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
|
/*
===========================================================================
Copyright (C) 1999-2005 Id Software, Inc.
This file is part of Quake III Arena source code.
Quake III Arena source code 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.
Quake III Arena source code 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 Foobar; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
===========================================================================
*/
#include "../qcommon/q_shared.h"
#include "../qcommon/qcommon.h"
#include "client.h"
/*
==============
CL_Netchan_Encode
// first 12 bytes of the data are always:
long serverId;
long messageAcknowledge;
long reliableAcknowledge;
==============
*/
static void CL_Netchan_Encode( msg_t *msg ) {
int serverId, messageAcknowledge, reliableAcknowledge;
int i, index, srdc, sbit, soob;
byte key, *string;
if ( msg->cursize <= CL_ENCODE_START ) {
return;
}
srdc = msg->readcount;
sbit = msg->bit;
soob = msg->oob;
msg->bit = 0;
msg->readcount = 0;
msg->oob = 0;
serverId = MSG_ReadLong(msg);
messageAcknowledge = MSG_ReadLong(msg);
reliableAcknowledge = MSG_ReadLong(msg);
msg->oob = soob;
msg->bit = sbit;
msg->readcount = srdc;
string = (byte *)clc.serverCommands[ reliableAcknowledge & (MAX_RELIABLE_COMMANDS-1) ];
index = 0;
//
key = clc.challenge ^ serverId ^ messageAcknowledge;
for (i = CL_ENCODE_START; i < msg->cursize; i++) {
// modify the key with the last received now acknowledged server command
if (!string[index])
index = 0;
if (string[index] > 127 || string[index] == '%') {
key ^= '.' << (i & 1);
}
else {
key ^= string[index] << (i & 1);
}
index++;
// encode the data with this key
*(msg->data + i) = (*(msg->data + i)) ^ key;
}
}
/*
==============
CL_Netchan_Decode
// first four bytes of the data are always:
long reliableAcknowledge;
==============
*/
static void CL_Netchan_Decode( msg_t *msg ) {
long reliableAcknowledge, i, index;
byte key, *string;
int srdc, sbit, soob;
srdc = msg->readcount;
sbit = msg->bit;
soob = msg->oob;
msg->oob = 0;
reliableAcknowledge = MSG_ReadLong(msg);
msg->oob = soob;
msg->bit = sbit;
msg->readcount = srdc;
string = (byte *) clc.reliableCommands[ reliableAcknowledge & (MAX_RELIABLE_COMMANDS-1) ];
index = 0;
// xor the client challenge with the netchan sequence number (need something that changes every message)
key = clc.challenge ^ LittleLong( *(unsigned *)msg->data );
for (i = msg->readcount + CL_DECODE_START; i < msg->cursize; i++) {
// modify the key with the last sent and with this message acknowledged client command
if (!string[index])
index = 0;
if (string[index] > 127 || string[index] == '%') {
key ^= '.' << (i & 1);
}
else {
key ^= string[index] << (i & 1);
}
index++;
// decode the data with this key
*(msg->data + i) = *(msg->data + i) ^ key;
}
}
/*
=================
CL_Netchan_TransmitNextFragment
=================
*/
void CL_Netchan_TransmitNextFragment( netchan_t *chan ) {
Netchan_TransmitNextFragment( chan );
}
/*
===============
CL_Netchan_Transmit
================
*/
void CL_Netchan_Transmit( netchan_t *chan, msg_t* msg ) {
MSG_WriteByte( msg, clc_EOF );
CL_Netchan_Encode( msg );
Netchan_Transmit( chan, msg->cursize, msg->data );
}
extern int oldsize;
int newsize = 0;
/*
=================
CL_Netchan_Process
=================
*/
qboolean CL_Netchan_Process( netchan_t *chan, msg_t *msg ) {
int ret;
ret = Netchan_Process( chan, msg );
if (!ret)
return qfalse;
CL_Netchan_Decode( msg );
newsize += msg->cursize;
return qtrue;
}
|
