diff options
Diffstat (limited to 'Network/EBus/Layer2.hs')
| -rw-r--r-- | Network/EBus/Layer2.hs | 84 |
1 files changed, 67 insertions, 17 deletions
diff --git a/Network/EBus/Layer2.hs b/Network/EBus/Layer2.hs index b194ee6..04d652c 100644 --- a/Network/EBus/Layer2.hs +++ b/Network/EBus/Layer2.hs @@ -1,9 +1,17 @@ module Network.EBus.Layer2( ebusParserLayer2, - EbusPacket) where + EbusPacket, + ebusPacketType, + ebusPacketSource, + ebusPacketDestination, + ebusPacketPrimaryCommand, + ebusPacketSecondaryCommand, + ebusPacketPayload, + ebusPacketPayloadSlave) where import Control.Applicative ((<|>)) import Data.Attoparsec (anyWord8, count, skipMany, try, Parser, word8) +import Data.Bits (xor) import Data.Word (Word8) -- | Ebus Layer2 Constants @@ -22,7 +30,7 @@ data EbusType = EbusBroadcast | EbusMasterSlave deriving (Show) --- | Ebus Packet representation +-- | Ebus Packet data EbusPacket = EbusPacket { ebusPacketType :: EbusType, ebusPacketSource :: Word8, @@ -35,12 +43,12 @@ data EbusPacket = EbusPacket { -- | Ebus Binary Escape Sequences for payload data parserPayload :: Parser Word8 -parserPayload = do{ word8 $ ebusConstant "ESCAPE" - ; word8 $ ebusConstant "ESCAPE_ESCAPE" +parserPayload = do{ _ <- word8 $ ebusConstant "ESCAPE" + ; _ <- word8 $ ebusConstant "ESCAPE_ESCAPE" ; return $ ebusConstant "ESCAPE"} <|> - do{ word8 $ ebusConstant "ESCAPE" - ; word8 $ ebusConstant "ESCAPE_SYN" + do{ _ <- word8 $ ebusConstant "ESCAPE" + ; _ <- word8 $ ebusConstant "ESCAPE_SYN" ; return $ ebusConstant "SYN"} <|> anyWord8; @@ -59,9 +67,11 @@ ebusParserLayer2 = do{ if destination == 0xfe then -- Broadcast do{ crc <- anyWord8 - ; {- syn -} word8 $ ebusConstant "SYN" - ; if True then -- CHECK CRC - return $ EbusPacket EbusMasterMaster source destination primaryCommand secondaryCommand payload Nothing + ; _ <- {- syn -} word8 $ ebusConstant "SYN" + ; if ebusCrc ([source, destination, + primaryCommand, secondaryCommand, payloadLength] + ++ payload) == crc then + return $ EbusPacket EbusBroadcast source destination primaryCommand secondaryCommand payload Nothing else fail "Broadcast: CRC Check failed"} <|> @@ -70,9 +80,11 @@ ebusParserLayer2 = do{ -- Master-Master try( do{ crc <- anyWord8 - ; {- ack -} word8 $ ebusConstant "ACK" - ; {- syn -} word8 $ ebusConstant "SYN" - ; if True then -- CHECK CRC + ; _ <- {- ack -} word8 $ ebusConstant "ACK" + ; _ <- {- syn -} word8 $ ebusConstant "SYN" + ; if ebusCrc ([source, destination, + primaryCommand, secondaryCommand, payloadLength] + ++ payload) == crc then return $ EbusPacket EbusMasterMaster source destination primaryCommand secondaryCommand payload Nothing else fail "Master-Master: CRC Check failed"}) @@ -80,13 +92,16 @@ ebusParserLayer2 = do{ -- Master Slave try( do{ crc <- anyWord8 - ; {- ack -} word8 $ ebusConstant "ACK" + ; _ <- {- ack -} word8 $ ebusConstant "ACK" ; payloadSlaveLength <- anyWord8 ; payloadSlave <- count (fromIntegral payloadSlaveLength) parserPayload ; crcSlave <- anyWord8 - ; {- ackSlave -} word8 $ ebusConstant "ACK" - ; {- synSlave -} word8 $ ebusConstant "SYN" - ; if True then -- Check CRC + ; _ <- {- ackSlave -} word8 $ ebusConstant "ACK" + ; _ <- {- synSlave -} word8 $ ebusConstant "SYN" + ; if ebusCrc ([source, destination, + primaryCommand, secondaryCommand, payloadLength] + ++ payload) == crc && + ebusCrc ([payloadSlaveLength] ++ payloadSlave) == crcSlave then return $ EbusPacket EbusMasterSlave source destination primaryCommand secondaryCommand payload (Just payloadSlave) else fail "Master-Slave: CRC Check failed"}) @@ -95,4 +110,39 @@ ebusParserLayer2 = do{ fail "Failed to parse Master-Master/Master-Slave Packet" ; return followup <|> fail "Failed to parse packet" - }
\ No newline at end of file + } + +-- | Ebus CRC Calculation using a Table of precalculated values +ebusCrc :: [Word8] -> Word8 +ebusCrc input = foldl step 0 input + where step acc x = (crctab (fromIntegral acc)) `xor` x + +-- | Table for CRC Calculation +crctab :: Int -> Word8 +crctab pos = [ + 0, 155, 173, 54, 193, 90, 108, 247, 25, 130, --0 -9 + 180, 47, 216, 67, 117, 238, 50, 169, 159, 4, --10-19 + 243, 104, 94, 197, 43, 176, 134, 29, 234, 113, --20 + 71, 220, 100, 255, 201, 82, 165, 62, 8, 147, --30 + 125, 230, 208, 75, 188, 39, 17, 138, 86, 205, + 251, 96, 151, 12, 58, 161, 79, 212, 226, 121, + 142, 21, 35, 184, 200, 83, 101, 254, 9, 146, + 164, 63, 209, 74, 124, 231, 16, 139, 189, 38, + 250, 97, 87, 204, 59, 160, 150, 13, 227, 120, + 78, 213, 34, 185, 143, 20, 172, 55, 1, 154, + 109, 246, 192, 91, 181, 46, 24, 131, 116, 239, --100 + 217, 66, 158, 5, 51, 168, 95, 196, 242, 105, + 135, 28, 42, 177, 70, 221, 235, 112, 11, 144, + 166, 61, 202, 81, 103, 252, 18, 137, 191, 36, + 211, 72, 126, 229, 57, 162, 148, 15, 248, 99, + 85, 206, 32, 187, 141, 22, 225, 122, 76, 215, + 111, 244, 194, 89, 174, 53, 3, 152, 118, 237, + 219, 64, 183, 44, 26, 129, 93, 198, 240, 107, + 156, 7, 49, 170, 68, 223, 233, 114, 133, 30, + 40, 179, 195, 88, 110, 245, 2, 153, 175, 52, + 218, 65, 119, 236, 27, 128, 182, 45, 241, 106, --200 + 92, 199, 48, 171, 157, 6, 232, 115, 69, 222, + 41, 178, 132, 31, 167, 60, 10, 145, 102, 253, + 203, 80, 190, 37, 19, 136, 127, 228, 210, 73, + 149, 14, 56, 163, 84, 207, 249, 98, 140, 23, + 33, 186, 77, 214, 224, 123] !! pos
\ No newline at end of file |