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
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
|
/* $Id$ */
/*
* This file is part of OpenTTD.
* OpenTTD 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, version 2.
* OpenTTD 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 OpenTTD. If not, see <http://www.gnu.org/licenses/>.
*/
/**
* @file packet.cpp Basic functions to create, fill and read packets.
*/
#ifdef ENABLE_NETWORK
#include "../../stdafx.h"
#include "../../string_func.h"
#include "packet.h"
/**
* Create a packet that is used to read from a network socket
* @param cs the socket handler associated with the socket we are reading from
*/
Packet::Packet(NetworkSocketHandler *cs)
{
assert(cs != NULL);
this->cs = cs;
this->next = NULL;
this->pos = 0; // We start reading from here
this->size = 0;
}
/**
* Creates a packet to send
* @param type of the packet to send
*/
Packet::Packet(PacketType type)
{
this->cs = NULL;
this->next = NULL;
/* Skip the size so we can write that in before sending the packet */
this->pos = 0;
this->size = sizeof(PacketSize);
this->buffer[this->size++] = type;
}
/**
* Create a packet for sending
* @param type the of packet
* @return the newly created packet
*/
Packet *NetworkSend_Init(PacketType type)
{
Packet *packet = new Packet(type);
/* An error is inplace here, because it simply means we ran out of memory. */
if (packet == NULL) error("Failed to allocate Packet");
return packet;
}
/**
* Writes the packet size from the raw packet from packet->size
*/
void Packet::PrepareToSend()
{
assert(this->cs == NULL && this->next == NULL);
this->buffer[0] = GB(this->size, 0, 8);
this->buffer[1] = GB(this->size, 8, 8);
this->pos = 0; // We start reading from here
}
/**
* The next couple of functions make sure we can send
* uint8, uint16, uint32 and uint64 endian-safe
* over the network. The least significant bytes are
* sent first.
*
* So 0x01234567 would be sent as 67 45 23 01.
*
* A bool is sent as a uint8 where zero means false
* and non-zero means true.
*/
void Packet::Send_bool(bool data)
{
this->Send_uint8(data ? 1 : 0);
}
void Packet::Send_uint8(uint8 data)
{
assert(this->size < sizeof(this->buffer) - sizeof(data));
this->buffer[this->size++] = data;
}
void Packet::Send_uint16(uint16 data)
{
assert(this->size < sizeof(this->buffer) - sizeof(data));
this->buffer[this->size++] = GB(data, 0, 8);
this->buffer[this->size++] = GB(data, 8, 8);
}
void Packet::Send_uint32(uint32 data)
{
assert(this->size < sizeof(this->buffer) - sizeof(data));
this->buffer[this->size++] = GB(data, 0, 8);
this->buffer[this->size++] = GB(data, 8, 8);
this->buffer[this->size++] = GB(data, 16, 8);
this->buffer[this->size++] = GB(data, 24, 8);
}
void Packet::Send_uint64(uint64 data)
{
assert(this->size < sizeof(this->buffer) - sizeof(data));
this->buffer[this->size++] = GB(data, 0, 8);
this->buffer[this->size++] = GB(data, 8, 8);
this->buffer[this->size++] = GB(data, 16, 8);
this->buffer[this->size++] = GB(data, 24, 8);
this->buffer[this->size++] = GB(data, 32, 8);
this->buffer[this->size++] = GB(data, 40, 8);
this->buffer[this->size++] = GB(data, 48, 8);
this->buffer[this->size++] = GB(data, 56, 8);
}
/**
* Sends a string over the network. It sends out
* the string + '\0'. No size-byte or something.
* @param data the string to send
*/
void Packet::Send_string(const char *data)
{
assert(data != NULL);
/* The <= *is* valid due to the fact that we are comparing sizes and not the index. */
assert(this->size + strlen(data) + 1 <= sizeof(this->buffer));
while ((this->buffer[this->size++] = *data++) != '\0') {}
}
/**
* Receiving commands
* Again, the next couple of functions are endian-safe
* see the comment before Send_bool for more info.
*/
/** Is it safe to read from the packet, i.e. didn't we run over the buffer ? */
bool Packet::CanReadFromPacket(uint bytes_to_read)
{
/* Don't allow reading from a quit client/client who send bad data */
if (this->cs->HasClientQuit()) return false;
/* Check if variable is within packet-size */
if (this->pos + bytes_to_read > this->size) {
this->cs->CloseConnection();
return false;
}
return true;
}
/**
* Reads the packet size from the raw packet and stores it in the packet->size
*/
void Packet::ReadRawPacketSize()
{
assert(this->cs != NULL && this->next == NULL);
this->size = (PacketSize)this->buffer[0];
this->size += (PacketSize)this->buffer[1] << 8;
}
/**
* Prepares the packet so it can be read
*/
void Packet::PrepareToRead()
{
this->ReadRawPacketSize();
/* Put the position on the right place */
this->pos = sizeof(PacketSize);
}
bool Packet::Recv_bool()
{
return this->Recv_uint8() != 0;
}
uint8 Packet::Recv_uint8()
{
uint8 n;
if (!this->CanReadFromPacket(sizeof(n))) return 0;
n = this->buffer[this->pos++];
return n;
}
uint16 Packet::Recv_uint16()
{
uint16 n;
if (!this->CanReadFromPacket(sizeof(n))) return 0;
n = (uint16)this->buffer[this->pos++];
n += (uint16)this->buffer[this->pos++] << 8;
return n;
}
uint32 Packet::Recv_uint32()
{
uint32 n;
if (!this->CanReadFromPacket(sizeof(n))) return 0;
n = (uint32)this->buffer[this->pos++];
n += (uint32)this->buffer[this->pos++] << 8;
n += (uint32)this->buffer[this->pos++] << 16;
n += (uint32)this->buffer[this->pos++] << 24;
return n;
}
uint64 Packet::Recv_uint64()
{
uint64 n;
if (!this->CanReadFromPacket(sizeof(n))) return 0;
n = (uint64)this->buffer[this->pos++];
n += (uint64)this->buffer[this->pos++] << 8;
n += (uint64)this->buffer[this->pos++] << 16;
n += (uint64)this->buffer[this->pos++] << 24;
n += (uint64)this->buffer[this->pos++] << 32;
n += (uint64)this->buffer[this->pos++] << 40;
n += (uint64)this->buffer[this->pos++] << 48;
n += (uint64)this->buffer[this->pos++] << 56;
return n;
}
/** Reads a string till it finds a '\0' in the stream */
void Packet::Recv_string(char *buffer, size_t size, bool allow_newlines)
{
PacketSize pos;
char *bufp = buffer;
const char *last = buffer + size - 1;
/* Don't allow reading from a closed socket */
if (cs->HasClientQuit()) return;
pos = this->pos;
while (--size > 0 && pos < this->size && (*buffer++ = this->buffer[pos++]) != '\0') {}
if (size == 0 || pos == this->size) {
*buffer = '\0';
/* If size was sooner to zero then the string in the stream
* skip till the \0, so than packet can be read out correctly for the rest */
while (pos < this->size && this->buffer[pos] != '\0') pos++;
pos++;
}
this->pos = pos;
str_validate(bufp, last, allow_newlines);
}
#endif /* ENABLE_NETWORK */
|
