1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /*
3 * Copyright (c) 2005 Andrea Bittau <a.bittau@cs.ucl.ac.uk>
4 */
5 #ifndef _DCCP_CCID2_H_
6 #define _DCCP_CCID2_H_
7
8 #include <linux/timer.h>
9 #include <linux/types.h>
10 #include "../ccid.h"
11 #include "../dccp.h"
12
13 /*
14 * CCID-2 timestamping faces the same issues as TCP timestamping.
15 * Hence we reuse/share as much of the code as possible.
16 */
17 #define ccid2_jiffies32 ((u32)jiffies)
18
19 /* NUMDUPACK parameter from RFC 4341, p. 6 */
20 #define NUMDUPACK 3
21
22 struct ccid2_seq {
23 u64 ccid2s_seq;
24 u32 ccid2s_sent;
25 int ccid2s_acked;
26 struct ccid2_seq *ccid2s_prev;
27 struct ccid2_seq *ccid2s_next;
28 };
29
30 #define CCID2_SEQBUF_LEN 1024
31 #define CCID2_SEQBUF_MAX 128
32
33 /*
34 * Multiple of congestion window to keep the sequence window at
35 * (RFC 4340 7.5.2)
36 */
37 #define CCID2_WIN_CHANGE_FACTOR 5
38
39 /**
40 * struct ccid2_hc_tx_sock - CCID2 TX half connection
41 * @tx_{cwnd,ssthresh,pipe}: as per RFC 4341, section 5
42 * @tx_packets_acked: Ack counter for deriving cwnd growth (RFC 3465)
43 * @tx_srtt: smoothed RTT estimate, scaled by 2^3
44 * @tx_mdev: smoothed RTT variation, scaled by 2^2
45 * @tx_mdev_max: maximum of @mdev during one flight
46 * @tx_rttvar: moving average/maximum of @mdev_max
47 * @tx_rto: RTO value deriving from SRTT and RTTVAR (RFC 2988)
48 * @tx_rtt_seq: to decay RTTVAR at most once per flight
49 * @tx_cwnd_used: actually used cwnd, W_used of RFC 2861
50 * @tx_expected_wnd: moving average of @tx_cwnd_used
51 * @tx_cwnd_stamp: to track idle periods in CWV
52 * @tx_lsndtime: last time (in jiffies) a data packet was sent
53 * @tx_rpseq: last consecutive seqno
54 * @tx_rpdupack: dupacks since rpseq
55 * @tx_av_chunks: list of Ack Vectors received on current skb
56 */
57 struct ccid2_hc_tx_sock {
58 u32 tx_cwnd;
59 u32 tx_ssthresh;
60 u32 tx_pipe;
61 u32 tx_packets_acked;
62 struct ccid2_seq *tx_seqbuf[CCID2_SEQBUF_MAX];
63 int tx_seqbufc;
64 struct ccid2_seq *tx_seqh;
65 struct ccid2_seq *tx_seqt;
66
67 /* RTT measurement: variables/principles are the same as in TCP */
68 u32 tx_srtt,
69 tx_mdev,
70 tx_mdev_max,
71 tx_rttvar,
72 tx_rto;
73 u64 tx_rtt_seq:48;
74 struct timer_list tx_rtotimer;
75 struct sock *sk;
76
77 /* Congestion Window validation (optional, RFC 2861) */
78 u32 tx_cwnd_used,
79 tx_expected_wnd,
80 tx_cwnd_stamp,
81 tx_lsndtime;
82
83 u64 tx_rpseq;
84 int tx_rpdupack;
85 u32 tx_last_cong;
86 u64 tx_high_ack;
87 struct list_head tx_av_chunks;
88 };
89
90 static inline bool ccid2_cwnd_network_limited(struct ccid2_hc_tx_sock *hc)
91 {
92 return hc->tx_pipe >= hc->tx_cwnd;
93 }
94
95 /*
96 * Convert RFC 3390 larger initial window into an equivalent number of packets.
97 * This is based on the numbers specified in RFC 5681, 3.1.
98 */
99 static inline u32 rfc3390_bytes_to_packets(const u32 smss)
100 {
101 return smss <= 1095 ? 4 : (smss > 2190 ? 2 : 3);
102 }
103
104 /**
105 * struct ccid2_hc_rx_sock - Receiving end of CCID-2 half-connection
106 * @rx_num_data_pkts: number of data packets received since last feedback
107 */
108 struct ccid2_hc_rx_sock {
109 u32 rx_num_data_pkts;
110 };
111
112 static inline struct ccid2_hc_tx_sock *ccid2_hc_tx_sk(const struct sock *sk)
113 {
114 return ccid_priv(dccp_sk(sk)->dccps_hc_tx_ccid);
115 }
116
117 static inline struct ccid2_hc_rx_sock *ccid2_hc_rx_sk(const struct sock *sk)
118 {
119 return ccid_priv(dccp_sk(sk)->dccps_hc_rx_ccid);
120 }
121 #endif /* _DCCP_CCID2_H_ */