224 lines
6.8 KiB
C++
224 lines
6.8 KiB
C++
/*
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Copyright (c) 2006-2012, Arvid Norberg
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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 ROUTING_TABLE_HPP
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#define ROUTING_TABLE_HPP
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#include <vector>
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#include <boost/cstdint.hpp>
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#include <boost/utility.hpp>
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#include <boost/tuple/tuple.hpp>
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#include <boost/array.hpp>
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#include <set>
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#include <list>
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#include <libtorrent/kademlia/logging.hpp>
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#include <libtorrent/kademlia/node_id.hpp>
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#include <libtorrent/kademlia/node_entry.hpp>
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#include <libtorrent/session_settings.hpp>
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#include <libtorrent/size_type.hpp>
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#include <libtorrent/assert.hpp>
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#include <libtorrent/ptime.hpp>
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namespace libtorrent
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{
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struct session_status;
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}
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namespace libtorrent { namespace dht
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{
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#ifdef TORRENT_DHT_VERBOSE_LOGGING
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TORRENT_DECLARE_LOG(table);
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#endif
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typedef std::vector<node_entry> bucket_t;
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struct routing_table_node
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{
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bucket_t replacements;
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bucket_t live_nodes;
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ptime last_active;
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};
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// differences in the implementation from the description in
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// the paper:
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//
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// * Nodes are not marked as being stale, they keep a counter
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// that tells how many times in a row they have failed. When
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// a new node is to be inserted, the node that has failed
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// the most times is replaced. If none of the nodes in the
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// bucket has failed, then it is put in the replacement
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// cache (just like in the paper).
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class TORRENT_EXTRA_EXPORT routing_table
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{
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public:
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routing_table(node_id const& id, int bucket_size
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, dht_settings const& settings);
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void status(session_status& s) const;
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void node_failed(node_id const& id, udp::endpoint const& ep);
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// adds an endpoint that will never be added to
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// the routing table
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void add_router_node(udp::endpoint router);
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// iterates over the router nodes added
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typedef std::set<udp::endpoint>::const_iterator router_iterator;
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router_iterator router_begin() const { return m_router_nodes.begin(); }
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router_iterator router_end() const { return m_router_nodes.end(); }
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bool add_node(node_entry e);
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// this function is called every time the node sees
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// a sign of a node being alive. This node will either
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// be inserted in the k-buckets or be moved to the top
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// of its bucket.
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bool node_seen(node_id const& id, udp::endpoint ep, int rtt);
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// this may add a node to the routing table and mark it as
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// not pinged. If the bucket the node falls into is full,
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// the node will be ignored.
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void heard_about(node_id const& id, udp::endpoint const& ep);
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// if any bucket in the routing table needs to be refreshed
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// this function will return true and set the target to an
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// appropriate target inside that bucket
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bool need_refresh(node_id& target) const;
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enum
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{
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include_failed = 1
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};
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// fills the vector with the count nodes from our buckets that
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// are nearest to the given id.
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void find_node(node_id const& id, std::vector<node_entry>& l
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, int options, int count = 0);
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int bucket_size(int bucket) const
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{
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int num_buckets = m_buckets.size();
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if (num_buckets == 0) return 0;
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if (bucket < num_buckets) bucket = num_buckets - 1;
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table_t::const_iterator i = m_buckets.begin();
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std::advance(i, bucket);
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return (int)i->live_nodes.size();
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}
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void for_each_node(void (*)(void*, node_entry const&)
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, void (*)(void*, node_entry const&), void* userdata) const;
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int bucket_size() const { return m_bucket_size; }
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boost::tuple<int, int> size() const;
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size_type num_global_nodes() const;
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// returns true if there are no working nodes
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// in the routing table
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bool need_bootstrap() const;
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int num_active_buckets() const { return m_buckets.size(); }
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void replacement_cache(bucket_t& nodes) const;
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#if defined TORRENT_DHT_VERBOSE_LOGGING || defined TORRENT_DEBUG
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// used for debug and monitoring purposes. This will print out
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// the state of the routing table to the given stream
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void print_state(std::ostream& os) const;
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#endif
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void touch_bucket(node_id const& target);
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int bucket_limit(int bucket) const;
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private:
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typedef std::list<routing_table_node> table_t;
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table_t::iterator find_bucket(node_id const& id);
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void split_bucket();
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// return a pointer the node_entry with the given endpoint
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// or 0 if we don't have such a node. Both the address and the
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// port has to match
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node_entry* find_node(udp::endpoint const& ep, routing_table::table_t::iterator* bucket);
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// constant called k in paper
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int m_bucket_size;
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dht_settings const& m_settings;
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// (k-bucket, replacement cache) pairs
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// the first entry is the bucket the furthest
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// away from our own ID. Each time the bucket
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// closest to us (m_buckets.back()) has more than
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// bucket size nodes in it, another bucket is
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// added to the end and it's split up between them
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table_t m_buckets;
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node_id m_id; // our own node id
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// the last time need_bootstrap() returned true
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mutable ptime m_last_bootstrap;
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// the last time the routing table was refreshed.
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// this is used to stagger buckets needing refresh
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// to be at least 45 seconds apart.
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mutable ptime m_last_refresh;
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// the last time we refreshed our own bucket
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// refreshed every 15 minutes
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mutable ptime m_last_self_refresh;
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// this is a set of all the endpoints that have
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// been identified as router nodes. They will
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// be used in searches, but they will never
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// be added to the routing table.
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std::set<udp::endpoint> m_router_nodes;
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// these are all the IPs that are in the routing
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// table. It's used to only allow a single entry
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// per IP in the whole table. Currently only for
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// IPv4
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std::set<address_v4::bytes_type> m_ips;
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};
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} } // namespace libtorrent::dht
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#endif // ROUTING_TABLE_HPP
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