session_id.h

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/*
 *  OpenVPN -- An application to securely tunnel IP networks
 *             over a single UDP port, with support for SSL/TLS-based
 *             session authentication and key exchange,
 *             packet encryption, packet authentication, and
 *             packet compression.
 *
 *  Copyright (C) 2002-2025 OpenVPN 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, see <https://www.gnu.org/licenses/>.
 */
 
/*
 * Each session is identified by a random 8-byte session identifier.
 *
 * For efficiency, the session id is only transmitted over the control
 * channel (which only sees traffic occasionally when keys are being
 * negotiated).
 */
 
#ifndef SESSION_ID_H
#define SESSION_ID_H
 
#include "basic.h"
#include "buffer.h"
 
struct session_id
{
    uint8_t id[8];
};
 
extern const struct session_id x_session_id_zero;
 
#define SID_SIZE (sizeof(x_session_id_zero.id))
 
static inline bool
session_id_equal(const struct session_id *sid1, const struct session_id *sid2)
{
    return !memcmp(sid1->id, sid2->id, SID_SIZE);
}
 
static inline bool
session_id_defined(const struct session_id *sid1)
{
    return memcmp(sid1->id, &x_session_id_zero.id, SID_SIZE) != 0;
}
 
static inline bool
session_id_read(struct session_id *sid, struct buffer *buf)
{
    return buf_read(buf, sid->id, SID_SIZE);
}
 
static inline bool
session_id_write_prepend(const struct session_id *sid, struct buffer *buf)
{
    return buf_write_prepend(buf, sid->id, SID_SIZE);
}
 
static inline bool
session_id_write(const struct session_id *sid, struct buffer *buf)
{
    return buf_write(buf, sid->id, SID_SIZE);
}
 
void session_id_random(struct session_id *sid);
 
const char *session_id_print(const struct session_id *sid, struct gc_arena *gc);
 
#endif /* SESSION_ID_H */