/*

Copyright (c) 2007-2018, 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/config.hpp"
#include "libtorrent/socket.hpp"
#include "libtorrent/socket_io.hpp"
#include "libtorrent/upnp.hpp"
#include "libtorrent/io.hpp"
#include "libtorrent/parse_url.hpp"
#include "libtorrent/xml_parse.hpp"
#include "libtorrent/random.hpp"
#include "libtorrent/aux_/time.hpp" // for aux::time_now()
#include "libtorrent/aux_/escape_string.hpp" // for convert_from_native
#include "libtorrent/http_connection.hpp"

#if defined TORRENT_ASIO_DEBUGGING
#include "libtorrent/debug.hpp"
#endif
#include "libtorrent/aux_/numeric_cast.hpp"

#include "libtorrent/aux_/disable_warnings_push.hpp"
#include <boost/asio/ip/host_name.hpp>
#include <boost/asio/ip/multicast.hpp>
#ifdef TORRENT_USE_OPENSSL
#include <boost/asio/ssl/context.hpp>
#endif
#include "libtorrent/aux_/disable_warnings_pop.hpp"

#include <cstdlib>
#include <cstdio> // for snprintf
#include <cstdarg>
#include <functional>

using namespace std::placeholders;

namespace libtorrent {

using namespace aux;

// due to the recursive nature of update_map, it's necessary to
// limit the internal list of global mappings to a small size
// this can be changed once the entire UPnP code is refactored
constexpr std::size_t max_global_mappings = 50;

namespace upnp_errors
{
	boost::system::error_code make_error_code(error_code_enum e)
	{ return {e, upnp_category()}; }

} // upnp_errors namespace

static error_code ignore_error;

upnp::rootdevice::rootdevice() = default;
#if TORRENT_USE_ASSERTS
upnp::rootdevice::~rootdevice()
{
	TORRENT_ASSERT(magic == 1337);
	magic = 0;
}
#else
upnp::rootdevice::~rootdevice() = default;
#endif

upnp::rootdevice::rootdevice(rootdevice const&) = default;
upnp::rootdevice& upnp::rootdevice::operator=(rootdevice const&) = default;
upnp::rootdevice::rootdevice(rootdevice&&) = default;
upnp::rootdevice& upnp::rootdevice::operator=(rootdevice&&) = default;

// TODO: 3 bind the broadcast socket. it would probably have to be changed to a vector of interfaces to
// bind to, since the broadcast socket opens one socket per local
// interface by default
upnp::upnp(io_service& ios
	, aux::session_settings const& settings
	, aux::portmap_callback& cb
	, address_v4 const& listen_address
	, address_v4 const& netmask
	, std::string listen_device)
	: m_settings(settings)
	, m_callback(cb)
	, m_io_service(ios)
	, m_resolver(ios)
	, m_multicast_socket(ios)
	, m_unicast_socket(ios)
	, m_broadcast_timer(ios)
	, m_refresh_timer(ios)
	, m_map_timer(ios)
	, m_listen_address(listen_address)
	, m_netmask(netmask)
	, m_device(std::move(listen_device))
#ifdef TORRENT_USE_OPENSSL
	, m_ssl_ctx(ssl::context::sslv23_client)
#endif
{
#ifdef TORRENT_USE_OPENSSL
	m_ssl_ctx.set_verify_mode(ssl::context::verify_none);
#endif
}

void upnp::start()
{
	TORRENT_ASSERT(is_single_thread());

	error_code ec;
	open_multicast_socket(m_multicast_socket, ec);
#ifndef TORRENT_DISABLE_LOGGING
	if (ec && should_log())
	{
		log("failed to open multicast socket: \"%s\""
			, convert_from_native(ec.message()).c_str());
		m_disabled = true;
		return;
	}
#endif

	open_unicast_socket(m_unicast_socket, ec);
#ifndef TORRENT_DISABLE_LOGGING
	if (ec && should_log())
	{
		log("failed to open unicast socket: \"%s\""
			, convert_from_native(ec.message()).c_str());
		m_disabled = true;
		return;
	}
#endif

	m_mappings.reserve(2);

	discover_device_impl();
}

namespace {
	address_v4 const ssdp_multicast_addr = make_address_v4("239.255.255.250");
	int const ssdp_port = 1900;

}

void upnp::open_multicast_socket(udp::socket& s, error_code& ec)
{
	using namespace boost::asio::ip::multicast;
	s.open(udp::v4(), ec);
	if (ec) return;
	s.set_option(udp::socket::reuse_address(true), ec);
	if (ec) return;
	s.bind(udp::endpoint(m_listen_address, ssdp_port), ec);
	if (ec) return;
	s.set_option(join_group(ssdp_multicast_addr), ec);
	if (ec) return;
	s.set_option(hops(255), ec);
	if (ec) return;
	s.set_option(enable_loopback(true), ec);
	if (ec) return;
	s.set_option(outbound_interface(m_listen_address), ec);
	if (ec) return;

	ADD_OUTSTANDING_ASYNC("upnp::on_reply");
	s.async_receive(boost::asio::null_buffers{}
		, std::bind(&upnp::on_reply, self(), std::ref(s), _1));
}

void upnp::open_unicast_socket(udp::socket& s, error_code& ec)
{
	s.open(udp::v4(), ec);
	if (ec) return;
	s.bind(udp::endpoint(m_listen_address, 0), ec);
	if (ec) return;

	ADD_OUTSTANDING_ASYNC("upnp::on_reply");
	s.async_receive(boost::asio::null_buffers{}
		, std::bind(&upnp::on_reply, self(), std::ref(s), _1));
}

upnp::~upnp() = default;

#ifndef TORRENT_DISABLE_LOGGING
bool upnp::should_log() const
{
	return m_callback.should_log_portmap(portmap_transport::upnp);
}

TORRENT_FORMAT(2,3)
void upnp::log(char const* fmt, ...) const
{
	TORRENT_ASSERT(is_single_thread());
	if (!should_log()) return;
	va_list v;
	va_start(v, fmt);
	char msg[1024];
	std::vsnprintf(msg, sizeof(msg), fmt, v);
	va_end(v);
	m_callback.log_portmap(portmap_transport::upnp, msg);
}
#endif

void upnp::discover_device_impl()
{
	TORRENT_ASSERT(is_single_thread());
	static 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

	error_code mcast_ec;
	error_code ucast_ec;
	m_multicast_socket.send_to(boost::asio::buffer(msearch, sizeof(msearch) - 1)
		, udp::endpoint(ssdp_multicast_addr, ssdp_port), 0, mcast_ec);
	m_unicast_socket.send_to(boost::asio::buffer(msearch, sizeof(msearch) - 1)
		, udp::endpoint(ssdp_multicast_addr, ssdp_port), 0, ucast_ec);

	if (mcast_ec && ucast_ec)
	{
#ifndef TORRENT_DISABLE_LOGGING
		if (should_log())
		{
			log("multicast send failed: \"%s\" and \"%s\". Aborting."
				, convert_from_native(mcast_ec.message()).c_str()
				, convert_from_native(ucast_ec.message()).c_str());
		}
#endif
		disable(mcast_ec);
		return;
	}

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

#ifndef TORRENT_DISABLE_LOGGING
	log("broadcasting search for rootdevice");
#endif
}

// returns a reference to a mapping or -1 on failure
port_mapping_t upnp::add_mapping(portmap_protocol const p, int const external_port
	, tcp::endpoint const local_ep)
{
	TORRENT_ASSERT(is_single_thread());
	// external port 0 means _every_ port
	TORRENT_ASSERT(external_port != 0);

#ifndef TORRENT_DISABLE_LOGGING
	if (should_log())
	{
		log("adding port map: [ protocol: %s ext_port: %d "
			"local_ep: %s ] %s", (p == portmap_protocol::tcp?"tcp":"udp")
			, external_port
			, print_endpoint(local_ep).c_str(), m_disabled ? "DISABLED": "");
	}
#endif
	if (m_disabled) return port_mapping_t{-1};

	auto mapping_it = std::find_if(m_mappings.begin(), m_mappings.end()
		, [](global_mapping_t const& m) { return m.protocol == portmap_protocol::none; });

	if (mapping_it == m_mappings.end())
	{
		TORRENT_ASSERT(m_mappings.size() <= max_global_mappings);
		if (m_mappings.size() >= max_global_mappings)
		{
#ifndef TORRENT_DISABLE_LOGGING
			log("too many mappings registered");
#endif
			return port_mapping_t{-1};
		}
		m_mappings.push_back(global_mapping_t());
		mapping_it = m_mappings.end() - 1;
	}

	mapping_it->protocol = p;
	mapping_it->external_port = external_port;
	mapping_it->local_ep = local_ep;

	port_mapping_t const mapping_index{static_cast<int>(mapping_it - m_mappings.begin())};

	for (auto const& dev : m_devices)
	{
		rootdevice& d = const_cast<rootdevice&>(dev);
		TORRENT_ASSERT(d.magic == 1337);
		if (d.disabled) continue;

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

		m.act = portmap_action::add;
		m.protocol = p;
		m.external_port = external_port;
		m.local_ep = local_ep;

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

	return port_mapping_t{mapping_index};
}

void upnp::delete_mapping(port_mapping_t const mapping)
{
	TORRENT_ASSERT(is_single_thread());

	if (mapping >= m_mappings.end_index()) return;

	global_mapping_t const& m = m_mappings[mapping];

#ifndef TORRENT_DISABLE_LOGGING
	if (should_log())
	{
		log("deleting port map: [ protocol: %s ext_port: %u "
			"local_ep: %s ]", (m.protocol == portmap_protocol::tcp?"tcp":"udp"), m.external_port
			, print_endpoint(m.local_ep).c_str());
	}
#endif

	if (m.protocol == portmap_protocol::none) return;

	for (auto const& dev : m_devices)
	{
		rootdevice& d = const_cast<rootdevice&>(dev);
		TORRENT_ASSERT(d.magic == 1337);
		if (d.disabled) continue;

		TORRENT_ASSERT(mapping < d.mapping.end_index());
		d.mapping[mapping].act = portmap_action::del;

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

bool upnp::get_mapping(port_mapping_t const index
	, tcp::endpoint& local_ep
	, int& external_port
	, portmap_protocol& protocol) const
{
	TORRENT_ASSERT(is_single_thread());
	TORRENT_ASSERT(index < m_mappings.end_index() && index >= port_mapping_t{0});
	if (index >= m_mappings.end_index() || index < port_mapping_t{0}) return false;
	global_mapping_t const& m = m_mappings[index];
	if (m.protocol == portmap_protocol::none) return false;
	local_ep = m.local_ep;
	external_port = m.external_port;
	protocol = m.protocol;
	return true;
}

void upnp::resend_request(error_code const& ec)
{
	TORRENT_ASSERT(is_single_thread());
	COMPLETE_ASYNC("upnp::resend_request");
	if (ec) return;

	std::shared_ptr<upnp> me(self());

	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(errors::no_router);
		return;
	}

	for (auto const& dev : m_devices)
	{
		if (!dev.control_url.empty()
			|| dev.upnp_connection
			|| dev.disabled)
		{
			continue;
		}

		// we don't have a WANIP or WANPPP url for this device,
		// ask for it
		connect(const_cast<rootdevice&>(dev));
	}
}

void upnp::connect(rootdevice& d)
{
	TORRENT_ASSERT(d.magic == 1337);
	TORRENT_TRY
	{
#ifndef TORRENT_DISABLE_LOGGING
		log("connecting to: %s", d.url.c_str());
#endif
		if (d.upnp_connection) d.upnp_connection->close();
		d.upnp_connection = std::make_shared<http_connection>(m_io_service
			, m_resolver
			, std::bind(&upnp::on_upnp_xml, self(), _1, _2
				, std::ref(d), _4), true, default_max_bottled_buffer_size
			, http_connect_handler()
			, http_filter_handler()
#ifdef TORRENT_USE_OPENSSL
			, &m_ssl_ctx
#endif
			);
		d.upnp_connection->get(d.url, seconds(30), 1);
	}
	TORRENT_CATCH (std::exception const& exc)
	{
		TORRENT_DECLARE_DUMMY(std::exception, exc);
		TORRENT_UNUSED(exc);
#ifndef TORRENT_DISABLE_LOGGING
		log("connection failed to: %s %s", d.url.c_str(), exc.what());
#endif
		d.disabled = true;
	}
}

void upnp::on_reply(udp::socket& s, error_code const& ec)
{
	TORRENT_ASSERT(is_single_thread());
	COMPLETE_ASYNC("upnp::on_reply");

	if (ec == boost::asio::error::operation_aborted) return;
	if (m_closing) return;

	std::shared_ptr<upnp> me(self());

	std::array<char, 1500> buffer{};
	udp::endpoint from;
	error_code err;
	int const len = static_cast<int>(s.receive_from(boost::asio::buffer(buffer)
		, from, 0, err));

	// 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

*/

	ADD_OUTSTANDING_ASYNC("upnp::on_reply");
	s.async_receive(boost::asio::null_buffers{}
		, std::bind(&upnp::on_reply, self(), std::ref(s), _1));

	if (err) return;

	if (!match_addr_mask(m_listen_address, from.address(), m_netmask))
	{
#ifndef TORRENT_DISABLE_LOGGING
		if (should_log())
		{
			log("ignoring response from: %s. IP is not on local network. (addr: %s mask: %s)"
				, print_endpoint(from).c_str()
				, m_listen_address.to_string().c_str()
				, m_netmask.to_string().c_str());
		}
#endif
		return;
	}

	http_parser p;
	bool error = false;
	p.incoming({buffer.data(), len}, error);
	if (error)
	{
#ifndef TORRENT_DISABLE_LOGGING
		if (should_log())
		{
			log("received malformed HTTP from: %s"
				, print_endpoint(from).c_str());
		}
#endif
		return;
	}

	if (p.status_code() != 200 && p.method() != "notify")
	{
#ifndef TORRENT_DISABLE_LOGGING
		if (should_log())
		{
			if (p.method().empty())
			{
				log("HTTP status %u from %s"
					, p.status_code(), print_endpoint(from).c_str());
			}
			else
			{
				log("HTTP method %s from %s"
					, p.method().c_str(), print_endpoint(from).c_str());
			}
		}
#endif
		return;
	}

	if (!p.header_finished())
	{
#ifndef TORRENT_DISABLE_LOGGING
		if (should_log())
		{
			log("incomplete HTTP packet from %s"
				, print_endpoint(from).c_str());
		}
#endif
		return;
	}

	std::string url = p.header("location");
	if (url.empty())
	{
#ifndef TORRENT_DISABLE_LOGGING
		if (should_log())
		{
			log("missing location header from %s"
				, print_endpoint(from).c_str());
		}
#endif
		return;
	}

	rootdevice d;
	d.url = url;
	d.lease_duration = m_settings.get_int(settings_pack::upnp_lease_duration);

	auto i = m_devices.find(d);

	if (i == m_devices.end())
	{
		std::string protocol;
		std::string auth;
		// we don't have this device in our list. Add it
		std::tie(protocol, auth, d.hostname, d.port, d.path)
			= parse_url_components(d.url, err);
		if (d.port == -1) d.port = protocol == "http" ? 80 : 443;

		if (err)
		{
#ifndef TORRENT_DISABLE_LOGGING
			if (should_log())
			{
				log("invalid URL %s from %s: %s"
					, d.url.c_str(), print_endpoint(from).c_str(), convert_from_native(err.message()).c_str());
			}
#endif
			return;
		}

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

		if (protocol != "http")
		{
#ifndef TORRENT_DISABLE_LOGGING
			if (should_log())
			{
				log("unsupported protocol %s from %s"
					, protocol.c_str(), print_endpoint(from).c_str());
			}
#endif
			return;
		}

		if (d.port == 0)
		{
#ifndef TORRENT_DISABLE_LOGGING
			if (should_log())
			{
				log("URL with port 0 from %s", print_endpoint(from).c_str());
			}
#endif
			return;
		}

#ifndef TORRENT_DISABLE_LOGGING
		if (should_log())
		{
			log("found rootdevice: %s (%d)"
				, d.url.c_str(), int(m_devices.size()));
		}
#endif

		if (m_devices.size() >= 50)
		{
#ifndef TORRENT_DISABLE_LOGGING
			if (should_log())
			{
				log("too many rootdevices: (%d). Ignoring %s"
					, int(m_devices.size()), d.url.c_str());
			}
#endif
			return;
		}

		TORRENT_ASSERT(d.mapping.empty());
		for (auto const& j : m_mappings)
		{
			mapping_t m;
			m.act = portmap_action::add;
			m.local_ep = j.local_ep;
			m.external_port = j.external_port;
			m.protocol = j.protocol;
			d.mapping.push_back(m);
		}
		std::tie(i, std::ignore) = m_devices.insert(d);
	}


	// iterate over the devices we know and connect and issue the mappings
	try_map_upnp();

	// check back in a little bit to see if we have seen any
	// devices at one of our default routes. If not, we want to override
	// ignoring them and use them instead (better than not working).
	m_map_timer.expires_from_now(seconds(1), err);
	ADD_OUTSTANDING_ASYNC("upnp::map_timer");
	m_map_timer.async_wait(std::bind(&upnp::map_timer, self(), _1));
}

void upnp::map_timer(error_code const& ec)
{
	TORRENT_ASSERT(is_single_thread());
	COMPLETE_ASYNC("upnp::map_timer");
	if (ec) return;
	if (m_closing) return;

	try_map_upnp();
}

void upnp::try_map_upnp()
{
	TORRENT_ASSERT(is_single_thread());
	if (m_devices.empty()) return;

	for (auto 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
			connect(const_cast<rootdevice&>(*i));
		}
	}
}

void upnp::post(upnp::rootdevice const& d, char const* soap
	, char const* soap_action)
{
	TORRENT_ASSERT(is_single_thread());
	TORRENT_ASSERT(d.magic == 1337);
	TORRENT_ASSERT(d.upnp_connection);
	TORRENT_ASSERT(!d.disabled);

	char header[2048];
	std::snprintf(header, sizeof(header), "POST %s HTTP/1.1\r\n"
		"Host: %s:%d\r\n"
		"Content-Type: text/xml; charset=\"utf-8\"\r\n"
		"Content-Length: %d\r\n"
		"Soapaction: \"%s#%s\"\r\n\r\n"
		"%s"
		, d.path.c_str(), d.hostname.c_str(), d.port
		, int(strlen(soap)), d.service_namespace.c_str(), soap_action
		, soap);

	d.upnp_connection->m_sendbuffer = header;

#ifndef TORRENT_DISABLE_LOGGING
	log("sending: %s", header);
#endif
}

void upnp::create_port_mapping(http_connection& c, rootdevice& d
	, port_mapping_t const i)
{
	TORRENT_ASSERT(is_single_thread());

	TORRENT_ASSERT(d.magic == 1337);

	if (!d.upnp_connection)
	{
		TORRENT_ASSERT(d.disabled);
#ifndef TORRENT_DISABLE_LOGGING
		log("mapping %u aborted", static_cast<int>(i));
#endif
		return;
	}

	char const* soap_action = "AddPortMapping";

	error_code ec;
	std::string local_endpoint = print_address(c.socket().local_endpoint(ec).address());

	char soap[1024];
	std::snprintf(soap, sizeof(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:%s xmlns:u=\"%s\">"
		"<NewRemoteHost></NewRemoteHost>"
		"<NewExternalPort>%u</NewExternalPort>"
		"<NewProtocol>%s</NewProtocol>"
		"<NewInternalPort>%u</NewInternalPort>"
		"<NewInternalClient>%s</NewInternalClient>"
		"<NewEnabled>1</NewEnabled>"
		"<NewPortMappingDescription>%s</NewPortMappingDescription>"
		"<NewLeaseDuration>%d</NewLeaseDuration>"
		"</u:%s></s:Body></s:Envelope>"
		, soap_action, d.service_namespace.c_str(), d.mapping[i].external_port
		, to_string(d.mapping[i].protocol)
		, d.mapping[i].local_ep.port()
		, local_endpoint.c_str()
		, m_settings.get_bool(settings_pack::anonymous_mode)
			? "" : m_settings.get_str(settings_pack::user_agent).c_str()
		, d.lease_duration, soap_action);

	post(d, soap, soap_action);
}

void upnp::next(rootdevice& d, port_mapping_t const i)
{
	TORRENT_ASSERT(is_single_thread());
	TORRENT_ASSERT(!d.disabled);
	if (i < prev(m_mappings.end_index()))
	{
		update_map(d, lt::next(i));
	}
	else
	{
		auto const j = std::find_if(d.mapping.begin(), d.mapping.end()
			, [](mapping_t const& m) { return m.act != portmap_action::none; });
		if (j == d.mapping.end()) return;

		update_map(d, port_mapping_t{static_cast<int>(j - d.mapping.begin())});
	}
}

void upnp::update_map(rootdevice& d, port_mapping_t const i)
{
	TORRENT_ASSERT(is_single_thread());
	TORRENT_ASSERT(d.magic == 1337);
	TORRENT_ASSERT(i < d.mapping.end_index());
	TORRENT_ASSERT(d.mapping.size() == m_mappings.size());
	TORRENT_ASSERT(!d.disabled);

	if (d.upnp_connection) return;

	// this should not happen, but in case it does, don't fail at runtime
	if (i >= d.mapping.end_index()) return;

	std::shared_ptr<upnp> me(self());

	mapping_t& m = d.mapping[i];

	if (m.act == portmap_action::none
		|| m.protocol == portmap_protocol::none)
	{
#ifndef TORRENT_DISABLE_LOGGING
		log("mapping %u does not need updating, skipping", static_cast<int>(i));
#endif
		m.act = portmap_action::none;
		next(d, i);
		return;
	}

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

#ifndef TORRENT_DISABLE_LOGGING
	log("connecting to %s", d.hostname.c_str());
#endif
	if (m.act == portmap_action::add)
	{
		if (m.failcount > 5)
		{
			m.act = portmap_action::none;
			// giving up
			next(d, i);
			return;
		}

		if (d.upnp_connection) d.upnp_connection->close();
		d.upnp_connection = std::make_shared<http_connection>(m_io_service
			, m_resolver
			, std::bind(&upnp::on_upnp_map_response, self(), _1, _2
				, std::ref(d), i, _4), true, default_max_bottled_buffer_size
			, std::bind(&upnp::create_port_mapping, self(), _1, std::ref(d), i)
			, http_filter_handler()
#ifdef TORRENT_USE_OPENSSL
			, &m_ssl_ctx
#endif
			);

		d.upnp_connection->start(d.hostname, d.port
			, seconds(10), 1, nullptr, false, 5, m.local_ep.address());
	}
	else if (m.act == portmap_action::del)
	{
		if (d.upnp_connection) d.upnp_connection->close();
		d.upnp_connection = std::make_shared<http_connection>(m_io_service
			, m_resolver
			, std::bind(&upnp::on_upnp_unmap_response, self(), _1, _2
				, std::ref(d), i, _4), true, default_max_bottled_buffer_size
			, std::bind(&upnp::delete_port_mapping, self(), std::ref(d), i)
			, http_filter_handler()
#ifdef TORRENT_USE_OPENSSL
			, &m_ssl_ctx
#endif
			);
		d.upnp_connection->start(d.hostname, d.port
			, seconds(10), 1, nullptr, false, 5, m.local_ep.address());
	}

	m.act = portmap_action::none;
	m.expires = aux::time_now() + seconds(30);
}

void upnp::delete_port_mapping(rootdevice& d, port_mapping_t const i)
{
	TORRENT_ASSERT(is_single_thread());

	TORRENT_ASSERT(d.magic == 1337);

	if (!d.upnp_connection)
	{
		TORRENT_ASSERT(d.disabled);
#ifndef TORRENT_DISABLE_LOGGING
		log("unmapping %u aborted", static_cast<int>(i));
#endif
		return;
	}

	char const* soap_action = "DeletePortMapping";

	char soap[1024];
	std::snprintf(soap, sizeof(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:%s xmlns:u=\"%s\">"
		"<NewRemoteHost></NewRemoteHost>"
		"<NewExternalPort>%u</NewExternalPort>"
		"<NewProtocol>%s</NewProtocol>"
		"</u:%s></s:Body></s:Envelope>"
		, soap_action, d.service_namespace.c_str()
		, d.mapping[i].external_port
		, to_string(d.mapping[i].protocol)
		, soap_action);

	post(d, soap, soap_action);
}

void find_control_url(int const type, string_view str, parse_state& state)
{
	if (type == xml_start_tag)
	{
		state.tag_stack.push_back(str);
	}
	else if (type == xml_end_tag)
	{
		if (!state.tag_stack.empty())
		{
			if (state.in_service && string_equal_no_case(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;
		if (!state.in_service && state.top_tags("service", "servicetype"))
		{
			if (string_equal_no_case(str, "urn:schemas-upnp-org:service:WANIPConnection:1")
				|| string_equal_no_case(str, "urn:schemas-upnp-org:service:WANIPConnection:2")
				|| string_equal_no_case(str, "urn:schemas-upnp-org:service:WANPPPConnection:1"))
			{
				state.service_type.assign(str.begin(), str.end());
				state.in_service = true;
			}
		}
		else if (state.control_url.empty() && state.in_service
			&& state.top_tags("service", "controlurl") && str.size() > 0)
		{
			// default to the first (or only) control url in the router's listing
			state.control_url.assign(str.begin(), str.end());
		}
		else if (state.model.empty() && state.top_tags("device", "modelname"))
		{
			state.model.assign(str.begin(), str.end());
		}
		else if (string_equal_no_case(state.tag_stack.back(), "urlbase"))
		{
			state.url_base.assign(str.begin(), str.end());
		}
	}
}

void upnp::on_upnp_xml(error_code const& e
	, libtorrent::http_parser const& p, rootdevice& d
	, http_connection& c)
{
	TORRENT_ASSERT(is_single_thread());
	std::shared_ptr<upnp> me(self());

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

	if (m_closing) return;

	if (e && e != boost::asio::error::eof)
	{
#ifndef TORRENT_DISABLE_LOGGING
		if (should_log())
		{
			log("error while fetching control url from: %s: %s"
				, d.url.c_str(), convert_from_native(e.message()).c_str());
		}
#endif
		d.disabled = true;
		return;
	}

	if (!p.header_finished())
	{
#ifndef TORRENT_DISABLE_LOGGING
		log("error while fetching control url from: %s: incomplete HTTP message"
			, d.url.c_str());
#endif
		d.disabled = true;
		return;
	}

	if (p.status_code() != 200)
	{
#ifndef TORRENT_DISABLE_LOGGING
		if (should_log())
		{
			log("error while fetching control url from: %s: %s"
				, d.url.c_str(), convert_from_native(p.message()).c_str());
		}
#endif
		d.disabled = true;
		return;
	}

	parse_state s;
	auto body = p.get_body();
	xml_parse({body.data(), std::size_t(body.size())}, std::bind(&find_control_url, _1, _2, std::ref(s)));
	if (s.control_url.empty())
	{
#ifndef TORRENT_DISABLE_LOGGING
		log("could not find a port mapping interface in response from: %s"
			, d.url.c_str());
#endif
		d.disabled = true;
		return;
	}
	d.service_namespace = s.service_type;

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

	if (!s.model.empty()) m_model = s.model;

	if (!s.url_base.empty() && s.control_url.substr(0, 7) != "http://")
	{
		// 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;
	error_code ec;
	if (!d.control_url.empty() && d.control_url[0] == '/')
	{
		std::tie(protocol, auth, d.hostname, d.port, d.path)
			= parse_url_components(d.url, ec);
		if (d.port == -1) d.port = protocol == "http" ? 80 : 443;
		d.control_url = protocol + "://" + d.hostname + ":"
			+ to_string(d.port).data() + s.control_url;
	}

#ifndef TORRENT_DISABLE_LOGGING
	if (should_log())
	{
		log("found control URL: %s namespace %s "
			"urlbase: %s in response from %s"
			, d.control_url.c_str(), d.service_namespace.c_str()
			, s.url_base.c_str(), d.url.c_str());
	}
#endif

	std::tie(protocol, auth, d.hostname, d.port, d.path)
		= parse_url_components(d.control_url, ec);
	if (d.port == -1) d.port = protocol == "http" ? 80 : 443;

	if (ec)
	{
#ifndef TORRENT_DISABLE_LOGGING
		if (should_log())
		{
			log("failed to parse URL '%s': %s"
				, d.control_url.c_str(), convert_from_native(ec.message()).c_str());
		}
#endif
		d.disabled = true;
		return;
	}

	if (d.upnp_connection) d.upnp_connection->close();
	d.upnp_connection = std::make_shared<http_connection>(m_io_service
		, m_resolver
		, std::bind(&upnp::on_upnp_get_ip_address_response, self(), _1, _2
			, std::ref(d), _4), true, default_max_bottled_buffer_size
		, std::bind(&upnp::get_ip_address, self(), std::ref(d))
		, http_filter_handler()
#ifdef TORRENT_USE_OPENSSL
		, &m_ssl_ctx
#endif
		);
	d.upnp_connection->start(d.hostname, d.port
		, seconds(10), 1);
}

void upnp::get_ip_address(rootdevice& d)
{
	TORRENT_ASSERT(is_single_thread());

	TORRENT_ASSERT(d.magic == 1337);

	if (!d.upnp_connection)
	{
		TORRENT_ASSERT(d.disabled);
#ifndef TORRENT_DISABLE_LOGGING
		log("getting external IP address");
#endif
		return;
	}

	char const* soap_action = "GetExternalIPAddress";

	char soap[1024];
	std::snprintf(soap, sizeof(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:%s xmlns:u=\"%s\">"
		"</u:%s></s:Body></s:Envelope>"
		, soap_action, d.service_namespace.c_str()
		, soap_action);

	post(d, soap, soap_action);
}

void upnp::disable(error_code const& ec)
{
	TORRENT_ASSERT(is_single_thread());
	m_disabled = true;

	// kill all mappings
	for (auto i = m_mappings.begin(), end(m_mappings.end()); i != end; ++i)
	{
		if (i->protocol == portmap_protocol::none) continue;
		portmap_protocol const proto = i->protocol;
		i->protocol = portmap_protocol::none;
		m_callback.on_port_mapping(port_mapping_t(static_cast<int>(i - m_mappings.begin())), address(), 0, proto, ec
			, portmap_transport::upnp);
	}

	// we cannot clear the devices since there
	// might be outstanding requests relying on
	// the device entry being present when they
	// complete
	error_code e;
	m_broadcast_timer.cancel(e);
	m_refresh_timer.cancel(e);
	m_map_timer.cancel(e);
	m_unicast_socket.close(e);
	m_multicast_socket.close(e);
}

void find_error_code(int const type, string_view string, error_code_parse_state& state)
{
	if (state.exit) return;
	if (type == xml_start_tag && string == "errorCode")
	{
		state.in_error_code = true;
	}
	else if (type == xml_string && state.in_error_code)
	{
		state.error_code = std::atoi(string.to_string().c_str());
		state.exit = true;
	}
}

void find_ip_address(int const type, string_view string, ip_address_parse_state& state)
{
	find_error_code(type, string, state);
	if (state.exit) return;

	if (type == xml_start_tag && string == "NewExternalIPAddress")
	{
		state.in_ip_address = true;
	}
	else if (type == xml_string && state.in_ip_address)
	{
		state.ip_address.assign(string.begin(), string.end());
		state.exit = true;
	}
}

namespace {

	struct error_code_t
	{
		int code;
		char const* msg;
	};

	error_code_t error_codes[] =
	{
		{0, "no error"}
		, {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 "}
	};

}

struct upnp_error_category final : boost::system::error_category
{
	const char* name() const BOOST_SYSTEM_NOEXCEPT override
	{
		return "upnp";
	}

	std::string message(int ev) const override
	{
		int num_errors = sizeof(error_codes) / sizeof(error_codes[0]);
		error_code_t* end = error_codes + num_errors;
		error_code_t tmp = {ev, nullptr};
		error_code_t* e = std::lower_bound(error_codes, end, tmp
			, [] (error_code_t const& lhs, error_code_t const& rhs)
			{ return lhs.code < rhs.code; });
		if (e != end && e->code == ev)
		{
			return e->msg;
		}
		char msg[500];
		std::snprintf(msg, sizeof(msg), "unknown UPnP error (%d)", ev);
		return msg;
	}

	boost::system::error_condition default_error_condition(
		int ev) const BOOST_SYSTEM_NOEXCEPT override
	{
		return {ev, *this};
	}
};

boost::system::error_category& upnp_category()
{
	static upnp_error_category cat;
	return cat;
}

void upnp::on_upnp_get_ip_address_response(error_code const& e
	, libtorrent::http_parser const& p, rootdevice& d
	, http_connection& c)
{
	TORRENT_ASSERT(is_single_thread());
	std::shared_ptr<upnp> me(self());

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

	if (m_closing) return;

	if (e && e != boost::asio::error::eof)
	{
#ifndef TORRENT_DISABLE_LOGGING
		if (should_log())
		{
			log("error while getting external IP address: %s"
				, convert_from_native(e.message()).c_str());
		}
#endif
		if (num_mappings() > 0) update_map(d, port_mapping_t{0});
		return;
	}

	if (!p.header_finished())
	{
#ifndef TORRENT_DISABLE_LOGGING
		log("error while getting external IP address: incomplete http message");
#endif
		if (num_mappings() > 0) update_map(d, port_mapping_t{0});
		return;
	}

	if (p.status_code() != 200)
	{
#ifndef TORRENT_DISABLE_LOGGING
		if (should_log())
		{
			log("error while getting external IP address: %s"
				, convert_from_native(p.message()).c_str());
		}
#endif
		if (num_mappings() > 0) update_map(d, port_mapping_t{0});
		return;
	}

	// response may look like
	// <?xml version="1.0"?>
	// <s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/" s:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/">
	// <s:Body><u:GetExternalIPAddressResponse xmlns:u="urn:schemas-upnp-org:service:WANIPConnection:1">
	// <NewExternalIPAddress>192.168.160.19</NewExternalIPAddress>
	// </u:GetExternalIPAddressResponse>
	// </s:Body>
	// </s:Envelope>

	span<char const> body = p.get_body();
#ifndef TORRENT_DISABLE_LOGGING
	if (should_log())
	{
		log("get external IP address response: %s"
			, std::string(body.data(), static_cast<std::size_t>(body.size())).c_str());
	}
#endif

	ip_address_parse_state s;
	xml_parse({body.data(), std::size_t(body.size())}, std::bind(&find_ip_address, _1, _2, std::ref(s)));
#ifndef TORRENT_DISABLE_LOGGING
	if (s.error_code != -1)
	{
		log("error while getting external IP address, code: %d", s.error_code);
	}
#endif

	if (!s.ip_address.empty())
	{
#ifndef TORRENT_DISABLE_LOGGING
		log("got router external IP address %s", s.ip_address.c_str());
#endif
		d.external_ip = make_address(s.ip_address.c_str(), ignore_error);
	}
	else
	{
#ifndef TORRENT_DISABLE_LOGGING
		log("failed to find external IP address in response");
#endif
	}

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

void upnp::on_upnp_map_response(error_code const& e
	, libtorrent::http_parser const& p, rootdevice& d, port_mapping_t const mapping
	, http_connection& c)
{
	TORRENT_ASSERT(is_single_thread());
	std::shared_ptr<upnp> me(self());

	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 != boost::asio::error::eof)
	{
#ifndef TORRENT_DISABLE_LOGGING
		if (should_log())
		{
			log("error while adding port map: %s"
				, convert_from_native(e.message()).c_str());
		}
#endif
		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())
	{
#ifndef TORRENT_DISABLE_LOGGING
		log("error while adding port map: incomplete http message");
#endif
		next(d, mapping);
		return;
	}

	std::string const& ct = p.header("content-type");
	if (!ct.empty()
		&& ct.find_first_of("text/xml") == std::string::npos
		&& ct.find_first_of("text/soap+xml") == std::string::npos
		&& ct.find_first_of("application/xml") == std::string::npos
		&& ct.find_first_of("application/soap+xml") == std::string::npos
		)
	{
#ifndef TORRENT_DISABLE_LOGGING
		log("error while adding port map: invalid content-type, \"%s\". "
			"Expected text/xml or application/soap+xml", ct.c_str());
#endif
		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;
	span<char const> body = p.get_body();
	xml_parse({body.data(), std::size_t(body.size())}, std::bind(&find_error_code, _1, _2, std::ref(s)));

	if (s.error_code != -1)
	{
#ifndef TORRENT_DISABLE_LOGGING
		log("error while adding port map, code: %d", s.error_code);
#endif
	}

	mapping_t& m = d.mapping[mapping];

	if (s.error_code == 725)
	{
		// The gateway only supports permanent leases
		d.lease_duration = 0;
		m.act = portmap_action::add;
		++m.failcount;
		update_map(d, mapping);
		return;
	}
	else if (s.error_code == 727)
	{
		return_error(mapping, s.error_code);
	}
	else if ((s.error_code == 718 || s.error_code == 501) && m.failcount < 4)
	{
		// some routers return 501 action failed, instead of 716
		// The external port conflicts with another mapping
		// pick a random port
		m.external_port = 40000 + int(random(10000));
		m.act = portmap_action::add;
		++m.failcount;
		update_map(d, mapping);
		return;
	}
	else if (s.error_code != -1)
	{
		return_error(mapping, s.error_code);
	}

#ifndef TORRENT_DISABLE_LOGGING
	if (should_log())
	{
		log("map response: %s"
			, std::string(body.data(), static_cast<std::size_t>(body.size())).c_str());
	}
#endif

	if (s.error_code == -1)
	{
		m_callback.on_port_mapping(mapping, d.external_ip, m.external_port, m.protocol, error_code()
			, portmap_transport::upnp);
		if (d.lease_duration > 0)
		{
			time_point const now = aux::time_now();
			m.expires = now
				+ seconds(d.lease_duration * 3 / 4);
			time_point next_expire = m_refresh_timer.expires_at();
			if (next_expire < now || next_expire > m.expires)
			{
				ADD_OUTSTANDING_ASYNC("upnp::on_expire");
				error_code ec;
				m_refresh_timer.expires_at(m.expires, ec);
				m_refresh_timer.async_wait(std::bind(&upnp::on_expire, self(), _1));
			}
		}
		else
		{
			m.expires = max_time();
		}
		m.failcount = 0;
	}

	next(d, mapping);
}

void upnp::return_error(port_mapping_t const mapping, int const code)
{
	TORRENT_ASSERT(is_single_thread());
	int num_errors = sizeof(error_codes) / sizeof(error_codes[0]);
	error_code_t* end = error_codes + num_errors;
	error_code_t tmp = {code, nullptr};
	error_code_t* e = std::lower_bound(error_codes, end, tmp
		, [] (error_code_t const& lhs, error_code_t const& rhs)
		{ return lhs.code < rhs.code; });

	std::string error_string = "UPnP mapping error ";
	error_string += to_string(code).data();
	if (e != end && e->code == code)
	{
		error_string += ": ";
		error_string += e->msg;
	}
	portmap_protocol const proto = m_mappings[mapping].protocol;
	m_callback.on_port_mapping(mapping, address(), 0, proto, error_code(code, upnp_category())
		, portmap_transport::upnp);
}

void upnp::on_upnp_unmap_response(error_code const& e
	, libtorrent::http_parser const& p, rootdevice& d
	, port_mapping_t const mapping
	, http_connection& c)
{
	TORRENT_ASSERT(is_single_thread());
	std::shared_ptr<upnp> me(self());

	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 != boost::asio::error::eof)
	{
#ifndef TORRENT_DISABLE_LOGGING
		if (should_log())
		{
			log("error while deleting portmap: %s"
				, convert_from_native(e.message()).c_str());
		}
#endif
	}
	else if (!p.header_finished())
	{
#ifndef TORRENT_DISABLE_LOGGING
		log("error while deleting portmap: incomplete http message");
#endif
	}
	else if (p.status_code() != 200)
	{
#ifndef TORRENT_DISABLE_LOGGING
		if (should_log())
		{
			log("error while deleting portmap: %s"
				, convert_from_native(p.message()).c_str());
		}
#endif
	}
	else
	{
#ifndef TORRENT_DISABLE_LOGGING
		if (should_log())
		{
			span<char const> body = p.get_body();
			log("unmap response: %s"
				, std::string(body.data(), static_cast<std::size_t>(body.size())).c_str());
		}
#endif
	}

	error_code_parse_state s;
	if (p.header_finished())
	{
		span<char const> body = p.get_body();
		xml_parse({body.data(), std::size_t(body.size())}, std::bind(&find_error_code, _1, _2, std::ref(s)));
	}

	portmap_protocol const proto = m_mappings[mapping].protocol;

	m_callback.on_port_mapping(mapping, address(), 0, proto, p.status_code() != 200
		? error_code(p.status_code(), http_category())
		: error_code(s.error_code, upnp_category())
		, portmap_transport::upnp);

	d.mapping[mapping].protocol = portmap_protocol::none;

	// free the slot in global mappings
	auto pred = [mapping](rootdevice const& rd)
		{ return rd.mapping.end_index() <= mapping || rd.mapping[mapping].protocol == portmap_protocol::none; };
	if (std::all_of(m_devices.begin(), m_devices.end(), pred))
	{
		m_mappings[mapping].protocol = portmap_protocol::none;
	}

	next(d, mapping);
}

void upnp::on_expire(error_code const& ec)
{
	TORRENT_ASSERT(is_single_thread());
	COMPLETE_ASYNC("upnp::on_expire");
	if (ec) return;

	if (m_closing) return;

	time_point const now = aux::time_now();
	time_point next_expire = max_time();

	for (auto& dev : m_devices)
	{
		rootdevice& d = const_cast<rootdevice&>(dev);
		TORRENT_ASSERT(d.magic == 1337);
		if (d.disabled) continue;
		for (port_mapping_t m{0}; m < m_mappings.end_index(); ++m)
		{
			if (d.mapping[m].expires == max_time())
				continue;

			if (d.mapping[m].expires <= now)
			{
				d.mapping[m].act = portmap_action::add;
				update_map(d, m);
			}
			if (d.mapping[m].expires < next_expire)
			{
				next_expire = d.mapping[m].expires;
			}
		}
	}
	if (next_expire != max_time())
	{
		ADD_OUTSTANDING_ASYNC("upnp::on_expire");
		error_code e;
		m_refresh_timer.expires_at(next_expire, e);
		m_refresh_timer.async_wait(std::bind(&upnp::on_expire, self(), _1));
	}
}

void upnp::close()
{
	TORRENT_ASSERT(is_single_thread());

	error_code ec;
	m_refresh_timer.cancel(ec);
	m_broadcast_timer.cancel(ec);
	m_map_timer.cancel(ec);
	m_closing = true;
	m_unicast_socket.close(ec);
	m_multicast_socket.close(ec);

	for (auto& dev : m_devices)
	{
		rootdevice& d = const_cast<rootdevice&>(dev);
		TORRENT_ASSERT(d.magic == 1337);
		if (d.disabled || d.control_url.empty()) continue;
		for (auto& m : d.mapping)
		{
			if (m.protocol == portmap_protocol::none) continue;
			if (m.act == portmap_action::add)
			{
				m.act = portmap_action::none;
				continue;
			}
			m.act = portmap_action::del;
			m_mappings[port_mapping_t{static_cast<int>(&m - d.mapping.data())}].protocol = portmap_protocol::none;
		}
		if (num_mappings() > 0) update_map(d, port_mapping_t{0});
	}
}

}