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|
-- |
-- Copyright : (c) Sam Truzjan 2013
-- License : BSD3
-- Maintainer : pxqr.sta@gmail.com
-- Stability : experimental
-- Portability : portable
--
-- BitTorrent uses a \"distributed sloppy hash table\" (DHT) for
-- storing peer contact information for \"trackerless\" torrents. In
-- effect, each peer becomes a tracker.
--
-- Normally you don't need to import other DHT modules.
--
-- For more info see:
-- <http://www.bittorrent.org/beps/bep_0005.html>
--
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE TemplateHaskell #-}
module Network.BitTorrent.DHT
( -- * Distributed Hash Table
DHT
, dht
, Network.BitTorrent.DHT.bootstrap
, Network.BitTorrent.DHT.lookup
, Network.BitTorrent.DHT.insert
, Network.BitTorrent.DHT.delete
) where
import Control.Applicative
import Control.Concurrent.Lifted
import Control.Exception.Lifted
import Control.Monad
import Control.Monad.Logger
import Data.List as L
import Data.Monoid
import Data.Text as T
import Network.Socket (PortNumber)
import Text.PrettyPrint as PP hiding ((<>))
import Text.PrettyPrint.Class
import Data.Torrent.InfoHash
import Network.BitTorrent.Core
import Network.BitTorrent.DHT.Message
import Network.BitTorrent.DHT.Session
{-----------------------------------------------------------------------
-- Handlers
-----------------------------------------------------------------------}
pingH :: Address ip => NodeHandler ip
pingH = nodeHandler $ \ _ Ping -> do
$(logDebug) "ping received, sending pong"
return Ping
findNodeH :: Address ip => NodeHandler ip
findNodeH = nodeHandler $ \ _ (FindNode nid) -> do
$(logDebug) "find_node received, sending closest nodes back"
NodeFound <$> getClosest nid
getPeersH :: Address ip => NodeHandler ip
getPeersH = nodeHandler $ \ naddr (GetPeers ih) -> do
$(logDebug) "get_peers received, trying to find peers"
GotPeers <$> getPeerList ih <*> grantToken naddr
announceH :: Address ip => NodeHandler ip
announceH = nodeHandler $ \ naddr (Announce {..}) -> do
$(logDebug) "announce received, trying to check token"
checkToken naddr sessionToken
case fromAddr naddr of
Nothing -> undefined
Just paddr -> do
insertPeer topic paddr
return Announced
handlers :: Address ip => [NodeHandler ip]
handlers = [pingH, findNodeH, getPeersH, announceH]
{-----------------------------------------------------------------------
-- Query
-----------------------------------------------------------------------}
-- | Run DHT on specified port. <add note about resources>
dht :: Address ip
=> Options -- ^ normally you need to use 'Data.Default.def';
-> NodeAddr ip -- ^ address to bind this node;
-> DHT ip a -- ^ actions to run: 'bootstrap', 'lookup', etc;
-> IO a -- ^ result.
dht = runDHT handlers
{-# INLINE dht #-}
-- | One good node may be sufficient. The list of bootstrapping nodes
-- usually obtained from 'Data.Torrent.tNodes' field.
--
-- (TODO) This operation is asynchronous and do not block.
--
bootstrap :: Address ip => [NodeAddr ip] -> DHT ip ()
bootstrap startNodes = do
$(logInfoS) "bootstrap" "Start node bootstrapping"
mapM_ insertClosest startNodes
$(logInfoS) "bootstrap" "Node bootstrapping finished"
where
insertClosest addr = do
nid <- getNodeId
result <- try $ FindNode nid <@> addr
case result of
Left e -> do
$(logWarnS) "bootstrap" $ T.pack $ show (e :: IOError)
Right (NodeFound closest) -> do
$(logDebug) ("Get a list of closest nodes: " <>
T.pack (PP.render (pretty closest)))
forM_ (L.take 2 closest) $ \ info @ NodeInfo {..} -> do
_ <- insertNode info
let prettyAddr = T.pack (show (pretty nodeAddr))
$(logInfoS) "bootstrap" $ "table detalization" <> prettyAddr
fork $ insertClosest nodeAddr
-- | Get list of peers which downloading this torrent.
--
-- (TODO) This operation is synchronous and do block.
--
lookup :: Address ip => InfoHash -> DHT ip [PeerAddr ip]
lookup topic = getClosestHash topic >>= collect
-- TODO retry getClosestHash if bucket is empty
where
collect nodes = L.concat <$> forM (nodeAddr <$> nodes) retrieve
retrieve addr = do
GotPeers {..} <- GetPeers topic <@> addr
either collect pure peers
-- | Announce that /this/ peer may have some pieces of the specified
-- torrent.
--
-- (TODO) This operation is asynchronous and do not block.
--
insert :: Address ip => InfoHash -> PortNumber -> DHT ip ()
insert ih port = do
nodes <- getClosestHash ih
forM_ (nodeAddr <$> nodes) $ \ addr -> do
-- GotPeers {..} <- GetPeers ih <@> addr
-- Announced <- Announce False ih undefined grantedToken <@> addr
return ()
-- | Stop announcing /this/ peer for the specified torrent.
--
-- This operation is atomic and do not block.
--
delete :: Address ip => InfoHash -> DHT ip ()
delete = error "DHT.delete: not implemented"
|
