8a9c7e92e0
A ringbuffer-based implementation of loss interval history is easier to maintain, allocate, and update. The `swap' routine to keep the RX history sorted is due to and was written by Arnaldo Carvalho de Melo, simplifying an earlier macro-based variant. Details: * access to the Loss Interval Records via macro wrappers (with safety checks); * simplified, on-demand allocation of entries (no extra memory consumption on lossless links); cache allocation is local to the module / exported as service; * provision of RFC-compliant algorithm to re-compute average loss interval; * provision of comprehensive, new loss detection algorithm - support for all cases of loss, including re-ordered/duplicate packets; - waiting for NDUPACK=3 packets to fill the hole; - updating loss records when a late-arriving packet fills a hole. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> Signed-off-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>
65 lines
1.8 KiB
C
65 lines
1.8 KiB
C
#ifndef _TFRC_H_
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#define _TFRC_H_
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/*
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* net/dccp/ccids/lib/tfrc.h
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*
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* Copyright (c) 2007 The University of Aberdeen, Scotland, UK
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* Copyright (c) 2005-6 The University of Waikato, Hamilton, New Zealand.
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* Copyright (c) 2005-6 Ian McDonald <ian.mcdonald@jandi.co.nz>
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* Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
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* Copyright (c) 2003 Nils-Erik Mattsson, Joacim Haggmark, Magnus Erixzon
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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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#include <linux/types.h>
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#include <asm/div64.h>
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#include "../../dccp.h"
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/* internal includes that this module exports: */
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#include "loss_interval.h"
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#include "packet_history.h"
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#ifdef CONFIG_IP_DCCP_TFRC_DEBUG
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extern int tfrc_debug;
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#define tfrc_pr_debug(format, a...) DCCP_PR_DEBUG(tfrc_debug, format, ##a)
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#else
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#define tfrc_pr_debug(format, a...)
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#endif
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/* integer-arithmetic divisions of type (a * 1000000)/b */
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static inline u64 scaled_div(u64 a, u32 b)
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{
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BUG_ON(b==0);
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a *= 1000000;
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do_div(a, b);
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return a;
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}
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static inline u32 scaled_div32(u64 a, u32 b)
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{
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u64 result = scaled_div(a, b);
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if (result > UINT_MAX) {
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DCCP_CRIT("Overflow: a(%llu)/b(%u) > ~0U",
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(unsigned long long)a, b);
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return UINT_MAX;
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}
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return result;
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}
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/**
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* tfrc_ewma - Exponentially weighted moving average
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* @weight: Weight to be used as damping factor, in units of 1/10
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*/
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static inline u32 tfrc_ewma(const u32 avg, const u32 newval, const u8 weight)
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{
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return avg ? (weight * avg + (10 - weight) * newval) / 10 : newval;
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}
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extern u32 tfrc_calc_x(u16 s, u32 R, u32 p);
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extern u32 tfrc_calc_x_reverse_lookup(u32 fvalue);
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#endif /* _TFRC_H_ */
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