shrub/pkg/hs/urbit-king/lib/Urbit/Vere/Ames.hs
2020-10-29 23:22:48 +01:00

349 lines
11 KiB
Haskell

{-|
Ames IO Driver
-}
module Urbit.Vere.Ames (ames, ames', PacketOutcome(..)) where
import Urbit.Prelude
import Network.Socket hiding (recvFrom, sendTo)
import Urbit.Arvo hiding (Fake)
import Urbit.King.Config
import Urbit.King.Scry
import Urbit.Vere.Ames.LaneCache
import Urbit.Vere.Ames.Packet
import Urbit.Vere.Pier.Types
import Urbit.Vere.Ports
import Data.Serialize (decode, encode)
import Urbit.King.App (HasKingId(..), HasPierEnv(..))
import Urbit.Vere.Ames.DNS (NetworkMode(..), ResolvServ(..))
import Urbit.Vere.Ames.DNS (galaxyPort, resolvServ)
import Urbit.Vere.Ames.UDP (UdpServ(..), fakeUdpServ, realUdpServ)
import qualified Urbit.Noun.Time as Time
-- Constants -------------------------------------------------------------------
-- | How many unprocessed ames packets to allow in the queue before we start
-- dropping incoming packets.
queueBound :: Word
queueBound = 1000
-- | How often, measured in number of packets dropped, we should announce packet
-- loss.
packetsDroppedPerComplaint :: Word
packetsDroppedPerComplaint = 1000
-- Types -----------------------------------------------------------------------
type Version = Word8
data AmesDrv = AmesDrv
{ aTurfs :: TVar (Maybe [Turf])
, aDropped :: TVar Word
, aVersion :: TVar (Maybe Version)
, aUdpServ :: UdpServ
, aResolvr :: ResolvServ
, aVersTid :: Async ()
, aRecvTid :: Async ()
}
data PacketOutcome
= Intake
| Ouster
-- Utils -----------------------------------------------------------------------
listenPort :: NetworkMode -> Ship -> PortNumber
listenPort m s | s < 256 = galaxyPort m (fromIntegral s)
listenPort m _ = 0 -- I don't care, just give me any port.
localhost :: HostAddress
localhost = tupleToHostAddress (127, 0, 0, 1)
inaddrAny :: HostAddress
inaddrAny = tupleToHostAddress (0, 0, 0, 0)
modeAddress :: NetworkMode -> Maybe HostAddress
modeAddress = \case
Fake -> Just localhost
Localhost -> Just localhost
Real -> Just inaddrAny
NoNetwork -> Nothing
okFakeAddr :: AmesDest -> Bool
okFakeAddr = \case
EachYes _ -> True
EachNo (Jammed (AAIpv4 (Ipv4 a) _)) -> a == localhost
EachNo (Jammed (AAVoid v )) -> absurd v
localAddr :: NetworkMode -> AmesDest -> SockAddr
localAddr mode = \case
EachYes g -> SockAddrInet (galaxyPort mode g) localhost
EachNo (Jammed (AAIpv4 _ p)) -> SockAddrInet (fromIntegral p) localhost
EachNo (Jammed (AAVoid v )) -> absurd v
bornEv :: KingId -> Ev
bornEv inst = EvBlip $ BlipEvNewt $ NewtEvBorn (fromIntegral inst, ()) ()
hearEv :: PortNumber -> HostAddress -> ByteString -> Ev
hearEv p a bs =
EvBlip $ BlipEvAmes $ AmesEvHear () (ipDest p a) (MkBytes bs)
ipDest :: PortNumber -> HostAddress -> AmesDest
ipDest p a = EachNo $ Jammed $ AAIpv4 (Ipv4 a) (fromIntegral p)
--------------------------------------------------------------------------------
netMode :: HasNetworkConfig e => Bool -> RIO e NetworkMode
netMode isFake = do
netMode <- view (networkConfigL . ncNetMode)
noAmes <- view (networkConfigL . ncNoAmes)
pure $ case (noAmes, isFake, netMode) of
(True, _ , _ ) -> NoNetwork
(_ , _ , NMNone ) -> NoNetwork
(_ , True, _ ) -> Fake
(_ , _ , NMNormal ) -> Real
(_ , _ , NMLocalhost) -> Localhost
udpPort :: HasNetworkConfig e => Bool -> Ship -> RIO e PortNumber
udpPort isFake who = do
mode <- netMode isFake
mPort <- view (networkConfigL . ncAmesPort)
pure $ maybe (listenPort mode who) fromIntegral mPort
udpServ :: (HasLogFunc e, HasNetworkConfig e, HasPortControlApi e)
=> Bool
-> Ship
-> RIO e UdpServ
udpServ isFake who = do
mode <- netMode isFake
port <- udpPort isFake who
case modeAddress mode of
Nothing -> fakeUdpServ
Just host -> realUdpServ port host
_bornFailed :: e -> WorkError -> IO ()
_bornFailed env _ = runRIO env $ do
pure () -- TODO What can we do?
ames'
:: HasPierEnv e
=> Ship
-> Bool
-> (Time.Wen -> Gang -> Path -> IO (Maybe (Term, Noun)))
-> (Text -> RIO e ())
-> RIO e ([Ev], RAcquire e (DriverApi NewtEf))
ames' who isFake scry stderr = do
-- Unfortunately, we cannot use TBQueue because the only behavior
-- provided for when full is to block the writer. The implementation
-- below uses materially the same data structures as TBQueue, however.
ventQ :: TQueue EvErr <- newTQueueIO
avail :: TVar Word <- newTVarIO queueBound
let
enqueuePacket p = do
vail <- readTVar avail
if vail > 0
then do
modifyTVar' avail (subtract 1)
writeTQueue ventQ p
pure Intake
else do
_ <- readTQueue ventQ
writeTQueue ventQ p
pure Ouster
dequeuePacket = do
pM <- tryReadTQueue ventQ
when (isJust pM) $ modifyTVar avail (+ 1)
pure pM
env <- ask
let (bornEvs, startDriver) = ames env who isFake scry enqueuePacket stderr
let runDriver = do
diOnEffect <- startDriver
let diEventSource = fmap RRWork <$> dequeuePacket
pure (DriverApi {..})
pure (bornEvs, runDriver)
{-|
inst -- Process instance number.
who -- Which ship are we?
enqueueEv -- Queue-event action.
mPort -- Explicit port override from command line arguments.
4096 is a reasonable number for recvFrom. Packets of that size are
not possible on the internet.
TODO verify that the KingIds match on effects.
-}
ames
:: forall e
. (HasLogFunc e, HasNetworkConfig e, HasPortControlApi e, HasKingId e)
=> e
-> Ship
-> Bool
-> (Time.Wen -> Gang -> Path -> IO (Maybe (Term, Noun)))
-> (EvErr -> STM PacketOutcome)
-> (Text -> RIO e ())
-> ([Ev], RAcquire e (NewtEf -> IO ()))
ames env who isFake scry enqueueEv stderr = (initialEvents, runAmes)
where
king = fromIntegral (env ^. kingIdL)
initialEvents :: [Ev]
initialEvents = [bornEv king]
runAmes :: RAcquire e (NewtEf -> IO ())
runAmes = do
mode <- rio (netMode isFake)
drv <- mkRAcquire start stop
pure (handleEffect drv mode)
start :: RIO e AmesDrv
start = do
mode <- rio (netMode isFake)
cachedScryLane <- cache scryLane
aTurfs <- newTVarIO Nothing
aDropped <- newTVarIO 0
aVersion <- newTVarIO Nothing
aVersTid <- trackVersionThread aVersion
aUdpServ <- udpServ isFake who
aResolvr <- resolvServ aTurfs (usSend aUdpServ) stderr
aRecvTid <- queuePacketsThread
aDropped
aVersion
cachedScryLane
(send aUdpServ aResolvr mode)
aUdpServ
pure (AmesDrv { .. })
hearFailed _ = pure ()
trackVersionThread :: HasLogFunc e => TVar (Maybe Version) -> RIO e (Async ())
trackVersionThread versSlot = async $ forever do
scryVersion >>= \case
Just v -> do
v0 <- readTVarIO versSlot
atomically $ writeTVar versSlot (Just v)
if (v0 == Just v)
then logInfo $ displayShow ("ames: proto version unchanged at", v)
else stderr ("ames: protocol version now " <> tshow v)
Nothing -> logError "ames: could not scry for version"
threadDelay (10 * 60 * 1_000_000) -- 10m
queuePacketsThread :: HasLogFunc e
=> TVar Word
-> TVar (Maybe Version)
-> (Ship -> RIO e (Maybe [AmesDest]))
-> (AmesDest -> ByteString -> RIO e ())
-> UdpServ
-> RIO e (Async ())
queuePacketsThread dropCtr vers lan forward UdpServ{..} = async $ forever $ do
-- port number, host address, bytestring
(p, a, b) <- atomically usRecv
ver <- readTVarIO vers
case decode b of
Right (pkt@Packet {..}) | ver == Nothing || ver == Just pktVersion -> do
logDebug $ displayShow ("ames: bon packet", pkt, showUD $ bytesAtom b)
if pktRcvr == who
then serfsUp p a b
else lan pktRcvr >>= \case
Just ls
| dest:_ <- filter notSelf ls
-> forward dest $ encode pkt
{ pktOrigin = pktOrigin <|> Just (ipDest p a) }
where
notSelf (EachYes g) = who /= Ship (fromIntegral g)
notSelf (EachNo _) = True
_ -> logInfo $ displayShow ("ames: dropping unroutable", pkt)
Right pkt -> logInfo $ displayShow ("ames: dropping ill-versed", pkt, ver)
-- XX better handle misversioned or illegible packets.
-- Remarks from 67f06ce5, pkg/urbit/vere/io/ames.c, L1010:
--
-- [There are] two protocol-change scenarios [which we must think about]:
--
-- - packets using old protocol versions from our sponsees
-- these must be let through, and this is a transitive condition;
-- they must also be forwarded where appropriate
-- they can be validated, as we know their semantics
--
-- - packets using newer protocol versions
-- these should probably be let through, or at least
-- trigger printfs suggesting upgrade.
-- they cannot be filtered, as we do not know their semantics
--
Left e -> logInfo $ displayShow ("ames: dropping malformed", e)
where
serfsUp p a b =
atomically (enqueueEv (EvErr (hearEv p a b) hearFailed)) >>= \case
Intake -> pure ()
Ouster -> do
d <- atomically $ do
d <- readTVar dropCtr
writeTVar dropCtr (d + 1)
pure d
when (d `rem` packetsDroppedPerComplaint == 0) $
logWarn "ames: queue full; dropping inbound packets"
stop :: forall e. AmesDrv -> RIO e ()
stop AmesDrv {..} = io $ do
usKill aUdpServ
rsKill aResolvr
cancel aVersTid
cancel aRecvTid
handleEffect :: AmesDrv -> NetworkMode -> NewtEf -> IO ()
handleEffect drv@AmesDrv {..} mode = runRIO env . \case
NewtEfTurf (_id, ()) turfs -> do
atomically $ writeTVar aTurfs (Just turfs)
NewtEfSend (_id, ()) dest (MkBytes bs) -> do
atomically (readTVar aTurfs) >>= \case
Nothing -> stderr "ames: send before turfs" >> pure ()
Just turfs -> send aUdpServ aResolvr mode dest bs
send :: UdpServ
-> ResolvServ
-> NetworkMode
-> AmesDest
-> ByteString
-> RIO e ()
send udpServ resolvr mode dest byt = do
let to adr = io (usSend udpServ adr byt)
case (mode, dest) of
(NoNetwork, _ ) -> pure ()
(Fake , _ ) -> when (okFakeAddr dest) $ to (localAddr Fake dest)
(Localhost, _ ) -> to (localAddr Localhost dest)
(Real , ra) -> ra & \case
EachYes gala -> io (rsSend resolvr gala byt)
EachNo addr -> to (ipv4Addr addr)
scryVersion :: HasLogFunc e => RIO e (Maybe Version)
scryVersion = scryNow scry "ax" who "" ["protocol", "version"]
scryLane :: HasLogFunc e
=> Ship
-> RIO e (Maybe [AmesDest])
scryLane ship = scryNow scry "ax" who "" ["peers", tshow ship, "forward-lane"]
ipv4Addr (Jammed (AAVoid v )) = absurd v
ipv4Addr (Jammed (AAIpv4 a p)) = SockAddrInet (fromIntegral p) (unIpv4 a)