2005-04-16 16:20:36 -06:00
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/*
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* net/sched/sch_red.c Random Early Detection queue.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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* Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
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*
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* Changes:
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* J Hadi Salim <hadi@nortel.com> 980914: computation fixes
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* Alexey Makarenko <makar@phoenix.kharkov.ua> 990814: qave on idle link was calculated incorrectly.
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* J Hadi Salim <hadi@nortelnetworks.com> 980816: ECN support
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*/
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#include <linux/config.h>
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#include <linux/module.h>
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#include <asm/uaccess.h>
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#include <asm/system.h>
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#include <linux/bitops.h>
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/string.h>
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#include <linux/mm.h>
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#include <linux/socket.h>
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#include <linux/sockios.h>
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#include <linux/in.h>
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#include <linux/errno.h>
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#include <linux/interrupt.h>
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#include <linux/if_ether.h>
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#include <linux/inet.h>
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#include <linux/netdevice.h>
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#include <linux/etherdevice.h>
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#include <linux/notifier.h>
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#include <net/ip.h>
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#include <net/route.h>
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#include <linux/skbuff.h>
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#include <net/sock.h>
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#include <net/pkt_sched.h>
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#include <net/inet_ecn.h>
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#include <net/dsfield.h>
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2005-11-05 13:14:05 -07:00
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#include <net/red.h>
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2005-04-16 16:20:36 -06:00
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2005-11-05 13:14:05 -07:00
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/* Parameters, settable by user:
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2005-04-16 16:20:36 -06:00
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-----------------------------
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limit - bytes (must be > qth_max + burst)
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Hard limit on queue length, should be chosen >qth_max
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to allow packet bursts. This parameter does not
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affect the algorithms behaviour and can be chosen
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arbitrarily high (well, less than ram size)
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Really, this limit will never be reached
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if RED works correctly.
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*/
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struct red_sched_data
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{
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2005-11-05 13:14:05 -07:00
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u32 limit; /* HARD maximal queue length */
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unsigned char flags;
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struct red_parms parms;
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struct red_stats stats;
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2005-04-16 16:20:36 -06:00
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};
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2005-11-05 13:14:05 -07:00
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static inline int red_use_ecn(struct red_sched_data *q)
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2005-04-16 16:20:36 -06:00
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{
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2005-11-05 13:14:05 -07:00
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return q->flags & TC_RED_ECN;
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2005-04-16 16:20:36 -06:00
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}
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static int
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red_enqueue(struct sk_buff *skb, struct Qdisc* sch)
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{
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struct red_sched_data *q = qdisc_priv(sch);
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2005-11-05 13:14:05 -07:00
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q->parms.qavg = red_calc_qavg(&q->parms, sch->qstats.backlog);
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2005-04-16 16:20:36 -06:00
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2005-11-05 13:14:05 -07:00
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if (red_is_idling(&q->parms))
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red_end_of_idle_period(&q->parms);
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2005-04-16 16:20:36 -06:00
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2005-11-05 13:14:05 -07:00
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switch (red_action(&q->parms, q->parms.qavg)) {
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case RED_DONT_MARK:
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break;
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2005-04-16 16:20:36 -06:00
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2005-11-05 13:14:05 -07:00
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case RED_PROB_MARK:
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sch->qstats.overlimits++;
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if (!red_use_ecn(q) || !INET_ECN_set_ce(skb)) {
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q->stats.prob_drop++;
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goto congestion_drop;
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}
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2005-04-16 16:20:36 -06:00
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2005-11-05 13:14:05 -07:00
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q->stats.prob_mark++;
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break;
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case RED_HARD_MARK:
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sch->qstats.overlimits++;
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if (!red_use_ecn(q) || !INET_ECN_set_ce(skb)) {
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q->stats.forced_drop++;
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goto congestion_drop;
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}
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q->stats.forced_mark++;
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break;
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2005-04-16 16:20:36 -06:00
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}
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2005-11-05 13:14:05 -07:00
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if (sch->qstats.backlog + skb->len <= q->limit) {
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__skb_queue_tail(&sch->q, skb);
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sch->qstats.backlog += skb->len;
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sch->bstats.bytes += skb->len;
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sch->bstats.packets++;
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return NET_XMIT_SUCCESS;
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2005-04-16 16:20:36 -06:00
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}
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2005-11-05 13:14:05 -07:00
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q->stats.pdrop++;
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kfree_skb(skb);
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sch->qstats.drops++;
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return NET_XMIT_DROP;
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congestion_drop:
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2005-04-16 16:20:36 -06:00
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kfree_skb(skb);
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sch->qstats.drops++;
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return NET_XMIT_CN;
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}
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static int
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red_requeue(struct sk_buff *skb, struct Qdisc* sch)
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{
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struct red_sched_data *q = qdisc_priv(sch);
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2005-11-05 13:14:05 -07:00
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if (red_is_idling(&q->parms))
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red_end_of_idle_period(&q->parms);
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2005-04-16 16:20:36 -06:00
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__skb_queue_head(&sch->q, skb);
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sch->qstats.backlog += skb->len;
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sch->qstats.requeues++;
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return 0;
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}
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static struct sk_buff *
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red_dequeue(struct Qdisc* sch)
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{
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struct sk_buff *skb;
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struct red_sched_data *q = qdisc_priv(sch);
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skb = __skb_dequeue(&sch->q);
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if (skb) {
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sch->qstats.backlog -= skb->len;
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return skb;
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}
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2005-11-05 13:14:05 -07:00
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red_start_of_idle_period(&q->parms);
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2005-04-16 16:20:36 -06:00
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return NULL;
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}
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static unsigned int red_drop(struct Qdisc* sch)
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{
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struct sk_buff *skb;
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struct red_sched_data *q = qdisc_priv(sch);
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skb = __skb_dequeue_tail(&sch->q);
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if (skb) {
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unsigned int len = skb->len;
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sch->qstats.backlog -= len;
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sch->qstats.drops++;
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2005-11-05 13:14:05 -07:00
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q->stats.other++;
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2005-04-16 16:20:36 -06:00
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kfree_skb(skb);
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return len;
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}
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2005-11-05 13:14:05 -07:00
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red_start_of_idle_period(&q->parms);
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2005-04-16 16:20:36 -06:00
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return 0;
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}
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static void red_reset(struct Qdisc* sch)
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{
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struct red_sched_data *q = qdisc_priv(sch);
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__skb_queue_purge(&sch->q);
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sch->qstats.backlog = 0;
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2005-11-05 13:14:05 -07:00
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red_restart(&q->parms);
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2005-04-16 16:20:36 -06:00
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}
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static int red_change(struct Qdisc *sch, struct rtattr *opt)
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{
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struct red_sched_data *q = qdisc_priv(sch);
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struct rtattr *tb[TCA_RED_STAB];
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struct tc_red_qopt *ctl;
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if (opt == NULL ||
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rtattr_parse_nested(tb, TCA_RED_STAB, opt) ||
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tb[TCA_RED_PARMS-1] == 0 || tb[TCA_RED_STAB-1] == 0 ||
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RTA_PAYLOAD(tb[TCA_RED_PARMS-1]) < sizeof(*ctl) ||
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RTA_PAYLOAD(tb[TCA_RED_STAB-1]) < 256)
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return -EINVAL;
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ctl = RTA_DATA(tb[TCA_RED_PARMS-1]);
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sch_tree_lock(sch);
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q->flags = ctl->flags;
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q->limit = ctl->limit;
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2005-11-05 13:14:05 -07:00
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red_set_parms(&q->parms, ctl->qth_min, ctl->qth_max, ctl->Wlog,
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ctl->Plog, ctl->Scell_log,
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RTA_DATA(tb[TCA_RED_STAB-1]));
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2005-07-08 15:57:23 -06:00
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if (skb_queue_empty(&sch->q))
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2005-11-05 13:14:05 -07:00
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red_end_of_idle_period(&q->parms);
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2005-04-16 16:20:36 -06:00
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sch_tree_unlock(sch);
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return 0;
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}
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static int red_init(struct Qdisc* sch, struct rtattr *opt)
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{
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return red_change(sch, opt);
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}
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static int red_dump(struct Qdisc *sch, struct sk_buff *skb)
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{
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struct red_sched_data *q = qdisc_priv(sch);
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unsigned char *b = skb->tail;
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struct rtattr *rta;
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2005-11-05 13:14:05 -07:00
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struct tc_red_qopt opt = {
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.limit = q->limit,
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.flags = q->flags,
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.qth_min = q->parms.qth_min >> q->parms.Wlog,
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.qth_max = q->parms.qth_max >> q->parms.Wlog,
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.Wlog = q->parms.Wlog,
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.Plog = q->parms.Plog,
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.Scell_log = q->parms.Scell_log,
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};
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2005-04-16 16:20:36 -06:00
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rta = (struct rtattr*)b;
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RTA_PUT(skb, TCA_OPTIONS, 0, NULL);
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RTA_PUT(skb, TCA_RED_PARMS, sizeof(opt), &opt);
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rta->rta_len = skb->tail - b;
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return skb->len;
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rtattr_failure:
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skb_trim(skb, b - skb->data);
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return -1;
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}
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static int red_dump_stats(struct Qdisc *sch, struct gnet_dump *d)
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{
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struct red_sched_data *q = qdisc_priv(sch);
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2005-11-05 13:14:05 -07:00
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struct tc_red_xstats st = {
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.early = q->stats.prob_drop + q->stats.forced_drop,
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.pdrop = q->stats.pdrop,
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.other = q->stats.other,
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.marked = q->stats.prob_mark + q->stats.forced_mark,
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};
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return gnet_stats_copy_app(d, &st, sizeof(st));
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2005-04-16 16:20:36 -06:00
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}
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static struct Qdisc_ops red_qdisc_ops = {
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.next = NULL,
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.cl_ops = NULL,
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.id = "red",
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.priv_size = sizeof(struct red_sched_data),
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.enqueue = red_enqueue,
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.dequeue = red_dequeue,
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.requeue = red_requeue,
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.drop = red_drop,
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.init = red_init,
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.reset = red_reset,
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.change = red_change,
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.dump = red_dump,
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.dump_stats = red_dump_stats,
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.owner = THIS_MODULE,
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};
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static int __init red_module_init(void)
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{
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return register_qdisc(&red_qdisc_ops);
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}
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static void __exit red_module_exit(void)
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{
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unregister_qdisc(&red_qdisc_ops);
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}
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module_init(red_module_init)
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module_exit(red_module_exit)
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MODULE_LICENSE("GPL");
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