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
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
|
-- |
-- Copyright : (c) Sam T. 2013
-- License : MIT
-- Maintainer : pxqr.sta@gmail.com
-- Stability : experimental
-- Portability : portable
--
-- This module implement low-level UDP tracker protocol.
-- For more info see: http://www.bittorrent.org/beps/bep_0015.html
--
{-# LANGUAGE RecordWildCards #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE GeneralizedNewtypeDeriving #-}
module Network.BitTorrent.Tracker.UDP
( Request(..), Response(..)
) where
import Control.Applicative
import Control.Monad
import Data.Serialize
import Data.Word
import Data.Text
import Data.Text.Encoding
import Data.Torrent ()
import Network.BitTorrent.Tracker.Protocol
-- | Connection Id is used for entire tracker session.
newtype ConnId = ConnId { getConnId :: Word64 }
deriving (Show, Serialize)
-- | Transaction Id is used for within UDP RPC.
newtype TransId = TransId { getTransId :: Word32 }
deriving (Show, Serialize)
genConnectionId :: IO ConnId
genConnectionId = return (ConnId 0)
genTransactionId :: IO TransId
genTransactionId = return (TransId 0)
data Request = Connect
| Announce AnnounceQuery
| Scrape ScrapeQuery
data Response = Connected
| Announced AnnounceInfo
| Scraped [ScrapeInfo]
| Failed Text
-- TODO rename to message?
data Transaction a = Transaction
{ connId :: !ConnId
, transId :: !TransId
, body :: !a
} deriving Show
type MessageId = Word32
connectId, announceId, scrapeId, errorId :: MessageId
connectId = 0
announceId = 1
scrapeId = 2
errorId = 3
instance Serialize (Transaction Request) where
put Transaction {..} = do
case body of
Connect -> do
put connId
put connectId
put transId
Announce query -> do
put connId
put announceId
put transId
put query
Scrape hashes -> do
put connId
put announceId
put transId
forM_ hashes put
get = do
cid <- get
rid <- getWord32be
tid <- get
bod <- getBody rid
return $ Transaction {
connId = cid
, transId = tid
, body = bod
}
where
getBody :: MessageId -> Get Request
getBody msgId
| msgId == connectId = return Connect
| msgId == announceId = Announce <$> get
| msgId == scrapeId = Scrape <$> many get
| otherwise = fail "unknown message id"
instance Serialize (Transaction Response) where
put Transaction {..} = do
case body of
Connected -> do
put connId
put connectId
put transId
Announced info -> do
put connId
put announceId
put transId
put info
Scraped infos -> do
put connId
put scrapeId
put transId
forM_ infos put
Failed info -> do
put connId
put errorId
put transId
put (encodeUtf8 info)
get = do
cid <- get
rid <- getWord32be
tid <- get
bod <- getBody rid
return $ Transaction {
connId = cid
, transId = tid
, body = bod
}
where
getBody :: MessageId -> Get Response
getBody msgId
| msgId == connectId = return $ Connected
| msgId == announceId = Announced <$> get
| msgId == scrapeId = Scraped <$> many get
| msgId == errorId = do
bs <- get
case decodeUtf8' bs of
Left ex -> fail (show ex)
Right msg -> return $ Failed msg
| otherwise = fail "unknown message id"
|
