/*
 *  net/dccp/ccids/ccid2.h
 *
 *  Copyright (c) 2005 Andrea Bittau <a.bittau@cs.ucl.ac.uk>
 *
 *  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/dccp.h>
#include <linux/timer.h>
#include <linux/types.h>
#include "../ccid.h"
/* NUMDUPACK parameter from RFC 4341, p. 6 */
#define NUMDUPACK	3

struct sock;

struct ccid2_seq {
	u64			ccid2s_seq;
	unsigned long		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

/** struct ccid2_hc_tx_sock - CCID2 TX half connection
 *
 * @{cwnd,ssthresh,pipe}: as per RFC 4341, section 5
 * @packets_acked: Ack counter for deriving cwnd growth (RFC 3465)
 * @srtt: smoothed RTT estimate, scaled by 2^3
 * @mdev: smoothed RTT variation, scaled by 2^2
 * @mdev_max: maximum of @mdev during one flight
 * @rttvar: moving average/maximum of @mdev_max
 * @rto: RTO value deriving from SRTT and RTTVAR (RFC 2988)
 * @rtt_seq: to decay RTTVAR at most once per flight
 * @rpseq: last consecutive seqno
 * @rpdupack: dupacks since rpseq
 * @av_chunks: list of Ack Vectors received on current skb
 */
struct ccid2_hc_tx_sock {
	u32			cwnd;
	u32			ssthresh;
	u32			pipe;
	u32			packets_acked;
	struct ccid2_seq	*seqbuf[CCID2_SEQBUF_MAX];
	int			seqbufc;
	struct ccid2_seq	*seqh;
	struct ccid2_seq	*seqt;
	/* RTT measurement: variables/principles are the same as in TCP */
	u32			srtt,
				mdev,
				mdev_max,
				rttvar,
				rto;
	u64			rtt_seq:48;
	struct timer_list	rtotimer;
	u64			rpseq;
	int			rpdupack;
	unsigned long		last_cong;
	u64			high_ack;
	struct list_head	av_chunks;
};

static inline bool ccid2_cwnd_network_limited(struct ccid2_hc_tx_sock *hctx)
{
	return (hctx->pipe >= hctx->cwnd);
}

struct ccid2_hc_rx_sock {
	int			data;
};

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_ */