1 /*
2 * Copyright (c) 2005 Andrea Bittau <a.bittau@cs.ucl.ac.uk>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
17 */
18 #ifndef _DCCP_CCID2_H_
19 #define _DCCP_CCID2_H_
20
21 #include <linux/timer.h>
22 #include <linux/types.h>
23 #include "../ccid.h"
24 #include "../dccp.h"
25
26 /*
27 * CCID-2 timestamping faces the same issues as TCP timestamping.
28 * Hence we reuse/share as much of the code as possible.
29 */
30 #define ccid2_time_stamp tcp_time_stamp
31
32 /* NUMDUPACK parameter from RFC 4341, p. 6 */
33 #define NUMDUPACK 3
34
35 struct ccid2_seq {
36 u64 ccid2s_seq;
37 u32 ccid2s_sent;
38 int ccid2s_acked;
39 struct ccid2_seq *ccid2s_prev;
40 struct ccid2_seq *ccid2s_next;
41 };
42
43 #define CCID2_SEQBUF_LEN 1024
44 #define CCID2_SEQBUF_MAX 128
45
46 /*
47 * Multiple of congestion window to keep the sequence window at
48 * (RFC 4340 7.5.2)
49 */
50 #define CCID2_WIN_CHANGE_FACTOR 5
51
52 /**
53 * struct ccid2_hc_tx_sock - CCID2 TX half connection
54 * @tx_{cwnd,ssthresh,pipe}: as per RFC 4341, section 5
55 * @tx_packets_acked: Ack counter for deriving cwnd growth (RFC 3465)
56 * @tx_srtt: smoothed RTT estimate, scaled by 2^3
57 * @tx_mdev: smoothed RTT variation, scaled by 2^2
58 * @tx_mdev_max: maximum of @mdev during one flight
59 * @tx_rttvar: moving average/maximum of @mdev_max
60 * @tx_rto: RTO value deriving from SRTT and RTTVAR (RFC 2988)
61 * @tx_rtt_seq: to decay RTTVAR at most once per flight
62 * @tx_cwnd_used: actually used cwnd, W_used of RFC 2861
63 * @tx_expected_wnd: moving average of @tx_cwnd_used
64 * @tx_cwnd_stamp: to track idle periods in CWV
65 * @tx_lsndtime: last time (in jiffies) a data packet was sent
66 * @tx_rpseq: last consecutive seqno
67 * @tx_rpdupack: dupacks since rpseq
68 * @tx_av_chunks: list of Ack Vectors received on current skb
69 */
70 struct ccid2_hc_tx_sock {
71 u32 tx_cwnd;
72 u32 tx_ssthresh;
73 u32 tx_pipe;
74 u32 tx_packets_acked;
75 struct ccid2_seq *tx_seqbuf[CCID2_SEQBUF_MAX];
76 int tx_seqbufc;
77 struct ccid2_seq *tx_seqh;
78 struct ccid2_seq *tx_seqt;
79
80 /* RTT measurement: variables/principles are the same as in TCP */
81 u32 tx_srtt,
82 tx_mdev,
83 tx_mdev_max,
84 tx_rttvar,
85 tx_rto;
86 u64 tx_rtt_seq:48;
87 struct timer_list tx_rtotimer;
88
89 /* Congestion Window validation (optional, RFC 2861) */
90 u32 tx_cwnd_used,
91 tx_expected_wnd,
92 tx_cwnd_stamp,
93 tx_lsndtime;
94
95 u64 tx_rpseq;
96 int tx_rpdupack;
97 u32 tx_last_cong;
98 u64 tx_high_ack;
99 struct list_head tx_av_chunks;
100 };
101
ccid2_cwnd_network_limited(struct ccid2_hc_tx_sock * hc)102 static inline bool ccid2_cwnd_network_limited(struct ccid2_hc_tx_sock *hc)
103 {
104 return hc->tx_pipe >= hc->tx_cwnd;
105 }
106
107 /*
108 * Convert RFC 3390 larger initial window into an equivalent number of packets.
109 * This is based on the numbers specified in RFC 5681, 3.1.
110 */
rfc3390_bytes_to_packets(const u32 smss)111 static inline u32 rfc3390_bytes_to_packets(const u32 smss)
112 {
113 return smss <= 1095 ? 4 : (smss > 2190 ? 2 : 3);
114 }
115
116 /**
117 * struct ccid2_hc_rx_sock - Receiving end of CCID-2 half-connection
118 * @rx_num_data_pkts: number of data packets received since last feedback
119 */
120 struct ccid2_hc_rx_sock {
121 u32 rx_num_data_pkts;
122 };
123
ccid2_hc_tx_sk(const struct sock * sk)124 static inline struct ccid2_hc_tx_sock *ccid2_hc_tx_sk(const struct sock *sk)
125 {
126 return ccid_priv(dccp_sk(sk)->dccps_hc_tx_ccid);
127 }
128
ccid2_hc_rx_sk(const struct sock * sk)129 static inline struct ccid2_hc_rx_sock *ccid2_hc_rx_sk(const struct sock *sk)
130 {
131 return ccid_priv(dccp_sk(sk)->dccps_hc_rx_ccid);
132 }
133 #endif /* _DCCP_CCID2_H_ */
134