171 lines
5.4 KiB
C++
171 lines
5.4 KiB
C++
/*
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Copyright (c) 2006-2018, Arvid Norberg & Daniel Wallin
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All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions
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are met:
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* Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in
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the documentation and/or other materials provided with the distribution.
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* Neither the name of the author nor the names of its
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contributors may be used to endorse or promote products derived
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from this software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef TRAVERSAL_ALGORITHM_050324_HPP
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#define TRAVERSAL_ALGORITHM_050324_HPP
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#include <vector>
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#include <set>
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#include <memory>
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#include <libtorrent/kademlia/node_id.hpp>
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#include <libtorrent/kademlia/routing_table.hpp>
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#include <libtorrent/kademlia/observer.hpp>
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#include <libtorrent/address.hpp>
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#include <libtorrent/flags.hpp>
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#include <libtorrent/bdecode.hpp>
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namespace libtorrent {
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struct dht_lookup;
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namespace dht {
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class node;
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struct node_endpoint;
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using traversal_flags_t = libtorrent::flags::bitfield_flag<std::uint8_t, struct traversal_flags_tag>;
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// this class may not be instantiated as a stack object
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struct TORRENT_EXTRA_EXPORT traversal_algorithm
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: std::enable_shared_from_this<traversal_algorithm>
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{
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void traverse(node_id const& id, udp::endpoint const& addr);
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void finished(observer_ptr o);
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static constexpr traversal_flags_t prevent_request = 0_bit;
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static constexpr traversal_flags_t short_timeout = 1_bit;
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void failed(observer_ptr o, traversal_flags_t flags = {});
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virtual ~traversal_algorithm();
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void status(dht_lookup& l);
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virtual char const* name() const;
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virtual void start();
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node_id const& target() const { return m_target; }
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void resort_result(observer*);
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void add_entry(node_id const& id, udp::endpoint const& addr, observer_flags_t flags);
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traversal_algorithm(node& dht_node, node_id const& target);
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traversal_algorithm(traversal_algorithm const&) = delete;
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traversal_algorithm& operator=(traversal_algorithm const&) = delete;
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int invoke_count() const { TORRENT_ASSERT(m_invoke_count >= 0); return m_invoke_count; }
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int branch_factor() const { TORRENT_ASSERT(m_branch_factor >= 0); return m_branch_factor; }
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node& get_node() const { return m_node; }
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#ifndef TORRENT_DISABLE_LOGGING
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std::uint32_t id() const { return m_id; }
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#endif
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protected:
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std::shared_ptr<traversal_algorithm> self()
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{ return shared_from_this(); }
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// returns true if we're done
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bool add_requests();
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void add_router_entries();
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void init();
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virtual void done();
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// should construct an algorithm dependent
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// observer in ptr.
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virtual observer_ptr new_observer(udp::endpoint const& ep
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, node_id const& id);
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virtual bool invoke(observer_ptr) { return false; }
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int num_responses() const { return m_responses; }
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int num_timeouts() const { return m_timeouts; }
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node& m_node;
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// this vector is sorted by node-id distance from our node id. Closer nodes
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// are earlier in the vector. However, not the entire vector is necessarily
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// sorted, the tail of the vector may contain nodes out-of-order. This is
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// used when bootstrapping. The ``m_sorted_results`` member indicates how
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// many of the first elements are sorted.
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std::vector<observer_ptr> m_results;
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int num_sorted_results() const { return m_sorted_results; }
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private:
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node_id const m_target;
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std::int8_t m_invoke_count = 0;
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std::int8_t m_branch_factor = 3;
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// the number of elements at the beginning of m_results that are sorted by
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// node_id.
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std::int8_t m_sorted_results = 0;
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std::int16_t m_responses = 0;
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std::int16_t m_timeouts = 0;
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#ifndef TORRENT_DISABLE_LOGGING
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// this is a unique ID for this specific traversal_algorithm instance,
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// just used for logging
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std::uint32_t m_id;
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#endif
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// the IP addresses of the nodes in m_results
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std::set<std::uint32_t> m_peer4_prefixes;
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#if TORRENT_USE_IPV6
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std::set<std::uint64_t> m_peer6_prefixes;
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#endif
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#ifndef TORRENT_DISABLE_LOGGING
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void log_timeout(observer_ptr const& o, char const* prefix) const;
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#endif
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};
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void look_for_nodes(char const* nodes_key, udp const& protocol
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, bdecode_node const& r, std::function<void(node_endpoint const&)> f);
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struct traversal_observer : observer
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{
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traversal_observer(
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std::shared_ptr<traversal_algorithm> algorithm
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, udp::endpoint const& ep, node_id const& id)
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: observer(std::move(algorithm), ep, id)
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{}
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// parses out "nodes" and keeps traversing
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void reply(msg const&) override;
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};
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} // namespace dht
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} // namespace libtorrent
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#endif // TRAVERSAL_ALGORITHM_050324_HPP
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