net/dccp/ccids/ccid2.h

   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_ */