1/*
2 *  OpenVPN -- An application to securely tunnel IP networks
3 *             over a single UDP port, with support for SSL/TLS-based
4 *             session authentication and key exchange,
5 *             packet encryption, packet authentication, and
6 *             packet compression.
7 *
8 *  Copyright (C) 2002-2010 OpenVPN Technologies, Inc. <sales@openvpn.net>
9 *
10 *  This program is free software; you can redistribute it and/or modify
11 *  it under the terms of the GNU General Public License version 2
12 *  as published by the Free Software Foundation.
13 *
14 *  This program is distributed in the hope that it will be useful,
15 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
16 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17 *  GNU General Public License for more details.
18 *
19 *  You should have received a copy of the GNU General Public License
20 *  along with this program (see the file COPYING included with this
21 *  distribution); if not, write to the Free Software Foundation, Inc.,
22 *  59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
23 */
24
25/*
26 * Each session is identified by a random 8-byte session identifier.
27 *
28 * For efficiency, the session id is only transmitted over the control
29 * channel (which only sees traffic occasionally when keys are being
30 * negotiated).
31 */
32
33#if defined(ENABLE_CRYPTO) && defined(ENABLE_SSL)
34
35#ifndef SESSION_ID_H
36#define SESSION_ID_H
37
38#include "basic.h"
39#include "buffer.h"
40
41struct session_id
42{
43  uint8_t id[8];
44};
45
46extern const struct session_id x_session_id_zero;
47
48#define SID_SIZE (sizeof (x_session_id_zero.id))
49
50static inline bool
51session_id_equal (const struct session_id *sid1,
52		  const struct session_id *sid2)
53{
54  return !memcmp (sid1->id, sid2->id, SID_SIZE);
55}
56
57static inline bool
58session_id_defined (const struct session_id *sid1)
59{
60  return memcmp (sid1->id, &x_session_id_zero.id, SID_SIZE) != 0;
61}
62
63static inline bool
64session_id_read (struct session_id *sid, struct buffer *buf)
65{
66  return buf_read (buf, sid->id, SID_SIZE);
67}
68
69static inline bool
70session_id_write_prepend (const struct session_id *sid, struct buffer *buf)
71{
72  return buf_write_prepend (buf, sid->id, SID_SIZE);
73}
74
75static inline bool
76session_id_write (const struct session_id *sid, struct buffer *buf)
77{
78  return buf_write (buf, sid->id, SID_SIZE);
79}
80
81void session_id_random (struct session_id *sid);
82
83const char *session_id_print (const struct session_id *sid, struct gc_arena *gc);
84
85#endif /* SESSION_ID_H */
86#endif /* ENABLE_CRYPTO && ENABLE_SSL */
87