linux/net/dccp/ccids/ccid2.h
Gerrit Renker 900bfed471 [CCID2]: Disable broken Ack Ratio adaptation algorithm
This comments out a problematic section comprising a half-finished algorithm:

 - The variable `ccid2hctx_ackloss' is never initialised to a value different from 0 and
   hence in fact is a read-only constant.
 - The `arsent' variable counts packets other than Acks (it is incremented for every packet),
   and there is no test for Ack Loss.
 - The concept of counting Acks as such leads to a complex calculation, and the calculation
   at the moment is inconsistent with this concept.
   The problem is that the number of Acks - rather than the number of windows - is counted,
   which leads to a complex (cubic/quadratic) expression - this is not even implemented.

In its current state, the commented-out algorithm interfers with normal processing by
changing Ack Ratio incorrectly, and at the wrong times.

A new algorithm is necessary, which will not necessarily use the same variables as used by
the unfinished one; hence the old variables have been removed.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-01-28 14:54:55 -08:00

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/*
* net/dccp/ccids/ccid2.h
*
* Copyright (c) 2005 Andrea Bittau <a.bittau@cs.ucl.ac.uk>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#ifndef _DCCP_CCID2_H_
#define _DCCP_CCID2_H_
#include <linux/dccp.h>
#include <linux/timer.h>
#include <linux/types.h>
#include "../ccid.h"
struct sock;
struct ccid2_seq {
u64 ccid2s_seq;
unsigned long ccid2s_sent;
int ccid2s_acked;
struct ccid2_seq *ccid2s_prev;
struct ccid2_seq *ccid2s_next;
};
#define CCID2_SEQBUF_LEN 1024
#define CCID2_SEQBUF_MAX 128
/** struct ccid2_hc_tx_sock - CCID2 TX half connection
*
* @ccid2hctx_ssacks - ACKs recv in slow start
* @ccid2hctx_acks - ACKS recv in AI phase
* @ccid2hctx_sent - packets sent in this window
* @ccid2hctx_lastrtt -time RTT was last measured
* @ccid2hctx_rpseq - last consecutive seqno
* @ccid2hctx_rpdupack - dupacks since rpseq
*/
struct ccid2_hc_tx_sock {
u32 ccid2hctx_cwnd;
int ccid2hctx_ssacks;
int ccid2hctx_acks;
unsigned int ccid2hctx_ssthresh;
int ccid2hctx_pipe;
int ccid2hctx_numdupack;
struct ccid2_seq *ccid2hctx_seqbuf[CCID2_SEQBUF_MAX];
int ccid2hctx_seqbufc;
struct ccid2_seq *ccid2hctx_seqh;
struct ccid2_seq *ccid2hctx_seqt;
long ccid2hctx_rto;
long ccid2hctx_srtt;
long ccid2hctx_rttvar;
int ccid2hctx_sent;
unsigned long ccid2hctx_lastrtt;
struct timer_list ccid2hctx_rtotimer;
u64 ccid2hctx_rpseq;
int ccid2hctx_rpdupack;
int ccid2hctx_sendwait;
unsigned long ccid2hctx_last_cong;
u64 ccid2hctx_high_ack;
};
struct ccid2_hc_rx_sock {
int ccid2hcrx_data;
};
static inline struct ccid2_hc_tx_sock *ccid2_hc_tx_sk(const struct sock *sk)
{
return ccid_priv(dccp_sk(sk)->dccps_hc_tx_ccid);
}
static inline struct ccid2_hc_rx_sock *ccid2_hc_rx_sk(const struct sock *sk)
{
return ccid_priv(dccp_sk(sk)->dccps_hc_rx_ccid);
}
#endif /* _DCCP_CCID2_H_ */