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|
module Pairing (
PairingService(..),
PairingState(..),
PairingAttributes(..),
PairingResult(..),
pairingRequest,
) where
import Control.Monad.Except
import Control.Monad.Reader
import Crypto.Random
import Data.Bits
import Data.ByteArray (Bytes, convert)
import qualified Data.ByteArray as BA
import qualified Data.ByteString.Char8 as BC
import Data.Maybe
import qualified Data.Text as T
import Data.Typeable
import Data.Word
import Identity
import Network
import Service
import State
import Storage
data PairingService a = PairingRequest RefDigest
| PairingResponse Bytes
| PairingRequestNonce Bytes
| PairingAccept a
| PairingDecline
data PairingState a = NoPairing
| OurRequest Bytes
| OurRequestConfirm (Maybe a)
| OurRequestReady
| PeerRequest Bytes RefDigest
| PeerRequestConfirm
| PairingDone
| PairingFailed
data PairingAttributes a = PairingAttributes
{ pairingHookRequest :: ServiceHandler (PairingService a) ()
, pairingHookResponse :: String -> ServiceHandler (PairingService a) ()
, pairingHookRequestNonce :: String -> ServiceHandler (PairingService a) ()
, pairingHookRequestNonceFailed :: ServiceHandler (PairingService a) ()
, pairingHookConfirm :: a -> ServiceHandler (PairingService a) (Maybe a)
, pairingHookAccept :: a -> ServiceHandler (PairingService a) ()
}
class (Typeable a, Storable a) => PairingResult a where
pairingServiceID :: proxy a -> ServiceID
defaultPairingAttributes :: proxy (PairingService a) -> PairingAttributes a
instance Storable a => Storable (PairingService a) where
store' (PairingRequest x) = storeRec $ storeBinary "request" x
store' (PairingResponse x) = storeRec $ storeBinary "response" x
store' (PairingRequestNonce x) = storeRec $ storeBinary "reqnonce" x
store' (PairingAccept x) = store' x
store' (PairingDecline) = storeRec $ storeText "decline" ""
load' = do
res <- loadRec $ do
(req :: Maybe Bytes) <- loadMbBinary "request"
rsp <- loadMbBinary "response"
rnonce <- loadMbBinary "reqnonce"
(decline :: Maybe T.Text) <- loadMbText "decline"
return $ catMaybes
[ PairingRequest <$> (refDigestFromByteString =<< req)
, PairingResponse <$> rsp
, PairingRequestNonce <$> rnonce
, const PairingDecline <$> decline
]
case res of
x:_ -> return x
[] -> PairingAccept <$> load'
instance PairingResult a => Service (PairingService a) where
serviceID _ = pairingServiceID @a Proxy
type ServiceAttributes (PairingService a) = PairingAttributes a
defaultServiceAttributes = defaultPairingAttributes
type ServiceState (PairingService a) = PairingState a
emptyServiceState _ = NoPairing
serviceHandler spacket = ((,fromStored spacket) <$> svcGet) >>= \case
(NoPairing, PairingRequest confirm) -> do
join $ asks $ pairingHookRequest . svcAttributes
nonce <- liftIO $ getRandomBytes 32
svcSet $ PeerRequest nonce confirm
replyPacket $ PairingResponse nonce
(NoPairing, _) -> return ()
(OurRequest nonce, PairingResponse pnonce) -> do
peer <- asks $ svcPeerIdentity
self <- maybe (throwError "failed to validate own identity") return .
validateIdentity . lsIdentity . fromStored =<< svcGetLocal
hook <- asks $ pairingHookResponse . svcAttributes
hook $ confirmationNumber $ nonceDigest self peer nonce pnonce
svcSet $ OurRequestConfirm Nothing
replyPacket $ PairingRequestNonce nonce
(OurRequest _, _) -> do
svcSet $ PairingFailed
replyPacket PairingDecline
(OurRequestConfirm _, PairingAccept x) -> do
hook <- asks $ pairingHookConfirm . svcAttributes
(svcSet . OurRequestConfirm =<< hook x) `catchError` \_ -> do
svcSet $ PairingFailed
replyPacket PairingDecline
(OurRequestConfirm _, _) -> do
svcSet $ PairingFailed
replyPacket PairingDecline
(OurRequestReady, PairingAccept x) -> do
hook <- asks $ pairingHookAccept . svcAttributes
hook x `catchError` \_ -> do
svcSet $ PairingFailed
replyPacket PairingDecline
(OurRequestReady, _) -> do
svcSet $ PairingFailed
replyPacket PairingDecline
(PeerRequest nonce dgst, PairingRequestNonce pnonce) -> do
peer <- asks $ svcPeerIdentity
self <- maybe (throwError "failed to verify own identity") return .
validateIdentity . lsIdentity . fromStored =<< svcGetLocal
if dgst == nonceDigest peer self pnonce BA.empty
then do hook <- asks $ pairingHookRequestNonce . svcAttributes
hook $ confirmationNumber $ nonceDigest peer self pnonce nonce
svcSet PeerRequestConfirm
else do join $ asks $ pairingHookRequestNonceFailed . svcAttributes
svcSet PairingFailed
replyPacket PairingDecline
(PeerRequest _ _, _) -> do
svcSet $ PairingFailed
replyPacket PairingDecline
(PeerRequestConfirm, _) -> do
svcSet $ PairingFailed
replyPacket PairingDecline
(PairingDone, _) -> return ()
(PairingFailed, _) -> return ()
nonceDigest :: UnifiedIdentity -> UnifiedIdentity -> Bytes -> Bytes -> RefDigest
nonceDigest id1 id2 nonce1 nonce2 = hashToRefDigest $ serializeObject $ Rec
[ (BC.pack "id", RecRef $ storedRef $ idData id1)
, (BC.pack "id", RecRef $ storedRef $ idData id2)
, (BC.pack "nonce", RecBinary $ convert nonce1)
, (BC.pack "nonce", RecBinary $ convert nonce2)
]
confirmationNumber :: RefDigest -> String
confirmationNumber dgst = let (a:b:c:d:_) = map fromIntegral $ BA.unpack dgst :: [Word32]
str = show $ ((a `shift` 24) .|. (b `shift` 16) .|. (c `shift` 8) .|. d) `mod` (10 ^ len)
in replicate (len - length str) '0' ++ str
where len = 6
pairingRequest :: forall a m proxy. (PairingResult a, MonadIO m, MonadError String m) => proxy a -> Peer -> m ()
pairingRequest _ peer = do
self <- liftIO $ serverIdentity $ peerServer peer
nonce <- liftIO $ getRandomBytes 32
pid <- peerIdentity peer >>= \case
PeerIdentityFull pid -> return pid
_ -> throwError "incomplete peer identity"
sendToPeerWith @(PairingService a) peer $ \case
NoPairing -> return (Just $ PairingRequest (nonceDigest self pid nonce BA.empty), OurRequest nonce)
_ -> throwError "alredy in progress"
|