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module Pairing (
PairingService(..),
PairingState(..),
PairingAttributes(..),
PairingResult(..),
pairingRequest,
pairingAccept,
pairingReject,
) 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.Kind
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
| PairingReject
data PairingState a = NoPairing
| OurRequest Bytes
| OurRequestConfirm (Maybe (PairingVerifiedResult a))
| OurRequestReady
| PeerRequest Bytes RefDigest
| PeerRequestConfirm
| PairingDone
data PairingAttributes a = PairingAttributes
{ pairingHookRequest :: ServiceHandler (PairingService a) ()
, pairingHookResponse :: String -> ServiceHandler (PairingService a) ()
, pairingHookRequestNonce :: String -> ServiceHandler (PairingService a) ()
, pairingHookRequestNonceFailed :: ServiceHandler (PairingService a) ()
, pairingHookConfirmedResponse :: ServiceHandler (PairingService a) ()
, pairingHookConfirmedRequest :: ServiceHandler (PairingService a) ()
, pairingHookAcceptedResponse :: ServiceHandler (PairingService a) ()
, pairingHookAcceptedRequest :: ServiceHandler (PairingService a) ()
, pairingHookVerifyFailed :: ServiceHandler (PairingService a) ()
, pairingHookRejected :: ServiceHandler (PairingService a) ()
, pairingHookFailed :: ServiceHandler (PairingService a) ()
}
class (Typeable a, Storable a) => PairingResult a where
type PairingVerifiedResult a :: Type
type PairingVerifiedResult a = a
pairingServiceID :: proxy a -> ServiceID
pairingVerifyResult :: a -> ServiceHandler (PairingService a) (Maybe (PairingVerifiedResult a))
pairingFinalizeRequest :: PairingVerifiedResult a -> ServiceHandler (PairingService a) ()
pairingFinalizeResponse :: ServiceHandler (PairingService a) a
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' (PairingReject) = storeRec $ storeText "reject" ""
load' = do
res <- loadRec $ do
(req :: Maybe Bytes) <- loadMbBinary "request"
rsp <- loadMbBinary "response"
rnonce <- loadMbBinary "reqnonce"
(rej :: Maybe T.Text) <- loadMbText "reject"
return $ catMaybes
[ PairingRequest <$> (refDigestFromByteString =<< req)
, PairingResponse <$> rsp
, PairingRequestNonce <$> rnonce
, const PairingReject <$> rej
]
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 ()
(PairingDone, _) -> return ()
(_, PairingReject) -> do
join $ asks $ pairingHookRejected . svcAttributes
svcSet NoPairing
(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 _, _) -> reject
(OurRequestConfirm _, PairingAccept x) -> do
flip catchError (const reject) $ do
pairingVerifyResult x >>= \case
Just x' -> do
join $ asks $ pairingHookConfirmedRequest . svcAttributes
svcSet $ OurRequestConfirm (Just x')
Nothing -> do
join $ asks $ pairingHookVerifyFailed . svcAttributes
svcSet NoPairing
replyPacket PairingReject
(OurRequestConfirm _, _) -> reject
(OurRequestReady, PairingAccept x) -> do
flip catchError (const reject) $ do
pairingVerifyResult x >>= \case
Just x' -> do
pairingFinalizeRequest x'
join $ asks $ pairingHookAcceptedResponse . svcAttributes
svcSet $ PairingDone
Nothing -> do
join $ asks $ pairingHookVerifyFailed . svcAttributes
throwError ""
(OurRequestReady, _) -> reject
(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 NoPairing
replyPacket PairingReject
(PeerRequest _ _, _) -> reject
(PeerRequestConfirm, _) -> reject
reject :: PairingResult a => ServiceHandler (PairingService a) ()
reject = do
join $ asks $ pairingHookFailed . svcAttributes
svcSet NoPairing
replyPacket PairingReject
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 "already in progress"
pairingAccept :: forall a m proxy. (PairingResult a, MonadIO m, MonadError String m) => proxy a -> Peer -> m ()
pairingAccept _ peer = runPeerService @(PairingService a) peer $ do
svcGet >>= \case
NoPairing -> throwError $ "none in progress"
OurRequest {} -> throwError $ "waiting for peer"
OurRequestConfirm Nothing -> do
join $ asks $ pairingHookConfirmedResponse . svcAttributes
svcSet OurRequestReady
OurRequestConfirm (Just verified) -> do
join $ asks $ pairingHookAcceptedResponse . svcAttributes
pairingFinalizeRequest verified
svcSet PairingDone
OurRequestReady -> throwError $ "already accepted, waiting for peer"
PeerRequest {} -> throwError $ "waiting for peer"
PeerRequestConfirm -> do
join $ asks $ pairingHookAcceptedRequest . svcAttributes
replyPacket . PairingAccept =<< pairingFinalizeResponse
svcSet PairingDone
PairingDone -> throwError $ "already done"
pairingReject :: forall a m proxy. (PairingResult a, MonadIO m, MonadError String m) => proxy a -> Peer -> m ()
pairingReject _ peer = runPeerService @(PairingService a) peer $ do
svcGet >>= \case
NoPairing -> throwError $ "none in progress"
PairingDone -> throwError $ "already done"
_ -> reject
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