1*4882a593Smuzhiyun /* SPDX-License-Identifier: GPL-2.0-or-later */
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * Copyright (c) 2005 Andrea Bittau <a.bittau@cs.ucl.ac.uk>
4*4882a593Smuzhiyun */
5*4882a593Smuzhiyun #ifndef _DCCP_CCID2_H_
6*4882a593Smuzhiyun #define _DCCP_CCID2_H_
7*4882a593Smuzhiyun
8*4882a593Smuzhiyun #include <linux/timer.h>
9*4882a593Smuzhiyun #include <linux/types.h>
10*4882a593Smuzhiyun #include "../ccid.h"
11*4882a593Smuzhiyun #include "../dccp.h"
12*4882a593Smuzhiyun
13*4882a593Smuzhiyun /*
14*4882a593Smuzhiyun * CCID-2 timestamping faces the same issues as TCP timestamping.
15*4882a593Smuzhiyun * Hence we reuse/share as much of the code as possible.
16*4882a593Smuzhiyun */
17*4882a593Smuzhiyun #define ccid2_jiffies32 ((u32)jiffies)
18*4882a593Smuzhiyun
19*4882a593Smuzhiyun /* NUMDUPACK parameter from RFC 4341, p. 6 */
20*4882a593Smuzhiyun #define NUMDUPACK 3
21*4882a593Smuzhiyun
22*4882a593Smuzhiyun struct ccid2_seq {
23*4882a593Smuzhiyun u64 ccid2s_seq;
24*4882a593Smuzhiyun u32 ccid2s_sent;
25*4882a593Smuzhiyun int ccid2s_acked;
26*4882a593Smuzhiyun struct ccid2_seq *ccid2s_prev;
27*4882a593Smuzhiyun struct ccid2_seq *ccid2s_next;
28*4882a593Smuzhiyun };
29*4882a593Smuzhiyun
30*4882a593Smuzhiyun #define CCID2_SEQBUF_LEN 1024
31*4882a593Smuzhiyun #define CCID2_SEQBUF_MAX 128
32*4882a593Smuzhiyun
33*4882a593Smuzhiyun /*
34*4882a593Smuzhiyun * Multiple of congestion window to keep the sequence window at
35*4882a593Smuzhiyun * (RFC 4340 7.5.2)
36*4882a593Smuzhiyun */
37*4882a593Smuzhiyun #define CCID2_WIN_CHANGE_FACTOR 5
38*4882a593Smuzhiyun
39*4882a593Smuzhiyun /**
40*4882a593Smuzhiyun * struct ccid2_hc_tx_sock - CCID2 TX half connection
41*4882a593Smuzhiyun * @tx_{cwnd,ssthresh,pipe}: as per RFC 4341, section 5
42*4882a593Smuzhiyun * @tx_packets_acked: Ack counter for deriving cwnd growth (RFC 3465)
43*4882a593Smuzhiyun * @tx_srtt: smoothed RTT estimate, scaled by 2^3
44*4882a593Smuzhiyun * @tx_mdev: smoothed RTT variation, scaled by 2^2
45*4882a593Smuzhiyun * @tx_mdev_max: maximum of @mdev during one flight
46*4882a593Smuzhiyun * @tx_rttvar: moving average/maximum of @mdev_max
47*4882a593Smuzhiyun * @tx_rto: RTO value deriving from SRTT and RTTVAR (RFC 2988)
48*4882a593Smuzhiyun * @tx_rtt_seq: to decay RTTVAR at most once per flight
49*4882a593Smuzhiyun * @tx_cwnd_used: actually used cwnd, W_used of RFC 2861
50*4882a593Smuzhiyun * @tx_expected_wnd: moving average of @tx_cwnd_used
51*4882a593Smuzhiyun * @tx_cwnd_stamp: to track idle periods in CWV
52*4882a593Smuzhiyun * @tx_lsndtime: last time (in jiffies) a data packet was sent
53*4882a593Smuzhiyun * @tx_rpseq: last consecutive seqno
54*4882a593Smuzhiyun * @tx_rpdupack: dupacks since rpseq
55*4882a593Smuzhiyun * @tx_av_chunks: list of Ack Vectors received on current skb
56*4882a593Smuzhiyun */
57*4882a593Smuzhiyun struct ccid2_hc_tx_sock {
58*4882a593Smuzhiyun u32 tx_cwnd;
59*4882a593Smuzhiyun u32 tx_ssthresh;
60*4882a593Smuzhiyun u32 tx_pipe;
61*4882a593Smuzhiyun u32 tx_packets_acked;
62*4882a593Smuzhiyun struct ccid2_seq *tx_seqbuf[CCID2_SEQBUF_MAX];
63*4882a593Smuzhiyun int tx_seqbufc;
64*4882a593Smuzhiyun struct ccid2_seq *tx_seqh;
65*4882a593Smuzhiyun struct ccid2_seq *tx_seqt;
66*4882a593Smuzhiyun
67*4882a593Smuzhiyun /* RTT measurement: variables/principles are the same as in TCP */
68*4882a593Smuzhiyun u32 tx_srtt,
69*4882a593Smuzhiyun tx_mdev,
70*4882a593Smuzhiyun tx_mdev_max,
71*4882a593Smuzhiyun tx_rttvar,
72*4882a593Smuzhiyun tx_rto;
73*4882a593Smuzhiyun u64 tx_rtt_seq:48;
74*4882a593Smuzhiyun struct timer_list tx_rtotimer;
75*4882a593Smuzhiyun struct sock *sk;
76*4882a593Smuzhiyun
77*4882a593Smuzhiyun /* Congestion Window validation (optional, RFC 2861) */
78*4882a593Smuzhiyun u32 tx_cwnd_used,
79*4882a593Smuzhiyun tx_expected_wnd,
80*4882a593Smuzhiyun tx_cwnd_stamp,
81*4882a593Smuzhiyun tx_lsndtime;
82*4882a593Smuzhiyun
83*4882a593Smuzhiyun u64 tx_rpseq;
84*4882a593Smuzhiyun int tx_rpdupack;
85*4882a593Smuzhiyun u32 tx_last_cong;
86*4882a593Smuzhiyun u64 tx_high_ack;
87*4882a593Smuzhiyun struct list_head tx_av_chunks;
88*4882a593Smuzhiyun };
89*4882a593Smuzhiyun
ccid2_cwnd_network_limited(struct ccid2_hc_tx_sock * hc)90*4882a593Smuzhiyun static inline bool ccid2_cwnd_network_limited(struct ccid2_hc_tx_sock *hc)
91*4882a593Smuzhiyun {
92*4882a593Smuzhiyun return hc->tx_pipe >= hc->tx_cwnd;
93*4882a593Smuzhiyun }
94*4882a593Smuzhiyun
95*4882a593Smuzhiyun /*
96*4882a593Smuzhiyun * Convert RFC 3390 larger initial window into an equivalent number of packets.
97*4882a593Smuzhiyun * This is based on the numbers specified in RFC 5681, 3.1.
98*4882a593Smuzhiyun */
rfc3390_bytes_to_packets(const u32 smss)99*4882a593Smuzhiyun static inline u32 rfc3390_bytes_to_packets(const u32 smss)
100*4882a593Smuzhiyun {
101*4882a593Smuzhiyun return smss <= 1095 ? 4 : (smss > 2190 ? 2 : 3);
102*4882a593Smuzhiyun }
103*4882a593Smuzhiyun
104*4882a593Smuzhiyun /**
105*4882a593Smuzhiyun * struct ccid2_hc_rx_sock - Receiving end of CCID-2 half-connection
106*4882a593Smuzhiyun * @rx_num_data_pkts: number of data packets received since last feedback
107*4882a593Smuzhiyun */
108*4882a593Smuzhiyun struct ccid2_hc_rx_sock {
109*4882a593Smuzhiyun u32 rx_num_data_pkts;
110*4882a593Smuzhiyun };
111*4882a593Smuzhiyun
ccid2_hc_tx_sk(const struct sock * sk)112*4882a593Smuzhiyun static inline struct ccid2_hc_tx_sock *ccid2_hc_tx_sk(const struct sock *sk)
113*4882a593Smuzhiyun {
114*4882a593Smuzhiyun return ccid_priv(dccp_sk(sk)->dccps_hc_tx_ccid);
115*4882a593Smuzhiyun }
116*4882a593Smuzhiyun
ccid2_hc_rx_sk(const struct sock * sk)117*4882a593Smuzhiyun static inline struct ccid2_hc_rx_sock *ccid2_hc_rx_sk(const struct sock *sk)
118*4882a593Smuzhiyun {
119*4882a593Smuzhiyun return ccid_priv(dccp_sk(sk)->dccps_hc_rx_ccid);
120*4882a593Smuzhiyun }
121*4882a593Smuzhiyun #endif /* _DCCP_CCID2_H_ */
122