/* Copyright (c) 2007-2016, 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 #include #include "libtorrent/lsd.hpp" #include "libtorrent/io.hpp" #include "libtorrent/http_tracker_connection.hpp" #include "libtorrent/buffer.hpp" #include "libtorrent/random.hpp" #include "libtorrent/http_parser.hpp" #include "libtorrent/socket_io.hpp" // for print_address #include "libtorrent/debug.hpp" #include "libtorrent/hex.hpp" // to_hex, from_hex #include "libtorrent/aux_/disable_warnings_push.hpp" #include #include #include #include "libtorrent/aux_/disable_warnings_pop.hpp" #include #include #include using namespace std::placeholders; namespace libtorrent { namespace { int render_lsd_packet(char* dst, int len, int listen_port , char const* info_hash_hex, int m_cookie, char const* host) { TORRENT_ASSERT(len > 0); return std::snprintf(dst, len, "BT-SEARCH * HTTP/1.1\r\n" "Host: %s:6771\r\n" "Port: %d\r\n" "Infohash: %s\r\n" "cookie: %x\r\n" "\r\n\r\n", host, listen_port, info_hash_hex, m_cookie); } } // anonymous namespace static error_code dummy; lsd::lsd(io_service& ios, peer_callback_t const& cb #ifndef TORRENT_DISABLE_LOGGING , log_callback_t const& log #endif ) : m_callback(cb) , m_socket(udp::endpoint(address_v4::from_string("239.192.152.143", dummy), 6771)) #if TORRENT_USE_IPV6 , m_socket6(udp::endpoint(address_v6::from_string("ff15::efc0:988f", dummy), 6771)) #endif #ifndef TORRENT_DISABLE_LOGGING , m_log_cb(log) #endif , m_broadcast_timer(ios) , m_cookie(random() & 0x7fffffff) , m_disabled(false) #if TORRENT_USE_IPV6 , m_disabled6(false) #endif { } #ifndef TORRENT_DISABLE_LOGGING TORRENT_FORMAT(2,3) void lsd::debug_log(char const* fmt, ...) const { va_list v; va_start(v, fmt); char buf[1024]; vsnprintf(buf, sizeof(buf), fmt, v); va_end(v); m_log_cb(buf); } #endif void lsd::start(error_code& ec) { m_socket.open(std::bind(&lsd::on_announce, self(), _1, _2, _3) , m_broadcast_timer.get_io_service(), ec); if (ec) return; #if TORRENT_USE_IPV6 m_socket6.open(std::bind(&lsd::on_announce, self(), _1, _2, _3) , m_broadcast_timer.get_io_service(), ec); #endif } lsd::~lsd() = default; void lsd::announce(sha1_hash const& ih, int listen_port, bool broadcast) { announce_impl(ih, listen_port, broadcast, 0); } void lsd::announce_impl(sha1_hash const& ih, int listen_port, bool broadcast , int retry_count) { #if TORRENT_USE_IPV6 if (m_disabled && m_disabled6) return; #else if (m_disabled) return; #endif char ih_hex[41]; aux::to_hex(ih.data(), 20, ih_hex); char msg[200]; #ifndef TORRENT_DISABLE_LOGGING debug_log("==> LSD: ih: %s port: %u\n", ih_hex, listen_port); #endif error_code ec; if (!m_disabled) { int msg_len = render_lsd_packet(msg, sizeof(msg), listen_port, ih_hex , m_cookie, "239.192.152.143"); m_socket.send(msg, msg_len, ec, broadcast ? broadcast_socket::flag_broadcast : 0); if (ec) { m_disabled = true; #ifndef TORRENT_DISABLE_LOGGING debug_log("*** LSD: failed to send message: (%d) %s", ec.value() , ec.message().c_str()); #endif } } #if TORRENT_USE_IPV6 if (!m_disabled6) { int msg_len = render_lsd_packet(msg, sizeof(msg), listen_port, ih_hex , m_cookie, "[ff15::efc0:988f]"); m_socket6.send(msg, msg_len, ec, broadcast ? broadcast_socket::flag_broadcast : 0); if (ec) { m_disabled6 = true; #ifndef TORRENT_DISABLE_LOGGING debug_log("*** LSD: failed to send message6: (%d) %s", ec.value() , ec.message().c_str()); #endif } } #endif ++retry_count; if (retry_count >= 3) return; #if TORRENT_USE_IPV6 if (m_disabled && m_disabled6) return; #else if (m_disabled) return; #endif ADD_OUTSTANDING_ASYNC("lsd::resend_announce"); m_broadcast_timer.expires_from_now(seconds(2 * retry_count), ec); m_broadcast_timer.async_wait(std::bind(&lsd::resend_announce, self(), _1 , ih, listen_port, retry_count)); } void lsd::resend_announce(error_code const& e, sha1_hash const& info_hash , int listen_port, int retry_count) { COMPLETE_ASYNC("lsd::resend_announce"); if (e) return; announce_impl(info_hash, listen_port, false, retry_count); } void lsd::on_announce(udp::endpoint const& from, char* buf , std::size_t bytes_transferred) { using namespace libtorrent::detail; http_parser p; bool error = false; p.incoming(span(buf, bytes_transferred), error); if (!p.header_finished() || error) { #ifndef TORRENT_DISABLE_LOGGING debug_log("<== LSD: incomplete HTTP message"); #endif return; } if (p.method() != "bt-search") { #ifndef TORRENT_DISABLE_LOGGING debug_log("<== LSD: invalid HTTP method: %s", p.method().c_str()); #endif return; } std::string const& port_str = p.header("port"); if (port_str.empty()) { #ifndef TORRENT_DISABLE_LOGGING debug_log("<== LSD: invalid BT-SEARCH, missing port"); #endif return; } int port = std::atoi(port_str.c_str()); typedef std::multimap headers_t; headers_t const& headers = p.headers(); headers_t::const_iterator cookie_iter = headers.find("cookie"); if (cookie_iter != headers.end()) { // we expect it to be hexadecimal // if it isn't, it's not our cookie anyway std::int32_t cookie = strtol(cookie_iter->second.c_str(), nullptr, 16); if (cookie == m_cookie) { #ifndef TORRENT_DISABLE_LOGGING debug_log("<== LSD: ignoring packet (cookie matched our own): %x == %x" , cookie, m_cookie); #endif return; } } std::pair ihs = headers.equal_range("infohash"); for (headers_t::const_iterator i = ihs.first; i != ihs.second; ++i) { std::string const& ih_str = i->second; if (ih_str.size() != 40) { #ifndef TORRENT_DISABLE_LOGGING debug_log("<== LSD: invalid BT-SEARCH, invalid infohash: %s" , ih_str.c_str()); #endif continue; } sha1_hash ih(nullptr); aux::from_hex(ih_str.c_str(), 40, ih.data()); if (!ih.is_all_zeros() && port != 0) { #ifndef TORRENT_DISABLE_LOGGING debug_log("<== LSD: %s:%d ih: %s" , print_address(from.address()).c_str() , port, ih_str.c_str()); #endif // we got an announce, pass it on through the callback TORRENT_TRY { m_callback(tcp::endpoint(from.address(), port), ih); } TORRENT_CATCH(std::exception&) {} } } } void lsd::close() { m_socket.close(); #if TORRENT_USE_IPV6 m_socket6.close(); #endif error_code ec; m_broadcast_timer.cancel(ec); m_disabled = true; #if TORRENT_USE_IPV6 m_disabled6 = true; #endif m_callback.clear(); } } // libtorrent namespace