ccid3.h

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/*
 *  Copyright (c) 2005-7 The University of Waikato, Hamilton, New Zealand.
 *  Copyright (c) 2007   The University of Aberdeen, Scotland, UK
 *
 *  An implementation of the DCCP protocol
 *
 *  This code has been developed by the University of Waikato WAND
 *  research group. For further information please see http://www.wand.net.nz/
 *  or e-mail Ian McDonald - [email protected]
 *
 *  This code also uses code from Lulea University, rereleased as GPL by its
 *  authors:
 *  Copyright (c) 2003 Nils-Erik Mattsson, Joacim Haggmark, Magnus Erixzon
 *
 *  Changes to meet Linux coding standards, to make it meet latest ccid3 draft
 *  and to make it work as a loadable module in the DCCP stack written by
 *  Arnaldo Carvalho de Melo <[email protected]>.
 *
 *  Copyright (c) 2005 Arnaldo Carvalho de Melo <[email protected]>
 *
 *  This program 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.
 *
 *  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., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
#ifndef _DCCP_CCID3_H_
#define _DCCP_CCID3_H_

#include <linux/ktime.h>
#include <linux/list.h>
#include <linux/types.h>
#include <linux/tfrc.h>
#include "lib/tfrc.h"
#include "../ccid.h"

/* Two seconds as per RFC 5348, 4.2 */
#define TFRC_INITIAL_TIMEOUT       (2 * USEC_PER_SEC)

/* Parameter t_mbi from [RFC 3448, 4.3]: backoff interval in seconds */
#define TFRC_T_MBI         64

/*
 * The t_delta parameter (RFC 5348, 8.3): delays of less than %USEC_PER_MSEC are
 * rounded down to 0, since sk_reset_timer() here uses millisecond granularity.
 * Hence we can use a constant t_delta = %USEC_PER_MSEC when HZ >= 500. A coarse
 * resolution of HZ < 500 means that the error is below one timer tick (t_gran)
 * when using the constant t_delta  =  t_gran / 2  =  %USEC_PER_SEC / (2 * HZ).
 */
#if (HZ >= 500)
# define TFRC_T_DELTA          USEC_PER_MSEC
#else
# define TFRC_T_DELTA          (USEC_PER_SEC / (2 * HZ))
#endif

enum ccid3_options {
    TFRC_OPT_LOSS_EVENT_RATE = 192,
    TFRC_OPT_LOSS_INTERVALS  = 193,
    TFRC_OPT_RECEIVE_RATE    = 194,
};

/* TFRC sender states */
enum ccid3_hc_tx_states {
    TFRC_SSTATE_NO_SENT = 1,
    TFRC_SSTATE_NO_FBACK,
    TFRC_SSTATE_FBACK,
};

struct ccid3_hc_tx_sock {
    u64             tx_x;
    u64             tx_x_recv;
    u32             tx_x_calc;
    u32             tx_rtt;
    u32             tx_p;
    u32             tx_t_rto;
    u32             tx_t_ipi;
    u16             tx_s;
    enum ccid3_hc_tx_states     tx_state:8;
    u8              tx_last_win_count;
    ktime_t             tx_t_last_win_count;
    struct timer_list       tx_no_feedback_timer;
    ktime_t             tx_t_ld;
    ktime_t             tx_t_nom;
    struct tfrc_tx_hist_entry   *tx_hist;
};

static inline struct ccid3_hc_tx_sock *ccid3_hc_tx_sk(const struct sock *sk)
{
    struct ccid3_hc_tx_sock *hctx = ccid_priv(dccp_sk(sk)->dccps_hc_tx_ccid);
    BUG_ON(hctx == NULL);
    return hctx;
}

/* TFRC receiver states */
enum ccid3_hc_rx_states {
    TFRC_RSTATE_NO_DATA = 1,
    TFRC_RSTATE_DATA,
};

struct ccid3_hc_rx_sock {
    u8              rx_last_counter:4;
    enum ccid3_hc_rx_states     rx_state:8;
    u32             rx_bytes_recv;
    u32             rx_x_recv;
    u32             rx_rtt;
    ktime_t             rx_tstamp_last_feedback;
    struct tfrc_rx_hist     rx_hist;
    struct tfrc_loss_hist       rx_li_hist;
    u16             rx_s;
#define rx_pinv             rx_li_hist.i_mean
};

static inline struct ccid3_hc_rx_sock *ccid3_hc_rx_sk(const struct sock *sk)
{
    struct ccid3_hc_rx_sock *hcrx = ccid_priv(dccp_sk(sk)->dccps_hc_rx_ccid);
    BUG_ON(hcrx == NULL);
    return hcrx;
}

#endif /* _DCCP_CCID3_H_ */