Separated module CryptoTransport from ToxTransport.

1 files changed, 121 insertions, 0 deletions

diff --git a/CryptoTransport.hs b/CryptoTransport.hs
new file mode 100644
index 00000000..ddf1a558
--- /dev/null
+++ b/CryptoTransport.hs
@@ -0,0 +1,121 @@
+{-# LANGUAGE KindSignatures #-}
+module CryptoTransport
+    ( parseNetCrypto
+    , encodeNetCrypto
+    -- CryptoTransport
+    , NetCrypto(..)
+    , CryptoData(..)
+    , CryptoMessage(..)
+    , CryptoPacket(..)
+    , HandshakeData(..)
+    , Handshake(..)
+    ) where
+
+import ToxCrypto
+import DHTTransport (Cookie)
+
+import Network.Socket
+import Data.ByteString
+import Data.Word
+import Crypto.Hash
+
+data NetCrypto
+    = NetHandshake (Handshake Encrypted)
+    | NetCrypto (CryptoPacket Encrypted)
+
+parseNetCrypto :: ByteString -> SockAddr -> Either String (NetCrypto, SockAddr)
+parseNetCrypto = _todo
+
+encodeNetCrypto :: NetCrypto -> SockAddr -> (ByteString, SockAddr)
+encodeNetCrypto = _todo
+
+data Handshake (f :: * -> *) = Handshake
+    { handshakeCookie :: Cookie
+    , handshakeNonce :: Nonce24
+    , hadshakeData :: f HandshakeData
+    }
+
+data HandshakeData = HandshakeData
+    { baseNonce :: Nonce24
+    , sessionKey :: PublicKey
+    , cookieHash :: Digest SHA512
+    , otherCookie :: Cookie
+    }
+
+data CryptoPacket (f :: * -> *) = CryptoPacket
+    { pktNonce :: Word16
+    , pktData :: f CryptoData
+    }
+
+data CryptoData = CryptoData
+    { -- | [our recvbuffers buffer_start, (highest packet number handled + 1), (big endian)]
+      bufferStart :: Word32
+      -- | [  uint32_t packet number if lossless
+      --   , sendbuffer buffer_end  if lossy   , (big endian)]
+    , bufferEnd :: Word32
+      -- | [data]
+    , bufferData :: CryptoMessage
+    }
+
+-- TODO: Flesh this out.
+data CryptoMessage      -- First byte indicates data
+    = Padding           -- ^ 0 padding (skipped until we hit a non zero (data id) byte)
+    | PacketRequest     -- ^ 1 packet request packet (lossy packet)
+    | KillPacket        -- ^ 2 connection kill packet (lossy packet)
+    | UnspecifiedPacket -- ^ 3+ unspecified
+    | MessengerLossless -- ^ 16+  reserved for Messenger usage (lossless packets)
+    | MessengerLossy    -- ^ 192+ reserved for Messenger usage (lossy packets)
+    | Messenger255      -- ^ 255 reserved for Messenger usage (lossless packet)
+
+
+
+-- --> CookieRequest WithoutCookie
+-- <-- CookieResponse CookieAddress
+-- --> Handshake CookieAddress
+-- <-- Handshake CookieAddress
+
+-- Handshake packet:
+--    [uint8_t 26] (0x1a)
+--    [Cookie]
+--    [nonce (24 bytes)]
+--    [Encrypted message containing:
+--        [24 bytes base nonce]
+--        [session public key of the peer (32 bytes)]
+--        [sha512 hash of the entire Cookie sitting outside the encrypted part]
+--        [Other Cookie (used by the other to respond to the handshake packet)]
+--    ]
+
+-- cookie response packet (161 bytes):
+--
+--     [uint8_t 25]
+--     [Random nonce (24 bytes)]
+--     [Encrypted message containing:
+--         [Cookie]
+--         [uint64_t echo id (that was sent in the request)]
+--     ]
+--
+--     Encrypted message is encrypted with the exact same symmetric key as the
+--     cookie request packet it responds to but with a different nonce.
+--     (Encrypted message is encrypted with reqesters's DHT private key,
+--     responders's DHT public key and the nonce.)
+--
+--     Since we don't receive the public key, we will need to lookup the key by
+--     the SockAddr... I don't understand why the CookieResponse message is
+--     special this way.  TODO: implement a multimap (SockAddr -> SharedSecret)
+--     and wrap cookie queries with store/delete.  TODO: Should the entire
+--     SharedScret cache be keyed on only SockAddr ?  Perhaps the secret cache
+--     should be (NodeId -> Secret) and the cookie-request map should be
+--     (SockAddr -> NodeId)
+
+-- Encrypted packets:
+--
+--  Length    Contents
+-- :---------:--------------------------------------------------------------
+--  `1`       `uint8_t` (0x1b)
+--  `2`       `uint16_t` The last 2 bytes of the nonce used to encrypt this
+--  variable   Payload
+--
+-- The payload is encrypted with the session key and 'base nonce' set by the
+-- receiver in their handshake + packet number (starting at 0, big endian math).
+
+