153 lines
3.5 KiB
C
153 lines
3.5 KiB
C
/*
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* net/sched/sch_fifo.c The simplest FIFO 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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#include <linux/module.h>
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/skbuff.h>
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#include <net/pkt_sched.h>
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/* 1 band FIFO pseudo-"scheduler" */
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struct fifo_sched_data
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{
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u32 limit;
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};
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static int bfifo_enqueue(struct sk_buff *skb, struct Qdisc* sch)
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{
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struct fifo_sched_data *q = qdisc_priv(sch);
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if (likely(sch->qstats.backlog + qdisc_pkt_len(skb) <= q->limit))
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return qdisc_enqueue_tail(skb, sch);
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return qdisc_reshape_fail(skb, sch);
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}
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static int pfifo_enqueue(struct sk_buff *skb, struct Qdisc* sch)
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{
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struct fifo_sched_data *q = qdisc_priv(sch);
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if (likely(skb_queue_len(&sch->q) < q->limit))
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return qdisc_enqueue_tail(skb, sch);
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return qdisc_reshape_fail(skb, sch);
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}
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static int fifo_init(struct Qdisc *sch, struct nlattr *opt)
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{
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struct fifo_sched_data *q = qdisc_priv(sch);
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if (opt == NULL) {
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u32 limit = qdisc_dev(sch)->tx_queue_len ? : 1;
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if (sch->ops == &bfifo_qdisc_ops)
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limit *= qdisc_dev(sch)->mtu;
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q->limit = limit;
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} else {
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struct tc_fifo_qopt *ctl = nla_data(opt);
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if (nla_len(opt) < sizeof(*ctl))
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return -EINVAL;
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q->limit = ctl->limit;
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}
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return 0;
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}
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static int fifo_dump(struct Qdisc *sch, struct sk_buff *skb)
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{
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struct fifo_sched_data *q = qdisc_priv(sch);
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struct tc_fifo_qopt opt = { .limit = q->limit };
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NLA_PUT(skb, TCA_OPTIONS, sizeof(opt), &opt);
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return skb->len;
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nla_put_failure:
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return -1;
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}
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struct Qdisc_ops pfifo_qdisc_ops __read_mostly = {
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.id = "pfifo",
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.priv_size = sizeof(struct fifo_sched_data),
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.enqueue = pfifo_enqueue,
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.dequeue = qdisc_dequeue_head,
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.requeue = qdisc_requeue,
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.drop = qdisc_queue_drop,
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.init = fifo_init,
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.reset = qdisc_reset_queue,
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.change = fifo_init,
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.dump = fifo_dump,
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.owner = THIS_MODULE,
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};
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EXPORT_SYMBOL(pfifo_qdisc_ops);
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struct Qdisc_ops bfifo_qdisc_ops __read_mostly = {
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.id = "bfifo",
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.priv_size = sizeof(struct fifo_sched_data),
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.enqueue = bfifo_enqueue,
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.dequeue = qdisc_dequeue_head,
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.requeue = qdisc_requeue,
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.drop = qdisc_queue_drop,
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.init = fifo_init,
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.reset = qdisc_reset_queue,
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.change = fifo_init,
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.dump = fifo_dump,
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.owner = THIS_MODULE,
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};
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EXPORT_SYMBOL(bfifo_qdisc_ops);
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/* Pass size change message down to embedded FIFO */
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int fifo_set_limit(struct Qdisc *q, unsigned int limit)
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{
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struct nlattr *nla;
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int ret = -ENOMEM;
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/* Hack to avoid sending change message to non-FIFO */
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if (strncmp(q->ops->id + 1, "fifo", 4) != 0)
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return 0;
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nla = kmalloc(nla_attr_size(sizeof(struct tc_fifo_qopt)), GFP_KERNEL);
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if (nla) {
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nla->nla_type = RTM_NEWQDISC;
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nla->nla_len = nla_attr_size(sizeof(struct tc_fifo_qopt));
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((struct tc_fifo_qopt *)nla_data(nla))->limit = limit;
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ret = q->ops->change(q, nla);
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kfree(nla);
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}
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return ret;
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}
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EXPORT_SYMBOL(fifo_set_limit);
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struct Qdisc *fifo_create_dflt(struct Qdisc *sch, struct Qdisc_ops *ops,
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unsigned int limit)
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{
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struct Qdisc *q;
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int err = -ENOMEM;
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q = qdisc_create_dflt(qdisc_dev(sch), sch->dev_queue,
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ops, TC_H_MAKE(sch->handle, 1));
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if (q) {
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err = fifo_set_limit(q, limit);
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if (err < 0) {
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qdisc_destroy(q);
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q = NULL;
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}
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}
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return q ? : ERR_PTR(err);
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}
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EXPORT_SYMBOL(fifo_create_dflt);
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