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  * struct ccid2_hc_tx_sock - CCID2 TX half connection
  48  * @tx_{cwnd,ssthresh,pipe}: as per RFC 4341, section 5
  49  * @tx_packets_acked:        Ack counter for deriving cwnd growth (RFC 3465)
  50  * @tx_srtt:                 smoothed RTT estimate, scaled by 2^3
  51  * @tx_mdev:                 smoothed RTT variation, scaled by 2^2
  52  * @tx_mdev_max:             maximum of @mdev during one flight
  53  * @tx_rttvar:               moving average/maximum of @mdev_max
  54  * @tx_rto:                  RTO value deriving from SRTT and RTTVAR (RFC 2988)
  55  * @tx_rtt_seq:              to decay RTTVAR at most once per flight
  56  * @tx_cwnd_used:            actually used cwnd, W_used of RFC 2861
  57  * @tx_expected_wnd:         moving average of @tx_cwnd_used
  58  * @tx_cwnd_stamp:           to track idle periods in CWV
  59  * @tx_lsndtime:             last time (in jiffies) a data packet was sent
  60  * @tx_rpseq:                last consecutive seqno
  61  * @tx_rpdupack:             dupacks since rpseq
  62  * @tx_av_chunks:            list of Ack Vectors received on current skb
  63  */
  64 struct ccid2_hc_tx_sock {
  65         u32                     tx_cwnd;
  66         u32                     tx_ssthresh;
  67         u32                     tx_pipe;
  68         u32                     tx_packets_acked;
  69         struct ccid2_seq        *tx_seqbuf[CCID2_SEQBUF_MAX];
  70         int                     tx_seqbufc;
  71         struct ccid2_seq        *tx_seqh;
  72         struct ccid2_seq        *tx_seqt;
  73
  74         /* RTT measurement: variables/principles are the same as in TCP */
  75         u32                     tx_srtt,
  76                                 tx_mdev,
  77                                 tx_mdev_max,
  78                                 tx_rttvar,
  79                                 tx_rto;
  80         u64                     tx_rtt_seq:48;
  81         struct timer_list       tx_rtotimer;
  82
  83         /* Congestion Window validation (optional, RFC 2861) */
  84         u32                     tx_cwnd_used,
  85                                 tx_expected_wnd,
  86                                 tx_cwnd_stamp,
  87                                 tx_lsndtime;
  88
  89         u64                     tx_rpseq;
  90         int                     tx_rpdupack;
  91         u32                     tx_last_cong;
  92         u64                     tx_high_ack;
  93         struct list_head        tx_av_chunks;
  94 };
  95
  96 static inline bool ccid2_cwnd_network_limited(struct ccid2_hc_tx_sock *hc)
  97 {
  98         return hc->tx_pipe >= hc->tx_cwnd;
  99 }
 100
 101 /*
 102  * Convert RFC 3390 larger initial window into an equivalent number of packets.
 103  * This is based on the numbers specified in RFC 5681, 3.1.
 104  */
 105 static inline u32 rfc3390_bytes_to_packets(const u32 smss)
 106 {
 107         return smss <= 1095 ? 4 : (smss > 2190 ? 2 : 3);
 108 }
 109
 110 /**
 111  * struct ccid2_hc_rx_sock  -  Receiving end of CCID-2 half-connection
 112  * @rx_num_data_pkts: number of data packets received since last feedback
 113  */
 114 struct ccid2_hc_rx_sock {
 115         u32     rx_num_data_pkts;
 116 };
 117
 118 static inline struct ccid2_hc_tx_sock *ccid2_hc_tx_sk(const struct sock *sk)
 119 {
 120         return ccid_priv(dccp_sk(sk)->dccps_hc_tx_ccid);
 121 }
 122
 123 static inline struct ccid2_hc_rx_sock *ccid2_hc_rx_sk(const struct sock *sk)
 124 {
 125         return ccid_priv(dccp_sk(sk)->dccps_hc_rx_ccid);
 126 }
 127 #endif /* _DCCP_CCID2_H_ */