ccid2.h

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/*
 *  Copyright (c) 2005 Andrea Bittau <[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_CCID2_H_
#define _DCCP_CCID2_H_

#include <linux/timer.h>
#include <linux/types.h>
#include "../ccid.h"
#include "../dccp.h"

/*
 * CCID-2 timestamping faces the same issues as TCP timestamping.
 * Hence we reuse/share as much of the code as possible.
 */
#define ccid2_time_stamp    tcp_time_stamp

/* NUMDUPACK parameter from RFC 4341, p. 6 */
#define NUMDUPACK   3

struct ccid2_seq {
    u64         ccid2s_seq;
    u32         ccid2s_sent;
    int         ccid2s_acked;
    struct ccid2_seq    *ccid2s_prev;
    struct ccid2_seq    *ccid2s_next;
};

#define CCID2_SEQBUF_LEN 1024
#define CCID2_SEQBUF_MAX 128

/*
 * Multiple of congestion window to keep the sequence window at
 * (RFC 4340 7.5.2)
 */
#define CCID2_WIN_CHANGE_FACTOR 5

struct ccid2_hc_tx_sock {
    u32         tx_cwnd;
    u32         tx_ssthresh;
    u32         tx_pipe;
    u32         tx_packets_acked;
    struct ccid2_seq    *tx_seqbuf[CCID2_SEQBUF_MAX];
    int         tx_seqbufc;
    struct ccid2_seq    *tx_seqh;
    struct ccid2_seq    *tx_seqt;

    /* RTT measurement: variables/principles are the same as in TCP */
    u32         tx_srtt,
                tx_mdev,
                tx_mdev_max,
                tx_rttvar,
                tx_rto;
    u64         tx_rtt_seq:48;
    struct timer_list   tx_rtotimer;

    /* Congestion Window validation (optional, RFC 2861) */
    u32         tx_cwnd_used,
                tx_expected_wnd,
                tx_cwnd_stamp,
                tx_lsndtime;

    u64         tx_rpseq;
    int         tx_rpdupack;
    u32         tx_last_cong;
    u64         tx_high_ack;
    struct list_head    tx_av_chunks;
};

static inline bool ccid2_cwnd_network_limited(struct ccid2_hc_tx_sock *hc)
{
    return hc->tx_pipe >= hc->tx_cwnd;
}

/*
 * Convert RFC 3390 larger initial window into an equivalent number of packets.
 * This is based on the numbers specified in RFC 5681, 3.1.
 */
static inline u32 rfc3390_bytes_to_packets(const u32 smss)
{
    return smss <= 1095 ? 4 : (smss > 2190 ? 2 : 3);
}

struct ccid2_hc_rx_sock {
    u32 rx_num_data_pkts;
};

static inline struct ccid2_hc_tx_sock *ccid2_hc_tx_sk(const struct sock *sk)
{
    return ccid_priv(dccp_sk(sk)->dccps_hc_tx_ccid);
}

static inline struct ccid2_hc_rx_sock *ccid2_hc_rx_sk(const struct sock *sk)
{
    return ccid_priv(dccp_sk(sk)->dccps_hc_rx_ccid);
}
#endif /* _DCCP_CCID2_H_ */