/* 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 #include #include #include // for vsnprintf #include "libtorrent/lsd.hpp" #include "libtorrent/time.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_/numeric_cast.hpp" using namespace std::placeholders; namespace libtorrent { namespace { int render_lsd_packet(char* dst, int const len, int const listen_port , char const* info_hash_hex, int const cookie, char const* host) { TORRENT_ASSERT(len > 0); return std::snprintf(dst, aux::numeric_cast(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, cookie); } } // anonymous namespace static error_code dummy; lsd::lsd(io_service& ios, aux::lsd_callback& cb) : m_callback(cb) , m_socket(udp::endpoint(make_address_v4("239.192.152.143", dummy), 6771)) #if TORRENT_USE_IPV6 , m_socket6(udp::endpoint(make_address_v6("ff15::efc0:988f", dummy), 6771)) #endif , m_broadcast_timer(ios) , m_cookie((random(0x7fffffff) ^ std::uintptr_t(this)) & 0x7fffffff) , m_disabled(false) #if TORRENT_USE_IPV6 , m_disabled6(false) #endif { } #ifndef TORRENT_DISABLE_LOGGING bool lsd::should_log() const { return m_callback.should_log_lsd(); } TORRENT_FORMAT(2, 3) void lsd::debug_log(char const* fmt, ...) const { if (!should_log()) return; va_list v; va_start(v, fmt); char buf[1024]; std::vsnprintf(buf, sizeof(buf), fmt, v); va_end(v); m_callback.log_lsd(buf); } #endif void lsd::start(error_code& ec) { m_socket.open(std::bind(&lsd::on_announce, self(), _1, _2) , 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) , 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 const listen_port , bool const broadcast, int retry_count) { #if TORRENT_USE_IPV6 if (m_disabled && m_disabled6) return; #else if (m_disabled) return; #endif char msg[200]; #ifndef TORRENT_DISABLE_LOGGING debug_log("==> LSD: ih: %s port: %u\n", aux::to_hex(ih).c_str(), listen_port); #endif error_code ec; if (!m_disabled) { int const msg_len = render_lsd_packet(msg, sizeof(msg), listen_port, aux::to_hex(ih).c_str() , 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 if (should_log()) { debug_log("*** LSD: failed to send message: (%d) %s", ec.value() , ec.message().c_str()); } #endif } } #if TORRENT_USE_IPV6 if (!m_disabled6) { int const msg_len = render_lsd_packet(msg, sizeof(msg), listen_port, aux::to_hex(ih).c_str() , 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 if (should_log()) { 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, span buf) { http_parser p; bool error = false; p.incoming(buf, 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; } long const port = std::strtol(port_str.c_str(), nullptr, 10); if (port <= 0 || port >= int(std::numeric_limits::max())) { #ifndef TORRENT_DISABLE_LOGGING debug_log("<== LSD: invalid BT-SEARCH port value: %s", port_str.c_str()); #endif return; } auto const& headers = p.headers(); auto const 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 long const cookie = std::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" , m_cookie); #endif return; } } auto const ihs = headers.equal_range("infohash"); for (auto 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; aux::from_hex(ih_str, ih.data()); if (!ih.is_all_zeros() && port != 0) { #ifndef TORRENT_DISABLE_LOGGING if (should_log()) { debug_log("<== LSD: %s:%d ih: %s" , print_address(from.address()).c_str() , int(port), ih_str.c_str()); } #endif // we got an announce, pass it on through the callback m_callback.on_lsd_peer(tcp::endpoint(from.address(), std::uint16_t(port)), ih); } } } 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 } } // libtorrent namespace