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80763dfbac
This patch is thanks to an investigation by Leandro Sales de Melo and his
colleagues. They worked out two state diagrams which highlight the fact that
the xxx_TERM states in CCID-3/4 are in fact not necessary.
And this can be confirmed by in turn looking at the code: the xxx_TERM states
are only ever set in ccid3_hc_{rx,tx}_exit(): when CCID-3 sets the state
to xxx_TERM, it is at a time where no more processing should be going on,
hence it is not necessary to introduce a dedicated exit state - this is already
implied by unloading the CCID.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
168 lines
5.6 KiB
C
168 lines
5.6 KiB
C
/*
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* Copyright (c) 2005-7 The University of Waikato, Hamilton, New Zealand.
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* Copyright (c) 2007 The University of Aberdeen, Scotland, UK
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*
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* An implementation of the DCCP protocol
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*
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* This code has been developed by the University of Waikato WAND
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* research group. For further information please see http://www.wand.net.nz/
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* or e-mail Ian McDonald - ian.mcdonald@jandi.co.nz
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*
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* This code also uses code from Lulea University, rereleased as GPL by its
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* authors:
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* Copyright (c) 2003 Nils-Erik Mattsson, Joacim Haggmark, Magnus Erixzon
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*
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* Changes to meet Linux coding standards, to make it meet latest ccid3 draft
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* and to make it work as a loadable module in the DCCP stack written by
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* Arnaldo Carvalho de Melo <acme@conectiva.com.br>.
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*
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* Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#ifndef _DCCP_CCID3_H_
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#define _DCCP_CCID3_H_
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#include <linux/ktime.h>
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#include <linux/list.h>
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#include <linux/types.h>
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#include <linux/tfrc.h>
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#include "lib/tfrc.h"
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#include "../ccid.h"
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/* Two seconds as per RFC 5348, 4.2 */
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#define TFRC_INITIAL_TIMEOUT (2 * USEC_PER_SEC)
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/* Parameter t_mbi from [RFC 3448, 4.3]: backoff interval in seconds */
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#define TFRC_T_MBI 64
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/*
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* The t_delta parameter (RFC 5348, 8.3): delays of less than %USEC_PER_MSEC are
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* rounded down to 0, since sk_reset_timer() here uses millisecond granularity.
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* Hence we can use a constant t_delta = %USEC_PER_MSEC when HZ >= 500. A coarse
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* resolution of HZ < 500 means that the error is below one timer tick (t_gran)
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* when using the constant t_delta = t_gran / 2 = %USEC_PER_SEC / (2 * HZ).
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*/
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#if (HZ >= 500)
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# define TFRC_T_DELTA USEC_PER_MSEC
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#else
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# define TFRC_T_DELTA (USEC_PER_SEC / (2 * HZ))
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#endif
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enum ccid3_options {
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TFRC_OPT_LOSS_EVENT_RATE = 192,
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TFRC_OPT_LOSS_INTERVALS = 193,
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TFRC_OPT_RECEIVE_RATE = 194,
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};
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struct ccid3_options_received {
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u32 ccid3or_loss_event_rate;
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u32 ccid3or_receive_rate;
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};
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/* TFRC sender states */
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enum ccid3_hc_tx_states {
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TFRC_SSTATE_NO_SENT = 1,
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TFRC_SSTATE_NO_FBACK,
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TFRC_SSTATE_FBACK,
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};
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/**
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* struct ccid3_hc_tx_sock - CCID3 sender half-connection socket
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* @tx_x: Current sending rate in 64 * bytes per second
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* @tx_x_recv: Receive rate in 64 * bytes per second
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* @tx_x_calc: Calculated rate in bytes per second
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* @tx_rtt: Estimate of current round trip time in usecs
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* @tx_p: Current loss event rate (0-1) scaled by 1000000
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* @tx_s: Packet size in bytes
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* @tx_t_rto: Nofeedback Timer setting in usecs
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* @tx_t_ipi: Interpacket (send) interval (RFC 3448, 4.6) in usecs
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* @tx_state: Sender state, one of %ccid3_hc_tx_states
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* @tx_last_win_count: Last window counter sent
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* @tx_t_last_win_count: Timestamp of earliest packet
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* with last_win_count value sent
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* @tx_no_feedback_timer: Handle to no feedback timer
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* @tx_t_ld: Time last doubled during slow start
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* @tx_t_nom: Nominal send time of next packet
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* @tx_hist: Packet history
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* @tx_options_received: Parsed set of retrieved options
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*/
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struct ccid3_hc_tx_sock {
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u64 tx_x;
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u64 tx_x_recv;
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u32 tx_x_calc;
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u32 tx_rtt;
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u32 tx_p;
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u32 tx_t_rto;
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u32 tx_t_ipi;
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u16 tx_s;
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enum ccid3_hc_tx_states tx_state:8;
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u8 tx_last_win_count;
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ktime_t tx_t_last_win_count;
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struct timer_list tx_no_feedback_timer;
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ktime_t tx_t_ld;
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ktime_t tx_t_nom;
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struct tfrc_tx_hist_entry *tx_hist;
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struct ccid3_options_received tx_options_received;
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};
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static inline struct ccid3_hc_tx_sock *ccid3_hc_tx_sk(const struct sock *sk)
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{
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struct ccid3_hc_tx_sock *hctx = ccid_priv(dccp_sk(sk)->dccps_hc_tx_ccid);
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BUG_ON(hctx == NULL);
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return hctx;
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}
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/* TFRC receiver states */
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enum ccid3_hc_rx_states {
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TFRC_RSTATE_NO_DATA = 1,
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TFRC_RSTATE_DATA,
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};
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/**
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* struct ccid3_hc_rx_sock - CCID3 receiver half-connection socket
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* @rx_last_counter: Tracks window counter (RFC 4342, 8.1)
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* @rx_state: Receiver state, one of %ccid3_hc_rx_states
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* @rx_bytes_recv: Total sum of DCCP payload bytes
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* @rx_x_recv: Receiver estimate of send rate (RFC 3448, sec. 4.3)
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* @rx_rtt: Receiver estimate of RTT
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* @rx_tstamp_last_feedback: Time at which last feedback was sent
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* @rx_hist: Packet history (loss detection + RTT sampling)
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* @rx_li_hist: Loss Interval database
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* @rx_s: Received packet size in bytes
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* @rx_pinv: Inverse of Loss Event Rate (RFC 4342, sec. 8.5)
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*/
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struct ccid3_hc_rx_sock {
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u8 rx_last_counter:4;
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enum ccid3_hc_rx_states rx_state:8;
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u32 rx_bytes_recv;
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u32 rx_x_recv;
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u32 rx_rtt;
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ktime_t rx_tstamp_last_feedback;
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struct tfrc_rx_hist rx_hist;
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struct tfrc_loss_hist rx_li_hist;
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u16 rx_s;
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#define rx_pinv rx_li_hist.i_mean
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};
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static inline struct ccid3_hc_rx_sock *ccid3_hc_rx_sk(const struct sock *sk)
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{
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struct ccid3_hc_rx_sock *hcrx = ccid_priv(dccp_sk(sk)->dccps_hc_rx_ccid);
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BUG_ON(hcrx == NULL);
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return hcrx;
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}
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#endif /* _DCCP_CCID3_H_ */
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