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
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
|
/* <!-- copyright */
/*
* aria2 - a simple utility for downloading files faster
*
* Copyright (C) 2006 Tatsuhiro Tsujikawa
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/* copyright --> */
#include "PeerMessageUtil.h"
#include "DlAbortEx.h"
#include "Util.h"
#include <netinet/in.h>
PeerMessage* PeerMessageUtil::createPeerMessage(const char* msg, int len) {
PeerMessage* peerMessage;
if(len == 0) {
// keep-alive
peerMessage = new PeerMessage();
peerMessage->setId(PeerMessage::KEEP_ALIVE);
return peerMessage;
}
int id = getId(msg);
switch(id) {
case PeerMessage::CHOKE:
case PeerMessage::UNCHOKE:
case PeerMessage::INTERESTED:
case PeerMessage::NOT_INTERESTED:
peerMessage = createBasicMessage(id, msg, len);
break;
case PeerMessage::HAVE:
peerMessage = createHaveMessage(id, msg, len);
break;
case PeerMessage::BITFIELD:
peerMessage = createBitfieldMessage(id, msg, len);
break;
case PeerMessage::REQUEST:
case PeerMessage::CANCEL:
peerMessage = createRequestCancelMessage(id, msg, len);
break;
case PeerMessage::PIECE:
peerMessage = createPieceMessage(id, msg, len);
break;
default:
throw new DlAbortEx("invalid message id. id = %d", id);
}
return peerMessage;
}
PeerMessage* PeerMessageUtil::createBasicMessage(int id, const char* msg, int len) {
if(len != 1) {
throw new DlAbortEx("invalid payload size for ID%d, size = %d. It should be %d", id, len, 1);
}
PeerMessage* peerMessage = new PeerMessage();
peerMessage->setId(id);
return peerMessage;
}
PeerMessage* PeerMessageUtil::createHaveMessage(int id, const char* msg, int len) {
if(len != 5) {
throw new DlAbortEx("invalid payload size for ID%d, size = %d. It should be %d", id, len, 5);
}
PeerMessage* peerMessage = new PeerMessage();
peerMessage->setId(id);
peerMessage->setIndex(getIntParam(msg, 1));
return peerMessage;
}
PeerMessage* PeerMessageUtil::createBitfieldMessage(int id, const char* msg, int len) {
if(len <= 1) {
throw new DlAbortEx("invalid payload size for ID%d, size = %d. It should be greater than %d", id, len, 1);
}
PeerMessage* peerMessage = new PeerMessage();
peerMessage->setId(id);
peerMessage->setBitfield((unsigned char*)msg+1, len-1);
return peerMessage;
}
PeerMessage* PeerMessageUtil::createRequestCancelMessage(int id, const char* msg, int len) {
if(len != 13) {
throw new DlAbortEx("invalid payload size for ID%d, size = %d. It should be %d", id, len, 13);
}
PeerMessage* peerMessage = new PeerMessage();
peerMessage->setId(id);
peerMessage->setIndex(getIntParam(msg, 1));
peerMessage->setBegin(getIntParam(msg, 5));
peerMessage->setLength(getIntParam(msg, 9));
return peerMessage;
}
PeerMessage* PeerMessageUtil::createPieceMessage(int id, const char* msg, int len) {
if(len <= 9) {
throw new DlAbortEx("invalid payload size for ID%d, size = %d. It should be greater than %d", id, len, 9);
}
PeerMessage* peerMessage = new PeerMessage();
peerMessage->setId(id);
peerMessage->setIndex(getIntParam(msg, 1));
peerMessage->setBegin(getIntParam(msg, 5));
peerMessage->setBlock(msg+9, len-9);
return peerMessage;
}
int PeerMessageUtil::getId(const char* msg) {
return (int)msg[0];
}
int PeerMessageUtil::getIntParam(const char* msg, int offset) {
int nParam;
memcpy(&nParam, msg+offset, 4);
return ntohl(nParam);
}
void PeerMessageUtil::checkIndex(const PeerMessage* message, int pieces) {
if(!(0 <= message->getIndex() && message->getIndex() < pieces)) {
throw new DlAbortEx("invalid index = %d", message->getIndex());
}
}
void PeerMessageUtil::checkBegin(const PeerMessage* message, int pieceLength) {
if(!(0 <= message->getBegin() && message->getBegin() < pieceLength)) {
throw new DlAbortEx("invalid begin = %d", message->getBegin());
}
}
void PeerMessageUtil::checkPieceOffset(const PeerMessage* message, int pieceLength, int pieces, long long int totalLength) {
if(!(0 <= message->getBegin() && 0 < message->getLength())) {
throw new DlAbortEx("invalid offset, begin = %d, length = %d", message->getBegin(), message->getLength());
}
int offset = message->getBegin()+message->getLength();
int currentPieceLength;
if(message->getIndex()+1 == pieces) {
currentPieceLength = pieceLength-(pieces*pieceLength-totalLength);
} else {
currentPieceLength = pieceLength;
}
if(!(0 < offset && offset <= currentPieceLength)) {
throw new DlAbortEx("invalid offset, begin = %d, length = %d", message->getBegin(), message->getLength());
}
}
void PeerMessageUtil::checkLength(const PeerMessage* message) {
if(message->getLength() > MAX_BLOCK_LENGTH) {
throw new DlAbortEx("too large length %d > %dKB", message->getLength(),
MAX_BLOCK_LENGTH/1024);
}
if(!Util::isPowerOf(message->getLength(), 2)) {
throw new DlAbortEx("invalid length %d, which is not power of 2",
message->getLength());
}
}
void PeerMessageUtil::checkBitfield(const PeerMessage* message, int pieces) {
if(!(message->getBitfieldLength() == BITFIELD_LEN_FROM_PIECES(pieces))) {
throw new DlAbortEx("invalid bitfield length = %d", message->getBitfieldLength());
}
char lastbyte = message->getBitfield()[message->getBitfieldLength()-1];
for(int i = 0; i < 8-pieces%8 && pieces%8 != 0; i++) {
if(!(((lastbyte >> i) & 1) == 0)) {
throw new DlAbortEx("invalid bitfield");
}
}
}
void PeerMessageUtil::checkIntegrity(const PeerMessage* message, int pieceLength, int pieces, long long int totalLength) {
// 0 <= index < pieces
// 0 <= begin < pieceLength
// 0 < begin+length <= pieceLength
// len of bitfield == pieces/8+(pieces%8 ? 1 : 0)
// for(int i = 0; i < 8-pieces%8; i++) { ((lastbyteofbitfield >> i) & 1) == 0 }
switch(message->getId()) {
case PeerMessage::KEEP_ALIVE:
case PeerMessage::CHOKE:
case PeerMessage::UNCHOKE:
case PeerMessage::INTERESTED:
case PeerMessage::NOT_INTERESTED:
break;
case PeerMessage::HAVE:
checkIndex(message, pieces);
break;
case PeerMessage::BITFIELD:
checkBitfield(message, pieces);
break;
case PeerMessage::REQUEST:
case PeerMessage::CANCEL:
checkIndex(message, pieces);
checkBegin(message, pieceLength);
checkLength(message);
checkPieceOffset(message, pieceLength, pieces, totalLength);
break;
case PeerMessage::PIECE:
checkIndex(message, pieces);
checkBegin(message, pieceLength);
break;
default:
throw new DlAbortEx("invalid message id. id = %d", message->getId());
}
}
HandshakeMessage* PeerMessageUtil::createHandshakeMessage(const char* msg) {
HandshakeMessage* message = new HandshakeMessage();
message->pstrlen = msg[0];
char pstr[20];
memcpy(pstr, &msg[1], sizeof(pstr)-1);
pstr[sizeof(pstr)-1] = '\0';
message->pstr = pstr;
memcpy(message->infoHash, &msg[28], 20);
memcpy(message->peerId, &msg[48], 20);
return message;
}
void PeerMessageUtil::checkHandshake(const HandshakeMessage* message, const unsigned char* infoHash) {
if(message->pstrlen != 19) {
throw new DlAbortEx("invalid handshake pstrlen = %d", (int)message->pstrlen);
}
if(message->pstr != PSTR) {
throw new DlAbortEx("invalid handshake pstr");
}
string myInfoHash = Util::toHex(infoHash, 20);
string peerInfoHash = Util::toHex(message->infoHash, 20);
if(myInfoHash != peerInfoHash) {
throw new DlAbortEx("invalid handshake info hash: expected:%s, actual:%s",
myInfoHash.c_str(), peerInfoHash.c_str());
}
}
|
