rootdevice& d
	, http_connection& c)
{
	mutex_t::scoped_lock l(m_mutex);

	TORRENT_ASSERT(d.magic == 1337);
	if (d.upnp_connection && d.upnp_connection.get() == &c)
	{
		d.upnp_connection->close();
		d.upnp_connection.reset();
	}

	if (e && e != asio::error::eof)
	{
		std::stringstream msg;
		msg << "error while fetching control url from " << d.url << ": " << e.message();
		log(msg.str());
		d.disabled = true;
		return;
	}

	if (!p.header_finished())
	{
		std::stringstream msg;
		msg << "error while fetching control url from " << d.url << ": incomplete HTTP message";
		log(msg.str());
		d.disabled = true;
		return;
	}

	if (p.status_code() != 200)
	{
		std::stringstream msg;
		msg << "error while fetching control url from " << d.url << ": " << p.message();
		log(msg.str());
		d.disabled = true;
		return;
	}

	parse_state s;
	s.reset("urn:schemas-upnp-org:service:WANIPConnection:1");
	xml_parse((char*)p.get_body().begin, (char*)p.get_body().end
		, bind(&find_control_url, _1, _2, boost::ref(s)));
	if (!s.control_url.empty())
	{
		d.service_namespace = s.service_type;
		if (!s.model.empty()) m_model = s.model;
	}
	else
	{
		// we didn't find the WAN IP connection, look for
		// a PPP connection
		s.reset("urn:schemas-upnp-org:service:WANPPPConnection:1");
		xml_parse((char*)p.get_body().begin, (char*)p.get_body().end
			, bind(&find_control_url, _1, _2, boost::ref(s)));
		if (!s.control_url.empty())
		{
			d.service_namespace = s.service_type;
			if (!s.model.empty()) m_model = s.model;
		}
		else
		{
			std::stringstream msg;
			msg << "Could not find a port mapping interface in response from " << d.url;
			log(msg.str());
			d.disabled = true;
			return;
		}
	}
	
	if (!s.url_base.empty())
	{
		// avoid double slashes in path
		if (s.url_base[s.url_base.size()-1] == '/'
			&& !s.control_url.empty()
			&& s.control_url[0] == '/')
			s.url_base.erase(s.url_base.end()-1);
		d.control_url = s.url_base + s.control_url;
	}
	else d.control_url = s.control_url;

	std::string protocol;
	std::string auth;
	char const* error;
	if (!d.control_url.empty() && d.control_url[0] == '/')
	{
		boost::tie(protocol, auth, d.hostname, d.port, d.path, error)
			= parse_url_components(d.url);
		d.control_url = protocol + "://" + d.hostname + ":"
			+ to_string(d.port).elems + s.control_url;
	}

	std::stringstream msg;
	msg << "found control URL: " << d.control_url << " namespace: "
		<< d.service_namespace << " urlbase: " << s.url_base << " in response from " << d.url;
	log(msg.str());

	boost::tie(protocol, auth, d.hostname, d.port, d.path, error)
		= parse_url_components(d.control_url);

	if (error)
	{
		std::stringstream msg;
		msg << "failed to parse URL '" << d.control_url << "': " << error;
		log(msg.str());
		d.disabled = true;
		return;
	}

	if (num_mappings() > 0) update_map(d, 0);
}

void upnp::disable(char const* msg)
{
	m_disabled = true;

	// kill all mappings
	for (std::vector<global_mapping_t>::iterator i = m_mappings.begin()
		, end(m_mappings.end()); i != end; ++i)
	{
		if (i->protocol == none) continue;
		i->protocol = none;
		m_callback(i - m_mappings.begin(), 0, msg);
	}
	
	m_devices.clear();
	error_code ec;
	m_broadcast_timer.cancel(ec);
	m_refresh_timer.cancel(ec);
	m_socket.close();
}

namespace
{
	struct error_code_parse_state
	{
		error_code_parse_state(): in_error_code(false), exit(false), error_code(-1) {}
		bool in_error_code;
		bool exit;
		int error_code;
	};
	
	void find_error_code(int type, char const* string, error_code_parse_state& state)
	{
		if (state.exit) return;
		if (type == xml_start_tag && !std::strcmp("errorCode", string))
		{
			state.in_error_code = true;
		}
		else if (type == xml_string && state.in_error_code)
		{
			state.error_code = std::atoi(string);
			state.exit = true;
		}
	}
}

namespace
{
	struct error_code_t
	{
		int code;
		char const* msg;
	};
	
	error_code_t error_codes[] =
	{
		{402, "Invalid Arguments"}
		, {501, "Action Failed"}
		, {714, "The specified value does not exist in the array"}
		, {715, "The source IP address cannot be wild-carded"}
		, {716, "The external port cannot be wild-carded"}
		, {718, "The port mapping entry specified conflicts with "
			"a mapping assigned previously to another client"}
		, {724, "Internal and External port values must be the same"}
		, {725, "The NAT implementation only supports permanent "
			"lease times on port mappings"}
		, {726, "RemoteHost must be a wildcard and cannot be a "
			"specific IP address or DNS name"}
		, {727, "ExternalPort must be a wildcard and cannot be a specific port "}
	};

}

void upnp::on_upnp_map_response(error_code const& e
	, libtorrent::http_parser const& p, rootdevice& d, int mapping
	, http_connection& c)
{
	mutex_t::scoped_lock l(m_mutex);

	TORRENT_ASSERT(d.magic == 1337);
	if (d.upnp_connection && d.upnp_connection.get() == &c)
	{
		d.upnp_connection->close();
		d.upnp_connection.reset();
	}

	if (e && e != asio::error::eof)
	{
		std::stringstream msg;
		msg << "error while adding port map: " << e.message();
		log(msg.str());
		d.disabled = true;
		return;
	}
	
	if (m_closing) return;
	
//	 error code response may look like this:
//	<s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/"
//		s:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/">
//	 <s:Body>
//	  <s:Fault>
//		<faultcode>s:Client</faultcode>
//		<faultstring>UPnPError</faultstring>
//		<detail>
//		 <UPnPErrorxmlns="urn:schemas-upnp-org:control-1-0">
//		  <errorCode>402</errorCode>
//		  <errorDescription>Invalid Args</errorDescription>
//		 </UPnPError>
//		</detail>
//	  </s:Fault>
//	 </s:Body>
//	</s:Envelope>

	if (!p.header_finished())
	{
		std::stringstream msg;
		msg << "error while adding port map: incomplete http message";
		log(msg.str());
		next(d, mapping);
		return;
	}

	// We don't want to ignore responses with return codes other than 200
	// since those might contain valid UPnP error codes

	error_code_parse_state s;
	xml_parse((char*)p.get_body().begin, (char*)p.get_body().end
		, bind(&find_error_code, _1, _2, boost::ref(s)));

	if (s.error_code != -1)
	{
		std::stringstream msg;
		msg << "error while adding port map, code: " << s.error_code;
		log(msg.str());
	}
	
	mapping_t& m = d.mapping[mapping];

	if (s.error_code == 725)
	{
		// only permanent leases supported
		d.lease_duration = 0;
		m.action = mapping_t::action_add;
		++m.failcount;
		update_map(d, mapping);
		return;
	}
	else if (s.error_code == 718 || s.error_code == 727)
	{
		if (m.external_port != 0)
		{
			// conflict in mapping, set port to wildcard
			// and let the router decide
			m.external_port = 0;
			m.action = mapping_t::action_add;
			++m.failcount;
			update_map(d, mapping);
			return;
		}
		return_error(mapping, s.error_code);
	}
	else if (s.error_code == 716)
	{
		// The external port cannot be wildcarder
		// pick a random port
		m.external_port = 40000 + (std::rand() % 10000);
		m.action = mapping_t::action_add;
		++m.failcount;
		update_map(d, mapping);
		return;
	}
	else if (s.error_code != -1)
	{
		return_error(mapping, s.error_code);
	}

	std::stringstream msg;
	msg << "map response: " << std::string(p.get_body().begin, p.get_body().end);
	log(msg.str());

	if (s.error_code == -1)
	{
		m_callback(mapping, m.external_port, "");
		if (d.lease_duration > 0)
		{
			m.expires = time_now()
				+ seconds(int(d.lease_duration * 0.75f));
			ptime next_expire = m_refresh_timer.expires_at();
			if (next_expire < time_now()
				|| next_expire > m.expires)
			{
				error_code ec;
				m_refresh_timer.expires_at(m.expires, ec);
				m_refresh_timer.async_wait(bind(&upnp::on_expire, self(), _1));
			}
		}
		else
		{
			m.expires = max_time();
		}
		m.failcount = 0;
	}

	next(d, mapping);
}

void upnp::return_error(int mapping, int code)
{
	int num_errors = sizeof(error_codes) / sizeof(error_codes[0]);
	error_code_t* end = error_codes + num_errors;
	error_code_t tmp = {code, 0};
	error_code_t* e = std::lower_bound(error_codes, end, tmp
		, bind(&error_code_t::code, _1) < bind(&error_code_t::code, _2));
	std::string error_string = "UPnP mapping error ";
	error_string += to_string(code).elems;
	if (e != end && e->code == code)
	{
		error_string += ": ";
		error_string += e->msg;
	}
	m_callback(mapping, 0, error_string);
}

void upnp::on_upnp_unmap_response(error_code const& e
	, libtorrent::http_parser const& p, rootdevice& d, int mapping
	, http_connection& c)
{
	mutex_t::scoped_lock l(m_mutex);

	TORRENT_ASSERT(d.magic == 1337);
	if (d.upnp_connection && d.upnp_connection.get() == &c)
	{
		d.upnp_connection->close();
		d.upnp_connection.reset();
	}

	if (e && e != asio::error::eof)
	{
		std::stringstream msg;
		msg << "error while deleting portmap: " << e.message();
		log(msg.str());
	}
	else if (!p.header_finished())
	{
		std::stringstream msg;
		msg << "error while deleting portmap: incomplete http message";
		log(msg.str());
	}
	else if (p.status_code() != 200)
	{
		std::stringstream msg;
		msg << "error while deleting portmap: " << p.message();
		log(msg.str());
	}
	else
	{
		std::stringstream msg;
		msg << "unmap response: " << std::string(p.get_body().begin, p.get_body().end);
		log(msg.str());
	}

	d.mapping[mapping].protocol = none;

	next(d, mapping);
}

void upnp::on_expire(error_code const& e)
{
	if (e) return;

	ptime now = time_now();
	ptime next_expire = max_time();

	mutex_t::scoped_lock l(m_mutex);

	for (std::set<rootdevice>::iterator i = m_devices.begin()
		, end(m_devices.end()); i != end; ++i)
	{
		rootdevice& d = const_cast<rootdevice&>(*i);
		TORRENT_ASSERT(d.magic == 1337);
		for (int m = 0; m < num_mappings(); ++m)
		{
			if (d.mapping[m].expires != max_time())
				continue;

			if (d.mapping[m].expires < now)
			{
				d.mapping[m].expires = max_time();
				update_map(d, m);
			}
			else if (d.mapping[m].expires < next_expire)
			{
				next_expire = d.mapping[m].expires;
			}
		}
	}
	if (next_expire != max_time())
	{
		error_code ec;
		m_refresh_timer.expires_at(next_expire, ec);
		m_refresh_timer.async_wait(bind(&upnp::on_expire, self(), _1));
	}
}

void upnp::close()
{
	mutex_t::scoped_lock l(m_mutex);

	error_code ec;
	m_refresh_timer.cancel(ec);
	m_broadcast_timer.cancel(ec);
	m_closing = true;
	m_socket.close();

	for (std::set<rootdevice>::iterator i = m_devices.begin()
		, end(m_devices.end()); i != end; ++i)
	{
		rootdevice& d = const_cast<rootdevice&>(*i);
		TORRENT_ASSERT(d.magic == 1337);
		if (d.control_url.empty()) continue;
		for (std::vector<mapping_t>::iterator j = d.mapping.begin()
			, end(d.mapping.end()); j != end; ++j)
		{
			if (j->protocol == none) continue;
			if (j->action == mapping_t::action_add)
			{
				j->action = mapping_t::action_none;
				continue;
			}
			j->action = mapping_t::action_delete;
			m_mappings[j - d.mapping.begin()].protocol = none;
		}
		if (num_mappings() > 0) update_map(d, 0);
	}
}