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sch_fifo.c
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/*
* net/sched/sch_fifo.c The simplest FIFO queue.
*
* 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.
*
* Authors: Alexey Kuznetsov, <[email protected]>
*/
#include <linux/config.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <net/pkt_sched.h>
/* 1 band FIFO pseudo-"scheduler" */
struct fifo_sched_data
{
u32 limit;
};
static int bfifo_enqueue(struct sk_buff *skb, struct Qdisc* sch)
{
struct fifo_sched_data *q = qdisc_priv(sch);
if (likely(sch->qstats.backlog + skb->len <= q->limit))
return qdisc_enqueue_tail(skb, sch);
return qdisc_reshape_fail(skb, sch);
}
static int pfifo_enqueue(struct sk_buff *skb, struct Qdisc* sch)
{
struct fifo_sched_data *q = qdisc_priv(sch);
if (likely(skb_queue_len(&sch->q) < q->limit))
return qdisc_enqueue_tail(skb, sch);
return qdisc_reshape_fail(skb, sch);
}
static int fifo_init(struct Qdisc *sch, struct rtattr *opt)
{
struct fifo_sched_data *q = qdisc_priv(sch);
if (opt == NULL) {
u32 limit = sch->dev->tx_queue_len ? : 1;
if (sch->ops == &bfifo_qdisc_ops)
limit *= sch->dev->mtu;
q->limit = limit;
} else {
struct tc_fifo_qopt *ctl = RTA_DATA(opt);
if (RTA_PAYLOAD(opt) < sizeof(*ctl))
return -EINVAL;
q->limit = ctl->limit;
}
return 0;
}
static int fifo_dump(struct Qdisc *sch, struct sk_buff *skb)
{
struct fifo_sched_data *q = qdisc_priv(sch);
struct tc_fifo_qopt opt = { .limit = q->limit };
RTA_PUT(skb, TCA_OPTIONS, sizeof(opt), &opt);
return skb->len;
rtattr_failure:
return -1;
}
struct Qdisc_ops pfifo_qdisc_ops = {
.id = "pfifo",
.priv_size = sizeof(struct fifo_sched_data),
.enqueue = pfifo_enqueue,
.dequeue = qdisc_dequeue_head,
.requeue = qdisc_requeue,
.drop = qdisc_queue_drop,
.init = fifo_init,
.reset = qdisc_reset_queue,
.change = fifo_init,
.dump = fifo_dump,
.owner = THIS_MODULE,
};
struct Qdisc_ops bfifo_qdisc_ops = {
.id = "bfifo",
.priv_size = sizeof(struct fifo_sched_data),
.enqueue = bfifo_enqueue,
.dequeue = qdisc_dequeue_head,
.requeue = qdisc_requeue,
.drop = qdisc_queue_drop,
.init = fifo_init,
.reset = qdisc_reset_queue,
.change = fifo_init,
.dump = fifo_dump,
.owner = THIS_MODULE,
};
EXPORT_SYMBOL(bfifo_qdisc_ops);
EXPORT_SYMBOL(pfifo_qdisc_ops);