1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
|
{-# LANGUAGE KindSignatures #-}
module Network.Tox.Crypto.Transport
( parseNetCrypto
, encodeNetCrypto
-- CryptoTransport
, NetCrypto(..)
, CryptoData(..)
, CryptoMessage(..)
, CryptoPacket(..)
, HandshakeData(..)
, Handshake(..)
) where
import Crypto.Tox
import Network.Tox.DHT.Transport (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 _ _ = Left "TODO: parseNetCrypto"
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
-- cookie request packet (145 bytes)
--
-- [uint8_t 24]
-- [Sender's DHT Public key (32 bytes)]
-- [Random nonce (24 bytes)]
-- [Encrypted message containing:
-- [Sender's real public key (32 bytes)]
-- [padding (32 bytes)]
-- [uint64_t echo id (must be sent back untouched in cookie response)]
-- ]
-- 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).
|
