summaryrefslogtreecommitdiffstats
path: root/kernel/net/dccp/ccids/ccid2.h
blob: 18c97543e522a6b9a5c8a3c817d4b40224adde48 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
/*
 *  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/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 - CCID2 TX half connection
 * @tx_{cwnd,ssthresh,pipe}: as per RFC 4341, section 5
 * @tx_packets_acked:	     Ack counter for deriving cwnd growth (RFC 3465)
 * @tx_srtt:		     smoothed RTT estimate, scaled by 2^3
 * @tx_mdev:		     smoothed RTT variation, scaled by 2^2
 * @tx_mdev_max:	     maximum of @mdev during one flight
 * @tx_rttvar:		     moving average/maximum of @mdev_max
 * @tx_rto:		     RTO value deriving from SRTT and RTTVAR (RFC 2988)
 * @tx_rtt_seq:		     to decay RTTVAR at most once per flight
 * @tx_cwnd_used:	     actually used cwnd, W_used of RFC 2861
 * @tx_expected_wnd:	     moving average of @tx_cwnd_used
 * @tx_cwnd_stamp:	     to track idle periods in CWV
 * @tx_lsndtime:	     last time (in jiffies) a data packet was sent
 * @tx_rpseq:		     last consecutive seqno
 * @tx_rpdupack:	     dupacks since rpseq
 * @tx_av_chunks:	     list of Ack Vectors received on current skb
 */
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  -  Receiving end of CCID-2 half-connection
 * @rx_num_data_pkts: number of data packets received since last feedback
 */
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_ */