net/dccp/ccids/ccid2.h

   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
 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  */
 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
 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
 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_ */