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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) 2002-2010 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 (see the file COPYING included with this
* distribution); if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/*
* This routines implement a reliability layer on top of UDP,
* so that TLS can be run over UDP.
*/
#if defined(USE_CRYPTO) && defined(USE_SSL)
#ifndef RELIABLE_H
#define RELIABLE_H
#include "basic.h"
#include "buffer.h"
#include "packet_id.h"
#include "session_id.h"
#include "mtu.h"
#define EXPONENTIAL_BACKOFF
#define RELIABLE_ACK_SIZE 8
struct reliable_ack
{
int len;
packet_id_type packet_id[RELIABLE_ACK_SIZE];
};
/* no active buffers? */
static inline bool
reliable_ack_empty (struct reliable_ack *ack)
{
return !ack->len;
}
/* get a packet_id from buf */
bool reliable_ack_read_packet_id (struct buffer *buf, packet_id_type *pid);
/* acknowledge a packet_id by adding it to a struct reliable_ack */
bool reliable_ack_acknowledge_packet_id (struct reliable_ack *ack, packet_id_type pid);
/* read a packet ID acknowledgement record from buf */
bool reliable_ack_read (struct reliable_ack *ack,
struct buffer *buf, const struct session_id *sid);
/* write a packet ID acknowledgement record to buf */
bool reliable_ack_write (struct reliable_ack *ack,
struct buffer *buf,
const struct session_id *sid, int max, bool prepend);
/* print a reliable ACK record coming off the wire */
const char *reliable_ack_print (struct buffer *buf, bool verbose, struct gc_arena *gc);
/* add to extra_frame the maximum number of bytes we will need for reliable_ack_write */
void reliable_ack_adjust_frame_parameters (struct frame* frame, int max);
void reliable_ack_debug_print (const struct reliable_ack *ack, char *desc);
#define RELIABLE_CAPACITY 8
struct reliable_entry
{
bool active;
interval_t timeout;
time_t next_try;
packet_id_type packet_id;
int opcode;
struct buffer buf;
};
struct reliable
{
int size;
interval_t initial_timeout;
packet_id_type packet_id;
int offset;
bool hold; /* don't xmit until reliable_schedule_now is called */
struct reliable_entry array[RELIABLE_CAPACITY];
};
void reliable_debug_print (const struct reliable *rel, char *desc);
/* set sending timeout (after this time we send again until ACK) */
static inline void
reliable_set_timeout (struct reliable *rel, interval_t timeout)
{
rel->initial_timeout = timeout;
}
void reliable_init (struct reliable *rel, int buf_size, int offset, int array_size, bool hold);
void reliable_free (struct reliable *rel);
/* no active buffers? */
bool reliable_empty (const struct reliable *rel);
/* in how many seconds should we wake up to check for timeout */
interval_t reliable_send_timeout (const struct reliable *rel);
/* del acknowledged items from send buf */
void reliable_send_purge (struct reliable *rel, struct reliable_ack *ack);
/* true if at least one free buffer available */
bool reliable_can_get (const struct reliable *rel);
/* make sure that incoming packet ID isn't a replay */
bool reliable_not_replay (const struct reliable *rel, packet_id_type id);
/* make sure that incoming packet ID won't deadlock the receive buffer */
bool reliable_wont_break_sequentiality (const struct reliable *rel, packet_id_type id);
/* grab a free buffer */
struct buffer *reliable_get_buf (struct reliable *rel);
/* grab a free buffer, fail if buffer clogged by unacknowledged low packet IDs */
struct buffer *reliable_get_buf_output_sequenced (struct reliable *rel);
/* get active buffer for next sequentially increasing key ID */
struct buffer *reliable_get_buf_sequenced (struct reliable *rel);
/* return true if reliable_send would return a non-NULL result */
bool reliable_can_send (const struct reliable *rel);
/* return next buffer to send to remote */
struct buffer *reliable_send (struct reliable *rel, int *opcode);
/* schedule all pending packets for immediate retransmit */
void reliable_schedule_now (struct reliable *rel);
/* enable an incoming buffer previously returned by a get function as active */
void reliable_mark_active_incoming (struct reliable *rel, struct buffer *buf,
packet_id_type pid, int opcode);
/* enable an outgoing buffer previously returned by a get function as active. */
void reliable_mark_active_outgoing (struct reliable *rel, struct buffer *buf, int opcode);
/* delete a buffer previously activated by reliable_mark_active() */
void reliable_mark_deleted (struct reliable *rel, struct buffer *buf, bool inc_pid);
#endif /* RELIABLE_H */
#endif /* USE_CRYPTO && USE_SSL */
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