libtorrent/src/web_connection_base.cpp

/*

Copyright (c) 2010, 2013-2017, 2019-2021, Arvid Norberg
Copyright (c) 2016, 2019, Alden Torres
Copyright (c) 2016, Andrei Kurushin
Copyright (c) 2017, Steven Siloti
Copyright (c) 2020, Paul-Louis Ageneau
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 <limits>
#include <cstdlib>

#include "libtorrent/web_connection_base.hpp"
#include "libtorrent/aux_/invariant_check.hpp"
#include "libtorrent/parse_url.hpp"
#include "libtorrent/peer_info.hpp"

namespace libtorrent {

	web_connection_base::web_connection_base(
		peer_connection_args& pack
		, web_seed_t const& web)
		: peer_connection(pack)
		, m_first_request(true)
		, m_ssl(false)
		, m_external_auth(web.auth)
		, m_extra_headers(web.extra_headers)
		, m_parser(http_parser::dont_parse_chunks)
		, m_body_start(0)
	{
		TORRENT_ASSERT(&web.peer_info == pack.peerinfo);
		// when going through a proxy, we don't necessarily have an endpoint here,
		// since the proxy might be resolving the hostname, not us
		TORRENT_ASSERT(web.endpoints.empty() || web.endpoints.front() == pack.endp);

		INVARIANT_CHECK;

		TORRENT_ASSERT(is_outgoing());

		TORRENT_ASSERT(!m_torrent.lock()->is_upload_only());

		// we only want left-over bandwidth
		// TODO: introduce a web-seed default class which has a low download priority

		std::string protocol;
		error_code ec;
		std::tie(protocol, m_basic_auth, m_host, m_port, m_path)
			= parse_url_components(web.url, ec);
		TORRENT_ASSERT(!ec);

		if (m_port == -1 && protocol == "http")
			m_port = 80;

#if TORRENT_USE_SSL
		if (protocol == "https")
		{
			m_ssl = true;
			if (m_port == -1) m_port = 443;
		}
#endif

		if (!m_basic_auth.empty())
			m_basic_auth = base64encode(m_basic_auth);

		m_server_string = m_host;
		aux::verify_encoding(m_server_string);
	}

	int web_connection_base::timeout() const
	{
		// since this is a web seed, change the timeout
		// according to the settings.
		return m_settings.get_int(settings_pack::urlseed_timeout);
	}

	void web_connection_base::start()
	{
		// avoid calling torrent::set_seed because it calls torrent::check_invariant
		// which fails because the m_num_connecting count is not consistent until
		// after we call peer_connection::start
		m_upload_only = true;
		peer_connection::start();
		// disconnect_if_redundant must be called after start to keep
		// m_num_connecting consistent
		disconnect_if_redundant();
	}

	web_connection_base::~web_connection_base() = default;

	void web_connection_base::on_connected()
	{
		std::shared_ptr<torrent> t = associated_torrent().lock();
		TORRENT_ASSERT(t);

		// it is always possible to request pieces
		incoming_unchoke();

		m_recv_buffer.reset(t->block_size() + 1024);
	}

	void web_connection_base::add_headers(std::string& request
		, aux::session_settings const& sett, bool const using_proxy) const
	{
		request += "Host: ";
		request += m_host;
		if ((m_first_request || m_settings.get_bool(settings_pack::always_send_user_agent))
			&& !m_settings.get_bool(settings_pack::anonymous_mode))
		{
			request += "\r\nUser-Agent: ";
			request += m_settings.get_str(settings_pack::user_agent);
		}
		if (!m_external_auth.empty())
		{
			request += "\r\nAuthorization: ";
			request += m_external_auth;
		}
		else if (!m_basic_auth.empty())
		{
			request += "\r\nAuthorization: Basic ";
			request += m_basic_auth;
		}
		if (sett.get_int(settings_pack::proxy_type) == settings_pack::http_pw)
		{
			request += "\r\nProxy-Authorization: Basic ";
			request += base64encode(sett.get_str(settings_pack::proxy_username)
				+ ":" + sett.get_str(settings_pack::proxy_password));
		}
		for (auto const& h : m_extra_headers)
		{
			request += "\r\n";
			request += h.first;
			request += ": ";
			request += h.second;
		}
		if (using_proxy) {
			request += "\r\nProxy-Connection: keep-alive";
		}
		if (m_first_request || using_proxy) {
			request += "\r\nConnection: keep-alive";
		}
	}

	// --------------------------
	// RECEIVE DATA
	// --------------------------

	void web_connection_base::get_specific_peer_info(peer_info& p) const
	{
		if (is_interesting()) p.flags |= peer_info::interesting;
		if (is_choked()) p.flags |= peer_info::choked;
		if (!is_connecting() && m_server_string.empty())
			p.flags |= peer_info::handshake;
		if (is_connecting()) p.flags |= peer_info::connecting;

		p.client = m_server_string;
	}

	bool web_connection_base::in_handshake() const
	{
		return m_server_string.empty();
	}

	void web_connection_base::on_sent(error_code const& error
		, std::size_t bytes_transferred)
	{
		INVARIANT_CHECK;

		if (error) return;
		sent_bytes(0, int(bytes_transferred));
	}


#if TORRENT_USE_INVARIANT_CHECKS
	void web_connection_base::check_invariant() const
	{
/*
		TORRENT_ASSERT(m_num_pieces == std::count(
			m_have_piece.begin()
			, m_have_piece.end()
			, true));
*/	}
#endif

}