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
|
/*
* OpenVPN -- An application to securely tunnel IP networks
* over a single TCP/UDP port, with support for SSL/TLS-based
* session authentication and key exchange,
* packet encryption, packet authentication, and
* packet compression.
*
* Copyright (C) 2002-2017 OpenVPN Technologies, Inc. <sales@openvpn.net>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation.
*
* 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.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#elif defined(_MSC_VER)
#include "config-msvc.h"
#endif
#include "syshead.h"
#include "proto.h"
#include "error.h"
#include "memdbg.h"
/*
* If raw tunnel packet is IPv<X>, return true and increment
* buffer offset to start of IP header.
*/
static
bool
is_ipv_X( int tunnel_type, struct buffer *buf, int ip_ver )
{
int offset;
const struct openvpn_iphdr *ih;
verify_align_4(buf);
if (tunnel_type == DEV_TYPE_TUN)
{
if (BLEN(buf) < (int) sizeof(struct openvpn_iphdr))
{
return false;
}
offset = 0;
}
else if (tunnel_type == DEV_TYPE_TAP)
{
const struct openvpn_ethhdr *eh;
if (BLEN(buf) < (int)(sizeof(struct openvpn_ethhdr)
+ sizeof(struct openvpn_iphdr)))
{
return false;
}
eh = (const struct openvpn_ethhdr *) BPTR(buf);
if (ntohs(eh->proto) != (ip_ver == 6 ? OPENVPN_ETH_P_IPV6 : OPENVPN_ETH_P_IPV4))
{
return false;
}
offset = sizeof(struct openvpn_ethhdr);
}
else
{
return false;
}
ih = (const struct openvpn_iphdr *) (BPTR(buf) + offset);
/* IP version is stored in the same bits for IPv4 or IPv6 header */
if (OPENVPN_IPH_GET_VER(ih->version_len) == ip_ver)
{
return buf_advance(buf, offset);
}
else
{
return false;
}
}
bool
is_ipv4(int tunnel_type, struct buffer *buf)
{
return is_ipv_X( tunnel_type, buf, 4 );
}
bool
is_ipv6(int tunnel_type, struct buffer *buf)
{
return is_ipv_X( tunnel_type, buf, 6 );
}
#ifdef PACKET_TRUNCATION_CHECK
void
ipv4_packet_size_verify(const uint8_t *data,
const int size,
const int tunnel_type,
const char *prefix,
counter_type *errors)
{
if (size > 0)
{
struct buffer buf;
buf_set_read(&buf, data, size);
if (is_ipv4(tunnel_type, &buf))
{
const struct openvpn_iphdr *pip;
int hlen;
int totlen;
const char *msgstr = "PACKET SIZE INFO";
unsigned int msglevel = D_PACKET_TRUNC_DEBUG;
if (BLEN(&buf) < (int) sizeof(struct openvpn_iphdr))
{
return;
}
verify_align_4(&buf);
pip = (struct openvpn_iphdr *) BPTR(&buf);
hlen = OPENVPN_IPH_GET_LEN(pip->version_len);
totlen = ntohs(pip->tot_len);
if (BLEN(&buf) != totlen)
{
msgstr = "PACKET TRUNCATION ERROR";
msglevel = D_PACKET_TRUNC_ERR;
if (errors)
{
++(*errors);
}
}
msg(msglevel, "%s %s: size=%d totlen=%d hlen=%d errcount=" counter_format,
msgstr,
prefix,
BLEN(&buf),
totlen,
hlen,
errors ? *errors : (counter_type)0);
}
}
}
#endif /* ifdef PACKET_TRUNCATION_CHECK */
|
