a402a5aa9b
There are a mix of function prototypes with and without extern in the kernel sources. Standardize on not using extern for function prototypes. Function prototypes don't need to be written with extern. extern is assumed by the compiler. Its use is as unnecessary as using auto to declare automatic/local variables in a block. Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: David S. Miller <davem@davemloft.net>
156 lines
5.0 KiB
C
156 lines
5.0 KiB
C
/*
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* Packet RX/TX history data structures and routines for TFRC-based protocols.
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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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*
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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_PKT_HIST_
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#define _DCCP_PKT_HIST_
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#include <linux/list.h>
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#include <linux/slab.h>
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#include "tfrc.h"
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/**
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* tfrc_tx_hist_entry - Simple singly-linked TX history list
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* @next: next oldest entry (LIFO order)
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* @seqno: sequence number of this entry
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* @stamp: send time of packet with sequence number @seqno
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*/
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struct tfrc_tx_hist_entry {
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struct tfrc_tx_hist_entry *next;
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u64 seqno;
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ktime_t stamp;
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};
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static inline struct tfrc_tx_hist_entry *
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tfrc_tx_hist_find_entry(struct tfrc_tx_hist_entry *head, u64 seqno)
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{
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while (head != NULL && head->seqno != seqno)
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head = head->next;
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return head;
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}
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int tfrc_tx_hist_add(struct tfrc_tx_hist_entry **headp, u64 seqno);
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void tfrc_tx_hist_purge(struct tfrc_tx_hist_entry **headp);
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/* Subtraction a-b modulo-16, respects circular wrap-around */
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#define SUB16(a, b) (((a) + 16 - (b)) & 0xF)
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/* Number of packets to wait after a missing packet (RFC 4342, 6.1) */
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#define TFRC_NDUPACK 3
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/**
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* tfrc_rx_hist_entry - Store information about a single received packet
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* @tfrchrx_seqno: DCCP packet sequence number
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* @tfrchrx_ccval: window counter value of packet (RFC 4342, 8.1)
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* @tfrchrx_ndp: the NDP count (if any) of the packet
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* @tfrchrx_tstamp: actual receive time of packet
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*/
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struct tfrc_rx_hist_entry {
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u64 tfrchrx_seqno:48,
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tfrchrx_ccval:4,
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tfrchrx_type:4;
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u64 tfrchrx_ndp:48;
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ktime_t tfrchrx_tstamp;
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};
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/**
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* tfrc_rx_hist - RX history structure for TFRC-based protocols
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* @ring: Packet history for RTT sampling and loss detection
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* @loss_count: Number of entries in circular history
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* @loss_start: Movable index (for loss detection)
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* @rtt_sample_prev: Used during RTT sampling, points to candidate entry
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*/
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struct tfrc_rx_hist {
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struct tfrc_rx_hist_entry *ring[TFRC_NDUPACK + 1];
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u8 loss_count:2,
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loss_start:2;
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#define rtt_sample_prev loss_start
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};
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/**
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* tfrc_rx_hist_index - index to reach n-th entry after loss_start
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*/
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static inline u8 tfrc_rx_hist_index(const struct tfrc_rx_hist *h, const u8 n)
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{
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return (h->loss_start + n) & TFRC_NDUPACK;
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}
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/**
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* tfrc_rx_hist_last_rcv - entry with highest-received-seqno so far
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*/
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static inline struct tfrc_rx_hist_entry *
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tfrc_rx_hist_last_rcv(const struct tfrc_rx_hist *h)
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{
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return h->ring[tfrc_rx_hist_index(h, h->loss_count)];
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}
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/**
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* tfrc_rx_hist_entry - return the n-th history entry after loss_start
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*/
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static inline struct tfrc_rx_hist_entry *
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tfrc_rx_hist_entry(const struct tfrc_rx_hist *h, const u8 n)
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{
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return h->ring[tfrc_rx_hist_index(h, n)];
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}
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/**
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* tfrc_rx_hist_loss_prev - entry with highest-received-seqno before loss was detected
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*/
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static inline struct tfrc_rx_hist_entry *
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tfrc_rx_hist_loss_prev(const struct tfrc_rx_hist *h)
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{
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return h->ring[h->loss_start];
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}
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/* indicate whether previously a packet was detected missing */
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static inline bool tfrc_rx_hist_loss_pending(const struct tfrc_rx_hist *h)
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{
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return h->loss_count > 0;
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}
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void tfrc_rx_hist_add_packet(struct tfrc_rx_hist *h, const struct sk_buff *skb,
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const u64 ndp);
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int tfrc_rx_hist_duplicate(struct tfrc_rx_hist *h, struct sk_buff *skb);
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struct tfrc_loss_hist;
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int tfrc_rx_handle_loss(struct tfrc_rx_hist *h, struct tfrc_loss_hist *lh,
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struct sk_buff *skb, const u64 ndp,
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u32 (*first_li)(struct sock *sk), struct sock *sk);
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u32 tfrc_rx_hist_sample_rtt(struct tfrc_rx_hist *h, const struct sk_buff *skb);
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int tfrc_rx_hist_alloc(struct tfrc_rx_hist *h);
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void tfrc_rx_hist_purge(struct tfrc_rx_hist *h);
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#endif /* _DCCP_PKT_HIST_ */
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