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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 #-}
{-# LANGUAGE TypeOperators #-}
module Network.BitTorrent.DHT
( -- * Distributed Hash Table
DHT
, Options (..)
, dht
-- * Bootstrapping
, tNodes
, defaultBootstrapNodes
, resolveHostName
, bootstrap
, isBootstrapped
-- * Initialization
, snapshot
, restore
-- * Operations
, Network.BitTorrent.DHT.lookup
, Network.BitTorrent.DHT.insert
, Network.BitTorrent.DHT.delete
-- * Embedding
-- ** Session
, LogFun
, Node
, handlers
, startNode
-- ** Monad
, MonadDHT (..)
, runDHT
) where
import Control.Applicative
import Control.Monad.Logger
import Control.Monad.Reader
import Control.Monad.Trans
import Control.Exception
import Data.ByteString as BS
import Data.Conduit as C
import Data.Conduit.List as C
import Network.Socket
import Data.Torrent (tNodes)
import Data.Torrent.InfoHash
import Network.BitTorrent.Core
import Network.BitTorrent.DHT.Query
import Network.BitTorrent.DHT.Session
import Network.BitTorrent.DHT.Routing as T
{-----------------------------------------------------------------------
-- DHT types
-----------------------------------------------------------------------}
class MonadDHT m where
liftDHT :: DHT IPv4 a -> m a
instance MonadDHT (DHT IPv4) where
liftDHT = id
-- | 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 opts addr action = do
runStderrLoggingT $ LoggingT $ \ logger -> do
bracket (startNode handlers opts addr logger) stopNode $ \ node ->
runDHT node action
{-# INLINE dht #-}
{-----------------------------------------------------------------------
-- Bootstrapping
-----------------------------------------------------------------------}
-- Do not include the following hosts in the default bootstrap nodes list:
--
-- * "dht.aelitis.com" and "dht6.azureusplatform.com" - since
-- Azureus client have a different (and probably incompatible) DHT
-- protocol implementation.
--
-- * "router.utorrent.com" since it is just an alias to
-- "router.bittorrent.com".
-- | List of bootstrap nodes maintained by different bittorrent
-- software authors.
defaultBootstrapNodes :: [NodeAddr HostName]
defaultBootstrapNodes =
[ NodeAddr "router.bittorrent.com" 6881 -- by BitTorrent Inc.
-- doesn't work at the moment (use git blame) of commit
, NodeAddr "dht.transmissionbt.com" 6881 -- by Transmission project
]
-- TODO Multihomed hosts
-- | Resolve either a numeric network address or a hostname to a
-- numeric IP address of the node. Usually used to resolve
-- 'defaultBootstrapNodes' or 'Data.Torrent.tNodes' lists.
resolveHostName :: NodeAddr HostName -> IO (NodeAddr IPv4)
resolveHostName NodeAddr {..} = do
let hints = defaultHints { addrFamily = AF_INET, addrSocketType = Datagram }
-- getAddrInfo throws exception on empty list, so the pattern matching never fail
info : _ <- getAddrInfo (Just hints) (Just nodeHost) (Just (show nodePort))
case fromSockAddr (addrAddress info) of
Nothing -> error "resolveNodeAddr: impossible"
Just addr -> return addr
-- | One good node may be sufficient.
--
-- This operation do block, use
-- 'Control.Concurrent.Async.Lifted.async' if needed.
--
bootstrap :: Address ip => [NodeAddr ip] -> DHT ip ()
bootstrap startNodes = do
$(logInfoS) "bootstrap" "Start node bootstrapping"
nid <- asks thisNodeId
-- TODO filter duplicated in startNodes list
aliveNodes <- queryParallel (pingQ <$> startNodes)
_ <- sourceList [aliveNodes] $= search nid (findNodeQ nid) $$ C.consume
$(logInfoS) "bootstrap" "Node bootstrapping finished"
-- | Check if this node is already bootstrapped.
-- @bootstrap [good_node] >> isBootstrapped@@ should always return 'True'.
--
-- This operation do not block.
--
isBootstrapped :: DHT ip Bool
isBootstrapped = T.full <$> getTable
{-----------------------------------------------------------------------
-- Initialization
-----------------------------------------------------------------------}
-- | Load previous session. (corrupted - exception/ignore ?)
--
-- This is blocking operation, use
-- 'Control.Concurrent.Async.Lifted.async' if needed.
restore :: ByteString -> DHT ip ()
restore = error "DHT.restore: not implemented"
-- | Serialize current DHT session to byte string.
--
-- This is blocking operation, use
-- 'Control.Concurrent.Async.Lifted.async' if needed.
snapshot :: DHT ip ByteString
snapshot = error "DHT.snapshot: not implemented"
{-----------------------------------------------------------------------
-- Operations
-----------------------------------------------------------------------}
-- | Get list of peers which downloading this torrent.
--
-- This operation is incremental and do block.
--
lookup :: Address ip => InfoHash -> DHT ip `Source` [PeerAddr ip]
lookup topic = do -- TODO retry getClosest if bucket is empty
closest <- lift $ getClosest topic
sourceList [closest] $= search topic (getPeersQ topic)
-- | Announce that /this/ peer may have some pieces of the specified
-- torrent. DHT will reannounce this data periodically using
-- 'optReannounce' interval.
--
-- This operation is synchronous and do block, use
-- 'Control.Concurrent.Async.Lifted.async' if needed.
--
insert :: Address ip => InfoHash -> PortNumber -> DHT ip ()
insert ih p = do
publish ih p
insertTopic ih p
-- | Stop announcing /this/ peer for the specified torrent.
--
-- This operation is atomic and may block for a while.
--
delete :: Address ip => InfoHash -> PortNumber -> DHT ip ()
delete = deleteTopic
{-# INLINE delete #-}
|
