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module Erebos.Discovery (
DiscoveryService(..),
DiscoveryConnection(..)
) where
import Control.Concurrent
import Control.Monad.Except
import Control.Monad.Reader
import Data.Map.Strict (Map)
import qualified Data.Map.Strict as M
import Data.Maybe
import Data.Text (Text)
import qualified Data.Text as T
import Network.Socket
import Erebos.ICE
import Erebos.Identity
import Erebos.Network
import Erebos.Service
import Erebos.Storage
keepaliveSeconds :: Int
keepaliveSeconds = 20
data DiscoveryService = DiscoverySelf Text Int
| DiscoveryAcknowledged Text
| DiscoverySearch Ref
| DiscoveryResult Ref (Maybe Text)
| DiscoveryConnectionRequest DiscoveryConnection
| DiscoveryConnectionResponse DiscoveryConnection
data DiscoveryConnection = DiscoveryConnection
{ dconnSource :: Ref
, dconnTarget :: Ref
, dconnAddress :: Maybe Text
, dconnIceSession :: Maybe IceRemoteInfo
}
emptyConnection :: Ref -> Ref -> DiscoveryConnection
emptyConnection source target = DiscoveryConnection source target Nothing Nothing
instance Storable DiscoveryService where
store' x = storeRec $ do
case x of
DiscoverySelf addr priority -> do
storeText "self" addr
storeInt "priority" priority
DiscoveryAcknowledged addr -> do
storeText "ack" addr
DiscoverySearch ref -> storeRawRef "search" ref
DiscoveryResult ref addr -> do
storeRawRef "result" ref
storeMbText "address" addr
DiscoveryConnectionRequest conn -> storeConnection "request" conn
DiscoveryConnectionResponse conn -> storeConnection "response" conn
where storeConnection ctype conn = do
storeText "connection" $ ctype
storeRawRef "source" $ dconnSource conn
storeRawRef "target" $ dconnTarget conn
storeMbText "address" $ dconnAddress conn
storeMbRef "ice-session" $ dconnIceSession conn
load' = loadRec $ msum
[ DiscoverySelf
<$> loadText "self"
<*> loadInt "priority"
, DiscoveryAcknowledged
<$> loadText "ack"
, DiscoverySearch <$> loadRawRef "search"
, DiscoveryResult
<$> loadRawRef "result"
<*> loadMbText "address"
, loadConnection "request" DiscoveryConnectionRequest
, loadConnection "response" DiscoveryConnectionResponse
]
where loadConnection ctype ctor = do
ctype' <- loadText "connection"
guard $ ctype == ctype'
return . ctor =<< DiscoveryConnection
<$> loadRawRef "source"
<*> loadRawRef "target"
<*> loadMbText "address"
<*> loadMbRef "ice-session"
data DiscoveryPeer = DiscoveryPeer
{ dpPriority :: Int
, dpPeer :: Maybe Peer
, dpAddress :: Maybe Text
, dpIceSession :: Maybe IceSession
}
instance Service DiscoveryService where
serviceID _ = mkServiceID "dd59c89c-69cc-4703-b75b-4ddcd4b3c23b"
type ServiceGlobalState DiscoveryService = Map RefDigest DiscoveryPeer
emptyServiceGlobalState _ = M.empty
serviceHandler msg = case fromStored msg of
DiscoverySelf addr priority -> do
pid <- asks svcPeerIdentity
peer <- asks svcPeer
let insertHelper new old | dpPriority new > dpPriority old = new
| otherwise = old
mbaddr <- case words (T.unpack addr) of
[ipaddr, port] | DatagramAddress paddr <- peerAddress peer -> do
saddr <- liftIO $ head <$> getAddrInfo (Just $ defaultHints { addrSocketType = Datagram }) (Just ipaddr) (Just port)
return $ if paddr == addrAddress saddr
then Just addr
else Nothing
_ -> return Nothing
forM_ (idDataF =<< unfoldOwners pid) $ \s ->
svcModifyGlobal $ M.insertWith insertHelper (refDigest $ storedRef s) $
DiscoveryPeer priority (Just peer) mbaddr Nothing
replyPacket $ DiscoveryAcknowledged $ fromMaybe (T.pack "ICE") mbaddr
DiscoveryAcknowledged addr -> do
when (addr == T.pack "ICE") $ do
-- keep-alive packet from behind NAT
peer <- asks svcPeer
liftIO $ void $ forkIO $ do
threadDelay (keepaliveSeconds * 1000 * 1000)
res <- runExceptT $ sendToPeer peer $ DiscoverySelf addr 0
case res of
Right _ -> return ()
Left err -> putStrLn $ "Discovery: failed to send keep-alive: " ++ err
DiscoverySearch ref -> do
addr <- M.lookup (refDigest ref) <$> svcGetGlobal
replyPacket $ DiscoveryResult ref $ fromMaybe (T.pack "ICE") . dpAddress <$> addr
DiscoveryResult ref Nothing -> do
svcPrint $ "Discovery: " ++ show (refDigest ref) ++ " not found"
DiscoveryResult ref (Just addr) -> do
-- TODO: check if we really requested that
server <- asks svcServer
if addr == T.pack "ICE"
then do
self <- svcSelf
peer <- asks svcPeer
ice <- liftIO $ iceCreate PjIceSessRoleControlling $ \ice -> do
rinfo <- iceRemoteInfo ice
res <- runExceptT $ sendToPeer peer $
DiscoveryConnectionRequest (emptyConnection (storedRef $ idData self) ref) { dconnIceSession = Just rinfo }
case res of
Right _ -> return ()
Left err -> putStrLn $ "Discovery: failed to send connection request: " ++ err
svcModifyGlobal $ M.insert (refDigest ref) $
DiscoveryPeer 0 Nothing Nothing (Just ice)
else do
case words (T.unpack addr) of
[ipaddr, port] -> do
saddr <- liftIO $ head <$>
getAddrInfo (Just $ defaultHints { addrSocketType = Datagram }) (Just ipaddr) (Just port)
peer <- liftIO $ serverPeer server (addrAddress saddr)
svcModifyGlobal $ M.insert (refDigest ref) $
DiscoveryPeer 0 (Just peer) Nothing Nothing
_ -> svcPrint $ "Discovery: invalid address in result: " ++ T.unpack addr
DiscoveryConnectionRequest conn -> do
self <- svcSelf
let rconn = emptyConnection (dconnSource conn) (dconnTarget conn)
if refDigest (dconnTarget conn) `elem` (map (refDigest . storedRef) $ idDataF =<< unfoldOwners self)
then do
-- request for us, create ICE sesssion
server <- asks svcServer
peer <- asks svcPeer
liftIO $ void $ iceCreate PjIceSessRoleControlled $ \ice -> do
rinfo <- iceRemoteInfo ice
res <- runExceptT $ sendToPeer peer $ DiscoveryConnectionResponse rconn { dconnIceSession = Just rinfo }
case res of
Right _ -> do
case dconnIceSession conn of
Just prinfo -> iceConnect ice prinfo $ void $ serverPeerIce server ice
Nothing -> putStrLn $ "Discovery: connection request without ICE remote info"
Left err -> putStrLn $ "Discovery: failed to send connection response: " ++ err
else do
-- request to some of our peers, relay
mbdp <- M.lookup (refDigest $ dconnTarget conn) <$> svcGetGlobal
case mbdp of
Nothing -> replyPacket $ DiscoveryConnectionResponse rconn
Just dp | Just addr <- dpAddress dp -> do
replyPacket $ DiscoveryConnectionResponse rconn { dconnAddress = Just addr }
| Just dpeer <- dpPeer dp -> do
sendToPeer dpeer $ DiscoveryConnectionRequest conn
| otherwise -> svcPrint $ "Discovery: failed to relay connection request"
DiscoveryConnectionResponse conn -> do
self <- svcSelf
dpeers <- svcGetGlobal
if refDigest (dconnSource conn) `elem` (map (refDigest . storedRef) $ idDataF =<< unfoldOwners self)
then do
-- response to our request, try to connect to the peer
server <- asks svcServer
if | Just addr <- dconnAddress conn
, [ipaddr, port] <- words (T.unpack addr) -> do
saddr <- liftIO $ head <$>
getAddrInfo (Just $ defaultHints { addrSocketType = Datagram }) (Just ipaddr) (Just port)
peer <- liftIO $ serverPeer server (addrAddress saddr)
svcModifyGlobal $ M.insert (refDigest $ dconnTarget conn) $
DiscoveryPeer 0 (Just peer) Nothing Nothing
| Just dp <- M.lookup (refDigest $ dconnTarget conn) dpeers
, Just ice <- dpIceSession dp
, Just rinfo <- dconnIceSession conn -> do
liftIO $ iceConnect ice rinfo $ void $ serverPeerIce server ice
| otherwise -> svcPrint $ "Discovery: connection request failed"
else do
-- response to relayed request
case M.lookup (refDigest $ dconnSource conn) dpeers of
Just dp | Just dpeer <- dpPeer dp -> do
sendToPeer dpeer $ DiscoveryConnectionResponse conn
_ -> svcPrint $ "Discovery: failed to relay connection response"
|