reset()

void reset ();

This member function set the counters to zero.

update_node_ids()

virtual void update_node_ids (std::vector<node_id> const& ids) = 0;

This member function notifies the list of all node's ids of each DHT running inside libtorrent. It's advisable that the concrete implementation keeps a copy of this list for an eventual prioritization when deleting an element to make room for a new one.

get_peers()

virtual bool get_peers (sha1_hash const& info_hash
      , bool noseed, bool scrape, address const& requester
      , entry& peers) const = 0;

This function retrieve the peers tracked by the DHT corresponding to the given info_hash. You can specify if you want only seeds and/or you are scraping the data.

For future implementers: If the torrent tracked contains a name, such a name must be stored as a string in peers["n"]

If the scrape parameter is true, you should fill these keys:

peers["BFpe"]

with the standard bit representation of a 256 bloom filter containing the downloaders

peers["BFsd"]

with the standard bit representation of a 256 bloom filter containing the seeders

If the scrape parameter is false, you should fill the key peers["values"] with a list containing a subset of peers tracked by the given info_hash. Such a list should consider the value of settings_pack::dht_max_peers_reply. If noseed is true only peers marked as no seed should be included.

returns true if the maximum number of peers are stored for this info_hash.

announce_peer()

virtual void announce_peer (sha1_hash const& info_hash
      , tcp::endpoint const& endp
      , string_view name, bool seed) = 0;

This function is named announce_peer for consistency with the upper layers, but has nothing to do with networking. Its only responsibility is store the peer in such a way that it's returned in the entry with the lookup_peers.

The name parameter is the name of the torrent if provided in the announce_peer DHT message. The length of this value should have a maximum length in the final storage. The default implementation truncate the value for a maximum of 50 characters.

get_immutable_item()

virtual bool get_immutable_item (sha1_hash const& target
      , entry& item) const = 0;

This function retrieves the immutable item given its target hash.

For future implementers: The value should be returned as an entry in the key item["v"].

returns true if the item is found and the data is returned inside the (entry) out parameter item.

put_immutable_item()

virtual void put_immutable_item (sha1_hash const& target
      , span<char const> buf
      , address const& addr) = 0;

Store the item's data. This layer is only for storage. The authentication of the item is performed by the upper layer.

For implementers: This data can be stored only if the target is not already present. The implementation should consider the value of settings_pack::dht_max_dht_items.

get_mutable_item_seq()

virtual bool get_mutable_item_seq (sha1_hash const& target
      , sequence_number& seq) const = 0;

This function retrieves the sequence number of a mutable item.

returns true if the item is found and the data is returned inside the out parameter seq.

get_mutable_item()

virtual bool get_mutable_item (sha1_hash const& target
      , sequence_number seq, bool force_fill
      , entry& item) const = 0;

This function retrieves the mutable stored in the DHT.

For implementers: The item sequence should be stored in the key item["seq"]. if force_fill is true or (0 <= seq and seq < item["seq"]) the following keys should be filled item["v"] - with the value no encoded. item["sig"] - with a string representation of the signature. item["k"] - with a string representation of the public key.

returns true if the item is found and the data is returned inside the (entry) out parameter item.

put_mutable_item()

virtual void put_mutable_item (sha1_hash const& target
      , span<char const> buf
      , signature const& sig
      , sequence_number seq
      , public_key const& pk
      , span<char const> salt
      , address const& addr) = 0;

Store the item's data. This layer is only for storage. The authentication of the item is performed by the upper layer.

For implementers: The sequence number should be checked if the item is already present. The implementation should consider the value of settings_pack::dht_max_dht_items.

get_infohashes_sample()

virtual int get_infohashes_sample (entry& item) = 0;

This function retrieves a sample info-hashes

For implementers: The info-hashes should be stored in ["samples"] (N x 20 bytes). the following keys should be filled item["interval"] - the subset refresh interval in seconds. item["num"] - number of info-hashes in storage.

Internally, this function is allowed to lazily evaluate, cache and modify the actual sample to put in item

returns the number of info-hashes in the sample.

tick()

virtual void tick () = 0;

This function is called periodically (non-constant frequency).

For implementers: Use this functions for expire peers or items or any other storage cleanup.

counters()

virtual dht_storage_counters counters () const = 0;

return stats counters for the store