/* Copyright (c) 2013, Steven Siloti 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 #include #include namespace libtorrent { namespace dht { void get_item::got_data(bdecode_node const& v, public_key const& pk, sequence_number const seq, signature const& sig) { // we received data! // if no data_callback, we needn't care about the data we get. // only put_immutable_item no data_callback if (!m_data_callback) return; // for get_immutable_item if (m_immutable) { // If m_data isn't empty, we should have post alert. if (!m_data.empty()) return; sha1_hash incoming_target = item_target_id(v.data_section()); if (incoming_target != target()) return; m_data.assign(v); // There can only be one true immutable item with a given id // Now that we've got it and the user doesn't want to do a put // there's no point in continuing to query other nodes m_data_callback(m_data, true); done(); return; } // immutable data should have been handled before this line, only mutable // data can reach here, which means pk, sig and seq must be valid. std::string const salt_copy(m_data.salt()); sha1_hash const incoming_target = item_target_id(salt_copy, pk); if (incoming_target != target()) return; // this is mutable data. If it passes the signature // check, remember it. Just keep the version with // the highest sequence number. if (m_data.empty() || m_data.seq() < seq) { if (!m_data.assign(v, salt_copy, seq, pk, sig)) return; // for get_item, we should call callback when we get data, // even if the date is not authoritative, we can update later. // so caller can get response ASAP without waiting transaction // time-out (15 seconds). // for put_item, the callback function will do nothing // if the data is non-authoritative. m_data_callback(m_data, false); } } get_item::get_item( node& dht_node , node_id const& target , data_callback const& dcallback , nodes_callback const& ncallback) : find_data(dht_node, target, ncallback) , m_data_callback(dcallback) , m_immutable(true) { } get_item::get_item( node& dht_node , public_key const& pk , span salt , data_callback const& dcallback , nodes_callback const& ncallback) : find_data(dht_node, item_target_id(salt, pk), ncallback) , m_data_callback(dcallback) , m_data(pk, salt) , m_immutable(false) { } char const* get_item::name() const { return "get"; } observer_ptr get_item::new_observer(udp::endpoint const& ep , node_id const& id) { auto o = m_node.m_rpc.allocate_observer(self(), ep, id); #if TORRENT_USE_ASSERTS if (o) o->m_in_constructor = false; #endif return o; } bool get_item::invoke(observer_ptr o) { if (m_done) return false; entry e; e["y"] = "q"; entry& a = e["a"]; e["q"] = "get"; a["target"] = target().to_string(); m_node.stats_counters().inc_stats_counter(counters::dht_get_out); return m_node.m_rpc.invoke(e, o->target_ep(), o); } void get_item::done() { // no data_callback for immutable item put if (!m_data_callback) return find_data::done(); if (m_data.is_mutable() || m_data.empty()) { // for mutable data, now we have authoritative data since // we've heard from everyone, to be sure we got the // latest version of the data (i.e. highest sequence number) m_data_callback(m_data, true); #if TORRENT_USE_ASSERTS if (m_data.is_mutable()) { TORRENT_ASSERT(target() == item_target_id(m_data.salt(), m_data.pk())); } #endif } find_data::done(); } void get_item_observer::reply(msg const& m) { public_key pk{}; signature sig{}; sequence_number seq{0}; bdecode_node const r = m.message.dict_find_dict("r"); if (!r) { #ifndef TORRENT_DISABLE_LOGGING get_observer()->log(dht_logger::traversal, "[%p] missing response dict" , static_cast(algorithm())); #endif timeout(); return; } bdecode_node const k = r.dict_find_string("k"); if (k && k.string_length() == public_key::len) std::memcpy(pk.bytes.data(), k.string_ptr(), public_key::len); bdecode_node const s = r.dict_find_string("sig"); if (s && s.string_length() == signature::len) std::memcpy(sig.bytes.data(), s.string_ptr(), signature::len); bdecode_node const q = r.dict_find_int("seq"); if (q) { seq = sequence_number(q.int_value()); } else if (k && s) { timeout(); return; } bdecode_node v = r.dict_find("v"); if (v) { static_cast(algorithm())->got_data(v, pk, seq, sig); } find_data_observer::reply(m); } } } // namespace libtorrent::dht