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| Original file line number | Diff line number | Diff line change |
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| @@ -1,152 +1,55 @@ | ||
| {-| | ||
| Module : Clash.Cores.Arp.ArpTable | ||
| Description : Provides a highly configurable ARP table. | ||
| -} | ||
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| {-# language FlexibleContexts #-} | ||
| {-# language RecordWildCards #-} | ||
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| {-| | ||
| Module : Clash.Cores.Ethernet.Arp.ArpTable | ||
| Description : Provides an ARP table which is able to hold one ARP entry. | ||
| -} | ||
| module Clash.Cores.Ethernet.Arp.ArpTable | ||
| ( arpTable | ||
| ) where | ||
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| import Clash.Prelude | ||
| import Clash.Signal.Extra | ||
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| import Protocols | ||
| import Protocols.Df qualified as Df | ||
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| import Clash.Cores.Ethernet.Arp.ArpTypes | ||
| import Clash.Cores.Ethernet.IP.IPv4Types | ||
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| import Data.Maybe | ||
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| data ArpTableState depth | ||
| = Active { | ||
| -- | Whether the output of the blockram contains valid data | ||
| _bramValid :: Bool | ||
| } | ||
| -- ^ The ARP table is handling insertion and lookup requests | ||
| | Invalidating { | ||
| -- | The timer of the entry at this address will be decremented | ||
| _writeAddr :: Unsigned depth | ||
| } | ||
| -- ^ The ARP table is decrementing the timers of all entries, | ||
| -- and therefore cannot currently accept any insertion or lookup requests. | ||
| deriving (Generic, Show, ShowX, NFDataX) | ||
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| arpTableT | ||
| :: forall | ||
| (depth :: Nat) | ||
| (maxAgeSeconds :: Nat) | ||
| . KnownNat depth | ||
| => KnownNat maxAgeSeconds | ||
| => 1 <= maxAgeSeconds | ||
| => 1 <= depth | ||
| => depth <= 32 | ||
| => ArpTableState depth | ||
| -> ( Bool | ||
| , (ArpEntry, Index (maxAgeSeconds + 1)) | ||
| , Maybe (ArpEntry, Unsigned depth) | ||
| , Maybe (IPv4Address, Unsigned depth) | ||
| , Bool | ||
| ) | ||
| -> ( ArpTableState depth | ||
| , ( Ack | ||
| , Unsigned depth | ||
| , Maybe (Unsigned depth, (ArpEntry, Index (maxAgeSeconds + 1))) | ||
| , Maybe ArpResponse | ||
| ) | ||
| ) | ||
| -- If the reset is enabled, go back to the initial state | ||
| -- and don't acknowledge or send out data. | ||
| arpTableT _ (True, _, _, _, _) = | ||
| (Active False, (Ack False, 0, Nothing, Nothing)) | ||
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| arpTableT Active{..} (_, (arpEntry, secsLeft), insertionWithHash, lookupWithHash, secondPassed) | ||
| = (nextSt, (Ack True, readAddr, writeCmd, arpResponseOut)) | ||
| where | ||
| writeCmd = (\(entry, hash) -> (hash, (entry, maxBound))) <$> insertionWithHash | ||
| validLookup = isJust lookupWithHash | ||
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| arpResponseOut | ||
| | _bramValid && validLookup = Just (arpResponse (fst $ fromJustX lookupWithHash)) | ||
| | otherwise = Nothing | ||
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| -- It is possible that the IP stored in the entry is not the same as the lookup IP. | ||
| -- This happens due to hash collisions. | ||
| arpResponse lookupIP = | ||
| if secsLeft == 0 || lookupIP /= _arpIP arpEntry | ||
| then ArpEntryNotFound | ||
| else ArpEntryFound (_arpMac arpEntry) | ||
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| (nextSt, readAddr) | ||
| | secondPassed = (Invalidating maxBound, maxBound) | ||
| | otherwise = (Active (validLookup && not _bramValid), maybe 0 snd lookupWithHash) | ||
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| arpTableT Invalidating{..} (_, (arpEntry, secsLeft), _, _, _) | ||
| = (nextSt, (Ack False, readAddr, writeCmd, Nothing)) | ||
| where | ||
| writeCmd = Just (_writeAddr, (arpEntry, satPred SatBound secsLeft)) | ||
| (nextSt, readAddr) | ||
| | _writeAddr == 0 = (Active False, 0) | ||
| | otherwise = let addr = pred _writeAddr in (Invalidating addr, addr) | ||
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| -- | ARP table that stores @2^depth@ entries in block ram. `maxAgeSeconds` is the number of seconds before the | ||
| -- entry will be removed from the table (lazily). The timeout is inaccurate for up to one second, because | ||
| -- the circuit uses a constant counter for efficiency. Every second, the ARP table is unable to handle insertion | ||
| -- and lookup requests for @2^depth@ clock cycles, because it needs to decrease the timers of the entries. | ||
| -- During this period, the component will assert backpressure. Note that this implies that the component will | ||
| -- not work correctly when the size of the ARP table is bigger than the clock frequency. | ||
| -- | ||
| -- An entry may be evicted sooner than expected from the cache due to hash collisions; entries are addressed | ||
| -- by taking the last `depth` bits of their corresponding IPv4 address. By increasing the | ||
| -- number of entries in the table, the chance of IPv4 addresses colliding is lower. | ||
| -- | ARP table that stores one ARP entry in a register. `maxAgeSeconds` is the number of seconds before the | ||
| -- entry will be removed from the table (lazily). The timeout is inaccurate for up to one second less, because | ||
| -- the circuit uses a constant counter for efficiency reasons. For example, when `maxAgeSeconds` is set to 30, | ||
| -- an entry will expire in 29-30 seconds. The clock frequency must be at least 1 Hz for timeouts to work correctly. | ||
| arpTable | ||
| :: forall | ||
| (dom :: Domain) | ||
| (depth :: Nat) | ||
| (maxAgeSeconds :: Nat) | ||
| (dom :: Domain) | ||
| (maxAgeSeconds :: Nat) | ||
| . HiddenClockResetEnable dom | ||
| => KnownDomain dom | ||
| => 1 <= DomainPeriod dom | ||
| => DomainPeriod dom <= 5 * 10^11 | ||
| => KnownNat (DomainPeriod dom) | ||
| => 1 <= DomainPeriod dom | ||
| => DomainPeriod dom <= 10^12 | ||
| => 1 <= maxAgeSeconds | ||
| => 1 <= depth | ||
| => depth <= 32 | ||
| => SNat depth | ||
| -- ^ Determines the number of entries in the ARP table, namely @2^depth@. | ||
| -> SNat maxAgeSeconds | ||
| -- ^ Entries are no longer valid after this number of seconds, starting at the time of insertion. | ||
| => SNat maxAgeSeconds | ||
| -- ^ The ARP entry will expire after this many seconds | ||
| -> Circuit (ArpLookup dom, Df dom ArpEntry) () | ||
| -- ^ First of LHS is a MAC lookup request for that IPv4 address. | ||
| -- Second of LHS is an insertion request. | ||
| arpTable SNat SNat = Circuit (hideReset ckt) | ||
| -- ^ First of LHS is a MAC address request for the given IPv4 address. Second of LHS is an insertion request | ||
| arpTable SNat = fromSignals ckt | ||
| where | ||
| ckt reset ((lookupReq, insertReq), ()) = ((arpResponse, outReady), ()) | ||
| ckt ((lookupReq, insertReq), ()) = ((arpResponse, pure (Ack True)), ()) | ||
| where | ||
| -- The underlying blockram. | ||
| tableEntry = blockRam1 NoClearOnReset (SNat @(2^depth)) (errorX "", 0) readAddr writeCmd | ||
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| -- Hashes of the IPv4 addresses, used to address the blockram. | ||
| -- We simply take the last `depth` bits of the IPv4 address. | ||
| lookupWithHash :: Signal dom (Maybe (IPv4Address, Unsigned depth)) | ||
| lookupWithHash = fmap (\ipAddr -> (ipAddr, resize $ bitCoerce ipAddr)) <$> lookupReq | ||
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| insertionWithHash :: Signal dom (Maybe (ArpEntry, Unsigned depth)) | ||
| insertionWithHash = fmap (\entry -> (entry, resize $ bitCoerce (_arpIP entry))) <$> fmap Df.dataToMaybe insertReq | ||
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| readAddr :: Signal dom (Unsigned depth) | ||
| writeCmd :: Signal dom (Maybe (Unsigned depth, (ArpEntry, Index (maxAgeSeconds + 1)))) | ||
| (outReady, readAddr, writeCmd, arpResponse) = | ||
| unbundle (mealy arpTableT (Active False) input) | ||
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| input = bundle | ||
| ( unsafeToActiveHigh reset | ||
| , tableEntry | ||
| , insertionWithHash | ||
| , lookupWithHash | ||
| , secondTimer | ||
| ) | ||
| arpEntry :: Signal dom (ArpEntry, Index (maxAgeSeconds + 1)) | ||
| arpEntry = register (errorX "empty initial content", 0) writeCommand | ||
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| secondTimer = riseEvery (SNat @(10^12 `Div` DomainPeriod dom)) | ||
| writeCommand = fmap go (bundle (insertReq, arpEntry, secondTimer)) | ||
| where | ||
| go (req, (entry, secondsLeft), secondPassed) = case req of | ||
| Df.NoData -> (entry, if secondPassed then satPred SatBound secondsLeft else secondsLeft) | ||
| Df.Data reqEntry -> (reqEntry, maxBound) | ||
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| arpResponse = fmap go (bundle (lookupReq, arpEntry)) | ||
| where | ||
| go (ip, (entry, timeLeft)) = ip >>= \ipAddr -> | ||
| if timeLeft == 0 || _arpIP entry /= ipAddr | ||
| then Just ArpEntryNotFound | ||
| else Just (ArpEntryFound (_arpMac entry)) |
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