2005-08-10 23:59:38 +08:00
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/*
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2006-08-27 10:01:03 +08:00
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* net/dccp/packet_history.c
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2005-08-10 23:59:38 +08:00
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*
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2007-11-28 21:15:40 +08:00
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* Copyright (c) 2007 The University of Aberdeen, Scotland, UK
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* Copyright (c) 2005-7 The University of Waikato, Hamilton, New Zealand.
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2005-08-10 23:59:38 +08:00
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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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2006-08-27 10:01:30 +08:00
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* or e-mail Ian McDonald - ian.mcdonald@jandi.co.nz
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2005-08-10 23:59:38 +08:00
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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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#include <linux/string.h>
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2007-12-06 23:18:11 +08:00
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#include <linux/slab.h>
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2005-08-10 23:59:38 +08:00
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#include "packet_history.h"
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2007-12-06 23:18:11 +08:00
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#include "../../dccp.h"
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2005-08-10 23:59:38 +08:00
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2007-11-30 08:47:15 +08:00
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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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2006-12-10 10:24:33 +08:00
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/*
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2007-11-28 21:15:40 +08:00
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* Transmitter History Routines
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2006-12-10 10:24:33 +08:00
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*/
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2007-12-06 22:27:49 +08:00
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static struct kmem_cache *tfrc_tx_hist_slab;
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2006-12-10 10:24:33 +08:00
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2007-11-30 08:47:15 +08:00
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static struct tfrc_tx_hist_entry *
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2007-11-28 21:15:40 +08:00
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tfrc_tx_hist_find_entry(struct tfrc_tx_hist_entry *head, u64 seqno)
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2006-12-10 10:24:33 +08:00
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{
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2007-11-28 21:15:40 +08:00
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while (head != NULL && head->seqno != seqno)
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head = head->next;
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2006-12-10 10:24:33 +08:00
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2007-11-28 21:15:40 +08:00
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return head;
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2006-12-10 10:24:33 +08:00
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}
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2007-11-28 21:15:40 +08:00
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int tfrc_tx_hist_add(struct tfrc_tx_hist_entry **headp, u64 seqno)
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2006-12-10 10:24:33 +08:00
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{
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2007-12-06 22:27:49 +08:00
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struct tfrc_tx_hist_entry *entry = kmem_cache_alloc(tfrc_tx_hist_slab, gfp_any());
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2007-11-28 21:15:40 +08:00
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if (entry == NULL)
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return -ENOBUFS;
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entry->seqno = seqno;
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entry->stamp = ktime_get_real();
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entry->next = *headp;
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*headp = entry;
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return 0;
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2006-12-10 10:24:33 +08:00
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}
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2007-11-28 21:15:40 +08:00
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EXPORT_SYMBOL_GPL(tfrc_tx_hist_add);
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2006-12-10 10:24:33 +08:00
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2007-11-28 21:15:40 +08:00
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void tfrc_tx_hist_purge(struct tfrc_tx_hist_entry **headp)
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2006-12-10 10:24:33 +08:00
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{
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2007-11-28 21:15:40 +08:00
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struct tfrc_tx_hist_entry *head = *headp;
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2006-12-10 10:24:33 +08:00
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2007-11-28 21:15:40 +08:00
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while (head != NULL) {
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struct tfrc_tx_hist_entry *next = head->next;
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2006-12-10 10:24:33 +08:00
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2007-12-06 22:27:49 +08:00
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kmem_cache_free(tfrc_tx_hist_slab, head);
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2007-11-28 21:15:40 +08:00
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head = next;
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2006-12-10 10:24:33 +08:00
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}
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2007-11-28 21:15:40 +08:00
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*headp = NULL;
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}
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EXPORT_SYMBOL_GPL(tfrc_tx_hist_purge);
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2006-12-10 10:24:33 +08:00
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2007-11-30 08:47:15 +08:00
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u32 tfrc_tx_hist_rtt(struct tfrc_tx_hist_entry *head, const u64 seqno,
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const ktime_t now)
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{
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u32 rtt = 0;
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struct tfrc_tx_hist_entry *packet = tfrc_tx_hist_find_entry(head, seqno);
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if (packet != NULL) {
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rtt = ktime_us_delta(now, packet->stamp);
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/*
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* Garbage-collect older (irrelevant) entries:
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*/
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tfrc_tx_hist_purge(&packet->next);
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}
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return rtt;
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}
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EXPORT_SYMBOL_GPL(tfrc_tx_hist_rtt);
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2007-12-06 23:18:11 +08:00
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2007-12-09 01:08:08 +08:00
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/*
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* Receiver History Routines
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*/
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static struct kmem_cache *tfrc_rx_hist_slab;
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2007-12-06 23:18:11 +08:00
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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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void tfrc_rx_hist_add_packet(struct tfrc_rx_hist *h,
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const struct sk_buff *skb,
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const u32 ndp)
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2005-08-10 23:59:38 +08:00
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{
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2007-12-06 23:18:11 +08:00
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struct tfrc_rx_hist_entry *entry = tfrc_rx_hist_last_rcv(h);
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const struct dccp_hdr *dh = dccp_hdr(skb);
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entry->tfrchrx_seqno = DCCP_SKB_CB(skb)->dccpd_seq;
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entry->tfrchrx_ccval = dh->dccph_ccval;
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entry->tfrchrx_type = dh->dccph_type;
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entry->tfrchrx_ndp = ndp;
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entry->tfrchrx_tstamp = ktime_get_real();
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2005-08-10 23:59:38 +08:00
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}
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2007-12-06 23:18:11 +08:00
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EXPORT_SYMBOL_GPL(tfrc_rx_hist_add_packet);
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2005-08-10 23:59:38 +08:00
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2007-12-06 23:18:11 +08:00
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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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2005-08-10 23:59:38 +08:00
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{
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2007-12-06 23:18:11 +08:00
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return h->ring[tfrc_rx_hist_index(h, n)];
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}
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2005-08-10 23:59:38 +08:00
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2007-12-06 23:18:11 +08:00
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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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/* has the packet contained in skb been seen before? */
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int tfrc_rx_hist_duplicate(struct tfrc_rx_hist *h, struct sk_buff *skb)
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{
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const u64 seq = DCCP_SKB_CB(skb)->dccpd_seq;
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int i;
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if (dccp_delta_seqno(tfrc_rx_hist_loss_prev(h)->tfrchrx_seqno, seq) <= 0)
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return 1;
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2005-08-10 23:59:38 +08:00
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2007-12-06 23:18:11 +08:00
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for (i = 1; i <= h->loss_count; i++)
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if (tfrc_rx_hist_entry(h, i)->tfrchrx_seqno == seq)
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return 1;
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2005-08-10 23:59:38 +08:00
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2007-12-06 23:18:11 +08:00
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return 0;
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2006-12-10 10:24:33 +08:00
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}
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2007-12-06 23:18:11 +08:00
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EXPORT_SYMBOL_GPL(tfrc_rx_hist_duplicate);
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2006-12-10 10:24:33 +08:00
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2007-12-06 23:18:11 +08:00
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/* initialise loss detection and disable RTT sampling */
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static inline void tfrc_rx_hist_loss_indicated(struct tfrc_rx_hist *h)
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2005-08-10 23:59:38 +08:00
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{
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2007-12-06 23:18:11 +08:00
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h->loss_count = 1;
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}
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2005-08-10 23:59:38 +08:00
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2007-12-06 23:18:11 +08:00
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/* indicate whether previously a packet was detected missing */
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static inline int tfrc_rx_hist_loss_pending(const struct tfrc_rx_hist *h)
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{
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return h->loss_count;
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}
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/* any data packets missing between last reception and skb ? */
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int tfrc_rx_hist_new_loss_indicated(struct tfrc_rx_hist *h,
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const struct sk_buff *skb, u32 ndp)
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{
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int delta = dccp_delta_seqno(tfrc_rx_hist_last_rcv(h)->tfrchrx_seqno,
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DCCP_SKB_CB(skb)->dccpd_seq);
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if (delta > 1 && ndp < delta)
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tfrc_rx_hist_loss_indicated(h);
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2005-08-10 23:59:38 +08:00
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2007-12-06 23:18:11 +08:00
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return tfrc_rx_hist_loss_pending(h);
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2005-08-10 23:59:38 +08:00
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}
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2007-12-06 23:18:11 +08:00
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EXPORT_SYMBOL_GPL(tfrc_rx_hist_new_loss_indicated);
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2005-08-10 23:59:38 +08:00
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2007-12-06 23:18:11 +08:00
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int tfrc_rx_hist_alloc(struct tfrc_rx_hist *h)
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{
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int i;
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for (i = 0; i <= TFRC_NDUPACK; i++) {
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h->ring[i] = kmem_cache_alloc(tfrc_rx_hist_slab, GFP_ATOMIC);
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if (h->ring[i] == NULL)
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goto out_free;
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}
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h->loss_count = h->loss_start = 0;
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return 0;
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out_free:
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while (i-- != 0) {
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kmem_cache_free(tfrc_rx_hist_slab, h->ring[i]);
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h->ring[i] = NULL;
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}
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return -ENOBUFS;
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}
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EXPORT_SYMBOL_GPL(tfrc_rx_hist_alloc);
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2005-08-10 23:59:38 +08:00
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2007-12-06 23:18:11 +08:00
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void tfrc_rx_hist_purge(struct tfrc_rx_hist *h)
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2005-08-28 12:19:14 +08:00
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{
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2007-12-06 23:18:11 +08:00
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int i;
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for (i = 0; i <= TFRC_NDUPACK; ++i)
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if (h->ring[i] != NULL) {
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kmem_cache_free(tfrc_rx_hist_slab, h->ring[i]);
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h->ring[i] = NULL;
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2005-08-28 12:19:14 +08:00
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}
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}
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2007-12-06 23:18:11 +08:00
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EXPORT_SYMBOL_GPL(tfrc_rx_hist_purge);
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2005-08-28 12:19:14 +08:00
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2007-12-06 23:18:11 +08:00
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/**
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* tfrc_rx_hist_rtt_last_s - reference entry to compute RTT samples against
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*/
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static inline struct tfrc_rx_hist_entry *
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tfrc_rx_hist_rtt_last_s(const struct tfrc_rx_hist *h)
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{
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return h->ring[0];
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}
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2005-08-28 12:19:14 +08:00
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2007-12-06 23:18:11 +08:00
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/**
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* tfrc_rx_hist_rtt_prev_s: previously suitable (wrt rtt_last_s) RTT-sampling entry
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*/
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static inline struct tfrc_rx_hist_entry *
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tfrc_rx_hist_rtt_prev_s(const struct tfrc_rx_hist *h)
|
2005-08-10 23:59:38 +08:00
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{
|
2007-12-06 23:18:11 +08:00
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return h->ring[h->rtt_sample_prev];
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}
|
2005-08-10 23:59:38 +08:00
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2007-12-06 23:18:11 +08:00
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/**
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* tfrc_rx_hist_sample_rtt - Sample RTT from timestamp / CCVal
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* Based on ideas presented in RFC 4342, 8.1. Returns 0 if it was not able
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* to compute a sample with given data - calling function should check this.
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*/
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u32 tfrc_rx_hist_sample_rtt(struct tfrc_rx_hist *h, const struct sk_buff *skb)
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{
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u32 sample = 0,
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delta_v = SUB16(dccp_hdr(skb)->dccph_ccval,
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tfrc_rx_hist_rtt_last_s(h)->tfrchrx_ccval);
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if (delta_v < 1 || delta_v > 4) { /* unsuitable CCVal delta */
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if (h->rtt_sample_prev == 2) { /* previous candidate stored */
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sample = SUB16(tfrc_rx_hist_rtt_prev_s(h)->tfrchrx_ccval,
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tfrc_rx_hist_rtt_last_s(h)->tfrchrx_ccval);
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if (sample)
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sample = 4 / sample *
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ktime_us_delta(tfrc_rx_hist_rtt_prev_s(h)->tfrchrx_tstamp,
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tfrc_rx_hist_rtt_last_s(h)->tfrchrx_tstamp);
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else /*
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* FIXME: This condition is in principle not
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* possible but occurs when CCID is used for
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* two-way data traffic. I have tried to trace
|
|
|
|
* it, but the cause does not seem to be here.
|
|
|
|
*/
|
|
|
|
DCCP_BUG("please report to dccp@vger.kernel.org"
|
|
|
|
" => prev = %u, last = %u",
|
|
|
|
tfrc_rx_hist_rtt_prev_s(h)->tfrchrx_ccval,
|
|
|
|
tfrc_rx_hist_rtt_last_s(h)->tfrchrx_ccval);
|
|
|
|
} else if (delta_v < 1) {
|
|
|
|
h->rtt_sample_prev = 1;
|
|
|
|
goto keep_ref_for_next_time;
|
|
|
|
}
|
|
|
|
|
|
|
|
} else if (delta_v == 4) /* optimal match */
|
|
|
|
sample = ktime_to_us(net_timedelta(tfrc_rx_hist_rtt_last_s(h)->tfrchrx_tstamp));
|
|
|
|
else { /* suboptimal match */
|
|
|
|
h->rtt_sample_prev = 2;
|
|
|
|
goto keep_ref_for_next_time;
|
2005-08-10 23:59:38 +08:00
|
|
|
}
|
|
|
|
|
2007-12-06 23:18:11 +08:00
|
|
|
if (unlikely(sample > DCCP_SANE_RTT_MAX)) {
|
|
|
|
DCCP_WARN("RTT sample %u too large, using max\n", sample);
|
|
|
|
sample = DCCP_SANE_RTT_MAX;
|
|
|
|
}
|
|
|
|
|
|
|
|
h->rtt_sample_prev = 0; /* use current entry as next reference */
|
|
|
|
keep_ref_for_next_time:
|
|
|
|
|
|
|
|
return sample;
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL_GPL(tfrc_rx_hist_sample_rtt);
|
2005-08-10 23:59:38 +08:00
|
|
|
|
2007-12-06 22:26:38 +08:00
|
|
|
__init int packet_history_init(void)
|
2007-11-28 21:15:40 +08:00
|
|
|
{
|
2007-12-06 22:27:49 +08:00
|
|
|
tfrc_tx_hist_slab = kmem_cache_create("tfrc_tx_hist",
|
|
|
|
sizeof(struct tfrc_tx_hist_entry), 0,
|
|
|
|
SLAB_HWCACHE_ALIGN, NULL);
|
2007-12-06 22:28:13 +08:00
|
|
|
if (tfrc_tx_hist_slab == NULL)
|
|
|
|
goto out_err;
|
2007-11-28 21:15:40 +08:00
|
|
|
|
2007-12-06 22:28:13 +08:00
|
|
|
tfrc_rx_hist_slab = kmem_cache_create("tfrc_rx_hist",
|
2007-12-06 22:28:39 +08:00
|
|
|
sizeof(struct tfrc_rx_hist_entry), 0,
|
2007-12-06 22:28:13 +08:00
|
|
|
SLAB_HWCACHE_ALIGN, NULL);
|
|
|
|
if (tfrc_rx_hist_slab == NULL)
|
|
|
|
goto out_free_tx;
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
out_free_tx:
|
|
|
|
kmem_cache_destroy(tfrc_tx_hist_slab);
|
|
|
|
tfrc_tx_hist_slab = NULL;
|
|
|
|
out_err:
|
|
|
|
return -ENOBUFS;
|
2007-11-28 21:15:40 +08:00
|
|
|
}
|
|
|
|
|
2007-12-06 22:26:38 +08:00
|
|
|
void packet_history_exit(void)
|
2007-11-28 21:15:40 +08:00
|
|
|
{
|
2007-12-06 22:27:49 +08:00
|
|
|
if (tfrc_tx_hist_slab != NULL) {
|
|
|
|
kmem_cache_destroy(tfrc_tx_hist_slab);
|
|
|
|
tfrc_tx_hist_slab = NULL;
|
2007-11-28 21:15:40 +08:00
|
|
|
}
|
2007-12-06 22:28:13 +08:00
|
|
|
|
|
|
|
if (tfrc_rx_hist_slab != NULL) {
|
|
|
|
kmem_cache_destroy(tfrc_rx_hist_slab);
|
|
|
|
tfrc_rx_hist_slab = NULL;
|
|
|
|
}
|
2007-11-28 21:15:40 +08:00
|
|
|
}
|